JP6780313B2 - Pressure booster for aerial work platforms - Google Patents

Description

The present invention relates to a pressure booster. More specifically, the present invention relates to a pressure booster for aerial work platforms that supplies boosted hydraulic oil to hydraulic tools.

Conventionally, aerial work platforms are known in which a bucket on which an operator is boarded is provided at the tip of a telescopic boom. The aerial work platform is configured so that hydraulic oil can be supplied to hydraulic equipment such as hydraulic tools in the bucket. The aerial work platform for electrical wiring work is configured to be able to supply hydraulic oil to a hydraulic crimping tool, which is a hydraulic tool that connects power lines by crimping a sleeve for electrical wiring. In the aerial work platform configured in this way, a pressure boosting device for supplying the pressure boosted hydraulic oil is provided. For example, as described in Patent Document 1.

The pressure booster for aerial work platforms described in Patent Document 1 controls the pressure boosting cylinder by switching between the directional control valve on the upstream side and the directional control valve on the downstream side to boost the hydraulic pressure of the hydraulic oil. In the pressure booster, a downstream directional control valve is connected in series to an upstream directional control valve to which hydraulic oil is supplied from a hydraulic pump. The directional control valve on the upstream side selectively supplies hydraulic oil to the rod side oil chamber of the booster cylinder to perform a return operation of the hydraulic crimping tool, and a state of supplying hydraulic oil to the directional control valve on the downstream side. It is configured to switch. The directional control valve on the downstream side supplies the hydraulic oil to the hydraulic crimping tool without boosting the pressure to temporarily hold the hydraulic crimping tool, and supplies the hydraulic oil to the oil chamber on the head side of the boosting cylinder. It is configured to selectively switch to the state where the hydraulic oil is increased and the main compression operation of the hydraulic crimping tool is performed.

In the pressure booster described in Patent Document 1, the pressure booster cylinder is provided with a pressure switch for detecting whether or not the pressure in the pressure booster chamber exceeds a predetermined pressure, and the pressure switch is a predetermined pressure. For example, when it is detected that the specified pressure has been exceeded, or when the return operation is switched by an operation switch or the like, the control means switches between the upstream directional control valve and the downstream directional control valve, and discharges hydraulic oil from the crimping tool. Perform a return operation. However, for example, when the pressure switch fails, it is not possible to normally determine whether or not the pressure in the booster chamber exceeds a predetermined pressure, and unless a separate operation is performed, the directional control valve on the upstream side And there was a risk that the pressure increase would continue without switching the directional control valve on the downstream side.

Japanese Unexamined Patent Publication No. 2014-20543

An object of the present invention is to provide a pressure boosting device for aerial work platforms that can release the pressure boosting state without the need for a separate operation even when the detection means for detecting pressure fails. To do.

The problem to be solved by the present invention is as described above, and next, the means for solving this problem will be described.

That is, the pressure booster for the high-altitude work vehicle is a pressure booster for the high-altitude work vehicle that supplies the hydraulic oil boosted by the pressure-increasing cylinder to the hydraulic tool. A supply oil passage for connecting a hydraulic tool, an electromagnetic switching valve for preload connected to the supply oil passage, and an electromagnetic switching valve for main pressure connected to the pressure boosting cylinder are provided as a hydraulic source. A state in which the electromagnetic switching valve for preload and the electromagnetic switching valve for main pressure are connected in parallel, and the electromagnetic switching valve for preload supplies hydraulic oil to the supply oil passage through the preload oil passage, and the supply oil. A state in which the hydraulic oil is selectively switchable between a state in which hydraulic oil is not supplied to the road and a state in which the electromagnetic switching valve for the main pressure supplies hydraulic oil to the oil chamber on the head side of the pressure boosting cylinder through the pressure boosting oil passage. A pressure sensor is provided in the pressure boosting chamber of the pressure boosting cylinder, and the hydraulic oil is selectively switched between the state of supplying hydraulic oil to the rod side oil chamber of the pressure boosting cylinder through the decompression oil passage. When the detection value of the pressure sensor reaches the preload reference value while the electromagnetic switching valve for preload is switched to the state of supplying hydraulic oil to the supply oil passage through the preload oil passage, the preload is used. The electromagnetic switching valve is switched to a state in which hydraulic oil is not supplied, and the electromagnetic switching valve for main pressure is switched to a state in which hydraulic oil is supplied to the oil chamber on the head side of the boosting cylinder through the boosting oil passage. When the electromagnetic switching valve for main pressure is switched to a state in which hydraulic oil is supplied to the oil chamber on the head side of the pressure boosting cylinder through the pressure boosting oil passage, the detected value of the pressure sensor becomes the main pressure reference value. When it reaches, the electromagnetic switching valve for the main pressure is switched to a state of supplying hydraulic oil to the rod side oil chamber of the boosting cylinder through the decompression oil passage, and the electromagnetic switching valve for the main pressure is the pressure boosting cylinder. When the detection value of the pressure sensor does not reach the main pressure reference value when the hydraulic oil is supplied to the head side oil chamber through the pressure boosting oil passage, the pressure boosting cylinder When the time from starting the supply of hydraulic oil to the oil chamber on the head side through the booster oil passage exceeds a predetermined time, the electromagnetic switching valve for the main pressure depressurizes the oil chamber on the rod side of the booster cylinder. It can be switched to a state where hydraulic oil is supplied through the oil passage.

In the pressure booster for high-altitude work vehicles, the hydraulic tool is provided with a tool-side pressure sensor , and the electromagnetic switching valve for the main pressure passes the hydraulic oil through the pressure-increasing oil passage to the head-side oil chamber of the pressure-increasing cylinder. when being switched to a state for supplying, when the detection value of the pressure sensor, the difference between the detected value of the tool-side pressure sensor is a predetermined value or more, or a detection value of the pressure sensor, the When the difference from the value detected by the tool-side pressure sensor is less than a predetermined value, the time after starting the supply of hydraulic oil to the head-side oil chamber of the booster cylinder through the booster oil passage is predetermined. When the time is exceeded, the electromagnetic switching valve for the main pressure is switched to a state in which hydraulic oil is supplied to the rod-side oil chamber of the boosting cylinder through the pressure reducing oil passage.

The pressure booster for aerial work platforms is provided with a warning means for warning of an abnormality, and the electromagnetic switching valve for the main pressure supplies hydraulic oil to the rod side oil chamber of the pressure booster cylinder through the pressure reducing oil passage. When the state is switched to the above-mentioned state, an abnormality is warned by the notification means.

In the pressure booster for high-altitude work vehicles, the electromagnetic switching valve for the main pressure is switched to a state in which hydraulic oil is supplied to the rod-side oil chamber of the pressure boosting cylinder through the decompression oil passage, and again for the main pressure. When the detection value of the pressure sensor does not reach the main pressure reference value when the electromagnetic switching valve is switched to a state of supplying hydraulic oil to the oil chamber on the head side of the pressure boosting cylinder through the pressure boosting oil passage. When the time from starting the supply of hydraulic oil to the head side oil chamber of the booster cylinder through the booster oil passage exceeds the second predetermined time, the electromagnetic switching valve for the main pressure is activated. The state is switched to a state in which hydraulic oil is supplied to the rod-side oil chamber of the pressure boosting cylinder through the decompression oil passage, and the second predetermined time is set to be shorter than the predetermined time.

The present invention has the following effects.

In the pressure booster for aerial work vehicles, the value detected by the pressure sensor is the main pressure reference when the hydraulic oil is supplied to the oil chamber on the head side of the pressure booster cylinder through the booster oil passage. If the value is not reached and the time after starting the supply of hydraulic oil to the oil chamber on the head side of the boosting cylinder through the boosting oil passage exceeds a predetermined time, the electromagnetic switching valve for main pressure is described above. Since the oil chamber on the rod side of the boosting cylinder is switched to a state in which hydraulic oil is supplied through the decompression oil passage, when the pressure sensor fails and the detected value of the pressure sensor does not reach the main pressure reference value. Even if there is, the pressure boosting state can be released without the need for a separate operation.

In the pressure booster for high-altitude work vehicles, when the difference between the detection value of the pressure sensor and the detection value of the tool side pressure sensor is less than a predetermined value , the oil on the head side of the pressure boost cylinder When the time from starting the supply of hydraulic oil to the chamber through the pressure boosting oil passage exceeds a predetermined time, the electromagnetic switching valve for main pressure operates through the pressure reducing oil passage in the rod side oil chamber of the pressure boosting cylinder. Since the state is switched to the oil supply state, the pressure boosting state can be released without the need for a separate operation even when the hydraulic oil is not normally supplied to the external hydraulic device.

In the pressure boosting device for aerial work platforms, the warning means warns the operator that the pressure boosting state is not released normally.

In the pressure booster for aerial work platforms, the time until the second pressure boosting state is released is shorter than the time until the first pressure boosting state is released. Therefore, the pressure sensor or the external hydraulic pressure is released again. When it is determined that there is an abnormality in the device, the pressure boosting state can be released early, so that wasteful work time can be shortened and maintenance time can be secured.

The side view which shows the whole structure of the aerial work platform which concerns on one Embodiment of this invention. The figure which shows the hydraulic circuit of the pressure booster for the aerial work platform which concerns on one Embodiment of this invention. The figure which shows the control structure of the pressure booster for aerial work platforms which concerns on one Embodiment of this invention. The process drawing which shows the operation mode of the hydraulic crimping tool connected to the pressure booster for the aerial work platform which concerns on one Embodiment of this invention. The figure which shows the operation mode of the hydraulic circuit at the time of the temporary holding operation in the pressure booster for the aerial work platform which concerns on one Embodiment of this invention. The figure which shows the operation mode of the hydraulic circuit of the preload stage at the time of this compression operation in the pressure booster for aerial work platforms which concerns on one Embodiment of this invention. The figure which shows the operation mode of the hydraulic circuit of the main pressure stage at the time of this compression operation in the pressure booster for aerial work platforms which concerns on one Embodiment of this invention. The figure which shows the operation mode of the hydraulic circuit at the time of the return operation in the pressure booster for the aerial work platform which concerns on one Embodiment of this invention. The figure which shows the hydraulic circuit of the pressure booster for the aerial work platform which concerns on another embodiment of this invention. The figure which shows the flowchart which shows the control mode of the pressure booster for aerial work platforms which concerns on one Embodiment of this invention. The figure which shows the flowchart which shows the control mode of the pressure booster for aerial work platforms which concerns on one Embodiment of this invention. The figure which shows the flowchart which shows the control mode of the pressure booster for aerial work platforms which concerns on another embodiment of this invention. The figure which shows the flowchart which shows the control mode of the pressure booster for aerial work platforms which concerns on still another Embodiment of this invention. The figure which shows the flowchart which shows the control mode of the pressure booster for the aerial work platform which concerns on still another Embodiment of this invention.

Hereinafter, the aerial work platform 1 according to the embodiment of the aerial work platform will be described with reference to FIG.

As shown in FIG. 1, the aerial work platform 1 is an aerial work platform for electrical wiring work in which a sleeve is crimped using a hydraulic crimping tool 100 (see FIG. 2), which is a hydraulic tool, to connect power lines to each other. is there. The aerial work platform 1 has a vehicle 2 and an aerial work platform 6.

The vehicle 2 conveys the aerial work platform 6. The vehicle 2 is provided with a driver's cab 2b and a plurality of wheels 3 in a frame 2a, and is equipped with an engine 4 (see FIG. 2) as a power source. The vehicle 2 is configured to travel by transmitting the driving force of the engine 4 to the plurality of wheels 3 according to the operation from the driver's cab 2b. The vehicle 2 is provided with an outrigger 5. The outrigger 5 is composed of an overhang beam that can be extended by hydraulic pressure on both sides of the vehicle 2 in the width direction and a hydraulic jack cylinder that can be extended in a direction perpendicular to the ground. The vehicle 2 can expand the workable range of the aerial work platform 1 by extending the outrigger 5 in the width direction of the vehicle 2 and grounding the jack cylinder.

The aerial work platform 6 lifts the bucket 9 on which the worker is boarding to a high place. The aerial work platform 6 includes a swivel base 7, a telescopic boom 8, a bucket 9, an undulating cylinder 10, and an operating device 11.

The swivel base 7 swivels the aerial work platform 6. The swivel base 7 is provided on the frame 2a of the vehicle 2 via an annular bearing. The annular bearing is arranged so that its center of rotation is perpendicular to the installation surface of the vehicle 2. The swivel base 7 is rotatably configured with the center of the annular bearing as the center of rotation. Further, the swivel base 7 is configured to be rotated by a hydraulic swivel motor (not shown).

The telescopic boom 8 supports the bucket 9. The telescopic boom 8 is composed of a plurality of boom members. Each boom member is formed in a hollow cylindrical shape having polygonal cross sections similar to each other. Each boom member is formed in a size that can be inserted into the boom member in the order of the size of the cross-sectional area. The telescopic boom 8 is configured so that each boom member can move in the axial direction. That is, the telescopic boom 8 is configured to be telescopic by moving each boom member with a telescopic cylinder or the like (not shown). The telescopic boom 8 is provided so that the base end of the boom member can swing on the swivel base 7. Further, the telescopic boom 8 is configured to swing around the base end of the boom member with respect to the swivel base 7.

The bucket 9 is for securing a working space for an operator. The bucket 9 is configured so that an operator can get inside. The bucket 9 is supported by the tip of the telescopic boom 8 via a support mechanism 9a. The support mechanism 9a swings the bucket 9 in the elevation and horizontal directions by a hydraulic actuator (not shown).

The undulating cylinder 10 raises and lays down the telescopic boom 8 to maintain the posture of the telescopic boom 8. The undulating cylinder 10 is composed of a hydraulic cylinder. The base of the undulating cylinder 10 is oscillatingly connected to the swivel base 7, and the rod tip is oscillatingly connected to the telescopic boom 8. The undulating cylinder 10 erects or undulates the telescopic boom 8 by expanding and contracting the rod.

The operating device 11 operates the swivel base 7, the telescopic boom 8, the bucket 9, and the like. The operating device 11 is provided inside the vehicle 2 and the bucket 9. The operation device 11 is provided with a swivel expansion / contraction operation tool for performing a swivel operation of the swivel base 7, an expansion / contraction operation of the expansion / contraction boom 8, an undulation operation tool for performing an undulation operation of the expansion / contraction boom 8, an engine start switch, and the like. Further, the operating device 11 is provided with a hydraulic switching operating tool 11a (see FIG. 3) for switching the hydraulic pressure of the hydraulic oil supplied to the hydraulic crimping tool 100. The hydraulic switching operating tool 11a switches to a state in which increased pressure hydraulic oil can be supplied to the hydraulic crimping tool 100, and discharges hydraulic oil from the hydraulic crimping tool 100.

The aerial work platform 1 configured in this way can move the aerial work platform 6 to an arbitrary position by running the vehicle 2. Further, in the aerial work platform 1, the telescopic boom 8 is erected at an arbitrary undulating angle by the undulating cylinder 10, the telescopic boom 8 is extended to an arbitrary boom length, and the moving range of the bucket 9 of the aerial work platform 6 is extended. Can be expanded.

Hereinafter, the pressure booster 12 included in the aerial work platform 1 will be described with reference to FIGS. 2 and 3.

As shown in FIG. 2, the pressure booster 12 boosts the hydraulic pressure of the hydraulic oil supplied to the hydraulic crimping tool 100. The pressure boosting device 12 includes a pressure boosting cylinder 13, a pressure sensor 14, a preload electromagnetic switching valve (preload switching valve 17) which is a directional control valve, a relief valve 21, and a main pressure electromagnetic switching valve (direction control valve). It includes a main pressure switching valve 24), a pilot check valve 27, a hydraulic pump 28, and a control device 31 (see FIG. 3).

The pressure boosting cylinder 13 boosts the hydraulic pressure of the hydraulic oil. The pressure boosting cylinder 13 is composed of a hydraulic cylinder provided with a bottomed cylindrical pressure boosting chamber 13a provided on the rod side. The pressure boosting cylinder 13 is configured so that the inner diameter of the pressure boosting chamber 13a is smaller than the inner diameter of the hydraulic cylinder. A large-diameter piston 13d to which the rod 13f is connected is slidably inserted inside the hydraulic cylinder. Inside the hydraulic cylinder, a rod-side oil chamber 13b and a head-side oil chamber 13c are configured. A small-diameter piston 13e is slidably inserted inside the pressure boosting chamber 13a. In the pressure boosting cylinder 13, the small diameter piston 13e in the pressure boosting chamber 13a and the large diameter piston 13d in the hydraulic cylinder are connected via a rod 13f. When hydraulic oil is supplied to the oil chamber 13c on the head side of the hydraulic cylinder, the pressure boosting cylinder 13 transmits the force generated in the large diameter piston 13d by the hydraulic pressure of the hydraulic oil to the small diameter piston 13e in the pressure boosting chamber 13a. As a result, the pressure boosting cylinder 13 pressurizes the hydraulic oil in the pressure boosting chamber 13a by the force boosted by the area ratio of the large diameter piston 13d and the small diameter piston 13e.

A pressure sensor 14 is connected to the pressure boosting chamber 13a of the pressure boosting cylinder 13. The pressure sensor 14 can detect the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a in real time. The pressure sensor 14 is connected to the control device 31. Further, a supply oil passage 15 is connected to the pressure boosting chamber 13a of the pressure boosting cylinder 13. The supply oil passage 15 is provided with a joint 16 to which the hydraulic crimping tool 100 can be connected. As a result, the pressure booster 12 is configured so that the hydraulic oil boosted in the pressure boosting chamber 13a of the pressure booster cylinder 13 can be supplied to the hydraulic crimping tool 100 connected to the joint 16 through the supply oil passage 15. ..

The preload electromagnetic switching valve (hereinafter, simply referred to as “preload switching valve 17”), which is a directional control valve, is a supply in which the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100 are connected to each other. It switches the direction of the hydraulic oil supplied to the oil passage 15. A supply oil passage 15 is connected to one port of the preload switching valve 17 via a low pressure oil passage 18. A supply oil passage 15 is connected to the other port of the preload switching valve 17 via a preload oil passage 19. A hydraulic pump 28 is connected to the supply port of the preload switching valve 17 via a discharge oil passage 20. That is, the hydraulic oil is supplied to the preload switching valve 17 at the discharge pressure of the hydraulic pump 28 (hereinafter, simply referred to as “preload”). In the preload switching valve 17, one of one port and the other port is communicated with the supply port by moving a spool (not shown) by an electromagnet.

A relief valve 21 that controls the hydraulic pressure of the hydraulic oil to a set value or less is connected to the low-pressure oil passage 18 connected to one port of the preload switching valve 17. In the relief valve 21, a branch oil passage branched from the low pressure oil passage 18 is connected to the inlet port, and a hydraulic oil tank 30 is connected to the outlet port. Further, the low pressure oil passage 18 is provided with a throttle 22 on the upstream side of the branch oil passage of the relief valve 21, and a check valve 23 on the downstream side. When the hydraulic pressure of the hydraulic oil flowing through the low-pressure oil passage 18 reaches a set value, the relief valve 21 returns a part of the hydraulic oil flowing through the low-pressure oil passage 18 to the hydraulic oil tank 30 through the branch oil passage. That is, the hydraulic pressure of the hydraulic oil flowing through the low-pressure oil passage 18 is controlled by the relief valve 21 to a relief pressure lower than the preload (hereinafter, simply referred to as “low pressure”). Further, the flow rate of hydraulic oil flowing through the low-pressure oil passage 18 is limited to the relief flow rate of the relief valve 21 or less by the throttle 22. A check valve 23 is provided in the preload oil passage 19. The preload switching valve 17 is connected to the control device 31.

The preload switching valve 17 is in a state in which the low pressure oil passage 18 and the preload oil passage 19 are connected to the hydraulic oil tank 30 when the electromagnet is not excited (when the operation signal is not received from the control device 31). The spool is moved to position II. That is, the preload switching valve 17 is switched to a state in which the hydraulic oil discharged from the hydraulic pump 28 is not supplied to the supply oil passage 15. As a result, the pressure booster 12 does not supply hydraulic oil to the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100 through the oil supply passage 15.

The preload switching valve 17 has a low-pressure oil passage when an electromagnet is excited so that one port and a supply port communicate with each other (when an operation signal for supplying low-pressure hydraulic oil is received from the control device 31). The spool is moved to the I position where 18 is connected to the discharge oil passage 20 and the preload oil passage 19 is connected to the hydraulic oil tank 30. That is, the preload switching valve 17 is switched to a state in which hydraulic oil is supplied to the supply oil passage 15 through the low pressure oil passage 18. As a result, the pressure booster 12 supplies the low pressure hydraulic oil to the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100 through the supply oil passage 15. At this time, the flow rate of the hydraulic oil supplied to the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100 is limited by the throttle 22 of the low pressure oil passage 18.

The preload switching valve 17 has a preload oil passage when the electromagnet is excited so that the other port and the supply port communicate with each other (when an operation signal for supplying the preload hydraulic oil is received from the control device 31). The spool is moved to position III in which 19 is connected to the discharge oil passage 20 and the low pressure oil passage 18 is connected to the hydraulic oil tank 30. That is, the preload switching valve 17 is switched to a state in which hydraulic oil is supplied to the supply oil passage 15 through the preload oil passage 19. As a result, the pressure booster 12 supplies the hydraulic oil of the preload to the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100 through the supply oil passage 15.

The main pressure electromagnetic switching valve (hereinafter, simply referred to as “main pressure switching valve 24”), which is a directional control valve, switches the direction of the hydraulic oil supplied to the pressure boosting cylinder 13. A rod-side oil chamber 13b of the pressure boosting cylinder 13 is connected to one port of the main pressure switching valve 24 via a pressure reducing oil passage 25. The head side oil chamber 13c of the pressure boosting cylinder 13 is connected to the other port of the main pressure switching valve 24 via the pressure boosting oil passage 26. A hydraulic pump 28 is connected to the supply port of the main pressure switching valve 24 via a discharge oil passage 20. That is, hydraulic oil is supplied to the main pressure switching valve 24 with a preload. In the main pressure switching valve 24, one of one port and the other port is communicated with the supply port by moving a spool (not shown) by an electromagnet. The main pressure switching valve 24 is connected to the control device 31.

The main pressure switching valve 24 is in a state where the decompression oil passage 25 and the pressure boosting oil passage 26 are connected to the hydraulic oil tank 30 when the electromagnet is not excited (when the operation signal is not received from the control device 31). The spool is moved to a certain II position. That is, the main pressure switching valve 24 is switched to a state in which the hydraulic oil discharged from the hydraulic pump 28 is not supplied to the pressure boosting cylinder 13. As a result, the pressure boosting device 12 does not boost the hydraulic pressure of the hydraulic oil by the pressure boosting cylinder 13.

The main pressure switching valve 24 has a pressure reducing oil passage when an electromagnet is excited so that one port and a supply port communicate with each other (when an operation signal for reducing the hydraulic pressure of the hydraulic oil is received from the control device 31). The spool is moved to the I position where 25 is connected to the discharge oil passage 20 and the pressure boosting oil passage 26 is connected to the hydraulic oil tank 30. That is, the main pressure switching valve 24 is switched to a state in which hydraulic oil is supplied to the rod side oil chamber 13b of the pressure increasing cylinder 13 through the pressure reducing oil passage 25. As a result, the pressure boosting device 12 moves the small diameter piston 13e in the direction in which the volume of the pressure boosting chamber 13a increases to reduce the hydraulic pressure of the hydraulic oil.

The main pressure switching valve 24 is used when the electromagnet is excited so that the other port and the supply port communicate with each other (when an operation signal for increasing the hydraulic pressure of the hydraulic oil is received from the control device 31). The spool is moved to position III in which the passage 26 is connected to the discharge oil passage 20 and the decompression oil passage 25 is connected to the hydraulic oil tank 30. That is, the main pressure switching valve 24 is switched to a state in which hydraulic oil is supplied to the head side oil chamber 13c of the pressure boosting cylinder 13 through the pressure boosting oil passage 26. As a result, the pressure boosting device 12 moves the small diameter piston 13e in the direction in which the volume of the pressure boosting chamber 13a decreases to increase the hydraulic pressure of the hydraulic oil.

The pilot check valve 27 opens the oil passage. In the pilot type check valve 27, the supply oil passage 15 is connected to the inlet port, and the hydraulic oil tank 30 is connected to the outlet port. Further, the pilot type check valve 27 is configured so that the pilot hydraulic oil is supplied from the pressure reducing oil passage 25. When the main pressure switching valve 24 is switched to a state of supplying hydraulic oil to the rod side oil chamber 13b of the boosting cylinder 13, the pilot type check valve 27 is opened by supplying hydraulic oil for pilot from the decompression oil passage 25. To speak. The hydraulic oil in the pressure boosting chamber 13a connected to the supply oil passage 15 and the hydraulic oil in the hydraulic crimping tool 100 are returned to the hydraulic oil tank 30 through the pilot check valve 27. As a result, the pressure booster 12 is configured to be able to quickly discharge the hydraulic oil in the pressure boosting chamber 13a and the hydraulic oil in the hydraulic crimping tool 100.

The hydraulic pump 28 discharges hydraulic oil at a predetermined discharge pressure. The hydraulic pump 28 is driven by the engine 4. A preload switching valve 17 and a main pressure switching valve 24 are connected in parallel to the hydraulic pump 28. The hydraulic oil discharged from the hydraulic pump 28 is supplied to the preload switching valve 17 and the main pressure switching valve 24 through the discharge oil passage 20, respectively. A relief valve 29 for a hydraulic pump is provided in the discharge oil passage 20. The relief valve 29 for the hydraulic pump controls the hydraulic pressure of the hydraulic oil discharged from the hydraulic pump 28 to a set value or less.

As shown in FIG. 3, the control device 31 controls the operation of the preload switching valve 17 and the main pressure switching valve 24 of the pressure boosting device 12. The control device 31 may actually have a configuration in which a CPU, ROM, RAM, HDD, etc. are connected by a bus, or may have a configuration including a one-chip LSI or the like. The control device 31 stores various programs and data for controlling the operation of the preload switching valve 17 and the main pressure switching valve 24. The control device 31 is provided in the vehicle 2. Further, a warning means 33 for warning an abnormality is connected to the control device 31. The warning means 33 is a means for warning an abnormality of the hydraulic crimping tool 100 or the pressure sensor 14, and is composed of, for example, a speaker that warns by voice, a lamp that warns by light, and the like.

The control device 31 is connected to the hydraulic pressure switching operation tool 11a, and can acquire an operation signal from the hydraulic pressure switching operation tool 11a.

The control device 31 is connected to the pressure sensor 14 of the pressure boosting chamber 13a, and can acquire the detected value of the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a detected by the pressure sensor 14.

The control device 31 is connected to the preload switching valve 17, and can selectively excite the electromagnet of the preload switching valve 17 to change the position of the spool of the preload switching valve 17.

The control device 31 is connected to the main pressure switching valve 24, and can selectively excite the electromagnet of the main pressure switching valve 24 to change the position of the spool of the main pressure switching valve 24.

The control device 31 is connected to the tool operating tool 100c of the hydraulic crimping tool 100 via the connector 31a, and can acquire an operation signal from the hydraulic crimping tool 100.

The control device 31 is connected to the warning means 33, and when there is an abnormality in the hydraulic crimping tool 100 or the pressure sensor 14, the operator can be warned of the abnormality.

In this way, the pressure booster 12 of the aerial work platform 1 is configured as an oil passage in which the low-pressure oil passage whose hydraulic pressure is controlled by the relief valve 21 and the preload oil passage 19 in which the relief valve 21 is not provided are independent of each other. ing. That is, the pressure booster 12 can set the hydraulic pressure and the flow rate of the hydraulic oil flowing through the low pressure oil passage 18 and the hydraulic oil flowing through the preload oil passage 19 to different values. As a result, the pressure booster 12 does not provide a directional control valve for the relief valve 21 for hydraulic pressure switching, and only supplies the hydraulic oil controlled to a hydraulic pressure equal to or lower than a predetermined value by the action of the relief valve 21. It can be suppressed. That is, the pressure booster 12 can supply the boosted hydraulic oil to the hydraulic crimping tool 100 without limiting the flow rate.

In the present embodiment, the pressure boosting cylinder 13 of the pressure booster 12 of the aerial work platform 1, the preload switching valve 17, the relief valve 21, the main pressure switching valve 24, the pilot check valve 27, the hydraulic pump 28 and the control The device 31 is provided on the vehicle 2 of the aerial work platform 1. In the pressure booster 12, the hydraulic hose constituting the supply oil passage 15 is piped to the bucket 9 via the telescopic boom 8. A joint 16 for connecting a hydraulic crimping tool or the like is provided at the tip of the hydraulic hose.

Next, the operation mode of the pressure booster 12 in the caulking work of the sleeve S for electrical wiring by the hydraulic crimping tool 100 will be described with reference to FIGS. 2 and 4 to 8. In the present embodiment, the pressure booster 12 has a hydraulic crimping tool 100 connected to a joint 16 and a tool operating tool 100c of the hydraulic crimping tool 100 connected to a control device 31 via a connector 31a. To do.

As shown in FIG. 4, the hydraulic crimping tool 100 connected to the pressure booster 12 grips and crimps the sleeve S for electrical wiring. The hydraulic crimping tool 100 is configured such that the movable portion 100a moves toward the receiving portion 100b by the hydraulic oil supplied from the pressure boosting device 12. In the hydraulic crimping tool 100, the movable portion 100a is stopped in the stopped state s0 by the operation of the tool operating tool 100c, the movable portion 100a is moved toward the receiving portion 100b, and the sleeve S is moved to the movable portion 100a and the receiving portion 100b. The temporary holding operation s1 to be gripped by the above, the preloading step s2 of the main compression operation in which the movable portion 100a is pressed by a predetermined force to preload the sleeve S, and the movable portion 100a is pressed by a predetermined force to press the sleeve S. The main pressure step s3 of the main compression operation of caulking and the return operation s4 in which the movable portion 100a is moved away from the receiving portion 100b to release the sleeve S can be performed.

As shown in FIG. 2, when the operation mode of the hydraulic crimping tool 100 is switched to the stopped state by the operation of the tool operating tool 100c, the control device 31 sets the spool position of the preload switching valve 17 to the low pressure oil passage 18 And the preload oil passage 19 are moved to the II position where the hydraulic oil tank 30 is connected. At the same time, the control device 31 moves the spool position of the main pressure switching valve 24 to the position II in which the pressure reducing oil passage 25 and the pressure increasing oil passage 26 are connected to the hydraulic oil tank 30. That is, the pressure booster 12 does not supply hydraulic oil to the hydraulic crimping tool 100. As a result, the hydraulic crimping tool 100 stops in a state where the movable portion 100a is separated from the receiving portion 100b (a state in which the sleeve S is released).

As shown in FIG. 5, when the operation mode of the hydraulic crimping tool 100 is switched to the temporary holding operation s1 by the operation of the tool operating tool 100c, the control device 31 sets the spool position of the preload switching valve 17 to low pressure oil. The passage 18 is connected to the discharge oil passage 20, and the preload oil passage 19 is moved to the I position where it is connected to the hydraulic oil tank 30. At the same time, the control device 31 moves the spool position of the main pressure switching valve 24 to the position II in which the pressure reducing oil passage 25 and the pressure increasing oil passage 26 are connected to the hydraulic oil tank 30. That is, in the pressure booster 12, the hydraulic pressure is controlled to a low pressure by the relief valve 21, and the hydraulic oil whose flow rate is controlled to be equal to or lower than the relief flow rate by the throttle 22 is used with the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100. (See the light ink part). As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved toward the receiving portion 100b, and the sleeve S is gripped by the movable portion 100a and the receiving portion 100b (see the black arrow). At the same time, the pressure booster 12 discharges air in the pressure boosting chamber 13a, the hydraulic crimping tool 100, and the supply oil passage 15 by supplying low-pressure hydraulic oil.

As shown in FIG. 6, when the operation mode of the hydraulic crimping tool 100 is switched to the present compression operation by the operation of the tool operating tool 100c, the control device 31 sets the spool position of the preload switching valve 17 to the preload oil passage. 19 is connected to the discharge oil passage 20, and the low pressure oil passage 18 is moved to the position III in which it is connected to the hydraulic oil tank 30. At the same time, the control device 31 moves the spool position of the main pressure switching valve 24 to the position II in which the pressure reducing oil passage 25 and the pressure increasing oil passage 26 are connected to the hydraulic oil tank 30. That is, the pressure booster 12 supplies the hydraulic oil of the preload, which is the discharge pressure of the hydraulic pump 28, to the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100 (see the thin ink portion). As a result, in the hydraulic crimping tool 100, as the preload step s2 of the main compression operation, the movable portion 100a is pressed by a predetermined force by the hydraulic oil of the preload that is not boosted, and the preload is applied to the sleeve S (black arrow). reference). At the same time, the pressure booster 12 discharges the air in the pressure boosting chamber 13a, the hydraulic crimping tool 100, and the supply oil passage 15 by supplying the hydraulic oil of the preload.

As shown in FIG. 7, when the detected value of the pressure sensor 14 reaches the preload reference value in the preload step s2 of this compression operation, the control device 31 sets the spool position of the preload switching valve 17 to the low pressure oil passage 18. The preload oil passage 19 is moved to the II position where it is connected to the hydraulic oil tank 30. At the same time, the control device 31 sets the spool position of the main pressure switching valve 24 to the position III in which the boosting oil passage 26 is connected to the discharge oil passage 20 and the pressure reducing oil passage 25 is connected to the hydraulic oil tank 30. Move. That is, the pressure boosting device 12 reduces the volume of the pressure boosting chamber 13a of the pressure boosting cylinder 13 to increase the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a and supplies it to the hydraulic crimping tool 100 (see the light ink portion). .. As a result, in the hydraulic crimping tool 100, as the main pressure step s3 of the main compression operation, the movable portion 100a is pressed by the hydraulic oil boosted by the pressure boosting cylinder 13 with a predetermined force to crimp the sleeve S (black). See painted arrow).

As shown in FIG. 8, when the operation mode of the hydraulic crimping tool 100 is switched to the return operation s4 by the operation of the tool operating tool 100c, or when the detected value of the pressure sensor 14 reaches the main pressure reference value. The control device 31 moves the spool position of the preload switching valve 17 to the position II in which the low pressure oil passage 18 and the preload oil passage 19 are connected to the hydraulic oil tank 30. At the same time, the control device 31 sets the spool position of the main pressure switching valve 24 to the I position where the pressure reducing oil passage 25 is connected to the discharge oil passage 20 and the pressure increasing oil passage 26 is connected to the hydraulic oil tank 30. Move. That is, the pressure boosting device 12 increases the volume of the pressure boosting chamber 13a of the pressure boosting cylinder 13 to reduce the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a, and opens the pilot check valve 27 to increase the pressure chamber. The hydraulic oil in 13a and the hydraulic oil in the hydraulic crimping tool 100 are discharged to the hydraulic oil tank 30 (see the light ink portion). As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved in the direction away from the receiving portion 100b, and the sleeve S is released from the movable portion 100a and the receiving portion 100b (see the black arrow).

Further, when the hydraulic pressure switching operation tool 11a of the aerial work platform 1 is operated, the control device 31 sets the spool position of the preload switching valve 17 to the low pressure oil passage 18 and the preload oil regardless of the detected value of the pressure sensor 14. The road 19 is moved to the II position where it is connected to the hydraulic oil tank 30. At the same time, the control device 31 sets the spool position of the main pressure switching valve 24 to the I position where the pressure reducing oil passage 25 is connected to the discharge oil passage 20 and the pressure increasing oil passage 26 is connected to the hydraulic oil tank 30. Move. That is, the pressure boosting device 12 increases the volume of the pressure boosting chamber 13a to reduce the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a, and opens the pilot check valve 27 to open the hydraulic oil in the pressure boosting chamber 13a. And the hydraulic oil in the hydraulic crimping tool 100 are discharged to the hydraulic oil tank 30. As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved in the direction away from the receiving portion 100b, and the sleeve S is released from the movable portion 100a and the receiving portion 100b.

With this configuration, when the pressure booster 12 controls the hydraulic pressure of the hydraulic oil at the time of the temporary holding operation s1 by the relief valve 21, the low pressure oil passage 18 is operated without providing the directional control valve for the relief valve 21. The hydraulic oil is supplied with only the oil flow rate limited to the relief flow rate or less. That is, the pressure boosting device 12 does not limit the flow rate of the hydraulic oil supplied to the pressure boosting cylinder 13 through the pressure boosting oil passage 26 during this compression operation. Therefore, in the hydraulic crimping tool 100, the speed at the time of this compression operation is not affected by the relief flow rate of the relief valve 21. Further, the pressure booster 12 switches between the preload switching valve 17 and the main pressure switching valve 24 based on at least one signal of the operation signal from the hydraulic crimping tool 100 and the detected value of the pressure sensor 14. .. That is, the pressure booster 12 can selectively supply the hydraulic oil of low pressure or preload to the supply oil passage 15 at different flow rates. As a result, the pressure booster 12 can supply the hydraulic oil to the hydraulic tool without limiting the flow rate of the hydraulic oil at the time of pressure boosting without providing a directional control valve for hydraulic pressure switching.

As shown in FIGS. 3 and 9, when the hydraulic crimping tool 100 is provided with the tool-side pressure sensor 100d, the tool-side pressure is provided as another embodiment of the pressure booster 12 for aerial work platforms. The configuration may be such that the detection value of the sensor 100d is acquired to control the preload switching valve 17 and the main pressure switching valve 24. The pressure booster 12 is configured so that the control device 31 can acquire the detected value of the tool-side pressure sensor 100d via the connector 31a which is the hydraulic pressure acquisition means.

With this configuration, the pressure booster 12 has a pressure loss and a change in oil temperature that occur while the hydraulic oil boosted by the pressure boosting cylinder 13 is supplied to the hydraulic crimping tool 100 through the supply oil passage 15. The detection value that takes into account the effect of Therefore, the pressure boosting device 12 manages the hydraulic pressure and the oil temperature of the operating oil with higher accuracy than the detection value of the pressure sensor 14 provided in the pressure boosting chamber 13a of the pressure boosting cylinder 13, and together with the preload switching valve 17. The main pressure switching valve 24 can be controlled. Further, the pressure booster 12 can perform correction and failure diagnosis between the pressure sensor 14 and the tool side pressure sensor 100d by comparing the detected value of the pressure sensor 14 with the detected value of the tool side pressure sensor 100d. ..

Next, with reference to FIGS. 2 to 8, 10, and 11, the operation mode of the pressure booster 12 in the caulking work of the sleeve S for electrical wiring by the hydraulic crimping tool 100 will be described. In the present embodiment, it is assumed that the hydraulic crimping tool 100 is connected to the joint 16 in the pressure booster 12.

As shown in FIG. 2, when the tool operating tool 100c is not operated and the operating mode of the hydraulic crimping tool 100 is switched to the stopped state, the control device 31 sets the spool position of the preload switching valve 17 to the preload oil passage. 19 is moved to the II position where it is connected to the hydraulic oil tank 30. At the same time, the control device 31 moves the spool position of the main pressure switching valve 24 to the position II in which the pressure reducing oil passage 25 and the pressure increasing oil passage 26 are connected to the hydraulic oil tank 30. That is, the pressure booster 12 does not supply hydraulic oil to the hydraulic crimping tool 100. As a result, the hydraulic crimping tool 100 is stopped in a state where the movable portion 100a is separated from the receiving portion 100b (a state in which the sleeve S is released).

As shown in FIGS. 5 and 10, when the operation mode of the hydraulic crimping tool 100 is switched to the temporary holding operation s1 by the operation of the tool operating tool 100c, the control device 31 moves the spool position of the preload switching valve 17. Is moved to the I position where the preload oil passage 19 is connected to the hydraulic oil tank 30. At the same time, the control device 31 moves the spool position of the main pressure switching valve 24 to the position II in which the pressure reducing oil passage 25 and the pressure increasing oil passage 26 are connected to the hydraulic oil tank 30 (see step S110). ..

When the detected value of the pressure sensor 14 is less than the low pressure reference value lower than the preload, the control device 31 sets the spool position of the preload switching valve 17 to the I position in which the preload oil passage 19 is connected to the discharge oil passage 20. (See step S120). When the detected value of the pressure sensor 14 reaches the low pressure reference value, the control device 31 moves the spool position of the preload switching valve 13 to the position II in which the preload oil passage 19 is connected to the hydraulic oil tank 30. (See step S130). At this time, the pressure booster 12 maintains the hydraulic oil in the pressure boosting chamber 13a of the pressure boosting cylinder 13 and in the hydraulic crimping tool 100 by the action of the check valve 23, and maintains the hydraulic pressure at the low pressure reference value. .. That is, the pressure booster 12 supplies the hydraulic oil to the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100 until the hydraulic pressure of the hydraulic oil reaches the low pressure reference value. As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved toward the receiving portion 100b, and the sleeve S is gripped by the movable portion 100a and the receiving portion 100b. At the same time, the pressure booster 12 discharges air in the pressure boosting chamber 13a, the hydraulic crimping tool 100, and the supply oil passage 15 by supplying low-pressure hydraulic oil.

As shown in FIGS. 6 and 10, when the operation mode of the hydraulic crimping tool 100 is switched to the present compression operation by the operation of the tool operating tool 100c (see step S140), the control device 31 is a preload switching valve. The spool position of 17 is moved to the position III in which the preload oil passage 19 is connected to the discharge oil passage 20. At the same time, the control device 31 moves the spool position of the main pressure switching valve 24 to the position II in which the pressure reducing oil passage 25 and the pressure increasing oil passage 26 are connected to the hydraulic oil tank 30 (see step S150). ..

When the detected value of the pressure sensor 14 is less than the preload reference value which is the discharge pressure of the hydraulic pump 28, the control device 31 is in a state where the preload oil passage 19 is connected to the discharge oil passage 20 at the spool position of the preload switching valve 17. It is held at the position III (see step S160). When the detection value of the pressure sensor 14 reaches the preload reference value, the control device 31 moves the spool position of the preload switching valve 17 to the position II in which the preload oil passage 19 is connected to the hydraulic oil tank 30. (See step S170). At this time, the pressure booster 12 preloads the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic pressure of the hydraulic oil in the hydraulic crimping tool 100 by the action of the check valve 23 of the preload oil passage 19. Maintain the standard value. That is, the pressure booster 12 supplies the hydraulic oil to the pressure boosting chamber 13a of the pressure boosting cylinder 13 and the hydraulic crimping tool 100 until the hydraulic pressure of the hydraulic oil reaches the preload reference value. As a result, in the hydraulic crimping tool 100, as the preload step s2 of the main compression operation, the movable portion 100a is pressed by the hydraulic oil of the preload that has not been increased by a predetermined force to apply the preload to the sleeve S. At the same time, the pressure booster 12 discharges the air in the pressure boosting chamber 13a, the hydraulic crimping tool 100, and the supply oil passage 15 by supplying the hydraulic oil of the preload.

As shown in FIGS. 7 and 10, when the detected value of the pressure sensor 14 reaches the preload reference value in the preload step s2 of this compression operation, the control device 31 sets the spool position of the preload switching valve 17 to low pressure oil. The passage 18 and the preload oil passage 19 are moved to the II position where they are connected to the hydraulic oil tank 30. At the same time, the control device 31 sets the spool position of the main pressure switching valve 24 to the position III in which the boosting oil passage 26 is connected to the discharge oil passage 20 and the pressure reducing oil passage 25 is connected to the hydraulic oil tank 30. Move (see step S170). The pressure boosting device 12 reduces the volume of the pressure boosting chamber 13a by the pressure boosting cylinder 13 to increase the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a. As a result, in the hydraulic crimping tool 100, as the main pressure step s3 of the main compression operation, the movable portion 100a is pressed by the hydraulic oil boosted by the pressure boosting cylinder 13 with a predetermined force to crimp the sleeve S.

As shown in FIGS. 8 and 11, when the operation mode of the hydraulic crimping tool 100 is switched to the return operation s4 by the operation of the tool operating tool 100c, or the detected value of the pressure sensor 14 becomes the main pressure reference value. When it reaches (see step S180), the control device 31 moves the spool position of the preload switching valve 17 to the position II in which the preload oil passage 19 is connected to the hydraulic oil tank 30. At the same time, the control device 31 sets the spool position of the main pressure switching valve 24 to the I position where the pressure reducing oil passage 25 is connected to the discharge oil passage 20 and the pressure increasing oil passage 26 is connected to the hydraulic oil tank 30. Move (see step S190). The pressure boosting device 12 increases the volume of the pressure boosting chamber 13a by the pressure boosting cylinder 13 to reduce the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a, and opens the pilot check valve 27 to enter the pressure boosting chamber 13a. And the hydraulic oil in the hydraulic crimping tool 100 is discharged to the hydraulic oil tank 30. As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved in the direction away from the receiving portion 100b, and the sleeve S is released from the movable portion 100a and the receiving portion 100b.

Further, as shown in FIG. 11, when the detected value of the pressure sensor 14 does not reach the main pressure reference value in step S180, the hydraulic oil is passed through the pressure boosting oil passage 26 into the rod side oil chamber 13c of the pressure boosting cylinder 13. It is determined whether or not the time from the start of the supply of the above time exceeds a predetermined time (see step S185). If the time from the start of supplying hydraulic oil exceeds a predetermined time, the pressure can be increased to the main pressure reference value due to some failure in the pressure sensor 14 or gas mixed in the pressure booster 12. Assuming that there was not, the control device 31 connects the spool position of the main pressure switching valve 24 to the pressure reducing oil passage 25 to the discharge oil passage 20 and the pressure increasing oil passage 26 to the hydraulic oil tank 30. (See step S190). The pressure boosting device 12 increases the volume of the pressure boosting chamber 13a by the pressure boosting cylinder 13 to reduce the hydraulic pressure in the pressure boosting chamber 13a, and opens the pilot check valve 27 to hydraulically crimp the pressure inside the pressure boosting chamber 13a. The hydraulic oil in the tool 100 is discharged to the hydraulic oil tank 30. As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved in the direction away from the receiving portion 100b, and the sleeve S is released from the movable portion 100a and the receiving portion 100b.

Further, as shown in FIG. 12, when the hydraulic crimping tool 100 is provided with the tool side pressure sensor 100d in the process after step S180, as another embodiment of the pressure booster 12 for a high-altitude work vehicle, The preload switching valve 17 and the main pressure switching valve 24 may be controlled by the difference between the detected value of the tool-side pressure sensor 100d and the detected value of the pressure sensor 14.

In step S180, when the detected value of the pressure sensor 14 does not reach the main pressure reference value, whether or not the difference between the detected value of the tool-side pressure sensor 100d and the detected value of the pressure sensor 14 is equal to or greater than a predetermined value. Determine (see step S181). When the difference between the detection value of the tool-side pressure sensor 100d and the detection value of the pressure sensor 14 is equal to or greater than a predetermined value, the control device 31 sets the spool position of the main pressure switching valve 24 so that the pressure reducing oil passage 25 becomes the discharge oil passage 20. The pressure increasing oil passage 26 is moved to the I position, which is connected and connected to the hydraulic oil tank 30 (see step S190).

When the difference between the detected value of the tool-side pressure sensor 100d and the detected value of the pressure sensor 14 is less than a predetermined value, the hydraulic oil is started to be supplied to the rod-side oil chamber 13c of the pressure boosting cylinder 13 through the pressure boosting oil passage 26. It is determined whether or not the time since then exceeds the predetermined time (see step S185). If the time from the start of supplying hydraulic oil exceeds a predetermined time, the pressure can be increased to the main pressure reference value due to some failure in the pressure sensor 14 or gas mixed in the pressure booster 12. Assuming that there was not, the control device 31 connects the spool position of the main pressure switching valve 24 to the pressure reducing oil passage 25 to the discharge oil passage 20 and the pressure increasing oil passage 26 to the hydraulic oil tank 30. (See step S190). The pressure boosting device 12 increases the volume of the pressure boosting chamber 13a by the pressure boosting cylinder 13 to reduce the hydraulic pressure in the pressure boosting chamber 13a, and opens the pilot check valve 27 to hydraulically crimp the pressure inside the pressure boosting chamber 13a. The hydraulic oil in the tool 100 is discharged to the hydraulic oil tank 30. As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved in the direction away from the receiving portion 100b, and the sleeve S is released from the movable portion 100a and the receiving portion 100b.

With this configuration, the pressure booster 12 is located between the pressure sensor 14 provided in the pressure boost chamber 13a of the pressure booster cylinder 13 and the tool-side pressure sensor 100d provided in the hydraulic crimping tool 100. When the difference is larger than a predetermined value, it is assumed that the pressure cannot be increased to the main pressure reference value due to some failure in the pressure sensor 14 or gas mixed in the pressure increasing device 12, and the pressure is increased in the pressure increasing cylinder 13a. The hydraulic pressure can be reduced and the pilot check valve 27 can be opened to discharge the hydraulic oil in the pressure boosting chamber 13a and the hydraulic crimping tool 100 to the hydraulic oil tank 30.

Further, as shown in FIG. 13, in the processing after step S180, the time from the start of supplying the hydraulic oil to the rod side oil chamber 13c of the pressure boosting cylinder 13 through the pressure boosting oil passage 26 exceeds a predetermined time. In this case, the hydraulic oil may be discharged to the hydraulic oil tank 30, and the warning means 33 may be used to warn of an abnormality.

When the detected value of the pressure sensor 14 does not reach the main pressure reference value, the time from the start of supplying the hydraulic oil to the rod side oil chamber 13c of the pressure boosting cylinder 13 through the pressure boosting oil passage 26 is a predetermined time. It is determined whether or not the pressure has been exceeded (see step S185). If the time from the start of supplying hydraulic oil exceeds a predetermined time, the pressure can be increased to the main pressure reference value due to some failure in the pressure sensor 14 or gas mixed in the pressure booster 12. Assuming that there was not, the control device 31 connects the spool position of the main pressure switching valve 24 to the pressure reducing oil passage 25 to the discharge oil passage 20 and the pressure increasing oil passage 26 to the hydraulic oil tank 30. (See step S200). Further, the warning means 33 warns that an abnormality has occurred.

With this configuration, the pressure booster 12 may not be able to boost the pressure to the main pressure reference value, and the main pressure step s3 of the main compression operation may not be performed normally. Can be warned.

Further, in the processing after step S180, when the difference between the detected value of the tool-side pressure sensor 100d and the detected value of the pressure sensor 14 is equal to or more than a predetermined value, and the rod-side oil chamber 13c of the pressure boosting cylinder 13 is used. When the time from the start of supplying the hydraulic oil through the pressure boosting oil passage 26 exceeds a predetermined time, the hydraulic oil is discharged to the hydraulic oil tank 30 and an abnormality is warned by the warning means 33. May be.

As shown in FIG. 14, when the detected value of the pressure sensor 14 does not reach the main pressure reference value, is the difference between the detected value of the tool side pressure sensor 100d and the detected value of the pressure sensor 14 equal to or more than a predetermined value? It is determined whether or not (see step S181). When the difference between the detected value of the tool-side pressure sensor 100d and the detected value of the pressure sensor 14 is equal to or greater than a predetermined value, the pressure boosting oil passage 26 is moved to the I position where it is connected to the hydraulic oil tank 30 (step). See S200). Further, the warning means 33 warns that an abnormality has occurred (see step S201).

When the difference between the detected value of the tool-side pressure sensor 100d and the detected value of the pressure sensor 14 is less than a predetermined value, the hydraulic oil is started to be supplied to the rod-side oil chamber 13c of the pressure boosting cylinder 13 through the pressure boosting oil passage 26. It is determined whether or not the time since then exceeds the predetermined time (see step S185). If the time from the start of supplying hydraulic oil exceeds a predetermined time, the pressure can be increased to the main pressure reference value due to some failure in the pressure sensor 14 or gas mixed in the pressure booster 12. Assuming that there was not, the control device 31 connects the spool position of the main pressure switching valve 24 to the pressure reducing oil passage 25 to the discharge oil passage 20 and the pressure increasing oil passage 26 to the hydraulic oil tank 30. (See step S200). Further, the warning means 33 warns that an abnormality has occurred (see step S201).

With this configuration, the pressure booster 12 may not be able to boost the pressure to the main pressure reference value, and the main pressure step s3 of the main compression operation may not be performed normally. Can be warned.

Further, when performing the work a plurality of times, in step S185, the predetermined time may be set to a second predetermined time shorter than the normal predetermined time.
With this configuration, if the detected value of the pressure sensor 14 cannot be increased to the main pressure reference value multiple times, there is a high possibility that some kind of failure has occurred in the pressure sensor 14, so the main pressure step s3 is performed. Since it can be rounded up early, wasteful work time can be shortened and maintenance time can be secured.

Further, when the hydraulic pressure switching operation tool 11a of the aerial work platform 1 is operated, the control device 31 sets the spool position of the preload switching valve 17 to the hydraulic oil in the preload oil passage 19 regardless of the value detected by the pressure sensor 14. Move to position II, which is connected to the tank 30. At the same time, the control device 31 sets the spool position of the main pressure switching valve 24 to the I position where the pressure reducing oil passage 25 is connected to the discharge oil passage 20 and the pressure increasing oil passage 26 is connected to the hydraulic oil tank 30. Move. The pressure boosting device 12 increases the volume of the pressure boosting chamber 13a by the pressure boosting cylinder 13 to reduce the hydraulic pressure of the hydraulic oil in the pressure boosting chamber 13a, and opens the pilot check valve 27 to enter the pressure boosting chamber 13a. And the hydraulic oil in the hydraulic crimping tool 100 is discharged to the hydraulic oil tank 30. As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved in the direction away from the receiving portion 100b, and the sleeve S is released from the movable portion 100a and the receiving portion 100b.

With this configuration, the pressure booster 12 needs to limit the flow rate of the hydraulic oil in the preload oil passage 19 by controlling the hydraulic pressure of the hydraulic oil at the time of the temporary holding operation s1 based on the detected value of the pressure sensor 14. There is no. That is, the pressure boosting device 12 does not limit the flow rate of the hydraulic oil supplied to the pressure boosting cylinder 13 through the pressure boosting oil passage 26 during this compression operation. As a result, the pressure booster 12 can supply the hydraulic oil to the hydraulic crimping tool 100 without limiting the flow rate of the hydraulic oil at the time of pressure boosting without providing a directional control valve for hydraulic pressure switching.

The case where the hydraulic crimping tool 100 is connected to the pressure booster 12 of the aerial work platform 1 has been described above, but the present invention is not limited to the hydraulic crimping tool 100, and the hydraulic tool that can be attached to and detached from the pressure booster 12 It should be. The above-described embodiment only shows a typical embodiment, and can be variously modified and implemented within a range that does not deviate from the gist of one embodiment. It goes without saying that it can be carried out in various forms, and the scope of the present invention is indicated by the description of the claims, and further, the equal meaning described in the claims, and all within the scope. Including changes.

1 Aerial work platform 13 Pressure boosting cylinder 13a Pressure boosting chamber 15 Supply oil passage 17 Preload switching valve 18 Low pressure oil passage 19 Preload oil passage 21 Relief valve 25 Decompression oil passage 26 Pressure boosting oil passage 33 Warning means

Claims (4)

A pressure booster for aerial work platforms that supplies hydraulic oil boosted by a pressure boost cylinder to hydraulic tools.
A supply oil passage connecting the pressure boosting chamber of the pressure boosting cylinder and the hydraulic tool, and
An electromagnetic switching valve for preload connected to the supply oil passage,
It is provided with an electromagnetic switching valve for main pressure connected to the pressure boosting cylinder.
The electromagnetic switching valve for preload and the electromagnetic switching valve for main pressure are connected in parallel to the hydraulic source.
The preload electromagnetic switching valve is configured to be selectively switchable between a state in which hydraulic oil is supplied to the supply oil passage through the preload oil passage and a state in which hydraulic oil is not supplied to the supply oil passage.
The electromagnetic switching valve for main pressure supplies hydraulic oil to the head side oil chamber of the pressure boosting cylinder through a pressure boosting oil passage, and supplies hydraulic oil to the rod side oil chamber of the pressure boosting cylinder through a decompression oil passage. It is configured to be selectively switchable between the state of
A pressure sensor is provided in the pressure boosting chamber of the pressure boosting cylinder.
When the detection value of the pressure sensor reaches the preload reference value while the electromagnetic switching valve for preload is switched to the state of supplying hydraulic oil to the supply oil passage through the preload oil passage, the preload The electromagnetic switching valve for main pressure is switched to a state in which hydraulic oil is not supplied, and the electromagnetic switching valve for main pressure is switched to a state in which hydraulic oil is supplied to the oil chamber on the head side of the boosting cylinder through the boosting oil passage.
When the electromagnetic switching valve for main pressure is switched to a state in which hydraulic oil is supplied to the oil chamber on the head side of the pressure boosting cylinder through the pressure boosting oil passage, the detected value of the pressure sensor is the main pressure reference value. When the pressure reaches, the electromagnetic switching valve for the main pressure is switched to a state in which hydraulic oil is supplied to the rod side oil chamber of the boosting cylinder through the pressure reducing oil passage.
When the electromagnetic switching valve for main pressure is switched to a state in which hydraulic oil is supplied to the oil chamber on the head side of the pressure boosting cylinder through the pressure boosting oil passage, the detected value of the pressure sensor is the main pressure reference value. When the time from the start of supplying hydraulic oil to the head side oil chamber of the booster cylinder through the booster oil passage exceeds a predetermined time, the electromagnetic switching valve for the main pressure Is a pressure booster for high-altitude work vehicles that is switched to a state in which hydraulic oil is supplied to the rod side oil chamber of the pressure boost cylinder through the decompression oil passage. The hydraulic tool is provided with a tool-side pressure sensor .
When the electromagnetic switching valve for the main pressure is switched to a state in which hydraulic oil is supplied to the oil chamber on the head side of the boosting cylinder through the boosting oil passage, the detection value of the pressure sensor and the tool side. When the difference from the detection value of the pressure sensor is equal to or more than a predetermined value, or when the difference between the detection value of the pressure sensor and the detection value of the tool-side pressure sensor is less than the predetermined value, the increase When the time from the start of supplying hydraulic oil to the oil chamber on the head side of the pressure cylinder through the pressure boosting oil passage exceeds a predetermined time, the electromagnetic switching valve for the main pressure is activated in the rod side oil chamber of the pressure boost cylinder. The pressure booster for an aerial work vehicle according to claim 1, wherein the pressure booster is switched to a state in which hydraulic oil is supplied through the decompression oil passage. Warning means are provided to warn of abnormalities,
Claim 1 or claim that when the electromagnetic switching valve for main pressure is switched to a state in which hydraulic oil is supplied to the rod side oil chamber of the pressure boosting cylinder through the pressure reducing oil passage, an abnormality is warned by the warning means. 2. The pressure booster for aerial work platforms according to 2. The electromagnetic switching valve for the main pressure is switched to a state in which hydraulic oil is supplied to the rod-side oil chamber of the boosting cylinder through the decompression oil passage.
Again, when the electromagnetic switching valve for the main pressure is switched to a state where hydraulic oil is supplied to the oil chamber on the head side of the pressure boosting cylinder through the pressure boosting oil passage, the detected value of the pressure sensor is the main pressure. If the reference value is not reached and the time from the start of supplying hydraulic oil to the head side oil chamber of the booster cylinder through the booster oil passage exceeds the second predetermined time, the present The electromagnetic switching valve for pressure is switched to a state in which hydraulic oil is supplied to the rod side oil chamber of the boosting cylinder through the decompression oil passage.
The pressure booster for an aerial work platform according to any one of claims 1 to 3, wherein the second predetermined time is set to be shorter than the predetermined time.

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