JP4225635B2 - Cabylt equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cabbutylt device mounted on a cabover engine type automobile, and more particularly, to a carbilt device for tilting a cab by a cylinder device, and to which a cab lowering prevention device for preventing the cab from descending is attached. About.
[0002]
[Prior art]
In medium- and large-sized cab-over type trucks, the maintenance and inspection of the engine portion can be easily performed by lifting and tilting the cab. In these vehicles, there is used a cabylt device configured such that a tilt cylinder device is interposed between a cab and a frame, and the tilt operation of the tilt cylinder device is performed to tilt the cab.
[0003]
In such a cabylt device, a cab lowering prevention device is provided for preventing the cab from lowering when a failure occurs in the tilt cylinder device. As the cab lowering prevention device, a stay having a plurality of teeth is pivotally attached to the upper end portion of the piston rod of the tilt cylinder device, and a lowering prevention member is pivotally attached to the cylinder of the tilt cylinder device. Some are configured to prevent the piston rod from being shortened by the weight of the cab when the member is engaged with the stay.
[0004]
In the cab lowering prevention device, when the cab is tilted down after the lowering is prevented by the engagement of the lowering prevention member with the stay, it is necessary to release the engagement of the lowering prevention member with the stay in advance. is there. Therefore, in the conventional cab lowering prevention device, a release lever is connected to the lowering prevention member by a control cable, and the release lever is manually operated by an operator, thereby engaging the lowering prevention member with the stay. The connection is released via the control cable.
[0005]
[Problems to be solved by the invention]
However, the above-described cabylt device is configured such that the disengagement between the lowering prevention member and the stay is performed through the control cable by manual operation of the release lever. is there.
[0006]
Since the release lever is manually operated via the control cable, the hand becomes dirty and a relatively large force is required. If the release lever is not operated when the cab is lowered, or if the tilt cylinder device is shortened while the operation is incomplete, a failure may occur. Wiring work of the control cable for transmitting the operating force of the release lever to the lowering prevention member is required. Since it is necessary to arrange both the switching lever and the release lever in the switching valve of the tilt cylinder device at positions where they can be easily operated, the layout when mounted on an actual vehicle is restricted, resulting in an increase in cost.
[0007]
An object of the present invention is to provide a cabylt device capable of automatically releasing the engagement between the cab lowering prevention member and the stay.
[0008]
[Means for Solving the Problems]
  A cabylt device according to claim 1 of the present invention includes a tilt cylinder device that is interposed between a cab and a frame and tilts the cab, and a cab lowering prevention device that is assembled to the tilt cylinder device. The tilt cylinder device includes a raising-side supply / discharge oil passage connected to a cylinder-side hydraulic chamber of the cylinder, a lower-side supply / discharge oil passage connected to a cab-side hydraulic chamber of the cylinder, and the raising-side supply / discharge oil passage. A switching valve that switches between the lower side oil supply and discharge passages, and the cab lowering prevention device has a stay pivotally attached to a piston rod of the tilt cylinder device and a cylinder of the tilt cylinder device. In a cabylt device provided with a descending prevention member supported and engaged with the stay,
  A release cylinder device for releasing the engagement of the lowering prevention member with the stay is installed in the cylinder of the tilt cylinder device,
  A release oil passage and a communication oil passage are connected to the cylinder chamber of the release cylinder device, and the release oil passage constitutes a part of the lower-side supply / discharge oil passage and serves as one of the switching valves. The communication oil passage forms part of the lower-side supply / discharge oil passage and is connected to the cab-side hydraulic chamber of the tilt cylinder device.And
The release cylinder device is disposed so that the cylinder chamber extends radially outward with respect to the cylinder of the tilt cylinder device, and is fixed to the cylinder outer peripheral surface of the tilt cylinder device, The lowering prevention member is pivotally supported by a pin on a cylinder block of the release cylinder device in a state of straddling the release cylinder device, and a push portion of a plunger of the release cylinder device is lowered. Facing the opposing surface of the blocking member,It is characterized by that.
[0009]
  A carbitol device according to claim 2 of the present invention is:The communication oil passage is provided with an orifice for restricting the flow of pressure oil.It is characterized by that.
[0010]
  According to claim 3 of the present invention, there is providedAboveA pilot-operated check valve is installed in the flange-side supply / discharge oil passage.CommentThe removal cylinder device opens at the same time as or after releasing the engagement between the lowering prevention member and the stay.The pilot hydraulic pressure of the pilot operated check valve is setIt is characterized by being.
[0011]
According to the first means described above, the hydraulic pressure is applied to the cylinder chamber of the release cylinder device when the hydraulic pressure is applied to the lower side oil supply / discharge passage of the cylinder of the tilt cylinder device. Can be automatically disengaged from the stay by operating the lowering prevention member.
[0012]
  According to the second means described above,Since the pressure oil in the lower hydraulic chamber of the tilt cylinder device is gradually discharged by the throttle, the extension operation of the piston rod of the tilt cylinder device becomes slow, and the cab can be tilted up safely. Can do.
[0013]
According to the third means described above, since the engagement between the lowering prevention member and the stay is released before the tilt cylinder starts to descend, the cab can be smoothly lowered.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0015]
As shown in FIG. 1, the cabylt device according to the present embodiment includes a tilt cylinder device 3 that is interposed between the cab 1 and the frame 2 and that tilts the cab 1 by an expansion and contraction operation. That is, the upper end of the piston rod 4 of the tilt cylinder device 3 is pivotally attached to the cab 1, and the lower end of the cylinder 5 is pivotally attached to the frame 2.
[0016]
As shown in FIG. 2, the hydraulic drive circuit 10 of the tilt cylinder device 3 includes a raising-side supply / discharge oil passage (hereinafter, referred to as a raising-side oil passage) 11 and a lower-side supply / discharge oil passage (hereinafter, referred to as “up-side supply / discharge oil passage”). (Referred to as a lower oil passage) 12, a pump 13 driven by the motor 8, a tank 14, and a manual switching valve (hereinafter referred to as a switching valve) 15. The raising side oil passage 11 is fluidly connected to a frame side hydraulic chamber (hereinafter referred to as raising side hydraulic chamber) 5 a of the cylinder 5, and the lowering side oil passage 12 is connected to the cab side hydraulic chamber (hereinafter referred to as lowering portion) of the cylinder 5. Side hydraulic chamber) fluidly connected to 5b.
[0017]
The switching valve 15 is configured as a four-port / two-position / manually operated switching valve. In normal operation, the load port a of the raising side oil passage 11 is set to the tank port T and the loading port b of the lowering side oil passage 12 is set. Are connected to the pump port P, and at the time of switching, the load port a of the upside oil passage 11 is connected to the pump port P, and the load port b of the downside oil passage 12 is connected to the tank port T. ing. The raising side oil passage 11 is provided with check valves 16 each constituted by a pilot operated check valve. When the hydraulic pressure is less than a preset pilot pressure value, the check valve 16 is on the cylinder 5 side. To the switching valve 15 side, and the flow is allowed when the pilot pressure value is exceeded. In FIG. 2, 7 is an emergency manual pump, 9 is a relief valve, 17 is a throttle, 18 is a filter, and 19 is a check valve.
[0018]
As shown in FIG. 3, the cab lowering device is provided with a cab lowering prevention device 20 constituted by a stay and a lowering prevention member. That is, the stay 21 is formed in a long channel steel rod using a rigid metal material, and the upper end is pivotally attached to the upper end of the piston rod 4 of the tilt cylinder device 3. A plurality of teeth 22 are formed in a sawtooth shape at the intermediate portion at the opening side end of the stay 21. The teeth 22 are formed in a substantially half trapezoidal shape in which the lower side (frame side) is inclined and the upper side (cab side) is substantially perpendicular to the end side.
[0019]
A region of the outer peripheral surface of the cylinder 5 facing the stay 21 is covered and fixed with a protective cover 23 made of resin, and the protective cover 23 prevents the stay 21 and the cylinder 5 from rubbing against each other. It is like that. A channel-shaped yoke 24 is fixed to the cab side end of the cylinder 5 so as to straddle the cylinder 5. An appropriate clearance is provided between the inner surface of the yoke 24 and the protective cover 23 so as to allow the free end portion of the stay 21 to slide smoothly.
[0020]
As shown in FIGS. 3 and 4, a notch portion 25 for visually confirming that the teeth of the stay 21 and the claw portion 27 of the descending prevention member 26 are engaged with each other at the opening end side of the yoke 24. The channel-shaped steel-shaped descent prevention member 26 is disposed so as to face the notch 25. The lowering prevention member 26 is pivotally supported by a pin 28 in a state where the lowering prevention member 26 is fixed at a position opposite to the yoke 24 on the outer periphery of the cylinder 5 and straddles a cylinder block 31 of a release cylinder device 30 described later. A claw portion 27 is formed at the free end portion of the descending prevention member 26, and the claw portion 27 is configured to mesh with the lower end surface of the stay 21 and the teeth 22. The lowering prevention member 26 is provided with a locking portion 26a, and the yoke 24 is provided with a locking portion 24a. Between the locking portion 26a of the lowering prevention member 26 and the locking portion 24a of the yoke 24, The tension spring 29 is stretched in a power storage state. The tension spring 29 constantly urges the tension force in the direction in which the claw portion 27 of the descending prevention member 26 presses against the opening end side of the stay 21.
[0021]
As shown in FIGS. 5 and 6, a release cylinder device 30 for automatically releasing the lowering prevention member 26 is installed at a position opposite to the yoke 24 of the cylinder 5. That is, the release cylinder device 30 includes a cylinder block 31, and one main surface of the cylinder block 31 is fixed to the outer peripheral surface of the cylinder 5 of the tilt cylinder device 3.
[0022]
A cylinder chamber 32 is opened at the cab side end of the cylinder block 31 so as to extend radially outward with respect to the cylinder 5, and a cylinder head is formed at the opening of the cylinder chamber 32 on the side opposite to the cylinder 5. 33 is screwed. The rear end portion of the plunger 34 is accommodated in the cylinder chamber 32, the intermediate portion of the plunger 34 is slidably supported by the cylinder head 33, and the push portion 35 at the front end portion is connected to the cylinder 5 from the cylinder chamber 32. It protrudes in the opposite direction and faces the facing surface of the lowering prevention member 26. A return spring 36 is interposed between the cylinder head 33 and the plunger 34 so as to constantly urge the plunger 34 in the direction in which the plunger 34 is pulled. However, the return spring 36 is not always required in terms of function, and can be omitted as appropriate.
[0023]
A release oil passage 37 communicating with the cylinder chamber 32 is formed in the cylinder block 31. As shown in FIG. 2, the release oil passage 37 constitutes a part of the lower oil passage 12 and is connected to the load port b of the lower oil passage 12 of the switching valve 15. The cylinder chamber 32 is connected to one end of a communication oil passage 38 constituting a part of the lower oil passage 12, and the other end of the communication oil passage 38 is a lower oil pressure of the cylinder 5 of the tilt cylinder device 3. It is connected to the chamber 5b. An orifice 39 that restricts the flow of pressure oil is formed at the connection portion of the communication oil passage 38 of the cylinder 5.
[0024]
FIG. 7 is an electric circuit diagram of the motor 8 that drives the pump of the cabylt device, and shows a state in which the motor can run. As shown in FIG. 7, a control circuit 83 is interposed in the drive circuit 80 of the motor 8. That is, the switch 84a of the relay 84 of the control circuit 83 is provided in the middle of the drive circuit 80 in which the motor 8 and the power supply 81 are connected via the fuse 82, and the cab lock switch 85 is provided in the coil 84b of the relay 84. A stroke switch 86, a switching valve switch 87, a cab stopper switch 88, a transmission neutral detection switch (hereinafter referred to as neutral switch) 89, a thermal switch 90, a pump switch 91, a buzzer 92, and a fuse 93. And are connected.
[0025]
The cab switch 85 is arranged in a cab block device 94 (see FIG. 1) for locking the tilted cab, and detects that the cab 1 is locked by the cab block device 94. . As shown in FIG. 7, the cab lock switch 85 includes a fixed contact 85 a, a first contact 85 b, a second contact 85 c, and a movable iron piece 85 d, and the fixed contact 85 a is connected to the drive circuit 80 via a fuse 93. The first contact 85 b is connected to the switching valve switch 87, and the second contact 85 c is connected to the stroke switch 86. The cab switch 85 is configured such that the movable iron piece 85d is turned on to the second contact 85c only when the cab 1 is unlocked by the cab block device 94.
[0026]
The stroke switch 86 is constituted by a limit switch, and is installed in the tilt cylinder device 3 as shown in FIG. 3, and detects the state where the piston rod 4 of the tilt cylinder device 3 is shortened most. The operation of the motor 8, that is, the operation of the pump 13 is stopped. As shown in FIG. 7, the stroke switch 86 is connected in series between the second contact 85c of the cab lock switch 85 and the switching valve switch 87, and is turned off only when the piston rod 4 is shortened most. It is configured to be turned on at other times.
[0027]
The switching valve switch 87 is configured to detect a switching operation of the switching lever of the switching valve 15. That is, as shown in FIG. 8, a switching valve switch 87 for detecting the switching lever 15a is installed at the tilt-down side position of the switching valve 15. As shown in FIG. 7, the switching valve switch 87 includes a fixed contact 87 a, a first contact 87 b, a second contact 87 c, and a movable iron piece 87 d, and the fixed contact 87 a includes the stroke switch 86 and the cab switch 85. The first contact 87 b is connected to the cab stopper switch 88 in series, and the second contact 87 c is connected to the cab stopper switch 88 in parallel. The switching valve switch 87 is configured such that the movable iron piece 87d is turned on to the second contact 87c only when the switching valve 15 is switched to the tilt-down side.
[0028]
The cab stopper switch 88 is constituted by a limit switch, and is arranged on the cab lowering prevention device 20 as shown in FIGS. 3 and 4. As shown in FIG. Is detected to be prevented from being lowered by the cab lowering prevention device 20. As shown in FIG. 7, the cab stopper switch 88 is connected in series to the first contact 87 b of the switching valve switch 87 and is turned off when the cab 1 is prevented from being lowered by the cab lowering prevention device 20. When the prevention of lowering is released by the release cylinder device 30, it is configured to be turned on.
[0029]
The neutral switch 89 is connected to the first contact 87b of the switching valve switch 87 via the cab stopper switch 88 and directly connected to the second contact 87c of the switching valve switch 87, and only when the transmission is in the neutral position. It is configured to turn on and turn off at other times. The thermal switch 90 is connected in series between the neutral switch 89 and the pump switch 91, and is configured to be turned off only when overheating of the motor 8 is detected, and to be turned on at other times. The pump switch 91 is connected in series between the thermal switch 90 and the relay coil 84b, and is configured to be pressed by a hand to be turned on when the motor 8 is driven while being always off. The buzzer 92 is connected between the neutral switch 89 and the thermal switch 90.
[0030]
Next, the operation will be described.
[0031]
When the driver tries to tilt up the cab 1, first, the switching valve 15 is switched to the tilt-up side. When the pump switch 91 is turned on and the motor 8 rotates to drive the pump 13, the pressure oil of the pump 13 is pumped to the load port a of the raising side oil passage 11 by the switching valve 15 in FIG. . The pressure oil pressure-fed to the load port a of the raising side oil passage 11 flows into the raising side hydraulic chamber 5a of the cylinder 5 of the tilt cylinder device 3 through the check valve 16, and the piston rod 4 is extended to operate the cab. 1 is lifted from frame 2 and tilted up.
[0032]
At this time, in order to extend the piston rod 4, it is necessary to discharge the pressure oil in the lower hydraulic chamber 5 b of the cylinder 5. In this embodiment, in FIG. 2, the pressure oil in the lower hydraulic chamber 5 b of the cylinder 5 is the communication oil passage 38, the cylinder chamber 32 of the release cylinder device 30, the release oil passage 37, and the lower oil of the switching valve 15. It is discharged to the tank 14 via the load port b of the path 12. Therefore, the piston rod 4 of the tilt cylinder device 3 can be extended to tilt the cab 1 up.
[0033]
At this time, since the pressure oil in the lower hydraulic chamber 5b of the cylinder 5 is gradually discharged by the throttle 39, the extension operation of the piston rod 4 of the tilt cylinder device 3 is moderated, and the cab 1 is made safe. Tilt up and go.
[0034]
As shown in FIG. 4A, when the tilt-up operation is performed, the claw portion 27 of the lowering prevention member 26 of the cab lowering prevention device 20 is pressed against the teeth 22 of the stay 21 by the elastic force of the tension spring 29. Go sliding while being. That is, since the teeth 22 are formed in a semi-trapezoidal shape with a lower slope, the claw portion 27 slides without engaging with the teeth 22. That is, the tilt cylinder device 3 can tilt up the cab 1 without being obstructed by the cab lowering prevention device 20.
[0035]
As described above, the cab 1 is tilted up by the extension operation of the piston rod 4 of the tilt cylinder device 3, and as shown in FIG. 4B, the lower end surface of the stay 21 is lowered. When the height of the claw portion 27 is reached, the lowering prevention member 26 is pulled by the tension spring 29, whereby the claw portion 27 is engaged with the lower end surface of the stay 21. Since the stay 21 is mechanically locked by the engagement of the claw portion 27 of the lowering prevention member 26 with the lower end surface of the stay 21, the piston rod 4 to which the upper end of the stay 21 is fixed is surely lowered. It is in a prevented state.
[0036]
As shown in FIG. 4B, when the claw portion 27 of the lowering prevention member 26 is engaged with the lower end surface of the stay 21, the lever 88 a protruding from the lowering prevention member 26 is moved to the cab stopper switch 88. Press to turn it off. For this reason, in the electric circuit shown in FIG. 7, the relay coil 84b is demagnetized, the relay switch 84a is turned off, and the drive of the pump 13 by the motor 8 is automatically stopped.
[0037]
In the present embodiment, as shown in FIG. 2, the release oil passage 37 of the release cylinder device 30 is connected to the load port b of the lower side oil passage 12 of the switching valve 15. The pressure in the lower hydraulic chamber 5b of the cylinder device 3 gradually decreases after the pump 13 stops. For this reason, since the tension spring 29 also reduces the pressure in the cylinder chamber 32 of the release cylinder device 30, the lowering prevention member 26 can be rotated while pushing up the plunger 34 to engage the claw portion 27 with the stay 21. In addition, the cab stopper switch 88 can be turned off by the lever 88a.
[0038]
Thereafter, when the driver wants to tilt down the cab 1, first, the switching valve 15 is switched to the down side, and the pump switch 91 is turned on. Then, the pump 13 is driven by the motor 8, and the pressure oil of the pump 13 is pumped to the load port b of the lower side oil passage 12 by the switching valve 15. The pressure oil pressure-fed to the load port b of the lower side oil passage 12 enters the lower side hydraulic chamber 5b of the cylinder 5 of the tilt cylinder device 3 into the release oil passage 37, the cylinder chamber 32 of the release cylinder device 30, and the communication oil. The cab 1 is tilted down by flowing in via the path 38 and shortening the piston rod 4.
[0039]
At this time, in order to shorten the piston rod 4, it is necessary to discharge the pressure oil in the raising side hydraulic chamber 5 a of the cylinder 5. In the present embodiment, when the pressure in the lowering oil passage 12 becomes equal to or higher than the pilot pressure set in the check valve 16, the check valve 16 opens in FIG. The pressure oil is discharged to the tank 14 via the check valve 16 and the switching valve 15. Therefore, the piston rod 4 of the tilt cylinder device 3 can be shortened to tilt down the cab 1.
[0040]
  Incidentally, the pressure oil flowing through the check valve 16 from the cylinder 5 toward the tank 14 is throttled through the throttle 17 connected to the cylinder 5 side of the raising side oil passage 11 and the switching valve 15 side. The pressure oil in the raising side hydraulic chamber 5a is gradually discharged. Therefore, the piston rod 4 of the tilt cylinder device 3ShortenThe operation becomes gentle and the cab 1 can be tilted down safely.
[0041]
During the tilt-down operation described above, as shown in FIG. 4B, the claw portion 27 of the lowering prevention member 26 of the cab lowering prevention device 20 remains engaged with the lower end surface of the stay 21. The piston rod 4 of the tilt cylinder device 3 cannot be shortened. Therefore, in the present embodiment, before the piston rod 4 of the tilt cylinder device 3 starts to shorten, the release cylinder device 30 is operated to release the engagement of the lowering prevention member 26 with the stay 21. Has been. That is, when the switching valve 15 is switched to the tilt-down side, the pressure oil discharged from the pump 13 passes through the lowering oil passage 12, passes through the cylinder chamber 32, the communication oil passage 38, and the orifice 39 of the release cylinder device 30. It passes through and is supplied to the lower hydraulic chamber 5 b of the cylinder 5. The pressure oil supplied to the lower hydraulic chamber 5b acts to push the piston 4a downward. For this reason, the pressure oil in the raising side hydraulic chamber 5a tends to flow into the raising side oil passage 11, but cannot flow because it is blocked by the check valve 16. In this way, the pressure in the lower oil passage 12 rises and the pressure in the cylinder chamber 32 also rises. Therefore, as shown in FIG. 6, the plunger 34 is pushed out and the push portion 35 is moved down. Is pushed downward, the stay 21 and the claw 27 are disengaged. In this embodiment, the pressure oil in the lower oil passage 12 when the stay 21 and the lowering prevention member 26 are disengaged is used as the pilot oil pressure of the check valve 16 to open the check valve 16. I am doing so. In order to determine the valve opening pressure, the check valve opening pressure is designed by adjusting the diameter of the pilot piston, the spring constant of the spring that presses the pilot piston, the spring constant of the spring that presses the ball-shaped valve element, etc. The above adjustments are made.
[0042]
FIG. 9A shows the pilot operated check valve 16 employed in the present embodiment. In this pilot operated check valve 16, the pilot piston is made into a two-stage piston having a large-diameter portion and a small-diameter portion so that the check valve opens after the cylinder device 30 for releasing the valve opening pressure operates. By adjusting the diameter of the small-diameter portion in various ways, the valve opening pressure is made higher than that of the conventional pilot operated check valve shown in FIG. 9B.
[0043]
Even after the engagement is automatically released as described above, as long as the hydraulic pressure of the lower side oil passage 12 maintains the set value or more, the release cylinder device 30 is connected to the stay 21 of the lowering prevention member 26. The disengaged state is maintained. In other words, the tilt cylinder device 3 can tilt the cab 1 down without being obstructed by the cab lowering prevention device 20.
[0044]
By the way, in the case of the conventional example in which the cab lowering prevention device is released by manual operation, the cab stopper switch 88 can be forcibly returned to the original state by manual operation. However, when the cab lowering prevention device 20 is automatically released by the release cylinder device 30 as in the present embodiment, the cab stopper switch 88 is forcibly operated by manual operation of the cab lowering prevention device 20. Can not be restored.
[0045]
Therefore, in this embodiment, the switching valve switch 87 for detecting the switching operation is installed in the switching valve 15 as shown in FIG. 8, and the switching valve switch 87 is installed in the cab stopper switch 88 and the buzzer 92 in FIG. By connecting as shown, the cab stopper switch 88 can be automatically returned to the original ON state while maintaining safety.
[0046]
That is, in FIG. 8, when the switching lever 15a of the switching valve 15 is manually operated to the tilt-down position, the switching valve switch 87 is pushed by the switching lever 15a and automatically switched. The movable iron piece 87d of 87 is turned on to the second contact 87c. As a result, since the current is supplied to the buzzer 92 via the cab switch 85 → the switching valve switch 87 → the neutral switch 89, the buzzer 92 sounds. As the buzzer 92 sounds, it is warned that the cab 1 starts to be tilted down, so that safety is ensured.
[0047]
On the other hand, as described above, when the switching valve 15 is switched and the pump switch 91 is turned on, the lowering prevention member 26 is rotated against the tension spring 29 around the pin 28 by the plunger 34 of the release cylinder device 30. Therefore, the lever 88 a protruding from the descending prevention member 26 is automatically separated from the cab stopper switch 88. As a result, the closed cab stopper switch 88 automatically returns to the original ON state when not pressed.
[0048]
As described above, the cab 1 is tilted down, and when the cab 1 is lowered to a predetermined position and the latch is engaged with the lock pin of the cab block device 94, the piston rod 4 of the tilt cylinder device 3 is moved to the minimum shortening stroke. When the position is reached, in FIG. 7, the stroke switch 86 is automatically turned off. In addition, the movable iron piece 85d of the cab lock switch 85 is automatically switched to the first contact 85b side. When the lever 15a of the switching valve 15 is returned to the original position, the movable iron piece 87d of the switching valve switch 87 is turned on to the first contact 87b side. If the neutral switch 89 is turned off, the vehicle returns to the normal driving state shown in FIG.
[0049]
According to the embodiment, the following effects can be obtained.
[0050]
1) The cab lowering prevention operation can be released without manual operation of the release lever by providing a release cylinder device in the cab lowering prevention device that automatically releases the engagement of the lowering prevention member with the stay. In addition to simplifying the release operation, it is possible to prevent failure due to forgetting operation, and to increase the degree of freedom of layout when mounted on an actual vehicle.
[0051]
2) A selector valve switch that detects the switching operation is installed in the selector valve, and the selector valve switch is connected to the cab stopper switch and buzzer so that the selector valve switch is operated when the selector lever is manually operated to the tilt down position. Can automatically alarm that the cab starts to be tilted down by automatically sounding the buzzer, thereby improving the safety of the cabylt device.
[0052]
3) On the other hand, the lever that turns on the cab stopper switch is placed on the lowering prevention member that is turned against the tension spring by the plunger of the release cylinder device. Since it can be returned, automatic release of the cab lowering prevention device by the release cylinder device can be substantially realized.
[0053]
【The invention's effect】
As described above, according to the present invention, since the lowering prevention state of the cab lowering prevention device can be automatically released by the release cylinder device, it is possible to prevent a malfunction due to an erroneous operation, and to control the cable. This wiring work can be omitted.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a cab-over type vehicle equipped with a cabylt device according to an embodiment of the present invention.
FIG. 2 is a hydraulic circuit diagram of the carbylating device.
FIGS. 3A and 3B also show a cabylt device, in which FIG. 3A is a side view and FIG. 3B is a bottom view.
FIGS. 4A and 4B are side views showing the operation of the main part, where FIG. 4A shows before the lowering prevention and FIG. 4B shows the lowering prevention time.
FIG. 5 is an enlarged side sectional view showing a state in which a main part is prevented from descending;
FIG. 6 is an enlarged side cross-sectional view showing a state in which the lowering prevention is released.
FIG. 7 is a circuit diagram showing a motor drive circuit.
8A and 8B show the arrangement of the switching valve switch, where FIG. 8A is a front view and FIG. 8B is a side view.
FIG. 9 is a cross-sectional view showing a pilot operated check valve, where (a) shows an embodiment and (b) shows a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Cab, 2 ... Frame, 3 ... Cylinder apparatus for tilting, 4 ... Piston rod, 4a ... Piston, 5 ... Cylinder, 5a ... Frame side hydraulic chamber (raising side hydraulic chamber), 5b ... Cab side hydraulic chamber (lower side) Hydraulic chamber), 7 ... Manual pump, 8 ... Motor, 9 ... Relief valve, 10 ... Hydraulic drive circuit, 11 ... Up side supply / discharge oil passage (up side oil passage), 12 ... Down side supply / discharge oil passage (down side) Oil passage), 13 ... pump, 14 ... tank, 15 ... manual switching valve (switching valve), 15a ... switching lever, 16 ... check valve, 17 ... throttle, 18 ... filter, 19 ... check valve, 20 ... cab Lowering prevention device, 21 ... stay, 22 ... tooth, 23 ... protective cover, 24 ... yoke, 24a ... locking part, 25 ... notch part, 26 ... lowering prevention member, 26a ... locking part, 27 ... claw part, 28 ... Pin, 29 ... Tension spring, 30 ... Release cylinder device DESCRIPTION OF SYMBOLS 31 ... Cylinder block, 32 ... Cylinder chamber, 33 ... Cylinder head, 34 ... Plunger, 35 ... Push part, 36 ... Return spring, 37 ... Release oil path, 38 ... Communication oil path, 39 ... Orifice, 80 ... Motor drive Circuit, 81 ... Power supply, 82 ... Fuse, 83 ... Control circuit, 84 ... Relay, 84a ... Relay switch, 84b ... Relay coil, 85 ... Cabot switch, 85a, 87a ... Fixed contact, 85b, 87b ... First contact, 85c, 87c ... second contact, 85d, 87d ... movable iron piece, 86 ... stroke switch, 87 ... switch valve switch, 88 ... cab stopper switch, 88a ... lever, 89 ... transmission neutral detection switch (neutral switch), 90 ... thermal Switch 91 ... pump switch 92 ... buzzer, 3 ... fuse, 94 ... calibration block devices.

Claims (3)

A tilt cylinder device that is interposed between the cab and the frame and tilts the cab, and a cab lowering prevention device that is assembled to the tilt cylinder device. The tilt cylinder device is a cylinder-side hydraulic chamber of the cylinder. A switching valve that switches between the up-side supply / discharge oil passage connected to the cylinder, the down-side supply / discharge oil passage connected to the cab-side hydraulic chamber of the cylinder, and the up-side supply / discharge oil passage and the down-side supply / discharge oil passage The cab lowering prevention device includes a stay whose one end is pivotally attached to a piston rod of the tilt cylinder device, and a lowering prevention member supported by the cylinder of the tilt cylinder device and engaged with the stay. In a carbitol device comprising:
A release cylinder device for releasing the engagement of the lowering prevention member with the stay is installed in the cylinder of the tilt cylinder device,
A release oil passage and a communication oil passage are connected to the cylinder chamber of the release cylinder device, and the release oil passage constitutes a part of the lower-side supply / discharge oil passage and serves as one of the switching valves. The communication oil passage forms a part of the lower-side supply / discharge oil passage and is connected to the cab-side hydraulic chamber of the tilt cylinder device ,
The release cylinder device is disposed so that the cylinder chamber extends radially outward with respect to the cylinder of the tilt cylinder device, and is fixed to the cylinder outer peripheral surface of the tilt cylinder device, The lowering prevention member is pivotally supported by a pin on a cylinder block of the release cylinder device in a state of straddling the release cylinder device, and a push portion of a plunger of the release cylinder device is lowered. A cabylt device characterized by facing the opposing surface of the blocking member .   2. The carbitol device according to claim 1, wherein the communication oil passage is provided with a throttle for restricting a flow of pressure oil.   A pilot-operated check valve is interposed in the raising side oil supply / discharge passage, and is opened at the same time as or after the release cylinder device releases the engagement between the lowering prevention member and the stay. The cabylt device according to claim 1 or 2, wherein a pilot hydraulic pressure of the pilot operated check valve is set so as to be valved.

Images