JP7030596B2 - Power-assisted elevating device and how to use it - Google Patents

Description

The present invention relates to a power assist type elevating device capable of raising and lowering an object such as a suspended heavy object with a slight force and a method of using the same.

Conventionally, in factories that manufacture industrial products, various lifting devices have been used to suspend and lift objects such as heavy objects. Among them, a power assist type elevating device capable of elevating and lowering a suspended object with a slight force of an operator is known (see, for example, Patent Document 1).

The power-assisted elevating device disclosed in Patent Document 1 (referred to as "assisting device system" in the same document) includes a wire rope for suspending an object, a rotating drum for winding and winding the wire rope, and rotation. Two sets of motors for driving the drums are provided, and the rotating drums are rotated in the forward and reverse directions by the motors to raise and lower the object. This elevating device includes a force detecting means between the motor and the rotating drum, and the force detecting means detects the rotational torque to detect the weight of the object and the external force applied to the object. When the operator applies a vertical force to the suspended object, the elevating device detects the applied force by the force detecting means and generates an assist force to move the object in the same direction as the force. do.

Japanese Unexamined Patent Publication No. 2017-100814

However, in the elevating device of Patent Document 1, since the force applied by the operator to the object in the vertical direction is detected via the wire rope and the rotating drum, the slight force of the operator can be detected accurately and instantly. Is difficult. Therefore, it is difficult to generate the assist force desired by the operator in a timely manner, and good operability may not be obtained.

An object of the present invention is to provide a power assist type elevating device having excellent operability. As an example of a power assist type elevating device having excellent operability, a power assist type elevating device capable of generating an assist force desired by an operator in a timely manner can be mentioned.

The power assist type elevating device according to one aspect of the present invention is provided between an air cylinder that raises and lowers a suspended object by expanding and contracting, and the air cylinder and the object, and is connected below the air cylinder. It includes a load detector that detects the load of an object and a pneumatic control device that controls the supply of air pressure to the air cylinder. In the pneumatic control device, as air pressure supply control to the air cylinder, when the load detector detects a load within a range from a predetermined lower limit threshold value to a predetermined upper limit threshold value, the air pressure controller receives a load. Pneumatic pressure is supplied to the air cylinder so as to generate a predetermined first pulling force, and when the load detector detects a load exceeding the upper limit threshold, the air cylinder causes the first pulling force. Pneumatics are supplied to the air cylinder so as to generate a smaller predetermined second pulling force, and when the load detector detects a load less than the lower limit threshold, the air cylinder causes the first. Pneumatic pressure is supplied to the air cylinder so as to generate a predetermined third pulling force larger than the pulling force of.

According to the power assist type elevating device having such a configuration, the first pulling force, the second pulling force, the third pulling force, the lower limit threshold value and the upper limit threshold value are suitable for the weight of the object, respectively. A power-assisted elevating device with excellent operability can be obtained by setting the value to a threshold value. In particular, since the vertical force applied to the object by the operator is accurately and instantly detected by the load detector, the assist force desired by the operator can be generated in a timely manner.

Preferably, the pneumatic control device, when the load detector detects a load exceeding the upper limit threshold, until the load drops to a predetermined lower assist release threshold set to be equal to or lower than the upper limit threshold. During that time, the air pressure is supplied to the air cylinder so that the air cylinder generates the second pulling force, and when the load detector detects a load that does not reach the lower limit threshold, the load is said to be said. The air pressure is supplied to the air cylinder so that the air cylinder generates the third pulling force until the air cylinder rises to the predetermined upper assist release threshold value set to be equal to or higher than the lower limit threshold value.

Preferably, the pneumatic control device includes a pulling force setting means for setting the first pulling force, the second pulling force and the third pulling force by a predetermined operation, and the lower limit threshold value and the upper limit threshold value. It has a threshold value setting means for setting each of the above by a predetermined operation.

The method of using the power assist type elevating device according to one aspect of the present invention is the method of using the power assist type elevating device in a state where the object is suspended and no external force is applied to the object. The load detected by the load detector is defined as a reference load. Then, the pulling force setting means so that the downward load applied to the air cylinder when the load detector detects the reference load and the first pulling force generated by the air cylinder are balanced. Is used to set the first pulling force. Further, the pulling force setting means and the threshold setting so that the value obtained by subtracting the second pulling force from the first pulling force and the value obtained by subtracting the reference load from the upper limit threshold value are substantially the same. Means are used to set the second pulling force and the upper threshold. Further, the pulling force setting means and the threshold setting so that the value obtained by subtracting the first pulling force from the third pulling force and the value obtained by subtracting the lower limit threshold value from the reference load are substantially the same. Means are used to set the third pulling force and the lower threshold.

According to the method of using the power assist type elevating device, the value obtained by subtracting the second pulling force from the first pulling force and the value obtained by subtracting the reference load from the upper limit threshold are substantially the same. Since the value obtained by subtracting the first pulling force from the third pulling force and the value obtained by subtracting the lower limit threshold from the reference load are substantially the same, the operator moves up and down with respect to the object. Since the magnitude of the applied force and the magnitude of the assist force when the assist force is generated are substantially the same, the operator can smoothly move the object up and down.

According to the present invention, a power assist type elevating device having excellent operability can be obtained.

It is a figure which shows the power assist type elevating device which concerns on 1st Embodiment. It is a partial cross-sectional view which shows the load detection apparatus and its vicinity. It is a figure which shows the detail of the pneumatic control apparatus which concerns on 1st Embodiment. It is operation explanatory drawing at the time of moving an object downward by using the power assist type elevating apparatus which concerns on 1st Embodiment. It is operation explanatory drawing at the time of moving an object upward by using the power assist type elevating device which concerns on 1st Embodiment. It is a figure which shows the detail of the pneumatic control apparatus which concerns on 2nd Embodiment. It is a figure which shows the state when the object is suspended and stopped in the power assist type elevating device which concerns on 2nd Embodiment. It is operation explanatory drawing at the time of moving an object downward by using the power assist type elevating apparatus which concerns on 2nd Embodiment. It is operation explanatory drawing at the time of moving an object downward by using the power assist type elevating apparatus which concerns on 2nd Embodiment. It is an operation explanatory view at the time of stopping the downward assist after moving the object downward by using the power assist type elevating device which concerns on 2nd Embodiment. It is operation explanatory drawing at the time of moving an object upward by using the power assist type elevating device which concerns on 2nd Embodiment. It is operation explanatory drawing at the time of moving an object upward by using the power assist type elevating device which concerns on 2nd Embodiment. It is an operation explanatory view when the upward assist is stopped after moving an object upward by using the power assist type elevating device which concerns on 2nd Embodiment.

[First Embodiment]
Hereinafter, the power-assisted elevating device (hereinafter, simply referred to as “elevating device”) according to the first embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the elevating device 1 according to the present embodiment includes a slide frame 2, an air cylinder 3, a load detector 4, a load detection device 5, an operation device 6, a pneumatic control device 7, and the like.

The slide frame 2 is provided to suppress the runout of the piston rod 3a of the air cylinder 3 described later, and is composed of two guide shafts 9, an upper end horizontal member 10, a lower end horizontal member 11, and the like. .. The two guide shafts 9 are arranged in the vertical direction parallel to each other. Each guide shaft 9 is supported by a moving body 13 described later via two linear bearings 12. The upper end horizontal member 10 is erected on the upper end portion of the two guide shafts 9, and the lower end horizontal member 11 is erected on the lower end portion of the two guide shafts 9. In the present embodiment, a pair of guide rails 14 are erected in parallel at a predetermined height position of the building, and a traveling guide rail 18 extending in a direction perpendicular to the pair of guide rails 14 is erected so as to be movable. .. The moving body 13 is provided so as to be movable along the traveling guide rail 18.

The air cylinder 3 is supported by the moving body 13 in a state where the piston rod 3a is arranged on the lower side and the cylinder tube 3b is arranged on the upper side and the expansion and contraction direction is directed in the vertical direction. In this embodiment, the cylinder tube 3b of the air cylinder 3 is fixed to the moving body 13. The lower end of the piston rod 3a of the air cylinder 3 is fixed to the lower end horizontal member 11 of the slide frame 2. The cylinder tube 3b of the air cylinder 3 penetrates the through hole 10a formed in the upper end horizontal member 10 of the slide frame 2. That is, the slide frame 2 can move up and down with respect to the cylinder tube 3b. A brake unit 36 for preventing the fall is attached to the air cylinder 3 so that the object does not fall when the air leaks, the air runs out, or the like occurs in the air cylinder 3.

The load detector 4 is provided between the air cylinder 3 and the object to be moved up and down, and detects the load of the object connected below the load detector 4. The detected load is displayed on the load monitor 8 attached to the slide frame 2. In the present embodiment, the load detector 4 is connected to the lower part of the load detection device 5 fixed under the lower end horizontal member 11 via the connecting tool 15. Further, a hook 16 is connected below the load detector 4. The load detector 4 detects the load obtained by adding the weight of the hook 16 and the load applied to the hook 16. The magnitude of the load applied to the hook 16 is the sum of the weight of the sling hung on the hook 16, the weight of the suspended object, and the vertical external force applied to the object by the operator. .. When some member is interposed between the sling and the object, the weight of the member is naturally included in the load applied to the hook 16.

The load detection device 5 detects when a load exceeding a certain level is applied to the hook 16. As shown in FIG. 2, for example, the load detection device 5 is provided between the movable member 19 provided so as to be movable up and down in the box 17 and the movable member 19 and the bottom portion 17a of the box 17. A coil spring 20 for urging 19 to an upper position and a movable member detector 21 (limit switch in the present embodiment) for detecting the movable member 19 when the movable member 19 is in a lower position are provided. Further, a connecting tool 15 is attached to the movable member 19, and when an object having a certain weight or more is hung on the hook 16 or a certain load or more is applied, the load is applied to the load detector. It is transmitted to the movable member 19 via the 4 and the connecting tool 15. As a result, the movable member 19 moves from the upper position (see FIG. 2A) to the lower position (see FIG. 2B) against the urging force of the spring 20. When the movable member 19 moves to the lower position, the movable member detector 21 sends a signal to the pneumatic control device 7 indicating that the object is suspended.

The operation device 6 is for the operator to perform various operations on the elevating device 1, and in the present embodiment, a wireless communication type pendant switch is used. When the operator performs various operations using the operation device 6, signals corresponding to the various operations are transmitted to the valve control device 30 via the wireless receiver 22 of the pneumatic control device 7.

The pneumatic control device 7 controls the air pressure supplied to the air cylinder 3 and the like based on the information received from the load detector 4, the load detector 5, the operating device 6, and the like. In the present embodiment, the pneumatic control device 7 is composed of the valves shown in FIG. 3, the valve control device 30, the wireless receiver 22, and the like. Hereinafter, the details of the pneumatic control device 7 will be described.

In the pneumatic circuit shown in FIG. 3, the main supply path 24 is connected to the air supply source 31 via the lever operation valve 32. In the main supply path 24, in order from the upstream side, the brake pressure supply path 37, the fifth pressure regulating path 38, the fourth pressure regulating path 39, the third pressure regulating path 40, the second pressure regulating path 43, and the first pressure regulating path The road 41 is branched and formed.

The brake pressure supply path 37 supplies air pressure from the main supply path 24 to the brake unit 36 attached to the air cylinder 3. An electromagnetic switching valve SV1D is provided in the middle of the brake pressure supply path 37, and when the electromagnetic switching valve SV1D is in a non-excited state (at the right position b shown in FIG. 3), it is inside the brake unit 36. The air is exhausted and the piston rod 3a is braked so as not to fall. Further, when the electromagnetic switching valve SV1D is in the excited state (at the left position a shown in FIG. 3), air pressure is supplied to the brake unit 36, and the piston rod 3a can operate freely without being braked. ..

The fifth pressure regulating path 38 connects the main supply path 24 and the first port of the electromagnetic switching valve SV1F. A fifth pressure adjusting valve R5 is provided in the middle of the fifth pressure adjusting passage 38.

The fourth pressure regulating path 39 connects the main supply path 24 and the second port of the electromagnetic switching valve SV1F. A fourth pressure regulating valve R4 is provided in the middle of the fourth pressure regulating path 39.

The third pressure control path 40 connects the main supply path 24 and the first port of the electromagnetic switching valve SV1E. A third pressure adjusting valve R3 is provided in the middle of the third pressure adjusting passage 40. The second port of the electromagnetic switching valve SV1E and the third port of the electric switching valve SV1F are connected to each other via the first intermediate path 42.

The second pressure regulating path 43 connects the main supply path 24 and the second port of the electromagnetic switching valve SV1C. A second pressure adjusting valve R2 is provided in the middle of the second pressure adjusting passage 43. The first port of the electromagnetic switching valve SV1C and the third port of the electromagnetic switching valve SV1E are connected via the second intermediate path 44.

The fourth port of the electromagnetic switching valve SV1C and the second port of the electromagnetic switching valve SV1B are connected to each other via the third intermediate path 45.

A silencer 46 is connected to the first port of the electromagnetic switching valve SV1B. The fourth port of the electromagnetic switching valve SV1B is connected to the rod side port of the air cylinder 3 via the rod side supply path 48. A speed control valve SC1 for adjusting the operating speed of the air cylinder 3 is provided in the middle of the rod side supply path 48. Further, a pressure switch PS1 is provided to detect the pressure between the speed control valve SC1 and the electromagnetic switching valve SV1B. When the pressure switch PS1 detects an abnormal pressure below a certain level, the valve control device 30 described later switches the electromagnetic switching valve SV1D to the right position b. As a result, the air in the brake unit 36 is exhausted, and the piston rod 3a is braked so as not to fall.

The first pressure regulating path 41 connects the main supply path 24 and the second port of the electromagnetic switching valve SV1A. A first pressure adjusting valve R1 is provided in the middle of the first pressure adjusting passage 41. A silencer 46 is attached to the first port of the electromagnetic switching valve SV1A. The fourth port of the electromagnetic switching valve SV1A is connected to the head side port of the air cylinder 3 via the head side supply path 51.

The pilot pressure is supplied from the main supply path 24 to the electromagnetic switching valves SV1A, SV1E, SV1F and the like.

The valve control device 30 is the electromagnetic switching valves SV1A to SV1F based on information such as signals sent from the load detector 4, the load detection device 5 (movable member detector 21), the pressure switch PS1 and the operation device 6. The solenoids SOL1a to SOL1f are put into an excited state or a non-excited state. As a result, the valve control device 30 controls the air pressure supplied to the air cylinder 3. The valve control device 30 can be configured by using, for example, a PLC (programmable logic controller) or the like.

Next, a method of setting the set pressure of each pressure adjusting valve R1 to R5 will be described.

<About the set pressure of the 1st and 2nd pressure control valves>
The first pressure adjusting valve R1 sets the air pressure to be supplied to the head side of the air cylinder 3. That is, in the state shown in FIG. 3, the compressed air supplied from the main supply path 24 to the first pressure regulating path 41 is depressurized to the set pressure R1p by the first pressure adjusting valve R1 and passed through the electromagnetic switching valve SV1A. Is supplied to the head side of the air cylinder 3. As a result, the air pressure on the head side of the air cylinder 3 becomes the same as the set pressure R1p.

The second pressure adjusting valve R2 sets the air pressure to be supplied to the rod side of the air cylinder 3 when the load detecting device 5 does not detect the load. That is, when the load detection device 5 does not detect the load, the valve control device 30 sets the electromagnetic switching valve SV1B and the electromagnetic switching valve SV1C to the right position b as shown in FIG. As a result, the compressed air supplied from the main supply path 24 to the second pressure regulating path 43 is depressurized to the set pressure R2p by the second pressure adjusting valve R2 and supplied to the rod side of the air cylinder 3, and the air cylinder 3 The air pressure on the rod side is set to the same pressure as the above set pressure R2p.

The set pressure R1p and the set pressure R2p balance the vertical forces applied to the piston rod 3a of the air cylinder 3 when the object is not suspended from the hook 16 (when no load is applied to the hook 16). Is set to. That is, when the upward thrust of the piston rod 3a is T0 and the downward force applied to the piston rod 3a when the object is not suspended from the hook 16 is Fd1, the relationship of the following equation (1) is satisfied.
T0 = Fd1 ... (1)
When the effective cross-sectional area of the head side chamber of the air cylinder 3 is Sh and the effective cross-sectional area of the rod side chamber of the air cylinder 3 is Sr, the upward thrust T0 can be expressed by the following equation (2).
T0 = R2p x Sr-R1p x Sh ... (2)
When the thrust T0 upward from the equations (1) and (2) is eliminated, the following equation (3) is established.
R2p × Sr-R1p × Sh = Fd1 ... (3)
The downward force Fd1 applied to the piston rod 3a can be obtained from the weight of the piston, the weight of the piston rod 3a, the weight of each member applied to the piston rod 3a, and the like. Since it is a constant value, if the value of the set pressure R1p is determined, the value of the set pressure R2p is naturally determined.
Any value can be set as the set pressure R1p. However, it is desirable to set the set pressure R1p to a somewhat large pressure so that the piston rod 3a can be moved up and down at high speed when the object is not suspended (this raising and lowering operation will be described later). .. For example, as the set pressure R1p, a pressure value of about 0.1 Mpa can be set as the gauge pressure.

<About the set pressure of the 3rd pressure control valve>
The third pressure regulating valve R3 determines the air pressure supplied to the rod side of the air cylinder 3 when the load detector 4 detects a load within the range from the predetermined lower limit threshold value Wlow to the predetermined upper limit threshold value Why. It is to be set. That is, when the load detector 4 detects a load within the above range, the valve control device 30 shifts the electromagnetic switching valve SV1C to the left while keeping the electromagnetic switching valve SV1B in the right position b from the state shown in FIG. The position a is switched, and the electromagnetic switching valve SV1E is switched to the left position a. As a result, the compressed air supplied from the main supply path 24 to the third pressure regulating path 40 is depressurized to the set pressure R3p by the third pressure adjusting valve R3 and supplied to the rod side of the air cylinder 3, and the air cylinder 3 The air pressure on the rod side is the same as the set pressure R3p.

The preferable value of the set pressure R3p can be obtained as follows. That is, when the air pressure on the rod side of the air cylinder 3 is set to the set pressure R3p and the air pressure on the head side of the air cylinder 3 is set to the set pressure R1p, the upward thrust T1 (third) generated in the air cylinder 3 due to these differential pressures. 1) and when the object (object to which no external force is applied) is suspended from the hook 16 (hereinafter, the state at this time is also referred to as "reference state") downwardly applied to the piston rod 3a. The set pressure R3p is obtained so that the force Fd2 of the above is balanced. Such a set pressure R3p can be expressed by the following equation (4).
T1 = R3p x Sr-R1p x Sh = Fd2 ... (4)
Then, once the weight of the object is determined, the downward force Fd2 applied to the piston rod 3a is derived from the weight of the piston, the weight of the piston rod 3a, and the weight of each member applied to the piston rod 3a (including the weight of the object). Since it can be determined, the effective cross-sectional areas Sr and Rh of the air cylinder 3 are also determined, and the value of the set pressure R1p can also be determined by the procedure described above, the value of the set pressure R3p can be determined using the equation (4). Can be asked.

<About the set pressure of the 4th pressure control valve>
When the load detector 4 detects a load exceeding the upper limit threshold value Why, the fourth pressure adjusting valve R4 is on the rod side of the air cylinder 3 until the load drops below the predetermined lower assist release threshold value Wda. It sets the air pressure to be supplied to. That is, when the load detector 4 detects a load exceeding the upper limit threshold value Why, the valve control device 30 shifts the electromagnetic switching valve SV1C to the left while keeping the electromagnetic switching valve SV1B at the right position b from the state shown in FIG. The position a is switched, and the electromagnetic switching valve SV1E and the electromagnetic switching valve SV1F are left at the right position b. As a result, the compressed air supplied from the main supply path 24 to the fourth pressure regulating path 39 is depressurized to the set pressure R4p by the fourth pressure adjusting valve R4 and supplied to the rod side of the air cylinder 3, and the air cylinder 3 The air pressure on the rod side is the same as the set pressure R4p. After that, when the load detected by the load detector 4 becomes equal to or less than the lower assist release threshold value Wda, the valve control device 30 switches the electromagnetic switching valve SV1C to the left position a and applies the air pressure of the set pressure R2p to the rod side of the air cylinder 3. Supply. The lower assist release threshold value Wda can be set in the range of the upper limit threshold value Whi or less and the reference load Wref or more, which will be described later. Here, the reference load Wref is a load detected by the load detector 4 in the above-mentioned "reference state".

The value of the set pressure R4p is such that when the operator applies a predetermined force downward to the object (for example, 30 N), the object starts to descend with a force substantially equal to the magnitude of the force. It is desirable to set. The value of such a set pressure R4p can be obtained as follows.
First, when the air pressure on the rod side of the air cylinder 3 is set to the set pressure R4p and the air pressure on the head side of the air cylinder 3 is set to the set pressure R1p, the upward thrust T2 (first) generated in the air cylinder 3 due to these differential pressures. The pulling force of 2) is expressed by the following equation (5).
T2 = R4p x Sr-R1p x Sh ... (5)
Further, the subtraction value Vm1 obtained by subtracting the thrust T2 from the thrust T1 is expressed by the following equation (6). However, T1> T2.
Vm1 = T1-T2 ... (6)
Then, when the worker applies a force of a predetermined magnitude downward to the object, the object starts to descend with the same force as the magnitude of the force, and the reference is made from the upper limit threshold value Why. Since the subtraction value Vm2 obtained by subtracting the load Threshold and the subtraction value Vm1 are the same, the following equation (7) is established.
Vm2 = Why-Wref = Vm1 ... (7)
An arbitrary value can be set as the upper limit threshold Wh, but by setting the subtraction value Vm2 (upper limit threshold Wh-reference load Wref) to about 30 N, the object can be lowered relatively without discomfort. ..
Then, if the subtraction value Vm2 is determined, the subtraction value Vm1 is also determined from the equation (7), and T1 and R1p are also determined. The set pressure R4p can be obtained from (8).
Vm1 = T1- (R4p x Sr-R1p x Sh) ... (8)

<About the set pressure of the 5th pressure control valve>
When the load detector 4 detects a load that is less than the lower limit threshold value, the fifth pressure regulating valve R5 is a rod of the air cylinder 3 until the load rises to a predetermined upper assist release threshold value Waa or more. It sets the air pressure to be supplied to the side. That is, when the load detector 4 detects a load that is less than the lower limit threshold value, the valve control device 30 sets the electromagnetic switching valve SV1C from the state shown in FIG. 3 while keeping the electromagnetic switching valve SV1B at the right position b. The electromagnetic switching valve SV1F is switched to the left position a while the electromagnetic switching valve SV1E is switched to the left position a and the electromagnetic switching valve SV1E is set to the right position b. As a result, the compressed air supplied from the main supply path 24 to the fifth pressure regulating path 38 is depressurized to the set pressure R5p by the fifth pressure adjusting valve R5 and supplied to the rod side of the air cylinder 3, and the air cylinder 3 The air pressure on the rod side is the same as the set pressure R5p. After that, when the load detected by the load detector 4 becomes equal to or higher than the upper assist release threshold value Waa, the valve control device 30 switches the electromagnetic switching valve SV1C to the left position a and applies the air pressure of the set pressure R2p to the rod side of the air cylinder 3. Supply. The upper assist release threshold value Waa can be set in the range of the lower limit threshold value Wlow or more and the reference load Wref or less.

The value of the set pressure R5p is such that when the operator applies a predetermined force upward to the object (for example, a force of 30 N), the object starts to rise with a force of the same magnitude as the force. It is desirable to set to. The value of such a set pressure R5p can be obtained as follows.
First, when the air pressure on the rod side of the air cylinder 3 is set to the set pressure R5p and the air pressure on the head side of the air cylinder 3 is set to the set pressure R1p, the upward thrust T3 (third) generated in the air cylinder 3 due to these differential pressures. The pulling force of 3) is expressed by the following equation (9).
T3 = R5p x Sr-R1p x Sh ... (9)
Further, the subtraction value Vm3 obtained by subtracting the thrust T1 from the thrust T3 is expressed by the following equation (10). However, T3> T1.
Vm3 = T3-T1 ... (10)
Then, when the worker applies a force of a predetermined magnitude upward to the object, the object starts to rise with the same force as the magnitude of the force, the lower limit from the reference load Threshold. Since the subtraction value Vm4 obtained by subtracting the threshold value Wlow and the subtraction value Vm3 are the same, the following equation (11) is established.
Vm3 = Wref-Wlow = Vm4 ... (11)
An arbitrary value can be set as the lower limit threshold value, but by setting the subtraction value Vm3 (reference load Wref-lower limit threshold value low) to about 30 N, the object can be raised relatively comfortably. can.
Then, if the subtraction value Vm3 is determined, the subtraction value Vm4 is also determined from the equation (11), and T1, R1p, Sr, and Sh are also determined. Therefore, the equation (9) is substituted into the equation (10) to substitute T3. The set pressure R5p can be obtained from the eliminated following equation (12).
Vm4 = (R5p × Sr-R1p × Sh) -T1 ... (12)

The above-mentioned upper limit threshold value Why, lower limit threshold value Wlow, upper assist release threshold value Waa, and lower assist release threshold value Wda can be set by a predetermined operation in the valve control device 30 (threshold value setting means). Further, the set pressure of each pressure adjusting valve R1 to R5 can be set by a predetermined operation in each pressure adjusting valve R1 to R5 (first to third pulling force setting means).

Next, a case where an object is suspended from the elevating device 1 and used will be described.

First, the load of the object to be suspended on the elevating device 1 and other objects (sling or the like connecting the object and the hook 16) is specified, and the load is set as the reference load Wref. In this embodiment, it is assumed that the reference load Wref = 1000N.

Next, a value (1030N in the present embodiment) obtained by adding a predetermined value (30N in the present embodiment) to the reference load Wref is set as the upper limit threshold value Why, and this upper limit threshold value Why is set by a predetermined operation to the valve control device. Set to 30. Further, a value (970N in the present embodiment) obtained by subtracting a predetermined value (30N in the present embodiment) from the reference load Wref is set as the lower limit threshold value Wlow, and this lower limit threshold value Wlow is also a valve control device by a predetermined operation. Set to 30. Further, a value (1005N in this embodiment) obtained by adding a predetermined value (5N in this embodiment) to the reference load Wref is set as a lower assist release threshold value Wda, and this lower assist release threshold value Wda is set by a predetermined operation. It is set in the valve control device 30. Further, a value (995N in this embodiment) obtained by subtracting a predetermined value (5N in this embodiment) from the reference load Wref is set as an upper assist release threshold value Waa, and this upper assist release threshold value Waa is set by a predetermined operation. It is set in the valve control device 30. If the upper limit threshold value Why and the lower limit threshold value Wlow are set to about ± 30 N with respect to the reference load Wref, the elevating device 1 becomes easy to handle. The worker who is an employee of the applicant of the present application has already experienced that it is easiest to handle when the upper limit threshold value Why and the lower limit threshold value Wlow are actually set to about ± 30N with respect to the reference load Wref.

Next, the set pressures R1p to R5p of the first pressure regulating valves R1 to the fifth pressure regulating valves R5 obtained by the method for determining the set pressures R1p to R5p described above are used as the first pressure regulating valves R1 to the fifth pressure. Set for the regulating valve R5.

As described above, when the elevating device 1 in which various set values and various threshold values are set is in the operating state, a predetermined air pressure is supplied from the air supply source 31 to the main supply path 24, and the valve is released from the state shown in FIG. The control device 30 switches the electromagnetic switching valve SV1D to the left position a, and the braking by the brake unit 36 is released. In a state where the object is not suspended from the hook 16, the valve control device 30 determines this from the output signal of the load detection device 5, and during that time, a predetermined operation is performed by the operation device 6, whereby the biston rod 3a can be raised and lowered at a relatively high speed. That is, when the operator performs a predetermined operation in the operating device 6, the electromagnetic switching valve SV1A switches to the left position a while the electromagnetic switching valve SV1B remains in the right position b, and the air on the head side of the cylinder 3 is exhausted. The cylinder rod 3a rises at a relatively high speed. Further, when the operator performs another predetermined operation in the operating device 6, the electromagnetic switching valve SV1A is switched to the left position a while the electromagnetic switching valve SV1A remains at the right position b, and the air on the rod side of the cylinder 3 is exhausted. Then, the cylinder rod 3a descends at a relatively high speed. The function of raising and lowering the piston rod 3a at such a high speed can be effectively utilized when the object is not suspended from the hook 13.

Next, the operation of the elevating device 1 when the object is suspended from the hook 13 and the operator applies a vertical force to the object will be described. In the following description, it is assumed that the electromagnetic switching valve SV1D is located at the left position a and the braking by the brake unit 36 is released.

First, as shown in FIG. 4A, when the object W is suspended from the hook 13 of the elevating device 1, the load detector 4 receives the total load of the object W suspended from the hook 16 and the sling 23. (1000N) is detected. Since the load (1000N) detected by the load detector 4 is within the range from the lower limit threshold value Wlow (970N) to the upper limit threshold value Why (1030N), the valve control device 30 has a first pulling force by the air cylinder 3. Air pressure is supplied to the air cylinder 3 so as to generate (thrust T1). Specifically, from the state shown in FIG. 3, the electromagnetic switching valve SV1C is switched to the left position a and the electromagnetic switching valve SV1E is switched to the left position a while the electromagnetic switching valve SV1B is in the right position b (hereinafter, "" It is also called "valve state without assist"). As a result, as shown in FIG. 4A, the upward thrust T1 (1000N + αN) generated by the air cylinder 3 and the downward force Fd2 (1000N + α) applied to the piston rod 3a are balanced, and the object W moves up and down. Maintain a stopped state on the spot without any problems. The αN is a value obtained by subtracting the load detected by the load detector 4 from the load applied to the piston rod 3a, and corresponds to the weight of the slide frame 2, the piston rod 3a, the piston, the load detector, the load monitor 8, and the like. do.

Next, as shown in FIG. 4B, when the load detected by the load detector 4 exceeds the upper limit threshold Why (1030N) by the operator applying a downward force to the object W, the valve control is performed. The device 30 supplies air pressure to the air cylinder 3 so that the air cylinder 3 generates a second pulling force (thrust T2). Specifically, a state in which the electromagnetic switching valve SV1E is switched to the right position b (hereinafter, also referred to as “lower assist valve state”) is formed from the above-mentioned “no assist valve state”. As a result, the air cylinder 3 generates an upward thrust T2 (970N + αN) smaller than the downward force Fd2 (1000N + α) applied to the piston rod 3a, and the object W is lowered by the force of 30N. That is, the worker is assisted by the force for moving the object W downward.

After that, as shown in FIG. 4C, even if the load detected by the load detector 4 is slightly smaller than the upper limit threshold value Why (1030N), a value exceeding the lower assist release threshold value Wda (1005N) is detected. As long as the air cylinder 3 continues to maintain the upward thrust T2, the force for moving the object W downward is continuously assisted.

After that, when the worker loosens the downward force on the object W, or the worker releases the hand from the object W, and the load detector 4 detects a load equal to or less than the lower assist release threshold Wda (1005N). The valve control device 30 supplies air pressure to the air cylinder 3 so that the air cylinder 3 generates the first pulling force (thrust T1) again. Specifically, by switching the electromagnetic switching valve SV1E to the left position a from the above "lower assist valve state", the "non-assisted valve state" is formed again. As a result, as shown in FIG. 4D, the air cylinder 3 again generates an upward thrust T1 (1000N + αN) that balances the downward force Fd2 (1000N + α) applied to the piston rod 3a, and the assist force becomes zero. ..

On the other hand, from the state shown in FIG. 5A, as shown in FIG. 5B, the load detected by the load detector 4 is the lower limit when the operator applies an upward external force to the object W. When the value is less than the threshold value Wlow (970N), the valve control device 30 supplies air pressure to the air cylinder 3 so that the air cylinder 3 generates a third pulling force (thrust T3). Specifically, from the above-mentioned "no assist valve state", the electromagnetic switching valve SV1E is switched to the right position b and the electromagnetic switching valve SV1F is switched to the left position a (hereinafter, also referred to as "upper assist valve state"). To form. As a result, the air cylinder 3 will generate an upward thrust T3 (1030N + αN) larger than the downward force Fd2 (1000N + α) applied to the piston rod 3a, and the object W will rise by the force of 30N. That is, the worker is assisted by the force for moving the object W upward.

After that, as shown in FIG. 5C, even if the load detected by the load detector 4 is slightly larger than the lower limit threshold value Wlow (970N), a value less than the upper assist release threshold value Waa (995N) is detected. As long as the air cylinder 3 continues to maintain the thrust T3, the force for moving the object W upward is continuously assisted.

After that, when the worker loosens the upward force on the object W, or the worker releases the hand from the object W, and the load detector 4 detects a load equal to or higher than the upper assist release threshold Waa (995N). The valve control device 30 supplies air pressure to the air cylinder 3 so that the air cylinder 3 generates the first pulling force (thrust T1) again. Specifically, the electromagnetic switching valve SV1E is switched to the left position a from the above "upper assist valve state", and the electromagnetic switching valve SV1F is switched to the right position b to form the "unassisted valve state" again. As a result, as shown in FIG. 5D, the air cylinder 3 again generates an upward thrust T1 (1000N + αN) that balances the downward force Fd2 (1000N + α) applied to the piston rod 3a, and the assist force becomes zero. ..

According to the elevating device 1 according to the first embodiment described above, the value (30N) obtained by subtracting the second pulling force T2 (970N + αN) from the first pulling force T1 (1000N + αN) and The value (30N) obtained by subtracting the reference load (970N) from the upper limit threshold (1030N) is the same, and the first pulling force (1000N + αN) is subtracted from the third pulling force (1030N + αN). Since the obtained value (30N) and the value (30N) obtained by subtracting the lower limit threshold (970N) from the reference load (1000N) are the same, the force applied by the operator to the object W in the vertical direction. The magnitude of the assist force is the same as the magnitude of the assist force when the assist force is generated. Therefore, the operator can smoothly move the object W up and down.

Further, since the force applied by the operator to the object W in the vertical direction is accurately and instantly detected by the load detector 4, the assist force desired by the operator can be instantly generated. As a result, the elevating device 1 is excellent in responsiveness and easy to handle.

[Second Embodiment]
Hereinafter, the elevating device according to the second embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 6, the elevating device 1A according to the second embodiment includes an air cylinder 3 described in the first embodiment, a load detector 4 attached to the air cylinder 3, a load detector 5, and the like. Two sets are provided, and the pneumatic control device 7A performs the air pressure supply control described in the first embodiment for each air cylinder 3 (for each set).

The internal configuration of the pneumatic control device 7A also includes substantially two sets of the pneumatic control devices 7 according to the first embodiment. However, the valve control device 30A is integrated into one unit. The valve control device 30A is exceptionally second to the two air cylinders 3 based on the information sent from each load detector 4, each load detection device 5, each pressure switch PS1, PS2 and the operation device 6. The air pressure supply control described in the first embodiment is performed. As shown in the pneumatic circuit diagram of FIG. 6, the electromagnetic switching valves SV1A to SV1F and the electromagnetic switching valves SV2A to SV2F are the same, respectively, and the third pressure regulating valves R3 to the fifth pressure regulating valves R5 and the sixth are the same. The pressure regulating valves R6 to the eighth pressure regulating valves R8 are also the same except for the set pressure.

Next, a case where one object is suspended from two air cylinders 3A and 3B of the elevating device 1A will be described.

First, as shown in FIG. 7, the values detected by the load detectors 4A and 4B provided in the air cylinders 3A and 3B are determined by suspending the predetermined two points in the object W to the air cylinders 3A and 3B. Specify and set the values as the reference loads WrefA and WrefB for each air cylinder 3A and 3B. In this embodiment, the reference load WrefA on one air cylinder 3A side is assumed to be 400N, and the reference load WrefB on the other air cylinder 3B side is assumed to be 600N.

Next, a value (430N in this embodiment) obtained by adding a predetermined value (30N in this embodiment) to the reference load WrefA pertaining to one air cylinder 3A is set as an upper limit threshold Whia, and this upper limit threshold Whia Is set in the valve control device 30A by a predetermined operation. Further, a value (370N in the present embodiment) obtained by subtracting a predetermined value (30N in the present embodiment) from the reference load WrefA is set as the lower limit threshold value WlowA, and this lower limit threshold value WlowA is also a valve control device by a predetermined operation. Set to 30A. Further, a value (405N in this embodiment) obtained by adding a predetermined value (5N in this embodiment) to the reference load WrefA is set as a lower assist release threshold value WdaA, and this lower assist release threshold value WdaA is also set by a predetermined operation. Set to the valve control device 30A. Further, a value (395N in this embodiment) obtained by subtracting a predetermined value (5N in this embodiment) from the reference load WrefA is set as an upper assist release threshold value WaaA, and this upper assist release threshold value WaaA is also obtained by a predetermined operation. Set to the valve control device 30A.

Next, a value (630N in the present embodiment) obtained by adding a predetermined value (30N in the present embodiment) to the reference load WrefB related to the other air cylinder 3B is set as the upper limit threshold value WhyB, and the upper limit threshold value WhiB is set. Is set in the valve control device 30A by a predetermined operation. Further, a value (570N in the present embodiment) obtained by subtracting a predetermined value (30N in the present embodiment) from the reference load WrefB is set as the lower limit threshold value WlowB, and this lower limit threshold value WlowB is also the valve control device 30A by a predetermined operation. Set to. Further, a value (605N in this embodiment) obtained by adding a predetermined value (5N in this embodiment) to the reference load WrefB is set as a lower assist release threshold value WdaB, and this lower assist release threshold value WdaB is also set by a predetermined operation. Set to the valve control device 30A. Further, a value (595N in this embodiment) obtained by subtracting a predetermined value (5N in this embodiment) from the reference load WrefB is set as an upper assist release threshold value WaaB, and this upper assist release threshold value WaaB is set by a predetermined operation. Set to the valve control device 30A.

Next, the set pressures R1p to R5p of the first pressure regulating valves R1 to the fifth pressure regulating valves R5 obtained by the method for determining the set pressures R1p to R5p described in the first embodiment are subjected to the respective first pressure regulating valves R1. -Set for the 5th pressure control valve R5. Further, for the sixth pressure regulating valve R6 to the eighth pressure regulating valve R8, the same procedure as the method for determining the set pressures R3p to R5p of the third pressure regulating valve R3 to the fifth pressure regulating valve R5 corresponding to these valves is applied. The set pressures R6p to R8p are obtained, and the obtained values are set for the sixth pressure adjusting valve R6 to the eighth pressure adjusting valve R8, respectively.

Hereinafter, one object is suspended from two air cylinders 3A and 3B of the elevating device 1A in which various set values and threshold values are set, and the elevating device 1A when an operator applies a vertical force to the object. The operation will be described. In the following description, it is assumed that the electromagnetic switching valves SV1D and SV2D are both located at the left position a and the braking by the brake unit 36 is released. Further, the object W of the present embodiment is a long object whose center of gravity is biased to one side.

As shown in FIG. 7, when the object W is suspended from the hooks 13 of the two air cylinders 3, one load detector 4A uses a part of the object W suspended from the hook 16 and the sling 23. The total load (400N) is detected. The other load detector 4B detects the remaining portion of the object W suspended from the hook 16 and the total load (600N) of the sling 23. Since the load (400N) detected by one of the load detectors 4A is within the range from the lower limit threshold value WlowA (370N) to the upper limit threshold value WhyA (530N), the valve control device 30A has the air cylinder 3A first pulled up. Air pressure is supplied to the air cylinder 3A so as to generate a force T1 (400N + αN). Since the load (600N) detected by the other load detector 4B is also within the range from the lower limit threshold value WlowB (570N) to the upper limit threshold value WhyB (630N), the valve control device 30A has the air cylinder 3B as the first. Air pressure is supplied to the air cylinder 3B so as to generate a pulling force T1 (600N + αN). Specifically, from the state shown in FIG. 6, the electromagnetic switching valves SV1C and SV2C are switched to the left position a, and the electromagnetic switching valves SV1E and SV2E are set to the left position a while the electromagnetic switching valves SV1B and SV2B are set to the right position b. A switched state (hereinafter, also referred to as "valve state A without assist") is formed. As a result, the first pulling force T1 (400N + αN) generated by the air cylinder 3A and the downward force Fd2 (400N + α) applied to the piston rod 3a are balanced, and the first pulling force T1 (100N + αN) generated by the air cylinder 3B is balanced. 600N + αN) and the downward force Fd2 (600N + α) applied to the piston rod 3a are balanced, and the object W maintains a stopped state on the spot without moving up and down. In addition, αN is a value similar to the value described in the first embodiment.

In the above state, as shown in FIG. 8, when the operator applies a downward external force to a specific position of the object W, a partial load of the external force is detected by one of the load detectors 4A. It is added to the load, and the load of the surplus of the external force is added to the load detected by the other load detector 4B. When the load detected by one of the load detectors 4A exceeds the upper limit threshold value WhyA (430N), the valve control device 30A tells the air cylinder 3A that the air cylinder 3A generates a second pulling force T2. To supply air pressure. Further, when the load detected by the other load detector 4B exceeds the upper limit threshold WhiB (630N), the valve control device 30A causes the air cylinder 3B to generate a second pulling force T2. Air pressure is supplied to 3B. For example, when the load detected by both load detectors 4A and 4B exceeds the upper limit threshold values WhiA and WhiB, the valve control device 30A switches the electromagnetic switching valves SV1E and SV2E from the above-mentioned "valve state A without assist". A state in which the position is switched to the right position b (hereinafter, also referred to as “lower assist valve state B”) is formed. As a result, as shown in FIG. 8, the two air cylinders 3A and 3B generate a second pulling force T2 (370N + αN, 570N + αN) smaller than the downward force Fd2 (400N + αN, 600N + αN) applied to the piston rod 3a. The object W is lowered by a force of 60N. That is, the worker is assisted by the force for moving the object W downward. After that, as shown in FIG. 9, even if the load detected by the load detectors 4A and 4B is slightly smaller than the upper limit thresholds WhiA (430N) and WhiB (630N), the lower assist release thresholds WdaA (405N) and WdaB (605N) are used. ), The air cylinders 3A and 3B continue to maintain the upward thrust T2, and the force for moving the object W downward is assisted.

After that, the load detectors 4A and 4B set the lower assist release threshold WdaA (405N) as shown in FIG. 10 by loosening the force for pushing the object W downward or releasing the hand from the object W. When a load of WdaB (605N) or less is detected, the valve control device 30A applies the air cylinders 3A and 3B to the air cylinders 3A and 3B so that the air cylinders 3A and 3B generate the first pulling force (thrust T1) again. Supply air pressure. Specifically, the "unassisted valve state A" is formed again by switching the electromagnetic switching valves SV1E and SV2E to the left position a from the above "lower assist valve state A". As a result, the air cylinders 3A and 3B again generate a first pulling force T1 (400N + αN, 600N + αN) that balances with the downward force Fd2 (400N + αN, 600N + αN) applied to the piston rod 3a, and the assist force becomes zero.

On the other hand, as shown in FIG. 11, when the operator applies an upward external force to a specific position of the object W, the load of a part of the external force becomes the load detected by one of the load detectors 4A. In addition, the load of the surplus of the external force is added to the load detected by the other load detector 4B. As a result, when the load detected by one of the load detectors 4A becomes a value less than the lower limit threshold WlowA (370N), the valve control device 30A causes the air cylinder 3A to generate a third pulling force T3. Air pressure is supplied to the air cylinder 3A. Further, when the load detected by the other load detector 4B becomes a value less than the lower limit threshold WlowB (570N), the valve control device 30A causes the air cylinder 3B to generate a third pulling force T3. Air pressure is supplied to the air cylinder 3B. For example, when the load detected by both load detectors 4A and 4B is less than the lower limit threshold values WlowA and WlowB, the valve control device 30A changes from the above-mentioned "valve state A without assist" to the electromagnetic switching valve SV1E. , SV2E is switched to the right position b, and the electromagnetic switching valves SV1F and SV2F are switched to the left position a (hereinafter, also referred to as "upper assist valve state A"). As a result, as shown in FIG. 12, the two air cylinders 3A and 3B generate a third pulling force T3 (430N + αN, 630N + αN) larger than the downward force Fd2 (400N + αN, 600N + αN) applied to the piston rod 3a. The object W rises with a force of 60N. That is, the worker is assisted by the force for moving the object W upward.

After that, as shown in FIG. 13, even if the load detected by the load detectors 4A and 4B is slightly larger than the lower limit threshold values WlowA (370N) and WlowB (570N), the upper assist release thresholds WaaA (395N) and WaaB (595N). ) Is detected, the air cylinders 3A and 3B continue to maintain the third pulling force T3, and the force for continuously moving the object W upward is assisted.

After that, the operator loosens the upward force on the object W, releases the hand from the object W, and the load detectors 4A and 4B have a load equal to or higher than the upper assist release thresholds WaaA (385N) and WaaB (585N). When the above is detected, the valve control device 30A supplies air pressure to the air cylinders 3A and 3B so that the air cylinders 3A and 3B generate the first pulling force T1 again. Specifically, by switching the electromagnetic switching valves SV1E and SV2E to the left position a and switching the electromagnetic switching valves SV1F and SV2F to the right position b from the above "upper assist valve state A", the "unassisted valve state A" is performed again. To form. As a result, the air cylinders 3A and 3B generate an upward thrust T1 (400N + αN, 600N + αN) that balances with the downward force Fd2 (400N + αN, 600N + αN) applied to the piston rod 3a, and the assist force becomes zero.
..

According to the elevating device 1A according to the second embodiment described above, even if the object W is a long object, it can be used, and the same operation and effect as those of the first embodiment can be obtained. ..

The present invention can be applied to, for example, a power assist type elevating device capable of raising and lowering a suspended heavy object with a slight force.

W Object 1,1A Power assist type lifting device 3 Air cylinder 3a Piston rod 4 Load detector 7 Pneumatic control device

Claims (4)

An air cylinder that raises and lowers a suspended object by expanding and contracting,
A load detector provided between the air cylinder and the object and detecting the load of an object connected below the air cylinder, and a load detector.
A pneumatic control device that controls the supply of air pressure to the air cylinder,
It is a power assist type elevating device equipped with
The pneumatic control device is used as an air pressure supply control to the air cylinder.
When the load detector detects a load within a range from a predetermined lower limit threshold value to a predetermined upper limit threshold value, the air cylinder is applied to the air cylinder so as to generate a predetermined first pulling force. Supply air pressure,
When the load detector detects a load exceeding the upper limit threshold value, the air pressure is supplied to the air cylinder so that the air cylinder generates a predetermined second pulling force smaller than the first pulling force. death,
When the load detector detects a load that is less than the lower limit threshold value, the air pressure is applied to the air cylinder so that the air cylinder generates a predetermined third pulling force larger than the first pulling force. Supply and
When the load detector detects a load exceeding the upper limit threshold value, the air cylinder causes the second air cylinder until the load drops below a predetermined lower assist release threshold value set below the upper limit threshold value. Air pressure is supplied to the air cylinder so as to generate a pulling force of
When the load detector detects a load that is less than the lower limit threshold value, the air cylinder causes the air cylinder until the load rises to a predetermined upper assist release threshold value set to be equal to or higher than the lower limit threshold value. Air pressure is supplied to the air cylinder so as to generate the pulling force of 3.
A power-assisted elevating device characterized by this. In the power assist type elevating device according to claim 1 ,
The pneumatic control device is
A pulling force setting means for setting the first pulling force, the second pulling force, and the third pulling force by a predetermined operation, respectively.
A threshold value setting means for setting the lower limit threshold value and the upper limit threshold value by a predetermined operation, respectively.
Have,
A power-assisted elevating device characterized by this. An air cylinder that raises and lowers a suspended object by expanding and contracting,
A load detector provided between the air cylinder and the object and detecting the load of an object connected below the air cylinder, and a load detector.
A pneumatic control device that controls the supply of air pressure to the air cylinder,
Equipped with
The pneumatic control device is used as an air pressure supply control to the air cylinder.
When the load detector detects a load within a range from a predetermined lower limit threshold value to a predetermined upper limit threshold value, the air cylinder is applied to the air cylinder so as to generate a predetermined first pulling force. Supply air pressure,
When the load detector detects a load exceeding the upper limit threshold value, the air pressure is supplied to the air cylinder so that the air cylinder generates a predetermined second pulling force smaller than the first pulling force. death,
When the load detector detects a load that is less than the lower limit threshold value, the air pressure is applied to the air cylinder so that the air cylinder generates a predetermined third pulling force larger than the first pulling force. Supply and
The pneumatic control device is
A pulling force setting means for setting the first pulling force, the second pulling force, and the third pulling force by a predetermined operation, respectively.
A threshold value setting means for setting the lower limit threshold value and the upper limit threshold value by a predetermined operation, respectively.
Have,
How to use the power assist type elevating device
The load detected by the load detector when the object is suspended and no external force is applied to the object is defined as a reference load.
The pulling force setting means is used so that the downward load applied to the air cylinder when the load detector detects the reference load and the first pulling force generated by the air cylinder are balanced. Then set the first pulling force,
The pulling force setting means and the threshold value setting means are set so that the value obtained by subtracting the second pulling force from the first pulling force and the value obtained by subtracting the reference load from the upper limit threshold value are substantially the same. Use to set the second pulling force and the upper threshold.
The pulling force setting means and the threshold value setting means are set so that the value obtained by subtracting the first pulling force from the third pulling force and the value obtained by subtracting the lower limit threshold value from the reference load are substantially the same. Use to set the third pulling force and the lower threshold.
How to use the power assist type elevating device. The method of using the power assist type elevating device according to claim 3.
The pneumatic control device is
When the load detector detects a load exceeding the upper limit threshold value, the air cylinder causes the second air cylinder until the load drops below a predetermined lower assist release threshold value set below the upper limit threshold value. Air pressure is supplied to the air cylinder so as to generate a pulling force of
When the load detector detects a load that is less than the lower limit threshold value, the air cylinder causes the air cylinder until the load rises to a predetermined upper assist release threshold value set to be equal to or higher than the lower limit threshold value. Air pressure is supplied to the air cylinder so as to generate the pulling force of 3.
How to use the power assist type elevating device.

Images