JP2007091439A - Cargo handling machine and conveying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo handling machine and a conveying method capable of certainly reducing operation force by stable action. <P>SOLUTION: In the cargo handling machine 11, pressure variation in a cylinder 121 is detected by an auxiliary sensor 21 and when it is detected that the operation force applied to a cargo object 119 has a component in an upward direction in such a state that the inside of the cylinder 121 is set to a load balance pressure P<SB>2</SB>, a control circuit 131 raises an internal pressure of the cylinder 121 by ΔP<SB>1</SB>and generates upward auxiliary force Δf<SB>1</SB>. When it is detected that it has a component in a downward direction, it reduces the internal pressure by ΔP<SB>2</SB>and generates downward auxiliary force Δf<SB>2</SB>. Since the auxiliary force in the same direction as the operation force is added, burden of a worker 125 is reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technical field of a cargo handling machine and a conveyance method, and particularly relates to a cargo handling machine and a conveyance method capable of reducing labor of an operator.

In a factory production line or a warehouse, a wide variety of conveyances are performed such as conveyance associated with the removal and attachment of relatively heavy equipment, conveyance of semi-finished workpieces to the next process, and conveyance of shipped products.
In such various load carrying work, a cargo handling machine which reduces labor and is safe, has a small turn and has mobility and simplicity is used.

Reference numeral 101 in FIG. 1 is an external view of the cargo handling machine according to the present invention and the prior art.
In the basic structure of the cargo handling machine 101, a support column 112 is vertically raised from a cart (or bottom surface) 111, and an arm 115 is attached to an upper end 113 of the support column 112.

  The arm 115 is configured to be able to swing and turn. The front end portion of the arm 115 is a suspended portion 116 that lifts the cargo handling object 119 and is equipped with a clamping mechanism 117 for the cargo handling object.

  In addition to the crane mode in which the cargo handling object 119 is lifted, the load handling machine 101 has a balance that allows the operator to grip and hold the cargo handling object 119 directly and move and transfer freely in a state of zero gravity while the clamp mechanism 117 clamps the cargo handling object. There is a control mode called mode.

The operation in the balance mode will be described with reference to the control block diagram of FIG.
The load handling machine 101 is supported by the piston rod 122 of the air cylinder 121 and the weight of the arm 115, the counterclockwise moment due to the weight of the clamped load 119 with respect to the fulcrum A, as shown in FIG. A clockwise moment is generated by the force point B, and when the two moments are matched, a stopped state (balanced state) is obtained. When the operator 125 applies an operating force to the cargo handling object 119 in this balanced state, the balance of both moments is lost, and the cargo handling object 119 can be moved freely.

For example, in a state where the cargo handling object 119 is clamped by the cargo handling machine 101 and lifted by applying an upward operation force, the weight W ₁ of the cargo handling object 119 and the weight W ₂ of the arm 115 cause the cargo handling object 119 side of the arm 115 to be When the force f ₁ (W ₁ + W ₂ ) in the descending direction (counterclockwise in the figure) is applied and the effective arm length between the fulcrum A of the cargo handling machine 101 and the cargo handling object 119 is L ₁ , f A moment of ₁ × L ₁ works.

On the other hand, if the downward force by the piston rod 122 of the air cylinder is f ₂ and the distance between the fulcrum B and the point of action A is L ₂ , the moment f ₂ × L in the clockwise direction via the fulcrum B ₂ works.
In order to keep the arm 115 of the cargo handling machine 101 in a balanced state, the following equation must be satisfied.

f ₁ × L ₁ = f ₂ × L ₂ (1)
From the above equation (1), in the balance state, the downward force f ₂ by the air cylinder 121 is
f ₂ = f ₁ × L ₁ / L ₂ (2)
Need to be satisfied.

The control circuit 131 needs to increase the internal pressure of the air cylinder 121 so as to generate the same force as f _{2 in} order to maintain the state (balanced state) where the cargo item is lifted. Here, when the pressure receiving area of the piston 124 of the air cylinder 121 is S, the internal pressure P of the air cylinder 121 in the balanced state is
P = f ₂ / S
Can be obtained.

  The pressure control device 132 is roughly divided into an air control type and an electric control type, but the basic circuit operation is the same. An air source 134 is connected to the input pressure port a of the pressure control device, and the output pressure port When the air cylinder 121 is connected to c, and the air pressure P is input from the control circuit 131 to the setting port b, the same air pressure as the input air pressure P is generated at the output pressure port c. .

The operation of the pressure control device 132 will be described with reference to FIG.
First, at time t ₁ , the cargo handling object 119 is clamped by the clamp mechanism 117. At this time, the set pressure of the pressure control device 132 is set to the no-load balance pressure P ₁ during no load, and the internal pressure of the cylinder 121 is also set to that pressure.

Next, when the load balance button 138 is turned on at time t ₂ , the pressure signal output from the control circuit 131 to the setting port b is changed to the load balance pressure P ₂ stored in advance, and the set pressure of the pressure control device 132 is The load balance pressure P ₂ is changed.

The pressure control device 132 has a pressure sensor that detects the pressure of the output pressure port c. When the set pressure is changed, the operation waiting time Δt ₁ set in the pressure control device 132 has elapsed. (Time t ₃ ) The pressure of the output pressure port c is raised and lowered by the supply of air from the air source 134 and the exhaust through the silencer 135, and the pressure of the output port c, that is, the internal pressure of the cylinder 121, is set. To the pressure of the pressure signal input to the load (load balance pressure P ₂ ).

  In this state, a force to cancel the weight is applied to the cargo handling object 119, and the operator 125 can hold the cargo handling object 119 and lift it upward with a slight operating force (ground cutting operation). The lifted cargo item 119 stops in the air even when the operator releases his / her hand. This state is called a load balance state.

After the ground is cut off (time t ₄ ), when the operator 125 applies an operating force to the arm 115 of the cargo handling machine 101 or the clamp mechanism under the arm 115 and moves it up and down, the pressure in the air cylinder 121 is changed to the tip of the arm. It slightly changes depending on the operating force applied to the cargo handling material.

  FIG. 6 shows a pressure change when an operation force having an upward component is applied to the cargo handling object 119 and moved upward, and the internal pressure of the cylinder 121 is slightly reduced. On the other hand, if the cargo handling item 119 is moved downward, the internal pressure of the cylinder 121 slightly increases.

In order to move the cargo handling object 119, it is necessary to move the piston 124 in accordance with the amount of movement of the cargo handling object 119. However, when an operating force is applied to the cargo handling object 119, the pressure control device 132 changes the internal pressure of the cylinder 121. In order to obtain the pressure (load balance pressure P ₂ ) input to the setting port b, the air in the cylinder 121 is supplied and exhausted after a short delay time Δt ₂ , and the movement corresponding to the movement amount of the cargo item 119 is performed. Move the piston 124 by an amount. Thereby, the cargo handling object 119 can be moved with a slight operating force.

Thus, in the load balance state, the operating force required for the operator 125 is reduced, and the cargo handling object 119 can be moved up and down and moved left and right freely with a slight operating force.
However, in the actual cargo handling machine 101, there is a limit to the reduction in operating force due to the following factors.

(1) Sliding friction inside the piston 124 when the air cylinder 121 moves up and down, and sliding friction outside the piston 124 at the connecting portion of the air cylinder 121 and the arm 115
(2) Friction of each arm 115 link
(3) Inertia of arm 115 and cargo 119
(4) Supply / exhaust capacity of the pressure control device 132 If the operation force is light, the worker 125 can operate the cargo handling machine 101 for a long time. However, if the operation force becomes heavy, the worker 125 may become tired or have muscle pain. The cargo handling machine 101 cannot be used for a long time.

  In particular, when transporting the heavy cargo handling object 119 in the balance mode, not only the cargo handling material 119 is heavy, but also the rigidity of the arm 115 is increased to increase the rigidity of the arm 115, and accordingly the joint of the cargo handling machine 101 is increased. Since the friction also increases, a large operating force is required.

  When working for a long time in the work environment using such a cargo handling machine 101, a heavy burden is placed on the worker 125.

In order to reduce the operating force, it is necessary to study and improve not only the frictional force at the joints but also the above factors, but there are structural problems and performance problems of the cargo handling machine 101, etc. For this reason, it was not easy to reduce the operating force.
JP-A-11-147699

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cargo handling machine and a transport method that can reliably reduce an operation force with a stable operation.

The present invention was created to solve the above-described problem, and an arm that lifts a cargo handling object, a cylinder attached to the arm, and a cylinder connected to the cylinder, for supplying and exhausting gas in the cylinder, A pressure control device that adjusts the pressure in the cylinder according to the input pressure signal; and a control circuit that outputs the pressure signal to the pressure control device, and a load balance pressure corresponding to the weight of the cargo item. When the pressure signal indicating is output from the pressure control device, an ascending force generated by the pressure in the cylinder and applied to the cargo handling object via the arm, and a descending force generated by the weight of the cargo handling object Are balanced, and the cargo handling object is stationary in the vertical direction, and when an operating force is applied to the cargo handling object, a balance state is formed in which the cargo handling object can be moved in a desired direction. When the control circuit detects whether the operating force has an upward component or a downward component and changes the pressure signal to have an upward component It is a cargo handling machine configured to generate an upward auxiliary force by increasing the pressure of the cylinder and to generate a downward auxiliary force by decreasing the pressure of the cylinder when it has a downward component.
Further, the present invention is provided with an auxiliary sensor for measuring the pressure in the cylinder, and the control circuit detects increase / decrease in pressure in the cylinder from the measurement result of the auxiliary sensor, and the operating force is directed upward. It is a cargo handling machine which discriminate | determines whether it has a component of this or a component of a downward direction.
Further, the present invention is the cargo handling machine configured such that the control circuit causes the auxiliary force to disappear when a predetermined auxiliary force generation time elapses after the auxiliary force is generated.
Further, according to the present invention, an operation force detection sensor that detects a direction of the operation force is provided between the arm and the cargo handling material, and the control circuit is configured to receive a signal input from the operation force detection sensor, It is a cargo handling machine that determines whether the operating force has an upward component or a downward component.
The present invention is also a cargo handling machine configured to return the pressure signal to a load balance pressure when the operation force detection sensor detects the disappearance of the operation force.
Further, the present invention is the cargo handling machine in which the magnitude of the auxiliary force is set to a magnitude that can maintain the stationaryness in the vertical direction.
Further, the present invention uses a cargo handling machine having an arm for lifting a cargo handling article and a cylinder attached to the arm, and sets the pressure in the cylinder to a load balance pressure corresponding to the weight of the cargo handling article, The lifting force applied to the cargo handling object via the arm due to the pressure in the cylinder is balanced with the descending force generated by the weight of the cargo handling material, the cargo handling object is made to stand up and down, and the handling force is applied to the cargo handling object. Is added, the load handling method forms a balanced state in which the load can be moved in a desired direction, and detects whether the operating force has an upward component or a downward component, and detects the upward direction. When it has a component, it increases the pressure of the cylinder, and generates an upward auxiliary force on the cargo, and when it has a component in the downward direction, it reduces the pressure of the cylinder. A conveyance method for generating a downward assist force to the handling thereof.
Moreover, this invention is a conveying method which erase | eliminates the said auxiliary force, if the disappearance of the said operation force is detected.
Moreover, this invention is a conveying method which detects the component which the said operating force has from the pressure change in the said cylinder.
Further, the present invention is a transport method in which the auxiliary force disappears after a predetermined auxiliary force generation time has elapsed.
Moreover, this invention is a conveying method which makes the magnitude | size of the said auxiliary | assistant force the magnitude | size which the said up-down direction stillness is maintained.

  By using the cargo handling machine and transport method of the present invention, an auxiliary force in the same direction as the upward or downward component of the operating force is generated and applied to the cargo handling material. As a result, the burden on the operator is lightened and the work can be performed for a long time.

Examples of the present invention will be described.
The external appearance of the first example of the present invention and the second example of the cargo handling machines 11 and 12 to be described later is as shown in FIG. 1, and a column 112 is vertically raised from a carriage (or bottom surface) 111. An arm 115 is attached to the upper end 113 so as to be able to swing and swing. Further, the distal end side of the arm 115 is rotatably attached to the root side.

One end portion of the arm 115 is a suspended portion 116 that lifts the cargo handling object 119, and a lower end of the suspended portion 116 is equipped with a cargo handling clamp mechanism 117.
The opposite side of the arm 115 is connected to the piston 124 of the cylinder 121.

FIG. 3 is a control block diagram of the cargo handling machine 11 of the first example, and FIG. 4 is a control block diagram of the cargo handling machine 12 of the second example.
Referring to FIGS. 3 and 4, in the cargo handling machines 11 and 12 of the first example and the second example, the cylinder 121 is connected to the output pressure port c of the pressure control device 132, and the air source 134 is connected to the input pressure port a. The air supply side valve in the pressure control device 132 is controlled so that air can be supplied from the air source 134 into the cylinder 121.

  Further, the exhaust port d of the pressure control device 132 is connected to the atmosphere via a silencer 135, and is configured such that the air in the cylinder 121 can be discharged to the atmosphere by controlling a valve on the exhaust side.

  By such supply and exhaust, the pressure in the cylinder 121 can be raised and lowered. When the pressure in the cylinder 121 increases, the upward force applied to the cargo handling object increases, and decreases when the pressure decreases.

  The setting port b of the pressure control device 132 is connected to the control circuit 131 via the D / A converter 23, and the digital pressure signal output from the control circuit 131 is converted into an analog signal by the D / A converter 23. It is configured to be input to the setting port b after being converted to.

  The pressure control device 132 has a sensor (not shown) that measures the pressure of the output pressure port c, and the pressure control device 132 makes the pressure measured by the sensor equal to the pressure indicated by the pressure signal. The supply / exhaust valve is controlled to supply / exhaust the cylinder 121.

A method for transporting the cargo handling object 119 using the cargo handling machine 11 of the present invention will be described.
Here, the weight of the cargo handling object 119 is known, the load balance pressure P ₂ (P ₂ > 0) for satisfying the expression (2) and canceling the weight of the cargo handling object 119 is stored in the control circuit 131 in advance. Shall.

First, when the cargo handling object 119 is clamped by the clamp mechanism 117 and the load balance button 138 is pressed, a pressure signal indicating the load balance pressure P ₂ is output from the control circuit 131 to the pressure control device 132.

In the initial state, the cylinder 121 is set to the no-load balance pressure P ₁ (P ₁ <P ₂ ), and when the pressure control device 132 is set to the load balance pressure P ₂ , the cylinder 121 is pressurized by supplying air. Is done.

When the pressure in the cylinder rises and becomes the load balance pressure P ₂ , an upward force that cancels the load is applied to the cargo handling object 119, and a balanced state in which the load does not rise or fall in the air can be maintained. In the balance state, it can be moved with a slight operating force.

The operation in the balanced state will be described first with reference to FIG. 3 for the cargo handling machine 11 of the first example.
In the cargo handling machine 11 of the first example, the auxiliary sensor 21 is connected to the cylinder 121, and the pressure in the cylinder 121 is measured by the auxiliary sensor 21.

  The auxiliary sensor 21 is connected to the control circuit 131 via the A / D converter 22. When the auxiliary sensor 21 outputs the measurement result as an analog signal, the auxiliary sensor 21 is converted into a digital signal by the A / D converter 22. Input to the control circuit 131.

When an operating force having an upward component is applied to the arm 115, the cargo handling object 119, etc. in a balanced state, the piston 124 of the cylinder 121 moves downward, so the pressure in the cylinder 121 decreases slightly, and conversely downward When an operating force having a directional component is applied, the piston 124 of the cylinder 121 moves upward, so that the internal pressure of the cylinder 121 slightly increases.
The auxiliary sensor 21 constantly outputs the pressure in the cylinder 121 to the control circuit 131, and the control circuit 131 stores the pressure value input from the auxiliary sensor 21.

  Therefore, the control circuit 131 compares the pressure value input from the auxiliary sensor 21 with the stored pressure value, detects from the comparison result whether the pressure in the cylinder 121 has increased or decreased, and operates the operating force. Can be discriminated whether it has a component in the upward direction or a component in the downward direction.

The control circuit 131 changes the value of the pressure signal output to the pressure control device 132 before the delay time Δt ₂ of the pressure control device 132 elapses when the pressure change in the cylinder 121 is a predetermined value or more. To do.

That is, when it has a component in the upward direction, it is made higher than the load balance pressure P ₂ by a predetermined auxiliary pressure ΔP ₁ (ΔP ₁ > 0) (P ₂ + ΔP ₁ ) and has a component in the downward direction. In this case, the pressure is lowered by a predetermined auxiliary pressure ΔP ₂ (ΔP ₂ > 0) from the load balance pressure P ₂ (P ₂ −ΔP ₂ ).
The pressure controller 132 starts air supply / exhaust after the lapse of the delay time Δt ₂ , and changes the pressure in the cylinder 121 to P ₂ + ΔP ₁ or P ₂ −ΔP ₂ indicated by the pressure signal.

When the internal pressure of the cylinder 121 is increased by the auxiliary pressure ΔP ₁ , the cargo handling object 119 has an upward auxiliary force Δf ₁ (= ΔP ₁ × S × (L ₂ / L ₁ ), S: pressure receiving area of the cylinder 121). since joining, handling product 119 is conveyed upward with the upward operating force f by the sum of forces f + Delta] f ₁ of the auxiliary force Delta] f _1.

When the step-down by the auxiliary pressure [Delta] P _2, downward assist force _{Δf 2 (= ΔP 2 × S} × (L 2 / L 1) is applied to the handling thereof 119, cargo was 119, the downward operation force f auxiliary is conveyed downward by the sum of the force f + Delta] f ₂ forces Delta] f _2.

The control circuit 131 has been set in advance assist force generating time [Delta] T, after the assist force generated time [Delta] T from the time you change the pressure signal has elapsed, the pressure signal, based on the value indicating the load balancing pressure P ₂ After that, when the waiting time Δt ₁ elapses, the internal pressure of the cylinder 121 returns to the load balance pressure P ₂ .

  FIG. 7 is a timing chart showing the circuit operation when the worker 125 first moves the cargo handling item 119 upward and then moves it downward. The horizontal axis in FIG. 7 represents the elapsed time, and the vertical axis represents the pressure in the cylinder 121 (upper side) and the value of the pressure signal (lower side).

First, before the clamping of the cargo material 119 has been pressed unloaded balancing button 139, the values of the pressure signal is set to the no-load balancing pressure P _1, the internal pressure of the cylinder 121 is also in no load balancing pressure P ₁ . No load balance pressure P ₁ <load balance pressure P ₂ .

At time t ₁ ~t _13, the following operation is being performed.
t ₁ : Time when the load 119 is clamped t ₂ : Time when the load balance button 138 is pressed and the pressure signal is set to the load balance pressure P ₂ t ₃ : The operation waiting time Δt ₁ has passed, and the cylinder 121 Time t _{4 when the} pressure is set to the load balance pressure t ₄ : Time when it is detected that an operating force having an upward component is applied to the cargo handling material 119 and the pressure signal is set to P ₂ + ΔP ₁ t ₅ : Delay time The time when Δt ₂ has elapsed and the pressure control device 132 starts to increase the pressure in the cylinder 121 t ₆ : The time when the pressure in the cylinder 121 becomes P ₂ + ΔP ₁ t ₇ : The pressure signal is the load balance pressure P ₂ the returned time t _8: delay time Delta] t ₁ has elapsed, the time t ₉ the pressure of the pressure control device 132 has returned to the load balancing pressure P _2: operation force to the cargo compound 119 having a downward directional component is added Was it There is detected, the pressure signal P ₂ -ΔP ₂ which is set to the time t _10: delay time Delta] t ₂ has elapsed, the pressure control device 132 is a time t ₁₁ which begins to lower the pressure in the cylinder 121: a cylinder 121 T ₁₂ : Time when the pressure signal becomes P ₂ −ΔP ₂ t ₁₂ : Time when the pressure signal is returned to the load balance pressure P ₂ t ₁₃ : Delay time Δt ₁ has passed, and the pressure of the pressure control device 132 becomes the load balance pressure P after a time the time t ₁₃ which has returned to _2, while maintaining a load balancing state to convey the cargo was 119 in place, thereby landing the handling thereof 119.

In this state, when the unload balance button 139 is pressed and the cargo handling machine 101 is set to the no load balance state, when the unclamp button is pressed, the cargo handling object 119 is unclamped.
At this time, since the cargo handling machine 101 is set to the no-load balance state, the arm is kept stationary without being raised.

In the balanced state, the auxiliary forces Δf ₁ and Δf ₂ generated by the auxiliary pressures ΔP ₁ and ΔP ₂ are smaller than the drag force caused by friction inside the machine, and even if the auxiliary forces Δf ₁ and Δf ₂ are generated. When the operation force f is zero, the cargo handling object 119 can move in the air without moving.

Next, the cargo handling machine 12 of the second example of the present invention will be described with reference to FIG.
In the cargo handling machine 12, an operation force detection sensor 18 that detects the direction of the operation force is provided between the arm 115 and the clamp mechanism 117, and when an operation force is applied to the cargo handling object 119 clamped by the clamp mechanism 117. The operation force detection sensor 18 is configured to detect whether the operation force has an upward component or a downward component.
The operation force detection sensor 18 is connected to the control circuit 131, and the detection result of the operation force detection sensor 18 is always input to the control circuit 131.

Similar to the loading machine 11 of the first example, in a balanced state, the operator 125 grips the loading material 119 and the clamp mechanism 117 and applies an operating force, and the control circuit 131 applies an upward operating force to the loading material 119. the pressure in the cylinder 121 is boosted by the auxiliary pressure [Delta] P ₁ detects that, to the magnitude of the P ₂ + ΔP _1.

On the other hand, when it is detected that the downward operation force is applied to reduce the pressure in the cylinder 121 by the auxiliary pressure [Delta] P _2, to the size of P ₂ -ΔP _2.
Thus, the auxiliary force Delta] f _1, Delta] f ₂ is generated, the effort the operator 125 carries the handling thereof is reduced.

Reference numerals t _{1 to} t _{13 in} FIG. 8 indicate times corresponding to the same operations as those of the cargo handling machine 11 of the first example.

The operating force detection sensor 18 is configured to output a positive signal when detecting that the operating force has an upward component, and to output a negative signal when detecting that the operating force has a downward component, at time t _4, t _9, when the operation force is applied to the handling thereof 119 is detected immediately direction of the component, which is output to the control circuit 131.

In the cargo handling machine 11 of the first example, the pressure in the cylinder 121 is maintained at a constant pressure of P ₂ + ΔP ₁ or P ₂ −ΔP ₂ during the auxiliary force generation time ΔT, and during the auxiliary force generation time ΔT. Even if the operating force becomes zero, it cannot be detected and the auxiliary force cannot be extinguished. Therefore, in the cargo handling machine 11 of the first example, the auxiliary forces Δf ₁ and Δf ₂ need to be generated regardless of the presence or absence of the operating force during the auxiliary force generation time ΔT preset by a timer or the like.

Even in the cargo handling machine 12 of the second example, the load balance pressure P ₂ may be returned after a certain auxiliary force generation time ΔT has elapsed. However, according to the operation force detection sensor 18, other than the direction of the operation force. The presence or absence of operating force can also be detected.

Therefore, if it is detected that the operating force has disappeared, the value of the pressure signal can be returned to the load balance pressure P ₂ without maintaining the auxiliary force for a certain period of time, so that after a short delay time Δt ₂ , the pressure in the cylinder 121 can be returned to the load balancing pressure P _2.

  When the direction of the operating force applied to the cargo handling object 119 is changed, the direction of the assisting force to be generated can be changed immediately, so that the assisting force is excellent in following the change of the operating force.

An arrangement example of the operation force detection sensor 18 is shown in FIG.
The cargo handling machine 12 of the second example includes a clamp mechanism 117 configured by a hook-shaped hook and a cylindrical operation grip 142.

  A shaft 141 is vertically inserted into the operation grip 142, and the upper end thereof is attached to the tip of the arm 115, and the hook 117 is attached to the lower end. The operator 125 holds the operation grip 142 in a balanced state. When an operating force is applied, the cargo handling object 119 suspended from the hook 117 can be conveyed.

  Stopper members 144a and 144b are provided at the upper and lower ends of the shaft 141, respectively. Springs 143a and 143b are arranged between the operation grip 142 and the stopper members 144a and 144b. When no operation force is applied to the operation grip 142, the upper and lower ends of the operation grip 142 are the stopper members 144a and 144b. The springs 143a and 143b are separated from the surface by the thickness.

Detection switches 18a and 18b are arranged between the upper end of the operation grip 142 and the stopper member 144a and between the lower end of the operation grip 142 and the stopper member 144b. The operating force detection sensor 18 includes these two detection switches 18a and 18b.
The detection switches 18a and 18b are configured to be OFF when no force is applied and to be turned ON when the force is applied.

  The thickness of the detection switches 18a and 18b is smaller than the distance between the operation grip 142 and the stopper members 144a and 144b. When no operation force is applied to the operation grip 142, any of the stopper members 144a and 144b and the operation grip 142 is used. One of them is not touched and no force is applied. Therefore, when the operating force is not applied, both the two detection switches 18a and 18b are OFF.

  The operation grip 142 is attached so as to be movable in the vertical direction with respect to the shaft 141. When an operation force having an upward component is applied, the operation grip 142 moves upward and compresses the upper spring 143a. The detection switch 18b located above the grip 142 is pressed. As a result, the detection switch 18a is turned ON.

  Conversely, when an operating force having a downward component is applied, the operation grip 142 moves downward, compresses the lower spring 143b, and turns on the detection switch 18b positioned below the operation grip 142.

  The detection switches 18a and 18b are connected to the control circuit 131. When the detection switch 18a above the operation grip 142 is turned ON, a positive voltage is input to the control circuit 131. Conversely, the detection switch below the operation grip 142 is detected. When 18b is turned on, a negative voltage is input (timing chart in FIG. 7).

Control circuit 131, to determine the polarity of the operating force of the input voltage has a downward directional component or having an upward directional component, boosting the pressure in the cylinder 121 by the auxiliary pressure [Delta] P _1, or auxiliary pressure [Delta] P _The pressure can be reduced by ₂ and an auxiliary force can be generated in the same direction as the operating force.

  In addition, although not the detection switches 18a and 18b, although expensive, a load sensor for detecting a load may be disposed between the clamp mechanism 117 and the arm 115 so that the control circuit 131 detects the direction of the operating force. .

  In this case, when the operator 125 grips the cargo handling object 119 and applies an operation force in a balanced state, if the operation force has an upward component, the load applied to the clamp mechanism 117 decreases, and the downward component is reduced. If there is, it will increase. Accordingly, the load value input from the load sensor to the control circuit 131 also changes depending on the direction of the operating force.

  The control circuit 131 obtains the change of the input load force, and can generate an auxiliary force in the same direction as the operation force applied to the load handling object 119, similarly to the load handling machines 11 and 12 of the first and second examples. it can.

In this example as well, as with the cargo handling machine 11 of the first example, the load balance pressure P ₂ may be returned after a certain auxiliary force generation time ΔT has elapsed, but the disappearance of the operating force can be detected by the load sensor. Therefore, as with the cargo handling machine 12 of the second example, when the disappearance of the operating force is detected, the auxiliary force may be extinguished.

  As in the first example of the cargo handling machine 11, the operation force reduction function using the pressure sensor is structurally easy and can be realized at a relatively low cost, but the control circuit 131-D / A converter 23 Since the closed loop of the pressure control device 132, the auxiliary sensor 21, the A / D converter 22, and the control circuit 131 is configured, the control becomes difficult.

  On the other hand, as in the cargo handling machine 12 of the second example, the method using the operation direction detection sensor does not have a closed loop, so the operation is stable. It is necessary to change the detection method and structure of the sensor 18.

  In addition, when the numerical value output from the operation force detection sensor 18 or the load sensor is an analog value, the control circuit 131 needs to read through the A / D converter, but it is not always necessary to know only the direction of the operation force. It need not be an analog value.

Although the above has described the operation for reducing the operating force and the structure for the operation, the cargo handling machines 11 and 12 of the present invention have not only that but also, for example, an up switch and a down switch, and if the up switch is pressed, When the internal pressure of the cylinder 121 exceeds the load balance pressure P ₂ , the cargo handling object 119 is lifted and the lowering switch is pressed, the internal pressure of the cylinder 121 is set to a magnitude less than the load balance pressure P ₂ , 119 can be taken down.

External view of prior art and cargo handling device of the present invention Control block diagram of prior art cargo handling machine Control block diagram of cargo handling machine of first example of the present invention Control block diagram of cargo handling machine of second example of the present invention The figure for demonstrating an example of the operation force detection sensor Timing chart for explaining the relationship between the pressure signal of the prior art cargo handling machine and the cylinder internal pressure Timing chart for explaining the relationship between the pressure signal and the cylinder internal pressure of the cargo handling machine of the first example of the present invention Timing chart for explaining the relationship between the output signal, pressure signal and cylinder internal pressure of the operating force detection sensor of the cargo handling machine of the second example of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 12 ... Load handling machine 18 ... Operation force detection sensor 21 ... Auxiliary sensor 115 ... Arm 119 ... Load handling 121 ... Cylinder 131 ... Control circuit 132 ... Pressure control apparatus

Claims (11)

An arm that lifts the cargo,
A cylinder attached to the arm;
A pressure control device connected to the cylinder, supplying and exhausting gas in the cylinder, and setting the pressure in the cylinder according to an input pressure signal;
A control circuit for outputting the pressure signal to the pressure control device;
Have
When the pressure signal indicating the load balance pressure corresponding to the weight of the cargo handling object is output from the pressure control device, the ascending force generated by the pressure in the cylinder and applied to the cargo handling object via the arm; And a descending force generated by the weight of the cargo handling material, the cargo handling material is stationary in the vertical direction, and when the operation force is applied to the cargo handling material, a balance state is formed in which the cargo handling material can be moved in a desired direction. A cargo handling machine,
The control circuit detects whether the operating force has an upward component or a downward component, and changes the pressure signal to increase the cylinder pressure if it has an upward component. A cargo handling machine configured to generate an upward assisting force and to generate a downward assisting force by reducing the pressure of the cylinder when it has a downward component. An auxiliary sensor for measuring the pressure in the cylinder is provided;
2. The control circuit according to claim 1, wherein the control circuit detects increase / decrease in pressure in the cylinder from a measurement result of the auxiliary sensor, and determines whether the operation force has an upward component or a downward component. Cargo handling machine.   The cargo handling machine according to claim 2, wherein the control circuit is configured to extinguish the auxiliary force when a predetermined auxiliary force generation time elapses after the auxiliary force is generated. An operation force detection sensor for detecting a direction of the operation force is provided between the arm and the cargo handling material,
The cargo handling machine according to claim 1, wherein the control circuit determines whether the operation force has an upward component or a downward component based on a signal input from the operation force detection sensor.   The cargo handling machine according to claim 4, wherein when the disappearance of the operation force is detected by the operation force detection sensor, the pressure signal is returned to a load balance pressure.   The cargo handling machine according to any one of claims 1 to 5, wherein a magnitude of the auxiliary force is set to a magnitude capable of maintaining the stationaryness in the vertical direction. An arm that lifts the cargo,
Using a cargo handling machine having a cylinder attached to the arm,
The pressure in the cylinder is set to a load balance pressure corresponding to the weight of the cargo handling material, and the lifting force applied to the cargo handling material via the arm by the pressure in the cylinder and the descent caused by the weight of the cargo handling material Balancing the force, the loading material is stationary in the vertical direction, and when an operating force is applied to the loading material, the conveying method forms a balanced state in which the loading material can be moved in a desired direction,
It is detected whether the operating force has an upward component or a downward component, and if it has an upward component, the pressure of the cylinder is increased to generate an upward assisting force on the cargo item. In the case of having a component in the downward direction, the conveying method of reducing the pressure of the cylinder and generating a downward auxiliary force on the cargo item.   The transport method according to claim 7, wherein when the disappearance of the operating force is detected, the auxiliary force is extinguished.   The conveyance method according to claim 7, wherein a component of the operating force is detected from a pressure change in the cylinder.   The conveyance method according to claim 9, wherein the auxiliary force is extinguished after a predetermined auxiliary force generation time elapses.   The conveyance method according to any one of claims 7 to 10, wherein the magnitude of the auxiliary force is set to a magnitude that maintains the stillness in the vertical direction.

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