JPH0248264Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to a control device for a cargo handling vehicle.

(Prior art) Conventionally, a cargo handling frame is mounted on a vehicle chassis so that it can be raised and lowered or tilted, and containers placed on the chassis can be loaded and unloaded between the chassis and the ground, or the cargo handling frame can be tilted on the chassis. The vehicle is known.

However, there has been a problem in that immediately after the cargo handling frame of the cargo handling vehicle is returned to the chassis, an impact is generated due to the inertia of the cargo handling frame and the container, damaging various parts of the cargo handling vehicle, container, etc.

(Embodiment) The present invention has been made in view of the above points, and an embodiment of the present invention will be described below with reference to the drawings. L-shaped undulating frames 3 are provided at the front, and a container C can be loaded onto a cargo handling frame F made up of these frames 2 and 3.

The rear end of the tilting frame 2 is pivoted 4 to the rear end of the chassis 1 so as to be able to tilt rearward.
The letter-shaped undulating frame 3 is designed to be able to slide back and forth with respect to the tilting frame 2. That is, on the inner surface of the front part of the tilting frame 2, guide members 5, 5 having a U-shaped cross section are provided. fixed facing each other,
A crescent-shaped receiving member 6 fixed to the rear end of the L-shaped undulating frame 3 is slidably fitted into the guide members 5, 5.

On the other hand, the tip of a lift cylinder 7 whose base end is pivotally supported on the chassis 1 is connected to the center of the L-shaped undulating frame 3, and by expanding and contracting the lift cylinder 7, the lift cylinder 7 can be moved as described below. In addition, the L-shaped undulating frame 3 can be slid back and forth along the guide member 5 of the tilting frame 2, or the undulating frame 3 can be tilted integrally with the tilting frame 2.

A horizontal shaft 8 is rotatably supported in the middle of the tilting frame 2, and an arm 10 having a locking piece 9 fixed to its tip is fixed to the horizontal shaft 8.

One end of a connecting rod 11 is connected to the tip of the arm 10, and the other end is connected to the top of a triangular link 12 pivotally supported by the tilting frame 2.

The other top of the triangular link 12 is pivotally supported at the tip of a piston rod of a lock cylinder 13 that is pivotally supported on the tilting frame 2. By making the lock cylinder 13 expand and contract, the triangular link 1
2 and the connecting rod 11, the arm 10
can be moved up and down.

That is, by extending the lock cylinder 13, the arm 10 is held at the lower limit position, and when the lift cylinder 7 is extended in this state, the receiving member 6 at the rear end of the undulating frame 3 is moved to the horizontal axis 8. Guide member 5 of tilting frame 2 until contact
Then, as shown in FIG. 3, the cargo handling frame F is erected around the horizontal axis 8, and the container C can be unloaded onto the ground.

On the other hand, when the lock cylinder 13 is retracted, the arm 10 is held at the upper limit position, so that even if the lift cylinder 7 is subsequently extended, the undulating frame 3 will not slide, as shown in FIG. The undulating frame 3 and the tilting frame 2 can be tilted together on the chassis 1.

Note that 14 is a roller fixed to the four pivot axes, and slides on the floor surface of the container C.

Next, the hydraulic circuit will be explained with reference to FIG.

P is a tandem pump consisting of a first hydraulic pump Pa and a second hydraulic pump Pb, T is an oil reservoir, V1 is an electromagnetic control valve that controls the lift cylinder 7, and V2 is an electromagnetic control valve that controls the lock cylinder 13. , these electromagnetic control valves V1 and V2 are arranged in parallel to the discharge line of the tandem pump P. Further, each electromagnetic control valve V1, V2 is equipped with a spool operating solenoid.

On the other hand, on the discharge side of the tandem pump P, a high pressure relief valve R1 is branched and arranged to return the pressure oil to the oil reservoir T when the discharge pressure oil reaches the maximum setting pressure or higher, and a second pump Pb On the discharge side, there is a low pressure relief valve R that returns the pressure oil to the oil reservoir T when the discharge pressure oil reaches a set pressure or higher.
2 are arranged in a branched manner.

An electromagnetic on-off valve V3 is disposed in the vent circuit of this low pressure relief valve R2.

Note that Vc is a counterbalance valve.

Next, the electric circuit will be explained with reference to FIG. 5. B is a power source such as a battery, SW1 is a start switch when the cargo handling vehicle V is activated, and LS1 is a switch for returning the cargo handling frame F to the chassis 1 when the undulating frame 3 is raised or lowered. LS2 is a limit switch (electrical contact) that operates at the position just before it returns to the chassis 1 when the tilting frame 2 of the cargo handling frame F is tilted.SOL is the limit switch (electrical contact) that operates at the position just before it returns to the chassis 1. The solenoid SOL is energized only when the container C is loaded or laid down by the cargo handling frame F, and is not energized when the container C is unloaded or tilted.

The cargo handling frame F is provided with guide members 20 and 21 that turn on the limit switches LS1 and LS2, respectively. Limit switch in condition
It is arranged so that LS1 and LS2 are turned off.

(Function) As shown in Fig. 1, the undulating frame 3 of the cargo handling frame F on which the container C is mounted is laid down, and the
When attempting to return to the top, the limit switch LS is turned off just before the hoisting frame 3 returns to the top of the chassis 1.
1 is switched, the current from power source B is applied to solenoid SOL via limit switch LS1.

As a result, the electromagnetic on-off valve V3 is switched to the right position, so the vent circuit of the low pressure relief valve R2 is communicated with the oil reservoir T, and the set pressure of the low pressure relief valve R2 is set to zero. At this time, almost no oil is passed through the electromagnetic on-off valve V3, which merely maintains the back pressure of the low pressure relief valve.

Therefore, since the pressure oil from the second hydraulic pump Pb is returned to the oil reservoir T, the pressure oil supplied to the lift cylinder 7 is reduced to only the pressure oil from the first hydraulic pump Pa of the tandem pump P.

For this reason, the undulating frame 3 slowly contracts and returns to the vehicle chassis 1 gently, so that no impact is generated on the vehicle chassis 1 or the like.

Further, as shown in FIG. 2, the tilting frame 2
and the undulating frame 3 are tilted together, and the chassis 1
Even when the vehicle is returned to the upper position, the limit switch LS2 is switched to energize the solenoid SOL immediately before returning to the upper position, and thereafter the tilting frame 2 and the undulating frame 3 integrated with the tilting frame 2 slowly return to the top of the vehicle chassis 1 as described above.

Note that the limit switches LS1 and LS2 are removed from the guide members 20 and 21 when the undulating frame or tilting frame has returned to the chassis 1.
Switched to OFF state.

By the way, in the embodiment of the present invention, the cargo handling frame is composed of a tilting frame and a undulating frame, but in other embodiments, the cargo handling frame may be composed of only a tilting frame, or a cargo box can be mounted on this tilting frame. may be fixed.

Furthermore, when setting the discharge amount of the first hydraulic pump and the second hydraulic pump constituting the tandem pump, it is optional to set both to the same capacity or to set one larger than the other.

(Effects of the invention) As described above, according to the invention, the operating speed is slowed just before the cargo handling frame is returned to the vehicle chassis, so the cargo handling frame etc. can be returned to the vehicle chassis without causing a shock. damage can be reliably prevented.

The hydraulic pump is configured as a tandem pump, and a low-pressure relief valve that is remotely controlled by an electromagnetic on-off valve installed in the vent circuit is branched and connected to the discharge side of one of the hydraulic pumps.
Pressure oil from one hydraulic pump is always supplied to the actuator, almost no oil is passed through the electromagnetic on-off valve, and only the back pressure of the low-pressure relief valve is maintained, so it can be small and inexpensive.

Further, the electromagnetic on-off valve V3 can be installed at any location where there is sufficient space, and there is no need to extend the main oil passage piping.

[Brief explanation of the drawing]

Figure 1 is a diagram of the container loading/unloading state of the cargo handling vehicle upon return, Figure 2 is a diagram of the container tilting state of the cargo handling vehicle upon return, Figure 3 is a diagram of the container being unloaded onto the ground, and Figure 4 is its hydraulic pressure. Circuit Diagram FIG. 5 is an electrical circuit diagram. 1... Vehicle chassis, 7... Lift cylinder, V... Cargo handling vehicle, P... Tandem pump, F... Cargo handling frame, V3... Electromagnetic on-off valve.

Claims (1)

[Scope of utility model registration request] A cargo handling vehicle in which a cargo handling frame is mounted on a vehicle chassis so as to be able to be raised and lowered or tilted, a lift cylinder is connected between the cargo handling frame and the chassis, and the cargo handling frame can be raised and lowered or tilted by the expansion and contraction of the lift cylinder. , a tandem pump consisting of a first hydraulic pump and a second hydraulic pump is installed in order to supply pressure oil to the lift cylinder, and a vent circuit is connected to the discharge side of one of the hydraulic pumps of the tandem pump. A low-pressure relief valve that is remotely controlled by an electromagnetic opening/closing valve installed in the vehicle is branched and connected, and an electric contact is provided that operates immediately before the cargo handling frame returns to the vehicle platform, and the electromagnetic opening/closing is caused by the operation of the electric contact. By controlling the valve to open and allowing the pressure oil from one hydraulic pump to flow back into the oil reservoir, the discharge amount of the tandem pump is reduced.
A control device for a cargo handling vehicle, characterized in that the return operation of the cargo handling frame is performed slowly.