JPS6224291B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a cargo box tilting angle regulating device for a dump truck.

The first device is a tilting angle regulating device for a cargo box that can be tilted freely by a hydraulic cylinder on the body of a dump truck.
There is something like the one shown in the figure.

Briefly, a cargo box tilting angle regulating device 4 is installed near a telescopic hydraulic cylinder 3 whose both ends are rotatably supported in the vehicle body 1 and the cargo box 2.
is provided.

This includes a switching valve 5 mounted on the vehicle body 1, a switching lever 6 for switching the switching valve 5, and a wire 7 connecting the switching lever 6 and the cargo box 2. When the cargo box 2 tilts excessively, the normally loose wire 7 is pulled and the switching valve 5 is switched via the switching lever 6.

As shown in FIG.
It is provided parallel to the path leading to the hydraulic cylinder 3 via the.

When unexpected high pressure acts on the hydraulic cylinder 3, the wire 7 is pulled due to the excessive tilting of the cargo box 2, and when the switching valve 5 is switched from the A position to the B position, the main switching valve 11 The hydraulic oil is directly returned to the oil tank 12, so that the extension of the hydraulic cylinder 3 can be regulated.

By the way, when lowering the cargo box 2, the main switching valve 11 is switched from the C position to the D position, and the hydraulic cylinder 3 is automatically contracted by the weight of the cargo box 2. A check valve or the like is not provided near the oil supply/discharge port.

Therefore, after tilting the cargo box 2 to a certain extent, the hydraulic pump 9 is stopped with the switching valve 5 in the A position, the cargo box 2 is stopped, and the hydraulic equipment such as the hydraulic cylinder 3 is maintained on the vehicle body 1. When inspecting, if a worker accidentally hooks or pulls the loose wire 7, the switching valve 5 switches to the B position and the hydraulic oil in the hydraulic cylinder 3 flows into the oil tank 12. to return to.

As a result, there is a disadvantage that the cargo box 2 begins to descend, putting the worker on the vehicle body 1 in an extremely dangerous situation.

The present invention has been made in order to solve the above-mentioned problems.The present invention has been made in order to solve the above-mentioned problems. The purpose of the present invention is to provide a box tilting angle regulating device.

Its features include a bending link consisting of a base link and a tip link that are supported on the cargo box and the car body, and a switching valve mounted on the car body is remotely switched at the bending part of the bending link. A displaceable switching head and its pushing member are provided, and when the hydraulic cylinder is extended excessively, the pushing member pushes and displaces the switching head on the straight bending link, and the inside of the hydraulic cylinder is moved. By switching the switching valve that bypasses the hydraulic oil from the hydraulic pump flowing into the oil tank side, it is possible to prevent excessive tilting of the cargo box caused by the hydraulic cylinder.

The present invention will be explained in detail below based on examples thereof.

FIG. 3 is a diagram showing how the cargo box tilting angle regulating device 20 of the present invention is mounted on the vehicle body 1 and the cargo box 2.

A base link 21 and a tip link 22, each having one end supported by a shaft on the vehicle body 1 and the cargo box 2, are connected at their other ends in a bendable manner as shown by solid lines and imaginary lines, and these base links 21 and a tip link 22 are formed.

A bracket 24 as shown in FIG. 4 is fixed to the bent end portion 21a of the base link 21, which is the bent portion of the bent link 23, and the switching valve 5 mounted on the vehicle body 1 is remotely connected therein. One end of a push-pull cable 25 for switching is introduced. Connected to this push-pull cable 25 is a switching head 26 which is displaceable in the longitudinal direction of the base link 21 within the bracket 24.

On the other hand, at the bent end portion 22a of the tip link 22,
A bracket 27 is fixed, and a pushing member 28 is provided thereon projecting in the longitudinal direction of the front link 22. Note that a roller 2 is attached to the tip of this pushing member 28.
Bearing 8a avoids wear when contacting said switching head 26, as will be explained below.

Note that when the base link 21 and the tip link 22 are supported in the vehicle body 1 and the cargo box 2 by a universal shaft 29 as shown in the figure, arrow 3
It is possible to rotate in the 0 and 31 directions, and by setting the rotation center of the cargo box 2 to the rear, right or left side of the vehicle body 1, it can also be applied to a 3-turn dump truck that tilts in three directions: front, rear, left and right. be able to.

Since the present invention is configured as described above, it can be operated as follows.

First, when the cargo box 2 is not tilted excessively and the cargo box 2 is in a horizontal state, the bending link 23 is bent as shown in FIG. 4, and the switching head 26 and the pushing member 28 are bent. It is in a state of separation from.

Therefore, the switching head 26 is not displaced and the switching valve 5 is held at the A position shown in FIG. 1, so that the cargo box 2 does not descend.

Next, when high pressure is applied to the hydraulic cylinder 3 and it expands excessively, the bending link 2
The base link 21 and the tip link 22 of No. 3 are straight, and the switching head 26 attached to each bent end portion 21a, 22a contacts the pushing member 28,
In addition, the roller 28a of the pushing member 28 is connected to the switching head 2.
6 is displaced in the direction of arrow 32.

Therefore, the push-pull cable 25 connected to the switching head 26 is pushed, the switching valve 5 is switched to the B position, and the hydraulic oil from the main switching valve 11 returns to the oil tank 12 via the switching valve 5. Therefore, the hydraulic cylinder 3 will not extend any further.

At this time, the roller 28a slightly rolls on the tip 26a of the switching head 26, so that wear on the switching head 26 and the pushing member 28 is avoided.

While the bending link 23 operates as described above, when the loading box 2 is tilted to some extent and work is performed under it, the bending link 23 has extremely high rigidity compared to the wire 7 described in the conventional example, and the bending link 23 in the bent state Even if a worker touches it, it will not easily become straight.

Further, the bracket 24 is moved to such an extent that the switching head 26 comes into contact with the pushing member 28 as shown in FIG.
By storing the switching head 26 inside, it is also possible to avoid accidentally touching the switching head 26 itself.

As described in detail above, the present invention provides a bending link consisting of a base link and a tip link which are supported on a cargo box and a car body, and a switching valve mounted on the car body is attached to the bending part of the bending link. A movable switching head and its pushing member are provided for remote switching, so even if an operator inadvertently touches the vehicle, the hydraulic fluid from the hydraulic pump flowing into the hydraulic cylinder will not flow into the hydraulic cylinder. This has the effect of allowing work to be continued safely without switching the switching valve that bypasses the tank side. Moreover, since the rigidity of the cargo box tilting angle regulating device is extremely high compared to the wire described in the prior art, the device itself is also highly safe and reliable.

[Brief explanation of the drawing]

Figure 1 is an installation diagram of a conventional cargo box tilting angle regulating device.
FIG. 2 is a hydraulic circuit diagram thereof, FIG. 3 is a diagram showing how the cargo box tilting angle regulating device is installed in a dump truck according to the present invention, and FIGS. 4 and 5 are enlarged views of essential parts thereof. 1...Vehicle body, 2...Cargo box, 3...Hydraulic cylinder, 5...Switching valve, 9...Hydraulic pump, 12...
Oil tank, 20... Packing box tilting angle regulating device, 21...
...Base link, 22... Tip link, 21a, 2
2a... bending end portion, 23... bending link, 26...
...Switching head, 28...Pushing member.

Claims (1)

[Scope of Claims] 1. A dump truck having a hydraulic cylinder for tilting a cargo box on the vehicle body, comprising: a bending link consisting of a base link and a tip link whose respective ends are pivotally supported on the cargo box and the vehicle body; A movable switching head mounted on the bent end of the base link for remotely switching the switching valve mounted above, and a pushing member protruding from the bent end of the tip link. However, when the cargo box tilts excessively due to the extension of the hydraulic cylinder, the pushing member pushes and displaces the switching head on the bending link that has become straight, and the flow from the hydraulic pump is caused to flow into the hydraulic cylinder. A cargo box tilting angle regulating device for a dump truck, characterized in that excessive tilting of a cargo box caused by a hydraulic cylinder can be controlled by switching a switching valve that bypasses hydraulic oil to an oil tank side.