JPS58180331A - Tilt angle limiting device of load case in dump truck - Google Patents

Abstract

PURPOSE:To prevent selective operation of a selector valve even for careless contacting of a link on a car body, by displaceably providing a selector head and its pressing member to a folding part of the folding link. CONSTITUTION:If a high pressure is applied to excessively extend an oil hydraulic cylinder 3, a root part link 21 and end part link 22 of a folding link 23 are placed in a linear state, and a selector head 26 and its pressing member 28 mounted to respective folding end parts 21a, 22a are contacted, further a roller 28a of the member 28 displaces a point end part 26a of the head 26 in the direction of an arrow mark 32. Accordingly, a selector valve 5 is pressed by a push pull cable 25 connected to the head 26 and the working fluid is switched to be fed back from a main selector valve to an oil tank via the valve 5, and the cylinder 3 is never further extended.

Description

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

2. Description of the Related Art There 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, as shown in FIG.

Briefly, a hydraulic cylinder 3 that telescopically expands and contracts is rotatably supported at both ends in a vehicle body 1 and a cargo box 2.
A cargo box movement angle regulating device W4 is provided near the container.

This is a switching valve 5 mounted on the vehicle body 1.
It has a switching lever 6 for switching the switching lever 6 and a wire 7 connecting the switching lever 6 and the cargo box 2. When the hydraulic cylinder 3 is extended and the cargo box 2 is tilted excessively, the wire 7, which is normally loose, is When pulled, the switching valve 5 is switched via the switching lever 6.

As shown in FIG. 2, the switching valve 5 is provided parallel to a path from the hydraulic pump 9 of the hydraulic circuit 8 to the hydraulic cylinder 3 via the check valve 10 and the main switching valve 11.

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 switches from the A position to the B position, the main switching valve 11 is activated. Oil directly into oil tank 1
2 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. There are no check valves, etc. installed near the oil painting.

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 made stationary, and maintenance and inspection of the hydraulic equipment such as the hydraulic cylinder 3 is performed on the vehicle body 1. In this case, 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 returns to the oil tank 12.

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, and it is possible to safely carry out work on a dump truck without switching the switching valve even if an operator accidentally touches the vehicle body. 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 bent link, and the switching head is moved. By switching the valve, it was possible to control excessive tilting of the cargo box caused by the hydraulic cylinder.

The present invention will be described 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 of which is rotatably supported at one end 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,
A bending link 23 is formed by the base link 2 and the tip link 22.

A bracket 24 as shown in FIG. One end of a push-pull cable 25 is introduced for remotely switching. This bushing pull cable 25 has a base link 2 in the bracket I.24.
A switching head 26, which is freely displaceable in the longitudinal direction of 1, is connected thereto.

On the other hand, a bracket 27 is fixed to the bent end 22a of the tip link 22, and a pushing member 28 is provided on the bracket 27 to protrude in the longitudinal direction of the tip link 22. Note that by supporting the roller 28a at the tip of the pushing member 2B, wear when contacting the switching head 26 can be avoided, as will be described later.

If 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, rotation in the directions of arrows 30 and 31 becomes possible, and the cargo box 2 By setting the center of rotation at the rear, right or left side of the vehicle body 1, the invention can also be applied to a three-turn dump truck that tilts in three directions: front and back and left and right.

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

First, the loading box 2 is not tilted excessively and the loading box 2 is not tilted excessively.
When it 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 in a separated state.

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

Next, when high pressure is applied to the hydraulic cylinder 3 and it expands excessively, the base link 21 and tip link 22 of the bending link 23 become straight, as shown in FIG. The mounted switching head 26 and the pushing member 28 come into contact, and the roller 28a of the pushing member 28 displaces the tip 26a of the switching head 26 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 is returned 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 the roller 28a rolls slightly on the tip 26a of the switching head 26.
Wear on the and pushing member 28 is avoided.

The bending link 23 operates as described above, while the cargo box 2
When working under a certain degree of tilting, the wire 7 has extremely high rigidity compared to the wire 7 described in the conventional example, and even if the worker touches the bent link 23, it will easily straighten. Never.

In addition, the switching head 26 is connected to the pushing member 2 as shown in FIG.
If the switching head 8 is housed in the bracket 24 to the extent that it contacts the switching head 8, it is possible to avoid contacting 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 displaceable switching head and its pushing member are provided for remote switching, so even if an operator inadvertently makes contact with the vehicle body, the switching valve will not switch and work can be continued safely. There is an effect that can be done.

[Brief explanation of the drawing]

FIG. 1 is an installation diagram of a conventional cargo box tilting angle regulating device, FIG. 2 is its hydraulic circuit diagram, FIG. 3 is a mounting diagram of the cargo box tilting angle regulating device in a dump truck of the present invention, and FIGS. Figure 5 is an enlarged view of the main part. ■...Vehicle body, 2...Loading box, 3...Hydraulic cylinder, 5...Switching valve, 20...Logging box tilting angle regulating device, 2
1... Base link, 22... Tip link, 21a,
22a... Refraction end portion, 23... Refraction link, 26.
...Switching head, 28...Pushing member patent applicant Kyokuto Kaihatsu Kogyo Co., Ltd. Agent Patent attorney Katsutoshi Yoshimura (and one other person) Figure 2

Claims (1)

[Claims] (1) In a dump truck having a hydraulic cylinder for tilting a cargo box on the vehicle body, a bending link consisting of a base link and a tip link whose respective ends are journalled on the cargo box or the vehicle body, and a bent link that is mounted on the vehicle body. a displaceable switching head mounted on the bent end of the base link for remotely switching the switching valve; and a pushing member protruding from the bent end of the tip link; When the cargo box tilts excessively due to the extension of A cargo box tilting angle regulating device for a dump trunk, characterized by being able to regulate tilting.