JPH0120092B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention The present invention relates to a rear door opening/closing device for a dump truck that is simple, reliable, economical, and extremely efficient.

Normally, the rear door of a dump truck is rotatably attached to both the left and right edges of the loading platform, and when the loading platform is raised during cargo dumping, the opening/closing device is activated, and the key is released. The rear door can now be opened. For this reason, if the cargo is gravel or sand, there is no particular problem in unloading, but if the cargo is larger than the height of the rear door, such as large stones, large tree roots, or waste materials, If the cargo is heavy, it will not only get stuck on the top of the rear door, making dumping operations difficult, but also cause the cargo to crash into the rear door and damage it, causing the weight of the cargo stuck on the rear door to be damaged. This may cause the front of the vehicle to stand on its head, creating the risk of it falling over. Especially when the dump site is on a high road side, it is not uncommon for the vehicle to fall onto the road, and this type of accident is a constant occurrence. In addition, even if the load is easy to dump, such as gravel or sand, the load on the ground can get caught in the rear door, so it is necessary to move the dump truck forward two or three times little by little until the load is completely dumped. This is an inconvenience. In order to prevent damage to the rear door and accidents like this, or where the dumping area is so small that dumping cannot be done without moving the dump truck, it may be advisable to remove the rear door before starting the dumping operation. This results in a decrease in the efficiency of dumping operations.

The applicant aims to provide a simple and economical rear door opening/closing device for a dump truck that prevents the above-mentioned dangers, eliminates damage to the vehicle body, and can be expected to improve the efficiency of dumping operations.

Embodiments of the present invention will be described below with reference to the drawings.

(2) Regarding the structure of the invention The present invention has the following structure in order to achieve the above object. Embodiments will be described below with reference to the drawings.

As shown in FIG. 1, in the present invention, a rotary arm 4 is attached to a bottom plate 3 having a mounting hole 7 so as to be movable up and down. Reference numeral 8 denotes the rotation axis, and a support arm guide/support frame 6 is integrally formed at the tip of the rotation arm 4. Reference numeral 9 denotes a reinforcing side plate, which integrally constitutes the support arm guide/support frame 6 and the rotating arm 4. Note that when constructing the support arm guide/support frame 6 at the tip of the rotary arm 4, if it is firmly fixed by welding or the like, there is no need to provide the reinforcing side plate 9; Since it also has the effect of preventing the intrusion of earth and sand and preventing the rotating arm 4 from curving, the provision of the reinforcing side plate 9 is more effective for the device as a whole. Reference numeral 10 denotes a bearing for the rotating shaft 8, which is integrally provided on the bottom plate 3. Next, the support arm 2 is mounted at an appropriate position on the bottom plate 3 so as to be able to move up and down, and 11 is a rotating shaft thereof, and 12 is a bearing, which is integrally provided on the bottom plate 3.

Note that, as in this embodiment, the length of the support arm 2 and the rotary arm 4 are the same, and the tip of the rotary arm 4 (the support arm guide/support frame 6) is located at the rear door 1.
If the support arm 2 is configured to be in an intermediate position when the door is closed, the position of the support arm guide/support frame 6 will be at the maximum open position of the rear door 1 (the position where the support arm 2 is perpendicular to the upper edge of the cargo bed side plate). Since it is the position of the door rotation bearing 14, the support arm 2 is 90
Rotating arm 4 relative to support 2 does not rotate more than ℃
The supporting force and anti-rolling force are maximized.

Next, the door rotation shaft 1 is attached to the top of the support arm 2.
Three bearings 14 are integrally provided, and the door rotation shaft 13 is attached thereto. Note that 15 is a rear door mounting bracket formed integrally with the door rotation shaft 13 (the first
(Fig. G) or constructed as a separate body (Fig. 1 H) and assembled. The rear door 1 is attached and fixed to this rear door mounting bracket 15.

The support arm 2 is slidably inserted into the support arm guide/support frame 6 of the rotation arm 4 and attached to the rotation shaft 11.

(3) Regarding the operation of the invention The present invention has the above configuration, and its operation will be described next.

As shown in FIG. 2, the bottom plate 3 of this device is placed on the upper edge 5 of the side plate of the loading platform with its tip aligned with the tip of the support arm 2, and fixed by screws 16 or the like.

Next, the rear door 1 is attached to the rear door mounting bracket 15. 17 is its mounting screw. When the cargo platform 23 begins to rise to dump the cargo 18, the catch 19 is released and the cargo 18 descends to the rear door 1.
, the rear door 1 rotates in the direction of opening (arrow 20) about the door rotation axis 13, and the greater the force of the load 18 to fall, the more the support arm 2 moves upward about the support arm rotation axis 11. (arrow 21)
make a rotational movement. In this case, the support arm 2 transmits the rotational movement as an impact to the tip of the rotational arm 4 within the support arm guide and support frame 6, so that the rotational arm 4 also rotates upward about the rotational shaft 8 (arrow 22). )do.

The maximum load opening width due to the upward rotation of the support arm 2 and the rotary arm 4 can be said to be when the support arm 2 is positioned perpendicularly to the upper edge 5 of the cargo platform side plate.

In any case, the rear door 1 rotates due to the impact force of lowering the load, and the support arm 2 and rotating arm 4 rotate upward to absorb the impact force and widen the opening for the load to drop.

(4) Effects of the Invention Since the present invention has the above-described structure and operation, even if the cargo 18 hits the rear door 1 with force, the rear door 1, the support arm 2, and the rotating arm 4 will not move around the rotating shafts 13, 11, respectively. , 8, and absorbs the impact force of the cargo on the rear door 1 to prevent damage to the rear door 1.Furthermore, since the cargo drop port is wide open, even large cargoes 18 can easily reach the ground. Since the rear door 1 does not interfere with the lowering of the load as it is being dumped, it is possible to unload the load at a position further away from the loading platform than before, and there is no need to move the dump truck forward for unloading, making the work easier. Efficiency will also be further improved. Next, since the support arm 2 suspends the heavy rear door 1 from its tip, it normally sways when it rotates upward, but in the present invention, the rotation arm 4 is provided to support the rear door 1. This has the effect of supporting the arm 2 more firmly and preventing it from rolling. Furthermore, it is possible to avoid the conventional case where the load is supported by the rear door 1 and the load is concentrated on the tail of the loading platform, so accidents such as tipping over of the dump truck can be prevented, and many other effects are achieved.

[Brief explanation of drawings]

The drawings show the embodiment. Figure 1A is a right side view, B is a left side view, C is a plan view, D is an enlarged front view, E is a sectional view taken along line A-A in Figure C, and F is a support arm. It is an explanatory side view showing the state where it rotated upwards. The reinforcing plate is configured to be located on the inside surface of the loading platform. G is an enlarged explanatory side view of an embodiment in which the mounting bracket and the rear door rotation shaft are integrally formed, and H is an enlarged explanatory side view of an embodiment in which the mounting bracket and the rear door rotation shaft are provided separately and are freely rotatably combined. It is. FIG. 2 is an operational diagram of the device of the present invention installed on the loading platform of a dump truck, and the positions of the rear door, support arm, and rotating arm shown by dotted lines indicate the maximum opening position of the load drop port. 1... Rear door, 2... Support arm, 3... Bottom plate, 4... Rotating arm, 5... Upper edge of loading platform side plate, 6
...Support arm guide and support frame.

Claims (1)

[Claims] 1 A support arm 2 is attached to the tip of the bottom plate 3, which is configured so that it can be attached to the upper edge 5 of the side plate of the dump truck.
A rotary arm 4, which constitutes a guide and support frame 6, is mounted so as to be able to move up and down, and a support arm 2, which has a rear door 1 rotatably attached to its tip, is slid onto the support frame 6. A rear door opening/closing device for a dump truck, characterized in that the rear door opening/closing device for a dump truck is fitted into the interior so as to be movable and mounted on a bottom plate 3 so as to be movable up and down.