JPS5945531B2 - Dump truck loading platform “Kou” device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cargo platform lifting device for tilting a cargo platform in a dump truck.

Generally, in a dump truck, as shown in Fig. 4, a loading platform is placed on the vehicle frame a, and a pin C is attached at the bottom of the rear end so that it can be tilted.
A platform lifting device a is installed between the loading platform and the vehicle frame a, and the loading platform lifting device d has one end of a tension rod e connected to the vehicle frame a by a pivot. One end of the lift arm f is connected to the lower surface of the loading platform by a pivot shaft.The other ends of each of the lift arm f and the tension rod e are connected to the lower surface of the loading platform by a pivot shaft, and the vehicle frame a and the lift arm f are connected to each other by a pivot shaft. There is a single-stage hydraulic cylinder g between
are connected, and the connecting portion of the single-stage hydraulic cylinder g to the vehicle frame a is located forward of the connecting portion of the tension rod e to the vehicle frame a, and the tension rod e and the single-stage hydraulic cylinder g are at an intersection. The loading platform is configured such that the loading platform is tilted by the expansion and contraction movement of the single-stage hydraulic cylinder g.

Since the loading platform hoisting device d is retracted between the vehicle frame a and the loading platform, the folded height is severely restricted during storage.
It is necessary to ensure a sufficient stroke to tilt the loading platform up to 100°, and the single-stage hydraulic cylinder g has no choice but to have a long length when retracted.

Then, as mentioned above, the intersection between the tension rod e and the single-stage hydraulic cylinder g is placed between the vehicle frame a and the loading platform, which has a height restriction, and the loading platform has no choice but to take a nearly horizontal position when retracted. and the lift arm f deviates forward from the connection point.

Therefore, the lifting blade of the loading platform acts in the direction of the extension line connecting the intersection of the tension rod e and the single-stage hydraulic cylinder g and the connection point between the loading platform and the lift arm f. Since the direction is inclined with respect to the loading platform, a large cylinder output is required (see Figure 5), and the required strength of both the single-stage hydraulic cylinder g1, lift arm f, and tension rod e is large. However, there are problems such as increased weight.

The present invention has been made in view of these points, and by connecting a multi-stage hydraulic cylinder instead of the conventional single-stage hydraulic cylinder between the vehicle frame and the lift arm, the length when retracted can be reduced. In order to allow the multi-stage hydraulic cylinder and the tension rod to intersect with each other within the loading platform tilting range (maximum tilt angle of 55° to 60°), and to effectively use the lifting blade at the initial stage of loading platform tilting, which requires the maximum lifting blade, the above-mentioned method is adopted. To provide a dump truck platform hoisting device in which the intersection of a multi-stage hydraulic cylinder and a tension rod is located almost vertically below a connection point between a lift door arm and a platform, thereby reducing 1 drive output and saving energy. .

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, 1 is a dump truck, and a loading platform 3 is mounted on a vehicle frame 2 with pins 4 at the bottom of the rear end so as to be tiltable.
A loading platform lifting device 5 is installed between the loading platform 3 and the vehicle frame 2 to tilt the loading platform 3 rearward.

The platform lifting device 5 is composed of a tension rod 6, a lift arm 7, and a multistage hydraulic cylinder 8, and one end of the tension rod 6 is rotatably attached to a bracket 9 provided in the center of the vehicle frame 2 by a pivot shaft 10. The lift arm 7 is formed into a triangular shape with two acute angle parts and one obtuse angle part, and is rotatably connected to the lower part of the loading platform 3 at one acute angle part by a pivot shaft 11, and the other The acute angle part of the tension rod 6 and the other end of the tension rod 6 are rotatably connected by a pivot 12, and the tension rod 6 and the lift arm 7 are provided so as to be bent forward as the loading platform 3 is tilted. There is.

The multi-stage hydraulic cylinder 8 is installed between the vehicle frame 2 and the lift arm 7, and the base end of the cylinder case 13 of the multi-stage hydraulic cylinder 8 is rotated by a pivot shaft 14 on a bracket 9 provided on the vehicle frame 2. They are movably connected, and the connecting portion is located forward of the connecting portion of the tension rod 6 to the bracket 9.

Furthermore, an internal cylinder 15 is provided inside the cylinder case 13.
is inserted into the internal cylinder 15, and a plunger 16 is inserted into the inner cylinder 15.
is fitted and inserted, and the tip of the plunger 16 is rotatably connected to the obtuse angle part of the lift arm 7 by a pivot 17,
The multi-stage hydraulic cylinder 8 is connected to the loading platform 3 as shown in FIG.
The tension rod 6 is always intersected within the tilting range (maximum inclination angle of 55° to 60°), and the intersection p is substantially perpendicular to the pivot shaft 11 connecting the lift arm 7 and the loading platform 3 at the initial stage of the loading platform tilting. Located below, the lifting blade at the beginning of the loading platform tilting acts in the direction of the extension line (perpendicular to the loading platform 3) connecting the intersection p and the pivot 11, and at the same time, the initial posture of the multistage hydraulic cylinder 8 is changed from the conventional multistage type. The hydraulic cylinder g is placed in a more upright position than its initial position.

Therefore, when tilting the loading platform 3, the multi-stage hydraulic cylinder 8
As shown in FIG. 5B, the output is the highest at the initial stage of driving when the internal cylinder 15 is made to protrude, and thereafter decreases as the internal cylinder 15 protrudes, and then increases again when the plunger 16 protrudes. Although the output increases, it does not become larger than the output at the initial stage of driving, and the output also decreases as the plunger 16 protrudes and moves, reducing the maximum driving output by about 30% compared to the conventional one. Can be done.

As described above, according to the dump truck platform lifting device of the present invention, the multi-stage hydraulic cylinder connected between the vehicle frame and the lift arm stands up as much as possible with respect to the horizontal plane when contracted,
Since the lifting blade is most effectively applied perpendicularly to the loading platform, the output of the multistage hydraulic cylinder at the initial stage of operation can be significantly reduced compared to the conventional method, and energy can be saved. The output efficiency can be improved against the total load of the loading platform, and the multi-stage hydraulic cylinder,
The required strength of both the lift arm and the tension rod can be reduced, and the weight can be reduced.

[Brief explanation of the drawing]

1 to 3 illustrate embodiments of the present invention, FIG. 1 is a side view of the dump truck when the loading platform is stored, with a portion omitted, and FIG. 2 is a side view of the dump truck with the loading platform partially omitted. 3 is a schematic explanatory diagram showing the movement of the loading platform lifting device as the loading platform is tilted; FIG. 4 is a schematic explanatory diagram showing the movement of the loading platform lifting device as the loading platform is tilted. , FIG. 5 is a diagram showing a comparison of cylinder output changes with respect to the loading platform tilting angle in the loading platform lifting device of the present invention and the conventional loading device.

Claims (1)

[Claims] 1. A loading platform is tiltably supported on a vehicle frame, one end of a tension rod is connected to the vehicle frame, one end of a lift arm is connected to the lower part of the loading platform by a pivot, and each other of the lift arm and the tension lever is connected to the vehicle frame. one end of which is connected by a pivot;
Furthermore, a multi-stage hydraulic cylinder is connected between the vehicle frame and the lift arm, and a connecting portion of the multi-stage hydraulic cylinder to the vehicle frame is positioned forward of a connecting portion between the tension rod and the vehicle frame, and the multi-stage hydraulic cylinder The multi-stage hydraulic cylinder is connected to the lift arm so that the tension rod and the tension rod always intersect within the tilting range of the loading platform, and the intersection point is approximately perpendicular to the connection point between the lift arm and the lower part of the loading platform at least in the initial stage of tilting the loading platform. A dump truck platform lifting device characterized by being located at a lower position.