JPS6229258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an automatic tailgate opening/closing method for a dump truck with a lift device, which is capable of opening and closing the tailgate that constitutes a part of the lift device in relation to the tilting of a cargo box. It is related to the device.

In general, in this type of dump truck equipped with a lift device, when dumping the loaded items in the cargo box, conventionally the tailgate, which is stored vertically, is opened upwards and then opened horizontally to discharge the cargo. Since the loaded object is ejected by sliding on the upper surface of the tailgate, the sliding surface becomes longer and ejection performance deteriorates.

In addition, there was a problem that the tip of the tailgate was close to the ground, making it impossible to completely eject the loaded items.To solve this problem, the vertical tailgate was opened downward, but it was difficult to open and close the tailgate. The device was operated manually as before.

Therefore, if the operating lever for operating the opening/closing device is erroneously operated, a problem arises in which the cargo box is dumped while the tailgate remains closed.

The present invention solves the conventional problems by automatically opening and closing the tailgate in conjunction with the lifting and lowering of the cargo box.

Examples of the present invention will be described below with reference to the figures.
1 is the vehicle body, 2 is a subframe on the vehicle body 1, and 3 is a cargo box mounted on the subframe 2. This cargo box 3 can be dumped rearward around the hinge part 4 at the rear of the subframe 2. ing.

5 is a lift device attached to the rear end of the cargo box 3;
This lift device 5 will be explained below. A mounting bracket 6 is provided at the rear end of the main girder 3' of the cargo box 3, and this mounting bracket 6 has a connecting piece 8 whose upper portion is swingable back and forth about a shaft 7. It is pivoted. The base of an upper link 9 is integrally supported with the shaft 7 on the shaft support 7 of the connecting piece 8, and the base of a lower link 10 is pivotally supported 11 on the lower part of the connecting piece 8.

The tip of the upper link 9 and the lower link 10
The tip of the is mounted on a vertical mounting column 12 with pivot supports 13 and 14.
and the connecting piece 8 and the pair of links 9 and 10.
The mounting support 12 forms a parallel link mechanism. Reference numeral 15 denotes a stopper fixed to the mounting bracket 6 that restricts forward swinging of the connecting piece 8 and holds the connecting piece 8 vertically.

16 is a rotatable shaft support 1 at the bottom of the mounting column 12.
7 tailgate, this tailgate 16
is held substantially horizontally by a bendable holding rod 18 connected between the upper part of the mounting column 12 and the middle part of the side surface of the tailgate 16, and when the tailgate 16 is stored vertically, the rear surface of the cargo box 3 cover.

An arm 1 is attached to the shaft 7 that pivotally supports the upper link 9.
A piston rod of a hydraulic cylinder 20, which is pivotally supported by the mounting bracket 5, is connected to the tip of the arm 19, and the expansion and contraction of the hydraulic cylinder 20 operates the parallel link mechanism, and the tail The gate 16 can be raised and lowered.

Reference numeral 21 indicates a lashing means for lashing the tailgate 16 to the mounting support 12 when the tailgate 16 is stored vertically. It is comprised of a locking hole 23 that is bored in the upper end of the support column 12 and engages a locking pin 22.

24 indicates a hydraulic power unit incorporating an electric motor, a gear pump, an oil tank, a valve, etc. Next, the tailgate 1 which is the main part of the present invention
To explain the automatic opening/closing device 6 with reference to FIGS. 3 to 5, 25 indicates an engagement pin fixed to the base end of the tailgate 16, and 26 indicates an engagement pin fixed to the rear end of the main spar 3 of the cargo box. The hook 27 is rotatably supported, and the relationship between the engagement pin 25 and the hook 26 is as shown in FIG. 25, the hook 26 can close the base of the tailgate 16, and when the tailgate 16 is rotated horizontally rather than vertically, the engaging pin 25 moves to the upper position and the tailgate 16 is closed. There is no interference between the engagement pin 25 and the hook 26 when the hook 26 is raised or lowered.

Reference numeral 28 designates an operating arm 29 that is pivotably supported on the main girder 3 appropriately forward of the hook 26, and a roller 30 provided at the lower end of this operating arm 28 can come into contact with a guide plate 31 fixed to the subframe 2. The upper end of the operating arm 28 is also connected to the hook 26 by a transmission member 32. 33
is connected between the transmission member 32 and the main girder 3', and the hook 2
6 is a spring that urges the engagement pin 25 in a direction to release the engagement pin 25.

The present invention has the above-described configuration, and now to explain the case where cargo is loaded into the cargo box 3 using the tailgate 16, the vertical tailgate 16 is first rotated until it becomes horizontal. At this time, the engagement pin 25 fixed to the base of the tailgate 16 moves upward as shown in FIG. After that, when the hydraulic cylinder 20 is expanded and contracted to rotate the upper link 9, the lower link 10 is constantly compressed, so the connecting piece 8 that supports the lower link 10 pivotably 11 comes into contact with the stopper 15. Therefore, tailgate 1
6 can be raised and lowered horizontally, and cargo on the ground can be loaded into the cargo box 3.

Next, when transporting the bulk goods loaded in the cargo box 3 by an appropriate means, the tailgate 16 is first raised to the highest position, and then the tailgate 16 is
6 is rotated about the shaft support 17 at the base until it becomes vertical, the engagement pin 25 moves downward and engages with the hook 26. At this time, if the locking pin 22 on the tailgate 16 side is fitted into the locking hole 23 on the mounting post 12 side, the upper part of the tailgate 16 is fixed to the mounting post 12, and the lower part of the tailgate 16 is on the cargo box 3 side. It will be fixed to the hook 26 of.

In the above state, the bulk items in the cargo box 3 are transported without spilling from the rear surface.

Next, when the cargo box 3 is tilted backward to dump and discharge the loose items in the cargo box 3, the operating arm 28 also rises as the cargo box 3 rises, and the operating arm 28 moves further away from the guide plate 31. When separated, the force of the spring 33 pulls the transmission member 32 backward, which causes the hook 26 to rotate and engage the engagement pin 25.
release the engagement.

When the cargo box 3 further rises, the upper link 9 is held in place by the hydraulic cylinder 20, and the other lower links 10, connecting pieces 8, and mounting struts 1
2 and the tailgate 16 are free, so as the cargo box 3 tilts backward, the tailgate 1
6 is integral with the mounting column 12, and swings rearward around the shaft support 14 at the tip of the upper link 9. As a result, the tailgate 16 on the rear surface of the cargo box 3 is automatically opened, and the inside of the cargo box 3 is Bulk materials are dumped. When the cargo box 3 is lowered after being discharged, the tailgate 16 swings forward due to its own weight as the cargo box 3 descends. On the other hand, when the actuating arm 28 comes into contact with the guide plate 31, the roller 30 of the actuating arm 28 rolls on the guide plate 31, so the actuating arm 28 rotates around the shaft support 29, causing the transmission member 32 to move forward. As a result, the hook 26 rotates and engages with the engagement pin 25 of the tailgate 16, thereby closing the tailgate 16.

As described above, the present invention fixes an engagement pin to the base of the tailgate rotatably supported on a mounting column, and engages the engagement pin with a hook that rotates in relation to the lifting and lowering of a cargo box. Therefore, during cargo handling when the tailgate is horizontal, the tailgate can be raised and lowered freely without interfering with the hook, and when the tailgate is vertical during transportation, the engaging pin and the hook are engaged. The tailgate can be closed reliably.

Further, when the dump truck is discharged, the hook is automatically operated to release the engagement between the engagement pin and the hook, thereby ensuring that the tailgate can be opened.

[Brief explanation of the drawing]

Figures 1 and 2 are side views of the lift device attached to a dump cargo box, Figure 3 is a longitudinal sectional view showing the automatic tailgate opening/closing device which is the main part of the present invention, and Figure 4 is a side view of the lift device attached to the dump cargo box. Rear view showing installation, Figure 5 is the 3rd
FIG. 3 is a partially enlarged view showing the hook portion of the figure. 3 is a cargo box, 5 is a lift device, 9 is an upper link,
10 is a lower link, 12 is a mounting column, 16 is a tailgate, 25 is an engagement pin, and 26 is a hook.

Claims (1)

[Claims] 1. A connecting piece is provided at the rear end of the cargo box that can be tilted backwards, and the upper part is pivotally supported and the connecting piece pivots in the rearward direction. The base of the tailgate, which can cover the rear surface of the cargo box, is rotatably supported on the mounting column, and when the link is operated, the tailgate can be raised and lowered in a substantially horizontal position. and a lift device that swings the tailgate around a pivot at the tip of the upper link when the cargo box is tilted rearward with the tailgate stored vertically on the rear surface of the cargo box. In the dump truck, an engaging pin is fixed to the base of the tailgate, a hook that rotates in relation to the tilting movement of the cargo box is pivotally supported at the lower rear end of the cargo box, and the tailgate is held horizontally. A dump truck with a lift device, in which the engaging pin does not interfere with the hook when the dump truck is raised or lowered, and the engaging pin and the hook can be engaged with each other when the tailgate is placed vertically and stored at the rear of the cargo box. Automated truck tailgate opening/closing device.