JPH0116697B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention is characterized in that the locking pin is held between a holding piece and a hook that receive the locking pin at the bottom of the sliding door, and in this state, the locking pin is centered. When the fan door is moved downward,
This dump truck prevents the hook from disengaging from the locking pin due to the impact, and also prevents the door from falling even when the cargo box is dumped with the door moved downward. It is used in the field of safety devices for sliding door opening/closing devices.

(b) Prior Art Conventionally, as shown in FIG. 6, in a fan door opening/closing device in which a buffer cylinder 03 containing a spring is provided in the middle of a rod 02 between an operating arm (not shown) and a hook 01, If the upper hinge (not shown) is removed and the sliding door 04 is moved downward around the lower locking pin 05, the sliding door 04 will violently collide with the lower end of the cargo box 06 due to its own weight. However, a moment acts on the lower part of the sliding door 04 centering on the collision part 07, and a large force acts on the hook 01 in the opening direction.

At this time, the spring in the buffer cylinder 03 is compressed by the acting force, the distance between the operating arm and the hook 01 is lengthened, and the hook 01 is rotated to the opening side, and the hook 01 is released from the locking pin 05. This causes the fan door 04 to fall.

In this state, if the sliding door 04 were to fall onto the feet of the worker, a serious accident would occur.

Furthermore, with the sliding door 04 moved downward, the cargo box 06
When dumped as shown in Figure 7, the hook is 0.
1 rotates as the cargo box rises, and the locking pin 05 disengages from the hook 01, so that the sliding door 04 falls due to its own weight. Therefore, there was a drawback that the heavy fan door 04 had to be lifted and installed.

(c) Problems to be Solved by the Invention The present invention has been made to solve the above-mentioned problems, and includes providing an engaging hole communicating with the fitting hole in the holding piece that receives the locking pin. When the sliding door is moved downward around the lower hinge part, the locking pin is fitted into the engagement hole to prevent the locking pin from coming off from the engagement hole of the holding piece. purpose.

(d) Means for solving the problem The feature of the present invention is that a hook that engages with a locking pin provided on a mounting piece at the bottom of the sliding door is rotated as the cargo box is raised and lowered, and the sliding door is closed. is opened and closed centering on the upper hinge part, while the lower hinge part which holds the locking pin between the holding piece provided on the cargo box side and having a fitting hole for receiving the locking pin and the hook. In a tipper door opening/closing device for a dump truck which allows the tipper door to be moved downward from the center, there is a locking hole located at the bottom of the fitting hole in communication with the fitting hole and having a size that allows the locking pin to fit therein. A hole is provided in the holding piece, a cam portion of an appropriate shape is provided in the locking pin, and when the fan door is rotated about the lower hinge portion in correspondence with the lower part of the cam portion, a lower contact piece capable of moving the locking pin up and down by abutting a cam portion and fitting the locking pin into the engagement hole; and at least when the locking pin is fitted into the fitting hole; The present invention provides a safety device for a swing door opening/closing device for a dump truck in which an upper abutting piece is provided on the cargo box side, and an upper abutting piece that the upper surface of the cam portion abuts to restrict upward movement of the locking pin.

(e) Example An example will be explained below with reference to the drawings. 1 is a cargo box that tilts rearward around a hinge part 3 at the rear end of a chassis frame 2; 4 is a cargo box provided at the upper part of the rear end of the cargo box 1; This sliding door swings around a removable upper hinge part 5, and a hook 7 is attached to the lower part of the sliding door 4, which fits into a holding piece 6 provided on the rear surface of the lower part of the cargo box 1. The locking pin 8 to be matched is attached to a pair of left and right mounting pieces 9, 9.
The holding piece 6, the hook 7, and the locking pin 8 constitute a lower hinge portion 10.

The holding piece 6 is formed with a fitting hole 11 that opens rearward, and the fitting hole 11 has a size that allows the locking pin 8 to fit into the fitting hole 11 and is in communication with the fitting hole 11 at the bottom of the lower surface of the fitting hole 11. An engagement hole 12 is formed therein.

A cam portion 13 such as a cam piece is fixed to the locking pin 8, and the protrusion amount of the cam piece 13 is larger than the locking pin 8.
It has a generally circular shape that gradually becomes larger from the upper surface to the lower surface.

Reference numeral 14 denotes a lower abutting piece provided at the lower part of the rear surface of the cargo box side, and this lower abutting piece 14 touches the cam portion 13 when the rear opening of the cargo box 1 is closed by the fan door 4 shown in FIG. The locking pin 8 is located in the fitting hole 11 in contact with the locking pin 8 . When the fan door 4 moves downward by 180 degrees from this state, the locking pin 8 moves downward due to the weight of the fan door 4 while maintaining contact between the cam part 13 and the lower contact piece 14. Fits into the engagement hole 12.

Reference numeral 15 denotes an upper abutting piece attached to the packing box side in the same way as the lower abutting piece 14, and at least when the locking pin 8 is fitted into the engagement hole 12, it comes into contact with the upper surface of the cam part 13 and is locked. The upward movement of pin 8 is restricted.
The hook 7 is pivotally supported 16 at the bottom rear end of the cargo box 1.

Reference numeral 17 denotes an operating arm 18 that is pivotably supported at the bottom of the cargo box 1 in front of the hook 7 so as to be able to swing back and forth.The operating arm 17 and the hook 7 are connected by a rod 21 that has a buffer tube 20 inside a spring 19 interposed therebetween. has been done.

Reference numeral 22 denotes a guide piece for guiding the roller 23 at the tip of the operating arm 17, and is attached to the chassis frame 2 side.

Incidentally, 24 is a spring connected to the rod 21 side and the cargo box 1 side to spring the rod 21 backward.

The present invention has the above-described structure, and its operation will now be explained. First, when the cargo box 1 is raised, the roller 23 at the tip of the operating arm 17 separates from the guide piece 22, so the force of the spring 24 causes the rod 21 to move away from the guide piece 22.
is pulled rearward, whereby the hook 7 and the locking pin 8 are disengaged, and the sliding door 4 swings rearward about the upper hinge portion 5, and the sliding door 4 is opened.

On the other hand, with the locking pin 8 held between the holding piece 6 and the hook 7, the upper hinge part 5 is removed and the fan door 4 is removed.
When the sliding door 4 is rotated approximately 180 degrees, it collides with the lower end of the cargo box 1 as shown in FIG. 4.

At this time, the attachment portion 9 of the locking pin 8 is attached to the collision portion 2.
A clockwise moment acts around 5,
This force acts on the tip of the hook 7 as a large force.

When this acting force is generated, the spring 19 in the buffer cylinder 20 is compressed and the distance between the operating arm 17 and the hook 7 is lengthened, so the hook 7 is rotated in a direction to disengage from the locking pin 8. However, at this time, the locking pin 8 moves downward while maintaining the contact between the cam part 13 and the lower contact piece 14, and the lower part of the locking pin 8 is fitted into the engagement hole 12. At this time, since the cam part 13 moves upward, the cam part 13 abuts on the upper abutting piece 15, and the locking pin 8
This restricts the upward movement of the locking pin 8, thereby preventing the locking pin 8 from coming off the fitting hole 11.
The door 4 will no longer fall.

Furthermore, if the sliding door 4 is moved downward around the lower hinge part 10 and the cargo box 1 is dumped in this state, the hook 7 will be rotated in the opening direction as shown in FIG. At this time as well, the locking pin 8 is fitted into the engagement hole 12 and the cam part 13 is in contact with the upper contact piece 15, so the locking pin does not come off from the fitting hole 11 and the sliding door 4 It is possible to reliably prevent the objects from falling.

Incidentally, in the present invention, the upper and lower abutting pieces 13 and 14 are attached directly to the cargo box 1, but they may be attached to the sides of the holding piece 6.

(f) Effects of the Invention As described above, the present invention allows the cam portion provided on the locking pin to contact the upper and lower contact pieces provided on the cargo box side when the sliding door is moved downward, and By moving the locking pin downward and fitting it into the engagement hole, there is no impact when the sliding door is moved downward, and even if the cargo box is dumped with the sliding door being moved downward. ,
The locking pin does not come out of the fitting hole of the holding piece.
This makes it possible to reliably prevent the sliding door from falling.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the overall view of the sliding door opening/closing device of the present invention, Fig. 2 is a sectional view when the opening of the cargo box is closed with the sliding door, and Fig. 3 is a rear view of Fig. 2. , 4th
The figure is a sectional view when the sliding door is moved downward, Figure 5 is a sectional view when the sliding door is moved downward to dump the cargo box, and Figures 6 and 7 are the conventional sliding door. It is a sectional view showing a switchgear. 1 is the packing box, 4 is the sliding door, 5 is the upper hinge part, 6
1 is a holding piece, 7 is a hook, 8 is a locking pin, 10 is a lower hinge part, 11 is a fitting hole, 12 is an engagement hole, 1
3 is a cam portion, and 14 is an abutment piece.

Claims (1)

[Claims] 1 The hook that engages with the locking pin provided on the mounting piece at the bottom of the sliding door is rotated as the loading box is raised and lowered, and the sliding door is opened and closed around the upper hinge part. Opening/closing of a swing door of a dump truck in which the swing door can be moved downward around a lower hinge part that holds a locking pin between a holding piece having a fitting hole for receiving a locking pin and the hook. In the device, the holding piece is provided with an engaging hole communicating with the fitting hole at the lower back of the fitting hole and having a size that allows the locking pin to fit therein, and the locking pin has an appropriately shaped engaging hole. A cam part is provided, and when the fan door is rotated about the hinge part at the bottom corresponding to the lower part of the cam part, the cam part contacts and moves the locking pin up and down, thereby locking the door. A lower contact piece into which the pin can be fitted into the engagement hole; and at least when the locking pin is fitted into the fitting hole, the upper surface of the cam portion comes into contact to restrict upward movement of the locking pin. A safety device in a dump truck fan door opening/closing device, which is provided with an upper contact piece and each on the loading box side.