JPS58218434A - Device for automatically opening and closing rear flap door of dump car - Google Patents

Abstract

PURPOSE:To enhance the practicability of a rear flap door of a damp car in which the rear flap door is pivotally supported by a lower hinge so that it may be opened upward, by enabling the flap door to be automatically opened and closed upon a cargo box being titled and as well by enabling the flap door to be selectively held in its free condition. CONSTITUTION:When a cargo box 3 initiates its rearward tilting about a dump shaft 4, in its initial stage in which a bellcrank 8 is positioned in the vicinity of the shaft 4, a roller 8B is held in contact with the cam plate 26 of a cam part 10 with the roller being balanced with the force of a return spring 14 so that a rear flap door 5 is maintained in its closed condition. Then, the roller 8B is separated from the cam plate 26 when the tilting angle of the cargo box 3 exceeds a predetermined angle, so that an actuating lever 11 is pulled by the spring 14, and therefore, the flap door 5 is suspended downward by means of a four-joint link 20. Further, in order to keep the flap door 5 open even after the cargo box 3 being returned to its original position, the cam plate 26 is rotated rearward to a position 26' upon the tilting of the cargo box 3 and the flap door 5 is supported by a cable S.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a dump truck in which the rear door is hinged at the bottom and opens at the top, and the rear door is configured such that the opening angle of the rear door opens to a hanging position and an intermediate position when a cargo box is tilted. Regarding automatic door opening/closing devices.

Generally, as shown in Japanese Utility Model Publication No. 49-612, when the rear gate of a dump truck is of the automatic opening/closing type with a lower hinge and an upper opening, the rear gate and the opening/closing mechanism are linked, so the rear gate is The only way to get &2 by opening is to release the opening/closing mechanism with the box tilted.

The present invention can automatically open and close when the rear sliding door is hinged at the bottom and opens at the top, by tilting the cargo box until the opening angle of the rear sliding door is aligned with the bottom of the cargo box @ full hanging position. It also provides a mechanism that allows the rear door to be opened and closed without tilting the cargo box.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to one embodiment of the accompanying drawings.

A cargo box 6 is hung on a vehicle frame 1 of a dump truck so as to be tilted rearward with a main girder 2 as a center around a horizontal dump shaft 4 serving as a center for tilting the cargo box. The rear door 5 of the cargo box is pivotally supported around a horizontal pivot 7 provided at the rear of the cargo box 6 so as to be pivotable rearward from the rear end surface of the cargo box.

Next, to explain the opening/closing link mechanism of the rear gate 5 and the operating section connected thereto, a bell crank 8 as an operating section is located in front of the horizontal dump shaft 4 on the side of the main girder 2 and rotates around a pivot 9. The roller 8B at the tip of the roller 8B is placed in contact with a cam portion 10 provided on the side of the vehicle frame 1, and its upper end is pivotally connected to the tip of an operating lever 11.

The operating lever 11 has a spring buffer cylinder 13 in its suspension, and is pulled rearward by a return spring 14 suspended from the main girder 2.

The rear end of the operating lever 11 is pivotally connected to one end of a relay bell crank 16 whose center point is pivoted to the main girder 2 by a pin 15, and the other end of the relay bell crank 16 is pivotally connected to the front end of a connecting link 18. The other end of the connecting link 18 is pivotally connected to the front end of the floating link 20'A of the four-bar link 20 provided on the main girder 2, and the rear end of the floating link 20A is pivotally connected to one end of the connecting link 22. The other end is pivotally connected to a bracket 24 fixed to the rear gate 5.

Next, to explain the cam part 10 in detail, a pair of brackets 25 are fixed to the side of the vehicle frame 1, and a cam plate 26 is rotatably attached to the upper end of one of the brackets 25.
7, the cam plate 26 is placed horizontally on a pair of brackets 25, and the rollers of the actuating part are
(2) A selection operation can be performed between a position where the roller 8B contacts and a position where the roller 8B is rotated backward and does not contact the roller 8B.

It is also possible to connect a link mechanism (not shown) or a handle (not shown) to the cam plate 26 to perform selection operations from a remote location.

Next, to explain the operation of the present invention, when the cargo box 6 starts to tilt backward around the dump shaft 4, the bell crank 8 is initially close to the horizontal dump shaft 4, and the roller 8B
is balanced with the traction force of the return spring 14, and the cam portion 1
Since the opening/closing link mechanism remains in contact with the cam plate 26 of 0, the rear door 5 is kept closed.

When the tilt angle of the cargo box 6 exceeds a certain angle, the roller 8B separates from the cam plate 26 and is activated.) 1 The lever 11 is pulled by the return spring 14 and moves to the right in Fig. 1. Then, the floating link 20A of the four-bar link 20 moves to the left until the rear door 5 hangs down beyond the angle at which it lines up with the bottom of the cargo box (see Figure 2). When returning the door 6 from the tilted state, the rear door 5 is closed by operating in the opposite manner to the above.

In addition, if you want to keep the rear door 5 open even after the cargo box 6 returns, the cam plate 10 of the cam part 10 can be
It is sufficient to return the cargo box 3 after rotating the cargo box 6 backward as shown by the arrow (see the two-dot chain line 26), and as the cargo box 6 descends, the bell crank 8 of the actuating part approaches the cam part 10. Since the cam plate 26 does not exist in the range where the roller 8B contacts, no external force is applied to the roller 8B, and the opening/closing link mechanism and the rear sliding door are held in a free state. Therefore,
After the cargo box 6 has returned to its original position in this state, the rear door 5
Chain 1. It is held by connecting it to the cargo box 6 with cables S such as wires.

As described above, according to the present invention, in the lower hinge, upper opening automatic opening/closing system in which the rear gate is pivoted at the bottom of the rear end of the dump truck, the actuating section connected to the opening/closing link mechanism
It can be in contact with or not in contact with the cam part installed on the vehicle frame, and can be used as a regular 6 dump truck, and can also be used to transport cargo longer than the length of the box, making it multifunctional. It is something that can be measured.

[Brief explanation of the drawing]

FIG. 1 is an overall side view of an embodiment of the present invention, and FIGS. 2 and 6 are diagrams showing operating states. 1...Car frame, 6...Logging box, 5...Rear door, 7...Pivot, 8...Bell crank (operating part), 10...Cam Department. Output η11 people

Claims (1)

[Claims] A rear sliding door pivotally supported at the bottom of the rear end of a dump truck, an opening/closing link mechanism connected to the rear sliding door, an actuating part connected to the opening/closing link mechanism, and an actuating part provided on the vehicle frame to which the actuating part can come into contact. An automatic rear door opening/closing device for a dump truck, comprising a cam part, the cam part being movable between a contact position with an operating part and a non-contact position.