JPS589014B2 - Automatic rear door opening/closing device for three-turn dump truck - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic rear door opening/closing device for a three-turn dump truck.

Conventionally, the opening/closing device for the rear fan door in a three-turn dump truck was
Since the relative displacement between the sub-frame installed on the vehicle chassis and the cargo box was used, there was a problem in that it was necessary to provide a mechanism to hold the rear fan door closed to prevent the rear fan door from opening during side dumping. Ta.

Therefore, the present invention is designed so that the rear rotation shaft rotatably provided at the bottom of the cargo box rotates relative to the cargo box during rear dumping, and stops during side dumping. The object of the present invention is to provide an automatic rear sliding door opening/closing device for a three-turn dump truck, in which the rear sliding door is automatically opened by one relative rotation between the rear rotation shaft and the cargo box.

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

Reference numeral 1 designates a cargo box for a three-roll dump truck, with a pair of brackets 2 welded to the left and right rear portions of the bottom of the cargo box, and a rear rotation shaft 3.
is rotatably provided on the bracket 2.

A pair of protrusions 4, 4 are provided to protrude downward from each of the portions of the rear rotation shaft 3 located between the left and right brackets 2, and a retaining pin 5 is fixed to the distal end thereof in the front-rear direction.

On the vehicle body frame side, there are an engaging member 6 (fixed to both ends of the side frame 7) with which the engaging pin 5 engages, and a hook that locks the engaging pin 5 in the engaging member 6. A member 8 is provided corresponding to the engagement pin 5, and the engagement and disengagement between the hook member 8 and the engagement pin 5 is performed by a link mechanism or other control mechanism.

Although not shown, a pair of protrusions 4, 4 are provided at the left and right fronts of the bottom of the cargo box, respectively, to protrude downward, and an engagement pin 5 is fixed to the tips of the protrusions in the front-rear direction. An engaging member 6 that engages the engaging pin 5 and a hook member 8 that locks the engaging pin 5 in the engaging member 6 are provided.

During side dumping, the engagement between the engaging pin 5 and the hook member 8 is released at only two of the four locations on the front, rear, left and right sides, and during rear dumping, the engagement between the engaging pin 5 and the hook member 8 ( The rear rotation shaft 3 is fixed to the vehicle body frame by the rear left and right sides), and the cargo box 1 (bracket 2) is configured to rotate around the rear rotation shaft 3 as a central axis.

Reference numeral 9 denotes a rear sliding door of the cargo box 1, which is rotatably supported at the left and right ends of the upper part of the cargo box 1, and has pins 10 and 10 protruding from the left and right lower ends thereof, respectively.

On the other hand, at the rear of the cargo box 1, a locking hook 11.11 whose tip engages with the pin 10.10 is rotatably supported on the support bracket 12 in correspondence with the pin 10.10. .

A pair of cam plates 13.13 are fitted onto the rear rotation shaft 3, and an abutment pin 14.1 abuts against the cam plates 13.13.
A bell crank 15 having a number 4 is rotatably supported at the bottom of the cargo box.

The distal end of the bell crank 15 and the distal end of the locking hook 11 are connected by a fork member 16 and a spring cylinder 17.

The spring cylinder 17 includes a fixed rod 19 fixed to the cylinder 18 and a spring 2 housed inside the cylinder 18.
0, the movable rod 21 is biased to shorten the spring cylinder 17.

The distal end of the movable rod 21 and the distal end of the bell crank 15 are connected by a pin 22, and the distal end of the fixed rod 19 is screwed onto the base 23 of the fork member 16.

The fork portion 24 of the fork member 16 is pivotally supported by a pin 25 so as to sandwich the distal end of the locking hook 11.

26 is a protrusion provided on the cylindrical body 18;
A spring 27 is interposed between the locking hook 11 and the bracket 9, and urges the locking hook 11 in the direction of opening (counterclockwise).

Note that 28 is a protrusion of the cam plate 13, which abuts on the protruding pin 14 when the rear fan door 9 is closed.

Next, the operation of the above device will be explained. First, during rear dumping, the engaging pins 5 of the projections 4 at both ends of the rear rotation shaft 3 are locked with the engaging members 6 at both ends of the side frame 7 by the hook members 8. The rear rotation shaft 3 is secured to the vehicle body frame.

Next, by extension of a hydraulic cylinder (not shown), the cargo box 1
is rotated upward about the rear rotation shaft 3 as a central axis.

Accordingly, the bell crank 15 rotates backward while its contact pin 14 contacts the cam plate 13, and the spring cylinder 17
Then, the locking hook 11 is rotated via the fork member 16 in the direction in which the rear sliding door 9 is opened.

When the inclination angle of the cargo box 1 reaches approximately 15 degrees, the engagement between the locking hook 11 and the pin 10 is released, and the rear sliding door 9 is opened.

Also, when the cargo box 1 is rotated downward, the rear fan door 9 is automatically opened (locking hook 11 and pin 10
is engaged) and closed.

Since the present invention is constructed as described above, there is no need to provide a rear door closing position retaining mechanism for preventing the rear door from opening during side dumping, so the structure is simplified with fewer parts, and furthermore, Since the present invention has a structure in which the rotational torque of the bell crank 15 is not transmitted as rotational torque to the rear rotational shaft, the rear rotational shaft is not twisted during side dumping.
The rear rotation shaft does not need to have particularly high torsional rigidity.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is a sectional side view of a main part of the apparatus of the present invention, FIG. 2 is a plan view of the main part, and FIG. 3 is a rear view of the main part. 1... Packing box, 2... Bracket, 3... Rear rotation axis, 4
... Projection piece, 5 ... Engagement pin, 6 ... Engagement member, 7 ... Side frame, 8 ... Hook member, 9 ... Rear fan door, 1
0,22.25...pin, 11...locking hook, 12...
...Support bracket, 13...Cam plate 14...Abutment pin,
15... Bell crank, 16... Fork member, 17...
... Spring cylindrical body, 18 ... Cylindrical body, 19 ... Fixed rod, 20, 27 ... Spring, 21 ... Movable rod,
23...Base, 24...Fork part, 26...Protrusion part,
28... Protrusion.

Claims (1)

[Claims] 1. Brackets are fixedly installed on the left and right sides of the rear part of the cargo box, and the rear rotating shaft is rotatably provided by the brackets, and an engaging means for locking the rear rotating shaft is provided on the vehicle body frame. In a three-turn dump truck in which the cargo box rotates up and down around a rear rotation axis during rear dumping, the rear sliding door is pivoted at the left and right ends of the upper part of the cargo box so that it can freely rotate upward. A member to be secured, such as a pin, is fixed to the lower end portions of both sides of the rear sliding door, and a locking hook is provided at the rear of the cargo box so as to be rotatable in correspondence with the member to be secured, A cam plate is fixed to the rear rotation shaft, a bell crank that abuts the cam plate is pivotally supported by the cargo box, the bell crank and the locking hook are connected by a locking mechanism, and the bell crank is connected to the cargo box by a locking mechanism. An automatic rear door opening/closing device for a three-turn dump truck, characterized in that a spring is interposed between the locking hook and the locking mechanism in a direction to release the locking hook.