JP2678800B2 - Dump truck rear door opening and closing device - Google Patents

Description

The present invention relates to a rear door opening / closing device for a dump truck, and more particularly to a rear door opening / closing device for a dump truck, which has a rear door that opens / closes when the loading platform moves up and down, and is used for soil, rot, etc. The present invention relates to a rear door opening / closing device of a tamper car that carries a load.

"Prior Art" Conventionally, some rear door opening / closing devices for dump trucks have been proposed. For example, Jikkou Sho 62
The invention disclosed in Japanese Patent No. 1783 uses a hydraulic cylinder for opening and closing the rear door and opens the rear door in a horizontal state with the floor surface of the luggage carrier. In addition, Japanese Patent Application No. 1-2054 filed by the applicant earlier
The invention of No. 83 is a folding link connected to the lower end of the rear door through a turnbuckle, and a receiver pivotally attached to a frame below the loading platform so that the free end of the folding link can be supported. It is composed of metal fittings, and has a configuration in which the rear door is opened in a horizontal state with the floor surface of the loading platform as in the above-described embodiment.

However, in all of these examples, since the rear door is opened to the rear of the loading platform, when the load is unloaded, the load slides on the inner wall surface of the rear door and falls, and the rear door is scratched and the load on the rear door and each member is reduced. Weight is added directly or indirectly, there is a problem in terms of durability, and when closing the rear door, it will push up the rear door and it will require considerable force, so the hydraulic cylinder must be enlarged, etc. There was a drawback.

"Problems to be Solved by the Present Invention" In view of the above-described drawbacks of the conventional techniques, the present invention does not damage the inner wall surface of the rear door when unloading a load, and each member that constitutes the rear door and the opening / closing device. Therefore, there is provided a Dunnucar rear door opening / closing device in which the weight of the cargo is not added, the probability of failure is low, and the rear door can be opened and closed automatically and smoothly by an inexpensive member.

[Means for Solving Problems] The rear door opening / closing device for a dump truck according to the present invention has two left and right rear doors 3a and 3b, and inner wall surfaces of these rear doors are outer wall surfaces of both side walls 7 and 8 of the luggage carrier 1. And a pair of left and right driven links 11, one end of which is pivotally supported at the rear end of the bottom surface of the floor of the loading platform 1 and the other end of which is pivotally supported at the lower surface of the inner end of the rear door so that they rotate horizontally until they face each other. A portion close to the portion is located near the rear end of the bottom surface of the floor of the loading platform 1, while the other end is pivotally supported by a pair of left and right drive links 14 pivotally supported on the underside of the outer end of the rear door, and rotatable about the loading platform. The horizontal axis
And a slide turning piece (20) having an arcuate slide portion (20d) that is fixedly provided on the load carrier (18) and comes into contact with the fixed rod (22) on the side of the carriage (21) when the load carrier is in the horizontal state, and the load door is in the horizontal state. When 3a and 3b are closed, the drive link 14 is
A first spring member having the other end attached to the drive link 14.
While the rear door is pulled in the direction in which the rear door is always open at 17, the connecting rod 28 interposed between the horizontal shaft 18 and the drive link 14
The other end of the slide turning piece 20 locked by the lock bar and prevented from rotating between the fixed rod 22 and the loading platform 1 has the other end.
A second spring member 24 attached to the rear side door is pulled in a direction to open the rear door in the same manner as the pulling direction of the first spring member, and the upper outer ends of the left and right rear doors 3a and 3b are engaged. It is characterized in that it is engaged with both side walls 7, 8 by an engaging means having a dowel pin 6.

[Examples of the present invention] Examples of the present invention will be described in detail below with reference to the drawings.

In one embodiment shown in FIGS. 1 to 8, first,
1 is a bed of a large or small dump truck 2. Reference numeral 3 is a rear door that covers the rear opening of the luggage carrier, and the rear door 3 is divided into left and right parts as shown in FIG. A turning stopper piece 4 and a receiving piece 5 for receiving the turning stopper piece 4 are provided on the outer wall surfaces of the inner ends of the left and right rear doors 3a, 3b which face each other. 6 are engaging pins provided on the upper surfaces of the outer end portions of the left and right rear doors 3a and 3b, respectively, and these engaging pins 6 project to the upper surfaces of the rear end portions of the left and right side walls 7 and 8 of the luggage carrier 1 and fixedly. The left and right locking plates 9 are engaged with each other.

Next, 10 is a rear door opening / closing device. Since the rear door opening / closing device 10 has the same structure on the left and right as shown in FIG. 6 or 8, the same reference numerals are given to the same parts on the left and right for convenience.
Only one will be described.

That is, 11 is a driven link, one end of which is at the rear end of the floor underside of the loading platform 1 and the other end of which is pivotally supported at the lower surface near the inner ends of the rear doors 3a, (3b) via pivot pins 12 and 13, respectively. so,
The driven link 11 is formed in an L shape in this embodiment.

The part of 14 near the one end is located near the rear end of the bottom surface of the floor of the loading platform 1, while the other end is pivotally supported on the underside of the outer end of the rear door 3a (3b) through pivot pins 15 and 16, respectively. The drive link 14 is formed into an S-shape as a whole. 17 is a first spring member having one end attached to the bottom surface of the floor of the loading platform 1 and the other end attached to the drive link 14, respectively. The first spring member 17 always pulls the rear door 3a (3b) in the opening direction. It should be noted that one end of the first spring member 17 should be attached to the outside of the pivot pin 15 and to the front side of the loading platform 1, and the other end has a drive link formed by the spring force of the spring member 17. Because of the rotation as shown in FIG. 8, it is desirable to attach the drive link 14 to a portion near the pivot pin 15 of the drive link 14.

Reference numeral 18 denotes a horizontal shaft that is rotatably provided laterally on a front part of the floor underside of the loading platform 1 or a portion near the front part via a pair of opposing pivot plates 19, and the horizontal axis 18 extends in the longitudinal direction of the loading platform 1. In contrast, they are provided in a crossed state.

Reference numeral 20 denotes a slide turning piece fixedly provided at the center of the horizontal shaft 19 for closing the rear door. In this embodiment, the slide turning piece 20 is fixed to the horizontal shaft 19 as shown in FIG. Ring-shaped mounting portion 20a, a small protruding portion 20b formed at an appropriate portion of the mounting portion 20a, and an outer periphery of the mounting portion 20a opposite to the position where the small protruding portion 20b is provided or apart from the mounting portion 20a. From the connecting portion 20c, and a fixed rod 22 that is formed inward from the connecting portion 20c in an arc shape around the horizontal shaft 18 and that is provided laterally on the truck or frame 21 of the dump truck 2.
The small projection portion 20b, which comprises a slide portion 20d that is in sliding contact with the small projection portion 20b.
A mounting pin 23 is provided in parallel with the horizontal axis 18.

24 has one end on the mounting pin 23 and the other end on the loading platform 1
A plurality of second spring members attached to spring attachment pieces 25 fixed to the bottom surface of the floor. The second spring member 24 is such that at least the loading platform 1 is parallel to the carriage 21 as shown in FIG. At some point, the slide turning piece 20 is always pulled in one direction (in the case of FIG. 5, the hour hand direction).

26 is a rotating plate fixedly provided on the protruding portion of the horizontal shaft 18,
One end of a connecting rod 28 is attached to the rotating plate 26 via a U-shaped first joint member 27.

Reference numeral 29 is an intermediate piece provided at one end of the drive link 14 via a pivot pin, and the intermediate piece 29 has a U-shaped second joint so as to intersect with the first joint member 37. A member 30 is provided. The other end of the connecting rod 28 is attached to the drive link 14 via the second joint member 30 and the intermediate piece 29, respectively.

It should be noted that the connecting rod 28 can be slightly rotated in the horizontal direction when it is moved forward and backward by the first joint member 30 and the intermediate piece to and from the back and forth of the luggage carrier. In addition, the fixed rod 22 on the dolly 21 side is the horizontal axis 18
Similarly, is provided in a state of intersecting with the longitudinal direction of the loading platform 1 and is positioned slightly behind the horizontal axis 18 as shown in FIG.

[Operation] First, as shown in FIG. 4, when the loading platform 1 is in parallel with the trolley 21, that is, when the loading platform 1 is in the horizontal state, the slide portion 20d of the slide turning piece 20 is trolleyed. Abutting the fixed rod 22 on the side, the horizontal shaft 18 rotates in the hour hand direction, and as a result,
The left and right connecting rods 28 are locked so as not to move backward toward the rear side of the loading platform. At this time, the drive link 14 is constantly pulled by the spring force of the first spring member 17 in the direction to open the rear door 3, and the slide turning piece 20 is pulled by the second spring member 24. It is in the closed state as shown in FIG.

Next, as shown in FIG. 7, for example, when the loading platform 1 is raised and tilted, the slide turning piece 20 is completely separated from the loading platform side fixed rod 22, and the left and right rear doors 3a and 3b are moved by the spring force of the spring member. Automatically rotates via drive and driven links,
They are located parallel to the outside of the left and right side walls 7 and 8 of the loading platform 1, respectively.

Then, when the loading platform 1 starts to rise, the horizontal axis 18 moves to the fixed rod 22.
Gradually, and at the same time, the spring force of the first spring member 17 acts on the drive link 14, which causes the drive link 14 to pivot.
, And the driven link 11 starts to rotate in the direction of opening the rear door 3 with the pivot pin as the fulcrum. On the other hand, the spring force of the second spring member 24 acts on the slide rotation piece 20,
The horizontal shaft 18 is rotated in cooperation with the spring force of the first spring member 17, and the connecting rod 28 is moved to the rear side of the luggage carrier 1. In this way, the left and right rear doors 3a, 3b respectively rotate horizontally until their inner wall surfaces face the outer surfaces of the left and right side walls 7, 8 of the luggage carrier.

When the loading platform 1 descends, the slide portion 20d of the slide rotation piece 20 comes into sliding contact with the fixed rod 22 of the carriage 21 side from the tip end side thereof, and the slide rotation piece 20 resists the spring force of the second spring member. This time, it rotates in the opposite direction (counterclockwise direction when referring to Fig. 4), and as a result, the horizontal axis 18 also rotates in the same direction,
The connecting rod 28 moves to the front side of the loading platform 1, and the driven link 14
Rotates in the opposite direction against the spring force of the first spring member 17. Then, the left and right rear doors 3a and 3b are closed as shown in FIG.

"Effects of the present invention" As is clear from the above description, the present invention has the following effects.

(1) Since the rear door is divided into two parts, and the left and right divided rear doors are respectively moved to the outside of both side walls of the luggage carrier,
The load on the rear door is not burdened when the load is unloaded, and at the same time, the load does not slide on the rear door and fall.

Therefore, it is possible to eliminate the failure of each member of the switchgear due to the weight of the load and the damage to the rear door due to the load. Since no hydraulic cylinder is used, the probability of failure is low.

(2) The left and right rear doors are automatically rotated and opened to the outside of both side walls of the loading platform by using the lifting and lowering movement of the loading platform,
Or it can be closed back.

(3) When the slide rotation piece separates from the horizontal axis, the lock of the connecting rod is released, and the left and right rear doors can be completely opened via the plurality of links only by the spring force of the first spring member.

(4) In the case of the embodiment in which the slide member turning piece is always pulled in one direction by the second spring member, the connecting rod moves rearwardly of the loading platform via the sliding turning piece and the horizontal shaft when the loading platform rises. As a result, the drive and driven links rotate smoothly in the opening direction of the rear door in cooperation with the movement.

[Brief description of the drawings]

1 to 8 are explanatory views showing an embodiment of the present invention. Specifically, FIG. 1 is a front view showing a use state, FIG. 2 is a right side view showing a main part, FIG. 3 is a perspective view showing the main part, and FIG. 4 is an explanatory view from the front showing the main part. FIG. 5 is an explanatory view of the slide turning piece, FIG. 6 is an explanatory view of the loading platform as seen from the bottom surface, and FIGS. 7 and 8 are explanatory views showing the opened state of the rear door. 1 ... Luggage platform, 3 ... Rear door, 4 ... Rotation stopper piece, 10 ... Rear door opening / closing device, 11 ... Follower link, 14 ... Drive link, 17 ... First spring member, 18 ... Side Shaft, 20 …… Slide turning piece, 21 …… Bogie, 22 …… Fixing rod, 24 …… Second spring member, 28 …… Coupling rod.

Claims (1)

(57) [Claims] 1. Left and right rear doors 3a, 3b divided into two parts, and one end portion thereof is horizontally rotated until the inner wall surfaces of these rear doors face the outer wall surfaces of both side walls 7, 8 of the luggage carrier 1, respectively. 1 is a pair of left and right driven links, one of which is at the rear end of the floor underside and the other end is pivotally supported at the underside of the inner end of the rear door.
And a pair of left and right drive links 14, one end of which is located near the rear end of the bottom surface of the floor of the loading platform 1 and the other end of which is pivotally supported by the underside of the outer end of the rear door, and the loading platform. It is fixedly provided on a horizontal shaft 18 horizontally rotatably mounted, and
And a slide rotation piece 20 having an arcuate slide portion 20d that comes into contact with the fixed rod 22 on the side of the carriage 21 when the cargo bed is in a horizontal state, and the drive link is provided when the rear doors 3a, 3b are closed when the cargo bed is in a horizontal state. Reference numeral 14 denotes a first spring member 17 having the other end attached to the drive link 14 and is pulled in a direction in which the rear door is always opened, while a connecting rod 28 interposed between the horizontal shaft 18 and the drive link 14 is provided. The slide rotation piece 20 locked by the lock bar 22 and prevented from rotating between the fixed rod 22 and the loading platform 1 has a second spring member 24 attached to the loading platform 1 at the other end thereof. Similar to the pulling direction of the members, they are pulled in the direction to open the rear doors, and the upper outer end portions of the left and right rear doors 3a, 3b are engaged with both side walls 7, 8 by engaging means having engaging pins 6. Rear door opening and closing device for dump trucks characterized by matching