JPS5937252B2 - Dump truck loading platform rear door lifting device - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a dump truck platform in which the rear door of the dump truck platform automatically opens high when releasing the loaded object, allowing large rocks etc. to be discharged as they are. This concerns the rear door.

As is well known, dump trucks are mainly used to transport earth and sand generated at construction sites, industrial waste, and soil for construction purposes. When handling a dump truck, something that cannot be pulled out between the rear door and the bottom of the truck bed will get caught in the rear door when lifting the loading platform to discharge dirt, which will not only interfere with the dumping operation but also interfere with normal dump operation. Since it is not possible to unload these large stones from the loading platform, the loading platform must be returned to its original position, the rear door opened, and the dumping operation performed again, which is not only complicated, but can also be dangerous. It is very inconvenient.

However, the external dimensions of vehicles are regulated by law, and for this reason, in order to be able to dump large stones and other debris from the loading platform along with dirt in a single dump operation, it is necessary to remove the upper support part of the rear door. The purpose cannot be achieved unless the height of the rear door is increased, and this would result in an illegal structure with a raised rear door, which of course would not be practical even if it was usable.

In view of the current situation, the present invention has been developed to keep the external dimensions of the loading platform within the legal regulations, that is, to keep the outer dimensions of the loading platform within the specified height of the loading platform under normal conditions, and to automatically move the rear door to a high place during dump operation. The purpose of this invention is to provide a rear door mechanism for a dump truck cargo box that has a flip-up function that allows large objects to be released from the loading platform without any hindrance. .

In the present invention, a fixed pillar with a door lifting link and a part of its operation mechanism installed inside is arranged at the rear of the door body on both sides of the loading platform of a dump truck, and a rear door is attached to the tip of the door lifting link.
Arm rods or mounting pieces are provided on both sides of the front of the cargo platform, where it pivots relative to the chassis, respectively, projecting sideways, and the ends of the arm rods or mounting sections are provided with guides provided within the fixed pillar at the single door lifter and the base end of the link. The flexible strips were connected under tension via or directly.

In addition, in the present invention, the door lifting link attached to the fixed column is formed in an inverted shape, and the lower end of the vertical part of the link is connected to the left and right sides by a horizontal member, and the lower end of the rear door is connected to this horizontal member. In addition to being hinged, the opening/closing locking fittings for the rear door are installed at the upper end of the vertical part, and during dump operation, the rear door becomes almost parallel to the floor of the slanted loading platform and lifts upward according to the operation of the door lifting link. It was made so that the door could be opened by being lifted up.

With this configuration, according to the present invention, even if the load in the loading platform is earth and sand mixed with large rocks, etc., as the loading cylinder is lifted and tilted by the dump cylinder, the relationship between the loading platform and the vehicle body is improved. The base end of the door lift link is pulled downward according to the inclination of the loading platform by a flexible strip stretched between the arm rod provided in the gravity position of the pivot pin and the base end of the door lift link installed in the fixed column. As a result, the tip of the link is lifted, and the rear door of the loading platform is lifted upward, so that the distance between the loading platform floor and the lifted position of the rear door is equal to the length of the lifting side of the door lifting link. It is larger than the height of the door, allowing large stones, etc. to be ejected without difficulty, and when the loading platform is returned to its normal position, it will fall within the specified height dimension and can be transported in its normal state.Therefore, some structure of the loading platform has been changed. The rear door can be lifted upwards in conjunction with the dumping operation of the loading platform, making it easier to achieve the intended purpose even when handling large objects with dimensions within the specified specifications and without requiring any additional power. It can be said to be an excellent invention because it has a simple structure, does not break down, and can be provided at a low cost.

The present invention will be explained in detail below with reference to embodiment figures.
In FIGS. 1 to 4, 1 is a chassis, 12 is a loading platform,
3 is a pivot bracket for the chassis 1 of the loading platform 2; 4 is a pivot pin; 5 is a cylinder for raising and lowering the loading platform; 6 is a side door; 7 is a closed box-shaped fixing column; It has an appropriate length according to the thickness of the door and is fixedly erected on both the left and right sides up to the rear end, and a flip-up mechanism 10 for the rear door 8 is incorporated therein.

The rear door lifting mechanism 10 includes a lever link 11 for lifting the door, which is formed in an inverted shape so as to extend from the upper surface of the fixed column 7 to the rear surface thereof, with the main body supported by a pin 12 at an appropriate position above the fixed column 7. The lower end of the vertical portion 11' of this lever link 11 is integrally connected to that of the opposite lever link by a horizontal member 13, and this horizontal member 13 is located at the lower rear end of the loading platform 2. The lower end outer surface of the rear door 8 is connected to this horizontal member 13 by a hinge 14, and the vertical part 11 of the lever link 11
A locking piece 15 of the rear door 8 is fixed to the upper end, and a stopper 8' can be freely engaged and detached from the locking piece 15 on the rear door side.

A rope attachment 16 is attached to the base end 11'' of the lever link 11, and arm rods 17 are laterally protruded from the rope attachment 16 in a symmetrical manner to the front force position of the loading platform pivot pin 4 of the chassis 1. A steel cable 2 is attached to the rope attachment 18 attached to the tip.
0 was stretched under tension around a guide roller 19 fixed in the middle part of the fixed column 7, passing through a through hole 21 at the lower part of the fixed column 7.

The operating range of the lever link 11 is determined by the lever ratio of the link,
It is determined by the dimension between the chassis 1 side protruding arm rod 1γ and the pivot pin 4 and the length of the steel cable 20 stretched between both rope attachments 16 and 18, and the loading platform 2 has the maximum inclination angle. (
Care should be taken so that the inner surface of the rear door 8, which operates integrally with the lever link 11, is approximately parallel to the floor surface of the loading platform when the vehicle is tilted up to approximately 60°.

In addition, by integrally attaching strips of the required width to the upper and rear end surfaces of the lever link 11 so as to cover each side of the fixed column 7, it is possible to cover the open end of the fixed column 7 during normal operation, improve the appearance, and at the same time protect against foreign objects. It is possible to prevent internal intrusion and increase the strength of the lever link.

To explain the operation of the present invention constructed as above, in normal conditions, the loading platform 2 is normally supported on the chassis 1 as shown in FIG. The rear door flip-up mechanism 10 is also held in place as shown, and the rear door 8 and its attachment are mounted so that the transverse member 13 stands upright on the rear end of the loading platform 2 and the lower end of the door 8 and the loading platform are connected in a well-known manner. In addition, the side door 6 and the end of the fixed column 7 are connected and fixed by a well-known structure, so that cargo can be loaded and transported in the same manner as in the conventional case.

When transporting earth and sand mixed with rocks and the like and discharging it from the loading platform, as the loading platform 2 is tilted by the dump operation cylinder 5, the rear door flip-up mechanism 10 provided at the rear of the loading platform 2 lifts up the loading platform. A steel cable 20 end for operating the lever link 11 is connected to the mount 18 through the arm rod 17 in front of the pivot pin 4 position.
As the front part of the loading platform 2 is lifted, a downward pulling force is generated on the steel cable 20, and this steel cable 20
Since the base end 11'' of the lever link 11 connected to the upper end is pulled downward, the inverted-shaped rear part rotates upward using the pivot pin 4 as a fulcrum within the fixed column 7, and the rear part of the lever link 11 is vertically rotated. The rear door 8 attached to the piece 11' can be lifted up while being fixed to the lever link vertical piece 11' and the horizontal member 13, and when the loading platform 2 is tilted to its maximum, the rear door 8 is attached to the loading platform floor and the rear door as shown in FIG. 8 and the inner surface are parallel to each other when the door opens.

In this state, even stones with a size up to the distance T between the rear door 8 and the floor can easily slide out from the loading platform and be released.If the releasing operation is completed and the cylinder 5 is returned, the loading platform can be released. 2 returns to the horizontal position from the tilted state, the steel cable 20 stretched between the base end 11'' of the lever link 11 and the chassis 1 side arm rod 17 operates in reverse while maintaining tension, so that the rear door 8 and the rear part of the lever link 11 rotate downward to automatically open the door.

In short, the steel cable is movable by keeping a fixed length of the steel cable in tension due to the deviation difference between the loading platform pivot point and the chassis mounting position of the steel cable 20, and rotating the movable end of the steel cable around the pivot point. By displacing the end and activating the lever link connected to it, the rear door can be opened and closed in conjunction with the dumping operation of the cargo platform without using any additional power.

In the above embodiments, the rear door is raised integrally with the inverted lever link, but in addition, as shown in FIGS. 5 and 6, A straight lever link 11A is provided in the same way as in the previous embodiment, pivoting 12 at the main body, and a steel cable 20 is connected from the base end 11' of this link to the end of the arm lever 17 on the chassis 1 side as in the previous embodiment. is tensioned and a locking piece 15 is fixed to the upper end of the lever link 11A, whereas the rear door 8A is secured by a known means with a stopper 8' detachably attached to the lever link 11.
In addition to being connected to the A end, the latch part at the bottom of the door 8A also adopts a known structure in which the latch is automatically unlatched during dump operation.

Of course, the fixed column 7 is open only at the upper surface where the lever link 11A is attached, and a cover plate having a width equivalent to the thickness of the fixed column 7 is integrally fixed to the upper surface of the lever link to cover the opening. A through hole 21 for passing the steel cable 20 to the rope attachment 18 at the end of the arm rod 17 is opened on the lower surface.

With this structure, under normal conditions, the rear door 8A is in the normal state in which the lower end latching piece 8' is engaged with the latching portion 22 to close the loading platform 2, as shown in FIG. When the loading platform 2 begins to incline during dump operation after loading and transporting earth and sand, the position of the pivot pin 4 of the loading platform 2 relative to the chassis 1 and the attachment of the steel cable 20 gradually become lever links due to the deviation difference between the positions. The base end of the lever link 11A is pulled down, and the rear door 8A is lifted together with the tip of the lever link IIA. When the loading platform 2 is tilted to its maximum inclination, the tip of the lever link 11A stands up upwards as shown in FIG. The locking piece 15 and the locking punch 8
In the engaged state with ', the rear door 8A assumes a suspended posture.

Therefore, if large stones etc. are mixed with the earth and sand, door 8A
If the distance from the support position to the floor is within the dimension, even if it hits the door, it will push the door open and fall, achieving the intended purpose.

In this case, when the rear door is initially tilted, the lower end locking portion is disengaged and opened in the same manner as the well-known door.

When the dumping operation is completed and the loading platform 2 is returned to the horizontal position, the lever link 11A also operates in reverse, and the rear door 8A returns to its original position and closes.

Therefore, when using the loading platform in a state other than dumping, both the side doors 6 and the rear door 8 or 8A can be opened by removing the locking rods with the fixing pillar 7 from the locking parts. It is now possible to carry out the work of loading and unloading goods on the vehicle, and it has become possible to perform the above functions within the specified vehicle regulation dimensions and in a legal state. 1) They are not equally complicated and therefore do not cause failures.

In addition, in the above-mentioned dual-sword type, the lever link operating steel cable 20 for lifting the door is provided with appropriately wide guide sheeps (not shown) below the through hole 21 of the fixed column 7 and at a position close to and parallel to this. , By connecting these guide sheeps to a single piece, such as a hanging ring which protrudes sideways on the chassis 1 instead of the arm rod at the lower end, the purpose can be achieved without the need for the arm rod to protrude. This is possible.

Furthermore, as a separate method, a door lifting link 1'L3 as shown in FIG. 7 can be adopted, and the same reference numerals are used in the figure to indicate the same mechanism parts as in the above-mentioned embodiment.

The door lifting link IIB has its base end pivoted on the pin 12, a chain wheel 25 of an appropriate diameter is fixed to this base end, the upper end of the chain wheel 26 is wrapped around the chain wheel 25, and its tip is The chain wheel 25 is fixed in place on the link side, and the lower end of the chain wheel 26 is fixed to the tip of the arm rod 17 provided on the chassis 1 side through the through hole 21 on the lower surface of the fixed column 7 by known means.

In this way, when the loading platform 2 is operated for dumping, as the loading platform tilts as described above, the upper part of the loading mechanism will be prevented as the loading platform 26 extends due to the deviation difference between the pivot point and the fixed end of the chenno 26. A rotational force about the pin 12 is applied to the chain wheel 25, and as a result, the link 11B integrated therewith rotates via the chain wheel 25, and the rear door 8 attached to the tip thereof is lifted by the upper blade. become.

When the loading platform 2 is returned to its original position, the reverse effect as described above is performed, and when the loading platform returns to the horizontal position, the rear door is also closed, producing the same effect as in the previous embodiment.

Note that a steel cable and sheave may be used instead of the chain wheel and chain wheel described above.

Furthermore, it is also possible to optionally use a ring chain in place of the above-mentioned steel cable, or use a chain wheel in place of the guide rollers to tension the roller chain.

It goes without saying that the flip-up dimension T of the rear door can be changed to a desired size by changing the length of the lever link.

[Brief explanation of the drawing]

The drawings show the main parts of an embodiment of a dump truck equipped with the device of the present invention, in which FIG. 1 is a partially cutaway front view, FIG. 2 is a view showing the mode during dump operation, and FIG. 3 4 is an enlarged detailed view of the main parts, FIG. 4 is a schematic perspective view, FIG. 5 is a partially cutaway front view of the case law device, FIG. 6 is a diagram showing the operating mode, and FIG. 7 is yet another embodiment of the device. FIG. 8 is a diagram showing the operation mode. 1... Chassis - 12... Loading platform, 3...
... Pivot bracket, 4... Pivot pin, 5
...Cylinder for raising and lowering the loading platform, 7...Fixing column, 8,8A...Rear door, 10...Jumping mechanism, 11,11A... ... Lever link for lifting the door, 11' - ... Vertical part, 11'' ... Base end, 11B ... Door lifting link, 12 ...
...Pivot pin, 13...Horizontal member, 14...
... Hinge, 16, 18 ... Rope attachment, 1
7...Arm rod, 19...Guide roller,
20...Steel cable, 25...Chain wheel, 26.
...Cheno.

Claims (1)

[Scope of Claims] 1 Box-shaped fixed pillars each having an inverted-shaped door lifting link and a part of its operating mechanism are connected and erected at the rear of the door bodies on both sides of the dump truck's loading bed. and connect the vertical lower end of the tip of the door lifting link to the left and right sides with a horizontal member,
The rear door is hinged to this horizontal member at its lower end, and the opening/closing locking fittings of the rear door are attached at the upper end position of the vertical part of the link, respectively, and the opening/closing locking fittings of the rear door are attached at the upper end position of the vertical part of the link. For arm rods or attachments, each piece is protruded horizontally,
A loading platform of a dump truck characterized in that the end of the arm rod or attachment piece is connected to the proximal end of the door lifting link by a flexible rod under tension via a guide provided in a fixed column or directly. Rear door lift device. 2. The door lifting link has its base end pivoted on a pin, a chain wheel or sheave of an appropriate diameter is fixed to this base end, and the upper end of the flexible strip is wrapped around this chain wheel or sheave, and its tip is 2. A dump truck loading platform rear door flip-up device according to claim 1, wherein the lower end is connected directly or through a guide to a chassis mounting portion. 3. The device for flipping up the rear door of a dump truck loading platform as set forth in claim 1, wherein the lower end of the flexible strip is connected to the chassis side fixation piece via a guide sheave provided on the lower side of the loading platform. 4. The dump truck bed rear door lifting device according to claim 1, wherein a plate material covering the opening of the fixing column is fixed to the upper surface and rear surface of the door lifting link, or only to the upper surface. 5. The dump truck bed rear door lifting device according to claim 1, wherein the flexible strip connecting the base end of the door lifting link and the arm rod is a steel cable. 6. The dump truck bed rear door lifting device according to claim 1, wherein the flexible strip connecting the base end of the door lifting link and the arm rod is a ring chain. 7. Claim 1, in which a roller chain is used as the flexible strip, a chain wheel is used as a guide provided in the fixed column, and the proximal end of the door lifting link and the arm rod are tension-connected via the chain wheel. Lifting device for the rear door of the dump truck mentioned above.