JP2767195B2 - Dump truck rear door opening and closing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear door opening / closing apparatus for a dump truck, and more particularly to a rear door opening / closing apparatus for a large dump truck having a rear door which automatically opens and closes in response to a lifting and lowering movement of a loading platform.

[0002]

2. Description of the Related Art Heretofore, in general, a rear door of a rear door opening / closing device has been widely used in which a rear door is opened / closed by using a driving force of a driving cylinder provided at a lower portion of a cargo bed.

For example, Japanese Patent Application Laid-Open No. 58-20533 discloses
The drive cylinder in the space below the floor of the carrier and the truck
And the front end of the operating rod of this drive cylinder and the rear
Close the rear door with the bracket at the bottom of the door.
Rotating (driving) link and pushing up (follow) during chain
Each pivot of the link is connected in a straight line.
Thus, the rear door opening and closing device described in this publication has a drive system.
When the operating rod of the cylinder is extended , the drive link moves below the floorboard.
Rotate around the base axis of the support frame that protrudes from
As a result, the rear door opens. On the other hand, the drive cylinder
When the operating rod contracts, the rotary (drive) link and push up
Each pivot of the (follow) link is linear, so that
The rear door closes.

However , in the above configuration, the rear door
The pivot link and the push-up link are
Acts on the rear door because it is located linearly with other pivots
The load pressure (or opening force) of the load
Does not work, mounting drive cylinder, drive cylinder
No excessive force is applied to the parts
It is not necessary for the operating rod to directly function as a stopper
And the operating rod of the drive cylinder is displaced or
Eliminates the problem that the mounting part of the cylinder is deformed
be able to.

[0005]

However, the above structure
The drive cylinder, rotating (drive) link, push
Each member such as a lift (follow-up) link is connected to the vehicle floor and the bogie.
Must be properly combined in the limited space of
Eventually, these parts are exposed outside the carrier.
It will be installed due to external factors (such as
May hit the tires during dumping, etc.)
In consideration of the above, protective frames or protective covers must be provided as appropriate.
I had to. The present invention is based on the above-described conventional embodiment.
While taking advantage of its advantages and considering the above problems,
Rear door of a dump truck that does not need to consider partial factors
It is to provide a switchgear.

[0006]

The rear door opening / closing device for a dump truck according to the present invention has a lower end pivotally supported by the loading platform 1 via a first fixed shaft 5 so that the lower end can be opened outward from the upper end. Rear door 4 and the part near the rear end of the floorboard of the loading platform 1
Vertical direction upper end portion through the second fixed shaft 17 is pivotally supported position
A drive link 16 of the direction, the the lower end of the drive link 1
One end is pivotally supported via a movable shaft 19, while the other end is a driven link 18 pivotally supported by a projecting bearing portion 20 at the lower end of the rear door, and a drive link above and below the driven link 18. 16 and the space under the floor plate between the rear door 4
Disposed of along with the driven links 18 so as not to be exposed to the section
A driving cylinder 21 which is extended and contracted by the driving force of the driving cylinder, and has an operating rod 22 whose tip is pivotally supported at the center of the driving link. When the operating rod contracts, the rear door is closed. It is characterized in that it rotates in the closing direction, while the rear door rotates in the opening direction when the operating rod is extended.

[0007]

When the operating rod of the driving cylinder contracts, the rear door rotates in the closing direction via the driving link and the driven link, while when the operating rod is extended, the rear door opens via the driving link and the driven link. Rotate in the direction.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

In one embodiment shown in FIGS. 1 to 6,
Reference numeral 1 denotes a bed of the large dump truck 2. On the other hand, reference numeral 3 denotes a bogie of the large dump truck 2 or a lower frame.

Reference numeral 4 denotes a rear door that covers the rear opening of the loading platform 1. The rear door 4 is used when the loading platform 1 rises in an inclined state.
The lower end is pivotally supported by the carrier 1 via the first fixed shaft 5 so that it can be opened outward from the upper end. First
The fixed shaft 5 is appropriately laid horizontally below the rear end of the carrier 1 via a bearing.

Reference numeral 6 denotes a lock member for closing the rear door, which is provided at the upper end of the loading platform 1 and the rear door 4. In this embodiment, a pair of left and right engaging pieces 9 pivotally supported via pins at the rear ends of the left and right side walls 7 and 8 of the loading platform 1, and a rear door so as to engage with these engaging pieces 9 respectively. 4 left and right side walls 10, 1
1 and an engaging pin 12 protruding from the first engaging pin.

Reference numeral 15 denotes a rear door opening / closing device provided on the carrier 1 and the truck 3. Since the rear door opening and closing device 15 has the same configuration on the left and right as shown in FIG.

First, reference numeral 16 denotes a drive link whose upper end is pivotally supported via a second fixed shaft 17 at a position from the rear end of the floor plate of the loading platform 1. This drive link 16 is shown in FIG.
Notch of reinforcing frame provided integrally on the lower surface of floorboard
And the lower end thereof is rotatable in the front-rear direction of the vehicle (dump truck).

Next, reference numeral 18 denotes a first lower end of the drive link 16.
One end is pivotally supported via a movable shaft 19, while the other end is a driven link pivotally supported by a projecting bearing portion 20 at the lower end of the rear door 4. The driven link 18 is located obliquely.

A driving cylinder 21 is disposed above the driven link 18 and between the driving link 16 and the rear door 4. The drive cylinder 21 is positioned obliquely so as to be provided with the driven link 18. The rear end is pivotally supported by the carrier 1.

Reference numeral 22 denotes an operating rod which expands and contracts by the driving force of the driving cylinder 21 and has a distal end pivotally supported at the center of the drive link 16 or at a position from the center.
In this embodiment, the distal end of the operating rod 22 is pivotally supported by the drive link 16 via the joint member 23.

The rear door 4 rotates in the closing direction when the operating rod 22 contracts, and rotates in the opening direction when the operating rod 22 extends.

Although not particularly shown, the driving cylinder 2
The hydraulic unit 1 is also provided on the carrier 1 as appropriate, and the power source of the driving means is a battery mounted on the vehicle.

In the above configuration, when the operating rod 22 is extended as shown in FIG. 1, the drive link 16 rotates counterclockwise, and the rear door 4 opens via the driven link 18.

On the other hand, when the operating rod 22 contracts as shown in FIG. 5, the drive link 16 rotates clockwise and the rear door 4 closes via the driven link 18.

[0021]

As is apparent from the above description, the present invention has the following effects. (1) When the operating rod contracts, the rear door rotates in the closing direction, while when the operating rod extends, the rear door rotates in the opening direction. Therefore, the conventional embodiment (Japanese Patent Laid-Open No. 58-20 / 1983)
No. 533), the load strikingly hit the rear door.
Even if the load pressure (or the rear door opening force) is directly
Since it does not act on the drive cylinder,
No excessive force is applied to the mounting part of the cylinder . (2) External factors (stone hits during driving, dumping
May come into contact with the tires, etc.)
A A protective frame or protective cover must be
No need. (3) Easy to manufacture or combine

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram viewed from one side (a rear door is open) of a dump truck according to the present invention.

FIG. 2 is a schematic explanatory view of the dump truck according to the present invention as viewed from the back (rear).

FIG. 3 is a schematic explanatory view of a dump truck according to the present invention as seen from a plane.

FIG. 4 is an explanatory diagram of a main part of the first embodiment.

FIG. 5 is a schematic explanatory view of a state where the carrier of the present invention is inclined.

FIG. 6 is a schematic explanatory diagram viewed from one side (the rear door is in a closed state) of the dump truck of the present invention.

[Explanation of symbols]

1 ... loading bed, 3 ... trolley (lower frame), 4 ... rear door,
5: first fixed shaft, 6: locking member, 15: rear door opening / closing device, 16: drive link, 17: second fixed shaft, 18
... follower link, 19 ... first movable shaft, 20 ... bearing part, 2
1. Operating rod.

Claims (1)

(57) [Claims] 1. A rear door 4 having a lower end pivotally supported by a carrier 1 via a first fixed shaft 5 so as to be able to open outward from an upper end side, and a rear end of a floor plate of the carrier 1 near the rear end. And a vertical drive link 16 whose upper end is pivotally supported via a second fixed shaft 17 at one end, and one end of which is pivotally connected via a first movable shaft 19 to the lower end of this drive link. On the other hand, the other end is a driven link 18 pivotally supported by a projecting bearing portion 20 at the lower end of the rear door, and the floor plate is located above the driven link and between the drive link 16 and the rear door 4. In the space below
A drive cylinder 21 arranged side by side with the driven link 18 so as not to be exposed. The drive cylinder 21 expands and contracts by the driving force of the driving cylinder, and a distal end portion is pivotally supported at the center of the driving link. A rear door opening / closing device for a dump truck, wherein the rear door rotates in a closing direction when the operating rod contracts, and the rear door rotates in an opening direction when the operating rod extends.