JPH02133252A - Load receiving bed lift device - Google Patents

Abstract

PURPOSE:To improve controllability by driving a rotary shaft by a load receiving bed lift cylinder, securing to the rotary shaft a fold compression link and rotatably supporting to its point end the other end of a connection link connected to a rotatably supporting part of a tension link and a load receiving bed, in the case of a freight vehicle. CONSTITUTION:A rotary shaft 7, driven rotating by a load receiving bed lift cylinder C1, is pivotally supported to a car body frame 1 securing to the rotary shaft 7 the point end of a fold compression link 11 rotatably supporting to its point end the other end of a connection link 19 connecting its one end to a rotatably supporting part of a tension link 16 and a load receiving bed 3, and a base part of a load receiving bed storing cylinder C2 is rotatably supported to a cylinder bracket 24 secured to the rotary shaft. When the load receiving bed 3 is grounded, both the cylinders C1, C2 communicate with an oil reservoir, and the bed 3 is placed in a horizontal direction by a return spring 30 next lowered by the own weight. In case of storage in a load case 2, the cylinder C2 is extended, and the cylinder C1 is actuated being associated with lifting the load receiving bed 3 through the bracket 24 and the rotary shaft 7. Thus, lifting can be performed by one time operation.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a loading platform for a vehicle, which is provided on a vehicle such as a freight vehicle, and is capable of loading and unloading cargo between the loading surface of the vehicle and the ground. This relates to a lifting device.

(b) Conventional technology In a conventional loading platform lifting device, when lowering the loading platform from the storage position of the cargo box to the position where it touches the ground, first press the lower button to lower the loading platform a little, and then press the open button. He pushed the loading platform to a horizontal position, and then pressed the lower button to lower the loading platform to a position where it touched the ground.

In addition, when raising a cargo receiving platform that is on the ground to the storage position of a cargo box, first press the raise button to raise it to a position slightly below the floor of the cargo box, then press the close button to raise the cargo receiving platform. After that, the lift button was pressed to move the cargo receiving platform to the storage position of the cargo box.

(C) Problems to be Solved by the Invention As a result, there are many operations and they are complicated, placing a heavy burden on workers. Therefore, an object of the present invention is to reduce the burden on the operator by making complicated operations simple.

Means for Solving the Problems In order to solve the above object, the present invention rotatably provides a rotary shaft rotatably driven by a cylinder for lifting and lowering a loading platform on a vehicle body frame, and a refractive compression link that can be bent is provided on the rotary shaft. The proximal end of a tension link is pivotally supported on the vehicle body frame, a loading platform is pivotally supported at the tip of the tension link so as to be able to rise and fall, and the tension link and loading platform are attached to the tip of the bending compression link. The other end of the connecting link whose one end is connected to the shaft support of the rotary shaft is pivotally supported, and the base of a cylinder for storing a loading platform for raising and lowering the loading platform is pivotally supported by a cylinder bracket fixed to the rotating shaft. do.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a freight vehicle V equipped with a loading platform elevating device according to the present invention.
A side view of is shown. A cargo box 2 is mounted on the body frame l of the vehicle V, and the rear opening of the cargo box 2 is opened and closed by a cargo receiving platform 3 which also serves as a tailgate. It is raised and lowered while being held approximately horizontally.

Next, the configuration of the loading platform elevating device E will be explained with reference to FIGS. 1 and 2.

A pair of left and right mounting frames 4.4 above the side opening are welded to the lower rear end of the vehicle body frame 1, and the tips of these mounting frames 4.4 are integrally connected by a connecting shaft 5.

Furthermore, right and left bearings 6, 6 are integrally provided at the base of 4, and a rotating shaft is rotatably supported in these bearings 6, 6 as shown in FIG.

As shown in FIG. 2, a swinging arm 8 is fixed to the center of the rotating shaft 7 in the left-right direction, and a loading platform lifting cylinder C1 is connected between the tip of the arm 8 and the mounting frame 4. The rotation shaft 7 can be rotated via the arm 8 by the extension operation of the cylinder C1. Compression links 9 and 9 are respectively fixed to both ends of the rotating shaft 7 in close proximity to the mounting frames 4 and 4 with connecting pins 13 to the compression link arms 9. Mr. and Mrs.

The base end of the compression link IO is rotatably connected to the compression link arm 9 by a connecting pin 13. The compression link arm 9 and the compression link 10 constitute a bent compression link 11. A stopper 12 made of a bolt is screwed onto the compression link arm 9, and this stopper 12 engages with the base of the compression link IO to prevent the compression link 10 from bending downward relative to the compression link arm 9. configured.

Further, the left and right mounting frames 4.4 and the bearing arms 14.14 fixed thereto have a tension link 1B with a pivot shaft 15.15.

The base ends of 16 are connected to each other so as to be able to swing up and down.

The compression link IO and the tension link 16 both extend in the same direction and have a length that reaches the rear end of the cargo box 2.

As shown in FIG. 1, the tip 16 of the tension link 16,
is bent upward substantially vertically, and has a bearing portion 16 at its tip.
A support shaft 17 is supported on the support shaft 17, and a bracket 18 is integrally fixed to the base end of the third cargo receiver.
It is pivoted so that it can freely rotate up and down. Further, one end of a connecting link 19 is rotatably supported on the support shaft 17, and the compression link l is attached to the free lower end of the connecting link 19.
A bearing portion 101 provided at the free end of O is rotatably connected with a connecting pin 20.

A parallel link mechanism is constituted by the rotating shaft 7, the bending compression link 11 consisting of the compression link arm 9 and the compression link 10, the pivot shaft 15, the tension link 16, the support shaft 17, the connecting pin 20, etc. The link configuration L is
By expanding and contracting the load receiving platform elevating cylinder C1, its tip part is raised and lowered, and the third load receiver supported there is moved to the lowered position shown in FIG. It is possible to move up and down between the raised position shown in position (b).

As shown in FIG. 1, the stopper 23
is fixed to the stopper 23, and the tip of the tension link 16 engages with this stopper 23, thereby regulating the upper limit position of the loading platform elevating device E.

On the outer surface of the compression link 10, there is a storage rack for rotating the loading rack 3 from a raised position, that is, a use position (FIG. 1 (B) position) to a storage position (FIG. 1 (A) position). Next, the structure of the mechanism A will be explained. A cylinder bracket 24 is fixed to the end of the rotating shaft 7 on the outside of the compression link arm 9.
The base end of the barrel portion 25 of the single-acting cylinder C for storing the loading platform is rotatably supported by a support pin. The single acting cylinder C extends along the compression link 10, and a bushing rod 27 is integrally connected to the tip of the piston rod portion 25 via a spring holder 26. The tip of this bushing rod 27 is connected to 8 with a connecting pin 29. Both ends of a return spring 30 made of a compression coil spring surrounding the outer periphery of the barrel portion 25 1 and piston rod portion 25 1 of the single acting cylinder C 1 are connected between the pivot pin 32 and the spring holder 26 . The elastic force of the return spring 30 always urges the single acting cylinder C1 in the direction of contraction. Therefore, when the single-acting cylinder C1 for storing the cargo tray is extended, the cargo tray 3 rotates around the support shaft 17 in the direction of the arrow a in FIG. By contacting the connecting link 19, the loading platform 3 can be raised and rotated from a substantially horizontal raised position, ie, a use position (b), to a substantially vertical storage position (c) (solid line position in FIG. 1).

When the single-acting cylinder C is released, the elastic force of the return spring 30 operates the single-acting cylinder C in the contraction direction and forcibly moves the third cargo receiver from the storage position (c) to the use position (b). After the rotation, the loading platform 3 is rotated to the use position (b) by the elastic force of the return spring 30 and the weight of the loading platform 3.

Next, referring to FIG. 7, a description will be given of the loading platform lifting cylinder C1, the loading platform storing single-acting cylinder C2, and the electric circuit and hydraulic circuit for operating them.

The pump PO driven by the motor M has its suction side connected to an oil sump T, and its discharge side connected from a discharge oil line 3 to a lifting hydraulic line IT and a storage hydraulic line 2 via an electromagnetic switching valve vO. ing. In addition, the pump P
A discharge oil line 3 on the discharge side of O is also connected to the oil sump T via a relief valve VR. Further, one end side is connected to the oil sump T, and the other end side of the return oil line 0 is connected to the hydraulic line 1 for lifting and the hydraulic line for storage via the electromagnetic switching valve vO. Connected to 2. The electromagnetic switching valve VO is always held at the neutral position (the position shown in FIG. 7). And when the solenoid S is energized, the electromagnetic switching valve■
0 switches to the left position and connects the discharge line L; L3 on the discharge side of the pump PO to the lifting hydraulic line 1, and connects the return oil inlet 0 to the storage hydraulic line 2 81
held in position. When the solenoid Sr is energized, the switching valve VO is switched to the right position, connecting the discharge line 3 on the discharge side of the pump PO to the storage hydraulic line 2, and connecting the lifting hydraulic line 1 to the return oil. It is adapted to be held in a second position connected to line fLO.

The lifting hydraulic line exchange 1 includes an electromagnetic switching valve Vl with a check valve.
is provided. When this solenoid switching valve with check valve v1 is not energized, it is held at a first position where the hydraulic oil from the electromagnetic switching valve VO is supplied to the loading platform lifting cylinder Ct via the built-in check valve. When it is energized, it moves to the left position in FIG. 7 and is held at a second position where the hydraulic oil from the cargo platform lifting cylinder Ct is returned to the electromagnetic switching valve 0.

The storage hydraulic line 2 includes an electromagnetic switching valve v with a check valve.
2 is provided. When this electromagnetic switching valve v2 with a check valve is not energized, it is held in the first position where the hydraulic oil from the electromagnetic switching valve vO is supplied to the single-acting cylinder C2 for storing the loading platform via the built-in check valve. When energized, it switches to the used position in Figure 7, and the single-acting cylinder C2 for storing the loading platform is activated.
The valve is held in a second position where hydraulic oil from the valve is returned to the solenoid switching valve vO.

Line 4 is a suction line branched from the lifting hydraulic line line 1 and connected to the oil sump T, and a check valve 34 is provided in the middle to allow the flow of hydraulic oil from the oil sump T to the lifting hydraulic line 11. ing.

Reference numeral 41 denotes a pilot line that integrates the lifting hydraulic line 1 and the pilot chamber on the right side of the solenoid valve V2 with a check valve.

In addition, 35 is an open/close switch, 31 is an up/down switch, 37 is a main switch, 38 is a normally closed limit switch, and 39
is a relay, and 40 is a power supply.

In the embodiment of the present invention having the above-mentioned configuration, when the up/down switch 31 is pressed, the electromagnetic switching valve vO is held in the first position, the relay 39 is connected, the pump PO is activated, and the cargo receiving platform is opened. The lifting cylinder C1 is extended. At this time, the rotating shaft 7 rotates clockwise in FIG. 1 together with an arm fixed on the rotating shaft 7. At this time,
Both the tension link 16 and the bending compression link 11 of the parallel link mechanism rotate upward, and their tips rise, and the load receiving platform 3 is placed in the raised position shown in FIG.
b) is maintained. In this way, when the third cargo receiver is in the raised position (b), when the close switch of the open/close switch 35 is pressed, the solenoid switching valve vO goes to the second position, and the solenoid switching valve with check valve Vl goes to the second position. Then, as the pump PO operates and the lifting hydraulic line IT communicates with the oil sump T as shown in Figure 4, the receiving platform will lower slightly under its own weight to the position (d) and the receiving platform will be retracted. The loading cylinder C2 extends and the loading platform 3 rotates around the support shaft 17, and the rotating shaft 7 rotates clockwise via the cylinder bracket 24, raising the loading deck 3 to the vertical storage position. It is held in (c).

Next, when the open switch of the open/close switch 35 is pressed, the solenoid switching valve with check valve v1 is in the second position, and the cargo platform lifting cylinder CI
is communicated with the oil sump T, and the solenoid valve with reversal valve v2 is also in the second position, so that the cargo storage cylinder C2 is also communicated with the oil sump T.

By communicating the loading platform lifting cylinder C1 and the loading platform storage cylinder C2 with the oil sump, the loading platform 3 lowers a little due to its own weight, kicks the limit switch 38, opens the limit switch 38, and closes the solenoid valve with a check valve. The lowering of the loading platform 3 is stopped with Vl set to the first position.

Furthermore, since the loading platform storage cylinder C2 is in communication with the oil sump T, the storage single-acting cylinder C2 is subjected to a force in the contraction direction due to the elastic force of the return spring 30 at the same time as the above-mentioned operation.

The hydraulic oil in the cylinder C2 is connected to the storage hydraulic line KL2.
Solenoid switching valve with check valve V2. Returns to the oil sump through the electromagnetic switching valve ■0 and the return oil line fLO. Then, the single-acting cylinder C2 for storing the loading platform contracts, and the loading platform 3 begins to rotate around the support shaft 17 from a vertical position to a horizontal position. When the loading platform 3 rotates from a vertical position to an inclined position, a rotational moment due to its own weight acts on the loading platform 3. Therefore, from this point on, due to the rotational moment and the action of the return spring 30, the single-acting cylinder C2 for storing the cargo tray is contracted, and the cargo tray 3 is held in the horizontal position (d).

Next, when the up switch of the up/down switch 36 is pressed, the loading platform 3 is raised and held at the use position.

Next, when lifting and lowering the loading platform 3 to load and unload cargo, the loading platform 3 is grounded on the ground La, as shown in FIG. In order to make it easier to load and unload cargo by landing it on the ground La, the weight of the cargo receiving platform 3 is used.

The bending compression link 11 consisting of the compression link arm 9 and the compression link 10 is bent downward convexly while swinging the connecting link 19 around the support axis, and can tilt the loading platform 3 forward and downward as shown by the chain line. .

Next, as shown in FIG. 3, when lowering the loading platform 3 from the storage position (c) of the loading box 2 to the grounded position (e), press the down switch of the up/down switch 36 and the two check valves will open. The attached solenoid valves V1 and V2 are both in the second position, and both the cylinder C1 for raising and lowering the loading platform and the cylinder C2 for storing the loading platform communicate with the oil sump T.

Embodiments of the present invention will be described below based on the drawings. Then, the loading platform 3 begins to descend, and the loading platform 3 begins to rotate from the vertical position to the horizontal position due to the elastic force of the return spring 30, and when it rotates to an inclined position, the rotation moment due to the weight of the loading platform 3 is applied. With the addition of this action, it passes through the (H') position and (H'') position to reach the (A) position, and then becomes the (E) position only due to the action of the rotational moment due to the weight of the loading platform 3 and the like.

By the way, you only need to operate the switch once during the above work.
There is no need to perform the operation three times as in the past.

Next, place the loading platform 3 in the position (E) where it touches the ground to the loading box 2.
When raising to the storage position (c), open/close switch 35
When the open switch is pressed, the solenoid switching valve VO goes to the second position, the solenoid switching valve with check valve ■1 also goes to the second position, and the pump P
O is activated, and the cylinder C2 for storing the loading platform is finely moved to the third position.
As shown in the figure, the loading platform 3 begins to rotate clockwise around the support shaft 17 from the position (E), and the rotating shaft 7 rotates clockwise via the cylinder bracket 24 to receive the loading platform. Platform 3 rises to (a) position, (to'') position,
It passes through the position (f') and is held at the storing position (c) of the cargo box 2. At this time, the loading platform elevating cylinder C1 receives a load in the direction of extension, and as a result of negative pressure in the cylinder C1, the hydraulic oil in the oil reservoir T is supplied into the cylinder C1 through the suction line 4.

Further, when the loading platform 3 reaches the vertical position before the loading box 2 is placed in the storage position (c), the stopper member 33 of the loading platform 3 comes into contact with the connecting link 19 to prevent further rotation.

By the way, the switch operation during the above-mentioned work is performed only once, and there is no need to operate the switch three times as in the conventional case.

Next, as shown in Figure 6, when loading and unloading cargo on a slope, etc., the loading platform 3 is installed with the front up. If this happens, the cargo will rise at an incline, so there is a risk that it will fall off during the rise, but in the case of the present invention, when the up switch of the up/down switch 36 is pressed, the electromagnetic switching valve vO goes to the first position, and the pump PO operates, and the hydraulic oil in the oil reservoir T passes through the lifting line 26 1 and reaches the loading platform lifting cylinder C1.
As the vehicle enters the interior, the pilot line 41 causes the electromagnetic switching valve v2 with a check valve to move to the second position, the loading platform storage cylinder C2 communicates with the oil sump T, and the loading platform 3 rotates counterclockwise. Since the cargo rises in a horizontal state as indicated by the solid line, the cargo will not fall during the rise.

(f) Effects of the Invention As described above, according to the present invention, a rotary shaft rotatably driven by a cylinder for raising and lowering the loading platform is rotatably provided on the vehicle body frame, and a bendable compression link is fixed to the rotary shaft. In addition, the base end of the tension link is pivotally supported on the vehicle body frame.
A loading platform is pivotally supported at the tip of the tension link so that it can be raised and lowered,
At the tip of the bending compression link, the other end of a connecting link whose one end is connected to the shaft support of the tension link and the loading platform is pivotally supported. Since it is pivotally supported on a cylinder bracket fixed to the rotating shaft, it can be used to lower a loading platform that is in the storage position of a cargo box to a position where it is on the ground, or to raise a loading platform that is in a position that is in contact with the ground to the storage position of a cargo box. In order to do this, each operation only needs to be performed once, and there is no need to perform the operations many times as in the past, so the burden on the operator is reduced.

5 and 6 are side views showing the loading platform in a moving state, and FIG. 7 is an electric and hydraulic circuit diagram.

1. Vehicle body frame, 3. Loading platform, 7. Rotating shaft, 1
1... Refraction compression link, 16... Tension link.

19...Connection link, 24...Cylinder bracket, C
I: Cylinder for lifting the loading platform, C2: Cylinder for storing the loading platform

Claims (1)

[Claims] A rotary shaft rotatably driven by a cylinder for raising and lowering the loading platform is rotatably provided on the vehicle body frame, a bendable bending compression link is fixed to the rotary shaft, and the base end of the tension link is pivotally supported on the vehicle body frame. , a loading platform is rotatably supported at the tip of the tensioning link, and the other end of a connecting link, the other end of which connects the tensioning link to a pivoting support with the loading platform, is pivotally supported at the tip of the bending compression link. and a loading platform lifting/lowering device, further comprising: a base portion of a loading platform storage cylinder for raising and lowering the loading platform being pivotally supported by a cylinder bracket fixed to the rotating shaft;