JP2024093263A - Loading platform lifting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loading platform lifting device which allows an operator to easily perform adjustment work when the operator adjusts the highest elevation position of a loading platform.

SOLUTION: A loading platform lifting device 10 includes: a pair of left and right columns 20 which is installed in a standing manner on both sides of a rear end of a load-carrying platform 1 of a truck vehicle; a pair of left and right first arms 40; a pair of left and right second arms 50; an inter-arm connection member 60 which is rotatably connected to a tip side of the first arm and rotatably connected to a tip side of the second arm at a position lower than the connection position with the first arm; a loading platform 70 which is rotatably connected to the inter-arm connection member; a cylinder 80 which raises/lowers the loading platform 70; and loading platform highest elevation position adjustment means 25 which forms an interposed part 26 that defines a minimum value of the interval between the inter-arm connection member and the column by being interposed between the inter-arm connection member 60 and the column 20 and is configured to be able to adjust the interposition dimension of the interposed part 26 such that the minimum value can be adjusted.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a loading platform lifting device.

A loading platform lifting device that is attached to the rear of a truck vehicle and raises and lowers the loading platform between the ground and the platform is known to use two arms that form a link mechanism (see, for example, Patent Document 1).

In the load-receiving platform uppermost position adjustment device in the load-receiving platform lifting device described in Patent Document 1, the abutment member (25) provided below the load-receiving platform (2) abuts against the abutment portion (15a) provided at the base end of the upper link (15), thereby restricting the lifting of the load-receiving platform (12). The abutment member (25) is screwed to a mounting bracket (11) fixed to the vehicle body below the load-receiving platform (2), and its position can be changed in the axial direction relative to the bracket (11). Changing the position of the abutment member (25) in the axial direction moves the abutment position between the abutment member (25) and the abutment portion (15a) of the upper link (15), thereby making it possible to adjust the uppermost position of the load-receiving platform (12).

JP 2000-255304 A

When adjusting the highest position of the load receiving platform (12), the work of moving the contact position of the contact member (25) must be performed while checking both the contact position where the contact member (25) contacts the contact portion (15a) of the upper link (15) and the highest position of the load receiving platform (12).

However, because the abutment member (25) is provided below the loading platform (2), the loading platform (25) and the abutment member (25) are visually located apart from each other. This means that the worker must adjust the uppermost position of the loading platform (25) by moving the abutment member (25) in the axial direction while alternately checking the uppermost position of the loading platform (25) and the abutment position of the abutment member (25). In other words, there is a problem in that the adjustment work becomes complicated.

The present invention was devised in consideration of the above problems, and aims to provide a loading platform lifting device that can easily adjust the topmost position of the loading platform.

The load receiving platform lifting device according to the first aspect of the present invention comprises a support member fixed to the vehicle side, a pair of left and right first arms whose base ends are rotatably connected to the support member, a pair of left and right second arms arranged at a lower position than the first arms and whose base ends are rotatably connected to the support member, a pair of left and right inter-arm connecting members rotatably connected to the tip ends of the first arms and rotatably connected to the tip ends of the second arms at a lower position than the connection position with the first arms, a load receiving platform rotatably connected to the inter-arm connecting members, and a cylinder for lifting and lowering the load receiving platform, wherein the support member, the first arms, the second arms, and the inter-arm connecting members form a parallel link mechanism. In the loading platform lifting device, the cylinder drives the first arm or the second arm to lift the loading platform while maintaining its position, the support members are a pair of left and right pillars erected on both sides of the rear end of the loading platform of the vehicle, the parallel link mechanism is configured so that the higher the loading platform is, the closer the inter-arm connecting member is to the pillars, and the loading platform highest position adjustment means is further provided, which is interposed between the inter-arm connecting member and the pillar to form an interposition part that determines the minimum value of the gap between the inter-arm connecting member and the pillar, and is configured so that the interposition dimension of the interposition part can be adjusted to adjust the minimum value.

With a load-receiving platform lifting device having such a configuration, the uppermost position of the load-receiving platform can be adjusted by adjusting the dimension of the intermediate part that is interposed between the inter-arm connecting member and the support. And because both the intermediate part and the load-receiving platform are located near the inter-arm connecting member, the worker can adjust the uppermost position of the load-receiving platform while simultaneously checking the dimension of the intermediate part and the height position of the load-receiving platform in the same field of vision. As a result, the adjustment work can be performed easily.

The loading platform lifting device according to the second aspect of the present invention is the loading platform lifting device according to the first aspect, in which the cylinder has one end rotatably connected to the support and the other end rotatably connected to the first arm, and the loading platform highest position adjustment means is configured such that the interposition portion is formed between the vicinity of the upper end of the inter-arm connecting member and the support.

In a loading platform lifting device having such a configuration, the intermediate portion of the loading platform highest position adjustment means is configured to be formed between the vicinity of the upper end of the inter-arm connecting member and the support pillar, so that it is possible to prevent the posture of the inter-arm connecting member and the loading platform from being disturbed at the highest position, compared to, for example, a case in which the intermediate portion is formed between the vicinity of the lower end of the inter-arm connecting member and the support pillar.

The loading platform lifting device according to the third aspect of the present invention is the loading platform lifting device according to the first or second aspect, and the loading platform highest position adjustment means includes an abutment member having a male threaded portion that is threadedly attached to one of the support pillar and the arm connecting member and is movable toward the other of the support pillar and the arm connecting member, and an abutment portion that abuts against one of the support pillar and the arm connecting member.

With a loading platform lifting device having such a configuration, the adjustment of the interposition dimension of the interposition part formed by the loading platform highest position adjustment means can be performed by rotating the male threaded part relative to the support side or inter-arm connecting member side to which the male threaded part is screwed, so that the worker can easily adjust the highest position of the loading platform.

The fourth aspect of the present invention is a loading platform lifting device according to the third aspect, in which the loading platform highest position adjustment means further includes a nut screwed onto the male threaded portion.

With a loading platform lifting device having such a configuration, the nut threaded onto the male threaded portion is tightened so that it approaches the portion where the male threaded portion is threaded onto the support or inter-arm connecting member, thereby preventing the male threaded portion from rotating, and thus preventing the interposition dimension of the interposition portion from unintentionally increasing or decreasing.

The present invention provides a loading platform lifting device that can easily adjust the topmost position of the loading platform.

1 is a perspective view of a loading platform lifting device according to an embodiment of the present invention; 1 is a side view of a load-receiving platform lifting and lowering device according to an embodiment of the present invention, with a broken line drawn at approximately the middle position in the height direction in order to show the inside of a support column (support member). 3 is an enlarged view of part A in Fig. 2. In order to show the platform highest position adjustment means, a broken line is drawn near the upper end of the inter-arm connecting member. 1 is a side view of a load-receiving platform lifting device according to an embodiment of the present invention, showing a state in which the load-receiving platform is located near the ground. 1 is a side view of a load-receiving platform lifting device according to an embodiment of the present invention, showing a state in which the load-receiving platform is in the highest position; 1A is a schematic side view of a loading platform lifting device according to an embodiment of the present invention, in which (a) shows a case in which a loading platform highest position adjustment means is provided near the lower end of the arm connecting member, and (b) shows a case in which a loading platform highest position adjustment means is provided near the upper end of the arm connecting member. 3 is a view equivalent to an enlarged view of part A in FIG. 2, showing a platform uppermost position adjustment means of a platform lifting and lowering device according to a modified example of the present invention. FIG.

The load receiving platform lifting device 10 according to an embodiment of the present invention will be described below with reference to the drawings. Note that in this specification, the front, rear, up, down, left and right directions are defined based on the truck vehicle (not shown) on which the load receiving platform lifting device 10 is mounted.

As shown in Figures 1 and 2, the loading platform lifting device 10 is attached to the loading platform 1 of a truck vehicle (not shown). The loading platform lifting device 10 is composed of a support 20, a loading platform highest position adjustment means 25, a cross member 30, a first arm 40, a second arm 50, an inter-arm connecting member 60, a loading platform 70, a cylinder 80, a power unit 90, etc.

The pillars 20 are arranged in a pair on the left and right in parallel with each other and erected on both sides of the rear end of the bed 1 of the truck vehicle. In other words, the pillars 20 are fixed to the truck vehicle side. The pillars 20 are support members that rotatably support the first arm 40 and the second arm 50. The pillars 20 are hollow, with the upper side formed into a roughly square tube shape and the lower side formed into a roughly U-shaped cross section that opens to the rear.

The cross member 30 is installed between a pair of left and right pillars 20. The top surface of the cross member 30 forms the same plane as the floor surface 1a of the cargo bed 1. The front surface of the cross member 30 forms the same plane as the front surface of the pillars 20. There are no protrusions on the front surface of the cross member 30 or the front surface of the pillars 20.

The first arms 40 are provided in a pair on the left and right. The base ends 41 of the first arms 40 are disposed inside the support pillars 20 and are rotatably connected to the pair of left and right support pillars 20. Specifically, the base ends 41 of the first arms 40 and the support pillars 20 are rotatably connected to each other via an axis member 42 that passes through the base ends 41 of the first arms 40 and the support pillars 20 in the vehicle width direction.

The second arm 50 is disposed at a lower position than the first arm 40. A pair of second arms 50 are provided on the left and right sides. The base end portion 51 of the second arm 50 is disposed inside the support pillar 20 and is rotatably connected to each of the pair of left and right support pillars 20. Specifically, the base end portion 51 of the second arm 50 and the support pillar 20 are rotatably connected to each other via an axis member 52 that penetrates the base end portion 51 of the second arm 50 and the support pillar 20 in the vehicle width direction.

As shown in FIG. 2, a connecting pipe 55 is installed between the pair of left and right second arms 50. The connecting pipe 55 is provided at a predetermined position between the center of rotation of the second arm 50 relative to the support 20 and the center of rotation relative to the inter-arm connecting member 60.

The inter-arm connecting members 60 are provided in a pair on the left and right sides, and as shown in FIG. 2, their upper end 62 side is rotatably connected to the tip 43 side of the first arm 40 via a shaft member 44, and their lower end 61 side is rotatably connected to the tip 53 side of the second arm 50 via a shaft member 54 at a position lower than the connection position with the first arm 40.

As is clear from the above description, the support pillar 20, the first arm 40, the second arm 50, and the inter-arm connecting member 60 form a parallel link mechanism. As shown in Figures 4 and 5, the parallel link mechanism is configured such that the inter-arm connecting member 60 approaches the support pillar 20 the higher the loading platform 70 is positioned.

The load-receiving platform highest-rise position adjustment means 25 adjusts the minimum distance between the arm-to-arm connecting member 60 and the support 20 to adjust the highest-rise position of the arm-to-arm connecting member 60 and the load-receiving platform 70.

As shown in FIG. 3, the load-receiving platform highest position adjustment means 25 has a female threaded portion provided on the inter-arm connecting member 60, a bolt 27 screwed into the female threaded portion, and a fixing nut 29 screwed into the bolt 27.

The female thread is formed by a female thread nut 28 fixed to the rear surface of the front wall 60f of the inter-arm connecting member 60. In addition, a through hole 60fh for inserting the bolt 27 is formed at a position concentric with the female thread of the front wall 60f.

The bolt 27 has a male threaded portion 27a, which is a screw shaft, and a head portion 27b provided at the end of the male threaded portion 27a. The head portion 27b of the bolt 27 constitutes the abutment member 27, which serves as the abutment portion 27b that abuts against the rear side of the support 20. A reinforcing plate 20b fixed to the support body 20a is provided at the portion of the support 20 where the abutment portion 27b abuts. The reinforcing plate 20b is provided to prevent damage to the rear wall of the support 20 due to a collision with the abutment portion 27b of the abutment member 27.

The abutment member 27 rotates relative to the female thread nut 28 into which the male thread portion 27a is screwed, thereby moving axially toward the support 20.

The abutment member 27 forms an intermediate portion 26 that is interposed between the support 20 and the inter-arm connecting member 60. By forming the intermediate portion 26, the abutment member 27 determines the minimum distance between the inter-arm connecting member 60 and the support 20. In this embodiment, the intermediate portion 26 is formed between the support 20 and the vicinity of the upper end portion 62 of the inter-arm connecting member 60.

The interposition portion 26 is formed by the abutment portion 27b of the abutment member 27 and the portion of the male thread portion 27a exposed from the inter-arm connecting member 60. This allows the minimum value of the gap between the support 20 and the inter-arm connecting member 60, which is the gap dimension L of the interposition portion 26, to be adjusted by rotating the abutment member 27 about its axis in either direction.

As shown in FIG. 2, the load receiving platform 70 is rotatably connected to the inter-arm connecting member 60. Specifically, the base end of the load receiving platform 70 is rotatably connected to the inter-arm connecting member 60 at a position lower than the connection part of the inter-arm connecting member 60 with the second arm 50. The load receiving platform 70 is configured to be rotatable relative to the inter-arm connecting member 60 within a range from a vertical position in the stored state to a horizontal position in the deployed state.

For this reason, as shown in FIG. 2, the load receiving platform lifting device 10 is configured so that the pair of left and right inter-arm connecting members 60 and the load receiving platform 70 can be brought close to and parallel with the pair of left and right support columns 20 when the cylinder 80 is contracted.

A locking lever 72 is attached to the side of the cargo receiving platform 70. As shown in FIG. 2, the locking lever 72 engages with the locking lever receiving portion 22 attached to the support 20, thereby locking the cargo receiving platform 70 in the stored state and preventing the cargo receiving platform 70 from being accidentally deployed in the stored state.

As shown in FIG. 4, a loading platform support member 75 is installed between the side of the loading platform 70 and the side of the arm connecting member 60. Both ends of the loading platform support member 75 are rotatably connected to the side of the loading platform 70 and the side of the arm connecting member 60, respectively. The middle part of the loading platform support member 75 is bendable. As a result, when the loading platform 70 is unfolded and in a horizontal position, the loading platform support member 75 prevents the loading platform 70 from rotating any further and supports the loading platform 70. When the loading platform 70 is in a stored state, the loading platform support member 75 is bent at the middle part and positioned so as to overlap the loading platform 70.

As shown in FIG. 2, the cylinder 80 is disposed inside the support 20, extending in the height direction. The upper end 83 of the cylinder 80 is rotatably connected to the upper end of the support 20 via an axis member 84. The lower end 81 of the cylinder 80 is rotatably connected to approximately the middle of the first arm 40 via an axis member 82. The cylinder 80 drives the first arm 40 to raise and lower the loading platform 70 while maintaining the position of the loading platform 70.

The position of the shaft member 84, which is the connecting position that rotatably connects the upper end 83 side of the cylinder 80 to the support 20, is set at a higher position than the position of the shaft member 42, which is the rotation center position of the base end 41 side of the first arm 40. As a result, the cylinder 80 applies a driving force (cylinder thrust) to the first arm 40 from above the first arm 40.

The power unit 90 supplies and discharges hydraulic oil to the cylinder 80 through piping (not shown). The power unit 90 is provided inside the cross member 30, as shown in FIG. 2.

A bumper member 100 is installed between the lower ends of the pair of left and right pillars 20.

As shown in FIG. 2, an inverted L-shaped reinforcing member 110 is joined so as to contact the portion of the support pillar 20 that extends downward from the loading platform 1 and the bottom surface of the loading platform 1 that is perpendicular to the portion. The reinforcing member 110 reinforces the joint between the support pillar 20 and the rear end of the loading platform 1.

An operation button 120 is provided on the side of the support 20 to be operated to raise or lower the loading platform 70. When the operation button 120 is operated, the power unit 90 is activated, and the loading platform 70 is raised or lowered by the power unit 90.

Next, the operation of the loading platform lifting device 10 will be described. When lifting cargo on a truck vehicle, the loading platform 70 is deployed to a horizontal position as shown in FIG. 4, and the cylinder 80 is extended to bring the platform into a grounded position.

When performing a lifting operation, the worker places the luggage (not shown) on the cargo receiving platform 70, and then operates the operation button 120 to retract the cylinder 80. This causes the tip 43 of the first arm 40 to rise together with the tip 53 of the second arm 50 and the arm connecting member 60, and the cargo receiving platform 70 connected to the arm connecting member 60 also rises to near the height of the floor surface 1a of the cargo platform 1 while maintaining a horizontal position. This state is shown in FIG. 5.

When unloading luggage from the loading platform 1, the loading platform lifting device 10 performs the reverse of the above.

Next, the procedure for adjusting the highest position of the loading platform 70 will be explained with reference to Figure 5.

In Figure 5, the positions of the arm-to-arm connecting member 60 and the load receiving platform 70 shown by solid lines indicate the highest positions of the arm-to-arm connecting member 60 and the load receiving platform 70 when the intervention dimension L (see Figure 3) of the intervention part 26 of the load receiving platform highest position adjustment means 25 is small. In Figure 5, the positions of the arm-to-arm connecting member 60 and the load receiving platform 70 shown by two-dot chain lines indicate the highest positions of the arm-to-arm connecting member 60 and the load receiving platform 70 when the intervention dimension L of the intervention part 26 of the load receiving platform highest position adjustment means 25 is large.

The parallel link mechanism is configured so that the higher the load receiving platform 70 is, the closer the inter-arm connecting member 60 is to the support pillar 20. Therefore, when the intervening dimension L of the intervening portion 26 between the intervening portion 60 and the support pillar 20 is relatively small, the uppermost position of the load receiving platform 70 is relatively high, as shown by the solid line in FIG. 5. On the other hand, when the intervening dimension L of the intervening portion 26 is relatively large, the uppermost position of the load receiving platform 70 is relatively low, as shown by the two-dot chain line in FIG. 5.

Therefore, the highest position of the load receiving platform 70 can be adjusted by adjusting the interposition dimension L of the interposition portion 26 that is interposed between the inter-arm connecting member 60 and the support 20. Specifically, the highest position of the load receiving platform 70 can be adjusted by rotating the abutment member 27 about its axis in either direction.

<Action and effect>
According to the load-receiving platform lifting device 10 of the present embodiment described above, the uppermost position of the load-receiving platform 70 can be adjusted by adjusting the interposition dimension L of the interposition portion 26 interposed between the arm-to-arm connecting member 60 and the support column 20. Since both the interposition portion 26 and the load-receiving platform 70 are located near the arm-to-arm connecting member 60, the worker can adjust the uppermost position of the load-receiving platform 70 while simultaneously checking the interposition dimension L of the interposition portion 26 and the height position of the load-receiving platform 70 within the same field of vision. As a result, the adjustment work can be easily performed.

In addition, according to the load-receiving platform lifting device 10, the interposition portion 26 of the load-receiving platform highest position adjustment means 25 is configured to be formed between the vicinity of the upper end portion 62 of the arm-to-arm connecting member 60 and the support column 20, so that the posture of the arm-to-arm connecting member 60 and the load-receiving platform 70 at the highest position can be prevented from being disturbed, compared to, for example, a case in which the interposition portion 26 is formed between the vicinity of the lower end portion 61 of the arm-to-arm connecting member 60 and the support column 20.

This point will be explained in detail with reference to FIG. 6. As shown in FIG. 6(a), even when the intermediate portion 26 of the load-receiving platform highest position adjustment means 25 is formed between the vicinity of the lower end portion 61 of the inter-arm connecting member 60 and the support 20, the cylinder thrust applied by the cylinder 80 to the first arm 40 is transmitted from the first arm 40 to the inter-arm connecting member 60. Here, the connecting portion (shaft member 44 in FIG. 2) between the first arm 40 and the inter-arm connecting member 60 is located relatively far from the intermediate portion 26. The cylinder thrust is a vector directed to the upper left of the figure due to the connection relationship between the cylinder 80 and the first arm 40, and a moment of force that tries to rotate the inter-arm connecting member 60 counterclockwise in the figure around the intermediate portion 26 is applied to the inter-arm connecting member 60. At the same time, because the cylinder 80 is connected to the first arm 40 at approximately the middle position in the longitudinal direction of the first arm 40, the cylinder thrust causes bending deformation of the first arm 40 so that it curves toward the upper left in the figure. When bending deformation occurs in the first arm 40, the distance between the connection portion (shaft member 42 in FIG. 2 ) between the first arm 40 and the support 20 and the connection portion (shaft member 44 in FIG. 2 ) between the first arm 40 and the arm connecting member 60 becomes shorter. When this distance becomes shorter, the arm connecting member 60 rotates counterclockwise in the figure around the intermediate portion 26. In this way, when the intermediate portion 26 of the load-receiving platform highest position adjustment means 25 is formed near the lower end portion 61 of the arm-to-arm connecting member 60 and the support column 20, the action of the force moment generated in the arm-to-arm connecting member 60 and the action of the bending deformation generated in the first arm 40 combine to cause the arm-to-arm connecting member 60 and the load-receiving platform 70 to lose their position and rotate counterclockwise as shown in FIG. 6(a).

On the other hand, as shown in FIG. 6(b), when the intermediate portion 26 of the load-receiving platform highest position adjustment means 25 is formed between the vicinity of the upper end portion 62 of the inter-arm connecting member 60 and the support 20, the connecting portion (shaft member 44 in FIG. 2) between the first arm 40 and the inter-arm connecting member 60 is located relatively close to the intermediate portion 26. As a result, even if the cylinder thrust transmitted to the inter-arm connecting member 60 and directed toward the upper left of the figure generates a force moment that tends to rotate the inter-arm connecting member 60 clockwise around the intermediate portion 26, the magnitude of the force moment is smaller than the magnitude of the force moment in the case of FIG. 6(a), and the force received by the second arm 50 is also small, so it is almost impossible to imagine that the second arm 50 will deform and the inter-arm connecting member 60 will rotate clockwise. In addition, when the intermediate portion 26 is formed between the vicinity of the upper end portion 62 of the inter-arm connecting member 60 and the support 20, the first arm 40 will hardly be bent and deformed by the cylinder thrust. Therefore, when the intermediate portion 26 of the load-receiving platform highest position adjustment means 25 is formed between the upper end 62 of the arm-to-arm connecting member 60 and the support column 20, the arm-to-arm connecting member 60 and the load-receiving platform 70 are prevented from being distorted so that they rotate clockwise in the figure.

In addition, with the load-receiving platform lifting device 10, the highest position of the load-receiving platform 70 can be adjusted simply by rotating the abutment member 27 in either direction, making this adjustment easy.

In addition, with the loading platform lifting device 10, the fixing nut 29 can be tightened toward the inter-arm connecting member 60 to prevent the abutment member 27 from rotating due to vibrations, etc., while the truck vehicle is traveling, thereby preventing the intervention dimension L of the intervention portion 26 from increasing or decreasing unintentionally.

(Modification)
In the above-mentioned loading platform lifting device 10, the female threaded portion for screwing in the male threaded portion 27a of the bolt 27, which is the abutment member, is formed by a female thread nut 28 fixed to the front wall 60f of the arm-to-arm connecting member 60. However, it is also possible to form a female threaded portion 60fhA in the through hole 60fh of the arm-to-arm connecting member 60 without providing a female thread nut 28 (see Figure 7).

In addition, in the above-mentioned loading platform lifting device 10, the head 27b (abutment portion 27b) of the bolt 27, which is the abutment member, has been described as abutting against the reinforcing plate 20b fixed to the rear surface of the support body 20a. However, as shown in FIG. 7, the head 27b of the bolt 27 may be made to abut directly against the rear surface of the support body 20a without providing a reinforcing plate 20b on the rear surface of the support body 20a.

In addition, in the above-mentioned loading platform lifting device 10, the loading platform highest position adjustment means 25 has been described as being provided on the inter-arm connecting member 60 side, but the loading platform highest position adjustment means 25 may be provided on the support 20 side. In other words, the loading platform highest position adjustment means 25 may be configured so that the male threaded portion 27a of the bolt 27, which is the abutment member, is screwed into the support 20 side, and the head portion 27b abuts against the front surface of the front wall 60f of the inter-arm connecting member 60.

In addition, in the above-mentioned loading platform lifting device 10, the lower end 81 of the cylinder 80 has been described as being rotatably connected to the first arm 40, but it may also be rotatably connected to the second arm 50.

The present invention can be applied, for example, to a loading platform lifting device.

1 Loading platform 10 Loading platform lifting device 20 Support (support member)
25 Load receiving platform highest position adjustment means 26 Interposition portion 27 Contact member (bolt)
27a Male thread portion 27b Contact portion (bolt head)
29 Fixing nut 40 First arm 41 Base end portion of first arm 43 Tip end portion of first arm 50 Second arm 51 Base end portion of second arm 53 Tip end portion of second arm 60 Inter-arm connecting member 70 Load receiving platform 80 Cylinder 81 Lower end of cylinder 83 Tip end of cylinder

Claims (4)

A support member fixed to a vehicle side;
A pair of left and right first arms each having a base end portion rotatably connected to the support member;
a pair of left and right second arms disposed at a lower position than the first arms and having base ends rotatably connected to the support member;
a pair of left and right inter-arm connecting members rotatably connected to a tip end side of the first arm and rotatably connected to a tip end side of the second arm at a position lower than a connecting position with the first arm;
A load receiving platform rotatably connected to the inter-arm connecting member;
A cylinder for raising and lowering the loading platform;
Equipped with
In a loading platform lifting device, the support member, the first arm, the second arm, and the arm connecting member constitute a parallel link mechanism, and the cylinder drives the first arm or the second arm to lift and lower the loading platform while maintaining the posture of the loading platform,
The support members are a pair of left and right pillars erected on both sides of a rear end of the loading platform of the vehicle,
The parallel link mechanism is configured such that the higher the load receiving platform is, the closer the inter-arm connecting member is to the support pillar,
a platform uppermost position adjustment means for adjusting a dimension of the intermediate portion between the arm connecting member and the support pillar, the intermediate portion being interposed between the arm connecting member and the support pillar to define a minimum value of the gap between the arm connecting member and the support pillar, and the platform uppermost position adjustment means is configured to be adjustable so that the minimum value can be adjusted;
A loading platform lifting device characterized by the above. 2. The loading platform lifting device according to claim 1,
The cylinder has one end rotatably connected to the support and the other end rotatably connected to the first arm,
The load-receiving platform highest-rise position adjustment means is configured so that the intermediate portion is formed between the vicinity of the upper end portion of the inter-arm connecting member and the support pillar.
A loading platform lifting device characterized by the above. The loading platform lifting device according to claim 1 or 2,
This loading platform lifting device is characterized in that the loading platform highest position adjustment means includes an abutment member having a male threaded portion screwed into the other of the support pillar and the arm-connecting member and movably toward one of the support pillar and the arm-connecting member, and an abutment portion abutting against one of the support pillar and the arm-connecting member. The load receiving platform lifting device according to claim 3,
A loading platform lifting device, characterized in that the loading platform highest position adjustment means further includes a nut screwed onto the male thread portion.

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