Loading platform lifting device

Abstract

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

Description

Technical Field

[0001] The present invention relates to a load receiving platform lifting device.

Background Art

[0002] As a load receiving platform lifting device attached to the rear of a truck vehicle and lifting the load receiving platform between the ground and the platform, a device using two arms constituting a link mechanism is known (for example, see Patent Document 1).

[0003] In the uppermost lifting position adjusting device of the load receiving platform in the load receiving platform lifting device described in Patent Document 1, the contact member (25) provided below the platform (2) contacts the contact portion (15a) provided at the base end portion of the upper link (15), thereby restricting the upward movement of the load receiving platform (12). The contact member (25) is screwed to a mounting bracket (11) fixed to the vehicle body side below the platform (2), and its position can be changed in the axial direction with respect to the bracket (11). By changing the position of the contact member (25) in the axial direction, the contact position between the contact member (25) and the contact portion (15a) of the upper link (15) moves, and thereby the uppermost lifting position of the load receiving platform (12) can be adjusted.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When adjusting the uppermost lifting position of the load receiving platform (12), the operation of moving the contact position of the contact member (25) while checking both the contact position where the contact member (25) contacts the contact portion (15a) of the upper link (15) and the uppermost lifting position of the load receiving platform (12) must be performed.

[0006] However, since the contact member (25) is located below the loading platform (2), the loading platform (25) and the contact member (25) are visually separated from each other. Therefore, the worker must adjust the loading platform (25) by moving the contact member (25) axially while alternately checking the highest position of the loading platform (25) and the contact position of the contact member (25). In other words, there is a problem that the adjustment work becomes complicated.

[0007] This invention was conceived in view of the above-mentioned problems, and aims to provide a loading platform lifting device that allows for easy adjustment of the loading platform's highest position. [Means for solving the problem]

[0008] A loading platform lifting device according to a 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 positioned lower 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 end of the first arms and rotatably connected to the tip end of the second arms at a position lower than the connection point with the first arms, a loading platform rotatably connected to the inter-arm connecting members, and a cylinder for raising and lowering the loading platform, wherein the support member, the first arms, the second arms, and the inter-arm connecting members form a parallel link mechanism. A loading platform lifting device is configured such that the loading platform can be raised and lowered while maintaining its posture by the cylinder driving the first arm or the second arm, the support members being a pair of left and right support columns erected on both sides of the rear end of the loading platform of the vehicle, the parallel link mechanism being configured such that the arm-to-arm connecting member approaches the support column as the loading platform is at a higher position, and the device further includes a loading platform highest position adjustment means which interposes between the arm-to-arm connecting member and the support column to define the minimum distance between the arm-to-arm connecting member and the support column, and whose interposing dimensions are adjustable so as to adjust the minimum value.

[0009] With a loading platform lifting device having such a configuration, the highest position of the loading platform can be adjusted by adjusting the dimensions of the intervening part that is interposed between the arm connecting member and the support column. Since both the intervening part and the loading platform are located near the arm connecting member, the operator can adjust the highest position of the loading platform while simultaneously checking the dimensions of the intervening part and the height of the loading platform within the same field of view. As a result, this adjustment work can be easily performed.

[0010] A loading platform lifting device according to a second aspect of the present invention is a loading platform lifting device according to a first aspect, wherein the cylinder is rotatably connected at one end to the support column and rotatably connected at the other end to the first arm, and the means for adjusting the highest position of the loading platform is configured such that the intervening portion is formed between the vicinity of the upper end of the connecting member between the arms and the support column.

[0011] In a loading platform lifting device having such a configuration, the intervening portion of the loading platform's highest position adjustment means is formed between the vicinity of the upper end of the inter-arm connecting member and the support column. Therefore, compared to, for example, the case where the intervening portion is formed between the vicinity of the lower end of the inter-arm connecting member and the support column, it is possible to suppress disturbances in the posture of the inter-arm connecting member and the loading platform at the highest position.

[0012] A loading platform lifting device according to a third aspect of the present invention is a loading platform lifting device according to the first or second aspect, wherein the means for adjusting the highest position of the loading platform includes a contact member having a male screw portion screwed to the other of the support column and the arm connecting member so as to be movable toward one of the support column and the arm connecting member, and a contact portion that contacts the one of the support column and the arm connecting member.

[0013] With a loading platform lifting device having such a configuration, the intervening dimensions of the intervening part formed by the loading platform's highest position adjustment means can be adjusted by rotating the male screw part relative to the support column side or the arm-to-arm connecting member side to which the male screw part is screwed, so that the operator can easily adjust the highest position of the loading platform.

[0014] A fourth aspect of the present invention is a loading platform lifting device according to the third aspect, wherein the means for adjusting the highest position of the loading platform further includes a nut screwed onto the male screw portion.

[0015] In a loading platform lifting device having such a configuration, the rotation of the male thread is prevented by tightening the nut screwed onto the male thread so that it approaches the portion where the male thread is screwed onto the support column or the connecting member between arms, thereby preventing the intervening dimensions of the intervening part from unintentionally increasing or decreasing. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a loading platform lifting device that allows for easy adjustment of the loading platform's highest position. [Brief explanation of the drawing]

[0017] [Figure 1] This is a perspective view of a loading platform lifting device according to an embodiment of the present invention. [Figure 2] This is a side view of a loading platform lifting device according to an embodiment of the present invention. A break line is drawn at approximately the midpoint in the height direction to show the inside of the support column (support member). [Figure 3] This is an enlarged view of section A in Figure 2. A break line has been added near the upper end of the connecting member between the arms to show the mechanism for adjusting the highest position of the loading platform. [Figure 4] This is a side view of a loading platform lifting device according to an embodiment of the present invention, showing the loading platform in a state near the ground. [Figure 5] This is a side view of a loading platform lifting device according to an embodiment of the present invention, showing the loading platform in its highest position. [Figure 6]It is a schematic side view of a load-carrying platform lifting device according to an embodiment of the present invention. (a) shows a case where the load-carrying platform uppermost position adjusting means is provided near the lower end of the inter-arm connecting member, and (b) shows a case where the load-carrying platform uppermost position adjusting means is provided near the upper end of the inter-arm connecting member. [Figure 7] It is a figure corresponding to the enlarged view of part A of FIG. 2, and is a figure showing the load-carrying platform uppermost position adjusting means of the load-carrying platform lifting device according to a modification of the present invention.

Embodiments for Carrying out the Invention

[0018] Hereinafter, the load-carrying platform lifting device 10 according to the embodiment of the present invention will be described with reference to the drawings. In this specification, the front-rear, up-down, left-right directions are defined based on a truck vehicle (not shown) to which the load-carrying platform lifting device 10 is attached.

[0019] As shown in FIGS. 1 and 2, the load-carrying platform lifting device 10 is attached to the load platform 1 of a truck vehicle (not shown). The load-carrying platform lifting device 10 is composed of a support column 20, a load-carrying platform uppermost position adjusting means 25, a cross member �0, a first arm 40, a second arm 50, an inter-arm connecting member 60, a load-carrying platform 70, a cylinder 80, a power unit 90, etc.

[0020] The support columns 20 are arranged in a pair on the left and right parallel to each other, and are erected on both side portions of the rear end of the load platform 1 of the truck vehicle. That is, the support columns 20 are fixed to the truck vehicle side. The support column 20 is a support member that rotatably supports the first arm 40 and the second arm 50 respectively. The support column 20 is hollow, the upper side is formed in a substantially square tube shape, and the lower side is formed in a substantially U-shaped cross section with an opening at the rear.

[0021] The cross member 30 is installed between the pair of left and right support columns 20. The upper surface of the cross member 30 forms the same plane as the floor surface 1a of the load platform <1>. The front surface of the cross member 30 forms the same plane as the front surface of the support column 20. Note that there are no protrusions on the front surface of the cross member 30 and the front surface of the support column 20.

[0022] The first arms 40 are provided in pairs, one on the left and one on the right. The base ends 41 of the first arms 40 are located inside the support columns 20 and are rotatably connected to the pair of support columns 20. Specifically, the base ends 41 of the first arms 40 and the support columns 20 are rotatably connected to each other via a shaft member 42 that penetrates the support columns 20 in the vehicle width direction.

[0023] The second arm 50 is positioned lower than the first arm 40. The second arm 50 is provided in a pair, left and right. The base end 51 of the second arm 50 is located inside the support column 20 and is rotatably connected to the left and right pair of support columns 20. Specifically, the base end 51 of the second arm 50 and the support column 20 are rotatably connected to each other via a shaft member 52 that penetrates the support column 20 in the vehicle width direction.

[0024] As shown in Figure 2, a connecting pipe 55 is installed between the pair of left and right second arms 50. The connecting pipe 55 is positioned at a predetermined location between the pivot point of the second arm 50 relative to the support column 20 and the pivot point of the inter-arm connecting member 60.

[0025] The arm-to-arm connecting members 60 are provided in pairs, left and right. As shown in Figure 2, their upper ends 62 are rotatably connected to the tip 43 of the first arm 40 via a shaft member 44, and their lower ends 61 are rotatably connected to the tip 53 of the second arm 50 via a shaft member 54 at a position lower than the connection point with the first arm 40.

[0026] As is clear from the above description, the support column 20, the first arm 40, the second arm 50, and the inter-arm connecting member 60 constitute 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 column 20 as the load-receiving platform 70 is at a higher position.

[0027] The load receiving platform's highest position adjustment means 25 adjusts the highest position of the arm connecting member 60 and the load receiving platform 70 by adjusting the minimum distance between the arm connecting member 60 and the support column 20.

[0028] As shown in Figure 3, the load receiving platform's highest position adjustment means 25 includes a female threaded portion provided on the arm-to-arm connecting member 60, a bolt 27 screwed into the female threaded portion, and a fixing nut 29 screwed onto the bolt 27.

[0029] The female thread portion is formed by a female thread nut 28 fixed to the rear surface of the front wall 60f of the arm connecting member 60. In addition, a through hole 60fh for inserting a bolt 27 is formed at a position concentric with the female thread portion of the front wall 60f.

[0030] The bolt 27 has a male threaded portion 27a which is the screw shaft, and a head 27b provided at the end of the male threaded portion 27a. The bolt 27 constitutes a contact member 27 in which its head 27b abuts against the rear surface of the support column 20. A reinforcing plate 20b fixed to the support column body 20a is provided at the portion of the support column 20 that the contact portion 27b abuts against. The reinforcing plate 20b is provided to prevent the rear wall of the support column 20 from being damaged by collision with the contact portion 27b of the contact member 27.

[0031] The contact member 27 moves axially toward the support column 20 by rotating relative to the female threaded nut 28 into which the male threaded portion 27a is screwed.

[0032] The contact member 27 forms an intervening portion 26 between the support column 20 and the arm-to-arm connecting member 60. By forming the intervening portion 26, the contact member 27 defines the minimum distance between the arm-to-arm connecting member 60 and the support column 20. In this embodiment, the intervening portion 26 is formed between the vicinity of the upper end portion 62 of the arm-to-arm connecting member 60 and the support column 20.

[0033] The intervening portion 26 is formed by the contact portion 27b of the contact member 27 and the portion of the male threaded portion 27a that is exposed from the arm-to-arm connecting member 60. By rotating the contact member 27 axially in either direction, the minimum value of the distance between the support column 20 and the arm-to-arm connecting member 60, which is the intervening dimension L of the intervening portion 26, can be adjusted.

[0034] As shown in Figure 2, the loading platform 70 is rotatably connected to the arm-to-arm connecting member 60. Specifically, the base end of the loading platform 70 is rotatably connected to the arm-to-arm connecting member 60 at a position lower than the connection portion of the arm-to-arm connecting member 60 with the second arm 50. The loading platform 70 is configured to rotate relative to the arm-to-arm connecting member 60 within a range from a vertical position (storage state) to a horizontal position (deployed state).

[0035] Therefore, as shown in Figure 2, the loading platform lifting device 10 is configured to bring the pair of left and right arm connecting members 60 and the loading platform 70 parallel to the pair of left and right support columns 20 when the cylinder 80 is retracted.

[0036] A locking lever 72 is attached to the side of the loading platform 70. As shown in Figure 2, the locking lever 72 engages with a locking lever receiver 22 attached to the support column 20, thereby locking the loading platform 70 in its retracted state and preventing it from being accidentally deployed.

[0037] Furthermore, as shown in Figure 4, a load-receiving platform support member 75 is installed between the side of the load-receiving platform 70 and the side of the arm-to-arm connecting member 60. Both ends of the load-receiving platform support member 75 are rotatably connected to the side of the load-receiving platform 70 and the side of the arm-to-arm connecting member 60, respectively. The middle section of the load-receiving platform support member 75 is bendable. As a result, when the load-receiving platform 70 is deployed and in a horizontal position, the load-receiving platform support member 75 prevents the load-receiving platform 70 from rotating any further and supports the load-receiving platform 70. When the load-receiving platform 70 is in the retracted position, the load-receiving platform support member 75 is bent in the middle section and positioned to overlap with the load-receiving platform 70.

[0038] As shown in Figure 2, the cylinder 80 is positioned inside the support column 20, extending in the height direction. The upper end 83 of the cylinder 80 is rotatably connected to the upper end of the support column 20 via a shaft member 84. The lower end 81 of the cylinder 80 is rotatably connected to approximately the middle of the first arm 40 via a shaft member 82. The cylinder 80 drives the first arm 40, thereby raising and lowering the load-receiving platform 70 while maintaining its orientation.

[0039] 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 column 20, is set higher than the position of the shaft member 42, which is the pivot center position on 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.

[0040] The power unit 90 supplies and discharges hydraulic fluid to the cylinder 80 via piping (not shown). The power unit 90 is located inside the cross member 30, as shown in Figure 2.

[0041] A bumper member 100 is installed between the lower ends of a pair of left and right support columns 20.

[0042] As shown in Figure 2, an inverted L-shaped reinforcing member 110 is joined so as to contact the portion of the support column 20 that extends downward from the loading platform 1 and the bottom surface of the loading platform 1 perpendicular to that portion. The reinforcing member 110 reinforces the joint between the support column 20 and the rear end of the loading platform 1.

[0043] An operation button 120 is provided on the side of the support column 20 for operating the loading platform 70 to raise or lower it. When the operation button 120 is operated, the power unit 90 is activated, and the power unit 90 raises or lowers the loading platform 70.

[0044] Next, the operation of the loading platform lifting device 10 will be explained. When loading work is performed on a truck vehicle, as shown in Figure 4, the loading platform 70 is unfolded to a horizontal position, and the cylinder 80 is extended to a ground position.

[0045] When performing a lifting operation, the worker places the load (not shown) onto the loading platform 70, and then operates the operation button 120 to retract the cylinder 80. As a result, the tip 43 of the first arm 40 rises together with the tip 53 of the second arm 50 and the inter-arm connecting member 60, and the loading platform 70 connected to the inter-arm connecting member 60 also rises to near the height of the floor surface 1a of the loading platform 1 while maintaining a horizontal position. This state is shown in Figure 5.

[0046] When unloading cargo from the loading platform 1, the loading platform lifting device 10 performs the reverse movement described above.

[0047] Next, the procedure for adjusting the highest position of the loading platform 70 will be explained with reference to Figure 5.

[0048] 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 raised position of the arm-to-arm connecting member 60 and the load-receiving platform 70 when the intervening dimension L (see Figure 3) of the intervening portion 26 of the load-receiving platform highest-raised 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 dashed lines, indicate the highest raised position of the arm-to-arm connecting member 60 and the load-receiving platform 70 when the intervening dimension L of the intervening portion 26 of the load-receiving platform highest-raised position adjustment means 25 is large.

[0049] The parallel link mechanism is configured such that the higher the load-receiving platform 70 is, the closer the inter-arm connecting member 60 is to the support column 20. Therefore, when the interposition dimension L of the interposition part 26 between the inter-arm connecting member 60 and the support column 20 is relatively small, the highest position of the load-receiving platform 70 is relatively high, as shown by the solid line in Figure 5. On the other hand, when the interposition dimension L of the interposition part 26 is relatively large, the highest position of the load-receiving platform 70 is relatively low, as shown by the dashed line in Figure 5.

[0050] Therefore, the highest position of the load-receiving platform 70 can be adjusted by adjusting the intervening dimension L of the intervening portion 26 interposed between the arm-to-arm connecting member 60 and the support column 20. Specifically, the highest position of the load-receiving platform 70 can be adjusted by axially rotating the contact member 27 in either direction.

[0051] <Effects and Effects> As described above, the load-receiving platform lifting device 10 according to this embodiment allows the maximum height of the load-receiving platform 70 to be adjusted by adjusting the intervening dimension L of the intervening part 26 interposed between the arm-to-arm connecting member 60 and the support column 20. Since both the intervening part 26 and the load-receiving platform 70 are located near the arm-to-arm connecting member 60, the operator can adjust the maximum height of the load-receiving platform 70 while simultaneously checking the intervening dimension L of the intervening part 26 and the height position of the load-receiving platform 70 within the same field of view. As a result, this adjustment work can be easily performed.

[0052] Furthermore, with the load-receiving platform lifting device 10, the intervening portion 26 of the load-receiving platform's highest position adjustment means 25 is configured to be formed between the vicinity of the upper end 62 of the arm-to-arm connecting member 60 and the support column 20. Therefore, compared to, for example, the case where the intervening portion 26 is formed between the vicinity of the lower end 61 of the arm-to-arm connecting member 60 and the support column 20, it is possible to suppress disturbances in the posture of the arm-to-arm connecting member 60 and the load-receiving platform 70 at the highest position.

[0053] This point will be explained in detail using Figure 6. As shown in Figure 6(a), even when the intervening portion 26 of the load-receiving platform's 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 column 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 connection portion between the first arm 40 and the inter-arm connecting member 60 (the shaft member 44 in Figure 2) is located relatively far from the intervening portion 26. The cylinder thrust is a vector directed towards 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 is applied to the inter-arm connecting member 60 that attempts to rotate it counterclockwise around the intervening portion 26 in the figure. Furthermore, since the cylinder 80 is connected to the first arm 40 at approximately the midpoint of the longitudinal direction of the first arm 40, the cylinder thrust causes a bending deformation in the first arm 40, causing it to curve upward and to the left in the figure. When bending deformation occurs in the first arm 40, the distance between the connection point between the first arm 40 and the support column 20 (shaft member 42 in Figure 2) and the connection point between the first arm 40 and the inter-arm connecting member 60 (shaft member 44 in Figure 2) decreases. As this distance decreases, the inter-arm connecting member 60 rotates counterclockwise around the intervening portion 26 in the figure. Thus, when the intervening portion 26 of the load-receiving platform's 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 column 20, the action of the force moment generated in the inter-arm connecting member 60 and the action of the bending deformation generated in the first arm 40 combine to cause the inter-arm connecting member 60 and the load-receiving platform 70 to become distorted in their posture, as shown in Figure 6(a), causing them to rotate counterclockwise in the figure.

[0054] On the other hand, as shown in Figure 6(b), when the intervening portion 26 of the load-receiving platform's highest position adjustment means 25 is formed between the vicinity of the upper end 62 of the arm-to-arm connecting member 60 and the support column 20, the connecting portion between the first arm 40 and the arm-to-arm connecting member 60 (the shaft member 44 in Figure 2) is located relatively close to the intervening portion 26. As a result, even if the cylinder thrust transmitted to the arm-to-arm connecting member 60 and directed towards the upper left of the figure generates a moment of force that attempts to rotate the arm-to-arm connecting member 60 clockwise around the intervening portion 26, the magnitude of this moment of force is smaller than the magnitude of the moment of force in the case of Figure 6(a), and the force acting on the second arm 50 is also small, so it is highly unlikely that the second arm 50 will deform and the arm-to-arm connecting member 60 will rotate clockwise. Furthermore, when the intervening portion 26 is formed between the vicinity of the upper end 62 of the arm-to-arm connecting member 60 and the support column 20, the first arm 40 is also unlikely to bend or deform due to the cylinder thrust. Therefore, when the intervening portion 26 of the load-receiving platform's 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 column 20, the disruption of the posture of the inter-arm connecting member 60 and the load-receiving platform 70 so as to rotate clockwise in the figure is suppressed.

[0055] Furthermore, with the loading platform lifting device 10, the highest position of the loading platform 70 can be adjusted simply by rotating the contact member 27 in either direction, making the adjustment work easy.

[0056] Furthermore, with the loading platform lifting device 10, by tightening the fixing nut 29 toward the arm connecting member 60, it is possible to prevent the contact member 27 from rotating due to vibrations during the movement of the truck vehicle, thereby preventing the intervening dimension L of the intervening part 26 from unintentionally increasing or decreasing.

[0057] (modified version) In the above-described load-receiving platform lifting device 10, the female thread portion into which the male thread portion 27a of the contact member bolt 27 is screwed is formed by a female thread nut 28 fixed to the front side wall 60f of the arm-to-arm connecting member 60. However, the female thread portion 60fhA may be formed in the through hole 60fh of the arm-to-arm connecting member 60 without providing the female thread nut 28 (see Figure 7).

[0058] Furthermore, in the above-described loading platform lifting device 10, the head 27b (contact portion 27b) of the bolt 27, which is a contact member, was described as contacting a reinforcing plate 20b fixed to the rear surface of the support column body 20a. However, as shown in Figure 7, the head 27b of the bolt 27 may be made to contact the rear surface of the support column body 20a directly without providing a reinforcing plate 20b to the rear surface of the support column body 20a.

[0059] Furthermore, although the above-described loading platform lifting device 10 was explained assuming that the loading platform's highest position adjustment means 25 is provided on the arm-to-arm connecting member 60 side, the loading platform's highest position adjustment means 25 may also be provided on the support column 20 side. That is, the loading platform's highest position adjustment means 25 may be configured such that the male threaded portion 27a of the contact member bolt 27 is screwed to the support column 20 side, and the head 27b abuts against the front surface of the front wall 60f of the arm-to-arm connecting member 60.

[0060] Furthermore, although the lower end 81 of the cylinder 80 of the load receiving platform lifting device 10 described above was described as being rotatably connected to the first arm 40, it may also be rotatably connected to the second arm 50. [Industrial applicability]

[0061] The present invention can be applied, for example, to a loading platform lifting device. [Explanation of Symbols]

[0062] 1. Cargo bed 10 Loading platform lifting device 20. Support posts (support members) 25. Means for adjusting the highest position of the loading platform 26 Interposition part 27 Contact members (bolts) 27a Male threaded portion 27b Contact area (bolt head) 29 Fixing nuts 40 First Arm 41 Base end of the first arm 43 Tip of the first arm 50 Second Arm 51 Base end of the second arm 53 Tip of the second arm 60 Inter-arm connecting member 70 Loading platform 80 cylinders 81 Lower end of cylinder 83 Cylinder tip

Claims

1. 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 are positioned lower than the first arm and their base ends are rotatably connected to the support member, A pair of left and right arm connecting members are rotatably connected to the tip end of the first arm and rotatably connected to the tip end of the second arm at a position lower than the connection position with the first arm, A load-receiving platform rotatably connected to the arm-to-arm connecting member, A cylinder for raising and lowering the aforementioned loading platform, Equipped with, In a load-receiving platform lifting device in which the support member, the first arm, the second arm, and the inter-arm connecting member constitute a parallel link mechanism, and the cylinder drives the first arm or the second arm, thereby enabling the load-receiving platform to be raised and lowered while maintaining its orientation, The support members are a pair of left and right support columns erected on both sides of the rear end of the cargo bed of the vehicle. The parallel link mechanism is configured such that the higher the load-receiving platform, the closer the arm-to-arm connecting member is to the support column. The load receiving platform's highest position adjustment means is further provided, which is interposed between the arm-to-arm connecting member and the support column to form an intervening portion that defines the minimum distance between the arm-to-arm connecting member and the support column, and whose intervening dimensions are adjustable so as to allow adjustment of the minimum value. A loading platform lifting device characterized by the following features.

2. A loading platform lifting device according to claim 1, The cylinder is rotatably connected at one end to the support column and rotatably connected at the other end to the first arm. The load receiving platform's highest position adjustment means is configured such that the intervening portion is formed between the vicinity of the upper end of the arm-to-arm connecting member and the support column. A loading platform lifting device characterized by the following features.

3. A loading platform lifting device according to claim 1 or claim 2, The loading platform lifting device is characterized in that the means for adjusting the highest position of the loading platform includes a contact member having a male screw portion screwed to the other of the support column and the arm connecting member so as to be movable toward one of the support column and the arm connecting member, and a contact portion that contacts the one of the support column and the arm connecting member.

4. A loading platform lifting device according to claim 3, The loading platform lifting device is characterized in that the means for adjusting the highest position of the loading platform further includes a nut screwed onto the male threaded portion.

Images