Loading platform lifting device

Abstract

The torsion bar mounting angle can be flexibly adjusted with a simple configuration. [Solution] A loading platform lifting device for raising and lowering a loading platform relative to a vehicle is provided, comprising: a bracket that rotatably supports the loading platform; a torsion bar that biases the loading platform in an upright direction relative to the bracket; a holder that holds one end of the torsion bar; and a key that is attached to the bracket and contacts the holder to restrict the rotation of the holder, wherein the key has at least one contact surface that contacts the holder, and the contact surface is configured to be changeable.

Description

Technical Field

[0001] The present invention relates to a load platform lifting device mounted on a vehicle.

Background Art

[0002] A load platform lifting device is a device that raises and lowers a load platform between the height of the floor of the vehicle's load platform and the ground to assist in loading and unloading operations, that is, the operation of loading and unloading goods onto the load platform. Some of this type of load platform lifting device stand the load platform vertically during vehicle travel and use it in a horizontal loading and unloading posture during loading and unloading operations. Although the posture change of this loading and unloading platform is generally performed manually, since the load platform is a heavy object, the load platform lifting device may be provided with a mechanism that uses the torsional restoring force of a torsion bar to assist the operator in changing the posture of the load platform.

[0003] In order to obtain an appropriate assisting force during the posture change operation of the load platform, it is necessary for the attachment angle of the torsion bar, that is, the torsion angle, to be appropriate. On the other hand, a load platform lifting device equipped with an adjustment mechanism for the attachment angle of the torsion bar is known (Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the load platform lifting device of Patent Document 1, the above-described assisting force is adjusted by adjusting the relative angle between a holder that holds one end of the torsion bar and a bracket that rotatably supports the load platform. Specifically, a plurality of bolt holes are provided in the bracket, and by changing the bolt hole for fixing the holder, the attachment angle of the holder to the bracket, that is, the torsion angle of the torsion bar, is changed.

[0006] However, this configuration requires a number of bolt holes corresponding to the number of selectable holder mounting angles. If the holder mounting angles are further multi-staged, the bracket may become larger or its structure more complex as the number of bolt holes increases.

[0007] The present invention aims to provide a loading platform lifting device that allows for flexible adjustment of the mounting angle of the torsion bar with a simple configuration. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a loading platform lifting device for raising and lowering a loading platform relative to a vehicle, comprising: a bracket that rotatably supports the loading platform; a torsion bar that biases the loading platform in an upright direction relative to the bracket; a holder that holds one end of the torsion bar; and a key that is attached to the bracket and contacts the holder to restrict the rotation of the holder, wherein the key has at least one contact surface that contacts the holder, and the contact surface is configured to be changeable. [Effects of the Invention]

[0009] According to the present invention, the mounting angle of the torsion bar can be flexibly adjusted with a simple configuration. [Brief explanation of the drawing]

[0010] [Figure 1] Rear left side view of a vehicle equipped with a loading platform lifting device according to one embodiment of the present invention [Figure 2] Left side view of the loading platform lifting device. [Figure 3] Rear view of the loading platform lifting device. [Figure 4] Plan view of the loading platform lifting device [Figure 5] This diagram corresponds to Figure 2 and shows the loading platform in a raised state. [Figure 6] Schematic diagram showing the wire path [Figure 7] Perspective view showing the main part of the biasing mechanism provided in the load receiving platform lifting device as seen from the outside in the left - right direction of the load receiving platform [Figure 8] Perspective view showing the main part of the biasing mechanism provided in the load receiving platform lifting device as seen from the center side in the left - right direction of the load receiving platform [Figure 9] Exploded view showing the mechanism shown in FIG. 7 with the load receiving platform omitted [Figure 10] Exploded view showing the mechanism shown in FIG. 8 with the load receiving platform omitted [Figure 11] Figure showing the shape of the key [Figure 12] Figure showing the change in the mounting angle of the holder depending on the mounting method of the key [Figure 13] Figure showing the removal procedure of the torsion bar [Figure 14] Figure showing the removal procedure of the torsion bar [Figure 15] Figure showing the removal procedure of the torsion bar [Figure 16] Figure showing the removal procedure of the torsion bar [Figure 17] Figure showing the removal procedure of the torsion bar [Figure 18] Figure showing the removal procedure of the torsion bar [Figure 19] Figure showing a modified example of the auxiliary force adjusting mechanism [Figure 20] Figure showing an example of the mounting structure of the torsion bar

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] 1. Load receiving platform lifting device FIG. 1 is a left - side view of the rear part of a vehicle equipped with a load receiving platform lifting device according to an embodiment of the present invention. In this specification, the direction corresponding to the left side in FIG. 1 is defined as the front of the load receiving platform lifting device, and the direction corresponding to the right side in FIG. 1 is defined as the rear of the load receiving platform lifting device.

[0013] The vehicle shown in Figure 1 is equipped with a driver's cab (not shown) located at the front of the chassis frame (vehicle frame) 101, a cargo bed 103 mounted on the chassis frame 101, and a cargo bed lifting device 100 mounted on the rear of the cargo bed 103.

[0014] Figure 2 is a left side view of the loading platform lifting device, Figure 3 is a rear view, Figure 4 is a top view, and Figure 5 is a diagram corresponding to Figure 2, showing the loading platform in the raised position. Figures 2-5 show the interior in perspective. However, the loading platform 40 is omitted from Figures 3 and 4 to avoid clutter. Also, the internal components of posts 10L and 10R are omitted from Figure 4.

[0015] The loading platform lifting device 100 of this embodiment is a device for raising and lowering a loading platform 40 relative to a vehicle, and comprises left and right posts 10L, 10R, left and right sub-posts 20L, 20R, left and right sliders 30L, 30R, loading platform 40, cross member 50, hydraulic cylinder 60, power unit 70, pulleys 80La, 80Lb, 80Ra-80Rc, 81L, 81R, and wires 90L, 91L, 90R, 91R. Each element will be described in order below.

[0016] 2. Post Posts 10L and 10R are located at both the left and right ends of the rear end of the vehicle's cargo bed 103 and extend vertically. Hollow pipes, such as square pipes, are used for posts 10L and 10R. The front space inside posts 10L and 10R is called the front chamber 12, and the rear space is called the rear chamber 13. The front chamber 12 and the rear chamber 13 may be separated by a bulkhead (not shown), but they do not have to be clearly separated. A vertically extending slit 14 (see Figure 3) is provided in the rear wall of the rear chamber 13. In addition, a wire fixing section 15 (Figure 2) is provided near the lower end inside posts 10L and 10R.

[0017] 3. Subposts Subposts 20L and 20R are inserted into the rear chamber 13 of posts 10L and 10R so as to be movable in the vertical direction. Slits 21 are formed vertically on the rear wall of subposts 20L and 20R so as to correspond to the slits 14 of posts 10L and 10R. These subposts 20L and 20R are provided with rollers 22 (Figure 2) that roll along the rear inner wall of the rear chamber 13, and are configured to move smoothly up and down inside the rear chamber 13 guided by these rollers 22. Although not shown, guide rollers are provided at the bottom of the front chamber 12 of posts 10L and 10R, and the vertical sliding movement of subposts 20L and 20R is also guided by these guide rollers. A wire fixing portion 23 (Figure 2) is provided protruding forward near the lower end of subposts 20L and 20R. Furthermore, brackets 24 (Figure 2) for attaching pulleys 81L and 81R are provided on the upper portion of subposts 20L and 20R, protruding to the vestibule 12.

[0018] 4. Slider Sliders 30L and 30R extend vertically and are inserted into subposts 20L and 20R, respectively, and move up and down inside the subposts 20L and 20R. Rollers 31 are provided on these sliders 30L and 30R at intermediate vertical positions and near the upper ends. These rollers 31 roll on the inner walls of the subposts 20L and 20R when the sliders 30L and 30R are raised and lowered. The horizontal cross-section of the sliders 30L and 30R is shaped to extend front to back, and the rear part protrudes behind the posts 10L and 10R through the slits 21 in the subposts 20L and 20R and the slits 14 in the posts 10L and 10R. Brackets 32 are provided at the lower part of these protruding portions. In addition, the sliders 30L and 30R are provided with wire fixing parts 33 (Figure 2) for fixing the ends of the wires 90L and 90R, positioned, for example, between the upper and lower rollers 31.

[0019] 5. Loading platform The loading platform 40 is rotatably connected to the brackets 32 of the sliders 30L and 30R via pins 41 (Figure 2), and moves up and down in accordance with the vertical movement of the sliders 30L and 30R. When not in use, the loading platform 40 is raised to a vertical driving position to form the rear wall (tailgate) of the cargo bed 103 (see Figure 1). On the other hand, during cargo handling operations, the loading platform 40 is lowered to a horizontal loading position and moves up and down between the height of the floor of the cargo bed 103 and the ground level with cargo placed on it (see Figures 2 and 5). As shown in Figure 1, the loading platform lifting device 100 is equipped with a locking mechanism 43 that locks the loading platform 40 in an upright position (driving position) when the vehicle is in motion. The locking mechanism 43 is a mechanism such as a latch or bolt, but its configuration is not particularly limited as long as it can hold the loading platform 40 in place so that it does not fall over when the vehicle is in motion.

[0020] 6. Cross member The cross member 50 extends to the left and right, connecting the intermediate vertical portions of the posts 10L and 10R. The cross member 50 is hollow, and its internal space communicates with the internal space of the posts 10L and 10R. When the loading platform lifting device 100 is mounted on a vehicle, the cross member 50 is located above the vehicle's chassis frame 101. Although not specifically shown in the figures, the rear surface of the cross member 50 is a removable cover. The cross member 50 is also provided with wire fixing parts 51 and 52 for fixing the ends of the wires 90L and 90R, respectively.

[0021] 7. Hydraulic Cylinder The hydraulic cylinder 60 is housed within the cross member 50. The hydraulic cylinder 60 can also be installed with its rod facing left, but in this embodiment, it is installed with its rod facing right, and the tube is fixed to the inner wall of the cross member 50 via a support member. The tip of the rod of the hydraulic cylinder 60 reciprocates within the central region of the cross member 50 in the left-right direction as the hydraulic cylinder 60 extends and retracts.

[0022] 8. Power plant The power unit 70 is a single unit that drives the hydraulic cylinder 60. A detailed explanation is omitted, but it includes a hydraulic pump, an electric motor, a tank, a contactor, a valve unit, etc. The electric motor drives the hydraulic pump, and the valve unit controls the direction and flow rate of the pressurized oil, supplying pressurized oil from the tank to the hydraulic cylinder 60. The return oil from the hydraulic cylinder 60 returns to the tank. In this embodiment, the power unit 70 is housed within the cross member 50 and is located on one side of the hydraulic cylinder 60 in the left-right direction (the right side in this embodiment), and is arranged side by side with the hydraulic cylinder 60. In this embodiment, as shown in Figures 3 and 4, the power unit 70 is located on the extension of the central axis of the rod of the hydraulic cylinder 60.

[0023] 9. Pulley Pulleys 80La and 80Lb guide wire 90L, pulley 81L guides wire 91L, pulley 80Ra-80Rc guides wire 90R, and pulley 81R guides wire 91R (as described later). It is preferable to use pulleys 80La, 80Lb, 81L and pulleys 80Ra-80Rc, 81R with a large diameter, as long as they do not interfere with other structures. This is because the curvature of the turning portion of wires 90L, 90R, 91L, and 91R is suppressed, and a longer lifespan for wires 90L, 90R, 91L, and 91R can be expected.

[0024] Pulleys 80La, 80Ra, and 80Rb are fixed pulleys housed in the cross member 50 (hereinafter, these three pulleys will be referred to as "fixed pulleys" as appropriate). Fixed pulleys 80La, 80Ra, and 80Rb have their rotation axes extending forward and backward. Of these, fixed pulleys 80La and 80Rb are located near the left end of the cross member 50 and are attached to the tube of the hydraulic cylinder 60 (or the inner wall surface of the cross member 50) via brackets, with a portion of each facing the front chamber 12 of post 10L. On the other hand, fixed pulley 80Ra is located near the right end of the cross member 50 and is attached to the inner wall surface of the cross member 50 via brackets, with a portion of each facing the front chamber 12 of post 10R.

[0025] Pulleys 80Lb, 80Rc, 81L, and 81R are movable pulleys (hereinafter, these four pulleys will be referred to as "movable pulleys" as appropriate). Of these, movable pulleys 80Lb and 80Rc are attached to the rod end of the hydraulic cylinder 60 via brackets in a position where their rotation axis is extended forward and backward. These movable pulleys 80Lb and 80Rc reciprocate horizontally in the central region of the cross member 50 in the left-right direction as the hydraulic cylinder 60 extends and retracts. On the other hand, movable pulleys 81L and 81R are attached to the brackets 24 of subposts 20L and 20R in a position where their rotation axis is extended left and right, and are positioned across the front chamber 12 and rear chamber 13 of posts 10L and 10R. These movable pulleys 81L and 81R reciprocate vertically inside posts 10L and 10R as the subposts 20L and 20R are raised and lowered.

[0026] 10. Wire Figure 6 is a schematic diagram showing the wire path. In this figure, components that have already been explained are given the same reference numerals as in the previously shown drawings, and their explanations are omitted.

[0027] As shown in Figure 6, wires 90L and 90R (see solid lines in the figure) are attached to movable pulleys 80Lb and 80Rc, respectively. One end is fixed to the stationary structure, the cross member 50, and the other end is secured to the wire fixing portion 23 of the left and right subposts 20L and 20R, respectively. Specifically, wire 90L is attached to the movable pulley 80Lb and the fixed pulley 80La, with one end secured to the wire fixing portion 51, and fixed to the cross member 50 via the wire fixing portion 51. This wire 90L extends to the right from the wire fixing portion 51, turns its path to the left via the movable pulley 80Lb, then turns downward via the fixed pulley 80La, and finally its other end is secured to the wire fixing portion 23 of the subpost 20L. One wire 90R is connected to the movable pulley 80Rc and the fixed pulleys 80Rb and Ra, with one end secured to the wire fixing part 52 and fixed to the cross member 50 via the wire fixing part 52. This wire 90R extends to the right from the wire fixing part 52, turns back to the left via the movable pulley 80Rc, then turns back to the right again via the fixed pulley 80Rb, and then turns downward via the fixed pulley 80Ra, and finally its other end is secured to the wire fixing part 23 of the subpost 20R. The subposts 20L and 20R are suspended in this manner by the wires 90L and 90R, respectively.

[0028] Wires 91L and 91R (see dashed lines in the figure) are each attached to movable pulleys 81L and 81R, with one end fixed to the stationary structures posts 10L and 10R, and the other end secured to sliders 30L and 30R, respectively. Specifically, wire 91L is attached to movable pulley 81L, with one end secured to post 10L via the wire fixing part 15. This wire 91L extends upward from the wire fixing part 15, folds back downward via movable pulley 81L, and finally its other end is secured to the wire fixing part 33 of slider 30L. On the other hand, wire 91R is attached to movable pulley 81R, with one end secured to post 10R via the wire fixing part 15. The wire 91R extends upward from the wire fixing part 15, folds back downward via the movable pulley 81R, and finally its other end is secured to the wire fixing part 33 of the slider 30R. The sliders 30L, 30R and the load receiving platform 40 are thus suspended by the wires 91L, 91R.

[0029] 11. Operation When using the loading platform lifting device 100, first, the lock mechanism 43 of the loading platform 40, which is in an upright traveling position as shown in Figure 1, is released, and the loading platform 40 is lowered to a horizontal loading / unloading position as shown in Figure 5. For example, when unloading cargo from the loading platform 103, the cargo from the loading platform 103 is transferred to the loading platform 40 while the loading platform 40 is at the same height as the floor of the loading platform 103. Then, the hydraulic cylinder 60 is retracted by operating the operating device (not shown) as appropriate. When the hydraulic cylinder 60 is retracted, the movable pulleys 80Lb and 80Rc move toward the fixed pulleys 80La and 80Rb, the wires 90L and 90R loosen, the subposts 20L and 20R descend, and consequently the movable pulleys 81L and 81R descend. As the movable pulleys 81L and 81R descend, the wires 91L and 91R loosen, and the load receiving platform 40 descends together with the sliders 30L and 30R.

[0030] Conversely, when loading cargo onto the loading platform 103, the cargo is placed on the loading platform 40 while it is at ground level, and the hydraulic cylinder 60 is extended by operating the control device (not shown) as appropriate. When the hydraulic cylinder 60 is extended, the movable pulleys 80Lb and 80Rc move away from the fixed pulleys 80La and 80Rb, and the subposts 20L and 20R are lifted by the wires 90L and 90R, causing the movable pulleys 81L and 81R to rise accordingly. When the movable pulleys 81L and 81R rise, the loading platform 40 is lifted and raised by the wires 91L and 91R along with the sliders 30L and 30R. If the cargo handling operation is to continue, the above operations are repeated, and when the operation is completed, the loading platform 40 is raised to the traveling position as shown in Figure 1 and the loading platform 40 is locked by the locking mechanism 43.

[0031] 12.Biasing mechanism The loading platform lifting device 100 raises the loading platform 40 vertically to the driving position (Figure 1) when the vehicle is in motion, and lowers the loading platform 40 to the horizontal loading position (Figure 5) when loading and unloading work. Since the change in the position of the loading platform 40 is done manually, the loading platform lifting device 100 is equipped with a mechanism that uses the torsional return force (restoring force) of the torsion bar to assist the worker in changing the position of the loading platform 40.

[0032] Figure 7 is a perspective view showing the main part of the biasing mechanism as seen from the outside in the left-right direction of the loading platform 40, Figure 8 is a perspective view showing it as seen from the center in the left-right direction, and Figures 9 and 10 are exploded views showing the mechanism shown in Figures 7 and 8, with the loading platform 40 omitted from the illustration. As shown in Figures 7-9, the loading platform lifting device 100 has a biasing mechanism which includes a torsion bar 200 that biases the loading platform 40 in the upright direction relative to the bracket 32 ​​of the slider 30L, and a holder 210 that is supported by the bracket 32 ​​of the slider 30L and holds one end of the torsion bar 200.

[0033] In this embodiment, two torsion bars 200 are provided side by side, but the number of torsion bars 200 is not limited; there may be one, or there may be three or more. Also, Figures 7 and 8 illustrate a configuration in which the torsion bar 200 is restrained to the bracket 32 ​​of the left slider 30L via a holder 210, but the torsion bar 200 may also be restrained to the bracket 32 ​​of the right slider 30R, or there may be a configuration in which a torsion bar 200 restrained to the bracket 32 ​​of slider 30L and a torsion bar 200 restrained to the bracket 32 ​​of slider 30R are provided (Figure 20).

[0034] In this embodiment, the torsion bar 200 has a shape in which both ends are bent (Figure 17). One end of the torsion bar 200 is inserted into and restrained by the holder 210, and the other end is inserted into and restrained by the holder 310 (Figure 20). The holder 310 that restrains the other end of the torsion bar 200 is located at the front of the underside of the loading platform 40 (at the bottom in Figure 7, as the loading platform 40 is upright) and is provided inside the cross member 42 that extends to the left and right. In this way, one end of the torsion bar 200 is restrained by the holder 210 fixed to the bracket 32, and the other end is restrained by the holder 310 which rotates together with the loading platform 40 relative to the bracket 32. As a result, when the loading platform 40 is tilted to a horizontal loading position, it twists, generating a torsional return force that acts in the direction of raising the loading platform 40 upright. This torsional return force is set to be weaker than the force that causes the loading platform 40 to tip over due to gravity, and serves as an assisting force when workers manually raise the loading platform 40 to a driving position.

[0035] In this embodiment, the holder 210 comprises a first part 211 that holds one end of the torsion bar 200 and a second part 212 that sandwiches the bracket 32 ​​between the first part 211 and the second part 212.

[0036] The first component 211 is located between the bracket 32 ​​and the loading platform 40 and has a mounting portion 213 for attachment to the bracket 32 ​​and a holding portion 214 having a holding chamber 215 that opens opposite the corresponding torsion bar 200. The mounting portion 213 has an elongated hole 218 along the rotational direction of the loading platform 40 and is supported by bolts B4 passed through the elongated hole 218 and the bolt holes 32a of the bracket 32, on the side of the bracket 32 ​​facing inward in the left-right direction (vehicle width direction). The number of holding chambers 215 provided in the holding portion 214 corresponds to the number of torsion bars 200 to be held (one in this embodiment), and each accommodates one end of the corresponding torsion bar 200. If it is necessary to restrict the left-right movement of the torsion bar 200, a retaining pin (not shown) can be inserted into a hole 216 provided in the holding chamber 215 so that the bent end of the torsion bar 200 interferes with the retaining pin. The holding chambers 215 are provided in the first part 211 in the same number as the number of torsion bars 200 held by the holder 210 (two in this embodiment).

[0037] Furthermore, the holder 210 has the pin 41, which not only holds the torsion bar 200 but also serves to rotatably connect the load receiving platform 40 to the bracket 32. The pin 41 may be provided on either the first part 211 or the second part 212, but in this embodiment it is provided on the second part 212 and can be inserted into and removed from the pin hole 32p provided in the bracket 32 ​​from the outside in the left-right direction (vehicle width direction). In this embodiment, the pin 41 and the pin hole 32p are located on the extension of the torsion bar 200 (they are in a positional relationship that overlaps with the extension line).

[0038] The second part 212 has a mounting portion 217 for the bracket in addition to the pin 41. The mounting portion 217 is a non-circular (square in this embodiment) plate when viewed in the direction of the center line of the pin 41, and has an elongated hole 219 that is aligned with the rotational direction of the loading platform 40. It is held in place from the outside in the left-right direction (vehicle width direction) by the retaining plate 220, and is supported by bolts B3 that pass through the elongated hole 219 and the bolt holes 32b of the bracket 32, on the surface of the bracket 32 ​​that faces outward in the left-right direction (vehicle width direction).

[0039] Furthermore, in this embodiment, the first part 211 and the second part 212 are locked together so as not to rotate. Specifically, the tip of the pin 41 of the second part 212 has a notch 41a, which makes it non-circular. The mounting portion 213 of the first part 211 is provided with an insertion hole 213a (Figure 9) which is non-circular in shape to correspond to the tip of the pin 41, and the first part 211 and the second part 212 are locked together so as not to rotate when the non-circular tip of the pin 41 is inserted into the insertion hole 213a. In this embodiment, the holding portion 214 of the first part 211 is tilted by a predetermined angle (for example, 10 degrees) in the rotational direction of the loading platform 40 relative to the mounting portion 217 of the second part 212, but this tilt angle can be changed and does not necessarily need to be tilted.

[0040] 13.Auxiliary force adjustment mechanism In order to obtain appropriate assistance force during the operation of changing the posture of the loading platform 40 (the operation of raising the loading platform 40), the mounting angle of the torsion bar 200, that is, the twist angle applied to the torsion bar 200 when it is tilted in the loading position, must be appropriate. Therefore, the loading platform lifting device 100 is equipped with an assistance force adjustment mechanism 230 that adjusts the mounting angle of the torsion bar 200 and adjusts the assistance force.

[0041] The auxiliary force adjustment mechanism 230 is equipped with a key 231 that is attached to the bracket 32 ​​and contacts (surface contact in this embodiment) the holder 210 to restrict the rotation of the holder 210. Specifically, the key 231 contacts the outer peripheral surface of the holder 210 that faces radially outward from the pin 41, thereby restricting the rotation of the holder 210. The key 231 may contact either the first component 211 or the second component 212, but in this embodiment, it contacts the smooth outer peripheral surface of the mounting portion 217 of the second component 212.

[0042] The key 231 has a structure having at least one contact surface that contacts the holder 210, and in this embodiment it has two contact surfaces S1 and S2, and the contact surface with respect to the holder 210 can be changed, and the mounting angle of the holder 210 with respect to the bracket 32 ​​can be adjusted by reversing the front and back sides or changing the contact surface that contacts the holder 210 and reattaching it to the bracket 32, as defined by the contact surfaces. In this embodiment the front and back surfaces of the key 231 (two surfaces facing the center line direction of the pin 41) are parallel to each other and have a non-regular polygonal shape (trapezoidal in this embodiment).

[0043] Specifically, the key 231 and the bracket 32 ​​are engaged at least at one connection point, and the connection point is formed or arranged in a line-symmetric or rotationally symmetrical manner. In this embodiment, the key 231 is provided with two circular through holes H, and the bracket 32 ​​is provided with two bolt holes 32c. In this embodiment, the two bolt holes 32c are arranged front to back. The key 231 is held in place from the outside in the left-right direction (vehicle width direction) by the retaining plate 220 together with the mounting portion 217 of the holder 210, and is fixed to the bracket 32 ​​by two bolts B passed through the through holes H and bolt holes 32c. In this embodiment, each pair of through holes H and bolt holes 32c constitute two connection points of the same shape. The two identically shaped connection points are arranged in a line-symmetric and rotationally symmetric configuration. The key 231, which is fixed to the bracket 32 ​​at these connection points, can be attached to the bracket 32 ​​either by flipping it over or by rotating it 180 degrees without flipping it over.

[0044] Figure 11 shows the mounting state of the key 231 as viewed from the outside (left side) in the vehicle width direction along the central axis of the pin 41, and Figure 12 shows the change in the mounting angle of the holder 210 depending on how the key 231 is mounted. As shown in Figure 11, of the contact surfaces S1 and S of the key 231, the contact surface S2 is not perpendicular and not parallel to the axis of symmetry C1 and C2 of the two through holes H that form the connection part, and is inclined with respect to the axis of symmetry C1 and C2 on the plane containing the axis of symmetry C1 and C2. Therefore, for example, if the key 231 is flipped over (reversed front to back) along the axis of symmetry C2, the angle to the ground θ (angle in the direction of rotation of the loading platform 40 with respect to the horizontal plane in Figure 11) changes. In the example in Figure 11, as shown in Figures 11(a) and 11(b), the angle to the ground θ of the contact surface S2 changes to one of two predetermined angles (in this example, +5° and -5°). For example, if the method of attaching the key 231 to the bracket 32 ​​is changed from the one shown in Figure 11(a) to the one shown in Figure 11(b), then, as shown in Figures 12(a) and 12(b), in this embodiment, the inclination (=θ) of the loading platform 40 in the rotational direction with respect to the vertical line of the mounting portion 217 of the second part 212 changes from +5 degrees to -5 degrees, and the inclination α of the holding portion 214 of the first part 211 with respect to the vertical line (angle in the rotational direction of the loading platform 40) changes from 15 degrees to 5 degrees.

[0045] Furthermore, the key 231 has a first contact surface S1 and a second contact surface S2 that are not parallel to each other, and by inverting it (upside down) along the axis of symmetry C1 of the two through holes H that form the connection portion and attaching it to the bracket 32, the first contact surface S1 or the second contact surface S2 can selectively contact the holder 210. Assuming that the contact surface located on the lower side in Figure 11 contacts the holder 210, as shown in Figures 11(a) and 11(c), the angle θ to the ground is different between the second contact surface S2 that contacts the holder 210 and the first contact surface S1 that contacts the holder 210. In this embodiment, an example is shown where the contact surface S1 is parallel to the axis of symmetry C1, and Figure 11(c) illustrates the case where the angle θ to the ground is 0 degrees. For example, if the mounting method of the key 231 is changed from the state shown in Figure 11(a) to the state shown in Figure 11(c), then, as shown in Figures 12(a) and 12(c), in this embodiment, the inclination (=θ) of the mounting portion 217 of the second part 212 with respect to the vertical changes from +5 degrees to 0 degrees, and the inclination α of the holding portion 214 of the first part 211 with respect to the vertical changes from 15 degrees to 10 degrees.

[0046] Furthermore, in this embodiment, the key 231 can be attached to the bracket 32 ​​by rotating it around the rotational symmetry axis C3 of the two through holes H that form the connection point, without having to reverse its orientation, so that the first contact surface S1 or the second contact surface S2 can selectively contact the holder 210. In other words, the mounting state shown in Figures 11(a) and 11(c) can also be changed by rotating the key 231 around the rotational symmetry axis C3. As mentioned above, if the mounting method of the key 231 is changed from the state shown in Figure 11(a) to the state shown in Figure 11(c), the inclination α of the holding portion 214 of the first part 211 with respect to the vertical changes from 15 degrees to 10 degrees.

[0047] As explained in Figures 11 and 12, by changing the mounting angle of the holder 210 to the bracket 32 ​​and adjusting the angle α of the holding part 214, the twist angle of the torsion bar 200 when the loading platform 40 is tilted into the loading position, and consequently the holding force when raising the loading platform 40, can be adjusted in three stages.

[0048] In this embodiment, the connection portion (through hole H and bolt hole 32c) is exemplified as being arranged in a line-symmetric or rotationally symmetrical manner. However, functionality may be ensured by the shape rather than the arrangement of the connection portion. For example, when a fitting structure is adopted between the holder 210 and the bracket 32 ​​to constitute the connection portion, such as a combination of a fitting structure and a bolt fastening its center, the fitting structure can be made line-symmetrical or rotationally symmetrical to realize a structure in which the key 231 can be reversed or rotated and reattached to the bracket 32.

[0049] 14. Torsion bar replacement mechanism Furthermore, since the torsion bar 200 needs to be replaced as it deteriorates or gets damaged, the loading platform lifting device 100 is equipped with a torsion bar replacement mechanism. The torsion bar replacement mechanism takes into account the insertion and removal of the torsion bar 200 from the cross member 42 of the loading platform 40 via the pin hole 32p from which the pin 41 has been removed, and has a fixing part 240 on the bracket 32 ​​for fixing the loading platform 40. The fixing part 240 is different from the pin 41 that connects the bracket 32 ​​and the loading platform 40, and is intended to maintain the state in which the loading platform 40 is held in place by the bracket 32 ​​so that the loading platform 40 does not sink even if the pin 41 is removed, and is located in a different position from the pin hole 32p into which the pin 41 is inserted. The fixing part 240 is also provided separately from a locking mechanism 43 which is responsible for locking the loading platform 40 in an upright driving position when the vehicle is in motion.

[0050] In this embodiment, the fixing portion 240 is a hole through which a fixing device passes. In this embodiment, fixing bolts are used as the fixing device, but fixing pins without threads can also be used as the fixing device. Although not shown, the side surface of the loading platform 40 is provided with bolt holes for screwing in fixing bolts or pin holes for inserting fixing pins. These bolt holes or pin holes are positioned to align with the fixing portion 240 when the loading platform 40 is in an upright traveling position. When a fixing pin is provided in the fixing device, it is preferable to set the dimensional tolerance between the fixing portion 240 and the pin hole through which the fixing pin passes and the fixing pin to be small enough so as not to hinder the insertion and removal of the fixing pin, and to minimize the displacement between the pin hole in the loading platform 40 (the hole through which the pin 41 passes) and the pin hole 32p of the bracket 32 ​​due to the sinking of the loading platform 40 when the pin 41 is removed.

[0051] For the fixing bolts, for example, bolts B, B3, or B4 can be used, but a configuration using bolts with a larger nominal diameter than these is also possible. In this case, a bolt storage section (bolt hole) for mounting the fixing bolts (not shown) may be provided separately from the fixing section 240 (for example, on the load receiving platform 40).

[0052] The fixing portion 240 is located on the outer surface of the bracket 32 ​​in the left-right direction (vehicle width direction), above the bolt hole 32c for attaching the key 231 and the pin hole 32p for inserting the pin 41, and is configured (arranged) to fix the loading platform 40 to the bracket 32 ​​in an upright driving position. However, the arrangement of the fixing portion 240 is not limited; for example, if there is sufficient space, it may be located behind the bolt hole 32c and pin hole 32p (configuration to hold the loading platform 40 in a loading / unloading position). The fixing portion 240 may also be provided on the inner surface of the bracket 32 ​​in the left-right direction (vehicle width direction).

[0053] 15. Procedure for adjusting the auxiliary force To adjust the auxiliary force provided by the torsion bar 200, first remove bolts B and B3, the retaining plate 220 and key 231, loosen bolt B4, and if necessary, attach bolt B to the fixing part 240 to secure the load-receiving platform 40 to the bracket 32.

[0054] Afterward, the holder 210 is rotated in the direction of rotation of the loading platform 40 to adjust the angle of the holder 210, and the contact surface is changed from before removal, or if the contact surface S2 is used, the front and back orientation is changed to bring the key 231 into contact with the holder 210. In this state, bolts B, B3 and the retaining plate 220 are attached, and bolt B4 is tightened.

[0055] This changes the mounting angle of the holder 210 as defined by the contact surface S1 or S2 of the key 231, and adjusts the auxiliary force provided by the torsion bar 200.

[0056] 16. Torsion bar replacement procedure Figures 13-18 show the procedure for removing the torsion bar 200. To remove the torsion bar 200, first attach the fixing bolt B1 to the fixing part 240 of the bracket 32, from which the pin 41 will be removed later, as shown in Figure 13, and then fix the load receiving platform 40 to the bracket 32.

[0057] Next, as shown in Figure 14, the torsion bar 200 is pushed into the cross member 42 of the loading platform 40 and removed from the holder 210. After removing the torsion bar 200 from the holder 210, the bolt B4 is removed to remove the first part 211 of the holder 210 as shown in Figure 15, and then the bolts B, B3, the retaining plate 220 and the key 231 are removed to remove the second part 212 (pin 41) of the holder 210 as shown in Figure 16. As a result, as shown in Figures 16 and 17, the pin hole 32p of the bracket 32 ​​and the pin hole of the loading platform 40 connected thereto open up on the extension of the torsion bar 200. Since the loading platform 40 is supported by the bracket 32 ​​with fixing bolt B1, its position is maintained even if the pin 41 is removed.

[0058] Once the pin holes 32p are opened in this way, the torsion bars 200 are sequentially removed through the pin holes 32p, as shown in Figure 18.

[0059] The procedure for inserting the Torsion Bar 200 can be done by reversing the steps described above.

[0060] 17. Effects (1) According to this embodiment, by reversing the front and back of the key 231 or changing the contact surfaces S1 and S2 and reattaching it to the bracket 32, the angle of the holder 210 defined by the contact surface S1 or S2 can be changed, and the assisting force provided by the torsion bar 200 when raising the load-receiving platform 40 can be adjusted. Since the mounting position of the key 231 on the bracket 32 ​​is constant, a number of bolt holes used selectively for adjusting the angle of the key 231 is not required. Furthermore, even without additional processing of the bracket 32, the assisting force can be adjusted even more flexibly by separately preparing keys with different contact surface angles, and even when the mounting angle of the holder 210 is further multi-staged, it is possible to avoid increasing the size and complexity of the bracket 32. Thus, the mounting angle of the torsion bar 200, and therefore the assisting force, can be flexibly adjusted with a compact and simple configuration.

[0061] (2) The holder 210 comprises a first part 211 that holds the torsion bar and a second part 212 that sandwiches the bracket 32 ​​between the first part 211 and the second part 212, and a pin 41 that rotatably supports the load receiving platform 40 relative to the bracket 32 ​​is provided on either the first part 211 or the second part 212. The first part 211 and the second part 212 are locked together so as not to rotate. As a result, the holder 210 rotates integrally in the rotational direction of the load receiving platform 40 with the pin 41 as a pivot point, so that, for example, by rotating the second part 212 of the holder 210 from the outside in the left-right direction (vehicle width direction), the first part 211 that holds the torsion bar 200 can be rotated, making it easier to adjust the auxiliary force provided by the torsion bar 200.

[0062] (3) The contact surface S2 of the key 231 changes the angle θ to the ground when the key 231 is flipped over along the axis of symmetry C2 of the connection part of the key 231, so the mounting angle of the holder 210 can be changed using the same contact surface S2.

[0063] (4) The key 231 has a first contact surface S1 and a second contact surface S2 that are not parallel to each other, and by flipping it over on the line symmetry axis C1 of the connection part or rotating it on the rotation symmetry axis C3 and attaching it to the bracket 32, the first contact surface S1 or the second contact surface S2 can be selectively brought into contact with the holder 210. This also makes it possible to change the mounting angle of the holder 210, and the range of selectable mounting angles of the holder 210 can be broadened with a single key 231.

[0064] (5) Furthermore, since the loading platform lifting device 100 has a fixing part 240, by using this fixing part 240 to support the loading platform 40 on the bracket 32, the amount of the loading platform 40 moving relative to the bracket 32 ​​when the pin 41 is removed can be reduced without requiring large-scale equipment such as a crane. Then, by removing the pin 41, the torsion bar 200 can be inserted into and removed from the loading platform 40 through the pin hole 32p which is opened on the extension line of the torsion bar 200. This makes it easier to replace the torsion bar 200.

[0065] (6) Furthermore, since the loading platform 40 is fixed to the bracket 32 ​​by the fixing part 240 in an upright position, the moment load of the loading platform 40 acting on the fixing part 240 is suppressed, and the support state of the loading platform 40 can be stabilized.

[0066] (7) The fixing part 240 can be made up of holes through which fasteners (for example, fixing bolts) pass, and can be made into an extremely simple structure.

[0067] (8) As described above, the holder 210 that holds one end of the torsion bar 200 comprises a first part 211 that holds the torsion bar 200 and a second part 212 that sandwiches the bracket 32 ​​between the first part 211, and the pin 41 that rotatably supports the load receiving platform 40 with respect to the bracket 32 ​​is provided on the second part 212. The pin 41 can be removed by removing the second part 212, which is on the opposite side of the load receiving platform 40 from the bracket 32, that is, on the outside in the left-right direction (vehicle width direction) and is easily accessible. Therefore, good workability can be ensured when inserting and removing the pin 41.

[0068] (9) When the bolt B3 or B used to fix the second part 212 to the bracket 32 ​​is used as a fixing bolt to attach to the fixing part 240, the components of the load-receiving platform lifting device 100 can be used as fixing bolts when replacing the torsion bar 200, and there is no need to procure fixing bolts when replacing the torsion bar 200.

[0069] (10) If a bolt storage compartment for mounting fixing bolts is provided, fixing bolts to be used when replacing the torsion bar 200 can be kept on hand. In this case as well, there is no need to procure fixing bolts when the torsion bar 200 is replaced.

[0070] 18. Postscript The present invention is not limited to the embodiments described above and may include various modifications. For example, the embodiments described above are described in detail for the purpose of clearly illustrating the present invention and are not necessarily limited to those having all the configurations described. For example, it is possible to replace some of the configurations with other configurations. It is also possible to delete some of the configurations of the embodiments or to add other configurations.

[0071] For example, the explanation described the application of the invention to a loading platform lifting device 100 in which the loading platform 40 moves up and down along vertical posts 10L, 10R. However, even in loading platform lifting devices in which the loading platform 40 moves up and down by an arm that rotates up and down, there are cases where an operator manually raises the loading platform to a driving position. In this type of loading platform lifting device, a torsion bar may be installed to obtain an assisting force for raising the loading platform, and the present invention can be applied in the same way as in the loading platform lifting device 100 of the above embodiment. Furthermore, the explanation described the application of the invention to a loading platform lifting device 100 in which the loading platform 40 takes an upright driving position. However, even in underfloor storage type loading platform lifting devices in which the loading platform is folded and retracted under the chassis frame for storage, there are cases where the operator manually prepares to raise the loading platform when folding it. This type of underfloor retractable loading platform lifting device may also be equipped with a torsion bar to provide assistance in raising the loading platform, and the present invention can be applied in the same manner as the loading platform lifting device 100 of the above embodiment.

[0072] Furthermore, while the example illustrates a configuration in which the bent ends of the torsion bar 200 engage with the holding parts of the loading platform 40 and the holder 210, causing the torsion bar 200 to twist as the loading platform 40 rotates, it is also possible to use a torsion bar with a non-circular (e.g., rectangular) cross-section at both ends and no bent parts. In this configuration, the non-circular ends engage with the holding parts of the loading platform 40 and the holder 210, causing the torsion bar 200 to twist as the loading platform 40 rotates. The present invention is also applicable to loading platform lifting devices employing such a torsion bar. In addition, while the example illustrates a holder 210 that can be disassembled into a first part 211 and a second part 212, it is also possible to omit the first part 211 and instead form a recess corresponding to the housing chamber 215 on the end face of the pin 41 of the second part 212, so that the torsion bar 200 directly engages with the pin 41. The present invention is also applicable in this case.

[0073] Furthermore, Figure 19 shows a modified example of the auxiliary force adjustment mechanism 230. In the example of Figure 19, elements identical to or corresponding to those in the above embodiment are denoted by the same reference numerals as in the previously shown drawings, and their descriptions are omitted as appropriate. In the example of Figure 19, two bolt holes 32c (not shown) are arranged vertically, and the key 231 has four contact surfaces Sa-Sd, each with a different angle θ to the ground. The contact surfaces Sa,Sb and Sc,Sd are located on opposite sides of the symmetry axis C1, and the contact surfaces Sa,Sd and Sb,Sc are located on opposite sides of the symmetry axis C2. Figure 19 shows the state in which the contact surface Sa is in contact with the holder 210, but if the key 231 is flipped over along the symmetry axis C1, the contact surface Sd will contact the holder 210 at a different angle. Also, if the key 231 is flipped over along the symmetry axis C2, the contact surface Sb will contact the holder 210 at a different angle. Furthermore, when the key 231 is rotated 180 degrees around the rotational symmetry axis C3, the contact surface Sc contacts the holder 210 at different angles.

[0074] Furthermore, in the above embodiment, the key 231 was in contact with the radially facing surface of the pin 41 against the mounting portion 217 of the second component 212 of the holder 210. However, in this example, the key 231 is in contact with the surface of the mounting portion 217 facing the rotational direction X due to the twisting return force of the torsion bar 200. This configuration can also be adopted in the above embodiment. With this configuration, the force acting on the contact surface between the key 231 and the second component 212 acts at an angle nearly perpendicular to the contact surface, so the influence of the looseness of the key 231 due to the tolerance of the through hole H of the key 231 on the mounting angle of the holder 210 can be suppressed. [Explanation of Symbols]

[0075] 32...Bracket, 32c...Bolt hole (connection part), 40...Loading platform, 41...Pin, 100...Loading platform lifting device, 200...Torsion bar, 210...Holder, 211...First part, 212...Second part, 231...Key, C1, C2...Linear symmetry axis, C3...Rotational symmetry axis, H...Through hole (connection part), S1, S2, Sa-Sd...Contact surface, α...Holder angle, θ...Angle to ground

Claims

1. In a loading platform lifting device that raises and lowers a loading platform relative to a vehicle, A bracket that rotatably supports the aforementioned loading platform, A torsion bar that biases the load-receiving platform in an upright direction relative to the bracket, A holder that holds one end of the torsion bar, The bracket is equipped with a key that is attached to the holder and contacts the holder to restrict the rotation of the holder, The key has at least one contact surface that contacts the holder, and the contact surface is configured to be changeable. A loading platform lifting device characterized by the following features.

2. In the loading platform lifting device according to claim 1, The aforementioned holder is, A first component that holds the torsion bar, The assembly comprises a second component that sandwiches the bracket between the first component and the second component, The first or second part has a pin that rotatably supports the load-receiving platform relative to the bracket. A loading platform lifting device characterized by the following features.

3. In the loading platform lifting device of claim 2, A loading platform lifting device characterized in that the first part and the second part are interlocked with each other in a way that prevents rotation.

4. In a loading platform lifting device according to any of claims 1 to 3, The key and the bracket are engaged at at least one interface, The aforementioned joint portion is formed or arranged in a line-symmetrical manner. The contact surface of the key is not perpendicular and non-parallel to the axis of symmetry of the connection portion, and the angle to the ground changes when the key is flipped over along the axis of symmetry. A loading platform lifting device characterized by the following features.

5. In a loading platform lifting device according to any of claims 1 to 3, The key and the bracket are engaged at at least one interface, The aforementioned joint portion is formed or arranged in a line-symmetrical manner. The key has a first contact surface and a second contact surface that are not parallel to each other, and by inverting it along the axis of symmetry of the connection portion and attaching it to the bracket, the first contact surface or the second contact surface can selectively contact the holder. The first contact surface that abuts the holder and the second contact surface that abuts the holder have different angles relative to the ground. A loading platform lifting device characterized by the following features.

6. In a loading platform lifting device according to any of claims 1 to 3, The key and the bracket are engaged at at least one interface, The aforementioned connection portion is formed or arranged in a rotationally symmetrical manner. The key has a first contact surface and a second contact surface, and by rotating it about the rotational symmetry axis of the connection portion and attaching it to the bracket, the first contact surface or the second contact surface can selectively contact the holder. The first contact surface that abuts the holder and the second contact surface that abuts the holder have different angles relative to the ground. A loading platform lifting device characterized by the following features.

Images