JP3917831B2 - Arm structure of loading platform lifting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a load receiving platform lifting device that is mounted on a rear portion or a side portion of a lorry and is used for loading and unloading loads, and particularly relates to an arm structure thereof.
[0002]
[Prior art and problems to be solved by the invention]
A load receiving table lifting device mounted on the lower rear portion of a vehicle body of a lorry raises and lowers the load receiving table by an arm to which power such as hydraulic pressure is applied to load and unload the load. There are two types of such load receiving platform lifting devices: a slide type in which the arm can move back and forth and a non-slide type in which the fulcrum of the arm is fixed to the vehicle body. The latter is preferred. In this latter case, the arm requires a certain length of arm from a fulcrum (fixed point) provided at the lower part of the vehicle body to an action point for raising and lowering the load receiving table. On the other hand, during normal travel, the load receiving platform lifting device must be compactly stored in the lower part of the vehicle body. In this case, the arm length of the arm is an obstacle. In view of this, it is conceivable that the arm has a folded structure in order to achieve both the arm arm length securing during use and the compactness during storage.
[0003]
However, the arm having the folding structure becomes bulky in the vertical direction due to folding, and therefore, it is difficult to apply to a small and medium-sized vehicle having a small underfloor dimension compared to a large vehicle. Further, since the connecting portion is interposed by the folding structure, the mechanical strength of the entire arm is likely to be lowered.
In view of the above-described conventional problems, an object of the present invention is to provide an arm structure for a load receiving platform lifting apparatus that can be folded compactly and has excellent mechanical strength.
[0004]
[Means for Solving the Problems]
The arm structure of the load receiving platform lifting apparatus of the present invention is provided on the vehicle body as a pair of left and right arm structures of the load receiving platform lifting apparatus for storing, unfolding and lifting the load receiving platform, and each arm structure is
Between a pair of upper and lower fulcrums A and B provided on the vehicle body that can be rotated within a predetermined range, respectively, between a base upper arm and a base lower arm, and action points C and D on the respective rotation end sides of these arms. A base link mechanism that forms a square link having four vertices A, B, C, and D by the connected base connecting members;
A distal end upper arm and a distal end lower arm that are pivotable within a predetermined range about the action points C and D, respectively, and that can be folded with respect to the base link mechanism, and actions on the respective pivot end sides of these arms. A front end connecting member connected between the points E and F forms a square link having C, D, E, and F as four vertices, and supports the load receiving platform on the side of the operating point E or F Part link mechanism,
One of the base lower arm and the tip lower arm is composed of two plates, and the other is a single plate structure connected between the ends of the two plates,
The base lower arm in a state in which the load receiving base is stored has an arcuate shape which is curved so as to protrude downward, and the tip lower arm is folded thereon so that a single plate is provided between the two plates. It is characterized by having a structure to enter .
[0005]
In the arm structure of the load receiving device lifting / lowering device configured as described above, when the lower arm of the tip is folded on the lower arm of the base , the one-plate arm enters between the two-plate arms, and the both overlap. Can do. Accordingly, the size of the folded arms in the vertical direction is reduced. Further, a load is applied to the pins connecting the two-plate arm and the one-plate arm with a good balance in the pin axis direction.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a load receiving table lifting apparatus employing an arm structure according to an embodiment of the present invention will be described with reference to the drawings. FIGS. 1 and 2 are a rear view and a side view, respectively, showing the load receiving platform lifting / lowering device 1 attached to the lower part of the cargo box 102 at the rear part of the body 101 of the truck. In FIG. 2, brackets 2A are attached to both side surfaces of the chassis 104 behind the rear wheel 103, and a support member 2B is attached thereto. The load receiving table elevating device 1 is attached to the support member 2B. 2 is in a traveling state stored in the lower part of the vehicle body 101. As shown in FIG. In use, the vehicle is pulled out from the state of FIG. 2 to the rear of the vehicle body 101 as shown in the order of FIG. 3, FIG. 4, and FIG.
[0007]
Next, the structure of each part of the load receiving platform elevating device 1 will be described with reference to FIG. The load receiving platform lifting / lowering device 1 basically has a two-stage arm structure including a base arm (base lower arm 4, base upper arm 8) and a tip arm (tip lower arm 13, tip upper arm 16). is doing.
In FIG. 4, the base lower arm 4 is rotatable around a pin 5 provided at the left end portion within a predetermined range around the pin 5, and the pin 5 is fixed to the support member 2B. The right end portion of the base lower arm 4 is connected to a base connecting member 7 via a pin 6 as an action point. On the other hand, the base upper arm 8 is rotatable around a pin 9 provided at the left end portion within a predetermined range around the pin 9, and the pin 9 is fixed to the support member 2B. A right end portion of the base upper arm 8 is connected to the base connecting member 7 via a pin 10 as an action point. Here, if the pins 9 and 5 are a pair of upper and lower fulcrums A and B, and the pins 10 and 6 are operating points C and D corresponding to the fulcrums A and B, respectively, the base lower arm 4, the base connecting member 7 and The base upper arm 8 constitutes a base link mechanism having an unequal side quadrangle having A, B, C, and D as four vertices, a side CD longer than the side AB, and a side BD longer than the side AC. A hydraulic cylinder (not shown) is connected to the base upper arm 8, and when the base upper arm 8 is rotated by the supply of hydraulic pressure, the base lower arm 4 is also rotated accordingly. The base upper arm 8 is formed by fixing two steel materials of the same shape arranged in the vehicle body width direction to each other by a channel material 11. The channel material 11 serves to reinforce the base upper arm 8 and also controls the rotation of the tip upper arm 16. That is, in the retracted state of FIG. 2, the tip portion (pin 17 side) of the tip end upper arm 16 comes into contact with the upper surface of the channel material 11, and the tip end top arm 16 further rotates counterclockwise. Is regulated.
[0008]
Next, in FIG. 4, the tip end lower arm 13 is pivotally attached to the base lower arm 4 by a pin 6 and is attached to be rotatable in a predetermined range in the counterclockwise direction from the illustrated position. The right end of the tip lower arm 13 is connected to the tip connecting member 15 via a pin 14 as an action point. Further, the L-shaped tip upper arm 16 is pivotally attached to the base upper arm 8 by a pin 10 and can be rotated counterclockwise within a predetermined range. Is detented. The right end of the tip upper arm 16 is connected to the tip connecting member 15 through a pin 17 as an action point. Here, assuming that the pins 17 and 14 are the action points E and F, respectively, the distal end lower arm 13, the distal end connecting member 15 and the distal end upper arm 16 are parallel four sides having C, D, E and F as four vertices. A tip end link mechanism having a shape is formed.
[0009]
In the base link mechanism (ABCD), the tip end link mechanism (CDEF), and the load receiving platform 18 supported by the tip end link mechanism, the position shown by the solid line in FIG. At the end.
Further, the distal end link mechanism (CDEF) can be folded as shown in FIGS. 3 and 2 by rotating counterclockwise with respect to the base link mechanism (ABCD).
[0010]
On the other hand, in FIG. 5, the load receiving stand 18 is also a foldable structure, and includes a main plate 19 and a sub plate 20. The sub-plate 20 can be rotated counterclockwise from the illustrated position with respect to the main plate 19 (see FIG. 4). The main plate 19 is attached so as to be able to turn counterclockwise from the illustrated position with the pin 17 as a support point. Further, the stopper 21 attached to the main plate 19 is in contact with the right end surface of the tip end connecting member 15. The guide plate 22 protruding from the left end of the main plate 19 serves to fill a gap between the floor surface of the load box 102 and the load receiving platform 18 when loading and unloading the load. The guide roller 23 engages with the load receiving table 18 when the load receiving table lifting device 1 is stored, and guides it. The guide roller 23 is rotatably supported by a guide roller support member 24 fixed to the support member 2B.
[0011]
Next, the raising / lowering mechanism of the load receiving stand 18 will be described. FIG. 6 is a side view showing in principle the load receiving platform 18 and an arm structure composed of a base link mechanism and a tip link mechanism for raising and lowering the load receiving table 18, and the reference numerals of the respective parts are the same as those in FIGS. 2 to 5. . The base link mechanism is represented by an unequal side rectangle ABCD, where A and B are fixed points and C and D are movable points. The tip link mechanism is represented by a parallelogram CDEF, and each vertex C, D, E, F is a movable point. When the base lower arm 4 and the base upper arm 8 are rotated within the range shown in the drawing, the distal end is connected to the rotating end side and is prevented from rotating in the clockwise direction with respect to the base upper arm 8. The upper arm 16 rotates integrally, and the tip end lower arm 13 also rotates following this. The side CD and the side EF are always parallel to each other, and the load receiving stand 18 always maintains a constant posture with respect to the side EF. Therefore, the inclination of the receiving tray 18 is determined by the inclination of the side CD. On the other hand, as long as the inclination of the side CD is constant, the posture of the load receiving stand 18 is constant and always lateral. For example, the load receiving stand 18 in the state shown in FIG. 3 is different from the state shown in FIG. 5 in that the sub-plate 20 is folded, but the inclination of the side CD is unchanged. Accordingly, the posture of the load receiving platform 18 (inclination of the main plate 19) is completely the same in the range shown in FIG. 3 and the state shown by the solid line in FIG.
[0012]
In addition, as shown in FIG. 6, the distal end link mechanism (CDEF) has an inclination angle steeper than the inclination angle of the base upper arm 8 at the rising end of the base upper arm 8, and is It plays a role of further pushing up the EF and the receiving platform 18. Therefore, it is possible to push up the load receiving platform 18 to a predetermined height while suppressing the rotation range of the base link mechanism (ABCD). In addition, it is possible to avoid interference between the base arm or the like and the load box 102 at the rising end of the load receiving platform. Conversely, at the descending end of the base upper arm 8, the distal end link mechanism has an inclination angle that is gentler than the inclination angle of the base upper arm 8, and suppresses the lowering of the side EF and the load receiving table 18 with respect to the side CD. Playing a role.
[0013]
In this embodiment, the lengths of the sides AB, CD, AC and BD of the base link mechanism (ABCD) are configured such that AB <CD and AC <BD. Such a magnitude relationship between two opposing sides affects the link operation.
FIG. 7 is a diagram showing how the size relationship between sides AB and CD in a link mechanism having an unequal side square affects the link operation, in addition to the actual arrangement shown in FIG. (A) shows the link operation when AC = BD and AB <CD, and (b) shows the link operation when AB> CD.
[0014]
In (a), in the state shown by the solid line, the sides AB and CD are both vertical, but the side CD is tilted to the left as shown by the two-dot chain line by raising the rotation side of the link mechanism. Further, the side CD is inclined to the right as the pivot side of the link mechanism is lowered. On the other hand, in (b), in the state shown by the solid line, the sides AB and CD are both vertical, but the side CD is inclined to the right as shown by the two-dot chain line by raising the rotation side of the link mechanism. . Further, the side CD is tilted to the left as the rotation side of the link mechanism is lowered. That is, in (a) and (b), the inclination direction of the side CD accompanying the rotation of the link mechanism is opposite.
Further, in (a), when AC> BD, the inclination angle of the side CD with respect to the vertical at the time of ascent and descent decreases. Conversely, when AC <BD, the inclination angle of the side CD with respect to the vertical at the time of ascent and descent increases. Further, in (b), when AC> BD, the inclination angle of the side CD with respect to the vertical at the time of ascent and descent increases. Conversely, when AC <BD, the inclination angle of the side CD with respect to the vertical at the time of ascent and descent decreases.
[0015]
Based on the above, based on the magnitude relationship between AB and CD (including the case where they are equal), an unequal-sided quadrilateral that further takes into account the magnitude relationship between AC and BD (including cases where they are equal) as necessary. By configuring the link mechanism, it is possible to adjust the inclination of the side CD with respect to the side AB that occurs as the link rotates to a desired level. In the present embodiment, as described above, the relationship of AB <CD and AC <BD is employed.
[0016]
Returning to FIG. 6, the side CD and the side EF are inclined leftward at the rising end of the base link mechanism (ABCD). In this state, the load receiving stand 18 is supported substantially horizontally. When the base link mechanism descends from this state, the side CD and the side EF tilt gently. At the descending end, the inclination angles of the side CD and the side EF are smaller than those at the ascending end, and the load receiving stand 18 is tilted. That is, the tilting operation of the load receiving platform 18 is not performed separately from the lifting operation, but is performed integrally with the lifting operation. Therefore, a dedicated structure for the tilt operation is not necessary, and the structure is simple. Further, this tilting operation is performed very smoothly and does not involve an impact. Accordingly, it is possible to prevent the luggage from falling or falling. On the other hand, when moving from the descending end to the ascending end, similarly, the load receiving platform 18 changes its posture from the tilted state to the horizontal very smoothly.
[0017]
Next, the arm structure will be described in more detail. FIG. 8 is an exploded perspective view of the arm structure (an example on the left side when viewed from the rear of the vehicle body). In the figure, the base upper arm 8 is composed of two plates as described above, and the tip end upper arm 16 composed of a single plate is connected between the ends of the two plates. On the other hand, the tip end lower arm 13 is composed of two plates, and between the ends of the two plates, a base lower arm 4 consisting of a single plate (however, pipe-like members are welded to both ends). The connection is made. Further, as described above, the above-described CD is connected by the base connecting member 7, and the EF is connected by the tip connecting member 15. That is, both the upper arm (base upper arm 8 and distal end upper arm 16) and lower arm (base lower arm 4 and distal lower arm 13) have a structure in which a two-plate arm and a single-plate arm are connected. It has become. In such a structure, the pins 10 and 6 (see FIG. 4 and the like) inserted through C and D are loaded in a balanced manner in the pin axis direction. Accordingly, the distal end arm (the distal end upper arm 16 and the distal end lower arm 13) is held in parallel to the base arm (the base upper arm 8 and the base lower arm 4), and the connecting portion and the entire arm are mechanically operated. Excellent strength.
[0018]
FIG. 9A is a schematic diagram showing a state in which the connection parts according to C and D are viewed from above. Since the strength per sheet may be relatively small by adopting the two-plate structure, the plate thickness of the base upper arm 8 and the tip lower arm 13 is thinner than the base lower arm 4 and the tip upper arm 16. If the two-plate structure is not adopted and all the arms (4, 8, 13, 16) are constituted by a single plate as shown in (b), a predetermined plate is attached to each arm. Thickness is required, and the width of the total plate thickness in the vehicle body width direction is w1 and w2. In the case of (a), the base upper arm 8 and the tip upper arm 16 of the two plates occupy. If the width is w1 and the width occupied by the lower end arm 13 and the lower base arm 4 of the two plates is w2, the same mechanical strength as in the case of (b) is secured. Therefore, even if the two-plate structure is adopted, the necessary mechanical strength can be ensured without enlarging the entire arm in the vehicle body width direction.
[0019]
FIG. 10 is a diagram showing only the base lower arm 4 and the tip lower arm 13 by solid lines in the load receiving table lifting apparatus 1 (see FIG. 2) in the state of being stored in the vehicle body. As shown in the figure, the front end lower arm 13 of the two plates sandwiches the base lower arm 4 of the single plate by folding, and the hatched regions X1 and X2 overlap each other when viewed from the side. Part. Due to such superposition, in this state, the dimension occupied by the base lower arm 4 and the tip lower arm 13 in the vertical direction is extremely small. Therefore, the entire cargo receiving platform lifting / lowering apparatus 1 can be folded compactly.
In the present embodiment, only the lower arm is configured to have an overlapping region at the time of folding. Instead of this, a similar overlapping region can be formed by devising the shape of the upper arm side. It is also possible to configure.
[0020]
Further, in the present embodiment, the base upper arm 8 and the tip lower arm 13 are each two plates, but conversely, these are one plate and the base lower arm 4 and the tip upper arm 16 are each two plates. You can also Furthermore, in the present embodiment, the upper arm (base upper arm 8 and distal end upper arm 16) and lower arm (base lower arm 4 and distal end lower arm 13) both employ a two-plate structure. For only one of them, a two-plate structure may be adopted.
[0021]
A series of operations (from pulling up and down and storing) in the load receiving table lifting apparatus 1 configured as described above will be described with reference to FIGS.
First, after stopping the vehicle and pulling the parking brake, the hydraulic cylinder is driven from the state shown in FIG. 2 to rotate the base upper arm 8 and the base lower arm 4 clockwise to the lower end. As a result, the load receiving base 18 is pushed away by the guide roller 23, and the distal end lower arm 13 and the distal end upper arm 16 are slightly opened clockwise around the pins 6 and 10, respectively, as shown in FIG. To.
[0022]
Next, the operator pulls the folded cargo receiving tray 18 backward by hand. As a result, the distal end lower arm 13 and the distal end upper arm 16 rotate in the clockwise direction around the pin 6 and the pin 10, respectively. During this rotation, the parallelogram CDEF formed by the pins 10, 6, 17 and 14 changes its shape, but the side CD and the side EF maintain a parallel relationship with each other. Accordingly, the load receiving platform 18 descends while maintaining a certain posture, and reaches near the floor as shown in FIG. Thereafter, the operator raises and rotates the sub-plate 20 of the load receiving table 18 by hand, and unfolds as shown in FIG.
[0023]
When unloading a load, the hydraulic cylinder is driven to rotate the base upper arm 8 and the base lower arm 4 counterclockwise. In accordance with this, the tip end upper arm 16 and the tip end lower arm 13 also rotate, and the load receiving stand 18 rises. During this ascent, the side CD of the base link mechanism (ABCD) is gradually tilted with respect to the side AB, so that the side EF of the tip end link mechanism (CDEF) is similarly tilted. Gradually level from the state. In this way, the load receiving stand 18 rises to the rising end indicated by the two-dot chain line in FIG. 5 where the load receiving stand 18 and the floor surface of the load box 102 coincide. Here, the operator transfers the load from the load box 102 to the load receiving platform 18. After the transfer, the hydraulic cylinder is driven to rotate the base upper arm 8 and the base lower arm 4 in the clockwise direction. In accordance with this, the distal end upper arm 16 and the distal end lower arm 13 are also rotated, and the load receiving table 18 is lowered. During the lowering, the side CD of the base link mechanism is gradually tilted with respect to the side AB, so that the side EF is similarly tilted, and the load receiving platform 18 is gradually shifted from the substantially horizontal state to the tilted state. Reach the falling edge. Accordingly, no impact is applied to the load, and the load can be prevented from falling or falling.
When loading a package into the packing box 102, the above operations are performed in the reverse order.
[0024]
Next, when storing the load receiving platform lifting / lowering device 1, the operator folds the sub-plate 20 from the state shown by the solid line in FIG. 5, and then lifts the folded load receiving stand 18. Return to the state shown in FIG. Here, the hydraulic cylinder is driven to rotate the base upper arm 8 and the base lower arm 4 counterclockwise. Thereby, the cargo receiving stand 18 is in the state shown in FIG. 2 and is stored in the lower part of the vehicle body 101.
[0025]
In addition, in the said embodiment, although the load receiving platform raising / lowering apparatus 1 demonstrated as what was pulled out back of the vehicle body 101, even if it is the structure pulled out to the side, it can apply similarly.
Further, the main plate 19 of the load receiving platform 18 is rotatably attached with the pin 17 as a support point. However, the main plate 19 may be rotatably attached with a pin provided separately from the pin 17 as a support point. It is also possible to pivotally attach the pin 14 as a support point.
Further, the arm structure of the present embodiment can also be applied to a load receiving table lifting device in which the base link mechanism can slide in the horizontal direction.
[0026]
【The invention's effect】
The present invention configured as described above has the following effects.
According to the arm structure of the load receiving platform lifting / lowering apparatus of the present invention, when the tip end lower arm is folded on the base lower arm, a single plate arm enters between the two plate arms, and an area where both overlap is formed. Therefore, the dimension which both arms occupy in the up-down direction becomes small. Therefore, the load receiving platform lifting device can be folded compactly. In addition, a load is applied to the pins connecting the two-plate arm and the one-plate arm in a balanced manner in the pin axis direction. Therefore, the said load receiving table raising / lowering apparatus is excellent also in mechanical strength.
[Brief description of the drawings]
FIG. 1 is a rear view of a state in which a cargo receiving platform lifting device including an arm structure according to an embodiment of the present invention is attached to a lower part of a cargo box at a rear part of a vehicle body of a truck.
FIG. 2 is a side view of the load receiving table lifting device, showing a state of being stored in a vehicle body.
FIG. 3 is a side view of the load receiving table lifting device, showing a state during expansion or storage.
FIG. 4 is a side view of the load receiving table lifting device, showing a state in which the distal end link mechanism is expanded with respect to the base link mechanism and the load receiving table is folded.
FIG. 5 is a side view of the load receiving table lifting device, showing a state in which the tip link mechanism and the load receiving platform are deployed and moved up and down.
FIG. 6 is a side view showing in principle a load receiving platform in the load receiving platform elevating device and an arm structure including a base link mechanism and a tip link mechanism for moving the load receiving platform up and down.
FIG. 7 is a diagram showing how a size relationship between sides AB and CD in a link mechanism having an unequal side rectangle generally affects a link operation;
8 is an exploded perspective view of the arm structure (example on the left side when viewed from the rear of the vehicle body) shown in FIGS.
FIG. 9A is a schematic diagram showing a state in which the connecting portion of the arm structure is viewed from above. (B) is the schematic which shows the state which looked at the said connection part from the top when supposing that all the arms were comprised with the 1 sheet board.
FIG. 10 is a side view showing only the base lower arm and the tip lower arm of the load receiving table lifting device in the state of being housed in the vehicle body, and these are shown by solid lines.
[Explanation of symbols]
1 Cargo stand lifting device 4 Base lower arm 5 Pin (B)
6 pin (D)
7 Base connecting member 8 Base upper arm 9 Pin (A)
10 pin (C)
13 Tip arm 14 pin (F)
15 Tip connection member 16 Tip upper arm 17 Pin (E)
18 Cargo stand 101 Car body 104 Chassis ABCD Base link mechanism CDEF Tip link mechanism

Claims (1)

A pair of left and right arms are provided on the vehicle body as the arm structure of the load receiving table lifting device for storing, unfolding and lifting the load receiving table.
Between a pair of upper and lower fulcrums A and B provided on the vehicle body that can be rotated within a predetermined range, respectively, between a base upper arm and a base lower arm, and action points C and D on the respective rotation end sides of these arms. A base link mechanism that forms a square link having four vertices A, B, C, and D by the connected base connecting members;
A distal end upper arm and a distal end lower arm that are pivotable within a predetermined range about the action points C and D, respectively, and that can be folded with respect to the base link mechanism, and actions on the respective pivot end sides of these arms. A front end connecting member connected between the points E and F forms a square link having C, D, E, and F as four vertices, and supports the load receiving platform on the side of the operating point E or F Part link mechanism,
One of the base lower arm and the tip lower arm is composed of two plates, and the other is a single plate structure connected between the ends of the two plates,
The base lower arm in a state in which the load receiving base is stored has an arcuate shape which is curved so as to protrude downward, and the tip lower arm is folded thereon so that a single plate is provided between the two plates. An arm structure for a cargo receiving platform lifting device, wherein the arm structure is a structure for entering .

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