JP2003025897A - Arm structure of cargo receiving block lifting unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arm structure of a cargo receiving block lighting unit that can be folded compactly and has high mechanical strength. SOLUTION: An upper arm 16 of the tip comprising one plate is connected between the ends of upper arms 8 of the base comprising two plates, and a lower arm 4 of the base comprising one plate is connected between the ends of lower arms 13 of the tip comprising two plates. The lower arms 13 of the tip grip the lower arm 4 of the base in storing, thereby decreasing a vertical size.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loading / unloading device which is mounted on the rear or side of a truck and is used for loading and unloading cargo, and in particular, its arm. Regarding the structure. 2. Description of the Related Art A cradle lifting device mounted on a rear lower portion of a truck body of a lorry vehicle lifts and lowers the cradle by an arm to which power such as hydraulic pressure is applied to load the luggage. It is intended to load and unload. There are 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. However, in order to simplify the structure and reduce the cost, The latter is preferred. In the latter case, the arm needs to have a fixed arm length from a fulcrum (fixed point) provided at the lower part of the vehicle body to an action point for raising and lowering the loading tray. On the other hand, during normal running, the loading / unloading device must be compactly stored in the lower part of the vehicle body, and conversely, the length of the arm is an obstacle. Therefore, it is conceivable that the arm has a folding structure in order to achieve both the securing of the arm length during use and the compactness during storage. [0003] However, the arms having the folded structure are taller in the vertical direction due to the folding so as to be folded, and therefore, it is difficult to apply them to small and medium-sized vehicles which have no room for underfloor dimensions compared to large vehicles. In addition, since the connecting portion is interposed by the folded structure, the mechanical strength of the entire arm is easily reduced. In view of the above-mentioned conventional problems, an object of the present invention is to provide an arm structure of a loading / unloading device that can be folded compactly and has excellent mechanical strength. [0004] The arm structure of the loading tray lifting device according to the present invention is provided as a pair of left and right arm structures of a loading tray lifting device for storing, unfolding and lifting the loading tray. The structure has a base upper arm and a base lower arm rotatable within a predetermined range around a pair of upper and lower fulcrums A and B provided on the vehicle body side, and action points C and D on the respective rotating end sides of these arms. A base link mechanism that forms a square link having four vertices of A, B, C, and D by a base connecting member connected therebetween, and rotates within a predetermined range around the action points C and D, respectively. A distal end upper arm and a distal end lower arm, which are foldable with respect to the base link mechanism, and a distal end link connected between action points E and F on the respective rotating end sides of these arms. A top end link mechanism that forms a square link having four vertices with C, D, E and F at the application point E or F side, and the base upper arm and the front end The upper arm is a set of upper arms, the lower arm of the base and the lower end of the arm are a pair of lower arms, the common name of the upper arm of the base and the lower arm of the base is the base arm, and the upper arm of the distal end and the lower end of the tip. When the common name of the arm is a distal arm, at least one of the upper arm and the lower arm, one of the base arm and the distal arm is formed of two plates, and the other is provided between the ends of the two plates. It is characterized by a single-plate structure connected. In the arm structure of the lifting / lowering device configured as described above, the arm of the single plate enters between the arms of the two plates at the time of folding, and an area where both arms overlap is formed. Therefore, the dimension occupied by the two arms in the folded state in the vertical direction is reduced. Also, a two-plate arm and one
A load is applied to the pins connecting the arms of the plate to each other in the axial direction of the pins with good balance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an explanation will be given of a loading tray lifting apparatus employing an arm structure according to an embodiment of the present invention with reference to the drawings. FIGS. 1 and 2 are a rear view and a side view, respectively, showing a loading tray elevating device 1 attached below a packing box 102 at a rear portion of a body 101 of a truck.
In FIG. 2, the chassis 104 behind the rear wheel 103
A bracket 2A is attached to each of both side surfaces of the
The support member 2B is attached to this. The loading table lifting device 1 is attached to the support member 2B. 2 is in a running state stored in the lower part of the vehicle body 101. And at the time of use,
From the state shown in FIG. 3, FIG. 4, and FIG.
01 and is unfolded. Next, the structure of each part of the loading tray lifting device 1 will be described with reference to FIG. Basically, the loading / unloading device 1 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). are doing. In FIG. 4, the base lower arm 4 is
A pin 5 provided at the left end portion can be pivoted in a predetermined range around the pin 5 as a fulcrum.
Fixed to. The right end 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 within a predetermined range around a pin 9 provided at the left end as a fulcrum, and the pin 9 is fixed to the support member 2B. The right end of the base upper arm 8 is connected to the base connecting member 7 via a pin 10 as an action point. Here, the pins 9 and 5 are a pair of upper and lower fulcrums A and B, and the pins 10 and 6 are action points C and D corresponding to the fulcrums A and B, respectively.
Then, the lower base arm 4, the base connecting member 7, and the upper base arm 8 have A, B, C, and D as the four vertices, and the side CD
Is longer than the side AB, and the side BD is a base link mechanism composed of a scalene rectangle 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 rotates by the supply of hydraulic pressure, the base lower arm 4 also rotates accordingly. Base upper arm 8
Is formed by fixing two steel materials of the same shape arranged in the width direction of the vehicle body to each other by a channel material 11. The channel material 11 not only serves to reinforce the base upper arm 8, but also controls the rotation of the distal upper arm 16.
That is, in the retracted state of FIG.
The front end (pin 17 side) of 6 abuts on the upper surface of the channel material 11 to restrict the tip upper arm 16 from rotating further counterclockwise. Next, referring to FIG.
Is pivotally attached to the base lower arm 4 by a pin 6, and is attached so as to be rotatable in a predetermined range in a counterclockwise direction from a position shown in the figure. The right end of the distal end lower arm 13 is connected to a distal end connecting member 15 via a pin 14 as an action point. Further, the L-shaped tip upper arm 16 is pivotally mounted on the base upper arm 8 by the pin 10 and is rotatable counterclockwise within a predetermined range, and conversely, clockwise from the illustrated position. Is detented. The right end of the distal end upper arm 16 is connected to the distal end connecting member 15 via a pin 17 as an action point. Here, pin 1
Assuming that points 7 and 14 are action points E and F, respectively, the tip lower arm 13, the tip connecting member 15, and the tip upper arm 16 are formed of parallelograms having C, D, E, and F as four vertices. This constitutes a partial link mechanism. In the base link mechanism (ABCD), the tip link mechanism (CDEF), and the loading tray 18 supported by the tip link mechanism, the position indicated by the solid line in FIG. The position is the rising end. The tip link mechanism (CDEF) can be folded as shown in FIGS. 3 and 2 by rotating counterclockwise with respect to the base link mechanism (ABCD). On the other hand, in FIG. 5, the receiving table 18 also has a foldable structure, and is constituted by a main plate 19 and a sub-plate 20. Sub plate 20
Is rotatable counterclockwise with respect to the main plate 19 from the illustrated position (see FIG. 4). The main plate 19 is attached so as to be rotatable in a counterclockwise direction from the position shown in the figure with the pin 17 as a support point. The stopper 21 attached to the main plate 19 is in contact with the right end surface of the distal end connecting member 15. The guide plate 22 protruding from the left end of the main plate 19 fills a gap between the floor of the packing box 102 and the load receiving tray 18 when loading and unloading luggage. The guide roller 23 engages with and guides the loading tray 18 when the loading tray lifting device 1 is stored. The guide roller 23 is rotatably supported by a guide roller support member 24 fixed to the support member 2B. Next, a description will be given of a lifting mechanism of the receiving table 18. FIG. 6 is a side view principally showing the load receiving table 18 and an arm structure including a base link mechanism and a distal end link mechanism for raising and lowering the same.
5 to FIG. The base linkage is represented by a trapezoidal ABCD, where A and B are fixed points, C and D
Is a movable point. The tip link mechanism is represented by a parallelogram CDEF, and all vertices C, D, E, and F are movable points. When the lower base arm 4 and the upper base arm 8 rotate within the range shown in the figure, the distal end portion is connected to the rotation end side and is provided with the base upper arm 8 being prevented from rotating in the clockwise direction. The upper arm 16 rotates integrally,
Following this, the tip lower arm 13 also rotates. Edge CD
And the side EF are always parallel to each other, and the receiving table 18 always maintains a constant attitude with respect to the side EF. Therefore, the inclination of the receiving tray 18 is determined by the inclination of the side CD. Conversely, as long as the inclination of the side CD is constant, the attitude of the loading table 18 is constant and always horizontal. For example, the receiving table 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. Therefore, the attitude of the loading tray 18 (the inclination of the main plate 19) is completely the same between the state shown in FIG. 3 and the state shown by the solid line in FIG. As shown in FIG. 6, the tip end link mechanism (CDEF) has a steeper inclination angle at the rising end of the base upper arm 8 than the inclination angle of the base upper arm 8 so that the side CD On the other hand, it plays the role of further pushing up the side EF and the loading tray 18. Therefore, it is possible to push up the receiving tray 18 to a predetermined height while suppressing the rotation range of the base link mechanism (ABCD). In addition, interference between the base arm and the like and the packing box 102 can be avoided at the rising end of the receiving table. Conversely, at the lower end of the upper base arm 8, the distal end link mechanism has a gentler inclination angle than the inclination angle of the upper base arm 8, and suppresses the lowering of the side EF and the loading tray 18 with respect to the side CD. Plays a role. The relationship between the lengths of the sides AB, CD, AC, and BD of the base link mechanism (ABCD) in the present embodiment is such that AB <CD and AC <BD. Such a magnitude relationship between the two opposing sides affects the link operation. FIG. 7 is a diagram showing how the magnitude relationship between the sides AB and CD in a generally inequilateral quadrangular link mechanism affects the link operation, apart from the actual arrangement shown in FIG. (A) shows a link operation when AC <BD and AB <CD, and (b)
Indicates a link operation when AB> CD. In (a), in the state shown by the solid line, both sides AB and CD are vertical, but the side CD is inclined leftward as shown by the two-dot chain line because the pivot side of the link mechanism is raised. I do. Further, the side CD is inclined rightward as the pivot side of the link mechanism descends. On the other hand, in the state (b), in the state shown by the solid line, the sides AB and CD are both vertical, but the side CD inclines rightward as shown by the two-dot chain line when the pivot side of the link mechanism rises. . Also, when the rotating side of the link mechanism is lowered, the side CD is lowered.
Tilts to the left. That is, in (a) and (b),
The direction of inclination of the side CD associated with the rotation of the link mechanism has an opposite relationship. Further, if AC> BD in (a), the inclination angle of the side CD with respect to the vertical at the time of ascent and descent is reduced. Conversely, when AC <BD, the inclination angle of the side CD with respect to the vertical at the time of ascending and descending increases. In (b), if AC> BD,
At the time of ascent and descent, the inclination angle of the side CD with respect to the vertical increases. Conversely, if AC <BD, the inclination angle of the side CD with respect to the vertical at the time of ascending and descending decreases. From the above, based on the magnitude relationship between AB and CD (including the case where they are equal), if necessary, the magnitude relationship between AC and BD (including the case where they are equal).
The side C with respect to the side AB generated with the rotation of the link by configuring the inequilateral quadrangular link mechanism in consideration of
The slope of D can be adjusted to a desired degree. In the present embodiment, the relationship of AB <CD and AC <BD is adopted as described above. Returning to FIG. 6, a base link mechanism (ABCD)
At the rising end of the side, the side CD and the side EF are inclined leftward. In this state, the receiving table 18 is supported substantially horizontally. When the base link mechanism moves downward from this state, the side CD and the side EF tilt gently. At the lower end, the inclination angles of the side CD and the side EF become smaller than at the upper end, and the load receiving table 18 is in a tilted state. That is, the tilting operation of the receiving table 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 required, and the structure is simple. Further, this tilt operation is performed extremely smoothly, and does not involve an impact. Therefore, it is possible to prevent the load from falling or falling. Conversely, when moving from the descending end to the ascending end, similarly, the loading table 18 changes its posture from the tilted state to the horizontal very smoothly. 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 distal upper arm 16 composed of a single plate is connected between the ends of the two plates. On the other hand, the tip lower arm 13 is composed of two plates,
A base lower arm 4 made of a single plate between the ends of the two plates
(However, pipe-shaped members are welded to both ends.)
Connection has been made. Further, as described above, the above-described CD is connected by the base connecting member 7, and the EF is connected by the distal connecting member 15. That is, the upper arm (the base upper arm 8 and the distal end upper arm 1
6) and the lower arm (the lower base arm 4 and the lower end arm 13) both have a structure in which a two-plate arm and a one-plate arm are connected. Such a structure is known as C and D
The load is applied to the pins 10 and 6 (see FIG. 4 and the like) inserted in the pin shaft in a balanced manner in the pin axis direction. Therefore, the distal arm (the distal upper arm 16 and the distal lower arm 1) is moved with respect to the base arm (the upper upper arm 8 and the lower lower arm 4).
3) are held in parallel, and the mechanical strength of the connection portion and the arm as a whole is excellent. FIG. 9A is a schematic view showing a state in which the connection portions relating to C and D are viewed from above. By adopting the two-plate structure, the strength per sheet may be relatively small,
The plate thickness of the base upper arm 8 and the distal end lower arm 13 is thinner than the base lower arm 4 and the distal end upper arm 16. If the two-plate structure is not adopted and all the arms (4, 8, 13, 16) are constituted by one plate as shown in FIG. Assuming that w1 and w2 are widths occupied by the sum of the plate thicknesses in the vehicle body width direction, in the case of (a), the base upper arm 8 and the distal end upper arm 16 of the two plates occupy. The width is w1 and 2
If the width occupied by the lower arm 13 at the distal end and the lower arm 4 at the base of the sheet is w2, the same mechanical strength as in the case (b) is secured. Therefore, even if a two-plate structure is adopted, necessary mechanical strength can be secured without enlarging the entire arm in the vehicle body width direction. FIG. 10 is a diagram showing only the base lower arm 4 and the distal end lower arm 13 of the loading tray lifting device 1 (see FIG. 2) stored in the vehicle body by solid lines. As shown in the drawing, the distal 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, the size occupied by the base lower arm 4 and the distal end lower arm 13 in the vertical direction in this state is extremely small. Therefore, the loading platform lifting device 1
The whole can be folded compactly. In the present embodiment, only the lower arm is configured to have a superimposed region at the time of folding, but instead or additionally, the shape of the upper arm is devised so that a similar superimposed region can be formed. It is also possible to configure. In the present embodiment, the base upper arm 8 and the distal end lower arm 13 are each made of two plates.
These may be formed as one plate, and the base lower arm 4 and the distal end upper arm 16 may each be formed as two plates. Further, in this embodiment, both the upper arm (the base upper arm 8 and the distal end upper arm 16) and the lower arm (the base lower arm 4 and the distal end lower arm 13) adopt a two-plate structure. For only one of them, a two-plate structure may be adopted. The lifting / lowering device 1 configured as described above
Will be described with reference to FIGS. 2 to 5. First, after stopping the vehicle and applying 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 descending ends. Along with this, the receiving table 18 is pushed away by the guide roller 23, and the distal end lower arm 13 and the distal end upper arm 1 are moved.
6 slightly opens clockwise around the pins 6 and 10, respectively, to reach the state shown in FIG. Next, the operator pulls out the folded receiving tray 18 by hand. As a result, the distal end lower arm 13 and the distal end upper arm 16 rotate clockwise around the pins 6 and 10, respectively. During this rotation,
The parallelogram CDEF formed by the pins 10, 6, 17, and 14 changes its shape, but maintains a parallel relationship between the side CD and the side EF. Accordingly, the loading tray 18 descends while maintaining a constant posture, and reaches near the floor as shown in FIG. Thereafter, the operator raises and rotates the sub-plate 20 of the loading tray 18 by hand, and unfolds the sub-plate 20 as shown in FIG. When unloading the luggage, the hydraulic cylinder is driven to rotate the base upper arm 8 and the base lower arm 4 counterclockwise. Accordingly, the distal end upper arm 16 and the distal end lower arm 13 also rotate, and the load receiving table 18 is raised. During this ascent, the base link mechanism (AB
When the side CD of (CD) gradually tilts with respect to the side AB, the side EF of the tip end link mechanism (CDEF) also tilts in the same manner, and the load receiving table 18 gradually becomes horizontal from the tilt state. In this manner, the loading tray 18 is moved up to the rising end indicated by the two-dot chain line in FIG.
Rises. Here, the operator transfers the package from the packing box 102 to the receiving table 18. After the transfer, the hydraulic cylinder is driven to rotate the base upper arm 8 and the base lower arm 4 clockwise. Accordingly, the distal end upper arm 16 and the distal end lower arm 13 also rotate, and the load receiving table 18 is lowered. During the downward movement, the side CD of the base link mechanism is moved to the side AB.
, The side EF also tilts in the same manner, and the load receiving table 18 gradually shifts from the substantially horizontal state to the tilt state to reach the lower end. Therefore, no impact is applied to the load, and the load can be prevented from falling or falling.
When loading the luggage in the packing box 102, the above-described operations are performed in reverse order. Next, when storing the loading tray lifting device 1, the operator folds the sub-plate 20 from the state shown by the solid line in FIG. 5 to the state shown in FIG. And 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. This allows
The loading tray 18 is in the state shown in FIG. In the above embodiment, the loading tray lifting device 1 has been described as being pulled out to the rear of the vehicle body 101. However, a configuration in which the loading tray lifting device 1 is pulled out to the side is also applicable. Further, although the main plate 19 of the loading tray 18 is rotatably mounted with the pin 17 as a support point, the main plate 19 may be rotatably mounted with a pin provided separately from the pin 17 as a support point, or It is also possible to pivotally mount the pin 14 as a supporting point. Further, the arm structure of the present embodiment can also be applied to a loading tray elevating device in which the base link mechanism can slide horizontally. The present invention configured as described above has the following effects. According to the arm structure of the loading tray elevating device of the present invention, when folded, the arm of one plate enters between the arms of two plates, and an area where both arms overlap with each other is formed. Become smaller. Therefore, the loading tray 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 to each other in a well balanced manner in the pin axis direction. Accordingly, the loading / unloading device is excellent in mechanical strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a rear view of a state in which a loading tray elevating device including an arm structure according to an embodiment of the present invention is mounted below a packing box at a rear part of a body of a truck. FIG. 2 is a side view of the loading tray elevating device, showing a state where it is stored in a vehicle body. FIG. 3 is a side view of the lifting / lowering device, showing a state in which the loading / unloading device is being deployed or stored. FIG. 4 is a side view of the loading tray elevating device, showing a state in which a leading end link mechanism is deployed with respect to a base link mechanism and the loading tray is folded. FIG. 5 is a side view of the loading tray elevating device, showing a state in which the leading end link mechanism and the loading tray are expanded and moved up and down. FIG. 6 is a side view showing in principle the load receiving table in the load receiving table elevating device and an arm structure including a base link mechanism and a distal end link mechanism for raising and lowering the load receiving table. FIG. 7 shows a side A in a generally inequilateral quadrangular link mechanism.
FIG. 9 is a diagram illustrating how the magnitude relationship between B and CD affects the link operation. FIG. 8 is an exploded perspective view of the arm structure shown in FIGS. 2 to 6 (an example on the left side as viewed from the rear of the vehicle body). FIG. 9A is a schematic view showing a state where a connection portion of an arm structure is viewed from above. (B) is a schematic diagram showing a state where the connection portion is viewed from above when all the arms are configured by one plate. FIG. 10 is a side view showing only the base lower arm and the distal end lower arm of the loading / unloading device in the state of being stored in the vehicle body, and only these are indicated by solid lines. [Description of Signs] 1 Receiving-table 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 lower arm 14 pin (F 15 tip connecting member 16 tip upper arm 17 pin 18 (E) 18 loading table 101 body 104 chassis ABCD base link mechanism CDEF tip link mechanism

Claims (1)

Claims: 1. A left and right pair of arms are provided on a vehicle body as an arm structure of a loading tray elevating device for storing, deploying and lifting and lowering a loading tray,
Each arm structure includes a base upper arm and a base lower arm rotatable within a predetermined range around a pair of upper and lower fulcrums A and B provided on the vehicle body side, and an action point C on each rotation end side of these arms. And a base connecting member connected between D and
A base link mechanism forming a rectangular link having four vertices of A, B, C and D; and a base link mechanism rotatable within a predetermined range around the action points C and D, respectively. The C, D, E and F are connected to each other by a foldable distal end upper arm and a distal end lower arm, and a distal end connecting member connected between action points E and F on the respective rotating end sides of these arms.
A tip link mechanism that constitutes a quadrangular link having an apex and supports the receiving table at the action point E or F side, wherein the base upper arm and the tip upper arm are a set of an upper arm and a base lower. When the arm and the distal end lower arm are a pair of lower arms, the common name of the base upper arm and the lower base arm is the base arm, and the common name of the distal upper arm and the lower end of the arm is the distal end arm, In at least one of the upper arm and the lower arm, one of the base arm and the tip arm is formed of two plates, and the other is a single plate structure connected between the ends of the two plates. Arm structure of the loading / unloading device.