JP2006188137A - Caster wheel support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive caster wheel support device of which axle does not stop beneath a perpendicular shaft. <P>SOLUTION: The caster wheel support device S has a guide device 4 for slidably guiding a support body 2 between one end 41 and the other end 42 distant in a horizontal direction, and a rotating device 5 which rotatably supports the guide device 4. Even if the axle 3 stops beneath the perpendicular shaft 1, a reaction of the traveling resistance of a caster wheel C which the axle 3 receives right before the stopping generates a moment M for rotating the axle 3 to a horizontal shaft 51 in an opposite direction to a traveling direction of an undercarriage H, therefore an inclination posture of a guide rail 43 is changed to such a posture that the one end 41 becomes lower than the other end 42, thus moving the caster wheel C toward the other end 42 of the guide rail 43. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a caster wheel support device that can be applied to a caster of an automatic guided vehicle, for example.

In an automatic guided vehicle including a drive wheel, a steering wheel, and a caster, a chassis is supported on a road surface by the plurality of wheels. The caster is obtained by attaching a caster wheel having an axle to a chassis via a caster wheel support device described below. The caster wheel support device supports the above axle on a bracket (support) that can turn around a kingpin (vertical axis). And since the position of the axle is different in the horizontal direction with respect to the kingpin, the caster wheel can turn around the kingpin together with the axle.

Therefore, according to the caster wheel support device described above, the caster wheel changes its direction according to the traveling direction of the chassis. Specifically, when the axle receives a reaction force of the running resistance while the chassis is moving forward, the bracket turns around the kingpin so that the caster wheel faces in a direction of retreating with respect to the kingpin. On the other hand, in the process of moving the chassis forward, the bracket turns around the kingpin so that the caster wheel faces in the direction of retreating with respect to the kingpin. For example, when the chassis that has been moving forward turns backward, the caster wheel will turn about 180 ° around the kingpin.

Such turning causes the chassis to shake. Therefore, the casters described in the following patent documents are provided with a slide mechanism composed of a rack and a pinion that linearly moves the axle in the front-rear direction. As a result, the caster wheel recedes straight with respect to the kingpin as the chassis moves forward. On the other hand, the caster wheel moves straight forward with respect to the kingpin as the chassis moves backward. Therefore, when the forwardly moving chassis turns backward, the position of the caster wheel can be changed with respect to the king pin without turning the bracket about 180 ° as described above.
JP 2003-237304 A JP 7-242101 A

However, the axle passes under the kingpin as the caster wheel that has been retracted relative to the kingpin moves straight forward. At this time, if the chassis is caused to travel sideways in a direction orthogonal to the front-rear direction, the caster wheel cannot turn around the king pin, and therefore cannot follow the traveling operation of the chassis.

This causes a problem that the chassis travels sideways while dragging the caster wheel.
In addition, it is conceivable that the position of the axle is fixed by electromagnetic operation of a solenoid or the like so that the axle does not pass directly below the vertical axis. There is a problem that the manufacturing cost of the entire transport vehicle increases.

An object of the present invention is to provide a caster wheel support device at a low cost in which an axle does not stop directly below a vertical axis.

The present invention relates to a caster wheel support device in which a support for supporting an axle can turn around a vertical axis, and has a first end and a second end separated in a horizontal direction. Guide means for movably guiding the support and rotation means for rotatably supporting the guide means so that one end and the other end of the guide can be raised and lowered relative to each other.

Further, in the caster wheel support device according to the present invention, the fulcrum for rotating the guide means so that the one end and the other end thereof are moved up and down mutually is at a position that bisects between the one end and the other end of the guide means. It is characterized by corresponding.

According to the caster wheel support device of the present invention, the support body that supports the axle such as the caster wheel can be movably guided between the one end and the other end of the guide means that are separated in the horizontal direction. When retreating, the support body, together with the axle that receives the reaction force of running resistance such as caster wheels,
Move straight toward the opposite side of the chassis. In this process, the axle passes directly under the vertical axis, but the guide means is rotatably supported by the turning means so that one end and the other end of the guide means can be moved up and down with each other. Even if the chassis changes direction or stops when it is located directly below the vertical axis, the following operation can be achieved.

That is, the reaction force of the running resistance received by the axle generates a moment for turning the axle in the direction opposite to the running direction of the chassis with respect to the fulcrum where the guide means turns. For this reason, even if the axle is located directly below the vertical axis, immediately before that, the guide means assumes an inclined posture in which the height of one end or the other end is changed by the moment. For example, if the other end of the guide means is rearward with respect to the traveling direction, the guide means is inclined so that the other end is higher than the one end. Further, since the axle receives the load of the chassis via the guide means, the axle further moves to the other end of the guide means while the guide means is maintained in the above-described inclined posture by the reaction force of this load.

Regardless of the timing at which the chassis changes direction or stops, the axle position can be changed in the horizontal direction with respect to the vertical axis, so that the chassis changes direction or stops when the axle passes directly below the vertical axis. Even if the vehicle is run sideways in the direction perpendicular to the front-rear direction, the axle can turn around the vertical axis along with the support.

Accordingly, since the caster wheels and the like can turn in accordance with the traveling direction of the chassis together with the axle, the conventional problem that the chassis travels sideways while dragging the caster wheels or the like can be solved. Moreover, since it does not depend on the electromagnetic operation of a solenoid or the like, no wiring or the like is necessary, and the entire manufacturing cost of the automatic guided vehicle can be suppressed.

Further, according to the caster wheel support device of the present invention, the fulcrum where the guide means rotates so that the one end and the other end of the guide means move up and down mutually is at a position that bisects between the one end and the other end of the guide means. Therefore, the above-described effects can be equally achieved in either case where the forwardly moving chassis turns backward or when the backwardly moved chassis turns forward.

First, a caster wheel support device according to an embodiment of the present invention will be described. As shown in FIGS. 1 (a) and 1 (b), the automatic guided vehicle V is provided with two wheels W serving as driving wheels and steering wheels on the front and rear sides of one side of the chassis H, respectively. Two caster wheels C are provided near the center of the section. The caster wheel C is attached to the chassis H through a caster wheel support device described below. The virtual circles in the figure represent the turning ranges of the wheels W and caster wheels C, respectively.

FIG. 2 shows a caster wheel support device S configured so that the support 2 can turn with the axle 3 around the vertical axis 1. The caster wheel support device S has one end 41 that is horizontally spaced.
And the other end 42 are provided with guiding means 4 for guiding the support 2 and rotating means 5 for rotatably supporting the guiding means 4. Arrows F and R in the figure indicate the forward direction in which the chassis H of the automatic guided vehicle V moves forward,
And the back direction which each reverses is pointed out, respectively, and the chassis H is maintaining the horizontal attitude | position.

The guide means 4 is such that a slider 44 having the support 2 fixed thereto is slidably engaged with a guide rail 43 extending in a substantially horizontal direction. One end 41 and the other end 42 of the guide rail 43 serve as a stopper that prevents the slider 44 from running away. In the guide rail 43, the upper edge between the one end 41 and the other end 42 is connected to the vertical shaft 1 made of a pin via the rotary joint 6. The rotary joint 6 freely turns the guide rail 43 with the vertical shaft 1 as a fulcrum, but is provided with a thrust bearing not shown in the figure in order to hold the guide rail 43.

The rotating means 5 is connected to a horizontal shaft 51 composed of pins extending in a horizontal direction orthogonal to the front-rear direction, a fixing member 52 that fixes the horizontal shaft 51 to the lower surface of the chassis H, and the rotary joint 6 connected to the horizontal shaft 51. The swinging member 53 is provided. When the swinging member 53 swings back and forth with the horizontal shaft 51 as a fulcrum, one end 41 and the other end 42 of the entire guide means 4 are moved up and down. That is, the guide rail 43
Will move like a so-called seesaw.

According to the caster wheel support device S described above, as shown in FIG. 2, in the process of moving the chassis H in the direction of arrow F, the axle 3 causes the reaction force of the running resistance of the caster wheel C to move in the direction of arrow R. Accordingly, the support body 2 moves along the guide rail 43 in the direction of arrow R together with the axle 3, and the slider 44 reaches one end 41 of the guide rail 43. Alternatively, when the slider 44 is positioned in advance near the one end 41 of the guide rail 43, the support body 2 does not move along the guide rail 43. Further, since the axle 3 receives the load of the chassis H through the guide rail 43, one end 41 of the guide rail 43 is pushed upward, and the guide rail 43 is inclined. In this state, a rotation stopper not shown in the figure hits an appropriate position of the swinging member 53, and the inclination angle of the guide rail 43 is defined to be about 5 °.

Subsequently, when the traveling direction of the chassis H changes from forward to backward, the reaction force of the traveling resistance received by the axle 3 also changes in the direction of the arrow F. Therefore, as shown in FIG. Move along the guide rail 43 in the direction. In this process, the axle 3 passes directly below the vertical shaft 1, but the reaction force of the running resistance received by the axle 3 causes the axle 3 to move against the horizontal shaft 51 that serves as a fulcrum for turning the guide rail 43. A moment M is generated to turn the chassis H in the direction opposite to the traveling direction. For this reason, with the direction change or stop of the chassis H,
Even if the axle 3 stops just below the vertical shaft 1, just before that, the guide rail 43
Changes to an inclined posture in which the other end 42 is higher than the one end 41 by the moment M.

Further, the axle 3 moves to the other end 42 of the guide rail 43 while receiving the load of the chassis H through the guide rail 43, and reaches the state shown in FIG. As is clear from the figure, since the position of the axle 3 is different in the horizontal direction with respect to the vertical shaft 1, in this state, even if the chassis H is run sideways in the direction orthogonal to the front-rear direction, the support 2 At the same time, the caster wheel C is the vertical axis 1
Can be turned around the fulcrum. Accordingly, since the caster wheel C can turn along with the axle 3 in accordance with the traveling direction of the chassis H, the chassis H does not travel sideways while dragging the caster wheel C as in the prior art.

Next, examples of the present invention will be described. The same members as those already described are denoted by the same reference numerals, and detailed description or illustration thereof is omitted.

As shown in FIGS. 5 and 6, the rotating means 5 is formed by welding a fixing member 52 that supports the horizontal shaft 51 to a base plate 54 that is fixed to the lower surface of the chassis H by bolts, and the swinging member is attached to the horizontal shaft 51. 5
3 is rotatably supported. The swinging member 53 projects a pair of rotation stoppers 55 extending in the front-rear direction. When the inclination angle of the guide rail 43 reaches about 5 °, the height adjustment of the pair of rotation stoppers 55 depending on the base plate 54 is performed. It hits the bolt 56. A pair of caster wheels C are attached to both ends of the axle 3, and the pair of caster wheels C are supported by one support body 2.

In addition, the description of the operation related to the caster wheel support device S has been given of the case where the forward moving chassis H turns backward. However, when the backward moving vehicle body H turns forward, the caster wheel support device S operates as described above. Do the opposite.

That is, the reaction force of the running resistance received by the axle 3 in the process of moving the chassis H generates a moment in the direction opposite to the moment M described above, so that even if the axle 3 is located directly below the vertical axis 1, The guide means 4 has one end 41 and the other end 42 by a moment in a direction opposite to the moment M.
A higher inclined posture. For example, if the other end 42 of the guide unit 4 is located behind the traveling direction, the guide unit 4 is inclined so that the other end 42 is higher than the one end 41. Further, since the axle 3 receives the load of the chassis H via the guide means 4, the axle 3 further reaches one end 41 of the guide means 4 while the guide means 4 is maintained in the above-described inclined posture by the reaction force of this load. Moving.

Further, the horizontal shaft 51, which is a fulcrum for turning the guide rail 43, corresponds to a position directly above the midpoint m that bisects the distance between the one end 41 and the other end 42 of the guide rail 43. There is substantially no difference in timing between the operation when H turns backward and the operation when the moving chassis H turns forward. Therefore, the caster wheel support device S can achieve the desired effect regardless of the traveling direction of the automatic guided vehicle V.

It should be noted that the present invention can be implemented in a mode in which various improvements, modifications, or variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. For example, in the above description, the rotation means 5, the rotary joint 6, and the guide means 4 are arranged in order from the top, but the rotation means 5 may be arranged below the rotary joint 6. In other words, even when the rotation means 5 is arranged between the guide means 4 and the rotary joint 6, the above-described operation can be realized.

The caster wheel support device according to the present invention can be applied not only to the automatic guided vehicle but also to a caster of a cargo handling vehicle that loads heavy objects.

(A) is a top view of the automatic guided vehicle to which the caster wheel support apparatus which concerns on embodiment of this invention is applied, (b) is the side view. The side view which illustrates the initial stage of operation | movement of the caster wheel support apparatus which concerns on embodiment of this invention. The side view which illustrates the process of the operation | movement of the caster wheel support apparatus which concerns on embodiment of this invention. The side view which illustrates the result of operation of the caster wheel support device concerning the embodiment of the present invention. The side view of the caster wheel support device concerning Example 1 of the present invention. The front view of the caster wheel support apparatus which concerns on Example 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Vertical axis | shaft 2: Support body 3: Axle 4: Guide means 5: Turning means 6: Rotary joint 41: One end 42: Other end 51: Horizontal axis C: Caster wheel H: Chassis S: Caster wheel support device

Claims (2)

A caster wheel support device in which a support body supporting an axle can turn around a vertical axis,
A guide means having one end and the other end separated in a horizontal direction, and movably guiding the support body between the one end and the other end;
A caster wheel support device, comprising: a pivot unit that pivotably supports the guide unit so that one end and the other end of the guide unit can be moved up and down. The fulcrum that the guide means rotates so as to move up and down one end and the other end of the guide means corresponds to a position that bisects between the one end and the other end of the guide means. Caster wheel support device.

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