JPH0520903U - Caster - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a caster capable of switching the traveling platform between forward and backward movement without impairing the stability in the traveling direction of the traveling platform. [Structure] A caster 10 is a vertical shaft 12 which is vertically attached to a lower portion of a traveling base 32, and is rotatably supported below the vertical shaft 12. The wheel 16 rotates while changing its direction. Then, the rotation shaft 16a of the wheel 16
Are movable in the horizontal radial direction of the wheel 16 with respect to the vertical shaft 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a caster attached to a traveling platform.

[0002]

[Prior Art]

 For example, casters are often arranged in the front part of a traveling platform in which two driving wheels are arranged on the left and right sides of the rear part. The caster is composed of a vertical shaft that is vertically mounted on the traveling platform, and wheels that are rotatably supported below the vertical shaft and that can turn around the vertical shaft. However, the position of the wheel rotation axis is appropriately offset from the axis of the vertical axis. For this reason, when the traveling platform attempts to turn using the differential of the two drive wheels, the wheels follow the movement of the traveling platform with the rotation axis of the wheel positioned behind the vertical axis. Then rotate while changing its direction. As a result, the traveling platform can smoothly turn.

[0003]

[Problems to be solved by the device]

 However, the wheels of such casters need to be reversed when the platform switches between forward and reverse. That is, the wheels are temporarily turned to the side of the traveling platform. Therefore, there is a problem that the traveling direction of the traveling platform is not stable from the beginning of the forward-reverse switching until the wheels are completely reversed. In particular, in the traveling platform having the casters arranged in the front portion as described above, the stability in the traveling direction of the traveling platform is likely to be greatly degraded when switching from reverse to forward.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a caster capable of switching the traveling platform between forward and backward movement without impairing the stability of the traveling platform in the traveling direction. .

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the caster of the present invention is configured such that the rotation axis of the wheel is movable in the horizontal radial direction of the wheel with respect to the vertical axis. It should be noted that such casters may be provided with a biasing means for biasing the rotation axis of the wheel to be positioned directly below the vertical axis.

[0006]

[Action]

 In such a caster, when the traveling platform switches between forward and backward movements, the rotating shaft of the wheel can move rearward of the traveling direction of the traveling platform with respect to the vertical axis without reversing the direction of the wheel. Therefore, the traveling platform can travel stably from the beginning of switching. If the urging means is provided, the rotation axis of the wheel is returned to a position just below the vertical axis when the traveling platform is stopped. Therefore, when switching between forward and backward, the above-described movement of the rotating shaft with respect to the vertical axis is quickly performed.

[0007]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, an aerial work vehicle 30 including the caster 10 according to the present invention will be described with reference to FIG. The aerial work vehicle 30 is provided with an elevating post 33 in front of a traveling carriage 32 (traveling carriage) 32 that can travel freely. The elevating post 33 includes a lower post member 33a that is detachably attached to the frame 32a of the traveling carriage 32, and an upper post member 33b that is extendably attached to the lower post member 33a. The expansion and contraction of the upper post member 33b is performed by using the operation of the winch 35 attached near the lower end of the lower post member 33a. A board 34 is horizontally attached to the lower end of the upper post member 33b. The worker M on the board 34 can move to an arbitrary height through traveling of the traveling carriage 32 and expansion / contraction of the elevating post 33.

The traveling vehicle 32 is provided with drive wheels 32r, 32r on the left and right outer sides of the rear portion of the frame 32a (however, only the right drive wheel 32r is shown in the drawing). The drive wheels 32r are independently driven by drive motors 32m and 32m (however, only the drive motor 32m on the right side is shown in the figure) attached to the inner right and left of the rear portion of the frame 32a. Therefore, the traveling vehicle 32 goes straight forward or backward by rotating both drive wheels 32r, 32r at a constant speed, and if a difference in rotation is provided between the drive wheels 32r, 32r, the drive wheel 32r on the low rotation side is provided. It makes a turning drive with the inner ring.

Further, the casters 10 are attached to the left and right sides of the front portion of the frame 32a. Hereinafter, the caster 10 will be described in detail with reference to FIGS. 1 and 2. The caster 10 includes a cylindrical mounting body 11 that is mounted on the frame 32a while extending vertically. The vertical shaft 12 is inserted into the cylindrical hole of the mounting body 11. At the lower end of the vertical shaft 12, a disk portion 12a that extends horizontally is formed. The vertical shaft 12 is formed by a bearing 13 arranged between the disk portion 12a and the lower end of the mounting body 11 and a bush 14 arranged between the upper side surface of the vertical shaft 12 and the upper inner surface of the mounting body 11. , Is supported so as to be rotatable around the axis of the vertical shaft 12. A rail 15 is formed on the vertical shaft 12 below the disk portion 12a. The rail 15 is formed in a rectangular tube shape extending in the horizontal direction, and an opening 15a extending in the longitudinal direction is formed in the central portion of the bottom surface thereof.

A wheel 16 rotatably supported by a support member 17 is arranged below the rail 15. The support member 17 has a pair of support portions 17a, 17a each formed in an inverted triangular plate shape and arranged in parallel with each other. The support member 17 is arranged with respect to the wheel 16 so as to sandwich the wheel 16 from above by the support portions 17a and 17a, and supports the rotating shaft 16a of the wheel 16. A lower end of a slider 18 having a T-shaped cross section is attached to the upper surface of the support member 17. The slider 18 is mounted in the rail 15 with its lower end protruding from the opening 15a of the rail 15 below the rail 15. The slider 18 is slidable along the rail 15. In this way, the wheel 16 is movably suspended in the horizontal radial direction of the wheel 16 with respect to the vertical shaft 12 (hereinafter, this direction is referred to as the front-rear direction). Hereinafter, the wheel 16, the support member 17, and the slider 18 are collectively referred to as a suspension portion of the caster 10.

After the slider 18 is attached, the front and rear ends of the rail 15 are sealed by the sealing members 19 and 19. This prevents the hanging portion from falling off the rail 15. However, springs (biasing means) 21 and 21 are mounted between the front and rear end surfaces of the slider 18 mounted in the rail 15 and the inner side surfaces of the sealing members 19 and 19. These springs 21 and 21 urge the suspension part so that the rotation shaft 16a of the wheel 16 is located directly below the vertical shaft 12.

In the caster 10 configured in this way, when the traveling vehicle 32 travels backward (travels to the left in FIGS. 1 and 3), the suspending portion causes friction that acts on the ground contact portion of the wheel 16. It is pulled by force and slides forward (to the right of the vertical axis 12). Therefore, the position of the rotating shaft 16a of the wheel 16 is offset forward from the axis of the vertical shaft 12 (see A in FIG. 1). Therefore, when the traveling carriage 32 turns while moving backward, the wheels 16 follow the movement of the traveling carriage 32 while rotating around the vertical axis 12 while changing the direction thereof, so that the traveling carriage 12 moves smoothly. Let it run.

When the traveling carriage 32 stops after moving backward in this manner, the suspension portion is returned to a position right below the vertical shaft 12 by the urging force of the front-side spring 21 (completely by the ground contact friction force acting on the wheels 16). It doesn't mean that it will return right below). Immediately after that, when the traveling carriage 32 starts to move forward, the suspension portion slides backward with respect to the vertical axis 12 this time. Therefore, the position of the rotary shaft 16a of the wheel 16 is offset rearward from the axis of the vertical shaft 12 (see B in FIG. 1). Therefore, the traveling carriage 12 can travel smoothly even when the traveling carriage 32 turns while moving forward.

In this way, when the traveling carriage 12 is switched between forward and backward, the rotary shaft 16a of the wheel 16 of the caster 10 is arranged rearward or forward with respect to the axis of the vertical shaft 12 even if the direction of the wheel 16 is not reversed. Is automatically offset to. Therefore, the traveling direction of the traveling vehicle 32 can be stabilized from the beginning of switching.

In the above embodiment, the aerial work vehicle 30 is described as an example, but the vehicle (running platform) to which the caster according to the present invention is attached is not limited to this.

[0016]

[Effect of the device]

 As described above, in the caster of the present invention, when the traveling platform travels, the rotation axis of the wheel is automatically offset rearward in the traveling direction with respect to the axis of the vertical axis. Therefore, when the traveling platform is switched between the forward and backward directions, the offset direction is switched without reversing the direction of the wheels. Therefore, the traveling direction of the traveling platform can be stabilized from the beginning of switching between forward and backward movements, which is extremely effective in improving the traveling performance of the traveling platform. In addition, if a biasing means is provided, the wheels are returned to a position just below the vertical axis when the platform is stopped. Therefore, it is possible to quickly switch the offset direction as described above.

[Brief description of drawings]

FIG. 1 is a side view of a caster according to the present invention.

FIG. 2 is a sectional view taken along line II in FIG.

FIG. 3 is a side view of an aerial work vehicle including the casters.

[Explanation of symbols]

 10 Casters 12 Vertical Axis 15 Rails 16 Wheels 16a Rotating Axis 17 Supporting Member 18 Slider 20 Spring 32 Traveling Cart

Claims (2)

[Scope of utility model registration request] 1. A vertical shaft vertically mounted on a traveling base, and a wheel rotatably supported below the vertical shaft, the wheel following the traveling movement of the traveling base. A caster that rotates while changing its direction around the center, wherein the rotation axis of the wheel is movable in the horizontal radial direction of the wheel with respect to the vertical axis. 2. The caster according to claim 1, further comprising an urging means for urging the rotating shaft of the wheel so as to be positioned directly below the vertical shaft.