JP2003025805A - Brake structure for caster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake structure for a caster capable of obtaining a braking force by only a pedal operation of contacting a brake shoe to a wheel and using the rotation of the wheel after that. SOLUTION: This brake structure is characterized in that the brake shoe is pivotally mounted in an upper or a lower part of a tread surface of the wheel, the brake shoe is pivotally moved by interlocked with the rotation of the wheel, when the brake surface of the brake shoe contacts with a braking counter-surface of the wheel, and the length from the pivot point of the brake shoe to the brake surface is set to be getting longer as the rotation angle of the wheel becomes larger from the position where the brake shoe contacts therewith.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caster braking structure capable of reducing an operating force during braking.

[0002]

2. Description of the Related Art In order to brake the rotation of wheels of casters, conventionally, a structure has been adopted in which the wheels are pressed by brake shoes. That is, the operation pedal is moved to displace the brake shoe via a transmission mechanism such as a cam or a link, the wheel is pressed by the brake shoe, and the friction between the brake shoe and the wheel is used for braking. Therefore, in order to increase the braking force, it is necessary to increase the pedal operation force, and a large force is required for pedal operation, which makes operation difficult. Further, after the pedal operation is completed, only a constant braking force can be obtained because the brake shoe and the wheel are in contact with each other with a constant pressing force for braking. It is desired that the pedal is lightly operated, but the braking force is required to be strong, and at present, the two are contradictory phenomena. In addition, since the tread surface of the wheel is in contact with the floor surface when the caster is in use, the friction with the brake shoes will be reduced due to dust, dirt, wear on the tread surface of the wheel, etc. even if the pressing amount (force) is constant. There is also a possibility that it may decrease and the original braking force may not be maintained.

[0003]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances, and its main problem is to complete the braking operation by pedaling only the brake shoe to contact the wheel, and then the wheel. It is an object of the present invention to provide a caster braking structure capable of automatically increasing the braking force by utilizing the rotation when the wheel rotates.

[0004]

In order to achieve the above object, in the invention of claim 1, the pedal is operated to bring the braking surface of the wheel into contact with the braking surface of the wheel so that the wheel rotates. Then, technical measures are taken such that the brake shoes work together to displace the brake shoes in a direction in which the braking force is increased and automatically increase the braking force to the wheels. Further, in the invention of claim 2, the brake shoe is pivotally mounted above or below the tread surface of the wheel, and when the braking surface of the brake shoe comes into contact with the braked surface of the wheel, the brake shoe interlocks with the rotation of the wheel. Is configured to pivot, and the length from the pivot point of the brake shoe to the braking surface is set to increase as the rotation angle of the wheel increases from the position where the brake shoe contacts. Taking technical measures. Further, in the invention of claim 3, the brake shoe is pivotally mounted at a position eccentric from the center of the wheel, and when the braking surface of the brake shoe comes into contact with the surface to be braked of the wheel, the brake shoe interlocks with the rotation of the wheel. Is provided so that the brake shoe pivots in a direction in which the brake shoe bites into the braked surface of the wheel due to the rotation of the wheel to increase the braking force. According to the invention of claim 4, when the braking surface of the brake shoe comes into contact with the braking surface of the wheel, the braking surface rotates in conjunction with the rotation of the wheel, and the contact area of the braking surface of the brake shoe is the braking force of the wheel. The technical measure is taken so that it is set so as to become wider as the rotation angle of the wheel increases from the position in contact with the surface. Claim 6
In the invention of claim 1, a booster is provided between the wheel and the brake shoe, which is interlocked with the rotational force of the wheel and is largely converted into a force for pressing the brake shoe against the braked surface of the wheel. I am taking steps.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a braking structure for casters of the present invention will be described below with reference to the drawings.
The caster 1 of the first embodiment shown in FIG. 1 includes a mounting board 2, a yoke portion 3 pivotably mounted on the mounting board 2, a wheel 4 pivotally supported by the yoke portion 3, braking or braking. It is composed of a pedal 5 for releasing, a brake arm 7 which is displaced by a known cam 6 by the pedal 5, and a brake shoe 10 pivotally attached to the brake arm 7.

The brake shoe 10 is pivotally mounted on a pivot P1 at a position below the tread surface 9 of the wheel 4. An elastic body 11 (may be a leaf spring, a wire spring, or the like) such as rubber is provided between the brake shoe 10 and the brake arm 7, and the brake shoe 10 serves as a wheel 4.
The tread surface 9 serving as the braked surface is urged in the tangential direction.

Here, when the pedal 5 is brought to the braking position (the solid line position in the figure), the brake arm 7 brakes the shoe 10.
Touches the tread surface 9 of the wheel 4, and the frictional force may be set to such an extent that it can pivot in conjunction with the rotation of the wheel 4. Therefore, the operating force is lighter than the conventional one. When the brake is released, when the pedal 5 is rotated clockwise in the drawing with the pivot point 8 coaxial with the axle as the fulcrum to switch to the brake release position, the brake arm 7 is raised and the brake shoe 10 is moved to the tread of the wheel 4. It is displaced to a position separated from the surface 9 with a gap.

During the braking, the brake shoe 1
Reference numeral 0 is in contact with the tread surface 9, and when the wheel 4 rotates forward or backward, the brake shoe 10 pivots in an interlocking direction with the pivot point of the pivot P1 as a fulcrum, and the tip end side of the brake shoe 10 is tread surface 9. It is displaced in the direction that bites into.

As a result, when the wheel 4 tries to rotate forward or backward, the brake shoe 10 tilts and bites strongly into the tread surface 9 in proportion to the rotation angle thereof, so that the wheel 4 is irrelevant to the manual operation force. A braking force proportional to the rotational force of is automatically obtained. In the present embodiment, since the brake shoe 10 is held in the neutral posture, the braking force acts regardless of whether the wheel 4 rotates in the front or rear direction.

In the braking structure of the caster 1 of the second embodiment shown in FIG. 2, the brake shoe 10 is pivotally attached to the brake arm 7, but the brake shoe 10 is pivoted at a position above the tread surface 9 of the wheel 4. It is pivotally attached at P1. A spring (wire spring) 11 is hooked on the pivot P1 to urge the brake shoe 10 so that it faces the tread surface 9 in its tangential direction. Since other configurations are similar to those of the above-described embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.

The braking structure of the caster 1 of the third embodiment shown in FIG. 3 is a different embodiment in which a block having a substantially fan-shaped cross section is used as the brake shoe 10. In the case of the illustrated example, the basic structure of the caster and the operation pedal are omitted, and the configuration of the brake arm or the like for displacing the brake shoe 10 to the position in contact with the wheel by pedal operation is also omitted.

In this embodiment, the brake shoe 10 is
The brake shoe 10 is pivotally mounted above the tread surface 9 of the wheel 4 by a pivot P2, and when the braking surface of the brake shoe 10 comes into contact with the tread surface 9 that serves as the braked surface of the wheel 4, the brake shoe 10 interlocks with the rotation of the wheel 4. Is configured to be pivotally displaced. Then, as shown in FIG. 3B, the length of the brake shoe 10 from the pivot P2 to the braking surface is such that the length r1 at the central position is the shortest and gradually increases toward the ends, r1 <. It is set symmetrically with respect to the center position as r2 <r3.

Therefore, also in this case, the brake shoe 10
Does not need to be strongly pressed against the tread surface 9, and only needs to be brought into contact with each other in an interlockable manner, so that the pedal operation can be performed with a light operating force. During the braking, the brake shoe 10 is in contact with the tread surface 9, and when the wheel 4 rotates forward or backward, the brake shoe 10 pivots in an interlocking direction with the pivot P2 as a fulcrum, and the brake shoe 10 is braked. The surface gradually becomes longer from the axis P2, and the tread surface 9
I will cut into.

As a result, a large braking force is automatically obtained regardless of the manual operation force. In this embodiment as well, since the brake shoe 10 is held in the neutral posture, the braking force acts even if the wheel 4 rotates in either the front or rear direction.

Next, the braking structure of the caster 1 according to the fourth embodiment shown in FIG. 4 has a structure similar to that of the first embodiment, and the brake shoe 10 is located below the tread surface 9 on the brake arm (not shown). And is pivotally connected by the axis P1. The brake shoe 10 is composed of a lever piece 10b extending from the pivot position, a shoe main body 10a of a rubber block forming a braking surface, and a support piece portion 10c for attaching the shoe main body 10a to the lever piece 10b.

The brake shoe 10 is pressed against the tread surface 9 by a cam or a toggle mechanism during braking.
As a result, the brake shoe 10 pivots in association with the rotating direction of the wheel 4, and the braking surface of the brake shoe 10 bites into the tread surface 9 to increase the braking force.

Next, the braking structure of the caster 1 of the fifth embodiment shown in FIG. 5 has a structure according to the second embodiment, and the brake shoe 10 is located above the tread surface 9 on the brake arm (not shown). And is pivotally connected by the axis P1. Further, the braking surface of the brake shoe 10 is configured to come into contact with the inner peripheral surface 9 ′ of the step portion having a smaller diameter inside the tread surface 9 of the wheel 4. The structure of the brake shoe 10 is similar to that of the fourth embodiment.

During braking, the brake shoe 10 is pressed upward against the inner peripheral surface 9'by a cam or a toggle mechanism. As a result, the break shoe 10 pivots in association with the rotating direction of the wheel 4, and the braking surface of the brake shoe 10 bites into the inner peripheral surface 9 ′ to increase the braking force.

In the caster braking structure of the sixth embodiment shown in FIG. 6, when the braking surface of the brake shoe 10 comes into contact with the tread surface 9 serving as the braked surface of the wheel 4, it rotates in conjunction with the rotation of the wheel 4. It is configured. That is, the brake shoe 10 has a roller shape, and the rotation shaft P2 is provided on the wheel 4.
Is rotatably supported by a cam and a toggle mechanism or the like so as to be capable of interlockingly contacting the tread surface 9 via a brake arm or the like (not shown).

In the brake shoe 10, the contact area of the braking surface 10a of the brake shoe gradually increases as the rotation angle of the wheel increases from the position where the braking surface 10a of the brake shoe contacts the surface to be braked of the wheel. It is set in a substantially triangular shape when viewed from the top so that the height increases. As a result, the rotation of the wheels 4 causes the break shoe 10 to rotate,
The contact area of the braking surface of the brake shoe 10 with the tread surface 9 is increased, and the braking force can be increased.

Next, in the caster braking structure of the seventh embodiment shown in FIG. 7, between the wheel 4 and the brake shoe 10,
The brake shoe 1 is displaced in association with the rotational force of the wheels 4
It has a configuration in which a booster mechanism 20 that greatly converts 0 into a force for pressing the tread surface 9 of the wheel 4 is provided. That is,
A small-diameter gear 21 is coaxially fixed to the wheel 4 at the center. On the other hand, one end 22a of a substantially C-shaped actuating arm 22 is pivotally attached to the brake shoe 10 by a pivot P3, and a tooth portion 22c is formed inside the other end 22b to form the gear 2
It meshes with 1.

A guide link 23 is provided between the shaft center of the gear 21 and the pivot P3 position of the brake shoe 10 to guide the displacement of the operating arm 22. Therefore, when the wheel further rotates in the direction a in the figure from the pedal operation position where the brake shoe 10 comes into contact with the tread surface 9, the rotation of the gear 21 causes the operation arm 22 to be screwed in the direction b so that the screw arm is screwed downward to pivot the shaft. Displace P3 in the pulling direction.

The pivot P3 is strongly pushed in the c direction, which is guided by the elongated hole 24 of the guide link 23 and bites into the tread surface 9, so that the brake shoe 10 is strongly pressed against the tread surface 9 and the braking force can be increased. . When the brake is released, the working arm 22 is disengaged from the gear 21 in this embodiment, and the tooth portion 22c is used in this embodiment.
The other end 22b formed with is pivotally attached by a pivot P4 so as to tilt in the direction d in the figure, and is held at a virtual line position away from the gear 21 when the caster is running, and is not shown during braking. The other end 22b operates the gear 2 by operating the braking operation unit of
1 is displaced and held at a solid line position where it meshes with 1. The booster mechanism is not limited to the above-described embodiment, and any mechanism that converts force so as to increase the pressing force of the brake shoe depending on the rotation (angle) of the wheel may be used.

In each of the above embodiments, the braking surface of the wheel is
The location is not limited to the tread surface or the inner peripheral surface formed on the concentric step portion of the wheel, and may be any location provided integrally with the wheel and rotating integrally. Further, a part of the configuration disclosed in the above embodiment may be replaced or used in combination. In addition, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[0025]

According to the present invention, the braking operation is completed by the pedal operation only by bringing the brake shoe into contact with the wheel, so that the braking operation can be performed by a light operation without requiring a force. When the wheels try to rotate after the braking operation, the braking force can be strengthened by automatically displacing the brake shoe in the direction in which the frictional force is strengthened by using the force generated by the rotation, so that a large operating force is required. It is possible to apply a strong braking force to the wheels. Therefore, even if dust or dirt is attached to the braking surface of the brake shoe, or even if the surface to be braked such as the tread surface of the wheel is worn away due to wear or the like, sufficient braking force can be exerted.

[Brief description of drawings]

FIG. 1A is a side view of a braking structure for a caster according to a first embodiment, and FIG. 1B is a sectional view of a brake shoe portion.

2A is a side view of a braking structure for a caster according to a second embodiment, and FIG. 2B is a sectional view of a brake shoe portion.

FIG. 3A is a side view of a braking structure for a caster according to a third embodiment, and FIG. 3B is an enlarged view of a brake shoe portion.

FIG. 4 is a side view of a braking structure for a caster according to a fourth embodiment.

FIG. 5 is a side view of a caster braking structure according to a fifth embodiment.

FIG. 6 is a perspective view of a caster braking structure according to a sixth embodiment.

FIG. 7 is a side view of a braking structure for a caster according to a seventh embodiment.

[Explanation of symbols]

1 caster 2 Mounting board 3 Yoke part Four wheels 5 pedals 6 cams 7 Brake arm 9 tread surface 10 brake shoes 11 elastic body 20 booster

Claims (5)

[Claims] 1. A pedal operation causes a braking surface of a wheel to interlock with a braking surface of a wheel, and when the wheel is about to rotate, the brake shoe interlocks to displace the brake shoe in a direction in which a braking force is increased. A caster braking structure characterized by automatically increasing the braking force applied to the wheels. 2. A brake shoe is pivotally mounted above or below a tread surface of a wheel, and when the braking surface of the brake shoe contacts a braked surface of the wheel, the brake shoe pivots in conjunction with rotation of the wheel. And the length from the pivot point of the brake shoe to the braking surface is set to increase as the rotation angle of the wheel increases from the position where the brake shoe contacts. The caster braking structure according to Item 1. 3. The brake shoe is pivotally mounted at a position eccentric from the center of the wheel, and when the braking surface of the brake shoe contacts the braked surface of the wheel, the brake shoe pivots in conjunction with the rotation of the wheel. The caster braking structure according to claim 1, wherein the brake shoe is pivoted in a direction in which the brake shoe bites into a braked surface of the wheel due to rotation of the wheel to increase a braking force. 4. When the braking surface of the brake shoe comes into contact with the braking surface of the wheel, the braking surface rotates in conjunction with the rotation of the wheel, and the contact area of the braking surface of the brake shoe is the braking surface of the wheel. The caster braking structure according to claim 1, wherein the braking structure is set to become wider as the rotation angle of the wheel increases from the contact position. 5. A booster is provided between the wheel and the brake shoe, the booster being displaced in association with the rotational force of the wheel and largely converted into a force for pressing the brake shoe against the braked surface of the wheel. The caster braking structure according to claim 1.