Patent Description:
As disclosed in PTL <NUM>, a brake device for a caster is available, in which a brake shoe is disposed at a frame (fork), and an operation body is inserted and fitted in a hole drilled in the top panel of a frame, and the operation body is operated synchronously via a transfer means constituted of a cam, a link rod, and the like connected to a brake operation lever.

Further, <CIT> discloses a braking device for shopping trolleys and everything that is handled manually using means that use wheels with fixed or swivel support, wherein the braking device has means of a lever for a braking trolley. The braking device is u-shaped, wherein the final part has one or more protruding tooth, which could be lowered to contact one or more wheel locking tooth causing total blocking of the wheel. The wheel locking tooth has an inclined surface at an acute angle with respect to a line connecting an outer circumferential end of the wheel locking tooth and a center of the wheel is formed at an end face of the wheel locking tooth that comes in contact with the protruding tooth.

<CIT> discloses a manually movable transport carriage suitable for transport on moving walkways and escalators, comprising a pushing device and the braking device being connected to each other via brake linkages, wherein the rear wheels having stop surfaces and the braking device having projections intended to engage the stop surfaces, wherein, when the braking device is not actuated, reverse rotation of the rear wheels is prevented and forward rotation is possible against the action of the braking force applied by the braking device. Further, a stop surface is arranged towards the horizontal axis, i.e. radially. In addition, the projection is spring-loaded.

<CIT> discloses a brake system for running stroller comprising a synchronizer to enable the brake system simultaneously braking to rear wheels with one hand lever and an arrester device to arrest the wheel to completely stop the roller, wherein the hand lever affects a first steel wire from the synchronizer which affects a pair of second steel wires, wherein the steel wires are secured within a disk which is movably disposed within synchronizer. The arrester device has an arrester ring with a plurality of radial arrester plaster spacedly formed on the arrester ring, wherein a check rod is insertable into a gap between the arrester a plates to hinder the wheels from rotation via a tread plate.

Incidentally, in the brake device disclosed in PTL <NUM>, the brake shoe is brought into contact with the circumferential surface of a roller so that the roller is braked by frictional resistance caused by the contact. For this reason, the braking effect may be reduced, and the circumferential surface of the roller may be damaged.

The present invention was completed in view of the problem in the background art. It is an object of the present invention to provide a brake device for a caster, which has a simple structure, provides reliable braking, has no risk of damaging the circumferential surface of a roller, and has high durability.

According to the present invention, a brake device for a caster comprises a plurality of projecting parts formed concentrically on opposite side-surfaces of a roller, and levers set across the roller at opposite side-panels of a fork so as to be opposed to the projecting parts, and a claw formed at a tip of each of the levers so as to be opposed to each of the projecting parts.

According to the invention, the levers are operated, so that the claw is engaged with a concave part formed between the projecting parts, to lock the rotation of the roller, wherein a cable coupling unit having a slide body is set at an intermediate point of a cable, and the cable on an operation lever side and the cable on the lever side are coupled via the slide body, wherein the cable coupling unit comprises at least one compression spring, wherein at least one tension spring is operatively interposed between the cable and the slide body and/or the cable and the lever.

With the brake device for a caster in accordance with the present invention, the claw of the lever is engaged with the projecting part formed at the side-surface of the roller, thereby applying brake to the roller. Accordingly, a reliable braking effect can be obtained, and the circumferential surface of the roller will not be damaged. With the brake device for a caster in accordance with the present invention, in addition to the effect, when release cannot be performed with ease due to biting of the claw of the lever into the concave part between the projecting parts, or the like, the at least one interposed tension spring is stretched, which reduces the burden on the cable. In addition, also subsequently, the spring is urged on the lever in the direction of release, which performs the action of releasing the brake. With the brake device for a caster in accordance with the present invention, in addition to the effect, a plurality of the cables of the operation levers are coupled with the slide body, and a plurality of cables to the levers of the casters are coupled with the slide body. As a result, it is possible to transfer the power of the selected operation lever to each caster.

For this reason, the durability is also high, and further the structure is simple.

With the brake device for a caster preferably in addition to the effect, the claw of the lever is engaged with the inclined surface of the projecting part, and hence the engagement becomes firm, resulting in further enhancement of the braking effect.

With the brake device for a caster may in addition to the effect, even when the roller rotates, the cable will not be twisted.

Below, a brake device for a caster in accordance with the present invention will be described in details by way of embodiments shown in the accompanying drawings.

<FIG> shows a basket trolley <NUM>. The basket trolley <NUM> has a rectangular bottom panel <NUM>. Then, a fence <NUM> is vertically arranged in the periphery of the bottom panel <NUM>. One side of the fence <NUM> includes double doors 3a.

Casters <NUM> are set at the four corners of the bottom panel <NUM>. Out of these, two casters are rotatable casters 4a, and the residual two casters are fixed casters 4b. As shown in <FIG>, each rotatable caster 4a includes a fork <NUM> in a generally U shape including a top panel 5a and side-panels 5b bent in a direction at right angles from the opposite ends thereof. A shaft <NUM> is laid across both the side-panels 5b, 5b of the fork <NUM> in an inserted manner, and a roller <NUM> is rotatably held by the shaft <NUM>. At the lower surface of the bottom panel <NUM> of the basket trolley <NUM>, a mount stand <NUM> is fixedly set as shown in <FIG>. The top panel 5a of the fork <NUM> is rotatably set at the mount stand <NUM> via a bearing not shown.

The basket trolley <NUM> includes a brake device <NUM> of the rotatable caster 4a set therein. As shown in <FIG>, the brake device <NUM> includes a brake part <NUM> set at the rotatable caster 4a, an operation part <NUM> set at a column 3b situated diagonally with respect to the fence <NUM> in the embodiment shown, and a power transfer means <NUM> for coupling the brake part <NUM> and the operation part <NUM>.

The brake part <NUM> includes a frame <NUM>. The frame <NUM> includes a tubular coupling tube <NUM>, and levers <NUM> projecting in a direction at right angles from the opposite ends thereof in the embodiment illustrated in <FIG>. Each lever <NUM> includes a claw 16a at the tip thereof. Then, the frame <NUM> is rotatably held by fitting the tubular coupling tube <NUM> to a shaft 5c set across the side-panels 5b, 5b of the fork <NUM>. Then, the frame <NUM> is arranged so that the levers <NUM> sandwich the roller <NUM> as shown in <FIG>. Further, a rod <NUM> for hanging a spring (or a direct cable) described later thereon is set across both the levers <NUM>.

Whereas, at the brake part <NUM>, a plurality of projecting parts <NUM> are formed at disks (the opposite side panels of the wheel) <NUM> on the opposite side-surfaces of the roller <NUM>. The projecting parts <NUM> are arranged at regular intervals in the circumferential direction concentrically with the disk <NUM>. Then, an inclined surface 19a making an acute angle with the outer circumferential surface is formed at the end of each projecting part <NUM>.

At the operation part <NUM>, a bracket <NUM> is set at the column 3b of the fence <NUM> as shown in <FIG>. An operation lever <NUM> is rotatably set at the bracket <NUM>. A tongue piece 21a for holding a cable described later is protrusively provided at the base of the operation lever <NUM>.

The power transfer means <NUM> includes a cable coupling unit <NUM> set at the side surface of the fence <NUM>. The cable coupling unit <NUM> includes a slide body <NUM> in a case <NUM> in the embodiment shown in <FIG>. The slide body <NUM> is for coupling an operation part side cable <NUM> and a brake part side cable <NUM>. With the cable coupling unit <NUM>, an outer tube 25a of the cable <NUM> is engaged with one end of the case <NUM>, and an outer tube 26a of the cable <NUM> is engaged with the other end of the case <NUM>. Then, an inner cable 25b of the cable <NUM> is engaged with one end of the slide body <NUM> by a screw <NUM>, and an inner cable 26b of the cable <NUM> is engaged with the other end of the slide body <NUM> via a spring <NUM>.

Further, with the cable coupling unit <NUM>, the slide body <NUM> is urged to the brake part side (downward of <FIG>) by a spring <NUM> fitted loosely to the inner cable 25b of the cable <NUM>. Incidentally, as shown in <FIG>, the cable <NUM> is guided upward from the operation part <NUM> along the column 3b, and crawls on the upper end and the side surface of the fence <NUM> to be guided to the cable coupling unit <NUM>. Whereas, the cable <NUM> crawls on the side surface of the fence <NUM> to be guided to the caster 4a, and is guided to the fork <NUM> through the rotation axis of the mount stand <NUM> as shown in <FIG>. The outer tube 26a of the cable <NUM> is engaged with the top panel 5a, and the inner cable 26b is rotatably coupled to the end of a spring <NUM> using a swivel mechanism. Then, the other end of the spring <NUM> is engaged with the rod <NUM> of the lever <NUM>.

Incidentally, when the spring <NUM> is provided at the cable coupling unit <NUM>, the spring <NUM> provided at the brake part <NUM> is not necessarily required. It may be configured such that the inner cable 26b of the cable <NUM> is directly coupled to the rod <NUM> of the lever <NUM>. Conversely, when the spring <NUM> is provided at the brake part <NUM>, for the cable coupling unit <NUM>, it may be configured such that the inner cable 26b of the cable <NUM> is directly engaged with the other end of the slide body <NUM> without the spring <NUM> interposed therebetween.

The opposite side end of the cable <NUM> is engaged with the tongue piece 21a of the operation lever <NUM> at the operation part <NUM> as shown in <FIG>.

With the brake device <NUM> of the rotatable caster 4a of the embodiment, in the normal state, namely, at the position at which the operation lever <NUM> is not operated as indicated with a solid line, the slide body <NUM> of the cable coupling unit <NUM> is moved toward the brake part (downward of <FIG>) by the urging force of the spring <NUM>. As a result, the inner cable 26b of the cable <NUM> is relaxed as shown in <FIG>, so that the lever <NUM> moves downward by its own weight, and further, the spring <NUM> or <NUM> presses thereagainst (in this case, the spring <NUM> or <NUM> performs an action of a press spring). Accordingly, the lever <NUM> is held downward, so that the claw 16a of the lever <NUM> is fitted into the concave part 19b between the projecting parts <NUM>. In this state, the roller <NUM> is locked against the rotation in the forward direction (also in the backward direction) of the trolley <NUM>. On the other hand, for the rotation in the counterclockwise direction of the roller <NUM>, the tip wall 16b of the lever <NUM> comes in touch with the end face 19c of the adjacent projecting part <NUM>, thereby hindering the rotation.

When the operation lever <NUM> is operated in the direction of the column 3b (the direction indicated with a two-dot chain line of <FIG>), the inner cable 25b of the cable <NUM> is lowered. As a result, the slide body <NUM> of the cable coupling unit <NUM> is pulled in the direction of the operation part (upward of <FIG>) against the urging force of the spring <NUM>. Then, the lever <NUM> is rotated upward in <FIG> via the inner cable 26b of the cable <NUM> connected to the slide body <NUM>. Accordingly, the claw 16a is separated from the projecting part <NUM> provided in addition on the roller <NUM>. Therefore, the rotation of the roller <NUM> becomes free, and the trolley <NUM> can be run in the desirable direction.

At this step, namely, in order to separate the claw 16a of the lever <NUM> from the projecting part <NUM>, it is necessary to rotate the roller <NUM> slightly anti-rotationally (in the counterclockwise direction in <FIG>). Meanwhile, the lifting force of the cable <NUM> acts on the lever <NUM>. The spring <NUM> interposed at an intermediate point of the cable, or the spring <NUM> interposed between the cable and the lever is stretched. As a result, the burden on the cable or the damage of the lever can be prevented. In addition, the stretched spring <NUM> or <NUM> also subsequently urges the lever <NUM> in the release direction (in this case, the spring <NUM> or <NUM> performs the action of a stretching spring), and performs the action of releasing the brake.

Incidentally, with the brake device for the embodiment, the inclined surface 19a is formed at the projecting part <NUM>, and the claw 16a of the lever <NUM> is caused to bite into the inclined surface 19a. Accordingly, the claw 16a is engaged with the projecting part <NUM> with reliability. When the angle of the inclined surface 19a, namely, the angle made between the line connecting the outer circumferential end of the projecting part <NUM> and the center of the roller <NUM> and the inclined surface is large, the engagement between the claw 16a of the lever <NUM> and the projecting part <NUM> becomes more firm. However, when the locking of the roller <NUM> is released, it becomes difficult to separate the claw 16a from the projecting part <NUM>. Therefore, in view of these, the angle is preferably about <NUM> to <NUM> degrees.

Further, in the embodiment, as shown in <FIG>, the end of the inner cable 26b and the lever <NUM> are coupled via the stretching spring <NUM>. However, the following is also acceptable. As shown in <FIG>, a T-shaped flat spring <NUM> is disposed by being laid across the levers <NUM>. A hole <NUM> is formed at the tip 31a, and one end of the inner cable 26b is rotatably coupled to the hole using a swivel mechanism or the like. The following is also acceptable. As shown in <FIG>, a torsion coil spring <NUM> is disposed by being laid across the levers <NUM>, and a hole 33a is formed at the center of the torsion coil spring <NUM>. One end of the inner cable 26b is rotatably coupled with the hole 33a using a swivel mechanism, or the like.

Further, in the embodiment, it is configured such that the lever <NUM> is engaged with the projecting part <NUM> projecting toward the side of the roller <NUM> from above as shown in <FIG>. However, the following configuration is also acceptable. As shown in <FIG>, the projecting part <NUM> is formed at the inner circumferential surface of the wheel <NUM> of the roller <NUM> in such a manner as to project in the direction of the shaft <NUM>, so that the lever <NUM> is engaged with the projecting part <NUM> from below. Incidentally, the members and the parts performing the same actions as those in the embodiment are given the same reference numerals and signs in <FIG>, and the description thereon is omitted.

Further, in the embodiment, as shown in <FIG>, the configuration of the cable coupling unit <NUM> is configured such that the inner cable 26b of the brake part side cable <NUM> is engaged with the other end of the slide body <NUM> via the spring <NUM>. However, when the spring <NUM> is provided at the brake part <NUM>, as shown in <FIG>, for the cable coupling unit <NUM>, it may be configured such that the inner cable 26b of the cable <NUM> is directly engaged, by a screw <NUM>, with the other end of the slide body <NUM> without the spring <NUM> interposed therebetween.

Up to this point, a description has been given to the embodiments of the brake device for the rotatable caster in accordance with the present invention. However, it is naturally understood that the present invention is not limited to the embodiments at all, and may be variously modified or changed within the scope of the appended claims.

Claim 1:
A brake device (<NUM>) for a caster (<NUM>, 4a) comprising: a plurality of projecting parts (<NUM>) formed concentrically on opposite side-surfaces of a roller (<NUM>), and levers (<NUM>) set across the roller (<NUM>) at opposite side-panels (5b) of a fork (<NUM>) so as to be opposed to the projecting parts (<NUM>), and a claw (16a) formed at a tip of each of the levers (<NUM>) so as to be opposed to each of the projecting parts (<NUM>), wherein the levers (<NUM>) are operated, so that the claw (16a) is engaged with a concave part (19b) formed between the projecting parts (<NUM>), to lock the rotation of the roller (<NUM>), characterized in that a cable coupling unit (<NUM>) having a slide body (<NUM>) is set at an intermediate point of a cable (<NUM>, <NUM>), and the cable (<NUM>) on an operation lever (<NUM>) side and the cable (<NUM>) on the lever (<NUM>) side are coupled via the slide body (<NUM>), wherein the cable coupling unit (<NUM>) comprises at least one compression spring (<NUM>), wherein at least one tension spring (<NUM>, <NUM>, <NUM>, <NUM>) is operatively interposed between the cable (<NUM>) and the slide body (<NUM>) and/or the cable (<NUM>) and the lever (<NUM>).