JP2002331803A - Caster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a lock mechanism for locking a wheel horizontally unturnably have a simple structure. SOLUTION: This caster is provided with a pair of left and right wheels 1, a supporting block 2 mounted with the wheels 1 by an axle 9 and a support shaft 3 fitted rotatably with the supporting block 2 therein, as a basic structure. The support shaft 3 is fixed non-rotatably to a leg 13 of furniture. In the axle 9, a ring-shaped movable lock body 5 is elevatably/lowerably fitted. The movable lock body 5 becomes non-rotatable at a lowering position and is rotatable when the lock body 5 finishes to rise. An engagement groove 22 formed in the movable lock body 5 is fitted into an engagement projection 7 of the supporting block 2 and thereby the wheels 1 are locked horizontally unturnably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caster used for furniture such as a table (desk), counter, bed or chair.

[0002]

2. Description of the Related Art Casters used for furniture are provided with wheels that roll on the floor. Generally, wheels are turned horizontally (swing).

[0003] The reason why the wheels are turned horizontally is to enable furniture to be moved in any direction. In some cases, furniture is moved only in a specific direction. You may want to do that.

For example, as shown in FIG. 15A, when it is desired to move an arc-shaped table D around a circumference having a radius of curvature in plan view, or as shown in FIG. In some cases, it is desired to move the rectangular table D only in the front-rear direction (reference numeral D1 is a leg, and casters are attached to both ends of the leg D1).

In hospital beds, there is a strong demand to suppress meandering and secure straight traveling when moving in a corridor or the like.

Therefore, a lock mechanism for switching the wheels of the caster from a free state in which the wheels can be turned horizontally to a locked state in which the wheels cannot be turned horizontally has been provided.

For example, Japanese Patent Application Laid-Open No. 60-135303 and US Pat. No. 4,205,413 disclose that one wheel is mounted on a downwardly open U-shaped sheet metal bracket, and the bracket is eccentric from the rotation axis of the wheel in plan view. The part
In a one-wheel type caster which is attached to a fixed member fixed to furniture so as to be horizontally rotatable, the fixed member is provided with a movable lock member of an elevating type or a rotating type, and the movable lock member is fitted to a bracket. It is described that a stopper is provided for detachment, and the movable lock member is operated to switch between a free state and a locked state.

Further, Japanese Utility Model Application Laid-Open No. 58-179203 and US Pat.
P38812116 and U.S. Pat. No. 2,709,828 disclose a one-wheel type caster having a basic structure similar to that of each of the above publications, in which a stopper having an uneven engaging portion formed on an outer peripheral surface is provided on a fixing member such as a support shaft. On the other hand, it is described that the bracket is provided with a slide-type or rotary-type movable lock body that fits into and disengages from the stopper.

[0009]

By the way, in the case of a swing type caster, if the center of rotation of the wheel is too far from the center of rotation of the wheel, the wheel will not be able to move horizontally when turning horizontally. There is a problem that a collision may occur, or an excessive bending moment acts on a mounting portion between the caster and the furniture.

For this reason, the horizontal turning center of the wheel is located closer to the rotation center than the outer periphery of the wheel. In other words,
The eccentric distance from the rotation axis of the wheel to the horizontal turning center is smaller than the radius of the wheel. In addition, in the one-wheel type caster as in each of the above-described prior arts, the upper surface plate of the bracket inevitably overlaps the wheel in plan view.

Therefore, in a one-wheel type caster, in order to prevent a fixed member such as a spindle from interfering with the wheel, the fixed member such as a spindle must be rotatably mounted on the upper plate of the bracket by a thrust bearing. Therefore, the mechanism for horizontally turning the wheels tends to be complicated.

The mechanism for horizontally turning the wheels has a complicated structure originally in a narrow space, and further includes a lock mechanism such as a movable lock body and a stopper. The structure tends to be extremely complicated.

An object of the present invention is to improve such a situation.

[0014]

According to a first aspect of the present invention, a caster includes a support block, and a pair of wheels symmetrically disposed on both left and right sides of the support block. The pair of wheels are attached to a support block so as to rotate around a common horizontal axis.
The support block is horizontally rotatably attached to a vertical support shaft at a portion eccentric from the rotation axis of the wheel in a plan view, and the upper portion of the support shaft is fixed to the furniture body so as not to rotate. Further, there is provided a lock mechanism for switching the support block between a free state in which the support block can be turned horizontally and a locked state in which the support block cannot be turned horizontally.

According to a second aspect of the present invention, in the caster according to the first aspect, a ring-shaped movable lock body is fitted on the support shaft so as to be vertically movable. Locking means for holding the lowered movable lock body unrotatably and free locking means for holding the raised movable lock body unrotatably are formed.

Further, the movable lock body and the support block are provided with stoppers which are fitted to each other in a state where the movable lock body is lowered and hold the support block so as not to be able to turn horizontally. The lock mechanism is constituted by the body, the locking means, and the stopper means.

According to a third aspect of the present invention, in the second aspect,
The stopper means of the movable lock body is an engagement groove having a downward opening, while the stopper means of the support block is an upward engagement protrusion, and the lower surface of the movable lock body has an arbitrary rotation posture excluding the engagement groove. Has a flat surface that can abut the engagement protrusion, and further urges the movable lock body downward with a spring.

[0018]

According to the present invention, since the support block is located between the left and right wheels, the shape of the support block and the height position from the floor are not restricted by the wheels.

Therefore, even with a simple structure in which the support shaft is inserted into the vertically long holes formed in the support block, the support block can be mounted on the support shaft in a stable state. That is, the mounting structure of the support block to the support shaft can be simplified. Since there is little space restriction in providing the lock mechanism, the above-mentioned Japanese Patent Application Laid-Open No. 60-135 is disclosed.
The lock mechanism can also adopt a simple structure as compared with the structure in which the operation shaft is built in the support shaft as disclosed in JP-A-303.

According to the second aspect of the present invention, the movable state can be switched between the free state and the locked state only by changing the height of the movable lock body fitted to the support shaft from the outside, so that the structure is further simplified.

By the way, when locking the attitude of the wheels,
There are a case where the furniture is locked in an arbitrary horizontal posture and a case where the furniture is locked in a specific posture. When the furniture is to be moved only in a specific direction, the wheels are locked in a specific plane posture.

In the case of each of the above-mentioned prior arts of the latter type, the wheel is horizontally turned to a predetermined posture, and then the lever or the like is operated to fit the movable lock body and the stopper, so that the operation is not performed. It is troublesome.

On the other hand, according to the third aspect of the present invention, since the movable lock body is urged downward by the spring, when the movable lock body can be lowered and the wheel is turned horizontally, the wheel is rotated. At the time when the posture becomes a predetermined posture, the movable lock body and the engagement protrusion are automatically fitted to each other to be in a locked state. Therefore, the operation of locking the wheel in a specific posture is simple, and the free state and the locked state can be reliably held by the presence of the spring.

[0024]

Next, embodiments of the present invention will be described with reference to the drawings.

(1) First Embodiment (FIGS. 1 to 8) FIGS. 1 to 7 show a first embodiment. FIG. 1 is an exploded perspective view, FIG. 2 is an exploded front view, and FIG. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3, FIG. 5 is a vertical cross-sectional view taken along line IV-IV of FIG. 3, FIG. 6 is a cross-sectional view taken along line VI-VI of FIG.
FIG. 7 is a sectional view taken along line VII-VII of FIG.

For example, as can be understood from FIGS. 1 and 2, the caster includes a pair of left and right wheels (rollers) 1, a support block 2 disposed between the left and right wheels 1, and a support having a male screw 4 formed on an upper portion. The shaft 3 includes a movable lock body 5 fitted on the support shaft 3, an engagement protrusion 7 fixed to the upper surface of the support block 2 with screws 6, and a spring 8. The left and right wheels 1 are rotatably mounted on the support block 2 on a common axle 9.

The support block 2 is made of a synthetic resin (or may be made of metal such as a sheet metal), and a bearing 10 is formed at a rear portion thereof so as to protrude slightly upward. The support block 2 is fitted from above. The support shaft 3 is fixed to the support block 2 by a snap ring 11. In addition, since the support block 2 is made of a synthetic resin, the support block 2 smoothly turns horizontally without a bearing.

The engagement protrusion 7 is fixed to the support block 2 with a screw 6 at a position on the near side of the bearing 10.
In this case, the engaging projections 7 are provided so that the heads of the screws 6 are not exposed.
Has a counterbore.

A lock nut 12 is screwed into the male screw 4 of the support shaft 3.
3, the support shaft 3 is non-rotatably fixed to the furniture leg 13 by tightening the lock nut 12.

The support shaft 3 has a lower flange 16 for receiving a load on the support block 2, an upper flange 17 located at the base of the male screw 4, and a step 18 integrally formed on the lower surface of the upper flange 17. Are formed, and the step portion 1 is formed.
A guide 19 for the movable lock body 5 is provided between the lower flange 8 and the lower flange 16.

As clearly shown in FIG. 3 and FIG.
Is located slightly below the upper surface of the lower flange 16 of the support shaft 3. As shown in FIG. 1, for example, a flat surface 20 extending in parallel in a plan view is formed on the outer peripheral surface of the lower flange 16 of the support shaft 3,
The outer diameter of the guide portion 19 is inscribed in the flat surface 20.

The movable lock body 5 has a pair of inward projections 21 corresponding to the flat surface of the lower flange 16 on its inner peripheral surface so as to fit into the lower flange 16 of the support shaft 3 so as to be non-rotatably movable up and down. Are formed.

In this case, by forming only the upper part of the inner peripheral surface of the movable lock body 5 into a perfect circle without forming the inward projection 21 at the upper end of the movable lock body 5,
Is raised, the upper part is fitted to the step 18 of the support shaft 3 without play. When the movable lock body 5 is raised to a state in which it is fitted to the step 18 of the support shaft 3, the movable lock body 5 is set so as to be detachable from the lower flange 16 and to be rotatable.

One end of the movable lock body 5 along a center line extending in parallel with the inward projection 21 in plan view,
As an example of the stopper means according to the second aspect, an engaging groove 22 that fits into the engaging protrusion 7 from above in a lowered state is formed. The upper corner of the engagement protrusion 7 is
The engaging groove 22 is chamfered so as to be easily fitted (the lower end of the engaging groove 22 may be formed in a tapered shape).

The spring 8 described above is interposed between the movable lock 5 and the furniture leg 13, and the movable lock 5 is urged downward by the spring 8.

The flat surface 20 of the lower flange 16 of the support shaft 3 and the inward projection 21 of the movable lock body 5 are defined in claim 2.
2 is an example of the locking means described in (1). Also, the lower flange 16 of the support shaft 3 and the inward projection 2 of the movable lock body 5
1 is an example of the locking means for free as described in claim 2.

In the above configuration, when the movable lock body 5 is lowered, the engagement groove 22 of the movable lock body 5 fits into the engagement protrusion 7 of the support block 2 as shown in FIGS. By doing so, the support block 2 and the wheels 1 are held so that they cannot turn horizontally. Therefore, the furniture can be moved only in a specific direction.

In this locked state, the movable lock body 5 is pushed downward by the spring 8, so that when the furniture is moved, the phenomenon that the movable lock body 5 jumps up due to vibration does not occur, and the locked state is securely held. Is done.

As shown by a dashed line in FIG. 3, when the movable lock body 5 is picked up by a person and raised to the upper limit, the movable lock body 5 separates from the engagement protrusion 7 of the support block 2 and becomes free. Become.

Next, when the movable lock body 5 is rotated to some extent (for example, about 90 degrees) in any direction, the inward projection 21 of the movable lock body 5 is moved downwardly of the support shaft 3 as shown in FIGS. It rests on the flange 16. Thereby, the movable lock body 5 is held in a state of being separated from the engagement protrusion 7. Therefore, the support block 2 and the wheel 1 are held in a free state (unlocked state) in which the support block 2 and the wheel 1 can be turned horizontally.

In this free state, the movable lock 5
Is pressed downward by the spring 8, the movable lock body 5 does not easily rotate even if vibration is applied by the movement of the furniture, and the free state is reliably maintained.

When the movable lock body 5 in the free state is rotated to a position in which the movable lock body 5 is fitted to the lower flange 16 of the support shaft 3 and then released, the upper surface of the engagement protrusion 7 becomes larger than the upper surface of the lower flange 16. Due to the high height, the movable lock body 5 is pushed from above by the engagement projections 7 in a non-rotatable state when the wheel 1 is not in the locked position.

When a person turns the wheel 1 or the support block 2 horizontally in either direction by hand, the movable lock 5 is moved downward by the pressing force of the spring 8 at the same time that the wheel 1 is in the locked position. Then, the movable lock body 5 and the engagement protrusion 7 are automatically fitted to each other to be in a locked state.

The movable lock body 5 can be automatically locked only by its own weight. However, when the spring 8 is provided as in claim 3, it is possible to reliably shift to the locked state and to ensure the free state. Therefore, it is suitable.

(2) Second Embodiment (FIG. 8) FIG. 8 shows a second embodiment which is a modification of the first embodiment. That is, in this embodiment, the engagement protrusion 7 is formed integrally with the support block 2, and the up-and-down telescopic cover 23 that covers the spring 8 is provided. Movable lock body 5
Is provided with an enclosing wall 5a for preventing the cover 23 from shifting laterally. The cover 23 may have a bellows shape or a simple rubber cylinder.

(3) Third Embodiment (FIG. 9) FIG. 9 shows a third embodiment, in which (A) is a longitudinal side view, and (B) is a partial BB view of (A). It is a front view.
In the third embodiment, an engagement groove 22 having an upward opening is formed in the support block 2, and a downward engagement protrusion 24 is formed in the movable lock body 5. Other structures are the same as those of the first embodiment.

As can be easily understood from this example, the engaging groove 22 and the engaging projection 24 as the stopper means may be formed on either the movable lock body 5 or the support block 2. In the third embodiment, when switching from the free state to the locked state, the movable lock body 5 is lowered after turning the wheels 1 and the support block 2 to a predetermined locked posture.

(4) Fourth Embodiment (FIG. 10) FIG. 10 shows a fourth embodiment. (A) is a longitudinal sectional side view, (B) is a partial BB front view of (A). In this embodiment, an engaging groove 22 having an upward opening is formed in the support block 2 as an example of a stopper means, while a pivotable movable lock that fits into and disengages from the engaging groove 22 is formed in the support shaft 3. The body 5 is attached by a horizontally extending pin 25.

Although not shown, the movable lock 5 and the support shaft 3 are provided with locking means for selectively holding the movable lock 5 in a locked state and a free state. The movable lock body 5 is made of sheet metal, but may be made of synthetic resin. In this embodiment, since the movable lock body 5 is only rotated, the vertical height of the caster can be reduced.

(5) Fifth Embodiment (FIG. 11) FIG. 11 shows a fifth embodiment. (A) is a longitudinal sectional side view, (B) is a partial BB front view of (A). In this embodiment, a stopper 26 made of a synthetic resin also serving as a washer is non-rotatably fitted to the support shaft 3, and the engagement groove 22 opened forward and downward is formed in the stopper 26, while the support block 2 is , The support block 2
Is mounted on the movable lock body 5 sandwiching.

The movable lock 5 rotates vertically about the axle 9. In addition, on the left and right sides of the support block 2, a fan-shaped groove 27 for restricting the rotation range of the movable lock body 5 is provided.
Is formed. Although not shown, the support block 2 and the movable lock body 5 are provided with locking means for selectively switching the movable lock body 5 between a locked state and a free state.

(6) Sixth Embodiment (FIG. 12) FIG. 11 shows a fifth embodiment. (A) is a longitudinal side view, and (B) is a plan sectional view taken along the line BB of (A). In this embodiment, a boss portion 28 of the support shaft 3 which is placed on the bearing portion 10 of the support block 2 is formed in a quadrangular cross section, and the movable lock body 5 is non-rotatably fitted into the square boss portion 28 in a vertically movable manner. In.

The bearing 1 of the support block 2
0, the portion projecting upward is attached to the boss 28 of the support shaft 3.
The stopper portion 10a has the same planar shape as that of the stopper portion 10a. In this embodiment, it is possible to switch between the free state and the locked state by moving the movable lock body 5 up and down.

Also in this example, although not shown, the movable lock body 5 and the support shaft 3 are provided with locking means for holding the movable lock body 5 at least in the raised position.

As the locking means, for example, a ball pushed by a spring is incorporated in the upper part of the movable lock body 5, and the movable lock body 5 is raised and lowered in the boss portion of the support shaft 3. Various methods such as a so-called ball catching method in which two upper and lower semicircular holes into which the balls fit are formed can be adopted. The posture may be held by interposing a friction member.

(7) Other applicable casters FIG. 13 shows a caster in which the support block 2 is integrally provided with a cover 2a for covering the wheel 1 from above.
Although a specific configuration is not shown, the present invention can be applied to such a type of caster.

(8). Related Invention (FIG. 14) FIG. 14 shows a one-wheel type caster related to the present invention. That is, in the example of FIG. 14, a bearing 31 is provided at the rear of the support 30 to which one wheel 1 is attached.
Is projected upward, and the adjustment nut 3
2, the support shaft 3 is inserted. At the upper end of the spindle 3,
A mounting plate 33 screwed to the furniture is fixed.

Then, the square portion 34 provided above the support shaft 3
The movable lock body 5 of the up-and-down type is rotatably fitted in a non-rotatable manner to form an engaging groove 22 on a flange 5 b provided at a lower end of the movable lock body 5. An engagement projection 7 to be fitted and removed is formed. The movable lock body 5 is urged downward by a spring 8.

Although not shown in detail, the support shaft 3 and the movable lock body 5 are provided with locking means for selectively holding the movable lock body 5 at the raised position and the lowered position. I have.

When this example is compared with the present invention, the movable lock body 5 is provided on the support shaft 3 so as to be able to move up and down, and the movable lock body 5 is fitted into and disengaged from the engagement projection 7 or the engagement groove 22 so as to lock. They are common in that they switch between a state and a free state.

Accordingly, when viewed as a mounting structure for the movable lock body 5, the invention in which the movable lock body 5 is fitted into the support shaft from the outside and the movable lock body is raised and lowered to switch between the locked state and the free state is as follows. The present invention can be applied regardless of whether it is a one-wheel type or a two-wheel type.

In any case, the movable lock 5
Since the is fitted to the support shaft from the outside, the mounting structure is simple and the effect that the person can easily operate by hand is provided.

(9). Others The present invention can be variously embodied in addition to the above embodiments. For example, the shape of the support block and the shape of the support shaft can be variously embodied as needed. As a means for fixing the support shaft 3 to the furniture main body, a mounting plate may be fixed to the upper end of the support shaft, as in FIG.

Further, a plurality of casters are attached to the furniture. However, it is also possible to simultaneously operate the movable locks of the casters by the interlocking means.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a first embodiment.

FIG. 2 is a separate front view.

FIG. 3 is a longitudinal sectional side view in a locked state.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a vertical side view in a free state.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a diagram showing a second embodiment.

FIG. 9 is a diagram showing a third embodiment.

FIG. 10 is a diagram illustrating a fourth embodiment.

FIG. 11 is a diagram showing a fifth embodiment.

FIG. 12 is a diagram illustrating a sixth embodiment;

FIG. 13 is a diagram illustrating a seventh embodiment;

FIG. 14 is a view showing a caster related to the present invention.

FIG. 15 is a diagram showing a conventional technique.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Wheel 2 Support block 3 Support shaft 4 Male screw 5 Movable lock body 7 Engagement projection which constitutes stopper means 8 Spring 16 Lower flange which constitutes free lock means 21 Inward projection which constitutes lock engagement means 22 Stopper Engagement groove constituting the means

Claims (3)

[Claims] 1. A vehicle comprising: a support block; and a pair of wheels symmetrically disposed on both left and right sides of the support block, wherein the pair of wheels are supported so as to rotate about a common horizontal axis. On the other hand, the support block is attached to a vertical support shaft so as to be horizontally eccentric at a position eccentric from the rotation axis of the wheel in plan view, and the upper portion of the support shaft is attached to the furniture body. A caster which is adapted to be fixed so as not to rotate, and further provided with a lock mechanism for switching the support block between a free state in which the support block can be turned horizontally and a locked state in which the support block cannot be turned horizontally. 2. A ring-shaped movable lock body is fitted on the support shaft so as to be movable up and down, and a lock for holding the lowered movable lock body in a non-rotatable manner between the movable lock body and the support shaft. Locking means, and a free locking means for holding the raised movable lock body so as to be unable to descend. Further, the movable lock body and the support block have the movable lock body lowered. 2. A stopper means which is fitted to each other in a state and holds the support block so that the support block cannot be turned horizontally, wherein the movable lock body, the locking means and the stopper means constitute the lock mechanism. Casters described in. 3. The stopper means of the movable lock body is an engagement groove having a downward opening, while the stopper means of the support block is an upward engagement protrusion. The caster according to claim 2, wherein the caster has a flat surface capable of contacting the engaging projection in an arbitrary rotation posture, and further urges the movable lock body downward with a spring.