U.S. patent application number 16/799323 was filed with the patent office on 2021-08-26 for fixing structure for a foot ring of a chair.
This patent application is currently assigned to Fusco Industrial Corporation. The applicant listed for this patent is Fusco Industrial Corporation. Invention is credited to Chen-Yu Tsai.
Application Number | 20210259424 16/799323 |
Document ID | / |
Family ID | 1000005764817 |
Filed Date | 2021-08-26 |
United States Patent
Application |
20210259424 |
Kind Code |
A1 |
Tsai; Chen-Yu |
August 26, 2021 |
Fixing Structure for a Foot Ring of a Chair
Abstract
A fixing structure for a foot ring of a chair includes the foot
ring having a hub with a central hole formed with internal threads
on an inner surface thereof; and a bush being a cylindrical body
having a tapered outer surface with external threads formed
thereon. The bush has a shaft hole penetrating along a longitudinal
axis of the bush, a groove penetrating through a wall of the bush,
and at least one pad provided on an inner surface of the shaft hole
of the bush. The bush is assembled with the hub by screwing the
external threads of the bush with the internal threads of the hub.
A supporting post penetrates through the shaft hole of the bush.
When the bush rotates toward a first direction, the shaft hole is
reduced to clamp and fix the supporting post, and when the bush
rotates toward a second direction, the shaft hole is enlarged to
release the clamping and fixing of the supporting post.
Inventors: |
Tsai; Chen-Yu; (Taipei City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fusco Industrial Corporation |
Taipei City |
|
TW |
|
|
Assignee: |
Fusco Industrial
Corporation
|
Family ID: |
1000005764817 |
Appl. No.: |
16/799323 |
Filed: |
February 24, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A47C 7/5064 20180801;
A47C 7/02 20130101; A47C 7/004 20130101 |
International
Class: |
A47C 7/02 20060101
A47C007/02; A47C 7/50 20060101 A47C007/50; A47C 7/00 20060101
A47C007/00 |
Claims
1. A structure for fixing a foot ring to a chair, comprising: a
ring body, a hub arranged concentrically with the ring body, and a
plurality of spokes radially arranged between an inner periphery of
the ring body and an outer periphery of the hub, wherein the hub
has a central hole formed with internal threads on an inner surface
thereof; and a bush being a cylindrical body having a tapered outer
surface with external threads formed thereon, wherein the bush has
a shaft hole penetrating along a longitudinal axis of the bush,
wherein two recesses are formed on the opposite sides of the inner
surface of the shaft hole, the two recesses are respectively
extending through the inner surface along the axial of the shaft
hole, and two pads are respectively disposed on and protrude from
the recesses, the two pads are softer and having a higher
coefficient of friction compared to a coefficient of friction of
the inner surface of the shaft hole, and a groove penetrating
through a wall of the bush, wherein two opposite sidewalls of the
groove have a width spaced apart from each other, and form an angle
in a widthwise direction thereof, wherein the range of the angle is
5.degree. to 8.degree., wherein the range of the width is 5 to 10
mm, and wherein the bush is assembled with the hub by screwing the
external threads of the bush with the internal threads of the hub,
a supporting post penetrates through the shaft hole of the bush,
and when the bush rotates toward a first direction, the wall of the
bush is restricted by the central hole and the inner diameter of
the shaft hole is reduced to clamp and fix the supporting post,
when the bush rotates toward a second direction, the wall of the
bush restricted by the central hole is released to make the shaft
hole enlarge to release the clamping and fixing of the supporting
post, wherein the first direction and the second direction are
opposite to each other.
2. The fixing structure of claim 1, wherein an outer edge of a
large diameter end of the tapered bush is formed with a flange
protruding radially outward.
3-7. (canceled)
8. The fixing structure of claim 1, wherein the pads are adhesively
fixed on a bottom surface of the recesses.
9. The fixing structure of claim 1, wherein the two pads are made
of silicone or rubber material.
10. The fixing structure of claim 1, wherein the supporting post is
a pneumatic cylinder for providing a seat of the chair to be raised
or lowered.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a chair with a foot ring in
the field of furniture, more particular to a fixing structure for
fixing the foot ring to a supporting post or a pneumatic cylinder
for controlling the lifting of a seat of the chair.
2. The Prior Arts
[0002] Some chairs are provided with a foot ring at an appropriate
height position of a supporting post used to support a seat, so
that people's feet can be placed on the foot ring while sifting on
the seat and feel comfortable.
[0003] A conventional foot ring of a chair includes a ring body and
a hub arranged concentrically, and a plurality of spokes radially
arranged between an inner periphery of the ring body and an outer
periphery of the hub. The hub has a central hole for a supporting
post or a pneumatic cylinder, which is used to support the seat of
the chair, to penetrate through.
[0004] Some early foot rings for a chair were made by a fixed
manner (that is, the height position of the foot rings cannot be
adjusted), so those with a larger size may feel uncomfortable due
to their knees bending too much when sifting, and those with a
smaller size may also feel uncomfortable due to their knees
stretching too much.
[0005] Taiwanese Utility Patent No. 298787 provides a fixing device
for ascending/descending a foot ring of a chair, which includes a
clamping ring with a slot provided in a central hole of a hub of
the foot ring. A sliding groove is provided axially on an inner
wall of the hub, and a pressing sheet is arranged therein. The hub
is provided with a screw hole radially extending through the inner
wall of the hub and corresponding to the sliding groove for being
fitted with a screw coupled to a knob. After a supporting post is
inserted into the clamping ring, the screw coupled to the knob can
be used to press against the pressing sheet for controlling whether
the clamping ring is fixed to the supporting post or not. That is,
when the clamping ring is not clamped and fixed, the height
position of the foot ring on the supporting post can be adjusted up
and down; and when a desired height position of the foot ring is
reached, the clamping ring is clamped and fixed.
[0006] However, since the pressing sheet is straight shape, when
the screw coupled to the knob acts on the pressing sheet, the
straight-shape pressing sheet only acts on a point of an outer
surface of the clamping ring, so that the wall of the clamping ring
on one side of the groove has a larger deformation, while the wall
of the clamping ring on the other side of the groove is almost not
deformed, which causes the clamping ring to receive an uneven force
and thus reduces a clamping force of the clamping ring on the
supporting post.
[0007] Taiwanese Utility Patent No. 516411 provides an improved
foot ring for a chair, which has a hub with a sliding groove on an
inner wall and in parallel to a central axis thereof, and an
arc-shape pressing sheet arranged in the sliding groove. A clamping
ring with a slot is disposed in a central hole of the hub, so as to
provide two ends of the arc-shape pressing sheet against two sides
of the slot of the clamping ring. A screw coupled to a knob is
screwed into a screw hole on the wall of the hub. A user can
control whether the clamping ring is fixed to a supporting post
penetrated through the clamping ring or not by tightening or
loosening the knob.
SUMMARY OF THE INVENTION
[0008] The objective of the present invention is to provide a
fixing structure for a foot ring of a chair with a more simplified
structure and an easier operation.
[0009] The technical means of the present invention is to provide a
fixing structure for a foot ring of a chair, comprising: the foot
ring having a ring body, a hub arranged concentrically with the
ring body, and a plurality of spokes radially arranged between an
inner periphery of the ring body and an outer periphery of the hub,
wherein the hub has a central hole formed with internal threads on
an inner surface thereof; and a bush being a cylindrical body
having a tapered outer surface with external threads formed
thereon, wherein the bush has a shaft hole penetrating along a
longitudinal axis of the bush, a groove penetrating through a wall
of the bush, and at least one pad provided on an inner surface of
the shaft hole, which is softer relative to the inner surface of
the shaft hole and has a relatively high coefficient of friction,
wherein the bush is assembled with the hub by screwing the external
threads of the bush with the internal threads of the hub, a
supporting post penetrates the shaft hole of the bush, and when the
bush rotates toward a first direction, the wall of the bush is
restricted by the central hole and the inner diameter of the shaft
hole is reduced to clamp and fix the supporting post, when the bush
rotates toward a second direction, the wall of the bush restricted
by the central hole is released to make the shaft hole enlarge to
release the clamping and fixing of the supporting post, wherein the
first direction and the second direction are opposite to each
other.
[0010] Preferably, an outer edge of a large diameter end of the
tapered bush is formed with a flange protruding radially outward,
so that the bush can rotate into the central hole of the hub until
the flange is obstructed by an edge of the hub.
[0011] Preferably, opposite sidewalls of the groove have a width
spaced apart from each other, and form an angle in a widthwise
direction thereof, so that when the bush rotates into the central
hole of the hub to reduce the inner diameter of the shaft hole, the
two sidewalls of the groove gradually close to each other, and
finally may contact with each other.
[0012] In a suitable embodiment, the angle between the two
sidewalls of the groove may be 5.degree..about.8.degree..
[0013] In a suitable embodiment, the width between the two
sidewalls of the groove may be 5.about.10 mm.
[0014] Preferably, two pads may be disposed on and protrude from
opposite sides of the inner surface of the shaft hole.
[0015] Preferably, two recesses may be formed on opposite sides of
the inner surface of the shaft hole, and the pads are respectively
fixed in the recesses.
[0016] In a suitable embodiment, the pads may be adhesively fixed
on a bottom surface of the recess.
[0017] In a suitable embodiment, the pads may be made of silicone
or rubber material.
[0018] In a suitable embodiment, the supporting post may be a
pneumatic cylinder for providing a seat of the chair to be raised
or lowered.
[0019] Compared with the conventional fixing structure of a foot
ring for a chair, the fixing structure of the present invention
used to fix the foot ring to a supporting post or a pneumatic
cylinder is simple, easy to be assembled, and easy to adjust the
height position of the foot ring on the supporting post.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 illustrates a schematic perspective view of a foot
ring according to an embodiment of the present invention, which is
assembled on a supporting post of a chair;
[0021] FIG. 2 illustrates an exploded perspective view of an
assembled relationship of the foot ring, the bush and the
supporting post;
[0022] FIG. 3 illustrates an exploded perspective view of an
assembled structure of the bush and the pads;
[0023] FIG. 4 illustrates a front view of the bush;
[0024] FIG. 5 illustrates a top view of the bush;
[0025] FIG. 6 illustrates a front sectional view showing the foot
ring and the bush fixedly assembled with the supporting post;
[0026] FIG. 7 illustrates a top plan sectional view showing the
foot ring and the bush fixedly assembled with the supporting post;
and
[0027] FIG. 8 illustrates a top plan sectional view showing a state
in which the foot ring and the bush are released from the
supporting post.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] The following describes the implementation of the present
invention in more detail with drawings and numerals, so that those
skilled in the art can implement it after studying the present
specification.
[0029] As shown in FIG. 1, the foot ring 1 of the present invention
is assembled at an appropriate height position of a supporting post
3 of a chair, so that the feet of a user sitting on the chair can
step thereon and feel comfortable. The fixing structure is to allow
the foot ring 1 to be quickly, stably and firmly mounted on the
supporting post 3. The chair is suitable for a chair having a
single supporting post, such as an office chair and a high
chair.
[0030] The supporting post 3 may be a rod generally used to support
a chair, or may be a pneumatic cylinder used to support a seat of a
chair and capable of controlling the seat to be raised or lowered
in a vertical direction.
[0031] As shown in FIG. 2, the fixing structure of the foot ring
for a chair provided in the present invention preferably comprises
a foot ring 1 and a bush 2. The foot ring 1 can be made of any
suitable material, for example, which is made of aluminum alloy
material by casting. The foot ring 1 has a ring body 11 and a hub
12 arranged concentrically each other, and a plurality of spokes 13
are radially arranged between an inner periphery of the ring body
11 and an outer periphery of the hub 12. The spokes 13 connect the
ring body 11 and the hub 12 together and maintain both at a
concentric position. The hub 12 has a central hole 121, which is
formed with internal threads 122 on an inner surface thereof by
turning.
[0032] As shown in FIGS. 3 to 5, the bush 2 can be integrally
formed by a plastic material, a composite material or any suitable
material to be a cylindrical body having a tapered outer surface
with external threads 21 formed thereon, so as to form the bush 2
with a shaft hole 20 penetrating along a longitudinal axis of the
bush. An outer edge of the large diameter end of the tapered-shape
bush 2 is formed with a flange 24 protruding radially outward. A
groove 22 is formed to penetrate through a wall of the bush 2. Two
opposite sidewalls of the groove have a width W spaced apart from
each other, and form an angle .theta. in a widthwise direction
thereof. The angle .theta. is preferably 5.degree. to 8.degree.,
and the width W is preferably 5 mm to 10 mm. The groove 22 may
provide the wall of the bush 2 to be elastically deformed in a
radial direction, so as to elastically reduce or enlarge an inner
diameter of the shaft hole 20. The angle .theta. may provide the
opposite sidewalls of the groove 22 to be close to each other when
the shaft hole 20 is reduced to a certain degree.
[0033] The width W of the groove 22 should be suitably set, so as
to provide a sufficient contact area for obtaining an enough
clamping force between an outer surface of the supporting post 3
and the inner surface of the shaft hole 20 when the supporting post
3 penetrates through the shaft hole 20. In other words, if the
width W is too large, the inner surface area of the shaft hole 20
will decrease, and thus the contact area between the outer surface
of the supporting post 3 and the inner surface of the shaft hole 20
will decrease, thereby reducing the frictional force of the contact
surface of the inner surface of the shaft hole 20 with the outer
surface of the supporting post 3. In contrast, if the width W is
too small, although the inner surface area of the shaft hole 20 is
relatively increased, an deformation amount of the bush 2 in the
radial direction will be decreased due to the contact of the
opposite sidewalls of the groove 22 with each other, and thereby
decreasing the clamping force of the bush 2 on the supporting post
3. Therefore, the optimal width W of the groove 22 at an outer edge
of the bush 2 is 5 mm to 10 mm.
[0034] In the preferred embodiment of the present invention, at
least one pad 23 may be further provided on the inner surface of
the shaft hole 20, and the at least one pad 23 may protrude from
the inner surface of the shaft hole 20. The pad 23 is softer
relative to the inner surface of the shaft hole 20 and has a high
coefficient of friction. For example, the pad 23 may be made of
silicone or rubber material. Preferably, recesses 201 may be formed
on opposite sides of the inner surface of the shaft hole 20, and
two pads 23 are respectively disposed in the recesses 201. For
example, the pad 23 may be fixed on a bottom surface of the recess
201 with an adhesive; or the pad 23 may be pressed into the recess
201 in a tight fit manner.
[0035] The operation method of fixing the foot ring 1 to the
supporting post 3 using the fixing structure is described below:
The bush 2 is assembled with the hub 12 by spirally fitting the
internal thread 122 with the external thread 21, so as to make the
bush 2 penetrate into the central hole 121 along the longitudinal
axis thereof. Since the bush 2 having a tapered outer surface is
fitted with the central hole 121 having an uniform inner diameter,
the wall of the bush 2 will be gradually restricted by the central
hole 121 and radially deformed to shrink during a process of
rotating the bush 2 toward a first direction (for example,
clockwise) into the central hole, and thus to reduce the inner
diameter of the shaft hole 20 until the flange 24 abuts against a
lower edge of the hub 12. In contrast, when rotating the bush 2
toward a second direction (for example, counterclockwise), the wall
of the bush 2 restricted by the central hole 121 will be gradually
released and radially expanded while the bush 2 gradually rotates
out of the central hole 121, and thus enlarge the inner diameter of
the shaft hole 20.
[0036] Therefore, when assembling the foot ring 1 on the supporting
post 3, the bush 2 should be rotated firstly and moved outward from
the central hole 121 for enlarging the inner diameter of the shaft
hole 20 to allow the supporting post 3 to penetrate through, and
then insert the supporting post 3 into the shaft hole 20, and then
rotate and move the bush 2 inward the central hole 121. As
described above, the shaft hole 20 will be shrunk during the
movement of the bush 2 into the shaft hole 20, and thus the inner
diameter of the shaft hole 20 is decreased to clamp and fix the
supporting post 3, as shown in FIGS. 6 to 7. In particular, since
the soft pads 23 provided on the shaft hole 20 protrudes from the
inner surface of the shaft hole 20, the pads 23 will be compressed
to deform during the process of clamping the supporting post 3 with
the shaft hole 20 of the bush, so that the supporting post 3 can be
supported and clamped by the pads 23 with a higher friction
coefficient. Similarly, when needing the adjustment of the foot
ring 1 to other height positions, the bush 2 is rotated to release
the clamping on the supporting post 3, as shown in FIG. 8, the foot
ring 1 can be moved upward and downward along the supporting post
3, and then the bush 2 is rotated toward a reverse direction to fix
it on the supporting post 3 after a desired height position is
reached.
[0037] The above description is only for explaining the preferred
embodiments of the present invention, and is not intended to limit
the present invention. Therefore, any form of the changes should be
included in the scope of the invention as claimed.
* * * * *