Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: AN ADJUSTING APPARATUS FOR T~ BACKREST OF A
CHAIR
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to the backrest of a chair, and in particular
to an adjusting apparatus for use to adjust the backrest to conform with and
to
support the spinal cord of the different users.
(b) Brief Description of the Prior Art
As the body structure for everyone is different, the shape of curvature
of the spinal cord for each one is also different. Conventional chairs with
backrest to support the back or spinal cord of the user are normally not
adjustable in order to suit everyone. Most of the time, the backrest provides
no function to the users in supporting the backbone of the body for the reason
that the backrest is not designed with respect to ergonomic engineering.
Even some backrests of chairs are designed ergonomically, these backrests
cannot suit everyone for the reasons that these backrests cannot be adjusted
to
fit the curvature of the spinal cord of all users. Accordingly, it is a main
object of the present invention to provide an adjusting apparatus for the
backrest of a chair, which can adjust the curvature of the backrest to suit
the
spinal cord of the users.
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SLIPvIMARY OF THE PRESENT INVENTION
In order to overcome the disadvantages of conventional backrest, the
present invention provides an adjusting apparatus for the backrest of a chair
comprising an adjusting member connected to and controlled the backrest, a
backrest board body having a top and bottom ends at the sides thereof, rails
slidably inserted into the backrest, a first guiding cable connected to the
top
and bottom ends of the board body, a second and a third guiding cables being
respectively secured at one end of the board body, thereby the adjusting of
the
first cable by means of the adjusting member causes the board body to bend or
curve, and to release the second and third guiding cable causes an up and
down displacement of the board body with respect to the rails, and the board
body is adjusted to comfortably support the user in a laying position.
It is an object of the present invention to provide an adjusting apparatus
for the backrest of a chair, wherein the board body is closely with the spinal
cord of the user by means of the first guiding cable, thereby the back of the
user lying on the backrest is sufficient supported.
A further object of the present invention is to provide an adjusting
apparatus for the backrest of a chair, wherein the height of the backrest can
be
adjusted by the use of the second and the third guiding cable, thereby the
support position to the user can be adjusted based on the sitting posture of
the
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user.
Other objects as well as the numerous advantages of the adjusting
apparatus for the backrest of a chair in accordance with the present invention
will become apparent from the following detailed description and the
accompanying drawing, in which:
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BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is a perspective view of the adjusting apparatus for the backrest
of a chair in accordance with the present invention.
Fig. 2 is a perspective exploded view of the adjusting member for the
backrest of a chair in accordance with the present invention.
Fig. 3 is a schematic plan view of the adjusting apparatus for the
backrest of a chair in accordance with the present invention.
Fig. 4 is a schematic view showing the bending curvature in
accordance with the present invention.
Fig. S is a schematic view showing the up down adjustment of the
adjusting apparatus in accordance with the present invention.
Fig. 6 is a sectional view of another adjusting apparatus for the backrest
of a chair in accordance with the present invention.
Fig. 7 is a schematic plan view of the adjusting member for the
backrest of a chair in accordance with the present invention.
Fig. 8 is a perspective exploded view of the another adjusting member
for the backrest of a chair in accordance with the present invention.
Fig. 9 is a sectional view of the adjusting member for the backrest of a
chair in accordance with the present invention.
Fig. 10 is a schematic plan view showing the adjustment of
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displacement of for the bacla~est of a chair in accordance with the present
invention.
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DETAILED DESCRIPTION OF TIC PRESENT INVENTION
Referring to Fig. 1 of the present invention, there is shown an adjusting
apparatus for the bacla~est of a chair comprising a bacl~est board body 1
having a top and bottom ends at the sides thereof and the board body 1 is a
flexible board body which is slightly curved, a rail 2 slidably inserted into
the
baclffest and a first guiding cable 4 is connected to the top and bottom ends
of
the two lateral sides of the board body 1. A second and a third guiding cable
5, 6 are respectively secured in opposite direction to a securing end on the
board body 1. Thus, the adjusting of the first cable 4 in its length by means
of an adjusting member causes the board body to bend or to curve, and the
releasing of second and third guiding cable S, 6 causes the up and down
displacement of the board body 1 with respect to the rails 2, thereby the
board
body 1 can be adjusted to a position to comfortably support the users.
In accordance with the present invention, the board body 1 is a flexible
curved board body, having the top and bottom ends of the two sides thereof
are provided with holes 11, and an extension board 12 with a first slot 13 is
provided to the corresponding top and bottom ends. The extension board 12
is provided with two corresponding second 14 and third slot 15 and a
mounting member 16 for the guiding cables.
In the preferred embodiment; the rail 2 is a long rod body inserted within
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a hole 11, and the adjusting member 7 (as shown in Fig. 2) is a threaded rod
71
with a nut 72 which is inserted into a housing body 73 for the adjusting of
cables. A U-shaped peg 78 is clipped at the two sides of the neck portion of
the screw rod 71, and one side of the housing body 73 is protruded with a
S spring disc 74 for the mounting of a swinging engagement gear 75 to
correspond to a fan-like teeth 77 within an adjusting nut 76. A sound is
produced when the adjusting nut 76 is adjusted
As shown in Fig. 3, a pad 21 is used to mount the ends of the rails onto
the backrest 3 via the hole 11 on the board body 1 such that the rail 2 is
kept a
distance from the backrest 3. The two adjusting members 7 are respectively
mounted to the first and the second guiding cables 4,5 and the guiding tube of
the first guiding cable 4 urges the mounting portion 16 of the board body 1.
The other end of the guiding cable is located within the first slot 13 and the
guiding protrusion of the second guiding cable 5 is adapted at the second slot
14, and the guiding cable protrusion of the third guiding cable 6 is located
within the third slot 15, and the end terminal of the third guiding cable 6 is
connected from one end to the other end of the spring 8 mounted on the
backrest 3. Finally, the two adjusting members 7 are mounted onto the seat.
In accordance with the present invention, when the first guiding cable 4 is
pulled via the adjusting member 7, the exposed length of the first guiding
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cable 4 is changed and the straight distance at the two ends of the board body
1 will correspondingly change. Thus, when the straight distance of the two
ends of the board body is shorter, the curvature of the board body 1 is larger
(as shown in Fig. 4). When the straight distance of the two ends of the
board body 1 is longer, the curvature of the board body 1 is smaller. Thus,
the curvature of the board body 1 is adjusted to comfortably suit the user.
When the adjusting member 7 releases the second guiding cable 5, the spring
8 of the third guiding cable 6 will react in accordance with the guiding cable
5.
When the second guiding cable 5 is pulled towards the board body 1, the
board body 1 will move upward along the rails 2. Otherwise, when the
second guiding cable 5 is released, the spring 8 causes the third guiding
cable
6 to be pulled and the board body 1 will move downward along the rails.
The control of the board body 1 will correspondingly control the position of
the backrest 3 (as shown in Fig. 5). As a result, the backrest 3 can be
adjusted to suit the sitting posture of the user in order to provide a comfort
sitting.
As shown in Fig. 6, the adjusting member 7 comprises the screw nut 72
mounted to the screw rod 71 such that the second and the third guiding cables
5, 6 are engaged in opposite direction. When the adjusting nut 76 is adjusted,
the up and down movement of the board body 1 is adjusted (as shown in Fig.
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7).
In order to allow smooth operation of the second and the third guiding
cables S, 6m a pulley 22 is located at the turning point on the board body l,
and the end terminal of the guiding tube of the second and third guiding
cables
5, 6 are mounted on an adjusting seat 23, such that during installation, the
exposed length of the cables 5, 6 can be adjusted
Figs. 8 and 9 are further embodiments of the present invention. There is
shown the adjusting nut 76 is connected to a rod 761 and pivotally mounted to
the housing body 73 such that the nut 76 can move in axial direction. The
rod 761 further mounted with a main gear 762 having a screw rod 71
connected to a driven gear 711 and a screw nut 72 at the front and rear sides
of
the main gear 762. There are slots 79 provided to the screw nut 72. When
the adjusting member 7 is used to adjust the board body l, the second and the
third guiding cables S, 6 are respectively mounted to the board body 1 via the
slots 79. The screw nut 72 of the screw rod 71 is used for the first guiding
cable 4 to be connected to the board body 1. Thus the adjusting of the board
body 1 will move the driven gear 711 of the screw rod 71 con esponding to the
adjusting of the main gear 762 of the adjusting nut 76. Thus, the curvature of
position of the board body 1 is adjusted (as shown in Fig. 9).
The pivotal position of the rod 761 of the adjusting member 7 on the
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housing body 73 is provided with a steel bead 731 with spring force, and a
recess 763 is provided on the rod 761 corresponding to the driven gear 711
such that the recess 763 can hold a steel bead 731 as a positioning force to
avoid the dislocation of the adjusting nut 76.
S The interior of the housing 73 of the adjusting member 7 is provided with
a pulley 732 at the turning point of the guiding cable so as to minimize
frictional force between the guiding cable and the housing body 73.
In another preferred embodiment, an electrical control motor 70 is
provided to the end of the rod 761 of the adjusting nut 76, and a plurality of
10 sensors 721 are mounted to the rod 761 of the adjusting nut 76 and the
screw
nut 72. The distance between two corresponding driven gear 711 of the
housing body 73 and the dead points at the up and down position of the
moving space of the screw nut 72 are provided with sensing plates 722 to
connect to an IC board. The motor 70 is controlled by a switch 701.
Accordingly, before the switch 701 is pressed, the adjusting member 7 is kept
manual control. When the switch 701 is pressed, the corresponding screw
nut 72 of the corresponding adjusting nut 76 is proceeded to transmission (as
shown in Fig. 10)
The rails 2 for the up and down movement of the board body 1 are
provided with a plurality of wheels within guiding slots so as to guide the
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board body 1.
It will be appreciated that the foregoing is considered as illustrative
only of the principles of the invention and numerous modification and changes
will readily occur to those skilled in the art, it is not desired to limit the
invention to the exact method described, and accordingly, all suitable
modification and equivalents may be resorted to, falling within the scope of
the invention.
