Movable backrest of an adjustable chair

Abstract

The invention is directed to a movable backrest of an adjustable chair, which can include: a backrest assembly, a first backrest support, a first backrest connector, a second backrest support, a second backrest connector, and a backrest guiding apparatus; the backrest assembly is connected to the first backrest support through a first shaft, the backrest assembly is connected to the guiding apparatus through a seventh shaft, the first backrest support is connected to the first backrest connector through a second shaft, the backrest guiding apparatus is connected to the first backrest connector through a sixth shaft. The invention is simple, durable, and easy to operate, can help eliminate a gap between the backrest and the sitting pad when the adjustable chair is at different positions, reduce the friction feeling of a person's back and prevent the backrest from touching the well when the adjustable chair is at different positions.

Claims

1. A movable backrest for an adjustable chair, comprising: a backrest assembly; a first backrest support; a first backrest connector; a second backrest support; a second backrest connector; and a backrest guiding apparatus; wherein the backrest assembly is connected to the first backrest support through a first shaft, the backrest assembly is connected to the backrest guiding apparatus through a seventh shaft, the first backrest support is connected to the first backrest connector through a second shaft, the backrest guiding apparatus is connected to the first backrest connector through a sixth shaft, the second backrest support is connected to the first backrest connector through a third shaft, the second backrest connector is connected to the backrest guiding apparatus through a fifth shaft, and the second backrest support through a connection with a fourth shaft forms a cross with the second backrest connector, wherein the third shaft is disposed at a first end of the first backrest connector, the sixth shaft is disposed at a second end of the first backrest connector, the second end being opposite the first end, and the second shaft is disposed between the third shaft and the sixth shaft.

2. The moveable backrest of claim 1, wherein centerlines of the first shaft, the second shaft, the sixth shaft, and the seventh shaft form a parallelogram.

3. The moveable backrest of claim 1, wherein the backrest guiding apparatus has a position-limiting rivet.

4. The moveable backrest of claim 2, wherein the backrest guiding apparatus has a position-limiting rivet.

5. An adjustable chair, comprising: a sitting pad, a movable backrest, and an extendable footrest, wherein the movable backrest includes: a backrest assembly; a first backrest support; a first backrest connector; a second backrest support; a second backrest connector; and a backrest guiding apparatus; wherein the backrest assembly is connected to the first backrest support through a first shaft, the backrest assembly is connected to the guiding apparatus through a seventh shaft, the first backrest support is connected to the first backrest connector through a second shaft, the backrest guiding apparatus is connected to the first backrest connector through a sixth shaft, the second backrest support is connected to the first backrest connector through a third shaft, the second backrest connector is connected to the guiding apparatus of the backrest through a fifth shaft, and the second backrest support through a connection with a fourth shaft forms a cross with the second backrest connector, wherein the third shaft is disposed at a first end of the first backrest connector, the sixth shaft is disposed at a second end of the first backrest connector, the second end being opposite the first end, and the second shaft is disposed between the third shaft and the sixth shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side view of one embodiment of the invention.

(2) FIG. 2 is a side view of the embodiment in the first state, where a backrest assembly has the same angle as the original backrest.

(3) FIG. 3 is a side view of the embodiment in the second state, where a footrest is extended.

(4) FIG. 4 is a side view of the embodiment in the third state, where the backrest has a space with a wall and has a similar angle as the original backrest.

(5) FIG. 5 illustrates a present sofa chair design and its position changes during usage.

DETAILED DESCRIPTION

(6) The invention is further described with the accompanying drawings and exemplary embodiments.

(7) The embodiment of a movable backrest of an adjustable chair include a backrest assembly 1, a first backrest support 2, a first backrest connector 3, a second backrest support 4, a second backrest connector 5, and a backrest guiding apparatus 6. The backrest assembly 1 is connected to the first backrest support 2 through a first shaft A, the backrest assembly 1 is connected to the backrest guiding apparatus 6 through a seventh shaft I, the first backrest support 2 is connected to the first backrest connector 3 through a second shaft B, the backrest guiding apparatus 6 is connected to the first backrest connector 3 through a sixth shaft H. Movements and swing angles of backrest assembly 1 can be controlled by the backrest assembly 1, the first backrest support 2, the first backrest connector 3 and the guiding backrest apparatus 6 through the first shaft A, the second shaft B, the sixth shaft H, the seventh shaft I, so that desired movements and lying angles of the backrest of the adjustable chair can be achieved. Centerlines of the first shaft A, the second shaft B, the sixth shaft B and the seventh shaft I respectively are configured to form a parallelogram ABHI, (see FIG. 1), which can help achieve a relatively easy adjustment and a relatively large adjustment range. The second backrest support 4 is connected to the first backrest connector 3 through a third shaft C, the second backrest connector 5 is connected to the backrest guiding apparatus 6 through a fifth shaft G, the second backrest support 4 and the second backrest connector 5 forms a cross and are connected through a fourth shaft F. A displacement caused by unfolding the adjustable chair can drive the second backrest support 4 and the second backrest connector 5 to open so as to drive the first backrest connector 3 and the backrest guiding apparatus 6 to open and result in a displacement. As a result, an upper portion of the backrest moves downwardly and a lower portion of the backrest move forwardly (the left side in the drawing is the forward direction), which can help eliminate a movement of the backrest relative to a person's back.

(8) The embodiment also includes a position-limiting rivet J on the backrest guiding apparatus 6, which can be used to support and limit the position of the adjustable chair when the adjustable chair is lying down, increasing the stability of the backrest.

(9) In the illustrated embodiment, the second backrest support 4 is connected to a driving device of the adjustable chair through a ninth shaft E, and the second backrest connector 5 is connected to the driving device of the adjustable chair through an eighth shaft D, which can be used to link a movement of a person's back to a movement of the driving device of the adjustable chair.

(10) When the backrest of the adjustable chair illustrated herein is in a sitting state (i.e. in the state as illustrated in FIG. 2), the driving device (which is similar to a conventional design) of the adjustable chair is in a folded position. As the adjustable chair unfolds, the driving device can have a displacement through the eighth shaft D and the ninth shaft E. Therefore, the backrest retains the original angle and moves synchronously with a footrest driving device (i.e. in the state as illustrated in FIG. 3). As the adjustable chair continues to unfold, the eighth shaft D and the ninth shaft E gradually opens, causing the shaft F to rotate and drive the third shaft C and the shaft G to open. Then, the sixth shaft H and the fourth shaft F move closer and drive the backrest connector 3 to rotate downwardly. The downwardly rotation of the backrest connector 3 can also drive the second shaft B so as to drive a downward movement of the first backrest support 2. At the same time, due to the movements of the sixth shaft H and the second shaft B, an angle between the first backrest connector 3 and the first backrest support 2, the backrest guiding apparatus 6 reduces, causing the seventh shaft I and the second shaft B to move closer. These movements cause the backrest to move forwardly. The backrest assembly 1, due to a relatively small displacement of the first shaft A on the first backrest support 2 and a relative large displacement of the seventh shaft on the backrest guiding apparatus, changes its angle. As a result, the backrest assembly 1 can gradually lean backwardly and reach the lying state (i.e. the state as illustrated in FIG. 4). When fully unfolded, the position-limiting rivet 6 on the guiding apparatus 6 can bear the first backrest support 3, increasing the stability of the backrest.

(11) This invention can help eliminate a gap between the backrest and the sitting pad when the adjustable chair is at different positions, reduce friction feeling on a person's back and prevent the backrest from touching the well when the adjustable chair is at different positions. The invention is simple, durable, and easy to operate. The backrest can be driven by changing the states of the adjustable chair.

(12) Any modification or equivalent substitution according to the present invention, should be considered to fall within the protection scope of the present invention.