Chair backrest

Abstract

Provided is a two-sectional ergonomic chair backrest comprising a vertical backrest support, an upper back unit releasably secured to the backrest support, a waist unit including a front waist member, an intermediate frame, and a rear plate releasably secured to the backrest support, and a bent, resilient connecting member including a lower portion releasably secured to the waist member and the frame, and an upper portion releasably secured to the backrest support such that in response to the waist of a seated person urged against the waist unit, the connecting member is elastically deformed so as to provide a great degree of comfort to the waist.

Description

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to ergonomic chair backrests and more particularly to such a backrest consisting of two cooperative waist and back sections so as to bring a degree of comfort to, particularly the waist of a seated person.

2. Related Art

A conventional chair backrest is a one-piece component. Also, most prior art ergonomic chair backrests emphasize the degree of comfort to the back of a seated person rather than the waist. A small number of prior art chair backrests incorporating a mechanism for bringing a degree of comfort to the waist of a seated person. However, such prior mechanisms cannot fit waists of different seated people. Thus, backrests with height-adjustable waist pads are developed, in which a waist pad is attached to a backrest of a chair by elastic bands. However, such conventional art suffers from some disadvantages. For example, elastic bands ultimately lose its elasticity. Another conventional backrest is provided with a waist support cooperated with a transmission member. Such conventional backrests are typically, relative complex in constructions and costly to manufacture. Hence, a need for improvement still exists.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a two-sectional ergonomic chair backrest which has simply constructions and structures.

The chair backrest according to the present invention comprises a vertical backrest support; an upper back unit formed of an elastomeric material and releasably secured to the backrest support; a waist unit including a front waist member formed of an elastomeric material, an intermediate frame, and a rear plate releasably secured to the backrest support, and a bent, resilient connecting member including a lower portion releasably secured to the waist member and the frame, and an upper portion releasably secured to the backrest support. By utilizing this chair backrest, in response to the waist of a seated person urged against the waist unit, the connecting member is elastically deformed so as to provide a great degree of comfort to the waist.

In one aspect of the present invention, the backrest support comprises a plurality of upper hollow locating cylinders, and the back unit comprises a plurality of rear pegs shaped to neatly insert into the locating cylinders for fastening.

In another aspect of the present invention, the frame comprises a plurality of peripheral locating holes, and the plate comprises a plurality of peripheral hollow locating cylinders shaped to neatly insert into the locating holes for fastening.

In yet another aspect of the present invention, the upper portion of the connecting member is disposed in a recess between the back unit and the backrest support, and the lower portion of the connecting member is disposed in a recess between the frame and the plate.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a preferred embodiment of a chair backrest according to the invention;

FIG. 2 is a perspective view of the assembled backrest of FIG. 1;

FIG. 3 is a side view of the backrest of FIG. 2 assembled with a chair;

FIG. 4 is a front view of the backrest of FIG. 2;

FIG. 5 is a schematic sectional view taken along sectional line I of FIG. 4; and

FIG. 6 is a view similar to FIG. 5, where a force is exerted onto the waist unit and the connecting member is elastically deformed in response.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, there is shown a chair backrest constructed in accordance with a preferred embodiment of the invention. The backrest comprises a waist unit 1, a bent, resilient connecting member 2, an upper back unit 3 and a substantially rectangular, vertical backrest support 4 and a plurality of fasteners 5 such as screws or the like.

The waist unit 1 includes a front waist member 11 formed of an elastomeric material, an intermediate, rectangular frame 12 having a plurality of locating holes 122 on its periphery and a plurality of apertures 121 in its upper, central portion, and a rear, rectangular plate 13 having a plurality of hollow locating cylinders 131 shaped to neatly insert into the locating holes 122 for fastening.

The upper back unit 3 includes a front backrest member 31 formed of an elastomeric material, and a curved rear portion 32 having a plurality of pegs (not shown) shaped to neatly insert into the locating cylinders 43.

The backrest support 4 is formed integrally and includes, from top to bottom, a plurality of hollow locating cylinders 43 arranged on the upper and side edges of an upper section, a projection 41, a plurality of threaded holes 42 arranged as a shape of rectangle around the projection 41, and a forwardly projected bracket 44.

The bent, resilient connecting member 2 includes a plurality of threaded holes, an upper portion disposed in a recess of the upper section of the backrest support 4, and a lower portion disposed in a recess behind the frame 12 and fastened between the frame 12 and the plate 13 by screwing fasteners 5 through apertures on the lower portion of the connecting member 2 into the apertures 121 and by inserting locating cylinders 131 of the plate 13 into the locating holes 122 of the frame 12.

In assembly, referring to FIGS. 1 and 3, the projection 41 is neatly inserted into a central hole of the connecting member 2 attached to the waist unit 1 for positioning. The plurality of fasteners 5 are secured through apertures on the upper portion of the connecting member 2 to the holes 42 of the backrest support 4 for fastening. In addition, pegs of the back unit 3 are inserted into the hollow locating cylinders 43 so that the back unit 3 and the backrest support 4 are assembled together. The forwardly projected bracket 44 is secured to a bottom of a seat in a manner well known in the art.

Referring to FIGS. 3, 4, 5, and 6, in response to the waist of a seated person urged against the waist unit 1 as indicated by arrows, the connecting member 2 is elastically deformed. As a result, a great degree of comfort to the waist of the person is brought by the ergonomic waist unit 1.

While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.

Claims

1. A chair backrest comprising:

a vertical backrest support;

an upper back unit formed of an elastomeric material and releasably secured to the backrest support;

a waist unit including a front waist member formed of an elastomeric material, an intermediate frame, and a rear plate releasably secured to the backrest support, and

a bent, resilient connecting member including a lower portion releasably secured to the waist member and the frame, and an upper portion releasably secured to the backrest support.

2. The chair backrest of claim 1, wherein the backrest support comprises a plurality of upper hollow locating cylinders, and the back unit comprises a plurality of rear pegs shaped to neatly insert into the locating cylinders for fastening.

3. The chair backrest of claim 1, wherein the frame comprises a plurality of peripheral locating holes, and the plate comprises a plurality of peripheral, hollow locating cylinders shaped to neatly insert into the locating holes for fastening.

4. The chair backrest of claim 1, wherein the upper portion of the connecting member is disposed between the back unit and the backrest support, and the lower portion of the connecting member is disposed between the frame and the plate.