Chair backrest frame with corner connectors at the bottom

Abstract

The utility model relates to the field of office and domestic furniture, and more particularly to devices for creating comfort during prolonged sitting at a computer and for preventing musculoskeletal disorders. A frame for a backrest of a chair comprises lateral members, a transverse connecting member, and corner connectors. The corner connectors are disposed at the bottom of the backrest frame, and more particularly at the junction between the lateral members and a base.

Description

[0001] Chair back frame with gusset at the bottom

[0002] The utility model relates to the field of office and home furniture, namely to devices for creating comfort during prolonged work at a computer and for the prevention of diseases of the musculoskeletal system.

[0003] As a rule, office chair manufacturers use plastic, metal or wood as the source material for the main components of the chair: the back, seat, headrest and armrest.

[0004] As a rule, either expensive products or cheap ones with very limited functionality are made from wood.

[0005] Manufacturing plastic chair components requires the development of specialized molds and machines to cast plastic parts into these molds. This is an expensive process, requiring a huge market to reduce its cost. It also makes it impossible to create unique, distinctive products.

[0006] The use of metal semi-finished products for the manufacture of chair parts expands their range, allowing them to be manufactured in various configurations in small quantities at a low cost.

[0007] To produce the backrests of metal-framed office chairs, tubing of various profiles, sizes, and wall thicknesses is widely used. To achieve the desired backrest profile, the tubing is bent. These bends are made with a specific radius and tubing thickness to prevent kinks and flattening, as well as to prevent the backrest from unbending during use. Consequently, office chair manufacturers are forced to compromise, either increasing costs by using thicker tubing or reducing functionality by eliminating certain components. Typically, the lower portion of an office chair backrest made from metal tubing bears the heaviest loads. To ensure this area withstands these loads, thick-walled tubing is used, the lower bend is made with a larger radius, and additional reinforcements are added to the tubing.

[0008] A connection unit for support elements is known (RU 14620 U1, IPC F16B 12 / 44, published 10.08.2000) containing at least one post with an opening for the passage of a fastening element, two crossbars, a bracket, characterized in that the bracket is made in the form of a bracket with projections entering slots made in the crossbars, and an opening for fixing the fastening element.

[0009] The disadvantage of this solution is that a third element is needed to fix the other two relative to it.

[0010] A corner joint unit for a furniture frame is known (RU 2438547 C1, IPC A47B 13 / 00, F16B 12 / 44, published 10.01.2012) consisting of two parts, at least one of which is a cylindrical pipe, pulled together by at least one threaded element passing through a bookmark installed inside the pipe, characterized in that the bookmark consists of three plates, one of which is parallel to the axis of the pipe, the other two plates are attached by their edges to the plane of the first plate and are in contact with the walls of the pipe, the threaded element passes through an opening in the first plate between the other two, the unit is provided with a fastening element with at least one threaded hole for the threaded element.

[0011] The disadvantage of this solution is the complexity of the design and limited use.

[0012] A seat frame is known (RU 214537 U1, IPC B60N 2 / 427, B60N 2 / 68, published on 02.11.2022) forming a backrest and a base, which is a tubular structure made with the possibility of elastic and residual deformation of a part of the backrest, and including a limiter of this residual deformation, characterized in that the limiter is made in the form of gussets, each of which is rigidly attached to the frame tube in the lower part of the backrest and has a protruding part with a rectilinear edge facing the base, allowing the rotation of the backrest part during deformation until it stops against the lower part of the frame at an angle of 15-35°.

[0013] The disadvantage of this solution is the metal consumption of the structure and the ability to work in only one direction.

[0014] The technical challenge is to be able to use a thinner metal pipe when making the back frame, as well as to eliminate the lower radius bend from the back frame design.

[0015] The technical result is achieved by using a gusset in the lower part of the backrest frame during its manufacture, namely, by fixing the gusset to the base and to the tubular backrest frame, which is also secured to the base, which allows the bending load on the backrest frame in this part to be changed to a compression load, while the gusset bears the tensile load.

[0016] The essence of the utility model is explained by drawings.

[0017] Fig. 1 shows the back frame in projection / from the front.

[0018] The back frame contains side panels 1 and 2, secured to each other by a crossbar 3 at the top, and fixed at the bottom on bases 4 and 5, respectively, and also connected to each other by gussets 6 and 7.

[0019] The term "sides" refers to the vertically oriented parts of the back frame connected to each other by a crossbar, between which the upholstery is installed.

[0020] In this case, a pipe is used as side members 1 and 2, and a plate is used as crossbar 3. Another design option uses a single piece of pipe serving as the side members and crossbar, fabricated using radius bends in the required planes to achieve the desired backrest frame configuration. In this design, a pipe is used as bases 4 and 5. Other implementations of this solution could use a plate or other profile (such as an angle or channel).

[0021] Gussets 6 and 7 in this design use a plate with curved ends to increase the contact area. Alternatively, several plates can be used as gussets, positioned side by side or at a certain distance from each other, as well as at different angles relative to each other, both vertically and horizontally.

[0022] In this embodiment, sidewalls 1 and 2, bases 4 and 5, and gussets 6 and 7 are welded together. However, an alternative is to have gussets 6 and 7 bolted to sidewalls 1 and 2 and bases 4 and 5, and sidewalls 1 and 2 installed in a groove in bases 4 and 5, or to have a boss formed on bases 4 and 5, onto which sidewalls 1 and 2 are mounted along the inner surface of the pipe.

[0023] When constructing the backrest frame in all of the above-mentioned designs, it is possible to use a tube with a thinner wall thickness, since the bending loads that occur at the bottom of the backrest when a person sits and leans against it are replaced in this design by compression loads exerted by sections of side panels 1 and 2 in these areas, while gussets 6 and 7 support tensile loads. These designs also eliminate the need for a radius bend at the bottom of the backrest to extend side panels 1 and 2 as bases 4 and 5.

Claims

Formula 1. The frame of the back of the chair consists of a crossbar and side panels made of pipes, fixed to bases, on which gussets are also fixed, connected to the side panels at the bottom.

2. The frame of the back of the chair according to item 1, characterized in that the side, base and gusset are secured together by welding.

3. The frame of the back of the chair according to item 1, characterized in that the gusset is made in the form of several plates located next to or at a distance from each other.

4. The frame of the chair back according to item 3, characterized in that the plates are located at an angle to each other.

5. The frame of the back of the chair according to paragraph 1, characterized in that the gusset is secured to the side and the base by means of a bolted connection, and the side is fixed to a groove or protrusion formed on the base.

6. The frame of the back of the chair according to item 1, characterized in that the side panels and the crossbar are made from a single piece of pipe by means of bends in the required planes.

Images