A method for manufacturing a backrest and/or having a textile covering or the same, and mounted on a chair tubular chassis or the same includes the following steps:

folding the lateral edges of the textile covering and seaming the edges to form lateral sheaths by lateral seam line,

affixing at least three visual markers, (notches), to at least one of the ends of each of the lateral sheaths, a first central notch at the lateral edge of each of sheaths and two peripheral notches on both sides of the respective central notch,

folding the free ends of the sheaths by fitting each central notch between the respective peripheral notches, such that the notches extend facing each other,

seaming the free ends of the sheaths at the folding area of the notches by a transverse seam line, and

turning over the textile covering by bringing out the corners.

Provided is a chair including a support member that is at least a seat body and a backrest to support an occupant. The support member includes a composite portion at least a part of an outer periphery of the support member. The composite portion includes a first outer periphery that is a part of the first member and a second outer periphery that is a part of the second member. The first outer periphery and the second outer periphery are arranged to overlap each other in a thickness direction of the support member. In the composite portion, at least a part of the first outer periphery is formed into a thin portion thinner in the thickness direction than a part located on an outside of at least the part of the first outer periphery in the first member.

Provided is a chair including a support member that is at least a seat body and a backrest to support an occupant. The support member includes a composite portion at least a part of an outer periphery of the support member. The composite portion includes a first outer periphery that is a part of the first member and a second outer periphery that is a part of the second member. The first outer periphery and the second outer periphery are arranged to overlap each other in a thickness direction of the support member. In the composite portion, at least a part of the first outer periphery is formed into a thin portion thinner in the thickness direction than a part located on an outside of at least the part of the first outer periphery in the first member.

A method for manufacturing a backrest and/or having a textile covering or the same, and mounted on a chair tubular chassis or the same includes the following steps: folding the lateral edges of the textile covering and seaming the edges to form lateral sheaths by a lateral seam line, affixing at least three visual markers, (notches), to at least one of the ends of each of the lateral sheaths, a first central notch at the lateral edge of each of the sheaths and two peripheral notches on both sides of the respective central notch, folding the free ends of the sheaths by fitting each central notch between the respective peripheral notches, such that the notches extend facing each other, seaming the free ends of the sheaths at the folding area of the notches by a transverse seam line, and turning over the textile covering by bringing out the corners.

A method for manufacturing a backrest and/or having a textile covering or the same, and mounted on a chair tubular chassis or the same includes the following steps: folding the lateral edges of the textile covering and seaming the edges to form lateral sheaths by a lateral seam line, affixing at least three visual markers, (notches), to at least one of the ends of each of the lateral sheaths, a first central notch at the lateral edge of each of the sheaths and two peripheral notches on both sides of the respective central notch, folding the free ends of the sheaths by fitting each central notch between the respective peripheral notches, such that the notches extend facing each other, seaming the free ends of the sheaths at the folding area of the notches by a transverse seam line, and turning over the textile covering by bringing out the corners.

Provided is a chair including a support member that is at least a seat body and a backrest to support an occupant. The support member includes a composite portion at least a part of an outer periphery of the support member. The composite portion includes a first outer periphery that is a part of the first member and a second outer periphery that is a part of the second member. The first outer periphery and the second outer periphery are arranged to overlap each other in a thickness direction of the support member. In the composite portion, at least a part of the first outer periphery is formed into a thin portion thinner in the thickness direction than a part located on an outside of at least the part of the first outer periphery in the first member.

A joint assembly that includes first and second joint members is provided. The joint assembly includes a reinforcing member that has an outer surface that defines a plurality of cavities. Foam is located in the joint members and engages the reinforcing member such that the foam is located in the cavities of the reinforcing member. Additionally or alternatively, the joint assembly may be constructed so that the inner surface of the first joint member defines a plurality of cavities. Foam is located in the joint members and engages the inner surface of the first joint member so that it is located in the cavities of the first joint member. Various methods of manufacturing and treating the joint assembly are also provided.

A joint assembly that includes first and second joint members is provided. The joint assembly includes a reinforcing member that has an outer surface that defines a plurality of cavities. Foam is located in the joint members and engages the reinforcing member such that the foam is located in the cavities of the reinforcing member. Additionally or alternatively, the joint assembly may be constructed so that the inner surface of the first joint member defines a plurality of cavities. Foam is located in the joint members and engages the inner surface of the first joint member so that it is located in the cavities of the first joint member. Various methods of manufacturing and treating the joint assembly are also provided.