HK1207807B - Chair with pivot function and method of making - Google Patents

Description

Chair with pivoting function and manufacturing method

Background

Many chairs, particularly office chairs, can be tilted backwards by weight actuation. That is, this means that the user can tilt the backrest portion of the chair to the reclining position by shifting his or her weight. The chair independently returns to its neutral position when the user shifts his/her weight back to the upright position or when the user leaves. This phenomenon is often described as "passive". When the user shifts his/her weight forward, the spring returns the back portion of the chair to its upright position. Some office chairs are arranged so that the seat portion also moves in response to the tilting of the backrest portion, and are commonly referred to as synchronized. Sometimes the seat portion is fixed to the backrest portion so that they pivot about the same angle, whereas in other chairs the seat portion is arranged to be lowered or raised at a different rate of inclination to that of the backrest portion, with the result that the backrest portion and the seat portion have different angular movements.

Disclosure of Invention

Some embodiments relate to a chair that includes a base, a hub, and a seat frame. The base is configured to support the chair on a surface. The hub is supported by the base and includes first and second side supports and first and second covers. The first side mount is positioned on a first side of the chair and includes a rear portion and a bottom portion. The second side mount is positioned on a second side of the chair and includes a rear portion and a bottom portion. The first cover is coupled to the first side mount to define a first channel with the first side mount. The second cover is coupled to the second side mount to define a second groove with the second side mount. The seat frame includes a first lateral member having a lower portion and an upper portion pivotally coupled to the rear portion of the first side mount and configured to be angled relative to the lower portion. The lower portion of the first lateral member is slidably received in the first channel such that both sides and a bottom of the lower portion received within the first channel are substantially hidden from view. The seat frame also includes a second lateral member having a lower portion and an upper portion pivotally coupled to the rear portion of the second side mount and configured to be angled relative to the lower portion. The lower portion of the second lateral member is slidably received in the second channel such that both sides and a bottom of the lower portion received within the second channel are substantially hidden from view.

Other embodiments relate to a chair including a first side mount positioned on a first side of the chair and having a rear portion extending substantially vertically and a bottom portion extending substantially horizontally and defining a first channel. The chair also includes a second side mount positioned on a second side of the chair and having a rear portion extending substantially vertically and a bottom portion extending substantially horizontally and defining a second channel. The seat frame of the chair includes a first lateral member including a lower portion and an upper portion connected to the lower portion such that the lower portion and the upper portion are configured to be angled with respect to each other. The lower portion of the first lateral member is slidably received in the first groove. The first groove defines a sliding surface and the lower portion of the first lateral member has a bushing slidably received against the sliding surface such that the lower portion of the first lateral member is vertically lifted as the upper portion of the first lateral member pivots rearward relative to the first side mount. The seat frame also includes a second lateral member including a lower portion and an upper portion coupled to the lower portion such that the lower portion and the upper portion are configured to be angled with respect to each other. The lower portion of the second lateral member is slidably received in the second groove.

Other embodiments relate to a chair including a seat frame including a first lateral member including a lower portion and an upper portion connected to the lower portion such that the lower portion and the upper portion are configured to be angled with respect to each other, the lower portion of the first lateral member being slidably received in a first channel of a first side mount of the chair. The chair also includes a second lateral member including a lower portion and an upper portion coupled to the lower portion such that the lower portion and the upper portion are configured to be angled with respect to each other. The lower portion of the second lateral member is slidably received in a second channel of a second side mount of the chair. The chair further includes means for vertically lifting the lower portion of the first lateral member and the lower portion of the second lateral member when the upper portion of the first lateral member and the rear portion of the first side mount are pivoted rearwardly together and means for supporting a user's weight between the first lateral member and the second lateral member.

Still other embodiments relate to a method of manufacturing a chair, the method comprising: the seat material is tensioned between a first lateral member having an upper portion and a lower portion and a second lateral member having an upper portion and a lower portion. Securing a rear cross member between the upper portion of the first side member and the upper portion of the second side member and securing a front cross member between the lower portion of the first side member and the lower portion of the second side member. Releasing the first and second side members onto first and second side mounts of a hub of a chair such that the first and second side mounts resist compression between the first and second side members.

While multiple embodiments are described, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Drawings

Fig. 1 is a perspective view of a chair according to some embodiments.

Fig. 2 is a perspective view of the chair of fig. 1 in a partially disassembled state, according to some embodiments.

Fig. 3 is a perspective view of a base and hub of the chair of fig. 1 with an opposing cover removed from the hub, according to some embodiments.

Fig. 4 is a perspective view of a seat frame of the chair of fig. 1 in a disassembled state, according to some embodiments.

Fig. 5 illustrates a side view of a portion of the chair of fig. 1 with the first cover removed, according to some embodiments.

FIG. 6 is an enlarged view of area 6-6 shown on FIG. 5, according to some embodiments.

Fig. 7 is an assembled view of seat frame 16 according to some embodiments.

Fig. 8 illustrates an engagement feature of a first lateral member of a seat frame of the chair of fig. 1 prior to engagement with a front cross member of the seat frame, in accordance with some embodiments.

Fig. 9 is a partial cross-sectional view illustrating the mating feature of fig. 8 mated with the front cross member after assembly of the front cross member and the first side member, according to some embodiments.

FIG. 10 illustrates a seat member of the chair of FIG. 1, according to some embodiments.

FIG. 11 is a cross-sectional view through the chair at line 11-11 in FIG. 1, according to some embodiments.

FIG. 12 is a perspective view of the seat frame of the chair of FIG. 1 secured to the hub of the chair prior to attachment of the cover, according to some embodiments.

Fig. 13 and 14 are illustrations of the tilt and lift functions of the chair of fig. 1 according to some embodiments, where fig. 13 shows the chair in an un-reclined state and fig. 14 shows the chair in a reclined state according to some embodiments.

Figure 15 illustrates another chair according to some embodiments.

Figure 16 shows another means for vertically lifting the lower portion of the side member when the upper portion of the side member is pivoted rearwardly.

Figure 17 illustrates another chair having a seat member including a mesh upper portion and a solid lower portion, according to some embodiments.

Figure 18 illustrates another chair having a seat member including a mesh upper portion and a solid lower portion, according to some embodiments.

Figure 19 illustrates another chair having a seat member including a solid upper portion and a solid lower portion with a gap therebetween to facilitate pivoting/tilting between the solid upper portion and the solid lower portion, according to some embodiments.

The drawings are exemplary in nature and should not be considered as exhaustive or limiting in scope.

Detailed Description

Fig. 1 is a perspective view of a chair 10 according to some embodiments. As shown, the chair 10 includes a base 12, a hub 14, a seat frame 16, and a seat member 18. Generally, the base 12 supports a hub 14 on a surface, the hub 14 retaining a seat frame 16, and the seat frame 16 in turn retaining a seat member 18. As shown in FIG. 1, the chair 10 defines a first side 22, a second side 24, a front 26, and a rear 28. As described subsequently, the chair 10 provides compact hidden tilt and lift features and efficient tensioned assembly features that facilitate easy assembly of the chair 10, although various additional or alternative features and advantages are contemplated according to various embodiments.

In some embodiments, the base 12 comprises a pedestal with casters (e.g., as shown in fig. 1) or without casters (e.g., as shown in fig. 15). The base 12 is formed of cast metal or other material as desired. In other embodiments, the base 12 may be any of a variety of fixed or mobile structures, including a base that is part of a stadium seat support (such as those found in movie theaters), an airplane seat support, an automobile seat support, or any of a variety of other seat supports. As shown in fig. 1, the base 12 includes a plurality of legs 30, casters 32 attached to the legs 30, and a height adjustment cylinder 34.

Fig. 2 is a perspective view of the chair 10 in a partially disassembled state, according to some embodiments. As shown, the hub 14 includes: a first side mount 42, the first side mount 42 positioned on the first side 22 of the chair 10; a second side mount 44, the second side mount 44 positioned on the second side 24 of the chair 10; a first cover 46, the first cover 46 configured to form a complementary fit with the first side mount 42; and a second cover 48, the second cover 48 configured to form a complementary fit with the second side support 44. The hub 14 is formed of cast metal or other material as desired.

As shown in fig. 2, the hub 14 further includes a first pair of struts 52 and a second pair of struts 54 that meet at a central portion 56, the first and second pairs of struts 52 and 54 and the central portion 56 generally defining a substantially X-shape. As shown, the struts 52, 54 and the center portion 56 couple the first and second side mounts 42, 44 together.

In some embodiments, the central portion 56 includes a through hole 62 and a groove 60 for receiving the height adjustment cylinder 34. The hub 14 further includes a height adjustment handle 58, the height adjustment handle 58 being generally substantially triangular in shape and including a fulcrum member 64, a cylindrical actuator 66 and a finger extension 68. The handle 58 is generally substantially triangular in shape and forms a complementary fit with and is received within the perimeter defined by the first pair of legs 52, the central portion 56 and the first side mount 42. The finger extension 68 is configured to be manipulated (e.g., pulled up or depressed) by a user to move the cylindrical actuator 66 to activate the height adjustment cylinder 34. Due to the complementary fit of the handle 58 and the surrounding portion of the hub 14, the handle 58 is largely hidden from view according to some embodiments.

Fig. 3 is a perspective view of the base 12 and hub 14 together with the covers 46, 48 removed from the hub 14, according to some embodiments. In some embodiments, the first side mount 42 and the second side mount 44 are substantially similar. Accordingly, when features are described in association with the first side mount 42, such description should be considered to also apply to corresponding features of the second side mount 44. In some embodiments, the first side mount 42 includes an inner wall 80 and a bottom wall 82, and defines a rear portion 84, a bottom portion 86, and a connecting portion 88.

As shown in FIG. 3, the first side mount 42 is generally L-shaped. The rear portion 84 extends substantially vertically and is angled relative to the bottom portion 86 (e.g., from about 20 degrees to about 160 degrees). In some embodiments, the rear portion 84 extends at an acute angle (e.g., about 63 degrees) relative to the bottom portion 86. The bottom 86 optionally extends substantially horizontally. In some embodiments, the bottom 86 is offset from a precise level (also described herein as "true level") relative to a horizontal surface (e.g., floor) on which the chair 10 is placed. For example, the bottom 86 may optionally be offset from true horizontal by about 0 degrees to about 45 degrees. As shown, for example, the bottom 86 is offset from true horizontal by approximately 6 to 12 degrees. The connecting portion 88 is substantially curved and extends between the rear portion 84 and the bottom portion 86.

As shown in FIG. 3, the rear portion 84 of the first side mount 42 defines a terminal end 90 with a pivot aperture 92 formed through the inner wall 80 positioned toward the terminal end 90. In some embodiments, the bottom portion 86 forms an angled sliding surface 100. In some embodiments, the angled sliding surface 100 is angled upward at about 15 degrees relative to the longitudinal axis X of the first side mount 42, although various angles (e.g., from about 0 degrees to about 30 degrees) are contemplated. The base 86 also includes a first fastener aperture 102 and a second fastener aperture 104. In some embodiments, the sliding surface 100 is substantially straight. In other embodiments, the sliding surface 100 is substantially curved or includes a straight section and a curved section (not shown).

In some embodiments, the first cover 46 and the second cover 48 are substantially similar. When features are described in association with the first cover 46, such description should be considered as pertaining to corresponding features of the second cover 48. As shown in fig. 2, the first cover 46 includes a rear portion 10, a bottom portion 112, a connecting portion 114 extending between the rear portion 110 and the bottom portion 112, and an armrest portion 116 extending from the rear portion 110.

In some embodiments, the first cover 46 has a shape that is substantially complementary to the first side mount 42. As shown in FIG. 2, the rear portion 110 has a substantially similar profile to the inner wall 80 at the location of the rear portion 84 of the first side mount 42 (FIG. 3). The base 112 has a substantially similar profile to the inner wall 80 at the base 86 (fig. 3). The junction 114 has a substantially similar profile to the inner wall 80 at the junction 88 (fig. 3).

As shown in fig. 2, the rear portion 110 includes a fastener post 120, the fastener post 120 configured to be received by the pivot aperture 92. The base 112 includes a first fastener post 122 and a second fastener post 124, the first fastener post 122 and the second fastener post 124 to be received by the first fastener aperture 102 and the second fastener aperture 104. As shown, the base 112 also includes a spring projection 126, the spring projection 126 for receiving a tension or compression spring.

Fig. 4 illustrates a perspective view of seat frame 16 in a disassembled state, according to some embodiments. The seat frame is optionally formed from a polymeric material (e.g., polypropylene), although a variety of other materials are contemplated. As shown, the seat frame 16 includes a first side member 130, a second side member 132, a front cross member 134, and a rear cross member 136. As shown, the seat frame 16 includes a sidebar (rider) groove 138, (also described as a sidebar groove) formed inward facing side and extending around the seat frame 16 in each of the first side member 130, the second side member 132, the front cross member 134, and the rear cross member 136. In some embodiments, the first and second lateral members 130, 132 are substantially similar. Accordingly, when features are described in association with the lateral member 130, such description should be considered as being applicable to corresponding features of the second lateral member 132.

As shown in fig. 11, the first lateral member 130 has a top 138A, a bottom 138B, a first side 138C, and a second side 138D, and includes an upper portion 140 and a lower portion 142. As shown in fig. 4, the upper portion 140 includes a corner section 146, a rear resting section 148, and a lower rear section 150, the corner section 146 being substantially rigid or generally inflexible under normal operating conditions. As shown, various portions of the first lateral member 130 are substantially complementary in shape to the first side mount 42 and the first cover 46. The corner section 146 has a side profile similar to the inner wall 80 of the first side mount 42 at the connection 88 (fig. 3). The lower rear section 150 has a similar side profile to the inner wall 80 at the rear 84 (fig. 3).

In some embodiments, the upper portion 140 of the first lateral member 130 includes a mating feature 152 to align the first lateral member with the rear cross member 136. As shown, the corner section 146 includes a tongue 154 for pivotally mating with the lower portion 142, and the rear rest section 148 includes a pivot aperture 156 through which the fastener post 120 of the first cover 46 is received.

As shown in fig. 4, the lower portion 142 of the first lateral member 130 includes a mating feature 158 to align the first lateral member with the front cross member 134. Fig. 5 illustrates a side view of the chair 10 with the cover 46 removed, according to some embodiments. As shown, the lower portion 142 of the first lateral member 130 has a side profile that is complementary to the bottom 86 of the first side mount 42, the lower portion 142 includes a groove (not shown) and a pivot aperture 160 for pivotally mating with the tongue 154, the first slot 162 is for receiving the first fastener post 122, the second slot 164 is for receiving the first fastener post 122 such that the first lateral member 130 has sufficient space to slide forward and upward without engaging the second fastener post 124, and the spring retainer 166 is for receiving a first end of a spring 168 (e.g., an extension spring or a compression spring). According to some embodiments, second slot 164 also helps prevent first lateral member 130 from being inadvertently lifted out of channel 138 (e.g., by a user picking up the chair with seat member 18), and also serves to provide forward and rearward limits to sliding as desired.

FIG. 6 is an enlarged view of what is shown as area 6-6 in FIG. 5, in accordance with some embodiments. As shown, the lower portion 142 of the first lateral member 130 also includes a sliding bushing 170, the sliding bushing 170 having a rounded contact surface 172 for slidably engaging the sliding surface 100 of the first side mount 42.

As shown in fig. 4, the front and rear cross members 134, 136 are configured to extend between the first and second side members 130, 132 such that the front and rear cross members 134, 136 resist compressive forces between the first and second side members 130, 132.

Fig. 7 is an assembled view of seat frame 16 according to some embodiments. As will be appreciated with reference to fig. 4 and 7, assembly of the seat frame 16 includes assembly of the upper portion 140 to the lower portion 142 of the first lateral member 130 by inserting the tongue 154 into a groove (not shown) and fastening a pin or other fastener through the pivot aperture 160 (fig. 5) in the lower portion 142 and the tongue 154, such that the lower portion 142 is free to angle relative to the upper portion 140 by pivoting with the upper portion 140 at pivot point P1 (fig. 13). Although the upper and lower portions 140, 142 are optionally pivotally coupled, in other embodiments, the upper and lower portions 140, 142 are flexibly coupled (e.g., the corner sections 146 and/or the sections corresponding to the pivot apertures 160 are optionally flexible) in order to facilitate angulation between the upper and lower portions 140, 142. Optionally, the first lateral member 132 is similarly assembled.

In some embodiments, the front and rear cross members 134, 136 are interposed between the first and second side member members. Fig. 8 illustrates the mating feature 158 of the first side member 130 prior to mating with the front cross member 134 according to some embodiments, and fig. 9 is a partial cross-sectional view illustrating the mating feature 158 of the first side member 130 mating with the front cross member 134 after assembly of the front cross member and the first side member 130 according to some embodiments. As shown in fig. 7, when assembled, the seat frame 16 defines an open center 180.

Fig. 10 illustrates a seat member 18 according to some embodiments. As shown, the seat member 18 includes a seat material 200 (such as a resilient material) and a border strip 202 (also described as a perimeter tab), the border strip 202 being stitched or otherwise attached to the perimeter of the seat material 200. In some embodiments, the seat material is an elastic mesh material, such as polyester and polyester copolymers available from Matrex, north carolina. FIG. 11 is a cross-sectional view through the chair at line 11-11 in FIG. 11, according to some embodiments. As shown, the sidebar 202 of the seat member 18 is configured to be received in the sidebar channel 138 of the seat frame 16, thereby securing the seat member 18 to the seat frame 16 under tension to provide a means for supporting the weight of the user.

Having described various features of the chair 10 according to some embodiments, some methods of assembling the chair 10 include assembling the base 12 and the hub 14 as desired with the covers 46, 48 removed. The hembar 202 is secured in the hembar groove 138 in each of the side members 130, 132, and then the wire mesh is tensioned between the materials of the side members 130, 132 by pulling the side members 130, 132 apart (e.g., using a tensioning fixture tensioning approximately 1000 lbs). In some embodiments, a pulling member (not shown), such as a hook, pin, bolt, or other type of fastener, is secured to the lateral members 130, 132 by securing the pulling member in the assembly apertures 204A, 204B, 204C (fig. 5) in the first lateral member 130 and similar apertures in the second lateral member 132. In fig. 5, location 204C is generally indicated, although, according to some embodiments, aperture 204C is hidden behind spring 168. The pulling member is in turn secured to a tensioning system (e.g., a pneumatic or hydraulic system), and the lateral members 130, 132 are tensioned apart.

Once the lateral members 130, 132 are separated as desired, the front and rear cross members 134, 136 are positioned in place between the lateral members 130, 132 like the first and second side mounts 42, 44.

In some embodiments, at least some tensioning of the screen material is released, the binding strips 202 are secured in the binding grooves 138 in each of the front and rear cross members 134, 136, and the cross members 134, 136 are secured between the side members 130, 132. The lateral members 130, 132 are also released onto the side supports 42, 44 so that the first and second side supports 42, 44 and the cross members 134, 136 resist the compressive force applied by the seat material 200 between the first and second lateral members 130, 132. By aligning the side mount pivot aperture 92 with the side member pivot aperture 156, the side mount first slot 162 with the side member first fastener aperture 102, the side mount second fastener aperture 104 with the side member second slot 164, and slidably receiving the side member bushing 170 within the side mount sliding surface 100, the side member is released onto the side mount.

FIG. 12 is a perspective view of the seat frame 16 prior to attachment of the covers 46, 48 to the hub 14 according to some embodiments. In some embodiments, the covers 46, 48 are attached to the side branch seats 42, 44, respectively, such that various features of the lateral members 130, 132 are substantially hidden from view. As shown in fig. 11, the first cover 46 and the first side mount 42 combine to define a U-shaped channel 210, with the first lateral member 130 slidably received in the U-shaped channel 210 and substantially hidden from view. Specifically, as shown in fig. 11, where the first side member is received in channel 210, bottom 220 and sides 222, 224 (including binder strip channel 138) of first side member 130 are substantially hidden from view.

The first cover 46 is fixed to the first side mount 42 by: the fastener post 120 is inserted through the pivot aperture 92 into alignment with the pivot aperture 156 and fastens a fastener (e.g., a bolt) therethrough, the fastener post 122 is inserted through the slot 162 into alignment with the fastener aperture 102 and fastens a fastener (e.g., a bolt) therethrough, and the fastener post 124 is inserted through the slot 164 into alignment with the fastener hole 104 and fastens a fastener (e.g., a bolt) therethrough. After assembly, the upper portion 140 of the side member 130 is pivotally coupled to the rear portion 84 of the side mount 42 at pivot point P2 (fig. 13) and the lower portion 142 is slidingly received in the channel 210 such that a user (not shown) leaning back on the chair causes the upper portion 140 to pivot rearward and the lower portion 142 to slide forward and upward with the bushing 170 riding on the sliding surface 100. According to some embodiments, the second cover 48 is secured to the second side mount 44 in a similar manner.

Fig. 13 and 14 are illustrations of the tilt and lift functions of the chair 10 according to some embodiments, where fig. 13 is the chair 10 in an untilted state and fig. 14 is the chair in a reclined state according to some embodiments. Fig. 13 and 14 show side views of the chair 10 with the first cover 46 removed for ease of understanding. As shown, when the user reclines, the upper portion 140 of the side member 130 pivots relative to the rear portion 84 of the first side mount 42 about the pivot point P2. The upper and lower portions 140, 142 are angled relative to each other, and the lower portion 142 slides upward and rises as the bushing 170 rides upward on the sliding surface 100, providing a means for vertically lifting the lower portion of the lateral member as the upper portion of the lateral member pivots rearward. While some embodiments include a bushing 170 that rests on the lower portion 142, in other embodiments, the sliding surface 100 is formed in the lower portion 142 and the bushing rests on the first side mount 42.

According to some embodiments, where the seat member 18 is assembled on one side of the seat frame 16, the chair 10 provides a more uniform aesthetic when viewed from various locations. As shown, the assembly type allows the chair to avoid the more traditional window frame appearance and provide a full perimeter frame with a substantially continuous seat material 200 between the rear and seat portions of the seat material 200.

The spring 168 secured between the first cover 46 (at the spring tab 126, not shown in fig. 13 and 14, where the cover 46 is removed) and the lower portion 142 (at the spring retainer 166) is an extension spring that assists in returning the chair 10 to the upright position. In other embodiments, a compression spring is used, wherein the spring protrusion 126 and the spring retainer 166 are exchanged between the first cover 46 and the lower portion 142. In still other embodiments, a torsion spring is additionally or alternatively applied, for example, at the first or second pivot points P1, P2, to assist in returning the chair 10 to the upright position.

Various modifications and additions may be made to the specifically discussed embodiments. For example, fig. 15 illustrates a chair 300 substantially similar to chair 10, according to some embodiments. However, the chair 300 is shown without armrests and without a base of casters (rather than a base with casters).

As another example, fig. 16 shows another means for vertically lifting the lower portion of the lateral member when the upper portion of the lateral member is pivoted rearward. Specifically, fig. 16 shows a post 400 of a retaining bushing 402 and an angled slot 404 formed in a lateral member 406 (e.g., similar to the first lateral member 130). The stem 400 is coupled to a first side mount 410 (e.g., similar to the first side mount 42). As the lateral member 406 moves upward, the angled slot 404 rides on the bushing 402, thereby moving the lateral member 406 upward.

As still further examples, fig. 17-19 illustrate chair embodiments having various seat member configurations. Fig. 17 illustrates a chair 500 having a seat member that includes a mesh upper portion 502 (e.g., secured between upper portions of corresponding lateral members) and a solid lower portion 504 (e.g., integrally formed with lower portions of the lateral members), according to some embodiments. Fig. 18 illustrates a chair 600 having a seat member that includes a wire mesh lower portion 604 (e.g., secured between lower portions of corresponding lateral members) and a solid upper portion 602 (e.g., integrally formed with upper portions of the lateral members), according to some embodiments. Fig. 19 illustrates a chair 700 having a seat member that includes a solid upper portion 702 (e.g., integrally formed with an upper portion of a corresponding lateral member) and a solid lower portion 704 (e.g., integrally formed with a lower portion of a lateral member), wherein the upper portion 702 and the lower portion 704 have a gap 706 therebetween for pivoting/tilting between the upper portion 702 and the lower portion 704, according to some embodiments. In other embodiments, the gap 706 is replaced and/or augmented with a flexible material to facilitate relative movement between the upper portion 702 and the lower portion 704.

As previously referenced, various modifications and additions may be made to the discussed embodiments without departing from the scope of the present invention. Furthermore, although the embodiments have been described above with reference to specific features, the scope of the present invention also includes embodiments having different combinations of features and embodiments that do not include all of the features described above.

Claims (31)

1. A chair, the chair comprising:

a base configured to support the chair on a surface;

a hub supported by the base and comprising:

a first side mount positioned at a first side of the chair, the first side mount including a rear portion and a bottom portion;

a first cover coupled to the first side mount to define a first groove with the first side mount;

a second side mount positioned on a second side of the chair, the second side mount including a rear portion and a bottom portion; and

a second cover coupled to the second side mount to define a second groove with the second side mount; and

a seat frame, the seat frame comprising:

a first lateral member including a lower portion and an upper portion pivotally coupled to the rear portion of the first side mount and configured to be angled relative to the lower portion, the lower portion of the first lateral member being slidably received in the first channel such that both sides and a bottom of the lower portion received within the first channel are substantially hidden from view; and

a second lateral member including a lower portion and an upper portion pivotally coupled to the rear portion of the second side mount and configured to be angled relative to the lower portion, the lower portion of the second lateral member being slidably received in the second channel such that both sides and a bottom of the lower portion received within the second channel are substantially hidden from view.

2. The chair of claim 1, wherein the upper portion and the lower portion of the first lateral member are pivotally coupled.

3. The chair of claim 2, wherein the upper portion and the lower portion of the first lateral member are pivotally coupled at a location that generally corresponds to a location below a hip joint of a user.

4. The chair of claim 1, wherein the upper portion and the lower portion of the first lateral member are flexibly coupled.

5. The chair of claim 1, wherein the first side mount defines a substantially L-shaped side profile.

6. The chair of claim 1, wherein the rear portion and the bottom portion of the first side mount define an acute angle with respect to each other in a side profile.

7. The chair of claim 1, wherein a bottom of the first groove defines a sliding surface and the lower portion of the first lateral member has a bushing that seats over the sliding surface to be slidably received against the sliding surface.

8. The chair of claim 7, wherein the sliding surface is configured such that when the upper portion of the first lateral member pivots rearward relative to the rear portion of the first side mount, the lower portion of the first lateral member slides forward and is lifted vertically on the sliding surface.

9. The chair of claim 1, wherein the seat frame further comprises: a front cross member coupling the lower portion of the first side member and the lower portion of the second side member together; and a rear cross member coupling the upper portion of the first side member and the upper portion of the second side member together, the rear cross member, the front cross member, the first side member, and the second side member combining to define an open center.

10. The chair of claim 9, further comprising an elastic mesh coupled directly to the first and second lateral members, the elastic mesh held under tension between the first and second lateral members to support the weight of a user.

11. The chair of claim 10, wherein the first side member, the second side member, the front cross member, and the rear cross member are configured to resist a compressive force exerted by the wire mesh on the seat frame.

12. The chair of claim 1, further comprising a resilient seat member secured under tension between the first and second lateral members, the first and second side mounts supporting the first and second lateral members against a compressive force exerted by the resilient seat member on the first and second lateral members.

13. The chair of claim 1, further comprising a seat member integrally formed with the upper portion of the first lateral member and the upper portion of the second lateral member.

14. The chair of claim 1, further comprising a seat member integrally formed with the lower portion of the first lateral member and the lower portion of the second lateral member.

15. The chair of claim 1, wherein the upper portion and the lower portion of the first lateral member and the upper portion and the lower portion of the second lateral member are both substantially inflexible, molded polymer components.

16. The chair of claim 1, further comprising a spring secured between a lower portion of the first lateral member and the first side mount.

17. The chair of claim 1, further comprising a torsion spring secured between the upper portion of the first lateral member and the first side mount.

18. The chair of claim 1, further comprising a torsion spring secured between the upper portion and the lower portion of the first lateral member.

19. A chair, the chair comprising:

a base configured to support the chair on a surface;

a hub supported by the base and comprising:

a first side mount positioned at a first side of the chair and having a rear portion extending substantially vertically and a bottom portion extending substantially horizontally and defining a first channel;

a second side mount positioned at a second side of the chair and having a rear portion extending substantially vertically and a bottom portion extending substantially horizontally and defining a second channel; and

a seat frame, the seat frame comprising:

a first lateral member including a lower portion and an upper portion connected to the lower portion such that the lower portion and the upper portion are configured to be angled relative to each other, the upper portion of the first lateral member pivotally coupled to the first side mount at a fixed pivot, the lower portion of the first lateral member slidably received in the first groove, the first groove defining a sliding surface, and the lower portion of the first lateral member having a bushing slidably received against the sliding surface such that the lower portion of the first lateral member is vertically lifted as the upper portion of the first lateral member pivots rearward relative to the first side mount about the fixed pivot; and

a second lateral member including a lower portion and an upper portion coupled to the lower portion such that the lower portion and the upper portion are configured to be angled with respect to each other, the lower portion of the second lateral member being slidably received in the second channel.

20. A chair, the chair comprising:

a base configured to support the chair on a surface;

a hub supported by the base and comprising:

a first side mount positioned at a first side of the chair and having a rear portion extending substantially vertically and a bottom portion extending substantially horizontally and defining a first channel;

a second side mount positioned at a second side of the chair and having a rear portion extending substantially vertically and a bottom portion extending substantially horizontally and defining a second channel; and

a seat frame, the seat frame comprising:

a first lateral member including a lower portion and an upper portion connected to the lower portion such that the lower portion and the upper portion are configured to be angled with respect to each other, the lower portion of the first lateral member being slidably received in the first channel; and

a second lateral member including a lower portion and an upper portion coupled to the lower portion such that the lower portion and the upper portion are configured to be angled with respect to each other, the lower portion of the second lateral member being slidably received in the second channel;

means for vertically lifting the lower portion of the first lateral member and the lower portion of the second lateral member as the upper portion of the first lateral member pivots rearward about a fixed pivot location relative to the rear portion of the first side mount; and

means for supporting a user's weight between the first and second lateral members.

21. The chair of claim 20, wherein the means for lifting comprises a sliding surface and a bushing slidably received against the sliding surface.

22. The chair of claim 21, wherein the bushing is coupled to the lower portion of the first lateral member.

23. The chair of claim 20, wherein the means for raising includes a slot formed in the lower portion of the first lateral member and a rider connected to the bottom portion of the first side mount, the rider being slidably received in the slot.

24. The chair of claim 20, wherein the means for supporting comprises a wire mesh extending between the first and second lateral members.

25. The chair of claim 20, wherein the means for supporting comprises a seat secured between the first and second lateral members and a backrest secured between the first and second lateral members.

26. A method of manufacturing a chair, the method comprising:

tensioning a seat material between a first lateral member having an upper portion and a lower portion and a second lateral member having an upper portion and a lower portion;

securing a rear cross member between the upper portion of the first side member and the upper portion of the second side member;

securing a front cross member between the lower portion of the first side member and the lower portion of the second side member; and

releasing the first and second side members onto first and second side mounts of a hub of a chair such that the first and second side mounts resist compression between the first and second side members; and is

Securing a first cover to the first side mount and a second cover to the second side mount to cover the second lateral member such that the first lateral member is slidably received between the first cover and the first side mount and the lower portion of the second lateral member is slidably received between the second cover and the second side mount.

27. The method of claim 26, further comprising pivotally coupling the upper portion of the first lateral member relative to a rear portion of the first side mount.

28. The method of claim 26, wherein tensioning the seat material between the first and second lateral members comprises securing the seat material within first and second welt grooves formed in the upper and lower portions of the first and second lateral members.

29. The method of claim 28, wherein the first and second border strip grooves are formed on outwardly facing sides of the first and second lateral members.

30. The method of claim 28, wherein the first and second covers are secured to the first and second side supports such that the first and second welt grooves are substantially hidden from view.

31. The method of claim 26, further comprising slidably receiving the lower portion of the first lateral member between the first cover and the first side mount by placing a bushing coupled to the lower portion of the first lateral member in sliding contact with a sliding surface of the first side mount.