Seat back for office chair

Abstract

A seatback for an office chair is efficiently manufactured and assembled. The seatback includes a tensioner for tensioning the flexible support on the structural frame. A tensioner is connected between the lower edge of the flexible support and the upright member of the frame such that the tensioner stretches the flexible support between the upper and lower edges of the flexible support and maintains the flexible support in a tensioned state on the structural frame. An armrest support may be integrally formed with each of the upright members of the structural frame, and an armrest housing may be vertically adjustably mounted to each of the armrest supports. The activation mechanism is positioned adjacent to the lower end of the armrest housing and is connected to the lock element such that movement of the activation mechanism toward the upper end of the housing causes the lock element to move to the unlocked position.

Description

Technical Field

[0001] The present invention relates to office chairs, and more particularly, to a seat back for an office chair. Background Art

[0002] In a competitive office chair market, users require office chair options that provide comfort, functionality, and height adjustability, but these chairs must also be cost-effective to purchase and manufacture. Thus, office chair manufacturers are constantly seeking improved methods of manufacturing office chairs and office chair components.

[0003] Some office chair manufacturers improve manufacturing efficiency by reducing or simplifying components such as backrest supports or mechanisms. For example, some modern office chairs have moved to a one-piece seat back, which is typically molded integrally to form a plastic shell, thus reducing the number of seat back components from multiple elements that need to be assembled to a single element that can simply be attached to the office chair base. Other office chairs have reduced the size of the seat mechanism (typically a series of controls and springs) and the number of spring elements within the mechanism in order to simplify the assembly process and reduce weight. Still other office chairs eliminate features such as certain seat adjusters or features such as lumbar supports or armrests.

[0004] However, each of the above efficacy efforts has drawbacks, including aesthetic challenges, reduced comfort, and adjustment features. Thus, manufacturers continue to seek efficacy that can minimize these and other drawbacks. Summary of the Invention

[0005] The present invention provides a seat back for an office chair that can be effectively manufactured and assembled. In one embodiment, the seat back includes: a structural frame having a pair of spaced-apart upright members each having an upper end and a lower end, a lower transverse member connecting the lower ends of the uprights, and an upper transverse member connecting the upper ends of the uprights; and a flexible support member including a user support surface having an upper edge, a lower edge, and a pair of side edges, the upper edge of the flexible support member being mounted on the upper transverse member of the frame.

[0006] The seat backrest may include a tensioner for tensioning a flexible support member on a structural frame. In one embodiment, the tensioner is connected between the lower edge of the flexible support member and an upright member of the frame such that the tensioner stretches the flexible support member between the upper and lower edges thereof and maintains the flexible support member in a tensioned state on the structural frame. Each of the upright members may include a tensioner support, and the tensioner may be connected between the lower edge of the flexible support member and the tensioner support. The tensioner may include a base and a pair of arms extending from the base, the base extending along the lower edge of the flexible support member and the arms each extending along one of the side edges of the flexible support member. Each of the tensioner arms may be connected to an associated one of the tensioner supports such that the tensioner may engage the tensioner support and pivot to stretch the flexible support member on the structural frame.

[0007] In another embodiment, the seat backrest includes an armrest support integrally formed with each of the upright members of the structural frame and an armrest housing vertically adjustably mounted to each of the armrest supports. A locking mechanism within the housing may include a locking element movable between a locked position in which the housing is secured in place on the armrest support and an unlocked position in which the housing is vertically adjustable along the armrest support. An activation mechanism is positioned adjacent to the lower end of the armrest housing and connected to the locking element such that movement of the activation mechanism toward the upper end of the housing causes the locking element to move to the unlocked position. In one embodiment, the armrest support includes a pair of guide rails, and one of the guide rails may define a plurality of vertically spaced notches in which the locking element is positioned when in the locked position.

[0008] The present invention also includes a method for constructing a seat backrest. The method includes the steps of: providing a flexible support member including a user support surface having an upper edge, a lower edge, and a pair of side edges; providing a structural frame having a pair of spaced-apart upright members each having an upper end and a lower end, a lower transverse member connecting the lower ends of the uprights, and an upper transverse member connecting the upper ends of the uprights; providing tensioner arms having first and second ends; attaching the first ends of the tensioner arms to the lower edge of the flexible support member; mounting the upper edge of the flexible support member to the upper transverse member of the structural frame; engaging the second ends of the tensioner arms with one of the upright members of the structural frame; and pivoting the tensioner arms about the second ends thereof to pull the first ends of the tensioner arms toward the structural frame when the tensioner arms are used to stretch the flexible support member between the upper and lower edges thereof.

[0009] In one embodiment, the method may further include: integrally forming the armrest support with the upright member of the structural frame; and providing a pair of armrest shells, each shell being associated with one of the armrest supports. The armrest shells may be slidably attached to the armrest supports and may be selectively vertically adjustable along the armrest supports. Operation of the armrest may include vertically pressing a button panel on the armrest shell to activate an activation mechanism for locking and unlocking the adjustability of the armrest. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a perspective view of a seat back according to an embodiment of the present invention.

[0011] Figure 2 is an exploded rear view of the tensioner and the flexible support.

[0012] Figure 3 is a rear view of the tensioner and the flexible support.

[0013] Figure 4 is a side view of the tensioner and the flexible support partially attached to the support frame.

[0014] Figure 5 is a bottom view thereof.

[0015] Figure 6 is a close-up view of the tensioner support.

[0016] Figure 7 is a front perspective view of the tensioner and the flexible support partially attached to the support frame.

[0017] Figure 8 is a front perspective view of the flexible support attached to the support frame.

[0018] Figure 9 is a rear perspective view thereof.

[0019] Figure 10 is a side view of a seat back without an attached armrest according to an embodiment.

[0020] Figure 11 is a side view of a seat back according to an embodiment.

[0021] Figure 12 is an exploded view of an armrest according to an embodiment.

[0022] Figure 13 is a right side view thereof.

[0023] Figure 14 is a front view thereof.

[0024] Figure 15 is a top view thereof.

[0025] Figure 16 A side cross-sectional view of a part of an armrest.

[0026] Figure 17 A front cross-sectional view thereof.

[0027] Figure 18 A cross-sectional side view of a seat back with an armrest.

[0028] Figure 19 A side cross-sectional view of an armrest showing the activation mechanism in the locked position.

[0029] Figure 20 A side cross-sectional view of an armrest showing the activation mechanism in the unlocked position. Detailed Description

[0030] A seat back for an office chair according to an embodiment of the present invention is shown in Figure 1 and is generally designated 10. The seat back 10 generally includes a structural frame 12, a flexible support material 14 supported on the frame 12, and a pair of armrests 16 mounted directly on the structural frame 12. Although not shown, the seat back 10 is designed to be supported above the ground surface by a conventional office chair base, which may include a height-adjustable pedestal supported on a plurality of legs, the legs optionally including casters.

[0031] The structural frame 12 and a system for mounting the flexible support material 14 in a tensioned state on the structural frame using a tensioner 18 are shown in Figures 1 - 9In the middle. The frame 12 is generally a rigid structure that supports the frame 12 for attachment to the seat base and supports the back of a user placed on the seat, and the seat is also supported on the seat base adjacent to the seat back 10 in a conventional manner. The frame 12 can be molded from rigid plastic or can be constructed from another structural material. In one embodiment, the frame 12 is a perimeter frame that includes a pair of spaced-apart uprights 20 having a lower end 22 and an upper end 24. The uprights 20 can be connected at their upper ends 24 by an upper transverse member 26 and can be connected at their lower ends 22 by a lower transverse member 28. The frame 12 can have a front surface 32 facing the user's direction, a rear surface 34 opposite the front surface, an outer surface 35, and an inner surface 37. As shown, the frame members together define a central opening 30. In one embodiment, the frame 12 includes an attachment portion 36 extending from the front surface 32 of the lower transverse member 26. Although a variety of attachment mechanisms can be used to connect the seat back 10 to the seat base, the illustrated embodiment shows the attachment portion 36, which includes a notch 38 for receiving a portion of the seat base and a series of attachment holes 40 for securing the seat back 10 to the seat base. The frame 12 can additionally include a tensioner support 41 for engaging the tensioner 18, as discussed in more detail below, to allow the use of the tensioner 18 to stretch the flexible support member onto the frame 12. In Figure 6 In one embodiment shown, the frame 12 includes a series of support ribs 43 on the rear surface 34, and the tensioner support 41 includes a pair of windows 45 formed in the support ribs 43, with one window 45 within the support ribs 43 on the first upright of the uprights 20 and the other window within the support ribs 43 on the other upright of the uprights 20. The windows 45 can each be positioned at the same height on the uprights 20, between the upper end 24 and the lower end 22 of the uprights 20. In one embodiment, the windows 45 are positioned near the midpoint between the upper end 24 and the lower end 22 of the uprights. In another embodiment, the windows 45 can be positioned at different heights on the uprights 20.

[0032] The flexible support member 14 is attached to the structural frame 12 to extend above the central opening 30 and form a comfortable back support surface for the user. In one embodiment, the flexible support member 14 is formed from a flexible thermoplastic elastomer, and in a more specific embodiment, from a thermoplastic polyester elastomer known as and manufactured by DuPont TM Other flexible materials can also be used, including knitted or woven fabrics and elastomeric fabrics. The flexible support member 14 can be manufactured by a variety of methods and, in one embodiment, is injection molded as a single integral part. Refer to Figure 1 and Figure 2, the flexible support member 14 includes a central section 40 having a front surface 42 facing the user and an opposite rear surface 44. As shown, the central section 40 includes a series of perforations 46 that can add aesthetic value and comfort to the flexible support member 14. The flexible support member 14 also includes an upper edge 48, a pair of lateral side edges 50, and a bottom edge 52. The edges 48, 50, 52 may be formed to have a greater thickness than the central section 40 to provide enhanced strength to the perimeter of the flexible support member 14. In one embodiment, the upper edge 48 is formed to include a recess 54 extending from the rear surface 44 of the flexible support member 14.

[0033] In one embodiment, the flexible support member 14 is mounted to the structural frame in a tensioned state by a tensioner 18, which enables the effective assembly of the flexible support member 14 in a tensioned state on the frame 12 with a minimum of individual fasteners and tools. As described in more detail below, the tensioner 18 is attached to the flexible support member 14 and mounts the flexible support member 14 to the frame 12 by inserting a portion of the upper transverse member 26 of the frame 12 into the recess 54 in the flexible support member 14; engaging the tensioner 18 with the frame 12 in a first position, as Figures 4 - 7 shown; and then pivoting the tensioner 18 to a second mounting position on the frame 12, as Figures 8 - 9 shown, where the tensioner 18 is used to stretch the flexible support member 14 as the tensioner 18 pivots from the first position to the mounting position. As Figure 2 shown, the tensioner 18 of the illustrated embodiment is formed of a generally rigid material, such as the same polymer as the frame 12, or a different structural polymer or other material. In one embodiment, the tensioner 18 is a U-shaped member having a base 60 with a first end 62 and a second end 64, and a pair of arms 66 extending from the base 60 at opposite ends 62, 64. The arms 66 may extend parallel or substantially parallel to each other and each have a base end 68 at the base 60 and a pivot end 70 remote from the base 60. In the illustrated embodiment, the tensioner base 60 defines a length between the first end 62 and the second end 64 that is approximately the same as the length of the bottom edge 52 of the flexible support member 14. The tensioner 18 is attached to the rear surface 44 of the flexible support member 14 and, in the illustrated embodiment, the tensioner 18 is attached to the rear surface 44 of the bottom edge 52 of the flexible support member 14 by conventional attachment methods, such as a series of lugs, fasteners, heat stakes, ultrasonic welding, overmolding, or other locking features. The entire tensioner 18 may be attached to the flexible support member 14, although in one embodiment, the tensioner arms 66 are not attached to the flexible support member 14 such that the tensioner arms 66 are free to pivot away from the flexible support member 14.

[0034] The tensioner arms 66 each include a structure that enables the arms 66 to pivotally engage with the tensioner supports 41 on the uprights 20. As described above, in the illustrated embodiment, the tensioner supports 41 are windows 45 formed in the support ribs 43 of the uprights 20. In one embodiment, the tensioner arms 66 may each include a hook 72 extending from the pivoting end 70 of the tensioner arm 66. As Figure 6 shown, the hooks 72 face the rear surface 34 of the frame 12, and when the flexible support 14 is attached to the frame 12, each hook 72 is capable of mating with one of the windows 45. It is noted that the length of the tensioner arms 66 is predetermined to provide a desired amount of tension to the flexible support 14 when the hooks 72 are hooked to the tensioner supports 41 and the arms 66 are positioned against the rear surface 34 of the frame 12 in the installed position. For example, the length of the tensioner arms 66 is such that when the flexible support 14 is attached to the tensioner 18 and the tensioner is in its installed position on the frame 12, the distance between the upper edge 48 and the lower edge 52 of the flexible support 14 is stretched, as Figure 8 shown. In other words, when the flexible support 14 is in the Figures 4 - 7 first position shown, the flexible support 14 may have a first unstretched length between the upper edge 48 and the lower edge 52; and when the tensioner 18 is attached to the flexible support 14 and the tensioner 18 is attached to the frame 12 in the installed position, where the tensioner arm abuts the rear surface 34 of the frame 12, the flexible support 14 has a second stretched length that is greater than the first length.

[0035] In one embodiment, the tensioner arms 66 further include a structure for securing the tensioner 18 to the frame 12 when the tensioner 18 is in the installed position. Referring to Figures 2 - 7 , the tensioner 18 includes a screw boss 80 on each of the tensioner arms 66. As shown, the screw boss 80 is positioned near the midpoint along the arm 66, but the position on the arm 66 can be changed as desired. Referring to Figure 8 , the frame 12 defines tensioner holes 82 in each of the uprights 20. When the tensioner 18 is in the installed position, the tensioner holes 82 are each aligned with one of the screw bosses 80 such that a conventional fastener (not shown) can be inserted through each upright 20 and the tensioner 18 to hold the tensioner 18 in the installed position. In an alternative embodiment, the tensioner 18 and the frame 12 may be provided with features that enable the tensioner 18 to snap-fit with the frame 12 when the tensioner 18 is moved to the installed position.

[0036] The process of attaching the flexible support 14 to the structural frame 12 is shown in Figures 2 - 9 . Figure 2Shows the state of the flexible support 14 before it is attached to the tensioner 18 or the frame 12, where the tensioner 18 is shown in an exploded view. In this embodiment, the flexible support 14 and the tensioner 18 have been formed separately, each formed as a single part. The flexible support 14 is formed by molding a flexible material such as a thermoplastic elastomer into a desired shape, and the tensioner 18 is formed by molding a rigid plastic into a U-shaped form, but the flexible material can also be a knitted or woven fabric having elastomeric or other elastic properties. Figure 3 Shows the tensioner 18 attached to the flexible support 14 along the bottom edge 52 of the flexible support 14, where the tensioner base 60 extends along the bottom edge 52 from the side edge 50 to the side edge 50 of the flexible support 14. As described, the tensioner base 60 can be attached to the bottom edge 52 by conventional methods. In the case where the base 60 is attached to the bottom edge 52, the tensioner arms 66 each extend upward along one of the side edges 50, and the hooks 72 extend rearward from the tensioner arms 66 away from the flexible support 14.

[0037] Then, the assembled flexible support 14 and tensioner 18 are attached to the structural frame 12. In one embodiment, this begins by inserting a portion of the upper transverse member 26 of the frame 12 into the recess 54 of the flexible support 14, as Figures 4 - 7 shown. Then, the hooks 72 of the tensioner 18 are inserted into the tensioner support windows 45 on the frame 12, where the tensioner arms 66 extend at an angle away from the uprights 20, also as Figure 6 shown. From this position, the tensioner arms 66 pivot about the hooks 72, thereby moving the base 60 of the tensioner 18 along an arcuate path until the tensioner 18 abuts the rear surface 34 of the frame 12, resulting in the tensioner 18 being in the Figure 8 mounting position shown. It is noted that when the tensioner 18 pivots to the mounting position, the flexible support 14 is stretched by the tensioner 18 from an unstretched state to a stretched and tensioned state. The stretching may occur mainly in the vertical direction (i.e., the upper edge 48 and the bottom edge 52 are stretched away from each other), but may also occur in the transverse direction from side edge 50 to side edge 50, depending on the respective orientation of the tensioner arms 66 relative to the tensioner base 60. In one embodiment, when causing the flexible support 14 to stretch around the curved front surface 32, the concave curvature of the front surface 32 of the structural frame 12 enhances the stretching of the flexible support 14. In the Figure 8 mounting position shown, the screw bosses 80 on the tensioner 18 are aligned with the tensioner holes 82 in the frame 12, and fasteners are driven through the holes 82 and into the screw bosses 80 to hold the tensioner 18 and the flexible support 14 in place.

[0038] Refer to Figures 10 - 20, the seat back 10 may additionally include an armrest system 100 attached to or integrally formed with the seat back 10. In one embodiment, the armrest system 100 includes an armrest support 102 integrally formed with the structural frame 12, and an armrest housing 104 adjustably attached to the armrest support 102. The armrest housing 104 includes an upper end 106 and a lower end 108. The upper end 106 supports an armrest pad 110, and the lower end 108 includes an actuating mechanism 112 for selectively locking and unlocking the adjustability of the armrest housing 104 on the armrest support 102.

[0039] Reference Figure 5 , Figure 8 and Figure 9 , for example, the armrest system 100 includes armrest supports 102 formed on the outer surface 35 of each of the uprights 20 of the structural frame 12. These armrest supports 102 may be mirror images of each other, one on the right side of the frame 12 and the other on the left side. In one embodiment, the armrest supports 102 are integrally molded with the structural frame 12 as a single piece for efficient manufacturing. Each armrest support 102 includes a first guide rail member 114 and a second guide rail member 116 spaced apart from the first guide rail member 114. As illustrated, the guide rail members 114, 116 extend parallel to each other in the vertical direction along the outer surface 35 of each upright 20. The first guide rail member 114 includes a base portion 118 and a flange member 120. The base portion 118 extends from the upright 20 and has an inner wall 122 and an outer wall 124. The inner wall 122 faces the second guide rail member 116, and the outer wall 124 is opposite the inner wall 120. In one embodiment, the flange member 120 extends from the outer wall 124 at the distal end of the base portion 118. The second guide rail member 116 includes a base portion 128, a flange member 130, and a rack 132. The base portion 128 extends from the upright 120 and includes an inner wall 134 and an outer wall 136. The inner wall 134 faces the inner wall 122 of the first guide rail member 114. The flange member 130 extends from the outer wall 136 at the distal end of the base portion 128. The rack 132 extends from the inner wall 134 toward the first guide rail member 114 and includes a series of vertically spaced notches 140.

[0040] Reference Figure 12, the armrest housings 104 are each adjustably mounted to one of the armrest supports 102. Like the armrest supports 102, the armrest housings 104 can be mirror images of each other, one on the left side of the frame 12 and the other on the right side. As described, each armrest housing 104 includes an upper end 106 and a lower end 108, and the upper end 106 supports the armrest pad 110. In one embodiment, the housing 104 includes an elongate sidewall 150 having a C-shaped cross-section. The upper end 106 includes a pad support 142 that extends at an angle from the sidewall 150 and includes a pair of upwardly extending spaced-apart walls 144. A cover 146 is assembled above the upper end 106, between the walls 144, and is attached to the armrest housing 104 via attachment press-fit pins 148 that extend through portions of the walls 144 and the cover 146. In one embodiment, the cover 146 defines a slot 151 that extends in the front-to-back direction on the cover 146. The armrest pad 110 is horizontally adjustably attached to the cover 146 via a pair of connectors 152 that extend through the pad 110 and the slot 151. More specifically, the pad 110 includes a plate 154 and a cushion 156. The connectors 152 extend through the plate 154 to attach the plate 154 to the cover 146, and the cushion 156 is attached to the plate 154 to form an exposed surface for a user's arm to rest on.

[0041] The C-shaped sidewall 150 defines an elongate opening 160 that extends generally from the upper end 106 to the lower end 108, and a support insertion opening 162 at the lower end 108. In assembly, the elongate opening 160 faces the armrest support 102, and the armrest housing 104 is attached to the armrest support 102 by inserting a first guide member 114 and a second guide member 116 into the support insertion opening 162 and sliding the armrest housing 104 along the first guide member 114 and the second guide member 116, wherein a first edge 170 of the elongate opening 160 engages the first guide member 114 and a second edge 172 engages the second guide member 116 to hold the armrest housing 104 on the guides 114, 116.

[0042] The activation mechanism 200 is inside the armrest housing 104 and is used to selectively lock and unlock the armrest housing 104 along the armrest support 102 at a desired vertical position. The activation mechanism 200 generally includes an armrest lining 202, an activation plate 204, a retainer plate 206, and a locking pin 208. The armrest lining 202 is positioned within the armrest housing 104 and includes a front surface 212 and lateral sides 214. The armrest lining 202 is positioned against the armrest housing sidewall 150, with the front surface 212 facing away from the sidewall 150. In one embodiment, each lateral side 214 includes a pair of leaf springs 221 formed together with the armrest lining 202. When the armrest housing 104 is positioned on the armrest support 102, the leaf springs 221 respectively engage the first guide rail 114 and the second guide rail 116 elastically to eliminate any tolerances between the armrest housing 104 and the armrest support 102 and provide a snug fit of the armrest housing 104 on the armrest support 102.

[0043] The activation plate 204 is slidable vertically within the housing 104 to drive the locking pin 208 between a locked position and an unlocked position. In one embodiment, the activation plate 204 is an elongate plate that is positioned within the housing 104 against the front surface 212 of the armrest lining 202. The activation plate 204 includes a sidewall 219 having an upper end 220 and a lower end 222 and defines a longitudinal length between the upper end 220 and the lower end 222. An angled slot 226 is defined in the sidewall 219, where the angled slot 226 extends at an angle of approximately 45 degrees relative to the longitudinal length. The angled slot 226 includes an upper end 227 and a lower end 229. In one embodiment, the activation plate 204 also defines a pair of vertical slots 228. When positioned within the armrest housing 104, the upper end 220 of the activation plate 204 is positioned near the upper end 106 of the housing 104, and the lower end 222 of the activation plate 204 is positioned near the lower end 108 of the housing 104 adjacent to the support insertion opening 162. An activation spring 230 is positioned within the armrest housing 104 between the upper end 106 of the housing 104 and the upper end 220 of the activation plate 204. A button plate 205 is attached to the lower end 222 of the activation plate 204 within the support insertion opening 162.

[0044] The retainer plate 206 is positioned above the activation plate 204 such that the activation plate 204 is clamped between the armrest lining 202 and the retainer plate 206. In one embodiment, the retainer plate 206 is fixedly positioned within the armrest housing 104 such that the activation plate 204 slides relative to the retainer plate 206. As shown, the retainer plate 206 includes a sidewall 240 having an upper end 242 and a lower end 244. The sidewall 240 defines a horizontal slot 246 that generally aligns with the angled slot 226 of the activation plate 204. The sidewall 204 also defines a pair of mounting holes 248 that align with screw bosses 250 on the housing 104 to effect a fixed attachment of the retainer plate 206 to the housing 104 by means of fasteners 252 that extend through the mounting holes 248 in the retainer plate 206, the vertical slots 228 in the activation plate 204, the armrest lining 202 and into the screw bosses 250. A pair of angled tines 260 extend from the lower end 244 of the retainer plate 206. The angled tines 260 enable the armrest housing 104 to be slidably inserted onto the armrest support 102 and, once fully inserted, engage the guide members 114, 116 of the armrest support 102 to retain the housing 104 on the armrest support 102.

[0045] When assembling the activation mechanism 200, the locking pin 208 extends through the angled slot 226 in the activation plate 204 and the horizontal slot 246 in the retainer plate 206. The locking pin 208 can be a bolt or other pin-like member. Referring Figure 19 and Figure 20 , the activation mechanism 200 is arranged to move the locking pin 208 between the locked position shown in Figure 19 and the unlocked position shown in Figure 20 . In the locked position, the button plate 205 is released and the button plate 205 extends downwardly beyond the lower end 108 of the armrest housing 104. The activation plate 204 is in the lowered position and is biased in this position by the activation spring 230. The locking pin 208 is driven to the upper end 227 of the angled slot 226 and moves in this position to engage a selected notch in the notch 140 in the armrest support 102. In the unlocked position, the button plate 205 is pressed upwardly along the longitudinal length of the activation plate 204 and the activation plate 204 slides vertically upwardly, thereby compressing the spring 230. The path of the horizontal slot 246 in the retainer plate and the angled slot 226 in the activation plate 204 causes the locking pin 208 to move to the lower end 229 of the angled slot 226 and thus disengage from any notch 140 to enable the armrest housing 104 to freely slide relative to the armrest support 102 to a desired vertical position.

[0046] The assembly of the armrest system 100 includes positioning an armrest housing 104 vertically above an armrest support 102. Note that the appropriate right or left armrest housing 104 will be positioned above the associated right or left upright 20 of the structural frame 12. Refer to Figure 10 , the left armrest housing 104 is positioned above the armrest support 102 on the left upright 20, wherein the support insertion opening 162 of the armrest housing 104 is positioned above the guide rails 114, 116 of the armrest support 102, and the elongated opening 160 faces the upright 20. Then, the armrest housing 104 is slid onto the armrest support 102 by inserting the guide rails 114, 116 into the armrest insertion opening 162 and sliding the armrest housing 104 downward onto the armrest support 102. The angled prongs 260 on the retainer plate 206 flex when inserted between the guide rails 114, 116, and the retainer plate 206 slides between the guide rails 114, 116 until the prongs 260 slide past the guide rails 114, 116 and release. The button plate 205 can be attached to the activation plate 204 before or after the housing 104 has been slid onto the guide rails 114, 116. The leaf spring 221 of the armrest sleeve 202 engages the guide rails 114, 116 to elastically eliminate any slack between the armrest housing 104 and the armrest support 102. With the armrest housing 104 positioned on the armrest support 102, the armrest system 100 enables adjustment of the height of the armrest housing 104 (and thus the armrest pad 110) by user activation or release of the activation mechanism 200. As described above, when the button plate 205 of the activation mechanism 200 is released (i.e., not pressed by the user), the locking pin 208 is driven to the upper end 227 of the angled slot 226 and will extend into the nearest notch 140 as the armrest housing 104 is adjusted past the notch 140. As long as the button plate 205 is not pressed, the pin 208 will engage in the notch 140 and will prevent the armrest housing 104 from moving vertically. When the user presses the button plate 205 in the upward direction, the activation plate 204 slides vertically along the retainer plate 206, and the pin 208 is driven to the lower end 229 of the angled slot 226, disengaging the pin 208 from the notch 140 and allowing the armrest housing 104 to move vertically along the armrest support 102 until the button plate 205 is released and the pin 208 slides back to the upper end of the angled slot 226 and into one of the notches 140.

[0047] Directional terms such as "vertical", "horizontal", "top", "bottom", "upper", "lower", "inner", "inward", "outer", and "outward" are used to assist in describing the present invention based on the orientation of the embodiments shown in the figures. The use of directional terms should not be construed as limiting the present invention to any particular orientation.

[0048] The foregoing description is of the presently contemplated embodiments of the present invention. Various changes and modifications may be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. The disclosure is presented for illustrative purposes only and should not be construed as an exhaustive description of all embodiments of the invention or as limiting the scope of the claims to the specific elements illustrated or described in connection with these embodiments. By way of example and not limitation, any individual element of the described invention may be replaced by an alternative element that provides substantially similar functionality or otherwise provides suitable operation. This includes, for example, alternative elements that are currently known, such as those that may be currently known to those of ordinary skill in the art, and alternative elements that may be developed in the future, such as those that may be recognized as alternatives by those of ordinary skill in the art at the time of development. Additionally, the disclosed embodiments include a plurality of features that are described in concert and may cooperate to provide a series of benefits. The invention is not limited to those embodiments that include all of these features or provide all of the recited benefits, unless expressly set forth otherwise in the published claims. Any reference to a claim element in the singular (e.g., using the articles "a," "an," "the," or "said") is not to be construed as limiting the element to the singular.

Claims

1. A seat back for an office chair, comprising: A structural frame having a pair of spaced-apart upright members each having an upper end and a lower end, a lower transverse member connecting the lower ends of the upright members, and an upper transverse member connecting the upper ends of the upright members; A flexible support member including a user support surface having an upper edge, a lower edge, and a pair of side edges, the upper edge of the flexible support member being mounted on the upper transverse member of the frame; And A tensioner connected between the lower edge of the flexible support member and the upright member of the frame such that the tensioner stretches the flexible support member between the upper and lower edges thereof and maintains the flexible support member in a tensioned state on the structural frame.

2. The seat backrest according to claim 1, wherein, Each of the upright members includes a tensioner support located between the upper and lower ends, and the tensioner is connected between the lower edge of the flexible support member and the tensioner support.

3. The seat back according to claim 2, wherein, The tensioner includes a base and a pair of arms extending from the base, the base extending along the lower edge of the flexible support member, and each of the arms extending along one of the side edges.

4. The seat back according to claim 3, wherein, Each of the tensioner arms includes an end connected to a respective tensioner support in the tensioner supports.

5. The seat backrest according to claim 4, wherein, The upper edge of the flexible support member defines a recess extending over at least a portion of the upper transverse member of the frame to mount the upper edge of the flexible support member to the frame.

6. A seat back for an office-type chair, comprising: A structural frame having upright members; An armrest support integrally formed with the upright members; An armrest housing vertically adjustably mounted to the armrest support, the armrest housing having an upper end and a lower end; An armrest pad mounted on the upper end; An activation mechanism within the housing, the activation mechanism including a locking element movable between a locked position and an unlocked position, in the locked position, the housing is fixed in place on the armrest support, and in the unlocked position, the housing is vertically adjustable along the armrest support; And An activation portion of the activation mechanism located adjacent the lower end of the housing, the activation portion being connected to the locking element such that movement of the activation portion toward the upper end of the housing causes the locking element to move to the unlocked position.

7. The seat backrest according to claim 6, wherein, The armrest support includes opposing guide rails on which the housing is slidably mounted.

8. The seat back according to claim 7, wherein, The armrest support includes a plurality of vertically spaced notches in which the locking element is positioned when the locking element is in the locked position.

9. The seat back according to claim 8, wherein, The plurality of vertically spaced notches are defined in one of the opposing guide rails.

10. The seat backrest according to claim 8, wherein, The armrest support is integrally molded with the side edge of the backrest.

11. The seat backrest according to claim 10, wherein, The locking element is a pin, and the activation mechanism includes an activation plate movable relative to a retainer plate, wherein the pin extends through an activation slot in the activation plate and a horizontal slot in the retainer plate, and the activation slot is angled relative to the horizontal slot.

12. The seat backrest according to claim 11, comprising a tolerance spring within the housing, the tolerance spring being engaged with at least one of the housing and the guide rail of the armrest support to bias the housing against at least one of the guide rails.

13. The seat back according to claim 12, wherein, The lower end of the housing defines an opening, and wherein the activation portion includes a button positioned within the opening, the button being connected to the locking element such that pressing the button towards the upper end of the housing moves the locking element to the unlocked position.

14. The seat backrest according to claim 13, comprising an activation spring within the housing, the activation spring biasing the button in a direction away from the upper end of the housing.

15. The seat backrest according to claim 14, wherein, The frame includes a pair of upright members spaced apart from each other, each of the upright members including an upper end and a lower end, the frame including a lower transverse member connecting the lower ends of the uprights and an upper transverse member connecting the upper ends.

16. The seat backrest according to claim 15, comprising a flexible support member, the flexible support member including a user support surface having an upper edge, a lower edge, and a pair of side edges, the upper edge of the flexible support member being mounted on the upper transverse member of the frame, the seat backrest including a tensioner connected between the lower edge of the flexible support member and the upright member of the frame such that the tensioner stretches the flexible support member between the upper edge and the lower edge of the flexible support member and maintains the flexible support member in a tensioned state on the frame.

17. A method for constructing a seat backrest, comprising the steps of: providing a flexible support member, the flexible support member including a user support surface having an upper edge, a lower edge, and a pair of side edges; providing a structural frame having a pair of spaced-apart upright members each having an upper end and a lower end, a lower transverse member connecting the lower ends of the uprights, and an upper transverse member connecting the upper ends of the uprights; providing a tensioner arm having a first end and a second end; attaching the first end of the tensioner arm to the lower edge of the flexible support member; mounting the upper edge of the flexible support member to the upper transverse member of the structural frame; engaging the second end of the tensioner arm with one of the upright members of the structural frame; and pivoting the tensioner arm about the second end of the tensioner arm to pull the first end of the tensioner arm towards the structural frame when the tensioner arm is used to stretch the flexible support member between the upper edge and the lower edge of the flexible support member.

18. The method according to claim 17, comprising passing a fastener through the structural frame and the tensioner arm to hold the tensioner arm in place relative to the structural frame.

19. The method according to claim 18, wherein, A pair of tensioner arms are connected to each other by a tensioner base, the tensioner base being connected along the lower edge of the flexible support member, and the tensioner arms each extending along one of the uprights of the structural frame.

20. The method according to claim 19, comprising an abutment projection provided on at least one of the tensioner arms, the abutment projection extending from a second end portion of the tensioner arm and abutting one of the uprights of the structural frame.

Images