Title of Invention	A SEATING UNIT
Abstract	A SEATING UNIT The present invention relates to a seating unit. The seating unit having a base, a seat, and a back, characterized in that a control mechanism having a plurality of flexible supports; said seat pivotally coupled to said control mechanisam; said back pivotally coupled to said control mechanism and said seat; wherein said flexible supports are adapted for mounting to said base in spaced relation to each other and transverse to said base, at least one of said flexible supports positioned at a selected angle relative to vertical and to another of said flexible supports such that flexure of the supports provides synchronous movement of said back and seat.

Title of Invention

A SEATING UNIT

Abstract

A SEATING UNIT The present invention relates to a seating unit. The seating unit having a base, a seat, and a back, characterized in that a control mechanism having a plurality of flexible supports; said seat pivotally coupled to said control mechanisam; said back pivotally coupled to said control mechanism and said seat; wherein said flexible supports are adapted for mounting to said base in spaced relation to each other and transverse to said base, at least one of said flexible supports positioned at a selected angle relative to vertical and to another of said flexible supports such that flexure of the supports provides synchronous movement of said back and seat.

Full Text	FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10) TITLE "SEATING UNIT HAVING MOTION CONTROL" APPLICANT STEELCASE DEVELOPMENT CORPORATION 6100 East Paris Avenue S.E. Caledonia MI 49316 USA Nationality : a US corporation The following specification particularly describes the nature of this invention and the manner in which it is to be performed SEATING UNIT HAVING MOTION CONTROL BACKGROUND OF THE INVENTION The present invention relates to seating units having motion controls, and more particularly relates to a seating unit* having mechanically non-complex motion control elements, but which are efficient and effective. Modern chairs often have backs and seats that move upon recline of a person seated in the chairs. More sophisticated chairs include motion control mechanisms to provide sliding and pivoting motions that move in a particular way relative to the seated user so as to provide an optimally comfortable and adjustable chair motion. However, these mechanisms tend to be sophisticated with rigid pivot end slide elements which can result in complex control mechanisms that have many pieces and are difficult to assemble. In turn, the chair becomes expensive. Further, the mechanisms take up space and can become structurally large in size, which is unacceptable for chairs requiring a thin profile or otherwise requiring a clean unobstructed area under their seat. Also, design of these mechanisms is a complex task, with substantial time required to understand and work out competing functional requirements and physical relationships. Accordingly, a seating unit with motion control mechanism is desired having the aforementioned advantages and solving the aforementioned problems, including having a relatively small, compact mechanism that is flexible and adaptable for different circumstances, and yet that provides a comfortable motion. Alsov a motion control mechanism is desired that is easier to incorporate into chair designs without substantial design time, prototyping, and testing. SUMMARY OF THE PRESENT INVENTION The present invention includes a seating unit having a base that comprises a motion control mechanism adapted for mounting to the base and further having a central area and a plurality of flexible supports. The flexible supports are flexible in a generally fore-to-aft direction, but stiff in a generally vertical direction, and further the flexible supports have end sections projecting generally outward from said central area. A seat is supported on said end sections of at least one of said flexible supports and a back is pivotally connected to said seat at a first pivot connection and pivotally connected to said end sections of at least one other of said flexible supports wherein said flexible supports flex in said generally fore-to-aft direction to provide synchronous movement of said back and seat. Fig. 6 is a side view similar to Fig. 5, but showing the chair in a reclined position; Fig. 7 is a schematic side view of the motion control mechanism shown in Fig. 5; Fig. 8 is an exploded side view of Fig. 5 Fig. 9 is a front view of the flexible supports of the underseat motion control mechanism shown in Fig. 5; Fig. 10 is a top view of Fig. 9, the solid lines showing an at-rest position and the dashed lines showing flexure of the flexible support of Fig. 9; Figs. 10A-10B are enlarged cross-sectional and end views of the outer end of the flexible support of Fig. 5, showing coupling of the outer end to the stationary base frame; Figs. 10C-10D are enlarged cross-sectional and end views similar to Figs. 10A-10B, but showing an alternative embodiment; Fig. 11 is a top view of an alternative motion control mechanism, where the support block is a box-shaped shell and the illustrated flexible support has a resilient bendable center section; Fig. 12 is a top view of an alternative motion control mechanism, where the flexible support is rigid and pivoted to the support block at an inner end, the flexible support being spring-biased toward a home position; Fig. 13 is a top view of a motion control mechanism similar to Fig. 10, and including an adjustable device for changing an effective length of the flexible section of the flexible supports; Fig. 14 is a side view of a modified chair embodying the present invention, the modified chair including a pair of flexible supports and a one-piece bucket forming a back and seat that, upon recline, rotate about an axis aligned near the center of gravity of the seated user; Fig. 14A is a side view of another modified chair similar to Fig. 5, but having a synchronized seat and back motion where the seat moves forward upon recline of the back; Fig. 15 is a perspective view of another modified chair embodying the present invention, the chair including stationary upright side panels, two flexible supports with ends supported by the side panels, and a seat/back bucket mounted to a center of the flexible supports for reclining movement; Figs. 16-17 are top views of a modified motion control mechanism similar to Fig. 2, but where the flexible supports are molded along with the center support block and the seat frame as a one-piece integral molding, Fig. 16 showing the molding in an unstressed such as beams, posts, and attachment plates (whether movable or immovable) are contemplated. The illustrated support 44 includes three mounting areas 45-47. A bottom of the central support 44, near middle mounting area 46 (Fig. 8) includes a tapered bottom recess for mateably engaging a top of the pneumatic spring 43. The mounting areas 45-47 each include an angled surface or slot 45'- 47' for receiving the supports 32. The illustrated front two angled surfaces 45' and 46' (Fig. 5) face forwardly and are angled rearwardly with respect to vertical about 40° to 50°. More preferably, the front angled surface 45' extends at about 46° and the middle angled surface 46' extends at about 42°. The angled surfaces 45' and 46' are nearly parallel, but the middle angled surface 46' has a slightly smaller angle, such that during recline, the end sections 33 of the middle flexible support 32 move upwardly at a slower rate than the end sections 33 of the front flexible support 32. This causes the seat 34 to move translationally and angularly along a predetermined preferred path 48 upon recline, as discussed below. The angled surface 47' faces rearwardly and is tipped forwardly such that it is at a reverse angle to the front angled surfaces 45' and 46', with the surface 47' being at an angle of about 15° to 25° from vertical (with a 20° angle being preferred). It is noted that the angle of the supports 32 can be changed by using replaceable wedge-shaped spacers, such spacer 145 (Figs. 5-7). However, it is desirable to keep the pivot locations (i.e. bearings 52) at the same locations so that the seat and back paths do not unacceptably change away from the intended design upon recline, and so that the supports 32 do not move and flex in a dramatically different way. The illustrated flexible supports 32 (Fig. 9) (also called "flexible beams") are planar leaf-spring-like members. The term "flexible" is used herein to define any fore-aft movement, including bending or pivoting, while the term "resilient" is used herein to mean bending along with energy absorption during flexure. Each support 32 includes an enlarged center section 49 attached to the angled surfaces 45'- 47' by fasteners 50, and further includes resiliency flexible arms 51 that taper in height toward the end sections 33 and that are supported on bearings 52. The bearings 52 (Fig. 9) operably receive the outer ends of the arms 51, such that the outer ends can both slip linearly and also rotate as the arms 51 flex and move. It is contemplated that various connecting arrangements can be made for connecting the ends of the arms 51 to the frames of the seat 34 or back 35. For example, a bearing arrangement 100 (Figs. 10A) includes a polymeric stationary support arms can have a variety of shapes. The illustrated flexible supports 32 have a constant thickness, but it is also contemplated that the thickness may be varied along their length to provide a particular force versus deflection curve upon recline. The illustrated flexible supports 32 are made of spring-steel, but they could be made of. reinforced (or nonreinforced) polymeric materials, composite materials, and other materials as well. Accordingly, flexible supports 32 can be manufactured individually out of flat sheet stock (or molded or otherwise individually formed into more complex shapes) or can be molded into a single structure with central support 44. It should also be noted that flexible supports 32 are stiff, yet resilient and store energy upon flexure in the fore-aft direction in the preferred embodiment. Where pretension is applied to the support 32 to assist in holding the chair in a raised position, the support 32 preferably is made of a material that will not creep, such as spring-steel. Because of the angle of surfaces 45'- 47' and because of the interaction of back frame 60 and seat frame 53 with supports 32, the seat 34 is actually lifted during recline. (Compare Fig. 5 which is the upright position, with Fig. 6, which shows the recline position.) This seat-lifting action helps provide the additionaLenergy necessary when the heavier person reclines. In other words, the energy stored during recline (i.e. due to the seat being lifted) provides some of the energy to assist the seated person when moving from the reclined position toward the upright position. Because the back frame 60 experiences the greatest change in load, it is contemplated that the rearmost flexible support 32 resists flexure the strongest (or, said another way, stores the most energy on recline) while the forwardmost flexible support 32 need not necessarily be as strongly resistant to flexure in the fore-to-aft direction. The illustrated seat 34 (Fig. 8) includes a seat carrier or frame 53 with side sections having front and rear cylindrical recesses 54 for receiving the bearings 52 of the front and middle flexible supports 32. The illustrated frame 53 is U-shaped, and includes side sections 53' defining a perimeter of the seat area. A seat subassembly 55 is attached atop the frame 53, and includes a generally planar, cushioned semi-resilient support 56 extended between the sides of its subframe. It is contemplated that this support can be replaced with a fabric or replaced with a more contoured cushion (whether thick or thin). Thicker or thinner cushions can also be placed on the frame 53. It is also contemplated that other traditional and non-traditional seats can be used on the present invention. center section 77 of the flexible support 32 to resiliently bend and flex when the arms 51 - flex. As can be seen, this causes an effective length of the arms 51 to be "longer", due to flexure of the center area 77 of the flexible support 32. It is noted that the arms 51 themselves may be strong enough to stay straight (see Fig. 11) or may themselves resiliently bend (see Fig, 10). Where resilient leaf-spring-like supports 32 are used, the vertical dimension is large enough relative to its width dimension (i.e. its thickness), so that the vertical beam stiffness is at least about 50 times its lateral bending stiffness. The reason for this 50:1 ratio is so that the supports 32 can cany considerable weight, while allowing fore-aft movement with less force. As this ratio declines, there is less control of the seat and back movement, and a stiffer fore-aft movement, which results in a less controlled feel to a seated user. Fig. 12 illustrates a motion control mechanism utilizing modified flexible supports 32'. The arm sections 51 are relatively stiff and not resilient, but the arms 51 are pivotally mounted to sides of the central support box 78 at pivot locations 80 such that they are flexible. Further, torsion springs 81 could be attached at pivot locations 80 to bias the arms 51 toward their upright positions. (The solid lines illustrate the upright positions, and the dashed lines represent the fully reclined positions.) Fig. 13 illustrates an adjustable back stiffness mechanism 85 attached to the motion control of Fig. 11 instead of to the pivots 66. In the back stiffness mechanism 85, a rotatable gear 86 is attached within the box 78 and is connected to a lever or handle in a convenient location for manipulation by a seated user. A pair of slides 88 and 89 are positioned in the box 78, with their outer end sections 90 extending outward in sliding engagement with the arms 51. The slides 88 and 89 include inner end sections with racks that operably engage the gear 86. As the gear 86 is rotated, the outer end sections 90 are driven outward in direction X. This results in a shorter effective length of the arms 51. This, in turn, dramatically increases the stiffness during recline, since the shortened length of arms 51 must be bent to a much greater extent to reach a fully reclined position. This increased stiffness would support a heavier user during recline. In the description of chairs and motion control components below, components that are similar to or identical to the components of chair 30 are described using the same identification numbers, but with the addition of the letters "A", "B", "C", "D", and "E", respectively. This is done to reduce redundant discussion. down. As a result, the back 60D rotates about axis Dl while the seat 34D rotates forward about axis D2 upon recline. It is contemplated that a chair can also be constructed to include only a single flexible support at a rear of the seat. In such case, the front of the seat Is supported by a sliding bearing arrangement, such as a linear bearing on the seat that slides on a track on the base plate. It is noted that the track can be made linear, curvilinear, or arcuate, as desired. Also, biasing springs can be operably attached to the bearing and/or the seat to assist in biasing the seat (and back) to an upright position. Notably, the flexible supports 32 can be "reversed", with their ends being supported by a stationary member, and their central support 44 being movable upon recline. Chair 30B (Fig. 15) illustrates one such arrangement. It is contemplated that this chair 30B would potentially be useful in a stadium or auditorium or mass transit seating arrangement. Chair 30B includes a pair of spaced-apart stationary side panels 150 secured stably together, such as by connecting rods 151. The flexible supports 32B are positioned with the outer ends of their arms 51B slidably/telescopingly engaging apertures 152 in the panels 150. A central support 44B is attached to a center section of the flexible supports 32B. A seat 34B and back 35B are fixedly attached to the central support 44B. Notably, the back 35B can include a back frame or support panel having some flexibility and compliance for increased comfort. Also, the seat 34B can have a similar flexibility. Side edges of the seat 34B move along a path between and proximate the side panels 150. This helps keep the seat "square" and stable during recline. In another variation, a unitary control construction 160 (Figs. 16-17) is provided where the flexible supports 32C are integrally molded to both the seat frame 161 and the central support 44C. As illustrated, the flexible supports 32C have arms 51C with an S-shaped configuration when viewed from above. As the central support 44C is move, rearwardly upon recline, the arms 51C flex and resiliency bend, temporarily pressing t!u side sections 162 of the seat frame 161 outwardly slightly. Thus, both he flexing of inflexible supports 32C and also the flexing of the side sections 162 provide stored energy 1V-: assisting a seated user to move from a recline position to the upright position. Further since the illustrated assembly is a one-piece molding, manufacturing cost^ are lowered and assembly costs are virtually eliminated in regard to the illustrated components. Notably, the central support 44C includes an angled rear mounting surface 47C where a steel lea! 1. A seating unit having a base, comprising: a motion control adapted for mounting to the base and having a central area and a plurality of flexible supports, said flexible supports being flexible in a generally fore-to-aft direction but stiff in a generally vertical direction, the flexible supports further having end sections projecting generally outward from said central area; a seat supported on said end sections of at least one of said flexible supports; a back pivotally connected to said seat at a first pivot connection and pivotally connected to said end sections of at least one other of said flexible supports; and wherein said flexible supports flex in said generally fore-to-aft direction to provide synchronous movement of said back and seat. 2. The seating unit as set forth in claim 1 wherein said flexible supports have a resilient section and a rigid section. 3. The seating unit as set forth in claim 1 wherein at least one of said flexible supports is resilient. 4. The seating unit as set forth in claim 1 wherein said flexible supports are mounted in spaced relation to each other and generally transverse to said seat, at least one of said flexible supports being positioned at a selected angle relative to vertical, said flexible supports being sufficiently rigid to support said seat while being sufficiently flexible in at least one direction to allow for controlled movement of said seat and back. 5. The seating unit as set forth in claim 1, wherein the seat is pivoted to at least one of the flexible supports by a pivot bushing. 6. The seating unit as set forth in claim 1, wherein the seat is slidably connected to one of the base and flexible supports by a sliding member. 7. The seating unit as set forth in claim 1, wherein at least one of the flexible supports comprises an energy component having a first stiffness property in a vertical direction and a second stiffness property in a fore-aft horizontal direction, a ratio of the first stiffness property to the second stiffness property being at least 50:1. 8. The seating unit as set forth in claim 1 wherein at least one of said flexible. . supports is a leaf spring. 9. The seating unit as set forth in claim 1 wherein at least one of said flexible Osupports is positioned at a selected angle relative to vertical. 10. The seating unit as set forth in claim 9 wherein one of said flexible supports is positioned at an acute angle to another of said flexible supports. 11. The seating unit as set forth in claim 1 wherein each of said flexible supports have a front surface facing in a generally forwardly angled direction. 12. A seating unit having a base, comprising: a seat component; a back component; and a motion control having at least one flexible support and adapted for connection to the base and connected to at least one of said seat and back components, wherein said flexible support has ends that are flexible in a generally fore-to-aft direction but are generally rigid in a vertical direction so that said at least one component is operably supported for said fore-to-aft movement. 13. A motion control mechanism for a seating unit having at least one movable element, comprising: a center support; and a plurality of flexible supports mounted to said center support in spaced relation to each other and generally transverse to said center support, at least one of said flexible supports positioned at a selected angle relative to said center support and to vertical, said flexible supports having end sections configured to support the at least one element of the seating unit, and said flexible supports being sufficiently rigid to support the at least one element of the seating unit while being sufficiently flexible in at least one direction to allow for controlled movement of the at least one element of the seating unit. 14. The motion control mechanism as set forth in claim 13 wherein an energy component separate from said flexible supports provides at least a section of the force to support the movement of said one element. 15. The motion control mechanism as set forth in claim 13, including a mount on the center support that is adjustable for changing the selected angle. 16. The motion control mechanism as set forth in claim 13 wherein at least one of said flexible supports is positioned at a selected angle relative to at least one other flexible support. 17. The motion control mechanism as set forth in claim 13 wherein said flexible supports further include a center section coupled to the center support and to the end sections. 18. The motion control mechanism as set forth in claim 13 wherein said flexible supports are configured to support at least one element of the seating unit in a first and second position, said flexible supports being resilient and adapted to flex into a more loaded condition upon movement of the at least one element from said first position to said second position so as to store energy that is released when the at least one element of the seating unit is returned to said first position. 19. The motion control mechanism set forth in claim 18 wherein an energy component separate from said flexible supports provides a section of the energy to return the at least one element of the seating unit to said first position. 20. The motion control mechanism as set forth in claim 13, wherein at least one of the flexible supports is pivoted to the center support. 21. A seating unit having a base comprising: a control mechanism having a plurality of flexible supports; a seat pivotally coupled to said control mechanism; a back pivotally coupled to said control mechanism and said seat; wherein said flexible supports are adapted for mounting to said base in spaced relation to each other and generally transverse to said base, at least one of said flexible supports positioned at a selected angle relative to vertical and to another of said flexible supports such that flexure of the supports provides synchronous movement of said back and seat. 22. The seating unit as set forth in claim 21 wherein said flexible supports are flexible in a generally fore-to-aft direction but stiff in a generally vertical direction. 23. The seating unit as set forth in claim 21 wherein said flexible supports have a flexible section and a rigid section. 24. The seating unit as set forth in claims 1 or 21 wherein said flexible supports have end sections and a center section. 25. The seating unit as set forth in claim 24 wherein said end sections are flexible and movable, and said center section is rigid. 26. The seating unit as set forth in claim 21 wherein said flexible supports are resilient and form energy components of said control mechanism. 27. The seating unit as set forth in claim 21 wherein the seat is pivotally supported by at least one of the flexible supports by a pivot bushing. 28. The seating unit as set forth in claim 27 wherein said energy components are adapted to flex into a more loaded condition upon recline of said back so as to store energy that is released when said back is pivoted out of the reclined condition. 29. The seating unit as set forth in claim 21 wherein said flexible supports have a front surface facing in a generally forwardly direction. 30. A seating unit having a base comprising: a control mechanism having a plurality of energy components; a seat supported on said energy components; a back pivotally connected to said seat and control mechanism, said energy components being adapted to flex into a more loaded condition upon recline of said back so as to store energy that is released when said back is pivoted out of the reclined condition. 31. . The seating unit as set forth in claims 1, 21 or 30 wherein an energy component separate from said flexible supports provides at least a section of the force to support the synchronous movement of said back and seat. 32. The seating unit as set forth in claim 30, wherein at least one of the energy components has a first stiffness property in a vertical direction and a second stiffness property in a fore-aft horizontal direction, a ratio of the first stiffness property to the second stiffness property being at least 50:1. 33. The seating unit as set forth in claims 7 or 32, wherein the first and second stiffness properties are coefficients of bending stiffness. 34. The seating unit as set forth in claim 30 wherein said energy components are flexible in a generally fore-to-aft direction but stiff in a generally vertical direction. 35. The seating unit as set forth in claim 30 wherein said energy components provide for synchronous motion of said back and seat. 36. The seating unit as set forth in claim 30 wherein said energy components have a flexible section and a rigid section. 37. The seating unit as set forth in claim 30 wherein said energy components have end sections and a center section. 38. The seating unit as set forth in claims 24 or 37 wherein said seat is supported on said end sections. 39. The seating unit as set forth in claims 24 or 37 wherein said end sections are flexible and said center section is rigid. 40. The seating unit as set forth in claims 24 or 37 wherein said end sections are rigid and said center section is flexible. 41. The seating unit as set forth in claim 37, wherein said center section is pivoted to the base. 42. The seating unit as set forth in claim 30 wherein said energy components are mounted to said base in spaced relation to each other and generally transverse to said base, at least one of said energy components having end sections configured to support said seat, said energy components being sufficiently rigid to support said seat while being sufficiently flexible in at least one direction to allow for controlled movement of said seat and back. 43. The seating unit as set forth in claim 30 wherein at least one of said energy components is oriented at an angle relative to another energy component such that said flexure provides for synchronous movement of said back and seat. 44. The seating unit as set forth in claims!,"21 or 43 wherein said synchronous movement includes said seat moving forward as said back is reclined. 45. The seating unit as set forth in claims 1, 21 or 43 wherein said synchronous movement includes said seat moving forwardly and upwardly upon recline of said back. 46. The seating unit as set forth in claim 30 wherein said energy components have a front surface facing in a generally forwardly direction. 47. The seating unit as set forth in claims 11, 29 or 46 wherein said front surfaces are substantially flat. 48. The seating unit as set forth in claims 29 or 46 wherein said front surfaces are oriented at selected angles relative to each other. 49. The seating unit as set forth in claim 30 wherein said energy components have a * cross section in the fore-to-aft direction that is smaller than a vertical height of said energy components. 50. A motion control mechanism for a seating unit, comprising: a center support; and a plurality of flexible supports mounted to said center support, said flexible supports being flexible in a generally fore-to-aft direction but stiff in a generally vertical direction, said energy components having end sections configured to support at least one element of the seating unit, and said flexible supports being sufficiently rigid to support a load on the seating unit while being sufficiently flexible in at least one direction generally transverse to the direction of the load on the seating unit to allow for controlled movement of the seating unit. 51. The motion control mechanism as set forth in claim 50 including an energy component separate from said flexible supports provides at least a section of the force to support the synchronous movement of said back and seat. 52. The motion control mechanism as set forth in claims 13 or 50 wherein said flexible supports have a flexible section and a rigid section. 53. The motion control mechanism as set forth in claim 50 wherein said flexible supports further include a center section. 54. The motion control mechanism as set forth in claim 53 wherein said end sections are flexible and said center section is rigid. 55. The motion control mechanism as set forth in claim 53 wherein said end sections are rigid and said center section is flexible. 56. The motion control mechanism as set forth in claims 13 or 50 wherein said flexible supports are separate elements. 57. The motion control mechanism as set forth in claims 17 or 50 wherein said flexible supports and central area are integrally molded as a one-piece structure. 58. The motion control mechanism as set forth in claim 50 wherein said flexible supports are mounted to said center support in spaced relation to each other and generally transverse to said center support, at least one of said flexible supports positioned at a selected angle relative to said center support. 59. The motion control mechanism as set forth in claim 50 wherein at least one of said flexible supports is positioned at a selected angle relative to at least one other flexible support and to vertical. 60. The motion control mechanism as set forth in claim 50 wherein said flexible supports are selectively positioned relative to said center support and configured to support the at least one element of the seating unit in a first and second position, said flexible supports being resilient and adapted to flex into a more loaded condition upon movement of the at least one element from said first position to said second position so as to store energy that is released when the at least one element of the seating unit is returned to said first position. 61. The motion control mechanism of claim 50 including an energy component separate from the flexible supports provides a section of the energy to return the at least one of the seating units to a first position. 62. The motion control mechanism as set forth in claims 13 or 50 wherein said flexible supports have a front surface facing in a generally forwardly direction. 63. The motion control mechanism as set forth in claim 62 wherein said front surfaces are oriented at selected angles relative to each other. 64. The motion control mechanism as set forth in claims 13 or 50 wherein said flexible supports have a cross section in the fore-to-aft direction that is smaller than the vertical height of said flexible supports. 65. A motion control mechanism for a seating unit having a base and at least one movable element, comprising: a plurality of energy components mounted to said base, said energy components being selectively positioned relative to the base and configured to support the at least one element of the seating unit in a first and second position, said energy components being adapted to flex into a more loaded condition upon movement of the at least one element from said first position to said second position so as to store energy that is released when the at least one element of the seating unit is returned to said first position. 66. The motion control mechanism as set forth in claim 65 including flexible supports separate from said energy components that provide at least a section of the force to support the synchronous movement of said back and seat. 67. The motion control mechanism as set forth in claim 65, wherein at least one of the energy components has a first stiffness property in a vertical direction and a second stiffness property in a fore-aft horizontal direction, a ratio of the first stiffness property to the second stiffness property being at least 50:1. 68. The motion control mechanism as set forth in claim 67, wherein the first and second stiffness properties are coefficients of bending stiffness. 69. The motion control mechanism as set forth in claims 13 or 65 wherein said energy components are flexible in a generally fore-to-aft direction but stiff in a generally vertical direction. 70. The motion control mechanism as set forth in claim 67 wherein said energy components have a resilient section and a rigid section. 71. The motion control mechanism as set forth in claim 65, including a base, and wherein said energy components are separate elements from the base. 72. The motion control mechanism as set forth in claim 65, including a base, and wherein said energy components are integrally molded with the base as a one-piece structure. 73. The motion control mechanism as set forth in claim 65 including flexible supports having end sections and a center section. 74. The motion control mechanism as set forth in claim 73 wherein said end sections support the at least one element of the seating unit. 75. The motion control mechanism as set forth in claims 17 or 73 wherein said end sections are resilient and said center section is rigid. 76. The motion control mechanism as set forth in claims 17 or 73 wherein said end sections are rigid and said center section is resilient. 77. The motion control mechanism as set forth in claim 65 wherein said energy components are mounted to the base in spaced relation to each other and generally transverse to the base, at least one of said energy components having end sections configured to support the at least one element of the seating unit, and said energy components being sufficiently rigid to support the at least one element of the seating unit while being sufficiently flexible in at least one direction to allow for controlled movement of the seating unit. 78. The motion control mechanism as set forth in claim 65 wherein at least one of said energy components is positioned at a selected angle relative to at least one other energy component and to vertical such that said flexure of said energy components provides controlled movement of the seating unit. 79. The motion control mechanism as set forth in claim 65 wherein said energy components have a front surface facing in a generally forwardly direction. 80. The motion control mechanism as set forth in claims 62 or 79 wherein said front surfaces are substantially flat. 81. The motion control mechanism as set forth in claim 79 wherein said front surfaces are oriented at selected angles relative to each other and to vertical. 82. The motion control mechanism as set forth in claim 65 wherein said energy components have a cross section in the fore-to-aft direction that is smaller than the vertical height of said energy components. 83. The motion control mechanism as set forth in claims 13, 50 or 65 wherein said motion control mechanism is adapted for use with an office chair. 84. A seating unit having a base, comprising: a seat component; a back component; and at least one flexible support positioned relative to the base and supporting at least one of said back-and seat components, said flexible support being adapted to flex into a more loaded condition upon movement of the at least one element from a first position to a second position so as to store energy that is released when the at least one component is returned to the first position. 85. The seating unit as set forth in claim 84 wherein said flexible support includes a center section and opposing end sections, with said center being supported on said base, and said opposing end sections supporting said at least one component. 86. The seating unit as set forth in claim 85 wherein said flexible support includes first and second support members that are spaced apart horizontally. 87. The seating unit as set forth in claim 86 wherein said first and second support members each include cross sections that are vertically elongated and that define first and second vertical directions, said first and second vertical directions being non-parallel. 88. The seating unit as set forth in claim 84 wherein said flexible support includes a center section and opposing end sections, with said center coupled to one of said base and said at least one component, and said opposing end sections coupled to said other of said base and said at least one component. 89. The seating unit as set forth in claim 88 wherein said at least one component is said seat. 90. The seating unit as set forth in claim 88 wherein said at least one component is said back. 91. The seating unit as set forth in claim 84 wherein said flexible supports include a resiliency flexible section. 92. The seating unit as set forth in claims 1, 21, 30 or 84 wherein said flexible supports are separate elements. 93. The seating unit as set forth in claim 84 including an energy component separate from said flexible supports provides a section of the energy to return the at least one element of the seating unit to said first position. 94. A seating unit having a base, comprising: a seat component; a back component; and a motion control adapted for connection to the base and having at least one flexible support, the at least one flexible support being connected to at least one of said seat and back components, and including a first flexible support having ends that are flexible in a first direction for allowing movement along the first direction but that are relatively rigid in a perpendicular second direction for preventing movement along the second direction, whereby said at least one component is movable along the first direction but is supported in the second direction and not freely movable along the second direction. 95. The seating unit as set forth in claim 94 wherein the first direction is less than 45° + from horizontal. 96. The seating unit as set forth in claim 94 wherein the at least one flexible support includes a second flexible support that is flexible in a third direction non-parallel the first direction. 97. The seating unit as set forth in claims 12 or 94 wherein said seat component is pivotally connected to said back component. 98. The seating unit as set forth in claims 12 or 94 wherein said at least one flexible support assists in providing synchronous movement of said back component and seat component. 99. The seating unit as set forth in claim 98 wherein said synchronous movement includes said seat component moving forward upon recline of said back component. 100. The seating unit as set forth in claim 98 wherein said synchronous movement includes said seat component moving forwardly and upwardly upon recline of said back component. 101. The seating unit as set forth in claims 12 or 94 wherein said at least one flexible support includes a pair of flexible supports that are mounted to said motion control in spaced relation to each other and generally transverse to said seat component, said flexible supports being sufficiently rigid to support said back component while being sufficiently flexible in at least one direction to allow for controlled movement of said back component. 102. The seating unit as set forth in claims 12 or 94 wherein said at least one flexible support includes a pair of flexible supports that are connected to said base at selected angles relative to each other and to vertical so as to allow for controlled movement of said one component. 103. The seating unit as set forth in claims 12 or 94 wherein said back component is pivotally connected to said at least one flexible support. 104. The seating unit as set forth in claims 1, 12 or 94 wherein at least one of said flexible supports is resilient and comprises an energy component. 105. The seating unit as set forth in claims 12 or 94 wherein said flexible supports include a plurality of separate elements. 106. The seating unit as set forth in claims 1, 12, 21, 37, 84 or 94 wherein said flexible supports and central area are integrally molded as a one-piece structure, 107. The seating unit as set forth in claims 12 or 94 wherein the seat component is pivoted to at least one of the flexible supports by a pivot bushing. 108. The seating unit as set forth in claims 12 or 94 wherein said enerr components are selectively positioned relative to said base and adapted to flex into a mc - loaded condition upon recline of said back component so as to store energy that i? ieased when said back component is pivoted out of the reclined condition. 109. The seating unit as set forth in claims 12 or 94 wherein said at IZL ne flexible supports include a resilient section and a rigid section. 110. The seating unit as set forth in claims 12 or 94 wherein said at lei. :ie flexible supports include a center section and end sections. 111. The seating unit as set forth in claim 110 wherein said flexible su; is include end sections that support said seat component. 112. The seating unit as set forth in claim 110 wherein said flexible supports include end sections that are resilient and said center section is rigid. 113. The seating unit as set forth in claims 24 or 110 wherein said flexible supports include end sections that are rigid and wherein said center section is resilient. 114. The seating unit as set forth in claims 1, 12, 21 or 94 wherein said flexible supports have a cross section in the fore-to-aft direction that is smaller than a vertical height of said flexible supports. 115. The seating unit as set forth in claims 1, 12, 21, 30 or 94 wherein said seating unit is an office chair. 116. A seating unit having a base, comprising: a seat component; a back component; and a motion control having first and second flexible supports each operably connected to at least one of said seat and back components, said first flexible support having first ends that are flexible and movable in a first plane for supporting movement parallel the first plane, and said second flexible support having second ends that are flexible in a second plane different than and non-parallel to the first plane for supporting movement parallel the second plane; the first and second ends of the first and second flexible supports combining to move said at least one component along a complex path caused as the first and second ends move along the non-parallel first and second planes, respectively. 117. The seating unit as set forth in claim 116 wherein the first and second planes are less than 45° from horizontal. 118. The seating unit as set forth in claim 116 wherein the first flexible support is connected to the back component, and the second flexible support is connected to the seat component. 119. The seating unit as set forth in claim 118 wherein the back component is pivoted to the seat component. 120. The seating unit as set forth in claim 116 wherein the base includes legs, and wherein the seating unit forms an office chair. 121. The seating unit as set forth in claim 116 wherein the first flexible support includes a resilient section adapted to resiliency bend and flex to move the ends of the first flexible support along the first plane. 122. A seating unit having a base, comprising: a seat component; a back component; and a motion control adapted for connection to the base and having at least one flexible support, the at least one flexible support being operably connected to at least one of said seat and back components, and includes a first flexible support having opposing arms on opposite sides of the motion control that are independently flexible and independently movable, with ends of the opposing arms being movable different distances, whereby the one component can be moved with a complex motion by flexing the opposing arms different amounts and moving the ends different distances. 123. The seating unit as set forth in claim 122 wherein movement of the ends defines a first plane that extends less than 45° from horizontal. 124. The seating unit as set forth in claim 123 wherein the at least one flexible support includes a second flexible support with second opposing arms on opposite sides of the motion control and that are independently flexible and independently movable. 125. The seating unit as set forth in claim 124 wherein the first and second flexible supports are connected to the back and seat components, respectively. 126. The seating unit as set forth in claim 124 wherein the second opposing arms of the second support are flexible along a second plane that is non-parallel the first plane. 127. The seating unit as set forth in claim 122 wherein the ends are slidably and pivotally connected to the one component. 128. The seating unit as set forth in claim 122 wherein the first flexible support has a resilient section that resiliency bends when one of the opposing ends are moved.

Full Text

FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
COMPLETE SPECIFICATION
(See Section 10)
TITLE
"SEATING UNIT HAVING MOTION CONTROL"
APPLICANT
STEELCASE DEVELOPMENT CORPORATION
6100 East Paris Avenue
S.E. Caledonia
MI 49316
USA
Nationality : a US corporation
The following specification particularly describes the nature of this invention and the manner in which
it is to be performed

SEATING UNIT HAVING MOTION CONTROL
BACKGROUND OF THE INVENTION
The present invention relates to seating units having motion controls, and more particularly relates to a seating unit* having mechanically non-complex motion control elements, but which are efficient and effective.
Modern chairs often have backs and seats that move upon recline of a person seated in the chairs. More sophisticated chairs include motion control mechanisms to provide sliding and pivoting motions that move in a particular way relative to the seated user so as to provide an optimally comfortable and adjustable chair motion. However, these mechanisms tend to be sophisticated with rigid pivot end slide elements which can result in complex control mechanisms that have many pieces and are difficult to assemble. In turn, the chair becomes expensive. Further, the mechanisms take up space and can become structurally large in size, which is unacceptable for chairs requiring a thin profile or otherwise requiring a clean unobstructed area under their seat. Also, design of these mechanisms is a complex task, with substantial time required to understand and work out competing functional requirements and physical relationships.
Accordingly, a seating unit with motion control mechanism is desired having the aforementioned advantages and solving the aforementioned problems, including having a relatively small, compact mechanism that is flexible and adaptable for different circumstances, and yet that provides a comfortable motion. Alsov a motion control mechanism is desired that is easier to incorporate into chair designs without substantial design time, prototyping, and testing.
SUMMARY OF THE PRESENT INVENTION The present invention includes a seating unit having a base that comprises a motion control mechanism adapted for mounting to the base and further having a central area and a plurality of flexible supports. The flexible supports are flexible in a generally fore-to-aft direction, but stiff in a generally vertical direction, and further the flexible supports have end sections projecting generally outward from said central area. A seat is supported on said end sections of at least one of said flexible supports and a back is pivotally connected to said seat at a first pivot connection and pivotally connected to said end sections of at least one other of said flexible supports wherein said flexible supports flex in said generally fore-to-aft direction to provide synchronous movement of said back and seat.

Fig. 6 is a side view similar to Fig. 5, but showing the chair in a reclined position;
Fig. 7 is a schematic side view of the motion control mechanism shown in Fig. 5;
Fig. 8 is an exploded side view of Fig. 5
Fig. 9 is a front view of the flexible supports of the underseat motion control mechanism shown in Fig. 5;
Fig. 10 is a top view of Fig. 9, the solid lines showing an at-rest position and the dashed lines showing flexure of the flexible support of Fig. 9;
Figs. 10A-10B are enlarged cross-sectional and end views of the outer end of the flexible support of Fig. 5, showing coupling of the outer end to the stationary base frame;
Figs. 10C-10D are enlarged cross-sectional and end views similar to Figs. 10A-10B, but showing an alternative embodiment;
Fig. 11 is a top view of an alternative motion control mechanism, where the support block is a box-shaped shell and the illustrated flexible support has a resilient bendable center section;
Fig. 12 is a top view of an alternative motion control mechanism, where the flexible support is rigid and pivoted to the support block at an inner end, the flexible support being spring-biased toward a home position;
Fig. 13 is a top view of a motion control mechanism similar to Fig. 10, and including an adjustable device for changing an effective length of the flexible section of the flexible supports;
Fig. 14 is a side view of a modified chair embodying the present invention, the modified chair including a pair of flexible supports and a one-piece bucket forming a back and seat that, upon recline, rotate about an axis aligned near the center of gravity of the seated user;
Fig. 14A is a side view of another modified chair similar to Fig. 5, but having a synchronized seat and back motion where the seat moves forward upon recline of the back;
Fig. 15 is a perspective view of another modified chair embodying the present invention, the chair including stationary upright side panels, two flexible supports with ends supported by the side panels, and a seat/back bucket mounted to a center of the flexible supports for reclining movement;
Figs. 16-17 are top views of a modified motion control mechanism similar to Fig. 2, but where the flexible supports are molded along with the center support block and the seat frame as a one-piece integral molding, Fig. 16 showing the molding in an unstressed

such as beams, posts, and attachment plates (whether movable or immovable) are contemplated.
The illustrated support 44 includes three mounting areas 45-47. A bottom of the central support 44, near middle mounting area 46 (Fig. 8) includes a tapered bottom recess for mateably engaging a top of the pneumatic spring 43. The mounting areas 45-47 each include an angled surface or slot 45'- 47' for receiving the supports 32. The illustrated front two angled surfaces 45' and 46' (Fig. 5) face forwardly and are angled rearwardly with respect to vertical about 40° to 50°. More preferably, the front angled surface 45' extends at about 46° and the middle angled surface 46' extends at about 42°. The angled surfaces 45' and 46' are nearly parallel, but the middle angled surface 46' has a slightly smaller angle, such that during recline, the end sections 33 of the middle flexible support 32 move upwardly at a slower rate than the end sections 33 of the front flexible support 32. This causes the seat 34 to move translationally and angularly along a predetermined preferred path 48 upon recline, as discussed below. The angled surface 47' faces rearwardly and is tipped forwardly such that it is at a reverse angle to the front angled surfaces 45' and 46', with the surface 47' being at an angle of about 15° to 25° from vertical (with a 20° angle being preferred). It is noted that the angle of the supports 32 can be changed by using replaceable wedge-shaped spacers, such spacer 145 (Figs. 5-7). However, it is desirable to keep the pivot locations (i.e. bearings 52) at the same locations so that the seat and back paths do not unacceptably change away from the intended design upon recline, and so that the supports 32 do not move and flex in a dramatically different way.
The illustrated flexible supports 32 (Fig. 9) (also called "flexible beams") are planar leaf-spring-like members. The term "flexible" is used herein to define any fore-aft movement, including bending or pivoting, while the term "resilient" is used herein to mean bending along with energy absorption during flexure. Each support 32 includes an enlarged center section 49 attached to the angled surfaces 45'- 47' by fasteners 50, and further includes resiliency flexible arms 51 that taper in height toward the end sections 33 and that are supported on bearings 52. The bearings 52 (Fig. 9) operably receive the outer ends of the arms 51, such that the outer ends can both slip linearly and also rotate as the arms 51 flex and move. It is contemplated that various connecting arrangements can be made for connecting the ends of the arms 51 to the frames of the seat 34 or back 35. For example, a bearing arrangement 100 (Figs. 10A) includes a polymeric stationary support

arms can have a variety of shapes. The illustrated flexible supports 32 have a constant thickness, but it is also contemplated that the thickness may be varied along their length to provide a particular force versus deflection curve upon recline. The illustrated flexible supports 32 are made of spring-steel, but they could be made of. reinforced (or nonreinforced) polymeric materials, composite materials, and other materials as well. Accordingly, flexible supports 32 can be manufactured individually out of flat sheet stock (or molded or otherwise individually formed into more complex shapes) or can be molded into a single structure with central support 44. It should also be noted that flexible supports 32 are stiff, yet resilient and store energy upon flexure in the fore-aft direction in the preferred embodiment. Where pretension is applied to the support 32 to assist in holding the chair in a raised position, the support 32 preferably is made of a material that will not creep, such as spring-steel.
Because of the angle of surfaces 45'- 47' and because of the interaction of back frame 60 and seat frame 53 with supports 32, the seat 34 is actually lifted during recline. (Compare Fig. 5 which is the upright position, with Fig. 6, which shows the recline position.) This seat-lifting action helps provide the additionaLenergy necessary when the heavier person reclines. In other words, the energy stored during recline (i.e. due to the seat being lifted) provides some of the energy to assist the seated person when moving from the reclined position toward the upright position. Because the back frame 60 experiences the greatest change in load, it is contemplated that the rearmost flexible support 32 resists flexure the strongest (or, said another way, stores the most energy on recline) while the forwardmost flexible support 32 need not necessarily be as strongly resistant to flexure in the fore-to-aft direction.
The illustrated seat 34 (Fig. 8) includes a seat carrier or frame 53 with side sections having front and rear cylindrical recesses 54 for receiving the bearings 52 of the front and middle flexible supports 32. The illustrated frame 53 is U-shaped, and includes side sections 53' defining a perimeter of the seat area. A seat subassembly 55 is attached atop the frame 53, and includes a generally planar, cushioned semi-resilient support 56 extended between the sides of its subframe. It is contemplated that this support can be replaced with a fabric or replaced with a more contoured cushion (whether thick or thin). Thicker or thinner cushions can also be placed on the frame 53. It is also contemplated that other traditional and non-traditional seats can be used on the present invention.

center section 77 of the flexible support 32 to resiliently bend and flex when the arms 51 - flex. As can be seen, this causes an effective length of the arms 51 to be "longer", due to flexure of the center area 77 of the flexible support 32. It is noted that the arms 51 themselves may be strong enough to stay straight (see Fig. 11) or may themselves resiliently bend (see Fig, 10). Where resilient leaf-spring-like supports 32 are used, the vertical dimension is large enough relative to its width dimension (i.e. its thickness), so that the vertical beam stiffness is at least about 50 times its lateral bending stiffness. The reason for this 50:1 ratio is so that the supports 32 can cany considerable weight, while allowing fore-aft movement with less force. As this ratio declines, there is less control of the seat and back movement, and a stiffer fore-aft movement, which results in a less controlled feel to a seated user.
Fig. 12 illustrates a motion control mechanism utilizing modified flexible supports 32'. The arm sections 51 are relatively stiff and not resilient, but the arms 51 are pivotally mounted to sides of the central support box 78 at pivot locations 80 such that they are flexible. Further, torsion springs 81 could be attached at pivot locations 80 to bias the arms 51 toward their upright positions. (The solid lines illustrate the upright positions, and the dashed lines represent the fully reclined positions.)
Fig. 13 illustrates an adjustable back stiffness mechanism 85 attached to the motion control of Fig. 11 instead of to the pivots 66. In the back stiffness mechanism 85, a rotatable gear 86 is attached within the box 78 and is connected to a lever or handle in a convenient location for manipulation by a seated user. A pair of slides 88 and 89 are positioned in the box 78, with their outer end sections 90 extending outward in sliding engagement with the arms 51. The slides 88 and 89 include inner end sections with racks that operably engage the gear 86. As the gear 86 is rotated, the outer end sections 90 are driven outward in direction X. This results in a shorter effective length of the arms 51. This, in turn, dramatically increases the stiffness during recline, since the shortened length of arms 51 must be bent to a much greater extent to reach a fully reclined position. This increased stiffness would support a heavier user during recline.
In the description of chairs and motion control components below, components that are similar to or identical to the components of chair 30 are described using the same identification numbers, but with the addition of the letters "A", "B", "C", "D", and "E", respectively. This is done to reduce redundant discussion.

down. As a result, the back 60D rotates about axis Dl while the seat 34D rotates forward about axis D2 upon recline.
It is contemplated that a chair can also be constructed to include only a single flexible support at a rear of the seat. In such case, the front of the seat Is supported by a sliding bearing arrangement, such as a linear bearing on the seat that slides on a track on the base plate. It is noted that the track can be made linear, curvilinear, or arcuate, as desired. Also, biasing springs can be operably attached to the bearing and/or the seat to assist in biasing the seat (and back) to an upright position.
Notably, the flexible supports 32 can be "reversed", with their ends being supported by a stationary member, and their central support 44 being movable upon recline. Chair 30B (Fig. 15) illustrates one such arrangement. It is contemplated that this chair 30B would potentially be useful in a stadium or auditorium or mass transit seating arrangement. Chair 30B includes a pair of spaced-apart stationary side panels 150 secured stably together, such as by connecting rods 151. The flexible supports 32B are positioned with the outer ends of their arms 51B slidably/telescopingly engaging apertures 152 in the panels 150. A central support 44B is attached to a center section of the flexible supports 32B. A seat 34B and back 35B are fixedly attached to the central support 44B. Notably, the back 35B can include a back frame or support panel having some flexibility and compliance for increased comfort. Also, the seat 34B can have a similar flexibility. Side edges of the seat 34B move along a path between and proximate the side panels 150. This helps keep the seat "square" and stable during recline.
In another variation, a unitary control construction 160 (Figs. 16-17) is provided where the flexible supports 32C are integrally molded to both the seat frame 161 and the central support 44C. As illustrated, the flexible supports 32C have arms 51C with an S-shaped configuration when viewed from above. As the central support 44C is move, rearwardly upon recline, the arms 51C flex and resiliency bend, temporarily pressing t!u side sections 162 of the seat frame 161 outwardly slightly. Thus, both he flexing of inflexible supports 32C and also the flexing of the side sections 162 provide stored energy 1V-: assisting a seated user to move from a recline position to the upright position. Further since the illustrated assembly is a one-piece molding, manufacturing cost^ are lowered and assembly costs are virtually eliminated in regard to the illustrated components. Notably, the central support 44C includes an angled rear mounting surface 47C where a steel lea!

1. A seating unit having a base, comprising:
a motion control adapted for mounting to the base and having a central area and a plurality of flexible supports, said flexible supports being flexible in a generally fore-to-aft direction but stiff in a generally vertical direction, the flexible supports further having end sections projecting generally outward from said central area;
a seat supported on said end sections of at least one of said flexible supports;
a back pivotally connected to said seat at a first pivot connection and pivotally connected to said end sections of at least one other of said flexible supports; and
wherein said flexible supports flex in said generally fore-to-aft direction to provide synchronous movement of said back and seat.
2. The seating unit as set forth in claim 1 wherein said flexible supports have a
resilient section and a rigid section.
3. The seating unit as set forth in claim 1 wherein at least one of said flexible supports is resilient.
4. The seating unit as set forth in claim 1 wherein said flexible supports are mounted in spaced relation to each other and generally transverse to said seat, at least one of said flexible supports being positioned at a selected angle relative to vertical, said flexible supports being sufficiently rigid to support said seat while being sufficiently flexible in at least one direction to allow for controlled movement of said seat and back.
5. The seating unit as set forth in claim 1, wherein the seat is pivoted to at least one of the flexible supports by a pivot bushing.
6. The seating unit as set forth in claim 1, wherein the seat is slidably connected to one of the base and flexible supports by a sliding member.
7. The seating unit as set forth in claim 1, wherein at least one of the flexible supports comprises an energy component having a first stiffness property in a vertical

direction and a second stiffness property in a fore-aft horizontal direction, a ratio of the first stiffness property to the second stiffness property being at least 50:1.
8. The seating unit as set forth in claim 1 wherein at least one of said flexible. . supports is a leaf spring.
9. The seating unit as set forth in claim 1 wherein at least one of said flexible Osupports is positioned at a selected angle relative to vertical.
10. The seating unit as set forth in claim 9 wherein one of said flexible supports is positioned at an acute angle to another of said flexible supports.
11. The seating unit as set forth in claim 1 wherein each of said flexible supports have a front surface facing in a generally forwardly angled direction.
12. A seating unit having a base, comprising:
a seat component;
a back component; and
a motion control having at least one flexible support and adapted for connection to the base and connected to at least one of said seat and back components, wherein said flexible support has ends that are flexible in a generally fore-to-aft direction but are generally rigid in a vertical direction so that said at least one component is operably supported for said fore-to-aft movement.
13. A motion control mechanism for a seating unit having at least one movable
element, comprising:
a center support; and
a plurality of flexible supports mounted to said center support in spaced relation to each other and generally transverse to said center support, at least one of said flexible supports positioned at a selected angle relative to said center support and to vertical, said flexible supports having end sections configured to support the at least one element of the seating unit, and said flexible supports being sufficiently rigid to support the at least one

element of the seating unit while being sufficiently flexible in at least one direction to allow for controlled movement of the at least one element of the seating unit.
14. The motion control mechanism as set forth in claim 13 wherein an energy component separate from said flexible supports provides at least a section of the force to support the movement of said one element.
15. The motion control mechanism as set forth in claim 13, including a mount on the center support that is adjustable for changing the selected angle.
16. The motion control mechanism as set forth in claim 13 wherein at least one of said flexible supports is positioned at a selected angle relative to at least one other flexible
support.
17. The motion control mechanism as set forth in claim 13 wherein said flexible supports further include a center section coupled to the center support and to the end sections.
18. The motion control mechanism as set forth in claim 13 wherein said flexible supports are configured to support at least one element of the seating unit in a first and second position, said flexible supports being resilient and adapted to flex into a more loaded condition upon movement of the at least one element from said first position to said second position so as to store energy that is released when the at least one element of the seating unit is returned to said first position.

19. The motion control mechanism set forth in claim 18 wherein an energy component separate from said flexible supports provides a section of the energy to return the at least one element of the seating unit to said first position.
20. The motion control mechanism as set forth in claim 13, wherein at least one of the flexible supports is pivoted to the center support.
21. A seating unit having a base comprising:

a control mechanism having a plurality of flexible supports;
a seat pivotally coupled to said control mechanism;
a back pivotally coupled to said control mechanism and said seat; wherein said flexible supports are adapted for mounting to said base in spaced relation to each other and generally transverse to said base, at least one of said flexible supports positioned at a selected angle relative to vertical and to another of said flexible supports such that flexure of the supports provides synchronous movement of said back and seat.
22. The seating unit as set forth in claim 21 wherein said flexible supports are flexible in a generally fore-to-aft direction but stiff in a generally vertical direction.
23. The seating unit as set forth in claim 21 wherein said flexible supports have a flexible section and a rigid section.
24. The seating unit as set forth in claims 1 or 21 wherein said flexible supports have end sections and a center section.
25. The seating unit as set forth in claim 24 wherein said end sections are flexible and movable, and said center section is rigid.
26. The seating unit as set forth in claim 21 wherein said flexible supports are resilient and form energy components of said control mechanism.
27. The seating unit as set forth in claim 21 wherein the seat is pivotally supported by at least one of the flexible supports by a pivot bushing.

28. The seating unit as set forth in claim 27 wherein said energy components are adapted to flex into a more loaded condition upon recline of said back so as to store energy that is released when said back is pivoted out of the reclined condition.
29. The seating unit as set forth in claim 21 wherein said flexible supports have a front surface facing in a generally forwardly direction.

30. A seating unit having a base comprising:
a control mechanism having a plurality of energy components;
a seat supported on said energy components;
a back pivotally connected to said seat and control mechanism, said energy components being adapted to flex into a more loaded condition upon recline of said back so as to store energy that is released when said back is pivoted out of the reclined condition.
31. . The seating unit as set forth in claims 1, 21 or 30 wherein an energy component
separate from said flexible supports provides at least a section of the force to support the
synchronous movement of said back and seat.
32. The seating unit as set forth in claim 30, wherein at least one of the energy components has a first stiffness property in a vertical direction and a second stiffness property in a fore-aft horizontal direction, a ratio of the first stiffness property to the second stiffness property being at least 50:1.
33. The seating unit as set forth in claims 7 or 32, wherein the first and second stiffness properties are coefficients of bending stiffness.
34. The seating unit as set forth in claim 30 wherein said energy components are flexible in a generally fore-to-aft direction but stiff in a generally vertical direction.
35. The seating unit as set forth in claim 30 wherein said energy components provide for synchronous motion of said back and seat.

36. The seating unit as set forth in claim 30 wherein said energy components have a flexible section and a rigid section.
37. The seating unit as set forth in claim 30 wherein said energy components have end sections and a center section.
38. The seating unit as set forth in claims 24 or 37 wherein said seat is supported on said end sections.

39. The seating unit as set forth in claims 24 or 37 wherein said end sections are flexible and said center section is rigid.
40. The seating unit as set forth in claims 24 or 37 wherein said end sections are rigid and said center section is flexible.
41. The seating unit as set forth in claim 37, wherein said center section is pivoted to the base.
42. The seating unit as set forth in claim 30 wherein said energy components are mounted to said base in spaced relation to each other and generally transverse to said base, at least one of said energy components having end sections configured to support said seat, said energy components being sufficiently rigid to support said seat while being sufficiently flexible in at least one direction to allow for controlled movement of said seat and back.
43. The seating unit as set forth in claim 30 wherein at least one of said energy components is oriented at an angle relative to another energy component such that said flexure provides for synchronous movement of said back and seat.
44. The seating unit as set forth in claims!,"21 or 43 wherein said synchronous movement includes said seat moving forward as said back is reclined.
45. The seating unit as set forth in claims 1, 21 or 43 wherein said synchronous movement includes said seat moving forwardly and upwardly upon recline of said back.

46. The seating unit as set forth in claim 30 wherein said energy components have a front surface facing in a generally forwardly direction.
47. The seating unit as set forth in claims 11, 29 or 46 wherein said front surfaces are substantially flat.

48. The seating unit as set forth in claims 29 or 46 wherein said front surfaces are oriented at selected angles relative to each other.
49. The seating unit as set forth in claim 30 wherein said energy components have a
* cross section in the fore-to-aft direction that is smaller than a vertical height of said energy
components.
50. A motion control mechanism for a seating unit, comprising:
a center support; and
a plurality of flexible supports mounted to said center support, said flexible supports being flexible in a generally fore-to-aft direction but stiff in a generally vertical direction, said energy components having end sections configured to support at least one element of the seating unit, and said flexible supports being sufficiently rigid to support a load on the seating unit while being sufficiently flexible in at least one direction generally transverse to the direction of the load on the seating unit to allow for controlled movement of the seating unit.
51. The motion control mechanism as set forth in claim 50 including an energy component separate from said flexible supports provides at least a section of the force to support the synchronous movement of said back and seat.
52. The motion control mechanism as set forth in claims 13 or 50 wherein said flexible supports have a flexible section and a rigid section.
53. The motion control mechanism as set forth in claim 50 wherein said flexible supports further include a center section.
54. The motion control mechanism as set forth in claim 53 wherein said end sections are flexible and said center section is rigid.
55. The motion control mechanism as set forth in claim 53 wherein said end sections
are rigid and said center section is flexible.

56. The motion control mechanism as set forth in claims 13 or 50 wherein said flexible supports are separate elements.
57. The motion control mechanism as set forth in claims 17 or 50 wherein said flexible supports and central area are integrally molded as a one-piece structure.
58. The motion control mechanism as set forth in claim 50 wherein said flexible supports are mounted to said center support in spaced relation to each other and generally transverse to said center support, at least one of said flexible supports positioned at a selected angle relative to said center support.
59. The motion control mechanism as set forth in claim 50 wherein at least one of said flexible supports is positioned at a selected angle relative to at least one other flexible support and to vertical.
60. The motion control mechanism as set forth in claim 50 wherein said flexible supports are selectively positioned relative to said center support and configured to support the at least one element of the seating unit in a first and second position, said flexible supports being resilient and adapted to flex into a more loaded condition upon movement of the at least one element from said first position to said second position so as to store energy that is released when the at least one element of the seating unit is returned to said first position.
61. The motion control mechanism of claim 50 including an energy component separate from the flexible supports provides a section of the energy to return the at least one of the seating units to a first position.

62. The motion control mechanism as set forth in claims 13 or 50 wherein said flexible supports have a front surface facing in a generally forwardly direction.
63. The motion control mechanism as set forth in claim 62 wherein said front surfaces are oriented at selected angles relative to each other.

64. The motion control mechanism as set forth in claims 13 or 50 wherein said flexible supports have a cross section in the fore-to-aft direction that is smaller than the vertical height of said flexible supports.
65. A motion control mechanism for a seating unit having a base and at least one movable element, comprising:
a plurality of energy components mounted to said base, said energy components being selectively positioned relative to the base and configured to support the at least one element of the seating unit in a first and second position, said energy components being adapted to flex into a more loaded condition upon movement of the at least one element from said first position to said second position so as to store energy that is released when the at least one element of the seating unit is returned to said first position.
66. The motion control mechanism as set forth in claim 65 including flexible supports separate from said energy components that provide at least a section of the force to support the synchronous movement of said back and seat.
67. The motion control mechanism as set forth in claim 65, wherein at least one of the energy components has a first stiffness property in a vertical direction and a second stiffness property in a fore-aft horizontal direction, a ratio of the first stiffness property to the second stiffness property being at least 50:1.

68. The motion control mechanism as set forth in claim 67, wherein the first and second stiffness properties are coefficients of bending stiffness.
69. The motion control mechanism as set forth in claims 13 or 65 wherein said energy components are flexible in a generally fore-to-aft direction but stiff in a generally vertical direction.
70. The motion control mechanism as set forth in claim 67 wherein said energy components have a resilient section and a rigid section.

71. The motion control mechanism as set forth in claim 65, including a base, and wherein said energy components are separate elements from the base.
72. The motion control mechanism as set forth in claim 65, including a base, and wherein said energy components are integrally molded with the base as a one-piece
structure.
73. The motion control mechanism as set forth in claim 65 including flexible supports having end sections and a center section.
74. The motion control mechanism as set forth in claim 73 wherein said end sections support the at least one element of the seating unit.
75. The motion control mechanism as set forth in claims 17 or 73 wherein said end sections are resilient and said center section is rigid.
76. The motion control mechanism as set forth in claims 17 or 73 wherein said end sections are rigid and said center section is resilient.
77. The motion control mechanism as set forth in claim 65 wherein said energy components are mounted to the base in spaced relation to each other and generally transverse to the base, at least one of said energy components having end sections configured to support the at least one element of the seating unit, and said energy components being sufficiently rigid to support the at least one element of the seating unit while being sufficiently flexible in at least one direction to allow for controlled movement of the seating unit.
78. The motion control mechanism as set forth in claim 65 wherein at least one of said
energy components is positioned at a selected angle relative to at least one other energy
component and to vertical such that said flexure of said energy components provides
controlled movement of the seating unit.

79. The motion control mechanism as set forth in claim 65 wherein said energy components have a front surface facing in a generally forwardly direction.
80. The motion control mechanism as set forth in claims 62 or 79 wherein said front surfaces are substantially flat.
81. The motion control mechanism as set forth in claim 79 wherein said front surfaces are oriented at selected angles relative to each other and to vertical.
82. The motion control mechanism as set forth in claim 65 wherein said energy components have a cross section in the fore-to-aft direction that is smaller than the vertical height of said energy components.
83. The motion control mechanism as set forth in claims 13, 50 or 65 wherein said motion control mechanism is adapted for use with an office chair.
84. A seating unit having a base, comprising:
a seat component;
a back component; and
at least one flexible support positioned relative to the base and supporting at least one of said back-and seat components, said flexible support being adapted to flex into a more loaded condition upon movement of the at least one element from a first position to a second position so as to store energy that is released when the at least one component is returned to the first position.
85. The seating unit as set forth in claim 84 wherein said flexible support includes a center section and opposing end sections, with said center being supported on said base, and said opposing end sections supporting said at least one component.
86. The seating unit as set forth in claim 85 wherein said flexible support includes first and second support members that are spaced apart horizontally.

87. The seating unit as set forth in claim 86 wherein said first and second support members each include cross sections that are vertically elongated and that define first and second vertical directions, said first and second vertical directions being non-parallel.
88. The seating unit as set forth in claim 84 wherein said flexible support includes a center section and opposing end sections, with said center coupled to one of said base and said at least one component, and said opposing end sections coupled to said other of said base and said at least one component.
89. The seating unit as set forth in claim 88 wherein said at least one component is said seat.
90. The seating unit as set forth in claim 88 wherein said at least one component is said back.
91. The seating unit as set forth in claim 84 wherein said flexible supports include a resiliency flexible section.
92. The seating unit as set forth in claims 1, 21, 30 or 84 wherein said flexible supports are separate elements.
93. The seating unit as set forth in claim 84 including an energy component separate
from said flexible supports provides a section of the energy to return the at least one
element of the seating unit to said first position.
94. A seating unit having a base, comprising:
a seat component;
a back component; and
a motion control adapted for connection to the base and having at least one flexible support, the at least one flexible support being connected to at least one of said seat and back components, and including a first flexible support having ends that are flexible in a first direction for allowing movement along the first direction but that are relatively rigid in a perpendicular second direction for preventing movement along the second direction,

whereby said at least one component is movable along the first direction but is supported in the second direction and not freely movable along the second direction.
95. The seating unit as set forth in claim 94 wherein the first direction is less than 45°
+
from horizontal.
96. The seating unit as set forth in claim 94 wherein the at least one flexible support includes a second flexible support that is flexible in a third direction non-parallel the first direction.
97. The seating unit as set forth in claims 12 or 94 wherein said seat component is pivotally connected to said back component.
98. The seating unit as set forth in claims 12 or 94 wherein said at least one flexible support assists in providing synchronous movement of said back component and seat component.
99. The seating unit as set forth in claim 98 wherein said synchronous movement includes said seat component moving forward upon recline of said back component.
100. The seating unit as set forth in claim 98 wherein said synchronous movement includes said seat component moving forwardly and upwardly upon recline of said back component.

101. The seating unit as set forth in claims 12 or 94 wherein said at least one flexible support includes a pair of flexible supports that are mounted to said motion control in spaced relation to each other and generally transverse to said seat component, said flexible supports being sufficiently rigid to support said back component while being sufficiently flexible in at least one direction to allow for controlled movement of said back component.
102. The seating unit as set forth in claims 12 or 94 wherein said at least one flexible support includes a pair of flexible supports that are connected to said base at selected

angles relative to each other and to vertical so as to allow for controlled movement of said one component.
103. The seating unit as set forth in claims 12 or 94 wherein said back component is pivotally connected to said at least one flexible support.
104. The seating unit as set forth in claims 1, 12 or 94 wherein at least one of said flexible supports is resilient and comprises an energy component.
105. The seating unit as set forth in claims 12 or 94 wherein said flexible supports include a plurality of separate elements.
106. The seating unit as set forth in claims 1, 12, 21, 37, 84 or 94 wherein said flexible supports and central area are integrally molded as a one-piece structure,
107. The seating unit as set forth in claims 12 or 94 wherein the seat component is pivoted to at least one of the flexible supports by a pivot bushing.
108. The seating unit as set forth in claims 12 or 94 wherein said enerr components are selectively positioned relative to said base and adapted to flex into a mc - loaded condition upon recline of said back component so as to store energy that i? ieased when said back component is pivoted out of the reclined condition.

109. The seating unit as set forth in claims 12 or 94 wherein said at IZL ne flexible supports include a resilient section and a rigid section.
110. The seating unit as set forth in claims 12 or 94 wherein said at lei. :ie flexible supports include a center section and end sections.
111. The seating unit as set forth in claim 110 wherein said flexible su; is include end sections that support said seat component.

112. The seating unit as set forth in claim 110 wherein said flexible supports include end sections that are resilient and said center section is rigid.
113. The seating unit as set forth in claims 24 or 110 wherein said flexible supports include end sections that are rigid and wherein said center section is resilient.
114. The seating unit as set forth in claims 1, 12, 21 or 94 wherein said flexible supports have a cross section in the fore-to-aft direction that is smaller than a vertical height of said flexible supports.
115. The seating unit as set forth in claims 1, 12, 21, 30 or 94 wherein said seating unit is an office chair.
116. A seating unit having a base, comprising:
a seat component;
a back component; and
a motion control having first and second flexible supports each operably connected to at least one of said seat and back components, said first flexible support having first ends that are flexible and movable in a first plane for supporting movement parallel the first plane, and said second flexible support having second ends that are flexible in a second plane different than and non-parallel to the first plane for supporting movement parallel the second plane; the first and second ends of the first and second flexible supports combining to move said at least one component along a complex path caused as the first and second ends move along the non-parallel first and second planes, respectively.
117. The seating unit as set forth in claim 116 wherein the first and second planes are less than 45° from horizontal.
118. The seating unit as set forth in claim 116 wherein the first flexible support is connected to the back component, and the second flexible support is connected to the seat component.

119. The seating unit as set forth in claim 118 wherein the back component is pivoted to the seat component.
120. The seating unit as set forth in claim 116 wherein the base includes legs, and wherein the seating unit forms an office chair.
121. The seating unit as set forth in claim 116 wherein the first flexible support includes a resilient section adapted to resiliency bend and flex to move the ends of the first flexible support along the first plane.
122. A seating unit having a base, comprising:
a seat component;
a back component; and
a motion control adapted for connection to the base and having at least one flexible support, the at least one flexible support being operably connected to at least one of said seat and back components, and includes a first flexible support having opposing arms on opposite sides of the motion control that are independently flexible and independently movable, with ends of the opposing arms being movable different distances, whereby the one component can be moved with a complex motion by flexing the opposing arms different amounts and moving the ends different distances.
123. The seating unit as set forth in claim 122 wherein movement of the ends defines a first plane that extends less than 45° from horizontal.
124. The seating unit as set forth in claim 123 wherein the at least one flexible support includes a second flexible support with second opposing arms on opposite sides of the motion control and that are independently flexible and independently movable.
125. The seating unit as set forth in claim 124 wherein the first and second flexible supports are connected to the back and seat components, respectively.
126. The seating unit as set forth in claim 124 wherein the second opposing arms of the second support are flexible along a second plane that is non-parallel the first plane.

127. The seating unit as set forth in claim 122 wherein the ends are slidably and
pivotally connected to the one component.
128. The seating unit as set forth in claim 122 wherein the first flexible support has a
resilient section that resiliency bends when one of the opposing ends are moved.

Documents:

0586-chenp-2005 complete specification as granted.pdf

0586-chenp-2005-abstract.pdf

0586-chenp-2005-claims.pdf

0586-chenp-2005-correspondnece-others.pdf

0586-chenp-2005-description(complete).pdf

0586-chenp-2005-drawings.pdf

0586-chenp-2005-form 1.pdf

0586-chenp-2005-form 18.pdf

0586-chenp-2005-form 3.pdf

0586-chenp-2005-form 5.pdf

0586-chenp-2005-pct.pdf

586-CHENP-2005 ABSTRACT.pdf

586-CHENP-2005 CLAIMS GRANTED.pdf

586-chenp-2005-abstract.jpg

586-chenp-2005.tif

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Patent Number

235231

Indian Patent Application Number

586/CHENP/2005

PG Journal Number

29/2009

Publication Date

17-Jul-2009

Grant Date

26-Jun-2009

Date of Filing

08-Apr-2005

Name of Patentee

STEELCASE INC.,

Applicant Address

901, 44TH STREET, SE, P O BOX 1967, GRAND RAPIDS, MICHIGAN 49501.

Inventors:

#	Inventor's Name	Inventor's Address
1	HEIDMANN, Kurt, R.	6832 LINDEN S.E., GRAND RAPIDS, MI 49548
2	TUBERGEN, Renard, G.	6790 Thornapple River Drive, Alto, MI 49302

PCT International Classification Number

A47C1/024

PCT International Application Number

PCT/US2003/27923

PCT International Filing date

2003-09-08

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10/241,955	2002-09-12	U.S.A.