Drawings
FIG. 1 is a front elevational view of an office chair of the present invention;
FIG. 2 is a side elevational view thereof;
FIG. 3 is a rear elevational view thereof showing the lumbar and pelvic support unit thereof;
FIG. 4 is a front perspective view of the seat;
FIG. 5 is a side cross-sectional view of the seat back assembly showing the lumbar and pelvic support units;
FIG. 6 is an enlarged rear perspective view of the back assembly;
FIG. 7 is an exploded perspective view of a back frame for the back assembly;
FIG. 8 is an enlarged side cross-sectional view of a snap connector arrangement for mounting the backrest assembly on the tilt control mechanism via the pelvic support unit or pusher described herein;
FIG. 9 is a perspective view of an adjustment assembly for the lumbar support unit;
FIG. 10 is an exploded view of the adjustment assembly;
FIG. 11 is a perspective view of a lumbar support unit having a lumbar pad mounted on the adjustment assembly;
FIG. 12 is a perspective view of a lumbar pad;
FIG. 13 is a front view of the lumbar pad;
FIG. 14 is a top view of the lumbar pad;
FIG. 15 is a side view of a lumbar pad;
FIG. 16 is a side cross-sectional view of the lumbar pad taken along line 16-16 of FIG. 13;
FIG. 17 is an enlarged cross-sectional view of the lumbar support unit;
FIG. 18 is an enlarged cross-sectional view of the adjustment assembly;
FIG. 19 is a rear view of a support bracket for the adjustment assembly;
FIG. 20 is a side cross-sectional view of the support bracket taken along line 20-20 of FIG. 19;
FIG. 21 is a front view of the resilient retention plate;
FIG. 22 is a side cross-sectional view of the retention plate taken along line 22-22 of FIG. 21;
FIG. 23 is a front view of an elastic spring plate for the lumbar support unit;
FIG. 24 is a left side view of the spring plate with left side deflection indicated in phantom;
FIG. 25 is a right side view of the spring plate with right side deflection shown in phantom;
FIG. 26 is an enlarged front view of a mounting pocket in a back frame for the pelvic support unit;
fig. 27 is a side cross-sectional view of the connection between the pelvic support unit and the frame mounting pocket;
fig. 28 is a front view of the pelvic support unit;
fig. 29 is a side view of the pelvic support unit;
FIG. 30 is a side cross-sectional view of the pelvic support unit taken along line 30-30 of FIG. 28;
FIG. 31 is a front view of the second embodiment of the lumbar support pad;
FIG. 32 is a top view thereof;
FIG. 33 is a side view thereof;
FIG. 34 is a side cross-sectional view of the lumbar support pad taken along line 34-34 of FIG. 31;
certain terminology will be used in the following description for convenience and for reference only, and is not intended to be limiting. For example, the words "upward," "downward," "rightward," and "leftward" refer to directions within the drawings to which reference is made. The words "inwardly" and "outwardly" will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. The terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.
Detailed Description
Referring to fig. 1-4, the present invention generally relates to an office chair 10 that includes various innovative features therein to accommodate different physical characteristics and comfort preferences of the seat occupant, and that improves the assembly of the chair 10.
Generally, this chair 10 includes an improved height adjustment arm assembly 12 that is easily adjustable. The construction of each ARM ASSEMBLY 12 is disclosed in U.S. provisional patent application serial No.60/657632 entitled ARM ASSEMBLY FOR a CHAIR, filed on 3/1 2005 by Haworth, Inc, which is the common assignee of the present invention. The disclosure of this patent application is incorporated herein by reference in its entirety.
The seat 10 is supported on a base 13 having radial legs 14 supported on the floor by castors 15. The base 13 also includes an upright column 16 which extends vertically and supports a tilt control mechanism 18 at its upper end. The upright 16 has a pneumatic cylinder therein so that the height or elevation of the tilt control mechanism 18 relative to the ground can be adjusted.
The tilt control mechanism 18 includes a control body 19, and a pair of generally L-shaped uprights 20 are pivotally supported by the front ends thereof on the control body 19. The upright members 20 converge rearwardly together to define a connector hub 22 (fig. 3) on which a back frame 23 of a back assembly 24 is supported. The structure FOR this TILT CONTROL MECHANISM 18 is disclosed in U.S. provisional patent application Ser. Nos. 60/657541 and 60/689723, entitled TILT CONTROL MECHANISM FOR A CHAIR, filed by Haworth Inc. at 3/1/2005 and 6/10/2005, and U.S. provisional patent application No.60/657524, entitled TENSION ADJUST MECHANISM FOR A CHAIR, filed by Haworth Inc. at 3/1/2005. The disclosures of these patent applications are incorporated herein by reference in their entirety.
The back assembly 24 has a suspension fabric 25 supported around its periphery on a corresponding periphery of the frame 23 to define a suspension surface 26 for supporting the back of a seat occupant. The construction of the backrest module 24 is disclosed in US provisional patent application No.60/657313 entitled CHAIR BACK, filed on 1/3/2005 by Haworth. The disclosure of this patent application is incorporated herein by reference in its entirety.
To provide additional support to the occupant, the back assembly 24 also includes a lumbar support assembly 28 configured to support the lumbar region of the occupant's back, and may be adjusted to improve the comfort of the support. Likewise, the backrest assembly 24 provides a pelvic support unit 29 disposed at the rear of the pelvic region of the seat occupant.
In addition, seat 10 includes a seating cushion assembly 30 defining an upwardly facing support surface 31 on which the seat cushion of the occupant is supported.
Referring first to the backrest assembly 24 supporting the lumbar support unit 28 and the pelvic support unit 29, the backrest assembly 24 is generally shown in fig. 5-8, wherein the backrest frame 23 includes a pair of vertical side frame rails 35, a top frame rail 36 and a bottom frame rail 37 joined together at upper and lower corners 38, 39 of the backrest assembly 24 so as to define an annular or endless frame having a central opening 40.
As shown in fig. 5-7, the back frame 23 has a contoured shape to ergonomically support the back of an occupant. In particular, the side rails 35 are curved rearward and outward (fig. 1) relative to the bottom portions of the side rails 35 as shown in fig. 2 and 5. In addition, top rail 36 and bottom rail 37 each have a respective curvature to closely conform to the curvature of a typical seat occupant.
To support the occupant, the backrest assembly 24 includes a suspension fabric 25 secured in tension to the frame. In particular, the back frame 23 includes a peripheral splined channel 42 (fig. 1, 5 and 6) in which the periphery of the suspension fabric 25 is secured.
With further reference to fig. 5-7, the back frame 23 generally includes a support structure 43 rigidly interconnected with the side rails 35 and the bottom rail 37. This support structure 43 includes an upright support post 44 that extends along the seat centerline 41 (fig. 1) to a height positioned just below the middle of the side rails 35. The upper end of the support column includes a pair of horizontal support arms 45 extending laterally and having respective outer ends rigidly connected to one of the side rails 35.
The lower end of the support post 44 includes a generally L-shaped connector flange 46 (fig. 5 and 7) that projects forwardly and then downwardly for fixed engagement with the lower transverse rail 37. In addition, this lower column end includes a snap connector 49 projecting downwardly for rigid connection to upright member 20 by a fastening bolt 50 (fig. 8) and a nut 51.
Referring more particularly to the components of the backrest module 24, fig. 7 shows these components in exploded view, with the main frame 23 comprising a rear frame unit 55, the rear frame unit 55 comprising the support structure 43 as described and a rear frame ring 56 supported on the support arms 45 of the support structure 44. The back frame 24 further includes a front frame ring 57 adapted to be mounted on the rear ring 56 in overlying relation so as to define the splined channel 42 about its periphery. In addition, the backrest module 24 includes the suspension fabric 25 and the resilient spline 58 (fig. 7 and 8) as described.
The rear frame unit 55 comprises a support structure 43 and a rear frame ring 56, wherein the support structure 43 and the rear frame ring 56 are simultaneously molded as a single piece construction having the contour shape. To facilitate molding of this contoured shape while also having the splined channel 42 described, the rear frame ring 56 and the front frame ring 57 are molded separately from one another and then secured together.
With reference to the support structure 43, its support post 44 is centrally located within the lower half of the central frame opening 40. The support post 44 has a base end 59 and a pair of post halves 60 and 61 separated from each other by a vertically elongated post slot 62. The post 44 is thus formed as a split post by a slot 62 extending along a substantial portion of the length of the post 44, with the post halves 60 and 61 and the base section 59 together forming a single piece. Thus, the column halves 60 and 61 are supported in cantilevered relation by the base section 59.
The rear frame element 55 and front frame ring 57 are formed of a glass filled nylon material that is molded into the desired shape, wherein this material has limited flexibility such that various regions of the frame flex when placed under load by a seat occupant. With the column halves 60 and 61 separated from each other, these column halves 60 and 61 can be hinged independently of each other to facilitate flexing and movement of the different frame corners 38 and 39. The upper ends of the frame halves 60 and 61 are integrally joined to the transverse arms 45 with the outer ends of the arms 45 extending outwardly and being integrally molded with the vertical sides of the rear frame ring 56.
Within the column base 59, the column base 59 terminates in a bottom wall 65 (fig. 5, 7 and 8) having an aperture 66 formed therein that extends vertically. The bottom wall 65 is also integral with the snap connector 49, wherein an aperture 66 extends vertically through this bottom wall 65 and the snap connector 49, as shown in fig. 8. In coupling the back frame 23 to the seat upright 20, as described in further detail herein, the fasteners 50 extend upwardly from the upright 20 and then through the fastener apertures 66 so that they project perpendicularly above the bottom column wall 65. The upper ends of the fasteners 50 are threadedly engaged by nuts 51, as shown in fig. 8, thereby securing the back frame 23 to the upright members 20.
Also for the bottom column wall 65 depicted in fig. 8, this wall 65 extends forwardly to define the horizontal leg 68 of the L-shaped flange 46, and the flange 46 then turns downwardly to define the vertical leg 69. The bottom column wall section 59 thus serves to rigidly support the bottom transverse rail 37 of the back frame 23. The bottom frame rail 37 is thus supported more rigidly and with less relative movement under the load of the occupant than the middle frame region supported by the support arms 45 and the upper frame corner 38 with the greatest degree of immobility. In this way, the rear frame element 55 provides for controlled flexing of the entire back frame 23.
Referring to fig. 7, the rear frame ring 56 includes top and bottom ring sections 71 and 72 and a vertically extending left and right ring section 73. As shown in fig. 7 and 26, in the middle of the lower ring section 72, a recessed pocket 74 is defined, the recessed pocket 74 being upwardly open and vertically positioned adjacent a circular post 75 (fig. 26), the function of which will be described in further detail below. The pocket 74 is bounded by a side wall 76, the side wall 76 including a notch 77 at a bottom end thereof and adjacent a spline groove 78, the groove 78 being adapted to receive the spline 58.
For the front frame ring 57 (fig. 7), this frame ring has a front surface 80 facing forwardly and a rear surface 81 facing rearwardly toward the rear frame ring 56 and adapted to abut against and be fixedly secured thereto by ultrasonic welding. This frame ring 57 is defined by a vertical ring section 82, a top ring section 83 and a bottom ring section 84. When joined together, front frame ring 57 and rear frame element 55 define back frame 23.
Referring next to the lumbar support unit 28, this unit is generally shown in fig. 5 and 6 and includes an adjustment assembly 90 that extends upwardly from the bottom of the back frame 23 and supports a lumbar support pad 91 on its upper end. The adjustment assembly 90 includes a carrier 92 that is vertically movable for adjusting the height of the lumbar pad 91, and in particular for allowing the occupant to adjust the height of the pad 91 to the most comfortable position along the vertical height of the occupant's back.
The carrier supports resilient support arms 93 which effectively act as leaf springs so that the lumbar pad 91 can float rearwardly in response to movement of the seat occupant, while creating a resistance or reaction to the pressure applied by the seat occupant and the resulting pad movement. In addition, the support arms 93 provide asymmetric support to the lumbar pad 91, allowing one half of the lumbar pad 91 to exert less reaction force and move more easily rearward in response to the occupant than the other half of the lumbar pad 91, which provides more firm support. Thus, bolster 91 provides an adjustable reaction or resistance to motion without mechanical translation or movement of bolster 91 by the occupant. The asymmetric support of the lumbar pad 91 is adjusted by a pair of adjustment cranks 94 and 95 (fig. 6) that are rotatable independently of each other to independently set the support height provided to the left and right halves of the lumbar pad 91 by the support arms 93 for the occupant. Thus, when an occupant sits in the seat, this will stretch the suspension fabric 25 and move the cushion 91 by an amount that can vary depending on the actual size of the occupant.
Referring to fig. 9 and 10, the adjustment assembly 90 generally includes a vertical support bracket 97 adapted to support the carriage 92 for vertical movement as indicated by reference arrow 98 (fig. 9). This carrier 92 has a support arm 93 carried thereon so as to project upwardly therefrom, wherein the upper edge of the support arm 93 includes a pair of hooks 99 which support the lumbar pad 91 as shown in fig. 11.
Referring to fig. 12-16, the lumbar pad 91 has an innovative construction that provides an additional degree of comfort and conformability in addition to the advantages provided by the adjustment assembly 90. More particularly, for this waist pad 91, the pad 91 is molded from a plastic material, preferably PETG copolyester, which provides a suitable degree of elastic flexibility. As described herein, the lumbar pad 91 has a generally rectangular shape defined by concentric support rings 106 and 109 that are radially spaced from one another.
More particularly, the cushion 91 includes a central mounting section 101 that is horizontally elongated and offset from each other relative to a front cushion surface 102. The mounting section 101 has a back wall 103 in which a pair of depending slots 104 are formed as shown in fig. 17, these slots 104 being hooked over respective arm hooks 99, wherein the lower part of this back wall 103 then hangs against the support arm 93. No additional fasteners are required to secure lumbar pad 91 to support arms 93. More particularly, the lumbar pad 91 may be hooked onto the hooks 99 and then pivoted downward to the vertical orientation shown in fig. 17. Although the pad 91 is not limited and can then be pivoted forward for removal, once the pad 91 is positioned in abutting relationship against the opposite back surface of the hanging fabric 25, which fabric 25 prevents pivoting of the pad 91 and removal from the hook 99, such removal is prevented.
While it is known to provide a lumbar pad having a continuous solid construction, the pad 91 of the present invention is defined by a plurality of concentric support rings 106 and 109 extending generally parallel to one another, but radially spaced from one another and offset in the fore-aft direction. Each adjacent pair of loops is joined together by a molded connector web (web) 111 and 114.
The innermost support ring 106 is joined at two locations to opposite ends of the mounting section 101 by webs 111 such that the vertical section of this support ring 106 is joined to the mounting section 101 while the other horizontal ring sections are completely separated from the mounting section 101.
Since both the rings 106 and 111 are molded as a single piece construction, relative reaction forces are always permitted due to the deformation properties of the molding material forming the lumbar pad 91, or relative movement of one ring with respect to the other if moved by the occupant. These concentric rings 106 and 109 are separated from each other along most of their perimeter length to provide a predetermined pressure distribution of variable magnitude to the back of the seat occupant and to allow for greater variation in the cushion surface 102 as the seat occupant's back is pressed rearwardly. In use, the forwardmost outer ring 109 will contact the occupant first and the next successive ring 108 will support the occupant when pressed rearwardly by the occupant. Thus, the rings 106 and 109 successively become effective to support the back of the occupant.
The outer three support rings 107 and 109 are joined to each other by webs 112 and 114. In the upper half of the pad 91, the connector web 112 and 114 are located within the upper left and angled corners 116. However, in the region of the lower corner 117, no such web is provided. Instead, the further webs 119 and 121 are aligned more centrally within the pad 91 and are inclined downwardly and outwardly. The particular lumbar configuration thus described provides more stable support to the lumbar portion of the occupant in the area of the upper corners 16, since the webs 112 and 114 cause the upper corner portions 116 to have a stiffness that is slightly greater than the top of the cushion 91 positioned between the corners 116. In this intermediate region, the horizontal sections of the rings 106 and 109 are completely separated from each other and have greater relative flexibility.
But in the lower corners 117 no webs are provided, making these lower corner portions 117 more flexible, wherein the lower half of the pad 91 is somewhat more rigid in the area of the webs 119 and 121. By selectively placing the webs 111 and 119 and 121, the response of the lumbar pad 91 can be selectively tailored to change the pressure distribution in response to any deformation of the lumbar pad 91 due to contact with the occupant. In addition, the performance characteristics may vary depending on the height, width, placement, and number of webs 111 and 119.
With respect to fig. 16, it is noted that the cross-sectional shape of each of the rings 106 and 109 is uniform and generally rectangular. However, the thickness, cross-sectional shape, and width of the rings 106 and 109 may be varied to vary the responsiveness of the lumbar pads 91.
In addition to the above, it is noted that each of the rings 106 and 109 has a rearward curved portion in the region of the vertical centerline of the waist pad 91 so as to form a central groove 123 (fig. 12 and 14). This central recess 123 is aligned with the spine of the seat occupant and is provided to reduce and preferably eliminate any physical contact of the lumbar pad 91 with the occupant's spine since pressure on the spine is uncomfortable and undesirable.
It will be appreciated that the different connector webs 111 and 119 and 121 are generally diagonally aligned, additional webs may be provided in the area between these locations, and the webs may also be disposed at alternating locations, such as staggered with respect to each other, to provide alternating response properties to the lumbar pad 91.
Likewise, the inner support 106 and 108 are formed as an endless loop. The outermost ring 109 is substantially similar, except that the central portion on the bottom of the lumbar pad 91 is omitted. In particular, the regions of the outer rings 109 between the webs 121 are not provided so that the lumbar pad 91 has a space or gap 124 (fig. 12 and 13) formed therein to provide a clearance space for the pelvic support unit 29 disposed adjacent thereto and within this space when the lumbar pad is in its lowest position. In this position, the pelvic pusher 29 and lumbar pad 91 have some overlap.
Referring next to the adjustment assembly 90, this assembly 90 includes an upright support bracket 97. The support bracket 97 shown in fig. 19 and 20 is formed with a horizontally extending bottom wall 126 having fastener slots 127 in a central portion thereof such that the bottom bracket wall 126 can receive the bolts 50 vertically therethrough, as shown in fig. 8. An additional retainer flange 128 is provided above the bottom wall 126 to receive an edge of the nut 51 therein, as shown in FIG. 8. Thus, the support bracket 97 is rigidly secured to the column bottom end 59, as shown in FIG. 5, and extends vertically therefrom to position the lumbar pad 91 adjacent the suspension fabric 25.
Also for the support bracket 97, this bracket 97 includes a front wall 129 that is generally arcuate and has a pair of side wall sections 130 separated by a vertically elongated guide slot 131. This guide slot 131 cooperates with the carrier 92 as described so that it guides the vertical sliding movement.
The wall section 131 includes a vertical row of teeth 132 that also cooperate with the carrier 92 to selectively maintain the carrier 92 at a selected height while also allowing the carrier 92 to move vertically only by an occupant pushing on the carrier 92.
Referring to fig. 10, the front side of the wall section 10 opposite the ratchet 132 is formed as a vertically elongated slot 133.
To slide the carrier 92, this carrier 92 includes a slide housing 135 that slidingly engages the guide slot 131. Slide housing 135 includes a main wall 136 and a projecting guide portion 137 that is vertically elongated and slidably received within guide slot 131. This guide portion 137 includes a rear wall 38 that projects partially out of the slot 127. As shown in fig. 18, wherein the leading portion 137 is generally cylindrical and defines an interior chamber 139. Additionally, the rear wall 138 has a pair of vertically spaced fastener apertures 140.
Referring to fig. 10 and 18, the front portion of the slide housing 135 is formed with a pair of channels 142 extending vertically and each receiving a fulcrum block (fulrun block) 143 therein. Each fulcrum block 143 is formed generally as a rectangular plate and includes a vertical row of rack teeth 144. As further described herein, the fulcrum block 143 is driven by the adjustment cranks 94 and 95 to adjust the vertical position of the fulcrum block 143 independently of each other.
Slide housing 135 also includes connector slots 146 (fig. 10 and 18) for supporting arms 93. To secure the slide housing 135 to the support bracket 97, a housing cover 148 is provided that defines the exposed outer surface of the carrier 92. The housing cover 148 includes a pair of rearwardly projecting fastening posts 149 adapted to receive fasteners 150 in threaded engagement. These fasteners 150 pass through the retaining plate 151 on the rear side of the support bracket 97 and prevent the slide case 135 from being detached from the support bracket 97.
Referring to fig. 21 and 22, this retention plate 1511 includes a pair of fastener holes 152 into which the fasteners 150 are received. The retaining plate 151 is formed of resilient spring steel and is adapted to engage the teeth 132 in releasable engagement. In particular, the plate 151 includes a pair of cantilevered fingers 153 having arcuate recesses 154 at an upper end thereof for engaging respective rows of teeth 132 spanning the bracket guide slots 131. Thus, the retaining plate 151 prevents the sliding housing 135 from being removed while also engaging the teeth 132 to allow the carrier 92 to slide with sufficient force while also preventing unwanted movement without manual adjustment force. In this way, the carrier 92 is retained on the support bracket 97 and is vertically adjustable. Since the lumbar pad 91 is supported on the carrier via the upright support arms 93, the height of the lumbar pad 91 is adjusted by the movement-dependent carrier 92.
Referring to the elastic support arm 93, the support arm 93 is formed of elastic spring steel so that it can be elastically deflected. The support arm 93 is formed by a cantilevered spring body 157 that supports the connector yoke 156 thereon (fig. 23-25). This connector yoke 156 includes the hook 99 described and is frictionally mounted on the upper end of the spring body 157.
More particularly, and with reference to fig. 23-25, the spring body 157 has a rearwardly projecting locator flange 158 on a bottom edge thereof. As shown in fig. 18, this locator flange 158 is seated within an associated connector slot 146 on the slide housing 135. When positioned therein, the main spring body 157 extends upwardly between the slide housing 135 and the housing cover 148 with the fulcrum block 143 sandwiched between this main spring body 157 and the opposing main wall 136 of the slide housing 135. While the spring body 157 remains vertically stationary, these fulcrum blocks 143 are free to slide vertically as indicated by reference arrows 160 in fig. 18 and 23-25.
For fig. 23, the spring body 157 has a central opening 161 that divides the spring body 157 into plate halves 162 and 163. Each respective fulcrum block 143 cooperates, or is adjacent to and in contacting relationship with, a respective one of the plate halves 162 or 163, with the rack teeth 144 exposed within the opening 161. Thus, each plate half 162 and 163 has one fulcrum block 143 sliding along one surface thereof.
As shown in fig. 18, the upper end 164 of the spring body 157 is able to deflect rearwardly at a location defined above the uppermost edge 165 or 166 of the fulcrum block 143 when the components are assembled together, as shown in phantom. In effect, these upper edges 165 and 166 define a fulcrum or flexion point about which the upper portions of the respective spring halves 161 and 162 can deflect rearwardly.
As shown in FIG. 23, these fulcrum blocks 143 are individually movable and may be vertically offset from each other so that the left and right spring halves 161 and 162 have different bending properties. In particular, the right spring half 163 can bend more easily than the left spring half 162. Thus, when the block 143 is vertically offset, the right spring half 163 is free to bend at the lower bending point as shown in FIG. 25, while the left spring half 162 will bend at a higher position. The upper end of the spring plate 157 includes a separate finger 166 that supports the yoke 156. These fingers 166 also contribute to the asymmetric movement of the lumbar pad 91.
Since this spring plate 156 provides elastic support for the lumbar pad 91, this spring plate 156 thus provides asymmetric support for the lumbar pad and allows the left and right halves of the lumbar pad 91 to have different performance characteristics. In particular, the left spring half 162 provides more resistance to movement of the left half of the lumbar pad 91 as shown, while the right spring half 163 provides less resistance to rearward movement of the right pad half. This resistance is also balanced by aligning the fulcrum blocks 143 with each other.
In order to selectively adjust the vertical positions of these fulcrum blocks 143, adjustment cranks 94 and 95 are provided. These cranks 94 and 95 have spindles 168 that support the head 169 at their outer ends. The inner end of the spindle 168 includes a drive gear 170 having gear teeth 171 extending around a peripheral portion, as shown in fig. 18, wherein the gear 170 rotates in the direction of reference arrow 172. The inner ends of the shafts 168 are rotatably supported on an intermediate support shaft 173, wherein the inner ends of the two shafts 168 are supported by side walls 174 of the slide housing 135.
The drive gears 170 engage the rack teeth 144 on the fulcrum blocks 143 such that rotation of these drive gears 170 causes vertical movement of the blocks 143. While the main shafts 168 are supported on a common support shaft 173, the shafts 168 are independently rotatable from each other so that each adjustment crank 94 or 95 is independently rotatable to adjust the position of one fulcrum block 143 completely independently of the other block 143, as shown in fig. 23-25. In this manner, the seat occupant easily adjusts the asymmetric support provided to the lumbar pad 91 to the most comfortable level without causing movement of the pad 91. This support is provided by the pad 91 to counteract the pressure exerted by the occupant, even without flexing the arm 93 away from the rest position.
In addition to the lumbar support unit 28, a further pelvic support unit 29 is provided, as shown in fig. 26 to 30. More particularly, with respect to the rigid frame pocket 74 formed in the back frame ring 56, this pocket 74 is configured to support the lower end of the outwardly facing pelvic support 175 and is adapted to be pressed against the rear pelvic region of the seat occupant.
Referring to fig. 28-30, the pelvic support or pusher 74 has an enlarged panel 176 supported on a cantilevered support plate 177. The lower end of the support arm 177 is bifurcated to define a tab portion 178 of a pair of legs 179. The distal end of the leg 179 includes a nub 181 that projects laterally or outwardly to engage the notch 77 formed in the mouth 74 of the bag.
Likewise, the lug portion 178 includes a locking notch 182 that is open rearward and defined by a blind hole. When the front and rear frame rings 56 and 57 are secured together by welding (fig. 27), the support opening 74 always opens upwardly from between the interface between the two ring sections 5 and 57. This causes the lug portion 178 of the pelvic support 175 to be inserted downwardly into the pocket opening 74. During this downward insertion, connector legs 179 deflect relatively inward until nubs 181 are aligned with respective pocket notches 77, and then return to their undeflected state, wherein nubs 181 are seated within notches 77.
Because the pelvic support 175 is formed of a resilient deflectable material, such as plastic, the support arms 177 can flex forward during insertion or even for removal, causing the pocket posts 75 to slide upward until it is in alignment with the respective locking notches 182, whereupon the support arms 177 return to their undeflected state with the posts 75 seated within the notches 182. These cooperating components prevent the pelvic support 175 from moving vertically.
Because the resiliently deformable suspension fabric 25 is positioned against the front surface 183 (fig. 5) of the support panel 176, the fabric 25 tends to press rearwardly against the pelvic support 175, so that the stop post 75 most effectively prevents removal of the pelvic support 175. However, because the suspension fabric 25 is also stretchable, the pelvic support 175 can always flex forward to allow it to be removed from the support pocket 74.
The above description relates to the preferred lumbar support unit 28 and pelvic support unit 29. The waist pad 91 may also have an alternating configuration as shown in fig. 31-34.
More particularly, this alternating lumbar pad 200 is substantially similar to lumbar pad 91 except for the overall shape, web location, and web configuration.
More particularly, the lumbar pad 200 includes a central mounting section 201, which in this example includes fastener holes 202, such that the lumbar pad 200 is fixedly attached to a suitable support arm having threaded holes rather than hooks 99. This particular waist pad 200 has an hourglass shape defined by larger outer ends and a narrower central area.
The pad 200 is defined by a plurality of concentric support rings 206 and 209 bonded together in radially spaced relation by connector webs 211 and 214 and further connector webs 219 and 221 and then becomes operative, or comes into supporting contact with the back of the occupant. Thus, when the occupant causes the rings to move rearward, the outer ring 209 is first active and the inner ring then becomes active. With this configuration, the innermost ring 206 is connected to the central section 201 by the pair of connector webs 211 formed substantially similarly to the web 111. In addition, outer support ring 207 and 209 are supported by connector web 212 and 214, with web 212 and 214 extending diagonally outward at pad corner 216.
Pad 200 differs in that connector webs 219 and 221 are positioned diagonally adjacent to each other at the lower corners of pad 200, thus providing responsive performance at substantially similar upper corners 216 and lower corners 217. This also provides greater flexibility in the spinal region of the bottom half of the pad 200, since the connector web 219 and 221 move more outwardly than the connector web 119 and 121.
In addition, the webs 212 and 219 and 221 differ in that they form a mutually curved shape. In contrast to the flatter webs 112 and 119 and 221, these webs 212 and 221 act more as J-springs due to the elasticity of the molding material, thus providing greater elasticity.
Like pad 91, pad 200 also includes a central clearance groove 223 in the spinal region to avoid contact with this portion of the occupant's body.
With the described invention, an improved lumbar pad construction is provided. In addition, an improved arrangement for supporting the lumbar pad is provided, providing misalignment performance by the lumbar pad and providing asymmetric support loads thereon.
Although a particularly preferred embodiment of the invention has been described in detail for purposes of illustration, it will be understood that variations or modifications of the disclosed apparatus, including the reconfiguration of parts, are within the scope of the invention.