CA2017208A1 - Chair - Google Patents
ChairInfo
- Publication number
- CA2017208A1 CA2017208A1 CA 2017208 CA2017208A CA2017208A1 CA 2017208 A1 CA2017208 A1 CA 2017208A1 CA 2017208 CA2017208 CA 2017208 CA 2017208 A CA2017208 A CA 2017208A CA 2017208 A1 CA2017208 A1 CA 2017208A1
- Authority
- CA
- Canada
- Prior art keywords
- seat
- leg portion
- back support
- support
- upper leg
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Abstract
CHAIR
ABSTRACT OF THE DISCLOSURE
A chair comprises an elongated one-piece seat-and-back support bent so as to form a lower substantially U-shaped seat support and an upper substantially upright back support. The seat support includes lower and upper leg portions and a bight portion-intermediate the same. The bight portion is resilient thereby enabling the upper leg portion to deflect downwardly relative to the lower leg portion, and the back support to move downwardly and rearwardly, in response to a downward force exerted on the upper leg portion. In addition, the chair comprises a stabilizer means mounted between the upper and lower leg portions of the seat support for providing stability to the same during downward relative deflection of the upper leg portion. The chair further comprises resilient stiffening means and a tension control means. The stiffening means is mounted to and between the seat support upper and lower leg portions and functions to increase resistance to relative deflection of the upper leg portion. The tension control means is movably mounted relative to the lower leg portion of the seat support for adjustable engagement with the stiffening means to adjust the same's resistance to relative deflection of the seat support upper leg portion.
ABSTRACT OF THE DISCLOSURE
A chair comprises an elongated one-piece seat-and-back support bent so as to form a lower substantially U-shaped seat support and an upper substantially upright back support. The seat support includes lower and upper leg portions and a bight portion-intermediate the same. The bight portion is resilient thereby enabling the upper leg portion to deflect downwardly relative to the lower leg portion, and the back support to move downwardly and rearwardly, in response to a downward force exerted on the upper leg portion. In addition, the chair comprises a stabilizer means mounted between the upper and lower leg portions of the seat support for providing stability to the same during downward relative deflection of the upper leg portion. The chair further comprises resilient stiffening means and a tension control means. The stiffening means is mounted to and between the seat support upper and lower leg portions and functions to increase resistance to relative deflection of the upper leg portion. The tension control means is movably mounted relative to the lower leg portion of the seat support for adjustable engagement with the stiffening means to adjust the same's resistance to relative deflection of the seat support upper leg portion.
Description
r~
THE FIE~D OF l'HE INVENTION
The invention relates to seating and more particularly to chairs having one-piece seat-and-~back supports.
BACRGROUND OF THF INVENTION
Chairs having one-piece seat-and-~ack supports are known. For example, U.S. patent to St. John, 293,813, issued February l9, 1884, discloses a chair comprising an elongated seat-and-back support mounted on a floor-engaging base. The seat-and-back support comprises a lower, rigid, U-shaped seat support and an upper relatively resilient back support extending upwardly froli;ih s~ uppcrt. When a rearward and down~ard force is exerted on the seat-and-back support, the upper back support deflects backwardly and downwardly.
Although the back support of St. John's seat-and-back support is flexible, the seat support thereof is not. Thus, while the back support is designed to deflect downwardly and backwardly relative to the seat support in response to an occupant's weight, the seat support is not so constructed. Such design has been determined to be insufficient in providing the necessary comfort for users, especially in work environments where the chairs are occupied for extended periods of time.
It has thus been found desirable to provide a chair one-piece seat-and-back support comprising a U-shaped seat support with upper and lower leg portions and an int~rmediate bight portion, and a back support with a lower bight portion and an upright back portion, wherein both bight portions are flexible thereby enabling the seat support and the back support to adjust-ably respond at different rates of deflection to an occupant's weight. This chair design has been determined to be most adequate in providing the necessary comfort to the chair occupant.
It has also been found desirable to provide a resilient stiffening means, such a leaf spring, between the upper and lower leg portions of the seat support to strengthen the same and increase resistance to relative deflection of the upper leg portion of ~he seat support.
It should be noted that the use of leaf springs in ~ 72`~
chairs to resist tilting of seat supports are known, although such biasing means have not been used in chairs of the preferred type heretofore described. For example, U.S. patent to Benzing, 3,337,265, issued March 4, 1965, discloses a chair comprising, in relevant part, a pair of inverted U-shaped sides connected by a pair of transverse and longitudinal horizontal supports. A pair of U-shape~ springs are mounted on the transverse supports. A
substantially L-shaped seat-and-back support is mounted on top of the springs. In this manner, when a rearward and downward force is exerted on the seat-and-back support, same reclines downwardly and backwardly against the tension of the springs.
In addition, U.S. patent to Werner, 3,740,792, issued June 26, 1973, discloses a chair comprises a box-like lower housiny open d~ ck' and top portions thereof and mounted on top of a pedestal. An upper seat support is pivotally mounted to the housing on a horizontal shaft. A number of overlapping leaf springs surround the shaft and engage the housing and the seat support. The springs bias the seat support in a horizontal posi-tion. When a downward force is exerted on the seat support, the same pivots against the tension of the springs.
Benzing also provides ~or adjustment of the leaf springs' resistance to deflection of the seat support relative to the housing. Specifically, the tension of the springs is adjusted by turning a lever which displaces the springs forwardly and rearwardly toward and away from the pivotal axis of the seat support to increase the moment arm of the springs and thus vary the tension of the same.
In contrast to the leaf spring tension adjustment-means disclosed by Benzing, it has been found desirable to provide tension adjustment means in a chair having a one-piece seat-and-back support, wherein the adjustment means adjustahly engages the leaf spring along a longitudinal axis thereof to increase and decrease the effective length of the spring to thereby decrease and increase, respectively, the spring's resistance to deflection ~5 of the seat support.
SUMM~RY OF THE INVENTION
A chair comprising a seat, a back, a base and an elongated one-piec~ seat and back support having a substantially U-shaped seat support and a back support. The seat support includes a lower leg portion supported by the base, an upper leg portion supporting the seat an a fir5t bight portion intermediats the upper and lower leg portions. The back support has a second 2 ~ ~
bight portion extending rearwardly and upwardly from the upper leg portion and a back support portion extending upwardly from the second bight portion. The first and second bight portions are resilient thereby enablin~ the upper leg portion and the back support portion to deflect downwardly and downwardly and rearwardly, respectively, in response to forces exerted on the upper leg portion and the upper back portion.
Preferably, the maximum width of t~e upper leg portion is enlarged relative to the maximum width of the second bight portion to provide a relatively broad base of support for the seat against lateral movement thereof and to facilitate relative deflection of the second bight portion. The maximum width of the upper leg portion is preferably equal to at least twice the maximum width of the se~ond-bi~ portion.
In addition, the chair comprises a stabilizer means connected to and between the upper leg portion and the back support portion for providing lateral stability to the back support during relative deflection of the back support portion.
The stabilizer means comprises elongated substantially V-shaped armrests mounted to and between the seat and the back on opposite lateral sides of the chair, each of the armrests being flexible along a portion thereof to accommodate relative deflection of the upper leg portion and the back support.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the accompanying drawings in which:
FIG. 1 is a front perspective view of a chair in accordance with the invention;
FIG. 2 is a rear perspective view of the chair shown in FIG. l;
FIG. 3 is a side elevational view of the chair shown in FIG. l;
FIG. 4 is a side elevational view of the chair shown in FIG. 1 illustrating the chair tilting capabilit~;
FIG. 5 is a perspective view of a support means of the chair and certain elements of a stabilizer means and one embodiment of a tension control means;
FIG. 6 is a detailed side elev~tional YieW of a seat-and-back support of the chair;
FIG. 7 is a bottom view of the seat-and-back support;
FIG. 8 is a fragmented perspective view of a seat support of the seat-and-back support illustrating the stabilizer means and the tension control means;
FIG. 9 is an exploded view of the stabilizer means;
FIG. 10 is a perspective view of a stiffening means of the chair mounted to a cradle of the tension control means;
FIG. 11 is a front elevational view of the stiffening means and the cradle shown in FIG. 10;
FIG. 12 is a side elevational view of a second embodiment of the tension control means;
FIG. 13 is a side elevational view of a third embodiment of the tension control means;
FIG. 14 is an exploded view of an armrest mounting means of the chair; and FIG. 15 is a perspective view o~ th~ ~e_~ir:d embodiment of the tension control means illustrated in FIG. 12.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring generally to the drawings, there is shown a chair 10 comprising a castered base 12, a vertically adjustable pedestal 14 mounted to base 12 and an elongated one-piece seat-and-back support 16 mounted to the pedestal. The seat-and-back support is adapted to deflect downwardly and backwardly against the weight of an occupant. A resilient stiffening means 18 is provided for increasing the seat-and-back support's resistance to deflection. A tension control means 20 is provided for adjusting the tension of the stiffening means 18.
Referring now specifically to Figures 1-5, the chair base 12 comprises a plurality of equidistantly spaced arms 22 having mounted at outer ends 24 thereof floor engaging casters 26. Inner ends 28 of the arms 22 are connected by a central web 30 having a central socket 32 extending therethrough. The base 12 is preferably a one-piece member made of cast aluminum or Zytel (a glass reinforced nylon). Although the base 12 is illustrated as having five arms 22, any other number of arms can be used to provide the necessary support for the chair 10. The illustrated chair base 12 is of a similar type used in connection with a chair manuEactured and sold under the trademark EQUA by Herman Miller, Inc., of Zeeland, Michigan, Applicant's assignee of record. However, other suitable chair bases known in the art may be substituted for the illustrated base 120 The pedestal 14 comprises a lower tube 34 securely received within the web socket 32 of the base 12 and an upper tube 36 above the lower tube and securely rotatably mounting at .
.J~
an upper end 38 thereof a support means 40 preferably made of die cast aluminum. ~ pneumatic air spring 42 is positioned between and partially received within the upper and lower tubes 34, 36 and comprises a piston (not shown) securely mounted to the web 30 5 and a cylinder 44 secured to the support means 40. The air spring 42 includes an adjustment pin 46 projecting upwardly from the upper axial end (not shown) of the cylinder 44 and through a vertical bore (not shown) in the support means 40. The pin 46 is adapted to move between an upper position, where the cylinder and piston of the air spring 42 are helcl stationary in locked engagement, and a lower position, where the cylinder and piston are released for movement relative to each other to extend or contract the air spring longitudinally. The adjustment pin 46 is normally biased in the upper, locked position. ~ height lS adjustment lever 50 is pivotally mounted to the support means 40, engages at an inside end 52 of the lever the adjustment pin 46 and extends outwardly from the casting at the lever outside end 54 at lateral side 56 of the chair 10. When the lever 50 is actuated by lifting upwardly on the outside end of the same, the lever inside end 52 forces the pin 46 to the lower position, thereby releasing the piston (not shown) relative to the cylinder 44 and thus allowing the pedestal 14 to extend or contract to raise or lower the chair upper portion 58. When the lever 50 is released, the pin moves to the upper position and the pedestal 14 becomes locked in the adjusted position. A hand knob 60 is provided at the lever outside end 54 to facilitate manual pivotal actuation of the lever 50.
As shown in Figures 3,4, and 6, the one-piece seat-and-back support 16 is mounted to the pedestal 14 and is bent so as to form a lower generally U-shaped seat support 62 open toward the chair back portion 64 and an upper, somewhat S-shaped back support 66. The seat support 62 comprises upper and lower leg portions 68, 70 and a first bight portion 69 intermediate the leg portions. The back support 66 comprises a second bight portion 73 extending rearwardly and upwardly from the upper leg 68 and an upper back support portion 75 extending upwardly from the second bight portion. The first and second bight portions 69, 73 are resilient and the upper and lower legs 68, 70 and the upper back support portion 75 are somewhat stiff.
The chair seat 72 is mounted on the upper leg portion 68 of the seat support 62. The chair back 74 is mounted on the upper back support portion 75 of the back support 66.
2 ~ ~ 7 ~
As illustrated in Flgures 5-8, the lower leg 70 of the U-shaped seat support 62 forms a downwardly oriented cover 76 at a rear end 71 of the leg. The cover 76 has a rearwardly and downwardly sloping U-shaped side wall 78 and a top wall 80. The cover 76 is complementary to, slidably received on and mounted to the support means 40. Mounting of t:he cover 76 and thus the seat-and-back support 16 to the support means 40 can be achieved by any suitable mechanical means, such as by plurality of bolts 82 in registry with a number of aligned holes 84 and threaded bores 86 of the cover and support casting, respectively. The cover 76 functions to protect elements of the height-adjustable pedestal 14 described above. Elements of the tension control means 20 are similarly protected by the cover 76 as will be described below.
As shown in Figures 3 and 4, when the weight of an occupant is exerted on the seat-and-back support 16, the first and second portions 69, 73 resiliently respond to deflect and move the seat-and-back support downwardly and backwardly between three general degrees of flex: a full upright "work intensive"
position, a partially flexed "relaxed" position, and a "full tilt" position.
In the work intensive position, an occupant exerts minimal force on the back support 66 to impart limited deflection thereof. In the work intensive position, an occupant's weight is exerted downwardly on the chair seat 72, with some deflection of the seat support upper leg 68 relative to the lower leg 70.
In the relaxed position, an occupant is leaned slightly rearwardly exerting some degree of force on the back support 66.
By leaning backwardly, an occupant shifts his/her center of gravity rearwardly away from a pivot point A. Displacement of the center of gravity increases the moment arm about pivot point A, thereby enabling the seat-and-back support 16 to flex rearwardly and downwardl~. The flexing motion causes the S-shaped back support 66 to flatten slightly, thereby increasing the angle formed between the upper leg 68 of the seat support 62 and the back support 66.
Substantially maximum flex of the seat-and-back support 16 is achieved in the full tilt position obtained when an occupant exerts additional pressure on the back support 66. In this position, the outer angle between the seat support upper leg 68 and the back support 66 is maximized by the further downward and rearward seat-and-back support 16 deflection. In the full tilt position, a significant portion of an occupant's upper body weight is shifted to the chair back 74.
There~ore, the elongated one-piece seat-and-back support 16 is adapted to resiliently respond to shifts in an occupant's weight by smoothly flexing at the first and second bight portions 69, 73 thereof from an upright work intensive position to a partially relaxed position to a full tilt position as an occupant shifts his/her weight rearwardly against the back support 66. The novel design of the elongated one-piece flexible seat-and-back support 16 is such that the same is directly responsive to shifts in an occupant's weight to smoothly bend among the various degrees of flex heretofore described, with the upper leg 68 of the seat support 62 deflecting at a rate different from the rate of deflection of the back support 66.
This different deflection rate is due to the differing downward-and rearward load distributions exerted on the seat-and-back support when an occupant sits in the chair. To attain the desired resiliency, the seat-and-back support 16 is preferably made of a glass reinforced nylon resin, a suitable example of which is marketed by the DuPont Company under the trademark Zytel. The seat-and-back support is preferably injection molded from such material. A polyester resin by DuPont sold under the trademark Rynite may also be used.
Referring to FIGS. 1, 2, and 7, the seat support upper leg portion 68 is enlarged or relatively wide with respect to other portions of the seat and back support 16, namely, the first bight portion 69 and the lower leg portion 70 of the seat support 62 and the second bight portion 73 and the upper back support portion 75 of the back support 66. Specifically, the back support portion 75 and the second bight portion 73 of the back support 66 are relatively narrow and each preferably has a width of approximately four inches along substantially the full length thereof. The upper leq portion 68 of the seat support 62 is approximately 10.5 inches in width at a central transverse axis thereof. The upper leg portion tapers as it extends forwardly to the first bight portion 69 which tapers along its length to the lower leg portion 70, the first bight portion having a maximum width of approximately 9.5 inches and an average width of approxima~ely 8.125 inches. The lower leg portion 70 of the seat support also tapers along the length thereof continuing from the first bight portion 69 and has a maximum width of 6.75 inches and an average width of approximately 6 inches.
With respect to the thickness of relevant portions of the seat-and-back support 16, preferably the second bight portion 73 is approximately 0.500 inches in thickness and the upper leg portion 68 has a thickness less than the thickness of the second bight portion. The average thickness of the upper leg portion 68 is approximately .250 inches. The thickness gradient between the second bight portion and the upper leg portion is gradual. In addition, the first bight portion 69 and the lower leg portion also preferably have a thickness of .250 inches.
Given the above-discussed prefered material composition of the seat-and-back support 16, the forgoing dimensions thereof provide the same with sufficient flexibility at the first and second bight portions 69, 73 to achieve desired relative defiection of the upper leg portion 68 and the back support portion 75.
As illustrated in Figures 5, and 7-9, the chair 10 further includes a bridle 88 (hereinafter, sometimes referred to as the "stabilizer means") mounted to and between the upper and lower legs 68, 70 of the seat support 62 and for providing stability to the same during deflection of the seat-and-back support 16. Specifically, the bridle 88 comprises an upper bracket ~0 mounted to the seat support upper leg 68 and a U-shaped stabilizer bracket 92 secured to and between the upper bracket and the support means 40.
The bracket 90 comprises an upper plate 94 and a pair of spaced bilateral flanges 96 preferably formed integral with the plate. The plate 94 is positioned above and mattingly engages the seat support upper leg 68 by a plurality of bolts 98 in registry with aligned holes 100 in the overlapping plate and seat support upper leg. The flanges 96 of the bracket 90 depend downwardly therefrom and are in registry with a pair of spaced slots 102 extending through the seat support upper leg 68.
The U-shaped stabilizer bracket 92 is pivotally mounted to the bracket 90 at upper ends 104 of spaced arms 106 of the stabilizer. To this end, each flange 96 of the bracket go includes a slot 108 forming a pair of spaced legs 110 having a pair of aligned openings 112 extending therethrough. The upper ends 104 of the arms 106 are received in the slots 108 and include holes 114 aligned with the aligned openings 112. A pair of pins 116 extencl through the aligned openings 112 and holes 114 to pivotally mount the stabilizer arms 106 to the bracket 90.
The U-shaped stabilizer bracket 92 is also pivotally mounted at a lower bight portion 118 thereof to the support means 40 in sandwiched relationship between the same and the seat support lower leg 70. To this end, the support means 40 has formed therein a front transverse channel 120 in which a U-shaped, in 5 cross section, shoe 122 complementary to the front transverse channel is received. The bight portion 118 of the stabilizer bracket 92 rotatably engages the shoe 122 and is fully received within the channel 120 such that there is sufficient clearance between the seat support lower leg 70 and the bight portion 118 to permit free rotation of the same with respect to the support means 40. Lower portions 124 of the stabilizer arms 106 are in slidable registry with a pair of`spaced elongated slots 126 extending through the seat support lower leg.
In operation of the one-piece seat-and-back support 16, when an occupant's weight is exerted on the seat support 62, the upper leg 68 thereof deflects downwardly causing the arms 106 of the stabilizer bracket 92 to pivot about their mounting to the flanges 96, the arm lower ends 124 to register to a greater extent with the elongated slots 126 of the seat support lower leg 70 and the stabilizer bracket bight portion 118 to rotate within the front transverse channel 120 of the support means 40. In this manner, the bridle 88 accommodates relative movement of the upper and lower legs 68, 70 of the seat support 62 while at the same time performing its primary functions of resisting separation of the upper and lower legs 68, 70 when the chair 10 is not occupied and providing lateral stability to the U-shaped seat support 62 during flex of the same between the work intensive and full tilt positions.
To adjust the resistance to deflection of the seat-and back support 16 to accommodate occupants differing in weight, the chair 10 is provided with the resilient stiffening means 18 and the tension control means 20. As generally illustrated in Figures 3-5 and 8, the stiffening means 18 comprises an elongated strap-like leaf spring mounted to and between the upper and lower legs 68, 70 of the seat support 62. The geometry of the leaf spring will be hereinafter described in detail. The leaf spring resists downward relative movement of the seat support upper leg 68 when an occupallt's weight i~ exerted thereon. The leaf spring is preferably made of a composite material such as unidirectional S-glass with an epoxy resin (i.e., glass-reinforced epoxy). The tension control means adjusts the leaf spring's resistance to deflection of the seat-and-back support 16. To this end, the tension control means 20 is adapted to adjustably engage the leaf spring along a longitudinal axis thereof to decrease and increase the effective length of the leaf spring to increase and decrease, respectively, the spring~s resistance to relative deflection of 5 the seat-and-back support.
The tension control means 20 generally comprises an engaging means 123 for ad~ustably engaging the leaf spring, a mounting means 125 for movably mounting the engaging means to the support means 40 for movement between front and rear positions relative lo to the leaf spring and an actuating means 127 operably connected to the mounting means for actuating movement of the engaging means between the front and rear positions. In this manner, movement of the engaging means 123 toward the rear position decreases the effective moment arm length between the leaf spring and the force exerted on the rear portion of the seat support by the occupant, thereby increasing the spring's resistance to deflection of the upper leg 70. Movement of the engaging means toward the front position increases the effective moment arm length to thereby decrease the spring's resistance to deflection of the upper leg. In this manner, the resiliency or resistance to deflection of the seat-and-back support 16 can be adjusted to comfortably accommodate occupants varying in weight. It may be surmised that a relatively heavy occupant would adjust the tension control means 20 to a position adjacent the rear position to increase resistance to deflection of the seat-and-back support 16, while an occupant of relatively light weight would set the tension control means closer to the front position to decrease the leaf springls resistance to deflection of the seat-and-back support.
In one embodiment of the invention, illustrated in Figures 5 and 7-11, the resilient stiffening means 18 comprises a substantially bow-shaped leaf spring 128, having upper front and rear portions 130, 132 and a central portion 134. The spring front and rear portions 130, 132 reverse in curvature, the apexes of the curves freely slidably engaging front and back bottom surfaces 136, 138 of the seat support upper leg 68. In addition, the leaf spring 128 is slidably engaged with, at the central portion 13~ thereof, the tension control means 20. The tension control means is slidably mounted to the support means 40 through an elongated opening 140 in the seat support lower leg 70 for movement between the front and rear positions heretofore described.
Referring now specifically to Figures 8 and 10-11 for a detailed discussion of the tension control means 20, the engaging means 123 thereof comprises a cradle 142 slidably mounted to the support means 40 for movement between the front and rear positions heretofore describe~ through the elongated opening 140 in the seat support lower leg 70. The cradle 142 is positioned between the spaced stabili~er arms 106 of the bridle 88 and comprises a substantial U-shaped member having a pair of sidewalls 146, a bottom wall 148 and a transverse pin 150 mounted to and between the sidewalls in spaced relationship to the bottom wall. The bottom wall 148 has depending downwardly therefrom a pair of tangs 152 fixedly secured to the mounting means 125 of the tension control means 20. The leaf spring central portion 134 is captured between the transverse pin 15Q and the cradle bottom wall 148. The cradle transverse pin 150 is preferably fitted with a rubber sleeve 154 and the cradle bottom wall 148 is preferably covered with a rubber sheet 156. The sleeve 154 and the sheet 156 function to eliminate noise otherwise caused by direct movable engagement of the spring center portion 134 with the cradle 142 during operation of the tension control-means and caused by the variable deflection of the spring 128 during usage of the chair 10.
As seen in Figure 5, the mounting means 125 comprises a scissor mechanism 144 slidably mounted to the support means 40 in substantially flush relationship to a top surface 158 thereof and beneath the seat support lower leg 70. The actuating means 127 comprises an adjustment rod 164 rotatably mounted to the support means 40 in substantially flush relationship to th~ same's top surface 58. To this end, the support means 40 has formed in the ~0 top surface 158 thereof rear transverse and longitudinal channels 160, 162. The transverse channel 160 is positioned rearwardly of the front transverse channel 120 associated with the bridle 88.
The adjustment rod 164 is rotatably received within the support means rear transverse channel 160 at an inner end 172 of the rod, the rod outer end 174 extending laterally outwardly from the support means 40 at chair lateral side 176 opposite the height adjustment lever 50. The rod 164 is mounted in rotatable registry with the transverse channel 160 by brackets 178 secured to the support means 40 by any suitable mechanical means, such as by screws 180 in registry with aligned holes (not shown) in the brackets and threaded bores (not shown) in the support means.
The scissor mechanism 144 comprises a block 166, a pair of plates L !~ ~J) ~j ~
168 and a pair of arms 170. The block 166 is slidably received within the longitudinal channel 162 of the support means 40 and includes a pair of shoes 182 in which the tangs 152 of the cradle 142 are securely received. The plates 168 include threaded portions (not shown) operatively engaging the threaded ad~ustment rod 164. Because the plate threaded portions (not shown) and their respective rod threaded portions 184, 186 are oppositely directed, rotation of the adjustment rod in one direction or the other causes the plates to move toward or away from each other.
The arms 170 are pivotally mounted at front and rear ends 188, 190 thereof to and between the plates 168 and the block 166, respectively.
In this manner, when ths adjustment rod 164 is rotated in one direction, the plates 168 move toward each other causil~
the scissor arms 170 to pivot and force the block 166 toward the rear position of the tension control means 20. Rearward movement of the block 166 forces the cradle 142 and leaf spring 128 rearwardly, thereby decreasing the effective moment arm length between the spring and the force exerted by the occupant on the rear portion of the seat support upper leg 68 to increase the spring's resistance to deflection of the seat-and-back support 16. When the rod 164 is rotated in the opposite direction, the plates 168 move away from each other causing the scissor arms 170 to pivot and force the block 166 forwardly. Forward movement of the block 166 forces the cradle 142 and spring 128 forwardly, thereby increasing the effective moment arm length and thereby decreasing the spring's resistance to deflection of the seat-and-back support 16.
To facilitate manual rotation of the adjustment rod 164, the same is provided on the outer end 174 thereof with a hand knob 194. The hand knob 194 preferably differs in geometry from the height adjustment knob 60 so that the knobs can be easily differentiated by an occupant.
As indicated above, certain elements of the tension control means 20 are enclosed by the seat support lower leg cover 76 and are thus protected from damage and accumulation of dust which can affect operation of the tension control means.
In a second embodiment of the invention, illustrated in Figures 12 and 15, the tension control means 20 further comprises a retainer 196 securely mounted to the seat support lower leg 70 and having an open rear portion 198 providing access to the interior of the retainer. The retainer 196 can be formed 2 ~
integrally with the seat support lower leg 70 or be separate therefrom but mounted to the seat support by any suitable mechanical means. The stiffening means 18 comprises a substantially S-shaped leaf spring 200 having an upper curved end 201 freely engaging the seat support upper leg rear part at an apex 202 of the curved end, and a lower substantially straight end 204 received within the retainer 196 through the open rear portion 198 thereof. In this embodiment of the invention, the elements of the tension control means 20 are substantially identical to those of the above-described embodiment except that in the embodiment of Figure 12, a fulcrum pad 206 is mounted to the block 166 rather than the cradle 142. Like the cradle 142, however, the fulcrum pad 206 is set in slidable registry with the elongated opening 140 of the seat support lower leg 70 and includes tangs 152 engaging the shoes 182 of the block 166. The.
pad 206 is set in slidable engagement with a bottom sur.face 208 of the leaf spring straight end 204. In addition, like the cradle 142, the fulcrum pad 206 is adapted to move between the front and rear positions heretofore described to alter the effective length of the leaf spring and-thereby adjust the same's resistance to deflection of the seat-and-back support 16.
SpecificalIy, upon rotation of the adjustment rod 164 in one direction, the fulcrum pad 206 moves rearwardly to shorten the effective moment arm length between the spring and occupant downward force and thereby increase the spring's resistance to relative downward movement of the seat support upper leg 68.
When the fulcrum pad 206 is moved toward the front position of the tension control means, the moment arm is increased, thereby decreasing the springls resistance to downward relative movement of the seat support upper leg 6~. Consequently, when a relatively light occupant uses the chair, the fulcrum pad 206 is positioned adjacent the front position of the tension control means 20. Alternatively, when a heavy occupant uses the chair 10, the fulcrum pad 206 is positioned closer to the rear posi-tion of the~ tension control means 20.
In a third embodiment of the invention, illustrated inFigure 13, the stiffening means 20 comprises a substantially straight leaf spring 210 having the lower front end 212 thereof fixedly secured to the seat support lower leg front part 21~ by any suitable mechanical means, such as by a plurality of bolts 216 in registry with an equal number of pairs of aligned holes (not shown) extending through the spring front end 212 and the ?, .~ ~
lo~er leg front part 214. An upper rear end 220 of the leaf spring 210 is bent along a gradual curve, the apex 222 of which freely mattingly engages the seat support upper leg rear part 138.
In the tension control means 20 of the embodiment illustrated in Figure 13 the engaging means 123 comprises a cam pad 224 mounted about a horizontal axis of rotation on a pin 226 forming the mounting means 125 and rotatably secured transversely to and between opposing sidewalls 78 of the seat support lower leg cover 76. The cam pad 224 is set in registry with an enlarged opening 228 extending throuyh the seat support lower leg 70 and an enlarged channel 229 within and the support means 40.
The cam pad 224 engages a bottom surface 230 of the leaf spring 210 at a rear part 232 of the pad. The cam pad 224 is somewhat triangular in shape, with the rear end 232 thereof being enlarged relative to a front end 234 of the pad. Due to this geometry, rotation of the same in one direction causes the pad to move rearwardly and upwardly and to engage the spring lower front portion 212 to a greater extent to thereby shorten the effective moment arm length between the spring and the force exerted on the seat by the occupant and thereby increase the spring's resistance to deflection of the seat support upper leg 68. Rotation of the pad 224 in the other direction moves the same forwardly and downwardly to thereby increase the moment arm length and reduce the spring's resistence to deflection.
The actuating means 127 comprises an adjustment shaft 26 threada~ly mounted to the support means 40 through a vertical threaded bore (not shown) of the same, and has a lower end 238 extending downwardly from the support means and mounting a handwheel 240 and an upper end 242 above the casting and in abutting engagement with the cam pad rear end 232.
In operation, rotation of the handwheel 240 in one direction threads the adjustment shaft 236 upwardly to force the cam pad 224 about its pivot axis and rearwardly and upwardly against the leaf spring lower front end 212. The effective length of the leaf spring 210 is thereby decreased to therefore increase the spring's resistance to deflection of the seat support upper leg 68. Conversely, upon rotation of the handwheel 240 in the other direction, the shaft 236 is adjusted downwardly to lower the rear portion 232 of the cam pad 224 to thereby increase the effective length of the spring 210 and decrease the same's resistance to deflection of the upper leg 68.
?~
Referring now to Figures 1-3 and 7, the chair seat 72 comprises an inner shell (not shown) and an outer structural shell (not shown) and is mounted to and above the seat support upper leg 68 by any suitable mechanical means, such as by a plurality of screws (not shown) in registry with aligned holes 246 extending through the seat outer shell and the seat support upper leg. The shape of the seat 72 is complementary to that of the seat support 62, but enlarged with respect thereto to provide the necessary comfort and support to the occupant. In addition, the seat front portion 248 is rolled over to comfortably accommodate an occupant's legs. A cushion 250 is molded to the top of the inner shell. The inner shell is removably fastened by any suitable snap means to the outer shell. By this me~hod, the seat cushion 250 can be replaced as necessary. The seat 72 is preferably made of Zytel or polypropylene, compositions which provide some degree of flexibility to the seat during flex of the seat-and-back support 16.
As illustrated in Figures 1-3 the chair back 74 is substantially half oval in shape and has an enlarged U-shaped channel 252 within a central relief portion 254 formed on a rear surface 256 of the back. The back 74 comprises an inner and an outer shell (not shown), the outer shell being securely fastened to the back support 66, with the same received within the chan nel 252 and flush with respect to the relief portion 254 by any suitable mechanical means, such as by a plurality of screws (not shown) extending through aligned orifices (not shown) in the back and the back support. Like the chair seat 72, the back 74 is preferably made of a material such as Zytel or polypropylene to provide flexibility of the back. The chair back 74 is enlarged with respect to the back support and in this manner functions to distribute the weight transferred from the occupant to the chair seat and back support as the occupant leans rearwardly in the same between the upright and full tilt positions. A cushion 262 is molded to the inner shell, the same being removably fastened by any suitable snap means to the outer shell. By this method, the back cushion 262 can be replaced as necessary.
As illustrated in Figures 1-3, the chair can be provided with a pair of op~ional armrests 264 mounted on opposite lateral sides 56, 176 of the chair 10. Specifically, each armrest 264 is a substantially V-shaped flexible member having, with reference to the work intensive position of the seat-and-back support 16, a substantially horizontal leg 266 and a diagonal leg 26~, free 1 f '.~
ends of the horizontal and diagonal legs being ro-tatably mounted to the back 74 and the seat 72, respectively, at a lateral side 56 or 176 of the chair. The horizontal leg 266 provides support for an occupant's arm. In this manner, as the seat-and-back support 16 flexes downwardly and backwardly in response to a shift in an occupant's weight, the armrests 264 likewise flex thereby accommodating the changing geometry of the seat-and-back support. Flex of the V-shaped armrests generally occurs at the vertices 270 of the Vs, due to the rotatable connection be-tween the armrests and the seat 72 and back 74. Each armrest 264 is substantially rectangular, in cross section, with the thickness thereo~ tapering substantially at the vertex 270 of the V. A
reduction of thickness at the vertex facilitates the resiliency of the armrest 264.
As stated above, the armrests 264 are rotatably mounted to the chair back 74 and the chair seat 72 at lateral sides 56, 176 of the chair 10. To this end, the free ends 272, 274 of the horizontal and diagonal legs 266, 268, respectively, have formed thereon sockets 276. In addition, an attachment means 278 is provided for mounting the armrests 264 to the seat 72 and the back 74.
As best seen in Figure 14, the armrest attachment means 278 comprises a pair of U-shaped brackets 280, each having a web portion 282 and a pair of side portions 28~. Each side portion 284 includes a hole 286 extending therethrough. One bracket 280 is securely mounted to and between the chair back shells, with the web portion 282 sandwiched therebetween and the side portions 284 extending rearwardly of the chair. A recess in the inner chair back shell (not shown~ accommodates the bracket web. The other bracket 280 is mounted to and between the chair seat shells, the web portion 282 sandwiched therebetween and the side portions 284 extending downwardly from the chair seat 72. A
recess in the inner chair s at shell (not shown) accommodates the bracket web.
The attachment means 278 further comprises a hollow tubular spacer 288 partially received within each armrest socket 276, the spacer being aligned with a respective hole 286 in the U--shaped bracket 280. Bolts 290 extend through the aligned sockets 276, spacers 288 and holes 286 to securely mount the armrest 264 to the brackets 280. Hemispherical protective caps 292 can be placed over the bolts 290.
As stated above, the chair 10 comprises the first 2~ 7~
stabilizer means or bridle 88 pivotally mounted to and between the upper and lower leg portions 68, 70 of the seat support 62 for providing stability to the same during deflection of the upper leg 68 relative to the lower leg by virtue of the resilient first bight portion 69 intermediate the same.
In a similar manner, the armrests 264 also function as stabilizer means for the seat and back support 16, but not with respect to the upper and lower legs 68, 70 thereof. Rather, by virtue of the pivotal connection of the armrests 264 to and between the seat 70 and the back 74, on opposite lateral sides 56, 76 of the chair, the armrests provide lateral stability to the seat and back support 16 between the upper leg portion 68 and the upper back support portion 75 during relative deflection thereof by virtue of the resilient second bight portion 73.
While the invention has been described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. To the contrary, I intend to cover all alternative modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
THE FIE~D OF l'HE INVENTION
The invention relates to seating and more particularly to chairs having one-piece seat-and-~back supports.
BACRGROUND OF THF INVENTION
Chairs having one-piece seat-and-~ack supports are known. For example, U.S. patent to St. John, 293,813, issued February l9, 1884, discloses a chair comprising an elongated seat-and-back support mounted on a floor-engaging base. The seat-and-back support comprises a lower, rigid, U-shaped seat support and an upper relatively resilient back support extending upwardly froli;ih s~ uppcrt. When a rearward and down~ard force is exerted on the seat-and-back support, the upper back support deflects backwardly and downwardly.
Although the back support of St. John's seat-and-back support is flexible, the seat support thereof is not. Thus, while the back support is designed to deflect downwardly and backwardly relative to the seat support in response to an occupant's weight, the seat support is not so constructed. Such design has been determined to be insufficient in providing the necessary comfort for users, especially in work environments where the chairs are occupied for extended periods of time.
It has thus been found desirable to provide a chair one-piece seat-and-back support comprising a U-shaped seat support with upper and lower leg portions and an int~rmediate bight portion, and a back support with a lower bight portion and an upright back portion, wherein both bight portions are flexible thereby enabling the seat support and the back support to adjust-ably respond at different rates of deflection to an occupant's weight. This chair design has been determined to be most adequate in providing the necessary comfort to the chair occupant.
It has also been found desirable to provide a resilient stiffening means, such a leaf spring, between the upper and lower leg portions of the seat support to strengthen the same and increase resistance to relative deflection of the upper leg portion of ~he seat support.
It should be noted that the use of leaf springs in ~ 72`~
chairs to resist tilting of seat supports are known, although such biasing means have not been used in chairs of the preferred type heretofore described. For example, U.S. patent to Benzing, 3,337,265, issued March 4, 1965, discloses a chair comprising, in relevant part, a pair of inverted U-shaped sides connected by a pair of transverse and longitudinal horizontal supports. A pair of U-shape~ springs are mounted on the transverse supports. A
substantially L-shaped seat-and-back support is mounted on top of the springs. In this manner, when a rearward and downward force is exerted on the seat-and-back support, same reclines downwardly and backwardly against the tension of the springs.
In addition, U.S. patent to Werner, 3,740,792, issued June 26, 1973, discloses a chair comprises a box-like lower housiny open d~ ck' and top portions thereof and mounted on top of a pedestal. An upper seat support is pivotally mounted to the housing on a horizontal shaft. A number of overlapping leaf springs surround the shaft and engage the housing and the seat support. The springs bias the seat support in a horizontal posi-tion. When a downward force is exerted on the seat support, the same pivots against the tension of the springs.
Benzing also provides ~or adjustment of the leaf springs' resistance to deflection of the seat support relative to the housing. Specifically, the tension of the springs is adjusted by turning a lever which displaces the springs forwardly and rearwardly toward and away from the pivotal axis of the seat support to increase the moment arm of the springs and thus vary the tension of the same.
In contrast to the leaf spring tension adjustment-means disclosed by Benzing, it has been found desirable to provide tension adjustment means in a chair having a one-piece seat-and-back support, wherein the adjustment means adjustahly engages the leaf spring along a longitudinal axis thereof to increase and decrease the effective length of the spring to thereby decrease and increase, respectively, the spring's resistance to deflection ~5 of the seat support.
SUMM~RY OF THE INVENTION
A chair comprising a seat, a back, a base and an elongated one-piec~ seat and back support having a substantially U-shaped seat support and a back support. The seat support includes a lower leg portion supported by the base, an upper leg portion supporting the seat an a fir5t bight portion intermediats the upper and lower leg portions. The back support has a second 2 ~ ~
bight portion extending rearwardly and upwardly from the upper leg portion and a back support portion extending upwardly from the second bight portion. The first and second bight portions are resilient thereby enablin~ the upper leg portion and the back support portion to deflect downwardly and downwardly and rearwardly, respectively, in response to forces exerted on the upper leg portion and the upper back portion.
Preferably, the maximum width of t~e upper leg portion is enlarged relative to the maximum width of the second bight portion to provide a relatively broad base of support for the seat against lateral movement thereof and to facilitate relative deflection of the second bight portion. The maximum width of the upper leg portion is preferably equal to at least twice the maximum width of the se~ond-bi~ portion.
In addition, the chair comprises a stabilizer means connected to and between the upper leg portion and the back support portion for providing lateral stability to the back support during relative deflection of the back support portion.
The stabilizer means comprises elongated substantially V-shaped armrests mounted to and between the seat and the back on opposite lateral sides of the chair, each of the armrests being flexible along a portion thereof to accommodate relative deflection of the upper leg portion and the back support.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the accompanying drawings in which:
FIG. 1 is a front perspective view of a chair in accordance with the invention;
FIG. 2 is a rear perspective view of the chair shown in FIG. l;
FIG. 3 is a side elevational view of the chair shown in FIG. l;
FIG. 4 is a side elevational view of the chair shown in FIG. 1 illustrating the chair tilting capabilit~;
FIG. 5 is a perspective view of a support means of the chair and certain elements of a stabilizer means and one embodiment of a tension control means;
FIG. 6 is a detailed side elev~tional YieW of a seat-and-back support of the chair;
FIG. 7 is a bottom view of the seat-and-back support;
FIG. 8 is a fragmented perspective view of a seat support of the seat-and-back support illustrating the stabilizer means and the tension control means;
FIG. 9 is an exploded view of the stabilizer means;
FIG. 10 is a perspective view of a stiffening means of the chair mounted to a cradle of the tension control means;
FIG. 11 is a front elevational view of the stiffening means and the cradle shown in FIG. 10;
FIG. 12 is a side elevational view of a second embodiment of the tension control means;
FIG. 13 is a side elevational view of a third embodiment of the tension control means;
FIG. 14 is an exploded view of an armrest mounting means of the chair; and FIG. 15 is a perspective view o~ th~ ~e_~ir:d embodiment of the tension control means illustrated in FIG. 12.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring generally to the drawings, there is shown a chair 10 comprising a castered base 12, a vertically adjustable pedestal 14 mounted to base 12 and an elongated one-piece seat-and-back support 16 mounted to the pedestal. The seat-and-back support is adapted to deflect downwardly and backwardly against the weight of an occupant. A resilient stiffening means 18 is provided for increasing the seat-and-back support's resistance to deflection. A tension control means 20 is provided for adjusting the tension of the stiffening means 18.
Referring now specifically to Figures 1-5, the chair base 12 comprises a plurality of equidistantly spaced arms 22 having mounted at outer ends 24 thereof floor engaging casters 26. Inner ends 28 of the arms 22 are connected by a central web 30 having a central socket 32 extending therethrough. The base 12 is preferably a one-piece member made of cast aluminum or Zytel (a glass reinforced nylon). Although the base 12 is illustrated as having five arms 22, any other number of arms can be used to provide the necessary support for the chair 10. The illustrated chair base 12 is of a similar type used in connection with a chair manuEactured and sold under the trademark EQUA by Herman Miller, Inc., of Zeeland, Michigan, Applicant's assignee of record. However, other suitable chair bases known in the art may be substituted for the illustrated base 120 The pedestal 14 comprises a lower tube 34 securely received within the web socket 32 of the base 12 and an upper tube 36 above the lower tube and securely rotatably mounting at .
.J~
an upper end 38 thereof a support means 40 preferably made of die cast aluminum. ~ pneumatic air spring 42 is positioned between and partially received within the upper and lower tubes 34, 36 and comprises a piston (not shown) securely mounted to the web 30 5 and a cylinder 44 secured to the support means 40. The air spring 42 includes an adjustment pin 46 projecting upwardly from the upper axial end (not shown) of the cylinder 44 and through a vertical bore (not shown) in the support means 40. The pin 46 is adapted to move between an upper position, where the cylinder and piston of the air spring 42 are helcl stationary in locked engagement, and a lower position, where the cylinder and piston are released for movement relative to each other to extend or contract the air spring longitudinally. The adjustment pin 46 is normally biased in the upper, locked position. ~ height lS adjustment lever 50 is pivotally mounted to the support means 40, engages at an inside end 52 of the lever the adjustment pin 46 and extends outwardly from the casting at the lever outside end 54 at lateral side 56 of the chair 10. When the lever 50 is actuated by lifting upwardly on the outside end of the same, the lever inside end 52 forces the pin 46 to the lower position, thereby releasing the piston (not shown) relative to the cylinder 44 and thus allowing the pedestal 14 to extend or contract to raise or lower the chair upper portion 58. When the lever 50 is released, the pin moves to the upper position and the pedestal 14 becomes locked in the adjusted position. A hand knob 60 is provided at the lever outside end 54 to facilitate manual pivotal actuation of the lever 50.
As shown in Figures 3,4, and 6, the one-piece seat-and-back support 16 is mounted to the pedestal 14 and is bent so as to form a lower generally U-shaped seat support 62 open toward the chair back portion 64 and an upper, somewhat S-shaped back support 66. The seat support 62 comprises upper and lower leg portions 68, 70 and a first bight portion 69 intermediate the leg portions. The back support 66 comprises a second bight portion 73 extending rearwardly and upwardly from the upper leg 68 and an upper back support portion 75 extending upwardly from the second bight portion. The first and second bight portions 69, 73 are resilient and the upper and lower legs 68, 70 and the upper back support portion 75 are somewhat stiff.
The chair seat 72 is mounted on the upper leg portion 68 of the seat support 62. The chair back 74 is mounted on the upper back support portion 75 of the back support 66.
2 ~ ~ 7 ~
As illustrated in Flgures 5-8, the lower leg 70 of the U-shaped seat support 62 forms a downwardly oriented cover 76 at a rear end 71 of the leg. The cover 76 has a rearwardly and downwardly sloping U-shaped side wall 78 and a top wall 80. The cover 76 is complementary to, slidably received on and mounted to the support means 40. Mounting of t:he cover 76 and thus the seat-and-back support 16 to the support means 40 can be achieved by any suitable mechanical means, such as by plurality of bolts 82 in registry with a number of aligned holes 84 and threaded bores 86 of the cover and support casting, respectively. The cover 76 functions to protect elements of the height-adjustable pedestal 14 described above. Elements of the tension control means 20 are similarly protected by the cover 76 as will be described below.
As shown in Figures 3 and 4, when the weight of an occupant is exerted on the seat-and-back support 16, the first and second portions 69, 73 resiliently respond to deflect and move the seat-and-back support downwardly and backwardly between three general degrees of flex: a full upright "work intensive"
position, a partially flexed "relaxed" position, and a "full tilt" position.
In the work intensive position, an occupant exerts minimal force on the back support 66 to impart limited deflection thereof. In the work intensive position, an occupant's weight is exerted downwardly on the chair seat 72, with some deflection of the seat support upper leg 68 relative to the lower leg 70.
In the relaxed position, an occupant is leaned slightly rearwardly exerting some degree of force on the back support 66.
By leaning backwardly, an occupant shifts his/her center of gravity rearwardly away from a pivot point A. Displacement of the center of gravity increases the moment arm about pivot point A, thereby enabling the seat-and-back support 16 to flex rearwardly and downwardl~. The flexing motion causes the S-shaped back support 66 to flatten slightly, thereby increasing the angle formed between the upper leg 68 of the seat support 62 and the back support 66.
Substantially maximum flex of the seat-and-back support 16 is achieved in the full tilt position obtained when an occupant exerts additional pressure on the back support 66. In this position, the outer angle between the seat support upper leg 68 and the back support 66 is maximized by the further downward and rearward seat-and-back support 16 deflection. In the full tilt position, a significant portion of an occupant's upper body weight is shifted to the chair back 74.
There~ore, the elongated one-piece seat-and-back support 16 is adapted to resiliently respond to shifts in an occupant's weight by smoothly flexing at the first and second bight portions 69, 73 thereof from an upright work intensive position to a partially relaxed position to a full tilt position as an occupant shifts his/her weight rearwardly against the back support 66. The novel design of the elongated one-piece flexible seat-and-back support 16 is such that the same is directly responsive to shifts in an occupant's weight to smoothly bend among the various degrees of flex heretofore described, with the upper leg 68 of the seat support 62 deflecting at a rate different from the rate of deflection of the back support 66.
This different deflection rate is due to the differing downward-and rearward load distributions exerted on the seat-and-back support when an occupant sits in the chair. To attain the desired resiliency, the seat-and-back support 16 is preferably made of a glass reinforced nylon resin, a suitable example of which is marketed by the DuPont Company under the trademark Zytel. The seat-and-back support is preferably injection molded from such material. A polyester resin by DuPont sold under the trademark Rynite may also be used.
Referring to FIGS. 1, 2, and 7, the seat support upper leg portion 68 is enlarged or relatively wide with respect to other portions of the seat and back support 16, namely, the first bight portion 69 and the lower leg portion 70 of the seat support 62 and the second bight portion 73 and the upper back support portion 75 of the back support 66. Specifically, the back support portion 75 and the second bight portion 73 of the back support 66 are relatively narrow and each preferably has a width of approximately four inches along substantially the full length thereof. The upper leq portion 68 of the seat support 62 is approximately 10.5 inches in width at a central transverse axis thereof. The upper leg portion tapers as it extends forwardly to the first bight portion 69 which tapers along its length to the lower leg portion 70, the first bight portion having a maximum width of approximately 9.5 inches and an average width of approxima~ely 8.125 inches. The lower leg portion 70 of the seat support also tapers along the length thereof continuing from the first bight portion 69 and has a maximum width of 6.75 inches and an average width of approximately 6 inches.
With respect to the thickness of relevant portions of the seat-and-back support 16, preferably the second bight portion 73 is approximately 0.500 inches in thickness and the upper leg portion 68 has a thickness less than the thickness of the second bight portion. The average thickness of the upper leg portion 68 is approximately .250 inches. The thickness gradient between the second bight portion and the upper leg portion is gradual. In addition, the first bight portion 69 and the lower leg portion also preferably have a thickness of .250 inches.
Given the above-discussed prefered material composition of the seat-and-back support 16, the forgoing dimensions thereof provide the same with sufficient flexibility at the first and second bight portions 69, 73 to achieve desired relative defiection of the upper leg portion 68 and the back support portion 75.
As illustrated in Figures 5, and 7-9, the chair 10 further includes a bridle 88 (hereinafter, sometimes referred to as the "stabilizer means") mounted to and between the upper and lower legs 68, 70 of the seat support 62 and for providing stability to the same during deflection of the seat-and-back support 16. Specifically, the bridle 88 comprises an upper bracket ~0 mounted to the seat support upper leg 68 and a U-shaped stabilizer bracket 92 secured to and between the upper bracket and the support means 40.
The bracket 90 comprises an upper plate 94 and a pair of spaced bilateral flanges 96 preferably formed integral with the plate. The plate 94 is positioned above and mattingly engages the seat support upper leg 68 by a plurality of bolts 98 in registry with aligned holes 100 in the overlapping plate and seat support upper leg. The flanges 96 of the bracket 90 depend downwardly therefrom and are in registry with a pair of spaced slots 102 extending through the seat support upper leg 68.
The U-shaped stabilizer bracket 92 is pivotally mounted to the bracket 90 at upper ends 104 of spaced arms 106 of the stabilizer. To this end, each flange 96 of the bracket go includes a slot 108 forming a pair of spaced legs 110 having a pair of aligned openings 112 extending therethrough. The upper ends 104 of the arms 106 are received in the slots 108 and include holes 114 aligned with the aligned openings 112. A pair of pins 116 extencl through the aligned openings 112 and holes 114 to pivotally mount the stabilizer arms 106 to the bracket 90.
The U-shaped stabilizer bracket 92 is also pivotally mounted at a lower bight portion 118 thereof to the support means 40 in sandwiched relationship between the same and the seat support lower leg 70. To this end, the support means 40 has formed therein a front transverse channel 120 in which a U-shaped, in 5 cross section, shoe 122 complementary to the front transverse channel is received. The bight portion 118 of the stabilizer bracket 92 rotatably engages the shoe 122 and is fully received within the channel 120 such that there is sufficient clearance between the seat support lower leg 70 and the bight portion 118 to permit free rotation of the same with respect to the support means 40. Lower portions 124 of the stabilizer arms 106 are in slidable registry with a pair of`spaced elongated slots 126 extending through the seat support lower leg.
In operation of the one-piece seat-and-back support 16, when an occupant's weight is exerted on the seat support 62, the upper leg 68 thereof deflects downwardly causing the arms 106 of the stabilizer bracket 92 to pivot about their mounting to the flanges 96, the arm lower ends 124 to register to a greater extent with the elongated slots 126 of the seat support lower leg 70 and the stabilizer bracket bight portion 118 to rotate within the front transverse channel 120 of the support means 40. In this manner, the bridle 88 accommodates relative movement of the upper and lower legs 68, 70 of the seat support 62 while at the same time performing its primary functions of resisting separation of the upper and lower legs 68, 70 when the chair 10 is not occupied and providing lateral stability to the U-shaped seat support 62 during flex of the same between the work intensive and full tilt positions.
To adjust the resistance to deflection of the seat-and back support 16 to accommodate occupants differing in weight, the chair 10 is provided with the resilient stiffening means 18 and the tension control means 20. As generally illustrated in Figures 3-5 and 8, the stiffening means 18 comprises an elongated strap-like leaf spring mounted to and between the upper and lower legs 68, 70 of the seat support 62. The geometry of the leaf spring will be hereinafter described in detail. The leaf spring resists downward relative movement of the seat support upper leg 68 when an occupallt's weight i~ exerted thereon. The leaf spring is preferably made of a composite material such as unidirectional S-glass with an epoxy resin (i.e., glass-reinforced epoxy). The tension control means adjusts the leaf spring's resistance to deflection of the seat-and-back support 16. To this end, the tension control means 20 is adapted to adjustably engage the leaf spring along a longitudinal axis thereof to decrease and increase the effective length of the leaf spring to increase and decrease, respectively, the spring~s resistance to relative deflection of 5 the seat-and-back support.
The tension control means 20 generally comprises an engaging means 123 for ad~ustably engaging the leaf spring, a mounting means 125 for movably mounting the engaging means to the support means 40 for movement between front and rear positions relative lo to the leaf spring and an actuating means 127 operably connected to the mounting means for actuating movement of the engaging means between the front and rear positions. In this manner, movement of the engaging means 123 toward the rear position decreases the effective moment arm length between the leaf spring and the force exerted on the rear portion of the seat support by the occupant, thereby increasing the spring's resistance to deflection of the upper leg 70. Movement of the engaging means toward the front position increases the effective moment arm length to thereby decrease the spring's resistance to deflection of the upper leg. In this manner, the resiliency or resistance to deflection of the seat-and-back support 16 can be adjusted to comfortably accommodate occupants varying in weight. It may be surmised that a relatively heavy occupant would adjust the tension control means 20 to a position adjacent the rear position to increase resistance to deflection of the seat-and-back support 16, while an occupant of relatively light weight would set the tension control means closer to the front position to decrease the leaf springls resistance to deflection of the seat-and-back support.
In one embodiment of the invention, illustrated in Figures 5 and 7-11, the resilient stiffening means 18 comprises a substantially bow-shaped leaf spring 128, having upper front and rear portions 130, 132 and a central portion 134. The spring front and rear portions 130, 132 reverse in curvature, the apexes of the curves freely slidably engaging front and back bottom surfaces 136, 138 of the seat support upper leg 68. In addition, the leaf spring 128 is slidably engaged with, at the central portion 13~ thereof, the tension control means 20. The tension control means is slidably mounted to the support means 40 through an elongated opening 140 in the seat support lower leg 70 for movement between the front and rear positions heretofore described.
Referring now specifically to Figures 8 and 10-11 for a detailed discussion of the tension control means 20, the engaging means 123 thereof comprises a cradle 142 slidably mounted to the support means 40 for movement between the front and rear positions heretofore describe~ through the elongated opening 140 in the seat support lower leg 70. The cradle 142 is positioned between the spaced stabili~er arms 106 of the bridle 88 and comprises a substantial U-shaped member having a pair of sidewalls 146, a bottom wall 148 and a transverse pin 150 mounted to and between the sidewalls in spaced relationship to the bottom wall. The bottom wall 148 has depending downwardly therefrom a pair of tangs 152 fixedly secured to the mounting means 125 of the tension control means 20. The leaf spring central portion 134 is captured between the transverse pin 15Q and the cradle bottom wall 148. The cradle transverse pin 150 is preferably fitted with a rubber sleeve 154 and the cradle bottom wall 148 is preferably covered with a rubber sheet 156. The sleeve 154 and the sheet 156 function to eliminate noise otherwise caused by direct movable engagement of the spring center portion 134 with the cradle 142 during operation of the tension control-means and caused by the variable deflection of the spring 128 during usage of the chair 10.
As seen in Figure 5, the mounting means 125 comprises a scissor mechanism 144 slidably mounted to the support means 40 in substantially flush relationship to a top surface 158 thereof and beneath the seat support lower leg 70. The actuating means 127 comprises an adjustment rod 164 rotatably mounted to the support means 40 in substantially flush relationship to th~ same's top surface 58. To this end, the support means 40 has formed in the ~0 top surface 158 thereof rear transverse and longitudinal channels 160, 162. The transverse channel 160 is positioned rearwardly of the front transverse channel 120 associated with the bridle 88.
The adjustment rod 164 is rotatably received within the support means rear transverse channel 160 at an inner end 172 of the rod, the rod outer end 174 extending laterally outwardly from the support means 40 at chair lateral side 176 opposite the height adjustment lever 50. The rod 164 is mounted in rotatable registry with the transverse channel 160 by brackets 178 secured to the support means 40 by any suitable mechanical means, such as by screws 180 in registry with aligned holes (not shown) in the brackets and threaded bores (not shown) in the support means.
The scissor mechanism 144 comprises a block 166, a pair of plates L !~ ~J) ~j ~
168 and a pair of arms 170. The block 166 is slidably received within the longitudinal channel 162 of the support means 40 and includes a pair of shoes 182 in which the tangs 152 of the cradle 142 are securely received. The plates 168 include threaded portions (not shown) operatively engaging the threaded ad~ustment rod 164. Because the plate threaded portions (not shown) and their respective rod threaded portions 184, 186 are oppositely directed, rotation of the adjustment rod in one direction or the other causes the plates to move toward or away from each other.
The arms 170 are pivotally mounted at front and rear ends 188, 190 thereof to and between the plates 168 and the block 166, respectively.
In this manner, when ths adjustment rod 164 is rotated in one direction, the plates 168 move toward each other causil~
the scissor arms 170 to pivot and force the block 166 toward the rear position of the tension control means 20. Rearward movement of the block 166 forces the cradle 142 and leaf spring 128 rearwardly, thereby decreasing the effective moment arm length between the spring and the force exerted by the occupant on the rear portion of the seat support upper leg 68 to increase the spring's resistance to deflection of the seat-and-back support 16. When the rod 164 is rotated in the opposite direction, the plates 168 move away from each other causing the scissor arms 170 to pivot and force the block 166 forwardly. Forward movement of the block 166 forces the cradle 142 and spring 128 forwardly, thereby increasing the effective moment arm length and thereby decreasing the spring's resistance to deflection of the seat-and-back support 16.
To facilitate manual rotation of the adjustment rod 164, the same is provided on the outer end 174 thereof with a hand knob 194. The hand knob 194 preferably differs in geometry from the height adjustment knob 60 so that the knobs can be easily differentiated by an occupant.
As indicated above, certain elements of the tension control means 20 are enclosed by the seat support lower leg cover 76 and are thus protected from damage and accumulation of dust which can affect operation of the tension control means.
In a second embodiment of the invention, illustrated in Figures 12 and 15, the tension control means 20 further comprises a retainer 196 securely mounted to the seat support lower leg 70 and having an open rear portion 198 providing access to the interior of the retainer. The retainer 196 can be formed 2 ~
integrally with the seat support lower leg 70 or be separate therefrom but mounted to the seat support by any suitable mechanical means. The stiffening means 18 comprises a substantially S-shaped leaf spring 200 having an upper curved end 201 freely engaging the seat support upper leg rear part at an apex 202 of the curved end, and a lower substantially straight end 204 received within the retainer 196 through the open rear portion 198 thereof. In this embodiment of the invention, the elements of the tension control means 20 are substantially identical to those of the above-described embodiment except that in the embodiment of Figure 12, a fulcrum pad 206 is mounted to the block 166 rather than the cradle 142. Like the cradle 142, however, the fulcrum pad 206 is set in slidable registry with the elongated opening 140 of the seat support lower leg 70 and includes tangs 152 engaging the shoes 182 of the block 166. The.
pad 206 is set in slidable engagement with a bottom sur.face 208 of the leaf spring straight end 204. In addition, like the cradle 142, the fulcrum pad 206 is adapted to move between the front and rear positions heretofore described to alter the effective length of the leaf spring and-thereby adjust the same's resistance to deflection of the seat-and-back support 16.
SpecificalIy, upon rotation of the adjustment rod 164 in one direction, the fulcrum pad 206 moves rearwardly to shorten the effective moment arm length between the spring and occupant downward force and thereby increase the spring's resistance to relative downward movement of the seat support upper leg 68.
When the fulcrum pad 206 is moved toward the front position of the tension control means, the moment arm is increased, thereby decreasing the springls resistance to downward relative movement of the seat support upper leg 6~. Consequently, when a relatively light occupant uses the chair, the fulcrum pad 206 is positioned adjacent the front position of the tension control means 20. Alternatively, when a heavy occupant uses the chair 10, the fulcrum pad 206 is positioned closer to the rear posi-tion of the~ tension control means 20.
In a third embodiment of the invention, illustrated inFigure 13, the stiffening means 20 comprises a substantially straight leaf spring 210 having the lower front end 212 thereof fixedly secured to the seat support lower leg front part 21~ by any suitable mechanical means, such as by a plurality of bolts 216 in registry with an equal number of pairs of aligned holes (not shown) extending through the spring front end 212 and the ?, .~ ~
lo~er leg front part 214. An upper rear end 220 of the leaf spring 210 is bent along a gradual curve, the apex 222 of which freely mattingly engages the seat support upper leg rear part 138.
In the tension control means 20 of the embodiment illustrated in Figure 13 the engaging means 123 comprises a cam pad 224 mounted about a horizontal axis of rotation on a pin 226 forming the mounting means 125 and rotatably secured transversely to and between opposing sidewalls 78 of the seat support lower leg cover 76. The cam pad 224 is set in registry with an enlarged opening 228 extending throuyh the seat support lower leg 70 and an enlarged channel 229 within and the support means 40.
The cam pad 224 engages a bottom surface 230 of the leaf spring 210 at a rear part 232 of the pad. The cam pad 224 is somewhat triangular in shape, with the rear end 232 thereof being enlarged relative to a front end 234 of the pad. Due to this geometry, rotation of the same in one direction causes the pad to move rearwardly and upwardly and to engage the spring lower front portion 212 to a greater extent to thereby shorten the effective moment arm length between the spring and the force exerted on the seat by the occupant and thereby increase the spring's resistance to deflection of the seat support upper leg 68. Rotation of the pad 224 in the other direction moves the same forwardly and downwardly to thereby increase the moment arm length and reduce the spring's resistence to deflection.
The actuating means 127 comprises an adjustment shaft 26 threada~ly mounted to the support means 40 through a vertical threaded bore (not shown) of the same, and has a lower end 238 extending downwardly from the support means and mounting a handwheel 240 and an upper end 242 above the casting and in abutting engagement with the cam pad rear end 232.
In operation, rotation of the handwheel 240 in one direction threads the adjustment shaft 236 upwardly to force the cam pad 224 about its pivot axis and rearwardly and upwardly against the leaf spring lower front end 212. The effective length of the leaf spring 210 is thereby decreased to therefore increase the spring's resistance to deflection of the seat support upper leg 68. Conversely, upon rotation of the handwheel 240 in the other direction, the shaft 236 is adjusted downwardly to lower the rear portion 232 of the cam pad 224 to thereby increase the effective length of the spring 210 and decrease the same's resistance to deflection of the upper leg 68.
?~
Referring now to Figures 1-3 and 7, the chair seat 72 comprises an inner shell (not shown) and an outer structural shell (not shown) and is mounted to and above the seat support upper leg 68 by any suitable mechanical means, such as by a plurality of screws (not shown) in registry with aligned holes 246 extending through the seat outer shell and the seat support upper leg. The shape of the seat 72 is complementary to that of the seat support 62, but enlarged with respect thereto to provide the necessary comfort and support to the occupant. In addition, the seat front portion 248 is rolled over to comfortably accommodate an occupant's legs. A cushion 250 is molded to the top of the inner shell. The inner shell is removably fastened by any suitable snap means to the outer shell. By this me~hod, the seat cushion 250 can be replaced as necessary. The seat 72 is preferably made of Zytel or polypropylene, compositions which provide some degree of flexibility to the seat during flex of the seat-and-back support 16.
As illustrated in Figures 1-3 the chair back 74 is substantially half oval in shape and has an enlarged U-shaped channel 252 within a central relief portion 254 formed on a rear surface 256 of the back. The back 74 comprises an inner and an outer shell (not shown), the outer shell being securely fastened to the back support 66, with the same received within the chan nel 252 and flush with respect to the relief portion 254 by any suitable mechanical means, such as by a plurality of screws (not shown) extending through aligned orifices (not shown) in the back and the back support. Like the chair seat 72, the back 74 is preferably made of a material such as Zytel or polypropylene to provide flexibility of the back. The chair back 74 is enlarged with respect to the back support and in this manner functions to distribute the weight transferred from the occupant to the chair seat and back support as the occupant leans rearwardly in the same between the upright and full tilt positions. A cushion 262 is molded to the inner shell, the same being removably fastened by any suitable snap means to the outer shell. By this method, the back cushion 262 can be replaced as necessary.
As illustrated in Figures 1-3, the chair can be provided with a pair of op~ional armrests 264 mounted on opposite lateral sides 56, 176 of the chair 10. Specifically, each armrest 264 is a substantially V-shaped flexible member having, with reference to the work intensive position of the seat-and-back support 16, a substantially horizontal leg 266 and a diagonal leg 26~, free 1 f '.~
ends of the horizontal and diagonal legs being ro-tatably mounted to the back 74 and the seat 72, respectively, at a lateral side 56 or 176 of the chair. The horizontal leg 266 provides support for an occupant's arm. In this manner, as the seat-and-back support 16 flexes downwardly and backwardly in response to a shift in an occupant's weight, the armrests 264 likewise flex thereby accommodating the changing geometry of the seat-and-back support. Flex of the V-shaped armrests generally occurs at the vertices 270 of the Vs, due to the rotatable connection be-tween the armrests and the seat 72 and back 74. Each armrest 264 is substantially rectangular, in cross section, with the thickness thereo~ tapering substantially at the vertex 270 of the V. A
reduction of thickness at the vertex facilitates the resiliency of the armrest 264.
As stated above, the armrests 264 are rotatably mounted to the chair back 74 and the chair seat 72 at lateral sides 56, 176 of the chair 10. To this end, the free ends 272, 274 of the horizontal and diagonal legs 266, 268, respectively, have formed thereon sockets 276. In addition, an attachment means 278 is provided for mounting the armrests 264 to the seat 72 and the back 74.
As best seen in Figure 14, the armrest attachment means 278 comprises a pair of U-shaped brackets 280, each having a web portion 282 and a pair of side portions 28~. Each side portion 284 includes a hole 286 extending therethrough. One bracket 280 is securely mounted to and between the chair back shells, with the web portion 282 sandwiched therebetween and the side portions 284 extending rearwardly of the chair. A recess in the inner chair back shell (not shown~ accommodates the bracket web. The other bracket 280 is mounted to and between the chair seat shells, the web portion 282 sandwiched therebetween and the side portions 284 extending downwardly from the chair seat 72. A
recess in the inner chair s at shell (not shown) accommodates the bracket web.
The attachment means 278 further comprises a hollow tubular spacer 288 partially received within each armrest socket 276, the spacer being aligned with a respective hole 286 in the U--shaped bracket 280. Bolts 290 extend through the aligned sockets 276, spacers 288 and holes 286 to securely mount the armrest 264 to the brackets 280. Hemispherical protective caps 292 can be placed over the bolts 290.
As stated above, the chair 10 comprises the first 2~ 7~
stabilizer means or bridle 88 pivotally mounted to and between the upper and lower leg portions 68, 70 of the seat support 62 for providing stability to the same during deflection of the upper leg 68 relative to the lower leg by virtue of the resilient first bight portion 69 intermediate the same.
In a similar manner, the armrests 264 also function as stabilizer means for the seat and back support 16, but not with respect to the upper and lower legs 68, 70 thereof. Rather, by virtue of the pivotal connection of the armrests 264 to and between the seat 70 and the back 74, on opposite lateral sides 56, 76 of the chair, the armrests provide lateral stability to the seat and back support 16 between the upper leg portion 68 and the upper back support portion 75 during relative deflection thereof by virtue of the resilient second bight portion 73.
While the invention has been described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. To the contrary, I intend to cover all alternative modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
Claims (21)
1. A chair comprising a seat, a back, a base and an elongated one-piece seat and back support having a substantially U-shaped seat support and a back support, said seat support including a lower leg portion supported by said base, an upper leg portion supporting said seat and a first bight portion intermediate said upper and lower leg portions, said back support having a second bight portion extending rearwardly and upwardly from said upper leg portion and a back support portion extending upwardly from said second bight portion, said first and second bight portions being resilient thereby enabling said upper leg portion and said back support portion to deflect downwardly and downwardly and rearwardly, respectively, in response to forces exerted on said upper leg portion and said back support portion, the maximum width of said upper leg portion being enlarged relative to the maximum width of said second bight portion to provide a relatively broad base of support for said seat against lateral movement thereof and to facilitate relative deflection of said second bight portion.
2. A chair according to claim 1, wherein the maximum width of said upper leg portion is equal to at least twice the maximum width of said second bight portion.
3. A chair according to claim 2, wherein the maximum width of said upper leg portion is approximately 10 inches and the maximum width of said second bight portion is approximately 4 inches.
4. A chair according to claim 2, wherein said seat and back support is formed of a glass reinforced nylon.
5. A chair according to claim 2, wherein said seat and back support is constructed of a glass reinforced polyester.
6. In a chair according to claim 2, and further comprising first stabilizer means connected to and between said upper leg portion and said back support portion for providing lateral stability to said back support during relative deflection of said back support portion.
7. A chair according to claim 6, wherein said stabilizer comprises elongated substantially V-shaped armrests mounted to and between said seat and said back on opposite lateral sides of said chair, each of said armrests being flexible along a portion thereof to accommodate relative deflection of said upper leg portion and said back support.
8. A chair according to claim 7, wherein each of said V-shaped armrests comprises substantially horizontal and diagonal legs rigid along substantially the full lengths thereof and a vertex portion intermediate said legs, said horizontal leg adapted to support an occupant's arm, said horizontal and diagonal legs being rotatably mounted at free ends thereof to said seat and back, respectively, and said vertex being flexible to accommodate relative deflection of said upper leg portion and said back support.
9. A chair according to claim 2, wherein said chair further comprises second stabilizer means mounted between said lower and upper leg portions for providing lateral stability to said seat support during relative deflection of said upper leg portion.
10. A chair according to claim 9, wherein said chair -further comprises support means mounted on said base and securely supporting said seat and back support at said lower leg portion thereof;
said lower leg portion comprises slot means extending therethrough; and said second stabilizer means is pivotally connected at an upper end thereof to said upper leg portion and at a lower end of said second stabilizer means to said support means through said slot means, said pivotal connections accommodating deflection of said upper leg portion relative to said lower leg portion.
said lower leg portion comprises slot means extending therethrough; and said second stabilizer means is pivotally connected at an upper end thereof to said upper leg portion and at a lower end of said second stabilizer means to said support means through said slot means, said pivotal connections accommodating deflection of said upper leg portion relative to said lower leg portion.
11. A chair according to clam 8, wherein said support means comprises a front transverse channel formed therein, said slot means comprising a pair of spaced elongated first slots extending through said lower leg portion, said upper leg portion comprising a pair of spaced second slots extending therethrough, said stabilizer means comprising:
an upper bracket positioned above and engaging said upper leg portion and having a pair of downwardly-depending flanges in registry with said spaced second slots, each of said flanges having a third slot extending upwardly from a base thereof forming a pair of spaced legs with a pair of aligned first holes extending therethrough;
a substantially U-shaped bracket comprising a pair of arms and a bight portion intermediate said arms, said bight portion being in rotatable registry with said front transverse channel in sandwiched relationship between said support means and said lower leg portion, said arms being in registry with said first slots at lower ends of said arms and in registry with said third slots at upper ends of said arms and having a pair of second holes extending through said upper ends and aligned with said third slots; and a pair of first pins in registry with said aligned first and second holes to pivotally connect said U-shaped bracket to said upper leg portion;
whereby movement of said upper leg portion relative to said lower leg portion causes said arms to pivot relative to said upper leg portion, said arms to register with said first slots to one of a greater and lesser extent and said bight portion to rotate relative to said lower leg portion to accommodate relative movement of said upper leg portion.
an upper bracket positioned above and engaging said upper leg portion and having a pair of downwardly-depending flanges in registry with said spaced second slots, each of said flanges having a third slot extending upwardly from a base thereof forming a pair of spaced legs with a pair of aligned first holes extending therethrough;
a substantially U-shaped bracket comprising a pair of arms and a bight portion intermediate said arms, said bight portion being in rotatable registry with said front transverse channel in sandwiched relationship between said support means and said lower leg portion, said arms being in registry with said first slots at lower ends of said arms and in registry with said third slots at upper ends of said arms and having a pair of second holes extending through said upper ends and aligned with said third slots; and a pair of first pins in registry with said aligned first and second holes to pivotally connect said U-shaped bracket to said upper leg portion;
whereby movement of said upper leg portion relative to said lower leg portion causes said arms to pivot relative to said upper leg portion, said arms to register with said first slots to one of a greater and lesser extent and said bight portion to rotate relative to said lower leg portion to accommodate relative movement of said upper leg portion.
12. A chair comprising a seat, a back, a base and an elongated one-piece seat and back support having a seat support portion, a back support portion and a bight portion intermediate said seat support portion and said back support portion, said bight portion being resilient thereby enabling said back support portion to deflect downwardly and rearwardly relative to said seat support portion in response to forces exerted on said back support portion, said chair further comprising stabilizer means connected to and between said seat support portion and said back support portion for providing lateral stability to said back support portion during relative deflection thereof.
13. A chair according to claim 12, wherein said stabilizer means comprises elongated V-shaped armrests mounted to and between said seat and said back on opposite lateral sides of said chair, each of said armrests being flexible along a portion thereof to accommodate relative deflection of said back support portion.
14. A chair according to claim 13, wherein each of said V-shaped armrests comprises substantially horizontal and diagonal legs rigid along substantially the full lengths thereof and a vertex portion intermediate said legs, said horizontal leg being adapted to support an occupant's arm, said horizontal and diagonal legs being rotatably mounted at free ends thereof to said seat and said back, respectively, and said vertex portion being flexible to accommodate relative deflection of said back support portion.
15. A chair according to claim 12, wherein said seat and back support is constructed of glass reinforced polyester.
16. A chair comprising a seat, a back, a base and an elongated one-piece seat and back support having a substantially U-shaped seat support and a back support, said seat support including a lower leg portion supported by said base, an upper leg portion supporting said seat and a first bight portion intermediate said upper and lower leg portions, said back support having a second bight portion extending rearwardly and upwardly from said upper leg portion and a back support portion extending upwardly from said second bight portion, said first and second bight portions being resilient thereby enabling said upper leg portion and said back support portion to deflect downwardly and downwardly and rearwardly, respectively, in response to forces exerted on said upper leg portion and said back support portion, said chair further comprising first stabilizer means connected to and between said upper leg portion and said back support portion for providing lateral stability to said back support during relative deflection of said back support portion.
17. A chair according to claim 16, wherein said first stabilizer means comprises elongated V-shaped armrests mounted to and between said seat and said back on opposite lateral sides of said chair, each of said armrests being flexible along a portion thereof to accommodate relative deflection of said upper leg portion and said back support.
18. A chair according to claim 17, wherein each of said V-shaped armrests comprises substantially horizontal and diagonal legs rigid along substantially the full lengths thereof and a vertex portion intermediate said legs, said horizontal leg being adapted to support an occupant's arm, said horizontal and diagonal legs being rotatably mounted at free ends thereof to said seat and back, respectively, said vertex portion being flexible to accommodate relative deflection of said upper leg portion and said back support portion.
19. A chair according to claim 18, wherein said chair further comprises second stabilizer means mounted between said lower and upper leg portions for providing lateral stability to said seat support during relative deflection of said upper leg portion.
20. A chair according to claim 19, wherein said chair further comprises support means mounted on said base and securely supporting said seat and back support at said lower leg portion thereof;
said lower leg portion comprises slot means extending therethrough; and said second stabilizer means is pivotally connected at an upper end thereof to said upper leg portion and at a lower end of said stabilizer means to said support means through said slot means, said pivotal connections accommodating deflection of said upper leg portion relative to said lower leg portion.
said lower leg portion comprises slot means extending therethrough; and said second stabilizer means is pivotally connected at an upper end thereof to said upper leg portion and at a lower end of said stabilizer means to said support means through said slot means, said pivotal connections accommodating deflection of said upper leg portion relative to said lower leg portion.
21. A chair according to claim 20, wherein said support means comprises a front transverse channel formed therein, said slot means comprising a pair of spaced elongated first slots extending through said lower leg portion, said upper leg portion comprising a pair of spaced second slots extending therethrough and said stabilizer means comprising:
an upper bracket positioned above and engaging said upper leg portion and having a pair of downwardly-depending flanges in registry with said spaced second slots, each of said flanges having a third slot extending upwardly from a base thereof forming a pair of spaced legs with a pair of aligned first holes extending therethrough;
a substantially U-shaped bracket comprising a pair of arms and a bight portion intermediate said arms, said bight portion being in rotatable registry with said front transverse channel in sandwiched relationship between said support means and said lower leg portion, and said arms being in registry with said first slots at lower ends of said arms and in registry with said third slots at upper ends of said arms and having a pair of second holes extending through said upper ends and aligned with said third slots; and a pair of first pins in registry with said aligned first and second holes to pivotally connect said U-shaped bracket to said upper leg portion;
whereby movement of said upper leg portion relative to said lower leg portion causes said arms to pivot relative to said upper leg portion, said arms to register with said first slots to one of a greater and lesser extent and said bight portion to rotate relative to said lower leg portion to accommodate relative movement of said upper leg portion.
an upper bracket positioned above and engaging said upper leg portion and having a pair of downwardly-depending flanges in registry with said spaced second slots, each of said flanges having a third slot extending upwardly from a base thereof forming a pair of spaced legs with a pair of aligned first holes extending therethrough;
a substantially U-shaped bracket comprising a pair of arms and a bight portion intermediate said arms, said bight portion being in rotatable registry with said front transverse channel in sandwiched relationship between said support means and said lower leg portion, and said arms being in registry with said first slots at lower ends of said arms and in registry with said third slots at upper ends of said arms and having a pair of second holes extending through said upper ends and aligned with said third slots; and a pair of first pins in registry with said aligned first and second holes to pivotally connect said U-shaped bracket to said upper leg portion;
whereby movement of said upper leg portion relative to said lower leg portion causes said arms to pivot relative to said upper leg portion, said arms to register with said first slots to one of a greater and lesser extent and said bight portion to rotate relative to said lower leg portion to accommodate relative movement of said upper leg portion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US454,351 | 1982-12-29 | ||
| US45435189A | 1989-12-21 | 1989-12-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2017208A1 true CA2017208A1 (en) | 1991-06-21 |
Family
ID=23804268
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2017208 Abandoned CA2017208A1 (en) | 1989-12-21 | 1990-05-18 | Chair |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2017208A1 (en) |
-
1990
- 1990-05-18 CA CA 2017208 patent/CA2017208A1/en not_active Abandoned
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| Date | Code | Title | Description |
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| FZDE | Dead |