Patent Publication Number: US-8540314-B2

Title: Flex chair

Description:
CLAIM OF PRIORITY 
     This application claims priority to U.S. Ser. No. 61/280,016 filed on Oct. 28, 2009, the contents of which are fully incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to furniture, in particular, to a chair with a flexible support structure. 
     BACKGROUND OF THE INVENTION 
     The muscles of the human body tend to get tired when one is sitting in an uncomfortable position or in the same position for long periods of time. Humans sit most while working and discomfort is most noticeable during tasks requiring creativity or concentration. For this reason commercial and home office furniture usually includes multiple points of adjustment. Additionally, such furniture may have cushioning so as to lessen the reciprocal pressure that a supporting surface of a chair exerts on a sitter&#39;s body. Such chairs are generally able to rise and sink, lean back and swivel. Some, especially the more costly examples have adjustable armrests, lumbar supports, massagers and extra layers of cushioning. 
     DESCRIPTION OF THE RELATED ART 
     The relevant prior art involving adjustable chairs includes: 
     U.S. Pat. No. 5,921,628 issued on Jul. 13, 1999 that describes a “Pendulating Stool” that has a seat portion (1), an intermediate portion (13) and a base portion (2), wherein the intermediate portion (3) is mounted tiltably and returnably on the base portion (2). The intermediate portion (3) comprises a central pillar (4) and a spring structure (5). The central pillar (4) and the spring structure (5) are connected in series in the flow of force of the seat weight between the seat portion (1) and the base portion (2) and a bearing guide is provided between the central pillar (4) and the spring structure (5). 
     U.S. Pat. No. 4,932,719 issued to Gonzalez y. Rojas on Jun. 12, 1990 for an “Inclinable stool” that describes an inclinable stool for supporting the weight of the body and permitting a variety of inclined positions comprises a tripod base, supporting a vertically extending spring hinge assembly, a support column mounted on the spring hinge assembly and inclinable relative thereto, and a seat assembly disposed on the support column. A pair of spaced, stabilizing members, slidably and pivotally mounted to the support column, rotate with the seat assembly and support column, thereby supporting the seated user against backwardly directed inclinations while allowing forward and lateral inclinations, regardless of the rotated position of the seat. 
     U.S. Pat. No. 5,556,170 issued to Lai, et al. on Sep. 17, 1996 entitled “Sleeve structure of an office chair” that describes a sleeve structure of an office chair fitted around a pneumatic bar. The sleeve structure includes a sleeve body and a steel circular tube. The sleeve body is a plastic hollow flexible member, having a sleeve hole and two annular stoppers at two ends. Multiple (preferably 8 to 12) equally spaced axial ribs are arranged on the outer surface of the sleeve body and three equally spaced axial slits are formed on the sleeve body. Two polygonal (preferably hexagonal, heptagonal or octagonal) plastic fitting members are fitted in two ends of the steel circular tube to form an assembly. Each fitting member has an annular stopper at an end thereof. The assembly of the steel circular tube and the fitting members is forcedly fitted into the sleeve hole of the sleeve body by a machine and locked by the stoppers of the sleeve body. In turn the pneumatic bar is fitted into the steel circular tube with the angles of the fitting members tightly contacting with the pneumatic bar nearly without clearance existing there between. Then the sleeve body is fitted into a bar seat tube to form a support stem of the office chair. When the pneumatic bar suffers a load or a torque by different inclined angles, the office chair is always stably and safely supported by the support stem without swinging to keep a user comfortable. 
     U.S. Pat. No. 6,386,635 issued to Ralph on May 14, 2002 entitled “Shock absorbing boat seat assembly” that describes a shock absorbing boat seat assembly for providing a more comfortable ride upon a boat moving upon water. The shock absorbing boat seat assembly includes one or more seat members each having a seat and a backrest connected to the seat; and also includes one or more base assemblies for supporting one or more seat members with each of one or more base assemblies having a base member being adapted to securely mount upon a deck of a boat, and also having a boss-like support member securely disposed upon the base member and having a opening therein, and further having a hollow tubular member being movably disposed in the opening of the boss-like support member, and also having a shock absorbing assembly for absorbing shock, and further having a seat support member securely mounted upon the tube. 
     However, prior inventions suffer from drawbacks that the present device aims to redress. For example, the prior art devices are generally only able to lean back or stay upright. A user, who wishes to lean forward or to the side, will be required to shift into a less supportive and possibly less comfortable sitting posture. This is a significant drawback since the majority of tasks require some degree of reaching forward or to the side. This diminishes the effectiveness of comfort features since it forces people to lean away from comfort features provided by prior art chairs. The present invention resolves this drawback by providing a multidirectional leaning ability. A person need not alter his or her sitting position or posture to engage in such common tasks as leaning forward to look at a computer screen, leaning back while speaking on the phone, or leaning sideways to answer a phone call, communicate with a neighbor or to gaze out the window. 
     As an added convenience item, the present invention is capable to a limited automatic height adjustment without resorting the use of cranks, pneumatics or height adjustment pins, which are nonetheless included to provide additional height adjustment. This feature is based on the fact that a taller person will generally weigh more than a shorter person. The extra weight may cause a greater degree of contraction of the resilient component when exposed to the weight of a tall person rather than a short person. Thus a taller person may sit at a substantially equal level as a shorter person. 
     The present invention also provides a user with an ability to exercise torso muscles and lower limbs. One may take advantage of this feature by running a series of squatting or rocking exercises. The resilient component would then serve a dual role of a shock absorber and a tension element. 
     Various implements are known in the art, but fail to address all the problems solved by the invention described herein. One embodiment of this invention is illustrated in the accompanying drawings and will be described in more detail herein below. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a chair having a seat, a first support base and an upright elongated support element. The upright elongated support element has a first point and a second point, with the first point connecting to the seat and the second point connecting to the first support base. The first support base is bolstered by a resilient component since the resilient component is disposed beneath the first support base. The resilient component is capable of providing cushioning to the first support base, and is also capable of providing a full axial rotation to said upright elongated support element. 
     Therefore, the present invention succeeds in conferring the following, and other not mentioned, desirable and useful benefits and objectives. 
     It is an object of the present invention to provide supportive yet substantially cushioned seating equipment. 
     It is another object of the present invention to provide seating equipment that is capable of leaning in all directions without tipping over. 
     Yet another object of the present invention is to provide a device that is capable combining both the rotational and the cushioning capability in a single element. 
     Still another object of the present invention is to provide a device where a standard wheeled base of a commonly used office chair may be enhanced with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional side view of a preferred embodiment of the present invention. 
         FIGS. 2 and 3  are cross-sectional side views of alternative embodiments. 
         FIGS. 4A-4D  illustrate the novel utility of the present invention. 
         FIG. 5  is a side view of another preferred embodiment of the present invention. 
         FIG. 6  is an exploded diagram of the embodiment shown in  FIG. 5 . 
         FIGS. 7 and 8  are detailed views of a preferred embodiment of the resilient component. 
         FIG. 9  is another preferred embodiment of the present invention. 
         FIG. 10  is a view of the preferred embodiment shown in  FIG. 9 , without the outer shell. 
         FIGS. 11A-11C  are side views of the embodiment illustrated in  FIG. 9 . 
         FIG. 12  is a bottom view of the elongated upright support, a height adjustment lever, and the outer shell. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments of the present invention will now be described with reference to the drawings. Identical elements in the various figures are identified with the same reference numerals. 
     Reference will now be made in detail to embodiment of the present invention. Such embodiments are provided by way of explanation of the present invention, which is not intended to be limited thereto. In fact, those of ordinary skill in the art may appreciate upon reading the present specification and viewing the present drawings that various modifications and variations can be made thereto. 
     Referring now to  FIG. 1  shown is flex seat  10  having a seat  20 , a first support base  30  and an upright elongated support element  40 . The upright elongated support element  40  may have a first point  50  and a second point  60 . The flex seat  10  also has a resilient component  70  that may be enclosed in the first support base  30 . The first support base  30  may also have tension elements  80  that may be attached via fasteners  82 . The upright elongated support element  40  may include a first telescoping member  100 , a second telescoping member  110  and a tightening element  120 . The tightening element  120  may, for instance, included a set screw  140  and a pin  150 . The resilient component  70  may, for instance, include an elastic sphere  160 . 
     In a preferred embodiment, a distance  220  between the first base support and the seat may be adjustable by means of the first telescoping member  100  and the second telescoping member  110 . A distance  210  between the first support base  30  and a second support base  230  may vary dependant on a loading of the resilient component  70 . 
     The seat  20 , may be round or square or in any other shape. The seat preferably contains a seat cushion filling  24  that may be a cushioning material, such as, but not limited to synthetic and natural elastomers, such as a natural rubber, silicone rubber, poly-isoprene, or polystyrene or springs. Alternatively, the seat cushion filling  24  may be a jell-like substance, which may be an elastomer as well, or a liquid that is hermetically sealed. The seat  20  may additionally include a back portion or a back rest, with or without armrests (not shown). The upholstery for the seat&#39;s outer surface  22  may be any material commonly used in the art, such as, but not limited to vinyl, leather or plastic. The seat  20  may be able to axially rotate 90 about the axis of the upright elongated support element  40  or these components may be screwed-on, glued, welded, soldered, cramped or fastened together. 
     The seat  20  may be supported by an upright elongated support element  40 , which may have one or more sections for height adjustment. The upright elongated support element  40  (support element) may preferably be manufactured out of metal or metal alloy, but may also be made out of polymer or wood. Additionally the support element  40  may preferably be hollow and substantially tubular. Individual sections of a multi-sectioned upright elongated support element are capable of sliding in and out of each other. These sections may be made up of a first telescoping support member  100  and a second telescoping support member  110  that may slide or telescope within each other. A tightening element  120  may be used to secure first and second telescoping supports  100  and  110  at a desirable length. The tightening element  120  may be a set screw  140 , a locking pin  150 , O-clamp (not shown) or a threaded connection (not shown). A tightening knob, a lever, a pull handle, or a crank handle may be included. The first and second telescoping support member may also slide within each other using a gas cylinder, such as shown in  FIG. 10 . The first end  50  connects to the seat  20  while the second end  60  connects to the first support base  30 . 
     The seat  20  may contain a socket  55  ( FIG. 5 ) into which a first point  50  may be inserted. Alternatively a first point  50  may contain a flat perpendicular flange (not shown) having openings for fasteners that would secure the seat  20 . The seat  20  preferably has a seat cushion filling  24  and a seat&#39;s outer surface  22 . 
     The upright elongated support member  40  is supported by a first support base  30 . The first support base  30  is preferably supported by a resilient component  70 . The resilient component  70  is shown as being a sphere  160 . A second support base  230  may be provided for stability of the article  10 . Tension elements  80  ensure that the first support base  30  will not shift or slide off of the resilient component  70 . The tension elements  80  are secured to the first support base  30  and to the second support  230  with fasteners  82 . The tension elements  80  may extend and contract independently of each other. The tension elements  80  may be made be elastomeric or rubberized elastics or metallic springs. The tension force of the tension elements  80  is always kept at some positive value by the expansion or outward pressure of the resilient component  70 . It follows that the resilient component  70  is preferably always slightly compressed due to the force exerted by the tension elements  80 , while the tension elements are always slightly stretched due to the force of the resilient component. 
     The flex seat  10  is preferably swiveling, meaning that the seat  22  may rotate around the y axis as shown by the arrow  90 . Swiveling is usually achieved by an upright axle surrounded by a washer or a ball bearing wheel (not shown). Components needed to accomplish the swiveling feature may be within the first point  50 , the second point  60 , or may be disposed within the resilient component  70 . In the latter embodiment, the second point  60  would traverse the width of the first support base  30  and terminate in the swiveling mechanism disposed within the resilient element  70 . The first support base  30  may be a round disc or may be embodied in any other shape. The first support base  30  affixes to the second point  60  of the upright elongated support element. The first support base  30  is preferably planar, but may be concave or convex as aesthetically or functionally desired. 
     Still referring to  FIG. 1 , the first support base  30  is shown supported by the resilient component  70 . The resilient component  70  is preferably spherical  160  or may be embodied in any other shape such as a cylinder or a cube. The resilient component  70  may also a conventional metal or iron spring  170 , as shown in  FIGS. 5-8 . Preferably, the resilient support  70  may be somewhat narrower than the width of the first support base. The preferred width or diameter  37  of the first support base  30  may be between 1 and 2.5 feet. 
     The resilient component  70  may be a rubber ball, or may be made from a flexible gel-like material, such as a silicone gel or styrene-ethylene/butylene-styrene (SEBS OR SEPS) or a thermoplastic elastomer (TPE), it may also be made from a natural or synthetic rubbers. The resilient component  70  is preferably centered beneath the first support base  30  and beneath the upright elongated support element  40 . When subjected to pressure, the resilient component  70  is capable of compressing and deforming for extended periods of time. When pressure is removed, the resilient component  70  is able to assume its original form, without any memory of prior deformation. 
     A second support base  230  may be provided as well. The second support base  230  rests on a supporting surface such as a floor. The second support base  230  may be wider than the first support base  30  or may have the same shape and dimensions. It is preferable that the second support base  230  may be substantially flat so that it provides for a maximum support for the present invention. The outer edges of the first support base  30  and the second support base  230  may function as a positive stop point for maximum angle of deflection of the first support base  30 . Meaning, the second support base  230  may prevent the present invention from toppling to the ground, when exposed to angled pressure  250  ( FIGS. 4C ,  4 D). The second support base  230  may additionally contain legs, or wheels (not shown). 
     It is highly preferable to sandwich the resilient component  70  between the first support base  30  and the second support base  230 . The two support bases may be tied together with a plurality of evenly spaced tension bands  80 . The tension bands  80  may be elastic bands or extension springs. In such an embodiment, the base  210  is especially stable, because the resilient component  70 , which is biased toward an outward expansion, is held under constant tension by the tension bands  80 , which are biased towards contraction. The constant expansion force exerted by the resilient component  70  also serves to keep the tension bands  80  under a content tension. 
     The various parts of the present invention may be made from any material, including but not limited to: plastics and resins including but not limited to plastic, rubber, foam, silicone, ABS, Polycarbonate, Noryl™, PVC, Polystyrene, ABS/PVC, PVC/Acrylic, Poly-sulfone, Acrylic, Polyethylene, Kydex™, PETG; glass, including but not limited to fiberglass, borosilicate, or quartz; wood; metals, including but not limited to iron, tin, aluminum, copper; rubber including but not limited to natural rubber, SBR, Isoprene rubber, Butadiene rubber, and Chloroprene rubber; or any combinations or composites of these materials or other materials and new materials that may be manufactured in the future. 
       FIGS. 2 and 3  illustrate several alternatives to the embodiment shown in  FIG. 1 . Shown is a flex seat  10  having a seat  20 , a first support base  30 , an upright elongated support element  40 , a resilient component  70  and a tension element  80 . The upright elongated support element  40  has a first telescoping member  100 , a second telescoping member  110  and a tightening element  120 . The flex seat  10  may also have a first support base  30  second support base  230 . The first support base  30  may be substantially flat or substantially convex, and may also be elliptical, square or rectangular, or any other shape. 
       FIGS. 2 and 3  illustrate how a conventional chair or stool may be easily converted into an embodiment of the present invention. The first support base  30  is shown in the shape of rays  400 . Such a base is well known in the art and is commonly present in a majority of office chairs and other commercial or residential furniture. Often the rays  400  may feature wheels  410 , which may remain in place after a conversion into an article  10  personifying the present invention. Such a first support base  30  may connect to the resilient component  70  with netting  85  or with tension bands  80 . Also, in a ray shaped first support base  30 , the rays may have special openings or hooks for tension elements  80  or for netting  85 . Alternatively, the tension elements  80  or the netting  85  may contain loops that can be slipped over the rays  400 . 
       FIGS. 4A-4D  illustrate the affects of different load angles on the present invention. 
       FIG. 4A  shows an unloaded flex seat  10  having a seat  20 , a first support base  30 , an upright elongated support element  40 , a resilient component  70 , tension elements  80  and a second support base  230 . 
       FIG. 4B  shows a flex seat  10  loaded with a centrally located, downward load  240 . When a centrally located, downward load  240  is exerted on the seat  20 , the first support base  30  may deform the resilient component  70  in a downward fashion. 
       FIGS. 4C and 4D  show a flex seat  10  loaded with an angled load  250 . Angular or partial deformation shown in  FIGS. 4C and 4D  is caused by the sideways leaning of the seat  20 , which exerts an angular force or pressure  250 . The deformation angle  254  may be equal to, greater then or less then, the deflection angle  252 . During the deflection, the tension elements  80  on the deflection side would contract, while those on the side opposite to the deflection would expand. This expansion and contraction eventually reaches a maximum limit, at which point the seat  20  will not lean any further. The maximum expansion limit is preferably reached before the toppling point of the article  10 . It is also highly preferable that the tension elements  80  and the resilient element  70  can withstand weights between 100 and 400 pounds. 
     The resilient component  70  may be inflatable and may provide a full axial swiveling capability  90  to the upright elongated support element  40 . The swivel capability may be embodied in a resilient support  70  turning by itself, or by encompassing a central rod (not shown). Such a rod may be affixed within the first support base  30  and inserted into the center of the resilient component  70 . The rod (not shown) would then swivel within the resilient component  70 , and may have the same or similar elasticity characteristics as the resilient component  70 . In another alternative, the upright elongated support element  40  may also swivel within the resilient component  70  without causing the resilient component  70  to rotate as well. This may be enabled if the upright elongated support element is encased in within a ball bearing gasket that may be present in a central rod or core of the resilient component  70 . Alternatively, the entire resilient component may rotate in the same axial plane as the upright support element  40 . The base  210  may additionally have exterior covering or upholstery (not shown). This covering may assist in holding the base  210  together or would be able to partially or completely conceal the resilient component  70 . 
       FIG. 5  illustrates another preferred embodiment of the present invention. Shown is a flex seat  10  having a seat  20 , a first support base  30  and an upright elongated support element  40 . The upright elongated support element  40  may have a first point  50 , a second point  60 . The flex seat  10  may also include a resilient component  70  that may, for instance, be a conventional metal or iron spring  170  and tension elements  80 . The upright elongated support element  40  may include a first telescoping member  100  and a second telescoping member  110 . 
     In this embodiment, the seat  20  may be mounted directly on the resilient component  70  or on a second support base  230 . The spring  170  may be the preferred embodiment of the resilient component  70  for the flex seat  10  as embodied in  FIG. 5 . The spring  170  may be mounted above the first support base  30 . The first point  50  of the upright elongated support element  40  is affixed within the socket  55  at the bottom of the first support base  30 . The second point  60  is mounted within the base  31 . The first telescoping member  100  and the second telescoping member  110  are used for adjusting the height  225  of the first support base  30  above the base  31 . The height  225  may vary between 1 and 3.5 feet, while distance  220  between the first base support and the seat vary between 2 and 6 inches between full compression and full extension respectively. The width  227  of the seat  20  may be between 0.75 and 1.5 feet, while the dimensions of the base  31  may be the same or slightly larger than that of the seat  20 . 
     The base  31  may contain the swiveling capability. Alternatively, the seat may be swiveling with respect to the second support base  230 . The functionality of the second support base  230  may be encompassed within the seat  20 . 
     The tension elements  80  may link said first support base  30  and the second support base  230 . Each tension element  80  may be capable of independent stretching or contracting. Independent extension and compression is necessary to support an angled load pressure on the seat  20  which may cause some tension elements  80  to contract and others to stretch. 
       FIG. 6  is an exploded diagram of the upper part of the preferred embodiment shown in  FIG. 5 . Shown in  FIG. 6  is a seat  20 , a first support base  30 , a resilient component  70 , and tension elements  80 . Also shown is a spring mounting protrusion  39 , tension element openings  38 , tension element caps  84 , and sockets  238 . The tension elements  80  are shown mounted within the sockets  232  of the second support base  230 , and within tension element openings  38 . The sockets  39  and openings  38  may contain adhesives or threading for fixating the tension elements  80 . In an alternative embodiment, the tension elements  80  may be replaced with rods that provide an oblique structural support for the resilient component  70 . Such tension elements  80  will be inflexible and function as shafts that slide up or down within the openings  38  as the spring  170  is compressed or released. 
     The resilient component  70  may be welded, crimped, frictionally attached, or attached with a screw thread to the mounting protrusion  39 . In an alternative embodiment, a tension element may be incorporated within the spring  170 . Such a tension element may be flexible or rigid. The second support base  230  functions as an upper mount point for the resilient component  70 , the tension elements  80 , and the seat  20 . Alternatively, the second support base  230  may be omitted, with the seat  20  functioning as the mount point. 
       FIGS. 7 and 8  provide a detailed view of the preferred embodiment shown in  FIG. 5 . Shown is a first support base  30  an upright elongated support element  40 , a resilient component  70 , tension elements  80 , and tension element caps  84 . The tension element caps  84  may be affixed to the tension elements  80  with threading, and are used to secure the tension elements  80  within the second support base  230 . Also shown are tension element openings  38  and sockets  238 . The sockets  238  may further contain lips  36  and  236  respectively. The lips  36  and  236  may provide an additional area for adhesives or threading. The lips  36  and  236  may also be used to retain a lubricant in an embodiment where the tension elements  80  are shafts. Preferably, there are three tension elements  80 . However, other embodiments may feature fewer or additional tension elements  80 . 
       FIG. 9  illustrates a third preferred embodiment of the present invention. A flex seat  10  may have a seat  20 , an upright elongated support element  40 , a base  31 , a second portion  280 , an adjustment lever  300 , an outer casing  310 , and a slit  320 . The seat  20  may swivel independently or together with the cylinder  270  ( FIG. 10 ). 
     An outer casing  310  or jacket surrounds the upright elongated support element  40 . The bottom rim  312  of the casing  310  may span all or part of the height of the elongated support element  40 . The casing  310  is preferably mounted on the seat  20  and moves up and down with it. A slit  320  may be provided to accommodate the adjustment lever  300 . The base  31  may have conventional leg rays  400  as are common in this class of furniture. The rays  400  may contain wheels  410  ( FIG. 2 ,  3 ). Alternatively, the embodiment shown may have a base  31  as described in, for instance, the descriptions of  FIG. 1  or  FIG. 8 . 
       FIG. 10  illustrates the embodiment shown in  FIG. 9 , without the external casing  310  or the adjustment lever  300 . Shown are a seat  20 , a spring  170 , a cylinder  270 , an exterior flange  272 , a second portion  280 , a first end  290  and a base  31 . In this embodiment the upright elongated support element  40  is preferably made from three sections. The first portion  260  is a top section that supports the seat  20 . The first portion  260  is slidably disposed within a cylinder  270 , meaning it telescopes into an out of the cylinder  270 . The cylinder  270  may be a gas or an oil cylinder or contain a combination of components. The cylinder  270  is capable of sliding up and down the second portion  280 ; meaning, it is in a slided association with the second portion  280 . This sliding is controlled with a lever  300  that activates a transfer of gas or oil from one chamber within the cylinder  270  to another, thus causing the cylinder  270  to slide up or down the second portion  280 . 
     Shown also is a flange  272  that may be present on the exterior surface of the cylinder  270 . The flange  272  supports the resilient component  70 , in this case, a spring  170 . The spring  170  affords extra cushioning and suppleness. Note, that in this embodiment, an angled load will not cause the seat  20  to compress at an angle, as in embodiments shown in  FIGS. 1 and 5 . Rather the compression and extension of the elongated support element  40  is limited to an up and down adjustment of the cylinder  270  and telescoping of the first portion  260 . 
       FIGS. 11A-11C  are a close up illustration of the cover. Shown are a seat  20 , a bottom face of the seat  29 , a casing mount area  27 , a swiveling section  21 , a casing  310 , an adjustment lever  300 , slit  320 , a second portion  280 , a spring  170 , and a base  210 . The swiveling section  21  may contain ball bearing within a gasket enabling the seat  20  to rotate about the casing  310 , or the first section  260  ( FIG. 10 ). Alternatively, both the seat  20  and the casing  310  swivel as a single unit. The casing  310  may be welded or attached with fasteners or adhesives to the bottom face  29  of the seat  20 . 
       FIG. 12  shows the bottom view of the seat  20 . Shown also is the cylinder  270  with a cylinder opening  272 . The cylinder opening is mounted on top of the second portion  280  ( FIG. 10 ). The lever  300  protrudes through a slit  320  and terminates inside the cylinder  270 . The lever  300  may have a pivot point  302  which may be spring loaded. The spring loaded pivot point  302  may ensure that the lever returns to a previous position after the seat  20  has been raised or lowered. 
     Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made only by way of illustration and that numerous changes in the details of construction and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.