Abstract:
A suspension system for a seat. The suspension system includes a first frame member, a second frame member connectable to the seat and movably coupled to the first frame member, a suspension member coupled to both the first frame member and the second frame member and suspending the second frame member above the first frame member, an adjustment mechanism coupled to the suspension member and manually manipulatable by an operator to adjust the stiffness of the suspension, a handle movable along a portion of the adjustment mechanism and facilitating manual manipulation of the adjustment mechanism, and an engaging member resiliently resisting movement of the handle under its own weight along the portion of the adjustment mechanism.

Description:
FIELD OF THE INVENTION 
   The present invention relates to suspension systems for seats and, more particularly, to suspension systems for seats that include suspension adjusting handles for adjusting the suspension of the seats. 
   BACKGROUND OF THE INVENTION 
   Suspension systems are used in a variety of vehicles, such as, cars, trucks, lawnmowers, construction equipment, all-terrain-vehicles (ATV&#39;s), etc., for the added comfort of the operators of such vehicles. Suspension systems can either be fixed or adjustable. Fixed suspension systems have a constant suspension with a fixed stiffness, while the stiffness of the suspension in adjustable suspension systems is adjustable. 
   SUMMARY OF THE INVENTION 
   In some aspects, the invention provides a suspension system for providing suspension to a seat on a vehicle. The suspension system includes a first frame member and a second frame member connectable to a seat and coupled to the first frame member. The second frame member is movable relative to the first frame member. The suspension system also includes a suspension member coupled to both the first frame member and the second frame member. The suspension member suspends the second frame member above the first frame member and resists movement of the second frame member relative to the first frame member. The suspension system further includes an adjustment mechanism coupled to the suspension member and manually manipulatable by an operator to adjust the stiffness of the suspension member and a handle to facilitate manual manipulation of the adjustment mechanism. The handle is movable along a portion of the adjustment mechanism between a first position and a second position. The suspension system also includes an engaging member resiliently resisting movement of the handle between the first position and the second position. 
   The suspension system may also include a threaded rod threadably coupled to the suspension member and rotatable to adjust the stiffness of the suspension and a handle coupled to the threaded rod to facilitate rotation of the threaded rod. The handle is slidable relative to the threaded rod. The engaging member may resiliently engage the threaded rod and resiliently resist sliding of the handle relative to the threaded rod. 
   The seat may pivot relative to the vehicle between a substantially horizontal position and a non-horizontal position. The above-described threaded rod may pivot with the seat between the substantially horizontal position and the non-horizontal position. The engaging member may resiliently engage the threaded rod to resiliently resist sliding of the handle, under the weight of the handle, along the threaded rod when the threaded rod is in the non-horizontal position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of a seat and a suspension system including a suspension adjusting handle embodying the present invention, shown in a substantially horizontal position. 
       FIG. 2  is a top perspective view of the suspension system and the suspension adjusting handle shown in  FIG. 1 . 
       FIG. 3  is a front view of the suspension system and the suspension adjusting handle shown in  FIG. 1 . 
       FIG. 4  is a side view of the seat, the suspension system and the suspension adjusting handle shown in  FIG. 1 , shown in a non-horizontal position. 
       FIG. 5  is an exploded perspective view of the suspension system and the suspension adjusting handle shown in  FIG. 1 . 
       FIG. 6  is a front perspective view of the suspension adjusting handle shown in  FIG. 1 . 
       FIG. 7  is a rear perspective view of the suspension adjusting handle shown in  FIG. 1 . 
       FIG. 8  is a cross-sectional view taken along line  8 — 8  in  FIG. 7 . 
   

   Before at least one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and variations thereof herein are used broadly and encompass direct and indirect connections and couplings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings. 
   DETAILED DESCRIPTION 
     FIGS. 1–5  illustrate a seat  20  and a suspension system  24 , which is connected between the seat  20  and a vehicle  28  (shown in phantom in  FIG. 4 ). Suspension systems are often characterized by their “stiffness,” which is a reference to the resistance of the seat to deflection due to a passenger sitting in the seat. The greater the resistance to deflection, the higher the stiffness of the seat. 
   The suspension system  24  includes an upper frame  32 , a front cam member  36 , a pair of rear cam members  40  and a lower frame  44 . The upper frame  32  is connected to the seat  20  in a variety of manners, such as, for example fastening, welding, integrally forming, or other permanent or non-permanent connections. The upper frame  32  is also connected to the front cam member  36  and the rear cam members  40 . 
   The front cam member  36  includes a rod  48  and a cam plate  52  positioned at each end of the rod  48 . Each cam plate  52  includes four corners and defines an aperture  56  therethrough near each corner. The ends of the rod  48  are positioned in one of the apertures  56  of each cam plate  52 . In the illustrated construction, the rod  48  is welded to the cam plates  52 . Alternatively, the rod  48  may be integrally formed with the cam plates  52 , fastened to the cam plates  52 , or connected to the cam plates  52  in other manners of permanent or non-permanent connections and still be within the spirit and scope of the present invention. 
   The rear cam members  40  are similar to the cam plates  52  of the front cam member  36 . Each rear cam member  40  includes four corners and defines an aperture  60  therethrough near each of the four corners. 
   The front cam member  36  is pivotally connected to the upper frame  32  by inserting a fastener  64  through one of the cam plate apertures  56  in each cam plate  52  and through upper frame apertures  68  defined in the upper frame  32 . The rear cam members  40  are pivotally connected to the upper frame  32  by inserting a fastener  72  through one of the rear cam apertures  60  in each rear cam member  40  and through upper frame apertures  68  defined through the upper frame  32 . The upper frame  32  is pivotal relative to the front and rear cam members  36 ,  40  about the fasteners  64 ,  72 . 
   The front and rear cam members  36 ,  40  are pivotally connected to the lower frame  44  in a manner similar to the manner in which they are connected to the upper frame  32 . To connect the front cam member  36  and the lower frame  44 , a fastener  76  is inserted through another of the cam plate apertures  56  of each cam plate  52  and through lower frame apertures  80 . To connect the rear cam members  40  to the lower frame  44 , a fastener  84  is inserted through another of the rear cam apertures  60  of each rear cam member  40  and through lower frame apertures  80 . The front and rear cam members  36 ,  40  are pivotal about the fasteners  76 ,  84  relative to the lower frame  44 . 
   In some constructions the lower frame  44  is rigidly connected to the vehicle  28 . In such constructions, the lower frame  44  may be rigidly connected to the vehicle  28  by using fasteners, welding, integrally forming, or other manners of rigidly connecting the lower frame  44  to the vehicle  28 , such that the lower frame  44  does not move relative to the vehicle  28 . In other constructions, the lower frame  44  may be pivotally or slidably connected to the vehicle  28  and allow the seat  20  to be pivoted or slid between a substantially horizontal position (see  FIG. 1 ) and a non-horizontal position (see  FIG. 4 ). In such embodiments, the lower frame  44  may include a pivot member  88  (see  FIG. 4 ) positioned at a front or a rear of the lower frame  44  to allow the seat  20  to pivot about a front or rear, respectively, of the lower frame  44 . 
   With continued reference to  FIGS. 1–5 , the suspension system  24  also includes a suspension assembly  92  for defining the stiffness of the suspension (e.g., establishing resistance to movement of the upper frame  32  down toward the lower frame  44  in response to an operator sitting in the seat and in response to dynamic forces arising during vehicle operation). The suspension assembly  92  includes a connecting member  96 , a pair of suspension members or extension springs  100  and a suspension carriage  104 . The connecting member  96  includes a pair of upturned flanges  108 , four connecting flanges  112  and defines a suspension aperture  116  through each of the four connecting flanges  112 . Each of the suspension apertures  116  are aligned with one of the apertures  56  of the cam plates  52  or one of the apertures  60  of the rear cam members  40  that is not used to connect the upper and lower frames  32 ,  44  to the front and rear cam members  36 ,  40 . The connecting member  96  is pivotally connected to the front and rear cam members  36 ,  40  by inserting a fastener  120  through each set of aligned apertures. The connecting member  96  is pivotal relative to the front and rear cam members  36 ,  40  about the fasteners  120 . 
   The springs  100  each include a hook  124  on each end thereof. The hooks  124  on one end of the springs  100  are hooked onto the upturned flanges  108  of the connecting member  96  and the hooks  124  on the other end of the springs  100  are hooked onto carriage flanges  128  of the suspension carriage  104 . The springs  100  are connected between the connecting member  96  and the suspension carriage  104  in tension, thereby biasing the suspension carriage  104  toward the flanges  108 . 
   The suspension system  24  further includes an adjusting mechanism or threaded rod  132  and a manually manipulatable handle  136  connected to and slidable along a first end of the rod  132 . The rod  132  is rotatably connected to the upper frame  32  and has the first end extending out of a front of the suspension system  24  and has a second end rotatably connected to the upper frame  32  at a rear of the suspension system  24 . The suspension carriage  104  is threadably connected to the rod  132  and is movable along the rod  132  in response to rotation of the threaded rod  132 . 
   With reference to  FIGS. 5–8 , the handle  136  is connected to the end of the rod  132  extending out the front of the suspension system  24 . The handle  136  defines a cavity  140  therethrough in which a surface or nut  144  of the threaded rod  132  is received. The nut  144  is connected to the rod  132  and is fixed for rotation with the rod  132 . The cavity  140  and the nut  144  have complementary shapes to one another, such that rotation of the handle  136  facilitates rotation of the threaded rod  132  in a similar direction. In the illustrated embodiment, the cavity  140  is a hexagonal shaped cavity and the nut  144  is a complementary hexagonal shaped nut. Accordingly, edges of the hexagonal shaped nut  144  engage sides of the hexagonal shaped cavity  140  to facilitate rotation of the cavity  140  and the nut  144  in the same direction. It should be understood that the cavity  140  may be many shapes, such as, for example any polygonal shape, and the nut  144  can also be many shapes complementary to the shape of the cavity  140 , such as, for example any polygonal shape, as long as rotation of the handle  136  facilitates rotation of the rod  132 . It should also be understood that the shape of the nut  144  does not have to exactly mirror that of the cavity  140  for the nut  144  and cavity  140  to be considered to have “complementary shapes,” as long as rotation of the handle  136  facilitates rotation of the rod  132 . 
   The handle  136  is slidable along a portion of the rod  132  and the nut  144  is slidable within the cavity  140  of the handle  136 . A boss  148  is positioned on one end of the cavity  140  to engage the nut  144  and limit movement of the handle  136  in a first direction out from the front of the suspension system  24  and a collar (not shown) is positioned around the rod  132  to engage the boss  148  and limit movement of the handle  136  in a second direction toward the front of suspension system  24 . The handle  136  is slidable along the rod  132  between an extended position, in which the nut  144  engages the boss  148 , and a retracted position, in which the boss  148  engages the collar. 
   With particular reference to  FIGS. 6–8 , the handle  136  also includes an engaging member or leaf spring  156  positioned within the cavity  140  and engagable with the rod  132  to resiliently resist sliding of the handle  136  along the rod  132 . The spring  156  includes an edge portion  160  engaging the boss  148  and partially wrapping therearound, a pair of non-resisting or flat portions  164  engaging a side of the cavity  140  and a resisting or raised portion  168  positioned between the flat portions  164  and spaced from the side of the cavity  140 . The boss  148  has a spring recess  172  defined therein for receiving the edge portion  160  of the spring  156 . The recess  172  is aligned with one of the hexagonal sides of the cavity  140  and assists in maintaining the spring  156  in proper alignment with the appropriate side of the cavity  140 . The recess  172  may be defined in alignment with any of the sides of the cavity  140  and, accordingly, the spring  156  may be aligned with any of the sides of the cavity  140 . 
   A pair of assembly apertures  176  are defined through the handle  136  and into the cavity  140 . The assembly apertures  176  allow a tool to access the nut  144  when the nut  144  is appropriately aligned with the assembly apertures  176  in order to connect or disconnect the nut  144  from the rod  132 . The handle may be disconnected from the rod  132  when the nut  144  is disconnected from the rod  132 . 
   Now that the components of the suspension system  24  have been described, operation of the suspension system  24  will be described. 
   With reference to  FIGS. 1–3 , when an operator sits in the seat  20 , the upper frame  32  is forced downward by the weight of the operator. Downward movement of the upper frame  32  causes the front and rear cam members  36 ,  40  to rotate in a clockwise direction (as viewed in  FIG. 1 ), which moves the connecting member  96  and, particularly, the upturned flanges  108  away from the suspension carriage  104  to extend the springs  100 . The suspension system  24  reaches a stable state when the weight of the operator is matched by the tension of the springs.  100  and the operator and seat  20  are suspended between the top (as shown in  FIGS. 1–3 ) and bottom of the full range of motion of the suspension system  24 . External forces may be applied to the suspension system  24  when the vehicle  28  is being operated. Such forces may be applied due to, for example, bumps in the terrain over which the vehicle  28  is traveling, braking or accelerating the vehicle  28 , etc., and may deflect the springs  100  and cause the upper frame  32  to move down toward the lower frame  44 . The springs  100  absorb such external forces and provide a more comfortable ride to the operator. The upper frame  32  returns to the top of the full range of motion when the operator dismounts the seat  20 . 
   With reference to  FIGS. 5–8 , the stiffness of the suspension may be adjusted by an operator. More specifically, the operator may grasp and pull the handle  136  along the rod  132  from the retracted position (shown in solid in  FIGS. 1–3  and  8 ), in which the handle  136  is substantially underneath the seat  20  and engages the collar, to the extended position (shown in phantom in  FIGS. 1 ,  2  and  8 ), in which the nut  144  engages the boss  148  and the handle  136  clears the front of the seat  20  and is rotatable without interference from the seat  20 . The engagement between the complementary shaped cavity  140  and nut  144  couples the rod  132  and the handle  136  for rotation together. Due to the threaded engagement between the rod  132  and the suspension carriage  104 , rotation of the rod  132  causes the suspension carriage  104  to move along the rod  132  either toward or away from the upturned flanges  108  of the connecting member  96 . 
   Once it is in the extended position, the handle  136  may be rotated clockwise and/or counterclockwise to extend and retract the springs  100  until the desired spring deflection and consequent spring “preload” is obtained. The further the springs  100  are deflected by the adjusting mechanism, the higher the preload and the stiffer the suspension. More specifically, movement of the suspension carriage  104  toward the upturned flanges  108  decreases the preload deflection of the springs  100  and softens the suspension, and movement of the suspension carriage  104  away from the upturned flanges  108  increases the preload deflection of the springs  100  and increases the stiffness of the suspension. After the stiffness of the suspension is set, the handle  136  may be pushed back along the rod  132  to the retracted position to inhibit snagging, bumping, etc. of the handle  136 . 
   With reference to  FIGS. 4 and 8 , the engaging member  156  engages the rod  132  to resiliently resist sliding of the handle  136  along the rod  132  under the weight of the handle  136  when the seat  20  and suspension system  24  are positioned in a non-horizontal position (see  FIG. 4 ). It should be noted that, for the seat illustrated in  FIG. 4 , only a portion of the weight of the handle  136  is directed along the length of the rod  132  because the threaded rod  132  is not vertical. The engaging member  156  only has to resist the portion of the weight of the handle  136  that would tend to cause the handle to slide along the threaded rod. 
   When the handle  136  is in the retracted position, the nut  144  is aligned with the leftmost (as viewed in  FIG. 8 ) flat portion  164  and the raised portion resiliently engages threads of the rod  132 . The leftmost edge (as viewed in  FIG. 8 ) of the raised portion  168  also engages the nut  144  and resiliently resists sliding of the nut  144  past the leftmost edge of the raised portion  168  and from the retracted position under the weight of the handle  136 . In order to move the handle  136  along the rod  132  in a direction out from the front of the suspension system  24 , a sufficient external force, such as, for example an operator pulling the handle  136 , must be applied to the handle  136  in a similar direction. Such external force will force the nut  144  against the leftmost edge of the raised portion and deflect the raised portion  168  toward the side of the cavity  140  to allow the nut  144  to pass by the raised portion  168 . With continued external force in the same direction, the nut  144  will slide into alignment with the rightmost flat portion  164  (as viewed in  FIG. 8 ) and abut the boss to position the handle  136  in the extended position (shown in phantom in  FIG. 8 ). In the extended position, the nut  144  is trapped between the rightmost edge (as viewed in  FIG. 8 ) of the flat portion  164  and the boss  148 . Engagement between the rightmost edge of the flat portion  164  resiliently resists sliding of the nut  144  past the rightmost edge and out of the extended position under the weight of the handle  136 . The handle  136  can be returned to the retracted position by supplying sufficient external force on the handle  136  in a direction toward the front of the suspension system  24  to deflect the raised portion  168  and move the nut  144  past the rightmost edge of the raised portion  168 . 
   Although particular constructions of the present invention have been shown and described, other alternative constructions will be apparent to those skilled in the art and are within the intended scope of the present invention. Thus, the present invention is to be limited only by the claims.