Abstract:
A seat assembly for a motor vehicle includes an air spring suspension system for effectively isolating the occupant of the vehicle&#39;s seat from shock, vibration and inertial forces directed along both a vertical axis and a horizontal axis. A stationary base plate member is attached to the floor of the vehicle and it supports a pivot linkage assembly joining the stationary base member to a movable base member. An air spring is disposed between the stationary base member and the movable base member to displace the movable base member in a generally vertical direction to an extent allowed by the linkage assembly. Supported atop the movable base member is a seat slide assembly that permits fore and aft adjustment of seat position within the vehicle. A vehicle seat mount is affixed to the pair of slide members and includes shock absorbing springs that are disposed between the slide members and the vehicle seat mount for cushioning inertial forces due to acceleration and braking. Associated with the air bag is a control switch that operates to selectively inflate and deflate the air bag to offset vertically directed inertial forces acting on the seat assembly.

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     This invention relates generally to vehicle seats, and more particularly to vehicle seats which are effectively isolated from the effects of road shock and forces due to sudden acceleration and deceleration of the vehicle. 
     II. Discussion of the Prior Art 
     It is well known that semi-tractor trucks and other truck-type commercial vehicles tend to have a relatively stiff suspension system whereby shock and vibration forces occasioned from traversing road bumps and the like are effectively transmitted to the driver or passenger to be lurched forward or rearward depending upon the magnitude of the deceleration and acceleration vectors. 
     To improve the comfort of the ride, it is desirable, as much as possible, to isolate the seat occupant from these types of inertial forces. There are disclosed in the prior art various systems for isolating a vehicle driver or passenger from bouncing or jolting in the vertical direction, but compensation for fore and aft translation due to acceleration and deceleration have largely not been addressed. For example, in the Thompson et al. U.S. Pat. No. 3,990,668, a vehicle seat is described which incorporates a hydraulic actuator coupled in circuit with a valve whose spool is directly connected by linkages to the seat. The valve is operative to change the response of an accumulator coupled to the actuator so as to cushion the ride and to accommodate large excursions from a predetermined ride position due to major shocks. The Thompson et al. reference has no provision for cushioning or dampening fore and aft movement of the seat system. 
     Other prior art patents incorporate pneumatic cylinders or air bags operate strictly to adjust the height of the seat above the floor so as to accommodate drivers/passenger of differing physical stature. In this regard, reference is made to the Costin U.S. Pat. No. 3,954,245 and the Misher et al. U.S. Pat. No. 4,638,982. Neither of these patents teaches a seat construction for minimizing or nulling out fore and aft sway of the seat under breaking and accelerating conditions, respectively. 
     In U.S. Pat. No. Re. 35,572, which is assigned to the assignee of the present application, a seat construction is disclosed which minimizes the fore and aft sway of the seat. The device shown in that patent uses both horizontally and vertically disposed air bags operating in cooperation with springs to dampen motion. Also utilized is a plurality of vertical hydraulic vibration dampeners. While the system described in the &#39;572 patent has proven to be commercially successful, it has a comparatively high cost of manufacture which impacts the profit margins achievable. 
     The present invention is advantageous over U.S. Pat. No. Re. 35,572 due to new concepts included in its simplified and scaled-back design. Some differences include a single air bag for dampening in the vertical direction without multiple hydraulic vibration dampeners and the use of a spring and slide rod arrangement for horizontal dampening dispensing with the need for a horizontally disposed air bag. This design enables effective isolation of forces exerted in both the vertical and horizontal direction at a substantially reduced cost. Moreover, because the stabilizing linkages and hydraulic dampener employed between the units stationary base and movable base can pivot, a greater range of vertical displacement of the seat can be achieved. 
     SUMMARY OF THE INVENTION 
     The present invention provides for a seat assembly which is adapted to be attached to the floor of a motor vehicle, such as a semi-tractor. The assembly includes a stationary base or mounting plate which is attached to the vehicle&#39;s floor board and forms the bottom of a box-like housing. A movable base member is pivotally joined to the stationary base member by linkages. Mounted on a pedestal within the box-like housing is a means for displacing the movable base member along a path determined by the linkages. This means may comprise a vertically oriented air spring support frame which is slide mounted and free to move back and forth in the fore and aft direction when manually unlatched by the seat&#39;s occupant, whereby the seat position can be set to accommodate the person&#39;s stature. The upholstered seat is secured to that latter slide assembly. To dampen out any tendency of the seat to oscillate due to uneven road surfaces, a hydraulic cylinder is operatively coupled between the stationary base member and the movable base member. 
     A control means for adjusting the relative height of the vertically displaceable seat-supporting frame is coupled to the vertically disposed air spring. The control means allow for inflating or deflating of the air spring based upon the user&#39;s desired seat height. 
     Horizontally disposed springs disposed on roller-supported, guide-rods act to cushion horizontal motions of the seat due to acceleration, braking and other generally horizontally directed forces encountered in the over-the-road travel. 
    
    
     These and other objects, features, and advantages of the present invention will become readily apparent to those skilled in the art through a review of the following detailed description in conjunction with the claims and accompanying drawings in which like numerals in several views refer to the same corresponding parts. 
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the seat assembly of the present invention; 
     FIG. 2 is a perspective view of the seat assembly in the raised position; 
     FIG. 3 is a front perspective view of the seat assembly in the raised position; 
     FIG. 4 is a rear perspective view of the seat assembly in the raised position; 
     FIG. 5 is a left side perspective view of the seat assembly; and 
     FIG. 6 is a right side perspective view of the seat assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention represents broadly applicable improvements for seat apparatus design to isolate shock and vibration in motor vehicle seats. The embodiments herein are intended to be taken as representative of those in which the invention may be incorporated and are not intended to be limiting. 
     Referring first to FIG. 1, there is shown a perspective view of the seat support assembly, on which an upholstered seat and seat back, such as illustrated in the &#39;572 patent (the teachings of which are hereby incorporated by reference), is mounted. The assembly itself is indicated generally by numeral  10  and includes a box-like housing  12  made up of a movable base member  15  and a stationary base member  13 . The stationary base member  13  is comprised of front panel  14 , lower right side panel  16 , lower left side panel  18 , and floor member  20 . The movable base member is comprised of upper right side panel  22 , upper left side panel  24 , vertically displaceable top panel  26 , and rear panel  28  (FIG.  3 ). Means are disposed between the stationary and movable base members for displacing the movable base members relative to the stationary member. More particularly, there is contained in the stationary housing, an air spring  30  and two pairs of parallel upper frame support linkages  32  and  34 . 
     Also shown in FIG. 1 are slide rail assemblies  36  and  38  which enable movement in the fore and aft direction. Located above the slide rails are slide rods  40  and  42 . Finally, front seat mount plate  44  and rear seat mount plate  46 , to which the upholstered vehicle seat is adapted to be mounted, are indicated as well. 
     With reference to FIG. 2, it can be seen that the seat assembly is in a raised position when compared to FIG. 1, allowing a more detailed examination of its features. Starting with housing  12 , the floor member  20  is a flat panel adapted to be bolted to the floor of the vehicle. The exposed floor member surface has two raised cylindrical tubes of rubber  48  and  50  thereon near the back edge thereof as cushioning bumpers for the above features to rest against when the seat is in its lowermost position. The upper surface of floor member  20  also has a metal clevis  52  welded or otherwise affixed to it for mounting a cylinder  53  of a hydraulic dampener  54 . The floor member also supports a rectangular pedestal  56 , approximate its center, upon which air spring  30  sits. For another view of these elements also see FIG.  4 . 
     Front panel  14 , lower right side panel  16 , and lower left side panel  18  each project vertically upward from floor member  20 . Front panel  14  is a rectangular piece of sheet metal which extends across the front of the housing. 
     Side panels  16  and  18  are somewhat L-shaped flat panels aligned along the side edges of floor member  20 . There are also two large, vertically aligned holes  60 ,  62  (FIG. 2) and  64 ,  66  (FIG. 5) on each of the side panels of the lower stationary housing  13  near the front ends of the opposed side panels. The center line of hole pairs  60  and  64  and of hole pair  62  and  66 , are aligned with two parallel, cylindrical metal tubes  68  and  70 , respectively, that form part of a linkage assembly for guiding movement of the movable base member when the air spring  30  is inflated and deflated. The tubes  68  and  70  are contained between the side panels, but are journaled on their ends using transversely extending pins  71  which pass through bushings (not shown) fitted into the holes. The pins are free to spin in the interior diameter of tubes  68  and  70 . A C-shaped spring clip  75  fits in a groove on each end of the pins. The purpose of the clips is to prevent the pin  71  from moving longitudinally by creating a diameter too large to fit through the side panel holes, but still allowing the pin to freely rotate within its bushing and within the respective one of the tubes  68 ,  70  through which it passes. 
     Tubes  68  and  70  have welded near each of their ends, just inside the housing sidewalls, one of the four arms or stabilizing bars  72 ,  74 ,  76 , or  78 , which also form part of the linkage assembly. These stabilizing bars are oriented perpendicular to the tubes  68  and  70  to which they are fastened and are configured into two pairs of parallel tubular bars. Also, one pair of parallel arms or stabilizing bars has a stop  80  located between the bars. 
     Referring now to FIG. 3, a stub shaft  81 , on the left side of the assembly, is attached to a piston rod end  82  of hydraulic dampener  54 . This dampener aids the air spring  30  in the reduction of forces exerted upon a user in the vertical direction. 
     Also shown in FIG. 3 is how the arms or stabilizing bars  72 ,  74 ,  76 , and  78  comprising the linkage assembly are welded to transversely extending tubes  84  and  86  which extend parallel to the back of the upper housing  15  in the same manner as the tubes  68  and  70  span the lower housing  13 . 
     The upper housing member  15  contains a rear panel  28  which traverses across the back of the housing. It contains three small holes  88  for bolts used to attach it to a decorative cover (not shown). Also connected to the top plate of the upper housing are upper side panels  22  and  24 . The side panels are somewhat L-shaped and roughly fit opposite the outline of the space defined by the lower side panels  16  and  18 . The transverse width of the upper side panels is narrower than the width of the lower side panels. This difference in transverse width enables the upper side panels to nest inside the lower side panels when the assembly  10  is in its lowered position seen in FIG.  1 . It is, of course, possible to make the size of the upper movable base member greater than that of the lower stationary base member so that the lower base member nests within the upper base member when in its lowered position. 
     In addition, there are four large holes  89  in the upper portion of the housing, one pair on each upper side panel, to which the axis of parallel cylindrical metal tubes  84  or  86  is aligned. In the same manner that cylindrical metal tubes  68  and  70  of the linkage assembly are journaled in the holes in the lower side panels  16  and  18 , the cylindrical metal tubes  84  and  86  are journaled by pins  83  passing through the holes in the upper side panels  22  and  24  and through the tubes  84  and  86 . On each end of the pins  83 , which extend outside the side panels, is a conventional C-clip fastener  87 . To prevent the pin  83  from moving longitudinally along its axis, the diameter of the C-clip is too large to fit through the side panel holes, but allows the pin to freely rotate within bushings disposed in the holes in the side panels. 
     The rear panel  28  and upper side panels  22  and  24  project vertically downward from vertically displaceable top panel  26  of the movable base member. Top panel  26  is a flat, rectangular piece of sheet metal which contains means to mount the upper cylindrical member  90 , of air spring  30 , to the center of its downward facing surface. At the center surface of the top panel  26  is a fitting hole  91  which connects to an angled tube fitting  92 . This tube fitting  92  contains a hexagonal nut  94  for tightening to the hole and enables a connection to an air tube  96 , providing pneumatic air pressure to the air spring  30 . It is due to this air pressure, that air spring  30  is able to push up against the downward facing surface of top panel  26  and raise the level of the seat in a manner yet to be explained. The air spring can be inverted such that the fitting  92  is proximate the bottom of the lower stationary base member. In this way, the air fitting does not interfere with other structures. 
     The upward facing surface of top panel  26  contains an L-shaped clip  98  which is attached with a screw to the front of the top panel and is angled downward over the front edge of top panel  26  and contains another screw through the angled portion. The clip  98  is included to later facilitate hanging a skirt or decorative covering which hides the housing components from view. 
     As seen in FIG. 4, the top panel&#39;s upward facing surface also has slide rails  36  and  38  mounted along, and parallel to, its right and left sides. The slide rails  36  and  38 , on the vertically moveable top plate  26 , comprise a part of the seat mount assembly which is seen to include upper C-shaped channels  100  and  102  bolted to the flat spacer bars  104  and  106 . The elongated C-shaped channels fit over the outwardly extending flanges of U-shaped channels  108  and  110  which are bolted to the upper surface of the vertically moveably top plate  26 . Because of the manner in which the C-shaped channels  100  and  102  and U-shaped channels  108  and  110  interact, the two can slide back and forth relative to one another but cannot be separated. 
     The lower U-shaped channels  108  and  110  have a plurality of notches  112  formed at regularly spaced intervals along their lengths. A first latch plate  114  is pivotally joined by a rivet or pin  116  to the upper surface of the C-shaped channel  100 . A second latch plate  118  is pivotally joined by a pin  120  to the upper surface of C-shaped channel  102  as well. These two latch plates each have a pair of fingers  122  and  124  positioned to penetrate through a pair of adjacent notches  112  when urged in position by springs  126  and  128 . The latch plates are joined together by a latch cable  130 . Lever  132  is joined to the first latch plate  114 . Moving this lever would enable the fingers of the latch plates to disengage from their respective notches with the cooperation of latch cable  130 , which joins the latch plate members. In general, the latching elements are very similar to those disclosed in U.S. Pat. No. Re. 35,572 by Lloyd et al. although the present invention has the addition of latching member components on both seat rail slides, not on just one. 
     As seen in FIG.  5  and FIG. 6, also forming part of the vehicle seat mount assembly and located above slide rails  36  and  38  are two spacer bars  104  and  106 . They are bolted at their ends to the upper C-shaped channels  100  and  102 . Spacer bars  104  and  106  are metal bars which are approximately the same width and length as the tops of the C-shaped members they rest upon. The bars flatly engage against members  100  and  102  at their ends, but angle upward slightly in the center forming a raised, flat plateau. Each of four roller support brackets  138  are welded on top of the ends of the spacer bars  104  and  106 . The roller support brackets  138  journal grooved metal rollers  140  which serve to guide slide rods  40  and  42  in moving in a horizontal direction. The grooved rollers  140  rotate freely around axels  142  extending through holes in the sides of the roller support brackets  138 . The slide rods  40  and  42  move smoothly in the fore and aft direction on the rollers  138 , but are limited in travel by shock absorbing coiled springs  144  disposed on each end of the slide rods, pushing against a blocking piece  146  attached to the roller support bracket  138  members. The slide rods are capable of moving a maximum distance which equals the length of the slide rods  40  and  42  that extend outwardly from one of the blocking pieces  146 . Capping the ends of the slide rods  40  and  42  are upper bars  148  and  150 . These bars run parallel to the slide rods  40  and  42  and are located a distance above the roller supports  138  so as to allow for a small space of clearance. The upper bars  148  and  150  are flat except for their ends which bend  90  degrees downward and cap the ends of slide rods  40  and  42 . 
     On the left side of the assembly, an angled piece of metal is mounted with screws to upper bar  150 . This piece of metal is called a “vertical control plate”  152 . This plate extends horizontally outward from the side of the remainder of the assembly, then is angled downward. The downward face supports a control means that includes a three position pneumatic control switch  154 . This switch contains two hose connections  156  and  158  on its interior side seen in FIG.  4 . The upper connection  156  attaches to tube  96 , which in turn ends in attachment to angled tube fitting  92  leading into the air spring  30 . The second hose connection  158  attaches to a hose (not shown) leading to a source of pressurized air located elsewhere in the vehicle and commonly used to operate the vehicle&#39;s air brakes. 
     The last elements of the vehicle seat mount assembly are the front mount plate  44  and the back mount plate  46 . These structures are welded across the front and back of upper bars  148  and  150 . Front mount plate  44  contains three bolt holes  160  for mounting, two of these located parallel to one another across its front edge. The back mount plate  46  contains two bolt holes  162  located parallel to one another across its back edge. These mount plates form the base upon which the upholstered vehicle seat is secured. Mounting the seat is accomplished by attaching inserted bolts through the mount plate holes. 
     Now that the details of the mechanical construction of seat assembly  10  of the present invention have been described, consideration will next be given to its mode of operation. 
     Upon entering the vehicle, if the driver determines that for comfort, the seat and seat back should be repositioned to provide a comfortable distance between the truck&#39;s clutch, brake and accelerator, the operator may displace the actuator lever handle  132  relative to the side of the seat and, in doing so, will pivot the latch plate  114  about a pin  116  causing fingers  122  on latch plate  114  to disengage from a pair of notches  112  formed through the wall of the channel member  108  attached to the upper surface of top panel  26 . Latch plate  114  is attached to a cable  130  on the opposite side of the pin. This cable is attached to another latch member  118  which is engaged in notches  112  formed in channel member  110 . The movement of lever  132  provides a pull on cable  130  which, in turn, pivots latch member  118  and disengages the fingers from the notches  112  in channel member  110 . With the fingers disengaged, the seat may be slid forward or rearward to a desired position along the rails  108  and  110 . Releasing the lever  132  allows the return springs  126  and  128  to pull the fingers  122  and  124  of the latch plates back into engagement with the serrated openings on the slide members  108  and  110 , thus again locking the mating slide channels to one another. 
     During vehicle travel, forces acting in the fore and aft direction caused by acceleration and braking will be effectively cushioned by the horizontally disposed shock absorbing compression springs  144  as the seat moves with the slide rods  40 ,  42 . The force of the coiled springs  144  normally urge the sliding vehicle seat to a central position balanced between the force of all four coiled springs. 
     The vertically directed air spring  30 , along with hydraulic dampener  54  and the pivotable linkage assembly are used to control the elevation of the seat and to dampen out any vertically directed forces which the vehicle may encounter, thus tending to isolate the occupant of the seat assembly from vertically directed shock and vibration. For example, upon hitting a bump in the road, a tendency exists for the seat and the occupant to first be lifted relative to the truck&#39;s floor and then fall due to the weight of the operator. The hydraulic dampener  54  not only maintains the bottom of the seat in a level plane, but it tends to dampen out any tendency for the seat to vibrate or oscillate due to these sudden vertically directed forces impinging on the seat. 
     One last important feature to note is the method by which the vertical travel of the seat is limited. As the seat is elevated, the space between the parallel bars  72  and  74  decreases. When this occurs, a limit is reached when the stop  80 , affixed to the lower bar  74 , comes into contact with the upper bar  72 . This limits further upward movement of the seat affixed to the top panel  26 . 
     It can be seen, then, that the present invention provides an improved, flexible and efficient apparatus for mounting a seat within a motor vehicle which functions to effectively isolate the occupant from bearing shock and vibration commonly encountered by semi-truck drivers. The result is that there is less fatigue and soreness experienced by the diver and improved highway safety. 
     This invention has been defined herein in considerable detail in order to comply with the Patent Statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment details and operating procedures, can be accomplished without departing from the scope of the invention itself.