Patent Publication Number: US-2011057008-A1

Title: Spring assist system for vehicle-mounted racks

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/241,319, filed Sep. 10, 2009, the entire disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     The present invention relates to vehicle-mounted carriers or racks and particularly to hitch-mounted racks for carrying bicycles or other goods, the rack being pivotable downwardly away from the vehicle to improve access to the rear doors of the vehicle. 
     Rearwardly tiltable vehicle hitch-mounted support racks are known. See, for example, U.S. Pat. Nos. 5,181,822, 5,527,146 and 5,658,119; International Publication No. WO2006/004519 A1; and U.S. Patent Publication No. 2008/0099522 A1. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     A carrier for mounting in a hitch receiver at the rear of a vehicle. The carrier including a first tubular or base portion adapted to be inserted in the hitch receiver of the vehicle and a second beam portion adapted to carry bicycle mounting racks, or in other embodiments, racks for carrying other loads. The first and second portions are pivotally connected to each other such that the bicycle or load-carrying portion may be tilted downwardly to improve access to the rear storage area of a vehicle. 
     The carrier includes one or more spring mechanisms such as a gas assist cylinder and piston combination mounted to extend between the base portion and the beam portion to both slow the rate of downward tilting and assist in lifting the weight of the load carried on the beam portion. A bracket having a release lever is mounted on the beam portion and adapted to be interconnected with the gas assist cylinder and piston devices to allow the beam to be pivoted with or without loading or unloading the cylinder and piston combination. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a bicycle rack shown in the vertical position and including a gas assist cylinder and piston combination; 
         FIG. 2  is a perspective view of the bicycle rack of  FIG. 1  including an exploded view of one side of the gas assist cylinder and piston and its mounting structure; 
         FIG. 3  is a right side elevation view of a bicycle in the vertical position and showing the gas assist cylinder release lever in the locked position; 
         FIG. 4  is a right side elevation view of the rack of  FIG. 3  showing the gas assist cylinder release lever in the unlocked position; 
         FIG. 5  is a right side elevation view of the rack of  FIG. 3  showing the rack downwardly tilted and with the release lever in locked position; 
         FIG. 6  is a right side elevation view of the rack of  FIG. 3  showing the release lever in the unlocked position; 
         FIG. 7  is a bottom perspective view of the tube and beam portions of a second embodiment of a rack; 
         FIG. 8  is a bottom perspective view of the rack of  FIG. 7  including a pair of gas assist cylinders and pistons mounted thereon; 
         FIG. 9  is a left side elevation view of the rack of  FIG. 8 ; 
         FIG. 10  is a left side elevation view of the rack of  FIG. 8  in the downwardly tilted position; 
         FIG. 11  is a left side elevation view of the rack of  FIG. 8  in the upright storage position; 
         FIG. 12  is a front perspective view of the rack of  FIG. 8  including the bicycle mounting elements interconnected with the beam portion of the rack and including a pair of bicycles mounted thereon; 
         FIG. 13  is a left side elevation view of the bicycle rack of  FIG. 12 ; and 
         FIG. 14  is a left side elevation view of the bicycle rack of  FIG. 12  shown in the downwardly tilted position. 
         FIG. 15  is a partial perspective view of the gas assist cylinder and piston combination including a pair of coil springs. 
     
    
    
     DETAILED DESCRIPTION 
     Referring initially to  FIGS. 1-6 , a vehicle-mounted rack  10  is disclosed including a tubular base portion  12  adapted to be inserted and mounted in the hitch receiver of a vehicle, such as a van or the like, having a rear door or doors. Extending upwardly from the base portion is a first beam member  14  and a second beam member  16  mounted rearwardly thereof vis-à-vis the vehicle. Beam members  14  and  16  are pivotally mounted at their base and extend upwardly to, and are pivotally mounted to, support arms  18 . A spring-loaded pull pin  20  is provided to extend through second beam member  16  and through a corresponding hole in plate  22  to lock the rack in its upright position. Referring additionally to  FIG. 2 , a notch  24  may be provided in plate  22  for engagement with pull pin  20  to lock the rack in its forwardly tilted position as best seen in  FIGS. 5 and 6 . 
     The pivoting interconnection of the first and second beam members with base portion  12  and support arms  18  forms a substantial parallelogram such that when rack  10  is tilted forwardly, support arms  18  remain in a substantially horizontal position so that loads mounted thereon are not dislodged. Said base portion includes a pair of base plates  26  to pivotally interconnect the first and second beam members  14  and  16  with base portion  12  by means of pins or the like extending through the base plates and the bottom portions of the first and second beam members. The structure and operation of this rack is more fully disclosed in U.S. Patent Publication No. 2008/0093404-A1, which is hereby incorporated by reference into this application. 
     Referring again to  FIG. 1 , a spring mechanism such as a gas assist cylinder  28  and cooperating piston  30  are shown mounted to extend between base plate  26  and a slotted bracket or fitting  32  as seen in  FIG. 2 . Fitting  32  is welded or otherwise affixed longitudinally to the forward portion of beam  14 . While not illustrated in  FIG. 2 , it will be understood that a pair of pistons and cylinders  28  and  30  may be mounted on opposite sides of carrier  10  and interconnected by upper pin  34  and lower pin  36 . Pins  34  and  36  extend through spacers  38  and  40  and cooperating fittings  42 , and  44 , connected, respectively, to the end of the piston rod  30  and to the end of the cylinder  28 . Pin  36  also mounts the lower end of pivotable beam member  16  to the pair of base plates  26 . The ends of pins  34  and  36  are held in place by cooperating washers  46  and retaining rings  48 . Referring to  FIG. 15 , to take up any looseness in the connection and to prevent rattle, coil springs  47  may be placed adjacent the spacers  38  and  40 , or elsewhere on pins  34  and  36 . 
     While the spring mechanism illustrated in the preferred embodiment is shown to be a gas assist cylinder and piston combination, it will be understood that other mechanisms capable of operating as a spring may alternatively be used including a gas spring with dampening oil inside the cylinder, coil springs, or leaf springs. 
     Release lever  50  is mounted on conventional pivot pin structure  51  at the upper end of bracket or fitting  32 . The release lever comprises a U-shaped channel adapted to fit over bracket  32  when in the closed position, thus forming a blocking means preventing movement of the end of piston rod  30  in slot  52 . 
       FIGS. 2 and 4  show pivotal release lever  50  in the open position. In this position, the end of piston rod  30  may slide longitudinally in slot  52  of fitting  32  such that when the rack is tilted downwardly, no force is applied to press piston rod  30  into cylinder  28  to compress the gas therein and thereby slow the rate of tilting of the rack  10 . See  FIG. 6  also. 
     In  FIGS. 3 and 5 , however, release lever  50  is shown in the downward, locked and blocking position where it prevents the end of piston rod  30  from sliding in slot  52  such that when rack  10  is tilted rearwardly, as best seen in  FIG. 5 , piston rod  30  is pressed downwardly into cylinder  28  to compress the gas within the cylinder, thus not only slowing the tilting of the rack, but also storing energy which can later be used to assist in raising the rack to its original upright position. 
     It is also contemplated that the spring mechanism could be fixedly attached to extend between beams  14  and  16  such that the spring mechanism would always be operable. For example, a first end of the spring mechanism could be attached to beam  14  a vertical distance above its connection to base portion  12  while the second end of the spring mechanism is connected to beam  16  near its base. Other connection points are also contemplated. 
     It will be understood that when a load is placed upon support arms  18  when the carrier is in its upright position, release lever  50  will be moved to the closed and locked position. However, when it is desired to tilt rack  10  when there is no load on the rack and it is simply desired to move the rack out of the way so that the rear doors of the vehicle may be opened, releasing the lever  50  allows the rack to tilt freely without encountering any resistance from the gas assist piston and cylinder  28  and  30 . 
     The combination of the spring mechanism such as a gas assist cylinder and piston and the parallelogram rack creates a novel and improved vehicle mounting rack which assists in overcoming the serious problems encountered when tilting and raising a rack supporting a significant load such as would be encountered when four bicycles are mounted thereon. The gas assist piston and cylinder combinations, both prevent the rack from tilting too rapidly, which can be both dangerous to the user and damaging to the rack and its load and, in addition, the stored energy in the compressed gas cylinder assists in raising the rack from the downwardly tilted position. Notch  24  is provided in plate  22  to receive pull pin  20  to hold the rack in a tilted position so that the stored energy in the cylinder and piston combination does not raise the rack prematurely. Once spring-loaded pull pin  20  is pulled out of notch  24 , however, and the rack begun to be raised, piston  30  is pushed out of cylinder  28  by the compressed gas to assist in raising the rack. 
     As shown in  FIGS. 2-6 , cylinder  28  is mounted to base plate  26  by means of pin  36 , while piston  30  rides in the slot  52  of fitting  32 . It will be understood, however, that the position of the piston rod and cylinder may be reversed. 
     Turning now to  FIGS. 7-11 , cylinder  28  and piston rod  30  are shown mounted on a second form of vehicle-mounted rack  54  comprising a base portion  56  which is adapted to be received into a hitch receiver at the rear of a vehicle, and a beam portion  58  which is pivotally connected thereto by a pair of plates  60  and  62  positioned on the opposite sides of the base portion and the beam portion, and conventional fasteners such as nuts and bolts, the beam portion  58  may pivot both downwardly and upwardly with respect to base portion  56 . The structure and operation of this rack is more fully disclosed in U.S. Patent Publication No. 2008/0099522-A1, which is hereby incorporated by reference into this application. 
     Referring additionally to  FIG. 9 , the forward end of cylinder  28  is shown connected to cantilevered mounting plate  64  disposed on the bottom of base portion  56 . It will be understood that cylinder  28  is mounted to pivot with respect to mounting plate  64 . The end of piston rod  30  is mounted to move longitudinally in slot  66  of bracket  68  which is welded or otherwise mounted to extend longitudinally on the bottom of beam  58 . As best shown in  FIG. 7 , bracket  68  may include a pair of downwardly extending longitudinal members, each of which includes a slot  66  in which the end of piston rod  30  moves. 
     Referring additionally to  FIG. 8 , an alternate embodiment in which a pair of spring mechanisms such as parallel gas assist cylinders comprising cylinders  28  and piston rods  30  are shown. The use of a pair of spring mechanisms would create additional force to assist in either slowing the tilt of beam  58  downwardly or raising it upwardly. The use of single or double gas assist cylinders, or cylinders of greater or lesser size, is a matter of choice to be determined by the parameters of the rack design and the load to be carried. 
     Turning now to  FIG. 10 , rack  54  is shown in the downwardly tilted position. When so tilted, piston rod  30  is moved into cylinder  28  to compress the gas therein. The end of piston rod  30  remains pressed against the end of slot  66  while cylinder  28  moves within slot  66  as the piston rod  30  moves into the cylinder. Again, it will be understood that either single or double sets of gas assist cylinders as shown in  FIG. 8 , may be used. It has been found that a pair of 130-pound rated gas assist pistons works satisfactorily to handle normal bicycle rack loads, but it will be understood that gas assist cylinders of larger or smaller ratings could be used as required in either this embodiment or the embodiment of  FIGS. 1-6 . 
     Turning now to  FIG. 11 , beam  58  is shown pivoted upwardly such as would be the case when it is not loaded and it is desired to reduce the length which the rack extends rearwardly of the vehicle. In this configuration, the distal end of piston rod  30  moves to the proximal end of slot  66 . In this arrangement, the gas within cylinder  28  is not compressed. The cantilevered mount of plate  64  allows cylinder  28  to be moved to the vertically upright position when the beam is tilted upwardly for storage. 
       FIGS. 12-14  illustrate the rack of  FIGS. 7-11  with structure for holding a pair of bicycles mounted to pivoting beam portion  58 . The full details of this bicycle mounting structure may be seen in U.S. Patent Publication No. 2008/0099522-A1 identified above and incorporated herein by reference. As shown in  FIGS. 12 and 13  bicycles  70  and  72  are carried in an upright position on the rear of a vehicle. When access to the rear doors of the vehicle is needed, a spring loaded pull pin is withdrawn from its locked position such that the beam portion  58  tilts downwardly. As the beam tilts downwardly, piston rod  30  moves toward cylinder  28  to compress the gas within cylinder  28  thus slowing the speed at which beam portion  58  tilts. Controlling the speed of the tilting motion reduces the risk of injury to the user or damage to the load which could be caused by the sudden tilting of a heavy load if it were not properly controlled by the user. When it is desired to return beam portion  58  to its horizontal position as shown in  FIGS. 12 and 13 , the force of the compressed gas within cylinder  28  helps the user tilt the load upwardly. This is particularly important when the load being carried on beam  58  is a heavy one. 
     In some instances where it is desired to carry a load other than bicycles, the bicycle carrying structure shown in  FIGS. 12-14  may be replaced by a tray type carrier mounted on beam portion  58 . Such a carrier is illustrated in the U.S. patent publication identified above and incorporated herein by reference. This type of carrier may support loads much heavier than bicycles, thus making the benefit of the spring assist design even more important when beam portion  58  is tilted downwardly or upwardly. 
     While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.