Abstract:
A winch assembly is provided for use with a tire carrier having a mounting plate. The winch assembly includes a spool, a torque limiter and a housing. The housing has a closed end and an open end. The open end is adapted to be fixedly secured to the mounting plate to define a single cavity between the closed end and the mounting plate for substantially enclosing both the spool and the torque limiter therein.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to a tire carrying device for raising and lowering a wheel between a storage position and an access position. More specifically, the invention relates to a winch assembly of the tire carrying device.  
         [0003]     2. Description of the Related Art  
         [0004]     Tire carrying devices are commonly used in automotive vehicles for raising and lowering a tire between a storage position disposed against an underside of the vehicle and an access position spaced apart from the underside of the vehicle to facilitate access to the tire. A tire carrying device usually includes a winch assembly that includes a spool, a flexible tether wrapped around the spool and having a free end attached to the tire, and a torque limiter operatively coupled to the spool to prevent overloading of the cable during raising of the tire to the storage position.  
         [0005]     An example of a tire carrying device is disclosed in U.S. Pat. No. 6,554,253 (“the &#39;253 reference”) issued to Dobmeier et al. on Apr. 29, 2003. The &#39;253 reference discloses first and second chambers or housings for separately enclosing the spool and torque limiter, respectively. Another tire carrying device is disclosed in U.S. Pat. No. 5,524,870 issued to Tallent et al. on Jun. 11, 1996. The Tallent reference discloses first and second housing components for separately housing the clutch and spool, respectively.  
         [0006]     It remains desirable to provide a winch assembly for a tire carrying device that is less expensive and easier to manufacture than previously known tire carrying devices.  
       SUMMARY OF THE INVENTION  
       [0007]     According to one aspect of the invention, a winch assembly is provided for use with a tire carrier having a mounting plate. The winch assembly includes a spool, a torque limiter and a housing. The housing has a closed end and an open end. The open end is adapted to be fixedly secured to the mounting plate to define a single cavity between the closed end and the mounting plate for substantially enclosing both the spool and the torque limiter therein. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
         [0009]      FIG. 1  is a cross sectional view of a tire carrying device according to the invention;  
         [0010]      FIG. 2  is a top perspective view of a housing for a winch assembly in the tire carrying device;  
         [0011]      FIG. 3  is a top view of a spool in the winch assembly;  
         [0012]      FIG. 4  is a bottom view of the spool as a tether is being assembled to it;  
         [0013]      FIG. 5  is a bottom view of the spool with the tether assembled to it; and  
         [0014]      FIG. 6  is a bottom perspective view of the housing. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     A tire carrying device  10  for carrying a spare tire T of a vehicle is shown in  FIG. 1 . The tire carrying device  10  includes a tire carrier  12  which is connected to a winch assembly  14  by a tether or cable  16 . Preferably, the tire carrier  12  is a two-part carrier. The winch assembly  14  is operable to raise and lower the tire carrier  12  and tire T. The winch assembly  14  includes a mounting plate  18  which has a receiver tube  20  extending from a lower side of the mounting plate  18  to receive a top portion of the tire carrier  12 . A latch  22  is mounted to the receiver tube to engage a top portion of the tire carrier to support the tire carrier in the event the cable separates. The tire carrier  12  and latch  22  may be of any suitable type known by those skilled in the art. Examples of the tire carrier  12  and the latch  22  are shown in U.S. Pat. No. 6,554,253 issued to Dobmeier et al. on Apr. 29, 2003, which is incorporated herein by reference in its entirety. A winch housing  40  according to the invention is mounted to an upper side of the mounting plate  18 .  
         [0016]     The winch assembly  14  includes a shaft  24  and a sheave or spool  26 . The spool  26  is rotatably coupled to the shaft  24  and housing  40 . The spool  26  includes a slot or groove  27  formed around the periphery for receiving the cable  16  as the tire carrier  12  is raised. The cable  16  extends between a fixed end fixedly secured to the spool  26  and a free end fixedly secured to the carrier  12 . Described in greater detail below, a generally rigid sleeve or end fitting is fixedly secured to the fixed end of the cable  16 . In turn, the end fitting is pivotally coupled to the spool  26  at the bottom of the groove  27 .  
         [0017]     A torque limiter  28  is operatively coupled to the shaft  24  to prevent overloading of the cable  16 . More specifically, the torque limiter  28  includes a pair of friction plates  30 ,  32 . An upper friction plate  30  extends from a drive nut portion  34  adapted to interconnect with a crank handle. A lower friction plate  32  is drivingly connected to the spool  26  via a gear reduction mechanism  36 , preferably a taumel-type arrangement. Specifically, the lower friction plate  32  is coupled to the shaft  24  for rotation therewith. A biasing member  68 , preferably a belleville spring, is continuously energized between the housing  40  and the torque limiter  28  for axially compressing the friction plates  30 ,  32  together. The biasing member  68  has a predetermined spring rate, such that beyond a predetermined level of torque, the upper  30  and lower  32  friction plates will slip relative to each other to prevent overloading of the cable  16 .  
         [0018]     The gear reduction mechanism  36  includes a ring gear  37 , a planetary gear or actuator  38  and an eccentric cam  39 . The ring gear  37  is integrally formed or fixedly secured to the spool  26 . The ring gear  37  includes a plurality of teeth. The actuator  38  includes a plurality of teeth  38 a, shown in  FIG. 6 , for engaging the teeth of the ring gear  37 . The actuator  38  has at least one less tooth than the ring gear  37 , thereby defining the reducing function of the gear reduction mechanism  36 . The eccentric cam  39  is fixedly secured to the shaft  24 . The actuator  38  includes a center bore  41  for receiving the eccentric cam  39  therein. The cam  39  drives the actuator  38  in a reciprocating manner about the ring gear  37  in response to rotation of the shaft  24 . As best shown in  FIG. 6 , the actuator  38  includes a step or arm  43  that remains rotatably constrained between opposing and spaced apart walls  45   a,    45   b  defined in the housing  40 . The walls  45   a,    45   b  prevent rotation of the actuator  38  relative to the housing  40 , but at the same time allow the actuator  38  to wobble about the teeth of the ring gear  37 . The wobbling actuator  38  causes rotation of the spool  26  relative to the housing  40 . Rotation of the spool  26  causes winding or unwinding of the cable  16  about the spool  26 , thereby raising or lowering the carrier  12  between a storage position and an access position.  
         [0019]     As shown in  FIGS. 2 and 6 , the housing  40  has a side portion  42  which extends from a peripheral edge  44  of a domed portion  46 . The housing  40  has an inner surface  48  defining a cavity housing the torque limiter  28  and spool  26 . The side portion  42  is generally cylindrical to extend closely about the spool  26  to maintain the cable  16  on the spool  26 . The side portion  42  includes a flared portion  42   a.  An abutment block  49  is nestingly supported in the flared portion  42   a.  The flared portion  42   a  and block  49  have corresponding slots  53 ,  55  through which the cable  16  exits the housing  40 .  
         [0020]     The domed portion  46  covers the torque limiter  28 . The domed portion  46  has a generally flat center  50  in which a throughbore  52  is formed to receive the drive nut portion  34 . Flange  54  extends inwardly from the inner surface  48  of the domed portion  46 . Each flange  54  has a radially extending edge  56  formed to position an upper surface of the spool  26  and an axially extending edge  58  to position the friction plates  30 ,  32  of the torque limiter  28 . Preferably, at least three flanges  54  extend inwardly from the inner surface  48  for locating and supporting the spool  26  and friction plate  30 ,  32  within the cavity of the housing  40 .  
         [0021]     A plurality of tabs  64  extends from an edge of the housing  40 . The tabs  64  correspond to a plurality of slots  65  formed in the mounting plate  18 . The tabs  64  have an arrowhead-shaped cross section to guide the tabs into the slots  65  in the mounting plate  18 . The tabs  64  engage or snap against the edges of the mounting plate  18  defining the slots  65  to fixedly secure the housing  40  to the mounting plate  18 . Preferably, the housing  40  includes seven tabs  64  for lockingly engaging as many slots  65  in mounting plate  18 . Most preferably, a pin  67  extends from the edge of the housing  40  to help locate the housing  40  relative to the mounting plate  18  during assembly. The housing  40  is advantageously formed in one piece from any suitable rigid material. In the preferred embodiment, the housing is molded of glass reinforced nylon.  
         [0022]     The mounting plate  18  includes an aperture  60  corresponding with the throughbore  52  in the flat center  50  of the domed portion  46 . The throughbore  52  in the flat center  50  and the aperture  60  in the mounting plate  18  are generally aligned along a longitudinal axis  62 . The throughbore  52  in the flat center  50  rotatably supports the drive nut portion  34  of the torque limiter  28 . The aperture  60  in the mounting plate  40  rotatably supports the shaft  24 .  
         [0023]     It may be necessary to provide an opening in a compartment wall of the vehicle to accommodate the winch assembly  12 . In that case, a cap  66  is fixedly secured to the flat center  50  of the housing  40 . The cap  66  is adapted for sealing the opening to prevent exhaust gases and moisture from entering the vehicle compartment. Preferably, the cap  66  is made from foam material or other flexible materials having similar sealing properties known by those skilled in the art.  
         [0024]     The sheave assembly or spool  26  is shown in detail in  FIGS. 3-5 . The spool  26  is disc-shaped and is preferably formed from plastic in an injection mold. The spool  26  includes opposite first  70  and second  72  sides. A gear ring  74  is integrally molded in the first side  70 . The gear ring  74  includes an inner circumerence that defines a void for receiving a portion of the actuator  38 . A circumferential surface is formed along the inner circumference of the gear ring  74 . More specifically, the ring gear  37  from the gear reduction mechanism  36  described above is defined along the circumferential surface for drivingly engaging the actuator  38 . The gear ring  74  also includes an outer edge. A plurality of projections  76  extends radially outwardly from the outer edge. A plurality of voids  78  are defined between adjacent pairs of projections  76 . During formation of the spool  26 , the gear ring  74  is suspended within a cavity in the mold. Molten plastic is injected into the mold and fills the voids  78  between the projections  76 . The plastic hardens to form a holding portion that fixedly secures the gear ring  74  to the spool  26 .  
         [0025]     A generally cylindrical center  81  defines the bottom of the groove  27 . The center  81  of the spool  26  includes a cut-away portion  83 . A slot  82  extends generally radially inwardly from an outer edge of the second side  72  toward a center of the spool  26 . The slot  82  extends through the groove  27  to accept the end fitting  90  of the cable  16 . The end fitting  90  has a pin  92  which extends axially outwardly from a curved sleeve  94 . The end fitting  90  is inserted into the slot  82  as shown in  FIG. 5 , until the pin  92  rests in the end of the slot  82 . As shown in  FIG. 4 , the pin  92  is pivotally supported and retained at the end of the slot  82  to allow the sleeve  94  to rest against the cut-away portion  83  as the cable  16  is wound about the center  81  of the spool  26 . The cable  16  extends from the sleeve  94  and exits the housing  40  through the slots  53 ,  55  of the flared portion  42   a  and block  49 , as best shown in  FIG. 6 . The sleeve  94  abuts the block  49  to relieve stress on the interconnection between the pin  92  and the edges of the spool  26  defining the slot  82  when the cable  16  has been uncoiled from the spool  26 . Block  49  also prevents winch mechanism from back-winding and provides a bumper to the sleeve from breaking through the wall of the housing. A plurality of apertures  98  are formed radially about the central portion the spool  26  to promote an even cooling of the spool  26  after formation in the injection mold.  
         [0026]     The invention has been described in an illustrative manner. It is, therefore, to be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Thus, within the scope of the appended claims, the invention may be practiced other than as specifically described.