Abstract:
A tire carrier assembly is operative to provide a controlled payout of cable in response to an application of a minimum predetermined amount of force upon the tire carrier assembly. The tire carrier assembly includes a housing having a bottom wall and a side wall extending outwardly from the bottom wall defining an interior space. A rotation shaft is coupled to the housing and having a longitudinal axis. A sheave is coupled to the shaft and rotatable about the longitudinal axis. A gear member extends from the sheave and is rotatable therewith about the longitudinal axis. A pin fixedly secured to the housing. A torque plate has a gear portion epicyclically engaged with the gear member of the sheave. The torque plate has an arm portion extending generally radially outwardly with respect to the gear portion. The torque plate has a closed-ended slot formed in the arm portion and receiving the pin therethrough. The arm portion has legs extending along opposite sides of the slot. At least one of the legs has a weakened area at which the arm portion deforms in response to an application of a predetermined amount of force upon the tire carrier assembly and contacts an inner surface of the housing to provide a controlled payout of a cable from the sheave.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 11/216,428 filed on Aug. 31, 2005 and Ser. No. 60/606,443 filed Aug. 31, 2004, the contents of which are incorporated herein by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to spare tire carriers, and more particularly to spare tire carriers having overload protection. 
       BACKGROUND 
       [0003]    Various spare tire carriers have been utilized in the past and are well known in the art. Typically, spare tire carriers are designed to hold a spare wheel below the body frame of a vehicle. Generally, the spare tire carrier includes a cable associated with a winch or drive mechanism to raise and lower the tire when needed. Various U.S. Pat. Nos. 4,059,197; 4,535,973; 4,600,352; 4,625,947; 5,251,877; 5,265,708 and 5,415,377 are related to spare tire carrier designs. 
         [0004]    However, none of these prior art designs teach or suggest a spare tire carrier having overload protection with a controlled cable payout. Specifically, there is a need in the art for a spare tire carrier wherein a cable is released allowing the tire to separate from the tire carrier mechanism at a predetermined load; thereby allowing the cable to unwind from a spool such that the cable is prevented from being exposed to high loading forces. Additionally, there is a need in the art for a controlled cable payout in which the rate of the release of the cable can be controlled to avoid a rapid uncontrolled movement of a spare tire 
       SUMMARY OF THE INVENTION 
       [0005]    According to one aspect of the invention, a tire carrier assembly is operative to provide a controlled payout of cable in response to an application of a minimum predetermined amount of force upon the tire carrier assembly. The tire carrier assembly includes a housing having a bottom wall and a side wall extending outwardly from the bottom wall defining an interior space. A rotation shaft is coupled to the housing and having a longitudinal axis. A sheave is coupled to the shaft and rotatable about the longitudinal axis. A gear member extends from the sheave and is rotatable therewith. A pin fixedly secured to the housing. A torque plate has a gear portion epicyclically engaged with the gear member of the sheave. The torque plate has an arm portion extending generally radially outwardly with respect to the gear portion. The torque plate has a closed-ended slot formed in the arm portion and receiving the pin therethrough. The arm portion has legs extending along opposite sides of the slot. At least one of the legs has a weakened area at which the arm portion deforms in response to an application of a predetermined amount of force, which allows the torque plate to rotate about the longitudinal axis and contact an inner surface of the housing to provide a controlled payout of a cable from the sheave. 
         [0006]    According to another aspect of the invention, a tire carrier assembly includes a sheave, a cable, and a torque plate. The sheave is rotatable about a rotational axis. The cable has an end coupled to the sheave for winding thereabout or payout therefrom during corresponding rotation of the sheave about the rotational axis. The torque plate is coupled to the sheave by a gear arrangement and movable generally epicyclically with respect to the sheave during winding and payout of the cable from the sheave. The tire carrier assembly further includes a force-responsive component operatively coupled to the torque plate and having a first state in which the torque plate is limited to the generally epicyclical movement during the winding and payout of the cable from the sheave. The force-responsive component further includes a second state in which the force-responsive component is deformed and allows the torque plate to rotate about the rotational axis in a non-epicyclical manner and to contact an adjacent component within the tire carrier assembly so as to control payout of the cable from the sheave, wherein the second state is initiated by an application of a threshold amount of force upon the tire carrier assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an exploded perspective view of a tire carrier assembly according to the invention; 
           [0008]      FIG. 2  is a partial front view of the housing, torque plate and rivet of the tire carrier assembly, according to one embodiment of the invention, wherein the rivet is a frangible component; 
           [0009]      FIG. 3  is a plan view of the housing, torque plate and rivet of the tire carrier assembly according to an alternate embodiment of the invention; 
           [0010]      FIG. 4  is a perspective view of the torque plate according to an alternate embodiment of the invention; 
           [0011]      FIG. 5  is a plan view of the a torque plate and a first version of the housing, according to an alternative embodiment of the invention; 
           [0012]      FIG. 6  is a perspective view of a torque plate and a second version of the housing, according to an alternate embodiment of the invention; 
           [0013]      FIG. 7  is a perspective view of a torque plate and a third version of the housing, according to an alternate embodiment of the invention; 
           [0014]      FIG. 8  is a plan view of a housing, torque plate, rivet and cable guide according to an alternative embodiment of the invention, wherein the cable guide is a frangible component; 
           [0015]      FIG. 9  is a perspective view of the cable guide in  FIG. 8 ; 
           [0016]      FIG. 10  is a top view of a torque plate according to an alternate embodiment of the invention 
           [0017]      FIG. 11  is a side view of the torque plate of  FIG. 10 ; 
           [0018]      FIG. 12  is a plan view of the tire carrier assembly utilizing the torque plate of  FIG. 10 , according to an alternate embodiment of the invention; and 
           [0019]      FIG. 13  is a top view of a torque plate according to an alternate embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    The present invention provides a tire carrier assembly that supports a tire on a cable and allows for winding and payout of the cable from a sheave to raise and lower the tire, respectively, relative to the tire carrier assembly. Described in greater detail below, the tire carrier assembly includes a force-responsive component that, on one hand, allows for normal winding and payout of the cable for raising and lowering the tire, and, on the other band, allows for a controlled payout of the cable from the sheave in the event of an unplanned application of force externally upon the tire carrier assembly. 
         [0021]    Referring to  FIG. 1 , a tire carrier assembly according to the invention is generally indicated at  10 . The tire carrier assembly  10  includes a rotation shaft  15 , a housing  20 , a torque plate  25 , an eccentric bushing  30 , a cable guide  35 , a sheave  75  and a cover plate  40 . 
         [0022]    The housing  20  includes a bottom wall  22  having a first aperture  24  formed therein receiving the shaft  15 . The housing  20  also includes a sidewall  26  that extends upward from the bottom wall  22  and defines an interior space  28  of the housing  20 . The sidewall  26  includes opposite inner  27  and outer  29  surfaces. As will be described in more detail below, an arm portion  70  of the torque plate  25  contacts the inner surface of the housing  20  after a force-responsive component of the tire carrier assembly  10  deforms or breaks in response to an application of a predetermined amount of force upon the tire carrier assembly  10 . 
         [0023]    The sheave  75  is disposed within the interior space  28  of the housing  20 . The sheave  75  includes a second aperture  76  that receives the shaft  15  therethrough. The sheave  75  also includes a gear member  80  associated therewith. In one aspect of the invention, the gear member  80  is insert molded to bond the gear member  80  on an inner portion of the sheave  75 . The gear member  80  is generally coaxial with the shaft  15 . 
         [0024]    The torque plate  25  is positioned adjacent the sheave  75 . The torque plate  25  includes a base  85  having opposing first  87  and second  89  surfaces. The torque plate  25  has a third aperture  90  formed therein that receives the shaft  15  therethrough. A gear portion  95  extends from the torque plate  25  generally aligned with the third aperture  90  and is adapted to epicyclically engage the gear member  80  of the sheave  75 . The torque plate  25  also includes an arm portion  70  that projects radially from the base  85 . 
         [0025]    The eccentric bushing  30  is positioned adjacent the torque plate  25 . The bushing  30  has opposing first  100  and second  105  surfaces generally extending between an integrally formed bounding wall  110 . The bushing  30  includes a fourth aperture  115  that receives the shaft  15  therethrough. The first surface  100  of The bushing  30  includes a cam  120  formed thereon. The cam  120  is positioned within the third aperture  90  of the torque plate  25 . 
         [0026]    The cable guide  35  is positioned within the internal space  28  of the housing  20  and is located radially outboard relative to the sheave  75  for positioning a cable about the sheave  75 . The cable guide  35  includes a lobe  125  extending therefrom for contacting the cable to ensure proper winding of the cable about the sheave  75 . 
         [0027]    The cover plate  40  is disposed adjacent the eccentric bushing  30 . The cover plate  40  includes a fifth aperture  130  formed therein that receives the shaft  15  therethrough. The cover plate  40  is attached to the housing  20  utilizing rivets  135  or other fasteners suitable for such a connection. The cover plate  40  may include location ledges  140  formed thereon to provide location features when mounting the cover plate  40  to a vehicle. 
         [0028]    In one embodiment of the tire carrier assembly  10 , a longitudinally extending slot or notch  150  is formed in the arm portion  70  of the torque plate  25 . The notch  150  is open ended and extends transversely between spaced apart forward  155  and trailing  160  legs of the arm portion  70 . As best shown in  FIG. 3 , a pin or rivet  135  is supported by the housing  20  and the cover plate  40 , such that the rivet  135  extends through the notch  150  formed in the arm portion  70 . In this embodiment of the tire carrier assembly  10 , the rivet  135  is the frangible component. 
         [0029]    As stated above, the tire carrier assembly  10  of the invention includes a frangible component that breaks upon application of a predetermined force, allowing the torque plate  25  to rotate about the shaft  15 , such that the arm portion  70  of the torque plate  25  engages the inner surface  27  of the sidewall  26  of the housing  20  and allows a controlled payout of cable wound about the sheave  75 . 
         [0030]    Referring to  FIG. 2 , an embodiment of the tire carrier assembly  10  is shown, wherein the rivet  135  is the frangible component. The rivet  135  includes generally concentric first  136  and second  138  sections, wherein the first section  136  has a larger diameter than the second section  138 . The first  136  and second  138  sections are separated by a transition plane  139 . In one aspect, the transition plane  139  of the rivet  135  is substantially aligned with the second surface  89  of the base  85  of the torque plate  25 , defining a shear plane, such that when a predetermined force is applied to the tire carrier assembly  10 , the torque plate  25  breaks the rivet  135  along the shear plane. In this embodiment of the invention, the cover plate  40  may include a depression  165  formed about the rivet  135  that is received within the notch  150  of the arm portion  70  of the torque plate  25 . In this manner, one may align the transition plane  139  of the rivet  135  with the second surface  89  of the base  85  of the torque plate  25  to ensure a clean shear of the rivet  135 , as opposed to bending of the rivet  135 . 
         [0031]    After the rivet  135  has been sheared, the torque plate  25  can rotate about the shaft  15 , as it is no longer constrained by the rivet  135  positioned within the notch  150 . As the torque plate  25  rotates, the arm portion  70  contacts the inner surface  27  and/or bottom surface  47  of the housing  20 . This contact between the arm portion  70  of the torque plate  25  and the inner surface  27  and/or bottom surface  47  of the housing  20  provides a controllable frictional resistance which, due to the operable engagement between the gear portion  95  of the torque plate  25  and the gear member  80  associated with the sheave  75 , controls the rate of payout of cable from the sheave  75 . 
         [0032]    Referring to  FIGS. 3 and 4 , another embodiment of the tire carrier assembly  10  is shown, wherein the trailing leg  160  of the arm portion  70  of the torque plate  25  is the frangible component, as opposed to the rivet  135  or cable guide  35  of the previous embodiments. In this embodiment, the rivet  135  does not include the first and second concentric sections  136 ,  138 , but is rather designed to withstand the shear forces applied to it by the torque plate  25 . The arm portion  70  of the torque plate  25  in this embodiment includes the forward  155  and trailing  160  legs separated by the notch  150 , as described above. The trailing leg  160  of the arm portion  70  contacts the rivet  135  and breaks away from the torque plate  25  when a predetermined force is applied to the tire carrier assembly  10 . The torque plate  25  may include a weakened portion  170 , at which at least a portion of the trailing leg  160  can break away when the predetermined force is applied to the tire carrier assembly  10 . The weakened portion  170  may be a scored or engraved area, a hole or any similar feature that weakens the arm portion  70  sufficiently to achieve the desired deformation in response to the predetermined force. As described above, once the trailing leg  160  of the torque plate  25  is deformed or sheared, the torque plate  25  can rotate about the shaft  15 , such that the forward leg  155  of the torque plate  25  contacts the inner surface  27  and/or bottom surface  47  of the housing  20 . 
         [0033]    Referring to  FIG. 5 , a first version of the housing  20  is shown, wherein at least a portion of the inner surface  27  has a curved profile  32  and the inner surface  27  of the sidewall  26  includes a ledge  45  extending inwardly therefrom. The ledge  45  includes a bottom surface  47 , which is shown illustratively as being generally planar. Other configurations of the bottom surface, however, may be utilized, as will be discussed further below. 
         [0034]    Referring to  FIG. 6 , a second version of the housing  20  is shown. As with the first version of the housing  20 , the inner surface  27  of the sidewall  26  includes a curved profile  32  and an inwardly extending ledge  45 . However, in the second version of the housing  20  shown in  FIG. 7 , the bottom surface  47  of the ledge  45  includes first and second sections  50 ,  55 . The first section  50  includes an upward incline with the second section  55  having a relatively planar configuration. The first section  50  is preferably positioned above and separated from the second section  55  by a step  60 . 
         [0035]    Referring to  FIG. 7 , a third version of the housing  20  is shown. The third version of the housing  20 , as with the first and second versions, includes an inner surface  27  of a sidewall  26  having a curved profile  32 , as well as an inwardly extending ledge  45  formed on the sidewall  26 . The third version of the housing  20  further includes a series of lobes or bumps  65  formed on the inner surface  27  of the sidewall  26 . The rate at which cable is paid out can be controlled by changing the curvature of the inner surface  27  of the housing  20 , as well as the shape and thickness of the lobes  65  formed on the inner surface  27  of the housing  20 . Additionally, the rate can be controlled by adjusting the size and steepness of the first section  50  of the bottom surface  47  of the ledge  45  which varies the frictional resistance applied to the torque plate  25 . In this manner, various tire carrier assemblies  10  for different vehicles can be tuned to adjust the payout of cable to a specific level associated with a tire of that vehicle. 
         [0036]    As can be seen in all three versions of the housing  20 , the curved profile  32  terminates at a sharp angle  34 . The sharp angle  34  provides a stop for engaging the arm portion  70  of the torque plate  25  when the torque plate  25  is allowed to rotate about the shaft  15  after breaking of the frangible component. 
         [0037]    Referring to  FIGS. 8 and 9 , an alternative embodiment of the tire carrier assembly  10  is shown, wherein the lobe  125  formed on the cable guide  35  is the frangible component. In this embodiment, the arm portion  70  of the torque plate  25  does not include a longitudinally extending notch  150 , as in the previously described embodiments. The rivet  135  passes through the cover plate  40 , but does not contact the torque plate  25  and is not positioned within the notch  150 . Rather, the arm portion  70  of the torque plate  25  includes a single lobe  180  ( FIG. 8 ) that is free to rotate and contacts a lobe  125  formed on the cable guide  35  preventing rotation of the torque plate  25 . The cable guide  35  may include a weakened zone or break point  172  ( FIG. 9 ) at which the lobe  125  shears after application of the predetermined force to the tire carrier assembly  10 . Breaking the lobe  125  allows for rotation of the torque plate  25  about the shaft  15  and subsequent contact between the arm portion  70  and the inner surface  27  of the housing  20 , as earlier described. 
         [0038]    As shown in  FIG. 1 , the tire carrier assembly  10  of the invention may further include optional components, such as an anti-rotation member  190  that is positioned on the cable guide  35  and intersects with notches  195  formed on the integrally formed bounding wall  110  of the bushing  30  once the cable has completely paid out from the sheave  75 . The anti-rotation member  190  prevents the cable from back winding upon the sheave  75  after it has been released. 
         [0039]    Additionally, the tire carrier assembly  10  of the invention may include a clutch plate  200  that is adapted to releasably engage the bushing  30  and allow slip if an excessive force is applied to the rotation shaft  20 . More specifically, the clutch plate  200  includes front and rear surfaces  205 ,  210  and a central aperture  215 . The front surface  205  includes raised areas  220  formed about a peripheral edge that mates with detents  225  formed on the eccentric bushing  30 . This design allows the clutch plate  200  to slip where a sufficient torque is applied to release the raised areas  220  from the detents  225 . 
         [0040]    Referring to  FIGS. 10-11 , another embodiment of the tire carrier assembly  10 ′ is shown, wherein the arm portion  70 ′ of the torque plate  25 ′ includes a connecting wall  162  that extends between and connects the distal ends  156 ′,  162 ′ of the forward  155 ′ and trailing  160 ′ legs. As shown in the illustrated embodiment, the connecting wall  162 ′ is integrally formed with the forward  155 ′ and trailing  160 ′ legs. By this arrangement, the notch  150 ′ is close ended unlike the previously described embodiments. Additionally, a weakened portion  170 ′ is provided on the arm portion  70 ′ of the torque plate  25 ′ so that the trailing leg  160 ′ is the frangible component. Illustratively, the weakened portion  170 ′ is a hole formed in arm portion  70 ′ adjacent the trailing leg  160 ′. The connecting wall  162  resists the deformation of the trailing leg  160 ′ in response to the application of the predetermined amount of force upon the tire carrier assembly and thereby provides a generally consistent range of deformation of the arm portion  70 ′ irrespective of the location of the pin  135 ′ within the slot. 
         [0041]    Referring to  FIG. 13 , an alternate embodiment of the torque plate  25 ″ is shown, wherein the trailing leg  160 ″ is the frangible component due to the trailing leg  160 ″ being smaller in size than the leading leg  155 ″. More specifically, an outer edge  161  of the leading leg  155 ″ is generally tangential with the circular-shaped base  85 ″ of the torque plate  25 ″ such that the leading leg  155 ″ is substantially triangular shaped. The outer edge  163  of the trailing leg  160 ″, on the other hand, is generally parallel with the notch  150 ″ such that the trailing leg  160 ″ is substantially rectangular or beam-shaped. The outer edge  163  of the trailing leg  160 ″intersects with a tangential edge  165  and forms a weakened portion in the form of a corner  167 . 
         [0042]    In another embodiment of the invention, the torque plates described herein may be formed of a powder metal. Powder metals are more brittle than conventional steel. As a result, a torque plate made from a powder metal will have high load capacity, but will also fracture more predictably or controllably along the weakened portions described above. 
         [0043]    The invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than limitation. Many modifications and variations of the invention are possible in light of the above teachings. For example, any of the aforementioned embodiments of the tire carrier assembly can be used with any of the versions of the housing described above. Further, the tire carrier assembly may utilize a combination of the frangible components described above. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.