Patent Publication Number: US-2005133549-A1

Title: Supporting unit for an external spare wheel

Description:
The present invention relates to a supporting unit for an external spare wheel.  
      In general, supporting units of a known type are designed for supporting a spare wheel underneath the floor panel of a motor vehicle and comprise: 
          a box-section bracket anchored to the floor panel;     a bell, which can be fitted to the spare wheel and can be moved with respect to the bracket away from and towards a recovery position, in which the bell is set up against the bracket; and     a cable for transmitting motion, which passes through the bracket and has one end anchored to the bell.        

      Also associated to the supporting units of the type described above is normally a recovery and clamping device, which is set inside the vehicle in a position separate from the box-section bracket, and is connected to a second end of the cable for recovery of the cable itself and for blocking sliding of the cable once the bell has been recovered and set back in its own recovery position.  
      In the supporting units of the type described above, the possible failure of the cable for transmitting motion determines a serious drawback represented by dropping both of the bell and of the spare wheel with consequences that can be quite easily imagined, above all in the case where the vehicle is moving.  
      The purpose of the present invention is to provide a supporting unit for an external spare wheel which will be free from the drawback described above.  
      According to the present invention, a supporting unit for an external spare wheel is provided, said unit being designed to support the spare wheel underneath the floor panel of a motor vehicle and comprising: 
          a box-section bracket anchored to the floor panel;     a bell, which can be fitted to the spare wheel and can be moved with respect to the bracket away from and towards a recovery position, in which the bell is set up against the bracket; and     a cable for transmitting motion, which passes through the bracket and has one first end fixed to the bell and one second end fixed to a device for recovery of the cable itself.        

      The unit is characterized in that it comprises a safety assembly, which is arranged on the inside of the box-section bracket and is set between the first end of the cable for transmitting motion and the bell for securing the bell itself in its recovery position in the event of failure of the cable for transmitting motion. 
    
    
      The invention will now be described with reference to the annexed drawings, which illustrate a non-limiting example of embodiment thereof, and in which:  
       FIG. 1  is a perspective view of a first preferred embodiment of the supporting unit for an external spare wheel made according to the present invention; and  
       FIG. 2  is a cross-sectional view of the supporting unit of  FIG. 1 . 
    
    
      With reference to  FIGS. 1 and 2 , the reference number  1  designates, as a whole, a supporting unit for an external spare wheel, schematically illustrated with a dashed line and designated by the reference number  2 .  
      The unit  1  is designed for supporting the spare wheel  2  underneath the floor panel  3  of a motor vehicle, and comprises a box-section bracket  4  anchored to the floor panel  3  and a bell  5 , which can be fitted to the spare wheel  2  and can be moved with respect to the bracket  4  away from and towards a recovery position, in which the bell  5  is set up against the bracket  4  to clamp the wheel  2  up against the floor panel  3 .  
      The unit  1  further comprises a cable  6  for transmitting motion, which passes through the bracket  4  and has one end  7  fixed to the bell  5  and one end  8  fixed to a recovery device (known and not illustrated) of the cable  6  itself.  
      The box-section bracket  4  comprises a substantially parallelepipedal anchoring base  11  and a vertical tubular body  12 , which is set transverse to the base  11  and extends from the base  11  on the opposite side of the floor panel  3  with respect to the base  11  along a vertical axis A. In particular, the base  11  is defined by two cup-like half-shells  13  assembled together and has a front hole  14  and a coupling socket  15 , which is fixed to a bottom wall  16  of the base  11  itself and shares the axis A.  
      The body  12  extends from the wall  16  along the axis A and comprises a cylindrical wall  17 , which is fitted inside the coupling socket  15  and has a bottom circular portion  18  facing the bell  5 . The body  12  further comprises a bottom mouth portion  19  defined by a cylindrical portion  20 , which is coupled inside the wall  17  through the opening  18  and defines a shoulder  21  inside the wall  17 , and a portion  22  of a substantially conical shape flared out downwards and fixed to the portion  20 .  
      The body  12  further comprises three half-sheared portions  23 , which are set upstream of the shoulder  21  along the axis A and are obtained by partial shearing of the wall  17  to extend radially towards the inside of the body  12 . The three half-sheared portions  23  are uniformly distributed around the axis A, and each one has a respective top surface  24  inclined downwards and a respective side surface  25  facing the axis A and defining with the corresponding surface  24  a corresponding sharp edge  26 .  
      The unit  1  further comprises a safety assembly  35 , which is set inside the tubular body  12  and is set between the end  7  of the cable  6  and the bell  5  to secure the bell  5  in its recovery position in the event of failure of the cable  6 .  
      The assembly  35  comprises a tubular sheath  36 , which is fixed to the bell  5  and is set so that it can slide inside the body  12  along the axis A with an outer cylindrical surface  37  thereof skimming both the sharp edges  26  of the half-sheared portions  23  and an internal surface  20   s  of the portion  20 .  
      The sheath  36  is delimited at the top by an annular surface  38 , which is transverse to the axis A, constitutes a resting surface for a washer  42 , and has an internal compartment  39  closed at the top by a plug  40  and at the bottom by a plug  41 . In particular, the plug  40  is rigidly constrained to the sheath  36  and has a through hole  43  and a contrast surface  44  transverse to the axis A and facing the inside of the compartment  39 . The plug  41 , which is set at the opposite end of the sheath  36  with respect to the plug  40 , is connected to the bell  5  and is rigidly connected to the sheath  36  by means of three hemi-spherical embossings  45  inserted inside the plug  41  and obtained by deformation of the sheath  36  itself.  
      The assembly  35  further comprises three blocking balls  46 , which are radially mobile through respective conical windows  47  made through the sheath  36  and uniformly distributed around the axis A, and an extractor device  48 , which is connected to the cable  6  and is set inside the sheath  36  for extracting the balls  46  from the sheath  36  itself, pushing them up against the body  12 .  
      The device  48  comprises a clamping terminal  49 , anchored to the end  7  of the cable  6  for transmitting motion, and a spring  50 , which is set between the terminal  49  itself and the surface  44  of the plug  40  and is designed to be compressed by the terminal  49  and the surface  44  themselves either as a result of the action of the weight of the wheel  2  or, in the absence of the wheel  2  and with the bell  5  in its recovery position, as a result of the elastic action of expansion of a spring  51  compressed between the washer  42  and the wall  16  and set along the axis A.  
      In particular, the terminal  49  comprises: a step-like portion  52 , which is inserted so that it can slide axially through the hole  43  and is fixed to the end  7 ; a shoulder  53 , which has an external diameter substantially equal to an internal diameter of the compartment  37  and is fixed to the portion  52 ; and a cylindrical end portion  54 , which is set axially on the opposite side of the portion  52  with respect to the shoulder  53  and axially faces the plug  41 .  
      The step-shaped portion  52  has a hollow body  55 , inside which there is inserted and clamped the end  7  of the cable  6 , and a full cylindrical body  56 , which has an external diameter larger than the internal diameter of the hole  43  and is set bearing upon the surface  44  so as to bring about maximum compression of the spring  50 .  
      The spring  50  is axially compressed along the axis A between the shoulder  53  and the plug  40  and is designed to expand in the event of failure of the cable  6 , thus causing axial sliding of the terminal  49  inside the compartment  37  and in the direction of the plug  41 .  
      The device  48  further comprises an annular containment seat  57  made around the portion  54  for partially containing the balls  46 , and an annular thrust ramp  58  made on the outside of the portion  54  in a position that is axially contiguous to and in communication with the annular seat  57  for pushing the balls  46  partially outside of the windows  47  themselves during axial sliding of the terminal  49 .  
      The balls  46  are arranged in a resting position thereof both inside the seat  57  and inside the corresponding windows  47 , the conical conformation of which is such as to prevent the balls  46  from coming out completely and such as to enable the balls  46  to come out only partially.  
      The ramp  58  is connected to the seat  57  and has a substantially conical shape, with an outer diameter which increases progressively along the axis A and in the direction of the shoulder  53  with respect to the bottom diameter of the seat  57  to force the balls  46  to protrude progressively outside of the corresponding windows  47  during expansion of the spring  50  and to block the balls  46  themselves in a respective safety position, in which the balls  46  can impact against the shoulder  20 , so blocking any further axial sliding of the sheath  36  and hence preventing the bell  5  from moving away from the recovery position.  
      In use, the balls  46  arranged in their resting position can freely partially face outside of the corresponding windows  47  and are pushed back by the surfaces  24 ,  25  inside the windows  47  during the voluntary operations of moving of the bell  5  and of axial sliding of the sheath  36  inside the body  12 .  
      At the moment when the cable  6  were to break in any point between the two ends  6  and  7 , the spring  50  would be axially released and could expand, causing sliding of the terminal  49  inside the sheath  36  and, as previously described, engagement of the ramp  58  with the balls  46  as well as blocking of the balls  46  in the corresponding safety position, in which they would impact against the shoulder  52 , blocking any further sliding of the terminal  41  and, hence, also of the bell  5 .  
      Since, in the absence of the wheel  2  on the bell  5 , the spring  50  would extend, with consequent blocking of the balls  46  in their safety position during recovery of the cable  6 , the sheath  36 , which has been inserted inside the body  12 , initially comes to impinge upon the washer  42 , which is set resting on the half-sheared portions  23  and consequently compresses the spring  51 , so causing compression also of the spring  50  since the spring  51  prevents axial advance of the sheath  36  in favour of the axial advance of the terminal  49 .  
      It is understood that the invention is not limited to the embodiment described and illustrated herein, which is to be considered merely as an example of embodiment of the supporting unit for an external spare wheel, it being instead possible for said supporting unit to undergo further modifications regarding shapes and arrangement of parts, and constructional and assembly details.