Abstract:
The invention provides a reeling device for a hoisting system, including a flexible member having a lower end and an upper end, a rotatable drum on which the flexible member is windable, disk means rotatably mounted on said drum, to which disk means the upper end of the flexible member is anchored, and a stop mechanism activated by the disk means once the flexible member has completely unreeled from the drum.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a reeling device for use with a hoisting system, in particular, for an underbody hoist system for securing a motor vehicle spare tire against the underside of a motor vehicle body. 
   BACKGROUND OF THE INVENTION 
   Spare tires for vehicles are heavy and bulky objects that, in many vehicles, are accommodated below the vehicle body and are secured against the bottom of the vehicle or against a structure carried by elements of the vehicle chassis. Because of their weight and size, vehicle spare tires can rarely be lowered to the ground, or raised for storage, by hand. For this reason, vehicles with heavier tires are provided with hoisting devices such as winches, by means of which the spare tire is lowered or raised using a steel cable. Upon lowering the spare tire, the cable may reach its fully unwound state. Should the drum continue to be turned in the original sense, the cable would start to wind back on the drum of the hoist in the opposite direction, and the load would be unintentionally raised. It would therefore be advantageous to provide a device that, in the case of a fully unwound cable, would prevent the load from being raised unintentionally. State of the art devices, are relatively complicated to manufacture and comprise many parts. Moreover, the braking action is based on a local tight curve along the cable, eventually causing premature wearing of the cable. Furthermore, in these devices, the brake mechanism is almost entirely located inside the drum, which may lead to functional difficulties. 
   DISCLOSURE OF THE INVENTION 
   It is thus one of the objects of the present invention to overcome the shortcomings of prior art devices and to provide an improved, simpler, less expensive, safer and more practical solution to the above-described problems. 
   The invention therefore provides a reeling device for a hoisting system, comprising a flexible member having a lower end and an upper end; a rotatable drum on which the flexible member is windable; disk means rotatably mounted on the drum, to which disk means the upper end of the flexible member is anchored, and a stop mechanism activated by the disk means once the flexible member has completely unreeled from the drum. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is herein described, by way of example only, with reference to the accompanying drawings. 
     With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. 
     In the Drawings: 
       FIG. 1  is a schematic illustration of a preferred embodiment of the invention, showing the lowering of a load and a flexible member approaching its fully unwound state; 
       FIG. 2  is similar to  FIG. 1 , but showing the flexible member having just reached its fully unwound state; 
       FIG. 3  is similar to  FIG. 2 , with the drum having been rotated a little further, thereby activating the stop mechanism; 
       FIG. 4  is an exploded view of the flexible member drum; 
       FIG. 5  is an exploded view of a section of the device, and 
       FIG. 6  is an exploded view of the entire device. 
   

   DETAILED DESCRIPTION 
   Referring now to the drawings, there is shown in  FIG. 1  a schematic illustration of a preferred embodiment of the invention. Seen is a drum  2  rotatably mounted on pivot  4  and having a flexible member, e.g., a chain or a cable  6  partly wound around it. The upper end of the cable is attached to a disk  8 , rotatably mounted in drum  2  and coupled with the movable latch  10  of a stop mechanism by means of an eccentric pivot  12 . The motion of latch  10  is constrained to a substantially linear motion by means of two projections  14 ,  14 ′ that are affixedly attached to drum  2 . The stationary stop  16  of the stop mechanism is a part of one of the brackets enclosing the device (not shown). 
   Should drum  2  be rotated clockwise around pivot  4 , cable  6  will soon reach the fully unwound state illustrated in FIG.  2 . Further clockwise rotation of the drum  2  will bring the device to the state represented in FIG.  3 .  FIG. 3  shows the device following further clockwise rotation of drum  2  from the state shown in  FIG. 2 , causing cable  6  to change its angle relative to the radius of drum  2  and consequently, to rotate disk  8  relative to the drum. Thereby, the position of eccentric pivot  12  has changed relative to drum  2 , pushing movable latch  10  of the stop mechanism leftward to be intercepted by stop  16 . Thus, further clockwise rotation of drum  2  and consequent unintentional rewinding of cable  6  are prevented. 
   The exploded view of the drum, shown in  FIG. 4 , shows a drum core  18 , of a width determined by the thickness of cable  6 , having peripheral flange  20 , advantageously a one-piece aluminum casting. Disk  8 , having eccentric pivot  12 , is preferably injection molded, with the splayed end of cable  6  inserted into the mold prior to the casting for permanent anchoring. Further shown is an end plate  22 , having stamped-out guide projections  14 ,  14 ′ used to constrain latch  10  to a linear motion. End plate  22  is entirely stamped out from steel sheet, including reinforcement features  24 . Further shown is the cable  6 , having a straight portion and a wound portion  6 ′. Latch  10  is also stamped from steel sheet. Flange  20  is provided with a cylindrical recess  26 , which accommodates one side of disk  8 , and end plate  22  has a circular opening  28  for receiving the other side of disk  8 . Recess  26  and opening  28  serve as bearings for disk  8 . In its assembled form, the drum components are secured together by six rivets  30 , defining between themselves an annular space for a plurality of turns of cable  6 ′ with hub  32  of drum core  18  fitting hole  34 . Pivot  12  projects through opening  28 , thus enabling latch  10  to rotatably couple with it. Latch  10  and pivot  12  are prevented from accidental separation by riveting the tip of pivot  12 . 
   The exploded view of a section of the device of the present invention, shown in  FIG. 5 , depicts in detail assembled drum  2 , pivot  36  around which it revolves, cable  6  and latch  10  of the stop mechanism. Further seen are the stationary stop  16 , main bracket  38  from which stop  16  is stamped out, and some parts of lever  40  and pin  42  of the reduction gear that is used to rotate drum  2 . Another component of the reduction gear is an internal gear  44 , advantageously an integral part of drum  2  (FIG.  5 ). The reduction gear, known as “wobble gear,” comprises an external gear  46  fixedly attached to lever  40  and schematically indicated by a thin line in  FIG. 5 , and seen in its real shape in FIG.  6 . It has less teeth than internal gear  44 , e.g., 12 teeth as compared to the 13 teeth of internal gear  44 . When lever  40  is set wobbling by an eccentric  48  mounted on a shaft  50  ( FIG. 6 ) manually rotatable by means of a crank, lever  40 , restrained by pin  42  seated in the elongated hole  52  (FIG.  5 ), causes external gear  46  to roll off internal gear  44 . Because of the difference in the number of teeth (13 compared to 12), the ratio of reduction will be 13:1. In the assembled state, pin  42  can accommodate the wobbling motion of lever  40  by freely swivelling in holes  58 ,  60  in brackets  38  and  54 , respectively. The entire device is held together by fasteners  56 . 
   It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrated embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.