Abstract:
A motorized gearbox having a drive shaft is provided. The motorized gearbox provides input power to rotate the drive shaft. The drive shaft is inserted into a jack housing. Rotation of the drive shaft raises or lowers the jack housing. The integrated drive shaft is capable of replacing a hand crank and an input shaft of a mechanically operated jack to convert the mechanically operated jack to a motorized jack.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority from U.S. Provisional Patent Application No. 60/763,703, filed on Jan. 31, 2006, and titled POWERED DRIVE FOR JACK, which is hereby incorporated in its entirety by reference. 
     
    
     FIELD OF ART  
       [0002]     This invention relates generally to mechanical jacks, and more particularly, to a powered drive for a mechanical jack.  
       BACKGROUND OF THE INVENTION  
       [0003]     Many mechanical jacks used in the automotive and trailer industries are operated by hand. Thus, the application of human strength is required to rotate the jack handle to raise and lower the jack. However, there are numerous instances where it is inconvenient, difficult, or impossible to operate the jack by hand. Therefore, there are numerous occasions where motorized operation of the jack is desired. In addition, a motorized jack is especially desirable in the retail sector, such as, through the modification of an existing manual jack with a replacement, after-market, powered drive component.  
         [0004]     In addition, mechanical cranking and a great amount of physical exertion is required in order to quickly provide a significant amount of jack elongation or contraction of the jack. Accordingly, it is often desirable to incorporate a drop leg to eliminate or at least reduce mechanical cranking required in order to provide significant elongation or contraction in a short amount of time, such as at the beginning or completion of the lifting process.  
         [0005]     As is known in the art, when an after-market modification is made to a jack to include an after-market motor, the motor is mounted to the jack so that the original driving shaft of the jack is aligned with the gearbox of the motor. Such a modification requires coupling the motor to the jack and to the jack shaft. However, any misalignment of the motor and the shaft or the motor and the jack can result in the misapplication of torque to the jack shaft. Frequently, misalignment causes excessive wear of parts, the loss of power from the motor, or damage to the motor and components of the jack.  
         [0006]     It would be advantageous to resolve such alignment issues in the after-market applications so that the problems associated with misalignment are eliminated. Further, an assembled motorized jack is desirable, especially in the retail market. As such, providing an integral motor and shaft either originally or in an after-market replacement component obviates alignment issues problematic in the industry.  
       SUMMARY OF INVENTION  
       [0007]     The present invention provides a powered drive for a jack. The powered drive comprises a motorized gearbox having an integral drive shaft for attachment to the jack. The motorized gearbox provides input power to rotate the drive shaft and, in turn, to raise or lower an outer tube of the jack. A cover is provided for enclosing the powered drive to prevent damage to the powered drive. The jack has a torque stop that is positionable between the cover and the outer jack tube to dampen vibrations from the motor. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The drawings illustrate the best mode presently contemplated for carrying out the invention. In the drawings:  
         [0009]      FIG. 1  illustrates a jack having a motorized gearbox in an embodiment of the present invention;  
         [0010]      FIG. 2 a  is a magnified and interior view of the relevant portion of the jack of  FIG. 1 ;  
         [0011]      FIG. 3  is a chart showing current draw versus load for the present invention as compared to competitive products by Equalizer and Lunde.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]     It should be clear that the invention described herein could be utilized with any type of jack (e.g. with or without drop legs, one or more gear ratios, etc.). Nevertheless, the embodiment described herein is described with reference to the after-market modification of a single-speed jack to replace the actuator and drive shaft with an integral powered drive and drive shaft. The jack of the present invention may, however, be manufactured with the integral powered drive and drive shaft.  
         [0013]     Referring to  FIG. 1 , a jack  10 , in the embodiment shown, is generally a single-speed mechanical jack incorporating a drop leg  11  or “through the air” leg. The drop leg  11  can be used, for example, to quickly lower the drop leg  11  to the ground. The jack  10  can be used with any object that needs to be raised or lowered, including but not limited to, horse trailers, livestock trailers, large flatbed trailers, and construction equipment trailers. The jack  10  has been modified according to an embodiment of the invention so as to replace the input shaft and handle of a manually operated jack with the powered drive  12  and integral drive shaft  14 . Alternatively, the jack  10  may be manufactured with the powered drive  12  and the integral drive shaft  14 .  
         [0014]     The jack  10  has an outer jack tube  16  telescopically movable with respect to an inner jack tube  18 . The drop leg  11  telescopically moves with respect to the jack tubes  16 ,  18  from a raised position to a lowered position. At the lowered position, the drop leg  11  extends from the inner jack tube  18  to contact, for example, the ground. In an embodiment, the drop leg  11  telescopically moves into the inner jack tube  18  to the raised position. The powered drive  12  rotates the drive shaft  14  to raise the outer jack tube  16  with respect to the inner jack tube  18 .  
         [0015]     As best shown in  FIG. 2 , the jack  10  includes the outer jack tube  16  and the inner jack tube  18  driven by a rotating drive screw  20 . The drive screw  20  is coupled to driven gear  22  that engages a drive gear  24  so as to receive input torque. In a preferred embodiment, the driven gear  22  and the drive gear  24  are bevel gears that meshingly engage to drive the drive screw  20 .  
         [0016]     Torque input from the drive shaft  14  rotates the drive gear  24  and engages the driven gear  22 . In an embodiment as shown in  FIG. 2 , the horizontal rotation of the drive shaft  14  is translated into vertical movement of the inner jack tube  18 . The drive screw  20  is coupled to the driven gear  22  to translate torque into telescopic movement of the inner jack tube  18 .  
         [0017]     A motor  26  inputs power into a gearbox  28 . In a preferred embodiment, the motor  26  is an electric motor. Power from the motor  26  is transmitted through the gearbox  28  to the drive shaft  14  so as to rotate the drive shaft  14 . In a preferred embodiment, the motor  26  and the gearbox  28  are an integrated motorized gearbox. As such, when connecting the integral drive shaft  14  and powered drive  12  to a previously manually operated jack, no secondary coupling and alignment issues are created. As described above, attempting to connect an external motor and gearbox to the original jack drive shaft as is presently performed in the industry creates such coupling and alignment issues.  
         [0018]     The drive shaft  14  is integrally formed with the gearbox  28 . The drive shaft  14  extends from the gearbox  28  through the outer jack tube  16 . The drive gear  24  connects to the drive shaft  14  such that rotation of the drive shaft  14  imparts rotation of the drive gear  24 . The gearbox  28  rotates the drive shaft  14  by, for example, frictionally gripping the drive shaft  14 . In a preferred embodiment, the drive shaft  14  has a hex end  34  that engages a female hex output  29  of the gearbox  28 .  
         [0019]     The motor  26  and the gearbox  28  have a cover  30  to, for example, prevent damage and debris from damaging the powered drive  12 . The cover  30  may be a two-sided protective cover for the powered drive  12 . In an embodiment, the cover  30  is secured to the outer jack tube  16  to house the motor  26  and the gearbox  28 .  
         [0020]     When modifying a manually actuated jack to be equipped with the powered drive  12 , the handle and drive shaft of the manually actuated jack are removed. The integral drive shaft  14  of the powered drive  12  is inserted into the jack  10 . For example, the integral drive shaft  14  is inserted through a side of the outer jack tube  16  through the drive gear  24  and out an opposing side of the outer jack tube  16 . The powered drive  12  can then be mounted to the jack  10  according to known methods in the industry.  
         [0021]     As shown in  FIG. 2 , the powered drive  12  has a torque stop  32  that is mounted between the upper jack tube  16  and the powered drive  12  so as to absorb motor start-up and stall energy. In a preferred embodiment, the torque stop  32  is made of a vibration damping material. For example, the torque stop may be a rubber stop to absorb start-up and stall energy from the motor  26 . The torque stop  32  may be positioned on the outer tube  16  and adjacent to the cover  30 .  
         [0022]     Further, current modifications to manually operated jacks comprise large gearboxes and motors that can be cumbersome to install and require significant space. As shown in the embodiment of the invention of  FIG. 2 , the gearbox  28  is sized to fit within the profile of the jack  10  to preserve space and assist in the installation of the powered drive  12 . In addition, the powered drive  12  as disclosed herein provides more torque, greater lifting capacity, and does so at about half the current draw as other competitive products, as shown in  FIG. 3 .  
         [0023]     In anticipation of using the powered jack for a dual jack application, the interior end of the drive shaft  14  has a hex end  34  that is connectable to an extension pipe and/or a second drive shaft (not shown). The extension pipe may have a hex cavity at one end that slides over the hex end  34  of the drive shaft  14  and is coupled to a drive shaft of the second jack at the other end. As a result, the present invention allows for easy coupling to a second jack without use of pins or bolts. In addition, coupling to a second jack does not require an exact length of pipe, the hex shaft is self-fixturing. The gearbox  28  may then drive the second drive shaft to raise or lower a second jack tube.  
         [0024]     In an embodiment of the present invention, a kit may be provided for converting a manually operated jack to a powered drive jack of the present invention. The kit may comprise the powered drive  12  having the integral drive shaft  14 . In addition, the kit may have the cover  30  and the torque stop  32 . To convert a manually operated jack to a powered drive jack of the present invention, an input shaft and a handle of a manually operated jack are removed. The gearbox  28  having the integral drive shaft  14  is inserted into the outer jack tube  16  and through the drive gear  24 . The drive shaft  24  may be inserted through an opposing side of the outer jack tube  16 . The gearbox  28  may then be secured to the jack  10 .  
         [0025]     The kit may have an extension pipe that is attachable to the hex end  34  of the drive shaft  14 . The extension pipe is connectable to an input shaft (or drive shaft) of a second jack for raising or lowering a jack tube of the second jack. The torque stop  32  may be positioned on the outer jack tube  16 . In an embodiment, the torque stop  32  is attached to the gearbox  28 . The cover  30  may be secured such that the torque stop  32  is located between the outer jack tube  16  and the cover  30 .  
         [0026]     Exemplary embodiments of the present invention have been described above and illustrated in the figures. Modifications and alternations will occur to others upon a reading and understanding of this specification. The claims as follow are intended to include all modifications and alterations insofar as they come within the scope of the claims or the equivalent thereof.