Gate screw backup system
BACKGROUND OF THE INVENTION 
     Race car transport trailers typically employ dual rotatable screws to raise and lower the rear gate or door of the trailer. The gate is raised and lowered, or moved between open and closed positions, by an electric motor, which has a drive shaft connected to the screws with appropriate linkage arms and gear boxes. The gate is capable of lifting a race car upwardly for storage upon a raised platform within the body of the trailer. If the motor fails, the gate cannot be moved, and the race car cannot be moved into or out of the trailer. Such failure of the motor presents drastic problems for the race car drivers and owners, who have been known to rip the gate from the trailer so that the car can be removed in time for a race. The time delays and expenses associated with motor failure are undesirable. 
     Therefore, a primary objective of the present invention is the provision of a backup system for the rear gate screw of a transport trailer gate. 
     Another objective of the present invention is the provision of a means and method for rotating a motor drive shaft when the motor is inoperative so that a gate can be raised and lowered. 
     Another objective of the present invention is the provision of a gate screw backup system which is quick and easy to operate, durable in use, and economical to manufacture. 
     These and other objectives will become apparent from the following description of the invention. 
     SUMMARY OF THE INVENTION 
     The gate screw backup system of the present invention includes a first shaft operatively connected to the drive shaft of an electric motor and in coaxial alignment with the drive shaft. A second shaft extends from the first shaft, with a gear box being disposed therebetween. The outer end of the second shaft has a polygonal cross sectional shape so as to receive a socket mounted on a drill or wrench. Upon actuation of the drill or wrench, the second shaft and connected first shaft are rotated, which in turn rotates the motor drive shaft. The motor drive shaft is connected to at least one rotatable screw upon which a gate is slidably tracked so as to move between open and closed position upon rotation of the screw via rotation of the drive shaft. Thus, if the motor fails, the drive shaft can still be rotated to turn the screw, and thereby raise or lower the gate, by operation of the drill or wrench which turns the first and second backup system shafts. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a race car transport trailer having a rear gate movable between raised and lowered positions, with the gate being shown in a raised position. 
     FIG. 2 is a rear view of the trailer taken along lines 2--2 of FIG. 1, with the gate being in a raised position, as shown by solid lines, and with the broken lines showing the gate in a lowered position. 
     FIG. 3 is a partial top plan view taken along lines 3--3 showing the gate screw backup system of the present invention. 
     FIG. 4 is a perspective view showing the distal end of the backup system shaft. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the drawings, a race car transport trailer is generally designated by the reference numeral 10. The trailer 10 includes a rear gate 12 which is movable between a raised position, as seen in FIG. 1 and as shown in solid lines in FIG. 2, and a lowered position, as shown in broken lines in FIG. 2. The gate 12 is adapted to lift a race car 14 for storage upon a raised shelf 15 within the trailer 10, and for lowering the car for removal from the shelf. 
     The gate 12 is mounted in a conventional manner at its opposite side edges to a pair of rotatable screws 16. The screws are housed within a C-shaped channel 18 at the rear end of the trailer 10 adjacent the opposite sides 20 thereof. 
     An electric motor 22 is provided for rotating the screws 16 through a series of linkages or interconnected shafts. More particularly, the motor 22 includes a drive shaft (not shown) which extends into an electric brake 24. The brake 24 has an output shaft (not shown) extending into a gear box 26. Preferably, the gear box 26 has a reduction ratio of 10:1. The gear box 26 has a pair of oppositely disposed output shafts which terminate in U-joints or yokes 28. In turn, yokes 28 are connected to yokes 30 on the inner ends of drive shafts 32. The outer ends of drive shafts 32 terminate in yokes 34 which are connected to yokes 36 mounted on the output shafts of a 90° gear box 38. The gear boxes 38 are operatively connected to the lower ends of the screws 16. 
     Upon actuation of the motor 22, the interconnected motor 22, gear box 30, drive shafts 32, and gear boxes 38 rotate the screws 16 such that the gate 12 is raised or lowered. The motor 22 is reversible such that rotation of the screws in one direction causes the gate 12 to slidably track along the screw flighting in an upper direction, and reversal of the motor causes the screws to rotate in the opposite direction such that the gate slidably tracks downwardly along the screw flighting. 
     The above description of the transport trailer gate and the screw assembly for raising and lowering the gate is conventional and does not constitute a part of the present invention. 
     The present invention is directed towards a backup system for the gate screw assembly. The backup system is best seen in FIG. 3, and includes a shaft 40 extending from the motor 22 in a direction opposite the motor drive shaft and co-axially aligned therewith. A flex coupler 42 interconnects the shaft 40 with a first shaft 43 extending from a gear box 44. Preferably, the gear box 44 has a 1:1 ratio. A second shaft 46 extending from the gear box 44 is connected to an elongated shaft 48 by a coupler 50. The shaft 48 is journaled within one or more pillow block bearings 52 secured to the frame or floor 54 of the trailer 10. The shaft 48 terminates in a distal end 55 adjacent one of the side walls 20 of the trailer 10, as seen in FIGS. 3 and 4. The end 55 of the shaft 48 has a polygonal shape adapted to receive a socket 56. The socket 56 can be mounted in a known manner to a conventional electric drill 58 or to a wrench (not shown). 
     In operation, when the drill 58 or wrench is actuated with the socket 56 matingly engaging the end 55 of the shaft 48, the shafts 48, 46 and 40 are rotated, so as to drive or rotate the drive shaft of the motor 22, which in turn rotates the shafts 32, thereby rotating the screws 16 so as to raise or lower the gate. Thus, with the backup system of the present invention, in the event that the motor 22 fails, the gate 12 can still be raised or lowered so that the race car 14 can be placed into or removed from the trailer 10. 
     It is understood that the screw backup system of the present invention can be utilized in other environments wherein a gate or door or other objects are raised and lowered, or opened and closed, by the rotation of the drive shaft of a motor. In such other applications, the backup system can override the failure of the motor so that the gate, door or object can be moved to a desired position. 
     Whereas the invention has been shown and described in connection with the preferred embodiments thereof, it will be understood that many modifications, substitutions, and additions may be made which are within the intended broad scope of the following claims. For example, the shaft 48 may extend to any access location on or under the trailer, and does not have to extend perpendicularly to the gear box shaft 40. 
     From the foregoing, it can be seen that the present invention accomplishes at least all of the stated objectives.