Abstract:
A screwdriver element includes two bits, each with a sinuous distal tip end and a screw element includes a head having an X-shaped slot that has sinuous side walls. The bit distal tips have a left-handed shape and a right-handed shape and the side walls of the screw element head are curved in a corresponding manner whereby twisting the screwdriver after the tip is engaged with the screw head slot will cause the screw driver tip to be drawn into tight engagement with the screw head.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to the general art of tools, and to the particular field of tools having work-engaging force-exerting portions inserted into a cavity. 
   2. Discussion of the Related Art 
   Screws are an integral part of most building elements. Assembling many items requires tightening a screw into place. This is generally accomplished using a screwdriver of some sort. 
   Most craftsmen and, indeed, most people, who have worked at the task of tightening a screw into place, have had the unpleasant experience of having the screw driver slip off of the screw. When this occurs, the screw head may be damaged, or the area adjacent to the screw may be damaged, and the worker may be hurt. None of these results are desirable. 
   The art contains several examples of screws that are designed to avoid the just-discussed slipping problem. The Phillips head screw is one example of such a screw. 
   However, even the Phillips head screw requires effort from the worker to keep the screw driver tip engaged in the slots of the screw. Such effort degrades the effort used to turn the screw. This may be important in cases, such as when the screw is rusted or otherwise attached to a substrate. 
   Therefore, there is a need for a system that will keep a screwdriver tip engaged with a screw head. 
   However, even more than simply keeping a screwdriver tip engaged with the screw head, it would be very helpful if there were some means for actually assisting a worker in keeping the screwdriver tip engaged with the screw head. The worker could then focus his or her entire concentration on rotating the screw as required. 
   Therefore, there is a need for a system that will assist a worker in engaging a screwdriver tip with a screw head. 
   Since screws must be forced into place and backed out of place, the above-described difficulties can occur during both operations. 
   Therefore, there is a need for a system that will assist a worker in engaging a screwdriver tip with a screw head during both the setting and removing of a screw. 
   PRINCIPAL OBJECTS OF THE INVENTION 
   It is a main object of the present invention to provide a system that will keep a screwdriver tip engaged with a screw head. 
   It is another object of the present invention to provide a system that will assist a worker in engaging a screwdriver tip with a screw head. 
   It is another object of the present invention to provide a system that will assist a worker in engaging a screwdriver tip with a screw head during both the setting and removing of a screw. 
   SUMMARY OF THE INVENTION 
   These, and other, objects are achieved by a screwdriver/screw unit that includes a screwdriver having two bits, each of which includes a sinuous tip distal end with one curve being associated with a right-hand screw rotation and the other curve being associated with a left-hand screw rotation. A screw head includes an X-shaped slot having curved sidewalls. The sidewalls are curved to accommodate the curved tip distal ends. When the tip distal ends are accommodated in the slot of the screw, rotation of the screwdriver will force the curved tip against the curved wall of the screw slot. The corresponding curves will cause the screwdriver tip to be engaged with the screw head slot wall. One tip is used to drive the screw forward, and one tip is used to back the screw out. 
   Using the screwdriver/screw unit embodying the present invention will permit a worker to focus all of his attention and energy into rotating the screwdriver and none of his attention will have to be used in keeping the screwdriver engaged with the screw. The unit embodying the present invention automatically engages the screwdriver tip with the screw head, and this engagement increases as torque on the screwdriver is increased. Thus, when a greater force is required to move a screw, this increased force will assist in keeping the screwdriver engaged with the screw head. With many prior art screwdrivers, the increased force may create a situation where the likelihood of the screwdriver slipping off of the screw is increased. The two bits and screw head X-shaped curve will permit the unit embodying the present invention to be used to move a screw forward or backward with the same advantages. 

   
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       FIG. 1  is a perspective view of a handle of a screwdriver/screw unit embodying the present invention. 
       FIG. 2  is a perspective view of a right-handed bit of the screwdriver/screw unit embodying the present invention. 
       FIG. 3  is a perspective view of a left-handed bit of the screwdriver/screw unit embodying the present invention. 
       FIG. 4  is a top plan view of screw head of the screwdriver/screw unit embodying the present invention. 
       FIG. 5  is a side view of screw head of the screwdriver/screw unit embodying the present invention. 
       FIG. 6  is a perspective view of a screwdriver tip and a screw head of the screwdriver/screw unit embodying the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description and the accompanying drawings. 
   Referring to the Figures, it can be understood that the present invention is embodied in a screwdriver/screw unit  10  that fulfills the above-stated objectives and overcomes the disadvantages of the prior art. 
   Screwdriver/screw unit  10  comprises a screwdriver  12  which includes a handle element  14  having first face  16  that is a working face when screwdriver  12  is in use, a side wall  18  which is contacted by a worker when screwdriver  12  is in use, a second end  20 , and a longitudinal axis  22  which extends between first face  16  and second end  20 . 
   A bit-accommodating bore  30  is defined in handle element  14  to extend from first face  16  toward second end  20  in the direction of longitudinal axis  22 . Bit-accommodating bore  30  is known and thus will not be further discussed in detail. 
   A first bit element  40  includes a first end  42 , which is a proximal end when first bit element  40  is in use, and a projection  44  on first end  42 . Projection  44  is sized and shaped to be releasably accommodated in bit-accommodating bore  30  in a known manner to releasably, but securely, attach the first bit element  40  to the handle element  14  for use. 
   A tip end  50  includes a distal end  52  when first bit element  40  is in use. Tip distal end  52  includes a sinuous curved portion  54  which curves in two directions  56  and  58 , with a plane containing distal end  52  being oriented perpendicular to a plane containing longitudinal axis  22  when first bit element  40  is attached to handle element  14 . 
   A second bit element  70  includes a first end  72 , which is a proximal end when second bit element  70  is in use, and a projection  74  on first end  72 . Projection  74  is sized and shaped to be releasably accommodated in bit-accommodating bore  30 . 
   Second bit element  70  further includes a tip end  76  which includes a distal end  78  when second bit element  70  is in use. Tip distal end  78  includes a sinuous curved portion  80  which curves in two directions  82  and  84 . A plane containing distal end  78  is oriented perpendicular to a plane containing longitudinal axis  22  when second bit element  70  is attached to handle element  14 . Curves  82  and  84  of sinuous curved portion  80  are opposite to curves  56  and  58  of sinuous curved portion  54  of first bit element  40 . 
   The opposite curvature of the sinuous curved portions  54  and  80  permit the screwdriver  12  to be used to advance a screw and to withdraw a screw as will be understood from the following description. 
   A screw element  90  includes a screw head  92  having a first end  94  that is a top end when screw element  90  is in place and an X-shaped slot  96  which is defined in first end  94 . 
   X-shaped slot  96  includes a first curved wall  100  which is shaped in the form of a “C” and has a first arcuate section  102 , a second arcuate section  104 , and an elongate section  106  connecting first arcuate section  102  to second arcuate section  104 . 
   X-shaped slot  96  further includes a second curved wall  110  adjacent to first curved wall  100  and which is shaped in the form of a “C” having a first arcuate section  112 , a second arcuate section  114 , and an elongate section  116  connecting first arcuate section  112  to second arcuate section  114 . 
   As can be understood from  FIG. 4 , the curves of first arcuate section  102  and second arcuate section  114  are opposite to each other and complementary to curves  56  and  58  of sinuous curved portion  52  of first bit element  40  whereby the sinuous curved portion  52  of first bit element  40  snugly engages first arcuate section  102  and second arcuate section  114  of the second curved wall portion  110  when screwdriver  12  is engaged with screw element  90  for driving the screw element  90  in a first direction. 
   As can also be understood from  FIG. 4 , the curves of second arcuate section  104  of first curved wall portion  100  and first arcuate section  112  of second curved wall  110  are opposite to each other and complementary to curves  82  and  84  of sinuous curved portion  80  of second bit element  76  whereby sinuous curved portion  80  of second bit element  76  snugly engages second arcuate section  104  of first curved wall portion  100  and first arcuate section  112  of second curved wall portion  110  when screwdriver  12  is engaged with screw element  90  for driving screw element  90  in a second direction with the second direction being opposite to the first direction. 
   A first dividing wall  120  separates first arcuate section  102  of first curved wall portion  100  from first arcuate section  112  of second curved wall portion  110 , and a second dividing wall  130  separates second arcuate section  104  of first curved wall portion  100  from second arcuate section  114  of second curved wall portion  110 . The dividing walls  120 ,  130  act to capture the distal end tip of the bit elements  40 ,  70  and hold those tips against the curved walls so the screw driver does not slip off the screw element. 
   The use positions of the screw driver and the screw element are shown in  FIG. 6 . 
   Operation of unit  10  can be understood from the teaching of the foregoing disclosure. Therefore, the operation will not be discussed in detail. To drive the screw element in a clockwise direction with respect to centerline  22 , the tip of bit element  40  is inserted into the X-shaped slot  96  on the screw element  90  with the curved portions of the bit element abutting the corresponding curved portions of the curved walls of the screw element  90 . The screw driver  12  is then rotated in a clockwise direction about longitudinal axis  22 . Retrograde movement of screw  90  is achieved by using bit element  70  and rotating the screw driver  12  in a counterclockwise direction with respect to longitudinal axis  22 . 
   It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangements of parts described and shown.