Abstract:
A swing trailer having a first plate rotatably attached to a second plate and a foot placement device on top of the first plate, and a first stop on the first plate and a second and a third stop on the second plate. The engagement of the first stop with the second and third stops limit rotation of the first and second plates to approximately 90°.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates, in general, to a swing trainer, and, in particular, to a swing trainer that has a predetermined rotation. 
     DESCRIPTION OF THE PRIOR ART 
     In the prior art various types of swing trainers have been proposed. For example, U.S. Pat. No. 5,810,673 to Castleberry discloses a swing training device having an upper and lower plate that rotate with respect to each other. However, this device is huge, long, not light weight abd has no stop. 
     U.S. Pat. No. 5,318,290 to Sawyer discloses a swing training device having an upper and lower plate that rotate with respect to each other. However, this device is not portable, cannot be used on any surface, and you need tools, i.e. a hammer to pound spikes into the ground to set it up. In addition, there is no stopper and no ball bearings. 
     U.S. Pat. No. 4,560,165 to Witten et al. discloses a swing training device having an upper and lower plate that rotate with respect to each other and a spring torsion device. However, this device is huge, not light weight, has no stopper and is too tall. 
     U.S. Pat. No. 3,372,930 to Sertich discloses a swing training device having an upper and lower plate that rotate with respect to each other and a strop to hold the user&#39;s foot. However, this device has no stopper, does not have an easy glide bearing system, will not work on any surface, and need tools, i.e. a hammer to place on the insulation. 
     In contrast to these prior art references and the known prior art, the present invention provides a swing trainer having an upper and lower plate that rotate with respect to each other wherein the plates have a system limiting the rotation to a predetermined angle. 
     SUMMARY OF THE INVENTION 
     The present invention provides a swing trainer having an upper and lower plate wherein the upper and lower plates are pivotally attached to each other. Attached to the upper and lower plate is a system that limits the rotation of the upper plate to a predetermined angle. 
     It is an object of the present invention to provide a new and improved swing trainer system that is easy to use and needs no tools or special equipment to set up. 
     It is an object of the present invention to provide a new and improved swing trainer system that is light weight. 
     It is an object of the present invention to provide a new and improved swing trainer system that is small and portable and can be used on any type of surface. 
     It is an object of the present invention to provide a new and improved swing trainer system that can be used indoors or out doors. 
     These and other objects and advantages of the present invention will be fully apparent from the following description, when taken in connection with the annexed drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the present invention. 
     FIG. 2 a  is a top view of the first plate of the present invention. 
     FIG. 2 b  is a bottom view of the first plate of the present invention. 
     FIG. 3 a  is a top view of the second plate of the present invention. 
     FIG. 3 b  is a bottom view of the second plate of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Back foot lockout is one of the most common problems facing many baseball players and golfers, which is not addressed by hitting instructors and coaches. Back foot lockout occurs when the athlete fails to properly rotate their back foot during the course of their swing. This improper rotation of the back foot creates an improper or, in some circumstances, no rotation of the athlete&#39;s hip. 
     On the other hand, the present invention is designed to create muscle memory so that the muscle will react in a particular way to create a smooth, effective rotation of the back foot. The present invention trains the athlete through repetition and without conscious thought so that the athlete will have the proper hip movement creating a proper swing. 
     Referring to the drawings in greater detail, FIG. 1 shows the present invention  10  having fastening device  11 , holes  12  and  13 , first plate  20 , foot placement device  21 , second plate  30 , and attachment device  35 . While FIG. 1 shows that first plate  20  and second plate  30  are about the same length, one of ordinary skill would readily realize that the lengths of first plate  20  and second plate  30  may be different. For example, second plate  30  may be larger than first plate  20  allowing a user to place the present invention on an object to ensure that the present invention  10  will not shift when a user&#39;s foot is placed on the present invention  10 . 
     First plate  20  is manufactured from materials well known within the art to be lightweight and rigid such as, but not limited to, steel or plastics. First plate  20  has a top and bottom wherein the top and both form a predetermined thickness. A hole  12  is placed approximately in the center of plate  20  and hole  12  is, preferably, not threaded. During manufacture, the thickness of plate  20  is relatively uniform, however, plate  20  may be manufactured using different thickness. As the thickness of plate  20  increases, plate  20  will flex less when pressure is exerted upon it. 
     Attached to plate  20  is foot placement device  21 , which is shown in greater detail in FIG. 2 a . Foot placement device  21  is substantially rounded (as shown in FIG. 2 a ). The foot placement device  21  is elevated from plate  20  by a predetermined height of, preferably, 1½ inches. The foot placement device  21  enables the user to center the ball of their foot when using the present invention  10 . The top of plate  20  may also feature artificial turf. 
     Similar to plate  20 , plate  30  has a top and bottom and is of a predetermined thickness. Preferably, since plate  30  rests upon a driving range mat or the ground, plate  30  need not be as thick as plate  30 , which allows the present invention  10  to be lightweight. Second plate  30  is manufactured from materials well known within the art to be lightweight and rigid such as, but not limited to, steel, plastics, or the like. In an alternative embodiment, plate  20  may be manufactured from a first material and plate  30  may be manufactured from a second material, whereby the first and second plate materials are different. Hole  13  is approximately in the center of second plate  30 . While holes  12 ,  13  are described as being approximately in the center of both first plate  20  and second plate  30 , other placements of hole  12 ,  13  would not depart from the scope of the present invention  10 . 
     Both plate  20  and plate  30  are attached to each other by attachment device  11  passing through respective holes  12 ,  13  in plate  20  and plate  30 . Attachment device  11  may be any device known within the art that is used to attach objects together as long as first plate  20  may rotate with respect to second plate  30 . For example, first plate  20  may have a non-threaded hole  12  and second plate  30  may have a threaded hole  13 . A screw  11  will be threaded to plate  30 , but not to plate  20  to allow plate  20  to rotate with respect to plate  30 . If a screw is used as the attachment device  11 , the user may assemble and disassemble the present invention  10  to transport the present invention  10  and deploy it in various areas. In other embodiments, the attachment device may be a rivet whereby both plate  20  and plate  30  are permanently attached to each other and first plate  20  is allowed to rotate with respect to second plate  30 . In yet another embodiment, a snap connection is the attachment device  11  whereby both first plate  20  and second plate  30  are attached to each other. 
     FIG. 2 a  is a top view of plate  20 . While plate  20  is shown as being substantially rectangular in shape with rounded-off corners, one of ordinary skill would realize that plate  20  may be any shape well known within the art. 
     As described above, the foot placement device  21  is a substantially circular device. Preferably, during the construction of the present invention  10 , foot placement device  21  is attached to plate  20  by means well known within the art. In alternative embodiments, both first plate  20  and foot placement device  21  may be of unitary construction. Foot placement device  21  also prevents a force on plate  20  from interfering with the operation of the present invention  10 . 
     FIG. 2 b  is a bottom view of plate  20  having hole  12 , first projection or stop  22  and indent canal  23 . Stop  22  is part of the system that is used to limit the rotation of plate  20  to a predetermined arc. Plate  20  and stop  22  are attached to plate  20  by any conventional means or could be of unitary, one-piece construction. Stop  22  projects outward by a predetermined length and a predetermined width. 
     The bottom of plate  20  also features indented canal or groove  23  which allows plate  20  to rotate about a vertical axis through hole  12 . Additionally, canal  23  allows a friction reducing system to be used, which will be described below. Foot placement device  21  is placed over canal  23 , therefore, as a force is exerted on the foot placement device  21 , the force is directly applied to a friction reduction system located beneath plate  20 . This placement of the foot placement device  21  over the indented canal  23  also prevents other portions of plate  20  from touching plate  30  thereby providing a near friction-free environment. 
     FIG. 3 a  is a top view of plate  30  of the present invention  10  having hole  13 , second stop  31 , third stop  32 , and friction reducing system  33 . While plate  30  is shown as being substantially rectangular in shape with rounded-off corners, plate  30  may be any shape well known within the art. Additionally, while plate  20  and plate  30  are described as being substantially identical in shape and size, plate  20  and plate  30  may differ in both size and shape. 
     Friction reducing system  33  is attached to the top of plate  30  by any conventional means. The friction reducing system  33  may be any means known within the art for the purpose of reducing friction between two objects such as, but not limited to, ball bearings  36 , or the like. The size and shape of friction reducing system  33  is nearly identical to the size and shape of indented canal  23  found on first plate  20 . This allows the friction reducing system  33  to occupy the space of the indented canal  23  thereby providing a frictionless rotational movement while substantially preventing movement in the horizontal or vertical direction. As stated above, since the foot placement device  21 , that is part of plate  20 , substantially overlies the indented canal  23 , which is on the bottom of plate  20 , a force exerted upon the foot placement device  21  is exerted through plate  20  and to the friction reducing system  33  attached to the top of plate  30 . 
     Attached to the top of plate  30  is second stop  31  and third stop  32 . As shown in FIG. 3 a , third stop  32  is slightly left of an imaginary line AA through the center of plate  30 , and stop  31  is positioned approximately 90° clockwise from stop  32 . Stop  31  and stop  32  form an imaginary arc  34  of a predetermined angle, preferably about 90°. 
     FIG. 3 b  is a bottom view of plate  30  having hole  13  and a attachment device  35 . The attachment device  35  is affixed to the bottom of plate  30  by any conventional means and is any conventional gripping surface which prevents the present invention  10  from moving or shifting when in use. 
     Second stop  31  and third stop  32  limit the arc that plate  20  may traverse. This limitation is because the first stop  22  will hit either the second stop  31  or the third stop  32  when plate  20  rotates either clockwise or counterclockwise. As stated above, it is preferable that plate  20  rotates 90°, but one of ordinary skill would realize that other arcs may be beneficial. While the present invention  10 , is described as using first stop  22 , second stop  31 , and third stop  32 , it should be understood that any rotational limiting system may be used to limit the rotation of plate  20  with respect to plate  30  to a predetermined arc. 
     In order to use the present invention  10 , the user will set the present invention on a object such as, but not limited to, the ground, baseball diamond, grass, driving range, or the like. The attachment device  35  is a gripping surface of any conventional design and will prevent the present invention  10  from moving in a horizontal or vertical direction. Next, the user will place one foot on the object and the second foot, preferably their back foot, on the present invention  10 . The ball of the second foot should be placed on the foot placement device  21 . Preferably, the first foot and second foot of the user should be placed about shoulder width apart. Once the first foot is placed on the object and the second foot is placed upon the present invention  10 , the user will rotate the second foot until stop  21  of plate  20  impacts with stop  31  of plate  30 . As described above, the arc of this rotation is about 90°, but is dependent upon the imaginary arc  34  of the second stop  31  and third stop  32 . When the stop  21  engages stop  31 , both feet of the user are substantially parallel with respect to each other. In order to practice this movement, the user then must rotate their second foot by a predetermined angle, preferably 90°, so that the heel of the second foot is thrust backward, away from the body. This rotation of the back foot will cause the user&#39;s hip to rotate properly. 
     Although the back foot pivot and the method of using the same according to the present invention has been described in the foregoing specification with considerable details, it is to be understood that modifications may be made to the invention which do not exceed the scope of the appended claims and modified forms of the present invention done by others skilled in the art to which the invention pertains will be considered infringements of this invention when those modified forms fall within the claimed scope of this invention.