Grinding plates

Abstract

A grinding plate, and sets thereof, includes a plate generally in the shape of a disc or cylinder. The plate has a keyhole slot which provides for a passageway from a portion of the perimeter of the plate to the keyhole and has a width throughout the length of the slot sufficient to allow at least some portion of a swing device shaft of a predetermined dimension to pass through the slot and fit into the keyhole. The keyhole perimeter has a predetermined size and shape so that when the plate is moved in a predetermined direction along the shaft it provides a snug friction fit around the shaft at a preselected position or range on the shaft. Systems and methods for swing training using the grinding plates of the invention are also provided.

What is claimed is: 
     
         1 . A grinding plate comprising a plate generally in the shape of a disc or cylinder, wherein the plate has a perimeter and a central locus, an interior, and an exterior surface; the plate has a keyhole whose central locus is largely coterminous with the central locus of the plate and has a keyhole perimeter having an exterior which forms an inner edge of the plate; the plate has a keyhole slot which provides for a passageway from a portion of the perimeter of the plate to the keyhole and has a width throughout the length of the slot sufficient to allow at least some portion of a swinging device shaft of a predetermined dimension to pass through the slot and fit into the keyhole; the keyhole perimeter having a predetermined size and shape so that when the plate is moved in a predetermined direction along the shaft it provides a snug friction fit around the shaft at a preselected position or range on the shaft. 
     
     
         2 . The grinding plate of  claim 1  wherein the keyhole comprises a resilient coating around its exterior which facilitates the ability of the plate to fit snugly against the shaft in a friction fit. 
     
     
         3 . The grinding plate of  claim 1  wherein the keyhole slot comprises a resilient coating along its length which facilitates the ability of the plate to slide onto the shaft. 
     
     
         4 . The grinding plate of  claim 1  wherein the grinding plate comprises a swing tracking mechanism. 
     
     
         5 . A system for swing training comprising one or more grinding plates, wherein each grinding plate comprises a plate generally in the shape of a disc or cylinder, wherein the plate has a perimeter and a central locus, an interior, and an exterior surface; the plate has a keyhole whose central locus is largely coterminous with the central locus of the plate and has a keyhole perimeter having an exterior which forms an inner edge of the plate; the plate has a keyhole slot which provides for a passageway from a portion of the perimeter of the plate to the keyhole and has a width throughout the length of the slot sufficient to allow at least some portion of a swinging device shaft of a predetermined dimension to pass through the slot and fit into the keyhole, the keyhole perimeter has a predetermined size and shape so that when the plate is moved in a predetermined direction along the shaft of the club it provides a snug friction fit around the shaft at a preselected position or range on the shaft, the one or more plates having keyholes, keyhole slots and weights allowing for alternative, sequential or combined usage in training a user of the club to provide a training effect to the user's swing. 
     
     
         6 . The system of  claim 5  wherein the keyhole of each plate comprises a resilient coating around the keyhole's exterior which facilitates the ability of the plate to fit snugly against a club shaft in a friction fit. 
     
     
         7 . The system of  claim 5  wherein the keyhole slot of each plate comprises a resilient coating along the keyhole slot's length which facilitates the ability of the plate to slide onto a club shaft. 
     
     
         8 . The system of  claim 5  wherein one or more of the grinding plates comprises a swing tracking mechanism. 
     
     
         9 . A method for swing training comprising obtaining or providing to a trainee one or more grinding plates, wherein each of the one or more grinding plates comprises a plate generally in the shape of a disc or cylinder, wherein the plate has a perimeter and a central locus, an interior, and an exterior surface; the plate has a keyhole whose central locus is largely coterminous with the central locus of the plate and has a keyhole perimeter having an exterior which forms an inner edge of the plate; the plate has a keyhole slot which provides for a passageway from a portion of the perimeter of the plate to the keyhole and has a width throughout the length of the slot sufficient to allow at least some portion of a swinging device shaft of a predetermined dimension to pass through the slot and fit into the keyhole; the keyhole perimeter has a predetermined size and shape so that when the plate is moved in a predetermined direction along the shaft it provides a snug friction fit around the shaft at a preselected position or range on the shaft, the one or more plates having keyholes, keyhole slots and weights allowing for alternative, sequential or combined usage of one or more plates in training a trainee's swing of the swinging device, thereby providing a training effect for the trainee's swing; applying one or more of the grinding plates to the shaft to snugly fit on the shaft; and swinging the swinging device one or more times to obtain the training effect. 
     
     
         10 . The method of  claim 9  wherein the keyhole of each plate comprises a resilient coating around the keyhole's exterior which facilitates the ability of the plate to fit snugly against the shaft in a friction fit. 
     
     
         11 . The method of  claim 9  wherein the keyhole slot of each plate comprises a resilient coating along the keyhole slot's length which facilitates the ability of the plate to slide onto the shaft. 
     
     
         12 . The method of  claim 9  wherein one or more of the grinding plates comprises a swing tracking mechanism. 
     
     
         13 . The method of  claim 9  wherein the swinging device is a golf club. 
     
     
         14 . The method of  claim 9  wherein the swinging device is a hockey stick. 
     
     
         15 . The method of  claim 9  wherein the swinging device is a tennis racquet. 
     
     
         16 . The method of  claim 9  wherein the swinging device is a baseball or softball bat. 
     
     
         17 . The method of  claim 9  wherein the swinging device is a racquetball racquet. 
     
     
         18 . The method of  claim 9  wherein the swinging device is a cricket bat. 
     
     
         19 . The method of  claim 9  wherein the method comprises obtaining or providing to a trainee a set of one or more grinding plates, each of which has a friction fit at a different preselected position or range on the shaft so that when two or more plates are used, they are able to be positioned on the shaft simultaneously. 
     
     
         20 . The method of  claim 9  wherein the method further comprises the step of exerting force upon the one or more plates once a training session has been ended to disrupt the friction fit and dislodge the one or more plates from the club.