Abstract: An apparatus for selectively adding weight to the hollow shaft of a hand-held implement. One embodiment includes an upper cylindrical member, a lower member, and an expansion ring that fits between the upper and lower members. These components are sized slightly smaller than the inside diameter of a hollow shaft, such as a golf club shaft. Each component includes an axial bore, through which a screw with an elongated barrel extends. The axial bore of the upper member is enlarged at its upper terminus to receive the cap of the screw, and the axial bore of the lower member is threaded to receive the screw. This assembly is inserted into a hollow shaft, and as the screw is tightened, the lower member is drawn into the upper member, compressing the expander ring axially causing it to expand radially until a friction fit with the inside surface of the hollow shaft is achieved.

Abstract: An apparatus for selectively adding weight to the hollow shaft of a hand-held implement. One embodiment includes a deformable upper cylindrical member, a lower member, and a rod coupled between the upper and lower members. These components are sized to fit within a hollow shaft, such as a golf club shaft. The upper deformable cylinder includes a chamber at its upper end, into which an oversized insert is inserted. This causes the deformable cylinder to expand radially creating a friction fit with the inside surface of the hollow shaft. The lower member may include an annular deformable member, such as an o-ring or a sleeve, stretched over its outside surface to create a snug fit within the shaft.

Abstract: An apparatus for selectively adding weight to the hollow shaft of a hand-held implement. One embodiment includes an upper cylindrical member, a lower member, and an expansion ring that fits between the upper and lower members. These components are sized slightly smaller than the inside diameter of a hollow shaft, such as a golf club shaft. Each component includes an axial bore, through which a screw with an elongated barrel extends. The axial bore of the upper member is enlarged at its upper terminus to receive the cap of the screw, and the axial bore of the lower member is threaded to receive the screw. This assembly is inserted into a hollow shaft, and as the screw is tightened, the lower member is drawn into the upper member, compressing the expander ring axially causing it to expand radially until a friction fit with the inside surface of the hollow shaft is achieved.

Abstract: An apparatus for improving the dynamic response of a golf club by selectively weighting the grip end of the club. One embodiment comprises a cylindrical member having a lower base portion and an upper housing portion. The base is sized to be inserted into the grip end of a golf club shaft with the upper housing extending wholly or partially from the end of the shaft. The housing has a hollow, open chamber in which a weighted insert is inserted and removably secured. Another embodiment comprises upper and lower complimentary cylindrical wedges, each with a bore along its longitudinal axis, sized to be inserted into the grip end of a golf club shaft and secured by a screw extending through the longitudinal bores and threaded into a threaded insert located in a cavity in the lower wedge.

Abstract: A device for coupling two shaft members of differing diameters. The device includes a barrel and a reaction mass. The barrel is hollow and includes an outside coupler formed by the exterior surface of an upper portion of the barrel, an inside coupler formed by the inside surface of the barrel, and a reaction mass interface formed by the exterior surface of a lower portion of the barrel. The outside coupler is sized to fit inside a hollow end of the first shaft member. The inside coupler is sized to receive the second shaft member. The reaction mass slides over the second shaft member and into position on the reaction mass interface of the barrel. The parts are secured together with an adhesive.

Abstract: An apparatus for improving the dynamic response of a golf club by selectively weighting the grip end of the club. One embodiment comprises a cylindrical member having a lower base portion and an upper housing portion. The base is sized to be inserted into the grip end of a golf club shaft with the upper housing extending wholly or partially from the end of the shaft. The housing has a hollow, open chamber in which a weighted insert is inserted and removably secured. Another embodiment comprises upper and lower complimentary cylindrical wedges, each with a bore along its longitudinal axis, sized to be inserted into the grip end of a golf club shaft and secured by a screw extending through the longitudinal bores and threaded into a threaded insert located in a cavity in the lower wedge.

Abstract: A weight collar for optimizing the dynamic response or feel of a sporting implement, such as a golf club. The collar comprises a notch or cut-out to allow the collar to be slipped over the shaft of the implement below the grip and a tapered interior wall to allow a snug fit between the inner wall of the collar and the exterior wall of the grip of the implement. Collars of varying weights may be substituted on an implement until the user subjectively determines that the implement has the best feel or until performance is maximized.

Abstract: An apparatus and method for improving the dynamic response of a golf club is disclosed. One embodiment is a shaft extension comprising a cylindrical member having a lower sleeve portion and an upper housing portion. The sleeve is sized to be inserted into the grip end of a golf club shaft with the upper housing extending from the end of the shaft. The housing has a hollow, open chamber in which a weighted insert is inserted and removably secured. Interchangeable inserts with varying masses are provided such that the dynamic response of the club may be tuned by adjusting the location of grip-end node of the fundamental modeshape of the club's response to a predetermined input.