An instructional device for use in connection with ball games

摘要

727,281. Practising golf. BLAKE, M. V. Nov. 3, 1953 [Nov. 12, 1952], No. 28573/52. Class 132(2). A device for testing the correctness of the point in the swing at which a person hits a ball comprises a handle having an extension on which a weight movable towards and away from the handle is mounted, a movable stop to obstruct movement of the weight away from the handle, and a control means for the stop operative to move it so as to release the weight when the handle and extension attain a particular angular velocity. The device may be mounted in or on an actual club or bat, so that a golf swing may be practised in a confined space, a tubular extension 11 of a handle 10 is tapped at its free end to enter into a closing cup 12 forming a guide for a slidable rod-member 13 which is urged towards the handle by a spring 15. Two arms 17 are pivoted to the rod 13 and are urged apart by a spring 18 to project through slots 19 in the member 11 and form a stop preventing an annular weight 20 from sliding away from the handle. During the swing of the club, centrifugal force urges the rod away from the handle, overcoming the thrust of the spring 15, the arms 17 being retracted and releasing the weight 20 which moves to abut a stop 25 and emit a sound by which a watcher knows if the ball has been hit at the moment of greatest angular velocity of the club. The initial compression of the spring 15 may be varied by screwing the member 11. into the cup 12. In a modification the ring 20 is automatically returned to abut the stop 21 by a spring and the rod 13 has a guiding extension passing through an aperture in the end of the closing cup 12.