Patent ID: 7886572

Claim:
A method for calibrating the timing of a backlash impulse device in a sport implement having a striking surface and a movable mass mounted therein, comprising the steps of; measuring the natural frequency of said striking surface of said implement; determining from said natural frequency a time of occurrence and a duration of a period of elastic recovery of said striking surface in a first vibration cycle following an impact on said striking surface and relating a movement of said movable mass to said first vibration cycle; adjusting a distance of travel of said movable mass during a strike of a ball with said sport implement such that an impulse generated by said movable mass during said strike occurs during said period of elastic recovery of said striking surface in said first vibration cycle; wherein said movable mass comprises mercury enclosed in a cylindrical capsule and said step of adjusting a distance of travel is effected by selecting a single cylindrical capsule from a plurality of cylindrical capsules each having a same volume of mercury therein and a unique movable-mass travel distance, and mounting said single cylindrical capsule inside said implement; and wherein said step of selecting is effected by extrapolation from two different vibration measurements of impulses on said striking surface, caused by two different ones of said cylindrical capsules alternately mounted in said implement, in two different experiments carried out at a same swing speed of said sport implement.