Patent US 4,852,875

A swing training apparatus for use with a hand held sports implement having a head and a handle with a longitudinal axis extending between the head and handle includes a housing that is mounted to the implement at a position adjacent the head. A sleeve carried by the housing defines a bore with a bore axis generally parallel to the implement longitudinal axis. A slug is carried by the sleeve in the bore and has a metallic portion defining a first electrical contact. A spring is used to bias the slug into a position spaced away from the implement head. A second electrical contact is positioned to engage the first contact when a preset centripetal force urges the slug to travel toward the implement head when the implement is swung with sufficient force. An indicator emits an audible signal and emits the signal as the implements reaches the preset centrifugal force threshhold. Sufficient centripetal force thus moves the slug and causes it to engage the first and second contacts closing a circuit to the indicator. The apparatus can be adjusted to measure different centripeal threshholds. The performer receives audible information at the moment of peak centripeal force. Ideally, that moment should occur at impact. The apparatus works as a training device to aid the performer improve his/her timing.