Patent ID: 7192370
Filing Date: 2007-03-20
Classification: A63B

Abstract:
1. A string tensioning force controlling apparatus for a racket stringer, comprising: (a) a fixed base housing; (b) a string pulling mechanism having a support housing, a drive arrangement supported on said support housing, and a string pulling head adapted to engage a string and mounted on said support housing, said drive arrangement including a motor mounted to said support housing and having a rotary output shaft drivingly connected to said string pulling head for rotating said string pulling head in response to operation of said motor, said string pulling head also drivingly coupled to said drive arrangement and in response to operation of said drive arrangement adapted to apply a desired tensioning force on the string to produce a tensioned string, said support housing movably mounted on said fixed base housing for undergoing displacement relative to said fixed base housing in response to a force of the tensioned string being applied on said support housing via said string pulling head; (c) biasing means disposed between said support housing and said fixed base housing and adapted to bias said support housing to undergo displacement toward a first position relative to said base housing and to yield to allow said support housing to undergo displacement toward a second position relative to said fixed base housing upon applying said string tension force; (d) detection means disposed adjacent to said string pulling mechanism for detecting the displacement of said string pulling mechanism relative to said fixed base housing and generating an output signal representative of the displacement; (e) a central processing unit connected to said drive arrangement and to said detection means for receiving the output signal from said detection means and, in response thereto, operating said drive arrangement such that the desired tensioning force is accurately applied on the string so as to produce the tensioned string; and (f) a digital encoder disposed adjacent to said string pulling mechanism to detect the rotational displacement of said string pulling head relative to said support housing and to generate a second digital output signal representative of the rotational displacement to said central processing unit for controlling the operation of said motor.