Patent ID: 6439762
Filing Date: 2002-08-27
Classification: G04B

Abstract:
A mainspring device that drives a primary wheel train by mechanical energy of a mainspring, comprising:a winding-up portion that accumulates energy in said mainspring; an addition-and-subtraction wheel train driven by addition and subtraction of accumulated energy corresponding to an amount by which the mainspring is wound up and unwound, respectively; an addition-and-subtraction wheel, disposed in said addition-and-subtraction wheel train, that rotates in correspondence with an amount by which said mainspring is wound up and unwound, said addition-and-subtraction wheel having a single plane of rotation; a lock mechanism actuated in response to the rotation of said addition-and-subtraction wheel to limit winding up and unwinding of said mainspring to a selected range of windings, and to thereby prevent transmission of torque having a value outside a set range from said mainspring to said primary wheel train; a winding-up wheel train that transmits torque to said addition-and-subtraction wheel train during winding-up operations of said mainspring, and wherein said lock mechanism comprises a winding-up lock mechanism portion that locks one of said winding-up wheel train and said winding-up portion in response to the rotation of said addition-and-subtraction wheel indicating that said mainspring is wound up to a number of windings equal to or greater than a first predetermined number of windings; and an oscillating weight and a drive gear driven by rotation of said oscillating weight to wind up said mainspring, said drive gear being coupled to said winding-up wheel train, and wherein said winding-up lock mechanism portion locks a gear in said winding-up wheel train, and wherein said winding-up lock mechanism portion comprises a slip mechanism section for preventing transmission of torque, during actuation of said winding-up lock mechanism portion, from said oscillating weight to said mainspring and said addition-and-subtraction wheel.