Importance

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Abstract

A buttonhole sewing machine drive motor is turned on with an on switch. A large foot pedal engages the drive pulley on the motor and drives a V-belt. The V-belt drives a pulley and a timing pulley, which in turn drives a timing belt. The timing belt drives a clutch timing pulley, which freely rotates around a main drive shaft of the buttonhole sewing machine. When a small foot pedal is pressed downward, an air-activated over-the-center toggle connection moves a slide bar which moves a clutch switch spring. Parallel extension on the clutch switch spring move thrust washers and an interposed thrust bearing. The thrust washers compress a clutch disc assembly which engages the clutch timing pulley. A switch bushing is locked to the clutch disc assembly, and brake springs in a hand wheel assembly are locked to the switch bushing. The brake springs engage a hand wheel disc which is connected to a hand wheel and which is connected to an end of the main drive shaft for turning the drive shaft. When the engagement force on the clutch switch spring is removed, the clutch assembly ceases to rotate with the clutch timing pulley, which continues to freely rotate while the drive shaft is stopped. The hand wheel assembly may be used to turn the drive shaft.

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First Claim