Patent ID: 7878315
Filing Date: 2011-02-01
Classification: F16D

Abstract:
1. A spring clutch comprising: an input member having a cylindrical clutch surface on its inner periphery; an output member mounted in said input member so as to be rotatable relative to said input member; and a cylindrical clutch spring mounted between said input member and said output member and including a torque transmission end through which torque is transmitted to said output member; wherein said input member, said output member, and said clutch spring are arranged such that, when said input member rotates in one direction, said clutch spring radially expands by contact with said clutch surface, thereby transmitting torque from said input member to said output member, and when the speed of said output member exceeds the speed of said input member, said clutch spring is radially compressed, thereby cutting off the transmission of torque from said input member to said output member; wherein said clutch surface is formed with at least one large-diameter recess to allow radial expansion of several turns of said clutch spring; wherein said input member is configured and arranged so as to be rotated by a turning torque of a driving source, other than said output member, that is external to said spring clutch; and wherein said torque transmission end of said clutch spring is in engagement with said output member, and an end of said clutch spring opposite said torque transmission end constitutes a free end such that said clutch spring is not positively fixed for rotation with a member that is rotatable relative to said output member, whereby said output member and said clutch spring are rotatable indefinitely other than when said clutch spring is radially expanded by contact with said clutch surface.