Patent ID: 6216547
Filing Date: 2001-04-17
Classification: G01L

Abstract:
A pulley assembly for measuring driving element tension in a system driven by a tensioned endless driving element, said pulley assembly comprising:a rotatable pulley member having a driving element engaging outer surface engageable with the tensioned driving element such that the driving element applies a load to said pulley member directly related to the driving element tension, the load having a force component in a load measuring direction; anda load sensor comprising:an annular gauge ring comprising an inner mounting portion constructed and arranged to enable said gauge ring to be mounted adjacent said endless driving element and an annular outer ring portion;said gauge ring being positioned with respect to said pulley member such that the load applied to said pulley member causes relative movement between said mounting and ring portions;said gauge ring having strainable beam members extending in said load measuring direction and flexing beam members extending in a transverse direction generally perpendicular to said load measuring direction, said strainable beam members and said flexing beam members interconnecting said inner mounting and outer ring portions;said flexing beam members being thicker in comparison to said strainable beam members so that said flexing beam members are less subject to elongation and compression due to strain in comparison to said strainable beam members such that said flexing beam members substantially limit relative movement between said mounting and ring portions to said load measuring direction when the tensioned driving element applies the aforesaid load with the force component in said load measuring direction to said pulley member by (1) resisting elongation and compression to substantially prevent relative movement between said mounting and ring portions in said transverse direction and (2) flexing to allow limited relative movement between said mounting and ring portions in said load measuring direction;said strainable beam members being constructed and arranged such that the substantially limited relative movement between said mounting and ring portions creates a strain in said load measuring direction in said strainable beam members having a magnitude directly related to a magnitude of the force component in said load measuring direction;a strain measuring and outputting device operatively associated with said strainable beam members, said strain measuring and outputting device being adapted to measure the magnitude of the strain created in said strainable beam members and to thereafter output the measured strain magnitude as an output signal which can be used to calculate magnitude of the aforesaid force component and hence the driving element tension.