Torque compensated weight sensing modules

Abstract

A force sensing module with reduced sensitivity to torque in order to accurately measure weight in the presence of longitudinal and lateral torques, comprising two or more sensing means mounted vertically with output signal means combined and adjustable to minimize longitudinal torque response. The force sensing module further comprises a vertical support for lifting and supporting a load, a support arm coupled to the vertical support for engaging and holding a load, first and second sets of strain gauges, spaced from each other and either in vertical or horizontal alignment with each other. The strain gauges are connected at one end to the vertical support and at the other end to the arm for receiving a force proportional to the load and for receiving a torque from the arm. The force sensing module also comprises first and second Wheatstone bridges, wherein each Wheatstone bridge comprises one of the sets of strain gauges and at least one variable resistance coupled between the Wheatstone bridges with a resistors adjustable to reduce the sensitivity of the Wheatstone bridges to torque applied to the sets of strain gauges through the support arm. The force sensing modules are useful in the measurement of medical patient weights where great accuracy is required for diagnostic and treatment needs.