Abstract: A machine for testing the force applied to jaws of an aneurysm clip. A pair of jaw support plates receive the jaws of the aneurysm clip on end portions thereof. One of the jaw support plates moves between a closed position and an open position in which the end portions of the jaw support plates are spaced so that the clip is open. A motor opens said one of the jaw support plates. Electric current supplied to the motor is measured to provide a measure of the force on the jaws of the clip.

Abstract: Disclosed is an improved device for testing the compression, tension, or spring rate of a spring or other resilient material. The device is adapted to automatically display the load reading of a spring at a preselected height by merely compressing the spring past the check point. Alternatively, additional displays may be provided so that load readings at different height settings can be displayed with a single compression of the spring through all of the check points. In addition, the rate of a spring can be readily determined by setting two check points a unit distance apart and utilizing the load reading from the first check point to establish the reference level of the meter. The spring tester includes an electronic control circuit comprising a plurality of sample and hold circuits and a corresponding plurality of thumbwheel comparators.

Abstract: A system for measuring or testing the firmness of a resilient object such as a mattress. A pressure applying platen or the like is driven by a motor into the object, and the pressure applied is measured through the utilization of a pressure sensitive transducer or the like. This generates electrical power proportional to the pressure, and a recorder displays information to provide a reading of the power generated. The generating means is also connected to control means for the motor, and a threshold circuit or the like is adapted to shut off and reverse the motor when the power generated reaches a predetermined level.

Abstract: A loaded spring in a pressure relief valve or other spring-loaded device is excited with acoustic vibrations and the resonant frequencies of selected vibration modes are measured. Changes in spring constant due to aging and high temperature are detected by monitoring the longitudinal vibration mode resonant frequency, and changes in loading by monitoring the transverse and/or torsional vibration mode resonant frequency. The pressure set point is ascertained from manufacturing data of resonant frequency versus set point.