Loadcell probe for overload protection

Abstract

The present disclosure provides an electro-mechanical fuse-type configuration built into the probe that contacts the specimen during materials testing. The design includes an internal pre-loaded compression spring and an electrical contact switch. The coil spring preloaded to the desired safety load results in the probe assembly directly passing the load from the probe tip to the load cell for loads under the point where the spring additionally compresses. Upon deflection of the spring in excess of safety preload, the spring internally compresses within the probe coupling rather than the probe tip continuing to displace into the specimen, thereby switching the state of the electrical contact switch and stopping operation of the materials testing device. In a further configuration, excessive travel of the load cell coupling is detected, and, in response, operation of the materials testing device is stopped.