Abstract: This disclosure relates to methods and tools for calibrating a camera-based three-dimensional optical metrology system such as that used for non-contact measurement of strain in a materials test system. A tool is provided which holds a calibration plate within a test space of a load frame of a materials testing device. The tool includes a spindle which rotates around a rotational axis to a series of detent rotational positions. The spindle engages the calibration plate by a bearing configuration which allows the tilt angle of the calibration plate to be varied. The rotation of the spindle and the variation of the tilt angle provides for two degrees of freedom of movement within the test space. The resulting sequence of calibration plate positions is systematic and repeatable.

Abstract: This disclosure relates to methods and tools for calibrating a camera-based three-dimensional optical metrology system such as that used for non-contact measurement of strain in a materials test system. A tool is provided which holds a calibration plate within a test space of a load frame of a materials testing device. The tool includes a spindle which rotates around a rotational axis to a series of detent rotational positions. The spindle engages the calibration plate by a bearing configuration which allows the tilt angle of the calibration plate to be varied. The rotation of the spindle and the variation of the tilt angle provides for two degrees of freedom of movement within the test space. The resulting sequence of calibration plate positions is systematic and repeatable.

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.

Abstract: An adjustable stage mount includes a housing having a base defining a hole and an adjustable stage including a ball joint extension that rotatably engages the hole and is rotatably securable about the x-, y-, and z-axes. An adjustable indenter mount includes a housing defining a hole and an adjustable indenter including a ball joint extension that rotatably engages the hole and is rotatably securable about the x-, y-, and z-axes. A collision protection switch includes a first plate having three pairs of electrically conductive spaced apart pins wired to a voltage source in an open circuit, and a second plate having three electrically conductive balls. A spring pulls the first and second plates together causing the three balls to complete the circuit. A sufficient force against the second plate causes a ball to disengage and open the circuit. A two-objective microscope includes two parallel objectives, upper and lower light sources, three half-mirrors, and a camera.

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.

Abstract: The present disclosure relates to a snap grip indenter mount, used on a hardness tester, particularly a microhardness tester, or similar apparatus. The snap grip indenter mount includes three major components—an indenter ball adapter, an upper housing assembly (or snap-grip male element) and a lower housing assembly (or snap-grip female element). The indenter ball adapter forms a ball-and-socket arrangement with the lower housing assembly. The lower housing assembly includes various set screws for fixing the orientation and symmetry of the indenter ball adapter with the lower housing assembly.

Abstract: An adjustable stage mount includes a housing having a base defining a hole and an adjustable stage including a ball joint extension that rotatably engages the hole and is rotatably securable about the x-, y-, and z-axes. An adjustable indenter mount includes a housing defining a hole and an adjustable indenter including a ball joint extension that rotatably engages the hole and is rotatably securable about the x-, y-, and z-axes. A collision protection switch includes a first plate having three pairs of electrically conductive spaced apart pins wired to a voltage source in an open circuit, and a second plate having three electrically conductive balls. A spring pulls the first and second plates together causing the three balls to complete the circuit. A sufficient force against the second plate causes a ball to disengage and open the circuit. A two-objective microscope includes two parallel objectives, upper and lower light sources, three half-mirrors, and a camera.

Abstract: A materials testing grip for tensile testing of small fibers includes a pair of inwardlyconverging surfaces into which a fiber may be easily pressed, and which in fiber tension is characterized by increased gripping force.

Abstract: An extensometer for measuring strain in a materials test speciment including a frame, a pair of arms each having one end for contacting a portion of the specimen and a remote end, and a noncontact sensor assembly mounted on the arms to measure change in distance between the contact ends, the arms being pivotally supported between the ends by the frame at the centers of gravity of the arms and attached components of the sensor, to permit the arms to be freely pivotal.