Abstract: A caliper has a pair of arms which are connected for rotation about a pivot point. Each arm has a tip and a contact surface is connected to one of the arms. The caliper includes a mechanical or electronic indicator which is responsive to the relative position of the arms for providing an indication of a dimension, such as the diameter, radius, circumference, or cross-sectional area, of an object. The caliper has an extended range and can provide an indication of the dimension when the tips of the arms and the contact surface simultaneously contact nondiametrically opposed points on the surface of the object.

Abstract: A pair of pivotally connected crossed arms define tongs having handles at one end and recessed jaw parts at the other. The recesses in the jaw parts are of a size to receive therein the pointed end tips of a crab shell whereby a crab may be easily lifted without danger of being clawed. One of the arms carries a scale and the other a pointer such that when the tips of a crab shell are engaged in the recesses the distances between the tips is instantly indicated and a determination made whether or not the crab is above a minimum size to be kept.

Abstract: A capacitive extensometer utilizes an extensometer frame having a pair of arms connected together about a hinge axis at first remote ends, and having second ends which include specimen contacting members for engaging the surfaces of a specimen to be tested. A capacitive type sensing arrangement is mounted on the arms, and is used with conventional circuitry for determining arm motion with respect to each other. The sensor is made so that it can be adjusted, and also can compensate for nonlinearities by utilizing differently shaped elements. The ability to mount and protect the capacitor sensor appropriately, while obtaining a relatively large output signal enhances the operability of the extensometer.