BACKGROUND OF THE INVENTION

Shear test machines are used to evaluate the shear strength or maximum shear stress of one or more materials. Typically, a shear test involves applying force to two different surfaces of a material and in opposite directions so that the material is stressed in a sliding motion. Commonly, materials such as metal, plastic, ceramic, composite substrates, adhesives, layered composites, and glued assemblies are tested.

In some applications, such as confirming proper adhesion of tile panels to underlying structural components (e.g., aluminum-to-aluminum or aluminum-to-composite via epoxy), a portable shear testing device is desirable. However, current portable shear testing devices can be difficult to use for such purposes because they rely on pneumatic pressure sensors that require cross reference sheets to interpret readings. Additionally, current portable shear testing devices typically have multiple moving parts and relatively high internal friction which can reduce the accuracy of measurements.

Therefore, an improved design that overcomes the disadvantages of the current portable shear testers would be valuable.

SUMMARY OF THE INVENTION

The present invention is directed to a portable shear testing device. In one embodiment, the device includes a shear force unit that has two elongated jaw members that are positioned adjacent to each other. One of the jaw members can be moved away from the other, stationary jaw member.

In one embodiment, one of the jaw members is moved by a pivotally mounted lever that laterally moves a load transfer block connected to the jaw member. In one embodiment, a digital load cell is positioned between the lever and the load transfer block. In one embodiment, a threaded knob is rotated to press against the lever.

Another embodiment of the present invention includes a drill guide that fits within a support baseplate. The baseplate can have a key portion that engages a key portion on the drill guide. The drill guide may include a drill shaft with a drill bit that is configured to cut a circular groove.

