This invention relates generally to testing tools, and more particularly, to testing tool adapters for shear testing of adhesives used in securing wooden flooring to structural members and in securing gypsum-based wallboard to framing.
The American Society for Testing and Materials (ASTM) has developed testing standards for shear testing. Two of the testing standards are C 557-93a--Standard Specification for Adhesives for Fastening Gypsum Wallboard to Wood Framing (hereinafter ASTM C 557) and D 3498-93--Standard Specification for Adhesives for Field-Gluing Plywood to Lumber Framing for Floor Systems (hereinafter ASTM D 3498). In these two standards, ASTM specifies a protocol as to how a shear test should be performed. ASTM sets forth in these standards, the types of materials to be used, the starting conditions of the test, the duration of the test, the manner in which the test is conducted, and the minimum requirements for passing the test. Additionally, ASTM recommends a test method and device which may be used to perform the shear tests in D 905-94--Standard Test Method for Strength Properties of Adhesive Bonds in Shear by Compression Loading (hereinafter ASTM D 905). ASTM D 905 is herein incorporated by reference.
This known testing machine has significant disadvantages. Its structure limits its use to only a compression testing machine, and not a tension testing machine. The time involved to change test specimens is long. When initially positioning the specimen, it is necessarily preloaded with the weight of the blade. The prior art machine is without a mechanism to correct the shear test results for the weight of the blade. Indeed, specification D 905-94 indicates that many factors will bias the measurement obtained with the testing tool described therein, such as the design of the shear strength testing tool.
Another problem is that the prior art testing tool is made of steel. The machine was deliberately constructed out of steel because the design required the strength of the steel in order to have the machine sustain the forces applied to it. However, the use of steel causes significant problems. The weight of the steel that aided in the shear test causes operator fatigue problems because the operator must manually lift the heavy blade while positioning the test specimen. Additionally, the heavy blade frequently is dropped by the operator falling on the operator's hand or on the test specimen--potentially ruining the specimen because of the impact loading. This process of manually lifting the blade, and positioning the specimen is time-consuming. Additionally, the cost of manufacturing this testing device in steel is high. Different shear testing machines are required under ASTM C 557 and D 3498.
As such, a need currently exists for a shear testing device of universal utility in that it can be used in both compression and tension testing modes, and which is safer and easier to use, less expensive to construct and operate, and lest likely to exhibit a testing bias wherein the test specimens can be of varying size without changing the adapter, and can be operated in a tension or compression force-producing setting.
The present invention recognizes and addresses the foregoing disadvantages, and other prior art constructions.