Patent ID: 6546782
Filing Date: 2003-04-15
Classification: G01N

Abstract:
An apparatus for testing a wear resistance of materials and at least one lubricating property of a fluid under conditions where a workpiece is subjected to a fretting wear, said testing apparatus comprising:a testing chamber containing a first workpiece chuck, a second workpiece chuck, and a workpiece loading device, said first workpiece chuck being in communication with said workpiece loading device such that said workpiece loading device imparts a contact force to a workpiece held within said first and second workpiece chucks, and wherein said first and second workpiece chucks are constrained to move only in a pair of axis that are perpendicular to each other; an actuator rod passing through said testing chamber and having two ends, said first end residing in an ambient environment surrounding said testing chamber and said second end residing within said testing chamber, and wherein said second workpiece chuck is in communication with said actuator rod such that movement of said actuator rod imparts like movement to said second workpiece chuck; a motion generator in communication with said first end of said actuator rod such that said motion generator imparts a linear cyclic motion to said actuator rod, said motion generator comprising an electric motor, a cranking assembly attached to an output shaft of said electric motor, said cranking assembly having at least one member that follows a path of eccentric rotation relative to a rotation of said output shaft, said a crank arm having two ends, a first end fastened to said cranking assembly member having a path of eccentric rotation and a second end fastened to said actuator rod first end, thereby translating the rotational motion of said electric motor output shaft into a linear reciprocal motion of said actuator rod; a seal between said actuator rod and said testing chamber such that a fluid placed under pressure within said testing chamber will not escape from the testing chamber along the testing chamber/actuator rod interface; and at least one sealable conduit communicating with the testing chamber, whereby fluids and objects may be passed into and out from said testing chamber; wherein said cranking assembly is comprised of two nested eccentric shells interposed between said output shaft and said crank arm first end attachment point, said inner eccentric shell having the ability to be locked to said outer eccentric shell at any point of rotation within the bore of said outer eccentric shell, thereby providing a means of adjusting the amount of eccentric rotation the outer eccentric shell exhibits relative to said output shaft which varies between twice the sum and twice the difference of the eccentric offset of the bores of said inner and said outer eccentric shells; and wherein said testing chamber is a hollow cylinder, said workpiece loading device further comprises a solid metal cylinder having an outer diameter and surface finish to permit it to slide freely within said testing chamber inner bore, and wherein contact pressure between said first and second workpieces held in said first and second workpiece chucks is generated by the weight of said workpiece loading device impinging upon a horizontal array of said workpiece chucks containing workpieces, said horizontal array of workpiece chucks being arranged such that a surface of said first workpiece resides in contact with a surface of said second workpiece.