Tester for coordinate measuring devices

摘要

A tester for use in testing coordinate measuring devices includes a hub having a generally tubular body portion, an outer ring, and a plurality of spokes connected to the hub and to the outer ring, each of the spokes having a generally tubular body portion and extending radially from the hub. A plurality of holders are connected to respective ones of the plurality of spokes, and elements respectively supported by the holders are provided which are adapted for use in testing the coordinates of a measuring device. The generally tubular body portion of the hub and the generally tubular body portion of each of the spokes is composed of a bonded fiber material in which layers of circumferential windings alternate with layers of helical windings, and wherein the helical windings are wound of a fiber which has a negative coefficient of thermal expansion. The holders and the elements respectively supported by the holders are composed of a relatively hard material which has a small positive coefficient of thermal expansion.