Patent ID: 8442777
Filing Date: 2013-05-14
Classification: G01N

Abstract:
1. A system for measuring rolling resistance, comprising: an elongated rigid rod having opposed upper and lower ends, the upper and lower ends being free; an elongated horizontal support rigidly mounted on a central portion of the rigid rod, the horizontal support extending orthogonal to the rigid rod; a pair of retainers extending downward from opposing ends of the horizontal support, respectively, each of the retainers having a free end adapted for rigidly holding a sample of a first test material so that a hemispherical portion of the first material protrudes from the free end of each of the retainers, the rod, the horizontal support, and the retainers forming a substantially cruciform pendulum adapted for being supported by the hemispherical portion of the first test material bearing upon a flat planar sample of a second test material, the first test material rolling upon the second test material when the rigid rod is deflected and released to produce an oscillating pendulum motion; a planar reflector mounted on the central portion of the rigid rod; a light source for generating a coherent light beam focused on the reflector; a photodetector positioned to receive a reflection of the coherent light beam when the light beam is reflected off of the planar reflector in order to determine an angular deviation φ measuring deflection of the rigid rod with respect to vertical; and a timer in communication with the photodetector for measuring a time-dependency of angular deviation φ and for timing periods of oscillation of the cruciform pendulum.