US 7,600,411 B2
	Surface friction testing apparatus
Malcolm Bailey, Radlett (United Kingdom)
Assigned to Slipalert LLP, Hertfordshire (United Kingdom)
Appl. No. 10/561,104 PCT Filed Jun. 07, 2004, PCT No. PCT/GB2004/002389 § 371(c)(1), (2), (4) Date Aug. 17, 2006, PCT Pub. No. WO2004/113879, PCT Pub. Date Dec. 29, 2004.
Claims priority of application No. 0313970.6 (GB), filed on Jun. 17, 2003.
Prior Publication US 2006/0277973 A1, Dec. 14, 2006
Int. Cl. G01N 19/02 (2006.01)

U.S. Cl. 73—9

16 Claims

1. A portable surface friction testing apparatus for determining a coefficient of friction of a test surface during a test run, the apparatus comprising a trolley having a mass and comprising a first plurality of wheels for contacting the test surface throughout the test run, at least one additional wheel, and an underside fitted with at least one slider to induce friction between the body and the test surface as the body moves across the test surface wherein the first plurality of wheels and the at least one slider provide directional stability to the trolley, and are positioned such that a force between the at least one slider and the test surface can be determined and remains constant under any particular value of uniform deceleration; and a ramp of known incline and length adapted to propel the body to an initial velocity of the test run wherein the ramp and the trolley are arranged such that the at least one additional wheel bears a portion of the mass of the trolley on the ramp during a period in which the trolley accelerates down the ramp, but wherein the portion of the mass of the trolley borne by the at least one additional wheel is transferred to the at least one slider at commencement of the test run.