Apparatus for testing co-efficient of friction of a road surface

In an apparatus for testing the co-efficient-of-friction of a surface such as the surface of a road, the apparatus including

• a frame including longitudinally-extending members and being suitably mounted on a plurality of standards adapted to engage such surface.
• a plurality of standards supporting said frame,
• a carriage slidably mounted on said members,
• constant-force coiled spring means operatively connecting together said frame and carriage for retracting said carriage along said members upon completion of the testing operation by said apparatus.
• a tire securely mounted to a wheel rotatably mounted on said carriage,
• means on said frame for maintaining a span between the tire and such surface,
• means for rotating the wheel by which the tire rotates,
• a gauging tape in alignment with one of said members, and
• indicator means mounted on one of said members slidable with said carriage in a forward direction of motion for said carriage,
• the improvement comprising
• said rotating means including a motor having a shaft on which a first sprocket wheel having teeth is securely mounted thereto and which accelerates the speed of said tire upon its actuation,
• electronic means for actuating said rotating means whereby said carriage slides in a direction of forward motion along said members,
• said electronic means including
• means for sensing the speed of said rotating means as the speed of said tire increases to reach the predetermined value in said electronic means, and
• means for releasing said maintaining means,
• whereby the tire drops to engage such surface and at which dropping said indicator means halts on said one of said members at a gauge reading to indicate the co-efficient of friction of the surface to which the tire drops.