Patent ID: 7603952
Filing Date: 2009-10-20
Classification: A62B,B61B

Abstract:
1. An apparatus comprising: a longitudinal rail assembly mounted on support members, said members arranged such that said rail assembly is generally horizontal; a trolley for carrying a load, said trolley being movable along the rail assembly; the trolley comprising a body, a center pair of wheels and two side pairs of wheels, said center pair being disposed in a radial space between said side pairs, each pair being rotatable about a respective axis, the wheels of each pair being disposed on opposite sides of said body; the rail assembly having two longitudinal channels therein, each channel arranged to receive a respective one wheel of each pair; the channels being laterally spaced such that the body of the trolley can be received therebetween for movement therealong; each channel being defined by at least a first bearing surface and a second bearing surface, said bearing surfaces being arranged opposite one another; each bearing surface comprising a central section and two side sections, each side section being disposed on an opposite side of said central section, the side sections of the first bearing surface extending toward the second bearing surface and vice versa; each wheel being of a shape such that said wheel engages the central and side sections of one of the bearing surfaces, thereby resisting loading of the trolley in multiple directions; wherein a distance between the central sections of the first and second bearing surfaces of each channel is greater than a diameter of the respective one wheel of each pair such that said wheel engages only one of said bearing surfaces, thereby allowing rotation of said wheel for movement of the trolley along the rail assembly; the axis of each side pair of wheels intersecting with a first longitudinal axis of the rail assembly and the axis of the center pair of wheels intersecting with a second longitudinal axis of said rail assembly, said longitudinal axes being spaced apart such that said side pairs engage the first bearing surface and said central pair engages the second bearing surface, the axes of the side pairs of wheels and the center pair of wheels being parallel.