Patent ID: 6837337

Claim:
A fall arrest safety device comprising, in combination: a safety trolley having means to permit attachment thereto of a safety belt or safety harness worn by a user of the device; and a rail adapted to be fixed in a generally upright orientation on a structure on which the user is climbing or working; the rail having a profile which includes a non-symmetrical profile portion and the trolley defining a passageway of complimentary profile that matingly receives said non-symmetrical profile portion when the trolley is in a normal orientation of use with an upper end of the trolley above the lower end of the trolley, said non-symmetrical profile portion being of a shape that prevents installation of the trolley on the rail when the trolley is in a reverse orientation with the lower end of the trolley above the upper end of the trolley; wherein the trolley incorporates a brake which frictionally engages the rail for arresting movement of the trolley downwardly with respect to the rail, and means biassing the brake into frictional engagement with the rail, the brake being disengageable from the rail only by a deliberate act of the user against the effect of the biassing means.