Device for slowing down and stopping machines rolling on rails

A slowing down and stopping device for a machine rolling on rails which have a head and a narrower web below said head, said device comprising a longitudinal axis and a longitudinally extending body for placing on top of said head of the rail for the purpose of receiving on top of the body a wheel of said machine and forming an abutment for said wheel, and means for connecting the device to the rail, the connecting means comprising a plate, resiliently yieldable claws which are mounted on the plate and are movable relative to said plate transversely of said axis between a spread-apart first position of rest for receiving said head therebetween and a second position in which said claws can close around and engage under said head, the plate being adapted to be applied against the top of the rail, and moving means pivotally connected to the plate and pivotable relative to said plate about an axis extending transversely of said longitudinal axis between an inoperative position in which inoperative position said moving means allow said claws to assume said first position and operative positions in which operative positions said movable means are cooperative with said claws for moving said claws toward each other and maintaining said claws in said second position thereof, said moving means comprising an element which is pivotally mounted on said plate and is rigid with said body so that said body is also pivotable about said transverse axis.