Patent ID: 7600628

Claim:
A carriage for driving handrails of walkways and moving stairs, comprising a body in the form of a vertical plate in which horizontal axis leading rollers are assembled for being supported on a guide next to the handrail, running therein; locking means for locking with a drive chain for the handrail; a free turning wheel intended to be supported against a cam profile of the guide to move the locking means from an operative position, in which it fixes the carriage to the chain, and an inoperative position, in which they release the carriage from said chain; and an arm horizontally projecting from the plate to engage with the variable pitch screws, wherein the mentioned locking means are formed by two pawls and by two actuating levers of said pawls; the pawls of which are linked to the body of the carriage according to first horizontal pins, around which they can swing between an operative vertical position, in which they project from the body at the upper part to be introduced between two consecutive pulley wheels of the drive chain, and an inoperative horizontal position, in which they are aligned and establish a support track for said pulley wheels at the upper part; and the actuating levers of which are linked to one another at an intermediate point by means of a second horizontal pin which is assembled in the body of the carriage by means of a vertical slide, located below the linkage points of the pawls to the carriage, through which it can move vertically, whereas at the upper end each lever is linked to a pawl by means of third symmetrical and parallel pins located inside and below the first linkage pins for linking said pawls with the body of the carriage in the inoperative position of the pawls, and inside and above the mentioned linkage points of the pawls in the operative position; at least one of the levers bearing at its lower end the free turning wheel which will be supported against the mentioned cam profile to vertically move the second linkage pin of said levers in the mentioned vertical slide between upper and lower limit positions, corresponding to the operative and inoperative positions of the pawls, the levers further having a compression spring assembled between their lower ends, which spring is kept tensed whatever the position of said levers may be.