Patent ID: 6397984
Filing Date: 2002-06-04
Classification: F16D

Abstract:
A clearance compensator for the shoes of a drum brake for motor vehicles, of a type including:three coaxial elements, comprising a first rod element with a head portion for fixing against rotation to a first brake shoe and a threaded stem portion (11c), an intermediate element (13) threadedly engaged to the said first rod element, a second rod element (12) with a head portion for fixing non-rotatably to a second brake shoe and a stem portion slidably connected to the intermediate portion (13) so as to be freely rotatable with respect thereto; a tubular insert (16) rotatably mounted to the intermediate element (13) for sliding axially thereon and capable of reaching an axial stop position (13d) on said intermediate element; a ratchet wheel (17) secured for rotation with the intermediate element (13) between the second rod element (12) and the tubular insert (16); a leaf spring (14) acting between the second rod element (12) and the tubular insert (16) so as to urge the second rod element (12) away from the intermediate element (13), the said leaf spring carrying a stop element (18a) for engaging the ratchet wheel (17); heat-sensitive bi-metal strip means for preventing the ratchet wheel (17) from rotating when the temperature of the brake exceeds a predetermined value; characterised in that the said bi-metal strip means include a bi-metal strip (18) fixed so as to project from the leaf spring (14), orientated so as to be substantially tangential to the ratchet wheel (17) and having the said stop element (18a) at the free end thereof; the said strip having a normal operating position in which the stop element (18a) engages the ratchet wheel (17) and a heat-inflected position in which the stop element (18a) is disengaged from the said ratchet wheel (17) at temperatures exceeding a predetermined value.