Abstract: In a drum brake provided with an automatic adjustment device (40c, 40d) effecting the elongation of a spacer interposed between the shoes (12, 14) in the proximity of the brake motor (22), a device (46, 34) makes it possible to neutralize the adjustment device when heavy braking is applied. This device (46, 34) comprises a lever (46, 34) pivoted on one shoe (12, 14) and provided with a projection against which the brake motor bears. A spring (50, 42) normally holds the lever in a position of rest on the shoe supporting it, and the spacer bears against the lever. On heavy braking, the lever pivots, thus neutralizing the adjustment device. The lever can in particular be the hand brake lever (34).

Abstract: The automatic adjustment of a drum brake, when the wear of the friction linings carried by the shoes justifies it, is obtained by way of an adjusting lever (30) mounted pivotally on one (12a) of the shoes and carrying a toothed quadrant (30a), on which a pawl (34) is normally engaged. A spacer connecting the ends of the shoes between which the brake motor is located interacts with the adjusting lever by way of a connection with play. To prevent inopportune adjustment as a result of heating of the drum, a blocking member (52) carried by a metallic strip (50) fastened to the pivot pin (36) of the pawl (34)immobilizes the latter in terms of rotation when the temperature exceeds a certain threshold, thus increasing the functional play.

Abstract: The assembly spring consists of a V-shaped elastic metal wire (R1), one end of one branch (61) of which forms a hook (71) which ensures the retention of the pivot (52) of the lever (50), the branch (61) passing through a passage (81) provided in a spacer (44), in order to stress it elastically toward the lever (50) in interaction with the other branch of the V (91) which has a mechanism (101) of anchoring on the web (18) of the shoe (14) carrying the lever (50). The anchoring mechanism consists of a wire portion (101) bent at 90.degree. relative to the plane of the V and interacting with the web (18) of the shoe (14) and the lever (50) adjacent it, to constitute a mechanism forming a stop. The invention is used for the braking of vehicles.