Reivindicaciones

1. Brake pad or shoe wear detector of preferred application to railway vehicles, characterised in that it is made up of an elongated body for insertion in the actual body of the friction material, which, when it rubs against the brake disc as a result of friction material wear, closes the corresponding electrical circuit giving notice of the need to change the brake shoes or pads. 2. Brake pad or shoe wear detector of preferred application to railway vehicles, according to claim 1, characterised in that the detector is T-shaped and has two counterposed fins (3) which each engage in slots (9) made in the friction material of the brake shoe or pad, while the other fin (4) is facing the brake disc and will be the electrical element that comes into contact with the brake disc. 3. Brake pad or shoe wear detector of preferred application to railway vehicles, according to claim 1, characterised in that at least one of the ends of the wear detector device has at least one transverse tab (6, 7) that blocks the brake shoe or pad coupling groove so that, when set in place, the detector is held in place rigidly in relation to the brake shoe or pad. 4. Brake pad or shoe wear detector of preferred application to railway vehicles, according to claim 1, characterised in that the slots (9) for coupling the detector onto the friction material are made on both sides of the slots (8) incorporated into these brake shoes or pads suitable for dissipating the heat produced and removing the traces of friction material detached in them. 5. Brake pad or shoe wear detector of preferred application to railway vehicles, according to the previous claims, characterised in that it is engaged across the whole width of the brake shoe or pad. 6. Brake pad or shoe wear detector of preferred application to railway vehicles, according to the previous claims, characterised in that the central fin (4) of the detector device that comes into contact with the brake disc when the brake shoe or pad friction material is worn down is a continuous fin. 7. Brake pad or shoe wear detector of preferred application to railway vehicles, according to the claims 1 to 5, characterised in that the central fin (4) of the detector device which comes into contact with the brake disc once the brake shoe or pad friction material is worn down is a discontinuous fin made up of at least one ridge.