Brush holder for an electrical collector machine, particularly for a direct current motor

Brush holder for an electrical collector machine, particularly for a direct current motor, comprising

• an electrically insulating support structure having a central aperture for the passage of the collector, around which retaining and guiding cases are fixed, a corresponding positive or negative brush being mounted in an axially translatable way in each of said cases, with one end of the brush bearing on the collector in operation;
• the support structure comprising a body of moulded plastics material incorporating at least a first and a second essentially rigid conducting element connected, respectively, between the positive and negative brush or brushes and associated connecting means, so as to form corresponding connecting paths in the brush holder for connecting the brushes to the terminals of an external source of supply voltage;
• at least one discontinuity being provided in at least one of the said connecting paths, a resiliently deformable and electrically conducting strip being connected mechanically and electrically across the said discontinuity, with a substantially permanent connection at one end, and with a thermally fusible connection at the other end, the strip also having a resilient pre-loading which tends to break the connection at the said other end.