Patent ID: 6971168

Claim:
A method of manufacturing a valve plate to be interposed between the cylinder and the output manifold head of a compressor, which plate ( 36 ) has a pair of openings, that is, an output opening ( 48 ) and an intake opening ( 80 ) for cooperating, respectively, with an elongate, resilient output closure blade ( 54 ) and with an elongate, resilient intake closure blade ( 84 ), which are situated on opposite faces of the plate and each of which has one end cooperating with the respective opening and another end fixed to the plate, and in which plate ( 36 ) a depression ( 42 ) is formed at least in the face which is to face towards the compressor head, the depression ( 42 ) having a profile shape which substantially corresponds to that of the output closure blade ( 54 ) and in the base of which the output opening opens, towards one end of the depression ( 48 ), characterized in that the method also comprises at least the following steps in succession: blanking a blank of the plate ( 36 ) from a steel sheet of suitable thickness, punching holes corresponding to the output and intake openings, the hole corresponding to the output opening being a preliminary hole ( 48 a ) having a diameter larger than the final diameter of this opening ( 48 ), forming, by coining, the depression ( 42 ) for housing the output closure blade ( 54 ), with the depth of the depression increasing towards the end of the depression which corresponds to the preliminary hole ( 48 a ), in a manner such that, during the coining, at least some of the material of the blank creeps towards the preliminary hole, partially filling it, calibrating the output opening ( 48 ) to the final diameter by punching, and coining an annular projection ( 50 ) around the calibrated output opening ( 48 ) to define a valve seat for the output closure blade ( 54 ).