| 摘要 |
<p>A pressure switch for a compressor or similar apparatus which can supply a fluid under pressure and is driven by an electric motor, comprises a support structure (1), a diaphragm (4) which is fixed to the support structure (1) and is intended to be exposed to the pressurized fluid, electrical contacts (9, 10, 11, 12) mounted on the support structure (1) and arranged for movement towards and away from one another between a position of closure and a position of opening of an electrical-supply circuit of the electric motor, a manually-operated control member (3) movable between two positions in which the electrical contacts are in the positions of opening and of closure of the electrical circuit, and a lever mechanism (14) operatively associated with the diaphragm (4) and with the electrical contacts in a manner such that, when a pressure above a predetermined threshold value is applied to the diaphragm, the lever mechanism brings about movement of the electrical contacts to the opening position, and is characterized in that it comprises a temperature-sensitive thermal cut-out (17) which is mounted on the support structure (1), in series with the electrical supply circuit of the motor, and is arranged to open the electrical-supply circuit automatically when the temperature exceeds a predetermined value, the cut-out being operable manually in order to be reset to a closure position which is stable when the temperature is below the predetermined value, and the cut-out being operatively associated with the control member (3) in a manner such that the cut-out is reset to its closure position as a result of the movement of the control member to its position which brings about opening of the electrical contacts.</p> |
