| 摘要 |
<p>1,202,395. Dash-pots. PIRELLI S.p.A. 17 Oct., 1967 [17 Oct., 1966], No. 47201/67. Heading F2S. [Also in Division H1] A pneumatic dash-pot time delay device for an electromagnetic relay comprises a flexible annular diaphragm 4, Fig. 1, clamped at a thickened edge 15, by a recessed cover 1 forming a chamber 5 with a regulated air inlet 29, the diaphragm 4 also supporting a rigid actuating element 17 by engagement of an inner thickened edge 13 in a groove 14. The element 17 is yieldingly returned during the damped stroke by spring 22. A central port closed by a disc valve 18 under pressure of spring 20 opens during the initial setting stroke to vent the chamber 5. A switch actuating rod 12 is coupled to an inner groove 10 of the element 17 by upstanding flanged lugs 9 and retains the valve spring 20 in position. The electromagnetic armature 44 is coupled to the switch actuator 12 through a single arm lever 49, coupled to a double arm lever 52 at pin and slot connection 51, 56, a spring 58 urging the lever 49 towards the armature 44. In the arrangement shown in Fig. 1 adapted to delay the contact operation on energization of the electromagnet the device is mounted with the actuator 12 engaging the end 59 of the two armed lever, so that on retraction of the armature 44 (as shown) end 59 moves clear of the plunger 12 to permit damped return by spring 22. The device may also be mounted so that the plunger 12 engages the end 60 of the two armed lever 52 whereby the damped movement of the actuator 12 takes place on de-energization of the electromagnet. With this arrangement a cap 47 retaining the return spring 58 is held down by the casing to increase the loading on spring 58 so that it overcomes the loading of the dash pot spring when the arm 49 is urged towards the retracted armature 44.</p> |
