GB467199A - Improvements in or relating to electro-magnetically operated reciprocating devices - Google Patents

Abstract

467,199. Electromagnetic interrupters. SANDERSON, E. P., and AMAL, Ltd. Dec. 12, 1935, Nos. 34528 /35 and 30585/36. [Class 38 (v)] [Also in Groups XXVIII and XXXV] An electromagnetically operated reciprocating device for use in pumps, hammer mechanisms, &c. comprises a reciprocating member, a main solenoid adapted to actuate said member, a make-and-break switch included in the main solenoid circuit one contact of which is operated by the reciprocating member, an auxiliary control solenoid connected either in series or in parallel with the main solenoid and controlled by said make-and-break switch, the control solenoid being adapted to keep the make-andbreak switch closed during part of the positive or forward stroke of the reciprocating member, a stop or the like acting to open the make-andbreak switch near the end of the forward stroke, and a spring or like means keeping the make- and-break switch open during the return stroke. As shown in Fig. 2 of the first Provisional Specification the main electromagnet 3 is mounted on a core 2 through which passes a rod 17 carrying a main armature 4 at its lower end and at its upper end an auxiliary solenoid 21 connected in parallel or in series with the main solenoid. Secured to the upper end of the rod 17 is a contact 27 normally engaging a contact 29 attached to an armature 30 carried by a blade spring 31 and when the circuit of the electromagnets is completed, during the first upward movement of the rod 17 the contacts 27, 29 travel upwardly together owing to the attraction of the armature 30 by the auxiliary electromagnet. At or near the end of the stroke of the rod 17, however, the end of the armature 30 engages a stop 36, which may be adjustable and the rod 17 by continuing its upward movement owing to the inertia of the moving parts, separates the contacts and breaks the circuit of the electromagnets. The armature 30 then springs back rapidly to the position shown causing a rapid separation of the contacts, the rod 17 being returned by the spring 39. Thus contact is not re-made until the armature has completed its return stroke. The contact separation is made in the field of the auxiliary electromagnet which thus has a magnetic blowout effect and a spark-reducing condenser may be connected across the contacts. The windings of the main and auxiliary solenoids are so made that the reverse induced voltage set up by the latter prevents the building up of a high-sparking voltage. The armature 4 as shown is attached to the operating diaphragm 5 of a fuel pump with inlet connection 8, gauze filter 12, pumping chamber 9 and non-return or ball outlet valve 14. In a modified driving arrangement the auxiliary solenoid is made stationary, the relatively fixed interrupter contact being mounted on an armature adapted to be attracted to this solenoid during a portion of the upward stroke of the main armature.