GB813556A - The propulsion of bodies such as projectiles reciprocating members and the like - Google Patents

Abstract

813,556. Reciprocating electric motor; linear motors. RHOKANA CORPORATION Ltd. Dec. 12, 1956 [Dec. 12, 1955]. No. 37926/56. Class 35. The motion of an armature is controlled e.g. for tuyere punching, linear displacement, reciprocatory pumping, or throwing projectiles, by energizing coils 11, 12 in a core having poles 14, 15, 16, in suitable sequence. The armature plunger 18 is provided with a tapered section at one or each end by using non-magnetic conical inserts 48. Pulse switching from one solenoid to the next may be achieved by gridcontrolled mercury-arc tubes controlled by an electric sequence timer to produce a progressive movement or, by means of suitable feedback detection, a determined position, of the armature. The length 38 of the armature is between 1.5D + K and 2D + K, where D is the distance between the poles and K is a constant. A circuit for tuyere punching is shown in Fig. 4 in which the incoming three-phase supply is converted into timed D.C. pulses for coils 11, 12 at lines 50, 51 with a common return 52, by means of two sets of three-phase connected mercury-arc rectifiers in a power unit 72. The power unit is controlled by synchronized triggering pulses from a generator 73 which provides triple frequency incipient triggering impulses generated by a unistable trigger circuit fed with the ripple voltage produced by star-connected three-phase rectifiers. The generated pulses are amplified by triodes which are so biased that they will not conduct the incipient trigger pulses unless a further bias is provided by gating pulses from a timing circuit 74 comprising a conventional trigger ring in which one of the stages is interrupted by a controlling switch controlled by a distribution control circuit 75. This circuit is controlled by manual or automatic devices 76, 77 depending on outside conditions, and serves to switch the supply of pulses from one set of punches to another with suitable delay periods by means of contactors 78. It is described how the switching may be initiated by the back e.m.f. developed in coils 11, 12 fed into the control circuit. Fig. 10 shows the application of the invention to the linear positioning of a plunger 37 by the selective energization of coils 200-203 through mercury discharge tubes 204-207. A series-connected brake 214 locks the plunger in the de-energized conditions. Each tube discharges through a current transformer 210 feeding a delay device 211 by means of which a triggering impulse is provided at the correct time for the next power impulse from a trigger device 208. Ganged switches 212 serve to feed the delayed trigger impulse to the next tube to the left or right depending on which direction motion is required. A similar principle is used in a device for throwing projectiles, the tubes each triggering the next in succession. The armature may be caused to reciprocate and carry valves to act as a pump.