GB290006A - Improvements in or relating to electric motors - Google Patents

Abstract

290,006. Graseby, R. C. March 19, 1927. Oscillating electric motor of high torque, slow speed and small power comprises a spindle 4 mounted between the poles 3 of an electromagnet, a member 6 having cylindrical recesses 7, 8 in its opposite faces mounted on the spindle, a sleeve 17 on the spindle, carrying at one end an armature 18 which swings towards and away from the poles 3 and at the other end a clutch member 9 accommodated in the recess 7 to rotate the spindle when the armature moves in one direction, and a second fixed clutch member 10 in the recess 8 to prevent rotation of the spindle when the armature moves in the opposite direction; springs 22, 23 or a single spring control the oscillation of the armature and a make and break device may be connected in the electromagnet circuit. The electromagnet is suspended by its poles from a brass or other non-magnetic plate 1 which is supported on pillars 2. The armature 18 has an arm 19 carrying a pin 20 to which are attached the springs 22, 23, the other end of the springs being secured to adjustable plates 26, 27 whereby the tensions of the springs can be varied. The armatures also carries a, pin 28 arranged to contact with a spring 29 so as to open the contacts 30, 31 in the electromagnet circuit when the ends of the armature approach the poles. For alternating current, the contact breaker is omitted and the springs 22, 23 are so adjusted that the natural period of oscillation of the armature is equal to or an harmonic of the applied frequency. The clutches in the member 6 comprise balls 11 which are gripped between inclined surfaces on the clutch members 9, 10 and the inner surface of the member 6.