Patent GB-593274-A (GB)
Title: A machine for performing cutting operations on the commutators of dynamo-electric machines or apparatus
IPC: H01R43/06
Filed: 1945-05-29
Abstract: 593,274. Slotting commutators. LUCAS, Ltd., J., and JONES, D. A. May 29, 1945, No. 13466. [Class 145 (i)] A machine for undercutting the insulating segments of a commutator has the commutator held by a rotatable and axially slidable spindle which has axial movement imparted by cam mechanism, intermittent angular indexing movement by ratchet mechanism controlled by a solenoid and cam, and has a brake for holding it against angular movement controlled by a solenoid, the two solenoids being controlled' by contacts co-operating with the segmental parts of the commutator. The armature spindle e, of an electric motor or dynamo with commutator c, is mounted in a chuck j on the end of a rod m in a hollow spindle i which is rotatable and slidable in bearings f, on the bed of the machine. A rotary cutter r is arranged so that it can undercut one of the insulating strips a of the commutator c during each axial movement in one direction of the commutator with the spindle i, which movement is effected by a snail cam s abutting against a roller carried by a non-rotatable collar u on the spindle. The return movement of the spindle i is effected by springs v or a weight connected to the collar. The cam s is carried by a spindle driven through bevel pinions z from a main horizontal shaft 2 which is driven by an electric motor (not shown). A brake to hold the spindle against rotation comprises a shoe 5, carried by a lever 6 on the bearing g, which bears, under the action of a loading spring 7, against a collar 8 secured to a rotatable but axially immovable sleeve 9 on the spindle i, the lever 6 being connected to the plunger of a solenoid 11 which when energized moves the lever 6 to release the brake shoe 5. A ratchet-wheel 14 is secured to the sleeve 9 and a lever 15, pivoted on the spindle, carries a pawl 16 for transmitting intermittent angular indexing movement to the wheel, the lever 15 being actuated by a solenoid 19. A cam 20 on the main shaft 2, shaped as shown, regulates the rate of movement of the lever 15 by the solenoid 19 and effects the return movement of the lever. The two solenoids 11 and 19 are connected to a pair of electrical contacts 23, 24, Fig. 6, carried by a member 25, which bear on the commutator segments b and, the circuit being complete, indexing movement is imparted to the' spindle by the solenoid 19 until the contact 24 is on an insulating strip a, when the circuit is interrupted, so that the brake shoe 5 is reapplied. A cam 29 on the main shaft 2 then, through the lever arms 28, 26, causes the contacts 23, 24 to be moved to an unobstructive position during the cutting operation, at the close of which the cam 29 allows the contacts to return, the contact 24 now touching the edges of segments b either side of the removed strip to reclose the circuit. When all the insulating strips have been undercut, another cam acts on a control switch to stop the machine. Instead of the contact 24 reclosing the circuit, a switch may be used with contacts in parallel with the contacts 23, 24. Control switches may be provided for the operator. Specification 548,543 is referred to.