Patent GB-1166592-A (GB)
Title: Method and Apparatus for Forming Electric Motor Armatures
IPC: H02K15/04
Filed: 1968-02-05
Abstract: 1,166,592. Making armatures; punching. PHOTOCIRCUITS CORP. 5 Feb., 1968 [6 Feb., 1967], No. 5613/68. Headings B3A and B3W. A method of making conductor patterns for electric motor armatures comprises indexing a metal blank 90 through a predetermined number of punching positions, punching the blank at each of the punching positions to form an armature conductor pattern by removing the metal between adjacent conductor segments, punching at least two alignment holes in the blank while at selected ones of the stamping positions, the holes being at the same radial distance from the centre of the conductor pattern and located in the scrap area outside the conductor pattern. The blank 90 is indexed by a drive 60 driven by a motor 63, which also drives a punch rod 61 and a programme drum 64. The drive 60 is geared to a shaft 72, which is provided with spurs 93 which dig into the blank to provide a positive engagement, the upper surface of the blank being engaged by a clamp member 91. This member comprises a pressure shoe 92 forced downwardly by a pneumatically actuated thrust rod 83, which has a conically hollow end 94 centred in the shoe 92 by four springs 99. The thrust is transmitted by a rod 96 which engages a plate 97 mounted on bearings 98 so that the shoe rotates precisely about the same axis as the drive shaft 72. On a punching stroke the movable portion of the die set moves downwardly until a stripper plate 73 engages the blank 90 and a downwardly extending portion of a punch 74 passes through an opening (113) in the plate 73 into a corresponding opening (84) in a die plate 71, Figs. 7, 8 (not shown). Simultaneously a spring-loaded punch 75 moves downwardly in a guide sleeve 120, the spring pressure not being sufficient to cause the punch to pass through the metal of the blank. When the punch 75 is required to form an alignment hole in the blank an interference plate 124 is moved to the position shown in Fig. 8 to engage the top of the punch 75 and force it through the blank during a punching stroke. The programme drum 64 has pins 140 corresponding to the stamping positions at which alignment holes are to be punched. These pins actuate a microswitch 141, which in turn actuates an air cylinder 132 to advance the plate 124 by a pressure plate 130 attached to the press by a linkage 131. Lines passing through the alignment hole centres form an isosceles trapezoid, the centre line of the trapezoid forming a datum or flip-line (24), Fig. 1B (not shown). One stamping is rotated 180 degrees about its flip-line, which is aligned with the flip-line of a second stamping and the stampings are bonded to a dielectric carrier 16. The scrap material 15, 14 at the periphery and centre of the conductor patterns is removed to expose the connection tabs, which are then welded together to complete the winding. Fourlayer armatures may be similarly made. The winding of a two-layer winding is preferably of wave configuration and where more than two layers are used two of the layers are preferably in wave configuration and the remainder in lap configuration.