ARMATURE LAMINATIONS 



adjacent slots at a time), a linger die is employed. One form is 

 described by Brunswick and Aliamet by means of a sketch, which 

 we reproduce in Fig. 33. The principal parts to which we should 

 direct our attention are the punch, P, and the die, D. The punch, 

 P, is of equal section throughout its length ; but the die, D, diverges 

 so as to avoid wedging, while at the same time permitting of a very 

 exact fit at the upper surface 

 on which rests the plate to be 

 punched. Frucht recommends 

 that, in order to make a clean- 

 edged cut, the punch should be 

 smaller than the size of the slot 

 to be cut, to the extent of one- 

 eighth of the thickness of the 

 plate, and that the aperture in 

 the die should be an equal 

 amount larger than the size of 

 the slot to be cut. The illus- 

 tration in Fig. 33 relates to the 

 so-called French type, which is 

 characterised by the guiding of 

 the punch, P, by means of the 

 guide, G. The plates must be 

 inserted between the lower 

 surface of G and the upper 

 surface of the die D. This 

 type is inconvenient as regards 

 the less ready manipulation of 



,, , . . ,, , . , , FIG. 33. Detail of Punch and Die. 



the plate in the restricted space 

 between G and D, but it affords 

 a very exact guidance to the 

 punch P, right close down to 

 the surface to be punched. A 

 slight modification of the so-called " French " type is shown in the 

 punches of Fig. 34, where will be seen at the side of the punches, 

 and mounted rigidly with them in the same blocks, guiding rods so 

 designed as to ensure exactness in the movement of the punch, thus 

 avoiding the necessity for passing the punch itself through guides. 

 The alternative and generally preferred method, employs the 

 so*-called " German " type. In this type the punch is short, and 

 after having perforated the plate, does not pass an appreciable 

 distance beyond. As applied to a compound die, the construction 



M. Connecting-rod for Driving. 

 B, B, Guide of Slide Block C. 

 N, Punch Holder. 

 P, Punch. 

 D, Die. 



G, Guide of Punch. 

 H, Bed of Punching Machine. 



