US 2302571 A
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Description (OCR text may contain errors)
NWQ W, 19428 w. i RAY 7 METHOD OF MAKING ELECTRICAL LAMINATIONS Filed Jan. 12, 194!) INVENTOR A TTURNE V Psiente Nov. 37. 384?;
MTE STATEg OFFWE METHOD OF ELIWTRICAL 2 Claims.
My present invention relates to laminations for the construction of cores for transformers and other electrical apparatus.
Such laminations are usually punched from a long rolled band. of transformer iron which, be cause of the method of its manufacture. has a definite grain" wooing in the direction of its length. It has been found that, where such is present, the iron exhibits greater maimetic permeability to the flux lines which are parallel to the direction of. the grain than to those which cross it.
t is, therefore, a main object of my invention to provide a method of cutting iaminations from such a band so that, in the major portions of these laminations, the grain lies in substantially the same direction as that of the path of the flux lines which pass through them when the core, of which they form a part, is energizes.
Another object is the provision of o, method of cutting s shaped laminations from such a band so that the arms oi the so are parallel to the ob rection of the grain.
Another object is the provision of a method of cutting pairs of E and i shaped lsminations from a band of sheet metal so that none of the material is wasted.
Another object is the provision of a method of producing pairs of E and I-shaped iaminetions from a band of transformer iron having a longi tuciinal grain so that the path of the flux lines produced in a core assembled from these parts will be substantially parallel. to the grain in the arms of the E-shapeo. lamination and. in the L shaped lamination.
Gther objects and. advantages of my invention be iouncl in the description, the drawing, and. the appended. claims.
For complete understanding of the invention, reference may be had to the following detailed description and accompanying drawing, wherein:
figures i, 2, 3 and. i are, respectively, plan views of a strip of transformer iron in the positions taken by it in the successive punching operations;
Figures 5 and 6 are plan views of the finished laminations; and
Figure 7 is a sectional view of a transformer assembled from the lamihatiohs and. taken in the plane of one of the pairs of laioiiriations.
In the drawing. the numeral ii indicates a strip oi transformer iron having a longitudinal grain. Broken lines i2, i3 and i4 indicate the positions which the enol of the strip takes prior to the successive punching operations to be per formed on it to produce the laminations.
In Fig. 2, four holes l5 and it; have been punched in the strip. In Fig. 3, two rectangular openings i. have been punched, the removetl (ill.
materiel fOllIlilg' two III-shaped laminations i8 shown Fig. 6. In Fig. 4:, the strip has been out transversely in two places 42 and 2D to form two E-shape i laminations 2 1, shown in Fig. 5; a pressure peel :oreierably being arranged so as to support the end. lei-shaped portion as the doub1e-cut is mode.
The operations described in the precedin paragraph are preferably performed in an automatic punch press and occur simultaneously after the strigo has progressed to the position shown in Fig. e. lit will be noted that no material is wasted, other than that of the bolt holes 15 and In Fig. 7, the broken lines indicate the grain arrangement of the laminations, and lines 22 the general path oi the flux produced in the lamina tions by coil 23. lit will be noted that, other than in the vertical portion of the E-shaped lamination, the direction of the grain is substantially parallel to the path of the flux lines.
While I have described my present invention with reference to a. particular punching process, it is evident that modifications thereof are possible without departing from the spirit of my in vention. For instance, the width of the strip of metal employed may be two or more times the height of the E, a plurality of pairs of E-shaped portions being out off in the final operation. I intend. therefore that my invention be limited only by the scope of the appended claims.
I cleim as my invention:
l. The method of producing a plurality of pairs of E Li..lie.pe:i lamination; for an electrical core which consists in punchlin out from a strip of sheet metal, having a width equal to the height of said E, a pair of I-shapeci portions from the parts of said strip corresponding; to the spaces between the adjoining arms of a pair of opposed iii-shape i portions arranged vertical to the axis of said strip, and then severing said strip transversely across said spaces to form. said pair of i-shaped portions.
2. The method. of producing a plurality of pairs oi F. anti I-shap-eci laminations for an electrical core which consists in punching out from a. band of lamination iron, having a longitudinal grain and a width equal to the height of each of said E and ssici I, e. pair of I-shaped laminations from the parts of an end portion of said band corresponding to the spaces between the adjoining arms of a pair of opposed Esl1aped lamination portions arranged at the end of and vertical to the axis of said band, and then severing said bancl transversely in two places to form said pair of E-shapecl laminations, one of said severing places being across said spaces.
Wm A. RAY.