US1589464A - Insulating ring and method of making the same - Google Patents

Description

June 22 1926. 1,589,464

- L. T. FREDERICK INSULATING RING AND METHOD OF MAKING THE SAME Filed June 7, 1924 c [02:03 reaerzdf Patented June 22, 1926.

UNITED STATES 1,589,464 PATENT OFFICE.

LOUIS '1. FREDERICK, OI VALPABAIBO, INDIANA, ASSIGNOR T0 CHICAGO IIOA 0O!- PANY, OI VALPARAIBO, INDIANA, A CORPORATION 01 ILLINOIS.

' mlULA'1ING RING AND METHOD 0] MAKING THE an Application filed June 7,

M invention relates to insulating bodies of t c class used,-for example, in electric motors and generators to insulate various parts of the apparatus from each other. My invention relates particularly to insulating bodies having annular flanges of various shapes and the object of the invention is to produce a body of this character which shall be eflicient as an insulator and at the same time possessed of a. high degree of strength and uniformity of structure. My invention is especially useful in connection with the formation of insulating bodies or rings formed of mica plate. Mica plate is a known article and consists of mica flakes held together by shellac or other suitable binder. It is plastic when hot and may be configurated by subjection to heat and pressure. It is known to form rings from mica plate, but according to methods heretofore employed the flanges have not been of uniform strength or consistency throughout their ri hery. The flanging rocess has cause a istortion in the material and frequentl the mica has been crushed toa perceptib e degree, thus 'weakening both its structural and its di-electric properties.

My purpose is to obtain a simple and re-.

liable method by which these imperfections may be avoided and a ring of uniform strength produced free from internal stresses and strains and of uniform consistency.

I accom lish my object in the manner illustrated in the accompanying drawings in which Figure 1 shows three discs of mica plate or similar sheet material from-which a ring may be produced. These are shown with slots in their periphery and are separated for the purpose of showing their outline.

Figure 2 1s a view similar to Figure 1 but showing the sheets superposed in contact with each other.

Figure 3 is a perspective pleted ring.

Figures 4, 5 and 6 are diametral sectional views of difierent configuration.

Like numerals denote like parts throughout the several views.

In practicing my process I first produce the sheet material,- referably mica plate composed of flakes o mica held together by she ac or other suitable binder. This sheet material is plastic in the sense that it can view of a com- 1924. Serial No. 718,481.

be configurated when hot. From this sheet material I produce a number of blanks, typical ones of which are shown in Figure 1 and indicated by the reference numeral 1. In the case illustrated they are circular in outline and have radial slots 2 cut in their peripheries at spaced intervals. Usually .these slots are in the form of sectors arranged radially although their sides may or may not be exactlg radial, this depending upon the shape of t e flange ultimately. de'.

sired. Ordinarily the an le will be such that when the flange is nally formed the tongues or. dovetails will "come edge to Y edge or approximately so. 'l-.he-sheets thus prepared may be referred tojas the'blanks.

'After they areformed," the blanks to a predetermined number are laid one upon another in stag Figure 2, that 1s, they are superposed in such a manner that the slots are out of register and the slots of one sheet will come opposite to the blank portions or tongues 3 of the adjacent sheet. I The pile of blanks thus arranged is then subjected to the action of a drawing die. Mica plate is plastic when hot and the die may be heated if desired, but I have found that by preparing and arranging the blanks in the manner described, excellent results may be obtained by heating the blanks beforehand and inserting them while hot into a cold die. By this method the material' is already plastic before reaching the die and the die, being cool, will rapidly configurate the material and promptly cool it. This greatly increases the output over the amount that could be obtained by employing a heated .die. In either case the pressure of the die not onl configurates the material but also binds t e laminations into a sin le unitary structure. Apparently the bin er is forced from the body of the mica sheets partly onto the surface of the sheets and being hot thus cements the sheets together. In the finished article the laminations are not apparent and the article has the appearance of a solid close knit structure.

A suitable die may be made in different ways and its configuration will depend upon the configuration desired in the ultimate product. In Figures 4, 5 and 6 I have shown finished products of diiferent form. The form (1 shown in Figure 4 is frequently denominated in the trade a V ring that red relation as shown in.

shown in Figure a Z ring and that shown in Figure 6 an L ring. While elec tric motors and generators usually require rings in which the central portion. is cut awa it will be evident that the same met 0d may be applied to the production of cup shaped or plain dished bodies, the

central portion first, as the ortion removed can then be used for pro uoing rings of smaller sizes.

It will be evident by referring to Figure 3 that the finished ring when made' in accordance with the preferred proportions will have a flange 5 in which the tongues 3 are closed up in the sense of having their edges substant ally in contact with each other and the flanges will be composed of a plurality of layers of tongues which overlap each other. Thus the ring may be said to have a composite butt and lapped flange.

Rings produced in this manner possess remarkab e strength and uniformity structurally and uniform'insulating properties It will be evident that the mica in the flanges is configurated without being crushed or distorted. Mica has a crystalline structure and if. subjected to undue pressure or stress of any kind will tend to crush. Such crushing occurs where the flanges are not notched and are configurated by a mere drawing,

and the ring is formed of a single sheet instead of a pluralityof thin superposed sheets. In bodies produced by my process and having laminations of mica sheets with butt and lapped flanges there is no distortion nor. 'crushing and the finished articlel is stripng and of uniform properties throughon While my invention is especially applicable to mica plate it is not necessarily confined thereto for other plastic sheet material may be employed. For example, the sheet material may consist of canvas or other woven fabric impregnated with a binder other than shellac, for example, condensation product sometimes called synthetic resin and produced by reacting formaldehyde and phenol in the presence 01% a reaent. It is known to produce hard bodies y subjecting to the action of heat and pressure layers of woven fabric saturated in such condensation product and I may apply the prlnclple of my invention either to mica sheetsor to woven fabric saturated in such condensation product. In using condensatron product as a binder, however, a subse- -material to permit configuration of the sheet without distortion.

2. An insulating body having an annular flange and composed of a plurality of laminations of plastic sheet material, each sheet having sector shaped slots to permit the flange to be formed Without distortion and the slots being staggered to produce a lap- 3. An insulating ring having a central opening and an integral flange, the ring being composed of circular, concentric laminations of mica plate and the flanged portion being of butt and lapped construction.

4. The method of making insulating.

bodies consisting in taking a plurality of layers of circularmica sheets piling them concentrically and subjecting them while hot to the action of a drawing die.

5. The method of making flanged insulating bodies consisting of preparing a plurality of sheets of plastic insulating material having radial slots in the periphery, staggering the sheets so that the slots shall be out of register, and subjecting the pile of sheets while hot to the action of a drawing dieto' produce a flange from the slotted portion of the sheets.

6. The method of producing flanged in- I sulating bodies consisting in preparing a plurality of blanks of plastic insulating material, cutting notches in the periphery of the blanks, arranging the blanks in a pile with the notches out of register, heating the blanks to render them plastic, and subjecting the pile of blanks while in plastic condition to the pressing action of a drawing die to thereby produce a lapped flange and simultaneously unite the blanks to each other. I

7. The method of producing flanged insulating bodies consisting in preparing a plurality of circular blanks of mica plate, cutting sector shaped slots at spaced intervals in the periphery of the blanks, arranging the blanks in a pile with the sectors out of register, heating the material to render it plastic, and while the material is plastic forming an annular flange in the pile of blanks to an extent which will cause the dovetails between sectors to meet edge to edge.

8. The method of producing insulating rings consisting in preparing a plurality of circular blanks of mica plate, cutting sector sha (1 slots at s aced intervals in the perip cry of the b ank, arran g the blanks in a pile with the tongues etween sectors overlapping each other, heating the material to render it plastic, and while the material is plastic forming an annular flan e in the ile of blanks to an extent which will causet he tongues to close up, substantially edge to edge, and chilling the material simultaneously with the forming operation.

9. The method of roducing insulating rings and the like consisting in making thin sheets composed of mica flakes and a binder capable of becoming plastic when heated, preparing circular blanks from said sheets,

LOUIS T. FREDERICK.

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