US1127741A - Process for making terminal banks. - Google Patents

Description

UNITED STATES PATENT OFFICE.

AMOS F. DIXON, OF NEWARK, NEW JERSEY, ASSIGNOR '10 WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

PROCESS FOR MAKING TERMINAL BANKS.

Specification of Letters Patent.

Application filed February 26, 1912. Serial No. 679,945.

To all whom it may concern:

Be it'known that I, Amos F. DrxoN, citi-' zen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvement in Processes for Making Terminal Banks, of which the following is a full, clear, concise, and exact description.

This invention concerns selector switches such as are used in automatic telephone exchanges, and has to do particularly with the process of making the terminal boards thereof, that is, the boards which carry the multipled line terminals.

In constructing terminal boards composed of alternate layers of sheet-metal and insulation, great difliculty is encountered due to-the variations 1n thickness of the insulating sheets and of the sheets of metal. Since these variations are cumulative, 1t

.becomes impossible to stack up any considerable number, one above the other, so

that the centers between terminals and consequently also the overall dimension will be at all uniform. It can be readily appreciated that if the rubber or mica or other insulating material should vary even, say, half a thousandth of an inch, by the way a small commercial variation, the cumulative variation on such a mass of terminals as used on an ordinary board would be'very great and make successful construction well nigh impossible. The present invention overcomes this difiiculty and enables the production of a cheap and efficient terminal board.

Considered broadly, the invention consists in the process of superposing sheets of flexible insulating material, such as paper, coated .with a plastic insulating compound, and sheets of terminal forming metal, and applying pressure to the resulting structure until the. overall dimensions are reduced to the desired amount. It is a peculiarity of this process that, in the finished product so formed, not only may the overall dimen sions, be regulated with extreme nicety, but

- the distance between the individual strips is equally and uniformly reduced to the required figure. I may use a compound which is originally sufiiciently plastic for the purpose, but which dries and hardens when exheat and which hardens sufiiciently to maintain rigid the terminal sheets when allowed to cool. It is desirable that the compound be non-hygroscopic and have first-class insulating qualities; also that these qualities be stable. I

In the drawings, Figure, l is a front elevation of a portion of the completed terminal bank; and Fig. 2 is a perspective view of the superposed sheets during the process of assembly.

Referring to the drawings, 10 designates a punchingof sheet metal preferably having ears or lugs adapted to form the contact terminals t 25 The cars upon each metallic strip form multiple terminals of the same line on both faces of the board, so that each line is accessible to every brush on both sides of the board. A line may have but a single terminal t or may consist of what are known in telephony as the tip, ring and sleeve terminals, 27, 25 t. Attention is called to the peculiar formation of the .a manufacturing stlindpoint, wire may be substituted for the sheet metal. The sheets of metal after being punched into shape are stacked up alternately with paper coated with an insulating compound which is or mav be caused to become plastic.

Paper, as is well known is one of the few substances which can be manufactured in sheets which vary but little in thickness. It is also afirst-class insulator. Therefore I prefer to use paper as a base for the insulating compound.

A very desirable compound may be made from elaterite fused with linseed oil, but it is of course understood that any equivalent compound may be used without de arting from the scope of the invention. The resultant insulating elements consisting of the paper sheet and its compound are then stacked up alternately until the desired number of terminals is obtained. A convenient method of doing this is shown in Fig- 2 andconsists in perforating the metal sheets 10 and insulating elements 11 and threading themupon sleeves 12, 12' of insuioo - the required number has 4 top plate 18 is secured in place. As many v is removed, the nuts 'lation slipped over the rods 13, 13 secured at their lower ends to the base 18, and when been built up, the

bolts 13 and their sleeves are provided as may be necessary. The resultant structure is then placed between heavy iron clamps, (not shown) and heated so that the insulating compound becomes somewhat viscous,

and pressure is applied by means of the amount of compression to insure the proper overall dimensions and consequently the proper distance between individual sheets. They are provided with 111115921, 21ai1d 16, 16 respectively; The heating process may thenbe" discontinued; The compound there; upon hardens and the is then removed 1 sheets coated with from the clamps a solid, homogeneous mass" having uniformly-spaced, projecting lugs. 4

I claim z 1. The process of makin terminal boards consisting of superposing exible insulating sheets coated with a plastic insulating compound and metal strips, and subjecting the structure thus built up to pressure.

2. The process of making terminal boards consisting in superposing flexible insulating pound and metal having projecting lugs, and subjecting the structure thus built up to pressure.

a plastic insulating com- 3. The process of making terminal boards consisting in superposing in alternate layers, sheets of paper coated with a plastic insulatcompound and sheets of metal having projecting lugs, subjecting the structure thus built up to pressure in the presence of heat to uniformly space the terminal sheets, and finally allowing same to cool.

In witness whereof, I, hereunto subscribe my name this 24th day of Feb. A. D., 1912.

AMOS F. DIXON. Witnesses:

- IRVIiIG MAc-Do unn,

WAL ER F. HOEEMAN.

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