US1241578A - Electric heating apparatus. - Google Patents

Description

F. THORNION, In,

ELECTRIC HEATING APPARATUS.

APPLICATION FILED APII. I2. I9I5\ 1,241,578. PaIenIed Oct. 2, '1917.

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4 BY www ATTOFIINEY F. THORNTON, JA.

ELECTRIC HEATING APPARATUS.

APPLICATION FILED APR. i2. |915- Pamented Oct 2,1917.

2 SHEETS-SHEET 2 WITNESSES N, wm T0 Nf we mM H, m f F ATTORNEY I lNlTED STATES PATENT FFGE.

FRANK THORNTON, JR., OF PITTSBURGH, PENNSYLVANIA, AS-SGNOR T0 'WESTINGK- H'SE ELECTRIC AND MANUFCTURNG COM?ANY, A CAORPORATON 0F .'ENNSYL- ELECTRIC HEATXNG APPARATUS.

Application e April 12, 1915.

To all whom 't may concern.'

Be it known that l, FRANK THORNTON, Jr., a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electric Heating Apparatus, of which the following is a specification.

My invention relates to electric heatlng apparatus and it has special reference'to heating devices of the radiant type in which a heating element is mounted upon a support of insulating material in contact with the air to impart its heat by radiation.

The object of my invention is to provide a simple and inexpensive method of mounting conducting wires or ribbons upon insulating supports.

More specifically, the object of my invention isto provide a method of mounting resistance elements upon insulating sheets formed of fragmentary insulating material, such as flakes of mica, and a further object of my invention is to provide a radianttype electric toaster stove having a heating element constructed in accordance with the method indicated above.

In the accompanying drawings, Figure 1 is a side elevational view of a toaster stove constructed in accordance with my invention. Fig. 2 is an end elevational View of the device shown in Fig. 1 taken from vthe right of Fig. 1, and F 1g. is a transverse central sectional view of the same device.

The device shown on the drawing consists .of arectangular heating plate 1 mounted in a substantially vertical position in a frame composed of end pieces 2 and 3 joined by a top plate 4 and a bottom plate 5, the end pieces 2Q and 3 being bent outwardly and downwardly to form supporting legs l6. The bottom plate is curved downwardly, as shown in Fig. 3, to form a crumb collector. llVires 7 are disposed on both sides of the heating element 1 and are bent into the form shown for the purpose of supporting slices of bread or the like to be toasted. The ends of the wires 7 may be received in perforations in the bottom plate 5, and the bent centralportions of the wires are supported in clamps formed by cutting slots in the top plate 4 and bending the cut por- Spec'eatlon of Letters Patent.

Fatented Got. tt?.

Serial No. 20,895.

tion of the metal into ears 8 and 9. A metal fastened to the top plate 4 by means of rivets 11. A terminal block holder 12 is riveted to the end plate 3 andcontains a terminal block 13 of any suitable form. The holder 12 is formed into a receptacle 14 adapted to receive a terminal block 15.

The structural details thus far described are merely illustrative and are not essential to my invention, which is concerned particularly with the structure of the heating element 1. This element is composed of a rectangular metal frame 16 provided with ears 17 at its-four corners which are adapted to project through openings in the end pieces 2 and 3 of the toaster frame. A rectangular plate 18, composed of built-up mica flakes, is mounted in the frame 16 and is provided with spaced rows of perforations 19 through which is passed a resistance wire or ribbon 20, the ends of which are led to the terminal block 13 through a oord 21.

lt will be observed that three transverse rows of resistance v'strips are provided on each side of the plate 18 and that the lowest row of the three consists of a greater number of strips than the two upper rows. This is a desirable arrangement because it affords increased heat-radiating capacity adjacent to the lower portions of 'the slices of bread that may be supported on the rack formed by the wires 7, which portions ot the bread are farther away from the heating element than the upper portions.

ln making the heating element, a composite plate is iirst formed from small Hakes of mica held together by a bonding material that can subsequently be driven cti by heating. This composite plate is mounted in the frame 16 and perforated in the manner shown, and the resistancewire or ribbon is :around on 'the sheet of mica b lacing it through the corresponding pertorations in the several rows. The plate is then heated to a suiiicient temperature to evaporate the bonding material, leaving the heater consisting only of the mica and the resistance material. The method of winding the resistor by lacing it through the holes results in holding the smallpieces of mica in their proper positions after the bonding material has been driven 0H. In all similar structures that have heretofore been devised, it has been necessary to provide solid sheets of natural mica of the necessary area, and such sheets are relatively expensive. It Will be evident that my method of mounting resistors, in which the resistor is supported by the composite insulating material and also serves to hold the. insulating material in its assembled position, results in a considerable saving in expense.

The principles of my invention may be applied to many forms of devices other than radiant toaster stoves, and it is also to be understood that fragmentary insulating mate rial other than mica may be used Within the scope of my invention. I desire, therefore, that no limitations be imposed upon my invention unless indicated i in the appended claims.

I claim 'as my invention:

l. The method of mounting electric conductors upon insulating supports that comprises uniting a fragmentary insulating material into a: coherent structure by means of a binder, mounting a body of conducting material on the said structure, and removing the said binder.

2. The method ofmounting electric conductors upon insulating supports that comprises uniting flakes of mica into a coherent structure by means of a binder, mounting a body of conducting material on the said structure and removing the said binder.

3. The method of mounting electric conductors upon insulating supports that com prises uniting Hakes of mica into a coherent structure by means of a binder, mounting a body of conductingmaterial upon the said structure in such a manner as to hold the flakes together, and removing the said binder.

4. `The method of mounting electric conductors upon insulating supports that comprises forming a composite sheet of a fragmentary insulating material and a binder, perforating the said sheet, passing a body of conducting material through the perforations in the said sheet, and removingthe said binder; Y

5. The method of mounting electric con duetors upon insulating supports that comprises forming a composite sheet Vof mica Hakes and a binder, perforating the said sheet, passing a body of conducting material through the perforations in the said sheet, and removing the said binder. v

6. The method of mounting electric conductors upon insulating supports that comprises forming a composite sheet of mica flakes and a hinder'that can be subsequently removed by heat, perforating the said sheet, passing a body of conducting material through the perforations in the said sheet, and heating the resulting structure to remove the said binder.

7. The process of making resistance devices for electric heating apparatus and the like that comprises forming a composite sheet of a fragmentary insulating material and a binder, forming a plurality of spaced perforations in the vsaid sheet, passing a resistance Wire through the said perforations in such a manner that the resistance wire is supported by the said sheet and also serves to maintain the fragmentary material in its assembled position, and removing the said binder.

8. The process of making resistance devices for electric heaters and the like that comprises forming a composite sheet of mica Hakes anda vaporizable binder, forming a plurality of spaced perforations in the said sheet, passing a resistance Wire through the said perforations in such a manner that the resistance wire is supported by the said sheet and also serves to maintain the mica Hakes in their assembled position, and applying heat to volatilize the said binder.

9. The process of making resistance devices for electric heaters and the like that comprises forming a composite sheet of mica Hakes and a binder, forming a plurality of rows of perforations 1n the said sheet,

passing a resistance Wire back and forth through the corresponding perforations in the said rows in such a manner that the resistance wire is supported by the said sheet and also serves to hold the said mica Hakes together, and removing the said binder.

10. An electric heating device comprising a composite structure of fragmentary insulating material held in assembled position by means of a resistance element, the said resistance element being supported upon the said structure and extending therethrough in a plurality of convolutions.

11. An electric heating device comprising a sheet composed of mica flakes held t0- gether by means of a resistance element supported upon the said structure and extending therethrough in a plurality' of convolutions l2. An electric heating device comprising a composite sheet of mica flakes rovided with av plurality of rows of perforations, and a resistance Wire extending back and forth through the corresponding perforations in the said rows in such manner that the said resistance Wire is supported by the said sheet and also holds the said Hakes together.

13. A radiant electric toaster device comprising a frame, a radiant resistance device supported therein and a terminal device for supplying energy to the said resistance device, the said resistance device comprising a composite sheet of mica Hakes provided with a plurality of rowsof perforations and a remerma S sistance wire extending back and forth resistance conductor extending through perthrough the corresponding perforations in forations in the sheet and supported thereby l@ the said rows in such manner that the said to present radiating surfaces on both sides resistance wire is supported by the said sheet of the said sheet. 5 and also holds the said flakes together. In testimony whereof, I have hereunto sub- 14. An electric heating device comprising scribed my name this 30th day of March, n frame, a sheet of insulating material sup 1915.

ported vertically by the said frame, and a FRANK THORNTON, JR.

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