US905045A - Electric heating device. - Google Patents

Description

J. I. AYER & H. B. GALE.

ELECTRIC HEATING DEVICE. APPLICATION FILED JUNE 13,1908.

Patented Nov. 24, 1908.

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8 Ii pg V 16%06656/6. W AM JAMES I. AYER, OEF CAMBRIDGE, AND HOR ACE B. GALE, OF NATIGK, MASSACHUSETTS,

ASSIGNOBS 'lO SIMPLEX ELECTRIC HEATING COMPANY, OF CAMBRIDGE, MASSACHU- SETTS.

ELECTRIC HEATING DEVICE.

Specification of Letters Patent.

Patented Nov. 24, 1908.

Application filed June 1a, 1908. Serial no. 438,299.

To all whom it may concern:

Be it known that We, JAMES I. AYER and Homer B. GALE, citizens of the United States, and residents of Cambridge and Natick, respectively, both in the county of Middlcsex and State of Massachusetts, have invented an Improvement in Electric Heating Devices, of which the following descrip tion, in connection with the accompanying drawings, is aspecification, like letters on the drawings representing like parts.

Our invention is an improvement on the primary invention set forth in 00- ending application Serial No. 438,103 filed une 12, 1908, in which the general purpose and nature of the invention are set forth, the present improvement having for its object the still further increase of heating capacity and uniform distribution of the heat, for a given weight or size of apparatus.

Stated in general terms, this type of invention consists of so disposing the resistance wire withrelation to the heat receiving or absorbing surface, which is parallel to the'plane 0 the resistance wire or ribbon, as greatly to increase the available surface area both of the resistance medium and of the heat-absorbing medium over that which is ossible when the resistance medium'is lai flat upon a single plane or horizontal heat-absorbing surface, in the manner common in electrically heated tools and apparatus.

The desired result is secured by standing at ribbon-like layer of resistance wire or the like on edge substantially perpendicularly to the general plane of the heater, the latter being provided with corresponding grooves in which the edgewise-standing resistance 40 wire is immovably secured by vitreous enamel fused to the --iron or metal constitutmg the heat-absorbing medium and also fused about the wire, thereby holding the latter in'an extended flat layer or plane ver and yet a very much tical to the main body of the iron and yet parallel to the heat-absorbing surfaces or walls of said grooves. By maintaining this extended 'flat layer of resistance medium thus parallel or at'a uniform distance at all points from the heat-receiving surface, a uniform rate of absorption of heat is insured ater length of heating unit is made ossi le, so that less stress or strain results or a given length of wire, inasmuch as the desired temperature of the tool is maintained through the agency of a much longer resistance wire than before. Inother words, for a given mass of heat absorbing and conveying plate or tool, the

samequantity of heat as before is derived from a greater length of the resistance wire than before, and hence the latter is subjected to less strain inasmuch as there is obviously a lower temperature per given length of wire, and yet notwithstanding thls fact there is no irregular. heating of the wire (such as would occur if the wire were wound in a coil or in any form which would place any part of the wire further from the plate than any other part) because all portions of the laterally extended or ribbon-like layer of said wire are at practically the same distance from the heat-receiving and absorbing 7 surface of the plate. 0

Our present improvement consists in arranging the widely extended ribbon-like layer of resistance wire or current-conveying medium in a reflex form, 2'. e. in a V shape or U shape, viewed in cross section, the receiving grooves of the plate being correspondingly shaped, and the intervening ribs or projecting portions of the plate having their sides or heat receiving and absorbing surfaces arranged parallel respectively to the adjacent sides of the reflex windmg of wire. By this means we secure the advantages of the main invention with 1ncreased efliciency of results.

Our invention also has advantages of manufacture, durability and use.

.view showing the coverin layer of enamel applied, thereby immovaby embedding theresistance in operative positlon; F 1gs. 6 and 7 are plan and end views respectively of a ribbon of resistance wi're bent flatwise; Fig. Y

8 being an end view of the same reflei red or bent into V shape, according to our inven- 1 and retain thus in proper operative position the conductor which is to I venient type of this general classof electrically heated tools and devices, and accordingly it will be understood tha' I this 'ispresented merely as a type and that it does not limit the invention in any way. This block' or plate is provided with a series of grooves 2 and intervening ribs or lateral projections 3 standing approximately perpendicular to the main plane or body 4 of the block orplate. Preferably the heat-receiving sur faces 5 of these grooves and ribs are flared slightly from each other into V shape as .shown. -The resistance conductor is first bent or otherwise shaped in ribbon like form as shown at 6, Fig. 6, and at 7, Fig. 9, the articular arrangement of the successive ben s or turns of the winding being imma terial so long as the general object is secured of having as great a length as possible of wire all lying in one-and the same plane,

i. e. arranged in ribbon-like form. This rlbbon or winding is then creased or reflexed down its'middle as shown in'Figs. 8'

and 9 so as to present opposite .approzdmately parallel upwardly-extending legs or fiat portions 8. If the grooves have their sides flaring, these portions 8 of the reflexed winding will correspondingly flare, or in other words the ribbon-like winding is bent or reflexed to correspond to the shape of the ooves' so as to maintain the leg portions n planes-parallel to the heat r ceivlng and absorbing surfaces of the ribs or walls of the grooves. Having thus formed the wind- I {place as shownin-Fig. 4, and thereupon a:

fused enamel covering 10 or other suitable 'iililg, a layer'9 of enamel or other suitable in ting medium is fused orotherwise applied as a preliminary:l coating-to the iron .or metal constituting t e object to be heated, i. e. to the late 1 inthe illustration of the drawings, t e reflexed ribbon is then put'ininsulating coating is applied so as to embed- ;convey'the electric current for heating the icon or plate 1.

It will be understoed'that any usual -or- 60 preferred means of retaining and embedding ,the resistance wire may be availed of. It

also ,be understood that we are not limited in any way to the particular shapes of ribbon-like arrangements of the windmfgflgr e formofthe grooves, or general shape 0 plate or tool, inasmuch as these are all capable of a wide variety of embodiments within the skill of those versed in the art, without departing from the spirit and scope of our invention. It will also be understood that theplate has transverse end grooves 11, 12 for receiving the wire at the ends, and in eneral the arrangement of the grooves may be varied according to the requirements of the particular tool or device or the preference of the particular constructor, The form shown in Fig. 1 is preferred because of its simplicity and the facility with which the wires may be placed-and embedded.

From the above description it will readily be understood that when the current is turned on, the resistance wire throughout its greatly increased extent conveys from all points thereof uniformly to the adjacent re ceiving surfaces of the ribs 3 the same amount of heat, and inasmuch as the wlre is in ribbon-like formation and stands substantially perpendicular to the general extent or plane of the plate 1 there 1s a greatly increased -length of wire over that which would be possible if the wire were laid in the usual horizontal: windin on the usual horizontal surface or top ,0 the plate or metal constituting the object to be heated. In

other words, our invention provides a large surface parallel to the face of the conductor, insuringthe uniform and rapid absorption of heat at all points, said large surface being much greater in area than the plane or horizontal area of the plate or object to be heated. By this means the exposure of the' generating surfaces of the ribbon-like winding is .radically increased and the uniform absorption of heat therefrom is much greater than could occurby equivalent resistance applied to the flat surface of the heater in the ordinary manner.

Having described ourv invention, what we claim as new and desire to secure by Letters Patent'is'r I 1. In an electric heater, a heat-absorbing body provided with 'aseries of grooves, and

ribbon-like current conductor secured in sald grooves, said ribbon-like conductor being creased "longitudinally and havin its re-' ios flexed sides held substantially para el to the walls of said grooves.v I

2. In an electric he ter, a heat-absorbin body provided with a series-of grooves, an

ribbon-like current conductor secured in' said grooves, said ribbon-like conductorbeing" creased longitudinally and having its reflexed sides-held substantially parallel to thewalls of said grooves, said ribbon-like con-"- ductor containing in I its length a-series of widthwise turns,"providing a correspondlength of the ribbon-like conductor.

3. In an electrlc heater, a-.heat-'abs'orb in body provided with a series of grooves, an

inglydongc'r path for the current than the a conductor, V-shaped in cross section, permanently secured in said grooves with vitreous enamel, the sides of the conductor being embedded in the enamel a proximately parallel to the adjacent walls 0? the grooves.

In testimony whereof, we have signed our names to this specification, in the presence 20 of two subscribing witnesses.

JAS. I. AYER. HORACE B. GALE. Witnesses:

ELIZABETH M. \CIONLIN, DORA A. Pnoc'ron.

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