US2458225A - Electric heating unit - Google Patents

Description

Jan. 4, 1949.

D. M. TRILLING ET AL ELECTRIC HEATING UNIT 5 Sheets-Sheet l Filed Feb. 8, 1946 INVENTOR. DAVID m. TRiLLING GEORGE H RKC 1949- D. M. TRILLING ET AL 322,458,225

' ELECTRIC HEATING UNIT Filed Feb. -s, 1946 a Sheets-Sheet 2 53 52 INVENTOR.

Dawn M. Tmmhme BY GEQRQE H- ElcH 'Jan. 4, 1949. D. M. TRILLING ETAL. I 2,458,225

ELECTRIC HEATING UNIT Filed Feb. 8, 1946 3 Sheets-Sheet 3 INVENTOR. V M. TE'HJJHG BY GEORGE H m Patented Jan. 4, 1949 ELECTRIC HEATING UNIT David M: Trilling, Merion, and George H; Rich, Philadelphia, Pa., assignors to Trillingand Montague, Philadelphia, Pa.,

apartnership 1 composed of David; M; Trilling and Harry Montague Application February 8, 1946, Serial No. 646,310

4'Claims. 1;.

The present invention relates generally to electric space heaters and more; particularly to such heaters: of'the cabinet typewhich are internally provided with several flue-forming elements'so arranged in relation toeach other and to surrounding parts of the heating cabinet that all said parts mutually reinforce each other to providea rigid and rugged construction of cabinet heater at the same time that they provide the cabinet withflues which serve not only to directthe heated air upwardly of the heater cabinet, but also to maintain-theexternal side surfacesthereof relatively cool.

Among the-principal objects of the-present invention is to provide a rugged electric resistor heating unit of simple construction, which can be manufactured with great facility and in which the-resistance wirecan be readily replaced when desired or necessary.

A further object of the invention is-toprovide aresistor-unit which can be mounted in the space heater cabinet with greatfacility and which may be: readily removed and replaced with the mini mum interference with the cabinet construction.

Another object of' the present invention is to providean electrical resistance unit, the wattage otwhichmay'be varied, as desired, without necessitating any corresponding changes in the design or dimensions of the supporting core for the resistance-wireof the unit'.

Sti'll:another object. of the inven-tionis to provide for the ready installation of the'resistor. heating: unit in the-cabinet.

Other objects and advantages of the present invention willappear more fully hereinafter, it being'understood that the present. invention consists substantially-in the. combination, construction, location and: relative arrangement of parts, all as. described'in more or less detail hereinafter, as: shown in the accompanying drawings, and as finally pointed. outin the appended. claims.

In. the said accompanying drawings, which. are illustrative of: certain preferred; constructions embodying the: principles of; the present invention:-

Figure L is: a horizontal sectional view of the cabinet, heater embodying the present invention;

Figure, 2 is a. sectional view taken. on. line 22 OfzFlBllfB 1;.

Figure 3 is an enlarged fragmentary section taken on line,3-3 of Figure 1;

Figures 4 and 5 are. top and bottom perspective; views of: the supporting.- cross bar employed in thepresent invention;

6- is; side v ew or an electrical. esi

anceheating unit" embodying the present invention? Figure 7- is-a sectional view on line 7-! of Figure 6;

Figure 8 is a fragmentary detail of a modified construction of the straight wire resistance unit of thetypeshown in Figure 6;

Figure 9 is a sectional view on line 9-9 of Figure 8;

Figure 10 is a side elevational view of a modified form of resistance unit employing a helically coiled resistance wire wound upon its supportingcore;

Figure 11 is a fragmentary detail of a modified construction of the coiled wire resistance unit of the type shown in Figure 10;

Figure 12 is an elevational view of the self locking anchoring stud or button employed for securing the resistance wire to the core;

Figure 13 is a sectional View on line Iii-l3 of Figure 10;

Figure 14 is a sectional View on line i i-l4 of'Figure 11;

Figure 15' is a sectional view on line i5l5 of Fi'gure 14'; and

Figure 16 is an end view of a unit of the type shown in Figure 10 with the coil resistor wire stretched to decrease the effective length of the wire and so provide a higher wattage unit.

The resistor unit of the present invention comprises asv its essential elements a core 33 and a resistance wire 3i nominductively wound thereon. The core may be of any suitable refractory insulating material and in the preferred form the core is an elongated hollow cylinder of ceramic material. The core is preferably hollow from end to end so as to provide for the free passage of air therethrough.

One feature of the present invention aims to provide a core upon which a predetermined length of wire 3'! may be wound with facility. For this purpose a pair of parallel helical grooves 32 and 33- are preformed upon the exterior ofv the core, the grooves beginning and ending somewhat short of the ends of the core to provide for the reception of; the cup-shaped supporting elements to be described later. As will be seen from the draw ings, the grooves extend substantiall from end to end of. the core and cover substantially all of the-exterior face of the core.

An opening 34 extends through the Wall of the cylinder adjacent one end of the parallel pair of grooves and may be said to bridgethe grooves, the location of the opening 34 being such that it serves, as. a socket. for an anchoring stud employed to anchor in position the midpoint of the single continuous resistance wire carried by the core.

At the opposite end of each of the parallel grooves, the ceramic core is provided with an opening 35 extending through the wall of the core. In the form shown in Figures 6 and 7, the core to is provided with a second pair of openings 36 respectively in alinement with the openings 35. Thus, each pair of the alined passages 35 and 35, provide for the passage therethrough of the terminal ends of the wire 3i .so that they respectively extend across and through the lower end of the core 35 for anchoring thereto. The terminal ends of the wire may be twisted together as shown at 3'! to form terminal eyes El Figure 12 shows the self-locking anchoring stud All which will be seen to have a shank 4|, with a constricted portion forming an annular groove 42, and an enlarged base 53. The stud may be made of metal or any suitable material and the diameter of its shank (ll approximates the diameter of the openings 34 and 35 in the wall of the core.

In use, the anchor stud 40 is inserted through the passage 34 from the interior of the core as shown in Figure 7, the shank 4| of the stud being of such length that the groove 42 thereof lies just outside the exterior surface of the core 30. In winding the resistance wire 3| on the core, a predetermined length of wire is folded at its midpoint and the midpoint of the wire is placed in and around the stud groove 42 and the two branches of the wire are then laid in the two parallel helical grooves 3233 and wound around the core. The stud 49 thus serves to anchor firmly the midpoint of the wire to the core, the wire serving in turn to lock the anchor stud it in its anchoring position. After the wire has been. wound by laying the two halves in the parallel grooves, the terminal ends of the wire are laced through the passages 35 and 36 thereby anchoring the terminal ends thereof in position. The heater unit is thus ready to be installed in the cabinet. The cabinet and supporting device for the heating unit will be described in a later portion of the specification, after further modiiioations of the resistance unit are described.

One such modification is shown in Figures 8 and 9 and relates only to the manner and means of anchoring the free or terminal ends of the wire to the core. In this form of construction, a pair." of openings 45 are respectively provided at the terminal ends of the spiral grooves 32 and 33, the openings being counterbored as shown at 5. The self locking anchoring studs ll! are inserted into the openings 45-t5 and the ends of the wire 3i are twisted around the stud grooves, thereby securely anchoring in position the ter minal ends of the wire. The free ends of the wire should, preferably, pass under the wire as the encirclement of the stud All! is completed as shown in Figures 8 and 9, thus insuring that the wire locks the stud in position.

Figures 10 to 16, inclusive, show other modifled resistance units which, instead of the straight resistor wire 3!, employ a helically coiled wire resistor i on the core. The core '55, like core 33, is externally formed with a pair of parallel helical grooves 52-53 which correspond to grooves 32-433 of Figure 6, except that the grooves 52 and 53 are deeper and wider so as to accommodate the helically coiled wire 55. The employment of the coiled wire permits for variation of the wattage of the unit asthe same is prepared or assembled by the simple expedient of stretching or compressing the coil to vary its effective total length. Figure 10 shows a relatively compressed coil 5!, while Figure 16 shows a relatively stretched coil. With the wire of the same gauge in both forms, the stretched coil in Figure 16 provides a unit of higher wattage than the compressed coil unit of Figure 10, assuming, of course, that the cores are formed with the helical grooves of the same lengths.

The units shown in Figures 10, 13 and 16, like the units shown in Figures 6 to 9, each employ the anchoring stud 4B for anchoring the midpoint of the resistor wire to the upper end of the core. At the lower end, the free ends of the wire may be anchored by studs 45 as described previously in connection with Figures 8 and 9. In Figures 10, 13 and 16, the studs 55 at the terminal ends of the wire are preferably spaced axially of the core, because the larger width of the grooves 52, 53 permits such spacing.

Figures 11, 14 and 15 show end anchors applied to the coil, which are like the anchor means in Figures 6 and '7. In this form, one side of the core at has a pair of axially spaced radial openings 54 and the opposite side of the core has another pair of openings 55, preferably circumferentially spaced. Each terminal end 56 of the wire passes through a pair of openings 5t and 55 and is then twisted, as shown at 55, to provide a terminal eye 55 The several forms of the heating unit each comprising the preformed and pregrooved insulating cylindrical hollow core with their pr'eformed anchoring passages thus greatly facilitate the production of these units. The positions of the anchoring passages predetermine the length of wire to be wound on the core and the self-locking anchoring stud, whether employed only at the top to anchor the midpoint of the wire, or employed at the terminal ends as well, permit anchoring the wire on the core with great facility and predetermine the wattage of each unit.

Another phase of the present invention resides in the means for the ready installation of each unit in the cabinet type of space heater shown in Figures 1 and 2 and described later. Two views of the carrier or support are shown in Figures 4 and 5. The carrier or support is a metal stamping 60 having a central circular hole 5! which approximately corresponds in diameter to the inner diameter of the hollow core 30 or 55, thus providing an unobstructive passage interiorly of the core. The substantially annular portion 52, which surrounds the opening 6!, approximates in dimensions the wall thickness of the cores 3!? or 5B. The flanges 63 with the annulus 52 form a cup-like receptacle for snugly receiving an end of the cores 39 or 5B. The arms 64 have angular portions 65 and the flanges 63 extend the length of the arms 84 to lend rigidity to the arms.

The inner faces of the side walls of the cabinet are provided with channel-shaped cleats 55 welded to the walls to form sockets to receive the portions 65 of the supporting elements 66. In lieu of welding these cleats 66 to the cabinet walls, they may be otherwise secured thereto or they may be formed as integral parts of said walls, as by striking the same therefrom. The terminal portions 65 0f the supports may be crimped over the cleats as shown in dotted lines in Figure 3. Of course, instead of securing the terminal ends of the supports 60 to the cabinet walls by way of cleats as shown, any other suitable means may be employed for this purpose.

As shown in Figures 1 and 2 each heating unit is provided with a, support 60 at its top and bottom. The heater units are disposed in a vertical position with the midpoint of the non-inductive winding of resistor wire at the top and the terminal ends of the wire at the bottom. The midpoint of the resistor wire is thus at the hot end of the unit and the terminal ends are at the cool end of the unit. As shown in Figures 1 and 2, one pair of terminal ends from the two heating units are joined at the terminal and the other pair of terminal ends of the windings from the tWo units are connected to the terminals H, the two units being thus series connected.

The cabinet employed for housing and supporting the heating units is illustrated in Figures 1, 2 and 3 only to illustrate the preferred type of cabinet and may be briefly described as comprising an external housing In and an internal flueforming unit l l, the heating units being indicated by the reference characters 20, two being shown as mounted within and on the internal unit ll.

What is claimed as new and useful is:

1. An electric resistor unit comprising a hollow cylindrical core having a pair of parallel helical grooves on its exterior, the cylindrical wall of said core having a transverse passage extending therethrough in common registry with said pair of grooves adjacent one end thereof, an anchoring element having an enlarged head disposed internally of said core and a shank extending outwardly through said passage, said shank having an intermediate constriction therein immediately adjoining the external surface of said core, and a coiled resistance wire doubled upon itself to provide a pair of parallel branches, said branches being respectively disposed within said pair of grooves with the portion of said coiled wire intermediate the coiled branches thereof looped about the constricted portion of said anchoring element, whereby said looped portion is anchored to said element simultaneously as it looks said element to the core.

2. An electric resistor unit comprising a hollow cylindrical core having a pair of parallel helical grooves on its exterior, the cylindrical wall of said core having a transverse passage extending therethrough in common registry with said pair of grooves at one end thereof and a pair of spaced transverse passages extending therethrough in respective registry with each of said pair of grooves adjacent the opposite end thereof, a coiled resistance wire doubled upon itself and wound about said core with the parallel branches thereof respectively disposed in said pair of helical grooves, and a plurality of anchoring elements respectively disposed in said transverse passages, each of said elements including an enlarged end disposed internally of the core and a shank projecting outwardly of each passage, said shank having a constriction immediately adjacent the external surface of the core for receiving a looped portion of the resistance wire whereby said looped portion is anchored to the element and the latter is locked to the core.

3. In an electric resistor unit comprising a hollow cylindrical insulating core and a coiled resistor wire Wound spirally thereon, the core having transverse passages in its wall to receive anchoring means for said wire, and anchoring means for said wire in the form of studs each having a shank extending through and projecting from the passage and an enlarged head engaging the inner face of the core wall, the projecting portion of the shank having an annular constriction immediately adjacent the outer face of the core wall for receiving a looped portion of the wire, the looped portion of the wire serving as a locking ring to anchor the stud to the core.

4. An electrical resistor unit comprising a hollow cylindrical core externally formed with a pair of parallel helical grooves, said core having an opening in the wall thereof adjacent one end of said pair of grooves, a stud extending through said opening, the projecting end of which is provided with an annular groove disposed immediately adjacent the external surface of said core, a non-inductively wound coiled resistor wire having a pair of parallel branches respectively disposed in the external helical grooves of said core, the portion of said wire intermediate the branches thereof being disposed in and looped about the annular groove of said stud whereby the latter anchors said looped portion of the wire to the core at the same time and said looped wire portion secures the stud in position upon said core, and means for securing the opposite terminal ends of said wire to said core at points located adjacent the opposite end of said grooves and in spaced relation with respect to each other, said coiled resistor wire branches being each variable in length between said stud and its end securing means to vary the voltage of said unit.

DAVID M. 'I'RILLING.

GEORGE H. RICH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 15,047 Boardman Feb. 22, 1921 1,234,973 Trood July 3 1917 1,401,500 Scott Dec. 27, 1921 2,391,065 McKinley Dec. 18, 1945 2,405,072 Trilling et al July 30, 1946 FOREIGN PATENTS Number Country Date 687,629 Germany Feb. 2, 1940

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