US1991801A - Rail heating device - Google Patents

Description

Feb. 19, 1935. w H GREENHELD 1,991,801

RAIL HEATING DEVICE Filed Oct. 7, 1930 2 Sheets-Sheet l fu enior WILLIAM H.GREENFIELD Feb. 19,, 1935- w. H. GREENFIELD RAIL HEATING DEVICE Filed Oct. 7. 1930 2 Sheets-Sheet 2 WILLIAM H.GREENFIELD Patented Feb. 19, 1935 UNITED STATES PATENT OFFICE 1 1 Claim.

, This invention relates to rail heating devices and more particularly to electric heaters which are operative to prevent the formation or accumulation of sleet, snow and ice around rail switches and derail points and on conductor rails employed on electrified railroads to deliver power to cars or trains. Primarily the invention consists of heat radiating units positioned at said switch or derail points or at intervals spaced along said conductor rails for supplying heat to the track, these units being electrically operated from local or distant stations as may be desired.

It is among the principal objects of the present invention to provide means for applying heat to predetermined zones of a railway track by direct radiation from a high resistance heating element, this element being in the form of an electric resistor which is adapted to raise the temperature of the rail in the zone in which the element is located to a degree sufficiently high to prevent the formation of sleet, snow or ice in said zone. 1

A further object of the invention is to provide a housing or casing for the resistance element which is so designed as to effectively concentrate the heat in the desired zone whereby the loss in heat transmission from said element to the rail is reduced to a veritable minimum. 1

Still another object of the invention is the pro visionof a casing which is operative not only to resist the radiation of heat outwardly from the rail but which is also designed to support the resistor element against injury due to the vibration and shocks to which it is ordinarily subjected while in use.

A still further object of the invention is the provision of means formed integrally in the re-.

sistor housing for commonly encasing the end terminals of the resistors and the corresponding encasing means being so designed as to greatly facilitate the quick-detachable connection of said conductors with the heating unit.

Still another and important object of the invention is the provision of spring-pressed means for quick-detachably securing the heating unit in operative'position against the rail, said securing means being of such character as to entirely eliminate the necessity for screw or bolt holes in the rail.

Other objects of the invention, such as those relating generally to simplicity in design, economies of manufacture and efficiency and durability in use and specifically todetails of construction will appear more fully hereinafter.

terminals of the conductors leading thereto, these The invention consists substantially in the combination, construction, location and relative arrangement of parts, all as will be described more fully hereinafter, as'shown in the accompanying drawings and as finally pointed out in the ap- -5 pended claim. In the accompanying drawings wherein have been illustrated preferred embodiments of the invention:-

Figure 1 is an elevational view of a rail equipped with a heating unit constructed in accordance with and embodying the principles of the present invention; 1

Figure 2 is a cross sectional view taken on the line 22 of Figure 1; v

Figure 3 is a vertical cross sectional view of the heater unit per se taken on the line 33 of Figure 1;

Figure 4 is a partial transverse cross sectiona view taken on the line 44 of Figure 3;

Figure 5 is a perspective view showing the interior of the unit;

Figure 6 is an exterior perspective view of the unit;

Figure 7 is a perspective view of the conductor plug retaining plate;

Figure 8 is a longitudinal sectional view of one form of resistance element;

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

Figure 10 is a longitudinal sectional view of a modified form of resistance element;

1 Figure 11 is a cross sectional View taken on line 11-11 of Figure 10;

Figures 12 and 14 are plan views respectively of different forms of spring clamps for retaining the heater unit in position; and

Figures 13 and 15 are sectional views taken respectively on line 13--13 of Figure 12 and line 1515 of Figure 14.

Referring now to the drawings and more particularly to Figures 1 to 6 thereof, it will be observed that the rail heating unit, designated generally by the reference numeral 10, is adapted to be mounted in position within the angle formed between the base flange and web of a main rail R. It will be understood that this rail 11 may be a portion of an ordinary track switch or frog or a portion of a conductor rail for supplying electric power to electrically driven cars or trains. It will further be understood that the rail heating units 10 are designed to be located at spaced intervals along the track, particularly at points where the formation or the accumulation of ice, sleet or snow would entail more or less serious consequences.

The heating unit 10 essentially comprises an electrical resistance element 11 which is supported upon the inner surface of a main casing or housing 12. As appears quite clearly in Figures 1 and 2 this housing 12, which is preferably in the form of a sheet metal stamping, is provided with an inclined wall or plate 13 the upper and lower longitudinally extending edges of which are flanged, as at 14 and 15. The side edges of the housing plate 13 are respectively inturned to provide a pair of substantially parallel, triangularly shaped side walls 16. These triangular side walls 16 are so shaped that when the bottom edges 1'? thereof rest upon the upper surface of the base flange of the rail the vertical edges 18 thereof will abut the web of the rail. The main back plate 13 of the sheet metal housing lies in a plane substantially subtending the free edges of the triangular side walls thereof, as most clearly appears in Figure 2. When the housing is applied to the rail an enclosed space or chamber is formed therebetween, this space being bounded at its outer side by the inclined back plate 13, at its sides by the triangular side walls 16, at its bottom by the base flange of the rail and at its inner side by the web of the rail. The heating element 11 is supported upon the inclined back plate in the manner to be described more fully hereinafter and in spaced relation with respect to the enclosed portions of the rail.

In order to most effectively concentrate the heat and to direct it against the rail with a minimum loss in heat transmission the main back plate 13 of the housing or casing is provided with a lining 19 of suitable heat resisting material. As appears most clearly in Figures 2, 3 and 5 this heat insulating lining 19 is maintained in position by means of a pair of angle members 20 riveted or otherwise secured to the side walls 16 of the casing.

Integrally formed in the inclined plate 13 of the housing or casing at longitudinally spaced points thereof are a pair of outwardly pressed portions 20 providing a pair of sockets the axes of which lie in a plane outwardly offset with relation to but paralleling that of the inclined plate. The upper end of these socketed portions 20 are curved as at 21 (see Figure 3) to merge into the plane of the inclined back plate 13 while the lower ends of the said socketed portions 20 are open for reception of the conductor plugs 22. These plugs 22, which are electrically connected to the ends of conductors 23 for supplying current to the resistance element, are preferably in the form of female elements adapted for cooperation with the male terminal elements 24 of the heating unit, these male terminal elements being respectively enclosed within the upper ends of the socketed portions 20 in the manner to be now described.

As appears most clearly in Figure 3 the terminal elements 24 of the heating unit comprise an insulating body 25 which is adapted to be nested within the upper closed end of the socketed portions 20. These insulating bodies 25 are each provided with a rearwardly extending portion 26 projecting through a suitable aperture 27 formed in the heat insulating lining 19. The insulating bodies 25, which are of substantially angular form in vertical section, are respectively designed to insulatingly enclose the central body portions of the electrical conducting members 28. These latter members are each of substantially right angle form, one branch of which extends axially of the socket portion 20 and terminates in a freely projecting pin 29 arranged for electrical engagement within the female terminal member of the conductor plug 22. The other branch of the conductor member 28 extends axially through the rearwardly extending portion 26 of the insulating body 25 and terminates in a freely extending threaded portion 30.

Angle members 31 of the character shown most clearly in Figure 5 are secured to the threaded ends of the terminal members 28 by means of nuts 32, these angle members being so respectively secured in position that the branches 33 thereof are arranged in substantial parallelism and between which is supported the resistance element 11.

This resistance element 11 essentially comprises a tubular member 34 of refractory material about the external surface of which the resistance wire 35 is spirally wound. Arranged at either end of the tubular member 34 is a spool 36 of non-conducting material and of a diameter greater than that of the tubular member 34. The latter member and the end spools 36 are maintained in assembled relation by means of a metal tube 37 the opposite ends of which are respectively secured, as at 38, to the spools 36. This ecurement is preferably accomplished by spinning or otherwise forcing the ends of the metal tube 37 into annular grooves respectively formed in the spools 36. The space formed between the inner refractory tube 34 and the outer metal tube 37 is preferably filled with insulating material 39.

In order to effect the necessary electrical connection between the ends of the resistance wire 35 and the angle brackets 31, which latter are in electrical engagement with the male terminal elements 28 of the heater unit and at the same time afford a substantial mechanical joint between the insulating tube 34 and its supporting end spools 36, the arrangements shown more particularly in Figures 8 and 10 are employed. In the form shown in Figure 8, end studs 40 are employed, these studs being each characterized by the provision of a threaded shank 41 and an enlarged head 42 of substantially rectangular cross section, the spool 36 being provided in its inner surface with a rectangularly shaped socket for partially accommodating said rectangular head 42. The adjoining end of the tubular member 34 is diametrically slotted, as at 43, for nonrotatably receiving that portion of the stud head 42 which projects interiorly of the end spool. With the head 42 of the stud thus commonly accommodated within the socket portion of the end spool and the slotted portion of the tubular member 34, relative rotation between said spool and member is effectually precluded. The head 42 of the stud is suitably apertured, as at 44, to permit the projection therethrough of one end of the resistance wire 35, said wire being suitably brazed or otherwise permanently secured to said head to effect a positive electrical connection therebetween. The threaded shanks 41 of the studs extend through axial bores respectively provided in the end spools 36, the exteriorly projecting portions of these threaded shanks 41 being adapted for projection through suitable apertures formed in the lower ends of the portions 33 of the supporting brackets 31. Nuts 45, threadedly engageable with the shanks 41, serve to maintain the resistance unit in the position shown most clearly in Figure 5.

Figures 10 and 11 show an alternative arrangement for preventing relative rotation between the tubular member 34 and the end spools 36.

In this modified construction studs 46 are em ployed which differ from the studs 40 of Figure 8 in that they are each provided with an axial extension 47 adapted for projection into the bore of the tubular member 34. This axial extension 47 is anchored within the end of the tube 34 by means of a tubular pin 48 which is projected diametrically through the tube and extension. The enlarged rectangularly shaped head 49 of the stud is non-rotatably positioned within the correspondingly shaped socket 50 formed in the end spool such that the inner surfaces of said head and spool are flush with one another. The ends of the resistance wire are respectively threaded through the tubular pins 48 and are secured thereto as by brazing, soldering or otherwise whereby a permanent electrical connection is effected between each end of the wire and one of the studs 46. In all other respects the resistance unit of the form shown in Figure 10 is similar to that shown in Figure 8, both forms being removably supported between the bracket members 31 in the manner appearing most clearly in Figure 5.

It will thus be seen that the opposite ends of the resistance Wire are respectively connected to the male terminal elements 28 of the heating unit through the intervention of the end studs and the supporting brackets. Due to the angular form of the terminal elements 28 and the fact that the extremities thereof project axially of the socketed portions 20 of the heater casing, the ease with which the conductors may be connected to the unit is greatly facilitated. As was described hereinbefore, these conductors are each provided with a plug 22 adapted to be snugly received within the socketed portions 20.. These plugs 22 are each provided adjacent the outer ends thereof with an annular groove 51 which is adapted to receive a spring-pressed finger 52 for preventing accidental or unintentional displacement of the plug from within its socket.

The spring-pressed fingers 52 are preferably formed as integral parts of a plate member 53 interposed between the back plate 13 of the heater unit and the insulating-lining plate 19. As ap pears most clearly in Figures 2, 3 and '7 the struckout fingers 52 are arcuately shaped in transverse cross-section and are so disposed that they respectively constitute the bottom walls of the inclined plug sockets 20. The free extremities of the spring-pressed fingers 52 are each beaded, as at 54, to provide a detent or the like for engagement with the groove 51 of the conductor plug when the latter is inserted into position.

It will be understood, of course, that any suitable means may be provided to maintain the heater unit in the operative position shown in Figures 1 and 2. It has been found preferable, however, to employ a spring clamp 55 having a flat body or plate 56 which is adapted to underlie the base flange of the rail and a spring-pressed pivoted member '7 adapted to overlie the inclined back plate 13 of the heater. The plate 56 of this clamp is preferably provided at opposite ends thereof with upstanding flanges 58 and 59 for respectively engaging opposite edges of the rail base flange. The central portion of the flange 59 is rolled, as at 60, to provide a bearing for a horizontally extending sleeve 61 within the opposite ends of which are inserted the free lower ends of the bail member 57, this latter being preferably in the form of a rod bent into the shape shown most clearly in Figure l. Embracing the oppositely projecting portions of the sleeve 61 is a coil spring 62 which is operative to constantly urge the upper portion of the bail member 57 toward and against the plate 13 of the heater unit, thereby definitely forcing the latter into the angle formed between the base and web of the rail.

The use of a spring clamp of the character just described eliminates the necessity of employing screws or bolts for securing the heater to the rail at the same time that it greatly facilitates the ease with which the unit may be secured to and removed from the rail. Should it be desired to remove the unit from the rail for purposes of inspection, replacement or repair it is merely necessary to pull the plugs from their sockets and then swing the bail member 57 outwardly about the sleeve 61 as an axis whereupon the unit may be bodily removed from the rail, no tools of any sort being required in this operation.

In certain instances the base flange of the rail may vary from the standard and accordingly it may be desirable to employ a spring clamp having an adjustable base plate as shown in Figures 12 to 15. In the form of clamp shown in Figures 12 and 13 the base plate is formed of two members 63 and 64, the member 64 being provided with a spring-pressed bail member 65 similar in design and function to the hereinbefore described member 5'7. The inner portions of the members 63 and 64 are adapted to be arranged in the superposed relation shown, the side edges of these portions being respectively kerfed to provide a plurality of alternately arranged tongues 66 and slots 67. These tongues are all inclined with respect to the planes of their respective body members and are relatively so arranged that the tongues of member 63 interlock with the tongues of member 64 when said members are assembled in the relation shown. Obviously, the distance between the outer ends of the members 63 and 64 may be varied within wide limits to accommodate base flanges of different widths merely by changing the interlocking relation between the kerfed portions of the members.

In Figures 14 and 15 an alternative arrangement is shown wherein the member 68 of the spring clamp is provided in opposite sides thereof with a plurality of longitudinally spaced slots 69, the member 70 being provided in turn with a pair of laterally spaced downwardly presenting lugs '71 adapted to be projected through any desired set of slots 69. In this alternative arrangement, it is preferable, when the members 68 and-'70 are assembled in properly adjusted relation, to bend the lugs 71 upwardly against the bottom surface of the slotted member whereby to more positively lock the members 68 and '70 together.

Returning again to the resistance unit per se, it will be observed that the end studs thereof are longitudinally bored, as at 72, to provide a continuous passage extending longitudinally through the resistance unit. This passage permits of a circulation of heated air outwardly from the center of said unit to supplement the heat radiated from the external surface thereof.

The resistance unit and the clamp form the subject matters of applications Serial Numbers 626,573 and 626,574, respectively.

It will be understood of course that the invention is susceptible of various changes and modifications other than those hereinbefore pointed out, all without departing from the general principles or real spirit of the invention, and it is accordingly intended to claim the same broadly,

as well as specifically, as indicated by the appended claim.

What is claimed as new and useful is:-- In an electric heater, in combination, a protec- 5 tive casing for an electric heating unit comprising a. main back wall having an outwardly pressed portion constituting a socket for a. conductor plug, a heat insulating lining for said back wall, and a plate interposed between said lining and said wall and having means projecting interiorly of said outwardly pressed portion for frictionally engaging a conductor plug inserted Within said socket.

WILLIAM H. GREENFLELD.

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