US2167922A - Rail treatment furnace and control means therefor - Google Patents

Description

, 1939. A. G. WITTING ET AL RAIL TREATMENT FURNACE AND CONTROL MEANS THEREFOR Filed May 20, 1938 3 Sheets-Sheet l wk. RM 0 HM; M nn hm HHI INVENTORS ALB/N arr/Na. L/bI-I Fla f0 1, 1939- A. G. WITTING ET AL 2,167,922

RAIL TREATMENT FURNACE AND CONTROL MEANS THEREFOfi F iled May 20, 1958 3 Sheets-Sheet 2 srzlsyaus .6

INVENTORS 14L auv G. Vl n'r/Nc;

BY Jaw/v fkzp H54 0455:.

ATTORNEY Aug. 1, 1939-. A. G. WITTING ET AL 2,157,922

RAIL TREATMENT FURNACE AND CONTROL MEANS THEREFOR Filed May 20, 1958 s Sheefs-Sheet s INVENTOR3 ALB/N G: mrrl/vc'.

B JH/VIEEDZEZWQLEE E g ATTORNEY atented Aug. 1, 1939 UNITED STATES PAT'E OFFICE adopter Ran. TREATMENT rnRNAcE MEANS THEREFOR l UONTROL Albin G. Witting and .lo Fred Headlee, Gary, ind.

Application May 220, 1938, Serial No. 209,128

12 Claims.

adapting the furnace to the practice of the socalled Brunner process described and claimed in Brunner Patents Nos. 1,896,572 and Re. 19,884 issued Feb. 7, i933 and Mar. 10, 1936, respectively.

One of the objects ofthe present invention is to provide a furnace adapted to successively heat lo treat a plurality of groups of rails, rods, bars and the like elongated steel articles, in accordance with the process described and claimed in the above identified Brunner patents. Another ob- ."iect of this invention is to provide a control ltl means for the said furnace adapted to render the operation of said furnace substantially automatic. Still another object of this invention is to provide an. economically practical rail treatment plant including a furnace, associated apparatus to depp liver rails to the furnace, to feed rails through the furnace and to carry the rails away from the furnace and an electrical control system for the various operating units of the furnace and said associated means adapted to render the operation and co-operation of the assembly substantially automatic. Another object of the present invention is to provide means to effectively practice the method invention of the said Brunner patent. Uther objects and advantages will be apparent as the invention is more fully disclosed.

In accordance with these objects we have devised the heat treatment apparatus of which the following description, together with the accompanying drawings, is a full and complete disclosure. Before further describing the present invention, reference should be made to the accompanying drawings wherein Fig. l. is a plan view showing the complete assembly of apparatus elements comprising the present invention; Fig. 2 is an enlarged plan view of the furnace, feed and delivery tables, together with the main control elements therefor; Fig. 3 is an enlarged vertical sectional view in section to amplify. the showing of Fig. 2; Fig. 4 is an enid larged plan view of the furnace, feed and delivery tables. with the electrical control means therefor schematically illustrated in one operative position; and Fig. 5 is a second plan view similar to Fig. 4 showing the electrical control means scheso matically in a second operative position.

" The Brunner process described and claimed in the above identified patents contemplates subiecting the steel article, for example a railroad rail, to a grain refining heat treatment after the my rail has been coolecl'from the rolling temperature (lDl. 263-6) down to a temperature below the so-called transformation temperature but above a temperature as low as 300 C. This grain refining heat treatment substantially comprises a heat treatment at a temperature approximating but above the up- 5 per critical temperature. After the rail has been subjected to this so-called grain refining heat I greater degree of hardness to this portion of the head section, as described in Brunner Patent Re. No. 19,884.

The furnace and associated apparatus, niechanit ical and electrical, of the present invention is designed specifically to provide means to practice this Brunner method of treating rails, but it is apparent that the same apparatus is as equally adapted to the heat treatment of other elongated to steel articles, such as rods, bars and the like, and the furnace structure per se and the heating means provided therefor is also adapted for the practice of other heat treatment processes. 'll'herefore, the following description of the fur 25 pace in its specific adaptation to the heat treatment of rails in accordance with the Brunner process is to be understood as being a description of one specific embodiment of the present invention, and the claims herewith appended are not 3GP to be construed as being limited in scope to the described and specific embodiment.

Referring now to Fig. l, furnace F is an elongated roller bottom type furnace provided with door closed inlet and outlet openings 4 and t in 35 opposite end walls. The length of the furnace F is adapted to enclose a plurality of rails in end spaced relation, for example, eight rails of the longest length now commonly produced. The width of the furnace F is adapted to enclose a 40 plurality, for example eight, rails in side spaced relation. The roller bottom of furnace Fis comprised of a plurality of parallel spaced rolls l, each comprised of high temperature oxidation resistant material, and located between opposite side walls of the furnace in a position to advance the rails lengthwise longitudinally of the furnace from the inlet opening 4 to the outlet opening. 5. The shaft ends of rolls I extend through the side walls ofthe furnace and engage drive shaft 2 m driven by motor means 3.

The interior of furnace F is heated by means of fluid fuel burners 6 located in alternate spaced relation alongeach side wall, each burner '5 being supplied with air and fluid fuel from mains l and 8, the mixture to eachburner i being regulated by means of valve 9. Thermocouple l located interiorly of the furnace F operates through control means II to regulate valve 9 to vary the airfuel mixture so as to maintain a desired thermal condition within determined temperature limits in the section of the furnace under control of thermocouple M. This thermal control means per se being no part of the present invention and being readily understood by one skilled in the art need not be more specifically described.

For the purpose of the present invention, we

- have divided the interior of furnace F into a plurality of heat zones 1 to I and in each zone provide a separate thermocouple l0, each of these thermocouples controlling the operation of the burners 6 located in its particular furnace section so that we may control the thermal condition in each of the furnace sections f to I. In the top of furnace F, we provide fan means 24, preferably one for each section l 'to I to force the hot gases of combustion downwardly to the bottom of the furnace upon and-about the furnace rolls 1 and the rails located thereon.

Rolls l are spaced above the refractory bottom of the furnace a sufllcient distance to provide 'a substantiallyclear passageway lengthwise of the furnace for the flow of the hot gases of combustion towards the opposite furnace ends. Adjacent each opposite end and in the bottom of the furnace we provide the openings l2 and it communicating with separate underground flues I4 and I5 each opening to a common stack It through damper means I! which regulates the total draft on flues l4 and IS. The proportion of this total draft applied to each flue it and I5 is regulated by damper means is and It respectively.

On the furnace side of main stack damper ll of flue it we provide a by-pass conduit 20 opening to a water cooling means 2| provided with a fan means (not shown) adapted to draw gas from flue it through the cooler' Ii and to feed the cooled gases through valve 22 into flue I! when damper means I! and I0 respectively are closed and valve means 22 is open. This particular furnace gas cooling means is described and claimed in our co-pending application Serial No. 209,127 flled May 20, 1938 and need not be further elaborated upon for a proper understanding of the present invention. The object of this particular means is to provide for the more rapid cooling of the furnace interior during periods of shut-down. The interior of furnace F is lined with suitable refractory material, as is customary in the art, to withstand the relatively high heat treating temperatures required in the heat treatment of steel.

With this particular furnace structure hereinabove described we may obtain lengthwise of the furnace a substantially uniform temperature or a graduated range of temperatures from inlet to outlet openings, and we can regulate the thermal condition at the inlet and outlet openings respectively within relatively wide temperature ranges by controlling the thermal input to the various zones of the furnace and by regulating the draft "conditions in flues I4 and II to pull the furnace gases towards inlet and outlet openings preferentially. In the practice of the Brunner process it is desired to reheat the rail after it has cooled below the transformation temperature (about 700 C. for ordinary rail steel) to temperatures approximating but above the upper critical temperature, before the rail in cooling below the said transformation temperature has cooled as low as 300 C. The preferred mode of heating the interior of the furnace F is that adapted to heat the rail as rapidly as possible to the maximum heat treatment temperature desired in the practice of the Brunner process and to provide a relatively prolonged time interval for soaking at this temperature so that a substantially uniform temperature throughout is attained Just before the rail is discharged from the furnace. It is essential, therefore, to maintain the discharge section I of the furnace at or about the maximum temperature of heat treatment for the rail and the several sections just preceding the discharge section I also should be at a temperature closely approximating this maximum temperature. For rapid heating of the rail to this desired maximum temperature the temperature of the inlet section I should be maintained as closely approximate the maximum desired temperature as is obtainable in view of the periodic insertion of relatively cold rails within the furnace. 1

In any rail treatment process it is essential that uniformity of product be obtained and to obtain uniformity of product in the operation of furnace F and in the heat treatment of rails therein it is necessary to standardize or to regulate the temperature of the incoming rails. In the practice of the Brun'ner process we have found'that the maximum temperature of heat treatment should approximate 900 C., and that' it is preferable to limit variations in the incoming rail temperature to within about C. We have found that the most satisfactory results are obtainable where the flrst cooling of the rail to below the transformation temperature is limited to within the range 500 to 600 C. This enabla us to maintain a minimum temperature differential between inlet and outlet ends of furnace F; avoids the detrimental results incident to a too rapid heating of a colder rail to a temperature above the upper thermal critical temperature: and accelerates the rate at which rails may be fed through the furnace in the practice of the Brunner process. Under these conditions, the temperature of inlet section I can be maintained at about 840 C. by proper manipulation of dampers II and II in flues M and ii,

Rails for treatment in the furnace F are delivered by roller table R from the finishing rolls and hot saws (not shown) onto hot bed H whereon they are allowed to cool at the normal rate in freely moving air. until below the transformation temperature but above about 800 C. Therailsduringthecoolingonhotbedfl are progressively moved in the direction of the arrow by any suitable transfer means old in the art towards the discharge end of hot bed H and are then transferred one at a time, onto roller table It along which they are carried in the direction indicated by arrows until the rail end abuts against stop ll located in a position which will bring the opposite end of the rail in desired spaced relation with the rails next adjacent the inlet opening 4' in furnace F. The chain transfer dogs 20-4011 actuated by motor means 21-- 2111 transfers the rail onto hot bed II. From hot bed 11 the rails are moved onto approach roller table T by transfer means "-201: whereon they are grouped in side spaced relation. Table 'I' is provided with a plurality of rolls 2'' driven by a motor 20 which at periodic intervals aswillbehereinafterdescribedoperatestofeed the side spaced group of rails thereon'endwise in the fiu'nace.

into fiunace F through door closed inlet opening 4. Simultaneously with the feeding of this group of rails into the furnace F motor means 3 driving furnace rollers l is actuated to advance a similar distance each of the rail groups then Simultaneously also with the operation of motors 23 and 3. motor .30 actuating rollers 3| on table 'I? is actuated'to receive a batch of rails being discharged from furnace F and to carry the rails away from door closed outlet opening onto table '1'. During the time interval in between the periodic feeding of rails from table T into furnace F the heat treated rails on table '1 may be subject to the end hardening step of the Brunner process by the means indicated (Fig. 2) which means is more particularly described and claimed in copending application Serial No. 227,602, flied Aug. 30, 193B.

Following this cooling step (if applied to the rails) the rails may be transferred from table '1" onto hot bed H for further cooling and thence to roller line R where they may be carried in the direction of the arrow to [a storage bed for straightening or for further finishing heat treatment as desired. Chain lift means actuated by motor 32 may be utilized to remove rails from table 2 onto hot bed H A second chainlift means actuated by motor 33 may be utilized to transfer the rails from hot bed H onto roller line R and motor means 34 may be utilized to actuate the rollers of roller line R These means being common to the art need not be further identified.

To synchronize the forward drive of the furnace rollers and the rollers of tables T and T we provide magnetic clutch means 35 and 36 to engage drive shaft 2 of the furnace to the respective drive shafts driven by motors 29 and 32 and driving the rollers on, these said tables (T and T We also provide a switch means 31 on approach table T which operates when the rear end of the forwardly driven rail clears switch 31 to throw into the field circuit of each driving motor 29, 3 and 30 an electrical resistance 'suflicient to cut down the forward driving speed of the motors 29, 3 and 33. This means per se also is old in the art and need not be specifically described.

Within furnace F adjacent each door 4 and 5, we provide a photo-sensitive means 33 and 39 respectively operated by a beam of light radiation projected through the furnace which operates to energize means to automatically terminate the forward driving of alllof the rollers in furnace F and tables T and T when the rear end of the rail clears the projected llght'beam,

end cooling hoods 42; and the practice of the I end hardening step of the Brunner process substantially as described and claimed in co-pending application Serial No. 227,602 above identifled.

The above identifl'ed apparatus elements of the present invention may be coordinated into an automatically operating assembly by the elecfrom roller line B.

trical system schematically illustrated in Figs. 4 and 5 inclusive. In the'usual rail manufacturing process rails are delivered from the hot saw onto hot bed H in rapid sequence and are transferred from hot bed H to roller line B. for ,de-.

livery to hot bed l-I similarly. An operator located in pulpit P can manually control the selection of the rails passing along roller line RF for delivery to hot bedH by transfer means 26-26:: and a second operator located in pulpit P can manually control the transfer of the rails from hotbed H ontoapproach table T However, the feeding of the rails into, through and out of furnace F ontodelivery table '1 should be regulated with suilicient uniformity as to insure uniformity in the treated product.

We have, therefore, devised the electrical control system illustrated in Figs. 4 and 5 inclusive to effectively control the automatic operation of the furnace so that the rails may be fed at timed intervals into the furnace by approach table T and out of the furnace onto delivery table T2 with a minimum time delay and with minimum heat losses in the interior of the furnace. During the time interval between the feeding of successive batches of rails into the furnace F the furnace rollers must be oscillated back and forth to prevent sagging of the rollers and to prevent local cooling of the rails located thereon. Various safety devices also have to be provided to insure the automatic operation of the various instrumentalities of the present invention in the order desired and at-the time -desiredn.

Briefly stated, the electrical control system of I the present invention is operated at determined time intervals to perform the following functions in the sequence or order given:

At the end of a determined time interval, which is variable within wide limits under the manual control of the operator in pulpit P to provide a sufficient time interval for rails to be delivered ontotable I at the desired temperature after cooling in transit from the hot saws onto hot bed H from hot bed H onto roller line R", from roller line l't onto hot bed- H and to provide a sufficient time interval for the rails within the furnace to be fully equalized at the desired maximum treating temperature before discharge onto delivery table T the timing device A operates to close an electrical circuit which through various time delay relays performs as follows:

(1a) De-energizes motors 2|--21'a operating transfer dogs 26'26a so that no more rails can be delivered onto table T from hot bed H without however interfering with the actuation of the transfer .dogs delivering rails onto hot bed H (1b) De-energizes motor 3 terminating oscillation of the furnace rollers.

(2) Energiz es. magnetic . clutches 35 and 36 thereby clutching together the forward drive 'of all the rollers of tables T and T and furnace F.

(3) Energizes motors 29 and 30 and re-energizes motor 3 to forwardly drive all of the rollers of .Tables T T and furnace F.

Forward driving of 'the rollers of .tables I, T and furnace F continues until the rear end of the rails on table T clears switch means 31 thereupon switch means 31 operates to throw into the-motor field circuits of each motor 29, 3 and 30 an electrical resistance operative to slow down the rate of forward drive. When the rear end of the rail clears the projected beam of .light operating photo- sensitive means 38 or 39 at the entrance or exit end of furnace F the re-established light beam operates through suitable relay devices to set in motion the following sequence of operations, schematically indicated in Fig. 5.

(1a) Motors 29 and 3 are .de-energlzed terminating forward drive of the rollers of table T and furnace F. I

(1b) Motor 30 is de-energized but time delay switch means 40 in the 'circuit operates to delay the de-energization of motor 30 until the rear end of the rails has cleared switch 40.

(20.) Magnetic clutch means 35 and 35 linking together the drives of the rollers on tables T and 'I with that of the rollers in furnace F are de-energized.

3a and 3b) Motors 4 and 5' actuating inlet and outlet doors 4 and 5, respectively, are energized to close'the said doors 4 and 5.

(4) Magnetic clutch 45 is energized and motor 3 is energized through time delay relay 45 and oscillating switch means 41 to drive shaft 2 and rollers I of furnace F in slow forward and reverse directions through a determined angle of rotation in each direction to oscillate rollers This particular oscillating means is old per se in.

the art and accordingly needs no further description. (5) Timing device A is reset to a new time interval at the conclusion of which the above identified sequence of operations automatically be clear-that as a safety measure table '1 must' be emptied of rails and before any rails are fed into or out of furnace F the inlet and outlet doors 4 and 5 respectively must be fully opened. We therefore provide on table T. a switch means 48 which is operated as schematically illustrated in Fig. 4 to break the control circuit at 4! closed by timer A as long as any rails remain on table 'I. We also provide switch means 50 and 5| operative in conjunction with doors 4 and 5 respectively to break the electrical circuit closed by switchmeans A whenever doors 4 and 5 are not in the fully opened position, and to be closed when doors 4 and 5 are in fully opened position. With this arrangement even though timer means A operates to close the circuit of Fig. 4 at the end of a determined time interval none of the succession of operations to be set in motion thereby. can be initiated until switches 49, 50 and 5| are closed and the circuit completed.

We prefer to leave the operation of opening doors 4 and 5 at the end of the determined time interval to the manual control of anoperator in pulpit P for the reason that there are many variables in time and temperature in the delivery of rails onto table T for introduction into furnace F and accordingly it is inexpedient to provide for the automatic opening of . doors 4 and 5.

-With the above brief description in mind reference now should be made to Figs. 4' and 5 wherein we have schematically illustrated the co-operative relation of the electric circuits and the apparatus elements of the present invention. Fig. 4 schematically illustrates what may be identified as the feeding and discharging cycle and Fig. 5 schematically illustrates what may be identified as the oscillating cycle.

At the end of the determined time interval set on timer A, the operator in pulpit P", if therails on approach table T are ready for introduction within the furnace F, manually energizes motors 4and5'toopendoors4and5totheirfully table T emptied of rails the control circuit closed by timer A operates through various time delay relay devices D D and D upon the various instrumentalities connected to these said devices D, D and D by straight lines, to perform the various functions indicated under numerals I, 2 and 3, which are as follows:

(10 and b) The motor 21 energizing the set of transfer dogs operating to transfer rails from hot bed H to table 'I is de-energized so that no more rails can be located on table T Motor 3 and oscillating means 45 and 41 are each de-energized terminating oscillation of furnace rollers l.

(2a and b) Magnetic clutches 35-35 are energized linking together the respective drive shafts of the rollers of tables T '1 and furnace 1''.

(3a, b and c) Motors 29, 3 and 30 areenergized for full speed forward driving of all rollers of tables T '1 and furnace F.

The forward movement of the rails thus initiated into, through and out of furnace F continues until the rear end of the rail (entering or leaving the furnace) clears the projected beam of radiation between photo-sensitive means 34 and 39. The re-established beam of radiation between these devices actuates relay device 53 which closes a second control circuit and operates through suitable time delay relays D, D, D and D to perform the sequence of operations indicated in Fig. 5.

The first operation involves de-energization of motors 29, 3 and so that forward driving of the rail is terminated. The second operation involves de-energization of the magnetic clutches and 36 so that the respective drive shafts of the rollers of tables T '1 and furnace F are separated. The third operation involves energizetion of motors 4 and 5 to close doors 4 and 5 thereby opening switches 50 and 5| in the control circuit of Fig. 4. Switch 48 in the first control circuit of Fig. 1 becomes opened when the rails delivered onto table 2 are passed over switch 4.. The fourth operation of this second control circuit involves the re-energizing of motor 3 through oscillating switch means 41 and the energizing of magnetic clutch 45 to engage shaft 2 for slow speed forward and reversed oscillation. The fifth operation of this second control circuit of Fig. 5 involves the resetting of timer A. The-status quo of this arrangement will remain until doors 4 and 5 are manually opened by the operator in pulpit F at or about the end of the determined time interval reset on timer A. When the determined time interval reset under operation 5 on timer A expires, the closing of the control circuit of Fig. 4 will not affect this status quo until switch 49 is closed and table '1 is cleared of rails even though doors 4 and 5 are in fully opened position.

The various apparatus elements of the electrical control system, per se, form no part of the present invention and are separately old in the art, and therefore need not be specifically described. The schematic diagrams of Figs. 4 and '1 showing the operative assembly of these apparatus elements for the p rp ses of the present invention is believed to be ample disclosure to those skilled in the metallurgical art to enable reproduction of the same without undue experimentation by those skilled in the electrical art. In view thereof, it is apparent that the present invention may be widely modified without essentially departing from nature and scope thereof,

and all such modifications and departures are means to oscillate the rollers of the roller bottom in forward and reverse drives, an approach table located adjacent the inlet end of the furnace and a delivery 'table located adjacent the outlet end of the furnace, each of said tables being provided with rollers aligned with the rollers of the said roller bottom to feed rails into the furnace and to receive rails discharged from the furnace respectively, separate drive means for each said table to forwardly drive the table rollers, clutch means to engage the table and furnace forward driving means to synchronize the forward driving of all the rollers, and means to selectively energize the said clutch means, the said forward driving means of the tables and furnace rollers and the oscillating means of the furnace rollers to obtain a periodic forward driving of all the rollers with an accompanying periodic feeding of rails into the said furnace from the approach table, a periodic advancement of the rails through the furnace and a periodic discharge of 2. Apparatus for the heat treating of rails and similar elongated steel articles comprising in combination an elongated furnace having inlet and outlet openings in opposite ends, an approach table adjacent the inlet end and a delivery table adjacent the outlet end, the bottom of said furnace and each said table being provided with rollers and separate drive means therefor adapted to progressively feed said articles from the approach table into said furnace, through the said furnace and onto said delivery table, clutch means to synchronize the forward driving of all the rollers, means to oscillate the furnace rollers in forward and reverse drive,'movableclosure members for said inlet and outlet furnace openings and means energized ,by the movement of said closure members to fully open position to deenergize the oscillating means and to energize said clutch means and to energize the said forward driving means of all said rollers, means to de-energize the forward driving means and the said clutch means when the rear end of the said article passes into the said furnace, and means to return said closure members to closed position and to re-energize said oscillating means when said closure members are moved from fully opened position. 4

3. Apparatus for the heat treating of elongated steel articles which comprises an elongated furnace having a length several times the length of said article and a width several times the width of said article and provided with means to heat the furnace interior over substantially the entire length and width to a desired operating temperature, inlet and outlet openings in opposite end walls of the said furnace and movable closure members for each said opening, a roller bottom for said furnace adapted to advance rails through the furnace between opposite inlet and outlet openings, means to forwardly drive the rollers of said roller bottom and means to alternately drive the said rollers in forward and reverse directions to oscillate the said rollers, means to periodically feed a plurality of articles in side spaced relation through the inlet opening, means to simultaneously energize the forward driving means to advance articles then in the furnace towards the outlet opening a distance approximating their length means to deenergizethe forward driving means when the rear end of the said articles being fed into the furnace pass a determined point in the furnace, and means actuated by the termination of said forward driving to energize said oscillating means.

4. An elongated roller bottom furnace having inlet and outlet openings in opposite end walls and movable closure members for said openings, the roller bottom of said furnace being provided with a forward driving means to advance work pieces through the furnace from inlet to outlet openings, and an oscillating driving means, means to automatically energize the said forward driving means when the said closure members are moved to afully open position, means, located within the interior of the furnace adjacent the inlet and outlet openings to de-energize the forward driving means when a work piece reaches a determined position within the furnace and to move the said closure members from open to closed position, means to automatically energize said oscillating drive means when the said closure members are in closed position and means manually operative to move the said closure members to open position to re-energize said forward drive means.

5. In the combination ofv claim 4, approach and delivery tables adjacent inlet and outlet openings, means to feed work pieces from the approach table into the furnace and to receive work pieces on said delivery table as they are discharged from the said furnace, means energized by the location of work pieces on the delivery table to prevent energizing of said forward driving means of said furnace and to permit energizing of the forward driving until the said delivery table is clear of said work pieces, and means to synchronize the feeding of work pieces into the furnace from the approach table with the forward driving means of the said furnace to maintain a desired end spaced relation between the said work pieces within the said furnace.

6. Heat treating apparatus for rails, rods, bars and similar elongated steel articles, comprising an elongated furnace having inlet and outlet openings in opposite end walls and a roller bottom adapted to carry said articles through the furnace from the said inlet to the said outlet opening, means to forwardly drive said roller bottom, means to drive said roller bottom alternately in forward and reverse directions, means to heat the interior of the furnace to a desired operating temperatin'e, approach and delivery roller tables located respectively adjacent inlet and outlet openings, means to forwardly drive the rollers separately to feed articles into the furnace and to carry articles away from the furnace, clutch means to engage the forward driving means of 'each table and the furnace to synchronize the forward driving thereof, movable closure membars for the inlet and outlet openings of the furnace, manually operative means to move said closure members to open position, switch means operative when the said closure members are in fully open position to close an electrical circuit adapted to de-energize the alternate forward and reverse drive means of the furnace rollers, to energize means engaging said clutch means and to energize each of the forward driving means of in the sequence stated.

7. Apparatus for the heat treating of rails, rods,

.bars and the like elongated steel articles comprising in combination an elongated roller bottom furnace having a length several times the length of the article and a width several times the width of the said article and having inlet and outlet openings in opposite end walls, the said roller bottom being adapted to carry said articles through the furnace between said inlet and outlet openings and being provided with means to forwardly drive the rollers and means to alternately drive the rollers in forward and reversedirections, and approach and delivery roller tables located respectively adjacent said furnace inlet and outlet openings and the said table rollers respectively being adapted to feed articles into and to receive articles from the said furnace, means to separately drive said table rollers in forward direction, clutch means to engage the forward driving means of the furnace to the forward drive means of each table, closure members for each furnace opening, manually operative means to move said closure members to fully open position, means operative when the said closure members are in fully open position to de-energize the alternate forward and reverse drive means of the furnace rollers, to energize the said clutch means and to energize the forward drive means of the furnace and each table rollers in the sequence stated and at determined time intervals, switch means located on the approach table to slow down the forward drive means of each said rollers when articles feeding therefrom into the furnace pass a determined location thereon, and means to deenergize the forward drive means of each said rollers when the article fed into the furnace reaches a determined position therein, to de-energize said clutch means, to move the said closure members to closed position and to re-energize said alternate forward and reverse driving of the said furnace rollers, in the sequence stated and at determined time intervals.

8. Apparatus for the heat-treating of rails and similar elongated steel a t cles co pris ng a roller bottom furnace substantially rectangular in cross-section having a length and width several times the length and width of the article and having inlet and outlet openings in opposite end walk with the roller bottom adapted to convey articles endwise through the furnace from inlet to outlet opening, means to forwardly drive the rollers of the said roller bottom to convey the said articles from the inlet towards the outlet openin8. means to alternately drive the said rollers in forward andreverse directions, approach and delivery roller tables adjacent the inlet and outlet openings respectively having the roller members thereof in alignment with the furnace rollers and in a location adapted to feed articles into the furnace and to receive articles from the furnace respectively, means to forwardly drive the rollers of each said table, movable closure members for the said inlet and outlet openings, means to move the said members to open and to closed positions, means operative when the said members are in fully open position to complete an electrical circuit including means to de-energize the alternate forward and reverse drive of the furnace rollers and to energize the forward drive means of the furnace rollers and the rollers of each said table, means on the approach table to slow down the speed of said forward drive when articles feeding therefrom into the furnace pass a determined position thereon, means in said furnace to de-energize the forward drive means of the furnace and approach table when the rear end of the article entering or leaving the furnace passes a determined point adjacent inlet and outlet openings respectively, to energize the said means operative to move the said closure members to closed position and to re-energize the said alternate forward and reverse drive means of the furnace rollers, means on the delivery table to de-energize the roller drive means thereof when the said articles arrive at 'a determined location thereon, and meansto render inoperative the closing of said electrical circuit by the opening of said closure members until the said articles have been removed from said delivery table.

9. In the combination of claim 8, time controlled means to periodically close said electrical circuit, and means to manually operate said means to move the said closure members to fully open position. I

10. In the combination of claim 8, means to align said articles in side spaced relation upon said approach table in end spaced relation to the rear end of articles within said furnace.

11. In the combination of claim 8, means to cool the ends of said article at a more rapid rate than the portions intermediate the saidends,

ALBIN G. W'I'I'I'ING. JOHN mm mm

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