US1784812A - Furnace and conveyer therefor - Google Patents

Description

Dec. 16, 1930. R. s. COCHRAN 2 FURNACE AND CONVEYER THEREFOR Filed April 25, 1928 3 Sheets-Sheet l I N V EN TOR.

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Dec. 16, 1930. R. s. COCHRAN 1,784,812

FURNACE AND CONVEYER THEREFOR Filed April 23, 1928 3 Sheets-Sheet 2 Dec. 16, 1930. 5 CQCHRAN 1,784,812

FURNACE AND GONVEYER THEREFOR Filed April 23, 1928 3 Sheets-Sheet 3 I N VEN TOR.

AA: ATTORNEY.

/PM/ (flaw/m1 Patented Dec. 16, 1930 UNITED STATES PATENT OFFICE RALF S. COCHRAN, OF TOLEDO, OHIO, ASSIGNOR TO THE SURFACE COMBUSTION CO., INCORPORATED, OF TOLEDO, OHIO, A CORPORATION OF NEW YORK FURNACE AND CONVEYER THEREFOR Application filed April 23,

This invention relates to heat t reating furnaces and conveyers therefor and more particularly to a continuous furnace for heattreating flat material such as steel sheets and the like.

The more common type of conveyer for use in furnaces of the continuous type wherein sheet steel is to be heat-treated embodies a bed of power driven disks or rollers. Conveyers of this type, however, cause objectional pitting and scratching of the sheets. Furthermore because of the numerous roller shafts which project through openings in the furnace side walls it is a matter of great practical difliculty to prevent infiltration of air into the furnace through said openings or, in other words, it is a matter of great practical difliculty to maintain a neutral furnace atmosphere such as will prevent the formation of scale on the sheets because of the air which filters in through said openings. Moreover, infiltration of air at pointsin such relatively close proximity to the sheets is especially objectionable as will be readily appreciated.

The present invention has among its obj ects to reduce or entirely eliminate pitting and scratching of the sheets by employing a conveyer which periodically ently lifts the material from a supporting E longitudinallyextending rails, translates it a g1ven distance, and then gently deposits it on.the rails and to reduce to a minimum the number of openings through which air might find 'entry into the furnace by supporting and actuating the conveyer in an improved manner.

. The various features of novelty and invention will more fully appear from the detailed description in connection with the accompanying drawings forming part of the specification.

In the accompanying drawings, Fig. 1 is a vertical longltudinal section through the improved furnace; Fig. 2 is in part a front elevation'of the charging end of the furnace, certain operating mechanism at the front thereof being omitted, andin part a transverse section therethrough on lines 2-2 of Fig. 1, the view as a whole being on an ened comprising 1928. Serial No. 272,020.-

larged scale as compared with Fig. 1; Fig. 3 is detail view showing the preferred form of connection between the side arms and cross beams; Fig. 4 is an end elevation of the conveyer actuating mechanism appearing at the left-hand end of thefurnace in Fig. 1; Fig. 5 is a view showing the cams which impart vertical and horizontal movement'to the conveyer mechanism; Fig. 6 is a sectional view showing how the rail sections may be supported to provide for expansion and contraction; Fig. 7 is achart showing in graphic form the cycle of movement of the movable set ofrails, and Fig. 8 is a section through the burner.

Like reference characters denote, similar parts throughout the several views.

The heating chamber is a relatively long box-like afi'air substantially closed all around against the infiltration of air and exit of spent heating gases except at its opposite ends where relatively restricted openings 10 and 12 are formed for ingress and egress of the work to be heated. The chamber is fired by explosive gaseous mixture introduced thereinto by tiers of burners 31 and 33 located 'n the side walls of the chamber, the mixture b ing formed and supplied to the burners by any appropriate means not shown. As is well understood by those skilled in the art, an explosive gaseous. mixture is a h'omogenous mixture of fuel gas and air in quantitative proportion for complete or substantially complete combustion and such mixture must be discharged from the burners with a velocity in excess of the rate of propagation of inflammation through the mixture in order to prevent back-flashing into the burner. In order that the mixture may burn immediately after being discharged from the burner,- its velocity is reduced by expansion in a tunnel'35 formed as a reentrant portion in the furnace walls 38.

The highly heated gases of combustion enterthe heating chamber pro erdirect from said tunnels in an actively swlrling state and con-,

sequently stir up the atmosphere in the heating chamber as a whole. The end openings 10 and 12 are preferably at a level above the floor level of the heating chamber in order p to permit firing below the conveyer.

- spaced pedestals 18. Asimilar set Rising from the chamber floor is a series of piers 14 which extend in spaced relation in rows longitudinally and transversely of the chamber. Supported on the transverse rows of piers is a series of fixed cross beams 16 and upstanding from each beam are of pedestals 18' extends from a cross beam 16 posi- VI. Extending lengthwise of the chamber and I supported on the longitudinally alined fixed pedestals 18 and 18 1s a series of work-supporting rails 20, these rails preferably being made up of sections of a length to extend between adjacent pedestals.

The adjacent ends of the rail sections may be provided with downwardly extending lugs 22 for projection into a pocket in the pedestal as clearly shown in Fig. 6, a securing pin 24 being passed through the lugs and the side walls of the pedestal pocket. This construction provides for expansion and contraction of the rail sections in a simple manner and permits quick replacement of individual rail sections where necessary:

, The rails 20 preferably project through the door openings 10 and 12 at the ends of the furnace for an appropriate distance to enable the work to be readily entered in the furnace and to be removed therefrom. At the discharge end of the furnace the rails 20 referably slope downwardly as shown in Fig. 1 to facilitate the removal of the work. Depending in front of the door openings are flexible heat resisting curtains 25 and 26 respectively,

these curtains being provided to prevent as much as possible the entry of air into the heating chamber.

Posltioned for movement between the relatively fixed rails- 20 is a set of movable rails 28. These rails are supported on floating cross beams or saddles 30 from which rise pedestals 32 to the tops of which the rails 28 are secured preferably as shown in Fig. 6,

these beams forming part of a'bifilar suspen sion the side arms of which are indicated at 42. On the outside of the furnace at the front end thereof is positioned a similar crossbeam 30.

-The opposite ends of the cross beams may be provided with upwardly extending crank-like extensions or members 34 for the double purpose of shortening the length of the side arms orlinks 42 which support thecross beams or bars 30 and of lowering the center of grav ityof said beams. These crank-like exten' slons preferably extending intorecesses 36in thechamber sidewalls 38in order to prevent interference between said extensions and the laterally As shown, the rails 20 and 28 are U shapein cross section; This type of rail is preferred since the sides of ad acent rails do not offer any opportunity 6f the edges of the work, such as sheets, becoming jammed during the operation of the conveyer. Moreover,

such rails are strong for their weight, permit of easy securement to their supports and provide two parallelly "extending work supporting edges for each rail. The upright webs of the rails may be braced by ties extending therebetween at intervals as will be readily understood. Considerable clearance is provided between adjacent rails to provide, among other things, relatively free spaces through which the hot gases from below may reach the work' on the conveyer. It will, of course, be understood any other suitable form of rails may be used without de arting from the invention and that they may e made from any suitable heat resisting alloy.

The side arms 42 of the bifilar sus ensio'ns are supported outside of the furnace ut project there'intothrough passages 40 the tops of which are se'a'led against the infiltration of air by cover plates 41, the plates bein reciprocated as the side arms oscillate. T e connections between the suspension cross bars 30 and their side arms 40 are preferably of the line or knife edge type (see Fig. 3). This type of connection '0 viously eliminates lubrication troubles and what 1s just as important any tendency to lateral sway of the suspension as a whole is materially minimized. The upper ends o'fi'the suspension side arms 42 are pivotally. connected to individual crank-arms 44 which are secured to individual shafts 46. Theseshafts are mounted in suitable bearings which are secured to longitudinally extending side beams 48 which in turn are fixedly secured to upright beams 50 j which extend along the exterior of the furnace side walls 38. These beams may constilongitudinally of the furnace byacommon I connecting rod 56. On the two alined shafts 46 at the front of the furnace are provided additionalcrank arms58 to which are connected operating pitmen. 60. A pair of these pitmen 60 is provided, one at each side of the furnace. p

i Generally speaking themechanism forreciprocating the pitmen 60 to vertically reciprocate the mova 1e rails or members and for horizontally reciprocating the said rails may be of any suitable construction but,in order to effect the preferred relative movement between the two sets of rails, it is preferred tov employ a mechanism embodying cams. An example of such mechanism has been shown and will now be described.

Mounted in suitable standards 62 in front of the furnace (see Figs. 1 and 4) is a shaft 64 having a pair of crank arms 66, one arm for each pitman 60. Also mounted on the shaft 64 is a crank arm 68 having at its end aroller which is in operative engagement with a cam 70 mounted on a shaft 7 2. This shaft is supported in suitable hearings on standards 74 and constitutes the power shaft for rotating said cam. I have shown the shaft 72 as provided with a sprocket 75 with which any suitable driving means may be connected.

- It will now be readily understood that as the cam 70 is rotated it will cause the movable set of rails 28 to be vertically reciprocated.

For imparting horizontal movement to the rails 28 there is provided on the shaft 72 a cam 7 6. Mounted on a suitably supported shaft 78 is a crank arm 80 having at its end a roller which is inoperative engagement with the cam 76. Also mounted on the shaft 78 is a pair of crank arms 82. Links 86, one for each crank arm 82, connect the crank arms 82 with the ends of the cross beam 30' on which the rails 28 are supported outside of the furnace in front thereof. It will now be readily understood that rotation of the cam 76 imparts horizontal-reciprocating movement to thetmovable set of rails 28.

The cams 70 and 76 are so constructed that the relative movement between the two sets of interdigitated rails20 and 28 is as shown in the chart which constitutes Fig. 7. In the chart each space between the graduations represents equal degrees of rotation of the cam shaft 72. The middle horizontal line A indicates the plane of the fixed rails 20. It will be noted that the relative vertical movement of the movable rails 28 the locus of a point of which is represented by the line B, is uniformly constant on each side of the line A for a distance shown as amounting to a rotation of 75 of the cam shaft 72. Oneither side of the range of uniformly constant movement, the rail displacement is proportionallyv greater.

By causing the rails 28 to move relatively slowly and uniformly in a vertical direction, the work which is resting on the fixed rails 20 will be gently lifted therefrom and gently deposited thereon, thus not only avoiding violent shock to the operating mechanism at the moment the work is transferred from one set of rails to the other but also effectually minimizing or actually preventin pitting of the work such as sheets by protu erances or particles of forei matter on the work or rails which partic es or protuberances is forcibly impacted against't e work would cause pitting thereof. The cycle of movement shown in Fig. 7 is an important feature of the invention. weight of the movable rails by counter weights 90, adjustably secured on crank arms of interdigitated rails the one set of rails 20 being fixed with respect to the furnace and the rails 28 being relatively'movable. The fixed sets of rails constitute a bed or hearth on which the work or ware normally rests between periods of-translation and the movable sets of rails constitute'a work or ware elevating and translating frame, the hearth and frame being laterally discontinuous to permit the frame to move through the plane of the hearth or bed. The cam 70 imparts the vertical movement to the rails 28 and the cam 7 6'the horizontal movement. By reason of the fact that the movable set of rails is supported on bifilar suspensions, the cross bars of which are wholly within the furnace chamber, the number of parts subject to heat within the heating chamber is reduced to a minimum and what is of great practical importance, by suspending the movable rails in I prefer to counterbalance thethe manner shown and described, the num ber of openings in the furnace walls through which air may filter into the furnace is reduced to a minimum and heat losses by conduction through parts projecting out of the heating chamber are practically eliminated. It will, of course, be understood that the recesses 36 as well as the passages 40 for the side arms of the bifilar suspensions are of such dimensions as will allow the suspensions to freely oscillate.

7. It should be noted that by supporting the movable set of rails 28 in the manner indicated, the brick work of the furnace does not support the weight of the rails. This arrangement is an importantfeature of the 1nvention.

Formed in the furnace walls adjacent each burner 33 is a lighting port 37. which is, of course, normally kept closed by any suitable means not shown.

Various changes may be made in constructional features without departing from the spirit of the invention and within the purview of the appended claims.

What is claimed is:

1. The combination with a furnace chamber, of two relatively movable sets of interdigited work-supporting rails for progress ing work in step by step fashion through the chamber, upright openings in the chamber side walls, hangers extending through said openin s, means for coupling the lower ends v the upper ends of the hangers on the framework, and cross beams on which one set of the work-supporting rails is supported, the ends of the cross beams extending into said recesses and being seated in the lower ends of said hangers.

3. The combination with a furnace chamber, of longitudinally extending interdigitated work moving and supporting rails in spaced relation to the floor of the furnace chamber, a framework exteriorly of the furnace along the side walls thereof, movable means supported from said framework and coupled to one set of said rails, recesses within the furnace side walls wherein the coupling means are movable, and means for introducing1 burning fuel into the furnace below the mm s.

4. The combination with an elongated furnace'chamber, of a framework between which the furnace chamber is positioned, a series of upright open top passages in the chamber walls adjacent the frame-work and opening into the chamber above the bottom thereof, a work-supporting bed extending longitudinally of the chamber, a longitudinally extend ing work-elevating and translating means arranged in parallelism with said bed, hangers movably mounted in said passages and coupled to said means for supporting the same, and movable means carried by the upper part of saidframework and coupled to said hangers.

5. The combination with an elongated furnace chamber, of a framework substantially as high as the chamber side walls and between which the furnace chamber is positioned, 'a series'of parallel shafts mounted on the upper part ofthe framework, a crank arm on each shaft, a hanger on each crank arm projecting into the furnace chamber, a series of cross beams within the chamber, said beams being supported by opposite hangers, a series of longitudinally extending rails supported on said beams, means cooperating with said rails to support and translate materials through the chamber, and means for imparting material-translating movement to said hanger-supporting rails.

6. The combination with an elongated furnace chamber, of two series of cross beams within the chamber in spaced relation t6 the floor'thereof, one series, of which is movable, two sets of Ion 'tudinally extending rails supported by said of beams, each of said rails being composed of sections of a length to extend between the adjacent beams of a series, means for coupling the adjacent ends of the rail sections to the beams, said means comprising a beam saddle having a pocket, a removable pin extending across the pocket, and pocket-entering lugs on the ends of adjacent rail sections through which said pin passes to hold the rails in place.

7 In combination, a furnace chamber having work entering and discharging openings at opposite ends, a conveyer of the work lifting and translating type in line with said openings, said conveyer' being positioned above the floor of the chamber, and means extending upwardly through the furnace side walls for supporting the movable part of the beams one set by eachseries bars and movable through the plane of said hearth, means projecting upwardly out of the chamber for raising and lowering said cross bars, and means for imparting longitudinal reciprocatory motion to said frame.

9. In combination, a heating chamber. of tunnel form, a laterally discontinuous hearth extending lengthwise of the chamber above the floor thereof, a series of floating cross bars extending transversely of the chamber below the hearth, side arms for swingably supporting said cross bars, a laterally discontinuous ware elevating and translating frame supported on said cross bars and movable through the plane of said hearth, the ends of said cross bars being connected to their respective side arms by bearings of the knifeedge type, and means for imparting vertical and horizontal reciprocating movement to said frame. v a

10. In combination, a laterally discontinuous hearth, a laterally discontinuous ware elevating and translating frame movable through the plane of the hearth, a series of floating cross bars on which said frame is supported, means for raising and lowering said frame at a relatively slow uniform rate on either side of the plane of the hearth whereby to lift the ware from and redeposit it on the hearth with minimum impact, and

means for imparting horizontal reciprocation to said frame. 4

11. In combination, a laterally dlscontinuous hearth, a laterally discontinuous ware elevating and translating frame movable through the plane of the hearth, a series of floating cross bars on which said frame is frame.

12. Ina heat-treating furnace, the combination with a longitudinally extending work support and a longitudinally extending work moving member adapted to be moved from one side to the other of the .plane of said support and longitudinally thereof, of a swingable suspension to the lower end of which said member is supported, means for moving said member longitudinally at any desired rate, and means for moving said member perpendicularly through the plane of said support with negligible velocity, whereby said member may lift the work from said support and redcposit it thereon without substantial impact.

13. In a heat-treating furnace, the combination with a longitudinally extending work support and a longitudinally extending work moving member adapted to be moved from one side to the other of the plane of said support and longitudinally thereof, of a swing able suspension at the lower end of which said member is supported, means for moving said member longitudinally at any desired rate and means for moving said member perpendicularly through the plane of said support with negligible velocity, whereby said member may lift the work from said support and redeposit it thereon without substantial impact, said member after being moved through said plane and before the limits of its vertical stroke is reached being adapted to be started on its longitudinal stroke.

14. In combination, a structure forming a box-like heating chamber having openings at opposite ends for the ingress and egress of the work to be heated, a perforated work support extending longitudinally within said chamber intermediate the top and bottom thereof, upper and lower tiers of burners for burning explosive gaseous mixtures tioned in the opposite sidewalls of the 0 amber for introducing thereinto transversely of the chamber above and below said support a plurality of streams of actively swirling highly heated gases of combustion, a laterally discontinuous work-moving frame movable through the plane of said support, and

means extending transversely of the chamber below said work support tendin to prevent free flow of fluid medium lengt wise of the space below said support.

15. In a continuous heat-treating furnace,

. the combination of a structure forming an elongated heating chamber substantially closed at its opposite ends where restricted openings are provided for the ingress and egress of the workto be heated, a stationary work-supporting bed comprising longitudinally extending laterally spaced rails abovethe floor of said chamber, means for introducing heating gases below said bed, a work moving frame comprising longitudinally extending laterally spaced rails movable between the stationary rails, means extendin upwardly.

from opposite sides of the frame or movably supporting it, means wholly outside of said structure for vertically reciprocating said means, and means for longitudinally reciprocating said frame.

16. In a continuous heat-treating furnace, the combination of a'structure forming an elongated heating chamber substantially closed except at its opposite ends where restricted openings are provided for the ingress and egress of the work to be heated, said openings being above the floor of the chamber, a stationary work-supporting bed comprising longitudinally extending laterally spaced rails above the floor of said chamber,

a work-moving frame comprising longitudinally extending laterally spaced rails movable between the stationary rails, means projecting upwardly from the frame intermediate the ends thereof for movably supporting it, means wholly outside of said structure for supporting said means, and means for reciprocating said frame longitudinally and vertically.

17. In a continuous heat-treating furnace the combination of a structure forming an elongated heatin chamber, a stationary work-supporting bed comprising longitudinally extending laterally spaced rails, a floating work moving frame comprising longitudinally extending laterally spaced rails movable between the stationary rails, a plurality of upwardly extending side arms for pivotally supporting said frame, bearings of the knife-edge type between said arms and frame whereby to minimize lateral sway of said frame, means wholly outside of said structure for vertically reciprocating said sidearms, and means. for longitudinally reciprocating said frame. I

18. In a continuous heat-treating furnace, the combination of a structure forming an elongated heating chamber, a statlonary work supporting bed. comprising longltudi-i nally extending laterally spaced rails above the floor of the chamber, a laterally unconfined work moving frame in said chamber, said frame comprising a bed of longitudlnally extending ralls in spaced parallel relationthe rails being positioned for movement between the stationary rails, a series of upright links pivoted at their lower ends to sald frame intermediate the. ends thereof, bell cranks outside of said chamber to which the upper ends of said links are pivoted, individual shafts for each of said bell cranks, means for rocking said bell cranks in unison including a cam mechanism at one end of said structure, and means for longitudinally reciprocating said frame.

19. In a furnace, the combination of a work bed, a work-moving frame associated with said bed, a series of swingable links for supporting said frame, the connections between said links and frame each comprisin a loop at the. lower end of each link, and a caring of the knife-edge type projecting laterally from the frame and seated in said loop.

20. In a furnace, the combination of a work bed, a work-movin frame associated with said bed, a series of inks for supporting said frame, supports to which the upper ends of the respectlve links are pivoted, the connections between said links and frame each comprising a loop at the lower end of each link, and a bearing of the knife-edge type projecting laterally from the frame and seated in said loop.

In testimony whereof I aflix my signature.

RALF S. COCHRAN.

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