US2406821A

US2406821A - Heat processing machine

Info

Publication number: US2406821A
Application number: US432541A
Authority: US
Inventors: Vernie A Fox
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-02-20
Filing date: 1942-02-20
Publication date: 1946-09-03
Anticipated expiration: 1963-09-03

Description

Sept. 3, 1946. vQA. Fox

HET PROCESSING MACHINE Filed Feb. 20, 1942 4 Sheets-Sheet l muw mi.

SH QN NN EN l (Ittornegs Sept. 3, 1946. v. A. Fox

HEAT PROCESSING MACHINE Filed Feb. 20, 1942 inventor Zx 4 Sheets-Shveet 2 Gttcrnegs Sept. 3, 1946. v FOX 2,406,821

HEAT PR-CESS ING MACHINE Filed Feb. 2o, 14942 4 sheets-sheet s Gttornegs sepf.3,1946.h v A FOX' 2,406,821

HEAT PROCESSING MCHI??? Filed Feb. 20, 1942 l 4 Sheets-Sheet 4 r/ 17'); L`4- ra Q l v t\ y I n 1 G L V UL g Suventor N i We Mm g. 'y Y l @M2 @LL ttomegs Patented sept. 3, 1946 UNITED STATES i PATENT OFFICE 2,406,821 1 v HEAT PROCESSINGMACHINE vernie A. Fox, Denim, Mich. Application February 20, 1942, Serial No. 432,541

6 Claims. 1

This invention relates to heat processing machines, and in particular to conveyor-type heat processing machines,

One object of 'this invention is to provide a heat processing machine for automatically conveying and heat-processing sheets or plates of material such as lithographed plates.

Another object is to provide a heat processingr machine wherein the sheets of material to be heated are conveyed in carriers through an oven wherein they are subjected to heated air currents proceeding upwardly and downwardly in a zigzag path in the opposite direction to the direction of travel of the sheets.

Another object is to provide a heat processing machine with an endless conveyor which is normally driven from a source of power which also drives other machinery, such as coating and/or printing machinery, automatic means being provided for connecting in an auxiliary source: of power when this machinery ceases operation;

Another object is to provide a heat processing machine having an oven into which articlesare conveyed upwardly at the inlet and downwardly toward the outlet, thereby conserving heat by reducing the escape of the heated air normally occupying the upper portion of the oven.

Another object is to provide aheat processing machine as set forth in the previous object wherein means is provided at the outlet end of the machine for momentarily advancing the lower edge of the sheet faster than the upper edge so that when the sheet falls as it nears the end of the conveyor it will not be damaged by slicing or buckling.

Another object is to provide a heat processing machine having a travelling conveyor with sheet carriers spaced at intervals therealong, these sheet carriers being constructed and arranged with elongated central supports to convey either large or small sheets without leaving the lower edge unsupported at its ends.

Another object is to provide a heat processing machine including an oven having an air circulating system and a heating system, automatic means being provided for delaying the starting of the heating system a predetermined time period after the starting of the air circulating system, so that all explosive or inflammable gases will be automatically cleared out of the oven before heating commences. i

Another object is to provide a carrier forsheets of material consisting of a framework of Vrods or bars adapted to be carried by a conveyor and having provisions for leaving portions of the 2 lower edge accessible for engagement by other portions "of the machine yet providing an elongated central support for several different sizes of sheets or plates.

Another object is to provide a heat processing machine as set forth in the preceding objects wherein cooling devices are provided adjacent the outlet of the machine for cooling the heated sheets or plates being processed by the machine.

in the drawings:

Figure 1 is aside elevation, partly in section, of the outlet endof` a heat processing machine according to a preferred embodiment of the present invention.;

Fig. 2 is a view similar to Fig. l, but showing the inlet end andadjacent machinery;

Fig. 3 is a horizontal section along the line 3-3 in 1, with the sheet carriers removed to disclose the construction more clearly;

Fig. 4 is a horizontal section similar to Fig. 3 but taken along the line 4-4 in Fig. 2;

Fig. 5 is across section along the line 5--5 in Fig. 1;

Fig. 6 is aside elevation of a portion of a conveyor `chain `with the sheet carriers mounted thereon; f

Fig. 7 is a horizontal section along the line 1`|A in Fig. 6; y x

Fig. 8 is a vertical section along the line 8--8 in Fig. 6;

Fig. 9 is a detail view of the clutch shown in the lower central portion of Figs. 2 and 4;

Fig. lO is a diagrammatic side elevation of the conveyor at the outlet end of the machine, showing the means whereby the lower edge of the sheet or plate is momentarily advanced more rapidly than the upper edge so as to make it fall without injury;

Fig, l1 is a circuit diagram of the electrical, fuel and air circulation systems.

General arrangement In general, the heat processing machine of this inventori includes an oven within downwardlyinclined ends for conserving heated air which is circulated through the oven by fans or blowers. An endless conveyor moves through the oven and is provided with spaced sheet carriers at intervals therealong. The sheet carriers consist of open frames (Fig. 5) having gaps at the bottom thereof to permit engagement of the `sheet with other conveying apparatus yet having a downwardly depending central supportl for the mid-portion of the lower edge of a large sheet or the end portionof a smallsheet, thereby the conveyor, together with automatically operative mechanism which immediately connects the auxiliary motor when the main motor is halted, A

thereby permitting the printing and/or coating machines to be operated intermittently while the on a shaft 3l.

conveyor operates continuously over a given period of time.

The spacing of the carriers along the conveyor and the mounting of the carriers at their opposite ends on a pair of parallel conveyors enables the central portions to be maintained compara"- tively free from obstructions. Heaters and blowers are provided for circulating heated air upward and downward between the sheets on their carriers in a zigzag path, this heated air being finally exhausted from the oven by an exhaust fan located near the inlet of the oven, thereby causing the heated air to travel in the opposite direction to the conveyor and sheets. An electrical circuit is provided whereby the heatersare delayed from starting in operation a predetermined time after the fans are started, so that the latter may remove any inflammable gases which may have collected within the oven, thereby preventing accidental fires or explosions from such gases being ignited by the heaters. Cooling fans are provided adjacent the outlet of the machine for cooling the sheets so that they may be removed by hand if desired.

An auxiliary conveyor is provided at the outlet end of the machine for temporarily moving the lower edges of the sheets ahead of the upper edges, so that as the carriers swing downward at the ends of the conveyor the sheets will fall gently and without shock, thereby preventing damage to the sheets and possible injury to the machine and operators. vided adjacent this auxiliary conveyor for carrying away the sheets as they are unloaded from the oven conveyor.

Machine driving mechanism Referring to the drawings in detail, Figs. 1 to 4 inclusive show the heat processing machine of this invention as consisting of an oven generally designated I0 containing an endless conveyor generally designated II having sheet carriers generally designated I2 mounted thereon and moving in an orbital path, An auxiliary conveyor, generally designated I3 and a withdrawal conveyor generally designated I4 are provided adjacent the left-hand or outlet end of the machine (Figs' 1 and 3). Air circulation fans I5 are provided for circulating air heated by burners I6 through the spaces between the sheet carriers I2 and in a direction opposite the direction of travel of the conveyor II toward an exhaust fan I I located near the inlet I8 of the oven I0 (Fig. 2).

Also located adjacent the oven inlet `I8 is a printing machine I9, a coating machine 2li and a feeder 2I located therebetween. The machines I9, ZGand 2l in themselves form no part of the present invention, except as to their main driving' motor 22 which cooperates with an auxiliary driv- A withdrawal conveyor is rproing motor 23 to drive the machines i9, 20 and 2| together with the conveyor I l by the motor 22, or optionally to drive the conveyor I I alone by means of the auxiliary motor 23. The drive from the main motor shaft 24 is conveyed to the shaft 25 of the machine I9 by a belt or chain 26 interconnecting the pulleys or sprocket 21 and 28 (Fig. 4).

The shaft 25 carries a pulleyor sprocket 29 which drives a pulley or sprocket 30 by means of a chain or belt 3|. The sprocket or pulley 3G vis loosely mounted upon a shaft 32 mounted in brackets 33 and drives the shaft 32 through a jaw clutch 34. The shaft 32 carries a bevel gear 35 meshing with a bevel gear 36 mounted The latter is connected by lmeans of a jaw clutch 38 to the auxiliary driv ing motor 23 by means of a sprocket or pulley 39 mounted loosely upon the shaft 37. The shaft 3'!A y,extends lengthwise of the machine and the pulley or sprocket 39 is driven by a chain or belt 4I from a pulley or sprocket 42 mounted on the shaft 43 of the auxiliary motor 23. The shaft 3l also carries a sprocket or pulley 44 driving a -sprocketor' pulley 45 by means of a chain or belt 46. The sprocket or pulley 45 is mounted upon the input vshaft, 4l of a reduction gear set 48, the output shaft 49 of which is mounted transversely in the machine frame members 5i] and carries a pair of sprockets 5I meshing with the conveyor chains 52. The shaft 3l (Fig. l) is rotatablyv supported in brackets 53 mounted on the oven supports 54 and upon the outlet support 55, and at its outer end carries a sprocket or pulley 56 driving a sprocket or pulley 51 by meansy of-a chain or belt 58. The sprocket or pulley 5l is mounted upon the input shaft 59 of areduction gear set 60, the output shaft 5I of which' carries a pair of sprockets 62 driving the outletends of the main conveyor chains 63 of the conveyor I l, the inlet ends of which are driven by thefsprockets 5I upon the shaft 49. The shaft Sigis likewisely mounted transversely upon the outlet frame members E4. The shaft 62 also carries abair of auxiliary conveyor sprockets 65 driving the sprockets S6 vupon the shaft 61 by means of the belts or sprocket chains 69 of the auxiliary conveyor I3 (Fig. 3). The auxiliary Y conveyor-shaft 6l is mounted in brackets 69 supported upon the outlet frame members 64. The latteralso carry brackets "IG rotatably supporting the shafts ,'II carrying pulleys or sprockets l2 driving the belts or chains 73 of the withdrawal conveyor I4. The latter is also provided with an intermediate sprocket or pulley 'I4 mounted upon a shaft 15 (Fig. l0)v supported in brackets 'IG and driving an intermediate belt or chain TI.

The jaw clutches 34 and 38 are of similar construction'in that they arearranged to drive their particular shaft in one direction and to slip relatively thereto in the opposite direction. Accordingly a single description sufces for each of the clutches 34 and`33 (Fig. 9), the clutch 38 being selectedfo'r'this purpose. The clutch 38 consists ,collar BI `'pinned as at 82 to the shaft 31.

of a drivingimernber "e8 connected to the pulley 39 and having jaw portions 'I9 interconnected by inclined portions 89. The pulley 19 is loosely rotatableup'on "thel shaft 31, and seats against a Cooperatin'gwith the clutch member Iis a clutch member 83 having driving shoulders or jaws 84 interconnected-by inclined portions 85, the clutch member 83" being keyed or splined to the shaft 3l' as at 85,) so as to be sldable longitudinally i along the shaft'l by means of a spring 8l seated against a collar 88 pinned as at 89 to the shaft 31 vIn this manner eachl clutch 34 or 38 drives its shaft 32 or 31 in one direction butslips and clicks withoutfdriving vconnection when the drive is in the opposite direction. Y

The purpose of the clutches 34 scribed in connection withthe operation of the machine, is to perrntthe conveyor I I tobe driven Y normally 'by the main driving motor 22 when Oven construction The oven I!! is an elongated box-like structure with side walls 9| (Figures 3 and 5), a-top 92, and a bottom 93. The oven also has inlet and outlet ends S4 and 95 respectively (Figs. 1 and 2). The inlet end 94 for the purpose of conserving heat is directed downwardly toward the inlet lil. The inlet end 94 is provided with a port 96 communicating with the conduit 91 in a casing s3 containing the exhaust-fan I1 for creating a suction to remove air which has traversed the oven and to discharge this air into the discharge conduit 99.

The outlet end 95 of the oven I 0 (Fig. 1) is provided with an outlet |00 communicating with a hood or vestibule IGI likewise for the purpose of conserving heat and minimizing the escape of the heated air. Baies |62 are distributed at intervals along the interior of the oven Iii for impeding the direct passage of the air from one end of the oven to the other so as to force it' downwardly between the sheets 96 as they are carried along by the conveyor II upon the carriers I2. One of the walls 9| of the oven is provided with doors HB3 for permitting access to thel burners I6 and other portions of the interior of the machine. v a

The burners I6 are shown as gas burners but other types may obviously be employed. Theair heated by the burners is circulated by the fans or blowers I5, which are 'located in casings |14 having inlets or intakes IBEAandoutlets or exhausts |06. The blowers I5 are operated by shafts Ic'imounted in brackets |08 (Fig. 5) secured to the walls 9|. The shafts |1 carry pulleys |69 driven by belts III) from pulleys III upon the shafts I I2 of motors I I3. The latter are mounted upon brackets I I4 beneath the longitudinal frame members II5 interconnecting the oven supports 5d. The brackets I|4 are also matched by corresponding brackets i IB on'the opposite side of the machine (Fig. 5) and these together support the angle guide rails ||1 upon which the conveyor chain E3 travels on its return path.

The'interior oi the oven is likewise provided with angle guide rails I i8 which support the conveyor 53 in its travel through the oven, and these guide rails `I Ill` are inclined downwardly at the opposite ends ofthe oven. Cooling fan motors H9 provided with fans |20 incasings |2I are located near the outlet end 95 of the oven so as to cool the sheets or plates 90 as they emerge from the vestibule or hood Near the oven outlet Icll the guide rails II8 are supported by a cross member 22 and elsewhere within the oven by cross members |23 (Fig. `5). The latter areconnected to longitudinal angle members, |24 and also carry spaced longitudinal members |25 between `which the air may `The conveyor II and carriers |2`include the conveyorlchains E3 mounted upon the guide rails H8 and ||l as previously described. rThe conveyor chains E3 consist of links 225 and |21 pivotally connected to` pivot pins |28 carrying rollers |29 which roll along the-top edges of the guide rails II'I` and I lil. The pivot'pins |23 are providedon one side with heads `|29 and on the other side areheld in place by cotter pins |33. Mounted adjacent thelinksIZl are angle members `|3| which extend out over the links |21 and provide rests for the lower edges of the sheets or plates 3|] which form the work pieces handled by the machine. Adjacent the opposite links |25 are mounted channel members |32 having aligned apertures |33 and |34 (Fig. 8) through which pass the side portions .|35 of the carriersl2. These side portions |35 are biiurcated as at |35 and spread apart after their insertion so as to prevent their accidental withdrawal.

The side portions |35 are bent inwardly to form top portions |33 and |31. The top portion |31 is bent downwardly in a diagonal portion |38 (Fig. 5) `to the portion |35 in any suitable way, as by sp-ot welding; The top portion |38 is bent diagonally downwardly in a portion Mb which is secured at lthe top portion le! to the diagonal portion |38. A diagonal portion |22, also secured at the top portion |l|3 to the diagonal portion 38, continues downwardly to a junction at the top portion |44 with the other side member |35. Secured at its opposite ends M5 to the diagonal members |38 and |62 is a vU-shaped downwardlyextending frame |46 having side portions |41 and a cross portion Idd at thebottom thereof. Secured to the bottom portion M8 at the corners oi the frame lli@ are sheet'supports liel. The sheet supports are inclinedupwardly as at Mila (Fig. 6), and `serve to support the lower edges of thesheets 9d. j

The carriers i2 are ,thusspaced at `intervalsy along `therchain 63 and are inclined upwardly so that the sheets or plates di! rest in inclined positionsas they travel through the oven (Fig. 6). The downwardly extending `frame its with its supportsk |49 enables sheets smaller than theV maximum size sheets to be conveyed, hence there is no necessity for changing the carriers l2 for diiierent sizes of sheets. Moreover, the open spaces between the side members 35 and |46 permit the lower edges of the plates to be engaged by the auxiliary conveyor 65| (Fig. l0) which passes through these spaces and serves to advance the lower edges of the sheets 9S ahead of their upper edges as previously described above.

Heating, driving and air circulating systems` Figure 11 shows diagrammatically the system whereby the various motors are energized and the various burners and blowers controlled, The

system consists broadly of an electrical circuit for` energizing the various blower motors |1, I I3 and IIB, a fuel `supply system consisting of piping controlled by a magnetically operated master delay relay inserted in the circuit of themaster magnetic valve delays the opening of this valve until the blower motors I|3 have been in operation a predetermined length of time so as to clear the oven of inflammable or explosive gases before the burners can be ignited.

In particular, the electrical system consists of power current supply lines |50 to |52 having a single throw switch |53. This controls the energization of the blower motor energization lines |54, |55 and |56 leading to the blower motors I|3 and I|9 and also to the exhaust fan motor I1. Consequently when the switch |53 is closed, the blower motors I1, ||3 and ||9 start in operation, permitting the blowers to clear the interior of the oven of all explosive gases. Leading from the power lines |54, |55 and |56 are auxiliary power lines |51, |58 and |59 for energizing the air compressor motor |60 which operates the air compressor I 6I. The latter has an intake |62 and a discharge conduit |63 leading by branch lines |64 to electrically controlled proportional mixers |65. The branch lines |64 contain manual air valves |66.

Fuel gas is supplied to the proportional mixers |65 from the gas supply line |61 by way of the magnetically operated valve |68, the gas supply line |69, the branch lines |10, the manual gas valves I1| and the magnetically operated gas valves |12. From the proportional mixers |65 the conduits |13 lead to the burners I6. Associated with each burner I6 is a thermocouple |14 which generates current when it is heated by the burner I6. This current is conveyed through the lines |15 and |16 to the operating coil of the normally closed gas valve |12 to maintain it open while the burners I6 are alight but to permit the gas valves |12 to close when the burners are not lighted. The normally closed magnetic valves |12 are provided with manually operated valve members |11 by which the valves |12 may be manually opened when the burners I6 are ignited.

The electrical circuit (Fig. 11) includes the contactor switches |92, |93 and |94 having operating coils |95, |96 and |91 respectively connected either to the power lines |54 and |56 or to the power lines |51 and |59. The contactor switches I 92, |93 and |94 are normally open, and are closed by the energization of their operating coils |95, |96 and |91 in response to the closing of the switch |53. The latter, when closed, energizes the blower motors I I3 and causes the blowers to operate.

Running from the current line |88 is a line 98 which continues in the line |99 beyond the contactor switch |92. The line |99 is provided with a series of normally-open air-responsive switches 200 which are closed automatically when the blower motors I3 are operating, thereby permitting current to be transmitted to the contactor |93, thence through the line 20| through the contactor |94 to the line 202 leading to the timedelay relay 203, from the opposite pole of which a line 204 leads to the current supply line |81.

Thus, when the blower motors I|3 are operated, the'contactor switches |92, |93 and|94 close and the switches 200 likewise close to permit current to energize the time-delay relay 203.

After the latter has run through its cycle, it ener- Operation In the operation of the machine of this invention, the main and auxiliary driving motors 22 and 23 are energized to cause the conveyor I| to pursue its orbital path through the oven I0 and also to drive the printing press I9 and coating machine 20. The switches |53 are then closed, energizing the blower motors I1, I3 and I I9, and causing air to flow through the oven in a circuitous path opposite the direction travel of the conveyor II. The baiiies |02 cause the air to move up and down between the carriers I2, so that the air follows a zigzag path as indicated by the arrows in Figures 1 and 2.

The operator now closes the switches |9| and |84 to energize the control circuit. The air operated valves 200 then close under the influence of the blast of air from the blowers, thereby closing the circuit to the time-delay relay 203 through the contactor switches |92, |93 and |94, which have been closed since the blower motors II3 were energized by the closing of the switch |53. After a predetermined time, the gas valve I 68 opens after being energized by the time-delay relay at the end of its cycle and fuel gas passes from the conduit |61 into the conduits |69 and |19, Meanwhile, air has been supplied by the compressor |6| to the conduits |63 and |64 leading to the proportional mixers I 65. It is, of course, assumed that the manual valves |66 and I1I have been opened.

The operator now opens the normally closed gas valves |12 by pressing upward 0n the valve members |11, permitting gas to flow from the conduits |10 into the proportional mixer |65. The motors of the latter have been energized through the lines |85 and |86 by the closing of the switches |84, and consequently mixed gas is suppliedto the burners I6 through the conduits |13. The operator lights the burners I6, holding up the valve members |11 manually until the heating of the thermoccuples |14 generates enough current to energize the operating coils of the magnetic gas valves |12, a suicient amount to hold them open. If the temperature rises and falls in the oven, the thermostatic bulbs |19 and the temperature control instruments |80 so regulate the proportional mixers |65 that the ratio of air to gas remains the same while the volume is varied in order to maintain a substantially constant temperature within the oven I0.

In the meantime, the printing machine |9 and coating machine 20 have been imprinting designs on the sheets 20 of tin or other material, and these have been deposited upon the carriers I2 as the conveyor II moves them through the oven. The heated air circulates in a zigzag path through the spaces between the carriers and the sheets, and follows a general direction opposite to the direction of travel of the conveyor II, due to the operation of the exhaust chain 98. As the sheets or plates emerge from the vestibule |0|, they are cooled by the drafts of cool air coming from the cooling fans |20 operated by the motors |I9.

White the carriers I2 move over theauxilary conveyors 68, the latter extend into'fthe'spaces in the bottom edges of the carriers l2,engaging the bottom edges of the sheets 9D; Since the auxiliary conveyors B are moving more rapidlythan the main conveyor chains 63, the bottom edges of the sheets or plates lill are moved ahead of their top edges (Fig. 1G) so that as the carriers I2 swing downwardly around the shaft 62`as an axis, the sheets @il lie flat against the back of each carrier, until they arrive at the withdrawal "conveyors 'E3 and l1. The latter conveyors then convey the sheets to thenextfstagebf operations such as the forming oi"V cans from the sheets.

If at any time the gas supply isaccidentally interrupted, the thermocoupl'es VM1 immediately cease to generate current and the magnetic valves ll automatically close. This cuts off the supply of gas to the burners It which cannot thereafter be lighted until the switches |12 are manually opened as previously described, Meanwhile, the auxiliary driving motor 23 has also been operating but it has failed thus far-to drive the shaft 3l since the automatic body clutch 38 prevents this by the slippage of the clutch members 18 and 83 relatively to each other (Fig. 9).

If now the desired quantity of sheets or plates have been printed and coated and the main driving motor 22 is shut down to halt the machines I9 and 20, the shaft 25 and the pulley or sprocket til immediately come to restl Due to the provision of the automatic jaw clutches 34 and 3Q, however, the auxiliary driving motor 23 now drives the shaft 3l through the jaw clutch 33 while the clutch members of the jaw clutch 34 slip relatively to each other.

While a specilic embodiment of the invention has been described and illustrated, it vwill be understood that various modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

What I claim is:

l. In a heat processing machine, an elongated oven having a downwardly inclined inlet end with a substantially horizontal inlet, a conveyor movable upwardly through said inlet end and through said oven, rack members carried by said conveyor for supporting sheet material on edge while being conveyed through said oven and to extend transversely of said inlet end and partially close said inlet, heating means in said oven, a series of blowers arranged beneath the conveyor in said oven for directing heated air upwardly between said conveyor and the sheet material thereon, one of said blowers being disposed adjacent said inclined inlet end 'to direct a blast of heated air transversely thereacross, and an exhaust fan disposed in one of the walls of said inclined inlet end for removing combustible gases from said Oven.

2. In a heat processing machine, an elongated oven having downwardly inclined inlet and outlet ends with a substantially horizontal inle't, a

conveyor movable through said inlet end and` along said oven with the lower course thereof returning to said inlet end externally of said oven, a series of racks arranged on said conveyor for supporting sheet material on edge during its travel through said oven, said racks being arranged to support the sheet material in a substantially horizontal position during its passage upwardly through said inlet end. to partially close said inlet, heating means located in said oven, a plurality of blowers beneath said conveyor arranged inseries with`their intakes toward said 'oven outlet and with their exhausts toward said voven inlet, said blower exhausts having upwardly directed baille portions disposed between adjacent blowers whereby to move heated air along a vertical zigzag path in a direction opposite to the direction of conveyor travel,- one of said blowers being positioned adjacent said inlet end to directa blast of air thereacross and form an air wall thereatfand an exhaust fan disposed in one of the walls of the inclined inlet end to remove combustible gases fro-m said oven.

"3. In `a heat processing machine, an elongated oven.-having downwardly inclined inlet and outletends with ia substantially horizontal inlet, a `conveyor movable upwardly through said inlet end and through said oven, a series of racks arranged on said conveyor for supporting sheet material onv edge during its passage through said oven and in a substantially horizontal position during its passage through said inlet, heating means in said oven, a plurality of blowers beneath said conveyor arranged in spaced apart relation for directing blasts of heated air upwardly through said conveyor and between said sheets of material, delector means mounted 0n the roof of the oven for directing said heated air in a downward direction toward the intake of an adjacent blower, means for driving said blowers, means for driving said conveyor, and an exhaust fan disposed in one of the walls of the inclined inlet end for removing combustible gases from said oven.

4. In a heat processing machine, an elongated oven having downwardly inclined inlet and outlet ends with a substantially horizontal inlet, a conveyor movable upwardly through said inlet end and through said oven, a series of racks arranged on said conveyor for supporting sheet material on edge during its passage through said oven and in a substantially horizontal position during its passage through said inlet, heating means in said oven, a plurality of blowers beneath said conveyor arranged in spaced relation, for directing blasts of heated air ,upwardly through said conveyor and between said sheets of material, deflector means mounted on the roof of the oven for directing said heated air in a downward direction toward the intake of an adjacent blower, means for driving said blowers, means for driving said conveyor, and an exhaust fan disposed in one of the walls of the inclined inlet end for removing combustible gases from said oven, said blowers being arranged t0 create a forced draft from one end of the oven to the other in a direction opposite to the direction of conveyor movement.

5. In a heat processing machine, an elongated oven having-downwardly inclined inlet and outlet ends with a substantially horizontal inlet, a conveyor movable upwardly through said inlet end and through said oven, a series of racks arranged on said conveyor for supporting sheet material on edge during its passage through said oven and in a substantially horizontal position during its passage through said inlet, heating means in said oven, a plurality of blowers beneath said conveyor arranged in spaced apart relation for directing blasts of heated air upwardly through said conveyor and between said sheets of material, deflector means mounted on the roof of the oven for directing said heated air in a downward direction toward the intake of an adjacent blower, means for driving said blowers, means for driving said conveyor, and an exhaust fan l l disposed in one of the' walls of the inclined inlet end for removing combustible gases from said oven, and fan means mounted in close proximity to said outlet for directing a blast of cool air upwardly between said sheets of material as they pass from said oven.

6. In a heat processing machine, an elongated oven having downwardly inclined inlet and outlet ends with a substantially horizontal inlet, a conveyor movable upwardly through said inlet end and through said oven, a series of racks arranged on said conveyor for supporting sheet material on edge during its passage through said oven and in a substantially horizontal position during its passage through said inlet, heating means in said oven, a plurality of blowers beneath said conveyor arranged in spaced apart relation for dit 12 recting blasts of heated air upwardly through said conveyor and between said sheets of material, deflector means mounted on the roof of the oven for directing said heated air in a downward direction toward the intake of an adjacent blower, means for driving said blowers, means for driving said conveyor, an exhaust fan disposed in one of the walls of the inclined inlet end for removing combustible gases from said oven, said blowers being arranged to create a, forced draft from one end of the oven to the other in a direction opposite to the direction of conveyor movement, and fan means mounted in close proximity to said outlet for directing a blast of cool air upwardly between said sheets of material as they pass from said oven.

VERNIE A. FOX.