US1748465A - Heating apparatus - Google Patents

Description

Feb. 25, 1930. SUMMEY 1,748,465

HEATING APPARATUS Original Filed May 31, 1923 4 Sheets-Sheet l I m a:

IIVI/EIVTOR TTORNEYS Feb. 25, 1930. D. L. SUMMEY 1,748,455

HEATING APPARATUS Original Filed May '31, 1923 4 Sheets-Sheet 3 //v l/E/j/TOR ATTORNEY) I 0. mm

Patented Feb. 25, 1930 PATENT? OFFICE DAVDL. SUMMEY, OF WATERBURY, GONNECTICUT HEATING APPARATUS Original application filed May 31, 1923,

This invention relates to heating apparatus and more .particularly to annealing 'furnaces.

This application is a division from an application filed May 31, 1923, Serial No. 642,411.

It is an object of the invention to provide an eflicient electric heating furnace that is economical as to heat consumption and labor.

It is a further object of the invention to provide such a furnace in which the articles, such as metal coils, may be heated inductively.

With these general objects in view the invention consists in the features, combinations, details of construction and arrangements of parts which will first be described in connection with the accompanying drawings and then more particularly pointed out.

In the drawings Figure 1 is a View, partly in longitudinal section and partly diagrammatic, of a heating apparatus constructed in accordance with the invention;

Figure 2 is a view, partly in longitudinal section and partly diagrammatic, of a heating apparatus in which the coils are heated by resistors;

Figure 3 is a longitudinal vertical sectional view of the heating chamber shown in Fig. 2;

Figure 4 is a view of the same in side elevation;

Figure 5 is a view of part of the apparatus of Fig. 1 in vertical longitudinal section;

Figure 6 is a detail view showing part of the conveyor chain and pulley in side elevation; and, 2

Figure 7 is a plan view of part of the chain Referring to the drawings, the apparatus shown in Figs. 1 and 5 comprises a long furnace chamber 21 enclosed by a housing 22 of brick and fire brick or other suitable material. There is provided atransformer core and primary coil within the housing, and means for causing relative movement between the transformer elements and the article to be heated to place the latter in inductive relation with the former. Although capable of various constructions, as here shown as an example, communicating with chamber 21, at

Serial 1 642,4,11. Divided and this application filed much as, 1927. Serial No. name.

wound around the central leg of the core.

The primary coil is connected with any suitable current, not shown. Located in the heating chamber 23 below the transformer elements 1s a movable table 29. This table is mounted on a rod or plunger 30, connected to the piston 31 of a fluid pressure unit later described, which moves the table toward and away from the transformer elements. When the plunger 30 is at the far end of its stroke, 1. e. ust beyond the full line position of Fig. 1, the table makes contact with the legs of the core and becomes the fourth leg thereof, the supported coil of material being between the primary coil and the legs. Suitable current being supplied to the primary coil, the

coil of material 10 acts as a secondary and the metal is heated by the induced currents set up therein. The primary coil and the core may be protected by suitable insulation from the heat generated in the coil of material and may be air cooled if desired.

In connection with relative movement of the transformer and article, there is provided means for feeding the articles to be heated onto the table and for removing them therefrom. This may be accomplished, for example, by an endless conveyor capacitated toadvance articles on one strand and remove them on the other strand, the articles being pushed from one strand onto the table and from the table onto the other strand. In the embodiment here shown as an example, running endwise of the furnace chamber 21 is an end ess conveyor chain made up of flat, skeleton links 35 which are functionally reversible. That is, coils of metal or other articles may be carried on either face of the chain. Each link has, at one side, two double lugs 36 and the other side two single lugs 37. The links being assembled, they are connected into a chain by pins 38 passing through suit-- able holes in the overlapping lugs. The chain runs on tracks 39 and over pulleys 40, 41 on shafts 42, 43. Shaft 43 carries, outside As ap in Fig. the chain does double duty. RI?

the-chamber, a gear wheel 4-1 to which' war for dri any suitab e manner. The conveyor may be formed of nickel chromium allov.

the top strand being su lied with mgt al coils at the fab end of e as later described, it carries them toward the heating end, where the are succemively transferred to the table 29 y pusher 27. The bottom strand meanwhile, is ing heated coils, loaded thereon as later scribed, back toward the far end of the furnace chamber. With this arangement theincoming cold coils receive some pre-heatmg from the passing heated'coils. This gives an econom in eat output and, moreover, with a dou le duty chain the dead load is reduced to'a To transfer coils from the top strand of the conveyor to the table, as here shown as an gamplle, sgldalfilfi a thin ble 26 locfited in esi ew o ousing22,opposite eating chamber .23, is a pusher 27 connected to the piston 28 of a fluid premure unit later described. At the time of transfer table 29 is in the dotted line position indicated at 29' of Fig. 1, that is, flush with the upper strand of the conveyor. Advance movement of the pusher 27 pushes a coil from the conveyor'onto the table. The pusher is then withdrawn and the table elevated to heating position. After heating, the table is withdrawn by operation of piston 31 as later described, to the broken line position indicated at 29' in Fig. .1. In this position it is flu'shwith the bottom strand of the conveyor. Opposite the sup rted article, in this 'tion, is a secon transfer lunger 127 shdable in a thimble 126 in the ihrnacewallandconnectedwitht e iston 128 of a fluid ressure unit later escribed. When the tab e reaches discharge 'tion transfer I r 127 is advanced an pushes the hea coi from the table onto the bottom strand of the conve or.

There is provid means for feeding the articles to be heated, e. coils, to the conve or and for dischar 'ng t em therefrom, an in structures embos yi the invention to what is now considered e best advantage, the feeding and dischargigg matically controlled. plished, for example, b feeding and discharging means such as' own in connection with the type of apparatus illustrawd in Figs. 2-4. In the type therein shown the furnace chamber is heated by electric 51 and contains four duplicate conveyors like the conveyor above described. Considering, for the purpose of the present description, the conveyor unit designated 52, at one end of the furnace (the left end as viewed in Figs. 2-4) is an openin 53 having a platform 54 extending inwar y to the to strand of the conveyor chain and outwardly to a is may be accomthe conveyor may be app ed in.

pushed therefrom across means are autogreases supply conveyor 55 ru the inside conveyor. The artic es to be beated, e. g., coils 10, are laced on the su ply conveyor in any sui le manner an are platform '54, onto the conveyor chain 52. This is accomplish 'asshown, by a push rod 56, having a can end to embrace a coil, connected with the piston 57 ofafluid pressure unit. This unit compnses' agnliflger 58, in which M f 517 operates. into opposite 9 cy inder 58are pipes 59, 60 connected b a 4-way valve 61 with an exhaust pipe 62 and a supply pipe 63. Pipe 63 leads to any suitablesource of fluid pressure, e. g., compressed air, not shown. alve 61 being operated, as later described, to connect pipe 59 with supply pipe 63 and pipe 60 with exhaust, the piston is op- .tocausepushrod56topushacoil from a sulp ply conveyor 55 onto conveyor chain 52 1g. 2). Reversal of the valve connects pipe 60 with the supply and pipe 59 with exhaust and the piston reverses to withdraw thepushrod.

Intheembodimentillufiratedfibef' movementofpushrod56isefl'ectedat n J- lntervals synchronous with the conveyor movement. To this end, as here shown as an example, on the shaft 131 that drives the conveyor pulleys is a wheel 132 having a plurality of notches 133. Ridifi on the penph any of this wheel is a pi'vo y mounted detent 134 which drops'into the notches as the wheel rotates. The notches are so that one is resented to the detent each time t isdesi tofeedacoiltothefurnaceconveyor. which is mounted the contact member of a relay 136 located in a shunt across a main line 137 in which shunt is connected one winding .of a reversely wound-solenoid 138. The core connected by a lever 139 v of this solenoid is with the valve of fluid pressure unit 58. When detent 134 drops into a notch, relay 136 is closed. Solenoid 138 is thus actuated to operate the valves of units 58 and cause pusher 56 to push chain.

There is provided erated door for the openin 53. As here shown. as an example, a iding door 68, notched or slotted to accommodate the platfornaand hooked rod, is capacitated to close opening 53. The door is operated by a lever 69 connected by a link with the piston rod 71 of a flulgegrassure unit 72 like unit 58 above descri The valve of unit 72 is connected by a lever 141 with the core of a reversely' wound solenoid 140. One windmg of th1s solenoid is in parallel with the shunt contaimng the winding of solenoid 188 above referred to. When, therefore, rela 136 is closed by detent 134, energized to cause door 68 to o n f -t passage of the pushed coil. pe or he an automatically op- Thedetentcarriesanarmon a coil onto the conveyor 7 III solenoid is conveyor or the coils carried thereby.

To reverse the parts, as here shown as an example, the piston of unit 58 has a rear extension 142 carrying a trip arm 143 located to trip a spring-pressed lever 144 as the pusher 56 reaches the end of its feeding stroke. This lever is connected with the contact member of a relay 145 located in a shunt across the main line 137, in which shunt is connected the second or reverse winding of solenoid 138. In parallel with this shunt is a loop including the second or reverse winding of solenoid 140. When relay 145 is closed by the advance. of pusher 56, the cores of solenoids 138 and 140 are reversed, thus reversing the valves of units 58, 72 and thereby causing withdrawal of pusher 56 and closing of .door 68.

It is to be understood that the furnace 22 is provided, near the end opposite the heating chamber, with an opening like opening 53 and that a feeding unit such as that just described is provided for feeding coils to the conveyor chain 35.

In the furnace shown in Figs. 2-4 coils are fed to the left end of the top strand of chain 52 and the right end of the bottom strand and removed vice versa. In the induction furnace of Figs. 1 and 5 there is only one feed and one discharge.

In connection with the discharge mechanism, the unit shown at the right of Figs. 2 and 4 will first be described. Extending through an opening 146 in the furnace wall is a hooked rod 147, the hooked end being arranged to receive a coil as the conveyor advances. This rod is connected with the piston of a fluid pressure unit 148 like unit 58 above described. The rod normally extends into the furnace. When a coil is received by the hook and the rod is withdrawny it pulls the coil outof the furnace across a platform 54 onto a discharge conveyor 149.

The removal of a coil from the conveyor is controlled by the movement of either lie s here shown as an example, in line with the conveyor chain at the discharge end, is a contact plunger 150 slidable in the wall of the furnace and normally held by a spring in a position to be engaged by a coil as the latter is moved into the embrace of the hooked discharging rod. The other end of contact plunger 150 carries the contact member of a relay 151 located in a shunt across the-main line 137, in which shunt is connected one winding of a reversely wound solenoid 152. The core of this solenoid is connected with the valve of fluid pressure unit 148 that operates the hooked rod. When a coil moves into the embrace of the hooked rod 1t actuates plunger 150 to close relay 151 thus causing solenoid 152 to operate the valve to cause withdrawal of the hooked rod, thereby discharging a coil. To return the hooked rod to normal position, as here shown as an example, carried by the hooked rod is trip arm 154 arranged to trip a spring-pressed lever 155 when the hooked rod has reached the end ofits withdrawing stroke. This lever is connected with the contact member of a relay 156 located in a shunt across the main line 137, in which shunt is connected the second or reverse winding of solenoid 152. When relay 156 is closed by trip 154, solenoid 152 is reversed thereby reversing the fluid pressure unit and returning the hooked rod to normal position.

A door for the discharge opening is provided. As here shown as an example, the opening 146 is closed by a sliding door 160 like door 68. This door is operated by a lever 161 connected with the piston of a fluid pressure unit 162 like those described. The valve of this unit is connected with the core of a reversely wound solenoid 163. One winding of this solenoid is connected in a loop paralleling the shunt of .relay 151, the

other winding in a loop paralleling the shunt of relay 156. When relay 151 is closed, solenoid 163 operates the valve of fluid pressure unit 162 to open the door and when relay 156 is closed upon return of the hooked rod. solenoid 163 is reversed to reverse unit 162 and close the door.

The furnace 22 of Figs. 1 and 5 is provided with a discharge mechanism like that just described. The furnace 22 may have, opposite the infeed opening, an outfeed opening like opening 146. In such case the discharge unit described may be duplicated. Or the discharge may be effected at the same side as the in-feed, through a common opening, in the manner illustrated in Figs. 3 and 4. As there shown, below the in-feed pusher 56 is a hooked rod similar to rod 147 and a discharge conveyor 65 similar to conveyor 149 except that it runs in a different direction. Such an arrangement may be used in the furnace of Figs. 1 and 5, with the rod operating and control means described.

The conveyors 55, 149, 65 are shown diagrammatically as short endless belts. It will be understood, however, that they may be extended to carry the coils from or to any' point desired. Instead of a discharge conveyor, there may be used an elevator or the like to carry the removed coils to aquenching pit.

As will be apparent from the drawings (Fig. 1), piston 28 forms part of a fluid pressure unit 75 like unit 58 above described. That is, pressure fluidis admitted alternately to either end of the cylinder, the other end exhausting, by a 4-way valve. Pistons 31 and 128 form part of similar units 76, 77.

While the valves of fluid pressure units 75, 76, 77 may be operated in any suitable manner, in structures embodying the invention to what is now considered the best advantage, provision is made for an automatic ontheendofasp is-connected by a ever 8.0 with the core of a doubly or reversely wound solenoid 81. One winding of this solenoid is connected inshuntacrossamainline 82,thisshunt eluding a relay 83. The mam line wire 18 sh connected with a suitable source, not-shown. The contactmember of relay 88 1s camed ring-p contact lunger =84 .slidable in the end of the housing (li ig. 5). normal ptclistaolzhthg end of the contact unger 18 in pa 9 a coil as it is move d by the conveyor chain into position opposite table 29. When a coil -m a manner to advance is connected wit 'reachessuch position it actuates plunger 84 to close relay 83. This causes solenoid 81 to operate the valve of fluid pressure umt iston 28 and cause pusher 27 to push the coi from the conveyor onto waiting table 29. a

Withdrawal of the pusher is controlled by its own 'tion. To this end as here shown as an $18, piston 28 has a rear extension 86 ca a trip arm 87 positioned to trip, as the piston reaches the end of its adv an stroke,-a springremed lever 88. This lever the contact member of a relay 89 located in a shunt acmesthe main line 82, in which shunt is connected the second winding of solenoid 81. When relay 89 is closed b trip arm 87 the valve of nmt 75 is reversed and usher 27 is withdrawn.

At the ri in the cycle of operation when a co is being transferred to table 29,

I fluid ressure unit 76, as later referred to,

is ten 'ng to elevatethe table,-but the parts are held against movement beyond position 29- until a coil is received. To this end, as here shown a an example, piston 31 of table unit 76 carries a rear extension 90 on which is an arm 91. This arm is adapted to beengaged b a sliding stop 92, movable into and out of e path of the arm. Stop 92 is connected' by a lever 97 with the core of a reversely wound solenoid 96. Assuming the stop to be advanced, holdi the table unit in position 29 the stop is re eased upon receipt of a coil on the table and the withdrawalof the pusher 27. To th1s end, on extension 86 of in-feed unit 75 1s a trip arm 93 adapted to trip momentanly, a springpressed lever 94 as the pusher approaches withdrawn position. Lever 94 cames the contact member of a relay 95 located m a shunt across the main line, in which shunt is connected one winding of solenoid 96.

When relay 95 is momentarily closed, upon withdrawal of pusher 27, the operation of solenoid 96 causes withdrawal of stop 92. Stop arm 91 being thereby released, unit 76 is free to completeits advance stroke, thereby elevating table 29 to coil-heating position.

.controlled by the V 1,740,4ea

Following the momentary actuation of relay 95 by tribpgarm 93, the solenoid and stop parts, as will apparent, are held in position by inertia un the solenoid is reversely ener- Provision is made for loweringthe table to remove the coil from heat position after a given time interval. To i is end, as here own as an example, mounted on shaft 43 is a wheel 98 having a pluralit of spaced notches 99. Riding on the periphery c this wheel is a spring-p pivoted detent 100 which carries the con ct member of a relay 101. This relay is located in a shuntacrosa the main line 82, in which shunt is connected one winding of a versely wound solenoid 102. The cone of t by a lever 103 with the valve of fluid pressure unit 76. When detent 100 drops into a notch 99, relay 101 is closed and solenoid 102 operates its valve in a manner to cause withdrawal of piston 31 and lowering of table 29 to position 29'. This places the heated coil op site the lower strand of the conveyor a: transfer thereto by7pusher 127.

Discharge unit operating usher 127 is extension 90 of table unit 76 is a trip arm 105 arranged to trip momentarily a p lever 106 as the piston of 3 2gg llloaches the end of its withdrawing stroke. is lever 106 carries the contact member of a relay 107 that is located in a shunt acres the main line, in which shunt is connected one winding of a reversely wound solenoid 108. 'lhe core of this solenoid is connected by a lever 109,with the valve of dischar unit 77. When relay. 107 is momentarif; closed by trip arm 105 the valve of unit 77 is operated by solenoid 108 to cause pusher 127 to be-advanced, thereby dischar the heated coil from table 29 onto the ower strand of the conveyor chain. As in the case of stop 92. the valve of unit 77 and the core of solenoid 108, following momentary actuation of relay1107, are held in position by inertia until t e solenoid is reversely actuated. The withdrawal of pusher 127 is controlled by its own advance movement. To this end. the piston of unit 77 carries a rear extension 109' on which is a trip arm 110 arranged to trip a spring-pressed ever 111 as piston 128 completes its pushing stroke. This lever 111 carries the contact member of a relay 112 that is located in a shunt across the main line in which shunt is connected the reverse winding of solenoid 108. When relay 112 is closed by tri arm 110, the valve of unit 77 is reveised by the solenoid and pusher 127 is withdrawn. v

The elevation of table 29 to receiving ition is controlled by the withdrawal 0 discharge pusher 127. To this end, as here shown as an example, extension 109 of dis is solenoid is connected position of t e table unit. cmg To this end, as here shown as an example, on-

arranged to trip, as pusher 127 reaches with-- drawn position, a s ring-pressed lever 114. This lever carries t econtact member of a relay 115 that is located in a shunt across the main line, in which shunt is connected the reverse winding of solenoid 102. When relay 115 is closed by trip arm 113, as the discharge pusher is withdrawn, the valve of unit 76 is reversed by solenoid Y102 and the table 29 1s caused to be raised. While unit 76 tends to raise the table to its extreme position stop 92, meanwhile, has been returned to stopping position. To this end, as here shown as an example, the reverse winding of solenoid 96 is connected in a loop in arallel with the shunt controlled by relay 10 When this relay is closed, as above described, bythe withdrawing of piston 31, stop 92 is returned to stoping position by solenoid 96, being held there By inertia. Consequently, by reversal of the valve of table unit 76 upon withdrawal of pusher 127, table 29 is elevated only to position 29, arm 91 engaging stop 92 to maintam this position until the stop is agam withdrawn as above described. It will be understood that the valve of unit 76 remains in 'th1s position to cause continued advance of the table plunger upon removal of the stop, as above described. I

In reviewing the operation of the apparatus described, it is assumed that the feeding and dischargin means of Figs. 2 and 4 are appliedto the furnace of Figs. 1 and 5. As the conveyor chain advances, rotation of ratchet 132 causes relay 136 to close, thereby energizing solenoids 140 and 138. This causes fluid pressure unit 72 to open door 68 and unit 58 to advance push rod 56, thereby pushing a coil from supply conveyor across platform 54 to the upper strand of conveyor chain 35.

., As push rod 56 reaches the end of its advance stroke, trip arm 143 closes relay 145 to energize the reverse windings of solenoids 140 and 138. This reverses the valves of pressure units 72 and 58 and closes the door and withdraws the push rod.

The conveyor chain carries the coil through chamber 21 toward chamber 23. At the time it comes opposite the latter, table 29 is in the dotted line position 29 of Fig. 1, i. e. level with the upper strand of the chain. At this time the valve of fluid pressure unit 76 is set J to advance the table but the parts are held by stop 92. As the coil comes opposite the chamber 23 (Fig. 5) it strikes the end of detector plunger 84 which is displaced to close relay 83. This energizes one winding of solenoid 81 to cause fluid pressure unit 75 to advance the infeed pusher 27 which pushes the coil from the conve or onto table 29. As pusher 27 reaches t e end of its advance stroke, trip arm 87 closes relay 89 and energizes the reverse winding of solenoid 81 to reverse fluid pressure unit 75 and withdraw pusher 27. As the pusher returns to withdrawn position trip arm 93 momentarily closes relay 95 to energize solenoid 96. This causes withdrawal of stop 92, thereby permitting further movement of table 29 to carry the coil into inductive relation with the transformer elements. The coil now functions as the secondary of the transformer and is heated by the induced currents set up in the metal of the coil.

The duration of the heating period is timed by ratchet 98. As this latter rotates, detent 100 drops into a notch 99 and relay 101 is closed to energize the reverse windin of solenoid 102, thereby causing reversal 0 unit 76 which withdraws the table and its coil from heating position to a position opposite the bottom strand of the conveyor chain, i. e. position 29".

As the platform reaches this position, trip arm 105 momentarily closes relay 107, thus energizing the reverse winding of solenoid 96 to reset stop 92 and a winding of solenoid 108 to cause unit 77 to advance the out-feed pusher 127. The latter pushes the heated coil mm the platform onto the lower strand of the conveyor chain which carries it back toward the far end of the furnace. As pusher 127 reaches the end of its advance stroke trip arm 110 closes relay 112 to energize the re verse winding of solenoid 108, whereby unit 7 7 is reversed and pusher 127 withdrawn. As the latter reaches the end of its back stroke, trip arm 113 closes relay 115 to energize the reverse winding of solenoid 102, whereb unit 76 again starts the platform forwar the stroke being interrupted by stop arm 91 engaging stop 92. The parts are now in initial position for the next coil.

As the conveyor 52 carries the heated coil back to the far end of the furnace the coil moves into the embrace of hooked rod 147 and detector plunger 150 (Fig. 2) is actuated by the coil to close relay 151. Th1s energizes solenoid 163 to cause unit 162 to open door 160 and also energizes solenoid 152 to cause unit 148 to withdraw rod 147, whereby the coil'is pulled out of the furnace chamber onto conveyor belt 149. As the hooked rod reaches the end of this withdrawing stroke, trip arm 154 closes relay 156. This energizes the reverse winding of solenoid 152 to reverse unit 148 and return the hooked rod and the reverse winding of solenoid 163 to reverse unit 162 and close the door. i

- It will be apparent that the various relays are opened, upon release of the closing forces, by their respective springs.

What I claim is:

1. In a heating apparatus, and in combination, a heating chamber, a conveyor run ning past said chamber, a transformer core and primary coil within the chamber, means for moving a coil of material from said con.

, heated coil of material onto the second strandond chambe tion, a heating c causing relative movement between the coil of material and the transformer elements to place the coil of material in inductive relation with the transformer elements, and means for moving the heated coil of material onto the conve or.

2. n a heating apparatus, and in'combination, a heating chamber, a transformer'core and primarycoil within said chamber, a'second chamber communicating with said heating chamber, an endless conveyor in said secr running past the heatin chamber, means for moving a coil of material from one strand of said conveyor into 'theheating chamber, means for causing relative movement between said coil of material and the transformer elements to place the coil of mab terial in inductive relation with the transformer elements, and means for moving the of said conveyor.

8. In a heating apparatus, and in combination, a heating chamber, a transformer core and primary coll within said chamber a second chamber communicating with said heating chamber, 'an endless conveyor in said second chamber movin past said heating chamber, a movable plat orm, a pusher for ushing a coil of material from one strand 0 said conveyor onto said platform, platform moving means for causing the coil of material to be placed in inductive relation with said transformer element and removed therefrom, and a pusher for pushin a coil of material from said platform onto t e second strand of said conveyor.

4. In a heatin apparatus, and in combinaamber, a transformer core and primary coil within said chamber, asecond chamber communicating with the heating chamber, an endless conveyor in said second chamber moving past the heating chamber, a movable platform, a pusher for pushing a coil of material from one strand of the conveyor onto said platform, platform moving means for causing the coil of material to be laced in inductive relation with said transiormer element and removed therefrom, a pusher for pushing 'a coil of material from said platform onto the second strand of said conveyor, and automatic controls for said pushers and platform moving means.

5. In a heating apparatus, and in combination,a heating chamber, a transformer core and primary coil within said chamber, a second chamber communicating with the heat' chamber, an endless conveyor in said secon cause the coil of material chamber movi past the heating chamber, a movable plat orm, transfer means including a fluid pressure unit for moving a coil of material from one strand of the conveyor onto said platform, means including 'a fluid pressure unit for moving the platform to tobeplacedin'im' veyor moving past .ing the coil ductive relation with said transformer element and removed therefrom, transfer means including a fluid pressure unit for moving the coil from said platform onto the second strand of said conveyor, solenoids for operating the valve mechanism of said fluid ressure units, and lays for actuating said solenoids.

6. In a heating apparatus, and in combination, a heating chamber, a transformer core and primary coil within said chamber, a consaid heating chamber, a platform movable toward and away from said transformer elements, transfer means for transferring a coil of material from the conveyor onto said platform, means for moving the platform to cause the coil of material to placed in inductive relation with said transformer elements and removed therefrom discharge means for discharging the coil from said platform onto the conveyor meanscontrolled by the movement of sai transfer means for automatically controlling the advancing movement of said platform, and means controlled by the reverse movement of said platform for automatically controlling the operation of said discharge pusher. 7. In a heatin apparatus, and in combination, a heating fiiamber, a transformer core and primary coil within said chamber, a conveyor moving past said heating chamber, a platform movable toward and away from said transformer elements, transfer means for transferring a coil of material from the conveyor onto said platform, means for moving the platform to cause the coil of material to be placed in inductive relation with said transformer elements and removed theredischarge means for discharging the coil'from said platform onto the conveyor, means controlled by the movement of said transfer means for automatically controlling the advancing movement of said platform, means automatically operated after the platform has remained in advanced position a predetermined time interval for causing reverse movement of the platform, and means controlled by the reverse movement of said platform for automatically controlling the operation of said discharge pusher.

8. In a heating apparatus, and in combination, a heating chamber, a transformer core and primary coil within said chamber, an endless'conveyor moving past said heating chamber, a platform movable toward and away from said transformer elements, a transfer pusher for transferring a coil of material from one strand'o'f the conveyor onto said platform, a discharge pusher for pushfrom said platform onto the other strand of said conveyor, fluid pressure unite for operating said pushers and said platform. and means for automatically effecting the opautomatically controlle re-' eration of said fluid pressure units in proper sequence.

9. In a heating apparatus, and in combination, a heating chamber, a transformer core and primary coil within said chamber, an endless conveyor moving past said heating chamber, a platform movable toward and away from said transformer elements, means tending to advance said platform toward the transformer elements, stop means for holding the platform in a position substantially flush with one strand of the'conveyor, a transfer pusher for transferring a coil of material from the conveyor to the platform, and means controlled by the movement of said pusher for automatically rendering said stop means ineffective, whereby said platform is moved into coil-heating position.

10. In a heating apparatus, and in combination, a heating chamber, a transformer core and primary coil within said chamber, a conveyor moving past said chamber, a platform for receiving a coil of material and placing it in inductive relation with said heating elements, a transfer pusher for transferring a coil of material from the conveyor to said platform, and means controlled, by the posi-' tion ofan approaching coil on said conveyor for automatically advancing said pusher upon the arrival of a coil opposite said heating chamber.

11. In a heating apparatus, and in combination, a heating chamber, a transformer core and primary coil within said chamber, a conveyor moving past said chamber, a platform movable toward and away from said transformer elements, a transfer pusher for transferring a coil of material from the conveyor to said platform, a discharge pusher for discharging the coil from the platform to said conveyor, fluid pressure units for actuating said platform and said pushers, reversely wound solenoids connected to the valves of said fluid pressure units, circuits for said windings including relays, and relay-actuat 7 ing devices for effecting automatic operation my hand.

of said fluid pressure units.

In testimony whereof, I have hereunto set DAVID L. SUMMEY,

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