US2565957A - Divided inductor with surrounding quenching device - Google Patents

Description

J. A. EVANS Aug. 28, 1951 DIVIDED INDUCTOR WITH SURROUNDING QUENCHING DEVICE 2 Sheets-Sheet 1 Filed D520. 11, 1948 M. m PM a.

W. 7 v w W Aug. 28, 1951 Filed Dec.

J. A. EVANS DIVIDED INDUCTOR WITH SURROUNDING QUENCHING DEVICE 2 Sheeis-Sheet 2 Patented Aug 28, 1951 UNITED STATES PATENT OFFICE DIVIDED INDUOTOR WITH SURROUNDING QUENCHING DEVICE John A. vans, Milwaukee, ass ig'fic'r as Ame Chalmers Manufacturing Company, Milwaukee, Wis., a corporation or Delaware Application December 11, 1948, Serial No. 64,862

4 clams. (01. 266-4) This invention relates generally to impr6ve ments in means for inductively heating and for fluid quenching a workpiece and particularly to improved means for applying a quenching fluid through the work coil of an induction heater. And this invention is especially useful in connection with work coils having but one inductive turn or loop.

In the mass manufacture of machinery, it is common practice to machine many of the component parts from relatively soft stock; and then in a final operation to prepare these parts for surface hardening by feeding them into a work coil of a high-frequency induction heater. In surface hardening by induction heating followed by quenching, the steel is quickly raised to a bright-red heat by the induction heater, and then rapidly cooled by the quenching fluid. As a consequence, a relatively thin shell of hardened metal is produced surrounding the steel workpiece. The fact that the shell is thin is due to the skin effect always associated with the flow of high-frequency currents, and to the fact that the heat is applied so rapidly that the temperature can readily be confined to the surface layers.

In order to obtain the best grain structure for hardness, the temperature from which the work'- piece is rapidly cooled should be above the critical temperature of the steel. Consequently it is important to quench'the workpiece immediately following the heating operation. Otherwise the temperature of the heated shell may fall below the critical temperature before the quenching starts. Furthermore, any material flow of heat from the shell to the interior of the workpiece affects the final dimensions of the hardened surface layer. It is therefore the practice, when an induction heater is employed in assembly line manufacture, to feed into the work coil, one at a time, a series of workpieces for heating, and then at the end of the heating cycle, to rapidly quench each piece in place before removing it from the coil.

An examination of the prior art reveals that with some types of multiturn work coils, the quenching liquid is introduced between adjacent turns of the coil, and with some types of singleturn work coils the quenching liquid is introduced from either side of the coil against the workpiece. In another type of single-turn 0011, the quenching liquid is circulated through the coil, which is formed of copper tubing, and sprayed against the workpiece by means of a plurality of holes annularly spaced around the inside of the coil turn.

The disadvantages inherent in the prior 'art meansfor inductively heating and for Quenching a workpiece are many, particularly with respect to ingle-turn 6611s. in the type of s1n'g1e turn coil first menticnedyinwhich the quenchi g liquid is directe d against the workpiece from either side of s arse quenching is frequently localized and uneven, particularly if'the coil is formedfroin a 'flat' eon'dii'ctor having a width commensurate with the length of turn, since it is apparent that the liquid must first absorb heat frbrn the end Zones or the workpiece before reachinga'nd absorbing heat from the central zone. If the l i'q'uid has a relatively long way to traveland'changesto 'a gaseous state" before reaching the central z ne of the workpiece, the quenching aetien in'tha't region is substantially nil. As a consequence, the workpiece may end up with a heat-treated 'zone not only of variable hardness but also of variable depth of" hardness. A

In the second type of single-turn can mentioned above, in which the quenching liquid circulates through the hollow tubing 6f the boil, the

duration of the applied heating cycle is definitely tages the periodic application of quenching liquid t a Wk 2 the??? freewar at the endof each heating cycle may be in the neighe c amo 1 p 5 a wil re lif an 1 11- itial flash of vapor at the beginning of each quenching cycle, providing the quenching liquid has atoning point'belew"thejstated values. A 'time lag is thus introduced which begins at the end of the heating cycle and extends up to the instant when the quenching liquid portion still in the liiuid state actually "impinges on the workpiece In this te'rval "of time the temperature of'the workpiece can fall below its critical temperature. As previously explained, the

we in c l fi llf enpr' iife i i f t 'e adversely a ects t e fi ia1:. r' 1 5 .16 n? degree of hardness achieved is also a function "'of th e cooling'rate itis iinportant that the workpiece be quenched with a 'cold liquid rather "than with a liquid that has *pr'e'v imny'been heated by passage through a hotwork'ceil. I

I'lurthermb're, the periodic jappuea'ucin of fluid 'ad ers'ely affects the work coil, since the flashing of the fluid to-vans pauses the formation of scale in the interior oft'he" ccil, resulting in a decrease in the teenag annel cross section as Well as in the cooling 'efiiciency.

3 Still another drawback only too apparent is the inability of the coil in a brazing operation to dissipate suflicient'heat when the coil is required to' heat a workpiece having a resistivity comparable to that of the coil. If the workpiece is sufficiently heated during the heating cycle,

the coil will be overheated, with arapid formation of scale on the surfaces of the coil, both inside and out. Repeated heating. operations under such conditions, if frequent enough, will eventually destroy the coil.

A satisfactory work coil for an induction heater embodies an inductor that will handle the maximum power output of the induction heater and still have .as small a cross section as possible. With alloy steels containing large amounts of nickel, manganese, chromium and the like, the power requirements are likely to be high. Therefore, the inductor must be of small cross section to concentrate the power as much as possible. Furthermore, the inductor should be provided with a conduit capable of continuously circulating the requisite amounts of cooling fluid.

It is therefore an object of the invention to provide an improved heating inductor in which the aforementioned disadvantages of the prior art are obviated, and in which the aforementioned advantages are achieved.

The present invention proposes to cool the single-turn work coil of an induction heater by a continuous flow of cooling fluid and to apply the quenching fluid against the workpiece through the single-turn coil independently of the flow of cooling fluid.

Another object of the present invention is to provide an improved heating inductor in which the cooling fluid is circulated during energization of the inductor as well as during the application of quenching fluid to the workpiece.

Another object of the invention is to provide an improved heating inductor in which quenching fluid is directed through a turn of the inductor against the workpiece.

Another object of the invention is to provide an improved heating inductor in which quenching fluid is introduced through a turn of the inductor without the fluid impinging on the inductor prior to striking the workpiece.

Another object of the invention is to provide an improved heating inductor in which quenching fluid may be directed against the workpiece from substantially all sides of the inductor and through a turn of the inductor.

Another object of the invention is to provide an improved heating inductor which maybe divided to insert a workpiece without interrupting the flow of cooling fluid.

Another object of the invention is to provide an improved heating inductor in which the source of quenching fluid is insulated from the inductor.

Another object of the invention is to provide an improved heating inductor in which the quenching and cooling fluids do not mingle.

Another object of the invention is to provide an improved heating inductor in which the quenching fluid is thermally insulated from heat generated by the inductor.

The novel features of this invention and how the objects are obtained will appear from the specification and the accompanying drawings showing several embodiments of the invention and forming part of this specification and all the novel features are intended to be pointed out in the claims.

. away In the drawings:

Fig. 1 is a plan view of an inductor and quenching jacketillustrating one embodiment of the invention in which part of the jacket is broken to disclose the internal structure thereof; Fig. 2 is a section taken through the inductor and quenching jacket of Fig. 1 along the line II-II thereof;

Fig. 3 is a section taken through the inductor and quenching'jacket of Fig. 1 along the line IIIIII thereof;

Fig. 4 is a section taken through the quenching jacket of Fig. 1 along the line IIIIII thereof, the inductor being removed to disclose details of the quenching jacket;

Fig. 5 is a developed side view of the inductor of Fig. 1 together with part of the bus bar supports, the quenching jacket being removed to clearly define the inductor;

Fig. 6 is a plan view of a divided inductor and quenching jacket illustrating another embodiment of the invention;

Fig. 7 is a section taken through the divided inductor and quenching jacket of Fig. 6 along the line VII-VII thereof;

Fig. 8 is a detail section of a part of the divided inductor and quenching jacket of Fig. 6 taken along the line VIII-VIII thereof;

Fig. 9 is a developed diagrammatic view of a cooling tube forming part of the divided inductor shown in Fig. 6, together with a fragment of the bus bar support;

Fig. 10 is a diagrammatic section taken through a quenching jacket and inductor comprising another embodiment of the invention in which --th quenching jacket and inductor are closely joined;

Fig. 11 is a developed view of a portion of an inductor only, part of the inductor being broken away to clearly disclose the structure thereof, illustrating still another embodiment of the invention.

As shown in Fig. 1, the induction heating apparatus comprises an inductive member or work coil 52 having a loop l3, the outer periphery of which is substantially enclosed by quenching means comprising a quenching jacket M of arcuate shape. The loop l3 of the work coil surrounds an opening 15 into which a workpiece, not shown, may be inserted for heating by induction. The coil I2 may be formed from electrically conductive tubing, preferably of silver or copper and of rectangular cross section. As

shown in Figs. 3 and 5, the coil l2 comprises two single turns of tubing [1, l8 joined in electrical multiple parallel connection by means of a pair of bus bars, I9, 20, to form the single the turns through which quenching fluid may inductive loop [3. The single turns of tubing l1, [8 are arranged coaxially one above the other in general register and displaced axially to afford an arcuate slot or passage 22 between pass to reach the workpiece, not shown. In addition to providing the opening or passage 22 between the turns, the turns of tubing ll, [8 afford conduit passageways 23, 24, respectively, through "which cooling fluid may flow independently of lation for a short distance from the loop I3 of the coil I2 and then are bent in the same direct1on, as shown in Fig. 5, to extend substantially parallel to the axis of the coil. The turn of tubing [8 has a similar pair of terminal end por- 5', tions 21, 28. turns of tubing I1, I8 by means of the'pair' of bus bars I9, 20, respectively equipped with fingers" working position, and the turns I'I, I8. of the coil I2 are supported in-spaced relation to provide the arcuate slot or passage 22 with a uniform width of. opening along its length. Furthermore, the connection of the turns I'I, I8 to the bus bars I9,

in the manner described provides a rigid inductor having multipleparallel current paths and a single inductive turn, the. parallel current paths being represented by the two single turns II, I8.

The quenching jacket I4, surrounding the outer periphery of the coil I2 and spaced therefrom, comprises, as shown in Figs. 3 and 4, an arcuate outer wall 32 and an arcuate inner wall 33 in parallel curved relation, horseshoe-shaped top plate 34,-and a horseshoe-shaped bottom plate 35,

all joined together to define a conduit 36 for the flow of quenching fluid therethrough. Plates 38, 39 close the respective ends of the quenching jacket I4, the plates 38, 39 being fastened to the inner and outer walls 32, 33 in any suitable manner, as by screws 40.

The quenching jacket I4 is made from an insulating material, such as a suitable plastic. As shown in Fig. 4, the top plate 34 and bottom plate are fastened to the walls 32, 33by screws 4|, but the fastening may be effected by any other suitable means.

The inner wall 33 of thequenching jacket I4 has a lesser width, measured in the direction of the axis of the coil I2, than the outer wall 32,

which difference in width affords in the jacket I4 around the inner wall 33 of the jacket I 4 in axially spaced relation but also are disposed beyond the axial reaches of the coil I2. the one central passage 44 are less than thedi'-' mensions of the passage 22 deflnedby thecoil turns II, I8.

As' shown in Fig. 1,. the quenching jacket- I is supported in spaced relation with the coil I2" by means of a pair of brackets 46, 47, respectively. adapted to follow the outer contour of the: bus bars I9, 28 and of the jacket I4.

into the bars I9, 20. might be made by any other suitable means. Screws engaging the outer wall 32 hold the brackets 46, 47 securely against the jacket I4.

Means for introducing quenching fluid into thequenching jacket I4 comprise circumferentially spaced openings 5I in the outer wall 32, into whichl.

are fitted couplings 52 for connection with a source of fluid, not shown. Similarly, cooling Electrical connectionis-m'ade to the The two arcuate The dimensions of" The brackets 46, 4'! are shown respectively fastened to thevbus bars I9, 20 by means of cap screws 48 threaded However, the fastening fluitfid introduc d into the ecu I-2- through the respective terminal portions-25;21 ofthe turns oftubingf I'F, I8 as shown in Fig; 5,- the fluid flowing through each of the turns I1; I8 in the directionof thearrows, and emerging through the termii'ial portions 28. If desired, terminal p rsons zen maybe interconnected so that the cooling fluid will serially flow through the turns In operation, the inductor'or work coil I2- isc'onnected to the currentleads" 54, 55 of an induction heater, not shown, the connection being here effected Z by bolting the-- bus bars I9, 20 re-' spectively to the current leads 54,- 55.

workpiece;- not shown,- is inserted inthe opening- I5- ofthework-coi1 I2'and the coil I2 energized by passing through it a high frequency current-.- An'alterhatin'gmagnetic flux is thereby generated in the work coi-l I2, which flux links the workpiece and by means of induced currentsrapidly raises theternperatur'e'of the workpiece. During thep'eriod the coil I2 is energized, cooling liquid is continuously circulated through the turns oftubing-IT,- -I-8' in order to limit the temperature rise of th'ecoil I2;

When the workpiece'has reached its critical temperature, the coil I2 52. through the passages-42,43 in the wall 33' and passes over the axial reaches'of the coil I2 into theopenirig I5 where it impinges onthe work piece; Quenching fluid ejected from the central" 1 passage 44 passes through the passage 22 defined sage 22 therein that the substantially laminar" flow' of quenching fluid from the jacket I4 ente rs* the opening I5 of thecoil I2 without im pingingon any portion of thecoil structure dur--" ingits passage through the coil "I2. In short, thecoil- I2 offers no impediment to the flow of quenching fluid, the fluid flows freely from the quenching jacket I4 into the opening I5 of the' coil I2 against the workpiece.

It'- is unnecessary to interrupt the flow of cool ing fluid either during the heatin cycle or during the quenching cycle, inasmuch as the flow of cooling fluid is independent of the flow of quenching fluid and the flow of current through the coil I21 The temperature of the quenchingfluid as it emerges from the jacket I4 is not effected by the power absorbed in the coil I2, since the cooling fluid passing through the coil I2 takes up the resulting heat.

air therebetween and by providing a relatively. thick inner wall 33 for the jacket I4, the quenching fluid is further insulated thermally from the' coil" I2.

In the alternative embodiment shown in Fig. 10, the quenching jacket 51 abuts the inductor member 58 so as to leave no intervening space" the passage 6I' actually guides the flow of fluid in its passage through the inductor member 58';

is deenergized and quenching fluid under pressure is introduced into the quenching jacket I4 by way of the couplings- Thequenching fluid is forcibly ejected" By spacin the jacket I4 from the coil I2 to afford a cylindrical layer of" accent:

In the further alternative embodiment shown in Fig. 11, the inductor member 63 comprises an inner wall 64, an outer wall 65, a top side wall 66, and a bottom side wall 61 defining therebetween a passageway 68 for the flow of cooling fluid, and a transverse wall 69 extending between the side walls 66, 61, the transverse wall definin a. passage 10 connecting the outer wall 65 with the inner wall 64 for the passage of quenching fluid therethrough.

Thus the work coil I2, of Fig. 1, can be constructed in the manner shown in the embodiments of Figs. 10 and 11 without departing from the spirit of the invention.

In the apparatus above described, the workpiece to be heated is inserted into the coil opening l either from above or below the coil H.

The coil opening I5 is limited to workpieces having configurations commensurate with the size of the opening, since the coil 12 is not itself separable. In order to heat any portion of a workpiece which has a configuration incommensurate with the size of the coil opening l5, such as a crankshaft or the like, an alternative embodiment of the invention, as shown in Fig. 6, is utilized, in which the heating apparatus is separable into two portions which can be clamped around any section of a workpiece commensurate with the coil opening, as for example, the bearing surface of a crankshaft.

The heating apparatus shown in Fig. 6 comprises a supporting bracket I2, on which is mounted an inductor or work coil 13 together with quenching means hereinafter described, the coil 13 and quenching means being divided into two similarly constructed conductive assemblies 15a, 15b capable of being separated for the purpose of inserting a workpiece, not shown, into the opening 16 in the 100p of the coil 13. The conductive assembly 151:. comprises an inductor half or inductor segment Na, and quenching means comprising a quenching jacket 18a. The conductive assembly 151) similarly comprises an inductor segment 11b and quenching jacket 18b. The work coil 13 is here shown in the working position, in which the two inductor segments Ila, 11b engage to form a single inductive loop for the passage of alternating current therethrough. Since the conductive assemblies 15a, 1% are substantially bilaterally symmetrical with the exception of the clamping means hereinafter described, the following description of one conductive assembly 15a will suffice to delineate the other conductive assembly 151), like parts in the two assemblies being indicated by the same reference character followed by an'identifying suflix a or b.

The conductive assembly 15a comprises an insulating block 59a in which a bus bar 800. for supplying current to the inductor segment 11d is partially iinbedded. As shown in Fig. 7, the segment Fla is carried by one end of the bus bar 80a which is of substantially rectangular cross section, and the bus bar 89a is hingedly supported at its other end by means of a hinge'pin or bolt 82a extending through the bracket [2. Provision is made for leading current to the bus bar 89a through a conductor 830. having a terminal portion 84a hingedly connected to the bus bar 80a between a bifurcated end portion 85a thereof. In order to insure a good electrical connection between the bus bar 80a and theconduc-' tor 83a, and furthenin order to impart mechanical rigidity to the conductive assembly 15a, the block 19a is also provided with a bifurcated hinge portion 86a closely fitting over and abutting the bifurcated portion 85a of the bus bar 86a, and held for movement therewith by clamping means comprising the bracket 12 and a nut 81a threadedto the hinge bolt 82a.

As shown in Fig. 6, the conductive assembly 15a is capable of being swung, in a clockwise direction about the bolt 82a as a center, from the working position shown to an open or nonworking position. In a similar manner the other conductive assembly 15b can be swung about the bolt 82b in a counterclockwise direction from the working position to the open position. Stops 88a, 88b are respectively provided for each of the conductive assemblies 15a, i512 so that the inductor segments Fla, 1119 can engage in proper.

shown in the developed View of Fig. 9, comprises a plurality of arcuate portions cw, 92a, 93a, and

94a, spaced in general register one from the other,

and joined in a mechanical series connection through mitered tubular sections 95a, 96a, and 97a inserted respectively between adjoining ends of the tube portions 91a, 92a, 93a, and 94a at right angles thereto. The tubing might have been bent from a single piece into a configuration approximating that of Fig. 9, but such a method of construction would not have resulted in the sharply defined corners made possible by jointly mitering the ends of the tube portions 9 I a, 92a, 93a, and 94a and the interconnecting sections 95a, 96a, and 91a. When connected as shown in Fig. 9, the tube portions 9m, 92a, 93a, and 94a provide a conduit for the flow of cooling fluid therethrough, the direction of flow being indicated by the arrows.

The outer tube portions 9 la, 95a of the inductor segment Ila. are considerably longer than the intermediate tube portions 920;, 93a and are carried back along one side of the bus bar a,

as shown in Figs. 7 and 8, to the region of the hinge connection, where the tube portions 9la, 94a are suddenly bent to extend in parallel at right angles to the bus bar, as best seen in Fig. 6.

.That part of each tube portion cm, 940. lying along the bus bar 86a is secured thereto by brazing or the like.

Similarly, the interconnecting tube section a is brazed to the tip of the bus bar 80a, thus insuring, together with the brazed portions of tubing 91a, 94a, a strong support for the inductor segment 11a.

A contact mm, preferably of silver and having a rectangular shape, is placed across the end of the segment 11a comprising the interconnecting tubing sections 96a, 91a, and securely fastened thereto, as by brazing the contact Mild, to the sections 96a, 91a. With contact lilla in place, the segment 11a comprises a plurality of parallel current paths represented by the tube portions 9l a, 92a, 93a, and 94a. Furthermore, the tube portions 9m, 92a, 93a, and 94a, together with the sections 95a, 96a, 9m and the contact lllla,

now define a plurality of arcuate slots or passages 102a, 103a,. and Ma leading through the segment Ha.

.As shown in Fig. 6, the contact IOIa extends radially of the coil I3 into the passage between the conductive assemblies 15a, 15b. In this position the contact I!) Ia abuts a portion of the plate of the inductor segments Ila, 'i'ib is insured when the conductive assemblies 15a, I'5b are locked in the working position, as hereinafter described.

The quenching jacket 1811,, a portion of which Surrounds the outerperiphery of the inductor segment Fla and is spaced therefrom, comprises, as shown in Fig. 6, a portion of the block 19a having a bight I05a therein conforming substan .tially to the contour of the outerperiphery of the inductor segment l'la. An arcuate channel IIlBa for the flow of quenching fluid is so cut in the block 19a adjacent the bight l65a as to leave an inner wall IUIa in the block facing the segment Ila. Plates 108a, I691; respectively close off the ends of the arcuate channel IOBa.

A longitudinally-extending riser channel Illa is cut in the block 'igaadjacent to the arcuate channel 106a and connected therewith by means of a plurality of radially extending channels I I2a.

One end of the riser channel I I Ia is closed by a plug I I3a. The other end of the riser channel I I la communicates with an opening Had in the block Isa. The opening II Ia provides means, indicated in part by a fragment of a pipe nipple I I-3a, for introducing quenching fluid into the block 29a from a source, not shown.

A cover plate H111 and a bottom plate 811 of insulating material and having, respectively, edge contours conforming to the edge contour of the bight I65a are attached in fluid tight relation to the jacket portion 18a of the block 19a by any suitable means, as by the use of a suitable adhesive or thermosetting plastic, the plates II'Ia, I I8a providing top and bottom walls for the channel IIlSa.

As shown in Fig. 7, the inner wall IIl'Ia of the block surrounding the inductor segment 11a is pierced by a plurality of arcuate parallelly disposed passages II9a, I20a, and I 2I a through which the arcuate channel I060, can discharge quenching fluid into the region of the bight "lid. The passages IIQa, I20a, and I2Ia are so constructed and arranged as to be respectively in general register with the corresponding passages I 02a, I 03a, and H340. through theinductor segment (1a. The dimensions of the passages I02a, I03a, and I04a in the inductor segment 11a are greater than the dimensions of the passages I I9a, I2Ila and I2Ia through the block wall IOIa so that the substantially laminar flow of quenching fluid ejected throughthe passages II9a, I20a, and I2Ia of the block 19a will pass through the inductor segment IIa without impinging on any portion thereof.

Means is provided for clamping the two conductive assemblies a, 15b in conductive engagement when the assemblies have been swung to the working position, asshown in Fig. 6. The clamping means comprises a bail I23 pivotally mounted on an extension I24 of the conductive ,10 assembly 151), the bail having a resiliently-supported transverse member I25 adapted to engage an extension of the other. conductive assembly 15a when the bail I 23 is swung into the clamping .position shown. An operating, handle I26 integral with the bail I23 is provided for swinging the bail I23 into and out of the clamping position.

Means for locking the bail I23 in an open position when the conductive assemblies 75a, 1511 have been separated is provided. The locking means comprises a pin I21 pivotally mounted on extension I 24 of the conductive assembly 15b, the pin I21 having a detent I29 adapted to intercept a lug I30 on the handle I26 when the pin I2! is biased counterclockwise as far as it will go,

as for example, when the conductive assembly locking the bail I23 in the open position, the detent I29 holds the handle I26 in an extended position whereby the handle I 26 can be used for swinging the conductive assembly 1519 about its pivotal bolt 82b.

How the work coil I3 operates to inductively heat and to quench a workpiece will appear from the following description of such an operation.

Starting with the work coil I3 in the closed position shownin Fig. 6, the operating handle I26 is swung in a counterclockwise direction unclamping the conductive assemblies 15a, 15b, whereupon the conductive assembly 15b is swung to the open position. If more space is required for inserting a workpiece between thetwo conductive assemblies 15a, 15b, the other conductive assembly 15a can also swing into the open position. A workpiece not shown, is then centrally positionedbetween-the conductive assemblies 15a, 15b so that upon closing and clampin the conductive assemblies 75a, 15b the workpiece has the section thereof which isto be heat treated enclosed by the loop of the work coil I3.

After the conductive assemblies 15a, 151) are clamped in-working position with the inductor segments 11a, 11b electrically engaged to form aconductive loop, the work coil 13 is energized, thereb heating the work piece. The current flow is through the conductor 83a, the bus bar a, the, multiple parallel paths provided by the segment 11a, and similarly through the other segment Til), the bus bar 80b, and the conductor troduced into the quenching jacket 18a. viathe pipe. nipple. 5a. flows, into the riser channel II Ia where it isdiverted into the radially extending channels I,I2a. From the channels I [2a the fluid flows into the. arcuate channel 106a from which it is forcibly ejected through the ,arcuate .slots or passages IISa, a, and I,2Ia. In a similar manner, the quenching fluid flows through the quenching jacket 181).,

Following the quenching of the workpiece the operating handle I26 is swung to unclamp the conductive assemblies 15a, 15b which are then .swung about their respective pivots 82a, 82b; to

the open position. The workpiece then removed; a new workpiece is inserted and the cycle of operations just described is repeated.

During the heating and quenching periods, and during the period in which the conductive assemdescribed operation. The provision of separate tubing'for the flow of cooling fluid in each coil assembly makes possible this continuous circula- -.tion of cooling fluid. There is no mingling of the cooling fluid with the quenching fluid. The flow of each is entirely independent of the other.

Although several embodiments of the present invention have been herein illustrated and described, and although these embodiments have .been described particularly in connection with single-turn inductors, it will be apparent to one skilled in the art that the invention may have desirable functional utility in multiple-turn inductors, i. e., inductors having more than one inductive turn in series connection. And it 'should be understood that the invention of the assemblies; means for supporting said assemblies in mutuall conductive engagement; each of said assemblies comprising a conductive arcuate segment and fluid quenching means associated in insulated and spaced relation with said segment, said segment comprising a tube for the continuous flow of cooling fluid therethrough, said tube comprising an array of adjacent parallel arcuate portions in general register and means for con- "necting said tube portions in hydraulical series connection, and means for connecting said tube portions in electrical parallel connection, said electrical connecting means cooperating with adjacent said tube portions to define at least one arcuate slot between said adjacent tube portions;

said quenching means comprising a conduit for providing a source of quenching fluid under pressure, said conduit comprising an arcuate wall portion facing said segment, said wall portion defining at least one arcuate fluid passage having a transverse width less than the transverse width oisaid slot in said segment, said one passage being in general register with said one slot for forming and directing a sheet of quenching fluid freely through said one slot whereby said quenching fluid passes freely between said tube portions,

2. Means for inductively heating and for quenching a workpiece comprising: a dividable inductor comprising a plurality of conductive assemblies; means for supporting said assemblies in mutually conductive engagement; each of said assemblies comprising a conductive segment and fluid quenching means associated with said segment, said segment comprising a tube for the continuous flow of cooling fluid therethrough,

said tube comprising an array of adjacent parallel portions and means for connecting said tube portions in hydraulical series connection; and

12 trical parallel connection, said electrical connecting means cooperating with adjacent said tube portions to define at least one opening between said adjacent tube portions; said quench ing means comprising a conduit for providing a source of quenching fluid under pressure, said conduit comprising a wall portion facing said segment, said wall portion defining at least one fluid passage in general register with said one opening for forming and directing a stream of quenching fluid freely through said one opening whereby said quenching fluid passes freely between said tube portions.

3. Means for inductively heating and for quenching a workpiece comprising: a dividable inductor including a tube for the flow of cooling fluid therethrough, said tube comprising adjacent parallel portions and means for connecting said tube portions in hydraulical series connec-- tion; means for connecting said tube portions in electrical parallel connection, said electrical connecting means cooperating with adjacent said tube portions to define at least one opening between said adjacent tube portions; and fluid quenching means associated with said inductor, said quenching means comprising a conduit for providing a source of quenching fluid under pres sure, said conduit comprising a wall portion facing said inductor, said wall portion defining at least one fluid passage in general register with said one opening for forming and directing a stream of quenching fluid freely through said one opening whereby said quenching fluid passes freely between said tube portions.

4. Means for inductively heating and quenching a workpiece comprising: a dividable inductor including a tube for the flow of cooling fluid therethrough, said tube comprising adjacent parallel portions and means for connecting said tube portions in hydraulical series connection; means for connecting said tube portions in electrical parallel connection, said electrical connecting means cooperating with said tube portions to define a plurality of openings between said tube portions; and fluid quenching means associated with said inductor, said quenching means comprising a conduit for providing a source of quenching fluid under pressure, said conduit comprising a wall portion facing said inductor; said wall portion defining a plurality of fluid passages, each of said passages being in general register with a respective one of said openings for forming and directing a stream of quenching fluid freely through said one of said openings, whereby said quenching fluid passes freely between said tube portions.

JOHN A. EVANS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,687,656 Brown Oct. 16, 1928 2,145,864 Denneen et al. Feb. 7, 1939 2,244,056 Denneen et al. June 3, 1941 2,271,916 Denneen et a1 Feb. 3, 1942 2,277,223 Goodridge Mar. 24, 1942 2,356,150 Denneen et al. Aug. 22, 1944 FOREIGN PATENTS Number Country Date 485,651 Great Britain Sept. 20, 1937

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