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Publication numberUS1760155 A
Publication typeGrant
Publication dateMay 27, 1930
Filing dateMay 16, 1923
Priority dateMay 16, 1923
Also published asDE408071C
Publication numberUS 1760155 A, US 1760155A, US-A-1760155, US1760155 A, US1760155A
InventorsAngus S Macdonald, Huggins E Melville, Charles C Waite
Original AssigneeSnead & Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electric heating apparatus
US 1760155 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

May 27, 1930.

AA.S.IWACHDCHQALI)E`AL ELECTRI C HEATING APPARATUS Filed May 16, 1923 5 Sheets-Sheet May 27, 1930. A. s. MACDONALD Er AL 1,760,155

ELECTRI C HEATING APPARATUS Filed May 16, 1923 5 sheets-sheet 2 May 27:, 1930.


Our invention relates to electric heating apparatus, and to heating etected by passage of electric current through the objects or pieces to he heated; and it is especially convenient and advantageous for the treatment of conductive pieces of substantially uniform section, such as metallic bars or rods.v We

. aim not oniy to enable heat treatment of such pieces to loe carried out in this manner with great accuracy and uniformity, and at the same time very easily and quickly, but also to providea very simple, convenient and reliable treating apparatus of novel type and construction.

vHow these and other objects and advantages can he realized through our invention wiii appear from our description hereinafter of the heet apparatus for the purposes of the invention now known to us. In this description, we have referred particularly to the employment of the apparatus tor annealing hollow rods or tubes by merely heating them up to a proper annealing temperature by passage o?? current, and yshutting o the current the moment such temperature is reached,-

without the proionged soaking at annealingv heat Jiound essential in former methods oi anneaiing,-as set forth in the appiication of A. S. Macdonald, Serial No. 625,260, filed March 15, 1923, and assigned to the assignee oi this application. However, it will be understood that our present invention and the apparatus here shown and described can also be adapted and applied to other obg'ects than tubes, and to other 'sorts of heat treatment than annealing. l

In the drawings, Fig. 1 is a side view of our preferred form of machine or apparatus with a tuhe or rod to be heated therein, the intermediate portions of machine frame and tube being broken away for the sake of compactness, and the superjacent structure at the right-hand end oi the machine being in longitudinal vertical section substantially as indicated by the line 1-`1 in Fig. 3.

Fig. 2 shows a cross section through the machine trame and the associated structure at the lett of Fig. 1, taken as indicated by the .line 2-2 in l.

Fig. 3 is an endwise view of the structure at the right of Fig. 1 as it would appear to I one looking to the right from the the midst of Fig. 1.

Fig. 4 shows a vertical longitudinal midsection through the structure at the right of Fig. 1, on a largerJ scale, taken as indicated by the line 4-4 in Fig. 5.

Fig. 5 is a plan view of the structure shown in Fig. 3, certain upper parts being broken away or removed as indicated by the line 55 in Fig. 4.

Fig. 6 is a fragmentary acial view of an indicating and actuating device shown yin Figs. 1 and 5, on a iarger scale; and

Fig. 7 is a wiring diagram, illustrating the operation of the apparatus.

Referring to the drawings generality, and particularly to Fig. 1, it wiil be seen that the apparatus illustrated comprises structures 10, 11 for taking the ends of the piece F and passing current through it, and also framing 12 (in the form oi stout timber ways with bracket leg supports 13), for supporting the structures 10, 11 and maintaining them in proper relative positions. in the machine here illustrated, the ways 12 are arranged horizontai and the end structures 10, 11 rest on them in such wise as to supportJ the piece P conveniently above them. The upreak in right clamping means 1e, 15 of the structures 10, 11 are open laterally, so that the pieces l) can be introduced and removed sidewise across the ways 12, 'from either side, or by successive movements in one direction, as preferred. 'Howeven the ciamping means may be arranged with openings in any direction found convenient e. g., they may be arranged in a horizontal position so as to be open vertically instead of laterally, so that pieces P can be ed into them sidewise by gravity from above and allowed to drop from them sidewise (either between or alongside the ways 12) into a bath below. As shown in Figs. 1, 2 and 3, the structures 10, 11 are in the nature of shiftable carriages or beds, with horizontal supporting ianges 15 hearing on the ways 12 and depending guide tianges 17 inside the latter. in order to 'facilitate adjustment of the left-hand carriage structure 10 along thea ways 12 `for' differences in length of pieces be treated, its supporting flanges 16 may be provided with anti-'frictlon wear.

2O that extend down from the structure 10,

and clamping screws 21 fast to handles 22 (with hubs 23 resting on the structure 10) extend down through the latter and work in threaded holes in said bar. When intended to remain stationaryl 'on the ways 12, the

right-hand structure 11 need not be provided with wear facings; and in some cases, its weight may also dispense with clamping means for holding it fast.

If referred, the carriage 11 may (as above implied) be allowed to remain in one fixed position, and Variation in length of pieces to be treated may be taken care ofby shifting the carriage 10, or, as an alternative mode of operation, the carriage 10 may always be left fixed in one position, and the carriage 11 shifted to take care of variation in length of ieces.

' revision for longitudinal expansion of the pieces P when heated is preferably made by having the right-hand clamping means 15 movable to the necessary extent relative to the ways 12 and to the portion 24 of the structure 11 that rests directlyon them. For this purpose, the clamping means 15 is in the present instance mounted on a bed or carriage 25 itself movable in guideways 26 (Fig. 3') on the more stationary structure 24. As shown in Figs. 1, 3, 4 and 5, these guideways 26 have a channel-like configuration, and the carriage 25 has vertical anti-friction rollers 27 that run between the. lower and upper sides of the channels (the latter of.

which are removable), and horizontal antifriction rollers 28 that bear against the upright bottoms of the channels. Thus the carriage 25 and its clamp means 15 are kept accurately in alignment with the other carria e 1() and its clamp means 14 at all times, an yet allowed to move along the'ways 26, 12Y

vwith minimum resistance.

l mounted in an opening in the web 34 of the stationary structure 24, on a spindle 35 in lugs depending from said web. By making the weight 30 suiiiciently heavy, considerable pull or tension can be exerted on the tube P through the carriage 25, so as to straighten out any slight bends while it is means softened fromthe heat. After each heat,

:the carriage 25 may be returned to the left to a proper definite initial position relative same way on their respective carriages 10,'

25, so that a description of the device 15 and its mounting will answer for both.

Referring, then, to Figs. 1, 3, 4 and 5, it will be seen that in the present instance the clamping means 15 comprises a sort of head structure (in shape resembling a yoke or a letter U resting on its side) with cooperating upper and lower clamp jaws 40 and 41. The flat, web-like lower member 42 of the yoke 15 rests and is bolted fast on the carriage 25 over an elongated longitudinal opening in its left-hand end. As shown, the electrical connections for passing Aheatingv current through the piece P are not made directly to the jaws 40, 41, but to the head 15 as a whole: accordingly, the latter is insulated from the rest of the carriage' 25- by means including a U- shaped sheet of insulation 43'interpos'ed between them. The electrical connection is made through a terminal 44 bolted and electrically connected to the yoke web or base 42, and of size to take the five-conductor lead 45. Preferably, the clamp jaws 40, 41 themselves serve as contacts or terminals for making direct electrical connection to the piece P, and are constructed to be heated bythe heating current for the latter,--as by making them of suitably limited cross section and of suitably highly resistant material, such as nichrome,-so as to prevent injurious cooling by the jaws that might often require the tube ends to be cut oi and discardedV because insuliiciently` annealed.

In lthe present instance, the upper jaw 40 consists merely of such a piece of high resistance metal mounted in vertical ways in the upper member of the yoke 15, which has a vset-screw 46 for adjusting the jaw, to vary its heating or for diiierences in size of pieces P, and a clamp 4'( Vfor securing it in adjusted position. The lower jaw 41 comprises such a piece mounted inl a metal part 50 that is guided in the vertical bore of a boss 51 depending from the. lower yoke member 42 (in the aforesaid longitudinal opening of the carriage 25), and is movable to close and hold a piece P fast, in effective electrical contact with both jaws, or to open and release the piece. Effective electrical connection `be tween lower jaw 41 and head 15 may be lower side of the yoke member 42 and to a lu 53 on the partv50.

peratingmeans for the lower jaw 51v may be preferably carried by the carriage 25,- and may be supported from the. head itself in order to obviate the necessity for insulating provisions. As shown, the jaw 41- is closed by solenoid or electromagnet 54 mounted in a depending frame 55 bolted to lateral lugs `56 on the yoke boss 51, and is opened by graVity,-aided, if desired, by a helical compression spring 57'acting between the lowel` side of the frame and an abutment58 screwed and locked fast on the lower solenoid core piece 59. When the solenoid 54 is equipped with the usual deenergizing means, gravity alone will generally be found to open it satisfactorily. When the solenoid 54 is ener gized, it raises the upper and lower core pieces 59 and 61, and (through a rod 62) the jaw parts 50, 41; when the solenoid is deenergized, the spring 57 forces down the part 59 through the bottom of the frame 55 as far as permitted by a pin and slot stop device 62a, and thus allows the superjacent parts to drop; This results in closure of an otherwise open auxiliary control switch 63 whose movable member is carried by the jaw part 50. Yl'fhe division of the solenoid core into the parts 59 and 61 prevents the full force due to the spring 57 from being exerted on the switch 63 when the jaw 41 opens. The function oi? this relay switch 63 will be explained'l'iereinater. lr preferred, in cases where tis not desired to rely on gravity 'alone' for opening the jaws, two solenoids standing in trent of the machine..

acting` in opposition may be employed: e. g., an amply poweriui one for closing and holding the Jaws shut, and a smaller one strong enough to open them promptly when the other is deenergised.

Stili referring to Figs. 1, 3, d and 5, it will be seen that in the machine illustrated provision is made for determining the heating period by the expansion of the piece P with the heat rising temperature due to the eurent passed through it. As shown,

f there is on the stationary structure 24ta rack 64; with which meshes a pinion 65 fast on the lower end of an inclined shaft or spindle 66 mounted in bearings on the carriage 25, and carrying an arm 67 at its upper end. As the carriage 25 is moved to the right by the expansion of the piece P, the arm 67 turns counterclockwise in a dat dial case 68 mounted on the carriage in a sloping position, so as to be conveniently visible to an operator p (Figs. 1 and t.) As the 67 moves, a point 70 t" sweeps over suitably graduated n) and thus atords a ot the temperature by which the operator may auge the proper moment for cutting oi the eating current. When the proper or maxi# mum allowablefinal annealing tem erature is attained, a contact 72 on the arm 6 strikes a contact 7 3 adjustable (along with a scalemarker 74) around the dial case 68,-thus effecting a circuit closure by whichan auditory or other signal can be produced, and by which (through a suitable relay switch) the heating current can be automatically shut off to insure against overheatinv.

In the present instance, the position of the carriage 25 for receivingY a piece P on its return by the treadle 36 after a. heat is definitely4 and accurately determined (and overtravel on the return movement prevented) by locking the carriage to the structure 24, by means of a spring-depressed steel bolt- 75 on the carriage (see Figs. 1, 3 and 5) adapted to slip into an accurately correlated steel-bushed socket hole 76 in the structure 24, and provided with an actuating lever 77 that raises the bolt when itself depressed. Preferably', also, a combined control is provided for operating the positiondetermining device 75, the heating current control, and the clamps 14, 15 in definite sequence. As shown in Figs. 1, 3, 5 and 7, the heating circuit and the operating circuit of the clamps 14;, 15 are controlled by self-closing, push-opened switches 78 and 79, respectively, conveniently inounted on the carriage 25 in proximity to the lock 75; and all three of these devices are actuated and controlled by a superjacent earn disc pivoted on the carriage at 81, and provided with a convenient operating handle 82. As shown in Figs. 1, 3 and 5, the controlier 8G has been turned clockwise from its position when pieces P are being changed far enough to first close the switch 79 and the clamps 14, 15 and then release and hold open the lock 7 5 and free the carriage. Slight further clockwise movement of the controller 8O will close the switch 78 and turn on the heating current,-as will be evident troni the dotted outlines ot the cam projections at the lower sideot' the disc in Fig. 5, and trom the full line cam outlines in Figs. 1 and 3. Reverse movement ot the controller 80 after a heat will first brealr the heating circuit, then iree the loclr 75 to ride on the structure 2d ready to drop into its socket 7 6 when the carriage 25 is subsequently returned by the treadle 36,-


reference characters as in Figs. 1 to 6, Yas a means of dispensing with merely repetitive descri tion.

As ere shown, the heating circuit 45 for the terminal jaws 40, 41 of the clamps 14, 15 is connected to the secondary of a transformer T whose primary is connected across A. C. power mains A (at 220 volts, say) by I a circuit breaker switch B. The control circuit b of the switch B includes the -contacts 72, 73 operated by the arm 67 in response to the expansion of the piece P and the movement of the carriage 25, as well as a source S of current at low potential (say 6 volts), such as a storage'battery. Whenthe contacts 72, 73 close the circuit b, the switch B opens the circuit t and thus shuts off the heating current from the piece P.

As the switch B opens the circuit t, it also closes an'auxiliary circuit n across Vthe mains A and thus brings into operation one or more annunciators N, N therein,here diagrammatically indicated as a bell and an incandescent lamp. At the same time, also, the switch B opens a shunt and connects a resistance r in the control circuit b, so as to prevent heating up of the solenoid winding of the switch B during the interval before the Y operator (if inattentive to the dial at 68) heeds the annunciator N and opens the contacts 72, 73 by returning the carriage 25,-'- or until these contacts are opened by the gradual cooling of the piece P. Before the operator can return the carriage 25, he 1s obliged, of course, to move the controller 80 counterclockwise,-thus breaking the primary heating circuit t. at 78, releasing the lock 75, and opening the switch 79 and the clamps 14,15, all as shown in Fig; 7.

The solenoids 54 for operating the clamps 14, 15 are connected in series across D. C. power mains D, by a circuit d that alsoincludes self-opening relay switches X and Y. When the operator opens the switch 79 by manipulation of the controller 80 as described above, he breaks the control circuit a: of the switch X (which is connected across the clamp circuit d)y and thus opens the circuit d and thev clamps 14, 15,-and vice-versa when he closes the switch 79. The auxiliary' 'the control circuit y of the relay Y; and when this switch .63 is closed by opening of the clamp 15, the relayvswitch Y closes and thus shunts a resistance Z that serves to prevent overheating of the solenoid winding 54 of the clamps 14, 15 while the latter `are closed. Thus the maximumurrent is available in the windings 54 for closing the clamps 14, 15 whenever their control switch 79 is closed by the controller 80;,while, on the other hand, the current in the windings 54 is automatically reduced to a lower value-thatthey can stand indefinitely without overheatingwhen all that is required is to hold the clamps closed against the opening tendency of the springs 57, Figs. 1, 3 an 4).

What we c aim is: 1. Apparatus for heating b current comprising horizonta ways; Ycaradjustable for diierencesin size of pieces and movable up or down to hold or release them, with springs for opening the lower jaws and solenoids for closingthem carried by said heads between said ways and with heating current leads'and effective electrical connections between leads and lower jaws;

means for exerting a pull on the piece throughthe movable carriage; means actuated by said movable carriage in response to expansion of the piece for determining the heating period; and means for shutting ofi' the heating current, controlling return of the carriage, and deenergizing the solenoids to release the piece, in automatically determined sequence.

2. In apparatus for heating by` passage of current, the combination of horizontal ways and a carriage movable along them with terminal and clamping means thereon for pieces to be treated, vmeans for moving said carriage one way as permitted by expansion of such pieces and exerting a pull on the ylatter', means for determining the heating pe- 'riod actuated by the movement of the-carriage movable along them with terminal and clamping means thereon for pieces to ybe treated, means on said carriage actuated `by its movement with expansion of such pieces for determining the heating period, means for deinitely determining the position of the carriage for reception of pieces, and a common' controller for heating current, position` determining means, and clamping means.

4. In apparatus for heating by passage of current, the combination or vways and a carriage movable along them with terminaland clamping means thereon for'pieces to be treated, means for locking said carriage in definite position on the ways, and a combined controller for heating current, locking means, and clamping means.

5. In apparatus for heating by passage of current, the combination of ways and a carriage movable along them with electrically operated clampng means thereon for passage of riages thereon, one adjustable for dierences '70 lac pieces to be treated, means for locking said carriage in definite position on the ways, control switches on said carriage 'for the heating current and said clamping means, and means on said carriage for operating heating switch, locking means, and clamp switch in automatically determined sequence.

6. Apparatus for heating by passage of current comprising horizontal ways, and laterally gripping clamping heads carried by said ways. laterally open at both introduction and removal of pieces to be treated sidewise across the ways, and provided with contact terminals for the pieces.

7. In apparatus for heating by passage` ot current, the combination of horizontal ways; a carriage shiftable along them ;4 a clamping head insulatively mounted on said carriage and provided with heating current connection and terminal jaws constructed to be heated by the current for heating pieces to be treated, one movable to hold or release the pieces; and means affording effective connection between head and movable jaw, -to

insure heating of the latter. y

8. 'In apparatus of the character described the combination of terminal clamping jaws for receiving an article to be treated, means 'tor passing a heating current through the jaws and the article to treat the latter, means vlor actuating said jaws including a solenoid and a circuit therefor including a power supply and a resistance element together with means actuated by movement of the solenoid for shunting said element when the jaws are in opened position. l

9. In apparatus of the character described the combination of terminal clamping jaws for receiving an article to be treated, means for passing a heating current through the jaws and the article to treat the latter, means for actuating said jaws including a solenoid and a circuit therefor including a power supply, a resistance element and manually operable relay switch means for controlling said circuit together with means actuated bymoveinent of said solenoid for shunting said element when the jaws are in opened position.

10. In apparatus of the character described the combination of terminal clamping jaws arranged to receive an article to be treated and support the same in a substantially horizontal position, means for passing a current through the jaws and the article to treat the latter and means for exerting a null lengthwise of the article through said jaws including suspended weight means and means for translating the downward pull of said weight means to a lengthwise pull on the article.

ln testimony whereof, we have hereunto signed our names. ANGUS S. MACDONALD. CHARLES C. WAITE. E. MELVILLE HUGGINS.

sides for

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2450362 *Mar 2, 1945Sep 28, 1948American Steel & Wire CoDevice for electric resistance heating of metals and controls therefor
US2465864 *Jun 22, 1943Mar 29, 1949Westinghouse Electric CorpAutomatic carbonization of filaments
US2606269 *Jun 12, 1948Aug 5, 1952Craig Jessie MFaller bar and method of making same
US3743778 *Sep 20, 1971Jul 3, 1973Park Ohio Industries IncResistance heating apparatus for elongated workpieces of varied lengths
US5744773 *Sep 19, 1995Apr 28, 1998Newcor, Inc.Resistance heating process and apparatus
US6037558 *Jun 30, 1998Mar 14, 2000Newcor, Inc.Integrated low inertia projection welding head and cylinder
U.S. Classification219/156
International ClassificationH05B3/00
Cooperative ClassificationH05B3/0004
European ClassificationH05B3/00A