US1145642A - Apparatus for electric welding. - Google Patents

Description

H. R. WOODROW.

APPARATUS FOR ELECTRIC-WELDING APPLICATION FILED MAR/I3. I9I5.

2 SHEETSSHEET I.

ghi/tzeoow J7! Svwwwtoz Patented July 6, 1915.

H. R. WOODROW.

APPARATUS FOR ELECTRIC WELDING. APPLICATION FILED MAR. I3. ms.

1 ,145,642. I Patented July 6, 1915.

2 SHEETSSHEET 2.

I I 25 7 Z4 Z3 27 I lvwa z %1 alto away Y AM/ M HARRY woonRow, on NEW YORK,

N. Y., ASSIGN-OR TO THOMAS E. MURRAY, 01? NEW YORK, N. Y. I

APPARATUS FOR ELECTRIC WELDING.

Specification of Letters Patent; 7

Patented July 6, 1915..

Application filed March 13, 1915. Serial No. 14,193.

To all whom it may concern Be it known that I, HARRY R. WooDRow, a citizen of the United States, resldlng at New York, in the county of New York and State of New York, have invented a "certain new and useful Improvement in Apparatus for Electric Welding, of which the following is a specification.

The invention relates to electric welding, and consists in an automatic apparatus embodying an electric motor energized by the welding current, which motor controls the duration of said current. Means are provided whereby an initial duration of the Welding current is established, and thereafter this duration is controlled by the variations in resistance at the welding electrodes, which variations affect the speed of the motor to vary the duration of the cur-.

rent correspondingly to the resistance changes.

In the accompanying drawings Figure 1 illustrates generally my apparatus. Fig. 2

is an elevation, and Fig. 3 a plan view of a device for determining the duration of the welding current.

Similar letters, and numbers of reference Referring first to Fig. 1: A and B are two bars to be welded together at their ends. The bar B is held in a metal screw clamp O which is immovably held upon a plate D of insulating material which rests upon the base E, by means of an insulated screw bolt F. The bar A is held in a similar screw clamp G whichis slidable upon said plate D. On 7 the clamp G is a "projecting stud H.

I is a bell crank lever pivoted in a suitable fixed bracket J. Between the upright arm ofsaid lever and the stud H is interposed' a helical spring K. The other arm of said lever has a pm which enters a slot in the lever L pivoted in a fixed bracket M. On the opposite side of the bracket M a suspended weight N is attached to leven L'. The weight 'N is'to be of predetermined magnitude, and in order to adjust said magnitude it may be formed of disks a of metal, which can be varied innumb'er as desired. Said weight operates through the levers L, I toslide the clamp G toward the clamp C,

' and so to press the end of bar A against the end or bar B.. with a constant pressure,

which is rendered elastic by the interposed:

spring K. To the clamps (3 G respectively are connected the terminals of the secondary coil 1 of a transformer-2.

The source of welding current (not shown) is connected to the switch 3 which coeperates with the terminals 4, 5. Terminal 5 is connected to a brush 6 which bears upon a contact 7 on the periphery of a rotary cylinder 8 of insulating material. Terminal 1 is connected through the primary coil 9 of said transformer to a brush l0 bearing upon a contact 11 on the periphery of cylinder 8. The contacts 7 and 11 are connected by bar 12. The cylinder 8 carries a pinion 13, with which engages a worm 14: on the shaft of a motor 15, which is connected in parallel with the brushes 6 and 10. Instead of connecting the terminal 4 to the end of primary "coil 9, I may connect it to a pivoted switch lever 16 which cooperates with a plurality of contacts 17 connected to successive turns of said primary coil, so that by suitably adj usting said lever I may cut out one or more of said turns as desired. The relation of the primary and secondary conductors in said transformer is to be such that the strength of the current delivered at the secondary will be augmented.

The operation is as follows: The pieces A, B to be welded are inserted in the clamps G, C, and the weight N is adjusted so as to cause the end of piece A to press against the end of piece B with a certain predetermined pressure. The switch 3 being closed, a current of predetermined strength is delivered to said pieces at their joint. Said strength is. primarily'adjusted by suitably p'roportioning the primary and secondary coils 9 and ,1, and more closely adjusted by means of the pivoted switch lever 16 operated ,to cut one or more turns of the primary coil into or out of circuit. By

reason of'said current, the metal at the joint between pieces A, B is melted and a Weld is produced under the pressure exerted, as al-- ready described. The motor 15 is simultaneously set in operation to rotate the cylinder 8. When the contact plates 7, 11 on said cylinder touch the brushes 6, 10, circuit is closed through the bar 12 connecting said plates, to the joint to be welded, and this closure and hence the duration of the welding current continues until by the rotation of said cylinder, circuit is broken at said brushes. The period of rotation of said cylinder'may be'determined by varying the speed of the motor 15 and in this way- I can establish the duration of the. weldingcurrent. I

. It will now be obvious that bythisapparatus 'I am enabled (1) to determine the mechanical pressure at the joint to be Ywelded, (2) to determine the strength of the welding current, and (3) to determine the duration of said current. And thus I may give to each of these factors at the outset a predetermined value which may be governed by the contact areas of the. two pieces to be welded. Hence ifv theme mbers' of a lar e number of pairs of similar pieces are to e united, the conditions being adjusted for one pair will remain the same for all, succeeding pairs, and hence I'can effect a prac-.

tic'ally perfect weld in every pair entirely] independently of the personal equation of the operator. The control of the ti'mefactor is here of especial importance, since it is preferable to use a very strong welding current for a val may be but a fraction of a second, it is practically impossible to control it by manually operating a switch.- If the interval be made too short, an imperfect weld resultsif too long, the weldis apt to be burned and 0 again rendered imperfect, and besides v energy is wasted. Withautomatic controlof the time factor, as above described, the

interval may be adjusted with accuracy. Instead of regulating the duration of, the welding current by varyingv the speed of the motor, the contact pljates'7, 11 being set at an invariable distance apart, I-may do so i by varying the distance between the-contact plates on the cylinder 8, so that current will 7 remain established for a greater or less time-the speed of the motor then being constant; or I may vary both the speed of; the motor and the relative spacing of. the said contact plates. v a

In Figs. 2 and 3, I illustrate a circuit-. controlling device, in which the contact plates may be adjusted to vary the distance between them with much accuracy. The

motor 154is hereshown mounted on any. suitable insulating 'base 18.- The shaft 19 of worm 1% extends through the upright arms 20,21 of a bracket also mounted on said 'base. Collars 22 on opposite sides of the bracket arm 21 prevent endwise play of-said shaft, which carries a metal disk 23, 'on' the face of whichis secured a fixed arm 24 carrying the contact plate 11 and a pivoted arm 25 carryingthe contact plate. 7. On the pivoted arm is a proj'ectin plate 26' which.

receives the thrust of an a justing screw 27 loosened so that the distance" of plate 7 from 0: 5. plate 11 may be approximately adjusted by very short interval of time. As this inter-- which passes through a lug 28 on the face of lplate 23. There'is a nut and washer 29 on, the .pivot bolt' of arm 25 which is first justing screw 27 maybe used for setting said plate 7 with greater accuracy to any desired distance. For-convenience, the brushes 10 and 6 are here carried upon blocks 30 and 31 7'0 mounted on base 18 and provided with sockets 32 for the attachment of the circuit conductors. v v So long as the resistance-offered to the current at' the welding electrodes remains constant, the duration of the current will be regulated by the means described and will remain; corespondingly constant. But if, through any causeas, for example, scale on the welding faces-the resistance to the current increases, then the strength of'the welding current diminishes, and as it is this current which also actuates the motor, the motor speed decreases; so that the duration ofthe current is thus automatically increased to an extent proportionate to the resistance encountered at the welding elecf tro es.

welding current, and a device actuated by said-motor and interposed in-thecircuit of f said welding current for determining the duration of said current in said circuit.

3. An" apparatus for electric welding, comprising means for holding the welded in contact, circuit connectlons to-said holding means, a motor controlled by the welding current, and a rotary circuit breaker actuated by said motor. and interposed in the circuit of said welding. current for deter- 11o mining the duration of said current in said circuit. I I I 4. An apparatus for electric'we1ding,comprising means for holding the parts to be 'welded in contact, circult connections to '1 said holdingmeans, and two branches from" said circuit connections; a motor. controlled by the welding.- current one of said branches, a rotaxymember actuated by said parts to be motor, connected contacts on said rotary 1'20 member, and, in the other branch, fixed contactscodperating-with.said first-named contacts.- .apparatuiforieleetric welding, com

pri'sin means-for" holding the parts to be welde incontat'zt, circuit connections tosaid holding means, and two branchesq from said circuit connections; a motor controlled by thewelding current in one of saidbranches,

a "rotary member actuated by said motor,

connected contacts on said rotary member, means for varylng the dlstance between sald contacts, and, in the other branch, fixed contacts cooperating with said first-named con-* tacts.

y 6. An apparatus for electric welding, comprising means for determining a constant pressure of the contacts at the joint to be Welded one against the other, means for de- 10 termining'the strength of the Welding current supplied to said contacts, and means controlled by said current for determining the duration of said current.

In testimony whereof I have aflixed my signature in presence of two witnesses.

GERTRUDE T. PORTER, MAY T. MCGARRY.

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