US2297484A

US2297484A - Electrode holder

Info

Publication number: US2297484A
Application number: US359812A
Authority: US
Inventors: Lehrer Fritz; Wotschke Johannes
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-10-09
Filing date: 1940-10-04
Publication date: 1942-09-29
Anticipated expiration: 1959-09-29

Description

4 Sheets-Sheet l F. LEHRER ETAL ELECTRODE HOLDER Filed oct. 4, 1940 sept. 29, 1942.

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Jv* LL o` Sept. 29, 1942. F. LEHRER ET AL 2,297,484 ELEGTRODEl HOLDER I Filed Oct. 4, 1940 4Sheets-Sheet 2 Sept. 29, 1942. F. LEHRER ET A1. 2,297,484

` ELEGTRODE HOLDER Filed oct. 4, 1940 4 sheets-sheet s Sept. 29, 1942.

F. I EHRERy ET AL x-JLECTRODE HOLDER Filed Oct. 4, 1940 4 Sheets-Sheet 4 saggE I Patented Sepb29, 1942 v UNITED STATES; PATENT 1 OFFICE hannes Wotschke,' Berlin-Dahl em,Germany;

vested in the Alien Property Custodian 2 Claims.

The invention relates to electrode holders consisting of twospaced superposed clamping Jaw arrangements and with the aid of such.a pair of clamps the electrode held therein is automatically finely adjustable when being ied, without loss of gripping security in all operating and regulating positions. According to this invention the superposed clamping arrangements are connected with leach other, are positively locked and move in opposite directions preferably in such a manner that all force transmitting components are engaged only with respect to pull or pressure. The clamps may be provided with any number of jaws and also may be designed for current transmission, the part' holding the electrode being of a design known-for such purpose.

'I'he positively locked connection of the two clamps moving in opposite directions has the eiect that the gripof the lower clamp holding the electrode in operating position is'necessarily weakened in the case of a contemplated readjustment of the electrode but only to such a slight extent that the electrode moves relatively to such clamp and, in fact, tothe entire A holder owing to the fact that the .starting of the re-adjusting movement for loosening one of the clamps results in a corresponding pressingon effect of the other clamp. In consequence thereof the feeding movement may be nterrupted at any place and therefore may be as slight as desired. At the end of the adjusting movement the pressing-on force, stopping the electrode, will by itself increase again to the original value. The invention in view of this effect may be designated as a sliding holder with automatic regulation and ne adjustment. The drawings show the invention in several modes of construction in lateral view and the individual components in sectional view. Corresponding components in the various figures are provided with the same symbols.

Figure 1 shows a simple mechanical design of the new sliding holder.

Figure 2 shows a sliding holder with mechanical force-operated arrangement-'and common actuation of all re-adjusting members of the upper clamp. l

Figure 3 shows a hydraulically actuated sliding holder.

Figures 4, 5 and 6 represent in longitudinal section and greatly enlarged the bearing of a drawbar in various positions.

Figure 7 shows in centre longitudinal section with individual components a fourth mode of construction according 'to the invention.

In Figure 1 the electrode I., which simultaneously may be designed for current transmission, is spring held by jaws, the spring power being adjustable as to its value by means of a rod arrangement for subjecting the jaws to pressure. For this purpose the tension of spring 2 is transmitted in the casing 1 by way of the crosshead "trode will increase in keeping with the increase of the force acting in downward direction on the legs II of the tongs. With an upward movement of the tongs the mouth I4 of the tongs tends to open in response to the effect of the moment caused by the frictional force and thus opposes the upward movement by a but very small force scarcely impeding such movement. The bar 8, on which the spring 2 is exerting its compressive force, passes through this spring and its upper part is designed as a screw extending through the legs II of the tongs. Thusa travelling nut I0 which, on the one hand, is screwed onto the spindle 9 and, on the other hand, is rotatably connected to the leg II of the tongs, with a movement of the spindle 8 takes compulsorily with it the leg I I of the tongs. On turning the nuts simultaneously, for example, over a chain drive I3, the nuts will at rst move downward only as far as is permitted by the backlash. Downward ,sliding oil of the tongs is prevented by their automatic stopping. Thus, continued turning of the screws will result in a pulling force opposed to and weakening the spring power. The'pressure at the jaw 6 is thus reduced, but the downwardly directed weightv of the electrode I, having so far been balanced by the frictional force caused by the spring power at the jaws, is augmented by the reactive force transmitted by the tongs I4 to the electrode I, causing sliding of the electrode. The electrode continues to slide as long as the equilibrium is interfered with by the turning of the screws. On ceasing turning the screws I0, the force weakening the springs 2 caused by the turning of the screws will diserated eiect cannot occur with this movement between the tongs and the electrode.

The preferably water-cooled holding ring 8 may be either rigidly mounted or in known manner be moved up and down. One conventional method of mounting the holder together with the electrodes involves the use of the eyes I6 and cables I1 which run on pulleys I8 and can be wound up on the drum' I9 by a motor.

' This design requires but a very slight height. The electrode may be uniformly released by any amount without interrupting the current. But with known, types, although they are operating without current interruption but must completely release the jaws, there is danger of an electric are being formed between the jaws and the electrodes. This disadvantage is avoided by the invention.

In the design according to Figure 2 the electrode I is heldin rest position by the four jaws 6 of the lower clamp holder. For this purpose there are arranged in cups the springs 2 exerting a compressive eiect on the bars 9. The spring pressure is transmitted to the plungers 5 by means of the links 3 and the toggle 4. The arrangement 2 to 1 is accommodated in a cooled ring-shaped casing 1 carrying in its upper part removable and follower-like closed spring heads 3|).l Tension of spring 2 may be adjusted by adjustment of bolts acting upon spring head 30. At that place are also suspended in hinged arrangement the jaws 6. The upper clamp carries the jaws Il on bars or holders II on which are rotatably fastened the spindle nuts Ill. The chain I3 in this mode of construction serves for the common actuation of all the nuts I0.

In order to supply electric current to the electrode II, a current lead-in '23, water coolednis connected with the jaw 6.`- Numeral 24 designates the exible leads connecting lead-in 23 with a current source not shown.

jaws Ii are electrically connected to each other,-

said jaws being ilexibly suspended to the holding ring by means ofa link 20 and joints 2I.

Since the nature of the invention involves transmission of occurring clamping forces and liberating -forces in the mechanically simplest form, namely, by pulling forcesor compressing forces, and to keep the transmitting components at least theoretically free from bending stresses, importance is attached in all modes of construction to guiding all screw spindle bars 9 perpendicular and exactly parallel to one another. For thisreason also the legs of the vtongs (holders) which are rotating, though but slightly, around their axis of rotation-due for example to elastic deflection of the'holders, unequal thickness of the electrodes, blacklash at the axis of rotation et cetera-must be connected to the ball joint comprising the ball members I0 and ball cup III with the screw spindle bars by an intermediate member. The Figures 4, 5 and 6 show the eiective and extreme position of the ball joint -in exaggerated representation. The spindle system at the spindle heads is stiffened by a ring in consequence of the fact that in practical design 75 vare the spindle nuts III, the chain I3 serving for The various there are transmitted to the spindle also over the ball joint and the bearing surface, respectively, slight frictional forces between the ball cup and the nut, which would exert a bending strain on the spindle.

According to the invention the especially simvple` design according to Figure 3 embodies a nnemeans on piston 5u. through conduit 5b (shown on the left hand side of the drawing) and a spring 2, described in the foregoing, or an elastic pressure means, such as compressed air over the piston infequilibrium. as described in the foregoing. The upper clamps I4 are arranged in holders II (compare Figure 4); I3 is the common actuation f or the spindle nut I0. Nut I0 acts upon holder I I through angle member 29, see Figures 1 and 2 as well as Figure 3.

From a pressure means tank, not shown, is conducted a noncompressible medium (water, oil) through the shut-oil" valve 3I into the pressure cylinder communicating with the piston which is filled until the pressure piston assumes about the position shown in the drawings. When in this position the shut-olf element is closed and used later exclusively for reiilling if there has occurred a loss of pressure means. if any. The spring 2 is tensioned to such an extent that the pressure exerted by it over the pressure piston produces a bearing pressure of the piston 5 on the jaw 6 permitting of holding -the weight of the electrode. The mode of operation of the upper clamp is again the same. Turning the screw over a common driving means, for example, the chain I3, exerts a pulling force on the spindle 9, owing to the fact that the upper .clamp is self-stopping, and relieves the pressure piston whose reduced pressure adapts itself to the piston. The .pulling force' at the spindle transmitsitself as reactive force over the upper clamp to the electrode and increases the weight of the electrode--the electrode slides. The screws having been set at rest, the spring regains its original tension and thereby also the press' ing-on force will be regaining its original value which will he able to maintain the electrode in portingf ring Bare suspended the jaws 6-of the I the rest position. Equilibrium is re-established. The design according to Figure 7 shows an especially completely equipped development.

The circular casing 1 is designed as protective` jacket. At its cooled cover in form of the suplower clamp for vthe electrode I, simultaneously serving for current supply. The protective jacket 'I contains also the lower ends, loaded by the pressure springs 2, of the spindle bars 9, jointly carrying a wedge-shaped ring 32 coacting with the correspondingV counter wedges 22 cast or other-l wise attached on the outer surface of the jaws' 6. The sleeve I5 serving for permitting the passing of the screw spindle 9 through the carrying ring 8 serves simultaneously for affecting the tension their common drive. The perpendicular position of the spindle nuts Il) opposite the jaws I4 with the readjusting motion in the sense of the maintenance of. pure compression forces and pulling forces, is also secured in this mode of construction by a crowned intermediate bearing similar to that shown in Figure 4. The eyes I6 at the carrying ring 8 are serving for the suspension of the-entire arrangement.

The spring 26 of Figure 2 and the spring 26a of Figure '7 serve to increase 'the clamping effect of the tongs when the electrode is to be moved downward and it is necessary'toavoid lifting the tongs too far away from the electrode when nut I0 is traveling upward,

Corresponding to the designs described in the foregoing, in their rest position, namely, in the operating position, the jaws 6 of the lower main clamp are rmly pressed against the electrode I. For this purpose is serving the keying between the outer surface of the jaws and the wedgeshaped ring, assisted by the springs 2. When rotating the spindle nuts I0 by actuating the chain I3, so that the spindle 9 is lifted against the action of the springs 2, the pressing-on of the wedgeshaped ring and corresponding thereto the clamping effect of the jaws will be decreased. But at the same time the spring load of the spindle 9 and its nuts I0 will be augmented by the tension of the springs 2. The spindle nuts will press to the extent of their rotation over their crowned base on the holders of the auxiliary clamping jaws I4, pressed accordingly against thev electrode.

What is claimed isi 1. An electrode holder comprising, a main clamp designed as a current conduit for holding an electrode in operating position, means for supporting said main clamp, a secondary clamp axially spaced from said main clamp and adapted to act on another portion of an electrode, means normally pressing said main clamp into gripping position, and means acting on said last-named means for drawing said two clamps together and simultaneously displacing the pressure thereof from the main clamp to the secondary clamp to permit passage of the electrode through the former.

2. An electrode holder comprising, a main clamp designed as a current conduit for holding an electrode in operating position, means for supporting said main clamp, a secondary clamp laxially spaced from said main clamp and adapt--l ed to act on another portion of an'electrode, a

rod operatively connecting said clamps, a spring acting through said rod to normally bias the main clamp to gripping position and the secondary clamp to release position, and means for simultaneously shortening the effective length of said rod and compressing said spring to relatively move said two clamps toward one another and to displace the thrust of said spring from said main clamp to said secondary clamp to permit passage of the electrode through the former.

FRITZ LEHRER. 1 JOHANNES WOTSCHKE.