US2900488A - Arc welding guns with consumable electrode wire - Google Patents

Description

ARC WELDING GUNS WITH CONSUMABLE ELECTRODE WIRE Filed Nov. 9, 1955 A. BASSOT 2,900,488

2 Sheets-Sheet l 27 6' I l 25 I i Q a Fig.2

INVENTOR ANDRE BASSOT B AM,

ATTORNEYS United States Patent ARC WELDING GUNS WITH CONSUMABLE ELECTRODE WIRE Andr Bassot, Boulogne-sur-Seine, France, assignor to LAir Liqui'de, Societe Anonyme pour lEtude et Exploitation des Procedes Georges Claude, Paris,

rance Application November 9, 1955, Serial N 0. 545,912

Claims priority, application France November 18, 1954 3 Claims. (Cl. 219-130) The present invention concerns arc welding guns with a consumable wire which may constitute the electrode, which is then consumable, or which may be distinct from the electrode which is then not consumable. The invention particularly relates to guns of the general type in which the gun body supports both a mechanism for moving the wire and a motor for driving said mechanism.

The latter comprises, generally, two rollers between which the Wire to be driven passes. The motor is an electric motor the shaft of which can be coupled with the driving roller of the driving mechanism only by means of a costly speed reducer, the weight and bulk of which add to those, already important of the motor.

A main object of the invention is to obviate these drawbacks. Another object is to arrange the parts of the welding guns of the above general type and of the associated equipment with .a view to improve their convenience in use. The invention is characterized chiefly in that the motor for driving the mechanism which drives the consumable wire on the gun is a volumetric hydraulic motor supplied with driving fluid from a source outside the gun.

From this principal definition of the invention it may be noted that:

A hydraulic motor may be built entirely of light mate rials (light alloys and plastics) and consequently does not substantially increase the weight of the gun;

It may, with a suitable choice of the pressure of the driving fluid, operate at a high torque with a reduced speed of rotation, which makes it possible to omit the speed reducer of the wire driving mechanism;

The adjustment of the speed of the volumetric motor is easily obtained by an adjustment of the flow rate of the driving fluid, and this whatever may be the variations in pressure.

The invention has for further objects to provide an arc welding gun in which:

(a) The source of fluid for supplying the hydraulic motor for driving the wire is a volumetric pump driven by an electric motor and preferably a capsule type pump, and, for instance, a gear pump.

(b) The hydraulic motor is preferably of the same type as the pump when the latter is reversible.

(c) The fluid pumped and forced towards the motor is utilized, at the output from the latter, as a cooling medium for the gun, the cooling circuit for the gun then coinciding, partly at least, with the circuit of the pump and of the hydraulic motor.

(d),The volumetric pump is driven by a constant speedelectric motor, and the output of the hydraulic motorwhich determines the speed of displacement of the "ice the displacement of this same wire, provided on the gun.

(g) The motor driving the wire-pulling mechanism ac cording to (f) is the electric motor controlling the pump which supplies the hydraulic motor provided on the gun.

(h) The mechanism for pulling the wire, according to (f) is a hydraulic motor mounted on the delivery side of the pump in series with the hydraulic motor provided on the gun.

Other objects of the invention will be set forth in the following description of various examples of embodiment of this invention, represented in the accompanying diagrammatic drawings wherein:

Figure l is a diagrammatic assembly elevation, with sections of a first form of embodiment of an arc welding gun, with a consumable electrode using a protective gas.

Figures 2, 3, 4 and 5 show the general arrangement of the main elements of an arc welding station with welding wire, using an improved gun according to the invention.

As explained above, the invention consists mainly in driving the mechanism for actuating the welding wire which constitutes a consumable electrode, by a volumetric hydraulic motor mounted on the body of the gun and supplied with a driving fluid under pressure by any suitable outside source, and preferably by a volumetric pump.

The invention relates particularly to the combination, with the welding gun, of a volumetric hydraulic motor consisting of a gear pump with a reversed circuit for acting as a motor, and supplied with driving liquid by a gear pump driven by an electric motor.

The gun shown in Figure 1 is designed for welding in a protective atmosphere, and with cooling by a water circulation. The wire 1, which constitutes the consumable electrode, wound otf a remote reel, passes through a flexible sheath 2 connected with the gun, and engages guiding elements 3 and 4 arranged on either side of two driving rollers 5 and 6; it comes out of the gun in a contact part 7 connected with the part 4 through a conducting tube 8 around which a sleeve 9 is provided for the circulation of the cooling water. A bathe-sleeve 10 determines the direction of this circulation, for which the inlet is at 11 and the outlet at 12 through a duct 13 provided in the handle 14 of the gun and in which a cable 15 is arranged for feeding electric current to the contact parts 4 and 7. Argon, which constitutes the protective gas for the welding arc is brought through the output nozzle 16 of the gun, through the duct 17 in the handle and through the annular space 18 between the sleeve 9 and the sleeve 19.

According to the invention, the driving roller 5 which, with the pressing roller 6 pulled back by a spring in a known manner, constitutes the mechanism for the motion of the wire 1 is driven by a volumetric hydraulic motor which, in the example of embodiment considered, is a gear motor mounted on the body of the gun. According to one feature of the invention, the driving roller 5 is coupled directly with the motor, i.e. without any intermediate speed reducer. To this effect it may be keyed directly on the outer extension on one of the axles of the pinions 20 of the motor 21. Consequently, the arrangement of the motor and wire driving mechanism on the gun may have a very small bulk and, in any case, considerably smaller than that of an electric motor of the same power with its speed reducer. The weight also is substantially less in the case of the invention, since, in addition to the omitting of the speed reducer, the hydraulic gear motor or the like does not require heavy metals like copper but may be made out of light metal alloys and plastic materials of low specific gravity. It is obvious, further, that the circuit for the circulation or" the driving fluid for supplying the motor being identical with the gun cooling circuit, the power supply to the motor is ensured with no weight increase as compared with a water cooled gun, everything else being the same.

The supply pump 22 for the motor is placed, for instance, on the fixed stand which supports the reel 2.3.from which the wire 1 is led to the gun through the flexible sheath 2 (Figures 1 and 2). It is connected, on its suction side, at 24, with a cold water source of a suitable type and its delivery side is connected through any suitable flexible pipe 25 with the input 26 to the motor 21 placed on the gun and the output of which 27 is connected to the inside of the sleeve 9 (Figure 1). The pump 22 is driven by an electric motor 28 coupled with the pump either directly or through a suitable reducer.

In the case of the diagram of Figure 2, the Wire 1 is wound off the reel 23 by the pull exerted by the rollers and 6 mounted on the gun, but there may be provided, also, as in the case considered in the diagram of Figure 5, a pulling mechanism consisting, for instance, of two rollers 5a and 6a and placed between the wire reel 23 and the pulling rollers 5--6 provided on the gun. These rollers 5a6a are placed, for instance, at the entrance to the flexible sheath 2 connected with the gun at 3a (Figure 1). In this case, the driving roller 5a is conveniently coupled with the shaft of the pump and the conditions are so determined that the speed of the linear displacement imparted to the wire 1 be the same at the outputs of each pair of rollers or that, preferably, the speeds at the output from the rollers 5a6a be slightly less than that at the output from the rollers 56 on the gun. The arrangement of the adjusting means for that speed varies according to whether a variable or constant speed electric motor 28 is used. In the first case it is sufficient to adjust the speed of this electric motor by means of any one of the devices already used in known arc welding stations.

If a constant speed electric motor is used, the following solutions may be used:

An adjustable output pump is used;

A constant output pump is used.

In the second case, the liquid fiow rate delivered to the motor is varied by shunting the latter. It is possible, amongst other arrangements, to adopt that indicated in the diagram of Figure 3. In this arrangement, the hydraulic motor 21 is shunted by a derivation on which an automatic element is interposed for controlling the section of the passage offered to the liquid. This arrangement is constituted, for instance, by a differential piston 2929a, one end 29a of which forms a valve movable with respect to a fixed seat 30. For a given pressure in the conduit 25 the piston is in equilibrium under the thrusts applied on each one of the two different areas 29 and 29a and by the spring 31. The reaction of the latter is adjusted by the screw- 32 or other movable stop. This equilibrium position of the piston corresponds to a given opening of the valve 29a and consequently to a predetermined liquid flow rate through the conduits 25-13 and 333333 and to a given speed of the motor. If the load applied to the latter varies, and if the speed of the motor tends to decrease or to increase in consequence, the pressure inside the conduit 25 rises or drops and the piston 29-29a is moved in the suitable direction for moving the flap 29a for bringing back the speed of the motor 21 to the set speed.

In case of an accidental blocking of the wire driving mechanism, and of a stopping of the motor 21, a delivery valve 34 loaded by an adjustable spring 35 allows the water to pass from the conduit 25 to the conduit 33 and to the cooling circuit for the gun.

The diagram of Figure 4 corresponds to that of Figure 3 but when unwinding rollers such as 5a--6a (Figure 5) are used at the outlet from the wire reel 23, these unwinding rollers being no longer driven by the pump 22 as 4 in the case of Figure 5 but by a motor 21a (Figure 4) identical with the motor 21 which drives the rollers 5-6 mounted on the gun. The two motors 21a and 21 are mounted in series in the delivery of the same pump 22 driven by the constant speed electric motor 28. The adjustment of the speed for the two motors simultaneously is effected by means of the differential piston 2929a, the operation of which remains that described motor mounted on said body and directly coupled with said mechanism, a volumetric pump remote from the gun body and having its outlet connected to the inlet of said hydraulic motor, an electric motor for driving the pump, and means for supplying said pump with a hydraulic fluid, said hydraulic fluid being used also as a cooling medium for the gun body.

2. In an electric arc welding gun with a consumable electrode wire moved through the gun, a gun body provided with means for guiding the wire, with a mechanism for moving the Wire and with means for supplying said Wire with an electric welding current, a hydraulic motor mounted in the body gun and operatively coupled ith said mechanism, a hydraulic pump remote from the gun body, the outlet of said pump being connected to the inlet of said hydraulic motor, means for supplying said pump with a hydraulic fluid, a constant speed electric motor for driving the hydraulic pump, and a bypass device adapted to shunt the hydraulic motor and including a valve responsive to the pressure of the fluid forced into the hydraulic motor by the pump for keeping constant the speed of said hydraulic motor.

3. In an electric arc-welding gun with a consumable electrode wire moved through the gun and fed to the latter by a mechanism driven by a variable speed electric motor, a gun body provided with a means for guiding the wire, with a mechanism for moving the Wire and with means for supplying said Wire with an electric Welding current, a hydraulic gear motor mounted on said body and directly coupled with said mechanism, a volumetric pump remote from the gun body and having its outlet connected to the inlet of said hydraulic motor, said pump being driven by the electric motor provided for driving the mechanism which feeds the electrode wire to the gun body, and means for supplying said pump with a hydraulic fluid, said hydraulic fluid being also used as a cooling medium for the gun body.

References Cited in the file of this patent UNITED STATES PATENTS 1,731,502 Paterson Oct. 15, 1929 2,190,927 Kennedy Feb. 20, 1940 2,278,975 Crawford Apr. 7, 1942 2,391,972 Huiford Jan. 1, 1946 2,423,190 Kennedy July 1, 1947 2,490,593 Kay, Dec. 6, 1949 2,526,035 Miller Oct. 17, 1950 2,596,708 Moore May 13, 1952 2,606,267 McElrath Aug. 5, 1952 2,753,688 Bunch July 10, 1956 FOREIGN PATENTS 132,651 Australia June 2, 1949

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