US1761421A - Electrical welding apparatus - Google Patents

Description

lJune 3, 1930. E. J. VON HENKE 1,761,421

ELECTRI CAL WELDI NG APPARATUS Filed June 12, 1925 3 sheets-sheet 1 VII/l L/JATTORNEYJ Jim@ 3, 1930- E. .1. VON HENKE 1,76L421 ELECTRICAL WELDING APPARATUS Filed June l2, 192,3 3 Sheets-Sheet 2v [Ill INVENTOR /f' @ATTORNEYS June 3, 1930. E 1 VON HENKE 1,761,421

ELECTRI CAL WELDING APPARATUS Filed June l2, 1.925 5 Sheets-Sheet 5 INVENTOR v ATTORNEYS.

Patented June 3, 1936 UNITED 1?;i.. PATENT OFFICEv EDMUND J. VON HENKE, OF CHICAGO, ILLINOIS, ASSIGNOR TO AMERICN ELECTRIC FUSION CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS ELECTRICAL WELDING Arranz-frcs Application led June 12,

My invention relates to electric welding apparatus and particularly to spot Welders.

My invention will be betterunderstood by reading the following description taken in connection with the accompanying drawings forming a part thereof'and in which, Fig. 1, is a side elevation partly in section; Fig. 2 is a detail view of the 4controlling switch; Fig. 3 is a plan view of the electrode holder; Fig. 4 is a section on line IV--IV of Fig. 5 with the motor omitted; Fig. 5 is a plan view of the device shown in Fig. 4 with the motor added; Fig. 6 is a vertical section on line Vl-Vl of Fig. 5; Fig. 7 is a section showing the clutch operating mechanism; Fig. 8 shows the clutch in section; Fig. 9 is a view showing the clutch controlling mechanism and eccentric; Fi 10shows the roller cage of the clutch and ig.'11 is a section on line XI-X1 of Fig. 8.

Referring to the drawings particularly Figs. 1 and 2, the machine comprises a casing or pedestal 1 in which are placed the usual elements of a spot welder, that is, the autocoil 2, transformer 3,- regulator (not shown) and automatic switch 4. The secondary 5 of the transformer is connected at one end to the electrode holder 6 and at the other end to the electrode holder 7. The secondary is connected to the holder 6 by a socket 8 which is split and held firmly around the holder 6 by a bolt 9. The socket 8 is provided with a downwardly and rearwardlyextending flat projection 10. rl`his projection is provided with a plurality of openings through which bolts 11 pass. rThe secondary is provided with similar openings and is placed upon these bolts and nuts are screwed thereon. which securely fasten the end of the secondary to the projectionlO and thereby to the electrode holder 6. An insulating collar 12 is placed around the holder 6' and a sleeve of insulating material is placed on the end of the holder 6. A rocker arm 13 is securely fastened to the holder 6 by bolts 14 which pass through the upper half of a flanged socket which-is a part of the arm 13 and through the lower half 15 of the socket which is a part of a yoke 16. The yoke 16 is pivoted at one end to a lug 17 on the pedestal and 1923. lSerial No. 644,843.

at the other end to a similar lug on the other side of the pedestal. The other end of the rocker arm 13 engages a yoke 18 which carries rods 19 which extend downwardly and carry at their lower ends the automatic switch 4 which is shown in detail in F ig. 2. r1`he lower end 20 of the automatic switch is connected with one end 21 of a bell crank lever which is fastened to a shaft 22, journaled in the pedestal. The other end 23 of the bell crank vlever is connected to a link 24, the other end of which link is connected to a rod 25 which is adjustable in a socket 26 carried by a shaft 27 also journaled in the pedestal. The shaft 27 also carries a treadle arm 28 to which is connected a treadle 29. A-counterweight 30 is carried by the shaft 27 on a rod 31. The counterweight is adjustable on the rod 31 toward and away from the shaftl 27 The position of the counterweight 30 is such as to hold the parts in the positions shown in full lines in F ig. l.

The other end of' the secondary 5 is connected to a block 32 by bolts 33. The block 32 1 is provided with horizontal undercut grooves 34. A socket 35 is placed against the face of the block 32 and bolts 36 are passed through the socket and the heads of the bolts pass into the slots 34 so that upon tightening of nuts on the bolts the socket 35 is drawn tightly against the face of the block 32 so as to establish a good electrical contact. The socket 35, like the socket 8, is split and a bolt 36 is passed therethrough and when tightened securely holds the electrode holder 7 in the socket and in good electrical Contact therewith.

Electrodes 37 and 38 are held in the holders 6 and 7, respectively. 'llhese holders are arranged at their ends as shown in Fig. 3., that is to say, they are split and are provided with an opening 39 through which the electrode passes. A case-hardened nut 40 is set into one side of' the holder and a casehardened bolt passes through the opening 41 and screws into-the nut 40 so that the electrodes are firmly held in the holders. The holders are preferably of copper and are so soft that a thread in the copper metal would not be of sufficient strength to withstand the necessary strain.

The transformer 3 and autocoil 2 are attached to a pan 42 which is carried by the top of the pedestal 1. By this arrangement the transformer, autocoil, rocker arm, electrode holder 6, block 32 and electrode holder 7, may be removed as a unit from the pedestal. This arrangement permits of easy inspection and repair of the operating parts of the Welder. y

The automatic switch 4 is shown in der?. in Fig. 2. This switch comprises a yoke through which passes a member 44 carrying a Contact disc 45. The disc 45 is adapted to engage contacts 46 which are fastened in a cross piece 47 of insulating material. This switch is described in detail in my co-pending application, Serial N o. 560,734, filed May 13, 1922. The arrangement of this switch is such that upon the pressing down of the treadle 29 the end 26 of the automatic switch is moved upwardly. As this movement continues, the rocker arm 13 is rotated in a counter-cloclnvise direction as viewed in Fig. 1, until the electrode 37 engages the work which is placed between the electrodes 37 and 38. When the electrode 37 engages the work, the rocker arm stops. A further downward movement of the treadle 29, therefore, compresses a spring 48 whereupon the disc 45 moves upwardly into engagement with the contacts 46. These contacts control the primary circuit of the transformer 3. When the disc 45 engages the contacts 46 the current is turned on the machine and the secondary current passes through the work between the electrodes. A further downward movement of the treadle further moves the lower end 20 of the switch upwardly. When the lower end of the switch is moved up to a predetermined point a trip is sprung which releases the rod 44 and -permits the disc 45 to snap away from the contacts 46 and thus open the circuit whereupon current flow through the work ceases.

During the upward movement of the member 20 the spring 48 has become compressed so that the upper face of the collar 81 engages the lower end of the switch operating rod 80, thus rendering the connection between the member 2O and the rod 8O virtually solid. The further upward movement of the rod 2O is therefore arrested but the operator through this rigid connection applies a pressure to set the weld while the welding circuit is cle-energized and while the weld is cooling.

The tension on the spring 48 may be regulated by a. wheel 49 which is screw-threaded onto the downwardly extending portion of the operating rod 8O in the yoke 43. The compression on the spring 48 determines the pressure on the work during the welding operation.

The effective length of the link 24 may be changed by loosening the lock nut 5() and turning the rod 24, which is provided with a right hand thread on one end and left hand on the other. Thismeans controls the position of the treadle 29 for a given range of movement of the electrode 37. If it is desired to change the stroke or range of operation of the treadle 29, thereby increasing or decreasing pressure developed by pressing on treadle 29, this may bedone by moving the rod 25 upwardly or downwardly in its socket 26.

In Figures 4 to 11, inclusive, I have illustrated means whereby the electrode 37 may be operated by power means instead of by the foot of the operator. This means comprises a motor 51 upon the end of which is placed a worm 52 as shown in Fig. 7. This worm engages a worm wheel 53 shown in Fig. 6 which is connected to a shaft 54 carrying at one end a gear 55 which meshes with a gear 56 on a shaft 57. These gears may be removed and other gears substituted so as to change the ratio of rotation between shafts 54 and 57. On the other end of the shaft 57 is a gear 58 which meshes with a gear 59 which is loosely mounted on the shaft 54. This gear is also connected with one member 60 of the clutch (see Fig. 8). The other member 61 of the clutch is connected with an eccentric 62 which rotates with the member 61. A lever 62:L is rigidly connected with a sleeve 64 which is loosely mounted on the shaft 57 A second lever 65 (see Fig. 4) is fastened to the sleeve 64 and is connected to a connector 66 which, in turn, is connected to a lever 67 fastened on to the shaft 22 which shaft carries the link 21 which is connected to the lower end 20 of the automatic switch 4.

The clutch comprises the gear 59, the member 60 which rotates therewith. and the driven member 63. The member 63 at that portion which is surrounded by the member 60 is cut away to form spaces in which are placed rollers 68. A roller cage 69 surrounds the member 63 and is provided with slots to accommodate the rollers 68. lVhen the parts are in the relative positions shown in Figures 8 to 11, the rollers are free and the clutch is disconnected. The position of the rollers is controlled by the roller cage 69. This cage has a projection 7 0 adapted to be engaged by a latch 71 which is loosely mounted on the shaft 54. In this position the spring 72 which aids in t-he control of the rollers is under compression and the rollers are free. lVhen it isvdesired to engage the clutch, the member '73, (see Fig. 7) is moved to the left, by a treadle or other suitable means and the lever 74, which is pivoted at 75, engages a pin 76 and presses it inwardly thus removing the latch 71 from the projection on the roller cage 69. This releases the spring 72 which moves the rollers into such a position that they jam between the ilo members 68 and 69 thus locking those two members together and causing the eccentric 62 to rotate. This raises the lower end 20 of the automatic switch, whereupon the same cycle is carried out as with the downward movement ot the treadle Q9. As soon as the treadle or other operating member releases the member 73, a spring 77 causes the latch 7l to engage the projection 70 on the member 69 and the clutch is disconnected.

My invention has many advantages. among which may be mentioned that the switch travels with the operating system until the points stop against the Work, whereupon the welding current is automatically turned on and a predetermined pressure maintained until the welding is completed; the electrical contact between the secondary and the movable electrode is separate from the mechanical connection of the rocker arm to the pedestal with the result that both connections are superior to a connection embodying both features; the transformer and operating parts are placed in a separable pan and are removable from the pedestal as a unit, thus facilitating inspection, repairs, and desired changes; means are provided for adjusting the movement of the treadle and also for adjusting the position ot its range of movement; motor driven means are provided for operating the welding electrodes; special means are provided in the construction ot' the electrode holders whereby a more perfect and a more durable connection is secured; and the insulation of the movable electrode from the pedestal is accomplished by a single washer and a single bushing thus providing the simplest kind of insulating material, While effecting perfect electrical insulation.

Many other changes will be apparent to those skilled in the art.

Many detail changes may be made in the various parts without departing from the spirit ot my invention.

I claim l. In a spot Welder the combination of -a pedestal, an electrode holder pivotally mounted thereon, a transformer, an autocoil and a frame structure carrying said transformer and coil and removable as a unit from said pedestal together with' said electrode holder.

2. In a spot Welder the combination of a frame or pedestal, a yoke pivotally mounted in said pedestal, a rocker arm attached to said yoke and an electrode holder clamped between said yoke and rocker arm.

3. In a spot Welder the combination ot a frame or pedestal, a yoke pivotally mounted on said pedestal, a rocker arm attached to said yoke and an electrode holder clamped between said yoke and rocker arm, and insulating material separating said electrode holder from said'arm and yoke.'

fl. ln a spot Welder the combination of a :trame or pedestal, a yoke pivotally mounted on said pedestal, a rocker arm attached to said yoke, an electrode holder clamped between said yoke and arm and an electrode held in the end of said holder.

5. An electric current controlling and pressure-applying device for a welding machine, comprising a yoke having a boX at one end, a coupling rod extending through said boX having a head, a compression spring sleeved upon said rod in engagement with said yoke, electric switch elementsv carried by said yoke and head and operatively dependent upon the yielding movement therebetween.

(t. In a spot welder, the combination of a movable electrode holder, a work support, means for operating said holder toward said support, compressible means functionally connecting said operating meansvwith said holder and an automatic switch in said connection and which in the normal welding operation and responsive to said compressible means, compels first putting initial pressure at the point of weld, then energizing the welding circuit and then de-energizing said circuit prior to the release of pressure.

7. ln a spot Welder, the combination of a movable electrode holder, a work support, means for operating said holder toward said support, compressible means functionally connecting said operating means with said holder and an automatic switch in said connection and which in the normal welding operation and responsive to said compressible means, compels iirst putting initial pressure at the point of weld, then energizing the welding circuit and then de-energizing said circuit prior to the release ot' pressure while moving the operating means in the same direction.

8. ln a spotwelder, the combination ot a movable electrode holder, a work support, means toroperating said holder to ward said support, compressible means functionally` connecting said operating means with said holder and an automatic switch in said connection and which in the normal welding operation and responsive to said compressible means, compels first putting initial pressure at the point of weld, then energizing the welding circuit and then cle-energizing said circuit prior to the release of pressure and means for increasing the pressure at the point of weld to set the weld after the current is reduced below the welding value.

9. ln a spot Welder, the combination ot a pivoted electrode holder, a work support, means for operating said holder toward said support, means functionally connecting said operating means with said holder for operating the same, and an automatic switch in said connection which in the normal welding operation and responsive to said connecting means, compels tirst putting initial pressure atthe point ot weld, then energizing the welding circuit, then cle-energizing said circuit prior to the release of pressure, and adjustable means in said connection by which more or less initial pressure between the electrodes may be produced before passing the welding current through the work.

l0. In a spot Welder, the combination of a pivoted electrode, a work support, a treadle mechanism for oscillating said electrode toward said support, a connection between said electrode and treadle mechanism, a compression spring and an automatic switch in said connection through which pressure from said treadle mechanism is transmitted to work between said electrode and support and by which the welding circuit is made and broken without relieving the pressure between the electrode and work, and means for adjusting the compression of said spring to vary the pressure exerted by said electrode.

11. In a spot Welder, the combination of a pivoted electrode holder, a work support, a treadle for operating the holder toward said support to bring the electrode in connection with the work and create a pressure therebetween, a connection between said treadle and said holder, an automatic switch, a compressible member in said connection which switch in the normal welding operation and responsive yto said compressible means, compels first putting initial pressure at the point of weld, then energizing the welding circuit, then deenergizing said circuit prior to the release of pressure.

12. An electric welding machine, comprising a welding electrode, a work support, means including a connection adapted to press said electrode into engagement with the work on said support, either with a yielding or positive pressure, an electric switch in and forming a part of said connection, means automatically effective after said electrode engages the work to cause said switch to turn yon the electric current, said last metioned means being adapted to apply pressure between said'electrode and work with yielding eiect initially and positive ett'ect finally, and a tripping device for said switch adapted to cut off the electric current during the application of yielding pressure immediately prior to the application of positive pressure.

13. In an electric welding apparatus, the combination of a movable electrode, a Work support, operating means for moving said electrode into welding position with respect to work on said support, resilientmeans in said operating means and a switch in and forming a part of said operating means for controlling the application and removal of the welding current, said switch beingvrendered operative after contact ofsaid electrode with the work and upon the functioning of'said resilient means.

14. In a spot Welder, the combination of a pivoted electrode holder, a work support, means for operating said holder toward said trode with the work and upon the functioning of said resilient means to control the application and removal of the Welding current.

EDMUND J. VON HENKE.

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