US2908803A

US2908803A - Electric resistance welder

Info

Publication number: US2908803A
Application number: US654190A
Authority: US
Inventors: Arthur L Williams; James F Deffenbaugh
Original assignee: FED MACHINE AND WELDER Co
Current assignee: FED MACHINE AND WELDER Co; FEDERAL MACHINE AND WELDER Co
Priority date: 1957-04-22
Filing date: 1957-04-22
Publication date: 1959-10-13
Anticipated expiration: 1976-10-13

Description

A. L. WILLIAMS ET AL 2,908,803

ELECTRIC RESISTANCE WELDER Oct. 13, 1959 Filed April 22, 1957 3 Sheets-Sheet 1 J6 g INVENTORS Z1 35 7 ARTHUR L.W\\ \AMs BY JAME$ F. DEFF NBAUGH A rrore/ve y Oct. '13, 1959 Y A. L. WILLIAMS ETAL 2,908,803

ELECTRIC RESISTANCE WELDER Filed April 22. 1957 s Sheets-Sheet 2 44 4 J! 45 v I! E-\ ;\3. I

J2 J2 ,g 46

INVENTOR ARTHUR L\W\LUAM5 yJAMzs F. DEFFENBAUGH A. 1.. WILLIAMS ETAL 2,908,803

ELECTRIC RESISTANCE WELDER 3- Sheets-Sheet 3 Filed April 22, 1957 INVENTORS RTHUR L.W\ LLIAMS BY JAMEs F DEFFENBAUGH A 77ORNX United States Patent C) ELECTRIC RESISTANCE WELDER Arthur L. Williams and James F. Detrenbaugh, Warren, Ohio, assignors to The Federal Machine and Welder Company, Warren, Ohio Application April 22, 1957, Serial No. 654,190

. 14 Claims. (Cl. 219-84) Our invention relates to electric resistance welders, particularly to seam welders, and the principal object of our invention is to provide new and improved welders of this character.

In seam welder construction, it is necessary to conduct a current of high amperage from the secondary of the welder transformer to the wheel electrodes in as efficient .manner as possible. The problem is of considerable magnitude since each wheel electrode is carried by a shaft which is journalled in an arm carried by the Welder frame and the arms are respectively electrically connected to opposite sides of the transformer secondary.

For eflicient operation, the means for conducting current from an arm to a respective shaft must provide for the least amount of resistance to the passage of current, not only to minimize the generation of heat caused by the resistance to current flow, but also to minimize the reduction of current caused by resistance in its path of flow. At the same time, it is necessary that the current conducting means does not establish a serious drag on the shaft to prevent its relatively free rotation.

In the past, certain constructions have attempted to solve one or the other of the problems above noted, but none has solved all of the problems in the efficient manner hereinafter disclosed.

Our invention also provides means for adjusting the electrode wheels relative to each other whereby certain machining accuracy heretofore required is eliminated. The adjustment means of our invention enables the electrode wheels to be adjusted not only in an axial direction but also in a radial direction whereby for certain operations the wheels may be relatively skewed to effect better welding conditions.

In the drawings accompanying this specification and forming a part of this application, there is shown, for purposes of illustration, an embodiment which our invention may assume, and in these drawings:

Figure 1 is a small scale, generally schematic representation of a seam welder incorporating our invention,

- Figure 2 is an enlarged sectional view through the upper arm of the welder shown in Figure 1, parts being shown in elevation and parts being only fragmentarily shown,

Figure 3 is an enlarged sectional View corresponding generally to the line 3-3 of Figure 2,

Figure 4 is a fragmentary sectional view corresponding generally to the line 44 of Figure 3,

Figure 5 is a fragmentary sectional view of parts of the upper arm providing for relative adjustment of the wheel electrodes, certain parts being shown fragmentary and in elevation,

Figure 6 is a fragmentary sectional view corresponding generally to the line 6--6 of Figure 5,

Figure 7 is a sectional view corresponding generally to the line 77 of Figure 5,

Figure 8 is a separated perspective view of parts of the construction shown in Figures 5 through 7, and

Figure 9 is a schematic representation of the wheel electrodes in skewed relation.

Patented Oct. 13, 1959 The seam welder disclosed in Figure 1 may be of any standard type comprising a frame 10 housing a transformer 11 in any suitable manner. As is usual, the primary winding 12 of the transformer is adapted to be connected to a source of electrical energy and the opposite ends of the secondary 14 are respectively connected to upper and

lower arms

15 and 16 of the welder.

Each

arm

15 and 16 rotatably supports a shaft and the shafts carry the seam welding wheels 17 between which work is to be welded. The lower arm 16 usually extends horizontally in fixed manner from the welder frame, as seen in Figure 1, while the upper arm 15 is mounted for vertical movement toward and away from the lower arm. Movement of the upper arm away from the lower arm provides clearance between the

wheel electrodes

17, 17 for the insertion of the work to be welded, and movement of the upper arm toward the lower arm provides for firm engagement of the wheel electrodes with opposite sides of the work to be welded.

The upper arm may be moved in any suitable manner, a common one including a vertical slide 18 connected to said arm and slidably received in a bearing 19 carried by the frame 10. A fluid motor 20 provides the power for moving the upper arm. In the present disclosure, only the upper arm 15 is shown in detail but it will be appre ciated that our invention may also be used in connection with the lower arm.

The upper arm 15, in the present embodiment, comprises a housing 21 having a welled upper portion 22 which may have suitable connection to the slide 18. The well of the portion 22 may be closed by a cover 23 so that cooling water may be circulated therethrough by means of pipe connections 24. A horizontal shaft 25 is journalled within the housing 21, the forward end of the shaft carrying the wheel electrode 17 and the rear portion of the shaft extending outwardly of the housing, as shown.

The housing has internal

annular surfaces

26, 27 into which respectively seat roller bearings 28, 329. Insulating sleeves 30 are disposed between the bearings and the housing so that no electrical current will be transmitted through the bearings to cause deleterious pitting thereof.

The

bearing seats

26, 27 have oppositely disposed

shoulders

31, 32 respectively and the shaft 25 has an annular shoulder 33 engaging with the inner race of the bearing 28. Play in the

bearings

28, 29 may accordingly be adjusted by means of a ring-type nut 34 which is threaded on the shaft 25. The weld wheel 17 is secured to the outer end of the shaft 25 in any suitable manner and the shaft and wheel may be water cooled in accordance with customary practice.

The shaft 25 may be driven in any suitable manner and, as herein shown, a worm wheel 35 is keyed to the shaft and a ring-type nut 36 is threaded onto the shaft to hold the wheel against a shaft shoulder 37. A worm 38 carried by a shaft 39 journalled in the housing 21, meshes with the worm wheel 35. An electric motor, not shown, may be used to rotate the worm shaft 39.

A sub-housing 40 is connected in axial alignment to the rear end of the housing 21, as by means of bolts 41 to provide good mechanical and electrical connection therebetween. The

housings

21 and 40 are made of good current conducting metal, such as cast copper or copper alloy, and likewise the shaft 25 and weld wheel 17 are also made of good current conducting metals which will suitably take the pressure necessary in a Welding operation. Suitable copper alloys may be used for the shaft and weld wheel. Likewise, the saddle 42 carried by the lower end of the slide 18 and to which the housing 21 is securely mechanically and electrically connected is also made of suitable metal such as cast copper or copper alloy. Accordingly, a low resistance path is established for conducting electrical current from the transformer secondary, through the saddle 42, housing 21 and to the sub-housing 40.

Means are herein provided for efliciently conducting electrical current from the arm (housing 21 and sub housing 40) to the shaft 25 and weld wheel 17. In the embodiment of our invention herein disclosed, a plurality of 'current conducting means 43 are radially spaced about the shaft 25 and disposed in spaces 44 between the shaft and the sub-housing 40.

Each of said current conducting means is best illustrated in Figures 3 and 4 and preferably comprises a flexible member 45 having one end mechanically and electrically secured to the sub-housing 40 and an opposite end free for flexing movement toward the shaft 25.

The flexible member may be formed of any suitable flexible conductor material, such as braided wire or ribbon, or the like, although at the present time it is preferred to form the member of stacked copper laminations.- As an example, laminations of hard copper, each .005 inch, have been successfully used. The lami nations are preferably rectangular, to form an oblong member 45, and each member is spaced laterally from the shaft and extends generally parallel or lengthwise of the shaft. One end of each member is formed with atransverse aperture to pass a bolt 46, the head of the bolt bearing against the innermost lamination and the end of the bolt being threaded into the sub-housing 40 to mechanically and electrically secure the member 45 to the sub-housing 40. A copper spacer collar 47 may be interposed between the outermost lamination and the inner surface of the sub-housing to properly position the member 45 and to enhance electrical conduction.

Each lamination may be silver coated or only the inner and outermost laminations in some instances are silver coated to provide for good electrical connection. The collar 47 may likewise be silver coated, if desired.

A copper shoe 48 is secured to the free end of each flexible member 45 and mechanically and electrically held to such end by means of a machine screw 49. The surface of the shoe which adjoins the member 45 may be silver coated to improve current conduction.

The innner surface of each shoe 48 is provided with a silver liner 50 and the inner surface of the liner is arcuate and generally corresponds to the transverse curvature of the adjacent portion of the shaft 25.

Means are provided for urging the free ends of the flexible members 45 in a. direction toward the shaft and in the present embodiment the sub-housing 40 is formed with a pair of threaded apertures 51 in line with each'free end of the members 45. Socket head plugs 52 are threaded into the apertures 51 to bear against and compress respective coil springs 53. A sheet of insulation 54 is disposed between the coil springs 53 and the adjacent surface of the member 45 to prevent electrical current from passing through the springs and adversely affecting them.

The assembly of the current conducting means 43 with the sub-housing 40 may be made while the latter is removed from the housing 21 and shaft 25. This, therefore, facilitates assembly operations and also provides easily detachable means for the purpose of inspecting the condition of the current conducting means 43 after a considerable period of use.

An end plate 55 may be secured to the rear open end of the sub-housing 40, the plate carrying a seal 56 hearing against the shaft to restrict entrance of foreign matter. A similar seal 57 may be carried by the forward end of the housing 21 to bear aganst the shoulder 33 and restrict entrance of foreign matter at the forward end of the housing.

The current conducting means 43 are preferably ar- 4 In this manner, cocking pressure against the shaft is avoided and the shaft may freely rotate in its bearings. Since a low resistance current path is provided by the current conducting members 43, the exceedingly great pressures heretofore required to maintain good electrical contact are eliminated and very little drag opposes rotation of the shaft.

Our invention also provides means for adjusting the wheel electrodes 17-17 relative to each other and in the presently disclosed embodiment the saddle 42 be,- tween the housing 21 and the slide 18 comprises a weld head support 60 and a lead connection member 61.

The weld head support 60 has a circular upper plane surface 62 and a central boss 63 extending upwardly from such surface. The support 60 is formed with a transverse through bore 64 for passing a bolt 65 and the'boss 63 is formed with a cross slot 66 intersecting the bore 64. The support 60 is also formed With a pluralityof transverse apertures 67 (four in the embodiment disclosed) for passing bolts 68.

The underside of the support 60 is formed with

marginal enlargements

69, 70, the enlargement 70 providing a gib surface 71 which receives a complementary slide surface 72 formed along the side of the upper portion 22 of the housing 21. A similar slide surface 73 is formed along the opposite side of the portion 22 for cooperation with the angular side surface of an elongated key member 74.

The key member is interposed between the slide surface 73 andan inwardly directed shoulder 75 formed on the enlargement 69 and, by means of bolts 76 (one of which is shown in Figure 6) securely locks the housing 21 against sliding movement along the gib surface 71 and the corresponding surface of the key member 74. When the bolts 76 are loosened, the housing 21 may be adjusted along a substantially horizontal plane in a direction defined by the gibsurfaces. It will thus be appreciated that the upper electrode wheel 17 may be adjusted in an axial direction relative to the lower electrode Wheel.

Provision is also made for rotation of the upper electrode wheel in a generally horizontal plane so that misalignment of the wheels may be corrected, or so that the wheels may be disposed in skewed relation, as suggested in Figure 9, for certain welding requirements.

In the present embodiment, the undersurface of the lead connection member 61 is formed with a plane surface 80 complementary to the surface 62 of the weld head support 60. The surface 80 is formed with an annular well 81 for receiving the boss 63, the upper surface of the latter being preferably clear of engagement with the bottom of the Well.

The member 61 is also bored to receive a sleeve 82 having a head 83. The lower end of the sleeve 82is milled to form a key 84 which fits into the cross slot 66 of boss 63 and holds the sleeve against rotation. The bolt 65 is threaded into the sleeve and the parts provide an axis about which the head support 60 may rotate. The lead connection member 61 is formed with arcuate slots 85 for passing the bolts 68. Loosening of the bolts 68 will permit the head support 60 to be swung about its vertical axis an amount defined by, the length of the slots 85. After adjustment, the bolts 68 may be tightened to firmly hold the head support and lead connection 'member is axially adjusted relation.

A'sheet of electrical insulation is interposed between the upper surface of lead connection member 61 and slide 18, and bolts 87 are provided to maintain the member and-slide assembled, insulating sleeves 88 being interposed between the bolts and the member 61. Thus, the member 61 is electrically insulated from the slide. I The slide 18 is of non-circular cross-section and the bearing 19 will accordingly hold the slide and the lead connection member 61 against rotation about the axis provided by the sleeve 82. As best seen in Figure 1, the member 61 has afoot 90 to which one side of the transformer secondary may be connected.

In view of the foregoing, it will be apparent to those skilled in the art that we have accomplished at least the principal object of our invention and it will also be apparent to those skilled in the art that the embodiment herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described, hence it will be appreciated that the herein disclosed embodiment is illustrative only, and that our invention is not limited thereto.

- We claim:

1 1. A resistance Welding machine, comprising a current carrying arm, a current carrying shaft journalled by said arm and providing an electrode wheel, and means providing for current flow between said arm and said shaft and comprising a flexible member having one portionmechanically and electrically connected to said arm and a spaced portion immediately engaging said shaft and yieldably pressed thereagainst.

2. A resistance welding machine, comprising a current carrying arm, a current carrying shaft journalled by said arm and providing an electrode wheel, and means providing for current flow between said arm and said shaft and comprising a flexible laminated member having one portion mechanically and electrically connected to said arm and a spaced portion immediately engaging said shaft and yieldably pressed thereagainst.

3. A resistance welding machine, comprising a current carrying arm, a current carrying shaft journalled by said arm and providing an electrode wheel, and means providing for current flow between said arm and said shaft and comprising a current-conducting member laterally spaced from and disposed generally longitudinally of said shaft, one end of said member being mecha-.

nically and electrically connected to said arm, and means for yieldably pressing the other end of said member in a direction toward said shaft.

4. A resistance welding machine, comprising a current carrying arm, a current carrying shaft journalled by said arm and providing an electrode wheel, and means providing' for current flow between said arm and said shaft and comprising a current-conducting member laterally spaced from and disposed generally longitudinally of said shaft, one end of said member being mechanically and electrically connected to said arm and the Opposite end being free and having an inner arcuate surface generally corresponding to the transverse curvature of said shaft, and means carried by said arm for pressing inwardly against said opposite end of said current conducting member to press said arcuate surface into sliding current conducting engagement with said shaft.

5. A resistance welding machine, comprising a current carrying arm, a current carrying shaft journalled by said arm and providing an electrode wheel, and means providing for current flow between said arm and said shaft and comprising a flexible current conducting member laterally spaced from and disposed generally longitudinally of said shaft, one end of said member being mechanically and electrically connected to said arm and its opposite end being free for flexing movement toward said shaft and having an inner arcuate surface generally corresponding to the transverse curvature of said shaft, and means carried by said arm for pressing inwardly against said opposite end of said current conducting member to press said arcuate surface into sliding current conducting engagement with said shaft.

6. A resistance welding machine, comprising a current carrying arm, a current carrying shaft journalled by said arm and providing an electrode wheel, and means providing for current flow between said arm and said shaft and comprising an elongated flexible member laterally spaced from and disposed generally longitudinally of said shaft, said member being formed of current con- 6 ducting laminations and one end thereof being mechani cally and electrically connected to said arm and the opposite end being free for flexing movement toward said said shaft, a current conducting shoe electrically connected to said opposite end of said member and having an inner arcuate surface generally corresponding to the transverse curvature of said shaft, and means carried by said arm for pressing inwardly against said opposite end of said member to press said arcuate shoe surface into sliding current conducting engagement with said shaft.

7. A resistance welding machine, comprising a current carrying arm, a current carrying shaft journalled by said arm and providing an electrode wheel, and means providing for current flow between said arm and said shaft and comprising a block-like elongated flexible member laterally spaced from and disposed generally longitudinally of said shaft, said member being formed of copper laminations and being silver coated on opposite sides, one end of said member being mechanically and electrically connected to said arm and the opposite end being free for flexing movement toward said shaft, a copper shoe mechanically and electrically connected to said opposite end of said member, the inwardly directed surface of said shoe having a silver lining and the inner surface of the latter having an arcuate surface generally corresponding to the transverse curvature of said arm, a plug threaded through said arm and having its axis intersecting said member at said opposite end, and a coil spring compressed between the inner end of said plug and said opposite end of said member to press inwardly against said opposite end and thereby press said arcuate surface into sliding current conducting engagement with said shaft.

8. A seam welder having a low friction welding wheel mount, comprising a current carrying arm, a current carrying shaft supporting the welding wheel, spaced antifriction bearings between said arm and said shaft, said bearings being electrically insulated to prevent passage of current therethrough, and means providing for current flow between said arm and said shaft comprising a plurality of flexible current conducting members equally spaced apart radially about said shaft and disposed in a space between said arm and said shaft in position spaced laterally of said shaft, each member having one end mechanically and electrically connected to said arm and having its other end free for flexing movement toward said shaft and formed with an inner arcuate surface generally corresponding to the transverse curvature of said shaft, and means carried by said arm for pressing inwardly against said opposite end of said current conducting member to press said arcuate surface into sliding current conducting engagement with said shaft.

9. The construction according to claim 8 and further including said current conducting members in paired opposing relation.

10. A resistance welding machine, comprising a support, a current carrying arm, a current carrying shaft journalled by said arm and providing an electrode wheel, means providing for current flow between said arm and said shaft, said arm having spaced slide surfaces one of which is slidable along a corresponding surface of said support and the other one is slidable along a corresponding surface of a wedge-like key member, and means for urging said key member in a direction to bind said arm against movement relative to said support.

11. In a resistance welding machine having one electrode movable toward and away from another electrode, a mount for the movable electrode, comprising a reciprocable slide member, a lead connection member of current conducting material secured to but insulated from said slide member for reciprocatory movement therewith and having means for connection to one side of the secondary circuit of the welding transformer, a support member of current conducting material connected to said lead connection member for pivotable movement about an axis generally parallel to the axis of reciprocation of said slide member, a casing member of current conducting material connected to said support member for slidable adjustment transverse to the axis of reciprocation of said slide member, a current carrying shaft supporting said one movable electrode and journalled in bearings carried by but insulated from said casing member, and means between said casing member and said shaft for conductin welding current from the former to the latter.

12. In a resistance welding machine having one electrode movable toward and away from another electrode, a mount for the movable electrode comprising a reciprocable slide member, a lead connection member of current conducting material having one side connected to but'insulated from said slide member for reciprocatory movement therewith and having means for connection to one side of the secondary circuit of the welding transformer, a support member of curernt conducting material having. one side bearing against the opposite side of said lead connection member and being connected to the latter for pivotable movement about an axis generally parallel to the axis of reciprocation of said slide member, the opposite side of said support member being formed with spaced guide grooves extending transversely of the axis of reciprocation of said slide member, a casing member of current conducting material having spaced slide surfaces, one of which slidably engages the surface of one of said spaced guide grooves and a wedge-like key member seated between the other of said guide grooves and slide surfaces whereby said casing member is held to said support member for slidable adjustment transverse to the axis of reciprocation of said slide member, means for forcing said wedge-like key member into locking engagement with the surfaces of its associated guide groove and slide surface to hold said support member in adjusted position, a curent carrying shaft supporting said one movable electrode and journalledin bearings carried by but insulated from said casing members, and means between said casing member and said shaft for conducting welding current from the former to the latter.

13. In a resistance welding machine having a rotatable electrode, a current conducting shaft supporting and electrically connected to said electrode, a casing through which said shaft extends and in which said shaft is rotatably supported, said electrode extending from one side of said casing and an end portion of said shaft extending from the opposite side of said casing, an end member of current conducting material removably secured to the opposite side of said casing and having an opening passing said shaft end portion, said end member being connectable to one side of the secondary circuit of the welding transformer, and current transfer means for conductmg Welding current from said end member to said shaft,

said transfer means being carried by said end member and assembleable therewith when said end member is re moved from said casing, said end member and transfer means being assembled as a unit with said casing in cooperable relation with said shaft end portion.

14. In a resistance welding machine having a rotatable electrode, a current conducting shaft supporting and electrically connected to said electrode, a casing through which said shaft extends and in which said shaft is 1'otatably supported, said electrode extending from one side of said casing and an end portion of said shaft extending from the opposite side of said casing, an end member of current conducting material removably secured to the opposite side of said casing and having an opening passing said shaft end portion, said end member being connectable to one side of the secondary circuit of the welding transformer, and current transfer means for conducting welding current from said end member to said shaft, said current transfer means including a plurality of similar flexible current conducting members spaced from each other and grouped about the axis of said end member opening, each conducting member having one end mechanically and electrically connected to said end member and its opposite free end pressed into sliding electrical engagement with said shaft end portion, said current conducting members being assembleable with said end memher when the latter is removed from said casing and said end member and conductor members being assembled as a unit with said casing in cooperable relation with said shaft end portion.

References Cited in the file of this patent UNITED STATES PATENTS 1,045,911 Thomson Dec. 3, 1912 1,199,408 Muller Sept. 26, 1916 1,778,628 Eckman Oct. 14, 1930 1,787,115 Lewis Dec. 30, 1934 2,200,112 Gilbert May 7, 1940 2,276,925 Caputo Mar. 17, 1942 2,389,034 Eisler Nov. 13, 1945 2,529,634 Sciaky Nov. 14, 1950 2,636,066 Sciaky Apr. 21,1953 2,710,327 Powley June 7, 1955 2,726,371 Seeloff Dec. 6, 1955 2,730,600 Fisher et al Jan. 10, 1956