CA1214523A - Resistance welding electrode holders - Google Patents
Resistance welding electrode holdersInfo
- Publication number
- CA1214523A CA1214523A CA000468228A CA468228A CA1214523A CA 1214523 A CA1214523 A CA 1214523A CA 000468228 A CA000468228 A CA 000468228A CA 468228 A CA468228 A CA 468228A CA 1214523 A CA1214523 A CA 1214523A
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- Prior art keywords
- electrode holder
- pivotal
- electrode
- elements
- welding apparatus
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
Resistance welding apparatus with a compound electrode holder is provided. The apparatus is more effective in re-sistance welding members of U-shaped cross section than appara-tus heretofore known. The compound electrode holder enables its electrode to travel in one arcuate path throughout most of its travel or stroke and to move in a second arcuate path as it approaches the workpiece. The compound electrode holder achieves a large path of travel of its electrode and at the same time accurate alignment of the electrodes and reliable welds are attained.
Resistance welding apparatus with a compound electrode holder is provided. The apparatus is more effective in re-sistance welding members of U-shaped cross section than appara-tus heretofore known. The compound electrode holder enables its electrode to travel in one arcuate path throughout most of its travel or stroke and to move in a second arcuate path as it approaches the workpiece. The compound electrode holder achieves a large path of travel of its electrode and at the same time accurate alignment of the electrodes and reliable welds are attained.
Description
This invention relates to resistance welding apparatus hazing a compound electrode holder.
Il~hen electrodes have required long travel or strokes, such as when welding members of deep IJ-shaped cross section, "C" type holders heretofore have generally been used. These require considerable height to accommodate the length of travel, and also considerable size and weight to accomplish proper rigidity for accurate electrode alignment. The "C"
type electrode holders also have required long laminated shunts or cables to accommodate stroke length and these have a tendency to self destruct due to the inductive kick. The long shunts or cables also produce large secondary loops no-suiting in large electrical losses. Consequently, a meekly larger transformer is required and poor weld quality also no-suits due to the fact that the secondary loop varies since the shunt or cable never bends exactly the same from weld to weld.
Scissors-type electrode holders have not been satisfac-tory for welding members of deep U-shaped cross section be-cause the arcuate path ox the electrodes is insufficient to clear the members to be welded so that the welded member can be moved and a new member to be welded can be placed in weld-in position. If the scissors-type electrode holders are sufficiently long, a desired path of travel may be obtained, but then many of the same disadvantages encountered with C-type electrode holders again result.
A compound electrode holder in accordance with the invent lion enables an electrode held thereby to move in one arcuate path through most of the travel of the electrode and to move in a second arcuate path as the electrode approaches the worn-piece. The center of the second arcuate path is on a line
Il~hen electrodes have required long travel or strokes, such as when welding members of deep IJ-shaped cross section, "C" type holders heretofore have generally been used. These require considerable height to accommodate the length of travel, and also considerable size and weight to accomplish proper rigidity for accurate electrode alignment. The "C"
type electrode holders also have required long laminated shunts or cables to accommodate stroke length and these have a tendency to self destruct due to the inductive kick. The long shunts or cables also produce large secondary loops no-suiting in large electrical losses. Consequently, a meekly larger transformer is required and poor weld quality also no-suits due to the fact that the secondary loop varies since the shunt or cable never bends exactly the same from weld to weld.
Scissors-type electrode holders have not been satisfac-tory for welding members of deep U-shaped cross section be-cause the arcuate path ox the electrodes is insufficient to clear the members to be welded so that the welded member can be moved and a new member to be welded can be placed in weld-in position. If the scissors-type electrode holders are sufficiently long, a desired path of travel may be obtained, but then many of the same disadvantages encountered with C-type electrode holders again result.
A compound electrode holder in accordance with the invent lion enables an electrode held thereby to move in one arcuate path through most of the travel of the electrode and to move in a second arcuate path as the electrode approaches the worn-piece. The center of the second arcuate path is on a line
-2- ~,~
so substantially perpendicular Jo the axes o-f the electrodes wren engaging the l~orkpiece and the line symmetrically extends be-tweet the electrode tips to assure that the electrodes move substantially coccal when engaging the workups. The center of the second arcuate path is also the center of any arcuate movement of the other electrode holder. This assures precise alignment of the electrodes as whey engage the workups under high pressure.
The compound electrode holder with the two arcuate paths I enables the apparatus to consume less height and to be sub Stan-tidally lighter in weight than those heretofore known, so that the apparatus can have a degree of portability. The design of the apparatus also enables laminated shunts or cables to be short. The travel path of the electrode holders and the en-vironment are also known, as determined by the apparatus design, which results in the position, type of loop, length, and proxy amity to magnetic materials, all of which affect the reactance and impedance of the secondary loop, to be known. Thus, the amount of electrical energy supplied at the primary end of the welding supply or transformer for a given amount of power a the electrodes can be determined. Lower secondary voltage can be used to achieve the same secondary current as with the pro-virus apparatus. The use of lower secondary voltage also no-dupes or eliminates expulsion material being welded or portions of the electrodes being blown away by excess voltage at the start of the resistance weld.
It is, therefore, a principal object of the invention to provide resistance welding apparatus with a compound electrode holder capable of effectively welding work pieces requiring a I long electrode travel or stroke.
So Another object of the invention is to provide resistance welding apparatus capable of effectively welding work pieces having deep IJ-shaped cross sections.
A further object of the invention is to provide nests-lance welding apparatus with a compound electrode holder have in a large radius stroke and a shorter radius stroke, the latter being located on a center which is on a line perpendi-cuter to the axes of the electrodes when substantially engaged Whitehall the workups and symmetrically extending between the tips in of the electrodes when so engaged.
any other objects and advantages of the invention will be apparent from the following detailed description of a pro-furred embodiment thereof, reference being made to the accom-paying drawings, in which:
Fig. 1 is a fragmentary, side view in elevation of welding apparatus embodying the invention, in a welding position;
it. 2 is a fragmentary side view in elevation similar to Fig. 1, but with the welding apparatus in a retracted position;
Fig. 3 is a view in section taken along the line 3-3 of Fig. l; and Fix. 4 is a diagrammatic view showing two arcuate paths of movement of an electrode carried by a compound welding electrode of the apparatus.
Referring to the drawings and particularly to Fix. l, welding apparatus according Jo the invention is indicated at 10 and includes a power supply shown in the Norm of a trays-former 12 having an input end 14 and an output end 16. The output end 16 has a lower terminal block 18 and an upper terminal block on. The terminal blocks have threaded holes therein by means of which electrode holders or shunts can be mounted on the terminal locks by machine screws. The trays-former is shown in more Doyle in my U. S. Patent No. 4,525,-618, issued on June 25, 1985, and will not be discussed in further detail. Other power supplies can be employed but the transformer 12 has the advantage of providing some degree of portability and compactness for the overall welding apparatus.
The welding apparatus 10 includes a lower electrode holder 22 and a upper, compound electrode holder 24. The lower elect trove holder 22 his a long, heavy shank 26, to a rear end of which is af~lxed an electrical connector preferably in the o'er a a laminated shunt 28. The other end of the shunt 28 is electrically connected to the terminal block 18, with both ends affixed by machine screws or the like (not shown). The shunt enables same moveT,Ient of the electrode holder 22 but at the save time it is short Jo minimize secondary losses. The outer end of the shank 26 ox the electrode holder 22 carries an electrode pa extending upwardly therefrom.
A main supporting frame 32 extends upwardly from the lower electrode holder 22 at an intermediate portion thereof.
The supporting frame 32 includes two spaced side legs 34 and 36, lower ends of which extend on each side ox the shank 26 of Tyler' electrode Hollywood 22. A transverse web extends between the legs 34 and 36 above the shank 26, as jest seen in Fig. 3. A clamping plate 40 is fastened to the lower ends of the legs, 34 and 36 by machine screws 42 and clamps the frame 32 securely on the lower holler 22 with insulating pads 44 and 46 surrounding the holder. Upper end portions of the legs 34 and 36 are connected by a tie bar or rod 48.
Jo I
The supporting frame 32 is pivotal supported by the transformer 12 through a bracket 50. The bracket 50 has side arms 52 and 54 with inwardly extending flanges 56 and 58 fig. 3) which are also mounted on the lower terminal block 18 by ma chine screws (not shown). A tie bar or rod 59 extends between the arms. The frame legs 34 and 36 have intermediate portions pivotal connected to outer end portions of the bracket arms 52 and 54 by pivot pins 60 and 62 which are retained by suit-able clips 64, Insulating washers 66 are located between the frame legs 34 and 36 and the bracket arms 52 and 54.
The pivot axes of the pivot pins 60 and 62 are precisely located so that they are on a line perpendicular to the axes of the electrodes and which extends symmetrically through the space between tips of the electrodes when they are engaged with the workups. This assures that DIOVement of the electrodes will have their axes substantially perpendicular to the work-piece to be welded when engaged with the workups.
The compound electrode holder 24 includes a first element 68 and a second element on. The element 68 has two side plates 72 and 74, upper portions of which are connected by a tie bar or rod 76. The upper ends of the side plates 72 and 74 are connected by a pivot pin 78 to the frame legs 34 and 36 at a position above the pivot pins 60 and 62 and to the rear there-of, near the terminal block 20 of the transformer 12. Lower ends of the side plates 72 and 74 have flat stops 80 and 82 which engage raised stop surfaces 84 and 86 on the transverse web 38 when the element 68 is in its lowest pivotal position.
Lower ends of the first element 68 are pivotal connected by a pivot pin 88 to a lower enlarged end 90 of the second I holder element 70 with insulating bushings 91 there between.
The pivot pin 88 is positioned such that it is coaxial with the axes of the pins 6Q and 62 when the stops 80 and 82 engage the stop surfaces 84 and 86. Further pivotal movement of the second element on toward the first electrode holder 22 is then in an arcuate path having the same radius and center as the electrode holder 22. An outer, upper end 92 of the holder element 70 carries a long electrode 94. Like the axes of the pivot pins 60 and I the axis of the pivot pin 88 is on a line substantially perpendicular Jo the axes of the electrodes when engaged with the workups and the line also symmetrically extends through the space between tips of the electrodes.
An intermediate portion of the element 70 has outwardly extending ears 96 and 98 carrying insulating stops 100 and 102 which project reawardly from the ears. The stops engage pro-jetting tabs 104 and 106 on intermediate portions of the side plates 72 and 74 of the first element 68 when the second eye-mint 70 is raised, so that the first and second elements 68 and 70 then move as a unit. The electrode 94 then travels in an arcuate path Whitehall a radius having its center at the axis of the pivot pin 78.
Springs 108 and 110 are connected between the first and second elements 68 and 70 specifically between the projecting tabs 104 and 106 and intermediate portions of the element 70.
When the second element on is then moved toward the first elect trove holder 22, as from the position of jig. 2 toward the position of jig. 1, the two elements 68 and 70 move as a unit until the stops 80 and 82 engage the stop surfaces 84 and 86.
The element 68 then remains stationary while the element 70 moves further toward the electrode holder 22 as the electrode 94 nears and then engages the workups. At this time, the path of the electrode 94 is on a radius having its center a the axis of the pivot pin 88 which is also the axes of the pivot pins I and 62. This assures that the axes of the electrodes 30 and 94 are substantially perpendicular Jo the surfaces of the workups Jo be welded and move on a common arcuate path. The electrodes thereby engage the workups on a common axis and there is no tendency for the tips of the electrode Jo push or pull relative Jo the workups as can occur if the elect troves move about separate centers or a center which is other in than on a line perpendicular to the electrode axes and sum-metrical with respect to the space between the tips of the electrodes.
The second element 70 has a rearwardly-extending project-in block 112 to which power is supplied by a second laminated shunt 114. One end of the shunt 114 is electrically connected to the block 112 by machine screws (not shown) and the other end of the shunt is connected to the terminal block 20 by similar machine screws or the like. The shunt 114 is located near the pivot pin 78 so that minimal flexing movement of the shunt 114 occurs as the compound electrode holder 24 moves between its extreme positions of Pigs. 1 and 2. Like the shunt 28, the shunt 114 is short to minimize secondary electrical losses.
The compound electrode holder 24 can be moved by various means. However, a fluid-operated cylinder and specifically a pressure intensifier cylinder 116 is preferred. The pressure intensifier cylinder can be of the type shown in my U. S. Patent 4,135,076 issued January 16, 1979, and will not be discussed in detail The rod end of the cylinder is pivotal connected I to upper ends of the main frame lets 34 and 36 by pivot pins 118 and 120. A piston rod 122 has its outer end pivotal connect ted to ears 124 by a pivot pin 126, the ears being separated by a groove 128 in the second element 70.
'hen the compound electrode holder 24 is in its maximum raised pivotal position, there is ample room between the elect troves 30 and 94 for a workups to be placed in welding position.
This includes work pieces having deep Shaped cross-sectional shapes. when the piston rod 122 is extended and the compound electrode holder 24 moves toward the electrode holder 22, the n elements 68 and 70 move together with the electrode 94 pivoting in an arcuate path around the pivot pin 78 (see jig. 4). When the stops on and 82 engage the stop surfaces 84 and 86, further extension of the piston rod 122 then causes the electrode 94 to move in a shorter arcuate pettily with the center being at the axis of the pivot pin 88. Any movement of the electrode 30 likewise is in an arcuate path having a center at the axes of the pivot pins I and 62 which are coaxial with the axis of the pivot pin 88. Thus, as the electrodes 30 and 94 are near the workups and continue movement to engage the workups, the 2 n movement is on a common arcuate path with the center of the path being on a line substantially perpendicular to the axes of the electrodes and extending symmetrically through the space between the electrode tips so that the electrodes engage the workhouse with their axes substantially perpendicular thereof.
Thus 9 the high pressure of the electrodes on the workups is substantially perpendicular to the workups so that there is no pushing or pulling of the electrodes relative to the workups.
The large radius of the path or stroke of the electrode I throughout most of its length enables the electrode 94 to clear a workups which could not be achieved in many instances I
if the electrode I were moved solely through an arcuate path having its center at the axis of the pivot pin 88. Further, the arcuate path of the electrode holder 24 enables the overall height of the apparatus to be substantially less than with the C-type electrode holders heretofore used. The arcuate path also enables the shunts or cables to be shorter, reduce in the tendency to self-destruct due to inductive kick.
The shorter cables also produce shorter secondary loops no-suiting in less electrical losses. The smaller electrical losses enable smaller transformers or other power sources to be employed. lulled quality is also improved since the movement or bend of the shunt or cable is less and minimal variation in the losses in the secondary loop results. Since a smaller power source and less electrical energy are needed and lower secondary voltage can be used, expulsion is also reduced or eliminated. Expulsion occurs when some of the metal or mater-tat being wended or portions of the electrodes are blown away by excess voltage at the beginning of the resistance welding cycle.
so substantially perpendicular Jo the axes o-f the electrodes wren engaging the l~orkpiece and the line symmetrically extends be-tweet the electrode tips to assure that the electrodes move substantially coccal when engaging the workups. The center of the second arcuate path is also the center of any arcuate movement of the other electrode holder. This assures precise alignment of the electrodes as whey engage the workups under high pressure.
The compound electrode holder with the two arcuate paths I enables the apparatus to consume less height and to be sub Stan-tidally lighter in weight than those heretofore known, so that the apparatus can have a degree of portability. The design of the apparatus also enables laminated shunts or cables to be short. The travel path of the electrode holders and the en-vironment are also known, as determined by the apparatus design, which results in the position, type of loop, length, and proxy amity to magnetic materials, all of which affect the reactance and impedance of the secondary loop, to be known. Thus, the amount of electrical energy supplied at the primary end of the welding supply or transformer for a given amount of power a the electrodes can be determined. Lower secondary voltage can be used to achieve the same secondary current as with the pro-virus apparatus. The use of lower secondary voltage also no-dupes or eliminates expulsion material being welded or portions of the electrodes being blown away by excess voltage at the start of the resistance weld.
It is, therefore, a principal object of the invention to provide resistance welding apparatus with a compound electrode holder capable of effectively welding work pieces requiring a I long electrode travel or stroke.
So Another object of the invention is to provide resistance welding apparatus capable of effectively welding work pieces having deep IJ-shaped cross sections.
A further object of the invention is to provide nests-lance welding apparatus with a compound electrode holder have in a large radius stroke and a shorter radius stroke, the latter being located on a center which is on a line perpendi-cuter to the axes of the electrodes when substantially engaged Whitehall the workups and symmetrically extending between the tips in of the electrodes when so engaged.
any other objects and advantages of the invention will be apparent from the following detailed description of a pro-furred embodiment thereof, reference being made to the accom-paying drawings, in which:
Fig. 1 is a fragmentary, side view in elevation of welding apparatus embodying the invention, in a welding position;
it. 2 is a fragmentary side view in elevation similar to Fig. 1, but with the welding apparatus in a retracted position;
Fig. 3 is a view in section taken along the line 3-3 of Fig. l; and Fix. 4 is a diagrammatic view showing two arcuate paths of movement of an electrode carried by a compound welding electrode of the apparatus.
Referring to the drawings and particularly to Fix. l, welding apparatus according Jo the invention is indicated at 10 and includes a power supply shown in the Norm of a trays-former 12 having an input end 14 and an output end 16. The output end 16 has a lower terminal block 18 and an upper terminal block on. The terminal blocks have threaded holes therein by means of which electrode holders or shunts can be mounted on the terminal locks by machine screws. The trays-former is shown in more Doyle in my U. S. Patent No. 4,525,-618, issued on June 25, 1985, and will not be discussed in further detail. Other power supplies can be employed but the transformer 12 has the advantage of providing some degree of portability and compactness for the overall welding apparatus.
The welding apparatus 10 includes a lower electrode holder 22 and a upper, compound electrode holder 24. The lower elect trove holder 22 his a long, heavy shank 26, to a rear end of which is af~lxed an electrical connector preferably in the o'er a a laminated shunt 28. The other end of the shunt 28 is electrically connected to the terminal block 18, with both ends affixed by machine screws or the like (not shown). The shunt enables same moveT,Ient of the electrode holder 22 but at the save time it is short Jo minimize secondary losses. The outer end of the shank 26 ox the electrode holder 22 carries an electrode pa extending upwardly therefrom.
A main supporting frame 32 extends upwardly from the lower electrode holder 22 at an intermediate portion thereof.
The supporting frame 32 includes two spaced side legs 34 and 36, lower ends of which extend on each side ox the shank 26 of Tyler' electrode Hollywood 22. A transverse web extends between the legs 34 and 36 above the shank 26, as jest seen in Fig. 3. A clamping plate 40 is fastened to the lower ends of the legs, 34 and 36 by machine screws 42 and clamps the frame 32 securely on the lower holler 22 with insulating pads 44 and 46 surrounding the holder. Upper end portions of the legs 34 and 36 are connected by a tie bar or rod 48.
Jo I
The supporting frame 32 is pivotal supported by the transformer 12 through a bracket 50. The bracket 50 has side arms 52 and 54 with inwardly extending flanges 56 and 58 fig. 3) which are also mounted on the lower terminal block 18 by ma chine screws (not shown). A tie bar or rod 59 extends between the arms. The frame legs 34 and 36 have intermediate portions pivotal connected to outer end portions of the bracket arms 52 and 54 by pivot pins 60 and 62 which are retained by suit-able clips 64, Insulating washers 66 are located between the frame legs 34 and 36 and the bracket arms 52 and 54.
The pivot axes of the pivot pins 60 and 62 are precisely located so that they are on a line perpendicular to the axes of the electrodes and which extends symmetrically through the space between tips of the electrodes when they are engaged with the workups. This assures that DIOVement of the electrodes will have their axes substantially perpendicular to the work-piece to be welded when engaged with the workups.
The compound electrode holder 24 includes a first element 68 and a second element on. The element 68 has two side plates 72 and 74, upper portions of which are connected by a tie bar or rod 76. The upper ends of the side plates 72 and 74 are connected by a pivot pin 78 to the frame legs 34 and 36 at a position above the pivot pins 60 and 62 and to the rear there-of, near the terminal block 20 of the transformer 12. Lower ends of the side plates 72 and 74 have flat stops 80 and 82 which engage raised stop surfaces 84 and 86 on the transverse web 38 when the element 68 is in its lowest pivotal position.
Lower ends of the first element 68 are pivotal connected by a pivot pin 88 to a lower enlarged end 90 of the second I holder element 70 with insulating bushings 91 there between.
The pivot pin 88 is positioned such that it is coaxial with the axes of the pins 6Q and 62 when the stops 80 and 82 engage the stop surfaces 84 and 86. Further pivotal movement of the second element on toward the first electrode holder 22 is then in an arcuate path having the same radius and center as the electrode holder 22. An outer, upper end 92 of the holder element 70 carries a long electrode 94. Like the axes of the pivot pins 60 and I the axis of the pivot pin 88 is on a line substantially perpendicular Jo the axes of the electrodes when engaged with the workups and the line also symmetrically extends through the space between tips of the electrodes.
An intermediate portion of the element 70 has outwardly extending ears 96 and 98 carrying insulating stops 100 and 102 which project reawardly from the ears. The stops engage pro-jetting tabs 104 and 106 on intermediate portions of the side plates 72 and 74 of the first element 68 when the second eye-mint 70 is raised, so that the first and second elements 68 and 70 then move as a unit. The electrode 94 then travels in an arcuate path Whitehall a radius having its center at the axis of the pivot pin 78.
Springs 108 and 110 are connected between the first and second elements 68 and 70 specifically between the projecting tabs 104 and 106 and intermediate portions of the element 70.
When the second element on is then moved toward the first elect trove holder 22, as from the position of jig. 2 toward the position of jig. 1, the two elements 68 and 70 move as a unit until the stops 80 and 82 engage the stop surfaces 84 and 86.
The element 68 then remains stationary while the element 70 moves further toward the electrode holder 22 as the electrode 94 nears and then engages the workups. At this time, the path of the electrode 94 is on a radius having its center a the axis of the pivot pin 88 which is also the axes of the pivot pins I and 62. This assures that the axes of the electrodes 30 and 94 are substantially perpendicular Jo the surfaces of the workups Jo be welded and move on a common arcuate path. The electrodes thereby engage the workups on a common axis and there is no tendency for the tips of the electrode Jo push or pull relative Jo the workups as can occur if the elect troves move about separate centers or a center which is other in than on a line perpendicular to the electrode axes and sum-metrical with respect to the space between the tips of the electrodes.
The second element 70 has a rearwardly-extending project-in block 112 to which power is supplied by a second laminated shunt 114. One end of the shunt 114 is electrically connected to the block 112 by machine screws (not shown) and the other end of the shunt is connected to the terminal block 20 by similar machine screws or the like. The shunt 114 is located near the pivot pin 78 so that minimal flexing movement of the shunt 114 occurs as the compound electrode holder 24 moves between its extreme positions of Pigs. 1 and 2. Like the shunt 28, the shunt 114 is short to minimize secondary electrical losses.
The compound electrode holder 24 can be moved by various means. However, a fluid-operated cylinder and specifically a pressure intensifier cylinder 116 is preferred. The pressure intensifier cylinder can be of the type shown in my U. S. Patent 4,135,076 issued January 16, 1979, and will not be discussed in detail The rod end of the cylinder is pivotal connected I to upper ends of the main frame lets 34 and 36 by pivot pins 118 and 120. A piston rod 122 has its outer end pivotal connect ted to ears 124 by a pivot pin 126, the ears being separated by a groove 128 in the second element 70.
'hen the compound electrode holder 24 is in its maximum raised pivotal position, there is ample room between the elect troves 30 and 94 for a workups to be placed in welding position.
This includes work pieces having deep Shaped cross-sectional shapes. when the piston rod 122 is extended and the compound electrode holder 24 moves toward the electrode holder 22, the n elements 68 and 70 move together with the electrode 94 pivoting in an arcuate path around the pivot pin 78 (see jig. 4). When the stops on and 82 engage the stop surfaces 84 and 86, further extension of the piston rod 122 then causes the electrode 94 to move in a shorter arcuate pettily with the center being at the axis of the pivot pin 88. Any movement of the electrode 30 likewise is in an arcuate path having a center at the axes of the pivot pins I and 62 which are coaxial with the axis of the pivot pin 88. Thus, as the electrodes 30 and 94 are near the workups and continue movement to engage the workups, the 2 n movement is on a common arcuate path with the center of the path being on a line substantially perpendicular to the axes of the electrodes and extending symmetrically through the space between the electrode tips so that the electrodes engage the workhouse with their axes substantially perpendicular thereof.
Thus 9 the high pressure of the electrodes on the workups is substantially perpendicular to the workups so that there is no pushing or pulling of the electrodes relative to the workups.
The large radius of the path or stroke of the electrode I throughout most of its length enables the electrode 94 to clear a workups which could not be achieved in many instances I
if the electrode I were moved solely through an arcuate path having its center at the axis of the pivot pin 88. Further, the arcuate path of the electrode holder 24 enables the overall height of the apparatus to be substantially less than with the C-type electrode holders heretofore used. The arcuate path also enables the shunts or cables to be shorter, reduce in the tendency to self-destruct due to inductive kick.
The shorter cables also produce shorter secondary loops no-suiting in less electrical losses. The smaller electrical losses enable smaller transformers or other power sources to be employed. lulled quality is also improved since the movement or bend of the shunt or cable is less and minimal variation in the losses in the secondary loop results. Since a smaller power source and less electrical energy are needed and lower secondary voltage can be used, expulsion is also reduced or eliminated. Expulsion occurs when some of the metal or mater-tat being wended or portions of the electrodes are blown away by excess voltage at the beginning of the resistance welding cycle.
Claims (20)
1. Apparatus for resistance welding comprising a trans-former having an output face, a first output terminal block at one portion of said face, a second output terminal block at another portion of said face, a pivotal supporting means ex-tending outwardly from said transformer, a first electrode holder, means electrically connecting said first electrode holder to said first output terminal block, a main frame con-nected to said first electrode holder and extending away there-from, means pivotally connecting said main frame to said pivotal supporting means, a compound electrode holder com-prising a first element and a second element, a first electrode having a first axis carried by said first electrode holder, a second electrode having a second axis carried by said second element, said first and second axes being substantially aligned when said electrodes are engaged with a workpiece, means pivot-ally connecting one portion of said first element with said main frame, means pivotally connecting another portion of said first element to said second element on a pivotal axis which is on a line perpendicular to the axes of said electrodes when engaging a workpiece, with the line passing symmetrically through the space between the electrode tips when engaged with the workpiece and said first element is in a predetermined pivotal position, means electrically connecting said second element to said second output terminal block, stop means be-tween said elements for causing the elements to move together when said second element is moved away from said first elec-trode holder, said first element having stop means for limiting the extent to which said first element can move toward said first electrode holder, resilient means connected between said first and second elements for enabling said second element to move further toward said first electrode holder when said first element is stopped, and means for moving said second element toward and away from said first electrode holder.
2. Welding apparatus according to claim 1 characterized by said moving means comprising a fluid-operated cylinder pivo-tally supported by said main frame and having a piston rod pivotally connected to said second element.
3. Welding apparatus according to claim 2 characterized by said fluid-operated cylinder being a pressure intensifier cylinder.
4. Welding apparatus according to claim 1 characterized by the predetermined pivotal position of said first element being the maximum pivotal position thereof toward said first electrode holder.
5. Apparatus according to claim 1 characterized by said means pivotally connecting said main frame to said pivotal supporting means has a pivotal axis which is aligned with the pivotal axis of said pivotal connecting means between said elements when said first element is in the predetermined pivo-tal position.
6. Welding apparatus according to claim 1 characterized by said pivotal connecting means connecting said first element with said main frame being farther away from said electrodes than said pivotal connecting means between said elements.
7. Welding apparatus according to claim 6 characterized by said pivotal connecting means connecting said first element with said main frame being farther away from said first electrode holder than said pivotal connecting means between said elements.
8. Welding apparatus according to claim 1 characterized by said means electrically connecting said second element to said second output terminal block being a laminated U-shaped shunt.
9. Welding apparatus according to claim 1 characterized by said means electrically connecting said first electrode holder to said first output terminal block being a laminated shaped shunt.
10. Apparatus for resistance welding comprising a power supply, a first electrode holder, means electrically connect-ing said first electrode holder with said power supply, a first electrode having a first axis carried by said first electrode holder, a compound electrode holder comprising a first element and a second element, a second electrode having a second axis carried by said second element, said first and second electrode axes being substantially aligned when said electrodes are en-gaged with a workpiece, means pivotally supporting one portion of said first element, means pivotally connection another por-tion of said first element to said second element, stop means for limiting the extent to which said first element can pivo-tally move toward said first electrode holder, said pivotal connecting means between said elements having a pivotal axis which, when said first element is in its maximum pivotal posi-tion toward said first electrode holder, is on a line substan-tially perpendicular to the axes of said electrodes when en-gaged with the workpiece, with the line passing symmetrically through the space between the electrodes when engaged with the workpiece, stop means between said elements for causing said elements to move together when said second element is moved away from said first electrode holder, resilient means connected between said first and second elements for enabling said second element to move further toward said first electrode holder when said first element is stopped, and means for moving said second element toward and away from said first electrode holder.
11. Welding apparatus according to claim 10 characterized by said moving means comprising a fluid-operated cylinder having a piston rod pivotally connected to said second element.
12. Welding apparatus according to claim 10 characterized by means pivotally supporting said first electrode holder on an axis which is aligned with the pivotal axis of said pivotal connecting means between said elements when said first element is in its maximum pivotal position toward said first electrode holder.
13. Welding apparatus according to claim 10 characterized by said means pivotally supporting said first element having a pivotal axis which is farther from said electrodes than said pivotal connecting means between said elements.
14. Welding apparatus according to claim 13 characterized by said axis of said pivotal supporting means for said first element being farther from said first electrode holder than said pivotal connecting means between said elements.
15. Welding apparatus according to claim 10 characterized by said means pivotally supporting said first element having a pivotal axis which is farther from said first electrode holder than said pivotal connecting means between said elements.
16. Apparatus for resistance welding comprising a power supply, a first electrode holder, means electrically connecting said first electrode holder with said power supply, a first electrode having a first axis carried by said first electrode holder, a compound electrode holder comprising a first element and a second element, means electrically connecting said compound electrode holder with the power supply, a second electrode having a second axis carried by said second element, said first and second electrode axes being substantially aligned when said elec-trodes are in a position to engage a workpiece, means pivo-tally supporting one portion of said first element, means pivotally connecting another portion of said first element to a portion of said second element spaced from said second elec-trode, stop means for limiting the extent to which first element can pivotally move toward said first electrode holder, said pivotal connecting means between said elements having a pivo-tal axis which, when said first element is in its maximum pivo-tal position toward said first electrode holder, is on a line substantially perpendicular to the axes of said electrodes when in a position to engage the workpiece, with the line passing symmetrically between tips of the electrodes when in the posi-tion to engage the workpiece, means for causing said elements to move together when said second element is moved away from the first electrode holder, means connected between said first and second elements for enabling said second element to move further toward said first electrode holder when said first element is in its maximum pivotal position toward said first electrode holder, and means for moving said second element toward and away from said first electrode holder.
17. Welding apparatus according to claim 16 characterized by means pivotally supporting said first electrode holder on an axis which is aligned with the pivotal axis of said pivotal connecting means between said elements when said first element is in its maximum pivotal position toward said first electrode holder.
18. Welding apparatus according to claim 17 characterized by said means electrically connecting said first electrode holder with said power supply comprising a laminated, U-shaped shunt.
19. Welding apparatus according to claim 18 characterized by said means electrically connecting said compound electrode holder with the power supply comprising a laminated, U-shaped shunt connected to said second element and located near said means pivotally supporting the one portion of said first ele-ment.
20. Welding apparatus according to claim 16 characterized by said means pivotally supporting said first element having a pivotal axis which is farther from said electrodes than said pivotal connecting means between said elements and which is farther from said first electrode holder than said pivotal connecting means between said elements.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/558,804 US4504725A (en) | 1983-10-26 | 1983-12-07 | Resistance welding apparatus with compound electrode holder |
| US558,804 | 1983-12-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1214523A true CA1214523A (en) | 1986-11-25 |
Family
ID=24231053
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000468228A Expired CA1214523A (en) | 1983-12-07 | 1984-11-20 | Resistance welding electrode holders |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1214523A (en) |
-
1984
- 1984-11-20 CA CA000468228A patent/CA1214523A/en not_active Expired
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| MKEX | Expiry |