CA1091773A

CA1091773A - Welding machine

Info

Publication number: CA1091773A
Application number: CA295,027A
Authority: CA
Inventors: Edward G. Spisak
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-02-14
Filing date: 1978-01-16
Publication date: 1980-12-16
Also published as: DE2806185A1; JPS53127342A; FR2380102A2; GB1568934A

Abstract

ABSTRACT
A welding machine for automatically welding abutting workpiece portions in which the workpiece portions are aligned by a gauge and after being clamped in such a position, the gauge is automatically removed and the clamped ends are moved into abutting relationship to each other to be welded together. After the weld is completed the gauge is moved automatically to engage and eject the welded part and at the same time position the gauge and place the machine in condition to receive the next part to be welded.

Description

A-341 S ~ S PRODUCTS
This application relates to improvements of my Canadian application i~ ~L~3,fS//
.; Serial Number ~6~ , filed 22 October, 1976.
N This invention relates to welding machines and partic- -ularly welding machines for automatically and accurately posi-tioning and welding parts to each other and ejecting the welded parts from the machine.
In the repeated welding of like parts in manufacturing processes it is necessary that the parts to be welded be accu-- rately positioned relative to each other and to a welding head during the welding process and that the parts be removed rapidly in readiness for the next parts to be welded.
It is particularly difficult to accurately align adja-cent edges of workpiece portions so that they can be welded by plasma type welders. With such welding apparatus it is neces-sary that the edges to be welded be brought together very ac-curately and once the weld begins the workpiece portions remain stationary relative to each other as opposed to some forms of butt welding in which the edges actually are forced against each ~ other to displace some of the metal which is melted during the :` 20 welding process.
It is an object of the invention to provide an auto-matic welding machine by which adjoining edges of parts are accu-rately positioned relative to each other and to a welding head.
It is another object of the invention to provide a welding machine including a gauge for accurately positioning the parts relative to each other and in which the gauge is employed ~ to eject the parts from the machine.
- Still another object of the invention is to provide a machine in which parts are accurately positioned relative to each other and to the path of a welding head and are welded -1- ~k - . . . .

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together and are ejected from the machine all at a high rate of speed.
The invention provides a welding machine for adjoining workpiece portions together having a gauge means movable between a first and second position, a pair of clamp means to clamp each of the workpiece portions disposed at opposite sides of the gauge means and being operable to grip opposite surfaces of said por-tions and holds said portions in engagement with said gauge means and in alignment in the same plane when the gauge means is in the first position, the pair of clamp means each including a support ....
~. member and a clamp element movable relative to the support mem-10 ber, the workpiece portions each being initially positioned in ,. .
.~ engagement and at an angle to the gauge means such that movement .?
. of the clamp elements into engagement with the workpiece por-:
. tions exerts a force having a component towards the gauge bar :.~
pressing the ends of the workpiece portions into firm engagement ~- 15 with the gauge means, said gauge means having a predetermined width, means to move the clamp means towards each other when the gauge means is in the second position to move the workpiece por-tions towards each other, the clamp means being movable a dis-tance greater than the thickness of the gauge means to bring the 20 workpiece portions into tight abutting relationship with each other, a welding head supported for movement in close proximity ~: to the abutting workpiece portions, and means to move the weld-ing head for welding of the workpiece portions to each other to form a finished workpiece.
Figure 1 is a side elevation of the welding machine embodying the invention with portions of the machine shown sche-matically;
Figure 2 is a front elevation of the welding machine seen in Figure l;

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-. Figure 3 is a view of a portion of the welding machine , taken generally on line 3-3 in Figure~l, , . .
igure 4 is a view of a portion of the welding machine .` seen in Figure 2 but at an enlarged scale and showing a different condition of operation;
Figure 5 is a schematic view showing the electrical control circuit and the various associated components of the welding machine;
Figure 6 is a view of a portion of the welding machine , . .
seen in Figure 2 but at an enlarged scale and illustrating the - initial positioning of the workpiece portions;

, Figure 7 is a view similar to Figure 6 showing a subse-. quent condition of operation in which the workpiece portions are . clamped; ' -Figure 8 is a view similar to Figure 7 showing another condition of operation, and ~; :

~:......... Figure 9 is a view similar to Figure 8 showing the ~ . .
workpiece portions in position for welding.
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r~'' Referring to the drawings a welding machine embodying ., I ..
~: 20 the invention is designated at 10 and includes a welding head ,~, .
12, a clamp assembly 14, and a gauge member 16, all of which are supported on a frame structure 18. The welding machine 10 is ,~.` particularly adapted for welding together the abutted ends 20 of a strip of metal which has been preformed into a general cir-. 25 cular hoop 22.
. As best seen in Figure 2, the clamp assembly 14 in-cludes a left clamp assembly 24 and a right clamp assembly 26 ;. which are used to hold the respective ends 20 of the hoop 22 during the welding operation. The left clamp assembly 24 in- ::
~, 30 cludes a stationary work support 28 mounted in the stationary :~,........ .
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position relative to the frame 18 and a vertically movable clamp member 30 which can be moved vertically relative to the work sup-port 28 by means of a hydraulic cylinder 32.
The right clamp subassembly 26 includes a work support 34 which is supported relative to the frame 18 for horizontal :.: movement relative to the work support 28. The work support 34 has a bracket member 36 extending upwardly to support a hydrau-~' lic cylinder 38, the rod end of which is provided with a clamp member 40. The cylinders 32 and 38 are operated simultaneously from a common hydraulic source, not shown, and are disposed at ;; a slight angle to the vertical so that the clamp members 30 and ~,;
40 are moved generally radially of the hoop 22 relative to the . ends 20 during clamping and unclamping of the hoop 22 in a work-; ing position. The clamp member 40 together with the cylinder ~ 15 38 and the bracket 36-all slide horizontally as a unit with the - work support 34. Such movement is accomplished by a hydraulic . . ~ .
actuator 41 which retracts to move the assembly to the left in Figure 2 and which extends to move the slide assembly to the : right.
The gauge member 16 is supported on the frame 18 for movement generally horizontally between retracted and extended , position shown in full line and broken line positions, respect- ;
ively in Figure 1. In the extended position the gauge member ~; 16 is disposed between the right and left clamp subassembly 24 . 25 and 26 when the latter are in spaced apart relationship as seen in Figure 4. Movement of the gauge bar 16 is accomplished by the hydraulic cylinder 46 supported in a generally ho~izontal :;
position on the frame 18 at the rear of the machine 10. ~:
The hoop 22 is placed in position in the welding ma- :~
chine 10 when the clamp assembly 24 and 26 are in spaced apart . : :, : : . . ; .

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relationship as seen in Figure 4. This is accomplished by plac-ing the ends 20 on the left work support 28 and the right work support 34 with the ends 20 in abutting relationship with the gauge member 16. Thereafter the clamps 30 and 40 are moved down-wardly by the hydraulic cylinders 32 and 38 into engagement with the ends 20 to clamp them against the respective supports 28 and 34.

, The welding head 12 is supported relative to an over-'~ head track structure 48 forming part of the frame 18 for move-~, ment longitudinally of the track structure. The welding head ` assembly 12 includes a welding nozzle 52 which in the preferred embodiment of the invention is a nozzle of the plasma type welder more fully disclosed in United States patent 2,806,124 to R. M.
- Gage granted 9/10/57. The welding nozzle 52 includes a generally vertically extending tubular portion 53 through which the arc and arc gases pass. The nozzle 52 is mounted on a guide bracket 54 ; for movement therewith. The guide bracket 54 is pivotally mounted .
`' for swinging movement about an axis indicated at 56 relative to a movable mounting structure or trolley 58. As seen in Figure 2, - 20 the trolley 58 is connected to its upper end to grooved member 60 ~i which slidably receives a tongue member 62. The tongue member 62 is mounted rigidly on the track structure 48 of the frame 18 and has a generally V-shaped configuration which receives a lon-gitudinally extending screw 66. As seen in Figure 1 the screw 66 is connected by means of a coupler 68 to direct current motor 70 which is reversible and of variable speed. Rotational move- -ment of the reversible motor 70 is transmitted by way of the coupler 68 to the screw 66 which is threadedly engaged with a drive portion 72 (Figure 2) forming part of the grooved member 60. Consequently, rotational movement of the motor 70 causes , . ~' . :
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sliding movement of the grooved member on the tongue member 62 and movement of the welding nozzle 52. Movement of the welding nozzle 52 is used to actuate electrical switches in a control circuit to be discussed later.
In addition to movement longitudinally of the track structure 48, the nozzle 52 may be pivoted about the axis indi-cated at 56 between the full line and the broken line positions - shown in Figure 1. A tension spring 74 is interposed between the guide bracket 54 and the trolley assembly 58 so that the welding nozzle 52 is continuously urged towards its vertical position seen in Figure 1.
A limit stop 78 is mounted in the path of movement of :, the welding nozzle 52 so that as the welding head 52 moves from left to right as viewed in Figure 1, the guide bracket 54 engages ~; 15 stop 78 and causes the welding nozzle 52 and the support bracket 54 to pivot to the full line position.
, At a forward position of frame 18, welding machine 10 is provided with a gate 80 which is mounted to slide vertically between open and closed positions. The gate 80 is balanced by a counterweight 81 so that manual movement is required by the :.
~ operator to move the gate to its closed position. Closing the :
gate serves to bring it into engagement with a latch mechanism 82 to maintain it in its closed position and opening of the gate is achieved electrically by actuation of a solenoid forming part of the latch 82. The purpose of the gate 80 is to shield an operatcr of the machine from the operation of the welding nozzle 52.

Also located at a forward part of the machine 10 is a ; guide block 84 which as seen in Figure 3 has a V-notch 85 to ~;~ 30 receive the forward tapered end 86 of the gauge 16 to insure '~ -6-..

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that the gauge is accurately aligned in parallel relationship to .:
- the track structure 48 and therefore to the path of the welding -~ head. When the tapered end 86 is disposed in the V-notch 85, ; the gauge 16 is accurately aligned and it is at this time that the ends 20 of the workpiece are placed into abutting relation-ship to accurately gauge the ends 20 of the workpiece 22.
- In the unloaded initial condition of the welding ma-- chine 10, the left and right clamp subassemblies 24 and 26 will ,,, :
, be spaced apart horizontally with the gauge member 16 disposed ~
., ~ 10 therebetween as best seen in Figure 4. The left and right clamps -~
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30 and 40 will be in their open position with the hydraulic cyl~
; inders 32 and 38 retracted. At the same time the welding nozzle 52 will be in its fully tilted position with the guide bracket 54 in engagement with the stop member 78 so that the welding head 52 is disposed at an angle to the vertical with the end of -the nozzle 52 above the path of movement of the gauge member 16.
Under the above conditions, an operator utilizing the - machine places an elongated strip of material which has been pre~
formed into a generally circular hoop 22 with the ends 20 on the work supports 28 and 34 so that the ends 20 abut the gauge member 16 at its opposite sides. When the strip of material to be welded is relatively thin and flexible it is unnecessary to pre-form the material into a generally circular hoop 22 since the material can be easily flexed by the operator to place the oppo-site end edges 20 in abutment with the gauge member 16. The opposed surfaces 75 of the gauge bar 16 are accurately formed to ; be parallel to each other so that as seen in Figure 6 when the ends 20 of the workpiece portions are placed in engagement with the surfaces 75, they also are parallel. Moreover, when the part is not preformed or the end portions are allowed to remain . .

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flat, the workpiece portions extend at an acute angle to the gauge member 16 as seen in Figure 6. Upon acutation of a manual ~- control such as a foot switch 90, seen in Figure 5, the hydrau-lic actuators 32 and 38 are extended so that the clamp members .. .
30 and 40 move toward the work supports 28 and 34. Initially the outboard edges 76 of the clamps 30 and 40 contact the work-piece portions and grip them to ho]d the workpiece portions at an angle to the gauge bar 16 as seen in Figure 6. Subsequent extension or the cylinder 32 and 38 causes additional movement of the clamp members 30 and 40 to bring the replaceable clamp elements 77 into engagement with the top surface of the workpiece , 22. Additional increments of movement of the hydraulic cylinders .'.................................................................... .
causes the clamps 30 and 40 to rock or pivot about the heel 76 and bend the workpiece portions to force the end edges 20 of the ` 15 workpiece portions downwardly as they remain in tight engagement with the opposite surfaces 75 of the gauge member 16 until the workpiece and gauge member assume the relative position illu-~` strated in Figure 7. In this condition the edges 20 of the work-piece portions are in tight abutting relationship to the surfaces 75 and the workpiece portions are disposed in a common plane as -; well as at right angles to the surfaces 75. As a result, the -~ ends 20 are very accurately aligned and ln tight, parallel rela-tionship to each other. Only a limited amount of rocking of the clamp members 30 and 40 is required and in the disclosed embodi-ment such mQvement is accomplished by affording a relatively loose fit in the pin and toggle arrangement connecting the cy-linders 32 and 38 to the clamps 30 and 40, respectively.
With the workpiece or hoop 22 firmly gripped by the '' "

~917q3 A-341 S & S PRODUCTS
clamp subassemblies 24 and 26 the operator pulls down the gate 80 from its elevated position. As the gate 80 reaches its lower position it is automatically latched in a closed position by the latch 82 and actuates a switch 92 controlling the hydraulic actu-ator 46 so that the latter is retracted and causes the gauge mem-ber 16 to move toward the right as viewed in Figure 1. As the gauge 16 approaches its extreme right position, a switch 94 (seen in Figure 5) is energized causing the motor 70 to begin rotation so that the welding head 12 with the nozzle 52 is advanced to-:;
ward the left in Figure 1. Initial leftward movement brings the guide bracket 54 out of engagement with the stop 78 so that the ;. ,:
spring 74 is effective to swing the welding head together with ` the nozzle 52 to a generally vertical position.
` As the welding head is moving to its vertical position the guide-bracket 54 disengages from switch 96 causing hydraulic - -actuator 41 to move the right clamp subassembly 26 toward the left as viewed in Figure 2 to occupy the gap once occupied by the gauge member 16. Such horizontal movement of the right clamp subassembly 26 is for a greater distance than the thick-ness of the gauge bar 16, that is, greater than the originalspacing of the ends 20 of the workpiece portions. Since the workpiece portions were originally aligned in the same plane and at opposite sides of the gauge bar 16 movement of the clamp subassembly 26 initially brings the ends 20 of the hoop 22 into abutting engagemen~ with each other. After the parts are in abutting engagement the clamp assembly 26 is moved an additional amount d~lring which time the associated workpiece portion slips between the clamp member 40 and support member 34. This forces the ends 20 tightly against each other to the abutting relation-.. . .
ship in which they are held during the welding operation. To ....
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" 1~9173 ; A-341 S & S PRODUCTS
facilitate this tight abutting relationship of the ends 20, the ~; hydraulic actuator 38 applies a lesser degree of pressure to the right clamp member 40 than is applied by the hydraulic actuator 32 to the left clamp member 30. This may be accomplished by in-` 5 suring that cylinder 38 has a smaller internal diameter than ' cylinder 32 or by limiting the hydraulic pressure delivered to cylinder 38. In an actual embodiment of the invention the gauge bar has a thickness of approximately five-eights of an inch so that after removal of the gauge bar and movement of the clamp subassembly 26 the latter moves a distance of five-eights of an inch to a~sorb the space once occupied by the gauge bar as seen in Figure 8. The subassembly 26 continues to move an additional amount of approximately one quarter of an inch which requires the workpiece portion held by the subassembly 26 to s~ip that , 15 amount before the clamp subassembly comes to a stop as determined hy the full stroke of cylinder 41 or a stop 79 as seen in Figure 9. Once the workpiece portions reach this position they are .
held in tight engagement with each other but no additional force is applied to press the ends 20 against each other.
When the clamp subassembly 26 reaches a final position as seen in Figure 9, the portions are spaced apart only suffi-ciently to allow the welding nozzle to have access to the abut-ting edges 20 for conducting the welding process. In this posi-tion the expendable eage portions 77 support the workpiece por-tions and also tend to absorb heat generated by the weld and dissipate it to the clamp members 30 and 40 to prevent distor-tion of the edge portions to insure a uniform, smooth weld.
During the time that the left clamp assembly moves to a closed position, leftward movement of the weldlng head 12 con-tinues until the nozzle 52 reaches the beginning of the area to :"

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: be welded at which time a limit switch 98 as seen in Figure 5 is `~ engaged by the moving trolley 58 to initiate the welding process.

The welding head 52 travels the length of the seam formed by the . . .
abutting ends 20 and is in alignment with the original location of the left surface 75 of the gauge bar 16. At the end of the weld, another switch 100 is engaged by the trolley 58 to dis-continue the welding operation~ Simultaneously with the actua-::`........ tion of the switch to discontinue the welding operation, the ~'- hydraulic actuators 32 and 38 are retracted to release the clamp .. . .
. 10 subassemblies 24 and 26 and the right clamp subassembly 26 moves '~ horizontally to the right as viewed in Figure 2, During this ~- latter movement the counterweighted door 80 is unlatched so that . it is permitted to move upward to an open position~
: After discontinuation of the weld and welding nozzle .
52 travels an additional amount so that the trolley 58 engages another limit switch 102 which reverses the rotation of the motor 70 and returns the welding head assembly 12 to the right in Fig-:~ ure 1. Reversal of direction of welding head serves to actuate . the hydraulic cylinder 46 so that it is extended causing the gauge member 16 to move to the left as viewed in Figure 1. The : left end of the gauge member will enter the gap between the . right and left clamp subassemblies 24 and 26 and engage the weld-- ed hoop 22 and eject it from the work supports 28 and 34. At :

the same time the left end of the gauge member 16, which is form-. 25 ed with the cam surfaces at 85, engages the lower end of the guide :; bracket 54 to tilt the welding head 52 about the pivot 56. There-after the welding nozzle 52 is moved to the right at an angle in elevated relation to its welding path with the guide bracket 54 in engagement with the top of gauge member 16. As the guide bracket 54 engages the stop member 78, the welding head and . .

, :~ ` 109i~73 A-341 S ~ S PRODUCTS
bracket 54 is tilted an additional amount to engage switch 96 and the motor 70 is deenergized to terminate further rightward : movement of the welding head 12. At this point in the operation, ~: the welded hoop 22 has been ejected from the machine and partsare in condition to receive the next workpiece to be welded.
.~ In the interest of clarity the electircal circuit by .; which switches 90 through 102 are actuated is shown in Figure 5 .-.
in association with schematically represented components of the ~.
i .~
welding machine 10.
~ 10 Switch 90 is connected to a source of power 104 and is ,, operated by the foot of the operator to close a circuit to a control 91 which simultaneously actuates solenoid valves extend- ~ .
ing the clamp cylinders 32 and 38. Switch 92 which also is con- ~ -nected to the source of power 104 is closed in response to clos- -ing of the gate 80 to actuate a solenoid valve associated with . cylinder 46 to retract gauge 16. Retraction of the gauge cylin-,~.
. der 46 actuates a switch 94 closing the circuit between the source of power 104 and a reversible control on the motor 70 to move the welding head 12. Switch 96 is normally held in an open position by the tilted welding nozzle 52. Movement of the weld-. ing head 12 permits the nozzle 52 to move to a vertical position ' so that switch 96 closes the circuit between the power source ~: :
; 104 and a solenoid controlled valve associated with cylinder 41 ,;
~: to retract the latter and close the right clamp assembly 26 re-lative to the left clamp assembly 24. Continued forward move-ment of welding head 12 actuates switches 98, 100 and 102 in 6 succession. Switch 98 is normally open and switch 100, which is connected to the source of power 104 is normally closed and as ~. the welding head 12 engages switch 98 the latter is closed to ;, 30 complete the circuit through the switch 100 and from the power . ' .
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1'773 A-341 S ~ S PRODUCTS
source 104 to initiate the welding process. When the welding head 12 engages the switch 100 it opens it to discontinue the welding step and simultaneously releases a solenoid associated with latch 82 to permit the gate 80 to move upwardly to an open position. At the same time switch 100, which also is connected to the control 91 and to the cylinder 41, causes cylinders 32 and 38 to simultaneously retract to open the clamp assembly 24 ; and 26 and causes cylinder 41 to extend to move the clamp 26 horizontally to an open position. Continued movement of the welding head 12 actuates the switch 102 which is connected to the control on the motor and serves to reverse the direction of `-~ rotation and at the same time is connected to actuate the sole-noid controlled valve on the cylinder 46 to extend the gauge 16.
When the welding head moves rearwardly it reengages the switch 96 to close the circuit between the power source 104 and the motor 70 so that the latter stops its rotation.
The circuit is such that with the clamp assemblies 24 and 26 in closed position in response to actuation of the valve 90, subsequent closing of the gate 80 and switch 92 serves to automatically actuate each of the remaining control switches 94 -through 102 in sequence to bring about automatic control of the various devices.
Although the preferred embodiment of the invention utilizes hydraulic cylinders 32, 38, 41 and 46 it will be under-stood that various forms of linear actualors and fluid motors ... . .
-~ may be used.
A welding machine has been provided for automatically welding abutting ends of a workpiece such as ln a ring formed of a strip of material in which the ends are accurately aligned by ~;; 30 a gauge which moves out of position to permit the ends to be "

lQ9~73 A-341 S & S PRODUCTS
moved into accurate position relative to each other and in tight . engagement for welding. After welding the welded workpiece are .. .
. ejected from the machine and the machine is placed ln condition for receiving the next workpiece and the movements of holding . 5 gauging, welding and ejecting the wo~kpiece occur in timed se-quence.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A machine for welding adjoining workpiece portions together comprising; gauge means movable between a first and second position, a pair of clamp means to clamp each of said workpiece portions disposed at opposite sides of said gauge means and being operable to grip opposite surfaces of said por-tions and hold said portions in engagement with said gauge means and in alignment in the same plane when the gauge means is in said first position, said pair of clamp means each including a support member and a clamp element movable relative to said support member, said workpiece portion being initially positioned in engagement and at an angle to said gauge means such that move-ment of said clamp elements into engagement with said workpiece portions exerts a force having a component towards said gauge bar pressing said end portions into firm engagement with said gauge bar, said gauge means having a predetermined width, means to move said clamp means towards each other when said gauge means is in said second position to move said workpiece portions towards each other, said clamp means being movable a distance greater than the thickness of said gauge means to bring said workpiece portions into tight abutting relationship with each other, a welding head movable supported for movement in close proximity to the abutting workpiece portions, and means to move said welding head for welding said workpiece portions to each other to form a finished workpiece.

2. The combination of Claim 1 wherein said clamp means are operative to initially engage and clamp said workpiece por-tions at a location spaced from the ends of said workpiece por-tions when the ends are in engagement with said gauge means and with said workpiece portions diverging away from opposite sides thereof at an angle, said clamp means being operative to sub-sequently engage said workpiece portions at a second location closely adjacent said ends of said workpiece portions to move said workpiece portions from an angle relative to the surfaces of said gauge means to a position in which said portions are disposed in said plane.

3. The combination of Claim 1 wherein one workpiece portion slips relative to its associated clamp means upon re-lative movement of said clamp means towards each other.

4. The combination of Claim 1 and further comprising a pair of fluid operated cylinders associated with each of said clamp elements, respectively, one of said cylinders applying a smaller force to one of said clamp elements than the other of said clamp elements to permit sliding movement of one workpiece portion between a clamp element and support member upon movement of said clamp means toward each other.

5. The combination of Claim 1 wherein said clamp means at one side of said gauge means remains stationary during move-ment of the other of said clamp means toward said one clamp means.

6. The combination of Claim 2 wherein said clamp elements include replaceable edge portions engageable with said workpiece portions at said second location to absorb heat generated during welding.

7. The combination of Claim 4 wherein said clamp elements are connected to said fluid operated cylinders for rocking movement relative thereto.