US3552629A

US3552629A - Method and machine for forming lap welded aluminum can bodies

Info

Publication number: US3552629A
Application number: US845633A
Authority: US
Inventors: Ronald H D Armbruster; Roger J Nelsen
Original assignee: EW Bliss Co Inc
Current assignee: EW Bliss Co Inc
Priority date: 1969-07-07
Filing date: 1969-07-07
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05

Abstract

Method and apparatus for forming lap welded can bodies by wrapping rectangular metal blanks about a cylindrical forming horn and welding the overlapped joint portions ultrasonically while the blank is clamped to the horn.

Description

United States Patent Ronald H. D. Armbruster Battle Creek;

Roger J. Nelsen, Hastings, Mich. [2|] Appl. No. 845,633

[22] Filed July 7,1969

[45] Patented Jan. 5,197!

[73] Assignee E. W. Bliss Company Canton, Ohio a corporation of Delaware Continuation of application Ser. No. 573,971, Aug. 22, 1966, now abandoned.

[72] Inventors [54] METHOD AND MACHINE FOR FORMING LAP WELDED ALUMINUM CAN BODIES 15 Claims, 21 Drawing Figs.

52 11.5. C1 228/1, 29/4701; 1 13/7. 113/8. 1 13/120; 22s/1s.228/17 Primary Examiner.lohn F. Campbell Assistant Examiner-Robert J. Craig AtrorneyMeyer, Tilberry and Body ABSTRACT: Method and apparatus for forming lap welded can bodies by wrapping rectangular metal blanks about a cylindrical forming horn and welding the overlapped joint portions ultrasonically while the blank is clamped to the horn.

FORMING STATION 101.512 STATION /w1-:1 o1-c STATION 285 215 290 281 15 17 1e 1 3 1 fl 1/ 2 1. e96 295 29s A 1\\/i\ \\\\\\\1 ,1 j\\ \Y/ X ,17 295 286 292 293 I? X 295 293 2 e9 PATENTEU JAN 5197! SHEET 01 HF PATENTEUJAH 519?! SHEET c2 [1F INVENTORS. D, ARMBRUSTER &

RONALD H. ROS ER J. NELSEN May/1,, 7M 8 Badly ATTORNEYS PATENTEU JAN 5 I97! 'SHEET 03 [1F O INVENTORS. RONALD H. D. ARMBRUSTER 8 RCffiER J. NELSEN Me 746m; 6: 8w,

ATTORNEYS PATENTEUJAN 512m SHEET 0U 0F INVENTORS. H. D. ARMBRUSTER 84 ROGER J. NELSEN RON ATTO R N EYS PATENTEDJAN 519?! I 3,552,629

sum new 12 INVENTORS. RONALD H. D. ARMBRUSTER 8a ROgER J. NELSEN Mega, 7% g 80% ATTORNEYS PATENTEU JAN 51911 SHEET 09 0F I NVENTORS RONALD H. D. ARMBRUSTER 8x H6. 50 NELSEN Megmfidmq 8 80d? ROGER J. BY

ATTORNEYS Pmmmm slam 3552.629

SHEET 10 0F 12 RONALD H. D. AERMBRUSTER &

ROGER J. NELS N ATTORNEYS METHOD AND MACHINE FOR FORMING LAP WELDED ALUMINUM CAN BODIES This application is a continuation of Ser. No. 573,971, filed Aug. 22, 1966, and now abandoned. The present invention is directed to the can making art and more particularly to an improved machine for making can bodies.

The invention is particularly applicable for making can bodies from aluminum sheets and will be described with particular reference thereto; however, it is appreciated that the invention is capable of broader application and could be used to produce a variety of relatively thin-walled tubular members from many materials.

As used in this application, tubular member refers to any hollow, relatively thin-walled body having a substantially constant cross section of generally circular configuration.

In the can making art it has become desirable to form can bodies from aluminum. The use of aluminum for cans is advantageous because of its light weight and inherent corrosion resistance. However, because of difficulties experienced in soldering and welding aluminum, the methods used to produce the standard plated steel can cannot readily be adapted to the production of aluminum cans. Consequently, the use of aluminum as a can body material has necessitated different production methods.

In general, these production methods have been directed to various impact extrusion, deep drawing, and ironing processes; with some use of heat welding processes. Because of inherent inherent problems with these processes, the can bodies produced have not been entirely satisfactory.

For example, in making aluminum cans by impact extrusion and deep drawing processes, it is very difficult to hold the desired tolerances and maintain the wall thickness of the can body uniform. In order to overcome this problem it is necessary to produce cans which have a wall thickness generally greater than ideally necessary, to assure that the variations in wall thickness will not result in some portion of the wall being too thin. As a consequence, more material than desirable is used to produce cans by this process.

The use of heat welding processes is likewise unsatisfactory. In order to weld aluminum by most current heat welding processes, the welding must be carried out in an inert atmosphere. This necessitates special equipment which does not lend itself to high-speed production methods. Further, the can body resulting from a heat welding process is discolored along the weld seam, thus producing acan having an undesirable final appearance. Additionally, the metallurgical properties of the aluminum are often adversely affected. It is also known that aluminum is a good heat conductor; therefore, normal heat welding processes are inappropriate because the heat energy is dissipated from the welding area too rapidly to produce a sound weld. For these reasons, the extrusion process mentioned above has generally been used to produce thin walled aluminum cans with the resulting disadvantages.

The present invention overcomes the above problems and provides an apparatus adapted to produce can bodies from aluminum sheets in a manner that provides a can body having a uniform wall thickness and a side seam with none of the above-mentioned undesirable characteristics.

In accordance with the present invention an apparatus is provided for forming a generally cylindrical can body from a metal blank which has opposed edges and an intermediate portion between the edges which terminates in the edges. The apparatus comprises a forming member having an outer generally cylindrical surface and a longitudinal axis. Means are provided to clamp the intermediate portion of the blank against the surface along a contact band generally axial of the surface. A first movable member is provided for wrapping the first of the blank portions around the surface of the forming member in a first circumferential direction, and a second movable member is provided for wrapping the other blank portion around the surface in a second circumferential direction opposite the first. The edges of the blank are spaced sufficiently to form an overlapped joint when the blank portions are wrapped about the forming member. An ultrasonic welding means is provided which is movable against the overlapped joint for welding at least portions of the joint.

In accordance with another aspect of the present invention, a method is provided for forming a can body from a sheet aluminum blank having opposed edges and an intermediate portion which has two oppositely extending blank portions which terminate in the edges. The method comprises wrapping the blank into a tubular element with the edges forming a longitudinally extending seam having contacting interface surfaces. A relatively rigid member is positioned against the seam and substantial clamping pressure applied tov clamp the seam and the rigid member together. The member is then vibrated at a frequency sufficient to produce dynamic shearing stresses and plastic deformation at the interface surfaces of the seam to cause at least portions of the interface surfaces to be welded together.

By use of the above apparatus and method, aluminum can bodies can be produced at a very high rate. Further, the wall thickness of the can is dependent only on the thickness of the blank used and not on the hard-to-control accuracy of extrusion, drawing or ironing apparatus. A

An object of the present invention is the provision of a machine for forming can bodies having a desirable final appearance.

Another object of the present invention is the provision of a method for forming can bodies from aluminum sheet material.

An additional object of the present invention is the provision ofa machine for making can bodies at a high rate.

A further object of the present invention is the provision of a machine for making lap welded aluminum can bodies.

A still further object of the present invention is the provision of a machine capable of producing aluminum can bodies having a uniform wall thickness. '1

These and other objects and advantages will become apparent from the following description used to illustrate the preferred embodiment of the invention as read in connection with the accompanying drawings in which:

FIG. 1 is an elevational view of the body making machine of the present invention;

FIG. 2 is a plan view of the machine shown in FIG. 1;

FIG. 3 is a sectional view taken on line 3-3 of FIG. 1 and showing the arrangement of the main drive shafts of the machine;

FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 2 and showing the driving arrangement for the sheet feeding mechanism and the mandrel expander pin arrangement;

FIG. 5 is a cross-sectional view taken on line 5-5 of FIG. 1 and showing the arrangement of the welding apparatus used in the present invention;

FIG. 6 is a cross-sectional view taken on line 6-6 of FIG. 2 and showing the clamp arrangements used at the forming and welding sections of the machine;

FIG. 7 is a cross-sectional view taken on line 7-7 of FIG. 6 and shows in detail the mechanism used to actuate the blank clamp carried in the forming arch;

FIG. 8 is a cross-sectional elevation taken on line 8-8 of FIG. 1;

FIG. 9 is an enlarged detail showing of the forming wing as sembly shown in FIG. 8',

FIG. 10 is a cross-sectional elevation taken on line l0-l0 of FIG. 1 and showing the arrangement of the welding arch assembly;

FIG. 11 is an enlarged view of the mass blocks as shown in FIG. 10;

FIG. 12 is a sectional view taken on line 12-12 of FIG. 10 and showing the drive arrangement used to move the mass blocks;

FIG. 13 is an enlarged view of the forming horn as viewed in FIG. 5;

FIG. 14 is a cross-sectional viewtaken on line 14-14 ofFIG.

FIG. 15 is a cross-sectional view of the forming horn taken on line 15-15 of FIG. 14 showing the horn expanded;

FIG. 16 is a cross-sectional view taken on line 16-16 of FIG. 14 showing the horn collapsed;

FIG. 17 is a cross-sectional view taken on line 17-17 of FIG.

FIG. 18 is a cross-sectional view taken on line 18-18 of FIG.

FIG. 19 is an end view of the forming horn shown in FIG. 13;

FIG. 20 is a cross-sectional view taken on line 20-20 of FIG. 14 and showing the welding tip in contact with the seam of a can formed on the forming horn;

FIG. 21 is a timing diagram showing the relationship of the various parts of the machine during one complete machine cycle.

Referring now to the drawings wherein the showings are for the purpose of illustrating the preferred embodiment of the invention only and not for the purpose of limiting same, FIG. 1 shows the overall arrangement of the body making machine A comprising drive assembly B, feeding mechanism C, forming and tack welding assembly D, and line welding assembly E.

THE MACHINE IN GENERAL Basically, the machine of the present invention comprises apparatus designed to take flat precut rectangular sheets of aluminum and form them into a tubular can body with a longitudinally extending overlapped and welded side seam.

A conventional sheet feeding mechanism takes blanks of aluminum which have been precut to the proper size and feeds them along the feed table in spaced relationship. When the blanks reach a point within'forming arch and tack welding assembly 400, they are positioned on a cylindrical forming horn with their longitudinal centerline extending generally along the top of the horn and the opposite halves of the blank extending horizontally outward. A clamp is then actuated to clamp the blank firmly to the forming horn along its longitudinal axis. Next, a pair of forming wings move down to deform the outwardly extending halves of the blank about the forming horn. These wings are actuated so that one wing wraps one half about the forming horn slightly ahead of the half wrapped by the other wing. Thus, when the halves of the blank have both been wrapped around the forming born, the edge portion of one half is overlapped relative to the edge portion of the other. The forming wings are then maintained tightly clamped, for a predetermined interval, about the deformed blank and the forming horn. Subsequently, a tack welding ultrasonic welder is moved upwardly into contact with the longitudinal ends of the overlapped blank portions and actuated to tack weld the ends of the blank. After the ends have been tack welded, the welder is withdrawn from its position against the blank, and the forming wings and the blank clamp are retracted. At this time, the partially welded blank or body is moved along the horn to a position within the line or seam welding arch 500. A second clamp is then actuated to reclamp the partially welded can body tightly against the forming horn. Simultaneously, a pair of mass blocks, comprising large blocks formed of copper or similar material having an end surface shaped to conform to the sidewalls of the can blank and forming horn, are actuated inwardly and tightly grip the can. These blocks serve to absorb vibrations caused when the main line welding apparatus is actuated into position against the overlapped seam on the side of the can. When the blank has been tightly clamped by the second clamp and the mass blocks, the line welding ultrasonic welding apparatus is moved upwardly and a welding tip contacts the entire length of the overlapped seam. The welding apparatus is then actuated and completely welds the side seam of the can. After this seam has been welded, the welding apparatus is withdrawn and the mass blocks and second clamp retracted. The finished can body is then ejected from the end of the forming horn onto any convenient conveying system.

Drive Assembly B FIGS. 2 and 3 show in detail the main drive assembly of the machine. The power necessary to drive the machine is supplied from a conventional electric motor mounted to one side of the main base frame 10. This motor drives the machine through a variable pitch pulley-102 and belt 104 connected to the main drive pulley 106. Rotation of pulley 106 causes rotation of an intermediate gear 108 keyed'to a shaft carried in suitable bearings in the right hand end of main base frame 10.

A main drive shaft 111 extends centrally through the base frame 10 and is driven from gear l08 by a gear 110 keyed to the end of the shaft. Keyed to shaft 11' at spaced positions therealong are

cams

502, 402 and 204. These cams actuate the line welder, the tack welder and the forming horn expander, respectively. Also carried by shaft 111 are a bevel gear 202 and a crank 254 which actuate the suction cup and feed bar assemblies.

Gear 110 which drives main shaft 111 also drives intermediate gear 112 which is drivingly connected with gear 113 keyed to lower outer drive shaft 114. Outer drive shaft 114 is connected through an adjustable coupling to a right angle drive 116. The output shaft of right angle drive 116 extends vertically upward through the machine and serves to drive one of the forming wings in a manner subsequently to be described. A second outer drive shaft is also provided. This shaft 120 is driven from a gear 118 keyed thereto and drivingly connected with intermediate gear 108. Shaft 120, like shaft 114, is connected through an adjustable coupling 122 to a second right angle drive 124; The output shaft of right angle drive 124 likewise serves to drive the other forming wing. Also carried by shaft 120 and keyed thereto are sprockets 570 which serve to drive the mass block actuating mechanism and the

blank clamp assemblies

600 and 650.

Feeding Mechanism C retaining rings 212. Bearing spacers 213 are positioned between the bearings 209.

Keyed to the upper end of shaft 208 is a disc crank 216. Rotation of disc crank 216 causes the feed bar drive slide 222 to be reciprocated in slideway 226 through a connecting rod 218 extending between disc crank 216 and a pin or bolt 228 extending from the lower slide portion 224 of the feed bar drive slide 222. An upper half 230 of the An upper half 230 of the drive slide is connected to the lower slide portion 224 by screws 231. This upper half carries a feed bar connector 232. This connector is mounted on themember 230 by a pair of bolts 233 and a bar nut 234. Bolts 233 extend through elongated openings in the connector member 232, thus permitting the connector member to be adjusted longitudinally of the upper half of the drive slide by an adjusting screw 235.

A conventional feed bar 240, having spring fingers 241 carried thereby, is connected to the topof connector 232. The feed bar 240 extends substantially the entire length of feed table 260 and acts to move the flat can blanks therealong.

As best shown in FIGS. 1 and 2, means are provided to feed can blank sheets 246 one at a time to the feed table 260, where they are then moved along in spaced relation by the feed bar 240. The means to feed the can blanks to the feed bar and feed table comprise a conventional vacuum cup feed as sembly 248. This assembly comprises a pair of vacuum cups 250 which are reciprocated up to the bottom of the stack of aluminum can blank sheets 246 carried in the stack frame 245. Downward reciprocation of the vacuum cups causes the bottom can blank to be removed from the stack assembly and carried down to the feed table 260. The means for supplying,

vacuum to the vacuum cups 250 comprises a vacuum line 251 controlled by a cam operated valve 252. Vacuum is supplied to this line, and thus to the vacuum suction cups, from any convenient source of vacuum. The means for reciprocating the vacuum cup assembly in timed relation with the feed bar assembly comprises a crank 254 carried on the left hand end of main drive shaft 211. This crank is connected through a connecting rod 256 to the suction cup carrying slide 258.

After the can blanks 246 have been deposited on feed table 260, they are moved to the right in spaced relationship by reciprocation of feed bar 240. Means .are provided to maintain the can blanks snugly down against the top of the feed table and thus cause the spring loaded fingers 241 to be forced downwardly during the leftward reciprocation of the feed bar. These means comprise a friction bar assembly 262, best shown in FIG. 1. This assembly includes a main support arm 263 which is pivoted at its right end 264 to the forming arch frame 400. A spring latch mechanism 265 is used to maintain the support arm 263 in its lowered position. Carried from the bottom of arm 263 are a pair of friction bars 266. These bars are biased downwardly by springs not shown, and maintain the can blanks snugly against the top of the feed table 260. Thus, when the feed bar 240 is reciprocated to the left, each of the spring fingers 241 is forced downwardly by contact with the blank and spring up into position after passing the blank. Reciprocation of feed bar 240 to the right, then causes the can blanks to be moved to the next position.

When the blanks have reached the right end of the feed table, approximately the position indicated by reference numeral 261 in FIG. 2, they are engaged by extractor bar 270 which is carried in the forming horn assembly 275. As best shown in FIG. 13, extractor bar 270 is constructed similar to feed bar 240 and has a plurality of spaced spring-loaded fingers 272 carried therein. Reciprocation of the extractor bar to the left causes the fingers to be depressed as they pass under the can bodies and spring up after passing thereunder. Thus, when the bar is then reciprocated to the right, the spring fingers contact the rear of the can body and move it outwardly along the forming horn. As shown in FIG. 4, extractor bar 270 is connected to the end of feed bar 240 by bolts 27]. Thus reciprocation of feed bar drive slide 222 causes the feed bar 240 and the extractor bar 270 to be moved together as a unit.

Forming I-Iorn Assembly As best shown in FIG. 4, forming horn assembly 275 is mounted on the right end of bed plate frame 200 by a mounting stand 276 connected to the bed plate by a screw 277. The horn base member 278 is connected to the mounting stand 276 by bolts or screws 279. As shown in FIG. 14, a semicylindrical portion 280 extends from the horn base 278. As shown in FIGS. and 16, this semicylindrical portion 280 forms the lower half of the forming horn in the forming station portion of the horn. The upper half of the horn at this section is formed by a semicylindrical portion 281. Portion 281 is connected to the lower half 280 by screws 282 and springs 283. This allows the upper half 281 to be moved away from the lower half 280, thus permitting the forming station section of the forming horn to be expanded and contracted. Means for moving the upper half away from the lowerhalf and expanding the horn include a cam follower member 284 which is screwed to the upper half member 281 by a pair of screws 285. An expander pin 295 serves to expand and contract the horn by cooperating with the cam follower in a manner to subsequently be described.

Connected to the right hand end of portion 280 is a cylindrical section 286. This section constitutes an idler station between the forming and line welding stations. A plurality of outwardly biased inserts 288 frictionally engage the inner surface of the formed and tack welded can blank coming from the forming station. As best shown in'FIG. 17, section 286 is connected to section 280 by a pin 287 which extends through an opening formed in section 286 and through a corresponding relieved portion formed in the right hand end of section 280. Extending from the right hand end of the cylindrical section 286 and formed integrally therewith is a semicylindrical portion 289. Portion 289 forms the lower half ofthe line welding station portion of the forming horn. A semicylindrical portion 290 is connected to section 289 by screws and springs in the same manner as the upper half 281 of the forming station portion of the horn. This permits the forming horn to be expanded at the welding station section in the same manner as at the forming station section.

An end cap 291 is connected to the end of the horn and has a roller 294 carried by a pin 292 mounted in its lower side. As shown in FIG. 10, this roller contacts a second roller 526 carried on a bracket 525 extending from the side of the welding arch frame 500. This provides support for the end of the forming horn while permitting the formed can bodies to pass off the end of the horn.

A plurality of hardened steel inserts 293 are positioned in a longitudinally extending slot on the lower portion of the forming horn. These inserts are notched or relieved so as to receive the overlapped end portions of the can blank after it has been wrapped around the forming horn by the forming arms. Further, these inserts form a hardened surface against which the overlapped joint is pressed by the ultrasonic welding tips during the welding operation.

The means for expanding the forming station section and the welding station section of the forming horn comprise an expander pin 295 which extends axially throughout the length of the forming horn and has a plurality of camming surfaces 296 formed thereon. Reciprocation of the expander pin causes the camming surfaces 296 to contact corresponding surfaces formed on the cam followers 284 carried in the upper sections of the

horn forming members

281 and 290.

The means for reciprocating the expander pin at the proper time during the cycle are best shown in FIG. 4. These means include a cam 204 keyed to main drive shaft 111. A pair of cam followers 297 contact the outer surfaces of cam 204 and cause the follower frame 298 to be reciprocated vertically. A connecting rod, having an adjustable turnbuckle 299 therein, is connected to the upper portion of the follower frame 298 by a bolt or pivot pin 300. The upper end of the connecting rod is connected to the lower arm 304 of rocker arm assembly 302 by a bolt 301. Rocker arm assembly 302 is pivotally mounted in bed plate frame 200 by a pivot pin or bolt 303. The upwardly extending arm 305 of the rocker arm assembly 302 is connected by a link 306 to the expander pin drive slide 309. Link 306 is connected at its right end to the arm 305 by a bolt 307 and at its left end by a bolt 308 to an extension 310 which extends downwardly from the drive slide 309. Drive slide 309 is carried in a slideway 311 mounted on the bed plate frame 200 by screws 312. The right end of the drive slide is connected to expander pin 295 by screws 313. Thus, it can be seen that rotation of main drive shaft 111 causes the drive slide 309 and expander pin 295 to be reciprocated horizontally thus expanding and contracting the horn at the proper time during the cycle of the machine.

Forming Arch Assembly Forming arch assembly D is best shown in FIG. 8. This assembly comprises a main frame 400 of generally U-shaped configuration connected at its leg ends to base 10 by bolts 401.

A forming wing assembly 404 is carried in the upper portion of frame 400. As best shown in FIG. 9, this assembly comprises a left forming wing 406 and a right forming wing 408, both pivotally mounted from a pin 409 carried in the lower end of support bracket 410. The interior forming

surfaces

405 and 407 of the forming wings are shaped 'to conform to the outer surface of the forming horn. The blade portions 403 carried on each forming wing are positioned such that with the wings in their closed position the overlapped seam 249 is uncovered leaving space for contact by ultrasonic welding tip 430.

The wings are oscillated from an open position, shown dotted,to the lower closed position. Prior to the downward oscillation of the wings, a can blank 246 has been moved into position on the forming horn. Feed bar 240 in conjunction with outer edge guides 413 move the blank onto the forming horn, where it is clamped along an axially extending contact band by clamp 601 in a manner to be subsequently described. With the blank thus firmly clamped to the forming horn, the forming wings are oscillated downwardly forming the blank around the forming horn.

The means for driving the wings comprise connecting

rods

411 and 412 moved by oscillation of

arms

419 and 421 driven by oscillating drives 418 and 420 (see FIG. 8).

These drives are conventional oscillating drives, such as those sold by the Ferguson Machine Company of St. Louis, Missouri. 1n the particular embodiment of the present invention under consideration, the drives are designed to have a 30 oscillation. Further, as can be seen from the timing diagram of FIG. 21, during an 80 portion of the machines cycle the drives function to move the arms to their upper open position.

For an additional 80 portion of the cycle the arms are held open, and then moved to a closed position during a third 80 portion. They are then maintained closed during the final 120 portion of the cycle.

Because of the necessity of overlapping the edges of the can blank around the bottom of the forming horn, the left forming wing, as viewed in FIG. 9, is caused to move downward approximately ahead of the right forming wing 408. This permits the left-hand portion of the can blank to be in position at the time the right-hand edge is wrapped downwardly around the forming horn.

The oscillating drives 418 and 420 are driven from the lower

outer drive shafts

120 and 114. As can be seen, a pair of vertically extending

shafts

424 and 422 are connected by suitable couplings to the output ends of the right angle drives 116 and 124 and to the input shafts of the oscillating drives.

Tack Welding Assembly After the can blank has been wrapped about the expanded forming horn and its ends are in their overlapped position as shown in FIG. 9, an ultrasonic welding apparatus is actuated upwardly against the opposite longitudinal ends of the overlapped seam and tack weld it. The horn can then be contracted and the formed can body moved to the idle station and then to the line welding station where the seam is welded throughout its length.

Ultrasonic welders are comparatively well known and their construction and operation is described, for example, in U.S. Pats. No. 2,946,119, 3,002,270, and 3,056,192. Broadly they consist of apparatus which produces a high frequency magnetic field. that causes rapid expansion and contraction of magnetostrictive transducer connected by a coupler member to a welding tip. The expansion and contraction of the transducer produces elastic vibrations in the coupler member, and consequently, the welding tip. When the welding tip is forced under substantial clamping pressure against a weldment, the high frequency vibrations cause dynamic shearing stresses to be produced in the contacting portions of the weldment. This produces plastic deformation at the interface surfaces of the weldment. Any surface films or oxide coatings present on these face surfaces are shattered and a weld is achieved between the interfaces without prior surface treatment, fluxes, etc. The usable range of vibratory frequencies is generally considered to be between 59 and 300,000 cycles per second, with the optimum being between 5,000 and 40,000 cycles per second. The clamping pressure can vary substantially, but needs to be sufficient to hold the interface surfaces of the weldment firmly in contact.

In the preferred embodiment of the present invention an ultrasonic weld assembly 425 is shown positioned immediately below the forming horn at the forming station section. As shown in FIG. 5, this welder comprises a transducer housing 428 carried from a bracket 426 which extends from the side of the forming arch frame 400. The electrical equipment necessary to produce expansion and contraction of the transducer in the housing is not shown but would be as described in the aforementioned U.S. Pats. Housing 428 is pivotally mounted on bracket 426 by pins or bolts 427. Extending from the right side of the housing 428 are a pair of coupler arms 429. A relatively rigid welding tip 430 is carried at the end of each of the coupler arms 429. As shown in FIG. 9, these welding tips have a generally pointed upper surface which contacts the overlapped edges of the aluminum can blank and transmits the high frequency vibrations to the seam.

The means to move the arms up into welding position and apply the necessary clamping force between the welding tip and the overlapped blank edges comprise a'spring barrel 432 shown in FIG. 8. This spring barrel is designed so that when the arms are moved upwardly approximately pounds of clamping force is applied to the joint between each welding tip and the forming horn.

Means are provided for moving the spring barrel up into clamping position. These means include a spring barrel support 434 carried on pivots 439 at the end of arms 436 supported for oscillating movement from the forming arch frame 400 by pivots 438. Cam 402 keyed to drive shaft 111 acts against a cam follower 440 rotatably mounted on the bottom portion of the support 434. Cam follower 440 is maintained continuously in contact with the earn 402 by a spring 442 which is connected between base frame 10 and the right hand end of lower arm 436. Thus, it can be seen that spring barrel 432, and consequently, welding tips 430 are moved into welding position at the proper time during the cycle in response to rotation of the main drive shaft 111.

After the formed can body has been tack welded by the tack welding assembly 425, the horn is contracted and the blank clamp, the welding assembly, and the forming wings moved away from the horn. The tack welded can body is then moved by extractor bar 270 to an idle position intermediate the forming position and the line weld position. The can body at the idle position from the previous tack welding operation is simultaneously moved to the line welding station position on the forming horn. At the line welding station, the overlapped seam is welded throughout its extent.

MAIN WELDING ARCH ASSEMBLY E The main welding arch assembly E is best shown in FIG. 10. This assembly comprises a main frame 500 of generally U- shaped configuration connected at its legends by bolts 501 to base frame 10.

Carried from frame 500 is the main line welding assembly 503. This welding assembly is an ultrasonic welder and functions in the manner previously described with reference to the tack welder. As shown in FIG. 5, the assembly comprises a transducer housing 508 mounted for pivotal movement about pivots 506 carried from brackets 504 mounted at the side of main frame 500. Extending from the right side of housing 508 are live coupler arms 510. These arms carry an elongated welding tip 511 adjacent their outermost end. Welding tip 511 is formed to extend throughout the length. of the overlapped can seam and securely weld the overlapped portions together.

The means for moving the welding tip 511 into its welding position at the proper time during the cycle comprises an arrangement similar to that described previously with regard to the tack welding assembly. In particular, these means comprise a spring barrel 512 designed to produce approximately 2,750 pounds of clamping force between the formed can and the welding tip 511. This spring barrel is carried on a spring barrel support 514 which is mounted for vertical movement from arms 516 by pivots 520. Arms 516 are pivotally mounted by pivots 518 carried in the left-hand side offrame 500. A cam 502 keyed to main drive shaft 111 acts against a cam follower 522 carried in the bottom of support 514 thus serving to force the welding tip vertically into engagement with the formed can at the proper time during the cycle. A spring 524 extending between the right-hand end of lower arm 516 and base frame 10 maintains cam follower 522 continuously in contact with cam 502.

Because of the tremendous vibrations produced during the line welding operation, means are provided to dampen these vibrations and securely clamp the tack welded can blank to the forming horn. These means comprise a pair of mass blocks 530 and 531, each of substantial size and having a clamping surface 533 which extends substantially the entire length of the can blank. In the preferred embodiment, these mass blocks are formed of copper and are reciprocated into engaged relationship with the tack welded can blank prior to the welding operation. They are then held firmly in engagement with the can and forming horn throughout the welding operation.

As shown in FIGS. 10 and 11, mass blocks 530 and 531 are mounted for horizontal reciprocation in a slideway 532 carried from the under surface of the top portion of the frame 500. Mass block 530 is moved horizontally by a crank arm 536 which is carried in a suitable bearing 538 in frame 500. A slot formed in the lower portion of arm 536 engages a pin connected to the left-hand end of mass block 530. As shown in FIG. 12, arm 536 is connected to an upwardly extending arm 534 driven by a connecting rod 542. The right-hand end of connecting rod 542 is connected to a cam follower frame 548 having a pair of follower cams 55.0. carried therein. Cam follower frame 548 is mounted in a pair of slideway forming members 552 on the right-hand side of frame 500. A cam 554 serves to reciprocate the cam followers horizontally during its rotation. Shaft 556 on which cam 554 is mounted extends through frame 500 and out the opposite side.

Mounted at the other end of shaft 556 is a second cam 558 which serves to reciprocate cam follower frame 560 through contact with followers 562 carried thereon. The cam follower frame 560 is mounted for horizontal reciprocation in the same manner as previously described cam frame 548, and is connected by a connecting rod 564 to crank arm 544 carried in bearing 540 shown in FIG. 10. A second downwardly depending crank arm 546 is connected through its slotted lower end to a pivot or pin carried by mass block 531. In this manner, rotation of shaft 556 causes mass blocks 530 and 531 to be simultaneously reciprocated into and away from the forming horn.

The means for rotating shaft 556 and earns 554 and 558 in timed relation with the remaining parts of the machine comprise a sprocket 566, keyed to the shaft 556, and driven by a chain 568 which extends around sprocket 570 carried on the lower outer drive shaft 120. Chain 568 extends around lower sprocket 570 and an idler sprocket 572 carried on a slide mounted for adjustment in the upper portion of the frame 500. Chain 568 also extends around a sprocket 574 positioned centrally of frame 500. This sprocketis keyed to a shaft 576 mounted in suitable bearings in frame 500 and having its end portions extending beyond opposite sides of the frame.

Mounted at opposite ends of the shaft are

adjustable cams

578 and 580. These cams serve to drive the clamping mechanism used to clamp the can blank at the forming and welding stations on the forming horn.

Blank Clamp

Assemblies

600 and 650 As best shown in FIG. 6, a clamping assembly 600 and a clamping assembly 650 are provided at the forming arch and welding arch portions of the machine, respectively. These clamp assemblies hold the blank or partially formed can tightly in position on the forming horn while the forming and welding operations are carried out.

Clamp assembly 600 comprises a clamp member 601 carried on the lower portion of clamp and forming wing support slide 602. This support slide is mounted-for reciprocation ver tically in the lower end of support 410. Springs 607 serve to maintain clamp and forming wing support slide 602 biased upwardly by acting against a bar member 604 which is screwed to the top of the slide 602 by screws 606. Means for forcing the clamp downwardly comprise a wedge member 610 which is mounted to be freely reciprocable vertically but prevented from moving horizontally by plates 612 carried on support 410 at opposite ends of the wedge member. A reciprocating slide wedge 614 is horizontally reciprocable between the upper wedge surface of member 610 and a wear plate 616 mounted in the support 410 by screws 618. As can be seen, movement of member 614 to the left causes the clamp and the clamp and forming link support slide to move downwardly, while movement of member 614 to the right permits the clamp and slide to move upwardly under the bias of springs 607.

The means for moving the slide wedge 614 comprise a crank arm 620 carried on a support bracket 622 which is mounted on the welding arch frame 500. Crank 620 is mounted for pivotal movement about a pin 624. A bolt or pin 626 carried in the lower arm of the crank arm extends through the right hand end of slide wedge 614 and is loosely received in an elongated opening formed therein. The upper arm of crank arm 620 carries a cam follower 628. This cam follower is biased against the camming surface of rotary cam 578 by a spring 630 which extends between the lower arm and the support bracket 622. An adjusting stud 632 is provided to vary the biasing force on the arm. v i

A similar clamp assembly 650 is provided at the welding station on the forming horn assembly 275. This clamp assembly comprises a clamp member 651 having an inclined upper wedge surface contacted by a wedge surface on horizontally reciprocating slide wedge 654. Clamp member 651 is permitted to have vertical movement but is restrained against horizontal movement by a pair of plates 652 which extend across its ends and are connected at their ends to the welding arch frame 500. Pins extending through member 652 are received in openings formed in the ends of clamp member 651. Thus, reciprocation of horizontal slide wedge 654 to the left between clamp 651 and wear bar 656 causes the clamp to be forced downwardly against the can at the welding station on the forming horn assembly.

The means to reciprocate slide wedge 654 comprises a crank arm 660 carried on a pivot pin 661 supported by a support bracket 664 mounted onthe right-hand side of welding arch frame 500. Slide wedge 654 is connected to arm 660 by a pivot 662 received in a slotted opening in the right-hand end of slide wedge 654. A cam follower 666 is carried by the upper arm of crank 660. This cam follower is biased into engagement with the camming surface of cam 580 by a spring 668 extending between the bracket 664 and the upper arm of the crank 660. An adjusting stud or bolt 670 is provided to vary the bias on the arm.

Thus, in view of the above, it can be seen that rotation of shaft 576 by chain 568 (see FIG. 12) causes the

cams

578 and 580 to rotate and actuate the

clamp assemblies

600 and 650 into and out of clamping engagement with the can blanks or partially formed cans on the forming horn assembly 275. As previously mentioned, chain 568 is driven by a sprocket 570 keyed to the lower outer drive shaft 120. Thus, the clamps are driven in timed relation with the remaining portions of the machine.

OPERATION FIG. 21 is a timing diagram showing the sequence of operations for the machine for one complete cycle of the main drive shaft 111. The various time periods and cycle points set forth could, of course, vary. Factors such as the size of the can being formed, the thickness of the blanks used, the power of the ultrasonic welders, etc., could make other timing cycles more desirable. Therefore, it is to be understood that the following is not to be considered limiting, but as merely descriptive of one satisfactory timing cycle, and given .only to aid in understanding the machines operation.

Assuming that the welds have just been completed and the machine has rotated to approximately the l7V2 point in its cycle, it can be seen that the mass blocks at the line weld station are in the clamped position and the horn at both the forming and weld stations is expanded. The forming wings are closed tightly about the can blank formed about the mandrel at the forming station. The

blank clamp assemblies

600 and 650 are both in their downward or clamped position. At this time, the feed bar has just begun its forward or feeding movement. After the machine has rotated to its 20 position, the mass blocks at the line weld station are moved to their open or unclamped position and the

blank clamp assemblies

600 and 650 are also moved to their open or unclamped position. Subsequently, at the 30 point in the cycle, both the tack welder and the line spot welder begin moving away from the forming horn. At this time, the spring fingers on the feed bar contact the blank and begin moving it forward to its next position on the forming horn. At approximately the time the spring fingers contact the blank, the forming wings begin moving upwardly away from the forming horn. During approximately the next l40 portion of the cycle, the blanks are moved along the forming horn to their new position and the completed can body at the line weld station of the forming horn is ejected. At this time, approximately the 180 point of the machine cycle, the horn is expanded at both the forming section and the line welding section. lmmediately thereafter, at the 190 point in the cycle, the mass blocks have moved in and clamped against the tack welded and formed body positioned at the line weld station. Simultaneously, the

blank clamps assemblies

600 and 650 have moved into clamping position. At this time, the forming wings are moving downwardly, with the left hand wing moving downwardly ahead of the right hand wing. This causes the blank at the forming section of the horn to be wrapped tightly about the forming horn with its ends overlapped. At approximately the 195 position, the line weld assembly is moved upwardly against the seam of the tack welded and formed can positioned on the forming horn at the line weld station. For the next 180 of the machine's cycle, the seam is welded by the line weld assembly. At the 260 point in the cycle, the forming wings have completely formed the blank about the forming horn and are in their closed position. Immediately thereafter at the 265 point in the cycle, the tack weld assembly is moved in andthe ends of the formed blank tack welded.

During the time that the forming and welding operations are taking place from the 180 point in the cycle to the 350 point in the cycle, the feed bar is moving rearwardly into position to again move the blanks and formed cans along the feed table and the forming horn. When the machine has rotated to the before-mentioned starting point, the above-described sequence of operations again takes place Thus, it can be seen that a body forming machine has been provided which is capable of producing a large number of can bodies having an overlapped welded seam with none ofthe objectionable features previously found in welded aluminum can bodies.

The invention has been described in great detail sufficient to enable one skilled in the art of can making to duplicate the invention. Obviously modifications and alterations of the preferred embodiment described will occur to others upon a reading and understanding of this specification, and it is our intention to include all such modifications and alterations as part of our invention insofar as they come within the scope of the appended claims.

We claim:

1. An apparatus for forming a generally cylindrical can body from a metal blank having opposed edges and an intermediate portion between said edges, said intermediate portion defining two oppositely extending blank portions terminating in said edges, said apparatus comprising: a forming member having an outer generally cylindrical surface and a longitudinal axis; means for clamping said intermediate portion against said surface along a contact band generally parallel with said axis; a first movable member for wrapping the first of said blank portions around said forming member is-a first circumferential joint; and, means for moving said welding means against said I joint only when said blank is stationary and clamped to said forming member along said axial contact band.

2. The apparatus as defined in claim 1 including drive means for moving said first and second movable members,

said drive means including means for driving said first mova ble member to wrap the first of said blank portions about said forming member before said second movable member has wrapped the second on said blank portions about said forming member.

3. The apparatus as defined in claim 1 wherein said ul-, trasonic welding means includes a welding tip having a length 1 substantially equal to the length of said overlapped joint and coterminous with said joint.

4. The apparatus as defined in claim 1 wherein said means for moving said ultrasonic welding means against said overlapped joint is operable while said first and second means are in engagement with said first and second blank portions.

5. The apparatus as defined in claim 1 wherein said forming member includes means for moving said outer surface radially to thereby change the effective periphery of said surface.

6. The apparatus as defined in claim 1 wherein said forming member includes means for moving said blank along said cylindrical surface after said overlapped joint has been welded.

7. The apparatus as defined in claim 1 wherein said forming member has first and second longitudinally spaced sections, and means for moving said first and second sections radially to change the effective periphery of said cylindrical surface.

8. The apparatus as defined in claim 7 wherein said first and second movable members are positioned to wrap said blank about said first section.

9. The apparatus as defined in claim 8 including means for moving said blank from said first section to said second section.

10. The apparatus as defined in claim 9 wherein said ultrasonic welding means includes a first ultrasonic welding means positioned adjacent said first section and a second ultrasonic welding means positioned adjacent said second section.

11. The apparatus as defined in claim 10 wherein said first ultrasonic welding means includes means for welding spaced points of said overlapped joint, and said second ultrasonic welding means includes means for welding said overlapped joint throughout its length.

12. The apparatus as defined in claim 10 including means for clamping said blank at said second position, and vibration dampening means for engaging said blank at said second position.

13. The apparatus as defined in claim 12 wherein said first ultrasonic welding means includes means for welding spaced points of said overlapped joints, and said second ultrasonic welding means includes means'for welding said overlapped joint throughout its length.

14. An apparatus for forming a generally cylindrical canbody from a metal blank having opposed edge portions and an intermediate portion defining two oppositely extending blank portions terminating in said edge portions, said apparatus comprising: a forming member having an outer generally cylindrical surface and a longitudinal axis, said cylindrical surface comprised of a plurality of relatively movable portions; means for moving at least one of said movable portionsradi ally of said longitudinally axis between a first position where the effective periphery of said generally cylindrical surface is said engaged edge portions for joining said engaged edge portions while said blank is wrapped about said generally cylindrical surface; and, clamp means for maintaining said blank clamped to said cylindrical surface while said welding means 5 joins said edge portions.

15. The apparatus as defined in claim 14 including means for moving said blank along said generally cylindrical surface.

Claims

1. An apparatus for forming a generally cylindrical can body from a metal blank having opposed edges and an intermediate portion between said edges, said intermediate portion defining two oppositely extending blank portions terminating in said edges, said apparatus comprising: a forming member having an outer generally cylindrical surface and a longitudinal axis; means for clamping said intermediate portion against said surface along a contact band generally parallel with said axis; a first movable member for wrapping the first of said blank portions around said forming member is a first circumferential direction; a second movable member for wrapping the other said blank portions around said surface in a second circumferential direction, said first circumferential direction being opposite to said second circumferential direction and said edges being spaced apart sufficiently to form an elongated overlapped joint when said blank portions are wrapped about said forming member; and ultrasonic welding means movable against said overlapped joint while said blank is on said forming member for welding at least portions of said overlapped joint; and, means for moving said welding means against said joint only when said blank is stationary and clamped to said forming member along said axial contact band.

2. The apparatus as defined in claim 1 including drive means for moving said first and second movable members, said drive means including means for driving said first movable member to wrap the first of said blank portions about said forming member before said second movable member has wrapped the second on said blank portions about said forming member.

3. The apparatus as defined in claim 1 wherein said ultrasonic welding means includes a welding tip having a length substantially equal to the length of said overlapped joint and coterminous with said joint.

13. The apparatus as defined in claim 12 wherein said first ultrasonic welding means includes means for welding spaced points of said overlapped joints, and said second ultrasonic welding means includes means for welding said overlapped joint throughout its length.

14. An apparatus for forming a generally cylindrical can body from a metal blank having opposed edge portions and an intermediate portion defining two oppositely extending blank portions terminating in said edge portions, said apparatus comprising: a forming member having an outer generally cylindrical surface and a longitudinal axis, said cylindrical surface comprised of a plurality of relatively movable portions; means for moving at least one of said movable portions radially of said longitudinally axis between a first position where the effective periphery of said generally cylindrical surface is enlarged, and a second position where the effective periphery of said generally cylindrical surface is contracted; means for wrapping said blank about said generally cylindrical surface while the effective periphery of said generally cylindrical surface is enlarged, said wrapping means including means for moving said edge portions into engagement along a line on said generally cylindrical surface generally parallel to said axis; ultrasonic welding means movable into engagement with said engaged edge portions for joining said engaged edge portions while said blank is wrapped about said generally cylindrical surface; and, clamp means for maintaining said blank clamped to said cylindrical surface while said welding means joins said edge portions.