US2679816A - Apparatus for drawing seamless cans - Google Patents

Description

June 1, 1954 M. E. MOORE APPARATUS FOR DRAWING SEAMLESS CANS 5 Sheets-Sheet 1 Filed May 20, 1950 INVENTOR. iflark 9 /7Z0076 BY June 1, 1954 M. E. MOORE 2,679,816

APPARATUS FOR DRAWING SEAMLESS CANS Filed May 20, 1950 5 Sheets-Sheet 2 ilzczr'k '8. [Icons June 1, 1954 M. E. MOORE 2,679,816

APPARATUS FOR DRAWING SEAMLESS CANS Filed May 20, 1950 5 Sheets-Sheet 5 June 1, 1954 M. E. MOORE 2,679,316

APPARATUS FOR DRAWING SEAMLESS CANS 5 SheetsSheet 4 Filed May 20, 1950 I N VEN TOR.

i fczr 5. Wanna June 1, 1954 E, MOORE 2,679,816

APPARATUS FOR DRAWING SEAMLESS CANS Filed May 20, 1950 5 Sheets-Sheet 5 .511 2:92 JZzm INVENTOR.

Patented June 1, 1954 APPARATUS FOR DRAWING SEAMLESS CANS Mark E. Moore, Chicago, Ill., assignor to Williston Seamless Can (30., Inc., Williston, N. Dak., a

corporation of Delaware Application May 20, 1950, Serial No. 163,117

1 Claim. 1

The present invention relates to apparatus for drawing seamless cans, and is particularly concerned with improved devices by means of which. seamless cans made out of suitable metal, such as steel, aluminum, brass, copper, or any other suitable material, may be drawn from circular discs in a single stroke.

One of the objects of the invention is the provision of improved apparatus by means of which seamless cans may be drawn more quickly and more economically than by the methods of the prior art, for the reason that the present apparatus requires a single stroke with no intermediate handling of the product so as to reduce the labor and increase the output.

Another object of the invention is the provision of an improved die construction by means of which seamless cans may be drawn at a single stroke and discharged from the machine at a high rate of production, such as, for example, about fifty cans per minute.

Another object is the provision of an improved die construction which has novel methods of lubrication, and otherwise reducing the friction between the can parts and the parts of the die so that a maximum number of perfect cans may be drawn with a minimum number of imperfect or torn'cans.

Another object is the provision of improved apparatus by means of which the amount of power required to operate the dies is substantially reduced, while still forming substantially perfect seamless cans at a single stroke and at a high rate of production per minute.

- Another object is the provision of improved apparatus for drawin seamless cans which involves a plurality of successive operations upon the blank or can, but in which these operations are so quickly performed in succession that the metal of which the can is formed is still hot from the first and earlier operations, when the second or succeeding operations are performed, so that the metal does not have an opportunity to become hardened by cooling in between operations; and the work, which is performed in drawing the can and which is ordinarily dissipated in raisin its temperature, is greatly reduced in its total amount so that cans may be drawn more easily with the expenditure of less power.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings of which there are live sheets accompanying this specification,

Fig. l is a side elevational view of the press equipped with the die and other apparatus embodying the invention;

Fig. 2 is a vertical sectional view taken on the plane of the line 22 of Figure 1;

Fig. 3 is a front elevational view of the press of Figure 2;

Fig. 4 is a fragmentary vertical sectional view on a larger scale, showing the parts of the die of Figure 2 on the plane of the line 4-4 of Figure 2, looking in the direction of the arrows and showing a completely formed can at the time of its discharge from the inner post of the die;

Fig. 5 is a fragmentary sectional view taken on the same plane as Figure 4, With the inner post of the die in elevation, showing the parts as they appear after a disc has been fed to the die but before it is gripped by the pressure pad;

Fig. 6 is a view similar to Figure 5, showing the seamless can in the course of its formation, at the time when the inner post of the die has reached the end of the sleeve or punch of the die and the blank has been drawn entirely out of the space between the pressure pad and the face of the die;

Fig. 7 is another view similar to Figures 5 and 6, showing a seamless can in the course of its being drawn and showing the action of the inner post-in the formation of the can after it has passed the lower end of the sleeve or punch;

Fig. 8 is a view similar to Figures 5, 6 and '7, with the parts of the die in the position which they assume when the seamless can has been wholly formed, and the lower forming die has also come into engagement with the bottom of the can to shape the bottom as desired in cooperation with the end of the inner post; and

Fig. 9 is a diagrammatic view showing the conduits and elements required for the hydraulic operation of such a die.

Referring to Figs. 1 to 3, the present apparatus is shown in connection with a hydraulic press, indicated in its entirety by the numeral 2; but I desire it to be understood that the die can be operated mechanically as well as hydraulically.

The press preferably includes a suitable framework, which may consist of a housing 25 joined at the top by horizontal frame portions 22, and joined at a point above the bottom by a bed member 23, which is rectangular in shape and may be square.

The top frame members 22 support a cross head plate 24, against which the hydraulic cylinders may react, and to which they may be attached. This framework may be covered by means of a suitable housing 25, provided with lateral windows 26, 2! for access to the parts of the die.

The housing is generally rectangular, but may have a pair of laterally projecting lower diagonal flanges 28 for housing the discharge opening where the finished cans are discharged.

All of the fixed parts of the framework and housing may be constructed out of suitable steel, and may be secured together by suitable bolts or other fastening means, but are preferably welded together to provide a rigid frame.

Referring to Fig. 4, the movable parts of the die are the pressure pad 29, the sleeve punch 30, and the inner post 3!. Each of these is preferably provided with a separate mechanical or hydraulic means for the application of pressure and for moving these elements.

The pressure pad has a minimum amount of movement, moving upwardly only sufi'iciently to admit the disc-shaped blank 32 (Figure 1) and, therefore, the pressure pad is actuated by means of hydraulic cylinder 33, which is relatively short but powerful.

The plunger or piston 34 of this hydraulic cylinder is connected by means of a pin and slot 35 to a pair of levers 36, the opposite end of which is pivoted at 31 on the frame. Levers 36 are pivotally connected at 38 to connecting links 39, the lower ends of which are pivotally connected to the pressure pad at 40.

Thus the hydraulic cylinder 33, which is carried by cross head plate 24, is adapted to move the pressure plate 29 upward and downward; and when the pressure plate is in its lowermost position it is adapted to place a heavy pressure on the blank 32 to hold it against wrinkling as the blank is drawn from the flat condition and shaped into a can.

For example, the pressure in pounds per square inch placed by the pressure plate upon the blank may be about 100 lbs. per sq. in. The pressure varies, depending upon the thickness of the can and the character of the material of which the can is to be made, and this example is given as a suitable pressure for cans made of 30 gauge steel.

The sleeve punch 30 may be actuated by means of the hydraulic cylinder 4 I, carried by cross head plate 24, and having a plunger or piston rod which is pivotally connected at 42 to a pair of links 43. The links 43 are pivotally connected at 44 to a pair of levers 45, the opposite ends of which are pivotally mounted on the frame at 46 on a suitable pivot bracket 41.

The levers are pivotally connected at 48 to a pair of downwardly extending links 49, which have their lower ends pivotally connected at 50 to a guide plate 5| which supports and guides the sleeve punch 30.

The pressure pad 29 also includes a suitable guide plate 52. These guide plates may be rectangular in shape, and are preferably square and are provided at each of their four corners with upwardly or downwardly extending tubular guides 53 and cylindrical bores 54.

The bed 23 of the press supports a suitable base plate 55 for the die assembly, which base plate carries four upwardly extending, equally spaced and parallel cylindrical guide rods 56. The guide plates 5| and 52, which support the sleeve punch 30 and pressure pad 29 are slidably mounted on the rods 56, and the elongated surfaces in the bores 54 engaging the rods guide the plates with a minimum possibility of binding.

The inner post 3| may be actuated by the cen- Cir trally located hydraulic cylinder 51, carried by the cross head plate 24 and located below at its center between the pairs of levers 36 and 45.

The piston or plunger of the hydraulic cylinder 57 is provided with a connecting rod or connecting rod portion 58, which is fixedly secured to the inner post 3|. For example, connecting rod 58 may have a reduced threaded portion 59, received in a threaded bore 60, and driven home until the annular shoulder 6| on the connecting rod 58 engages the upper plane end of the inner post 3|. Thus the inner post is adapted to be moved and it has pressure applied to it by the hydraulic cylinder 51.

The range of movement of the sleeve punch 30 is determined by its length, which in turn is determined by the length of the can to be formed; and the pressure applied to the sleeve punch by means of hydraulic cylinder 4| varies with different sizes of cans and the gauge and character of metal employed for the can.

The inner post 3| has the greatest range of movement since it moves first with the sleeve punch 30, and later moves down beyond the sleeve punch 30 to complete and discharge the can.

Therefore, the hydraulic cylinder 51 is longer and like the others the pressure applied depends upon the size of can, character, and gauge of metal.

Referring to Figure 9, this is a diagrammatic illustration of the oil and air circuits for the hydraulic cylinders for lubrication and for compressed air supply. For purpose of illustration the valves 62 are shown as being operable by means of suitable cams 61-H, all of which may be mounted upon a single timing shaft.

However, I desire it to be understood that the valves may be actuated automatically by the movement of the parts, such as the pressure pad, the sleeve punch, or the inner post, so that the arrival of these parts at predetermined positions determines the actuation of the valves for moving the next part or parts in the cycle of operation.

Thus the mechanism may be arranged so that when the hydraulic cylinder applies pressure to the blank disc this also actuates the valves 63 and 64 to cause them to begin the movement of the inner post and sleeve punch. Therefore the cams are merely used for purpose of a simplified explanation.

The system includes an oil sump 72 and an oil pump 13, having its inlet extending into the oil of the sump and discharging oil under pressure to a surge tank 14. The surge tank has its discharge pipe 15 depending into the oil which has entrapped air 16 in the space above the oil, so that the compressed air in the surge tank provides a supply of oil at a substantially constant pressure.

The oil supply pipe I5 has branches leading to the three valves 62-64, which have branch return pipes connected to an oil return pipe 11,-returning the used oil to the sump. The valves 62-64 control conduits 18 and 79, and 8|, and

82 and 83, leading to the opposite ends of the hydraulic cylinders 33, 4t and'51, respectively, so that the valves 62-64 may supply oil under pressure to either side of the piston in each hydraulic cylinder to move the parts in either direction as required in the cycle in operation of the die.

The diagram, Figure 9, also includes valve 65, controlled by cam 10, for controlling a conduit 84, leading to a source of lubricant under pressure to supply lubricant to the die. The valve 66,

controlled-by cam H,- controls a conduit 85, providing a supply of suitable air pressure, for the purpose of discharging the cans from the die and for assisting in the drawing of the cans during the cycle of operation of the die.

Lubricant and air supplies are connected by suitable flexible pressure conduits 86, 81 to the inner post 3|, at the threaded bores 88 and 89 at the top of this post. For example, the threaded bore 89 may be for lubricant, and it may communicate with the longitudinally extending bore or conduit 90, which terminates at the lower end of the post 3| in a suitable outlet 9 I, controlled by a ball check valve, spring pressed into closed position by spring 93.

Check valve 92 prevents lubricant or air from going backward in the conduit 90. The conduit 90 preferably communicates with a transverse lubricant conduit 94, which may have a plurality of outlets 95, located just below the piston rin s 96. v

The piston rings are mounted in suitable piston ring grooves in the cylindrical inner post 3| for preventing the loss of lubricant or air upwardly through the clearances between the post 3| and sleeve punch 30.

The threaded bore 88 leads to a longitudinally extending conduit or bore 91 for air, which is provided with a discharge opening 98 at its lower end, controlled by a ball check valve 99, urged into closed position by spring I00.

Check valve 99 aids in maintaining suitable air pressures at times when the air has been shut off at the air valve. The structure of the die assembly is preferably as follows: The bed 23 of the press is provided with a central bore IOI, bordered by a depending tubular portion I02, through which the finished can passes to be discharged. The can in Figure 4 is indicated by I03.

The depending tubular formation I02 supports a can discharge guide I04, comprising a partially cylindrical body I05, provided with laterally projecting, parallel guide flanges I06. The can discharge guide is secured at its attaching flange I01 to the tubular formation I02 by screw bolts I08.

The can discharge guide I04 has an inner cylindrical surface providing a continuation of the cylindrical bore I09, which acts as a guide for the lower pressure plunger IIII, which cooperates with the inner post 3| to form the lower end of the can. The lower end or bottom III of the can is preferably formed with an annular, outwardly projecting, pressed corrugation II2, taking the form of an inner groove partially circular in cross section and an outer rib.

The bottom I I I is also preferably formed with a rib I I3, having an easy bend, which is partially circular in cross section and which extends all around the lower edge of the seamless can projecting downwardly.

The rib II3 approximates in shape and structure the seam which now appears on the bottoms of seamed cans, so that the present seamless can can be gripped more readily or centered and held by can handling machinery, such as a can opener. The upper end of the lower plunger H is, therefore, complementary in shape to the lower surface of the bottom III of the can.

The lower end N4 of the inner post 3| is complementary to the inside of the bottom of the can II I. Therefore, the bottom of the inner post is flatand plane except for the depending annular l sua. '1

The lower plunger I I0 may also be actuated by suitable mechanical or hydraulic means, and it moves up in the cylindrical bore I09, which has a suitable pivoted stop member III pivotally mounted in a slot II8 and having curved stop surface II9 for engaging the bottom of each can and deflecting it out of the housing I05 intothe rectangular trough I20.

The stop member II'I pivots by gravity to the position of Figure 1 or Figure 4, but plunger IIO cams against the beveled surface I2I to move the stop member out of the bore I09 and out of the way of the plunger I I0 as the plunger comes An upward extension I22 on stop member II'I engages the outside of housing I05 and prevents the stop member II! from pivoting farther in a counterclockwise direction from the left. A depending tail I23, below the point of pivot I24, prevents stop member II! from moving too far in a clockwise direction. I

The die supporting plate 55 is suitably secured to the bed 23 by adjustable bolts, not shown, so that its central cylindrical bore I25 may be centrally located above the bore IOI. Base plate 55 has a concentric, circular recess indicated by the annular shoulder I26 for seating the die body I21 in concentric relation to the base plate 55.

Die body I21 may be made of soft steel and comprises a cylindrical metal member formed with a cylindrical bore I28, an annular shoulder I29 and a counterbore I30. Counterbore I30 has suitable clearance with respect to the formed can and is for passing the can and the inner post which supports the can.

Cylindrical bore I28 is for receiving the hardened steel die member I3I, which is tubular in shape and has an outer cylindrical surface I32 fitting in bore I28, with a plane surface engaging the annular shoulder I29.

Hardened die member I3I has a radial pressure flange I 33 seated in a shallow circular recess I34 in the die body I2I to hold the hardened die member I3I in concentric position. Hardened die member I3I is held in its bore I28 by bolts. Ring I35 has an overhanging annular shoulder I36 engaging the top of the radial flange I33 at its outer edge, and serves to locate the blank.

Retaining flange I31 is preferably beveled at I38 on its inner upper corner, but has an inner cylindrical portion I39 which locates and holds the blank disc 32 in proper position. As seen at I40 (Fig. 1), the upper retaining flange I31 is cut away on the feed side of the die to facilitate the entrance of the blank discs 32 from the right in Fig. 1. r

' A suitable feed mechanism, generally indicated at I4I, includes a stack of discs I42 and a chain drive I43, the driving lugs I44 of which project upwardly far enough to engage only one disc 32 and move it to the left, where its motion is continued by lubricating rollers I45, one of which dips into a lubricant reservoir I46 to lubricate the blank.

: Any type of-feed and lubricating mechanism may be employed, and that shown is merely dia-i clearance with respect to the external cylindri calsurface I48 of the sleeve punch 30, which provides space for the can-blank and is proportionate to the thickness et the 1 blank at 'the time it -is partially formed and locatedon "the outside of the sleeve punch 30. l

Belowthe cylindrical-bore portion I' I'I there is an-annular lubricant groove I49 which commum'eates with a throu'gh'bore I 50 in-ithe hardened die member I 3|, which in turn communicates with -an annular groove IBI and a cond'uit 152' in the antibody I21.

*A-branoh conduit from the oilsupply conduit may-also be-conneoted-tothis conduit I 52. The conduits Just referred to supply lubricant to the outside of the partially formed can, the lubricant finding its way i upward into -the bore -I '41; outside of the can and downwardover the frusto conical surface I53, in the"- hardeneddie member I3I, which is immediately -belowtheannular lubricant conduit I49.

"The frusto-conicial surface I53 in the die member I3I is of the same angularity as the beveled surface I 54-on the lowenend of the sleeve punch 30. Above the cylindrical -bore "I4|, in thedlie member -I 3 I there is an annular rectangular groove which may serve as a lubr'icant reservoir for receiving excess "lubricant;-andabove the annular groove 1'55 thereis a cylindrical bore I56 of slightly greater-diameter than the'bore I41. Bore I56 provides relief about the partially formed can blank as it is drawn down into the roundopening' of the-"die member I 3 I At-its upper-"end theopening-in the die member "I3I -is provided witha rounded corner I51, which-has a clearancewith respectto the sleeve punch 30, depending upon 'the-amount'ofdraw that is to be'accomplishedin the can blank at this point.

From the corner -'|5'| the-opening in the die member I3 I becomes gradually larger, having a frusto-conical portion l58down to the-bore I56. Below the I rusto-conical surface I 53, at the lower endof the hardened die member I3I, this member is provided-witha round here |59-leading from -a rounded, annular-"corner I60, and the round bore I59 tapers upwardly and substantially frustoconicar and larger at the bottom to providea relief about the can wall -after it has been'drawn overthe corner I60 of thediem'ember 'I3 I.

- The lower end of the 'die member -'I 3 I may be plane at thelower end I6I, fitting in the bore I28 against the annular shoulder I29. Thesleeve punch 30 comprises a hardened steel tubular member having the cylindrical outer-surface I48 and also-having a cylindricalinner bore 62.

The outer cylindrical surface I48 has a; sliding fit-with :the-b'ore' I63 extending through the pressure -pad Zeand itssupporting plate 52. -At its upper :end, above the pressure pa'dsupporting plate'52; punch sleeve 30 has a radial supporting flange I64 provided with threaded bores for receiving the screw bolts 1'65; by'means of which the sleeve punch is secured to the guide plate 5 I Guide plate 5| has a bore fitting about the upper tubular end of 'the sleeve puneh -flxand guide plate'S'I- hasacounte'rbore I'G'Ffor receiving the radial flange I 64. The internal bore I62 oi' the sleeve punch 30 is cylindrical and has a sliding fit with respeet totheinner post 3 I. V

The inner post- 3| eomprisesa hardened and solid cylindrical steel member attached at its upper end to the connecting rod orjplungerf58. and provided at its lower enewamhe formations for shaping thebottom of the can.

Referring now to Figures 5 to 8-,tl'1ese are views showing the=method=o1makingseamlesscans in azs'ingle stroke operation.

In'Figure 5 the innerpost- 3-I 'the'punch sleeve 30, and the pressurepad '29 have all been raised above the die member lfl, and acircularste'el disc or blank has been fed into the recess which is bounded by the annular-wall- I39. The pressure pad 29'descendsaga-inst the blank 32 first-and clamps it firmly against the die memberl 3 I to hold the blank against wrinkling as it is drawn into can shape.

In the next stepafter this the inner post 3| and sleeve punch tll descend toge'the -the lower end I 4 of the'inner'post being substantially flush with the lower end I68 of the sleeve punchSIl. The-sleeve punch and innerpost act as one solid body-engaging the blank disc 32 and drawingit downward over'the roundedcorner I5'I,*forming a roundpartially formed can'body of the'shape shown in Figure" 6.

As the inner post and sleeve punch descend the edge of the blank 32 is drawn inward underneath thepressure'pad and gradually diminishes in diameter until it has been entirely drawn'from beneaththe pressure'pad. "Whenthe inner po'st 3| and sleeve punch 3|] have arrived at the position of'Figure 6 and are ready'for the second drawing operation, all ofthe'blank should havebeen drawn out from beneath the pressure pad.

The next step in the formation of the can'is its further reduction insize from the'enlarged cylindrical shape 'of Figure 6, to the smaller cylindrical size of the internal post 3|. This is accomplished by stopping the sleeve punch 30 in the position shown Figure 7 and holding "it there with hydraulic pressure while the inner post 3| continues to move downward to draw the partially formed can wall over the annular corner I60, further reducing it insize and elongating the can, a part of which has already been completed in Figure 7.

The'inner'po'st 3| continues to move downward until the entire can has passed the annular corner I60, and the entire can has been drawn into the smaller cylindrical shape whichis complementary to the inner post 3|.

During all of this time the lower bottom shaping plunger III] hasbeen rising, and immediately after the cylindrical wall of the canhas reached its final shape in-Figure 8, the bottom shaping plunger I In comes into engagement withvthe bottom of the can and the bottom is shaped between the lower plunger III) and theupper inner post 3|, as shown Figure 8.

Thereafter the bottom plunger III] is withdrawn-and the can is forced on the lower end of the inner. post 3I by air pressure, but air pressure is not merely'used for discharging the can, and is, like the lubricant, constantly applied to the inner post'discharging out of its lower end into the inside of the partially formed can while the die-is. doing -its work.

The air on' the' inside of the can blank'32, in Figure 6, provides a-powe'rful internal pressure which tends to expand the can slightly and to separate the can walls from the post" 3I'by fluid air so-that the can can be drawn more easily. While the can is being further elongated and diminished insize, as shown in Figure .7, the air under pressure comes out'of'the lower end of the inner post 3| into therein 32 and leaks upward along the sideof the partiallyformed can.

The air cannot pass'the piston ringsilt and, thereforeflit tends to"follow*the inside of the can wall and to go between the can and theoutside of the sleeve punch 30 in Figure '7, tending to space these two surfaces and to enlarge the can so that it is drawn more easily.

When the can is completely formed, as shown in Figure 8, the air pressure still tends to enlarge the can and to permit its discharge oh the lower end of inner post 3| with greater facility, also acting to make the cans slide off.

The lubricant which is suppliedthrough the conduit 90 is delivered first at points just below the piston rings from whence it is forced downward between the inner post and the punch sleeve 30, and leaks upward around the inner sleeve punch 30 inside the can wall.

Other lubricant is supplied outside the can wall at the annular groove I49, lubricating the outside of the can wall just before it is drawn over the annular corner I611. The prelubrication of the blank at its top and bottom as it is fed into the die proviles lubrication between the blank andthe pressure pad, and between the blank and the top of the hardened die member I3l.

When the can has been completed, as 'shown in Figure 8, the lubricant is preferably shut off by its valve to prevent its loss, and as. soon as the can has been discharged from the end of the inner post the air supply is shut off until the die parts have again been elevated to the position of Figure 5, and until they have been caused to descend into engagement with another blank 32. Then the air and the lubricant may both be turned on before the die operates.

My method of making seamless cans may be briefly summarized as follows:

Circular blanks of sheet metal are first punched out of the sheets and arranged in stacks, and they are fed from the bottom of the stack through an oiling device which coats the top and bottom with oil as they progress toward the die assembly.

The disc-like blanks are fed one by one into the die assembly between the pressure pad and the female die member, and they are first clamped in flat condition against the upper plane surface of the female die by the pressure pad.

The location of the blank at the time is concentric and is determined by a complementary concentric recess on the upper face of the female die member. The blank is subjected to sufficient pressure at its plane portions during the drawing operation to prevent wrinkling.

The next step comprises the drawing of the plane blank into enlarged cylindrical form by means of a composite die body comprising an internal cylindrical post and an external cylindrical sleeve until the plane part of the blank is wholly withdrawn from beneath the pressure pad and shaped into cylindrical form.

The next step comprises the continuance of the drawing operation by moving the inner one, that is the cylindrical inner post of that composite body onward in the same direction, drawing the partially formed can over an annular forming surface into a smaller bore while lubricating the wall of the can on the outside and the inside,,and at the same time applying air pressure to the inside of the can wall during its successive forming operations. lhe oil is, of course, supplied at a higher pressure than the air, which oil pressure determines the amount of lubrication; proper amount of lubrication is determined by trial and error and by inspection of formed cans.

The application of the air pressure causes air to leak along the inside of the can wall, separat- 10 ing it slightly from the forming and supporting die parts on the inside of the can, expanding the can slightly due to the air pressure filling the inside of the can with the fluid air so that it can be drawn moreeasily with less power and less, change of tearing.

The latter forming operation continues until the parts of the partially formed can have been wholly drawn off the outside of the punch sleeve into the smaller bore and shaped to the external cylindrical surface of the inner'post, whereupon a lower forming die member is brought into engagement with the bottom of the can to shape the bottom of the can.

In this 1atter step the bottom of the can is simultaneously formed with a re-enforcing annular ridge and with an annular ridge adjacent the can wall to give it a stable lower supporting surface. When a supporting annular ridge is provided at the outer lower wall of the can, this is more easily made stable and in the same plane than the can is apt to be if its bottom were perfectly plane.

Finally, the formed can is released by the lower die and subjected to internal air pressure while it is on the upper die or internal post to expand the finished can and move it off the end of the post by the thrust developed by air pressure. The can is then guided into a trough which may lead to a conveyor or conductor for cans.

It will thus be observed that I have invented an improved apparatus by means of which seamless cans may be drawn at a single stroke by means of die parts which first form the can into a larger cylindrical shape and then continue to draw it into longer and thinner cylindrical shape, after which the bottom is preferably formed into a definite shape.

By means of my methods and apparatus, suitably controlled, more cans per minute can be made than with any other method and also less labor is employed. Every time a can has to be handled, either manually or by machine, to place it on a new die the cost is increased and this is avoided by means of my apparatus which forms the seamless cans at a single stroke.

I am aware that seamless cans have been previously made by means of a plurality of different operations upon a plurality of different dies in a plurality of steps, but in the devices of the prior art the intermediate products have been permitted to cool before they were acted upon by successive dies or operations. This alternate heating and cooling not only involves separate handling of the intermediate containers by the operators, but such methods harden the metal and require the expenditure of more power in the drawing of the can, this power being dissipated in the act of heating the can a plurality of times, whereas according to my method the blank or container is subjected to a plurality of successive operations immediately following each other while the can metal is still hot, so that the metal does not have a chance to cool and toughen and less power is dissipated in the form of heat.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claim.

Having thus described my invention, what I per clamping surface, a bore, and a counterbore,

with a first annular drawing shoulder at the upper end of said bore, and a second annular drawing shoulder between said bore and counterbore, a sleeve punch in said bore and terminating in a bevelled lower edge, said bore having a complementary bevelled surface above said second drawing shoulder, a pressure pad surrounding said sleeve punch above said clamping surface, a male post slidably mounted in said-sleeve punch to be received in said counterbore, three hydraulic cylinders and pistons, including a first piston connected to actuate said pressure pad, a second piston connected to actuate said sleeve punch,"and a third piston connected to actuate said male post, said male post having a conduit for conducting air under pressure to the lower end of saidpost; and having a second conduit for conducting lubricant under pressure to the interior of said sleeve punch, said second conduit dischargingin: said sleeve punchbelow a plurality of piston rings:

carried by said male post and below the top .of said sleeve punch, said female diehaving a third conduit for lubricant under pressure, discharging above its bevelled surface and second drawing shoulder, said first piston clamping the edges of a circular blank against said female dieto 12 prevent wrinkling. said second and third pistons advancing simultaneously to draw said I blank over said first shoulder to form a large cylindrical container, and said third piston advancing said male post thereafter in said sleeve punch.

to draw said container over said second drawing shoulder, while .said container is lubricated inside and out and subjected to expanding air pressure, the said container passing through said female die and being discharged from the male post by internal air pressure.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date Re.'20,009 Hothersall June 16,- 1936 6043056 Leavitt May '17, 1898 760,921 Rigby May 24,1904 1,431,175 a, Ogden et al; Oct. 10, 1922 1,439,352 Ash etal. Dec. 19,1922 1,486,746 Heisel Mar. 11, 1924 2,289,199 Klockei July'7, 1942 2,292,462 Milford Aug. 11, 1942 2,378,068 Eason June 12,1945 2,545,570 Caldwell Mar. 20, 1951 2,587,076 Verson et a1 Feb. 26, 1952 FOREIGN PATENTS Number Country Date 12,624 Great Britain Sept. 1, 1888

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