US2884886A

US2884886A - Tool for making light metal caps

Info

Publication number: US2884886A
Application number: US439851A
Authority: US
Inventors: Jonsson Josef Einar
Original assignee: Wicanders Korkfabriker AB
Current assignee: Wicanders Korkfabriker AB
Priority date: 1953-06-29
Filing date: 1954-06-28
Publication date: 1959-05-05
Anticipated expiration: 1976-05-05

Description

May 5, 1959 J. E. JONSSON 2,884,886

, TOOL FOR MAKING LIGHT METAL CAPS Filed June 28, 1954 2 Sheets-Sheet 1 //V Vf/V TOR;

Arryk y 1959 E. JONSSON 2,884,886

' TOOL FOR MAKING LIGHT METAL CAPS Filed June 28, 1954 2 Sheets-Sheet 2 T FIG.6

United States Patent 2,884,886 TOOL FOR MAKINGLIGHT METAL'CAPS Josef Eina'r Jonsson, Linkoping, Sweden, assignor to Aktiebolaget'Wicanders Korkfabriker, Eskilstuna, Sweden Application June-28,1954, Serial No. 439,851 Claims priority, application Sweden June 29, 1953 3 Claims. (Cl. 113-42) I The present invention relates to a blanking and forming die' for producing alight metal bottle or similar cap provided with a tearing tab or tongue for tearing oil the cap, the lower edge of the cap being turned back or curled upwardly except for the above-mentioned tab, which remains flat. Otherwise the cap does not differ from a usual cap with a tearing tab and is applied on the bottle in the usual way by pressing the side of the cap against the edge of the bottle. By the folding or curling of its lower edge the cap is attached more securely to the upper edge of the upper annular surface of the groove of the bottle neck. Due to the fact that the tongue or tearing tab remains fiat, the tearing-off of the cap is made possible exactly as in the case of conventional caps. With this novel cap a higher and more lasting sealing pressure is obtained, so that it can resist high pressure in the bottle, such as is generated during the pasteurization of beer and with bottles containing highly carbonated beverages, and in case too much liquid is filled into the bottle.

The cap is produced by a combined blanking and forming tool which cooperates with a supporting ring, and the tool cuts out the blank and forms or draws the cap by a single stroke of the movable parts of the tool, the tool being so arranged that the edge portion of the circular bodyof the cap all round the cap except the tearing tab is turned back by being bent against the curling ring and by being subjected to an evenly distributed pressure, between two surfaces extending from one side of the tongue to the opposite side of the tongue around the central axis of the tool. in a preferred embodiment of the invention a combined punching and forming tool is used, having a sleeve-shaped punch, a die, a stamp in the punch, a curling ring which slidably surrounds a resiliently mounted male forming tool. The resilient mounting of the male forming tool permits it to be moved downwardly independently of the curling ring by the stamp member after the forming of the cap body has been completed and the punch member may then be drawn upwardly independently of the stamp member so that the curling edge of the ring member completes the formation of the curled edge around the previously formed body portion of the cap. The punch member is provided with a laterally extending projection which blanks out the tearing tab portion of the cap. This lateral projection of the punch member and the curling ring have flat cooperating surfaces which grip the tearing tab portion of the cap while the body portion is being formed over the male forming tool member. In this connection, it is a feature of the invention that the stamp and the male forming tool are not only resiliently movable with respect to the punch, but are also movable in the same direction as the punch, after the cap forming motion of the latter has been completed for curling back the lower edge of the cap.

Referring to the accompanying drawing which forms a part of this specification:

Figure l is a perspective view showing a cap produced by the blanking and forming tool.

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Figure 2 is an enlarged'plan view of a blank cut by the tool and from which the cap of Fig. 1 is formed.

Figure 3 is an elevational view, partly in section, showing the blanking and forming tool together with portions of a press in which the tool is mounted.

Figure 4 is an enlarged fragmentary view showing a portion of the lower edge of the cap at an early stage of the curling operation.

Figure 5 is an enlarged fragmentary view similar to Fig. 4 showing a later stage of the curling operation.

Figure 6 is an elevational view similar to Fig. 3 showing the tool after the curling operationvhas been completed.

The finished cap differs from conventional caps of the same type only in its upwardly curled or turned back edge forming the strengthened rim portion 1 (Fig. 1) which enhances the security of closure of a bottle or other container by the cap While freely permitting the cap to be torn off from the container by means of the tab or tongue. The tool, which is mounted in a suitable press, consists of two main parts, one located beneath the strip of blank stock 2 from which the blanks are cut out, the other one being located in its initial position above the strip of blank stock 2. The lower part is mounted in the press table 3. The upper part is mounted in a vertically reciprocating head 3a, which can be moved up and down in a .guideway 4 forming a part of the press frame, otherwise not shown.

The vertical reciprocatory motion of the head 3a is imparted by a connecting rod 5 and an eccentric 6, the latter being mounted on the drive shaft 7 of the press. The connection between the head 3a and the crankshaft comprises a ball and socket joint 8. The above-described press construction is well known, and therefore a more detailed description is not required.

The punching and forming tool consists of the following elements: a sleeve-shaped blanking and drawing punch 10 having a lateral extension 10a, a die 11 cooperating with the punch member 10 for punching the blank shown in Fig. 2, the lateral extension 10a of punch member 10 operating to punch the tearing tab portion of the blank, the die 11 being attached to a sleeve 12 slidably surrounding the punch 10, a stamp 14 movable with-- in the punch, a supporting member 15 fixed in the press table 3, and a supporting and curling ring 16 which is movable up and down in the fixed supporting member 15, and a male forming tool 18 movable up and down through the supporting and curling ring 16. The supporting and curling ring 16 is connected by guide pins 17 to a lower ring 19. The guide pins 17 pass freely slidably through the fixed supporting member 15. The lower ring 19 is yieldingly urged upwardly by a helical compression spring 19a which is held stressed by a nut 19b. The nut 19!) is in threaded engagement with a depending sleeve-shaped extension 13 of the fixed supporting member 15. The punch 10 is fixed in a sleeve 20 which, in turn, is fixed in an annular part 21 of the reciprocating head 3a, that is, between a nut 22 and a shoulder 23. The die 11 and the sleeve 12 are vertically slidable in a well-known manner on the punch 10, as shown for example, in. my US. Patent No. 2,662,498, issued on December 15, 1953, but are disposedat a lower position in which the lower end of the punch 10 is located above the strip of blank stock 2. In this initial position the punch 10 is clear of the strip of stock 2 permitting the strip of stock 2 to be advanced. After advance of the strip of stock 2, the punch 10 will cut a new cap blank as shown in Fig. 2 at the beginning of its next downward stroke. During the downward stroke of punch 10, the die 11 and sleeve 12 are held against downward movement by the fixed supporting member 15 as shown in Figs. 3 and 6. The stamp 14 is movable in the punch 10 and a guide sleeve 24, and is pressed upwardly by a compression spring 25.

As shown in the drawing, the stamp 14 is connected to a vertically reciprocable shaft 27 which, in turn, is connected by a turnbuckle member 28 and a pivot bolt 30a to the free end of an actuating lever 29. The lever 29 is pivoted to the machine frame by a bolt 30 and is provided intermediate its ends with a cam follower roller 32 which cooperates with a cam 34 fixed to the drive shaft 7 for rotation therewith. The cam 34 revolves in a clockwise direction as indicated by the arrow (Fig. 3). Additionally, in accordance with the invention the male forming tool 18 is movable in the fixed supporting member 15, so that it can be depressed against the action of a compression spring 35.

The cap is made in the following way:

The strip of blank stock 2 is fed through the combined tool in a slot 26 between the die 11 and annular sleeve 12. It is fed stepwise by suitable stock feeding mechanism (not shown). After each advance of the strip of blank stock 2, the punch 10 moves through the die 11, whereby a blank is cut out and is carried down toward the supporting ring 16 and the mandrel 18 which both have their upper surfaces at the same level before the start of the forming operation. The punch continues downwards and the forming operation begins, and the stamp 14 comes in contact with the blank. The supporting ring yieldingly moves downwardly and the blank is bent over the male forming tool 18 towards the position shown in Fig. 3. The cap now formed is indicated in the figure by a thick line and is designated by 37. During this forming operation, the tearing tab portion of the cap is gripped between fiat cooperating surfaces of the lateral extension 10a of the punch member and the flat upper surface of the curling ring member as shown in Fig. 3. At this stage, the punch member 10 has not yet reached the lower limit of its travel. At this time, the lever 29 comes into operation. It is rapidly depressed by a projection on the cam 34 with the result that the cap 37 held tight between the stamp 14 and the male forming tool 18, is pressed downwardly with its lower circular edge against the supporting. ring 16 which is stopped by the engagement with the fixed supporting member 15. Fig. 3 shows the first stage of the upward curling of the edge. By the action of a sharp edged oblique surface 40 on the supporting ring 16 the lower circular edge of the cap receives the initial guiding necessary for the curling operation. Figs. 4 and 5 show two later stages of the curling operation. When the punch begins its upward movement, the supporting ring 16 urged upwardly by the spring 19a presses the partially curled edge of the cap against the bevelled internal edge of the punch 10 so that the curling is completed, as shown in Fig. 6. Then the operation is completed and the tool elements resume their initial position, that is, the punch and the stamp return to the starting position above the die 11, so that the strip of stock 2 can be fed one step further in preparation for the next blanking and forming operation of the tool.

During the formation of the curled edge 1, the tearing tab or tongue portion of the cap is not curled since it is held below the laterally projecting portion 10a of the punch 10 which blanks out the tongue portion of the blank.

The invention is not limited to the embodiment shown and described but can be varied within the scope of the invention.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a tool for cutting in a single cycle by successively cooperating die elements blanks of thin sheet material and forming caps from said blanks, each of said caps being provided with a tearing tab extending from the rim thereof, a hollow sleeve-shaped punch provided with a lateral projection the underside of which corresponds to the dimensions of the tab, a die, drive means for projecting said punch through said die to cut a cap blank from said sheet, a stamp mounted for reciprocation within said hollow punch, a second drive means for said stamp, a male member adapted to cooperate with the inner edge of said sleeve-shaped punch for drawing the blank to a cap whose lip is formed with an outwardly curved terminal edge upon a continued actuation of said punch past said die to its full projected position, a resiliently mounted curling ring member slidably surrounding and moved downwardly by the male member and adapted to cooperate with the inner edge of the punch for curling the circumferential curved terminal edge of the cap extending from both sides of the tab upon reverse movement of said sleeve punch drive means, said male member being resiliently movable longitudinally by said stamp in timed relation to said curling ring where by upon retrograde movement of said ring with the stamp and male member in projected position curving of the curved terminal edge of the blank is effected, said punch having its annular internal edge of the underside, as viewed in radial cross-section, convexly rounded substantially along an arc whereby the terminal edge of the cap is formed, and said curling ring member having a flat upper side surrounding the male member and bounded close to it by a slightly erected and, as viewed in radial cross-section, concavely rounded edge provided to cooperate with the rounded terminal edge of the cap whereby said terminal edge is curled, said arc having a radius which is a multiple of the height of the said edge of the curling ring member, and means for controlling simultaneous movement of the stamp and the male member independently of the punch and of the curling ring member.

2. A tool according to claim 1, further comprising guide means adapted to feed said sheet material to said punch in strip stock form.

3. A tool according to claim 1, wherein said means for controlling simultaneous movement comprises a common drive shaft and a plurality of reciprocatory actuating members operated by said shaft and connected separately to said punch and to said stamp.

References Cited in the file of this patent