US3712107A

US3712107A - Apparatus for and method of stripping containers from metal working punches

Info

Publication number: US3712107A
Application number: US00121059A
Authority: US
Inventors: F Duhan
Original assignee: Crown Cork and Seal Co Inc
Current assignee: Crown Cork and Seal Co Inc
Priority date: 1971-03-04
Filing date: 1971-03-04
Publication date: 1973-01-23
Anticipated expiration: 1990-01-23
Also published as: GB1366110A; DE2209599A1; FR2128568A1; IT949842B

Abstract

As a punch is removed from a metal working die during a return stroke, a knock-out member remains extended while the punch is withdrawn from a shell or can body thereby stripping the can body from the punch. The knock-out member is then retracted into the punch. By providing a round trip camming mechanism in combination with a geared knock-out drive mechanism, the knock-out stroke for the knock-out drive is substantially equal to the height of the can and the knock-out member is retracted into the punch before the return stroke is completed.

Description

United States 1 Patent [1 1 Duhan [s41 APPARATUS FoR AND METHOD OF STRIPPING CONTAINERS FROM METAL WORKING PUNCHES [75] Inventor: F. Wm. Duhan, Philadelphia, Pa.

[73] Assignee: Crown Cork & Seal Company, Inc.,

Philadelphia, Pa.

22 Filed: Mareh4, 1971 [21] Appl.No.:121,059'

52 us. Cl 72/345 [51] Int. Cl. ..B2ld 45/00 [58] Field of Search ..72/344, 345, 346, 361, 427

[56} Q 0 References Cited UNITED STATES PATENTS 398,229 2/1889 Chambers ..72/345 3,270,544 9/1966 Maeder et al. .....72/345 3,423,985 1/1969 Stolle ..72/348 3,402,591 9/1968 Maeder ..72/345 Jan. 23, 1973 FOREIGN PATENTS OR APPLICATIONS 703,340 3/1941 Gennany ..72/344 Primary Examiner-Richard J. Herbst Attorney-Woodcock, Washburn Kurtz & Mackiewicz [57] ABSTRACT As a punch is removed from a metal working die during a return stroke, a knock-out member remains extended while the punch is withdrawn from a shell or can body thereby stripping the can body from the punch. The knock-out member is then retracted into the punch. By providing a round trip camming mechanism in combination with a geared knock-out drive mechanism, the knock-out stroke for the knockout drive is substantially equal to the height of the can and the knock-out member is retracted into the punch before the return stroke is completed.

9 Claims, 5 Drawing Figures PATENTEDJAN 23 I973 SHEET 1 UF 3 PATENTED JAN 23 I975 sum 2 or 3 APPARATUS FOR AND METHOD OF STRIPPING CONTAINERS FROM METAL WORKING PUNCIIES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method of and apparatus for drawing, sizing and/or wall ironing container bodies having integral bottom and side wall portions.

In the drawing, sizing and/or wall ironing of such containers, a punch carrying a blank or cup cooperates with a die during a metal working stroke of the punch. By utilizing a plurality of drawing and wall ironing operations, a shell or container body of a type which may be utilized for beer or soft drinks or other products may be formed. Once the metal working stroke is completed, the container must be removed from the punch or the punch from the body.

2. Prior Art Various systems have been proposed and utilized in the prior art to remove the container bodies from the punch after the metal working stroke is completed. These systems have fallen into two categories: punch mounted strippers and die mounted strippers.

Punch mounted stripper systems rely upon the application of pressure on the bottom of the container from the end of the punch. In mechanical stripper systems of this type, a knockout member is extended from the end of the punch to move the container away from the end of the punch. In general, these mechanical stripper systems have been characterized by a rather short knock-out stroke which fails to reliably remove the container from the punch.

In some cases, a pneumatic or hydraulic assist has been proposed. This involves the use of a fluid which is forced through the end of the punch to apply pressure on the container bottom which supplements the pressure provided by the mechanical stripper. Even in these cases, removal of the containers from the punches has not been particularly reliable due to the danger of can collapse or explosion. Furthermore, such systems have been expensive and incapable of meeting high speed container production requirements.

In other cases, ejection has been sought by the means of fluid alone as disclosed in US. Pat. Nos. 3,423,985 Stolle et al. Such a system is also unsatisfactory for the foregoing reasons.

Die mounted stripper systems providing a stripper jaw after the last die have been added to the previously described punch mounted systems to increase reliability. The jaw is designed to prevent a return of the container once the container is past the jaw. Although this is effective as a backup, it is not completely reliable in all instances due to the irregularities of height and the nature of caring incident to wall ironing operations.

SUMMARY OF THE INVENTION It is one object of this invention to provide a method of and apparatus for removing container bodies from metal working punches which is reliable.

It is another object of this invention to provide a method of and apparatus for removing container bodies from metal working punches which is fast.

' In accordance with one important aspect of the invention, the knock-out means is provided with the knock-out stroke equal to a substantial portion of the container body height to reliably remove the container from the punch.

In accordance with another important aspect of the invention, the knock-out means is extended from and retracted into the punch during the return stroke so as to satisfy the high speed production requirements necessary for drawn or ironed can bodies e.g., beverage, aerosol, and others.

In one embodiment of the invention, the ejector system comprises a knock-out means at the end of the punch and extendable therefrom to strip the can from the punch and a knock-out drive means cooperating with the knock-out means for extending the knock-out means from the end of the punch. A round trip camming means cooperates with a cammed means which is coupled to the knock-out drive means so as to extend and then retract the knock-out means with respect to the punch. By providing an appropriate rise and fall portion in the round trip camming means and appropriate gearing in the knock-out drive means, a

knock-out stroke equal to or greater than a substantial portion of the container body height is achieved. In addition, the knockout means may be extended from and retracted into the punch during the return stroke.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional view of a press having a container stripper system embodying the invention with the press shown at the beginning of the metal working stroke for the punch;

FIG. 2 is a simplified sectional view similar to FIG. 1 with the punch shown at the end of the metal working stroke and the beginning of the return stroke;

FIG. 3 is a simplified sectional view similar to FIGS. 1 and 2 with the punch shown during the return stroke;

FIG. 4 is a sectional view of the ejector system taken along section lines 4--4 of FIG. 1; and

FIG. 5 is a sectional view of the ejector system taken along section lines 55 of FIG. 4.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT A press 10 for use in forming containers such as beer or soft drink cans is shown in FIG. 1. The press comprises a metal working punch 12 which is secured to a ram 14 by a chuck l6 and cooperates with at least one metal working die element 48 as shown in FIGS. 2 and 3. In accordance with this invention, a stripper system for removing drawn and/or wall ironed container bodies or shells from the punch 12 is embodied in the press 10.

The stripper system comprises the following components: a knock-out means 18 coaxially and reciprocatingly mounted within the punch 12 which moves through a knock-out stroke to apply pressure to the bottom of the containers to effect stripping thereof; a knock-out drive means 20 mounted on the ram I4 for driving the knock-out means 18 through the knock-out stroke; a cammed means 22 movable parallel to and transversely with respect to the punch 12 and coupled to the knock-out means 20 for actuation thereof; and a round trip camming means 24 which is mounted on a fixed press frame member 26 so as to cam the cammed means 22.

Reference will now be made to FIGS. 1-3 in describing the general operation of the stripper system. As shown in FIG. 1, the punch 12 is in position I at the top or beginning of a metal working stroke with the cammed means 22 located in a first linear portion 28 of a round trip camming path 30. At the beginning of the metal working stroke for the punch 12 and as long as the cammed means 22 remains in the first linear portion 28, a drive mechanism of the knock-out drive means is stationary. In particular, a rack 32, a small gear 34 engaged by the rack 32, and a large gear 36 coupled to a small gear 34 through a shaft 38 remain stationary.

As a consequence, a rack portion 40 of the knockout means 18 remains stationary with respect to the gear 36 thereby maintaining a knock-out pad 42 and a connecting knock-out rod 44 retracted within the punch 12. The knock-out drive means 20 and the knock-out means 18 remain in this condition as the cammed means 22 enters and passes through a second linear portion 46 of the round trip camming path 30. When the cammed means 22 reaches the bottom of the second linear portion 46, as shown in positions II and Ill in FIG. 2, the metal working stroke of the punch 12 is completed. In position III, the container C has passed substantially through the die element 48.

The return stroke of the punch 12 now begins simultaneously with the knock-out stroke of the knock-out means 18. During the initial portion of the punch return stroke, the cammed means 22 moves through a rise portion 50 of the round trip camming path 30 which communicates with the bottom of the second linear portion 46. As the cammed means 22 moves away from the second linear path 46, the rack 32 which is coupled to the cammed means 22 also moves thereby rotating the

gears

34 and 36 in a clockwise motion and forcing the rack gear portion 40 of the knock-out drive means down. By providing the appropriate rate of rise for the rise portion 50 and an appropriate gear ratio for the

gears

34 and 36, the knock-out pad 42 may remain substantially stationary with respect to the die 48 as the punch 12 is removed from the die 48. In this manner, the knock-out pad 42 is extended toward the bottom of the punch 12 to an ultimate position shown in FIG. 3 corresponding to position IV of the cammed means 22.

In accordance with one very important aspect of the invention, the knock-out pad 42 and the rod 44 are extended a distance substantially equal to the height of the container C. This assures complete separation of the container C from the punch 12 thereby providing reliable removal of the container C from the punch.

With the knock-out stroke now completed, the cammed means 22 enters a fall portion 52 of the round trip camming path 30 as the return stroke of the punch 12 continues. At this time, the cammed means 22 moves up and to the right toward the first and second

linear portions

28 and 46 along with the rack 32 coupled thereto. This produces a counterclockwise rotation of the

gears

34 and 36 resulting in the upward movement of the rack gear portion 40 and the knockout pad 42. By the time the cammed means 42 has reached position V, and the juncture of

portions

28 and 46, the return stroke of the knock-out pad 42 has been completed and the knock-out pad and the knock-out rod 44 have been entirely retracted within the punch 12.

In accordance with another very important aspect of the invention, the knock-out means travels at a rather rapid rate to assure complete retraction of the knockout pad 42 before the return stroke of the punch 12 is completed. This is provided by a rather steep incline in the fall portion 52 in combination with the gear ratio between the

gears

34 and 36. Once the knock-out pad 42 and the rod 44 have been completely retracted within the punch 12, the cammed means 22 moves from position V through position VI and to position I as the return stroke is completed. Throughout this time, the rack 32, the

gears

34 and 36, and the worming gear 40 remain stationary with respect to one another.

Detailed aspects of the stripper system will now be described with reference to FIGS. 4 and 5. It will be understood that the cammed means 22 moves from position II to position III without any movement of the rack 32. Similarly, the cammed means 22 moves from position V to position VI without any transverse movement of the rack 32. This is achieved by the spring biased coupling 54 between the cammed means 22 which comprises a head 56 of a bolt 58 mounted in a sliding block 60 and the rack 32 having an axial bore 62 as best shown in FIG. 4. The spring biased coupling 54 comprises a rod 64 which is threadedly fastened to the sliding block 60 and extends into the axial bore 62 with a helical spring 65 located between the other end 66 of the rod 64 and one end 68 of the rack 32.

By providing a spring biased coupling with the spring 64 in a state of compression with the cammed means 22 located in position II, the cammed means 22 is in effect pulled to position III without movement of the rack 32. The knock-out pad 42 which engages a complementary conical surface 70 at the bottom of the punch 12 requires the block 60 to move rather than the rack 32. Similarly, relative movement of the worm gear 40, gears 34 and 36, and the rack 32 is precluded so as to compress the spring 65 as the cammed means 22 reaches position VI and returns to position I. In this manner, the cammed means 22 is spring loaded at the beginning of each metal working stroke.

As also shown in FIGS. 4 and 5, the

gears

34 and 36 comprise a unitary member 72 rotatably mounted on a pin 74 which extends through

opposite wall members

75 and 76 of the knock-out drive means 20 with a nut 78 engaging a threaded portion 80 at the wall portion 74. As mentioned previously, the gear ratio between the

gears

34 and 36 is properly chosen in view of the rise and fall of the round trip camming path 30 to maintain the knock-out pad 30 substantially stationary with respect to the die 48 at the beginning of the return stroke for the punch 12 and subsequently moving the knock-out pad 42 at twice the speed of the punch 12. Utilizing the camming contour comprising the rise portion 50 and the fall portion 52, a gear ratio of 2:1 for the

gears

36 and 34 has been found particularly suitable.

Referring to FIG. 1, a spring biased lever 82 is shown at the juncture of the first linear portion 28, the second linear portion 46 and the fall portion 52. The lever 82 including an arm 84 is maintained in a position shown in full during the metal working stroke of the punch 12 by a spring 86 fastened to the block 88 of the camming means 24 by a screw 90. This position is maintained during the metal working stroke when the cammed means 22 moves from the first linear portion 28 to the second linear portion 46. The position shown in phantom results when the cammed means 22 moves from the fall portion 52 to the first linear portion 58 after completion of the knock-out stroke and during the end of the return stroke for the punch 12.

For purposes of simplification, a fragmentary portion of the press including bearings 92 and bearing surfaces 94 associated with the ram 14 are shown. It will be appreciated that various types of container forming equipment well known in the art may embody the stripper system of this invention. It will also be appreciated that the die element 48 is merely representative of the die or plurality of dies which might be utilized in connection with the ejector system. Similarly, the punch 12 is also representative. The stripper system may be utilized in a punch and die combination such as that shown in copending application Ser. No. 62,791, filed Aug. 11, 1970, which is incorporated herein by reference. As shown in this application, the dies perform various drawing, sizing and wall ironing operations. Such a punch and die combination will produce the containers disclosed in copending application Ser. No. 57,124, filed July 22, 1970, which is also incorporated herein by reference.

While preferred forms and arrangements have been shown to illustrate the invention, it will be understood that various changes may be made without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. In an apparatus for drawing, sizing and/or wall ironing cans having at least one die and a punch for carrying a blank or cup into metal working engagement with said die and wherein said punch enters said die during a metal working stroke and is removed from said die during a return stroke, said apparatus comprising a can stripper system for removing said can from said punch comprising:

a knock-out means at the end of said punch and extendable therefrom to eject the can from said punch;

a knock-out drive means cooperating with said knock-out means for extending said knock-out means, from the end of said punch;

a cammed means coupled to said knock-out drive means and said punch and movable with said punch in a direction parallel with the movement of said punch during the metal working stroke and the return stroke; and round trip camming means for camming said cammed means in a direction transverse to the movement of said punch during the metal working stroke and the return stroke so as to actuate said knock-out drive means to extend and then retract said knock'out means with respect to said punch.

2. The apparatus of claim 1 wherein said round trip camming means comprises a rise portion and a fall portion, said camming means moving along said rise portion and then said fall portion during the return stroke of said punch so as to extend said knock-out means and then retract said knock-out means during the return stroke.

3. The apparatus of claim 2 wherein said knock-out drive means includes gear means, the combination of said rise portion of said camming means with said gear means rendering said knock-out means substantially stationary with respect to said die as said cammed means is cammed by said rise portion during the return stroke thereby extending said knock-out means from said punch and moving said knock-out means at a more rapid rate with respect to said die than said punch moves with respect to said die as said cammed means is cammed by said fall portion during the return stroke thereby retracting said knock-out means into said punch.

4. The apparatus of claim 2 wherein said knock-out drive means includes gear means, the combination of said rise portion and said fall portion of said camming means with said gear means producing a knock-out stroke having a length equal to a substantial portion of the can height.

5. The apparatus of claim 2 wherein said knock-out means comprises a rack portion; and said knock-out drive means comprises a rack coupled to said camming means and a gear means coupling said rack portion to said rack, said rack extending transversely with respect to said knock-out means and said punch, movement of said rack resulting in movement of said knock-out means.

6. The method of claim 5 wherein said gear means is characterized by a ratio of 2:1 whereby said knock-out means moves at twice the speed of said rack.

7. The apparatus of claim 6 wherein said knock-out drive means includes a spring means coupling said cammed means to said rack means, said spring means biasing said cammed means so as to force said cammed means to enter said rise portion of said camming means at the end of the metal working stroke.

8. The apparatus of claim 7 wherein said round trip camming means includes a first linear portion receiving said cammed means during the early portion of said metal working stroke and the latter portion of said return stroke and a second linear portion receiving said cammed means during the latter portion of said metal working stroke, said rise portion communicating with said second linear portion and said fall portion communicating with said first linear portion and said second linear portion at the juncture therebetween.

9. The apparatus of claim 8 including a spring biased lever at said juncture, said lever being spring biased to force said cammed means to move from said first linear portion to said second linear portion during the metal working stroke of said punch while permitting said cammed means to move from said fall portion to said first linear portion during the return stroke of said punch.

i i i i t

Claims

1. In an apparatus for drawing, sizing and/or wall ironing cans having at least one die and a punch for carrying a blank or cup into metal working engagement with said die and wherein said punch enters said die during a metal working stroke and is removed from said die during a returN stroke, said apparatus comprising a can stripper system for removing said can from said punch comprising: a knock-out means at the end of said punch and extendable therefrom to eject the can from said punch; a knock-out drive means cooperating with said knock-out means for extending said knock-out means, from the end of said punch; a cammed means coupled to said knock-out drive means and said punch and movable with said punch in a direction parallel with the movement of said punch during the metal working stroke and the return stroke; and a round trip camming means for camming said cammed means in a direction transverse to the movement of said punch during the metal working stroke and the return stroke so as to actuate said knock-out drive means to extend and then retract said knock-out means with respect to said punch.