METHOD AND APPARATUS FOR FORMING A CAN END
United States Patent 3844154
A method and apparatus for forming a can end closure in a press having means for forming the closure in a single stroke of the press. The means incudes a die assembly for forming an end panel having a formed flange terminating in a partial curl which is formed on closing stroke of the press and then completing the curl on the opening stroke of the press.
US Patent References:
Apparatus for forming sheet metal caps
Jeneson - October 1932 - 1884708
Lid-making apparatus
Lawson - September 1956 - 2763228
Disposable pan
Hennies - October 1961 - 3004685
Die pads for ram type presses
Williamson - September 1964 - 3147722
Die assembly
Buhrke - December 1964 - 3163142
Apparatus for forming sheet metal caps
Jeneson - October 1932 - 1884708
Lid-making apparatus
Lawson - September 1956 - 2763228
Disposable pan
Hennies - October 1961 - 3004685
Die pads for ram type presses
Williamson - September 1964 - 3147722
Die assembly
Buhrke - December 1964 - 3163142
Application Number:
05/308217
Publication Date:
10/29/1974
Filing Date:
11/20/1972
View Patent Images:
Export Citation:
Assignee:
Continental Can Company, Inc. (New York, NY)
Primary Class:
Other Classes:
72/350, 72/348, 72/351, 413/8
International Classes:
B21D37/08; B21D51/44; B21D37/00; B21D51/38; B21D28/00
Field of Search:
113/1F,121R,121C 72/348,350,351,334
US Patent References:
Primary Examiner:
Lanham C. W.
Assistant Examiner:
Duzan, James R.
Attorney, Agent or Firm:
Kowalik, John Kerwin Joseph Dittmann William J. E. A.
Parent Case Data:
This is a continuation-in-part of application Ser. No. 56,423 filed July 20, 1970 and now abandoned.
Claims:
What is claimed is
1. Apparatus for forming a container end closure having a curled flange adapted to be double seamed to a container body, said apparatus comprising an upper die assembly and a lower die assembly mounted for reciprocable movement between an open and closed position, said upper die assembly having an axial punch, said lower die assembly having an axial anvil, an annular punch on said upper die assembly and a coacting cutting ring on said second die assembly for severing a disk blank from a sheet metal strip, said punch and anvil having complementary center opposing profiles including means for grasping and forming a center portion of the blank therebetween during the closing portion operation of said means, an upper drawing ring disposed between said annular punch and said axial punch, and a lower drawing ring disposed between said cutting ring and said anvil, groove means on said cutting ring coacting with said lower drawing ring for forming a peripheral flange on said disk blank when said die assemblies move to said closed position, said upper drawing ring having a circumferential groove including an inwardly contoured surface at the upper end thereof for curling said flange inwardly when said die assemblies move to said open position to form a curl about the periphery of said disk accompanied by simultaneous separating movement of said means to an open position and releasing said center portion whereby during curling said blank is grasped solely about its periphery by said lower drawing ring and said axial punch.
2. The invention as defined in claim 1 wherein said first and second drawing rings are spring biased toward each other.
3. The invention as defined in claim 1 wherein said groove in said lower cutting ring opens upwardly, and wherein said lower drawing ring includes a convex depression and said axial punch includes a surface complementary to said concave depression for forming a radius connecting the peripheral flange to the remainder of said disk.
4. The method of forming an end closure which comprises severing a blank from a strip of sheet metal between a pair of die assemblies, clamping the center portion of said blank by die members and clamping the peripheral portion of the blank by a die element and one of said die members of said assemblies and forming a semi-curled peripheral flange on said blank between said one of the die members and element as they move to a closed position, and releasing said center portion from between the die members and while holding said blank between said one die member and element only at said peripheral portion turning the edge of the semi-curled flange by engaging another die element therewith to form an inwardly directed curl as said die assemblies move to an open position.
1. Apparatus for forming a container end closure having a curled flange adapted to be double seamed to a container body, said apparatus comprising an upper die assembly and a lower die assembly mounted for reciprocable movement between an open and closed position, said upper die assembly having an axial punch, said lower die assembly having an axial anvil, an annular punch on said upper die assembly and a coacting cutting ring on said second die assembly for severing a disk blank from a sheet metal strip, said punch and anvil having complementary center opposing profiles including means for grasping and forming a center portion of the blank therebetween during the closing portion operation of said means, an upper drawing ring disposed between said annular punch and said axial punch, and a lower drawing ring disposed between said cutting ring and said anvil, groove means on said cutting ring coacting with said lower drawing ring for forming a peripheral flange on said disk blank when said die assemblies move to said closed position, said upper drawing ring having a circumferential groove including an inwardly contoured surface at the upper end thereof for curling said flange inwardly when said die assemblies move to said open position to form a curl about the periphery of said disk accompanied by simultaneous separating movement of said means to an open position and releasing said center portion whereby during curling said blank is grasped solely about its periphery by said lower drawing ring and said axial punch.
2. The invention as defined in claim 1 wherein said first and second drawing rings are spring biased toward each other.
3. The invention as defined in claim 1 wherein said groove in said lower cutting ring opens upwardly, and wherein said lower drawing ring includes a convex depression and said axial punch includes a surface complementary to said concave depression for forming a radius connecting the peripheral flange to the remainder of said disk.
4. The method of forming an end closure which comprises severing a blank from a strip of sheet metal between a pair of die assemblies, clamping the center portion of said blank by die members and clamping the peripheral portion of the blank by a die element and one of said die members of said assemblies and forming a semi-curled peripheral flange on said blank between said one of the die members and element as they move to a closed position, and releasing said center portion from between the die members and while holding said blank between said one die member and element only at said peripheral portion turning the edge of the semi-curled flange by engaging another die element therewith to form an inwardly directed curl as said die assemblies move to an open position.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to containers and more particularly to a new and improved apparatus and method for forming a container end closure.
2. The Prior Art
Currently can end closures are made in two or more forming operations. Initially a blank is cut from a strip of sheet material and the blank is then formed or drawn into a panel having a turned projecting flange about the periphery to form a partial curl. Thereafter, the blank with the partially formed curl is transferred to another press wherein the curl is completed.
While this prior apparatus is satisfactory, the two operations are time consuming and also require additional tooling so that the overall cost of the end is increased.
SUMMARY OF THE INVENTION
By the present invention, it is proposed to provide a new and improved method and apparatus for forming a can end closure which overcomes the deficiencies encountered heretofore.
This is accomplished generally by the provision of an apparatus which is capable of forming a complete end in a single die assembly. The die assembly comprises an upper die sub-assembly and lower die sub-assembly adapted to be mounted in a press. The upper and lower die sub-assembly include means for forming the profile of the container end closure on the down stroke or closing stroke of the die assembly and also a peripheral flange defining a partial curl. Means are operative during the opening or upward stroke of the die sub-assemblies to complete the curl.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary sectional view taken in elevation illustrating a symmetrical one-half of an end forming apparatus embodying the structure of the present invention and showing the die assembly in the open position;
FIG. 2 is a fragmentary view, similar to FIG. 1 but showing the die assemblies in a partially closed position immediately prior to the blanking operation;
FIG. 3 is a view, similar to FIG. 2 of the apparatus but showing the sub-assemblies in the fully closed position;
FIG. 4 is a fragmentary enlarged view of the die assembly components for forming the partially curled flange on the end closure;
FIG. 5 is a fragmentary view, similar to FIG. 3, but showing the die sub-assemblies during the return to the open position; and
FIG. 6 is an enlarged fragmentary view showing the die sub-assemblies in the open position and the end closure with the curl completely formed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 through 6, there is shown a die assembly 10 comprising generally an upper die sub-assembly 12 and lower die sub-assembly 14. The sub-assemblies are mounted on the head and bed respectively of a press 15 so as to be reciprocable between an open position and a closed position.
The various die elements or tools on the upper die sub-assembly 12 are arranged in concentric relationship and include an outer annular punch 18, a spring biased retractable upper or first annular drawing ring 20 and a fixed axial die punch 22.
Compression springs 23 are angularly spaced about the axial die punch 22 and are disposed between the upper face of drawing ring 20 and the underside of an upper die plate 13. The compression springs 23 normally bias the drawing ring 20 into engagement with the sheet material S from which the end is formed as shown in FIG. 2.
The punch 18 is provided with a shoulder 19 which is engageable with a complementary shoulder 21 on the drawing ring 20.
A shearing edge 25 is provided along the lower edge of the punch 18 for shearing a circular blank from the sheet material S during the blanking operation.
The upper drawing ring 20 is axially slidable relative to the fixed axial die punch 22 and is formed with an annular end wall 26. End wall 26 is disposed in co-planar relationship with end wall 24 at the initial and final stages of the end forming operation as shown in FIG. 1 and in FIG. 6. A groove 27 terminating in a concave section 27a is formed along the inner circumference of the annular end wall 26. The concave section 27a forms a curl about the periphery of the end closure, as more fully to be described hereinafter.
As shown in FIG. 6, the bottom face of the axial die punch 22 is formed with a convex annular end wall 28 and concentric depressions 29 and 30.
The die elements on the lower die sub-assembly 14 are also arranged in concentric relationship and are coaxially aligned with their counterparts on the upper die sub-assembly 12 for coaction therewith during closing and opening of the die assembly 10. The lower die sub-assembly 14 includes a lower support ring 40, a cutting ring 41, a lower or second drawing ring 42 and an axial anvil 43.
The cutting ring 41 and the anvil 43 are both fixedly attached to the upperface of a lower die block 16 while the lower support ring 40 and the drawing ring 42 are mounted for reciprocal movement relative thereto.
Support rods 44 supporting the support element 40 are slidably disposed in openings extending through the cutting ring 41 and the lower die block 16. Compression springs 46 located in the opening between the support rods 44 and the bed of the press (now shown) normally bias the latter and thereby the lower support element 40 upwardly. Upward movement of the rods 44 is limited by heads 47 which engage the underside 39 of the cutting ring 41.
Ring 42 is formed with a shoulder 48 which engages a complementary shoulder 49 on the axial anvil 43. During the operation of the apparatus, ledge 48 is engaged by the shoulder 49 to limit the upward movement of the drawing ring 42 with respect to the axial die member 43. Biasing the drawing ring shoulder 48 into engagement with the shoulder 49 is a rod 49a which is biased upwardly by a compression spring 49b.
As shown in FIG. 2, the lower support member 40 is dimensioned to accomodate the cutting ring 41 and is formed with an upper end wall 50 for supporting the sheet material S. The cutting ring 41 is dimensioned to slidably accommodate the drawing ring 42 which is formed with an annular end wall 51 having a sharp edge 53 at its outermost edge for shearing the sheet material 16. End wall 51 is disposed in co-planar relationship with the end wall 50 at the beginning of the forming operation as shown in FIG. 1 and after the final state of the forming operation as shown in FIG. 1. The cutting ring 41 is also formed with a groove 52 along the inner circumference adjacent the end wall 51.
Groove 52 is shaped to provide a profile including a semi-curl 60 in the form of an upwardly projecting flange about the periphery of the shell 16. The profile of the groove 52 may be varied to compensate for the spring back characteristic of the sheet material used. The drawing ring 42 embraces the axial die member 43 and is formed with an annular end wall having a concave depression 54. The concave depression 54 provides support for the outer surfaces of the end closure flange subsequently to be formed and forms a radius 62 which merges with the chuck wall 63 of the end closure.
As the die sub-assemblies 12, 14 are closed and brought together, the various die elements coact to form the container end closure as hereinafter to be described. Initially, the shear cutting edges 25, 53 of the punch 18 and the cutting ring 41, respectively, coact to sever a blank B from the sheet material 16. At the same time, the axial die punch 22 engages the blank B to press it against the axial anvil 43 as shown in FIG. 3.
The cutting ring 41 also coacts with axial die punch 22 so that the convex surface 28 and complementary concave surface 54 form the radius 62 and the groove 52 forms the upstanding flange 61 about the periphery. In this manner the partial curl 60 is formed.
When the die sub-assemblies 12 and 14 are moved to the open position, the ring 42 is biased upwardly as shown in FIG. 6 causing the lid or enclosure 16 to be separated from the anvil 43. At the same time the ring 42 also forces the upstanding flange 61 into the grooves 27 and 27a so that the flange 61 is turned inwardly about an arc. In this matter a completed curl 65 is formed about the periphery of the end so that the latter may be double seamed to a container in the usual manner.
1. Field of the Invention
The present invention relates to containers and more particularly to a new and improved apparatus and method for forming a container end closure.
2. The Prior Art
Currently can end closures are made in two or more forming operations. Initially a blank is cut from a strip of sheet material and the blank is then formed or drawn into a panel having a turned projecting flange about the periphery to form a partial curl. Thereafter, the blank with the partially formed curl is transferred to another press wherein the curl is completed.
While this prior apparatus is satisfactory, the two operations are time consuming and also require additional tooling so that the overall cost of the end is increased.
SUMMARY OF THE INVENTION
By the present invention, it is proposed to provide a new and improved method and apparatus for forming a can end closure which overcomes the deficiencies encountered heretofore.
This is accomplished generally by the provision of an apparatus which is capable of forming a complete end in a single die assembly. The die assembly comprises an upper die sub-assembly and lower die sub-assembly adapted to be mounted in a press. The upper and lower die sub-assembly include means for forming the profile of the container end closure on the down stroke or closing stroke of the die assembly and also a peripheral flange defining a partial curl. Means are operative during the opening or upward stroke of the die sub-assemblies to complete the curl.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary sectional view taken in elevation illustrating a symmetrical one-half of an end forming apparatus embodying the structure of the present invention and showing the die assembly in the open position;
FIG. 2 is a fragmentary view, similar to FIG. 1 but showing the die assemblies in a partially closed position immediately prior to the blanking operation;
FIG. 3 is a view, similar to FIG. 2 of the apparatus but showing the sub-assemblies in the fully closed position;
FIG. 4 is a fragmentary enlarged view of the die assembly components for forming the partially curled flange on the end closure;
FIG. 5 is a fragmentary view, similar to FIG. 3, but showing the die sub-assemblies during the return to the open position; and
FIG. 6 is an enlarged fragmentary view showing the die sub-assemblies in the open position and the end closure with the curl completely formed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 through 6, there is shown a die assembly 10 comprising generally an upper die sub-assembly 12 and lower die sub-assembly 14. The sub-assemblies are mounted on the head and bed respectively of a press 15 so as to be reciprocable between an open position and a closed position.
The various die elements or tools on the upper die sub-assembly 12 are arranged in concentric relationship and include an outer annular punch 18, a spring biased retractable upper or first annular drawing ring 20 and a fixed axial die punch 22.
Compression springs 23 are angularly spaced about the axial die punch 22 and are disposed between the upper face of drawing ring 20 and the underside of an upper die plate 13. The compression springs 23 normally bias the drawing ring 20 into engagement with the sheet material S from which the end is formed as shown in FIG. 2.
The punch 18 is provided with a shoulder 19 which is engageable with a complementary shoulder 21 on the drawing ring 20.
A shearing edge 25 is provided along the lower edge of the punch 18 for shearing a circular blank from the sheet material S during the blanking operation.
The upper drawing ring 20 is axially slidable relative to the fixed axial die punch 22 and is formed with an annular end wall 26. End wall 26 is disposed in co-planar relationship with end wall 24 at the initial and final stages of the end forming operation as shown in FIG. 1 and in FIG. 6. A groove 27 terminating in a concave section 27a is formed along the inner circumference of the annular end wall 26. The concave section 27a forms a curl about the periphery of the end closure, as more fully to be described hereinafter.
As shown in FIG. 6, the bottom face of the axial die punch 22 is formed with a convex annular end wall 28 and concentric depressions 29 and 30.
The die elements on the lower die sub-assembly 14 are also arranged in concentric relationship and are coaxially aligned with their counterparts on the upper die sub-assembly 12 for coaction therewith during closing and opening of the die assembly 10. The lower die sub-assembly 14 includes a lower support ring 40, a cutting ring 41, a lower or second drawing ring 42 and an axial anvil 43.
The cutting ring 41 and the anvil 43 are both fixedly attached to the upperface of a lower die block 16 while the lower support ring 40 and the drawing ring 42 are mounted for reciprocal movement relative thereto.
Support rods 44 supporting the support element 40 are slidably disposed in openings extending through the cutting ring 41 and the lower die block 16. Compression springs 46 located in the opening between the support rods 44 and the bed of the press (now shown) normally bias the latter and thereby the lower support element 40 upwardly. Upward movement of the rods 44 is limited by heads 47 which engage the underside 39 of the cutting ring 41.
Ring 42 is formed with a shoulder 48 which engages a complementary shoulder 49 on the axial anvil 43. During the operation of the apparatus, ledge 48 is engaged by the shoulder 49 to limit the upward movement of the drawing ring 42 with respect to the axial die member 43. Biasing the drawing ring shoulder 48 into engagement with the shoulder 49 is a rod 49a which is biased upwardly by a compression spring 49b.
As shown in FIG. 2, the lower support member 40 is dimensioned to accomodate the cutting ring 41 and is formed with an upper end wall 50 for supporting the sheet material S. The cutting ring 41 is dimensioned to slidably accommodate the drawing ring 42 which is formed with an annular end wall 51 having a sharp edge 53 at its outermost edge for shearing the sheet material 16. End wall 51 is disposed in co-planar relationship with the end wall 50 at the beginning of the forming operation as shown in FIG. 1 and after the final state of the forming operation as shown in FIG. 1. The cutting ring 41 is also formed with a groove 52 along the inner circumference adjacent the end wall 51.
Groove 52 is shaped to provide a profile including a semi-curl 60 in the form of an upwardly projecting flange about the periphery of the shell 16. The profile of the groove 52 may be varied to compensate for the spring back characteristic of the sheet material used. The drawing ring 42 embraces the axial die member 43 and is formed with an annular end wall having a concave depression 54. The concave depression 54 provides support for the outer surfaces of the end closure flange subsequently to be formed and forms a radius 62 which merges with the chuck wall 63 of the end closure.
As the die sub-assemblies 12, 14 are closed and brought together, the various die elements coact to form the container end closure as hereinafter to be described. Initially, the shear cutting edges 25, 53 of the punch 18 and the cutting ring 41, respectively, coact to sever a blank B from the sheet material 16. At the same time, the axial die punch 22 engages the blank B to press it against the axial anvil 43 as shown in FIG. 3.
The cutting ring 41 also coacts with axial die punch 22 so that the convex surface 28 and complementary concave surface 54 form the radius 62 and the groove 52 forms the upstanding flange 61 about the periphery. In this manner the partial curl 60 is formed.
When the die sub-assemblies 12 and 14 are moved to the open position, the ring 42 is biased upwardly as shown in FIG. 6 causing the lid or enclosure 16 to be separated from the anvil 43. At the same time the ring 42 also forces the upstanding flange 61 into the grooves 27 and 27a so that the flange 61 is turned inwardly about an arc. In this matter a completed curl 65 is formed about the periphery of the end so that the latter may be double seamed to a container in the usual manner.