Metal deforming – With cutting – By shearing tool-couple
Reexamination Certificate
2002-06-12
2003-12-09
Larson, Lowell A. (Department: 3725)
Metal deforming
With cutting
By shearing tool-couple
C072S348000
Reexamination Certificate
active
06658911
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The invention relates to a method and apparatus for forming end shells for metal containers, and particularly to forming the end shell with an annular reinforcing rib and a peripheral curl. Even more particularly, the invention relates to forming the reinforcing rib and peripheral curl on the end shell in a single press cycle in which the end shell is formed from a starting blank of sheet material.
2. Background Information
In the metal container art, containers usually consist of a body formed of lightweight metals such as an aluminum, and a separate end shell for closing the container, also formed of lightweight metal from strip material. It is desirable in forming the end shells to form a peripheral curl to enable the end shells to be stacked and transported between work stations without the end shells nesting too tightly together and sticking, hampering their movement through various production stages until they are ultimately seamed onto the finished container. This peripheral curl may also facilitates the seaming of the end shell on the open top of the container.
Various types of tooling has been developed for forming this peripheral curl, most of which requires a separate machine and tooling station separate from that of the press in which the end shell is formed. One common tooling uses curling rolls such as shown in U.S. Pat. No. 4,116,361. However, these prior art curl forming machines involve transporting the end shells from the forming press to a second station for the curling operation which requires additional equipment for handling the end shells.
Other types of tooling have attempted to form the peripheral curl on the end shell in the same press or tooling station in which the end shell is formed to avoid this transfer problem and expense. Examples of such single station tooling for forming the end shell and peripheral curl are shown in U.S. Pat. Nos. 4,031,836, 4,372,720, 4,574,608, and 6,290,447. In this type of tooling, the initial disc blank and final end shell having the peripheral curl thereon is formed and ejected from the press at the same level in the press. It has been found that production speed can be increased by performing several of the forming operations, such as blanking of the initial disc blank and forming a preliminary cup-shaped blank at a first level, and then final forming the end shell at a second level, at which level the shell is then ejected from the press. Examples of such multi-level end shell production type presses are shown in U.S. Pat. Nos. 4,903,521 and 4,977,772. However, none of these multilevel presses form a peripheral curl on the end shell.
It is also desirable to form an annular reinforcing rib in the end shell to provide strength and rigidity thereto. Various types of tooling have been developed for forming an annular reinforcing rib in the end shell between the central panel and peripheral edge. However, certain types of tooling use a die having a male portion which engages and forces the metal into an opposed complementary female die providing a positive engagement between the tooling and metal. This die contact can cause thinning and wrinkling of the metal due to the pressure exerted by the dies against the metal trapped therebetween. Examples of such tooling are shown in U.S. Pat. Nos. 4,516,420, 4,587,825, 4,713,958, 4,715,208, 4,716,755, 4,808,052, and 4,977,772. Another type of tooling pushing the metal into an enlarged cavity without a male or positive female die component, such as shown in U.S. Pat. Nos. 4,109,599 and 4,571,978. Since the cavity is enlarged, it does not form a true radius for the reinforcing rib, which can reduce to strength of the resulting rib.
Thus, the need exists for an apparatus and method for forming container end shells with an annular reinforcing rib and a peripheral curl in a single press cycle wherein the blanking and partial forming of the end shell is carried out at a first level and the formation of the final end shell, reinforcing rib and peripheral curling is carried out prior to ejection of the end shell from the press at the second level in order to increase the speed of production.
BRIEF SUMMARY OF THE INVENTION
The present invention provides an apparatus and method for forming an end shell for use on a container body which is formed in a single press cycle at a single work station wherein a portion of the end shell is produced at a first level and the final forming of the end shell, including forming an annular reinforcing rib and peripheral curl, is formed at a second level in the press, from which level the finished end shell is ejected.
Another aspect of the present invention provides for the forming of the end shell without complicated and expensive modifications for retrofitting existing presses and which eliminates the need for expensive and complicated transfer mechanisms for transferring the end shell to an adjacent curling station.
A further aspect of the invention preferably provides an apparatus and method for forming a plurality of the end shells in a single cycle of the press wherein the reinforcing rib and peripheral curl are formed on the end shell during the upward movement of an inner ram, and in which a curl forming outer die ring also functions as the lift ring for moving the completed end shell back to the second level for subsequent ejection from the press.
Still another feature of the invention is to form the annular reinforcing rib in the end panel of the shell just prior to forming the end curl during upward movement of an outer die core ring and aligned outer punch shell.
Another feature of the invention is forming the peripheral curl by increasing the overall outer diameter of the end shell in contrast to the heretofore methods and apparatus which reduce the diameter of the end shell to form the peripheral curl.
A further feature of the invention is to provide an apparatus and method for forming an end shell having an annular reinforcing rib and a peripheral curl which avoids any thinning of the metal and which prevents wrinkling of the metal by maintaining a portion of the frustro-conical chuckwall portion of the end shell in a secure clamped position between an inner pressure member and an inner die core ring during formation of the reinforcing rib and peripheral curl.
The present invention forms the peripheral curl by pivotally moving an outer portion of an elongated chuckwall of an end shell blank during reverse movement of an outer die core ring and outer punch sleeve by providing a slip-fit clamping engagement of the outer periphery of the chuckwall therebetween.
The present invention also forms an annular reinforcing rib in the end shell by pushing metal from the chuckwall into an annular groove or female die component formed in the punch core during reverse movement of an outer die core ring and outer punch sleeve wherein the groove matching the desired radius of the reinforcing rib and functions as the female die component, but without a male die component engaging the metal.
The foregoing advantages, construction, and operation of the present invention will become more readily apparent from the following description and accompanying drawings.
REFERENCES:
patent: 3844145 (1974-10-01), Bozek
patent: 4031836 (1977-06-01), Grise et al.
patent: 4116361 (1978-09-01), Stargell
patent: 4372720 (1983-02-01), Herdzina et al.
patent: 4516420 (1985-05-01), Bulso, Jr. et al.
patent: 4571978 (1986-02-01), Taube et al.
patent: 4574608 (1986-03-01), Bulso, Jr. et al.
patent: 4587825 (1986-05-01), Bulso, Jr. et al.
patent: 4713958 (1987-12-01), Bulso, Jr. et al.
patent: 4715208 (1987-12-01), Bulso, Jr. et al.
patent: 4716755 (1988-01-01), Bulso, Jr. et al.
patent: 4808052 (1989-02-01), Bulso, Jr. et al.
patent: 4977772 (1990-12-01), Bulso, Jr. et al.
patent: 6290447 (2001-09-01), Siemonsen et al.
Larson Lowell A.
Sand & Sebolt
Sequa Can Machinery, Inc.
LandOfFree
Method and apparatus for forming container end shells does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for forming container end shells, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for forming container end shells will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3133809