Metal deforming – By application of fluent medium – or energy field – With cutting
Reexamination Certificate
2000-10-13
2001-05-22
Jones, David (Department: 3725)
Metal deforming
By application of fluent medium, or energy field
With cutting
C072S325000, C072S465100, C072S466800
Reexamination Certificate
active
06233989
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a method and apparatus for forming metal sheets, and more particularly to a stamping method for punching an apertured design through a metal container lid.
BACKGROUND OF THE INVENTION
Numerous industrial, mechanical and household products require that patterns be cut into their metal surfaces. Included among such applications are metal lids that permit the diffusion of scented air from a container through a cut-out design. Such designs are commonly stamped through the top wall of the lids by a punch press apparatus. A typical press includes a die and a punch that is hydraulically moved along an axis perpendicular to the die. The punch features raised portions that mate with corresponding recesses in the punch. The mating surfaces of the die and punch correspond to the apertured design required for a given application.
During stamping, the mating portions of the die and punch shear through an interposed metal lid or sheet. More specifically, the metal workpiece is placed directly onto the die prior to stamping. As the punch is lowered and made to mate with the die, it cuts through the metal sheet as disclosed in U.S. Pat. No. 3,388,841. Elastic or laminate layers are optionally positioned between the punch and the metal workpiece to absorb tensile stresses incurred by the metal and die. Such a configuration is disclosed in U.S. Pat. No. 4,829,807.
Conventional stamping methods such as those above cause sharp edges to be formed along their stamped designs. Such exposed edges present safety concerns to assemblers and consumers. Further, known stamping techniques severely weaken the structural integrity of the lids by cutting away supportive portions of metal. Consequently, designs requiring a substantial portion of the lid to be removed are not feasible. Thus, in applications such as are described above, there is a need for an apparatus and method for stamping apertured designs into metal without substantially weakening the metal surface and exposing sharp edges.
SUMMARY OF THE INVENTION
This invention is directed to a method and apparatus for stamping a metal sheet with an apertured design. According to the invention, a cushioning pad is placed onto a die and metal sheet is positioned between the pad and a perforating punch that is operable to mate with the die. The punch is used to cut through the metal sheet and pad to stamp the metal sheet with the design and roll the metal edges of the design.
The cushioning pad is made of vegetable or polymeric fibers and is of variable thickness. For example, polyester, polyamide (aramid) and treated paper fibers bound with nitrite, neoprene and SBR are particulary effective. The apertured design may embody any polygonal or decorative shape, including a swirl pattern. Significantly, the edges of the apertured design are rolled over to reinforce the metal and to avoid sharp cutting surfaces.
The present invention is especially used to stamp a metal container lid with an apertured design having curled edges with superior strength characteristics as compared with lids that have flat-cut edges. For example, a swirl design with rolled edges provides a functionally effective and aesthetically pleasing design for dispensing aroma through the apertures. Additional features of the metal container lid include an absence of sharp edges on the top surface of the cap, as well as enhanced strength characteristics. Thus, more material may be cut out of the metal surface without sacrificing the integrity of the lid.
The above and other objects and advantages of the present invention will be made apparent from the accompanying drawings and the description thereof.
REFERENCES:
patent: 1429590 (1922-09-01), Jones
patent: 2377664 (1945-06-01), Berger
patent: 3557446 (1971-01-01), Charschan
patent: 3611765 (1971-10-01), Harvey
patent: 3678577 (1972-07-01), Weglin et al.
patent: 3683735 (1972-08-01), Achler et al.
patent: 3888841 (1968-06-01), McHardy et al.
patent: 3986379 (1976-10-01), Mansell
patent: 4509358 (1985-04-01), Krowl
patent: 4574445 (1986-03-01), Bentin et al.
patent: 4601189 (1986-07-01), Langenhorst
patent: 4748837 (1988-06-01), Kurosawa et al.
patent: 4765166 (1988-08-01), Bergman et al.
patent: 4770015 (1988-09-01), DeSmet
patent: 4829807 (1989-05-01), Nacke
patent: 5016458 (1991-05-01), DeSmet
patent: 5255550 (1993-10-01), Dittlo
patent: 5272898 (1993-12-01), Dittlo et al.
patent: 5361617 (1994-11-01), Dittlo
patent: 5460787 (1995-10-01), Colon
patent: 5755129 (1998-05-01), Yamasaki
patent: 6029486 (2000-02-01), Haraga et al.
Changing Paradigms, LLC
Jones David
Wood Herron & Evans L.L.P.
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