Sheet metal container making – Method – Assembling receptacle with closure
Patent
1997-05-13
1999-09-07
Coan, James F.
Sheet metal container making
Method
Assembling receptacle with closure
413 6, 413 7, 53488, B21D 5132, B65D 630
Patent
active
059476737
DESCRIPTION:
BRIEF SUMMARY
The technical field of the invention is the providing of a seam on a can body closed with a (can) end, such as beverage or food can made from sheet material. The function of such a seam is to hold the can end and the can body tightly together to protect them also against relatively high forces possibly becoming effective from outside, e.g. by pressure or shock, and from inside, e.g. by high or low pressure, and moreover, to hermetically air-seal the content of the can.
Whereas the seam was soldered for sealing purposes in former times, it has been usual a long time now to introduce a sealing compound into the seam and to close the seam without soldering (compare FIG. 1 of DE-A 21 34 034; FIG. 3 of EP-A 445 721; FIG. 2 of FR-A 2 327 149; FIG. 12 of U.S. Pat. No. 4,626,158; FIG. 6 of U.S. Pat. No. 2,327,424).
An object of the invention is to improve the characteristics of such a seam with regard to its mechanical stability as well as with regard to a realiable and durable hermetical sealing; consequently, the stability of the seam shall be improved, particularly when using metal sheets having a reduced thickness compared to presently used sheets with a thickness of about 0.24 mm.
According to claims 1, 9 or 12 this object is solved by appropriately designing the seam geometry with the seam geometry being improved according to the present invention, thinner metal sheets may be used for the production of at least one of the can body or the can end, providing equal stability and tightness, or--when using metal sheets of usual thickness--a substantially higher stability and a hermetical sealing of even higher reliability may be obtained. Said high stability is achieved by a stronger clamping or squeezing and (inter)locking of the seam elements in a limited portion of the seam height. Thus, the seam receives a higher stability which also permits the use of metal sheets of reduced thickness (claim 8).
The hermetical sealing is also improved by said increased clamping or squeezing.
The additional clamping or squeezing and (inter)locking being effected only in the lower portion of the seam, the compound material is prevented from moving away from the upper seam portion when the seam is shaped. With the new seam geometry a direct contact of metal sheets in the upper end portion of the seam is avoided, so that the compressed sealing compound performs its hermetical sealing function better than in case of a direct metal-to-metal contact (claim 5).
In a preferred embodiment,--in a readily shaped seam--the lower and outer portion of the can end hook is in firm, particularly in surface contact (positive fit) with the surface portion located above the free end of the body hook, whereas the upper portion of the can end hook being close to the edge of the seam is markedly offset in radially outward direction with respect to said lower portion, thus being spaced apart from the adjacent metal sheet portion of the body hook (claim 6). Thus, a contoured outer seam surface is provided, said two mentioned upper and lower portions being interconnected continuously or by a preferably smooth step (claim 2).
Consequently, the firm pressure adhesion, preferably the pressure contact (positive fit) of the metal sheet portions only extends along the lower seam portion (claim 6). Said lower seam portion has substantially cylindrical extension (claim 7). It decouples the width b of the seam from the length tolerance of the body hook.
The seam geometry can at any time be examined and determined by a making a cut through the seam of a closed can.
In addition to the improvement of the seam, the invention permits the use of thinner metal sheets than usual today. The application of surface pressure contact to the portions of the metal sheets in the lower half to the lower third of the seam may reach so far that a mechanical locking is provided at the lower edge of the body hook. The entire seam is of markedly higher stability, namely for both the use of usual metal sheets and the use of metal sheets with reduced thickness.
The surface pressure c
REFERENCES:
patent: 2327424 (1943-08-01), Henchert
patent: 3688464 (1972-09-01), Fox
patent: 4037550 (1977-07-01), Zofko
patent: 4626157 (1986-12-01), Franek et al.
patent: 4626158 (1986-12-01), Le Bret
patent: 5054265 (1991-10-01), Perigo et al.
1936, W. Friebel Handbuchder, Dosenfertigung, pp. 82 & 83.
PCT International Preliminary Examination Report.
1953, P.Aurich, Verbinden von Blech Durch Falzen--II. Teil, pp. 507-511.
1958, Von Edmund G. Blake, Verschliefmaschinen-Einsstellungen, pp. 45-54.
Coan James F.
Schmalbach-Lubeca AG
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