Metal deforming – By use of tool acting during relative rotation between tool... – With cutting of work or product
Patent
1992-03-03
1994-03-29
Larson, Lowell A.
Metal deforming
By use of tool acting during relative rotation between tool...
With cutting of work or product
B21D 5140
Patent
active
052974111
DESCRIPTION:
BRIEF SUMMARY
This invention relates to metal deformation and particularly but not exclusively to a method of forming a cylindrical, internally threaded opening in an end wall of a metal, preferably mild steel, container drum.
It is known to provide cylindrical openings in the end walls of container drums by fitting a pre-fabricated insert into the end wall. This is disadvantageous because of the additional costs involved in pre-fabricating and fitting the insert. It is therefore one object of the present invention to provide a method of forming an integral cylindrical opening in the container drum end wall and forming an internal screw-thread on said opening. More generally, it is an object of the present invention to provide a method of forming a screw thread on any internal cylindrical surface.
According to a first aspect of the present invention there is provided a method of forming a cylindrical opening in a metal sheet, for example a container drum end wall, comprising piercing, pressing and drawing the metal sheet to provide a raised cylindrical section partly closed at one end by an annular flange, and bending the flange into the cylindrical section while rolling the flange so as to permit the requisite enlargement thereof.
According to a second aspect of the present invention there is provided a method of forming a screw-thread on an internal cylindrical surface, for example a cylindrical opening as produced by the method of the first aspect of the invention, comprising rolling a peripherally screw-threaded roller continuously over said surface in orbital relationship with the cylinder axis until the surface is deformed into a complementary screw configuration.
The invention will now be further described by way of example only with reference to the accompanying drawings in which:
FIG. 1 is a partly cut-away view of one end of a container drum with the end wall in section through the closure opening;
FIG. 2 is a detail of FIG. 1 to an enlarged scale, and
FIGS. 3 to 6 illustrate successive stages in the manufacture of the closure opening shown in FIG. 2.
Referring now to the drawings, FIG. 1 shows part of a cylindrical container drum made of mild steel having an end wall provided with a closure opening further illustrated in FIG. 2 as comprising a raised cylindrical section 1 of double thickness with a screw-thread 2 on the cylindrical inner surface of the inner metal skin. The outer end of the cylindrical section is thickened to provide a sealing surface 3 which is engaged by a sealing ring 4 of a conventional externally threaded bung 5 having an internal handle 6.
The closure opening illustrated in FIG. 2 is made by first piercing, pressing and drawing the metal sheet constituted by the drum end wall (prior to fixing to the drum end in conventional manner) to form a cylindrical section 7 raised out of the plane of the end wall by a step 8 and terminating at its outer end in an annular flange 9 which partly closes the cylindrical section leaving a circular opening 10 around a central axis 11 (FIG. 3).
The raised cylindrical section 7 is then surrounded by clamping supports 12 and a tool 13 is progressively introduced into the opening 10 so as to bend the flange 9 inwardly. Such deformation of the flange 9 requires a corresponding enlargement of the opening 10 which cannot be achieved without extension of the flange 9 along its circumferential dimension. Such extension is achieved by orbiting the tool 13 about the axis 11 while simultaneously rolling the frusto-conical tool surface on the flange 9 to achieve the necessary thinning of the metal in this region. When the flange 9 has been bent inwardly to an extent conforming to the shape of the tool 13, the tool 13 is replaced by a tool 14 which has a cylindrical working surface which, using the same rolling action as the tool 13, completes the inward deformation of the flange 9 and the attendant enlargement of the hole 10. The tool 14 also creates the shoulder 3 by pressing metal into a circular recess 15 in the clamping segments 12.
The cylindrical section 1 is t
REFERENCES:
patent: 2045235 (1936-06-01), Newman
patent: 2257234 (1941-09-01), Gould
patent: 2349863 (1944-05-01), Hallberg
patent: 2387990 (1945-10-01), Grosser
patent: 2460721 (1949-01-01), Thompson
patent: 2493933 (1950-01-01), Thompson
patent: 2625065 (1953-01-01), Trishman
patent: 2645954 (1953-07-01), Pfingston
patent: 2828493 (1958-04-01), Koehler
patent: 3024677 (1962-03-01), Greiman
patent: 3069939 (1962-12-01), Koehler
patent: 3069940 (1962-12-01), Koehler
patent: 3089362 (1963-05-01), Hill
patent: 3177691 (1965-04-01), Koehler
patent: 3938374 (1976-02-01), Wadsworth
patent: 4096723 (1978-06-01), Rhodes
patent: 4109600 (1978-08-01), Post
patent: 4420959 (1983-12-01), King
patent: 4426870 (1984-01-01), Toropov
patent: 4462235 (1984-07-01), King
patent: 4491002 (1985-01-01), Toropov
patent: 4498322 (1985-02-01), Toropov
patent: 4592221 (1986-06-01), Krueger et al.
Eagle Precision Technologies Limited
Larson Lowell A.
LandOfFree
Method of forming threaded opening 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 of forming threaded opening, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of forming threaded opening will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-784702