Metal deforming – Process – Deforming sheet metal
Reexamination Certificate
2000-02-18
2001-08-07
Larson, Lowell A. (Department: 3725)
Metal deforming
Process
Deforming sheet metal
C029S011000
Reexamination Certificate
active
06269672
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method for controlling the curling of metals. More specifically, this invention relates to a method of fabricating a metal device such as a hinge, wherein indentations are made in a metal work piece to control the curling aspect of the metal being worked on.
2. Description of Related Art
The related art of interest describes various methods and apparatus for bending metal workpieces, but none describes the present invention of forming specific indentations to improve the curling process. The related art will be discussed in the order of perceived relevance to the present invention.
U.S. Pat. No. 5,062,286 issued on Nov. 5, 1991, to Bengt I. G. Sjöblom describes a method and apparatus for bending a corrugated sheet transversely of the corrugations in which the valleys of the corrugated sheet are clamped against a die in an edging press device by tongues of a pressfoot while a fold line or weakening is pressed, in the form of an indentation into the corrugations' crests by a bar. The fold line or weakening enables the sheet to be subsequently bent to a desired angle over the edge of a bench or support surface. The method and apparatus are distinguishable for bending a corrugated metal sheet.
U.S. Pat. No. 5,051,294 issued on Sep. 24, 1991, to Michael J. Lunkas et al. describes a catalytic converter substrate and assembly formed of steel sheets embossed with corrugations in a chevron pattern such that the metal buckles at the vertices of the adjoining corrugations to form projections extending out of the plane of the sheet. The sheets are stacked with the projections registered to form weld points, and capacitive discharge welding secures the sheets together. The substrate is formed into two halves which are clamped together and secured by end rings. The catalytic converter substrate is distinguishable for forming vertices to buckle the corrugated sheet to form projections for weld points.
U.S. Pat. No. 4,380,573 issued on Apr. 19, 1993, to Gustav Näslund describes a method and device for bending section-sheet having corrugations of longitudinal and parallel ridges and valleys by introducing impressions transversely across the corrugated ridges. The method and device are distinguishable for treating only corrugated metal.
U.S. Pat. No. 1,197,271 issued on Sep. 5, 1916, to Ferdinand Dieckmann describes a method of producing sheet metal elbows from cylindrical, rectangular and corrugated metal pipes. Initially, a cylindrical metal pipe has hemispherical crimps made to form the elbow which is then processed by dies to form rectangular corrugated pipes. The method is distinguishable for preforming crimps in cylindrical pipes to form the elbow prior to subsequent forming of rectangular corrugated pipes.
U.S. Pat. No. 4,748,838 issued on Jun. 7, 1988, to Richard C. Cornelison describes a process for making obliquely corrugated thin metal strips by passing a thin metal strip through corrugating helical rolls for impressing a series of single apex, V-shaped chevron corrugations by which the strip can be split into two strips along the apices of the chevrons. The process is distinguishable for forming a chevron design for splitting a strip lengthwise.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
The present invention is a method of curling a first metal portion of a planar workpiece over a second cooperating curled workpiece to produce a device such as a door hinge, a lid and the like. The present method includes forming indentations on the inside surface of the first metal portion.
Accordingly, it is a principal object of the invention to provide an innovative method of effectively curling metal portions of a planar workpiece.
It is another object of the invention to provide a method of curling metal portions of a planar workpiece by either a curling tool or roll forming.
It is a further object of the invention to provide a method of curling metal portions of a planar workpiece by forming indentations, wherein several indentations can be combined and the depth of the indentations can be varied.
Still another object of the invention is to provide a method of curling metal portions of small parts and of various thicknesses.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
REFERENCES:
patent: 846139 (1907-03-01), Pruden
patent: 1197271 (1916-09-01), Dieckmann
patent: 1810716 (1931-06-01), Locke
patent: 4380573 (1983-04-01), Näslund
patent: 4748838 (1988-06-01), Cornelison
patent: 5051294 (1991-09-01), Lunkas et al.
patent: 5062286 (1991-11-01), Sjöblom
patent: 2 197 810 (1988-06-01), None
patent: 54-2260 (1979-01-01), None
Larson Lowell A.
Litman Richard C.
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