U.S. patent number 3,857,270 [Application Number 05/412,864] was granted by the patent office on 1974-12-31 for method of shaping sheet material.
This patent grant is currently assigned to Philip Morris Incorporated. Invention is credited to Clemens A. Iten.
United States Patent |
3,857,270 |
Iten |
December 31, 1974 |
METHOD OF SHAPING SHEET MATERIAL
Abstract
The subject matter concerns a method of shaping sheet material
in the fabrication of articles therefrom having modified corner
areas resulting from bending the sheet to a desired shape of the
product, the sheet being relieved, that is, thinned down, prior to
bending on the ultimate inside of the bend whereby the
corresponding corner area at the apex of the angle is drawn in and
sharp corners are avoided or suitably reduced.
Inventors: |
Iten; Clemens A. (Staunton,
VA) |
Assignee: |
Philip Morris Incorporated (New
York, NY)
|
Family
ID: |
23634805 |
Appl.
No.: |
05/412,864 |
Filed: |
November 5, 1973 |
Current U.S.
Class: |
72/324;
72/379.2 |
Current CPC
Class: |
B21D
5/00 (20130101) |
Current International
Class: |
B21D
5/00 (20060101); B21d 005/00 () |
Field of
Search: |
;72/324,341,379
;113/116R,116A,116F |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Larson; Lowell A.
Attorney, Agent or Firm: Watson Leavenworth Kelton &
Taggart
Claims
What is claimed is:
1. A method of shaping sheet material comprising relieving the
material at an area at one side of the sheet, and bending the sheet
about an axis through said area with the area on the inside of the
bend, thereby drawing in the sheet material at the apex of the
angle formed by the bend.
2. A method of shaping sheet material in accordance with claim 1 in
which the relieved area is at an edge of the sheet extending
inwardly a substantial distance therefrom.
3. A method of shaping sheet material in accordance with claim 1 in
which the relieved area is of limited width and located entirely
within the edges of the sheet along said axis and the drawn in area
is accordingly entirely within the edges of the sheet.
4. A method of shaping sheet material in accordance with claim 1 in
which the drawn in area at the apex decreases progressively into
the sheet as the relieved area merges into the unrelieved areas of
the sheet.
5. A method of shaping sheet material in accordance with claim 1 in
which an opening is preformed in the sheet at an edge of the
relieved area extending through the apex of the angle and the drawn
in area at the apex is substantially uniform in amount extending
into said opening.
6. A method of shaping sheet material in accordance with claim 1 in
which said material is of a character having substantial
ductility.
7. A method of indenting inwardly the corner area of a bent sheet
of material comprising relieving the material on one side of the
sheet at an area to become said corner area, and bending the sheet
through said relieved area with the area on the inside of the bend.
Description
The invention concerns a method of shaping sheet material
particularly directed to producing an indented corner. Under normal
conditions of shaping by bending a sheet material a sharp corner
area commonly results which in the further operations of
fabricating the intended article may interfere with the automatic
machine manipulations. Also such corner shapes often are
undesirable in the final product from the standpoint of appearance
and comfort in handling. Accordingly, various operations have been
employed to reduce the corner area such as by machining off or
coining or stamping down the external surface at the corner either
prior to or after its formation. Such operations however usually
complicate the fabricating operations and add to the overall cost
and manufacturing steps.
The present invention provides a very effective and much simplified
procedure for accomplishing the corner indentation. Basically, it
embodies the step of relieving in advance the area at the eventual
apex of the angle formed by the bend on the side which becomes the
inside of the angle formed by the bending step. The operation of
relieving the area may be any one of known mechanical steps such as
by cutting away material at the critical area or by stamping or
coining. As a result, the stresses produced by the bending are such
as to cause the remaining thinner area to be automatically drawn in
at the apex of the angle thereby indenting the corner below the
normal outer surface of the sheet at that area.
The principles of the invention and the physical phenomena will be
made more fully apparent from representative applications as
described hereinafter and depicted in the drawings in which:
FIGS. 1a, 1b and 1c illustrate the basic features of the invention.
FIG. 1a being a section of the original flat sheet material, FIG.
1b showing the material bent around the relieved area and FIG. 1c
is a cross-sectional view taken on the plane I c - of FIG. 1b.
FIGS. 2a to 2d illustrate another application of the principles of
the invention in which FIG. 2a is a section of the original sheet
material, FIG. 2b shows the sheet is formed into a part having two
angles, and FIGS. 2c and 2d are cross-sections taken on the planes
II c and II d respectively of FIG. 2.
FIGS. 3a to 3c correspond to FIGS. 1a to 1c respectively and show a
different form of relieved area.
FIG. 4a is a view in perspective of a shell for an injector blade
dispenser embodying the features of the invention; and FIG. 4b is
an end view thereof on an enlarged scale.
FIGS. 5a to 5c correspond to FIGS. 1a to 1c but include an opening
through the sheet material in association with the relieved
area.
FIGS. 6a to 6c likewise correspond to FIGS. 1a to 1c but illustrate
a tapered form of relieved area.
Referring to FIGS. 1a to 1c which illustrate the basic features of
the invention, FIG. 1a depicts a section of sheet material 10
having a relieved area 11 on one side, the area in this case being
half moon shape. The relieved area may be formed in any suitable
manner as by machining away the area or by coining or stamping. The
method may be applied to any desired sheet material having for best
results substantial ductility as, for example, a metal such as
aluminum, iron or copper or alloys thereof. The sheet is bent into
a desired angle needed for the ultimate product, FIG. 1b showing it
bent 90.degree. into a right angle about an axis 12. The relieved
area 11 corresponds to the compression side of the neutral axis 13
and the remaining area 14 at the apex of the angle comprises the
tension area. As the plastic deformation occurs the tensed area 14,
due to the resulting vector forces, displaces inward toward the
bend axis as illustrated in FIG. 1b resulting in an indentation 15
extending around the apex of the angle. The indentation decreases
progressively as the area 11 merges into the adjacent unrelieved
areas of the sheet.
The precise final shape or result depends upon factors which may be
varied such as the ductility of the material, the bend angle and
the configuration of the relief, that is the depth, width and
length. For purposes of description and understanding, it may be
noted that the relief length in FIG. 1 is indicated by the
dimension 16 and may be defined as the total distance of the relief
along the bend axis, and the relief width may be defined as the sum
of the distances at each side from the bend axis perpendicular to
the axis indicated by the dimension 17 in FIG. 1a.
With respect to the depth of the relief, if the material has been
relieved to or past the neutral axis, the remaining area 14 is
completely under tension and if relieved only part of the distance
to the neutral axis it is predominantly under tension.
In the application of the invention illustrated in FIGS. 2a to 2d,
the relieved area 20 is more extended in width than in FIG. 1a and
the sheet is bent at two areas of different angle resulting in the
indented corner areas 21 and 22.
FIGS. 3a to 3c illustrate the invention in which the sheet 30 has
the full basic material thickness at each side of the relieved area
31. In other words, the relieved area 31 is spaced entirely
inwardly from the opposite edges 32 and 33 of the sheet 30
resulting in an intermediate indented area 34. Similarly to the
effect produced in the preceding forms, the indented area reduces
progressively as it merges into the adjacent portions of the sheet
as indicated at 34a.
Thus far the disclosure has been directed to the general principles
of the invention as an indication of a manner in which it may be
applied in the fabrication of various articles. FIGS. 4a and 4b
illustrate one practical application of the subject matter in the
fabrication of a shell or casing for an injector blade dispenser.
The shell 40 has corners 41 which are formed in the manner
illustrated in general in FIGS. 1a to 1c. The method results in the
avoidance or reduction of sharp or protruding corners as an
advantage in the final product; and in the manufacturing process of
shaping and loading the dispenser 40 it is of distinct advantage in
eliminating interfering engagement or hang-up at stages in the
shaping and handling and loading of the dispenser.
Various other applications of the invention may be employed. FIGS.
5a to 5c illustrate a sheet 50 having a relieved area 51 and an
opening through the sheet material at 52 in a form in this case of
a slot, the slot extending through the bend axis 53 at the apex. As
a result, after bending, the indentation 54 at the corner is
uniform because of the interruption at the opening 52 as
distinguished from the progressive tapered draw-in shape shown in
the previous examples.
FIGS. 6a to 6c illustrate the result with a tapered relief. In
other words, the sheet 60 has a relief 61 which is tapered as
indicated particularly in FIG. 6c at 62 which results in a tapered
indentation 63 which is at a maximum at the extreme edge 64.
Various applications of the principles of the invention have been
described above and illustrated in the drawings and it will be
apparent that further variations may be resorted to dependent upon
the circumstances and accordingly it is intended that all matter
contained herein shall be interpreted as illustrative and not in a
limiting sense.
* * * * *