U.S. patent number 3,690,137 [Application Number 05/047,026] was granted by the patent office on 1972-09-12 for roll forming of sheet metal.
This patent grant is currently assigned to Cookson Sheet Metal Developments Limited. Invention is credited to William Cookson.
United States Patent |
3,690,137 |
Cookson |
September 12, 1972 |
ROLL FORMING OF SHEET METAL
Abstract
Method and apparatus for forming sheet metal to a desired
profile in draw forming rolls in which in a first roll stand an
easily drawn curved initial rib is produced and in a second roll
stand the rib is reshaped, for example into a pair of ribs. The
method is repeated to one or both sides of the initial deformation
to make further profiles, at least one further initial rib being
formed in the second roll stand to one side of the first initial
rib.
Inventors: |
Cookson; William (Fareham,
EN) |
Assignee: |
Cookson Sheet Metal Developments
Limited (Southampton, EN)
|
Family
ID: |
10320766 |
Appl.
No.: |
05/047,026 |
Filed: |
June 17, 1970 |
Foreign Application Priority Data
|
|
|
|
|
Jun 20, 1969 [GB] |
|
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31,280/69 |
|
Current U.S.
Class: |
72/180 |
Current CPC
Class: |
B21D
5/08 (20130101); B21D 13/045 (20130101) |
Current International
Class: |
B21D
13/00 (20060101); B21D 5/06 (20060101); B21D
13/04 (20060101); B21D 5/08 (20060101); B21d
005/16 () |
Field of
Search: |
;72/180,176,179 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Mehr; Milton S.
Claims
What is claimed is:
1. A method of shaping sheet metal in a single pass through a
plurality of roll stands each having cooperating forming rolls to
form a plurality of longitudinally extending profiles spaced
laterally across the sheet, each profile being formed by the
reforming in at least one roll stand of an initial rib, comprising
the steps of,
a. forming a first initial rib in a first roll stand,
b. reforming the said first initial rib and forming at least one
further initial rib laterally of the said first initial rib in a
second roll stand, and
c. transforming as the sheet approaches each respectively of the
said first and second roll stands at least a portion of the sheet
into a valley cross-section, the apex portion of which is formed
into the respective initial rib as the sheet passes through the
respective roll stand, the valley cross section having a width
greater than that of the initial rib,
each of the said initial ribs containing sufficient metal that the
profile which is to be formed subsequently from it can be formed
without further drawing in of metal from the rest of the sheet.
2. A method according to claim 1 wherein two of the said further
initial ribs are formed in the second roll stand, one to each side
of the said first initial rib.
3. A method according to claim 1 wherein each of the profiles
subsequently formed from the said initial ribs is a pair of ribs,
the said first initial rib being reformed into a pair of ribs in
the second roll stand and the said at least one further initial rib
being reformed into a pair of ribs in a third roll stand.
4. A machine for the draw roll forming of a plurality of
longitudinally extending profiles in a metal sheet passed
continuously through the machine including
a first roll stand having cooperating male and female forming
rolls,
a second roll stand having cooperating male and female forming
rolls,
the said male forming rolls of the first roll stand having a
radially projecting part which cooperates with a radially recessed
part in the female roll of the first roll stand to form an initial
rib in the sheet as it passes through the first roll stand,
the said male-forming roll of the second roll stand having at least
one radially projecting part which cooperates with a radially
recessed part of the female roll of the second roll stand to form a
further initial rib in the sheet as it passes through the second
roll stand, the further initial rib being spaced laterally from the
said first initial rib,
the said rolls of the second roll stand having cooperating parts
which reform the said initial rib formed by the first roll stand
without drawing in further metal from the rest of the sheet,
there being an axially extending coaxial support flange adjacent
each side of each said radially projecting part, the diameter of at
least one of the support flanges adjacent each said radially
projecting part decreasing with distance from the said radially
projecting part, the radially projecting part and the support
flanges of the male roll and the radially recessed part on the
female roll assisting in the transformation of the sheet as it
approaches the roll stand into a valley cross-section having an
apex portion which provides the strip of sheet from which the
initial rib is formed as it passes through the roll stand.
5. A machine according to claim 4 wherein the said radially
projecting part on each of the said male forming rolls has an
arcuately curved periphery as seen in axial cross-section whereby
the initial rib formed has an arcuate cross-section.
6. A machine according to claim 4 wherein each of the said female
forming rolls has a coaxial flange at each side of the said
radially recessed part, which flanges are opposed to and parallel
to the said flanges of the respective male rolls in the nip of the
male and female rolls, the flanges being spaced in the nip to allow
metal to be freely drawn in laterally during the formation of the
initial rib.
7. A machine according to claim 4 wherein the said cooperating
parts of the rolls of the second roll stand which reform the
initial rib formed in the first roll stand, are shaped to form a
pair of ribs from the initial rib, there being a third roll stand
having rolls including cooperating parts which reform the said at
least one initial rib formed in the second roll stand into a
further pair of ribs.
8. A machine according to claim 4 wherein the male roll of the
second roll stand has two of the said radially projecting parts,
one to each side of the part which reforms the initial rib made in
the first roll stand, whereby two further initial ribs are formed
in the second roll stand.
Description
This invention relates to a machine and a method for shaping sheet
metal especially by cold draw roll forming and more particularly
for forming and reshaping ribs in sheet metal.
In U.K. Pat. No. 950,059 there is described and claimed a method of
forming a deep rib in a metal sheet, by means of co-operating
rib-forming rolls, said method comprising deforming to a valley
cross-section a longitudinal portion of a sheet having a width
substantially greater than the width of the strip of the sheet from
which the rib is to be formed and having as its apex the said strip
from which the rib is to be formed, and acting on the said strip
with one pair of co-operating rib-forming rolls to form a deep rib
at a single pass through the said one pair of rolls.
There is also described and claimed in the said patent a machine
for the continuous formation of a longitudinal rib in a metal sheet
by the action of rib-forming rolls (the width of the sheet being
substantially greater than the strip from which the rib is to be
formed) said machine having means for supporting the sheet, before
entry into the rolls, at a level substantially lower than the nip
of the rolls so that, as the sheet approaches the rolls it is
gradually transformed into a shape having a valley cross-section,
the apex of the said valley section providing the strip from which
the deep rib is formed as it passes through the rolls, means being
provided, after the rib-forming rolls, to cause the valley section
(save for the rib) to recover to the flat plane of the finished
profile.
According to the present invention there is provided a method of
shaping sheet meal in a single pass through a plurality of roll
stands each having cooperating forming rolls to form a plurality of
longitudinally extending profiles spaced laterally across the sheet
each profile being formed by the reshaping in at least one roll
stand of an initial rib wherein a first initial rib is formed in a
first roll stand,
THE SAID FIRST INITIAL RIB IS REFORMED IN A SECOND ROLL STAND IN
WHICH AT LEAST ONE FURTHER INITIAL RIB IS FORMED LATERALLY OF THE
SAID FIRST INITIAL RIB,
EACH OF THE SAID INITIAL RIBS CONTAINING SUFFICIENT METAL THAT THE
PROFILE WHICH IS TO BE FORMED SUBSEQUENTLY FROM IT CAN BE FORMED
WITHOUT FURTHER DRAWING IN OF METAL FROM THE REST OF THE SHEET,
AS THE SHEET APPROACHES EACH RESPECTIVELY OF THE SAID FIRST AND
SECOND ROLL STANDS, A PORTION OF THE SHEET BEING TRANSFORMED INTO A
VALLEY CROSS-SECTION, THE APEX PORTION OF WHICH PROVIDES THE STRIP
OF SHEET FROM WHICH THE RESPECTIVE INITIAL RIB IS FORMED AS THE
SHEET PASSES THROUGH THE ROLL STAND.
In the second roll stand, a further initial rib may be formed to
each side of the first initial rib while the latter is reshaped.
Preferably the initial ribs have an arcuate cross-section and are
bounded by longitudinally extending parallel bend-lines.
The present invention also provides a machine for the draw roll
forming of a plurality of longitudinally extending profiles in a
metal sheet passed continuously through the machine including
a first roll stand having cooperating male and female forming
rolls,
a second roll stand having cooperating male and female forming
rolls,
the said male forming rolls of the first roll stand having a
radially projecting part which cooperates with a radially recessed
part in the female roll of the first roll stand to form an initial
rib in the sheet as it passes through the first roll stand,
the said male-forming roll of the second roll stand having at least
one radially projecting part which cooperates with a radially
recessed part of the female roll of the second roll stand to form a
further initial rib in the sheet as it passes through the second
roll stand, the further initial rib being spaced laterally from the
said first initial rib,
the said rolls of the second roll stand having cooperating parts
which reform the said initial rib formed by the first roll stand
without drawing in further metal from the rest of the sheet,
there being an axially extending coaxial support flange adjacent
each side of each said radially projecting part, the diameter of at
least one of the support flanges adjacent each said radially
projecting part decreasing with distance from the said radially
projecting part, the radially projecting part and the support
flanges of the male roll and the radially recessed part on the
female roll assisting in the transformation of the sheet as it
approaches the roll stand into a valley cross-section having an
apex portion which provides the strip of sheet from which the
initial rib is formed as it passes through the roll stand.
Each initial rib formed in the metal may be re-shaped to the
desired profile above, below or partly above and partly below the
plane of the sheet within the confines of the material between bend
lines at the edges of the initial rib.
The invention further includes draw forming rolls suitable for
performing the above method.
Various forms of the invention will now be described with reference
to the accompanying drawings wherein:
FIG. 1 shows in perspective view a first initial rib being draw
roll formed in a sheet by a first pair of rolls;
FIG. 2 shows a cross-section view of the rolls of FIG. 1 with the
formed metal sheet interposed therebetween;
FIG. 3 shows in perspective view the sheet formed in the first
rolls being re-shaped in a second pair of rolls part of the rolls
only being shown;
FIG. 4 shows a cross-section view of the part of the rolls shown in
FIG. 3 with the re-shaped metal interposed therebetween;
FIG. 5 shows a cross-section view of a reshaped portion of the
sheet after passage through the rolls of FIG. 3;
FIG. 6 shows the final cross-section of the sheet shown in FIG.
5;
FIG. 7 shows further parts of the rolls shown in FIG. 3, which
parts form the two initial ribs shown at the sides of the
cross-section in FIG. 5; and
FIG. 8 shows the cross-section of another profile re-shaped from
the initial rib shown in FIG. 2.
FIGS. 1 to 4 and 7 of the drawings show pairs of co-operating
forming rolls for carrying out the method of the invention mounted
on suitable shafts as provided in two consecutive roll stands (not
shown for clarity) of a cold roll forming machine of known
construction comprising a number of roll stands in spaced tandem
relationship, the rolls being suitably powered to progressively
roll form continuous metal strip to a desired profiled section. In
conventional machines a considerable number of stands with the
appropriate forming rolls are required for this purpose because the
metal strip is progressively formed from the strip in a flat
condition the successive rolls only gradually shaping the metal by
pressure-forming within the dimensional limits of the desired
section. The draw roll forming process as described in our U.K.
Pat. No. 950,059 (and in U.S. Pat. No. 3,184,942) is a different
method of forming in which the metal strip, prior to and during its
passage through the machine is temporarily deformed to intermediate
transitory shapes occupying a space considerably outside the
dimensional limits of the finished section. The process reduces the
number of roll stands and rolls and the present invention also
decreases these, the method involving additional shaping in the
draw roll forming rolls.
FIG. 1 shows a first pair of co-operating forming rolls in a first
stand and in FIGS. 3, 4 and 7 are shown constituent parts of a
second pair of co-operating forming rolls mounted at a suitable
distance in the machine behind the first pair of rolls. A further
roll stand is provided behind the second stand at a suitable
distance as subsequently explained, the machine thus comprising
three powered roll stands with the appropriate forming rolls. The
section which is formed from continuous metal sheet is shown in
FIG. 6 and comprises a roofing sheet 18 having six ribs of
trapezoidal section. It will be noted by those skilled in the art
that this example of the draw roll forming process only requires
three pairs of rolls and roll stands to roll form the desired
profile instead of at least twelve pairs of rolls and roll stands
which would be required in the case of the conventional
machines.
In FIGS. 1 and 2 a continuous metal sheet 18 is uncoiled preferably
from an uncoiler (not shown) and is drawn through a male roll 10
and a female roll 12 mounted on shafts 40, 42 in a first roll
stand. Male roll 10 which acts as a plunger roll has a pair of
support flanges 14 flanking a central plunger part 28. The flanges
14 are disposed at an angle to each other and the two rolls in
combination form in the strip 18 a curved transient valley section
32 having walls 16. The angle between the walls 16 is equal to the
angle between the flanges 14.
Female roll 12 may have a pair of support flanges 20 disposed at a
complementary angle to flanges 14 so that the surfaces of flanges
14, 20 where they co-operate are parallel to each other.
Alternatively the female roll 12 may have a pair of disc flanges 22
as denoted by dotted lines 24 in FIG. 2. The female roll acts as a
die roll having an annular recess 30 between the flanges 20 or 22.
The parts of the rollers disposed between the flanges 14 and 20
respectively i.e, the plunger part 28 and the recess 30 are
intended to form an initial curved rib 26 in the sheet 18 and hence
will be called shaping parts. The initial rib is formed in a strip
of the sheet at the apex of the valley section 32, this strip being
narrower than the material in the valley section as a whole. It
will be appreciated that the cross-section of the shaping parts and
the angles and position of the supporting flanges are such that the
two rollers mate to maintain valley section 32 in the sheet as the
sheet passes through the rolls. The edge portions 34 of the valley
section 32 are temporarily deformed downwardly out of the flat
plane of the sheet during the passage of the sheet through the
rolls, the edge portions in the process becoming sufficiently
semi-resilient to allow the metal sheet to be freely drawn
laterally through the rolls to form the curved rib 26.
The forming rolls 10 and 12 form the easily shaped curved rib
cross-section 26 in the sheet 18. As they leave the rolls 10, 12
the walls 16 of the sheet 18 gradually recover to the flat plane of
the sheet to become flat walls 36. It will be understood that the
valley section 32 provides a transitory free drawing shape which is
considerably deeper than the depth of the cross-section of the rib
26 and flat walls of the sheet.
Parallel bend lines 38 define the area in which the curved rib 26
has been shaped between the flat walls 36 of sheet 18. The object
of the first rolls is to draw form a shape most suitable for
providing the required material in a middle portion of a sheet and
this is next re-shaped between the bend lines to the desired final
profile without causing any distortion in the remaining portions 36
of the sheet.
In FIGS. 3, 4 and 7 4 are shown two pairs of rib-forming rolls
having shafts 52,54 carrying male roll 44 parts and 46 and female
roll parts 48 and 50 for re-shaping curved rib 26 into the desired
profile within bend lines 38. The shafts 52,54 also carry roll
parts to each side of the parts 44, 46, 48, 50 as will be described
below. In this example the roll parts 44, 46, 48, 50 are provided
with trapezoidal shaping parts. The rolls are mounted in a second
stand of the machine situated behind the first roll stand (not
shown for clarity). Male roll parts 44,46 and female roll parts
48,50 are mounted on shafts 52 and 54 and are made to match
together with a suitable clearance to allow sheet 18 to pass
between them and to form trapezoidal ribs 56 and 58 (See also FIG.
5).
Referring to FIG. 5 further curved initial ribs 60, 62 are formed
in the second roll stand, one on each side of the portion of the
sheet which has already been shaped. Alternatively, a single curved
rib to one side only could be made. The ribs 60, 62 are to enable
the formation of further desired profiles e.g., the two lateral
pairs of ribs 64, 66 and 68, 70 shown in FIG. 6.
Suitable apparatus for forming the further initial ribs 60, 62 is
shown in FIG. 7 which illustrates the sheet 18 passing between roll
parts 90, 92 in a roll stand. The roll parts 90, 92 are mounted on
shafts 52, 54 of the second roll stand so that the male roll parts
90a, 90b lie one on each side of male roll parts 46, 44
respectively and the female roll parts 92a, 92b one on each side of
the female roll parts 50, 48 respectively.
Each pair of co-operating male and female roll parts 90a, 92a and
90b, 92b is generally similar to the rolls in FIG. 2 having similar
shaping parts 94, 96 and similar support flanges 98, 100 on the
side of the rolls away from the initial rib 26 which is being
re-formed in the roll parts 44, 46; 48, 50. The support flange 98
on the male roll has a diameter which decreases with distance from
the mid plane of the roll and the corresponding flange 100 on the
female roll is either parallel to it at the nip or is cylindrical
as indicated by the dotted line 102. The coaxial support flanges
104, 106 on the side towards the portion of the sheet which has
already been shaped, are preferably both cylindrical as indicated
so that the nip between them is parallel to the roll axles
(preferably horizontal) and the part of the sheet indicated at 108
which is between the portion which has already been shaped and the
further initial rib being formed has a similar disposition. A
valley cross section is formed in advance of each of the roll parts
90a, 92a and 90b, 92b. As the valley passes through the rolls, it
will be seen to be curved in the center and to have one horizontal
wall 108 and one downwardly deflected wall 110. Material required
for the valley formation may be freely drawn inwardly from the edge
of the sheet. A strip of the sheet at the apex of the valley
section and narrower than the width of the valley section is formed
into the initial rib 62 or 60.
It will be apparent that when only one further initial rib is to be
formed, only one pair of roll parts 90a, 92a or 90b, 92b is
needed.
Curved ribs 60, 62 are re-shaped in a subsequent stand comprising
two sets of roll parts each of which is similar to roll parts 44,
46 and 48, 50. By such means the desired final profile in FIG. 6 is
achieved comprising the six trapezoidal ribs indicated in sheet 18
by using only three stands in the machine.
Where deep ribs are required, the initial ribs can be re-formed in
two stages. For example, a first stand can make a first initial rib
as indicated in FIG. 1 and rolls in a second stand can partly
re-form the initial rib and can make further initial ribs on either
side. A third stand having rolls similar to the rolls in FIG. 3 can
complete the re-forming of the first initial rib and can contain
rolls to begin re-forming the new initial ribs formed in stand 2. A
fourth stand can complete the reforming of the new initial ribs to
the desired profile.
Further stands can be provided to make more ribs if desired.
The machine illustrated is adapted for continuous forming of ribs
in sheet metal.
The method of first making an easily formed shape in a portion of a
sheet by temporarily providing a semi-resilient edge portion on at
least one side from which material can be laterally drawn through
the rolls with the easily formed shape defined between two parallel
bend lines gives the opportunity of re-shaping the material between
said bend lines to provide cross-sections of varying profiles
including profiles of complex cross-section in a minimum number of
roll stands. The sheet metal can thus be readily drawn into
suitable transitory shapes without the risk of splitting of the
material or damaging its surfaces, particularly when precoated
painted sheet is used and the said shapes may be re-shaped
subsequently between the bend lines also without causing any damage
to the material.
As in the present example, the initial rib should provide all the
material required, between the bend lines, for the finally desired
profile so that no further drawing in of metal is required and
other parts of the sheet can be operated on while the initial rib
is being re-shaped without disturbance from this re-shaping action.
Successive contraction of parts of the sheet towards the center
after the formation of an initial rib in those parts can therefore
be avoided.
In FIG. 8 is shown an example of an alternative profile a plurality
of which can be formed in a sheet by the method of the invention.
It is a complex profile and is formed in a sheet 72, firstly by
draw rolling the curved rib 74 (shown dotted) in the middle portion
of the sheet between parallel bend lines 76 and secondly by
re-shaping the material between said lines to form a slightly
curved base 78 below the plane of the sheet 72 and two upstanding
swages 80 and 82 as shown.
* * * * *