Note: Descriptions are shown in the official language in which they were submitted.
21 64999
STRETCH CONTROLLED FORMING MECHANISM AND METHOD
FOR FORMING METAL RT.A~.~
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and
apparatus for forming metal and, more particularly
to a method and apparatus that controls stretching
of blanks, such as multiple gauge welded blanks,
during forming.
2. Description of the Related Art
Recent advancements in technology have
provided blanks for stamping that are comprised of
sheet metals of various gauges having different
mechanical and chemical properties welded together
to form a single welded blank. Conventional
techniques used to weld the sheet metal components
together include laser, induction, and mash welding.
These welded blanks are of interest particularly to
the automotive industry. Welded blanks can be
formed into automotive body panels such that heavier
gauge steel is positioned where strength is
required, and lighter gauge steel is positioned
where strength is less critical. Consequently, body
panels formed from welded blanks provide weight
reduction because heavier gauge material is provided
only to those areas requiring additional strength.
Additionally, welded blanks afford a reduction in
the number of sheet metal components and welding
operations required.
Conventional stamping dies, however, are
generally incapable of producing satisfactory
21 64999
_ 2
products, including automotive body panels, from
welded blanks. Indeed, to produce products of
satisfactory quality, it is essential to deform
sheet metal blanks in a uniform manner. When
S conventional dies are used to form welded blanks,
the lighter gauge portion of the welded blank
stretches before the heavier gauge portion is
subject to deformation. At a minimum, such a
condition causes uneven stretch of the lighter gauge
material. In the worst case, conventional dies
split or wrinkle the lighter gauge material of the
welded blank during forming.
SUMMARY OF THE INVENTION
It is an objective of the present invention
to provide an apparatus and method for forming
blanks that uniformly deforms the blank.
It is a further objective of the present
invention to provide an apparatus and method for
forming welded blanks that prevents splitting or
wrinkling of the welded blank.
It is yet a further objective of the present
invention to provide an apparatus and method for
forming blanks that provides unlimited and effective
control over material flow during product formation
from metal blanks.
It is a further objective of the present
invention to provide an apparatus and method for
forming blanks that may be adapted to a variety of
configurations.
To achieve the foregoing and other objectives
of the invention, a stretch controlled forming
mechanism is provided that, in accordance with the
present invention, forms and locks a first, selected
21 64999
portion of the blank between opposed die surfaces.
In the case of a welded blank, the junction where
the different gauge materials of the blank are
welded together is formed and locked first. Such
locking prevents continued flow of material in the
locked portion during the remainder of the formation
process. Thereafter, with the selected areas
restricted from further material flow, the portion
of the blank not previously formed is formed between
the remaining opposed surfaces of the dies.
Thus, in accordance with the present
invention, a first set of opposed dies having
opposed die surfaces is provided. One or all of
those dies are movable relative to the others in a
conventional manner. Disposed adjacent to or
bounded by one of the dies of the set is a floater
assembly, also having an opposed die surface. In a
first embodiment of the invention, as described
below, the floater assembly is disposed inwardly of
the outer periphery of a lower die of the set. As
one skilled in this art will appreciate after
reading this description, placement of the floater
is dictated by the location of the areas to be first
formed and locked. In the case of a welded blank,
the welded seams of the blank are to be formed and
locked first. The floater assembly is mounted to a
positioning assembly so as to be movable relative to
the dies of the first set. In a first embodiment of
the present invention, the positioning assembly is
actuated or powered by a die cushion incorporated as
a part of the press.
More particularly, in the first embodiment in
accordance with the principles of the invention, a
first die having a die surface is provided and
2 1 64999
spaced from a second die having a die surface
opposed to the first die surface. Disposed inside
of the second die and slidable relative to the
second die is a floater assembly that also has die
surface(s) opposed to the first die surface. Again,
the dies surface(s) of the floater assembly are
positioned so that they will correspond to, for
example, the welded areas of the blank. Thus, the
floater assembly is opposed to a portion of the
first die, and the second die is opposed to the
remainder of the die surface of the first die.
Prior to commencement of the forming process,
the floater assembly is biased by the die cushion
assembly, which is of known type, so that its die
surface is ahead of that of the cavity of the second
die. A blank is placed in the apparatus so that a
first portion thereof, such as a portion of a welded
seam, overlies a die surface of the floater
assembly. Once the blank is so positioned, upper
binders disposed peripherally of the first die and
opposed to the periphery of the second die are
displaced towards the second die to clamp and hold
the blank in position. The first die is then moved
towards and into contact with the floater assembly
by conventional means. During this period, the
cushion assembly biases the floater assembly against
the first die with sufficient force to effect
formation of the blank therebetween, thereby both
forming and locking the first portion of the blank
between the first die and the floater assembly.
This biasing force, however, is insufficient to
prevent the forward progress of the first die.
Thus, continued movement of the first die pushes the
blank and displaces the floater assembly relative to
2 1 64999
the second die. During this displacement, the first
portion of the welded blank remains locked between
the first die and the floater assembly. By the end
of the stroke of the first die, the remaining
portion(s) of the blank are formed between the first
die and the second die.
In accordance with a second embodiment of the
invention the floater assembly is disposed inwardly
of the outer periphery of an upper die of the press.
As in the first embodiment, the floater assembly is
mounted to a positioning assembly for movement
relative to the upper and lower dies. In this
embodiment, the positioning assembly incorporates a
pneumatic or hydraulic system to bias the floater
assembly to position the die surface of the floater
assembly ahead of the cavity of the upper die. When
the upper die and floater assembly are displaced
towards the lower die, the first portion of the
blank is formed and locked between the floater
assembly and the lower die. Continued engagement of
the floater assembly against the lower die displaces
the floater assembly relative to the upper die and
permits formation of the remaining portion(s) of the
blank between the upper die and the lower die.
Other objects, features, and characteristics
of the present invention as well as the methods of
use of related elements will become more apparent
upon consideration of the following description and
the appended claims with reference to the
accompanying drawings, wherein like reference
numbers designate corresponding elements in the
various figures.
2 t 64999
__ 6
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic sectional view of a
stretch controlled forming apparatus provided in
accordance with a first embodiment of the present
invention;
FIGURE 2 is a schematic sectional view of the
apparatus of FIGURE 1 showing the binder clamping a
blank in position between the binder and the
periphery of the second die;
FIGURE 3 is a schematic sectional view of the
apparatus of FIGURE 1 showing the first die
displaced into engagement with the floater assembly;
FIGURE 4 is a schematic sectional view of the
apparatus of FIGURE 1 showing the first die
displaced into engagement with the remainder of the
second die;
FIGURE 5 is a schematic sectional view of the
apparatus of FIGURE 1 showing the first die
retracted after formation;
FIGURE 6 is a schematic sectional view of the
apparatus of FIGURE 1 showing the binder dies
retracted after formation and the floater assembly
in its elevated position; and
FIGURE 7 is a plan view of the lower die
assembly in accordance with the invention;
FIGURE 8 is a schematic sectional view taken
along line 8-8 of FIGURE 7; and
FIGURE 9 is a schematic sectional view of a
stretch controlled forming apparatus provided in
accordance with a second embodiment of the present
invention.
7 2 1 64999
DETAILED DESCRIPTION OF THE PRESENTLY
PREFERRED EXEMPLARY EMBODIMENTS
In FIGURE 1, a first embodiment of a stretch-
controlled forming mechanism in accordance with the
invention, and with which the method of the
invention can be carried out, is designated
generally by the reference number 10. At a minimum,
the mechanism of this and other embodiments of the
present invention includes three blank forming die
components, one of which is opposed to the other
two, which are disposed adjacent one another. As
one skilled in the art will recognize after
reviewing the following detailed description, any
number of die components greater than three may be
used. Additionally, for the sake of convenience
only, the dies will be referred to by the
designations first, second, etc. and one of the die
components, which could be characterized as a third
die, will be referred to as a floater assembly
because of the manner in which it is preferably,
although not necessarily, mounted. Further, for
convenience, the upper die will be referred to as
the first die. The apparatus and method of the
present invention, however, are not limited to the
particular die orientations or labels used herein,
as will become apparent from the detailed
description provided herein below. Thus, for
example, the first die could be either the upper die
or the lower die and the floater assembly could be
disposed adjacent to or inside of either the upper
die or the lower die. As will become clear
following review of this detailed description,
placement of the floater assembly is dictated by the
21 64999
.. 8
relative location of the welded areas of the blank
to be formed.
As shown in FIGURE 1, the molding apparatus
embodying the principles of the present invention
includes a first die which in the first illustrated
embodiment is in the form of an upper punch 12
selectively driven towards or retracted from a
workpiece, for example comprising a welded blank 14,
by a press inner ram 16 which may be of conventional
construction. The first die 12 has a die surface 18
that, upon operative engagement, imparts a desired
shape to the welded blank 14. An upper binder 20,
which is conventionally considered as a portion of
the first die 12, is mounted in surrounding relation
to the first die 12 and is selectively driven
towards or retracted from the workpiece 14 by a
press outer ram 22, again of conventional
construction, to hold the workpiece 14 during
forming. Presses of this configuration commonly are
called double action presses. As one of ordinary
skill in this art will recognize, particularly
following review of the description of the second
embodiment, the present invention is not limited in
application to double action presses.
The molding assembly 10 further comprises a
lower die assembly 24 which in the first illustrated
embodiment includes the second die 26. As best seen
by reference to FIGURES 1, 7, and 8, the second die
26 defines roughly a U-shaped space 25 in which
other assemblies, as described below, are disposed.
The second die 26 is provided in opposed, facing
relation to the first die 12, and upper binder 20.
The second die 26 has a die surface 30 that in
conjunction with the first die surface 18 imparts a
2 1 64999
~ g
particular shape and configuration to a portion of
the welded blank 14.
As shown in FIGURE 1, the first
embodiment of the present invention includes a fixed
second die 26 having the U-shaped space 25 and a
first die 12 that can be selectively displaced
toward and away from the second die. The present
invention, of course, only requires relative
movement between the first and second dies. Thus,
either or both of the dies may be movable.
In accordance with the invention, a floater
assembly 32 is positioned to correspond to the
locations of welded seams 34 of the blank to be
formed. In the first exemplary embodiment
15 illustrated in FIGURES 1-8, the floater assembly 32
is defined inside of the second die 26 so as to
correspond to the location(s) of welded seams 34 in
the welded blank 14. The floater assembly 32. may be
in the form of a single die component 36 mounted
inside of the second die. Alternatively, the
floater assembly 32 may be comprised of a plurality
of die components 36 suitably disposed about the
periphery or inside of the second die as deemed
appropriate or necessary to correspond to the
25 location of the welded seams 34 of the welded blank
14 to be formed in the molding apparatus 10. While
such variations will be apparent to one skilled in
this art upon review of this disclosure, the first
illustrated embodiment contemplates a floater
30 assembly comprising floater die components 36
disposed inside of a second die and the description
hereinbelow will be directed to that embodiment.
The floater assembly 32 comprises at least
one die component 36, as noted above, hereinafter
2 1 64999
referred to in the singular as a floater component
36. In the first illustrated embodiment, the die
component 36 is mounted slidably in a vertical
portion of the U-shaped space 25 defined by the
second die 26. It is also to be noted that in this
embodiment, the blank engaging face of the floater
component has a step 37 defined on the die surface
thereof to lock both the light and heavy gauge
sheets of the blank in a secured position during
subsequent forming.
The floater assembly 32 further comprises a
positioning assembly 38 for supporting the floater
component 36 relative to the second die 26. In the
first illustrated embodiment, the positioning
assembly 38 includes a support plate 40 having a
first side 42 and a second side 44. The first side
42 of the plate 40 is in supporting relation to the
floater component 36. The second side 44 of the
plate 40 is supported relative to the second die 26
and the press base by cushion pins 46. Stop blocks
43 are mounted to the first side 42, and bottoming
blocks 45 are mounted to the second side 44. Those
blocks are sized, as described more fully
hereinbelow, to appropriately define the stroke of
the positioning assembly 38. In the first
illustrated embodiment, a single plate 40 supports
the floater component 36 of the floater assembly 32.
It is to be appreciated, however, that separate
plates 40 may be provided for each floater component
36 of the floater assembly 32 where more than one
component 36 is provided. However, to ensure
simultaneous and uniform displacement of the floater
component 36 of the floater assembly 32 the
provision of a single continuous plate structure is
2 1 649q9
currently envisioned to be most desirable. The U-
shaped space 25 accommodates such a common plate.
The cushion pins 46 may be steel rods
approximately 1.5 inches in diameter that extend
through pin holes in the base of the press and
transmit force from the die cushion assembly (not
shown) to the floater plate and hence to the floater
component 36. Die cushion assemblies are
conventional mechanisms provided to supply power to
presses so equipped. For example, cushion
assemblies are used to lift, through pins, a
workpiece from a die cavity following formation.
In the first illustrated embodiment, the
cushion pins 46 are provided through pin holes such
that sufficient support is provided for and force is
applied to the floater component 36. For example,
the pins may be disposed every six inches over the
area of the plate 40. Generally, the floater
component 36 is biased continually by the cushion
assembly subject to lockout, as described more fully
hereinbelow.
The force with which the floater component is
biased and the displacement of the floater assembly
relative to the cavity of the second die, i.e. the
stroke of the floater component 36 depends on that
deemed necessary or desirable to form the blank at
the weld seam and to lock it during subsequent
forming, the characteristics of the weld blank, the
part being formed, etc. It is anticipated that
optimum displacement and force values will be best
determined by try-out.
As noted above, specific values for the
aforementioned parameters are dictated necessarily,
of course, by the design considerations presented by
21 64999
12'
particular applications, and therefore, no preferred
values are suggested. Orders of magnitude for those
parameters observed by the inventor during
experimentation, however, likely will prove typical.
5 In one case, satisfactory results were achieved when
the inner ram 16 was a 500 ton press, the outer ram
22 was an 80 ton press, the bias force of the
cushion assembly was set at 19 tons, and the cushion
travel was limited to 1 3/4 inches. In another
case, satisfactory results were achieved when the
inner ram 16 was a 1, 200 ton press, the outer ram 22 .
was an 90 ton press, the bias force of the cushion
assembly was set at 25 tons, and the cushion travel
was limited to
15 60 mm.
A mechanism other than a conventional die
cushion for biasing the floater component 36 may be
provided in addition or in the alternative where
appropriate, as will be readily evident upon review
20 of the description of the second embodiment,
including hydraulic pistons operatively engaged in
- hydraulic cylinders, pneumatic cylinders, and
other known resilient/biasing support structures.
Wear plates 48 are suitably disposed
25 intermediate the floater assembly 32 and each side
of the vertical portion of the U-shaped space 25 of
the second die 26. The wear plate(s) 48 ensure
there will be smooth, low friction, axial sliding
movement of the floater assembly 32 relative to the
structures adjacent thereto without undue component
wear.
While in the illustrated embodiment the
floater assembly 32 is provided so as to be
selectively displaced relative to the second die 26,
21 64q99
13
it is to be understood that depending upon the shape
to be imparted to the welded blank 14, and other
considerations, it may be deemed advantageous or
desirable to provide an assembly in which the so
called floater assembly is in fact fixed and the
second die is mounted for selective displacement
towards the first die to impart the desired shape to
the metal blank following engagement of the welded
seams by the floater assembly and first die. Thus,
while the first illustrated embodiment contemplates
a fixed second die and a shiftable floater assembly
the invention is not deemed to be limited to that
particular configuration.
In use, a welded blank 14 is positioned
on the top of the lower die assembly 24 while the
first die 12 and upper binder 20 are disposed in
their elevated positions (FIGURE 1). The welded
blank 14 is secured in position by the upper binder
20 once it reaches the end of its descending stroke
and clamps the welded blank 14 between the upper
binder 20 and the periphery of the second die 26
(FIGURE 2). Once clamped and in a conventional
manner, the binder 20 prevents gross movement of the
workpiece yet allows blank material to flow inwardly
during formation.
The first die 12 is then displaced towards
the second die 26 and the floater assembly 32. As
the first die 12 contacts the welded blank 14 and
displaces it relative to mated surfaces of the upper
binder 20 and the second die 26, the first die 12
pushes the blank down onto the top surface of the
floating component 36 of the floater assembly 32.
This engagement forms or imparts a desired shape to
the welded seam portions of the blank 14 and
21 64999
14
securely locks the welded seams 34 between the first
die 12 and the floater component 36 (FIGURE 3). As
noted above, the step 37 assists in locking the
welded blank in a secured position during subsequent
forming.
To properly form and lock the welded portion
of the welded blank, the biasing force and stroke of
the cushion assembly must be selected appropriately
in light of expected forming loads and final
dimensions of the finished product. At a minimum,
the cushion assembly must bias the floater component
36 with a force sufficient to deform the blank yet
sufficiently less than that of the first die press
that the floater component 36 will be displaced
against its bias in response to continued movement
of the first die 12. Further, the selected biasing
force must be sufficient to lock the welded portion
of the welded blank to isolate stretch and formation
of the heavier gauge material from stretch and
formation of the lighter gauge material.
Following forming and locking of the welded
portion of the welded blank 14, continued downward
motion of the first die 12 displaces the floater
assembly 32 downwardly relative to the second die 26
and allows the die surface 18 of the first die 12
and the die surface 30 of the second die 26 to form
the remainder of the blank (FIGURE 4). Thus, at the
end of the descending stroke of the first die 12,
forming of the blank 14 has been substantially
completed. secause the welded seam(s) 34 were
clamped and locked between the first die 12 and the
floater assembly 32 in advance of format-ion of the
remainder of the blank, no cracks or splits are
21 6499~/
_ 15
generated in the thinner sheet material near the
joint.
As is apparent, and as was noted above,
although in the illustrated embodiment the second
die was fixed throughout the stroke of the first
die, the second die could be mounted for movement
relative to the first die if necessary or
appropriate to the formation of the blank.
Following blank formation, the first die 12
is retracted to its elevated position. Thereafter,
the upper binder 20 is retracted to its elevated
position. However, the floater assembly 32 remains
at its bottom dead center or lower limit of its
stroke until the first die 12 and the upper binder
20 are completely cleared from the molded blank 14'
and are in their elevated positions (FIGURE 5). The
floater assembly is maintained at the lower limit of
its stroke by locking out the die cushion in a known
manner so that no power or biasing force is
transmitted to floater assembly 32. The biasing
action of the cushion assembly is reengaged
following a time delay to allow sufficient time for
the upper binder 20 and the first die 12 to retract,
to avoid distortion of the formed blank.
After the upper binder 20 is retracted to its
elevated position and the time delay expires, the
cushion assembly is engaged, and the floater
assembly 32 is elevated to lift the formed part 14'
off of the lower die 26. The formed part may then
be removed and otherwise further processed ~FIGURE
6).
As noted above, some presses are not equipped
with die cushion assemblies. In such apparatus or
when use of the die cushion is impractical or
21 64999
16
undesirable, a hydraulic or pneumatic system may be
provided to bias the floater assembly. Such an
alternative system is schematically illustrated in
the embodiment of FIGURE 9, which is described
herein below.
In the second embodiment, a floater assembly
in accordance with the invention is incorporated in
a single action press. As noted above, however, the
present invention is not limited to a particular
configuration, and the press configurations shown
are intended to illustrate the flexibility of the
present invention rather than suggest any
limitation.
In the second illustrated embodiment, the
first die 112 is provided now as a lower fixed die,
and the die assembly 124 is disposed above the first
die 112. Die assembly 124 is selectively driven
towards or retracted from the workpiece 114 by the
press ram 116. Again, the press ram 116 is of
conventional design.
The first die 112 is fixed to a press bed and
includes the die surface 118 that imparts a desired
shape to the welded blank 114. A blank holder 150
is mounted in surrounding relation to the first die
112 and serves the same function as a binder.
Specifically, biasing cylinders 152, for example
nitro cylinders, disposed below the blank holder 150
push the facing surface of the holder above the die
surface 118 and provide sufficient force to clamp
the blank 114 during forming. In a known manner,
the blank holder 150 prevents gross movement of the
blank during forming while still allowing inward
material flow.
2 1 64999
17 '
The die assembly 124 comprises in part the
second die 126 including the U-shaped space in which
the positioning assembly of the second embodiment is
disposed. The second die 126 is provided in
5 opposed, facing relation to the first die 112 and
the blank holder 150. The second die includes the
die surface 130 that in conjunction with the first
die surface 118 imparts a particular shape and
configuration to a portion of the welded blank 114.
The floater assembly 132 is defined inside of
the second die 126 and is positioned to correspond
to the locations of the welded seams 134 of the
blank to be formed. As was noted above with respect
to the first embodiment, and remains true in this
15 exemplary embodiment, the floater assembly 132 may
include a single die component 136 or a plurality of
such die components disposed about the periphery or
inside of the second die as deemed necessary by the
position of the welded seams 134. As with the first
20 embodiment, the blank engaging face of the floater
component 136 preferably includes a step 137 to
positively lock the welded portion of the blank 114
in a secured position during subsequent forming.
The floater assembly 132 further comprises a
25 positioning assembly 154 incorporating many of the
components of the positioning assembly 38 of the
first illustrated embodiment. The positioning
assembly 154 of the second embodiment includes the
plate 140 having a first side 142 and a second side
144. The first side 142 is in engaging relation to
the floater component 136. The second side 144 is
in engaging relation to a drive assembly 156,
described more fully hereinbelow. Stop blocks 143
and bottoming blocks 145 are mounted to the plate
18 2 ~ 64999
140. Those blocks are sized and serve the same
function as those indicated in the description of
the first illustrated embodiment. Again, it is to
be appreciated that separate plates may be provided
5 for each floater component 136.
In the second illustrated embodiment, the
drive assembly 156 serves a function similar to that
of the cushion assembly. The drive assembly 156
includes an adapter plate 158 disposed between the
press ram 116 and the second die 126. A plurality
of drive devices 160 housed within the adapter plate
158 are engaged operatively to the plate 140.
Suitable drive devices 160 may be, for example,
hydraulic or pneumatic cylinder and piston
15 assemblies. For this illustrated embodiment, the
drive devices are pneumatic cylinders.
Notwithstanding the illustrated structure, the
particular drive devices provided in accordance with
the second embodiment of the invention depend upon
20 the desired displacement of the floater component
136 during the descending stroke of the die assembly
124 and the necessary load to lock and form the
welded portion of the blank 114.
The drive assembly 156 further includes
25 supply lines, exhaust lines, and a storage tank (not
shown in detail). The drive assembly 156
continually biases the floater component 136 subject
to lockout. During formation, the pneumatic
cylinders are pressurized to push the floater
30 component 136 towards its extended position with
sufficient force to form and lock the welded portion
of the welded blank. When required, as described
below, the pneumatic cylinders can be selectively
deactivated by exhausting to tank.
2 1 64999
19
The second illustrated embodiment is used to
form the welded blank in a manner generally similar
to the first embodiment. A welded blank 114 is
positioned on the elevated surface of the blank
holder 150 while the die assembly 124 is in its
elevated position. Thereafter, the press ram 116
pushes the die assembly 124 towards the welded blank
114. Because the blank holder 150 is elevated
slightly relative to the first die 112, a peripheral
portion of the second die 126 clamps the blank 114
against the blank holder 150 prior to any other
contact between the dies and the blank. The blank
holder 150 retracts under the force of the second
die 126, and the biasing force of the nitro
15 cylinders 152 prevents gross movement of the blank
114 during subsequent forming. At this stage, the
blank 114 contacts the die surface 118 of the first
die 112.
Continued downward motion of the die assembly
124 displaces the blank holder 150 and brings the
floater component 136 into contact with the welded
portion of the welded blank 114. This engagement
forms the welded portion of the blank 114 and
securely locks that portion between the floater
component 136 and the first die 112. The discussion
of required forces and displacements in regard to
the first illustrated embodiment is generally
applicable here, and therefore, is not repeated.
Following forming and locking of the welded
30 portion of the welded blank 114, continued downward
motion of the die assembly 124 displaces the floater
component 136 against the biasing action of the
pneumatic cylinders and allows the die surface 130
of the second die 126 and the die surface 118 of the
2 1 64999
first die 112 to form the remainder of the blank.
Again, because the welded seam 134 was locked
between the first die 112 and the floater component
136 prior to formation of the remainder of the
blank, no wrinkling or splitting occurs.
Following formation, the pneumatic cylinders
are exhausted to tank thereby unloading the biasing
force of the drive devices 160. Thereafter, the die
assembly 124 is retracted to its elevated position
and moves relative to the floater assembly 132. The
floater assembly 132 moves relative to the second
- die 126 under its weight and gently pushes the
formed workpiece 114' away from the die cavity.
It should be noted that the embodiment of
FIGURE 9 is seen to be particularly advantageous
when forming, for example, an automotive body panel,
such as a door, because the formed part does not
need to be turned over in advance of further
processing, as would be the case with a press of the
type shown in FIGURE 1.
Indeed, as is apparent from the foregoing,
the floater assembly of the invention can
advantageously be incorporated either in the upper
or lower die structure of a press. This flexibility
permits the advantages of the invention to be
realized in a variety of part forming systems.
As is also apparent from the foregoing, the
apparatus and method of the invention may be used to
' form metal blanks or workpieces of steel, aluminum,
or any other known metal or metal alloy, or
combination of metals or metal alloys. Moreover,
the apparatus and method diclosed herein, while
particularly advantageously used to form blanks
having portions of differing gauges, may be used to
2 1 64999
21
form blanks of a single guage and/or workpieces
which have been previously formed at least in part.
Thus, while the invention has been described
in connection with the preferred embodiments, it
should be understood readily that the present
invention is not limited to the disclosed
embodiments. Rather, the present invention is
intended to cover various equivalent arrangements
and methods included within the scope of the
appended claims.
