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Патент USA US2857669

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Oct. 28,. 1958
Filed Dec. 1, 1955
' FIG‘. 6
United, States Patent 0
details of the panel, such as theone expanded in the dies
of Figs. 4-6, these views showing how the cross sectional
shape of the passageway changes or develops as the
Paul R. Staples, Louisville, Ky., assignor to Reynolds
Metals Company, Louisville, Ky., a corporation of
Patented Oct.28, .1958
Application December 1, 1955, Serial No. 550,389
4 Claims. (Cl. 29-1573)
expansion operation proceeds; and
Figs. 10 and 11 show a panel at the beginning and the
end respectively of the expansion operation when con
ducted in hydraulically loaded dies.
In carrying out the invention, two foreshortened metal
sheets, with a foreshortened stop weld pattern of appro
10 priate design interposed between them, are roll bonded
to form a relatively elongate unexpanded panel 1 having
unbonded passageway forming portions 2. If this panel
be conventionally expanded to form passageways 3, it is
very apt to neck down as indicated at 4 in Fig. 3. Con‘
This invention relates to "pressure welded passageway 15 sequently, in the absence of corrective measures which
panels for evaporators and the like. >
In expanding the unbonded portions of these panels,
prevent neck down, it becomes necessary to form the
panel from metal sheets having a thickness large enough
to insure an adequate ?nal thickness in the neck down
there is a marked tendency for the metal, which forms
the walls of the expanded passageways, to “neck down”
area. This is objectionable since it necessitates a sub
along the marginal edges of the. passageways, which is to 20 stantial increase in the amount of metal contained in a
say, closely adjacent the joint ‘between the bonded and
given panel over what could be used in the panel in the
unbonded portions of the panels. For example, an ex
absence of neck down, and a corresponding increase in
panded wall thickness, which should be of an order of,
the cost of the panel without improving the panel in any
say 0.030 to 0.032 inch, often necks down as much as .
.005 to .007 inch so that, in the neck down area, the 25
overall ‘thickness may range from .023. to .027 inch.
Consequently, in the absence of proper corrective meas—
Inv accordance with the present- invention, neck down
is substantially minimized if not eliminated by clamping
the panel between yieldable dies or platens and then ex
ures, it becomes necessary to increase the thickness of the
panding the panel against the yieldable resistance of the
normal starting sheet metal to a degree sufficient to
dies. Accordingly the panel 1 is placed between movable
insure a safe ?nal thickness in the neck down areas. 30 dies 5 and 7 which are initially spaced apart a distance
This is objectionable since it necessitates a very substan
su?icient to receive the panel between them. Thereupon
tial increase in the amount of metal contained in a
the lower die 5 is hydraulically raised by hydraulic jack
given panel.
6 until the panel is clamped between the lower die 5
The principal objects of the present invention are: sub
and the upper die 7. Preferably the elevated position
stantially to reduce, if not to eliminate, the tendency to 35 to which the lower die is moved, is such that the springs
neck down; and to strengthen the walls of the passage
8 of the upper die are compressed sufficiently to exert
ways throughout their extent and thereby additionally
a predetermined clamping pressure upon the panel, this
decrease the likelihood of accidental rupture.
clamping pressure being on the order of, say, 200 p. s. i.
All of the more important objects of my invention can
to 1,000 p. s. i. The hydraulic jack 6 now functions to
be achieved by expanding the panel outwardly against 40 hold the lower die 5 in that elevated position.
yieldable pressure-loaded dies or platens preferably from
The expansion apparatus 9 is now operated to force
a point approximating zero expansion to a point of de
hydraulic liquid under pressure into the panel and along
sired expansion which may be ?nal expansion or slightly
the unbonded portions thereof. As the expansion pres
in excess of ?nal expansion. In other words, a ?at panel
sure increases the liquid ?ows throughout the panel
is positioned between two dies which preferably engage 45 and begins to force the upper die 7 upwardly against
both faces of the ?at panel from the very beginning to
the yieldable resistance of the springs 8. Where the
the end of the expansion operation and which are made
panel is clamped at the beginning of the operation, with
to resist the expansion in a yieldable manner. I have
a force of 1,000 p. s. i., it will be necessary to apply
found that this minimizes and quite often prevents neck
the hydraulic liquid at a pressure greater than 1,000
down. Furthermore, it effects a working and correspond 50 P. S. I. before it will enter the panel and begin to expand
the panel.
ing strengthening of the passageway-forming metal, along
the marginal edges of the passageways where the un
The maximum pressure used in the expansion opera
bonded portions join the bonded portions of the panel.
tion will depend in a large measure upon the composition
This does not occur in a case where dies are spaced
of the metal forming the panel. Normally with alumi
to require substantial expansion before effective die en 55 num panels of conventional composition, a ?nal expan
The invention is illustrated in the accompanying draw
ing wherein:
sion pressure of 3,000 to 4,000 p. s. i. will be suf?cient.
Therefore, as the expansion proceeds from minimum
to maximum, the expanded passageways will change their
Figure l is a partly broken plan view of a conven
contour as indicated in Figs. 7 through 9. Here it will
tional pressure welded unexpanded passageway panel;
60 be noted that the ?at crest 11 of the passageways is rela
Figure 2 is a section taken along line II—II of Fig
tively wide in Fig. 7 but, as the expansion height be
ure 1;
comes progressively larger, the crest width becomes pro
Figure 3 is an enlarged fragmentary sectional detail
gressively smaller as indicated in Figs. 8 and 9. Fur
of a conventionally expanded panel illustrating the neck
thermore, the metal 12, between the crest 11 and the
down condition which is corrected by the present inven 65 body of the panel 1, will be worked during the expan
Figure 4 shows a panel between spring loaded dies
which are in the panel receiving position;
Figures 5 and 6 show the panel of Fig. 4 at the be
ginning and the end respectively of the expansion opera 70
tion as conducted in the spring loaded dies of Fig. 4;
Figs. 7, 8 and 9 are enlarged fragmentary sectional
sion and thereby strengthened. Consequently, neck down
is not only avoided but the metal, where neck down
has heretofore occurred, being worked during expan
sion, will be much stronger; hence able to withstand
higher internal pressures in a safe manner.
The upper die 7 of Figs. 4»—6 is designed to move up
wardly until, when the panel is fully expanded, a stop
position is reached. If desired, this position. may be de
termined by designing‘ the‘ springs to exert a clamping
force equal to the expansion force when the panel is'
fully expanded.
Preferably, however, the springs 8
should be somewhat weaker‘ with the dies arranged to
move‘ upwardly- against the‘ sprin‘g'loa'd until‘ they strike
cated. between. bonded“ portions, comprising-z clamping
the panel between relatively yieldably-mounted rigid
platens having" ?ush" face-to-face engagement with said
unbonded portions; and expanding unbonded portions
outwardly against the resistance of said platens to move
the platens relatively apart, to ?atten unbonded portions
engaging said platens, to work the panel metal which ex
the gauge blocks 14‘ which‘ determine the‘ ?nal position.
tends across the space be‘t'ween the platens and the
The’ die‘ apparatus shown‘ in‘ Figs.‘ 10 and 11 com:
bonded portions. ofjthe panel'and‘to form said unbonded
prises: an upper stationary die 16; and‘ a‘ lower’ movable
die 17, the‘ latter‘ being‘ supported‘ and moved by a hy 10 portions into a passageway having substantially the ex
pansion height desired in the ?nal panel.
draulic jack 18‘. With this‘ arrangement, the jack is
2. The‘ method" of: claim. 1. including: expanding the
operated to open the dies to‘receive the panel and to
close the dies- to clamp’the'panel with a~ force not less
panel against spring loaded“ platens.
3. The method of claim 1 including: clamping the
than that‘create'dl by the" maximum‘?nal expansion pres
sure of, say 3,000 p: s. i. Now“ the expansion ?uid‘ is 15 panel.“ with. an; elevated pressure'of predetermined magni
fed to the panel‘at-a-pressure-of13;000' p. s. i. Naturally
4. The method' of' claiin 1' including: clamping the
this ?uid cannot enterthel panel‘ and‘ expand it unless
panel between ?uid actuated platens which are held in
the clamping pressure is released} Accordingly, the
position by a ?uid at an elevated pressure; feeding an
lower die 17 is‘permitted‘to~move»slowly‘downward, to~
expansion‘ ?uid: to" the panel at. an elevated pressure; and
ward and to a’positioncorrespondingto full expansion,
by releasing: the- liquid pressure of the hydraulic jack
progressively releasingjth'e platen holding pressure to al
18. through a suitable valve‘ 19;‘ As the-pressure of the
jack 18 decreases, liquid will enter the panel and ex
respondingly‘ expand the panel.
pand it contemporaneously and correspondingly. When
the fully expanded position is reached, the expansion
low‘the expansion fluid‘ to separate the platens and cor
References Cited‘ inither ?le of this patent
pressure is released and the dies opened‘ to permit re
moval of the‘expanded panel.
Having‘ described my invention, I claim:
Benedict ___________ _- Apr. 30,1935
Evans ______________ _.. Oct. 14, 1941
way panel composed‘ of a pair of superposed metal sheets. 30' 2,649,067
Kranenb'erg _________ __ Aug. 18, 1953
Long ______________ .._ Dec. 15, 1953
1. A method of expanding a pressure welded passage‘
containing unbonded potential passageway portions 10
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