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Патент USA US3051225

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Àug- 28, 1962
F. w. scHNAcKENBx-:RG
Filed Aug. 2, 1960
2 Sheets-Sheet 1
Aug. 28, 1962
F. w. scHNAcKr-:NBERG
Filed Aug. 2. 1960
2 Sheets-Sheet 2
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United States Patent
Patented Aug. 28,1962
the like which is of substantially large dimensions yet
Fred W. Schnackenberg, St. Louis, Mo., assignor to N_ord
berg Manufacturing Co., a corporation of Wisconsin
Filed Aug. 2, 1%0, Ser. No. 47,165
9 Claims. (Cl. 153-32)
This invention relates in general to thermal oven flat
tening plates and more particularly to plates used in flat
tening rolled sheets of magnesium or the like during heat
treatment. It further relates to a method of making ther
mal oven flattening plates.
Flattening plates are used in the production of sheet
magnesium and metals of a similar nature. During heat
treatment, to which the sheet metal is subjected after un
which has a relatively low weight-to-surface area ratio.
Another object is to provide a flattening plate which
permits free circulation of the heat treating atmosphere
within its contines.
Yet another object is to provide a flatening plate hav
ing lifting lugs which equalize stresses developed during
plate handling operations.
Another object is toprovide a flattening plate of 'sub
stantial surface area comprising parallel thin’walls inter
connected by generally vertically disposed, transversely
extending webbing.
These and other objects of this invention will be found
in the following specification and claims wherein like
reference numerals identify like parts throughout.
dergoing rolling operations or the like, the ñattening plates
The invention is illustrated more or less diagrammati
are used to provide a level and smoothly ñnished ilattening
surface for the large sheets.
A continuing problem in the use of such thermal ñat
cally in the drawings wherein several embodiments are
FIGURE l is a view in perspective of a flattening plate
tening plates is that of maintaining a high degree of flat 20 embodying this invention,
FIGURE Z is an enlarged partial side elevation of the
ness and a tine iinish during the service life of the plates.
flattening plate of FIGURE l,
The extreme ñatness is required to insure the ñatness of
the iinished sheets of metal. The finish or smoothness of
the surface is important since it, in turn, effects the surface
ñnish of the sheet being heat treated.
A number of factors operate to adversely affect the flat
ness of the plates and the surface finish. The weight of
each plate, for example, is one of its own Worse enemies.
It will be understood that these plates, being of substantial
size, are normally extremely heavy. In stacking the plates
with the magnesium sheets, for example, precedent to heat
treatment, they are normally moved by attaching cables
FIGURE 3 is a view taken along line 3_3 of FIG
URE 2,
FIGURE 4 is an enlarged side elevation of a portion of
a flattening plate showing another embodiment of this
invention, and
FIGURE 5 is an enlarged partial side elevational of
still another embodiment of this invention.
A thermal ilattening plate embodying this invention is
indicated generally at 2 in FIGURE l. The plate is com
prised of cast metal which might be Meehanite or nodular
iron or the like. Grade HD Meehanite, of the type de
from overhead lifts to attachments onthe plates. As the
veloped by the Meehanite Metal Corporation, Chattanoga,
plates are lifted, their extreme weight causes considerable
bending stresses to develop. These, of course, are a 35 Tennessee, has been found to be ideally suited for these
plates; however, other ferrous alloys might be utilized.
hazard to plate liatness. The hazard is even more pro
Plates of various size are used in practice. ’ 'I'hey are all
nounced when the plates are handled after the heat treat
relatively large, however. Dimensions of ‘4l/2> feet x l13
ing cycle is performed. In such case, the plates are still
at considerably elevated temperatures and, consequently, 40 feet x 61/2 inches are common and the plate'shown might
be of these dimensions.
bend more easily.
A plate is ñrst cast inthe general shape seen in FIG
During the heat treating cycle the plates are subjected
URE 1 with passagewaysß and 4 of similar but inverse
to extreme temperature ranges such that high thermal
cross section extending therethrough. The function of the
stresses are developed. For example, it -is accepted prac
tice to heat treat magnesium sheet for a period up to 24 45 passageways is somewhat self-explanatory; however, their
importance will be emphasized further in the succeeding
hours at 900 degrees F. The sheets and consequently the
discussion of the invention. The passageways 3 and 4 are
plates are then removed from the furnace While still at a
by oppositely inclined webs 5 and 6l along the
temperature of in the neighborhood of 200 to 50() degrees
length of the plate. Upper and lower walls 7 and 8 ex
F. In continuous use, the heating and relativelv rapid
tend the length and width of the plate and provide flat up
cooling cycles tend to cause the plates to warp slightly. 50 per and lower surfaces 9 and 10. The walls 7 and 8‘ are
In addition, the linish of the plate surfaces is adversely
machined after casting to provide these overall ilat sur
affected to some degree by any bending or warping.
faces and put a ñne ñnish onthem. It is’commonly-spee
Accordingly, a primary object of this invention is to
iûed that the surfaces mustnot vary in flatness more than
provide a thermal oven flattening plate which is capable
.-005 inch in 13 feet from end to end and have a number
of withstanding substantial thermal stress'while maintain 55 125 micro finish.
ing a prescribed flat surface.
Another object is to provide a flattening plate which is
' In FIGURES l and 2, the passageways are shown hav
ing a iirst configuration with distinctive lifting lugs 12 and
13 disposed on opposed Vwebs 5 and 6; respectively,»adjacomparatively light in weight and is consequently less
cent opposite ends of the flattening lplate. As will be seen
subject to bending caused by plate handling operations.
in FIGURE 3, lthe lugs have upperv and lower lips A‘1li
Yet another object is to provide a flattening plate which v
and 15 thereon forreceiving and holding pear-shaped lift
has a prescribed fine finish `and maintains this finish
throughout the service life of the plate.
ing _rings of conventional construction.>
Still another Objectis to provide> a flattening plate cast
` FIGURE 4 shows» a modification of the web construc
of a ferrous alloy such as nodular iron or Meehanite or
tion of the ñattening plate in which passageways 18: and
; 3,051,215
. 19 of similar but inverse cross section, are separated by
extending passageways throughout the length of the plate,
irregularly shaped webs 20 and 2'1 having opposed inclina
tions. VAs dictated by the shape of the webs Zttand 21,
the weight can be decreased to an acceptable figure. It
has been found, for'example, that the Weight can bere
duced to approximately 150 pounds per square Afoot of
plate surface by the use of these passageways.
The webs remaining between the passageways, how
it will be seen that lifting lugs 22 of this modification are
of an inclined S-shaped configuration.
FIGURE 5 shows yet another modification of the flat
tening plate. In this modification the lifting lugs (not
shown) are not cast integrally with the flattening plate.
ever, are strategicallyplaced to support the upper and
lower walls of the plate and insure the retention of the
' prescribed ñatness and ñnish'throughout the service life
' The passageways 25 and 26 are of a configuration general
ly similar to that shown in the embodiment in FIGURES lO of the plates. The plates thus have the lightness of a
substantially hollow structure while retaining the rigidity
1_3. In this embodiment, however, modified passageways
that a solid plate might have. Consequently, in the lifting
27 having arcuate shaft seats 2S and 29 extending there
>and handling operation wherein carrying rings slip over
through are provided adjacent the opposite ends of each
the lifting lugs to alford lifting attachments for an over
plate to receive a shaft carrying lifting lugs (notrshown).
head lift, the plates do not bend to a degree exceeding
It has been found that integrally cast lugs are best suited
their tolerances.
to most operations and provide optimum performance;
It will thus be seen that a new and improved thermal
however, under certain circumstances the lug carrying
ñattening plate has been shown and described. In addi
shafts might be utilized.
tion, a new method of manufacturing thermal flattening
. A unique method is employed in manufacturing these
plates such that highly desirable characteristics are im 20 plates has been described.
The thermal oven flattening plate which embodies this
parted to the plates.
invention has a relatively low weight-to-surface area
' A'plate is first cast from Meehanite, for example, by
conventional methods. Formed therein are series of
ratio which is achieved through the use of properly
placed pasageways.
This construction makes feasible
passageways which extend transversely of the plate from edge to edge. The generally vertical extending webs left 25 the use of a material such -as cast iron or the like, the
characteristics of which are h_ighly desirable in such a
between passageways might be of a number of configura
tions, as is seen in FIGURES 1-4. In such plates lifting
heat treating operation. The plates are machined and
annealed according to a prescribed regimen to produce
lugs are castintegrally‘with predetermined webs adjacent
opposite ends ofthe plate. In the alternative, passage
a product which will not vbend or warp outside of pre
scribed limits and which will maintain a high finish
Ways of a configuration similar to that shown in FIGURE
5 might be cast. In such case, separate shafts having lift
Y ing lugs at their opposite ends are inserted through special
ly cast passageways of different configuration adjacent op- ~
The foregoing explanation is intended Yto be illustrativev
only and not deñknitive and the scope of the invention
Quarterinch rounds are also machined on the edges of
lower surfaces, a high tolerance finish on each of said
throughout its useful life.'
should'i‘be limited only by the appended claims.
posite ends of the plate. After rough casting, a stress
I claim:
relieving operation is performed on the plate at a tempera 35
l. A thermal Iflattening plate for rolled metal sheet
ture in the neighborhood of 1100 degrees F. Of primary
comprising a plate having a predetermined substantial
importance here is that the annealing temperature be
length and a predetermined lesser Width, said plate having
higher, in this case in the neighborhood ofl 200 degrees
upper and lower surfaces, said plate Vbeing composed of
higher, than any temperatures to which the plate may
be subsequently subjected. After the stress relieving op 40 cast metal, a series of laterally disposed> passageways in
said plate extending therethrough, said pass-ageways sepa
eration, the plate is rough machined on its upper and lower
rated by a series of transverse walls joining the upper and
surfaces to roughly established predetermined tolerances.
surfaces and a'plurality of lifting lugs extending from
each of the longitudinal edges of said plate.
2. The ñattening plate of claim l further characterized
the plate itself, the passageways` and the lifting lugs in
the case of integrally cast lifting lugs.
' After the rough machining, a second stress relieving
operation is performed on the plate at a temperature in
l in that said cast metal is cast iron.
3. A thermal flattening plate for rolled metal sheet
the neighborhood of 1100' degrees F., a duplicate of the
previous stress relieving operation.
^ VAfter the second stress relieving operation, a fine ma
Vcomprising a plate, said plate including relatively thin
50 upper and lower walls having predetermined substantial
chiniugoperation is performed on the upperand lower
surfaces of the plate to establish the predetermined toler
.'ances. VIn these plates, as has hereinbefore been set out, j ,
lengths and predetermined lesser widths, a network of
laterally extending webbing connecting said walls and
forming a series of laterallyy extending passageways
through said plate, said‘walls and webbing being com
the permissible variation in flatness is .005 inch in 13 feet,
55 prised of cast metal and fonned integrally, a high toler
while a number 125 micro finish-is required.
ance finish on the outer surface of each-'of said walls and
` The use and operation of ‘this invention isas follows:
' Plates of this nature are commonlyrused in large heat
treating furnaces-to support flattened sheets of magnesium
or the like. 'I‘hey are stacked with sheets of metal pressed
Ybetween theirfopposed surfaces and then subjected to
temperatures which might be in the neighborhood of >900
degrees F. for periods of up to 24 hours.
i After such time :has elapsed, the platesY and sheets are
a plurality of lifting lugs extending along the longitudinal
edges of said plate _and formed integrally with said
j 4. Thel flattening plate of claim 3 further characterized
in that said webbing comprises a plurality of longitudi
nally spaced, laterally disposed webs, each of said webs
being inclined at an angle to said walls.
5. 'I‘he flattening plate of claim 4 further Vcharacterized
normally removed to the atmosphere while still at a tem
that alternate websfare disposed in oppositely inclined
perature ranging between 200 and 500 degrees F. rIr'his 65 in
attitudes to corresponding walls.
rapid change of environment, of course, produces high
thermal stresses Vthroughout the flattening plate. The
plates embodying this invention lare constructed in such
. 6. _ The ñattening plate of claim 5 further characterized
in that said Vlifting lugs com-prise a pair of'lugs on each
of ’saidY longitudinally extending edges, Veach Voneof said
a manner that these thermal stressesV do not result in a 70 lugs being integral with anV oppositely inclined web on
warping to a degree inconsistent with required tolerances.
y Platesvof relatively large size, such as these, would'be
of great weight if they were solid. In such case, the bend
the same edge of said plate.
7..A _thermal flattening plate for-rolled metal sheet
comprising a plate consisting of cast V'Meehanite metal,
relatively thin upper and lower Walls having predeter
viously of a very high order. By providing transversely 75 mined substantial lengths and predetermined lesser
'ing stresses developed during handling operations are ob- Y
Widths, a network of laterally extending webbing con
necting said Walls and forming a series of laterally eX
tending passageways through said plate, said walls and
webbing being formed integrally, the surfaces of said
walls being ñat to the extent that they de not vary more
than .O05 inch in 13 feet, a high tolerance finish on the
outer surfaces of said walls and a plurality of lifting lugs
extending along the longitudinal edges of said plate and
formed integrally with said webbing.
8. The thermal flattening plate of claim 7 further
characterized in that said high tolerance ñnish is in the
neighborhood of a number 125 mie-ro-ñnish.
9. The thermal flattening plate of claim 7 further
characterized in that said plurality of lifting lugs include
a pair of lugs on each of said longitudinal edges, said lugs
being formed integrally with said webbing, said lugs
being positioned to equalize stress throughout the length
of said plate when it is lifted.
References Cited in the tile of this patent
Budke - _______________ __ Dec. 4, 1900
Schnetzer et al. _ ______ __ Sept. 25, 1934
Great Britain _____ __'..__ Apr. 20, 1939
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