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Патент USA US3046628

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July 31, 1962
J. c. CARPENTER
3,046,625
HOT TOP AND WIPER STRIP CONSTRUCTION
Filed 001‘,- 15, 1960
IN VEN TOR.
JOEL C. CARPENTER
W MW“
BY -
I
r
3,946,625
Patented July 31, 1962
2
of a single planar strip contacting a surface of'the re- '
3 046 625
nor TOP AND wnisn srnrr coNsTRUcTioN
Joel C. Carpenter, Chagrin Falls, Ohio, assignor to Ogle
bay Norton Company, Cleveland, Ohio, a corporation
of Delaware
Filed Oct. 13, 1960, Ser. No. 62,384
11 Claims. (Cl. 22-147)
This invention relates to a hot top and particularly to
fractory bottom ring or the attaching portion of the
wiper strip may consist of angularly disposed integral
parts contacting angularly disposed surfaces of the re
fractory bottom ring.
'
During a pouring operation as the molten metal enters
the clearance space between the hot top and the inner
wall of the ingot mold the pourer should momentarily
interrupt the pouring operation to allow the molten metal
an improvement in the wiper strip arrangement [for the 10 in said space and in contact with the wiper lip of the
wiper strip to sui?ciently solidify to form a seal against
hot top.
further rising of the metal in the clearance space. This
Composite reusable hot tops of the ?oating type are
inserted into the upper end of an ingot mold and tem
porarily supported therein for the pouring of molten
solidi?cation of the molten metal in the clearance space
is facilitated by its contact with the wiper lip of the
metal into the mold and hot top to produce an ingot as 15 wiper strip since the metal wiper strip produces a chill
in the molten metal that has risen into the clearance
is well understood in the art. Efforts are‘ made to keep
the clearance space between the outside of the hot top
space.
‘
particularly at its refractory bottom ring and the inside
The wiper lip of these wiper strips is of such width
as to attempt to span across the clearance space between
wall of the ingot mold to a minimum. However, mold
manufacturers’ allowable tolerances are such that said 20 the hot top and the inner wall of the mold and as the
hot top is inserted into the open top end of the mold said
clearance space may vary substantially in width due to
lip should ?ex and accommodate itself in the clearance
variations in the size of the ingot mold or the opening
at the top of the ingot mold.
,
During .a pouring operation the molten metal that
normally ?ows into the clearance space between the
outside of the hot top and the inside wall of the ingot
mold must be sealed again-st rising too far in said space
or over?owing the upper edge of the mold. If the molten
metal rises too far in the clearance space and then solidi
?es therein dif?culty will be experienced in stripping the
hot top from the sinkhead of the solidi?ed ingot. If the
molten metal rises in the clearance space and over?ows
the top of the ingot mold such over?owing metal when
solidi?ed will produce what is known as “hanger” ingots,
space.
However, in those instances wherein the hot top is
used with a mold having a small opening the wiper lip
of the wiper strip may extend so far over the top of
the mold as to prevent the entry of the hot top into the
mold thereby causing the hot top to be suspended from
or hung on the top of'the mold by the wiper'lip.
‘Conversely, in the situation wherein the hot top is used
with a mold having a large size opening the wiper lip of
the wiper strip may not extend outwardly from the hot
top su?iciently far to engage the inner wall of the ingot
mold when the hot top is inserted therein thereby pre- ',
~
that is ingots which are not free to contract relative to 35 venting the desired seal.
The present invention contemplates a hot top and wiper
the mold as the ingot solidi?es and this condition would
tend to produce undesirable “hanger” cracks in the ingot.
The ideal situation for the effective and e?icient teem
strip construction such that the wiper lip of the wiper
strip will extend outwardly from the periphery of the
ing of the molten metal is therefore to provide as com
hot top and its bottom ring a suf?cient distance to assure
plete a seal as possible against undesirable rising of the 40 engagement of the lip with the inner wall of the ingot
mold when the clearance is large and yet said lip and
molten metal in and through the clearance space.
the attaching portion ‘of the wiper strip will be free to
In those instances wherein the clearance space between
yield and ?ex as the hot top is inserted into. the ingot
the hot top and the inside wall of the mold is a close
mold when the clearance is small so as to conform it
one it is relatively easy to effect a ‘good seal again-st the
molten metal rising too far in or over?owing such clear 45 self to the clearance space between the hot top and'
the inner wall of the mold and avoid hanging the not top
ance space, although the operation of inserting the hot
on'the mold by the wiper lip.
.
i
top into the ingot mold under this condition will be
In accordance with the invention the wiper lip of the
much more di?icult.
wiper strip will function effectively and e?iciently in
In those instances wherein the clearance space between
molds having the larger size openings and also in molds
the hot top and the inside wall of the ingot mold is large
having the smaller size openings. The versatility of the
it is, of course, more di?icult to effect the necessary
wiper strip embodying the invention assures an ef?cient
seal against the rising of the molten metal in said space
seal for the molten metal that normally rises into the
although under this condition the operation of inserting
clearance space between the hot top and the inner wall '
the hot top into the ingot mold may be relatively easy.
Inasmuch as the size of the hot top and its refractory 55 of the ingot mold and therefore avoids likelihood of
“hanger” ingots or of “hot top stickers” which prevent
bottom ring can be closely controlled, the clearance vspace
the removal of the hot tops from the sinkhead of the
between the outside of the hot top and the inside wall
solidi?ed ingot.
of the ingot mold depends entirely on the size of the
The invention more speci?cally contemplates interpos
opening at the top‘ of the mold.
In an e?ort to obtain the optimum condition just re 60 ing between the hot top structure and the wiper strip
in the zone of the junction between the attaching portion
ferred to resort has been had to the use of what is known
and the wiper lip of the wiper strip yieldable backing '
in the art as wiper strips. These wiper strips are usually
material which functions initially to'cause the wiper lip '
formed of rather ?exible thin sheet metal that may be
to’ be disposed in maximum extended position so as to
separate from or secured to the refractory bottom ring
and they have a bottom ring engaging or attaching por 65 assure its engagement with the inner wall of ingot molds
having the larger size openings but which backing mate
tion which, in turn, has an integral wiper lip extending
,angularly ‘from an edge of said portion outwardly of the
periphery of the bottom ring and adapted to engage the
ing portion when the hot top is inserted into the mold. 1
inner wall of the ingot mold as the hot top is inserted
In accordance with the invention the term “yieldable
rial yields to assure ?exing of the wiper lip and attach
into the mold and is positioned therein during a pouring 70 backing material” is intended to cover‘compressible ma
operation.
The attaching portion of the wiper strips may consist
terial as well as displaceable material.
The backing ma‘; , V
terial also enhances the chilling effect ofthe wiperst'rip
'
3,046,625
4
when the molten metal rising in the clearance space be
tween the hot top and the ingot mold contacts the wiper
strip and this, of course, increases the e?iciency of the
wiper strip and hastens the desired solidi?cation of the
metal in the clearance space to form the required seal.
Although the invention at least in certain of its aspects
can be used in connection with various forms of wiper
strips, its use will be referred to herein in connection with
top inserted farther into the ingot mold and the free edge
of the wiper lip of the wiper strip engaging the inner wall
of the ingot mold,
FIG. 4 is a top plan view of the refractory bottom ring
and wiper strip shown in the previous views and detached
from the hot top, and
FIG. 5 is a separated elevational view of the refractory
‘bottom ring and wiper strip shown in FIG. 4.
Referring to FIG. 1, the composite reusable ?oating
that form of wiper strip wherein the attaching portion
from which the wiper lip extends engages the outer periph 10 hot top illustrated therein comprises a metal casing
formed, in this instance, of lower and upper parts 10 and
cry of the bottom ring since the invention is particularly
i1 suitably secured together as is well understood in the
useful with said type of wiper strip.
art. The metal casing of the hot top is lined with a suit
In a hot top construction wherein the refractory bot
able refractory linging 12 which may be of any well
tom ring nests in the attaching portion of the wiper strip
known form. The refractory bottom ring 13 is secured
which engages and extends vertically of the outer periph
to the lower end of the hot top by attaching clips 14 as
ery of the bottom ring, the wiper strip is relatively stiff,
is well understood in the art. The wiper strip shown,
particularly at the junction between the attaching portion
for purposes of illustration, has an attaching portion com
thereof and the integral angularly extending wiper lip.
posed of a part 15 which underlies and contacts the bot
This is true even though the wiper strip may be notched
or slit at critical locations to increase its ?exibility. In 20 tom of the bottom ring and a part 16 integral with the
part 15 and extending substantially at right angles thereto
this type of construction the engagement of the attaching
and vertically of the outer periphery of the bottom ring.
portion of the wiper strip with the outer periphery of the
refractory bottom ring prevents the attaching portion it
The wiper lip 17 of the wiper strip is integral with the
self from ?exing, with the result that entire reliance must
be placed on the limited ability of the wiper lip itself to
?ex in accommodating itself to the inner wall of the mold.
The invention further contemplates in those construc
part 16 and extends angularly and outwardly from the
upper edge of said part 16. The open upper end of an
ingot mold 18 is indicated in FIGS. 1 through 3.
The hot top with the bottom ring and wiper strip at—
tached thereto and prepared for a pouring operation is
inserted into the open upper end of the ingot mold initi
ally a predetermined distance and is held in inserted posi
tion by means of wooden blocks (not shown but well
known in the art) until a period in the pouring operation
tions wherein the attaching portion of the wiper strip con
tacts the bottom ring, particularly the outer periphery of
the ring, relieving a portion of that part of the bottom
ring which heretofore was contacted by the attaching
portion of the wiper strip so that the attaching portion of
the wiper strip is made susceptible of movement inwardly
toward said part of the bottom ring during the insertion
ofithe hot top into the ingot mold and thus supplements
the ?exing of the wiper lip of the wiper strip in allowing
the wiper lip to properly accommodate itself to the inner
wall of the mold.
Speci?cally where the attaching portion of the wiper
strip surrounds and contacts the outer periphery of the
bottom ring, a portion of the vertical surface of said pe
riphery of the bottom ring is relieved or beveled inwardly
and upwardly from a point at or above the bottom out
side edge of the ring. This provides a space between a
part of the attaching portion of the wiper strip and the
bottom ring so that said attaching portion may move or
when said blocks are destroyed or knocked out of posi
tion and thereafter the hot top rests on the metal in the
ingot mold ‘and can have limited movement relative to the
mold during the solidi?cation of the ingots as is well un
derstood.
When the hot top is inserted into the mold the wiper
lip 17 of the wiper strip is adapted to accommodate it
self to the inner wall of the mold and to engage the latter
as indicated in FIG. 3 and for a purpose understood in
the ‘art ‘and more fully referred to hereinafter.
Although the invention in all or some of its aspects
may be used advantageously in connection with various
wiper strip and hot top constructions, it will be explained
herein as embodied in the bottom ring and wiper strip
?ex into said space, particularly when the hot top is being
combination disclosed in the copending Urmetz and Car
inserted into a mold with a smaller size opening.
penter application Serial No. 62,757, ?led October 14,
The
1960 inasmuch as it has particular utility when so em
provision of said space behind the attaching portion of
the wiper strip lessens the chilling effect of the wiper 50 ployed. Only one embodiment of the bottom ring and
wiper strip combination shown in said Urmetz and Car
strip on the molten metal and this might lessen the effec
penter application Serial No. 62,757 is illustrated herein
tiveness of the seal, however, the yieldable backing ma
but it will be understood that the invention could be em
terial previously referred to ?lls said space and functions
ployed in connection with the other embodiments of the
to increase the chilling effect of the wiper strip and also
acts to force the attaching portion of the wiper strip out 55 bottom ring and wiper strip combination shown in said
Urmetz and Carpenter application as will be later pointed
wardly from the periphery of the bottom ring and thus
out.
move the wiper lip outwardly a maximum distance from
As already stated the attaching portion of the wiper
the bottom ring. This enables the hot top construction
strip illustrated and composed of the parts 15, 16 and 17
to be used with a relatively large size mold and still have
has the bottom ring 13 nested therein with the part 15
the wiper lip engage the inside wall of the mold and pro
extending beneath and contacting the underside of the
vide maximum e?‘iciency for the sealing off of the molten
‘bottom ring and the part 16 extending vertically of and
metal in the clearance space between the hot top and
contacting the outer periphery of the bottom ring. The
the mold.
bottom ring and wiper strip combination is such that the
The speci?c details of and the advantages in the hot top
construction broadly described above will be pointed out 65 combination is handled and attached as a unit to the hot
top casing by means of the attaching clips 14. The
in the following description of an embodiment of the in
wiper strip is shown as constructed of a continuous stamp
vention which is illustrated in the accompanying drawing
ing extending completely about the bottom ring. How
which forms part of this speci?cation and wherein
ever, it will be understood that the wiper strip could be
FIG. 1 is a sectional view through a hot top construc
tion embodying the invention and shows said hot top as 70 formed of separate sections having their adjacent ends
overlapping and secured together as illustrated in a further
it is being inserted into the open upper end of an ingot
embodiment disclosed in said Urmetz and Carpenter ap
mold, a portion of said mold being indicated in section,
FIG. 2 is a view on a larger scale of the lower right
hand portion of FIG. 1,
plication Serial No. 62,757.
The wiper strip is formed of thin sheet metal having
FIG. 3 is a view similar to FIG. 2 but shows the hot 75 a substantial measure of ?exibility.
However, to increase
.
‘For
, 3,046,625
-
6
5
the ?exibility of the wiper strip, and particularly the
wiper lip 17 thereof, it may be provided with a number
of spaced slits particularly at the-corners, these slits being
indicated in FIG. 4 at 19, it being understood, however,
that the slits may vary in number from the four slits shown
depending on the particular con?guration of the ring wiper
ward movement because of said space and thus the ?ex-i‘
ing of the wiper lip is supplemented by inward movement
of the ‘part 16. This arrangement has been .found to
greatly facilitate the insertion into a tight mold of a hot‘
top equipped with the bottom ring and wiper strip com
bination.
’
‘
,
.
V
,
.
r
The provision of a space behind the part 16 of the‘
wiper strip might tend to reduce the chilling effect or heat
Also the wiper lip 17 is provided with slots. or cut;
absorption of the wiper strip upon or from the molten
outs 19a through which the attaching clips 14 extend.
In some instances the outer periphery of the bottom 10 metal entering the clearance space between the hot top
and the inner wall of the ingot mold. In order to pre
ring and the wiper strip are ?uted or ‘sinuous and it is
vent this and also to maintain the part [16 of the wiper strip
desirable to slit the wiper lip 17 between the curved sec
in its most outward position with a resultant outward’
tions of the ?utes, as well as at the corners to increase
positioning ‘of the wiper lip 17 the space between the
the ?exibility and enable the wiper lip to conform to the
contour of the inside wall of the ingot mold as the hot 15 relief or bevel surface >20‘of the periphery of thebottom
ring and the part 16 is ?lled/with a pressure'yieldable
top slides into place.
backing material 21 which, as previously de?ned, may be
As previously mentioned, an embodiment of the bottom
combination and the mold with which it is used.
'
ring and wiper strip combination disclosed in said Urmetz
and Carpenter application Serial No. 62,757 includes a
wiper strip formed of separate sections, the adjacent ends
of which overlap and are secured together and this pref
erably is at the corners of the wiper strip.
‘
The ?exibility of the wiper strip formed of united sec
tions as last referred to can be .maintained by joining
either a compressible material or a displaceable mate
rial. As illustrative .of a suitable material 21 reference
is made to steel wool, asbestos rope or other ?brous com-r
pressible materials. In addition, a displaceable ‘ mate-:
rial 21 can be used as, for instance, a ?owable or viscous‘
material can be employed.
'
'
,
,,
'
-
The pressure yieldable backup materialll becausejof.
the overlapping adjacent ends of the wiper strip ‘sections 25 its composition and texture when not subjected to yield:v
ing pressure functions to maintainor force the pa'rt716
together only at a single point near the junction between
of the attaching portion of the wiper strip and the wiper‘
the part 16 and the part 15 of the attaching'portion of
the wiper strip as this enables the 'overlap between the
upper surfaces of the parts 16 and the overlap. between
lip 17 thereof to their outermost position as clearly indi-~
cated in FIG. 2. Then when the hot top with the bottom
the Wiper lips 17 to be capable of relative movement, 30 ring and wiper strip combination is inserted farther into’
the ingot mold as, for instance, to the‘ position indicated
care being taken to provide sufficient overlap at the
in FIG. 3, the wiper lip 17 will be ?exed upwardly and
corners 'to prevent any danger of ,an opening occurring
the part 16 will be pressed inwardly of the space enabling;
between the overlapped portions when the wiper lip 17 is
in maximum extended position with respect to the pe
riphery of the bottom ring.
The wiper strip illustrated is, because of its angular
‘shape in cross section, less ?exible than is desirable and
the wiper lip 17 to readily accommodate ‘itself to the in?er'j
- wall of the mold and provide the requisite seal.
e
movement of the part 16 of the wiper strip will exert pres
sure on the backup material 21 and since said material is
yieldable it will either be compressed or displaced to allow;
consequently it is proposed to notch or slit-the wiper lip
such movement of the part 16. ' '
‘
~
f
17 at spaced locations as previously referred to, and
also to similarly slit or notch the horizontal part 15 of the 40 From the foregoing it will be seen that when, the hot
attaching portion of the wiper strip. Thisparrangement
top equipped with the bottom ring and wiper strip com-'
increases the ?exibility of the wiper strip. The ?exibility
of the wiper strip in the bottom ring combination illus
bination is inserted into a reasonably large mold, the wiper
lip 17 being forced to its maximum outward position by
the pressure yieldable backup material, will engage the‘
trated, wherein the vertical part 16 of the attaching por
tion of the wiper strip surrounds and engages the periphery 45 inner wall of the mold and thus assure maximum, possi
bility of obtaining a ‘good seal when the molten metal
of the bottom ring is lessened, inasmuch as said vertical
part 16 being backed up by the" bottom ring cannot move’
is teemed up through the clearance space between the,
or ?ex.
Hence reliance has to be placed largely on the
hot top and mold, such possibility of a good seal beingincreased by the enhanced chilling elfect on this molten
metal produced by the backup material in combination.
exing of the wiper lip 17 about the angular and thus
stiffened junction between the wiper lip and the part’16.
The present invention contemplates overcoming, this
di?iculty and increasing the ?exibility of the wiper strip to
enable the lip to accommodate itself- properly with respect
with the wiper strip.
the bottom ring with a relief or beveled surface portionv
inwardly against the pressure yieldable backup ‘material
~
7
1
When a hot top equipped with the bottom ring and,
Iwiper strip combination is inserted into a tight ingot mold;
to the inner wall of the mold, particularly in theinstance
the wiper lip 17 will ?rst engage the top corner edges of,
of a tight mold, by making provision for the vertical part 55 the ingot mold but because ofthe angle of engagement-v
16 of the attaching portion of the wiper strip to have.
the wiper lip 17 will be displaced upwardly and inwardly;
movement laterally relatively to the bottom ring. This
as the hot top moves downwardly in the mold. ‘In addi
provision is accomplished by providing the periphery of ‘v
tion, the vertical part 16 of the wiper strip will be pressed
t")
20.
This relief or beveled surface 20 may extend from or 60 21 and therefore because said material is readily com-'
above the lower outside edge of the bottom ring and up
wardly to the top of the bottom ring. Preferably the
pressed or displaced, the wiper strip will easily'conform
bottom ring surface that is engaged by the lower portion
the hot top and inner wall of the ingot mold. ;
to the ingot mold as the hot top moves‘downwardly, into '
relief or beveled surface 20 will have its lower starting
its ?nal position. This assures easy insertion of the'hot.
location spaced somewhat upwardly from the lower out- .
top in the mold together with maximum possibility ‘of
side edge of the bottom ring so as to provide a peripheral 65 effecting the required seal for the clearancespace betweenr _ ‘
of the part 16. The relief or beveled surface 20 on the
periphery of the bottom ring provides of course a space
between said periphery and the inner side of the part 16
a
'
Although a particular embodiment of the invention";
has been illustrated, and described ‘it willbe understood? '
that the invention is applicable to other ‘forms of, wiper; \
of the attaching portion of the wiper strip. Consequently 70 strips than those shown in the drawing and may be em
when a hot top equipped with the bottom ring and wiper
strip combination thus constructed is inserted into an ingot
mold and the wiper lip 17 is ?exed in accommodating it
self to the inner wall of the mold, the part 16 of the
attaching portion of the wiper strip can have limited in
bodied in various modi?cations and adaptations so long
as the same come within the scope of the appende
claims.
‘
Having thus described my invention I claim:
1. In a reusable, composite, ?oating hot top structure"
3,046,625
7
8
including a metal casing and a refractory bottom ring
7. In a reusable composite ?oating hot top structure
adapted to ‘be inserted into an ingot mold and including a
connected to said casing, a wiper strip having an attach
ing and bottom ring engaging portion and an integral
wiper lip extending angularly from an edge of said por
casing and a refractory bottom ring connected to the
lower end of said casing, said bottom ring having a
tapering relief extending inwardly of its outer periphery
and substantially completely around said ring, and a
wiper strip of sheet material having an attaching and
bottom ring engaging portion and an integral wiper lip
extending from an edge of said portion and outwardly of
tion and outwardly of the periphery of the bottom ring,
and pressure yieldable backing material interposed be
tween said structure and said wiper strip and extending
substantially completely around said structure in the zone
of the junction between said portion and said wiper lip of
the wiper strip.
10 the periphery of the bottom ring, said attaching and en
gaging portion having a part extending from the junction
between said portion and said wiper lip. and which part
overlies said relieved portion of said bottom ring and can
move into the space provided by said relieved portion
when the wiper lip is subjected to forces incident to its
engagement with the mold during the insertion of the hot
top structure into the mold, wherefore such insertion is
2. In a hot top structure as de?ned in claim 1 wherein
said bottom ring is shaped to provide an intervening space
between it and part of said attaching and bottom ring
engaging portion of said wiper strip and extending sub
stantially completely around said bottom ring while said
pressure yieldable backing material is located in said
space.
3. In a hot top structure as de?ned in claim 2 wherein
the outer periphery of said bottom ring is provided with
an inwardly relieved or beveled surface extending sub
facilitated due to the ability of said part to move into
said space.
8. In a hot top structure as de?ned in claim 7 wherein
20
stantially completely around said ring while said attach
ing and bottom ring engaging portion of said wiper strip
engages said bottom ring and overlies in spaced relation
the tapering relief on the outer periphery of said ring is
formed by a beveled surface extending upwardly and in
wardly from a point on the outer periphery of said bot
ship the inwardly relieved or beveled surface on the
tom ring while said attaching and bottom ring engaging
portion of said wiper strip contacts the outer periphery
of the bottom ring and said part of said wiper strip por
tion overlies in spaced relation said beveled surface and
said integral wiper lip extends from the upper edge of
said part.
periphery thereof.
4. In a reusable composite ?oating hot top structure
including a metal casing and a refractory bottom ring
and wiper strip unit connected to said casing, said unit
comprising a refractory bottom ring having its outer pe
riphery provided with an inwardly beveled surface ex
tending upwardly from a point adjacent to but above the
lower outer edge of the bottom ring and extending sub?
9. In a hot top structure as de?ned in claim 8 wherein
said attaching and bottom ring engaging portion of said
Wiper strip includes an integral ?ange underlying and
engaging the lower side of the bottom ring.
stantially completely around said periphery, a wiper strip
having an attaching portion including a horizontal part
10. A bottom ring and wiper strip unit for a reusable
engaging the underside of the bottom ring and a vertical 35 composite ?oating hot top structure and comprising a
part integral with said horizontal part and engaging the
refractory bottom ring having an outer periphery relief
outer periphery of the bottom ring below said point and
portion completely around said ring and a wiper strip of
overlying and spaced from said inwardly and upwardly
sheet material mounted on said bottom ring and having
beveled surface thereof ‘above said point, said vertical
an attaching and bottom ring engaging portion and an
part of said wiper strip having integral therewith at its 40 integral wiper lip extending angularly from an edge of
upper edge an outwardly and angularly extending wiper
said portion and outwardly of the periphery of the bot
lip, and pressure yieldable backing material interposed
tom ring, said attaching and engaging portion having a
between said beveled surface of said bottom ring and said
part extending from the junction between said portion
wiper strip and extending substantially completely around
45 and said wiper lip which overlies said relieved portion
the hot top.
of said bottom ring and which part can move into the
5. A bottom ring and wiper strip unit adapted to be‘
space provided ‘by said relieved portion when the unit is
secured to the lower end of the metal casing of a re
mounted on a hot top and the wiper lip is subjected to
usable composite ?oating hot top and comprising a re
forces incident to its engagement with the mold during
fractory bottom ring provided on its outer periphery and
extending downwardly thereof from its upper casing en 50 the insertion of the hot top into the mold.
ll. Abottom ring and wiper strip unit as de?ned in
gaging side with a beveled surface extending substantially
claim 10 and wherein said relieved surface portion of
completely around said periphery, a wiper strip having an
attaching and bottom ring engaging portion ?tting the
the bottom ring is provided with a beveled surface on
outer periphery of said bottom ring and overlying in
spaced relationship the beveled surface thereof, said at
taching portion of said wiper strip having at its upper
the outer periphery of the ring extending upwardly and
inwardly from a point on the outer periphery of the ring,
while said attaching and engaging portion of the wiper
edge an integral angularly and outwardly disposed wiper
lip, and pressure yieldable backing material interposed
strip surrounds and contacts the outer periphery of the
ring and said part thereof overlies said beveled surface
between said wiper strip and said beveled surface of said
bottom ring and extending substantially completely
around said ring.
6. A bottom ring and wiper strip unit as de?ned in
claim 5 wherein said attaching and bottom ring engaging
portion of said wiper strip includes a horizontal part un
derlying and contacting the underside of the bottom ring
and a vertical part contacting the outer periphery of the
bottom ring and overlying in spaced relationship the
beveled surface thereof and having the wiper lip at its
upper edge.
60
in spaced relationship thereto.
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,997,677
2,914,824
Charman ____________ -_ Apr. 16, 1935
Marcec _______________ -_ Dec. 1, 1959
548,988
Great Britain __________ __ Nov. 2, 194-2
FOREIGN PATENTS
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