Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to novel retread molds
adapted for manual, semi-automatic, or full automatic opera-
tion preferably in bag or bladder retreading operations, and
a primary object is the provision of a mold which is efficient
in operation yet constructed with simplicity to enable opera-
tion thereof by relatively untrained personnel with safety
while providing long term machine life and obtaining retread
tires of excellent quality.
A construction in accordance with the present
invention comprises a retreading mold comprising a pair of
relatively movable platens, each platen carrying a matrix
~- means. First and second bead aligner wheels are carried by a ~ 1
respective first and second of the platens. The bead aligner ;
wheels are in opposed relationship to each other. An annular
bladder is disposed between the platens with the bladder
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having first and second innermost peripheral marginal portions.
~; The first and second innermost peripheral marginal portions
are in overlying relationship upon the first and second bead
aligner wheels. First means are provided for creating a her~
metically sealed annular gap between the terminal edge of the
first innermost peripheral marginal portion, an outboard por-
tion of said first innermost peripheral marginal portion and
said first bead aligner wheel. Second means are provided for ~ ~
creating a hermetically sealed annular gap between a terminal ~;
edge of the second innermost peripheral marginal portion, an
outboard portion of said second innermost peripheral marginal
portion and said second bead aligner wheel. -~;
The invention will now be described with reference
to the accompanying drawings which show a preferred form
thereof and wherein~
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Figure 1 is a perspective ~ront view of a novel
automatic retreading machine constructed in accordance with this
invention, and illustrates a pair of platens in the open position
thereof carrying segmented matrices with a tire located upon a
lower bead aligner wheel.
Figure 2 is a front elevational view of the machine
of Figure 1 partially in cross section, and illustrates the
matrices closed and a bladder under pressure maintaining a tire
to be retreaded in conformity with the interior of the matrices.
Figure 3 is a cross sectional view taken generally
along line 3-3 of Figure 2. and particularly illustrates means
for imparting motion to the bead aligner wheels and the drive
for relatively moving the platens carrying the matrices relative
to each other.
Figure 4 is a fragmentary enlarged sectional view of
a tire positioned within the closed matrices.
Figure 5 is a fragmentary enlarged sectional view
of a tire positioned within the opened matrices, and particularly
illustrates ~3~manner in which a partial vacuum retains the
20 tire beads against the bead aligner wheels. ~ -
Figure 6 is a fragmentary top plan view of the bladder
associated with the machine of Figures 1 through 3, and
illustrates raised ribs upon an exterior surface defining there-
between vent means or passages terminating short of enlarged beads
at inner ed~ges of the bladder. ;
Figure 7 is a sectional view taken generally along
line 7-7 of Figure 6, and more fully illustrates the raised beads
above the exterior surface of the bladder and notches in opposing ~
surfaces of the beads defining means for permitting the intro- ,
duction of fluid into and the removal of fluid from the~ ladder
interior.
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Figure 8 is a fragmentary enlarged cro~s se~tional
view taken along line 8-8 of Figure 6, and more fully illustrates
the manner in which the notches of the bladder beads are in
axial alignment.
Figure 9 is a view looking axially at one of the
pair of bead aligner wheels of this invention, and illu~trates a
circular continuous uninterrupted sealing rib and a plurality of
venting grooves adapted to be placed in fluid communication with
atmosphere through bores in a flange of the bead aligner wheels.
Figure 10 is an axial sectional view taken through a
pair of the bead aligner wheels o the invention, and illustrates
the manner in which fluid is introduced into the bladder as well
as the manner in which air is vented to atmosphere from between
the exterior surface of the bladder and an interior surface of
a tire undergoing a recapping operation.
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Fi~ure 11 is a fragmentary elevational view partially
in section of a modification of the machine of Figures 1-~, and
illustrates the manner in which the diameter of a tire is fore~
shortened by being mechanically clamped to the bead aligner wheels
in lieu pf vacuum clamping to be described hereinafter~wiith
respect to the machine of Figures 1-3.
Figure 12 is a sectional view identical to Figure 11
but illustrating the matrices in their closed position.
Reference is first specifically made to a machine 10
of Figures 1 through 3 which includes a conventional base 11
which has secured thereto in a conventional manner a pair of
upstanding cylindrical supports 12,13. An upper platen 14 is ,
fixedly secured to an upper end portion (unnumbered) of the
supports 12,13 by nuts (unnumbered) in the manner readily
apparent from the upper right hand portion of Figure 2. The
upper end portions (unnumbered) of the supports 12,13 are, of
course, threaded to receive ~he nuts and the latter may be
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adjusted or threaded to achieve aliynment between the upper
fixed platen 14 and a lower movable platen 15.
The movable platen 15 is provided with conventional
bushings (unnumbered) which surround the support~ 12,13 and
thus the platen 15 may be readily moved between the open
position (Figure 1) thereof and the closed position illustrated
in Figure 2.
Means for imparting relative movement between the
platens 14,15 is generally designed by the reference numeral 20
and includes an electric motor 21 connected to a suitable elec-
trical source (not shown) which drives a sprocket 22 keyed to an
output shaft 23 of a gear reducer 24. A drive chain 25 is ~ ~
entrained about the sprocket 22 and about a sprocket 26 (Figure 2) .:
suitably secured to a tubular stub shaft 27 which in turn is
welded or otherwise secured to an internally threaded nut 28. A ~ :
reciprocal member 30 in t~e..~form of a screw is threaded within
`. the nut 28 in the manner readily apparentf~:.o.m~Figures 2 and 3. `.
A lower end portion 31 of the screw 30 is capable of descending : ~.
into a suitable lubricant, such as Gil 0, maintained within a
generally cylindrical reservoir or sump 32. Accordingly, upon .
the ascent of the screw 30, the oil deposited upon the end ~:
portion 31 will maintain the threads (unnumbered) of the nut
28 continuously lubricated during the reciprocal motlon imparted
: to the platen 15.
An upper end portion 33 of the screw 30 is provided
; with means, generally designated by the reference numeral 35,
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- for achieving self-centering between the platen 15 and the
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platen 14. The means 35 is simply a convex surface on the end `; ~.
portion 33 of the screw 30 which bears against a planar
(unnumbered) surface of the platen 15. Thus, if there is any mis~
alignment of~a minor nature between the platens 14,15 and the .
matrices associated therewith to be described more fully herein- ~ :~
after,the-~platen 15 will tilt or cock as need be to an extent
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permitted by -the bushings (unnumbexed) associated with the
supports 12,13 thus assuring alignment between the matrices
and the tire therein. Furthermore, the platen 15 though of a
relatively rigid construction can still flex somewhat under the
force applied thereto by the screw 30 and this in turn achieves
a self-adjusting or self-centering between the platens 14,15
and the matrices carried thereby.
An upper bead aligner wheel 40 and a lower bead
aligner wheel 41 (Figures 2, 3 and 10) are reciprocally carried
by the respective platens 14,15 and are mounted thereon for
relative reciprocal movement toward and away from each other
in a conventional manner. More specifically, a pair of fluid
motors 42,43 carried by the upper platen 14 include identical
; pistons 44 (only one of which is illustrated in Figure 3) which
are secured to the upper bead aligner wheel 40 for imparting
motion thereto in a conventional manner. Likewise, fluid motors
45,46 carried by the lower platen 15 include piston rods 47
(only one of which is illustrated) for reciprocating the bead
aligner wheel 41 in the manner readily apparent from Figure 3.
During the reciprocal motion imparted to the bead
aligner wheels 40,41 guidance is provided by guide rods 50,51
secured to the bead aligner wheel 40 and by guide rods 52,53
(Figure 2) secured to the bead aligner wheel 41. The rods 50,51
and 52,53 are slidably received in tubular guides 54,55, res-
pectively, (only one of each being shown in Figure 2) carried
by the respective platens 14,15. -
Conventional segmented matrices 56,57 are carried -~
by the platens 14,15 and are operative in a conventional manner.
~hough specifically utilizing segmented matrices 56,57, the
machine 10 may be modified in the manner to be described
hereinafter in order that the same can utilize "full" or non-
segmented circular matrices.
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Reference i~ now made specifically to Figure 10
which illustrates the bead aligner wheel~ 40,41 in more specific
detail. Since the bead aligner wheels 40,41 are essentially
of an identical construction like re~erence numerals have been
applied thereto. The bead aligner wheels 40,41 each include
opposing sealing surfaces 60,60 which are essentially normal
to the axis of the bead aligner wheels 40,41 and to the axis
of the screw 30. Radially outboard of each of the sealing
surfaces 60,60 is a raised continuous uninterrupted circular ~ :
rib 61,61 (Figures 9 and 10) each of which is cooperative with
a bladder 65 in a manner to be described more fully hereinafter.
Radially outboard of each rib 61,61 is a generally curved shoulder
: or surface (unnumbered) which has formed therein a plurality of
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bleed notches or grooves 62,62 each of which terminates at a .. :
bore 63 formed in a flange 64 of each bead aligner wheel 40,41. : ~.
The notches 62 and hores 63 cooperate with the bladder 65 in a
manner to be described more fully hereinafter to bleed entrapped
air from between an exterior surface of the bladder 65 and an
interior surface of a tire T be.tween the matrices 56,57 to
atmosphere during the pressurization of the interior of the
bladder 65.
It is mandatory to preclude the bladder 65 from
being pinched during the closing of the matrices 56,57 as well
as during the closing of the bead aligner wheels 40,41 and
accordingly, one or both of the bead aligner wheels 40,41 are .
provided with a plurality of axially projecting bosses 66 .
(Figure 9). In the embodiment of the invention illustrated
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the bead aligner wheel 41 has four such bosses 66 and during
the closing of the bead aligner wheels 40,41 the bosses 66 ~:
contact the sealing surface 60 of the bead aligner wheel 40 and ~ ;;
assure that the bladder disposed therebetween will not be
pinched. The bosses 66 are also preferably disposed with their .::
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axis on a common circle ~uch that th0y alqo serve as means for
looating ~h~bladder upon the bead aligner wheels ~0,41 as will
be described more fully hereinafter.
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Inasmuch as it is necessary in keeping with the ~ ;;
invention to inflate the bladder 65 a pressurized fluid, which
is preferably heated air, is introduced into the space between
the sealing surfaces 60,60 of the bead aligner wheels 40,41
through a part 67 which is in turn connected by a pipe 68,
(Figure 1) and a flexible conduit 70 to a suitable source (not
shown~ of pressurized fluid as, for example, hot air or a
heated, non-explosive, non-compressible liquid or a source of
steam o~ the like. Suitable conventional control means within
` a control panel 71 (Figure 1~ are provided for maintaining
pressure internally of the bladder 65 at a desired level and
suitable means may be provided for circulating the fluid media
within the bladder 65. As an alternative. the fluid media n~d
not be heated nor circulated within the bladder 65 and instead
may be utilized simply to inflate the bladder 65 to a desired
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pressure with the heat required for the curing operation being
achieved by conventionally heating the matrices 56,57
electrically or by the circulation of a heating fluid there-
through.
Reference is now made specifically to Figures 6-8
of the drawings which more specifically illustrates the bladder
65 as a generally annul~ member of a U-shaped cross section
(Figure 7) defined by a bight portion 72 and a pair of arms or
legs 73,74 terminatlng in inboardmost terminal edges or beads
75,76 respectively. The cross sectional thickness of the Iegs
- 73,74 is thickest adjacent the beads 75,76 and tapers pro-
gressively ra~ially outwardly to a thinner though generally
uniform cross sectional thickness in the area of the bight
portion 72. This tapering permits the bight portion 72 to con~
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~orm to the in~erior configuration of the t.ire prior to outward
progressive conformation of the legs 73,74 against the inner
surface of the tire sidewalls, a~ will be described more fully
hereinafter. ~n exterior surface 77 of the bladder 65 includes
a plurality of radially directed raised ribs 78 between which
are defined valleys 80 which serve as bleed or venting passages
for air entrapped between the inner surface of the tire side-
wall and the exterior surface 77 of the bladder 65 in con]unc-
tion with the bleed grooves 62 and the notches 63 of the bead .. ~:
aligner wheels 40,41. In other words, as the bladder 65 is
being inflated (Figure 10) the bight portion 72 thereof begins
to progressively conform to the inner surface of the crown ::
(unnumbered) of the tire T and in doing so, air therebetween
is forced toward the tire beads (unnumbered). Air which would
otherwise be thus entrap.ped is expelled through th~ vents i8~
at least some or all of which are aligned with the notches 62 of
the bead aligner wheels 41,42 resulting in the passage ~f th.is
air to atmosphere through the bleed bores 63 of both bead .
aligner wheels 40,41. -
20 ' In order to assure that the bladder 65 is pressurized
the beads 75,76 of the bladder 65 have respective aligned
notches 80,81 (Figures 7 and 8~. Therefore, upon the intro-
duction of fluid into the bladder 65, in the manner indicated
by the unnumbered headed arrows in Figure 10, the aligned notches .~
80,81 define port means for the introduction of such fluid into ~... .
the bladder 65, as well as the exhausting therefrom.
A highly important feature of this invention is
the manner in which annular chambers A ~Figure 10) are formed .
between the sealing surfaces 60,60, the ribs 61,61 and the
inboardmost portions of the arms 73,74 of the bladder 65. The
significance of this featureis more specifically applicable-to
full circle matrices, as opposed to segmented matrices. In the .~:
former the normal diameter of the tire T must be foreshortened
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in order that the full circle matrices may be closed without
closing upon the tire T and/or assuring that the tire will be
subsequently expanded from its foreshortened condition to seat
properly within the full circle matrices. In order to fully
appreciate this, reference is now made to Figures 4 and 5 of
the drawings.
~ In Figure 4, the matrices 56, 57 are shown closed
- and the inner surfaces thereof are in perfect conformity with
the exterior of the tire T. The bladder 65 is, of course, pres-
surized at this point and due to the pressurization thereof which
is greater than atmosphere, the annular channels A are actually
; under a partial vacuum and therefore the beads 75, 76 are in
hermetic sealing relationship with the surfaces 60, 60 of the
~ bead aligner wheels 40, 41 and a tight hermetic seal is achieved
;` between the ribs 61, 61 and the portions of the legs 73, 74 of
the bladder 65 against which they contact. Therefore, upon the -~
opening of the matrices, which in this case are full circle ma~
trices, the parti~al vacuum within the annular chambers A holds
the portions o~ the bladder legs 73, 73 inboard of the ribs 61,
61 tightly against the bead aligner wheels 40, 41. Accordingly,
as the bead aligner wheels 40, 41 move away from each other, the
diameter of the tire T is foreshortened (Figure 5) thereby per-
mitting the matrices 56, 57 to be fully closed prior to the
movement of the bead aligner wheels 40, 41 toward each other to `
achieve the positive seating between the tire T and the matrices,
as shown in Figure 4. Thus, the built-up tire may be positioned
in the manner shown in Figure 5 and when the bladder is pres- -
surized, it will assume the position shown in this same Figure. ~ ~
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Thereafter, and with the bead aligner wheels 40, 41 spread
apart, the full circle matrices are closed and thereafter the
bead aligner wheels may be moved to the closed position of
Figure 4 incident to the performance of the curing operation.
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Another machin~ 10' con~3tructed in accordance with
this invention is illustrated in Figures 11,12 and components
thereof corresponding to those of the machine 10 of Figures 1
through ~, bear like reEerence numerals, though the same have
been primed. In keeping with the construction of the machine 10,
the same as matrices 56',57', but these are full circle matrices,
not segmented. As compared to the machine 10, the machine 10'
utilizes the aoncept of foreshortening a tire T' prior to the
closing of the matrices, but the beads thereof are mechanically
gripped in the manner illustrated in Figure 11. The mechanism
includes a plurality of rods 90 passing through suitable guide
bores (unnumbered) and terminating in angular ends 91. The
opposite ends of the rods 90 are rotated and reciprocated by
conventional apparatus.
The tire T' is inserted between the matrices 56',
57' when the latter and the platens 14',15' are in their Eully
opened positions after which the bead aligner wheels ~0',41'
are moved toward each other and the beads (unnumbered) of the
tire T' are automatically located. Thereafter, the rods 90
are rotated from an out of the way position to the position
shown in Figure 11, and the bead aligner wheels 40',41' are
retracted to the illustrated position of Figure 11. The bladder
65' is then inserted in the manner illustrated in Figure 11 after `~which the full circle matrices 56',57' are closed. Once the
latter are closed the bead aligner wheels 40',asll then move ~-~
toward each other to their final position (Figure 12j and
fluid is introduced into the bladder 65' to pressurize the
interior sufficiently depending, of course, upon the cure time,
temperature, tire compound, etc. involved.
The machines 10 and 10' are provided with suitable
control means including, of course, the control cabinet 71 and
the components thereof which, for the most part, are con~
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ventional. How~ver, in keeping with this invention, the
circuitry for the motor 21 inclucles a switch (not shown)
carried by either of the platens 14,15 such that upon the
closing of the latterl the switch will be activated to
de-energize the motor 21. Preferably the switch actuates through
a trip relay of a conventional construction on which the ampe~age
may be adjusted to automatically shut off the drive motor 21 when
the matrices 56,57 or 56',57' come together with sufficient force.
When the motor ~1 shuts off a conventional break automatically
locks, although the latter is not an absolute requirement of the
system. However, due to the adjustable nature of the rel'ay, it
is necessary to adjust the distance between the platens at any
time even if the matrices are changed or when spacers are inserted
in a conventional manner, and this also makes the machines 10,10'
self-adjusting.
While preferred forms and arrangements of parts have
; been shown in illustrating the in~ention, it is to be clearly
understood that various changes in details and arrangements of
~, parts may be made without departing from the scope and spi~rit
of this disclosure.
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