CA1065795A - Treatment of tire making components - Google Patents

Abstract

Abstract of the Disclosure Apparatus for treating running lengths of tire ply stock, gum stock, chafer, chipper, and similar components of diverse widths by electron radiation from a high voltage electron accelerator in a shielded chamber, facilitates handling by plural parallel conveyors which can operate individually for lesser widths or in synchronism as one conveyor to carry greater widths through the treatment chamber.
Letoff and windup units are associated with individual conveyors and with the combined conveyors.

Description

The present invention relates to an apparatus for treating tire components. More particularly, the invention relates to apparatus for treating in running lengths the curable rubber-like compounds of which tire components are formed by subjecting such stock to controlled dosage of high voltage electron beam radiation.
It is known that treatment of compounds of rubber and rubber-like material with high voltage electron beam radia-tion can improve some physical properties of the compounds.
Apparatus for moving sheet and strip materials continuously through a field of electron radiation heretofore available has not been fully satisfactory and has lacked versatility.
In particular, available apparatus has not been satisfactor- `
ily adapted to treatment of tire making components of widely varying width.
A principal object of the present invention, there-fore, is the provision of apparatus capable of handling and treating by electron radiation tire components of diverse dimensions on an efficient production scale.
In accordance with one aspect of this invention there ` is provided in apparatus for treating a plurality of diverse tire making components including tire ply and gum stock by controlled exposure to high voltage electron beam radiation, including a source of said radiation, a walled chamber housing said source, an entry and an exit each having a labyrinthine passage between said enclosure and the sur-rounding space, conveyor means for controlling movement of ~ said components through said enclosure, let-off means for .~. . - :
3 delivering a running length of a selected one of said ` 30 components to said conveyor means, wind-up means for re-winding said running length as received from said conveyor ~e~n- after treatmene by naid radiation, the imQrovement :.

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~065795 wherein, said conveyor means comprises a plurality of rigid metallic bar-slat conveyors disposed in close parallel side-by-side array, a plurality of conveyor drives each drivingly connected respectively to only one of said conveyors and :~
operable to drive its respectively associated conveyor at a speed different from and independent of the speed of another of said conveyors, whereby each conveyor can travel through said enclosure at a speed proportioned to the radiation - .
dosage appropriate to a particular tire component carried thereon. ::.
To acquaint those skilled in the related arts with the -principles of the invention, a presently preferred embodiment .-.
illustrative of the best mode now contemplated for the - , , practice thereof,,will be described herein by and in ;~
connection with the attached drawings'wherein: :, ... .
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Fig. 1 is a schematic elevatlon view of apparatus according to the invention, the view being divided in two parts at a plane represented by the line A-A;
Fig 2 is a schematic plan view of the apparatus of Fig 1~ sim~larly divided by the plane represented by the line A-A;
Figs. 3~ 4~ and 5 are schematic diagrams of control circuits of the apparatus of Figs. 1 and 2.
The apparatus 10 shown synoptically in the drawings, particularly in Figs. 1 and 2~ includes a treatment chamber 12 housing three high-voltage electron beam acceierators, three groups~ L-l, L-2~ and L-3~ of stock letoffs~ a pair of conveyors C-l~ C-2~ and three groups W-l~ W-2~ and W-3~ of windups. m e two conveyors extend through the chamber from their receiving ends a associated with the letoffs to their delivery ends b associated with the windups. Labyrinthine passageways P-l~ P-2 provlde entry to and exit from the chamber 12 for the conveyors~ which carry~ and control~ the components to be treated in a horizontal plane 20 referred to herein as the treatment plane. For brevity, each of the high voltage electron beam accelerators is referred to herein as a Source S.
Three high-voltage electron beam radiation Sources S are mounted in the chamber 12 to direct energy onto the treatment plane 20. These Sources S are commercial units supplied by High Voltage Engineering Corporation~
of Burlington~ Maso. 01803 .
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The chamber 12 ~s of known constructlon~ being totally enclosed by shielding walls 22 and roof 2~ to protect personnel from the hazards known to be associated with such high voltage electron beam radiation.
Conveniently~ the chamber is located at least partly below grade~ that is, below the general floor or ground level, thus makinB use of the earth as a portion of the shielding. me chamber is equipped with an air-circulating blower (not shown) capable of scavenging ozone from the chamber. It is also desirable that the chamber be equipped with means for preventing human ~ -entry or presence during operation of one or more of the sources. Personnel access is provided by a shielded ~ -entryway 26 arranged to prevent the escape of radiation -~
to the space surrounding the chamber. A chilled water circulating system is provided to remove excess heat ~ .
developed by the radiation energy in the chamber and conveyors therein.
me labyrinthine passages P-l~P-2 provide a 20 vertically zig-zag path through which the conveyors travel and through which straight line radiation is prevented from escape. The passages are~for convenience in maintenance~ provided with roofs 28 constructed of heavy relnforced concrete sections which are removable.
In accordance with a feature of the inventlon~ the three identical Sources S are mounted in an identical manner~ about to be described, in the chamber 12. One of the Sources serves additionally as an in-place spare~

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: . - . ' providing for uninterrupted operation in the event of failure of one of the other Sources. Inasmuch as the Sources and their mountings are identical, the description of one will sufflce to describe each.
Each Source i3 provided with a mountlng ring 30 which is attached to the horizontal support plate 32 with its central radlatlon beam axls 34 extending normal to the treatment plane 20. The support plate is supported rotatably on a traverse plate 36 which is in turn mounted tr~an~atably on a pair of rails 38 which extend trans-versely of the conveyors. me arrangement iq such that ~ -the elongate window Sw Or the Source can be moved to any location laterally of the conveyors and can as well be rotated abcut its own vertical axis such that the length of the window Sw through which the electron beam 3 is pro~ected can be orlented at any angle with respect ; to the direction of travel of the conveyors, thereby ~l~ enabling the width of the beam scan to be matched to i the width of the tire component being treated.
me support plate 32 and the Source thereon are together rotated about the central axis 34 by a rotation drive~ Fig. 3~ mounted on the traverse plate 36~ a j``~ pinion 42 on the rotation drive motor 40 being drivingly in mesh with a gear 44 carrled by the support plate.
' 25 Means~ best seen in Fig. 4~ for moving the traverse ~I plate across the conveyors C-l~C-2 is provlded by a rack 46 and pinion 48 traverse drive including a travers-$-ing motor 50 by which the Source~ support plate, and .~ , ' .
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'.`'` ` , ' ~ ~ : -the traverse plate are moved as a unit across the conveyors.
Referrin~ also to Figs. 3 and 4~ a position encoder 60~ for transmitting the actual angular position of the window Sw~ relative to the direction of travel of the conveyor is mounted on the traverse plate and coupled,.by a pinion 61 and gear 62~ to be rotated proportionally by the support plate 32 as the latter is . rotated by the motor ~0. Signals emitted by the encoder ;
; 10 60 are transmitted to remote control means ln the panel `. 63 situated outside the chamber and specifically to a signal plus-minu~ adder 64 therein. In the adder~ the : -. signal from the encoder is compared with the angular position preset in the angle selector 66 and any di.fference .
between the actual and the preset positions generates a .~ ~
signal communicated to an amplifier 68. The output from the amplifier activates the drive ~0 to rotate the source .`~ to the preset angle.
In Fig. 4~ a position encoder 70 is connected~ by a pinion 71 engaeing the rack ~6~ to the traverse plate . . . .
and to the rails supporting it. The actual position of the traverse plate and the encoder 70 provides a signal fed back to ^ontrol means comprising a plus-minus adde.r 7~ in the panel 63~ and in which the actual position signal is compared to the traverse position preset in the selector 76. Any difference is communicated.by way of the amplifler 78 to the traversing drive motor 50 which moves the traverse plate and the Source to the preset position. me arrangement provides that an ,~ ,.. .

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1(~65795 operator outsi~e and remote from the chamber can position each source with respect to the particular component to be treated w~thout entering the chamber and can readily readjust such pcsitions to suit a change in dimensions from one to another such component Lock-out switches prevent the operator from changing from one operating mode to anothe~ without first inactivating the Sources ~.
The beam energy output per unit time and the dose rate~ to which the rate of travel of components carried . . , ~y the conveyor(s) is correlated can be measured by measuring the voltage induced in a wire placed in the beam path (Fig. 4) The wire is connected by appropriate electrical terminations to produce linear output and with means for displaying the measured voltage.
me two conveyors are provided with completely in-dependent drives which are conventional and identical -and serve to control the speed of each of the conveyors independently of the other. Re~erring to Fig. 5~ the drive arrangement for conveyor Cl is illustrated and described~ the numerals applied to the elements thereof being identically applied to like elements in the drive arrangement of conveyor C2 except for the addition of a prime ('). Conveyor Cl is provided with a drive motor 80 drivingly connected by way of a gear reduction 82 to the conveyor. The speed control circuit includes a con-- ventional tachometer 84 mechanically connected to the motor and a plus-minus adder 86 connected to receive the output from the tachometer. The adder is also connected : .

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to a speed cortrol potentiometer 88, and receives a signal representing a preset speed which in the adder 86 is compared with the signal received from the tachometer 84. The difference is communicated to 5 an amplifier ~0 and thence to the motor 80 to regulate -~
the speed thereof -In accordance with the invention, the drives for the respective conveyors are also provided with the capability of being driven synchronously as one conveyor.
In the speed control arrangement of conveyor C2 a selector switch 92 is interposed between the speed control preset potentiometer 88' and the adder 86'.
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When the two conveyors are being operated independently of one another selector switch9 ~ made between the potentiometer 88' and the adder 86' rendering the cir-cuit identicaI to that described in connection with conveyor C~. In order to lock the two conveyor drives into complete synchronism~ a digital or pulse tachometer 94~94' is mechanlcally connected respectively to each Or the drive motors 80~80'. me respective signals ..
emitted by the pulse tachometers are communicated separately to a digital comparator 96~ the output Or which is comnnhnicated~ by way of the selector switch 92 to the adder 86' in the control circuit Or conveynr C2.
In this way~ the driving speed of the motor 80' is slaved to the driving speed of the motor 80 of conveyor ~ . . .
Cl such that the two conveyors operate in complete synchronis~ particularly in their carrying surfaces .

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to the exter.t that they can be used as one single conveyor.
The letoffs~ L-l~ L-2, L-3~ and the windups~
W-l~ W-2~ W-3~ previously mentioned, are individually each well known devices. In the combination according to the invention, the letoffs are arranged in three groups. Group L-l provides a number of cantilevered shafts 110 each capable of accommodating a core 112 on which is wound a running length supply of a particular tire component to be treated in the apparatus. The arrangement provides that tire building components i,.......................................................................... .
such as chippers and chafers and like narrow strips can be placed on either one or both of the parallel conveyors, being paid off 'ndividually from the cores 112~ and in sufficient number to utilize the full width of one~ the other~ or both~ of the conveyors, as well as the available capacity of ~he eleetron beam source associated with sueh conveyor. In the windups W-l eaeh of the individual windups 113 receive and rewind one of the treated running lengths as recelved from the assoeiated conveyor after its treatment In the letoffs L-l~L-2 and the windups W-l,W-2~
provision is made for handlingcomponentsof widths not greater than the width of the individual conveyors. A com-ponentfrom either of the two letoffs L-2 can be supplied to either of the eonveyors, transported by the selected conveyor through the chamber for electron beam radiation ; treatment and rewound as received from the conveyor by a .

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selected one of the two windups W-2. Each of the letoffs L-2 and of the wlndups W-2 are provided wlth wheels 11~,115 providing means for readily disposing them in suitabie alignment wlth the selected conveyor.
In the letoff L-3 and in the windup W-3 a component of width greater than the width of either conveyor is unwound and transported by an overhead belt conveyor from which it ls applled to the surfaces of the two side-by-side conveyors operating in synchronism, is transported by the two conveyors Cl,C2, actlng as one~ through the chamber 12~ and is received from the dellvery ends of the conveyors and rewound by the wlndup W-3.
The apparatus comblnation described provides the particular advantage over apparatus known heretofore in .;....... . .
its capability of handling and treating a diverse variety of tire building components used in the manu-facture of tires on a virtually continuous basis~ whereas heretofore such treatment has been limited to a batch-type treatment. A unique advantage is that of having the capability of handling~ and treating~ in the same enclosure cham~er~ materials of different dimensions and~
therefore~ requiring different dosage rates both con-L ,~.
tinuously and concurrently~ coupled with the facility to handle and treat single componentsof sig-25 nificantly grsater width as a result of the provision of a plurality of conveyors operable either independently of one another or in locked synchronous conveying -relation.
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It will be understood that tire making components in sheet or strlp form will normally and preferably be associated Wit~l a cloth or equivalent sheet or strip as is customarily used in winding such components in rolls In the apparatus described such cloth sheet or strip preferably accompanies the component being treated from its supply roll on one of the letoffs on the conveyor through the treatment chamber, and is rewound with the component by the selected windup. ~;
In the disclosure~ the term component has been used to designate any of the sheet and strip materials used ln building tires~ and should be so understood in the claims. Examples of-such components which can be handled by the apparatus include but are not limited to gum stock~ liner~ ply stock~ chafer~ and chipper. ~uch components may or may not include cord~ fabric~ or wire reinforcing elements.
While certain representative embodiments and detalls have been shown for the purpose of illustrating the inventlon~ it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit or scope o~ the inven~lon.

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Claims (3)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In apparatus for treating a plurality of diverse tire making components including tire ply and gum stock by controlled exposure to high voltage electron beam radiation, including a source of said radiation, a walled chamber housing said source, an entry and an exit each having a labyrinthine passage between said enclosure and the surrounding space, conveyor means for controlling movement of said components through said enclosure, let-off means for delivering a running length of a selected one of said components to said conveyor means, wind-up means for rewinding said running length as received from said conveyor means after treatment by said radiation the improvement wherein, said conveyor means comprises a plurality of rigid metallic bar-slat conveyors disposed in close parallel side-by-side array, a plurality of conveyor drives each drivingly connected respectively to only one of said conveyors and operable to drive its respectively associated conveyor at a speed different from and independent of the speed of another of said conveyors, whereby each conveyor can travel through said enclosure at a speed proportioned to the radiation dosage appropriate to a particular tire component carried thereon.

2. Apparatus as claimed in Claim 1, comprising a master-slave speed control circuit interconnecting said plurality of conveyor drives and operable to lock said drives in synchronous speed relation one to another, wherein said let-off means includes a plurality of let-offs each disposed to supply a running length of un-radiated component to respective ones of said conveyors, and at least one let-off disposed to supply a running length of unradiated component wider than any one of said conveyors to a pair of said conveyors while the pair are moving synchronously.

3. Apparatus as claimed in Claim 1, further comprising a plurality of sources including the first mentioned source;
source mounting means respectively supporting each of said sources above and in operative relation to said conveyors;
said mounting means including a pair of spaced parallel rails bridging said plurality of conveyors, a traversing plate supported on said rails for movements across said conveyors, a support plate fixed rotatably on said traversing plate for rotation about a vertical axis and carrying one of said sources vertically thereon, control means situated without said chamber, drive means respectively connected to move said traversing plate and to rotate said support plate, and means responsive to said control means to energize said drive means whereby each said source can be positioned independently of others thereof relative to a selected one of said conveyors.