CA1091408A - Apparatus for positioning and curing a pre-shaped tire carcass - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Apparatus for positioning a partially shaped, uncured tire carcass and a tire curing bladder of a lower half-section of a vulcanization mold relative to one another, is disclosed. The apparatus includes the lower half-section of a vulcanization mold from which a inflatable, tire curing bladder extends axially upwardly, the bladder being axially and ra-dially expansible and contractible. A bladder-con-trolling piston rod is associated with the lower half-section and is used to axially elongate the bladder and thereby radially contract the latter. A circum-ferentially expansible-contractible tire carcass trans-porter is associated with the lower half-section and is effective to position a generally toroidally shaped.
uncured tire carcass concentrically around the bladder, with the lower bead of the tire in contact with the upper inner surface of the lower half-section. A down-wardly projecting cylinder and piston rod assembly is carried concentrically in and by the tire carcass trans-porter. The piston rod thereof when protracted is axially engageable with the aforementioned bladder-controlling piston rod to cause the latter to retract and thereby radially swell and fit the bladder into the interior of the uncured tire carcass. Steam injected into the bladder is used to assist the swelling of the latter, and subsequently to in part cure the tire carcass after it is released by the transporter and covered by an upper half-section of the mold.
This abstract is not to be taken either as a complete exposition or as a limitation of the present invention, the full nature and extent of the invention being discernible only by reference to and from the entire disclosure.

Description

1 09 1 4 ~ 8 ~ac ~ round of the Invention This invention relates generally to apparatus ~or properly positionlng and interfitting an uncured tire carcass and a tire curing bladder of a vulcaniza-tion mold relative to one another, and more particularlyto so positioning an uncured tire carcass which has been at least partially toroidally pre-shaped (for example, a radial ply carcass) prior to its positioning in the mold.
Vulcanization molds for curing vehicular pneu-matic tire carcasses ha~e long been known in the art.
One common type of vulcanization mold is ge~erally re-~erred to as a "clamshell" type mold which essentially comprises upper and lower mold half-sections and an upstanding curing bladder attached to and coaxial with the lower half-section of the mold. With such a mold, a tire carcass is prepared for curing by surrounding the mold bladder with the carcass and by placing one bead region thereof in contact with the interior of the lower half-section of the mold. The upper half-section of the mold is then lowered, initiating the conventional curing sequence.
In the case of conventional bias ply tires of the flat band type, the procedure involved is relatively direct. m e uncured tire carcass, which is generally cylindrical in con~iguration, is positioned around the generally cyl~ndrically shaped bladder, the axial height of which bladder hzs been preselectad to be generally the same as the axially extending height of the cylin-drically uncured tire carcass. The top half-section -1- *

914~8 o~ the "clamshell" may, thus, be simply lowered, s~mul-taneously forclng both the upper bead portion of the cylindrical carcass and the upper portion o~ the blad-der downwardly as the bladder is filled with pressurized steam. Such apparatus has long been acceptable to ex-pand the bladder smoothly and free of wrinkles into the raw tire carcass to enable the latter to be effec-tively cured.
me advent, however, of radial ply tlres has caused substantial dif~iculties with the aforementioned conventional "clamshell" system. These difficulties are due primarily to the fact that the bladder is generally cylindrical and conventional radial ply tires are usually pre-shaped in the form of a generally toroidal con~iguration prior to the vulcanization there-o~3 that is, while they still are raw tire carcasses.
As a result, it is dif~icult to ~it the cylindrical bladder into the interior of the toroidally shàped car-cass without wrinkling the bladder. It, thus, quickiy becomes clear that such conventional apparatus utilized for vulcanizing bias ply, flat belt, cylindrical raw tire carcasses is inappropriate ior vulcanizing pre-shaped tires, for example, heavy duty, steel-belted, radial ply tires.
The tire industry, in an effort to avoid the loss o~ its substantial capital investment in its "clamshell" molds used for curing conventional bias ply tire carcases of the flat band type, has attempted to modify such molds or the systems o~ whlch such molds are a portion so as to render them suitable ~or use in

-2-1~914(~8 curing pre-shaped tire carcasses, such as radial ply tire carcasses. One example of such a modified mold syætem is illustrated in U. S. Patent No. 2,997,738.
m is patent teaches the substitution of the aforemen-tioned bladder extending piston by a "double-acting plston"; that is to say, by two pistons connected to the lower mold portion, one piston serving the original purpose o~ axially extending the bladder so as to enable the positioning thereabout of the pre-shaped uncured tire carcass, and the second piston serving to draw the uppermost portion of the bladder downwardly until it is in alignmen~ with the uppermost bead of the tire carcass.
Although this structure appears to be operable for curing pre-shaped tire carcasses, it has certain drawbacks and disadvantages. Chief among such draw-backs is the fact that the "double-acting piston" cylinder iB sub~ect to leakage whereby water, the hydraulic medium used, seeps into the interior of the bladder and inter-feres with the steam in its effectiveness to uniforml~
vulcanize the tire carcass. Such leakage or seepage occurs principally when the "double-acting piston" is retracted to fit the bladder into the boroidally pre-shaped carcass.
Another disadvantage ls the cost and complexlty in modifying the existing "clamshell" molds by substitut-ing "double acting pistons" for the existing "single-acting pistons".

Summary of the Invention It is, there~ore, an ob~ect of the present ln-vention to provide an improved apparatus for positioning 3_ _4_ an at least partially pre-shaped, uncured tire car-cass around a tire curing blad~er by means of whlch the aforesaid drawbacks and disadvantages may be most e~flcaciously avoided.
It is a particular ob~ect of this invention to provide an improved carcass-positioning apparatus in which water leakage into the curing bladder is avoided.
It ls yet another ob~ect of this invention to provide such an improved carcass-positioning apparatus at a substantially lower cost than has heretofore been possible.
Generally speaking, the ob~ectives of the present lnvention are achieved by the provision of apparatus for positioning a partially toroidally pre-shaped~ uncured tlre carcass around a tire curing bladder, which ap-paratus comprises a lower vulcanization mold half-sec-tion, a tire curlng bladder connected to, and extend-ing axially of, the half-section, the bladder being lnflatable and, thus, both axially and radially ex-pansible and contractible, a tire carcass transporter for positioning a generally toroldally pre-shaped, un-cured tire carcass concentrically over and around the bladder, wlth the bladder in a cylindrlcal condition of greater axial extent than the carcass, and bladder-control means supported by the tire carcass transporter for urging the upper end of the bladder toward the lower mold half-section to fit the bladder into the tlre car-cass 80 that the bladder assumes a complementing sub-~tantially toroidal configuration for subsequent car-cass-curing purposes.

1~ ~L4~r~!3 -4a-More particularly, the present invention is em-bodied in an apparatus for inserting a bladder of a pneu-matic tire vulcanization mold into a pre-shaped partially toroidal raw tire carcass, which apparatus comprises:
transporter chuck means for detachably gripping a first bead of said carcass, said transporter chuck means in-cluding a circumferential array of similar and equidistantly spaced segments and control means for selectively increasing and decreasing the effective diametral condition of said cir-cumferential array of segments into and out of engagement with said first carcass bead;
a vulcanization mold section for vulcanizing said carcass into a final toroidal form, said mold section having means for engaging a second carcass bead, and said mold sec-tion including at its center an endwise movable first piston rcd having a free end portion concentrically arranged in said mold section and movable axially relative thereto;
an inflatable vulcanizing bladder capable of assuming both a cylindrical and a toroidal form surrounding said first piston rod with said free end portion being exterior of the bladder;
said first piston rod including circular plate means concentrically affixed to said free end portion thereof, said bladder having a circular edge secured to the periphery of said plate means in air-tight relation, and said bladder having an opposite circular edge secured to said mold sec-tion in air-tight relation;
single-acting means for protracting the first piston rod to cause the bladder to assume the cylindrical form from the toroidal form, the single acting means being exterior to the bladder; and ~ -4a-10914~B
-4b-power cylinder means affixed to said transporter chuck means concentrically within said circumferential array of segments, said power cylinder means including a second piston rod having a free end portion that is axially engage-able with the free end portion of the first piston rod and thereafter extensible to effect the retraction of the first piston rcd and initiate the transformation of the bladder from the cylindrical form to the toroidal form internally of the carcass.
Correspondingly, the present invention is also em-bodied in a method of inserting a bladder of a pneumatic tire vulcanization mold into a pre-shaped partially toroidal raw tire carcass, which method comprises the steps of:
(a) providing a mold half-section having at its center an endwise movable first piston rod which has a free end exterior of the bladder and is operatively associated with an inflatable vulcanization bladder that assumes a sub-stantially cylindrical form when said piston rod is pro-tracted and a substantially toroidal form when said piston rod is retracted;
(b) pushing one end portion of said first piston rod to protract the latter and cause said bladder to assume a substantially cylindrical form;
(c) surrounding said bladder with a pre-shaped, partially toroidal raw tire carcass having an axial extent substantially less than the axial extent of the cylindrical form of said bladder;
(d) filling said bladder with a heating medium; and (e) pushing against the free end portion of said first piston rod with a second piston rod to retract the first piston rod and cause said bladder to assume a substan-tially toroidal form internally of, and complementing the inner toroidal form of, said carcass.

-4b-10914~8 Brief Descri~tion of the Drawings m e foregoing and other ob~ects and features of the present invention will be more clearly understood from the following detailed description thereof when read in conJunction with the accompanying drawings, in which:
Fig. 1 is a perspect$ve view of the tire carcass transporter including the bladder control means of the invention;
Fig. 2 is a partially sectioned elevatlonal Yiew illustrating the lower half-section of a vulcani-~ation mold in its open position exposing the tire cur-ing bladder in a cylindrical condition, and the tire carcass transporter illustrated ln Fig. 1 gripping a partially toroidally pre-shaped uncured tire carcasæ;
and Figs. 3-6 are fragmented, sectional view of the ~pparatus in Fig. 2, illustrating the successive posi-tlons of the tire carcass transporter relative to the lower half-section of the mold in the course of posi-tioning the carcass around the bladder and upon the lower half-section.

Detailed Description of the Invention Referring now to the drawings, and more particu-larly to Fig. 1, the apparatus according to the present invention includes a tire carcass transporter or chuck generally denoted by the reference character 10. me chuck 10 may be in part of the type disclosed in U. S.
Patent No. 2,997,738, issued on August 29, 1961, or U. S. Patent ~o. 3,380,115, iscued on Aprll 30, 1968, 1~91408 or still yet otherwise conventlonal ln part.
In particular, the chuck 10 lncludes a circum-ferential array o~ similar, equidistantly spaced, segments 12 that at their respective lower lips 13 are arcuate in horizontal cross-section for coopera-tively gripping a bead 14 of a tire carcass 16 (Fig.
2). m e segments 12 each include a vertical stabiliz-~ng and reinforcing rib 18 that extends from a respec-tive lower bead-engaging flange 20 upwardly to a respec-tive cam-sensitive, follower housing 22 fixedly secured to each segment 12.
Each of the housings 22 is shiftable in a radial direction along a respective one of a plurality Or guide bars 24 that present a stationary radial array and proJect through the housings 22, respectively. The bars 24 are affixed to a central support 26 (Fig. 2) ln cantilevered fashion. To facilitate movement of the housings 22 along their respective bars 24, each Or the housings i8 provided internally with an upper and lower roller syætem (only the lower one of which is illustrated at 28) that embrace cooperatively respective ones o~ the ~ars 24.
Also mounted on the central support 26 is a cam plate 30 (Flg. 2) having spiral-like slots 32 associated, respectively, with the housings 22 via upstanding fol-lower pins 34 (Fig. 2) affixed to the housings 22, respectively. The cam plate 30 is rotatable relative to the central support 26 and driven, for example, by a crank 36 associated with a motorized unit, in part illustrated at 38.

.

10~1408 Illustrated i~ phantom ln Fig. 1, and in solld line ln Fig. 2, is a power c~linder or ~ack unlt 40 that is affixed to the central support æ and is ar-ranged concentrically within the circumferential array S o~ segments 12. The Jack unit 40 is provided with a protractable-retractable piston rod 42, the free end o~ which is axially engageable with the ~ree end 44 of a piston rod 46 associated with the lower half-section 48 of a tire carcass vulcanization mold (the upper half-section of the mold is not shown, but is understood tobe complemental to the lower hal~-section in a conven-tional manner). The ~ack unit 40 may be of the "single-acting" variety in that it is only capable of itsel~
protracting the piston rod 42, or lt may be o~ the "double-acting" variety in that it can itself protract and retract the plston rod 42.
As shown in Fig. 2, the lower half-section 48 ~ncludes an annular concavity 50 of semi-toroidal con-riguration that is formed in an annular section 52.
ProJecting through a central opening 54 in the section 52 is a sleeve 56 that is ~ixedly secured to the sec-tlon 52 in a conventional manner, for example, at 58.
Secured fixedly to the sleeve 56, internally thereof, is one end of a tube 60 that communicateæ at its op-posite end with a power cylinder or Jack ~not shown).Extending through the tube 60, and movable relative thereto, is the piston rod 46 that is associated with the latter said ~ack (not shown). m e piston rod 46 1~ 80 controlled by the latter said ~ack that it, the piston rod 46, is only protractable by the ~ack and is not retractable by the latter. As such, the piston rod 46 is controlled by a "single-acting" ~ack and not by a "double-acting" ~ack that is capable of itself protracting and retracting its associated piston rod.
Affixed to the upper end 44 of the piston rod 46 is a plate 62. me periphery of the plate 62 secures in air-tight relation a circular edge 64 of a conven-tional cylindrical bladder 66 used for vulcanizing tire carcasses. me opposite circular edge 68 of the bladder 66 is ln air-tight relation affixed to the sleeve 56 in a conventional manner.
Formed in the sleeve 56 is one or more channels 70 that communicate at one end with the in~erior of the bladder 66 and at the opposite end with respective con-duits 72 utilized for directing the flow of, for example, pressurized steam into and out of the bladder 66 to ef-rect carcass vulcanization.
In operation, the tire carcass transporter or chuck 10 is initially out of axial alignment with, and remote from, the lower mold half-section 48. As such, the segments 12 o~ the chuc~ 10 can be moved inwardly so as to reduce the diameter of the circumferential ar-ray they form, via the cam plate 30, to a small enough condition for penetrating a bead 14 of a pneumatic tire carcass, for example, the carcass 16. m e cam plate 30 can then be turned to expand the circumferential array of segments 12 so that the lower lips 13 can appro-priately grip the bead 14 of the carcass 16. m e chuck 10 can then be raised, by conventional means not shown, and moved proximate to, and into axial alignment with, g the lower mold half-section 48. Such a condition is illustrated ln Fig. 2.
At such tlme, the piston rod 46 can be protracted upwardly so as to cause the bladder 66 to assume a sub-stantially cylindrical condition small enough for the lower bead 14A of the carcass 16 to be mo~ed into sur-rounding relation therewith, via the chuck 10. In order to facilitate movement of the carcass 16 into surround-ing relation with the bladder 66, a slight vacuum is created in the bladder 66 to cause the cylindrical wall thereof to move inwardly slightly toward the piston rod 46. Such a vacuum can be created by conventional means associated in a conventional manner with the channels 70 and conduits 72, or by any other means of conventional nature not shown.
The chuck 10 can then be lowered, as illustrated ln Fig. 3, so that the lower bead 14A of the carcass 16 engages the section 52 of the lower mold half-section 48.
The vacuum in the bladder 66 is then released, and steam under pressure is introduced into the bladder 66. m e piston rod 42 of the ~ack 40 associated with the chuck 10 is then protracted to axially engage and cause the retraction of the piston rod 46 assoclated with the bladder 66.
Aæ the piston rod 46 retracts, the bladder 66, filled with pressurized steam, begins to gradually con-form to the internal surface configuration of the car-cass 16 so that it, the bladder 66, also assumes a some-what toroidal configuration. me gradual conformatlon of the bladder 66 to the interior of the carcass 16 is 10914~8 shown successively ln ~igs..4-6.
Although not illustrated, an upper mold half-section of çonventional design can be lowered onto the lower mold half-section 48 to effect further deformation of the bladder 66 and carcass 16 into a final toroidal shape for vulcanization. Of course, the chuck 10 is removed from the vicinity of the lower mold halr-sec-tion 48 before the latter is closed by its associated upper mold half-section (not shown).
The significance o~ the present invention lies ln the arrangement of the ~ack 40 and its associated protractable-retractable piston rod 42 within the cir-cumferential array of segments 12 of the chuck 10. As such, the piston rod 42 iæ axially engageable with the piston rod 46 associated wlth the lower mold hal~-sec-tion to effect the retraction of the piston rod 46 in-dependently of the ~ack (not shown) associated with the plston rod 46. As a result, the prime mover (the piston rod 42) for causing the bladder 66 to con~orm to the in-terior a the carcass 16 is isolated from the interior of the bladder 66 and cannot be the cause of leakage of its hydraulic or pneumatic medium into the bladder 66, which would otherwise interfere with the steam in the bladder 66 to uniformly vulcanize the carcass 16.
Th1s is to be d~stinguished ~rom the conventional association of the piston rod 46 with a "double-acting"
Jack capable of both protracting and retracting it. If such a conventional ~ack were employed, the hydraulic medium (usually water) associated with it would run along the length of the piston rod 46 and seep lnto the bladder ~091408 66 when the piston rod 46 is retracted. m e present invention obvlates this possibillty since retraction of the plston rod 46 is a function of the protraction of the piston rod 42 which is isolated therefrom and, thus, from the bladder 66.
~ aving thus set forth the nature of the present invention, it will be understood that the foregoing description of a preferred e~bodiment of the present invention is ~or purposes of illustration only, and that the various structural and operatlonal features and relationships herein disclosed are susceptible to a number of modificiations and chan~es none of which entails any departure from the spirit and scope of the present invention as defined in the hereto appended claims.

Claims (13)

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

1. Apparatus for inserting a bladder of a pneumatic tire vulcanization mold into a pre-shaped partially toroidal raw tire carcass, said apparatus comprising:
transporter chuck means for detachably gripping a first bead of said carcass, said transporter chuck means including a circumferential array of similar and equidis-tantly spaced segments and control means for selectively increasing and decreasing the effective diametral condition of said circumferential array of segments into and out of engagement with said first carcass bead;
a vulcanization mold section for vulcanizing said carcass into a final toroidal form, said mold section hav-ing means for engaging a second carcass bead, and said mold section including at its center an endwise movable first piston rod having a free end portion concentrically arranged in said mold section and movable axially relative thereto;
an inflatable vulcanizing bladder capable of assuming both a cylindrical and a toroidal form surrounding said first piston rod with said free end portion being exterior of the bladder;
said first piston rod including circular plate means concentrically affixed to said free end portion thereof, said bladder having a circular edge secured to the periphery of said plate means in air-tight relation, and said bladder having an opposite circular edge secured to said mold sec-tion in air-tight relation;

single-acting means for protracting the first piston rod to cause the bladder to assume the cylindrical form from the toroidal form, the single acting means being ex-terior to the bladder;
power cylinder means affixed to said transporter chuck means concentrically within said circumferential array of segments, said power cylinder means including a second piston rod having a free end portion that is axially engage-able with the free end portion of the first piston rod and thereafter extensible to effect the retraction of the first piston rod and initiate the transformation of the bladder from the cylindrical form to the toroidal form internally of the carcass.

2. Apparatus as claimed in claim 1 wherein the segments surround the bladder and control the radial ex-pansion of the bladder.

3. Apparatus as claimed in claim 1, wherein said control means of said chuck means includes a rotatable member having cam slots operatively associated with said segments, respectively, for moving the latter select-ively.

4. Apparatus as claimed in claim 3, wherein said chuck means includes a radial array of cantilevered members, each of said segments including housing means affixed to one end thereof respectively and loosely surrounding respective ones of said cantilevered members for displace-ment relative to the latter.

5. Apparatus as claimed in claim 4, wherein each of said housings includes respective follower means operatively associated with a corresponding one of said cam slots.

6. Apparatus as claimed in claim 1, wherein said power cylinder means is affixed to said chuck means such that said second piston rod thereof con-fronts and is concentric with a carcass bead gripped by said segments.

7. Apparatus as claimed in claim 1, wherein said piston rod of said second power cylinder means has a stroke sufficient to effect the retraction of said first piston rod associated with said mold section over an axial extent that is sufficient to transform said bladder from a cylindrical configuration to a toroidal configuration fully complementing the internal configuration of said carcass.

8. Apparatus as claimed in claim 1, wherein said power cylinder means is pneumatically actuated.

9. Apparatus as claimed in claim 1, wherein said power cylinder means is hydraulically actuated.

10. Apparatus as claimed in claim 1, including suction means operatively associated with the interior of said bladder.

11. Apparatus as claimed in claim 1, wherein said power cylinder means is a single-acting jack.

12. Apparatus as claimed in claim 1, wherein said power cylinder means is a double-acting jack.

13. A method of inserting a bladder of a pneumatic tire vulcanization mold into a pre-shaped, partially toroid-al, raw tire carcass, said method comprising the steps of:
(a) providing a mold half-section having at its center an endwise movable first piston rod which has a free end exterior of the bladder and is operatively associ-ated with an inflatable vulcanization bladder that assumes a substantially cylindrical form when said piston rod is protracted and a substantially toroidal form when said pis-ton rod is retracted;
(b) pushing one end portion of said first piston rod to protract the latter and cause said bladder to assume a substantially cylindrical form;
(c) surrounding said bladder with a pre-shaped, partially toroidal, raw tire carcass having an axial ex-tent substantially less than the axial extent of the cylindrical form of said bladder;
(d) filling said bladder with a heating medium; and (e) pushing against the free end portion of said first piston rod with a second piston rod to retract the first piston rod and cause said bladder to assume a sub-stantially toroidal form internally of, and complementing the inner toroidal form of, said carcass.