Split ply tires and bead area monocomponents

Abstract

An intermediate article of manufacture formed as a first stage bead area subassembly for a split ply pneumatic tire carcass is disclosed. The bead area subassembly has an annular bead core; a bead apex; a ply strip; and preferably a sidewall affixed to the ply strip. The subassembly is formed into a disk-shaped bead area monocomponent. The ply strip is wrapped about the bead core and the apex to form a ply turnup and both the ply strip and the ply turnup extend radially outwardly from the bead core. The bead area subassembly when formed into the disk-shaped bead area monocomponent is placed on an annular holder device.

Claims

1. A method of forming an article of manufacture formed as a first stage bead area subassembly for a split ply pneumatic tire carcass, the method comprising the steps of: providing a first stage building drum having a single inflatable turnup bladder, one set of bead locks and one expandable set of drum center segments and a separate molded hub for delivering a bead core and removing and storing the finished subassembly; applying a gum chafer strip cylindrically onto the inflatable turnup bladder adjacent the one expandable set of drum center segments; applying a ply strip cylindrically over the gum chafer strip; delivering the bead core held by separate molded hub and positioning the bead core overlaying the gum chafer strip and the ply strip over the single set of bead locks; clamping the bead core and removing the molded hub; expanding the set of expandable center segments turning radially upwardly a portion of the ply strip; applying a bead apex against the bead core and the turned up portion of the ply strip; inflating the turnup bladder moving a remaining portion of the ply strip about the bead core and bead apex and ply strip turnup to form the first stage bead area subassembly for a split ply tire carcass configured as a radially extending disk-shaped bead area monocomponent.

2. The method of forming an article of manufacture formed as a first stage bead area subassembly for a split ply pneumatic tire carcass of claim 1 further comprises: applying a sidewall against the ply strip of the bead area monocomponent to complete the first stage bead area subassembly.

3. The method forming an article of manufacture formed as a first stage bead area subassembly for a split ply pneumatic tire carcass of claim 1 wherein the apex is applied from a gear pump and extruded onto the bead core and turnup.

4. The method forming an article of manufacture formed as a first stage bead area subassembly for a split ply pneumatic tire carcass of claim 2 wherein the sidewall is applied from a gear pump and extruded onto the ply strip.

5. The method forming an article of manufacture formed as a first stage bead area subassembly for a split ply pneumatic tire carcass of claim 2 further comprises the steps of: moving the molded hub over the first stage building drum to attach the first stage bead area subassembly configured as the radially extending disk-shaped bead area monocomponent; removing the molded hub with the attached first stage bead area subassembly configured as the radially extending disk-shaped bead area monocomponent from the first stage building drum.

6. The method forming an article of manufacture formed as a first stage bead area subassembly for a split ply pneumatic tire carcass of claim 5 further comprises the step of: stacking the molded hub with the attached first stage bead area subassembly configured as the radially extending disk-shaped bead area monocomponent onto a stack for storage and latter assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

(2) FIGS. 1-5 are partial cut-away perspective views of a simplified first stage building drum for building the disk-shaped bead area monocomponent of the present invention.

(3) FIG. 1 shows the gum chafer strip positioned under the ply strip with the bead core affixed to a molded holder being positioned in place as shown.

(4) FIG. 2 shows the bead holder withdrawn and removed from the building drum.

(5) FIG. 2A shows the exemplary bead lock fingers added to the view of the building drum showing how the bead core is locked onto the building drum.

(6) FIG. 3 shows the radially expandable drum center segments expanded causing the turnup to fold radially upwardly and an apex strip being extruded onto the bead core and against the turnup.

(7) FIG. 4 is a schematic view of the turnup bladder being inflated causing the ply strip to be oriented radially outwardly thus shaping the bead area monocomponent into a disk-shape.

(8) FIG. 5 is a schematic view of a sidewall being formed against the ply strip completing the disk-shaped bead area monocomponent.

(9) FIG. 6 is a cross sectional view of the disk-shaped monocomponent made according to the present invention.

(10) FIG. 7 is a partial view of the molded hub shown holding a bead core.

(11) FIG. 8 shows a stack of molded hubs.

(12) FIG. 9 shows how the disk-shaped monocomponent can be held by the mold hub.

(13) FIG. 10 shows the molded hub placing the disk-shaped monocomponent onto a second stage building machine.

(14) FIG. 11 is the schematic cross sectional view of a split ply carcass having a pair of the disk-shaped monocomponents of the present invention.

(15) FIG. 12A is a schematic view of an unvulcanized split ply casing with belt reinforcement applied onto the carcass.

(16) FIG. 12B is the split ply tire schematic with a tread added to the casing to complete the assembly.

DETAILED DESCRIPTION OF THE INVENTION

(17) With reference to FIG. 6, a cross sectional view of the disk-shaped bead area monocomponent made according to the present invention is illustrated. As shown, the monocomponent 10 has a bead core 20. The bead core 20 is made of substantially inextensible wires wrapped around to form an annular ring. Directly above the bead core 20 is an elastomeric apex 30. The apex 30, shown in a somewhat triangular form, is positioned and provides an elastomeric spacer between the ply strip 12 and the ply turnups 14 as illustrated. The ply turnup 14 as shown extends to a turnup end 14A which is stitched directly onto the working portion or outside ply portion 12A of the ply strip 12. The ply strip 12 wrapping about the bead core 20 as shown provides the opportunity to have an inside ply ending or turnup 14 relative to the bead core 20. On the outside of the ply strip 12 is the working portion of the ply which extends to a radially outer end 13 as illustrated and affixed to the outer surface of the ply strip 12 is a rubber or elastomeric sidewall portion 40 which extends along a portion of the outside of the ply strip 12 downward to the gum chafer 11. The gum chafer 11 is applied to the ply strip 12 and both wrap directly under the bead core 20 up and around the bead as illustrated. The gum chafer 11 provides a durable rubber element to prevent rim chaffing when mounted on a tire rim. These components as shown are assembled and provided as a simple relatively flat disk-shaped bead area monocomponent for use in making a split ply carcass for a split ply tire assembly.

(18) With reference to FIGS. 10 and 11 a schematic cross sectional view of a split ply carcass is shown using a pair of the disk-shaped monocomponents 10 of the present invention. The pair of disk-shaped monocomponents 10 preferably is positioned on each side of a second stage building drum 90 on a radially expandable mandrel 92 overlying a substantially air impervious inner liner 15 and the radially outer ply endings 13 are covered by a reinforcement crown ply 16. As shown the split plies 12 preferably are reinforced by cords 7, the cords 7 can be textile, rayon, polyester, aramid, or alternatively can be made out of steel if so desired. When so produced the monocomponent 10 is positioned such that the turnup 14 is provided axially inward of the bead core 20 in such a fashion that the working ply portion 12A of the ply strip 12 is on the axially outer side of the tire relative to the bead cores 20 and extends upward to the crown ply. The positioned crown ply 16 is stitched directly onto the ends of the monocomponent 10 at the ply strip ending 13 in such a fashion that the crown ply 16 extends from both ply strips 12 to form the split ply carcass structure as shown.

(19) Once the carcass is assembled as shown in FIG. 11 using the pair of disk-shaped monocomponents 10 of the present invention, it can be formed into a split ply casing with the addition of belt reinforcement plies 17, 18 applied onto the carcass overlaying the crown ply 16 and the ends 13 of each of the ply strips 12. This is shown in FIG. 12A. With reference to FIG. 12B once the belt reinforcement plies 17, 18 have been added to form a casing, the entire assembly can be completed by the application of a tread 19 applied over the belt reinforcements 17, 18 and extending to the sidewall 40 of the monocomponent 10 as illustrated. As can be easily appreciated, the bead area monocomponent 10 being formed in a flat disk-shape makes it quite convenient for producing a tire such that inside turnups 14 can be provided on a split ply carcass in such a way that all of the sidewall components including the bead 20, gum chafer 11, sidewall 40, apex 30 and the sidewall split ply strip 12 can be provided as a single unitary component. By having one of the monocomponents 10 rotated 180 degrees relative to the other enables the opposite side of the tire to be built such that an inside turnup is also achieved on the opposite side of the tire casing using the same identical monocomponent 10.

(20) One of the advantages of the disk-shaped bead area monocomponent 10 as illustrated is that a variety of tire sizes can be made using a single component structure. This is possible because the width of the tire can be changed by providing a longer or wider width crown ply 16 such that the beads can be moved outwardly and wider tires can be produced. Alternatively, a narrower crown ply will produce a narrower tire assuming the sidewalls all have the same length. Alternatively, the tire can be produced even with different sidewall heights using the same components simply by increasing or reducing the amount of overlap between the crown ply and the sidewall ply if so desired. While this is normally not preferred due to wastage, in some cases where an over extension of overlap material is used it is possible to make tires of varying widths and sidewall dimensions simply by varying the amount of tread rubber that is applied adjacent to the sidewall. In such a fashion that an upper portion of the tread may extend downward a litter farther than normal and this would enable the assembly to produce a variety of sizes of both different widths and different heights. It is believed preferable that only tires of different widths be constructed using the same sidewall lengths in that specifically designed tires having additional sidewall rubber can be applied for taller tires if so needed or if a lower aspect ratio shorter tire sidewall is needed less sidewall rubber can be applied. In this fashion it is possible that the sidewall rubber can be applied at the second stage and that the monocomponent 10 could be made without including the sidewall rubber, in that case tires of any size could be produced using a single monocomponent 10 in a disk-shape as illustrated. In that case the sidewall rubber would be applied as the second stage of the building process. While this is not the preferred embodiment, the preferred embodiment method of assembly includes the use of the sidewall 40 as part of the first stage building which will be described as follows in reference to FIGS. 1-5.

(21) In order to make the disk-shaped monocomponent 10 of the present invention, it is important to use a modified or simplified first stage building drum 50. The method of assembly is shown in FIGS. 1-5 wherein the disk-shaped bead area monocomponent 10 of the present invention is shown being assembled at a modified first stage building drum 50. A unique feature of this first stage assembly is that the building drum 50 is only basically half of a normal or conventional first stage building drum 50 in that it has only one set of drum center segments 51 that are radially expandable and has a single turnup bag or bladder 52 attached to the first stage building drum 50 and one set of bead locks 54. The bead locks are not shown in FIG. 1, however are shown in FIG. 2A. The bead locks 54 are expandable and retractable to provide a way of securing the bead 20 when the bead core 20 is positioned over the first stage building drum 50. As shown, the bead core 20 is delivered over the turnup bladder 52 as shown in FIG. 1 by means of a molded hub 2, the molded hub 2 can be moved robotically over the bead lock area as shown in FIG. 2A. When positioned the molded hub 2 can hold the bead core 20 which is made substantially of steel wires by using a magnetic element within the bead holder 2 or alternatively can use pins to support the bead core 20. During assembly, the bead core 20 is moved into position over both a previously applied cylindrical gum strip 11 which is covered by a ply strip 12 has been cylindrically applied. As shown in FIG. 1, the gum strip 11 is positioned somewhat centrally under the position of the bead core 20 and the ply strip 12 is positioned such that a portion 14 of the ply strip 12 extends over the radially expandable drum center segment 51 and another portion 13 of the ply strip 12 extends over the inflatable bladder 52 as shown in FIG. 1. The portion 14 of the ply strip 12 that extends over the radially expandable center segments 51 forms a ply turnup 14 as will be discussed later. Once the bead holder 2 has moved the bead core 20 into position over the cylindrically formed components 11 and 12 already applied to the first stage building drum 50, as shown in FIG. 2A, the bead locks 54 can move out radially locking the bead core 20 into position. At that point, the bead holder 2 is removed. Once the bead core 20 is locked in place, the radially expandable center segments 51 are radially moved outwardly as shown in FIG. 3, when this occurs the turnup 14 is formed oriented vertically as illustrated extending out radially from the bead core 20. As shown in FIG. 3, a gear pump 70 with a nozzle 72 is shown positioned feeding elastomeric material to form a triangular shaped bead apex 30 directly onto the bead core 20 and against the turnup 14. Alternatively, this bead apex 30 can be pre-formed as a strip and simply positioned onto the bead core 20 against the turnup 14 if so desired without applying it in this hot form method shown using the gear pump 70 and extruder. This assembly has now created the ply strip 12 with a gum strip 11 and an apex 30 and a bead core 20. In FIG. 4 the turnup bag or bladder 52 is inflated and the remaining portion of the ply strip 12 is pushed against the bead core 20 and the apex 30 and extends radially outwardly as illustrated. When this occurs, the bead area monocomponent 10 assembly is virtually complete as a single piece disk-shaped bead area monocomponent 10. As shown in FIG. 5, additionally a sidewall rubber can be applied to this disk-shaped bead area monocomponent 10 as shown. In this case a gear pump 80 with an extruder nozzle 82 is shown positioned in such a fashion to deliver sidewall rubber 40 along the side of a portion of the ply strip 12. This hot formed sidewall strip 40 is then adhered directly onto the monocomponent 10 as illustrated. Once this assembly is completed the monocomponent 10 can be removed from the first stage building drum 50.

(22) To remove this completed assembly of the monocomponent 10, the molded hub 2 is brought back into position over the first stage building drum 50, bead locks 54 are retracted and the bead released and the molded hub 2 can magnetically or by the use of pins grab the monocomponent 10 in such a fashion that it can be withdrawn over the first stage building drum 50 and held as illustrated in FIG. 9.

(23) As shown in FIGS. 7 and 8, the molded hub 2 is shown in a cross sectional view holding onto a bead core 20. The bead core 20 can be held magnetically or by the use of pins that will center the bead core 20 relative to the molded hub 2. The molded hub 2 acts as a bead holder in the first stage building process. As shown it has an external groove 3 that can register on centering the yokes on building machines. These centering yokes are fundamentally robotic pieces of equipment that move the molded hub 2 into position over the bead locks 54. Although, not illustrated, these centering yokes are common features commonly used on first stage building machines. As shown by providing the molded hubs 2 with a projecting portion 5 on one side of the external groove 3 and a recess 4 on the opposite side, it is possible to stack the molded hubs 2 in such a fashion that they can hold a plurality of bead cores 20 in a stacked fashion as shown in FIG. 8. This stacking of the bead cores 20 enables a plurality of bead cores 20 to be in position ready to be brought to the modified first stage building machine 50.

(24) Once the monocomponent 10 is completed, the molding hub 2 without bead cores 20 can be used as a storage device for the monocomponents 10, as such when the monocomponent 10 is completed the molded hub 2 is put back over the first stage building machine 50 and it can capture the monocomponent 10 either magnetically or with the use of pins and bring a monocomponent 10 off of a first stage building machine 50 where it can be stacked for storage. These monocomponents 10 provide all the sidewall features necessary to build a split ply pneumatic tire as previously discussed. Once completed, these flat disk-shaped monocomponents 10 can be stored and brought into production to make a finished product as required.

(25) While split tires are known, and the use of split ply tires with inside turnups are also known in the prior art, it is believed that such a manufacture of disk-shaped monocomponents has never been attempted. This provision of making the monocomponent into a disk-shape such that it is suitable for use in the second stage building means that all the components necessary to build the sidewall of a tire including the gum chafer 11, the bead core 20, the apex 30, the ply turnup 14, sidewall ply 12 and sidewall rubber 40 are all pre-assembled into a single monocomponent 10. Accordingly while bringing this single monocomponent 10 to a second stage building machine as previously discussed, the only steps left are to provide a center crown ply 16 that extends between two opposing monocomponents 10 with the ends 12 stitched and this can be done in a radially and toroidaly expanded condition such that the ply strips are stitched about an expandable toroidal mandrel and as stitched, are stitched in a fashion most closely replicating the finished product. Once this is accomplished the belt reinforcing structure 17, 18 can be overlayed over the crown center ply 16 and the stitched ends 13 of the ply strips 12 such that a secure assembled split ply casing has been constructed. Once that is accomplished, the tread 19 can be applied onto the casing and the tread 19 has lateral ends that will extend to the sidewall rubber 40 on each side of the tire completing the split ply unvulcanized green tire ready for molding. This greatly simplifies the production steps required to produce such a tire and as such can reduce the cost dramatically in the production of such a tire. The advantage is that the turnups 14 are inside and that both sides of the tire are made from two identical components, one being flipped 180 degrees relative to the other to enable the ply turnups 14 to be positioned inwardly on both sides of the tire 100. Once this is accomplished, these components can make a tire 100 with improved bead durability and handling characteristics. While shown the split ply disk-shaped monocomponent 10 is shown utilizing a radial ply strip 12 reinforced by radially extending ply cords 7 which can be textile, synthetic, steel or any other material used in the construction of carcass plies. Alternatively, other angular orientations can be attempted in the sidewall area of the split ply 12 if so desired. Similarly while the tire 100 is shown as a single ply reinforcement, it is possible to make a bias tire in this fashion by simply providing two layers of ply strips 12 if so desired. In doing so the two layers of ply strips could have opposing angles, however they would be provided in the first stage building as shown in multiple layers as shown in FIG. 1, but with two layers. While not illustrated, it is important to understand that a bias tire could be made in this fashion. While this is not preferred due to the added cost, it is important to note that more than one ply strip can be added if more reinforcement is needed in the sidewall area. This is important in that elastomeric material could be positioned between the two ply strips to provide a limited runflat capability if so desired. These and other features are possible with the use of the disk-shaped monocomponent 10 as described and shown herein.

(26) The invention has been described with reference to a best mode. Obviously, modifications and alterations will occur to others upon reading and understanding of this specification. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof.