TIRE PLY JOINT CONFIGURATION

Abstract

A method of forming a layer of tire ply is disclosed. A first strip of ply is provided having a plurality of evenly spaced reinforcement cords, having a spacing S, and having a lateral end, wherein the last cord is spaced apart from strip end a distance X, wherein X is not equal to S. A second strip of ply is provided having a plurality of evenly spaced reinforcement cords, having a spacing S, and having a lateral end, wherein the last cord is spaced apart from strip end a distance Y, wherein Y is not equal to S. The lateral ends of the first and second strip are joined together in a lap joint. The first and second lateral ends are overlapped so that the spacing X preferrably does not overlap, but may partially overlap with the spacing Y.

Claims

1. A method of forming a layer of tire ply comprising the following steps: a. providing a first strip of ply having a plurality of evenly spaced reinforcement cords with a spacing S, and having a lateral end, wherein there is a distance X between the end of the first strip of ply and a reinforcement cord nearest the lateral end, wherein X is not equal to S; b. providing a second strip of ply having a plurality of evenly spaced reinforcement cords having a spacing S, wherein there is a distance Y between the end of the second strip of ply and a reinforcement cord nearest the lateral end, wherein Y is not equal to S; and c. joining the first and second lateral ends to form an overlapped portion, wherein only a single cord of the first strip overlaps with a single cord of the second strip.

2. The method of claim 1 wherein the spacing X does not overlap with the spacing Y.

3. The method of claim 1 wherein the spacing X is greater than the spacing Y.

4. The method of claim 1 wherein there are no cords a distance X from the lateral end of the first strip to the nearest reinforcement cord.

5. The method of claim 1 wherein there are no cords a distance Y from the lateral end of the second strip to the nearest reinforcement cord.

6. The method of claim 1 wherein X is 3.5S+3D, wherein S is the cord spacing of the first ply.

7. The method of claim 1 wherein Y is 1.5S+D.

8. The method of claim 1 wherein the X region of the lap joint has a single layer of cords.

9. The method of claim 1 wherein the Y region of the lap joint has a single layer of cords.

10. The method of claim 1 wherein only a single cord of the first strip lateral end is in parallel alignment with a single cord of the second strip lateral end.

11. A method of forming a layer of tire ply comprising the following steps: a. providing a first strip of ply having a plurality of evenly spaced reinforcement cords with a spacing S, and having a lateral end, wherein there is a distance X between the end of the first strip of ply and a reinforcement cord nearest the lateral end, wherein X is not equal to S; b. providing a second strip of ply having a plurality of evenly spaced reinforcement cords having a spacing S, wherein there is a distance Y between the end of the second strip of ply and a reinforcement cord nearest the lateral end, wherein Y is not equal to S; and c. joining the first and second lateral ends to form an overlapped portion forming a single layer of cords.

12. The method of claim 11 wherein in the overlapped portion of the lap joint so there are no cords of the first lateral end that overlap with cords of the second lateral end.

13. The method of claim 11 wherein the cords of the first strip lateral end are not in alignment with the cords of the second strip lateral end.

14. The method of claim 11 wherein the spacing X does not overlap with the spacing Y.

15. The method of claim 11 wherein the spacing X is greater than the spacing Y.

16. The method of claim 11 wherein there are no cords or broken cords a distance X from the lateral end of the first strip to the nearest reinforcement cord.

17. The method of claim 11 wherein there are no cords or broken cords a distance Y from the lateral end of the second strip to the nearest reinforcement cord.

18. The method of claim 11 wherein X is 3.5S+3D, wherein S is the cord spacing of the first ply.

19. The method of claim 11 wherein Y is 2.5S+2D.

20. The method of claim 11 wherein a X region of the lap joint has a single layer of cords, wherein the X region is defined by the X distance of the first layer and the X distance of the second layer.

21. The method of claim 11 wherein a Y region of the lap joint has a single layer of cords, wherein the Y region is defined by the Y distance of the first and second layer.

22. A pneumatic radial tire comprising: a carcass ply wound around each of a pair of bead cores, wherein the carcass ply is formed from a first strip of ply and a second strip of ply, wherein the first strip of ply has a plurality of evenly spaced reinforcement cords with a spacing S, and having a lateral end, wherein the last two cords at the lateral end are spaced apart a distance X, wherein X is not equal to S; wherein the second strip of ply has a plurality of evenly spaced reinforcement cords having a spacing S, and having a lateral end, wherein the last two cords at the lateral end are spaced apart a distance Y, wherein Y is not equal to S; wherein the first and second lateral ends are joined together in a lap joint wherein the spacing X does not overlap with the spacing Y.

23. The pneumatic radial tire of claim 21 wherein the cords of the first strip's lateral end are in parallel alignment with the cords of the second strip lateral end.

24. The pneumatic radial tire of claim 21 wherein the cords of the first strip lateral end are not in alignment with the cords of the second strip lateral end.

25. The pneumatic radial tire of claim 21 wherein a cord of the first strip lateral end is located between the last two cords of the second strip lateral end.

26. The pneumatic radial tire of claim 21 wherein the last cord of the first strip lateral end is located between the last two cords of the second strip lateral end.

27. The pneumatic radial tire of claim 21 wherein the last cord of the first strip lateral end is located adjacent the spacing Y of the second strip lateral end.

28. The pneumatic radial tire of claim 21 wherein the spacing X between the last cord and strip end is in the range of 1.5*S to 4*S.

29. The pneumatic radial tire of claim 21 wherein the spacing X between the last cord and strip end is equal to 2*S+D, wherein D is the cord diameter, and S is the cord spacing.

30. The pneumatic radial tire of claim 1 wherein the spacing Y between the last cord and strip end is equal to 2*C+D, wherein D is the cord diameter, and C is the cord spacing.

31. The pneumatic radial tire of claim 21 wherein the spacing X between the last cord and strip end is greater than 2*S+D, wherein D is the cord diameter, and S is the cord spacing.

32. The pneumatic radial tire of claim 21 wherein the spacing Y between the last cord and strip end is greater than 2*C+D, wherein D is the cord diameter, and C is the cord spacing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will be described by way of example and with reference to the accompanying drawings in which:

[0023] FIG. 1 is a schematic top view of a ply fabric undergoing shearing;

[0024] FIG. 2 is a schematic of the cut ply material shown spliced together on a tire drum;

[0025] FIG. 3 is a cross-sectional view of a conventional lap splice;

[0026] FIG. 4 is a cross-sectional view of a first embodiment of a lap joint formed from two ends of a ply which are joined together;

[0027] FIG. 5 is a cross-sectional view of a second embodiment of a lap joint formed from two ends of a ply which are joined together;

[0028] FIG. 6 is a cross-sectional view of a third embodiment of a lap joint formed from two ends of a ply which are joined together; and

[0029] FIG. 7 is a cross-sectional view of a portion of a tire in the bead area.

DETAILED DESCRIPTION OF THE INVENTION

[0030] A first embodiment of the present invention is shown in FIG. 4, which illustrates a lap joint 30. The inventive lap joints described herein are useful for joining together ends of reinforcement ply. As shown in FIG. 4, the lap joint is also useful for joining together end 21 of first ply strip 20 end 23 of a second ply strip 24. Each ply strip 20,24 is the same as strip 10 shown in FIG. 1 except as described below. The ply strips have a defined width W and a defined length L, wherein W and L are sized as required. Typically the length L is greater than the width W. The reinforcement cords in each strip are in parallel alignment along the length of the strip with the longitudinal axis of the strip as shown in FIG. 2. The first ply strips 20,24 are made from the process as shown in FIG. 1, wherein the lateral end 13 of a first strip is joined to the lateral end 12 of a second strip in the form of a lap joint 14, continuing the process to form a sheet of ply 16 as shown in FIG. 2. The lateral ends 12,13 are overlapped and joined together, so that the cords of each end are in parallel alignment as shown in FIG. 2. The lap joint 14 may also be used to join together the lateral ends of a sheet of ply.

[0031] As shown in FIG. 4, the lateral end 21 of the first ply strip 20 has a plurality of parallel cords 22 arranged along the length of the strip of the material. The cords 22 are in parallel alignment and are evenly spaced apart a distance S throughout the length of the first ply 20, except at the lateral end 21. The ply cords typically have an epi (ends per inch) in the range of 17-35, resulting in a range of S of about 0.001 to about 0.02 inch. At the lateral edge, the spacing X as shown between the outer edge 29 of the last cord 28 and the end 21 of the ply strip 20 is 3.5S+3D, wherein S is the cord spacing, and D is the cord diameter. However, X may be from 1.5S+D, 2.5S+2D, 3.5S+3D, or 4.5S +4D.

[0032] The second ply strip 24 has a plurality of parallel aligned cords 25 arranged transverse to the length of the sheet of the material. The cords 25 are evenly spaced apart a distance C through the length of the second ply, except at the lateral end 23. At the lateral end 23, the spacing Y between the edge of the last cord and the lateral end 23 is a distance Y. Y may be 0.5C, 1.5C+D, to 2.5C+2D, 3.5C+3D, or 4.5S+4D, wherein D is the cord diameter and C is the cord spacing. As shown in FIG. 4, the spacing X is not in parallel alignment with the spacing Y, and the spacing X does not overlap with the spacing Y. As shown in FIG. 4, only a single cord 28 of the first ply strip 20 overlaps in the Z direction and is in parallel alignment with a single cord 39 of ply strip 24. In the spacing X and Y, there is no cord present, and there is no partial cord or broken cord present. It is preferred that X is not equal to Y, and that X is greater than Y. It is preferred that cord spacing C of the second ply strip equals cord spacing S of the first ply strip. It is preferred that strip 20 with spacing X is in full contact with inner liner on drum

[0033] FIG. 5 illustrates a second embodiment 40 of a ply lap joint. The first ply strip 20 is the same as FIG. 4. The second ply strip 50 is different than the ply strip 24 of FIG. 4 as follows. The last cord 51 is spaced an interval G from the strip end 53. As shown in FIG. 5, the spacing X partially overlaps with the spacing G in the Z direction. Preferably the distance in the Z direction between cord edge 29 of cord 28 and cord edge 54 of cord 51 is in the range of 0.5S to S. As shown in FIG. 5, none of the cords of the first ply strip 20 overlap in the Z direction with cords 25 of the second ply strip 50. In the spacing X and G, there is no cord present, and there is no partial cord or broken cord present. It is preferred that X is not equal to G, and that X is greater than G. It is preferred that cord spacing C of the second ply strip equals cord spacing S of the first ply strip. It is preferred that strip 20 with spacing X is in full contact with inner liner on drum.

[0034] At the lateral edge of strip 20, the spacing X as shown between the outer edge 29 of the last cord 28 and the end 21 of the ply strip 20 is 3.5S+3D, wherein S is the cord spacing, and D is the cord diameter. However, X may be 1.5S+D, 2.5S+2D, 3.5S+3D, or 4.5S+4D. At the lateral edge of the second strip 50, the spacing G as shown between the outer edge 54 of the last cord 51 and the end 53 of the ply strip 50 is 2.5C+2D, wherein C is the cord spacing, and D is the cord diameter. However, G may also be 1.5S+D, 2.5S+2D, or 3.5S+3D. In the embodiment shown, due to the location of the X and G spacing, there is no double layer of cords in the lap joint.

[0035] FIG. 6 illustrates a third embodiment 60 with a slight overlap of the H and F spacing in the transverse direction. None of the cords in the first strip 62 overlap with the cords in the second strip 70 in the Z direction so that there is no double layer of cords in the lap joint. At the lateral edge of strip 62, the spacing H as shown between the outer edge 69 of the last cord 68 and the end 61 of the ply strip 62 is 0.5S, wherein S is the cord spacing. However, H may range from 0.25S to S. At the lateral edge of the second strip 70, the spacing F as shown between the outer edge 72 of the last cord 71 and the outermost end 73 of the ply strip 70 is 3.5C+4D, wherein C is the cord spacing, and D is the cord diameter. In the embodiment shown, due to the location of the H and F spacing, there is no overlap of cords in the Z direction, and thus no double layer of cords in the lap joint. It is preferred that the strip ends 61,73 are angled as shown. It is preferred that strip 70 is in full contact with drum.

[0036] The resulting lap joints described above have the strength of the prior art lap joint but without the disadvantage of the overlap of two functional cords.

[0037] All of the lap joints described above overlap a distance B as shown in FIG. 3. The distance B is typically 1-6 mm.

[0038] FIG. 7 illustrates a tire that has a layer of ply 5 wrapped around a bead 7. The ply is formed from a plurality of ply strips lap spliced together as shown in FIGS. 1-2 formed with a lap joints of any of the inventions described herein. The reinforcement cords are oriented in the radial direction of the tire. When the lap joint of FIGS. 4 through 7 are used, the overlap splice of the reinforcement cords align with the circumferential direction, transverse to the radial direction. The spacing X, Y, F,G, H, M likewise align in the transverse (circumferential) direction, perpendicular to the radial direction.

[0039] Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.