GB1586317A

GB1586317A - Pneumatic tyre with an interrupted defelctor ring

Info

Publication number: GB1586317A
Application number: GB1136478A
Authority: GB
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1977-07-07
Filing date: 1978-03-22
Publication date: 1981-03-18
Also published as: FR2396662A1

Description

(54) PNEUMATIC TIRE WITH AN INTERRUPTED DEFLECTOR RING (71) We, CATERPILLAR TRACTOR CO., a corporation organized and existing under the laws of the State of California, United States of America, of 100 N.E. Adams Street, Peoria, Illinois, 61629, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to tube tires, for example, tires utilized on earthmoving vehicles, and more specifically, to a tire incorporating the tread bars into the sidewall construction allowing flexure thereof while protecting the sidewall by providing an interrupted deflector ring thereabout.

Tires utilized on earthworking machines are subject to damage from the ground conditions prevalent in the environment in which such machines are operated. For example, in road construction, earthmoving machines commonly pass over rock fill and the like. Such rock fill or other rubble has an inherent tendency to cut and damage heavy equipment tires. Generally speaking, cuts in the treads of the tire, although shortening the working life of the tire to a certain extent, have little immediate impact on the operation of the vehicle. On the other hand, a rock cut or the like in the sidewall of a tire where flexure is normal can cause premature tire failure, sometimes to the extent of an immediate failure.

Recently, earthmoving tires have been developed which utilize the tube tire principle.

A tube tire has a radial cross-section forming an oval so that the conventional rim with a bead retainer and the bead of the tube are not necessary for inflation of ;the tire. One characteristic of the beadless tube tire is that the flexure point may be placed in closer proximity to the inner wall adjacent the vehicle wheel. In the more familiar beaded tire, the flexure point is of necessity placed further out on the tire sidewall as motion or -flexure in the vicinity of the bead is detrimental to tire life and may, in fact, cause bead failure with subsequent rapid deflation or blow-out. The ability to place the flexure point closer to the tire rim allows for a lower profile tire. Nevertheless, the flexure point is the critical point in the tire in that, generally, it is the thinnest exposed portion of any tire. Accordingly, it is important to provide protection to this flexure point, particularly in earthworking equipment vehicle tires.

According to the invention a pneumatic tube tire comprises means for mounting the tire on a wheel; a pair of first sidewalls radially outwardly extending axially divergingly from the mounting means; a pair of second sidewalls each integral with and radially outwardly extending axially convergingly from a respective one of the first sidewalls; and an annular tread wall integral with and connecting the pair of second sidewalls, the tire thereby having a generally semi-circular sidewall portion between the tread wall and the mounting means, the annular tread wall including a plurality of tread bars, each tread bar extending radially inwardly along one of the second sidewalls towards the first sidewall to form a buttress along the second sidewall to form thereby an interrupted deflector ring.

One example of a tube tire according to the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a plan view of a portion of the tire's tread; and, Figure 2 is a cross-sectional view of the tire taken on the line 2-2 in Figure 1.

The pneumatic tire 10 shown in Figure 1 may be mounted on a rim (not shown) for rotation about an axis A which substantially coincides with the axis of the toroid shape of the tire.

Referring to Figure 2, tire 10 is shown in section specifically to show the molded shape. It should be understood that reinforcing members, such as the conventional belting found in pneumatic vehicle tires has been eliminated from this drawing to better understand the structural features of the present tire. Tire 10 is formed with means 13 for securing the tire 10 to a rim. The securing means may include roll-restraining hoops or beads. In a tire such as that described in our U.S. Patent Specification No.

3,606,921 the tire includes a cylindrical inner wall 12 which may be considered as a portion of the securing means 13. It can be seen from Figure 2 that inner wall 12 may be composed of two unitarily formed portions, each forming an acute angle with a plane P passing through the center line of the tire.

Radiating divergingly outwardly from the securing means 13 and generally from axis A, are first sidewall members 14 and 16. The first sidewall members may each diverge from the plane P at an angle of less than 30".

Affixed to and converging inwardly from the outer ends 18 and 20 of first sidewalls 14 and 16 toward the plane P at an angle of less than 20 are second sidewalls 22 and 24.

The angled intersection at outer end 18 and 20 between first sidewall 14 and second sidewall 22 may be an angle, for example, of greater than 140". A similar angle may be found between second sidewall 24 and first sidewall 16.

Interconnecting the second sidewalls 22 and 24 is an annular tread wall 26 upon which a plurality of tread bars 28 may be unitarily formed.

Each tread bar 28 extends, in the embodiment shown, in one direction generally axially inwardly from the second sidewall 22 or 24 to generally the center of tread wall 26 wherein the next adjacent tread bar extending inwardly from the opposite sidewall 24 is intersected. Although the embodiment herein shown and described illustrates the tread bars 28 in an axial orientation, the tread bars 28 may also be angularly disposed relative to axis A. At the point of intesection a continuous center ridge 30 is formed about the circumference of the tire 10. Interposed between adjacent tread bars 28 located on the same side of plane P is a groove 32.

The first and second sidewalls, as shown in Figure 2, together extend outwardly in a generally semi-circular manner from securing means 13, with first walls 14 and 16 generally of one ply to insure the main point of flexure is located in first walls near securing means. The internal surface thus defined by the securing means 13, the sidewalls, and the tread wall connecting the second sidewalls has a longer axial dimension than radial dimension. With the cylindrical inner wall 12 interconnecting first sidewalls 14 and 16, the surface is generally oval in cross-section.

Each tread bar 28 extends radially inwardly from the tread wall 26 toward the respective first sidewall terminating at point 18 or 20, as the case may be. The extension of the tread bar in the vicinity of points 18 and 20 forms buttress 33, the plurality of buttresses forming interrupted deflector ring 34 about the sidewalls of the tire. In addition to forming the interrupted deflector ring 34, each buttress 33 of tread bar 28 serves to reinforce the second sidewall 22 or 24 which is purposely made relatively thicker than the first sidewall 14 or 16, respectively. This reinforcing of the second sidewall and the structure of the second sidewall being thicker than the first sidewall causes the main point of flexure of the tire under load conditions to be generally at the mid-point 36 of the first sidewalls 14 and 16. The nature of the structure of the first sidewall is such that the thinnest point of the sidewall and thus the most vulnerable point occurs generally at mid-point 36. The angle of second sidewalls 22 and 24, and hence the angle of buttress 33, which conforms to the angular structure of the second sidewalls, is chosen to form interrupted deflector ring 34 so that foreign objects in the path of the tire rotating about axis A, while mounted on an earthmoving vehicle, are deflected outwardly away from first sidewalls 14 and 16 and thus the midpoint 36 by the plurality of buttresses 33.

Previous deflector rings which have generally been continuous, have suffered from relatively gradual stripping from the tire carcass following a cut of the deflector ring by a rock or the like during the deflection process. Such stripping of the carcass results in premature failure of the tire. Accordingly, the use of an interrupted structure formed by extending the tread bar downwardly to a point adjacent the main point of flexure provides a unique interrupted deflector ring which will not strip as a rock cut is isolated to one or two tread bars. Thus, in the event buttress 33 of tread bar 28 is cut, the individual tread bar 28 is, in fact, damaged; however, there is little likehood of the damage stripping or progressing to the adjacent tread bar which has been the case in the continuous deflector rings described in earlier patents.

In operating, it is found that the tire 10 flexes at the point 36 with foreign objects deflected away from the flexure point 36 by the interrupted deflector ring 34. In the event a buttress 33 is damaged during operation, the next adjacent buttress 33 will not suffer due to the groove 32 interrupting the continuum of tire material.

WHAT WE CLAIM IS 1. A pneumatic tube tire comprising means for mounting the tire on a wheel; a pair of first sidewalls radially outwardly extending axially divergingly form the mounting means; a pair of second sidewalls each integral with and radially outwardly extending axially convergingly from a respective one of the first sidewalls; and an

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. understand the structural features of the present tire. Tire 10 is formed with means 13 for securing the tire 10 to a rim. The securing means may include roll-restraining hoops or beads. In a tire such as that described in our U.S. Patent Specification No. 3,606,921 the tire includes a cylindrical inner wall 12 which may be considered as a portion of the securing means 13. It can be seen from Figure 2 that inner wall 12 may be composed of two unitarily formed portions, each forming an acute angle with a plane P passing through the center line of the tire. Radiating divergingly outwardly from the securing means 13 and generally from axis A, are first sidewall members 14 and 16. The first sidewall members may each diverge from the plane P at an angle of less than 30". Affixed to and converging inwardly from the outer ends 18 and 20 of first sidewalls 14 and 16 toward the plane P at an angle of less than 20 are second sidewalls 22 and 24. The angled intersection at outer end 18 and 20 between first sidewall 14 and second sidewall 22 may be an angle, for example, of greater than 140". A similar angle may be found between second sidewall 24 and first sidewall 16. Interconnecting the second sidewalls 22 and 24 is an annular tread wall 26 upon which a plurality of tread bars 28 may be unitarily formed. Each tread bar 28 extends, in the embodiment shown, in one direction generally axially inwardly from the second sidewall 22 or 24 to generally the center of tread wall 26 wherein the next adjacent tread bar extending inwardly from the opposite sidewall 24 is intersected. Although the embodiment herein shown and described illustrates the tread bars 28 in an axial orientation, the tread bars 28 may also be angularly disposed relative to axis A. At the point of intesection a continuous center ridge 30 is formed about the circumference of the tire 10. Interposed between adjacent tread bars 28 located on the same side of plane P is a groove 32. The first and second sidewalls, as shown in Figure 2, together extend outwardly in a generally semi-circular manner from securing means 13, with first walls 14 and 16 generally of one ply to insure the main point of flexure is located in first walls near securing means. The internal surface thus defined by the securing means 13, the sidewalls, and the tread wall connecting the second sidewalls has a longer axial dimension than radial dimension. With the cylindrical inner wall 12 interconnecting first sidewalls 14 and 16, the surface is generally oval in cross-section. Each tread bar 28 extends radially inwardly from the tread wall 26 toward the respective first sidewall terminating at point 18 or 20, as the case may be. The extension of the tread bar in the vicinity of points 18 and 20 forms buttress 33, the plurality of buttresses forming interrupted deflector ring 34 about the sidewalls of the tire. In addition to forming the interrupted deflector ring 34, each buttress 33 of tread bar 28 serves to reinforce the second sidewall 22 or 24 which is purposely made relatively thicker than the first sidewall 14 or 16, respectively. This reinforcing of the second sidewall and the structure of the second sidewall being thicker than the first sidewall causes the main point of flexure of the tire under load conditions to be generally at the mid-point 36 of the first sidewalls 14 and 16. The nature of the structure of the first sidewall is such that the thinnest point of the sidewall and thus the most vulnerable point occurs generally at mid-point 36. The angle of second sidewalls 22 and 24, and hence the angle of buttress 33, which conforms to the angular structure of the second sidewalls, is chosen to form interrupted deflector ring 34 so that foreign objects in the path of the tire rotating about axis A, while mounted on an earthmoving vehicle, are deflected outwardly away from first sidewalls 14 and 16 and thus the midpoint 36 by the plurality of buttresses 33. Previous deflector rings which have generally been continuous, have suffered from relatively gradual stripping from the tire carcass following a cut of the deflector ring by a rock or the like during the deflection process. Such stripping of the carcass results in premature failure of the tire. Accordingly, the use of an interrupted structure formed by extending the tread bar downwardly to a point adjacent the main point of flexure provides a unique interrupted deflector ring which will not strip as a rock cut is isolated to one or two tread bars. Thus, in the event buttress 33 of tread bar 28 is cut, the individual tread bar 28 is, in fact, damaged; however, there is little likehood of the damage stripping or progressing to the adjacent tread bar which has been the case in the continuous deflector rings described in earlier patents. In operating, it is found that the tire 10 flexes at the point 36 with foreign objects deflected away from the flexure point 36 by the interrupted deflector ring 34. In the event a buttress 33 is damaged during operation, the next adjacent buttress 33 will not suffer due to the groove 32 interrupting the continuum of tire material. WHAT WE CLAIM IS

1. A pneumatic tube tire comprising means for mounting the tire on a wheel; a pair of first sidewalls radially outwardly extending axially divergingly form the mounting means; a pair of second sidewalls each integral with and radially outwardly extending axially convergingly from a respective one of the first sidewalls; and an

annular tread wall integral with and connecting the pair of second sidewalls, the tire thereby having a generally semi-circular sidewall portion between the tread wall and the mounting means, the annular tread wall including a plurality of tread bars, each tread bar extending radially inwardly along one of the second sidewalls towards the first sidewall to form a buttress along the second sidewall to form thereby an interrupted deflector ring.

2. A tire according to claim 1, wherein the first sidewalls are thinner than the second sidewalls.

3. A tire according to claim 1 or claim 2, wherein the second sidewalls each converge with the central radial plane of the tire at an angle of less than 20 .

4. A tire according to any of claims 1 to 3, wherein the first sidewalls each diverge from the central radial plane of the tire at an angle of less than 30".

5. A tire according to any of claims 1 to 4, wherein the first and second sidewalls meet at an internal angle greater than 140".

6. A tire according to any of claims 1 to 5, wherein each alternate tread bar extends inwardly from one of the second sidewalls with the adjacent tread bars extending inwardly from the other second sidewall.

7. A tire according to claim 6, wherein the tread bars each extend to a position on the far side of the central radial plane of the tire from the respective side wall from which they extend, whereby the tread bars for a continuous center ridge about the annular tread wall.

8. A tire according to any of claims 1 to 7, wherein the internal surface defined by the mounting means, sidewalls and tread wall is longer in an axial dimension that in a radial dimension.

9. A tire according to any of claims 1 to 8, wherein the tread bars are axially oriented.

10. A tire according to any of claims 1 to 9, wherein the means for mounting the tire on a wheel further comprises a cylindrical inner wall including roll-restraining means, the cylindrical inner wall interconnecting the pair of first sidewalls.

11. A tire according to claim 1, substantially as described with reference to the accompanying drawings.