GB2330810A

GB2330810A - Reinforced endless track

Info

Publication number: GB2330810A
Application number: GB9819582A
Authority: GB
Inventors: Matthew J Beatty; Dennis J Olson; Hitoshi Akiyama
Original assignee: Bridgestone Firestone Inc
Current assignee: Bridgestone Firestone Inc
Priority date: 1997-09-30
Filing date: 1998-09-08
Publication date: 1999-05-05
Also published as: DE19844309A1; KR19990030174A; ITTO980815A1; FR2768986B1; IT1312365B1; CA2248783A1; FR2768986A1; TW414769B; GB9819582D0; JPH11157471A

Abstract

An endless elastomeric track (10) for a tractor or crawler includes an elastomeric body having an outer surface (22) and an inner surface (16). A series of lugs project from the inner surface (16) and engage a series of wheels that drive the track (10). A second series of lugs (20) extends from the outer surface (22) to provide traction between the track (10) and the ground. A ply of main cords (28) is carried in the elastomeric body (26) in a longitudinal arrangement. Two reinforcing pies (32 and 34) are carried between the ply of main cords (28) and the outer surface (22) of the track (10). A lateral ply (36) is carried in the elastomeric body between the main cord (28) and the inner surface (16) of the track (10). The lateral ply (36) wraps around the lateral edges (38) in a pair of wrapped portions (42 and 44). The lateral ply (36) then extends inwardly as a pair of extensions (46 and 48) that do not extend completely across the span of the main cords (28). The extensions (46 and 48) are disposed between the ply of main cords (28) and the first reinforcing ply (32).

Description

2330810 inner Transverse Ply for an Endless Elastomeric Track The present

invention relates generally to the basic structure of the flexible, endless elastomeric track which is used on tractors and crawlers. More particularly, the present invention relates to the arrangement of the inner transverse ply in an elastomeric track having multiple piles of wire reinforcements. Specifically, the invention relates to an elastomeric track having at least a longitudinal ply of main cord wires with an inner transverse ply of laterally disposed wires extending entirely across the main cord wires and being wrapped around the lateral edges of the main cord ply.

Numerous agricultural and construction vehicles move about on endless tracks that are stretched over a plurality of wheels such that relatively long, substantially flat areas of the tracks engage the ground over which the vehicle is traveling. The tracks are typically used on vehicles that must move about over rough or broken ground. As suc-,,, the tracks are subject to a significant amount of abuse from debris commonly found in these environments. In addition, the tracks experience substantial forces due to the sizes of the tracks and vehicles.

Endless tracks may be fabricated from an elastomedc material. The elastomeric material provides numerous advantages over the metal-linked tracks of the past. It is, however, often necessary to reinforce elastomeric tracks with reinforcing cables to provide strength and durability to the track. One problem with manufacturing reinforced tracks is that the manufacturer must maintain the alignment of the cables while the track is being formed.

Providing plies of reinforcing cables in an endless elastomeric track is known in the art to provide stability to the track. US-A-4 721 498 discloses such a reinforced track having a plurality of wire cable plies disposed to stabilize the track during use. The disclosed track includes a first ply having longitudinally disposed wires adjacent to a second ply of wires disposed at a positive angle with respect to the longitudinal direction of the track. A third ply is adjacent the second ply and includes wires disposed at a negative angle that is larger than the angle of the second ply. The track further includes a fourth ply of wires that are laterally disposed. In another embodiment of the invention, the patent teaches that it is advantageous to form the second and third plies at equal but opposed angle while forming the third ply differently than the second ply. Specifically, the patent discloses that it is advantageous to form the third ply with fewer ends or from a smaller diameter cable. The patent teaches that the combination of the plies substantially neutralizes the shear stresses generated from tensile loading of the belt.

2 3C US-A-5 211 609 discloses another reinforced elastomeric drive belt having a plurality of wire plies disposed at opposing angles. The belt has a first longitudinal ply adjacent a second ply that is disposed at a positive angle with respect to the longitudinal direction. A third ply is disposed adjacent the second ply but is disposed at a negative angle with respect to the longitudinal direction. The patent teaches that it is advantageous that both of these angles are substantially equal. A fourth ply is laterally disposed over the third ply. As taught in US-A-4 721 498, US-A-5 211 609 teaches that the arrangement of these plies substantially neutralizes lateral forces to provide balance to the drive belt. US-A-5 575 729 is another patent that discloses a reinforced elastomeric drive belt having wire plies disposed in different orientations. This patent teaches that two laterally disposed plies may be separated by a third ply that includes two cables spirally wound on each side of the layer. One of the cables is wound in the S direction (right hand spiraling) while the other wire is wound in the Z direction (left hand spiraling). The patent teaches that this arrangement affords a balance of all lateral forces that would negatively effect the tracking of the belt.

It has been desired to provide an endless elastomeric track having an improved ply arrangement that improves the stability of the track.

It has also been desired to provide an endless elastomer track that has increased protection of its longitudinal main cords.

It has also been desired to provide an endless elastomeric track that has a ply of transverse wires disposed inside the longitudinal cords that protect 1 3 5:

the main cords while providing increased strength and stability to the track.

It has also been desired to provide an endless elastomeric track having an inner transverse ply that wraps around the lateral edges of the longitudinal main cords.

It has also been desired to provide an endless elastomeric track having an inner transverse ply that wraps around ail of the other reinforcing plies of the track so that the hazardous edges of the plies are covered.

The invention provides an improved endless track, the general nature of which may be stated as including an endless body having an inner surface and an outer surface, the endless body having a longitudinal axis; a ply of main cords carried by the endless body substantially parallel to the longitudinal axis; the ply of main cords having a pair of lateral edges, a bottom surface facing the inner surface of the track, and a top surface facing the outer surface of the track; a lateral ply of reinforcing cords disposed between the ply of main cords and the inner surface of the track; and the lateral ply extending entirely across the bottom surface of the ply of main cords and including a pair of wrapping portions that wrap around the lateral edges of the ply of main cords.

Although the prior art patents referred to above disclose the desirability of creating an elastomeric drive belt or track with pluralities of wire plies disposed to neutralize lateral forces, none of the patents teaches, discloses or suggests the desirability of wrapping one of the plies over another of the plies to increase the stability of the track. Further, none of the prior-art has recognized that it is desirable to provide an inner protective ply that wraps around the lateral edges of the main cord ply to provide additional protection to the main cord ply. It is thus desired in the art to provide an endless elastomeric track having a plurality of reinforcing plies with at least one of the plies wrapped around at least another of the plies to improve the stability of the track.

Preferred embodiments of the invention, illustrative of the best mode in which applicants have contemplated applying the principles, are set forth in the following description and are shown in the drawings, in which:

Fig. 1 is a diagrammatic side view of an endless elastomeric track according to the present invention disposed about a plurality of wheels; Fig. 2 is a fragmented, sectional perspective view of the endless elastomeric track of Fig. 1 depicting the arrangement of the wire plies; Fig. 3 is an enlarged sectional view taken along line 3-3 of Fig. 2 depicting the end arrangement of the wire plies; Fig. 4 is a fragmented, sectional perspective view of another embodiment of the endless elastomeric track of the present invention depicting the arrangement of the wire plies; and Fig. 5 is an enlarged sectional view taken along line 5-5 of Fig. 4 depicting the end arrangement of the wire plies.

An endless elastomeric track according to the present invention is indicated generally by the numeral 10 in the accompanying drawings. When in use, track 10 is mounted on at least two wheels 12 that maintain the position of track 10. At least one of wheels 12 is typically a drive wheel 14 that engages the inner surface 16 of track 10 and causes track 10 to rotate about wheels 12 and 14 in an endless fashion. A series of lugs 18 preferably are formed along inner surface 16 of track 10 to enable wheels 12 and 14 to engage and drive track 10. Most tracks 10 further include a plurality of lugs 20 formed on the outer surface 22 of track 10 so that the vehicle using track 10 has the traction desired by users of heavy equipment.

Track 10 includes an elastomeric body 26 wherein a calendered ply of main reinforcing cords 28 and the plies of wire reinforcements are carried. Ply of main reinforcing cords 28 runs continuously about the track 10 in the endless direction which is parallel to a longitudinal axis 30 of the track 10. In the embodiment of track 10 depicted in FIGS. 1-3, ply 28 is disposed inwardly of two calendered reinforcing plies 32 and 34 such that main cord ply 28 is disposed between plies 32 and 34 and inner surface 16 of track 10. Reinforcing plies 32 and 34 are formed from a plurality of individual wires having a diameter that is typically somewhat smaller than the diameter of the cords in main cord ply 28. The wires of reinforcement plies 32 and 34 are disposed at equal but opposite angles with respect to longitudinal axis 30 of main cord ply 28. Preferably, this angle is 35 degrees for each ply 32 and 34. The disposition of plies 32 and 34 equalizes the lateral forces in track 10 and allows track 10 to rotate about wheels 12 and 14 without excessive frictional forces. 6 Track 10 also has a calendered inner lateral ply 36. Inner lateral ply 36 is disposed between main cord ply 28 and inner surface 16 of track 10. Ply 36 serves to protect the main cord ply 28 from damage resulting from penetration from inner surface 16 of track 10. Such penetration can occur because track 10 is typically exposed when mounted on wheels 12 and 14.

Inner lateral ply 36 is formed from a plurality of cords disposed at substantially right angles to longitudinal axis 30 of track 10. In accordance with one of the main features of the invention, inner ply 36 extends laterally across the entire bottom surface 37 of main cord ply 28 and wraps around each of the lateral edges 38 and 40 of main cord ply 28 to form a pair of wrapped portions 42 and 44. Inner ply 36 then extends partially back across the top surface 45 of main cord ply 28 with partial extensions 46 and 48. Extensions 46 and 48 are disposed between top surface 45 of main cord ply 28 and reinforcement plies 32 and 34.

Lateral ply 36 and wrapped portions 42 and 44 are spaced from main cord ply 28 by the material of elastomeric body 26. Extensions 46 and 48 extend only partially across the top width of main cord ply 28 leaving a middle portion 50 of top surface 45 of main cord ply 28 uncovered by lateral ply 36. In a preferred embodiment of the invention, extensions 46 and 48 each extend approximately 100 to 150mm (four to six inches) inwardly from lateral edges 38 and 40. If desirable, extensions 38 and 40 may extend entirely across ply 28. Wrapped portions 42 and 44 and extensions 46 and 48 protect lateral edges 38 and 40 from damage. Wrapped portions 42 and 44 and extensions 46 and 48 also provide strength and stiffness to track 10. By providing the wrapped portions 42 and 44, the main cord ply 28 is prevented from wandering during the manufacturing 7 processes.

Another embodiment of the endless track is depicted in FIGS. 4 and 5 and is indicated generally by the numeral 100. When in use, track 10 is mounted on a plurality of wheels (not shown) that engage the inner surface 116 of track 100 and cause track 100 to rotate about the wheels in an endless fashion. A plurality of lugs 120 are formed on the outer surface 122 of track 100 so that the vehicle using track 100 has the traction desired by users of heavy equipment.

Track 100 includes an elastomeric body 126 wherein a calendered ply of main reinforcing cords 128 and the plies of wire reinforcements are carried. Ply of main reinforcing cords 128 runs continuously about the track 100 in the endless direction which is parallel to a longitudinal axis 130 of the track 100. In the embodiment of track 100 depicted in the drawings, ply 128 is disposed inwardly of two calendered reinforcing plies 132 and 134 such that main card ply 128 is disposed between plies 132 and 134 and inner surface 116 of track 100. Reinforcing plies 132 and 134 are formed from a plurality of individual wires having a diameter that is typically somewhat smaller than the diameter of the cords in main cord ply 128. The wires of reinforcement plies 132 and 134 are disposed at equal but opposite angles with respect to longitudinal axis 130 of main cord ply 128. The disposition of plies 132 and 134 equalizes the lateral forces in track 100 and allows track 100. The lateral edges 152 of the plies 132 and 134 are somewhat hazardous during the manufacturing process b ecause the small, individual wires of the plies 132 and 134 protrude from their elastomeric coating and create sharp edges.

8 Track 100 also has a calendered inner lateral ply 136. Inner lateral ply 136 is disposed between main cord ply 128 and inner surface 116 of track 100. Ply 136 serves to protect the main cord ply 128 from damage resulting from penetration from inner surface 116 of track 100. Such penetration can occur because track 100 is typically exposed when mounted on a vehicle.

Inner lateral ply 136 is formed from a plurality of cords disposed at substantially right angles to longitudinal axis 130 of track 100. In accordance with one of the main features of the invention, inner ply 136 extends laterally across the entire bottom surface 137 of main cord ply 128 and wraps around each of the lateral edges 138 and 140 of main cord ply 128 and the lateral edges 152 of the reinforcing plies 132 and 134 to form a pair of wrapped portions 142 and 144. Inner ply 136 then extends partially back across the top surface 154 of top reinforcing ply 134 with partial extensions 146 and 148. Extensions 146 and 148 are disposed between top surface 154 of and outer surface 122 of track 100. In a preferred embodiment, extensions 146 and 148 each extend inwardly approximately loo to 150mm (four to six inches) from lateral edges 152.

Lateral ply 136 and wrapped portions 142 and 144 are spaced from main cord ply 128 and reinforcing plies 132 and 134 by the material of elastomeric body 126. Extensions 146 and 148 extend only partially across the top width of main cord ply 128 leaving a middle portion 150 of top surface 145 of main cord ply 128 uncovered by lateral ply 136. Wrapped portions 142 and 144 and extensions 146 and 148 protect lateral edges 138, 140, and 152 from damage. Wrapped portions 142 and 144 and extensions 146 and 148 also provide strength and stiffness to track 100. Wrapped portions 142 and 144 also protect handlers of track 100 from exposed edges 152 during 9 the manufacturing process.

in the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirement of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described.

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Claims

Claims i 5 An endless elastomeric track comprising: an endless body having

an inner surface and an outer surface and a longitudinal axis; a ply of main cords carried by said endless body substantially parallel to said longitudinal axis, the ply of main cords having a pair of lateral edges, a bottom surface facing the inner surface of the track, and a top surface facing the outer surface of the track; a lateral ply of reinforcing cords disposed between the ply of main cords and the inner surface of the track, and the lateral ply extending entirely across the bottom surface of the ply of main cords and including a pair of wrapping portions that wrap around the lateral edges of the ply of main cords.
2. An endless elastomeric track according to claim 1 wherein the lateral ply is spaced from the ply of main cords by the body.
3. An endless elastomeric track according to claim 1 or 2 wherein the wrapping portions are spaced from the ply of main cords by the body.
4. An endless elastomeric track according to claim 1 or 2 further comprising a pair of reinforcing plies carried by the body between the outer surface of the body and the ply of main cords.
5. An endless elastomeric track according to claim 4 wherein one of the pair of reinforcing plies includes a plurality of reinforcing wires disposed at a first angle with respect to the longitudinal axis 12 - of the body and the other of the pair of reinforcing plies includes a plurality of reinforcing wires disposed at a second angle with respect to the said longitudinal axis, the first angle being equal and opposite to the second angle.
6. An endless elastomeric track according to any preceding claim wherein the lateral ply includes a pair of extensions that extends back across the top surface of the ply of main cords.
7. An endless elastomeric track according to claim 6 wherein the extensions are disposed between the top surface of the ply of main cords and the outer surface of the body.
8. An endless elastomeric track according to claim 6 or 7 wherein the extensions only partially extend across the top surface of the ply of main cords.
9. An endless elastomeric track according to claim 6, 7 or 8 wherein the extensions are spaced from the ply of main cords by the endless body.
10. An endless elastomeric track comprising:

a body having an inner surface and an outer surface, the said body having a longitudinal axis; a plurality of plies of reinforcing members carried by the body and extending continuously substantially parallel to the said longitudinal axis, each of the plurality of plies of reinforcing members having lateral edges; at least one of the plurality of plies of reinforcing members wrapping around another of the plurality of plies of reinforcing members.

13 -
11. An endless elastomeric track comprising: a main reinforcing ply of reinforcing members embedded in the track, the members extending substantially parallel to the longitudinal axis of the track; and a lateral reinforcing ply disposed between the main reinforcing ply and the inner surface of the track, the edge portions of the lateral reinforcing ply being wrapped around the edges of the main reinforcing ply.
12. An endless elastomeric track substantially as described with reference to the drawings.