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Title:
SPROCKET WITH DEBRIS REMOVING CHANNEL
Document Type and Number:
WIPO Patent Application WO/2008/037008
Kind Code:
A1
Abstract:
A sprocket (10) of a tracked vehicle, said vehicle having at least one endless track adapted to support the vehicle from the ground and to cause movement of the vehicle over the ground, said sprocket engaging the chain to support the vehicle relative to the chain, said sprocket being formed around its periphery with a plurality of teeth (14) with tooth spaces (16) being defined between the teeth, said tooth spaces being intended in use to engage substantially cylindrical surfaces provided by pin assemblies of the chain and which are located at spaced intervals along the chain, each tooth space defining an accurate engagement face (18) which is intended to engage the cylindrical surfaces, the engagement faces extending between the opposed side faces of the sprocket and each having a configuration which is complementary to the portion of the cylindrical surfaces to be engaged thereby, each engagement faces having at least one transverse channel (20) extending across the engagement face from an inner end (23) located at an intermediate position across the engagement face and opening at its outer end (24) to at least one side of the sprocket.

Inventors:
PIACENTINI COLIN MICHAEL (AU)
HYDER CLAYTON (AU)
Application Number:
PCT/AU2007/001426
Publication Date:
April 03, 2008
Filing Date:
September 26, 2007
Export Citation:
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Assignee:
SUPER TRACK ENTPR PTY LTD (AU)
PIACENTINI COLIN MICHAEL (AU)
HYDER CLAYTON (AU)
International Classes:
B62D55/088; B62D55/20; F16H7/06; F16H55/30
Domestic Patent References:
WO2003067124A12003-08-14
Foreign References:
BE904056A1986-05-15
Other References:
DATABASE WPI Week 200381, Derwent World Patents Index; Class Q22, AN 2003-872546
DATABASE WPI Week 199841, Derwent World Patents Index; Class Q22, AN 1998-476222
DATABASE WPI Week 200004, Derwent World Patents Index; Class Q64, AN 2000-051384
DATABASE WPI Week 198050, Derwent World Patents Index; Class Q64, AN 1980-L9422C
Attorney, Agent or Firm:
WRAY & ASSOCIATES (1 William StreetPerth, Western Australia 6000, AU)
Download PDF:
Claims:

Claims

The Claims Defining the Invention is as Follows:

1 . A sprocket of a tracked vehicle, said vehicle having at least one endless track adapted to support the vehicle from the ground and to cause movement of the vehicle over the ground, said sprocket engaging the chain to support the vehicle relative to the chain, said sprocket being formed around its periphery with a plurality of teeth with tooth spaces being defined between the teeth, said tooth spaces being intended in use to engage substantially cylindrical surfaces provided by pin assemblies of the chain and which are located at spaced intervals along the chain, each tooth space defining an engagement face which is intended to engage the cylindrical surfaces, the engagement faces extending between the opposed side faces of the sprocket and each having a configuration which is complementary to the portion of the cylindrical surfaces to be engaged thereby, each engagement faces having at least one transverse channel extending across the engagement face from an inner end located at an intermediate position across the engagement face and opening at its outer end to at least one side of the sprocket.

2. A sprocket as claimed at claim 1 wherein the cross-sectional area of the channel increases in the direction towards said outer end.

3. A sprocket as claimed at claim 2 wherein the increase in cross-sectional area is provided by an increase in the depth of the channel.

4. A sprocket as claimed at claim 2 or 3 wherein the increase in cross- sectional area is provided by an increase in the width of the channel.

5. A sprocket as claimed at any one of the preceding claims wherein the channel extends the full width of the socket so as to open onto both sides of the sprocket.

6. A sprocket as claimed at claim 5 the channel has its minimum cross- sectional area at a position located substantially centrally across the width of the sprocket.

7. A sprocket as claimed at any one of the preceding claims wherein each tooth space is provided with only one channel

8. A sprocket as claimed at any one of the preceding claims wherein the channel is located at the base of the tooth space.

9. A sprocket of a tracked vehicle substantially as herein described with reference to the accompanying drawings.

10. A chain and sprocket assembly of a tracked vehicle, said vehicle having at least one endless track adapted to support the vehicle from the ground and to cause movement of the vehicle over the ground, said sprocket engaging the chain to support the vehicle relative to the chain, wherein the sprocket comprises a toothed sprocket as claimed at any one of claims 1 to 9.

An endless track for a tracked vehicle, the endless track comprising a track chain in engagement with a toothed sprocket, the toothed sprocket being of the form as claimed at any one of claims 1 to 9.

Description:

"Sprocket with Debris Removing Channel"

Field of the Invention

This invention relates to a sprocket for a chain and sprocket assembly.

The invention has been devised particularly, although not necessarily solely, for use in relation to a chain and sprocket assembly in an endless track for a tracked vehicle, such as for example a bulldozer, grader or shovel.

Background Art

Tracked vehicles such as bulldozers, graders and shovels are often required to operate in environments containing abrasive materials such as sand, dust, dirt and mud. In such environments, abrasive material can accumulate in the chain sprocket at the interface between the sprocket and the portion of the chain engaging the sprocket. This can lead to premature wear of that part of the chain which engages the sprocket, as well as the part of the sprocket which is engaged by the chain. Further, the accumulated material can cause the chain to dislodge from the sprocket.

It is against this background, and the problems and difficulties associated therewith that the present invention has been developed.

Disclosure of the Invention

Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

According to a first aspect of the invention there is provided a sprocket of a tracked vehicle, said vehicle having at least one endless track adapted to support the vehicle from the ground and to cause movement of the vehicle over the ground, said sprocket engaging the chain to support the vehicle relative to the chain, said sprocket being formed around its periphery with a plurality of teeth with

tooth spaces being defined between the teeth, said tooth spaces being intended in use to engage substantially cylindrical surfaces provided by pin assemblies of the chain and which are located at spaced intervals along the chain, each tooth space defining an engagement face which is intended to engage the cylindrical surfaces, the engagement faces extending between the opposed side faces of the sprocket and each having a configuration which is complementary to the portion of the cylindrical surfaces to be engaged thereby, each engagement faces having at least one transverse channel extending across the engagement face from an inner end located at an intermediate position across the engagement face and opening at its outer end to at least one side of the sprocket.

According to a preferred feature of the invention the cross-sectional area of the channel increases in the direction towards said outer end. According to a preferred feature of the invention the increase in cross-sectional area is provided by an increase in the depth and/or width of the channel.

According to a preferred feature of the invention the channel extends the full width of the socket so as to open onto both sides of the sprocket.

According to a preferred feature of the invention the channel has its minimum cross-sectional area at a position located substantially centrally across the width of the sprocket.

According to a preferred feature of the invention each tooth space is provided with only one channel

According to a preferred feature of the invention the channel is located at the base of the tooth space.

According to another aspect of the invention resides in a chain and sprocket assembly of a tracked vehicle, said vehicle having at least one endless track adapted to support the vehicle from the ground and to cause movement of the vehicle over the ground, said sprocket engaging the chain to support the vehicle relative to the chain, wherein the sprocket comprises a toothed sprocket as described above.

According to another aspect of the invention resides in an endless track for a tracked vehicle, the endless track comprising a track chain in engagement with a toothed sprocket, the toothed sprocket being of the form as described above.

The invention will be better understood by reference to the following description of one specific embodiment thereof.

Brief Description of the Drawings

The invention will be made with reference to the accompanying drawing which is a fragmentary perspective view of a sprocket according to the embodiment.

Detailed description of Specific Embodiment

The first embodiment of the invention as shown in the drawings is directed to a toothed sprocket 10 adapted for engagement with an endless track chain (not shown) of a tracked vehicle such as a bulldozer, grader or shovel.

The toothed sprocket 10 comprises a rim 12 having two opposed sides 13 and a plurality of teeth 14. A tooth space 16 exists between each two adjacent teeth 14. Each tooth space 16 is defined by an arcuate face 18 provided on the rim 12, the arcuate face defining not only the tooth space 16 but also portions of the two adjacent teeth 16. The arcuate face 18 is intended to engage the pin assembly of the track chain. Such pin assemblies have an outer cylindrical surface. Accordingly the arcuate face has a complementary profile to the cylindrical surface such that it will closely engage the cylindrical surface for its full width.

A channel 20 is provided at the base of each arcuate face 18. The channel 20 comprises two channel sections 21, 22 each extending to an opening onto a respective one of the sides 13 of the sprocket 10. As a result each channel section 21 and 22 has an inner end 23, and an outer end 24 which opens to the respective side 13. In the arrangement shown, the inner ends 23 of the two channel sections 21 , 22 merge at crest 25 which is located centrally along the channel.

The cross-sectional area of each channel section 21 , 22 increases in the direction from the inner end 23 to the outer end 24. In the case of the first embodiment shown, the increase in cross-sectional area is achieved by an increasing width and an increasing depth in the direction from the inner end 23 to the outer end 24.

The presence of the channel 20 provides a flow path to each side of the sprocket along which abrasive matter (such as sand, dirt and mud) can be discharged as the chain moves into engagement with the tooth space. Typically, the chain comprises a roller chain having roller elements adapted to locate in the tooth spaces 16, in which case the abrasive matter is discharged as the roller elements engage in the tooth spaces.

The presence of the channel in the base of the arcuate face does not interfere with the loading which will be exerted between the arcuate face and the pin assembly and serves to enable material which becomes entrapped between the arcuate face and the cylindrical surface to be extruded to the outer side of the sprocket. Because of the configuration of each channel section, there is a higher pressure zone created within the accumulated material at the inner end of each channel section and a lower pressure zone created at the outer end, the pressure difference inducing flow of the accumulated material outwardly. In this way, accumulating abrasive material is expelled from the sprocket.

According to a second embodiment the transition between the inner ends 23 of the channel section may be smooth rather than being defined by the crest 25 of the first embodiment.

According to a third embodiment the inner ends of the two channel sections 21, 22 are separated from each other by a portion of the arcuate face to provide a landing therebetween.

According to a fourth embodiment of the invention the increase in cross-sectional area is achieved principally by an increasing width in the direction from the inner end 23 to the outer end 24.

According to a fifth embodiment of the invention the increase in cross-sectional area is achieved principally by an increasing depth in the direction from the inner end 23 to the outer end 24

From the forgoing, it is evident that the present invention provides a simple yet highly effective arrangement for displacing abrasive material which might otherwise accumulate in a sprocket wheel to cause premature wear and possibly also dislodgement of the chain in driving engagement with the sprocket.

The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, elements and methods are clearly within the scope of the invention as described herein.