Title of Invention

A TRACK APPARATUS

Abstract

A track apparatus (10) mountable on a rotatable axle of a vehicle, the track apparatus comprising a continuous flexible track (15) having a main inner surface (28) and spaced track lugs (32) projecting therefrom, each track lug (32) terminating in a distal surface (32a) spaced inwardly from the main inner surface and a drive wheel (12) mountable on the axle for driving the flexible track about the axle, the drive wheel including a central hub (52), a radially-extending portion extending radially from the central hub and terminating at a radially outer edge, and an outer rim (24) connected with the outer edge, the outer rim (24) having lug-engagement surfaces (29), whereby the track lugs (32) are received in lug-receiving gaps which are formed between corresponding pairs of drive members (30) projecting from the lug-engagement surfaces (29) of the outer rim (24) of the drive wheel (12), such that the major extent of the axial widths of the distal surfaces (32a) of the track lugs (32) engage the lug-engagement surfaces (29) of the outer rim (24) of the drive wheel in order that the lugs (32) are supported when driven by the drive wheel, thereby to minimize damage to the lugs (32) during operation of the track system.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See Section 10; rule 13] "A TRACK APPARATUS" AGTRACKS, INC., a US company of 204A Main Street, Mt. Vernon, IN 47620, USA, The following specification particularly describes the invention and the manner in which it is to be performed: GRANTED 11-7-2008 ORIGINAL IN/PCT/2002/443/MUM 11 JUL 2008 The present invention relates to a track apparatus. FIELD OF THE INVENTION This invention relates generally to track apparatus for vehicles. In particular, this invention relates to track apparatus of the type for use in place of a vehicle wheel and, more particularly, to apparatus for driving the flexible tracks of such apparatus during vehicle operation. BACKGROUND OF THE INVENTION Agricultural vehicles such as tractors, combines and the like are commonly used in agricultural fields for a variety of jobs, and construction vehicles and other large work vehicles are used for many different jobs on a variety of ground surfaces. Typically, these vehicles have tires on which the vehicles are supported on the ground. These kinds of large vehicles are quite heavy, and their weight is distributed to a relatively small area by the vehicle tires. As a result, the tires of such vehicles tend to compact the soil in the fields or other ground surfaces. Compacted soil discourages growth of crops planted in the fields which need loose soil to flourish, and ground surface compaction is often undesirable for other reasons as well. In addition, since fields and other work sites are often wet due to rain or watering, vehicles which enter the fields become bogged down in the mud due to the fact that there is such a small tire area in contact with the ground. Therefore, it is highly desirable to develop a track apparatus for vehicles which spreads vehicle weight over a larger area so as to reduce the degree of ground compaction. Providing a larger ground-surface engagement area also serves to prevent vehicles from becoming bogged down in mud or other soft ground surfaces. Prior track systems for vehicles are disclosed in United States Patent Nos. Re36,284 (Kelderman) and 5,829,848 (Kelderman), assigned to the assignee of the present invention and incorporated herein by reference. The Kelderman '284 reissue and '848 patents disclose track suspension systems for vehicles having a frame and a continuous rubber track. The drive wheel is attached to the frame for engaging and driving the continuous flexible track. Each drive wheel of such prior apparatus has a plurality of drive projections disposed thereon which are between and engage corresponding rubber lugs extending from the inner surface of the flexible track. As the drive wheel rotates, the wheel projections engage the track lugs and drive the continuous flexible track. In such prior 5 apparatus, the terminal surfaces of the track lugs do not engage the drive wheel; in other words, the track lugs are substantially unsupported. All of the driving force is imparted on the track lugs by the drive projections of the drive wheel, and this shear force, imparted as it is on substantially unsupported track lugs, tends to cause cracking and premature wear of the track lugs. 10 Certain prior art track apparatus, also of the type for use in place of a vehicle wheel, has a drive wheel which also includes side structure to retain "the track lugs in engagement with the drive wheel ~ in an attempt to keep the track in proper alignment. In such prior apparatus, as with that described above, the terminal surfaces of the wheel lugs do not engage the drive wheel; in other words, the track lugs are 15 substantially unsupported. Such drive wheels, as with those referenced above, impose shear forces on the track lugs, in the manner described above. However, when there is a tendency toward track misalignment, the side structure of the drive wheel engages the lateral surfaces of the track lugs, and imposes torsional and further shearing forces on such track lugs. These torsional and shearing forces exacerbate the resulting 20 cracking and premature wear of the track lugs. Consequently, it would be highly desirable to provide a drive wheel which does not damage the flexible track after extended use. Likewise, it would be highly desirable to provide a drive wheel which would minimize shearing forces on rubber track lugs and would minimize or eliminate the torsional forces described above. 25 OBJECTS OF THE INVENTION It is an object of this invention to provide an improved track apparatus, of the type for use in place of a vehicle wheel, which overcomes some of the problems and shortcomings of the prior art, including those referred to above. More particularly, it is an object of this invention to providing an improved drive wheel for engaging and driving the flexible track of track apparatus of the type for use in place of a vehicle wheel ~ namely, a drive wheel which overcomes the problems and shortcomings of the prior art referred to above. 5 Another object of this invention is to provide a track apparatus drive wheel which does not damage the flexible track during extended me. Another object of this invention is to provide a track apparatus drive wheel which minimizes shearing forces on the lugs of flexible tracks used on such track apparatus. 10 Still another object of this invention is to provide a track apparatus drive wheel which minimizes or eliminates the torsional forces referred to above. Yet another object of this invention is to provide a track apparatus drive wheel which effectively drives the flexible belt in difficult work conditions. Another object of this invention to provide a track apparatus drive wheel which 15 is simple and inexpensive to manufacture. BRIEF SUMMARY OF THE INVENTION In accordance with the present invention, an improved drive wheel for track apparatus of the type mountable on the rotatable axle of a vehicle for driving a flexible 20 track is provided. The flexible track of such apparatus, when mounted, has upper and lower lengths, and the drive wheel drives the track by engagement with the upper length thereof. The track has an main inner surface and a plurality of spaced lugs projecting therefrom. The lugs each have leading and trailing surfaces and a pair of lateral surfaces, and each lug terminates in a distal end (terminal surface) which is a 25 generally flat surface spaced inwardly from the main inner surface of the track. This invention deals with the configuration of the drive wheel and its driving engagement with the flexible track, and the configurations and features of the invention overcome the above-noted shortcomings and problems. The drive wheel includes a central hub (central mounting portion) mountable 30 on the axle of the vehicle for rotational movement therewith. First and second side- surfaces extend radially from the central hub. The side-surfaces terminate at radially outer edges. An outer rim interconnects the outer edges of the side-surfaces. A plurality of spaced drive members project radially from the outer rim and define lug- receiving gaps therebetween ~ for receiving the track lugs. The drive members are 5 circumferentially spaced about the central hub. The outer rim is engageable with the terminal surfaces of the lugs when the lugs are in the lug-receiving gaps. It is contemplated to provide the outer rim with a plurality of spaced openings therein. The plurality of openings in the outer rim are circumferentially spaced about the central hub. 10 The drive wheel is preferably substantially free of side structure in positions which are both laterally adjacent to the lug-engagement surfaces between adjacent pairs of the drive members and radially beyond the circumferential edge of the radially-extending portion of the drive wheel. This allows the track lugs to be free to adjust their precise positions of engagement with the lug-engagement surfaces during 15 operation. This serves to minimize or substantially eliminate the harmful torsional forces. In accordance with a still further aspect of the present invention, a track apparatus mountable on a rotatable axle of the vehicle is provided. Such track apparatus has a drive wheel as described above, wherein an outer rim engages the 20 distal (terminal) surfaces of the lugs. The engagement of the terminal (distal) surfaces of the track lugs with the drive wheel outer rim during operation (when the track lugs are in the lug-receiving gaps) serves to overcome the above-mentioned problems of unacceptable cracking and premature wear of track lugs. The aforementioned openings in the outer rim allows 25 debris which may accumulate to past through the outer rim during operation. BRIEF DESCRIPTION OF THE DRAWINGS The drawings furnished herewith illustrate a preferred construction of the present invention in which the above advantages and features are clearly disclosed as well as others which will be readily understood from the following description of the illustrated embodiment. FIGURE 1 is a rear isometric view of a track apparatus for a vehicle incorporating a drive wheel in accordance with the present invention. 5 FIGURE 2 is a front isometric view of the track apparatus. FIGURE 3 is a front isometric view of the track apparatus with the Bexibie track removed. FIGURE 4 is a front elevation of the track apparatus. FIGURE 5 is an enlarged, fragmentary front elevation, partially in section, of a 10 portion of the track apparatus of FIGURE 1 showing engagement of the flexible track with the drive wheel. FIGURE 6 is a cross-sectional view of a portion of the track apparatus of FIGURE 1 showing engagement of the flexible track with the drive wheel. 15 DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENTS Referring to FIGURES 1-2, a track apparatus is generally designated by the reference numeral 10. In a preferred embodiment, the track apparatus 10 is mounted on an axle (not shown) of an agricultural vehicle such as a tractor or combine. However, it is contemplated as being within the scope of the present invention for 20 track apparatus 10 to be mounted on other types of vehicles such as trucks, automobiles, and the like. Track apparatus 10 includes a drive wheel 12 which is mountable to the axle of a vehicle for rotational movement therewith in order to drive a flexible track 15. As best seen in FIGURE 1, in the preferred embodiment, it is intended to mount track 25 apparatus 10 to a vehicle having a planetary axle. However, it is contemplated to mount track apparatus 10 to a bar axle or other type of axle without deviating from the scope of the present invention. Referring to FIGURE 2, drive wheel 12 includes a first set of circumferentially spaced attachment openings 18 therein which are aligned with corresponding openings 30 formed in an attachment flange extending radially from the axle of the vehicle, as is conventional. Bolts extend through attachment openings 18 in drive wheel 12 and through corresponding openings in the attachment flange of the axle and are secured by corresponding nuts threaded on the ends thereof in order to interconnect the axle of the vehicle to drive wheel 12 so as to allow drive wheel 12 to rotate in unison with the 5 axle of the vehicle. As best seen in FIGURES 1-3, drive wheel 12 includes an inner wall or side-surface 20 and an outer wall or side-surface 22 interconnected by a radially outer rim 24. Outer rim 24 includes a plurality of circumferentially spaced openings 26 therein for allowing debris which may accumulate on the inner surface 28 of flexible track 15 10 to pass therethrough. As shown in FIGURE 5, outer rim 24 further includes an outer surface 29 having a plurality of circumferentially spaced drive members 30 projecting radially therefrom. As hereinafter described, drive members 30 are intended to engage corresponding track lugs 32 projecting inwardly from the inner surface 28 of flexible track 15 in order to drive flexible track 15. 15 Drive wheel 12 is free of side structure in positions which are both laterally adjacent to the lug-engagement surfaces that are between adjacent pairs of drive members 30 and radially beyond circumferential edge 21 of radially-extending portion 20 of drive wheel 12. As noted above, this tends to minimize or substantially eliminate the harmful torsional forces discussed above. 20 In operation, track apparatus 10 is mounted to an axle of a vehicle through drive wheel 12 as heretofore described. The axle of the vehicle is rotated in a conventional manner through the vehicle by its engine and through a transmission which can vary the speeds and allow for forward and reverse rotation. Flexible track 15 of track apparatus 10 is positioned over drive wheel 12 such that track lugs 32 25 projecting from the inner surface 28 of flexible track 15 are received between corresponding pairs of drive members 30 projecting from outer surface 29 of outer rim 24 of drive wheel 12. As drive wheel 12 rotates, drive members 30 engage corresponding track lugs 32 and drive flexible track 15 about drive wheel 12. Thereafter, successive drive members 30 engage subsequent track lugs 32 extending from main inner surface 28 of flexible track 15 so as to drive flexible track 15 about drive wheel 12. As indicated above, and as shown best in FIGURES 5 and 6, the distal end surface 32a of track lugs 32 engages outer surface 29 of outer rim 24 of drive wheel 5 12 in order that track lugs 32 are supported when driven by drive wheel 12. Such full engagement is seen in FIGURE 6 and in the rightmost position of FIGURE 5. Such full engagement, by which track 15 tends to minimize shearing forces on track lugs 32 and the possible twisting and turning of track lugs 32; hence, damage to track lugs 32 during operation of track apparatus 10 is significantly reduced, extending belt life. 10 Drive wheel 12 is free of side structure in positions which are both laterally adjacent to the lug-engagement surfaces that are between adjacent pairs of drive members 30 and radially beyond circumferential edge 21 of radially-extending portion 20 of drive wheel 12. As noted above, this tends to minimize or substantially eliminate the harmful torsional forces discussed above. 15 It is intended that terminal end surface 32a of such track lugs 32 engage outer surface 29 of outer rim 24 of drive wheel in order that lugs 32 are supported when driven by drive wheel 12, thereby minimizing the possible twisting and turning of track lugs 32, and hence, damage to lugs 32 during operation of track apparatus 10. As drive wheel 12 rotates, drive members 30 engage corresponding track lugs 32 and 20 drive flexible track 15 about drive wheel 12. Thereafter, successive drive members 30 engage subsequent lugs 32 extending from the inner surface 28 of flexible track 15 so as to drive flexible track 15 about drive wheel 12. The following is a brief description of the engagement of flexible track 15 with other components of track apparatus 10: As flexible track 15 approaches leading idler 25 wheels 137, track lugs 32 pass therebetween. In addition, the radially outer surfaces 137a of leading idler wheels 137 engage the inner surface 28 of flexible track 15 and direct the lower length of flexible track 15 into contact with a supporting surface such as a farmer's field. As flexible track 15 continues to be driven about drive wheel 12, track lugs 32 pass between the pairs of leading and trailing bogie wheels 101 and 107, 30 respectively. The radially outer surfaces 101a and 107a of bogie wheels 10land 107, respectively, engage the inner surface 28 of flexible track 15 along its lower length and insure contact of flexible track 15 with the supporting surface along the lower length of flexible track 15. Similarly, as flexible track 15 approaches trailing idler wheels 117, track lugs 32 on the inner surface 28 of flexible track 15 pass therebetween. The 5 radially outer surfaces 117a of idler wheels 117 engage the inner surface 28 of flexible track 15 and guide flexible track 15 onto drive wheel 12 to form a continuous loop. If drive wheel 12 is rotated in the opposite direction, trailing idler wheels 117 may function as leading idler wheels, and such that leading idler wheels 137 may function as trailing idler wheels, all as known in the art. 10 Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter as regarded as the invention. We claim: 1. A track apparatus (10) mountable on a rotatable axle of a vehicle, the track apparatus comprising: a continuous flexible track (15) having a main inner surface (28) and spaced track lugs (32) projecting therefrom, each track lug (32) terminating in a distal surface (32a) spaced inwardly from the main inner surface; and • a drive wheel (12) mountable on the axle for driving the flexible track about the axle, the drive wheel including a central hub (52), a radially-extending portion extending radially from the central hub and terminating at a radially outer edge, and an outer rim (24) connected with the outer edge, the outer rim (24) having lug-engagement surfaces (29), whereby the track lugs (32) are received in lug-receiving gaps which are formed between corresponding pairs of drive members (30) projecting from the lug-engagement surfaces (29) of the outer rim (24) of the drive wheel (12), such that the major extent of the axial widths of the distal surfaces (32a) of the track lugs (32) engage the lug-engagement surfaces (29) of the outer rim (24) of the drive wheel in order that the lugs (32) are supported when driven by the drive wheel, thereby to minimize damage to the lugs (32) during operation of the track system. 2. The track apparatus as claimed in claim 1 wherein the drive wheel is free of side structure in positions which are laterally adjacent to the lug-engagement surfaces and radially beyond the outer edge, whereby the track lugs (32) are free to adjust their precise positions of engagement with the lug-engagement surfaces. Dated this 10.04.2002 [VARUN SHARMA] OF REMFRY & SAGAR ATTORNEY FOR THE APPLICANTS

Documents:

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in-pct-2002-00443-mum-abstract(11-07-2008).doc

in-pct-2002-00443-mum-abstract(11-07-2008).pdf

in-pct-2002-00443-mum-cancelled page(11-07-2008).pdf

in-pct-2002-00443-mum-claim(granted)-(11-07-2008).doc

in-pct-2002-00443-mum-claim(granted)-(11-07-2008).pdf

in-pct-2002-00443-mum-correspondence(14-07-2008).pdf

in-pct-2002-00443-mum-correspondence(ipo)-(31-07-2008).pdf

in-pct-2002-00443-mum-drawing(11-07-2008).pdf

in-pct-2002-00443-mum-form 1(10-04-2002).pdf

in-pct-2002-00443-mum-form 18(02-08-2005).pdf

in-pct-2002-00443-mum-form 2(granted)-(11-07-2008).doc

in-pct-2002-00443-mum-form 2(granted)-(11-07-2008).pdf

in-pct-2002-00443-mum-form 3(10-04-2002).pdf

in-pct-2002-00443-mum-form 3(11-07-2008).pdf

in-pct-2002-00443-mum-form 3(14-07-2008).pdf

in-pct-2002-00443-mum-form 5(11-07-2008).pdf

in-pct-2002-00443-mum-form-pct-isa-210(16-04-2002).pdf

in-pct-2002-00443-mum-petition under rule 137(11-07-2008).pdf

in-pct-2002-00443-mum-petition under rule 138(11-07-2008).pdf

in-pct-2002-00443-mum-petition under rule 138(20-06-2007).pdf

in-pct-2002-00443-mum-power of authority(11-07-2008).pdf

in-pct-2002-00443-mum-power of authority(16-04-2002).pdf