US20150048671A1 - Apparatus for converting a wheeled vehicle to a tracked vehicle - Google Patents

Abstract

The invention relates to a self-propelled, wheeled vehicle that may be converted into a multi-track self-propelled vehicle using one or more track assemblies. Each track assembly includes a carriage with a main frame that support forward and rearward idler wheels and a plurality of centrally located, inner bogey wheels, and an outrigger beam that supports a plurality of centrally located, outer bogey wheels. One of the idler wheels is movably connected to the main frame and is movable by an actuator. The carriage is removably connected to a spindle of a vehicle by an attachment assembly. The attachment assembly includes a first or lower section and a second or upper section that generally encircle a portion of the spindle housing, and which are connected thereto by a plurality of fastening elements. A sprocket is operatively connected to a wheel hub of the spindle either directly or indirectly by way of a spacer element. A flexible endless track is entrained about the idler wheels, the bogey wheels and the sprocket.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 13/794,634, filed Mar. 11, 2013, which is a continuation of U.S. patent application Ser. No. 13/590,606, filed Aug. 21, 2012, now abandoned, which is a continuation of U.S. patent application Ser. No. 12/330,689, filed Dec. 9, 2008, now U.S. Pat. No. 8,245,800, which applications are hereby incorporated by reference in their entireties.
FIELD OF THE INVENTION
• This application relates to wheeled vehicle to a tracked vehicle. More specifically, this application relates to track assemblies that may be used to convert a self-propelled tire or wheel supported vehicle to self-propelled multi-track vehicle.
BACKGROUND
• Self-propelled, wheeled, multi-purpose vehicles are old and well known in the art. Such vehicles were originally designed to perform a variety of tasks that were commonly handled by cranes, hoists, tractors, trailers, and other specialized equipment. Such vehicles most often take the form of a steerable, wheeled chassis that is equipped with a boom that can be raised, extended and/or retracted. The end of the boom may be provided with one or more attachments, such as a pallet fork, a basket, bucket, etc. as the situation arises. These vehicles are typically used at construction sites and/or other off-road areas, where the ground upon which they traverse has not been surfaced or otherwise prepared. Often, the ground is not capable of supporting the weight of the self-propelled tire or wheel supported and they can become mired and/or lose traction. If the vehicle becomes mired or stuck, it is unable to be productive. If the vehicle cannot be extricated by the driver, additional equipment and personnel will have to be drawn away from other projects to provide assistance. If a vehicle was carrying a load at the time, the remedy becomes more complicated. Loads can shift and fall. In addition, a repositioned load can change the location of the center of gravity so that it and the vehicle are in an unstable position.
• It will be appreciated from the foregoing, therefore, that prior art self-propelled wheeled vehicles present problems that are in need of solutions and there is a need for a vehicle that is able to be used in conditions that would not otherwise be possible.
SUMMARY
• In a preferred embodiment, an apparatus converts a wheeled vehicle to a tracked vehicle. The apparatus includes a track system that is configured and arranged to be attached to existing wheel hubs of a vehicle such as construction equipment, preferably telehandlers and boom lifts. The track assembly unit includes a carriage having a main frame, a pair of struts that extend transversely from one side of the main frame, and an outrigger beam that is attached to the ends of the struts. A plurality of wheels is rotatably mounted to the carriage. More specifically, a first idler wheel is mounted at a first end of the carriage and a second idler wheel is mounted at a second end of the carriage. One of the idler wheels may be adjustably mounted to the carriage so that the tension on an endless track can be varied. The carriage includes two sets of bogey wheels that are located between the rotational axes of the idler wheels. One set of bogey wheels are mounted on the main frame and the other set of bogey wheels are mounted on the outrigger beam. The main frame includes a sleeve that extends transversely to the longitudinal axis of the main frame, with the sleeve having an interior configured to receive a pin that is used to connect the carriage to an attachment assembly.
• A preferred embodiment of the attachment assembly includes first and second (or lower and upper) sections that can be attached to a vehicle axle, more specifically, the spindle housing of a vehicle axle. The lower and upper sections of the attachment assembly can be connected to existing lower and upper trunnions, respectively. The lower and upper sections of the attachment assembly include inner edges that are able to contact the outer surface of the spindle housing. The lower section of the attachment assembly includes a pair of downwardly extending flanges, each of which includes a transverse aperture, with the transverse apertures able to receive a pin used to connect the lower section to a main frame of the carriage. The flanges of the lower section enable the wheels of the carriage to be positioned below the wheel hub of a vehicle. In addition, the flanges position the lower section below the spindle housing so that the carriage is able to rotate about the pivot pin connection. More specifically, the lower section includes forward and rearward extending wings that extend away from each other in upwardly divergent directions. The bottom surfaces of the wings are configured and arranged so as to be able to contact front and rear portions of the main frame of a carriage as it pivots back and forth. The angle of rotation is on the order of plus or minus 10-15 degrees, relative to the lower attachment section. The track assembly of the present invention may include one or more limiter bars or stop plates that are attached to the lower section of the attachment assembly. In use, the limiter bars or stops can modify or otherwise restrict the available angle of rotation between the carriage and the lower section of the attachment assembly.
• In a preferred embodiment, the adjustable idler wheel of the carriage is mounted at the front end of the main frame and it is operatively connected to a tensioning apparatus or mechanism. More specifically, the idler wheel is rotatably attached to a shaft that is connected to one end of a pivot arm. The other end of the pivot arm is rotatably mounted to a transversely oriented strut that extends through the main frame. A tensioning mechanism is operatively connected to the pivot arm and the main frame and includes an expandable/retractable force exerting member such as a grease cylinder, hydraulic cylinder, spring element, or the like. In use, the force exerting member rotates the pivot arm about the strut, in backward and forward motion that raises and lowers the idler wheel. The tensioning mechanism is able to absorb impacts when the tracked vehicle encounters an object on the ground while in operation. For example, when the front end of the track assembly encounters an immovable object in the tracked vehicle's path, the forwardmost idler wheel will tend to be pushed upwardly and to a lesser extent, rearwardly and the force exerting member will be momentarily compressed. In the absence of the immovable object, the force exerting member will both urge the forwardmost idler back to its normal operating position.
• The apparatus of this application includes a sprocket that can be attached directly to a wheel hub or to a spacer element that is interposed between the wheel hub and the sprocket. The sprocket includes a plurality of circumferential apertures that are configured and arranged to engage projections that extend inwardly from an inner surface of an endless track. As will be appreciated, other sprockets with different track engaging surfaces may be used, dependent upon the particular endless track configuration used in the track assembly. For example, a sprocket may have radially extending teeth that engage apertures in an endless track.
• The track assemblies can be used to convert a wheeled vehicle into a tracked vehicle. They provided a simplified track tensioning mechanism, and can be easily accessed, serviced and/or replaced.
• The track assemblies can be attached to a vehicle without having to make any modifications to the vehicle.
• An advantage of the track assemblies is that a portion of the assembly can be connected to an axle and the remainder of the track assembly removed or attached as desired.
• Another advantage is that the track assemblies may be attached to a wide variety of vehicles.
• These and other objectives, features and advantages will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. And, although the disclosure hereof is detailed and exact, the physical embodiments herein disclosed are merely examples that may be embodied in other specific structures. While preferred embodiments have been described, the details may be changed without departing from the claims.
DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a side elevational view of a known, prior art wheeled vehicle;
• FIG. 2 is the vehicle ofFIG. 1 in which the support wheels have been removed and the vehicle has been modified with one or more track assembly units;
• FIG. 3 is a perspective view of a front axle of a vehicle that has been partially modified with a track assembly unit, the view looking down from the in front of and to the right of the axle;
• FIG. 4 is a partial, exploded view ofFIG. 3;
• FIG. 5 is a perspective view of the attachment assembly and spindle housing, the view from behind and inboard from the spindle housing;
• FIG. 6 is a partial, inboard view of the carriage connected to the attachment assembly ofFIG. 5;
• FIG. 7 is an outboard side elevational view of a carriage;
• FIG. 8 is an inboard side elevation view of the carriage ofFIG. 7;
• FIG. 9 is a top plan view of the carriage ofFIG. 7;
• FIG. 10 is a bottom plan view of the carriage ofFIG. 7;
• FIG. 11 is rear elevational view of the carriage ofFIG. 7;
• FIG. 12 is a front elevational view of the carriage ofFIG. 7; and,
• FIG. 13 is a partial, exploded, perspective view of the carriage ofFIG. 7.
DETAILED DESCRIPTION
• Referring initially toFIG. 1, a side elevation of a known prior art self-propelled,wheeled vehicle10 is shown. The typicalprior art vehicle10 generally comprises a chassis11 that has abody12, driver controls13, and a motive source that is used to supply power to a plurality of wheels ortires16, some of which may be steerable. The motive source is also generally used to supply power to aboom14 so that it may be raised and lowered, rotated, and extended/retracted. The end of theboom14 is generally provided with a multi-functional workingend15, but it may also be provided with specialized tools and/or attachments, as needed. Each wheel ortire16 is attached to a conventional,flanged wheel hub52, which is connected to an axle40 (seeFIG. 3). Referring toFIG. 2, thewheels16 of aprior art vehicle10 ofFIG. 1 have been removed and replaced withtrack assemblies20. As will be discussed in greater detail below, eachtrack assembly20 generally includes awheeled carriage22, anattachment assembly24, aspacer element26, asprocket28, and anendless track34.
• Now referring toFIG. 3, anaxle40 of the type that can be used with a pair of track assemblies. Each end of thedrive axle40 includes an axle housing with ayoke42 and a spindle housing with ayoke44. Theaxle housing yoke42 and thespindle yoke44 are rotatably connected to each other by lower andupper trunnions46,47. Eachspindle housing44 includes aknuckle48 that extends from the exterior and which is connected to asteering arm50. Thedrive axle40 also includes drive shafts (not shown) that are connected via universal joints (not shown) towheel hubs52. As shown, a wheel16 (shown in phantom) is attached to awheel hub52 of the type having aflange54 and fastening elements, such as threadedstuds56 and nuts58. The right front wheel has been replaced by atrack assembly20 that includes acarriage22 with support wheels, asprocket28 and anendless track34 having aninterior surface36, anexterior surface38 and inwardly extendingprojections39. The endless track also includes a second set of inwardly extending projections (not shown) that are configured to be engaged by the sprocket.
• Note that thecarriage22 is positioned below and in substantial alignment with thewheel hub52 and the carriage is cantilevered outwardly relative to theattachment assembly24. Note that because theattachment assembly24 does not interfere with the operation of thewheel hub52, it need not be removed. This permits a user to connect one or more attachment assemblies to a vehicle and switch between wheels and tracks, as needed or required. In addition, it is envisioned that the attachment assemblies can have separate utility. For example, they could be used as anchor points to tie a machine to a structure such as a transport trailer. They could also be used as attachment points for other transport devices such as skis.
• A partially exploded view of the major components of thetrack assembly20 can be seen inFIG. 4. Here, theendless track34 has been omitted for clarity. Beginning with right front end ofaxle40, the attachment assembly comprising lower60 and upper62 sections, is positioned below and above thespindle housing44. As will be discussed later in greater detail, thelower section60 of theattachment assembly24 has a plurality of stanchions withinner edges96 that closely match the contours of a portion of the exterior surface of thespindle housing44 about which it is positioned. Thelower section60 may be connected to alower trunnion46 using existingtrunnion bolts107. To install, existingtrunnion bolts107 are removed, thelower section60 of theattachment assembly24 is positioned onto thespindle housing44 from below, and thetrunnion bolts107 are inserted throughapertures106 in thelower section60 and tightened.
• Theupper section62 of theattachment assembly24 is generally arcuately shaped and has an internal orinner edge144 that closely matches the contours of a portion of the exterior surface of thespindle housing44 about which it is positioned. As will be discussed later in greater detail, theupper section62 may be connected to anupper trunnion47. To install, existingtrunnion bolts168 are removed, theupper section62 of theattachment assembly24 is positioned onto thespindle housing44 from above, and thetrunnion bolts168 are inserted through apertures166 in theupper section62 and tightened.
• The lower andupper sections60,62 of theattachment assembly24 are secured to each other bytransverse fastening elements158,159 such as threaded nuts and bolts. An important feature of thelower section60 is the parallel, downwardly extendingflanges110,112. As will be discussed below in greater detail, theflanges110,112 are sized to receive amain frame180 of acarriage22 therebetween.
• Moving towards the left of thewheel hub52, there is a ring-shapedspacer element26 and asprocket28 comprisingsegments30 and32. Thespacer element26 may be interposed betweenwheel hub flange54 and thesprocket28, if needed. Thespacer element26 is used to connect thetrack assembly20 to the existingwheel hub52 of a vehicle. To that end, thespacer element26 includes a first set of apertures27A that correspond to thefastening elements56,58 of the wheel hub52 a vehicle, and a set of outwardly extending, peripheral fastening elements27B, such as threaded studs27B and nuts27C, that correspond to apertures to thesprocket28 of the track assembly. As will be understood, the apertures27A and fastening elements27B may differ in terms of numbers and patterns, depending upon the particular vehicle to which a track system is to be attached and the particular type of sprocket is being used. Alternatively, the spacer element may be integrally formed with the sprocket or sprocket segments. As will be appreciated, the particular sprocket used with the attachment assembly may vary. For example, the sprocket may include outwardly extending teeth that engage apertures in an endless track. Alternatively, the sprocket may include peripheral apertures that engage projections that extend inwardly from an endless track.
• Apreferred sprocket28 comprises twosprocket segments30,32, with eachsprocket segment30,32 comprising an arcuately shaped plate having inner and outer circumferences. A plurality of bars is evenly spaced about the outer circumference in a transverse orientation and the ends of the bars are connected by side walls or rims. The bars and side walls define openings or gaps that receive and engage inwardly extending projections37 of aflexible track34. The plate also includes a plurality of slots or apertures spaced evenly about and adjacent to the inner circumference, with the slots or apertures configured to be aligned with the threaded studs that extend from either thespacer element26 or thewheel hub52.
• A partially exploded perspective view of theattachment assembly24 and aspindle housing44, with the view taken from the rear and inside looking towards the front and right is depicted inFIG. 5. An inboard elevational view of thecarriage22 and theattachment assembly24 connected thereto, is depicted inFIG. 6. Note, inFIG. 6, that thespindle housing44, to which theattachment assembly24 would be connected, has been omitted to facilitate a better understanding of the invention. In a preferred embodiment, theattachment assembly24 comprises two components, a first orlower section60, and a second orupper section62. The first orlower section60 comprises a body orbase64 having anupper surface66 and alower surface68, opposing forward and rearward ends70,72, opposing sides and a center section. An extension orwing82,84 is connected at eachend70,72, preferably at an angle, so that the wings project forwardly and rearwardly from thebody64 in divergent, ascending directions. Thewings82,84 are configured and arranged to engage thetop surface250 of thetop wall192 ofmain frame180. This allows themain frame180 to pivot back and forth as the track assembly traverses a non-planar surface.
• A plurality of spaced-apart stanchions orposts88,90,92,94 are attached to the front and rear extensions orwings82,84. Thestanchions88,90,92,94 are plate-like and their bases extend from the free ends of theextensions82,84 towards positions that are adjacent the center section of thebase64. All of thestanchions88,90,92,94 are generally vertically oriented and each stanchion or post88,90,92,94 includes an inwardly facing, generally arcuately shapedsurface96 that is configured to contact a portion of aspindle housing44. Note that the inwardly facingsurfaces96 of thestanchions88,90,92,94 need not have the same configuration becausespindle housings44 can have different exterior surface profiles. An upper, free end of eachstanchion88,90,92,94 includes atransverse aperture98,100,102,104 that is configured to receive afastening element158 used to connect the first orlower section60 to a second orupper section62 of theattachment assembly24. The stanchions orposts88,90,92,94 and the body orbase64 form a cradle-like structure that receives a lower portion of avehicle spindle44.
• The first orlower section60 of theattachment assembly24 is removably connected to a bottom portion of aspindle44 of a vehicle by way of fastening elements, more specifically, thefastening element107 that are normally used in alower trunnion46. To attach thelower section60 to aspindle housing44, thefastening elements107 of thelower trunnion46 are temporarily removed, thelower section60 of theattachment assembly24 will be moved into position from below, and thefastening elements107 are inserted intosmall apertures106 in the center section of the base orbody64, which are in alignment with the apertures in thelower trunnion46. The small apertures surround alarger aperture108 that serves as a relief for the trunnion pin itself.
• A pair of downwardly dependingflanges110,112 are connected to the sides of the body orbase64. A lower, free end of eachflange110,112 includes atransverse aperture114,116 that is configured to receive apivot pin276 that is used to connect theattachment assembly24 to thecarriage22. Theflanges110,112 position thebottom surface68 of the base orbody64 above thetop surface250 of themain frame180 of thecarriage22 so that the carriage can rotate with respect to theattachment assembly24. Thetrack assembly20 can rotate with respect to the axle40 (i.e., the range or degrees of rotational motion relative to the vehicle to which it is attached), up to approximately 25 degrees plus or minus; more, if desired. Optionally, limiter bars or stops122 may be attached to the bottom surfaces of thewings82,84 by fasteningelements123. As will be understood, the limiter bars or stops122 can change the amount of rotation that is available to thecarriage22.
• A preferred second orupper section62 of theattachment assembly24 includes an arcuatelyshaped body130 having a first orfront end134, a second or rear end136, side surfaces, an external edge, aninternal edge144, and atransverse plate160. The first and second ends134,136 are connected to thestanchions88,90,92,94 of the first orlower section60. The internal orinterior edge144 of theupper section62 includes an upwardly extendingslot146 and aside notch148. Theslot146 and thenotch148 provide relief for elements of thespindle housing44. Thetransverse plate160 is located at the uppermost portion of the internal orinterior edge144 and is generally horizontally oriented. Theplate160 includes a pair offlanges162,164 that extend outwardly from the sides of the upper section, with each flange including one or more vertically aligned apertures166 that are used to attach the upper section to avehicle spindle44. The second orupper section62 is removably connected to aspindle44 of a vehicle by way offastening elements168 that are normally used in aupper trunnion47. Thefastening elements168 of theupper trunnion47 are temporarily removed, theupper section62 is positioned from above onto thespindle housing44. Thefastening elements168 are inserted into the small apertures166, which are in alignment with theupper trunnion47 apertures, and tightened. The small apertures166 surround a larger aperture170 in thetransverse plate160 that serves as a relief for thetrunnion47.
• To facilitate connecting theupper section62 to thelower section60, eachend134,136 of theupper section62 is provided withtransverse apertures150,154, that receive transverse sleeves orbushings152,156. The sleeves orbushings152,156 at each end of thesection62 are positioned between correspondingstanchions88,90, and92,94 so that the apertures of thesleeves152,156 are aligned with thetransverse apertures98,100, and102,104 of thestanchions88,90,92,94. Fasteningelements158 are inserted into the aligned apertures of the lower andupper sections60,62 to secure them together. Theattachment assembly24 does not interfere with the normal operation of awheel15 and once an attachment assembly has been connected to avehicle axle40, it may remain there so as to enable a user to easily and rapidly convert a vehicle from a wheel drive to a track drive and vice-versa.
• After the attachment assembly has been connected to avehicle spindle housing44, thecarriage22 can be connected to theattachment assembly24 by positioning themain frame180 of the carriage between the downwardly dependingflanges110,112 of thelower section60 of the attachment assembly, aligning the transverse apertures of themain frame180 and the downwardly dependingflanges114,116, inserting thepivot pin276 through the aligned apertures and finally securing thepivot pin276 with aconventional fastening element278 such as a washer and a treaded bolt.
• Once thecarriage22 has been connected to thespindle44, thesprocket28 can be connected to the existingwheel hub52. As shown, aspacer element26 is interposed between the existingwheel hub52 and thesprocket28. Thespacer element26 is preferably in the form of a ring having a predetermined thickness defined by inner and outer surfaces and a width defined by an outside diameter and an inside diameter. The ring also includes a plurality of apertures or through holes27A that extend from the inner to the outer surfaces, and which are configured and arranged so that they are able to receive threadedstuds56 of an existingwheel hub52. In addition, the ring includes a plurality of threaded studs27B that are attached to and which extend away from the outer surface of the ring. The threaded studs27B are configured and arranged to operatively connect thesprocket28 by fastening elements27C. In operation, thespacer element26 is positioned over the threadedstuds56 of thewheel hub52 and secure thereto withfastening elements58 such as threaded nuts. Then, thesprocket28 is attached to the threaded studs27B of thespacer element26, again using fastening elements27C such as threaded nuts. As will be understood, thespacer element26 will position thesprocket28 so that it is brought into alignment with the idler318,376 andbogey wheels300,302,306,308 of thecarriage22. It is envisioned that thespacer element26 may be integrally formed with thesprocket28 itself, as a rearwardly extending flange, without departing from the spirit and scope of the invention.
• In a preferred method of assembly, thesprocket28 is attached to the spacer element26 (orwheel hub52 as the case may be) after theendless track34 is loosely fitted about thecarriage22. With the preferred method, afirst sprocket segment30 is connected to the bottom of the spacer element26 (or wheel hub52). Thewheel hub52 is then rotated so that thefirst sprocket segment30 moved to the apex of thecarriage22 assembly. Then, thesecond sprocket segment32 is connected to the spacer element26 (or wheel hub52). Finally, thetensioning apparatus330 is adjusted to remove residual slack in theendless track34. As will be noted, thetensioning apparatus330 allows thetrack assembly20 to accommodate similar endless tracks that may be fabricated by manufactures other than the original manufacturer, or endless tracks that may be different or which may have different applications than the original flexible, endless tracks.
• Apreferred carriage22 of atrack assembly unit20 is shown inFIGS. 7-13. Generally, thecarriage22 comprises amain frame180, anoutrigger beam290, and a plurality ofsupport wheels300,302,306,308,318 and376 that are rotatably attached to themain frame60 and the outrigger beam170. Themain frame180 comprises a first orinboard side wall188, a second oroutboard side wall190, atop wall192 and abottom wall194, with the inboard188, outboard190, top192, andbottom walls194 connected to each other to form an elongated structure. As best shown inFIG. 8, the first orinboard side wall188 is generally planar and has a first orexternal surface200, a secondinternal surface202, a first orforward end204 and a second orrearward end206. Aside wall188 includes anotch208 at thefirst end204, with thenotch208 providing access to a tensioning apparatus ormechanism330 to be discussed later. In addition,side wall188 includes a plurality of apertures that will be briefly discussed.Apertures210,212 that are configured to receive ends of transversely orientedstruts280,284, which will be discussed later. Anaperture214 and aslot215 are used in conjunction with the tensioning apparatus ormechanism330.Aperture216 is configured to receive an end of ashaft310 that supports anidler wheel318. Acutout218 is configured to receive asleeve272 and abushing274 that receive apivot pin276. And, twoapertures220 provide access to front and rearbogey wheel bolts245 and249.
• The second oroutboard side wall190 is similarly constructed, but with slight differences. As best shown inFIGS. 7,9,10 and13, the second oroutboard side wall190 is generally planar and has a first orexternal surface222, a secondinternal surface224, a first orforward end226 and a second orrearward end228. Aside wall190 includes anotch230 at thefirst end226, with thenotch230 providing access to a tensioning apparatus ormechanism330 to be discussed later. In addition,side wall190 includes a plurality of apertures that will be briefly discussed.Apertures232,234 that are configured to receive transversely orientedstruts280,284, which will be discussed later. Anaperture236 is used in conjunction with the tensioning apparatus ormechanism330. Aperture238 is configured to receive ashaft310 that supports anidler wheel318. Acutout240 is configured to receive asleeve272 and abushing274 that receive apivot pin276. And, tworecesses242,246 haveapertures244,248 that receiveshafts245,249 that rotatablysupport bogey wheels300,302.
• The first andsecond side walls188,190 are generally parallel to each other and connected at their upper and lower edges to top192 and bottom194 walls, respectively. As with the first and second side wall, the top andbottom walls192,194 each include a first orexterior surface250,260 and a second orinterior surface252,262. Together, theside188,190, top192, and bottom194 walls define an elongated structure, ormain frame180 having a first or forward end, a second or rearward end, and a middle section. Theaforementioned walls188,190,192,194 also form a generally polygonally shaped exterior and a generally hollow interior similar to a tube or tunnel.
• Turning toFIG. 9, the top orupper wall192 of themain frame180 includes a first orexternal surface250, a second orinternal surface252, a first orforward end254, and a second orrearward end256. As with the first andsecond side walls188,190, thetop wall192 includes anotch258 at its forward end that is used in conjunction with the tensioning apparatus ormechanism330. Thetop wall192 also includes atransverse slot159 that is in communication with thecircular cutouts218,240 on the first andsecond side walls188,190, respectively.
• The bottom orlower wall194 depicted inFIG. 10 is similarly constructed. That is to say, the bottom orlower wall194 includes a first orexternal surface260, a second orinternal surface262, a first orforward end264, and a second orrearward end268. Thebottom wall194 includes anotch270 at its first orforward end264 that is used in conjunction with the tensioning apparatus ormechanism330. Together, thenotches208,230,258,270 in the sides, top andbottom walls188,190,192,194 at the first or forward end of themain frame180 provide clearance and access space for the tensioning mechanism orapparatus330.
• Themain frame180 is provided with anoutrigger beam290 that is parallel to, and spaced from theexternal surface222 of the second oroutboard side wall190. Thebeam290 has a first end and a second end292,294 and a pair ofapertures296,298 that receive fastening elements or pins297,299 that are used to rotatably attach a pair ofouter bogey wheels306,308. The first and second ends292,294 of thebeam290 are connected to themain frame180 by first andsecond struts280,294. More particularly, the first andsecond struts280,284 have first and second ends, respectively, with the first ends of thestruts280,284 connected to theoutrigger beam290 and the second ends of the struts connected to themain frame180. Preferably, the second ends of the first andsecond struts280,284 extend through the second oroutboard side wall190 and to the first orinboard side wall188.
• As shown, thecarriage22 is provided with a plurality ofbogey wheels300,302,306,308, with each bogey wheel having atrack contacting surface301,303,307,309 that rollingly engages theinner surface36 ofendless track34. Generally, there are two sets of inner300,302 andouter bogey wheels306,308. As mentioned above, theinner bogey wheels300,302 are rotatably connected to theoutboard side wall190 of themain frame180 by way of fastening elements such as shafts or pins245,249. Preferably thewheels300,302 are located between thestruts280,284 and preferably at circularly shapedrecesses242,246. The outer or outboard set ofbogey wheels306,308 are rotatably connected to theoutrigger beam290 by way of fastening elements such as shafts or pins297,299, also preferably between thestruts280,284 and preferably at an inner side of thebeam290. Optionally, thebeam290 may be provided with a strengthening washers for eachbogey wheel306,308 attachment. As shown, the inner andouter bogey wheels300,302,306,308 are spaced apart from each other and define a space through which both portions of adrive sprocket28 and projections of anendless track34 may pass unencumbered. Preferably, the distance between the rotational axes of theinner bogey wheels300,302 is greater than the distance between the rotational axes of theouter bogey wheels306,308. Although the preferred number of bogey wheels per set is two, it is understood that each set could have more or less than two bogey wheels without departing from the spirit and scope of the invention.
• Moving towards the rear of thecarriage22, and as best shown inFIGS. 9,10,11, and13 thecarriage22 is provided with ashaft310 that extends outwardly from theoutboard side wall190 of themain frame180, and which is substantially parallel to the first andsecond struts280,284. As with the previously describedstruts280,284, theshaft310 has first and second ends, with the second end of the shaft extending through the second oroutboard side wall190 and intoaperture216 of first orinboard side wall188. Arear hub assembly312, which includes aflange314 with a plurality of mountingapertures316, is rotatably mounted onshaft310. Arear idler wheel318 is attached to therear hub assembly312 usingconventional fastening elements319 such as threaded bolts. Therear idler wheel318 includes an innertrack contacting surface320, an outertrack contacting surface322, and aguide channel324 located between the inner and outertrack contacting surfaces320,322. As will be understood, theguide channel324 is configured and arranged to receive inwardly extending projections37 of anendless track34. Preferably, the inner and outertrack contacting surfaces320,322 of theidler wheel318 are in alignment with the inner and outer sets ofbogey wheels300,302,306,308, respectively.
• Continuing on towards the front of thecarriage22, as best shown inFIG. 13, a tensioning/shock absorbing apparatus ormechanism330 is connected to themain frame180 so that it is in alignment therewith. Generally, the tensioning/shock absorbing apparatus330 comprises apivot arm332 and an actuator ortensioning mechanism350, with thearm332 and theactuator350 configured to move afront idler wheel376. The pivot arm orarm332 comprises a generally rectangularly shaped body having a width, a thickness and length. More specifically, the first end of thearm332 is provided with anaperture338 that receives an end of ashaft370, and which is secured to the arm by afastening element371. Theshaft370 rotatably supports afront hub assembly372 that includes aflange374 with a plurality of mountingapertures375. A first or frontidler wheel376 is attached to thefront hub assembly372 usingconventional fastening elements377 such as threaded bolts. The first or frontidler wheel376 includes an innertrack contacting surface378, an outertrack contacting surface380, and aguide channel382 located between the inner and outertrack contacting surfaces378,380. As will be understood, theguide channel382 is configured and arranged to receive inwardly extending projections37 of anendless track34. Preferably, the inner and outertrack contacting surfaces378,380 of theidler wheel376 are in alignment with the inner and outer sets ofbogey wheels300,302,306,308, respectively.
• The second end of thepivot arm332 has a width that is less than the distance between theinterior surfaces202,224 of the inboard and outboardvertical side walls188,190. Thesecond end206 of thepivot arm332 includes abed340 and aremovable cap342 that may be attached thereto by fasteningelements343 such as threaded screws. Preferably, thebed340 and thecap342 have arcuately shaped surfaces that complement each other so that thepivot arm332 may be connected to the portion of the first orforward strut280 that extends between the outboard andinboard side walls190,188 of themain frame180. Preferably, a bushing or bearingmaterial344 is interposed between thecap342 and the bed340 (of the pivot arm332), and thefirst strut280, so that thepivot arm332 may rotate with less friction.
• A preferred actuator ortensioning mechanism350 generally comprises an elongated body having first and second ends, which can be extended and retracted relative to each other. Theactuator350 comprises ahousing356 and apiston362 that is telescopically received in thehousing356 and which is movable relative thereto under the influence of internal pressure. The free end of thehousing356 is provided with a transversely orientedpineye mount358. Thepineye mount358, which has a length that is less than the distance between theinner surfaces224,202 of the outboard andinboard side walls190,188 of themain frame180, is configured to be received within the main frame and rotatably secured thereto withfastening element360 such as a threaded bolt and nut. The free end of thepiston362 is also provided with a transversely orientedpineye mount364, which is rotatably connected to a pair offlanges246,248 that extend from theupper surface345 ofpivot arm332. The actuator ortensioning mechanism350 is located above thepivot arm332. When the actuator ortensioning mechanism350 is extend, thepivot arm332 will be rotated downwardly and when the actuator or tensioning mechanism is retracted, the pivot arm will be rotated upwardly. This changes the location of the first or forwardidler wheel376, and hence the total circumference about which anendless track34 is engirded. Equally important, the actuator ortensioning mechanism350 can act as a shock absorber for the first or frontidler wheel376. Preferably, theactuator350 is a grease cylinder having agrease fitting368 that extends through theslot215 in the inboard or firstvertical wall188 of themain frame180. However, it will be understood that other actuators may be used without departing from the spirit and scope of the invention. For example, the actuator or tensioning mechanism could be a hydraulic cylinder, a pneumatic cylinder, one or more spring elements, or the like.
• The foregoing is considered as illustrative only. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, the exact construction and operation shown and described is only an example of a preferred embodiment. The invention is defined by the following claims.

Claims (1)

What is claimed is:

1. A track assembly for use with a vehicle having a spindle housing and an axle hub, the track assembly comprising:

an attachment assembly configured to be connected to the spindle housing of the vehicle;

a carriage that pivotally connects to the attachment assembly, the carriage including a main frame having a first end and a second end;

a track driven about a generally triangular path;

wherein the carriage pivots relative to the attachment assembly about a pivot axis that extends in an inboard to outboard orientation, wherein the attachment assembly includes a first stop that engages the main frame to limit rotation of the carriage about the pivot axis in a first direction, and wherein the attachment assembly includes a second stop that engages the main frame to limit rotation of the carriage about the pivot axis in a second direction.

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