Abstract: A drive wheel for a track system having an endless track that has first, second, and third drive wheel engagers is disclosed. The drive wheel has a hub, a body, a rim, a plurality of first, second and third track engagers radially disposed on the rim. Each of the plurality of second track engagers are operationally aligned with one of the plurality of first track engagers. The plurality of third track engagers are on at least one lateral side of the plurality of first track engagers. The plurality of first, second and third track engagers are configured to, respectively, driveably engage with a first, second, and third drive wheel engagers of the endless track. An endless track and a track system are also disclosed.

Abstract: A track chain member includes a shoe member, and a first rail member extending from the shoe member. The first rail member includes a first lug defining a first bore defining a first longitudinal axis and including a first bushing retention shelf disposed in the first bore, as well as a second lug including a second bushing retention shelf disposed in the second bore. A third lug extends in a direction opposite that of the first lug and second lug and is disposed axially between the first lug and the second lug.

Abstract: A track link assembly comprises a plurality of link subassemblies. Each link subassembly may include a pair of links coupled together. Each link may include a first aperture and a second aperture, and the second aperture of each link may be larger than the first aperture. The track link assembly may include a pin element extending through the first aperture of a first link and the second aperture of a second link in each link subassembly. The track link assembly may include a bushing element with a central opening. The bushing element may surround a portion of the pin element and extend through the second aperture of the second link of each link subassembly. The bushing element may include at least one hole configured to couple a track shoe to the bushing element.

Abstract: A track tension device and a track moving device are provided. The track tension device includes an upper transmission belt, a lower transmission belt, an upper tension portion, a lower compression portion and a resilient support portion. The track moving device includes the track tension device.

Abstract: A sprocket wheel and drive track assembly of a tracked vehicle includes at least one drive sprocket having a sprocket wheel. A plurality of internal teeth extending laterally therefrom is distributed in a circumferential direction on a periphery thereof at a sprocket pitch from each other. A belt in contact with the at least one drive sprocket has an inner side, an outer side, a longitudinal and a lateral direction. At least two of a plurality of internal lugs distributed on the inner side thereof are engaged by at least two of the plurality of internal teeth of the at least one drive sprocket. The plurality of internal lugs is disposed to form at least one longitudinal row. At least two consecutive internal lugs are disposed at a first pitch from each other. The first pitch is longer than an arc length corresponding to the sprocket pitch.

Abstract: A vehicle track-module including an upper drive wheel, a plurality of idler and bogey wheels, and an endless rubber track with spaced lugs which extends around the wheels and is driven by the drive wheel, which has: a middle main plate with a outer edge of first diameter and inward and outward sides forming the exposed inward and outward surfaces of the drive wheel; drive members axially across and projecting radially beyond the main-plate edge to a second diameter, each drive member having axially inward and outward end portions, a middle portion affixed at its middle position to the main-plate edge, and an outer track-engaging surface; and a rigidity ring affixed to the inward end portions of the drive members and having an inner diameter no less than half the first diameter and an outer diameter no greater than the second diameter. In some embodiments, the axial dimension of the track-engaging surfaces of the drive members is at least 50% greater than the axial dimension of the track lugs.

Abstract: A drive track of a tracked vehicle includes a belt having an inner side and an outer side. The belt has a longitudinal direction and a lateral direction. The inner side has a plurality of internal lugs forming at least one longitudinal row. The outer side has a plurality of external lugs forming a plurality of lateral rows. The plurality of lateral rows is disposed at a first pitch from each other. The plurality of internal lugs of the at least one longitudinal row is disposed so as to form a repeating sequence where some consecutive internal lugs are disposed at a second pitch from each other, and other consecutive internal lugs are disposed at a third pitch from each other. The second pitch is smaller than at least one of the first pitch and the third pitch. A sprocket wheel and drive track assembly is also presented.

Abstract: A tensioning system for a tracked vehicle. The present invention provides for adjusting tension of a track by moving the sprocket relative to the rollers in a substantially vertical direction. The system comprises a sprocket assembly, a roller assembly, a track, and a tension adjustment assembly. The tension adjustment assembly includes a tension bolt threaded through a tension nut. The bolt threads through the nut and contacts the roller assembly. As the bolt is threaded or unthreaded, the sprocket assembly is moved relative to the roller assembly in a substantially vertical direction. As the assemblies move relative to each other, tension in the track is resultantly adjusted.

Abstract: This invention describes a track guide, used with endless tracks mounted over tires of off-road vehicles, preventing laterally rolling off the inner or outer surfaces of the drive tires. The track guide counteracts, grips and controls the lateral slippage of the endless track dislodging from the drive tires, caused by conditions such as tensioned forces, sharp power-on turns in snow, ice, mud, sand and all other situations. The track guide effectively improves the ride and maneuverability of off road vehicles.

Abstract: A tensioning system for a tracked vehicle. The present invention provides for adjusting tension of a track by moving the sprocket relative to the rollers in a substantially vertical direction. The system comprises a sprocket assembly, a roller assembly, a track, and a tension adjustment assembly. The tension adjustment assembly includes a tension bolt threaded through a tension nut that is secured to the sprocket assembly. The bolt threads through the nut and contacts the roller assembly. As the bolt is threaded or unthreaded, the sprocket assembly is moved relative to the roller assembly in a substantially vertical direction. As the assemblies move relative to each other, tension in the track is resultantly adjusted.

Abstract: A track assembly having a drive sprocket capable of concentrically supporting several detachable drive rings containing drive teeth shaped to rotate without interfering with track support idler wheels, to provide a reduced center of gravity and substantially provide the same vehicle operating characteristic with tracks as with wheels. A track retainer guide member mounts along a peripheral edge of the track and overlies the track to resist track dislodgement. Independent and/or resiliently biased, rocker arms support track idler wheels to induce track flexion and conformance to encountered obstructions.

Abstract: A combination of a drive tumbler and a track includes a track made of a plurality of connected track shoes and a plurality of driven surfaces. The track is wrapped around the drive tumbler so that a plurality of the shoes are in contact with the drive tumbler. The drive tumbler has a plurality of drive surfaces and a circumferential rim surface that includes a plurality of shoe contact surfaces that each contact the inside surface of one of the track shoes that are in contact with the tumbler. The shoe contact surface has a shape such that a line normal to the tangent of the shoe contact surface does not pass through the axis of rotation of the drive tumbler, thereby allowing the shoe contact surfaces on the rim of the drive tumbler to transmit a tractive force to the track. A preferred drive tumbler comprises a center hub and a plurality of individual tooth members connected to the center hub by welds.

Abstract: A track chain joint for an endless track chain of a track-type vehicle is configured to engage first and second sprockets of a drive wheel of the track-type vehicle. Exemplarily, the joint has a pin, a bushing on the pin, first and second collars positioned respectively axially outboard of the bushing on the pin, and first and second drive caps positioned respectively axially outboard of the first and second collars and fixed to the pin, the first and second drive caps configured to engage respectively the first and second sprockets. Such components may be embodied in a cartridge.

Abstract: A sprocket assembly for a track-type machine comprises a plurality of teeth, radially-disposed about a center of the sprocket assembly, each of the plurality of teeth comprising opposing tooth flanks, wherein successive pairs of teeth defines a substantially concave channel for receiving therein a cylindrical pin member associated with a track link member of a continuous track chain, each tooth flank having a tooth angle less than about 17 degrees.

Abstract: A caster of an endless structure is provided which is almost jam-proof even in the case of a bigger gap. The caster includes a first wheel supported on a mounting leg, a second wheel supported by an axle on one end of a suspension arm of which the other end is supported by an axle which also supports the first wheel, and a wrap-around member which is wrapped around the first and second wheels. The wraparound member is formed an endless belt form by connecting independent pieces to each other. The outer peripheral section of each piece is provided with a wider section and when the wraparound member is depressed and warps, the wider section is adapted to touch a wider section of the adjacent piece, thereby preventing further depression.

Abstract: An elastomeric endless track for use on tracked vehicles or with wheel replacing traction assemblies is provided. The track generally comprises a ground-engaging outer surface provided with traction lugs generally disposed longitudinally according to a traction lug pitch, and a wheel-engaging inner surface provided with drive lugs disposed longitudinally according to a drive lug pitch and guide lugs disposed longitudinally according to a guide lug pitch. Such a track comprises the feature of having the guide lug pitch and/or the length of the guide lugs chosen so as to reduce the distance between consecutive guide lugs in order to reduce and/or prevent occurrences of detracking.

Abstract: A sprocket used to transmit drive force to a coreless crawler track having rubber projections arranged at predetermined intervals on the inner peripheral surface of the crawler track. The sprocket has, on its circumferential edge, sprocket teeth arranged at the same pitch as the rubber projections. A cutout is formed at the outer circumferential tip of each sprocket tooth. Even if meshing between the rubber projections and the sprocket teeth has a trouble caused by the entry of soil and sands, the rubber projections are affected less, which greatly contributes to improvement of durability of the crawler track.

Abstract: A sprocketed idler for a machine comprises a plurality of teeth radially disposed about an idler having a substantially circular cross section. Each of the plurality of teeth includes at least one tooth flank having a substantially uniform slope, wherein a distance between adjacent peaks of the plurality of teeth is between 30% and 90% of the distance between central axes of adjacent pin members of a track link that is engageable by the idler.

Abstract: A robotic vehicle is disclosed, which is characterized by high mobility, adaptability, and the capability of being remotely controlled in hazardous environments. The robotic vehicle includes a chassis having front and rear ends and supported on right and left driven tracks. Right and left elongated flippers are disposed on corresponding sides of the chassis and operable to pivot. A linkage connects a payload deck, configured to support a removable functional payload, to the chassis. The linkage has a first end rotatably connected to the chassis at a first pivot, and a second end rotatably connected to the deck at a second pivot. Both of the first and second pivots include independently controllable pivot drivers operable to rotatably position their corresponding pivots to control both fore-aft position and pitch orientation of the payload deck with respect to the chassis.

Abstract: An endless track chairs for use with a track-type vehicle comprises a cartridge joined to the links of first and second link sets for relative rotation between the link sets.

Abstract: An enhanced traction device for use with a vehicle having dual tandem wheels includes a series of generally parallel track pads, each track pad having an alignment portion and a traction portion defining first and second ends. Each traction portion includes an inner surface for contacting the vehicle wheels and an outer surface for contacting ground. Each alignment portion extends away from a respective traction portion outer surface and is configured to pass between the dual wheels. The alignment portions maintain proper positioning of the track pads upon the dual tandem wheels of the vehicle. The traction device further includes a first chain coupled to each respective track pad first end for maintaining a predetermined spacing between said track pad first ends. Similarly, the traction device includes a second chain coupled to each track pad second end for maintaining a predetermined spacing between the track pad second ends.

Abstract: A rubber track having increased durability achieved by reducing teeth skipping phenomenon occurring between a sprocket at the vertex of a triangular chassis portion and rubber projections of the rubber track is provided. The rubber track that is passed over a sprocket provided on a vehicle and idlers arranged on the left and right of the sprocket so as to form a triangular shape with the sprocket as the vertex and has rubber projections (22) raised on the center of the inner peripheral surface of the track, at predetermined intervals in a travel direction, wherein the rubber track satisfies the equation of C?A, with A the length of the rubber projections (22) in the lateral direction normal to the travel direction, C the pitch in the travel direction of the rubber projections.

Abstract: A track assembly having a drive sprocket capable of concentrically supporting several detachable drive rings containing drive teeth shaped to rotate without interfering with track support idler wheels, to provide a reduced center of gravity and substantially provide the same vehicle operating characteristic with tracks as with wheels. A track retainer guide member mounts along a peripheral edge of the track and overlies the track to resist track dislodgement. Independent and/or resiliently biased, rocker arms support track idler wheels to induce track flexion and conformance to encountered obstructions.

Abstract: A track assembly for a machine includes a track having inner track seals, a rotatable track engaging element such as an idler or drive sprocket and a contact interface for protecting the seals during guiding the track about the rotatable element. The contact interface may include sacrificial wear material on the rotatable element and sacrificial wear material on corresponding track links. The contact interface may have a configuration based on a location of the seals, and is adapted to inhibit wear of the track links in regions adjacent the seals. In another aspect, the contact interface is a guide interface.

Abstract: An offset track forms a pattern perpendicular to the centerline of the track which enables tracks to be formed with even or odd number of metal inserts and thus accommodate virtually any tracked vehicle. The offset track uses variations in body thickness and lug width to provide a high performance offset track with improved ride, minimum vibration and longer wear. Use of full size and mini-inserts in a single track minimizes the weight and further enhances the performance of an offset track.

Abstract: This invention relates to a sprocket wheel used with endless tracks used to propel heavy track laying vehicles [i.e., vehicles which use endless tracks rather than tires to contact the terrain over which they are driven, e.g., tractors, tanks, bulldozers, etc.] and, more particularly, to an improved polymer sprocket wheel allowing the endless track to be driven more efficiently at highway speeds.

Abstract: There is provided a crawler system and a crawler link structure which can be easily assembled and is superior in durability and provided at low cost. The crawler system comprises a crawler 2 in which pairs of opposed right and left links 1a and 1b are endlessly connected. One end of the pair of right and left links 1a and 1b are connected through a cylindrical connection part 3. Middle parts of the pair of right and left links 1a and 1b in the longitudinal direction are connected by an engaging part 4 which engages with a concave tooth 29 of concave-convex teeth 28 of a crawler sprocket 27. The pairs of right and left links 1a and 1b are endlessly connected by inserting connection pins 12 to the connection parts 3.

Abstract: A wheel for belted track vehicles includes a hub with an upright central disc. A series of individually cast and machined segments are mounted to the disc in side-by-side relation about the periphery of both sides of the disc. Each segment takes the shape of a truncated sector having a general “L” shape as viewed from an end, with a back or base engaging a side of the disc, and belt support elements extending laterally of the disc for engaging and supporting the track.

Abstract: A tracked vehicle produces a pressure no more than 3 psi on the ground by increasing the number of contact points on the inner surface of the track. The stiffness of the track is also selected to minimize bowing between the idler wheels or rollers. The track is therefore kept substantially straight between the rollers to increase the efficiency associated with transferring power to track. The drive sprocket is positioned above the ground so as to eliminate complexity in the design and yet effectively transmit power to the tracks. Positioning the drive sprocket above ground also prevents derailing of the track. The track is also held in a constant state of tension on the driver sprocket and the roller. This too prevents derailment. The undercarriage of the vehicle includes torsion axles and sealed bearings to provide for a lower maintenance track. Components associated with the undercarriage do not require constant greasing and cleaning of the idler wheels.

Abstract: A drive sprocket assembly for driving an endless chain assembly for propelling a machine has a hub portion and flexible cantilever teeth in which each tooth is separately deflectable upon impact by a bushing of the endless chain assembly. The flexibility of each tooth will absorb a portion of the kinetic energy of the impact to reduce noise in the structure. The drive sprocket assembly includes a plurality of segments each having the cantilever teeth. Each segment has a first end portion and a second end portion having an end relief which prevents wear between the segment and the hub as the end portion is deflected by the impact.

Abstract: A silent and reduced vibration chainwheel includes a disk, multiple teeth and an energy absorber. The disk has an outer edge, two opposite sides and at least one recess. The teeth are formed radially at and extend out from the outer edge of the disk. The energy absorber is made of resilient material and is mounted in the at least one recess at the outer edge of the disk to absorb the impact of a chain driven by or driving the chainwheel and reduce the noise and vibrations caused by the impact of the chain and the chainwheel. The energy absorber can be resilient annular rings, strips, rods or a combination of them. Therefore, the chainwheel is silent and fewer vibrations are produced so a person who uses a machine that has the chainwheel will feel comfortable.

Abstract: An elastic crawler has a crawler body formed like an endless belt out of an elastic material, a plurality of driving projections provided on an inner circumferential surface of the crawler body with a predetermined pitch in the circumferential direction thereof, and a plurality of traction lugs provided on an outer circumferential surface of the crawler body with a pitch different from that of the driving projections.

Abstract: A crawler traveling apparatus includes a rubber crawler belt having a plurality of driving projections formed with a predetermined peripheral pitch on an inner peripheral face of the belt, a drive wheel rotatable when engaged with the driving projections of the crawler belt for driving the belt, and a plurality of free wheels rotatable for laterally guiding the driving projections under movement. Each driving projection has an upper half having a lateral face including an upper half lateral face portion and a lower half having a lower half lateral face portion, the upper half lateral face portion having an erect inclination angle smaller than an erect inclination angle of the lower half lateral face portion. Each free wheel has an inner lateral face opposed to the driving projection, the inner lateral face having an inclined guide face having an inclination parallel to the lower half lateral face portion of the driving projection.

Abstract: An elastic crawler traveling apparatus having an elastic crawler in a shape of an endless belt, a sprocket for a crawler belt arranged to be brought into contact with an inner face of the elastic crawler, a driven wheel, and a rolling wheel, the elastic crawler including a belt main body, a plurality of projections formed to project at intervals along a peripheral direction on an inner face of the belt main body, and a tension member embedded at an inner portion of the belt main body for restricting elongation of the belt main body, in which the sprocket has a contact portion to contact the belt main body and a contact width of the contact portion in a belt width direction of the elastic crawler is wider than a root width of the projection in the belt width direction.

Abstract: A spur wheel for the chain drive assembly of a tracked vehicle on which the guide elements of a chain roll during the operation of the chain drive assembly is provided. Certain parts of the spur teeth which come in contact with the rolling area of the guide elements are designed as removable, replaceable parts.

Abstract: This invention relates to the guide lugs of reinforced elastomeric endless traction bands, which are used on heavy vehicles like defence vehicles. More specifically, the invention relates to guide lugs which are partly nested into each other around the curved portion of the traction band in order to minimize de-tracking occurrences.

Abstract: This invention relates to an endless traction band and its plurality of wheels that are used to propel band-laying vehicles [i.e., vehicles which use endless traction bands rather than tires to contact the terrain over which they are driven, e.g., snowmobiles, tractors, tanks, bulldozers, etc.] and, more particularly, to an improved supporting disk for use with the traction band. Each supporting disk comprises a plurality of laterally extending arms adapted to cooperate with the traction band's inner surface when circumferential misalignment occurs.

Abstract: A wheel for belted track vehicles includes a hub with an upright central disc. A series of individually cast and machined segments are mounted to the disc in side-by-side relation about the periphery of both sides of the disc. Each segment takes the shape of a truncated sector having a general “L” shape as viewed from an end, with a back or base engaging a side of the disc, and belt support elements extending laterally of the disc for engaging and supporting the track.

Abstract: An elastic crawler traveling apparatus having an elastic crawler in a shape of an endless belt, a sprocket for a crawler belt arranged to be brought into contact with an inner face of the elastic crawler, a driven wheel, and a rolling wheel, the elastic crawler including a belt main body, a plurality of projections formed to project at intervals along a peripheral direction on an inner face of the belt main body, and a tension member embedded at an inner portion of the belt main body for restricting elongation of the belt main body, in which the sprocket has a contact portion to contact the belt main body and a contact width of the contact portion in a belt width direction of the elastic crawler is wider than a root width of the projection in the belt width direction.

Abstract: A travel driving apparatus for a track-type earthmoving machine is provided which can reduce abrasion wear of a sprocket and a bushing and which enables easy replacement of worn members. A contact member is detachably mounted to an opposing surface of a track shoe to a sprocket, and a tooth top portion of the sprocket is brought into contact with the contact member, thereby securing a gap between a bushing of a track chain and a tooth bottom portion of the sprocket. The tooth top portion of the sprocket and a surface portion of the contact member have surface portions which are brought into contact with each other at a time when the sprocket rotates.

Abstract: An elastic crawler traveling apparatus having an elastic crawler in a shape of an endless belt, a sprocket for a crawler belt arranged to be brought into contact with an inner face of the elastic crawler, a driven wheel, and a rolling wheel, the elastic crawler including a belt main body, a plurality of projections formed to project at intervals along a peripheral direction on an inner face of the belt main body, and a tension member embedded at an inner portion of the belt main body for restricting elongation of the belt main body, in which the sprocket has a contact portion to contact the belt main body and a contact width of the contact portion in a belt width direction of the elastic crawler is wider than a root width of the projection in the belt width direction.

Abstract: A crawler undercarriage mechanism includes a plurality of running rollers, and at least one drive sprocket wheel which is provided with chain teeth, and has a running tread and wheel flanges on both sides. An endless chain with individual chain links which are connected releasably to one another by bolts and a plurality of interengaging outer and inner link plates is driven by the sprocket wheel. Each chain link has two guide webs which have a bearing surface, which interacts with the running treads, and a guide surface, which interacts with respective ones of the wheel flanges. The web guides have a cam-like element which connects the two webs and meshes with the chain teeth of the drive sprocket wheel. The drive sprocket wheel has an involute toothing arrangement which meshes with a rectilinear flank of the cam-like element, and top side of the respective guide web has a concavely curved bearing surface, which interacts with the convexly curved running-tread surface of the drive sprocket wheel.

Abstract: A head sprocket assembly and sprocketless tail roller assembly for a pontoon track drive system wherein the sprocket assembly and tail roller is fitted with a plurality of support rings for straightening the track's elongated cleats attached to a plurality of chains passing lengthwise around the pontoons.

Abstract: An idler for supporting the forward end of an endless track of a track-type tractor has an endless chain resiliently supported on an outer flange of the idler hub. An outer surface of the chain provides a substantially continuous bearing surface for supporting the endless track on the idler.

Abstract: A rubber crawler has a core of generally parallelepiped blocks (5) each having two longitudinally spaced through holes (9) in the lower surface region and bars (4) inserted in the through holes (9), the generally parallelepiped blocks (5) being arranged in two series, with the blocks of one of the series laterally overlapping the blocks of the other series, and with sprocket engaging holes (2) disposed therebetween, and the bars (4) being inserted in alternately corresponding through holes (9) in adjacent generally parallelepiped blocks (5), the bars (4) being connected within the generally parallelepiped blocks (5), the bars (4) being connected within the generally parallelepiped blocks (5) and embedded in the rubber crawler.

Abstract: A drive wheel is provided for mounting on a rotatable axle of a vehicle for driving a continuous flexible track. The flexible track includes an inner surface having a plurality of lugs and terminating at terminal surfaces. The drive wheel includes a central hub mountable on the axle of the vehicle for rotational movement therewith. First and second side-surfaces extend radially from the central hub and an outer rim interconnects the radial outer edges of the side-surfaces. It is intended that the terminal surfaces of the lugs engage the outer rim of the drive wheel such that the lugs are supported when the flexible track is driven by the drive wheel.

Abstract: A drive wheel engaged with flexible track of track apparatus mountable on a vehicle axle, the drive wheel including a peripheral portion which, between radially-extending drive members, has outwardly-facing lug-engagement surfaces in position for engagement with the distal surfaces of the track lugs, to extend the useful life of flexible track. Preferred embodiments have spaces facilitating removal of debris. Certain preferred lug-engaging surfaces are provided by peripherally-spaced cross-members. The drive wheel is preferably free of side structure, allowing track lugs to adjust precise positions of engagement with lug-engagement surfaces.

Abstract: An arrangement for supporting a track chain having a track link, a first bushing mechanically coupled to the track link, and a second bushing mechanically coupled to the track link. The first bushing has a first center point C1 defined thereon. The second bushing has a second center point C2 defined thereon. The first center point C1 is spaced apart from the second center point C2 by a distance D1. The arrangement includes an idler wheel having a circumferentially extending surface defined thereon. The circumferentially extending surface has a first notch and a second notch defined therein. The first notch has a first wall portion. The first wall portion has a first point P1 defined thereon at a first location. The second notch has a second wall portion. The second wall portion has a second point P2 defined thereon at a second location which corresponds to the first location. The point P1 is spaced apart from the point P2 by a distance D2.

Abstract: A guide for a multi-link endless chain of a track-type undercarriage, especially for cranes, has an undercarriage support, at least one drive sprocket wheel provided with chain teeth, possibly an idler, and several track rollers. Each chain link of the endless chain has two guide webs which are symmetric to the center, spaced a certain distance apart, and extend in the travel direction. The webs have engaging surfaces which ride on opposed circumferential flanges on the drive sprocket wheel. A cog connects the two webs below the engaging surfaces and meshes with the chain teeth of the drive sprocket wheel. The guide has two parallel rails oriented in the travel direction of the endless chain, the inside surfaces of the rails coming to rest against the outside surfaces of the associated guide webs when the guide function is occurring.

Abstract: A drive sprocket for an endless chain on a track-type undercarriage includes a toothed wheel having a plurality of circumferential teeth extending from a root circle. A pair of mounting rings fixed to opposite axial sides of the wheel support a respective pair of rotating rings by means of bearings, each rotating ring forming a tread having a diameter which is small than the diameter of the root circle. The endless chain has a plurality of links connected end-to-end, each link having a pair of spaced apart guide webs extending in the direction of travel and connected by a cog which engages between two adjacent teeth on the toothed wheel, each guide web being profiled to ride on one of the treads.