US3601212A - Cushioned track - Google Patents

Cushioned track Download PDF

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US3601212A
US3601212A US884903A US3601212DA US3601212A US 3601212 A US3601212 A US 3601212A US 884903 A US884903 A US 884903A US 3601212D A US3601212D A US 3601212DA US 3601212 A US3601212 A US 3601212A
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portions
shoes
cushioned
central axis
spacer means
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Robert A Peterson
Norman E Risk
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Caterpillar Inc
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Caterpillar Tractor Co
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Assigned to CATERPILLAR INC., A CORP. OF DE. reassignment CATERPILLAR INC., A CORP. OF DE. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: CATERPILLAR TRACTOR CO., A CORP. OF CALIF.
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D55/00—Endless track vehicles
    • B62D55/08—Endless track units; Parts thereof
    • B62D55/14—Arrangement, location, or adaptation of rollers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C27/00—Non-skid devices temporarily attachable to resilient tyres or resiliently-tyred wheels
    • B60C27/20—Non-skid devices temporarily attachable to resilient tyres or resiliently-tyred wheels having ground-engaging plate-like elements

Definitions

  • SHEET 08 DF 13 INVENTORS ROBE/P7 A. PETERSON NORMAN E. R/sK I qt. M 27%0/ ATT C D RNE s PATENTEUAUBZMBH 3.601.212
  • rubber tired tractors are preferred over crawler tractors due to their increased speed capabilities.
  • the rubber tired tractor exhibits a number of deficiencies when compared to the crawler-type tractor such as: lower tractive efficiency; poorer flotation characteristics; and less stability.
  • conventional rubber tires are highly prone to periodic repair or replacement due to their propensity to to wear and damage.
  • standard rubber tires now comprise a substantial fraction, usually from one-tenth to one-fourth at list prices, of the purchase price of a rubber tired machine.
  • Such tires tend to wear out or damage more rapidly than the remaining components of the machine and are normally repaired or replaced a number of times during the machine's life. Repair and replacement costs are greatly affected by the type of surface over which the tire runs as well as the extent of care and maintenance afforded thereto.”
  • Tire wear largely depends upon the 'abrasiveness or sharpness of the tire-engaging surface. For example, sharp gravel and crushed or blasted rock greatly accelerate tread wear. Since wet rubber normally tends to cut more easily .than dry rubber, tire damage is further increased when the tire operates over wet ground. Also, some operators are inclined to run a machine at unduly high speeds to further increase the rate of tire wear. I
  • a conventional rubber tire is induced to roll-off its rim when the vehicle is cornered at high speeds or is tilted laterally during side hill earthmoving operations, for example.
  • roll-off and/or tilting becomes too severe, the vehicle will tip over to thus subject both the machine and its operator to serious damage or injury. Therefore, under such operating conditions machine stability can only be assured by operating the machine at acceptably low-comering speeds and inclinations to ground level.
  • thecushioned track of this invention virtually constitutes a complete departure from the prior art and is a particular contribution to the earthworking and earthmoving industries.
  • cushioned track per se exhibits some incidental similarities to both the above, briefly discussed conventional endless track and'rubber tires, it will be seen that this invention when employed on a vehicle exhibits numerous desiderata and features heretofore unrealized by conventional machinery.
  • a vehicle employing the cushioned tracks of this invention thereon affords the vehicle numerous desirable dynamic characteristics relating to vehicle ride, stability and handling.
  • an object of this invention is to overcome the above, briefly described problems by providing'a cushioned track for ground engaging vehicles capable, of yielding high monetary and power utilization savings by combining the high speed, steering and load carrying capabilities of a conventional rubber tired machine with the high torque earthworking capabilities of a conventional track-type machine.
  • the multipurposeand highly durable cushioned track is particularly adapted for use with multiaxled, heavy duty earthworking and/or transport machines to greatly improve the vehicles dynamic characteristics relating to vehicle ride, stability and handling.
  • a cushioned track constructed pursuant to the teachings of this invention will exhibit excellent and closely controlled suspension characteristics, including stability, and a high degree of structural integrity heretofore unrealized by conventional support mechanisms.
  • the cushioned track of this invention is adapted to be rotated about a central axis thereof and comprises an annular resilient spacer means having an annular, endless track assembly mounted therearound.
  • the track assembly comprises a plurality of closely coupled ground-engaging shoes connected together by laterally spaced link assemblies, positioned outboard of the resilient spacer means, toform a unitized construction.
  • the spacer means outer periphery is normally circular about its central axis and in its relaxed state and is compressed by inner surface portions of the shoes to form a substantially continuous surface contact therebetween.
  • Restraining means are positioned on opposite sides of the spacer means to prevent lateral movement thereof relative to the shoes.
  • FIG. 1 is a perspective view of an articulated loader mounted on four cushioned tracks of this invention
  • FIG. 2 is a side elevational view of an articulated bulldozer mounted on four cushioned tracks of this invention
  • FIG. 3 is a side elevational view of a tractor-scraper mounted on four cushioned tracks of this invention
  • FIG. 4 is a side elevational view of a tractor having a drawn implement attached thereto;
  • FIG. 5 is a side elevational view of a tractor having a ripper attached thereto;
  • FIG. 6 is a side elevational view of a cushioned track embodiment of this invention comprising a resilient spacer and track assembly, shown as it would appear with a load L imposed thereon;
  • FIG. 7 is a cross-sectional view taken on line VIlVll in FIG. 6;
  • FIG. 8 is an enlarged, side elevational view of a portion of an endless track assembly employed in the cushioned track of FIGS. 6 and 7;
  • FIG. 9 is a cross-sectional view taken on line IXIX in FIG.
  • FIG. 10 is an exploded, isometric view of a portion of a link assembly employed in the FIG. 8 track assembly;
  • FIGS. 11-16 illustrate resilient spacer modifications which may be employed in the cushioned track
  • FIGS. 17 and 18 illustrate track assembly modifications which may be employed in the cushioned track
  • FIGS. 19-21 illustrate link assembly modifications which may be employed in the track assembly
  • FIGS. 22-24 illustrate alternative cushioned track embodiments
  • FIGS. 25-29 illustrate various grouser arrangements which may be employed on ground-engaging shoes employed in the track assembly
  • FIG. schematically compares a cushioned track embodiment of this invention to a convention pneumatic tire
  • FIG. 31 schematically illustrates design parameters relating to the cushioned track of this invention.
  • FIG. 1 illustrates an articulated, self-propelled loader of the type manufactured by Caterpillar Tractor Co. and known as its 950 Loader.”
  • the loader comprises a tractor having first and second sections 51 and 52, respectively, articulated together for relative pivotal movement in a conventional manner about a vertically disposed axis positioned between the two sections.
  • This invention comprises the substitution of two pairs of vertically disposed cushioned tracks 53 in lieu of conventional pneumatic rubber tires.
  • Each pair of the cushioned tracks normally has a horizontally disposed common axis of rotation when positioned on level ground.
  • a first pair of the cushioned tracks mounted on section 51 may be steered simultaneously relative to the second pair of cushioned tracks mounted on section 52.
  • Standard integrated loader bucket, lift arms and tilt linkage means 54 are pivotally mounted on the forward end of frame section 51 for selective actuation by the operator.
  • the cushioned track of this invention is particularly useful with such articulated, multiaxled machines to render them capable of exhibiting the above-described desiderata.
  • the cushioned track may also be utilized with many other types of ground-engaging vehicles or machines, such as the 834 Bulldozer and 657 Scraper illustrated in FIGS. 2 and 3, respectively.
  • the bulldozer comprises a conventional bulldozer attachment 55 mounted on the front end of the tractor in a conventional manner.
  • the scraper essentially comprises tractor and bowl sections 56 and 57, respectively, connected together in a conventional manner for simultaneous movement.
  • FIG. 4 illustrates a drawbar-pull application of this invention wherein a ground-engaging implement means 58, shown in the form of an ofiset disc-type harrow, is operatively connected to the rear end of the FIG. 2 tractor.
  • FIG. 5 illustrates the type of articulated tractor shown in FIGS. 2 and 4, but further comprising a selectively actuated ripper means 59, pivotally mounted on the rear end thereof.
  • a conventional hydraulic cylinder 60 may be utilized to selectively pivot and move the ripping means at least partially below the cushioned tracks and ground level for ripping or scarification purposes.
  • each cushioned track may be suspended on its own, individually suspended axle or, alternatively, each pair of laterally spaced cushioned tracks may be constructed and arranged to continuously have the same central axis of Rotation X (FIG. 6).
  • FIGS. 6-10 illustrate one cushioned track embodiment, subjected to a vertically downwardly imposed load L by the weight of the machine.
  • the cushioned track comprises an annular resilient spacer means 61 having a substantially annular, preferably polygonal-shaped endless track assembly 62 mounted completely therearound.
  • the spacer means comprises a resilient member 63, shown in the form of an air-inflated rubber tire or air bag mounted on a conventional rim means 64.
  • the rim may be suitably connected to the vehicle s drive axle or drive output (not shown) to be driven and rotated about the central axis X thereof by an internal combustion engine 65 (FIG. 1) in a conventional manner.
  • the spacer means comprises opposed side portions 66 and 67 (FIG. 7) connected together by a substantially annular peripheral portion 68 having a width extending laterally relative to the side portions and in the direction of axis X.
  • the FIG. 6 pneumatic tire spacer means embodiment may be of standard construction comprising suitably integrated interliner, body plies and tread plies. For reasons hereinafter more fully explained, the tire embodiment preferably shows an absence of any appreciable amount of ground-engaging treads on outer surface portions 69 of periphery 68 thereof.
  • the resilient member may be either molded to have smooth and uninterrupted outer surface portions 69 or conventional treads of a particular resilient member may be at least substantially ground-off by a suitable burnishing apparatus, for example.
  • Outer surface portions 69 could be slightly roughened or serrated in certain applications to increase the coefiicient of friction thereat.
  • FIG. 11 illustrates one preferred resilient member embodiment 63a wherein outer surface portions 69a, as well as the intersecting outer surfaces of side portions 66a and 67a, are preferably molded or otherwise formed to be completely smooth and uninterrupted.
  • outer surface portions 69a may be normally convex with respect to the central rotational axis X (FIG. 6) in their freely relaxed condition.
  • FIGS. 6 and 11 resilient member embodiments of the spacer means are each adapted to define a closed, annular chamber 70 (FIG. 7) with the employed rim means 64.
  • a conventional valve stem (FIG. 6) or other suitable inflation means may be utilized to pressurize such chamber with a suitable gas, such as air or nitrogen, preferably to a pressure level selected from the range offrom l5 p.s.i. to I00 p.s.i. The selected pressure level will depend on the particular cushioned track application under consideration which will dictate the desired size, strength and related design parameters for the resilient member.
  • the respective peripheral portions of the spacer means must be constructed to afford the strength, support and drive desiderata hereinafter more fully described.
  • the connected side portions thereof must exhibit sufficient rigidity and stiffness to transmit driving torque to such peripheral portion without collapsing or otherwise unduly distorting the resilient member during operation and particularly when it is subjected to heavy loads.
  • chamber 70 could be at least partially filled with a liquid (hydroflated) to aid in further increasing the traction and drawbar pull capabilities of a particular machine.
  • chamber 70 could be filled with a homogeneous, resilient filling agent or plastic foam 70b (FIG. 13), such as certain polyurethane foams, polyvinyl chlorides or polyethylenes.
  • a solid resilient member 63c (FIG. 14) could also be used and mounted on a single-piece rim means 640 so long as material 700 for the resilient member is constructed and arranged to exhibit the required resiliency, durability and related design desiderata.
  • the endless track assembly means is mounted on and completely around the spacer means to form a boxed-in" and unitized construction therewith.
  • the track assembly comprises a plurality of closely coupled ground-engaging shoes 71 disposed at least substantially parallel and aligned with horizontally disposed central axis X of the cushioned track.
  • the shoes are constructed to have widths defining outboard portions 72 and 73 extending laterally across and beyond the respective side portions of the spacer means (FIG. 7).
  • Inner surface portions 74 of each of the shoes are substantially smooth and uninterrupted and are maintained solely in intimate frictional contact with outer surface portions 69 of the spacer means.
  • the track shoes are preferably suitably alloyed with heavy cross sections to resist bending and deep hardened to exhibit long wear.
  • outer surface portions 69a thereof are normally continuous and circular about the central axis X of the spacermeans in their freely relaxed condition (FIG. 11).
  • inner surface portions 74 of shoes 71 When compressed by inner surface portions 74 of shoes 71 at least a substantial portion of outer surface portions 69a assume a substantially continuous polygonal-shaped surface contact therewith (FIGS. 6 and 12).
  • the outer peripheral portion of the spacer means is preferably compressed by the shoes to have its outside diameter D (FIG. 31) assume less than 99 percent of its normal, freely relaxed and inflated outside diameter (FIG. 11), in most cushioned track applications.
  • outer surface portions of the FIGS. ll, 13, 14 and 16 resilient member embodiments are normally substantially flat and parallel to central axis X of the cushioned track when in their freely relaxed condition.
  • outer surface portions could be molded to normally assume an arcuate shape (convex or concave) with respect to such central axis in their freely relaxed condition.
  • annular outer surface portions 69d of the FIG. 15 spacer means embodiment are concave relative to central axis X when chamber 70d of resilient member 63d is deflated. When the chamber of such spacer means is inflated and surface portions 69d are compressed by the constraining track assembly, they will assume the illustrated dotted line, flat position 69d, parallel to central axis X. Such arrangement will further aid in counteracting any tendency for the shoes to bend to thus further increase the structural integrity of the unitized spacer means.
  • FIG. 16 illustrates an excellent type of resilient member embodiment 63c for purposes of this invention comprising a closed, completely sealed air inflated chamber 702.
  • These types of resilient members are fully disclosed in US. Pat. application Ser. No. 835,499 filed on June 23, 1969 by Charles E. Grawey for Belted Oval Pneumatic Tube-Tire. Such application is assigned to the assignee of this application.
  • the oval-shaped tube tire disclosed therein comprises radially disposed reinforcement windings about the torus thereof to restrict growth in the direction of the torus major axis and rotational axis X (FIG. 6).
  • the tube tire thus primarily expands radially outwardly in the direction of its minor axis and is capable of containing a widely varied air pressure level in chamber 70e thereof.
  • FIG. 14 illustrates a rim means 64c which is formed as a one-piece casting or stamping, for example, to mount the resilient member thereon.
  • FIG. 16 illustrates a rim means embodiment 64c comprising substantially identical L-shaped parts 75:: having first leg portions extending radially inwardly towards central axis X of the spacer means and attached together by conventional rivet means 76e or the like. Leg portions 75e supporting the resilient member thereon, extend away from each other in the direction of the central axis of the cushioned track.
  • each metallic shoe 71 may comprise a substantially flat plate having a substantially uniform thickness throughout. It should be further noted that the plate is parallel to central axis X to continuously maintain inner surface portions 74 thereof also parallel and aligned with such axis. Although inner surface portions 74 are preferably flat, it should be noted that in certain applications such smooth and uninterrupted surface portions could be arcuately shaped in the direction of their circumferential length about central axis X and/or in a lateral direction relative to such circumferential length.
  • such surface portions could be formed slightly concave or convex in the direction of axis X depending on the particular match-up with outer surface portions 69 of the spacer means.
  • inner surface portions 74 of the shoes are preferably metallic, they may be coated with a resilient rubberlike plastic or rubber-based material, for example. Such material could be in the form of an insert which is vulcanized or otherwise secured to the shoes. Likewise a metallic insert could be secured to inner surface portions 74 and have an arcuate or flat shape formed thereon;
  • the track assembly further comprises an annular link assembly 80 positioned adjacent to each of the side portions 66 and 67 of the spacer means to closely couple the shoes together.
  • the shoes may be attached to the link assemblies by releasable bolt means 81, for example, to facilitate change of one or more of the shoes should such change become necessary.
  • Each link assembly preferably extends radially inwardly a substantial distance toward central axis X from inner surface portions 74 of the shoes.
  • each of the link assemblies abut outboard portions 82 and 83 of respective side portions 66 and 67 to provide restraining means for preventing lateral movement of the resilient member in the direction of axis X and relative to the shoes.
  • annular grooves it may prove desirable to form annular grooves (not shown) at outboard portions 82 and 83 to move the link assemblies toward each other and at least partially within the confines of side portions 66 and 67,
  • vertical damping movements of the cushioned track in FIG. 6 may cause five shoes, for example, to flatten out at footprint F on the ground.
  • a portion of the above-mentioned radially extending portions of the side portions may tend to fold over" and at least partially abut over the link assemblies in FIG. 7.
  • each link assembly comprises a plurality of laterally spaced first and second pairs of links 85-86 and 87-88.
  • the links are preferably heavily strutted to assure uniform loading, minimize stress concentrations and to evenly distribute wear.
  • Each link of each pair of links overlaps an adjacent link of an adjacent pair of links so that inner overlapped first end portions 89 and 90 of the first pair of links 85-86, for example,
  • each link assembly presents substantially smooth and circumferentially continuous inboard surface portions or restraining means abutting outboard surface portions 82 and 83 of the spacer means (FIG. 7
  • the pivot means for pivotally connecting the first end portions of the first pair of links to the second end portions of the second pair of links may comprise a pin 93 extending through the first pair of links and press-fitted into or otherwise suitably connected to the second end portions 91-92 of the second pair of links.
  • the second pair of links are thus attached together for simultaneous rotation about the longitudinal axis of the pin.
  • a bearing bushing 94 is mounted for limited rotational movement relative to the pin by its press-fit connection to first end portions 89-90 of the first pair of links.
  • the bushings may be cold-forged and formed with slightly tapered ends internally thereof to aid in resisting undue shocks and stresses.
  • the pins are preferably induction hardened to exhibit high wear-resistant and smoothly finished bearing surfaces over a tough core.
  • the relative hardnesses of the pins and bushings are preferably compatible to minimize wear.
  • each pin 93 is preferably positioned substantially parallel relative to central axis X of the cushioned track and further positioned substantially intermediate a respective pair of adjacent shoes connected together thereby.
  • Such an arrangement facilitates a close coupling of the shoes together and also permits them to move into contact with the ground at footprint F in a substantially smooth, uninterrupted and continuous manner.
  • close coupling aids in forming the substantially continuous and uninterrupted polygonal shape of surface portions 74 which completely surround the spacer means.
  • first and second lugs or stops 95 and 96 are formed integrally with each shoe, at respective ends thereof.
  • the lugs function in conjunction with the abovedescribed intermediate position of pin 93 to completely mask each other during rotation of the cushioned track.
  • lug 95 of one shoe will completely cover second lug 96 of a leading shoe to protect the spacer means against damage and dirt infiltration during all phases of machine operation.
  • conventional sealing means shown in the form of two pairs of back-to-back cone-shaped metal discs or Belleville-type washers 97 of the type disclosed in U.S. Pat. No. 3,050,346, for example, may be utilized in the link assembly.
  • a pair of the washers are mounted on each end of the pin to be compressed between the end of the bushing and one of the links 87 and 88 for sealing purposes.
  • the links have suitable counterbores formed therein (FIG. 9) to accommodate reception of the washers.
  • FIG. 17 illustrates a modified track assembly wherein link assemblies 80a each comprise annular surface portions 98 formed on inboard surface portions of links 85a-88a to diverge relative to each other radially inwardly toward the central axis of the cushioned track.
  • FIG. 18 discloses another track assembly embodiment wherein the link assemblies are positioned laterally and out of abutting contact with respect to outboard surface portions 82 and 83 of the sidewall portions of the resilient member.
  • two metallic bands or lugs 99 are secured to inner surface portions 74 of each track shoe to abut the outboard surface portions of the resilient member to provide the restraining means preventing lateral movement thereof.
  • FIGS. 19-21 illustrate additional link assembly embodiments.
  • identical links 85b each comprises blade end 89b mounted in a fork end 91b of an adjacent link by a track pin cartridge 9311.
  • Such cartridge is fully disclosed in U.S. Pat. No. 3,463,560, assigned to the assignee of this invention.
  • FIG. 20 illustrates a link assembly embodiment and c wherein a resilient and preferably slightly compressed rubber bushing or sleeve 100 is positioned between each pair of pins and bushings 93c and 940.
  • the resilient sleeve may be vulcanized or otherwise suitably secured to the pin and bushing to closely control rotational movement therebetween to improve damping and speed capabilities of the cushioned track for certain applications.
  • FIG. 20A illustrates a link assembly embodiment 80d wherein a rubber sleeve 100a is vulcanized between metallic bushings 94d and 94d to aid in relieving high-pinch" loads. Rotary frictional contact is occasioned between inner bushing 94d and pin 93.
  • the FIG. 21 link assembly embodiment c comprises a single set of links d comprising a bushing 94c pressed into the bushing end 89d of the link. A pin 93d is inserted through the bushing and press-fitted or otherwise secured to end 91d of the connected link. It should be understood that the FIGS. 8-10 double-link assembly embodiment would be preferred over the FIG. 21 single-link embodiment for most cushioned track applications due to its increased antisnaking, rigidity and damping capabilities, for example.
  • FIGS. 22-24 illustrate modifications to the cushioned track wherein the widths of shoes 71a are elongated so that they extend a substantially greater distance beyond one side portion 67 of the resilient member than the opposite side portion 66.
  • a third identical link assembly 80 is attached to the shoe outboard of the other link assemblies and dual spacer means are mounted for simultaneous rotation by a common drive axle (not shown).
  • the second spacer means has been removed to permit the cushioned track to run in the manner illustrated.
  • the third link assembly is eliminated to provide uneven overhangs 0 (FIG. 31) to provide increased flotation capabilities on soft ground, for example.
  • FIGS. 25-29 illustrate a number of grouser arrangements which exhibit various desirable traction characteristics.
  • the FIGS. 6 and 25 grouser arrangement comprises three identical grousers 101 secured to the outer surface portions of the shoe and substantially equally spaced thereon.
  • the radial height of the grousers are equal and extend laterally in the direction of the central axis of the cushioned track and at least substantially fully across the width of the shoe.
  • FIG. 26 grouser arrangement is substantially similar to the one shown in FIGS. 25, except that leading grouser 102 has a height greater than the height of the other two grousers 101. Such a grouser 102 would be preferred in certain applications to increase tractive capabilities and to strengthen the shoes when operating over certain soil conditions.
  • FIG. 27 illustrates a grouser arrangement similar to the one illustrated in FIG. 26, except that grousers 101 have been eliminated.
  • the FIG. 28 grouser arrangement is similar to the FIG. 27 grouser arrangement, except that an additional cross grouser 103 is secured to the shoe to extend perpendicularly relative to grouser 102.
  • FIG. 29 illustrates a further grouser arrangement wherein a V-shaped chevron" grouser 104 is secured to the track shoe.
  • the FIG. 6 track assembly may be assembled by at least partially deflating spacer means 61 and then wrapping uncoupled track assembly 62 therearound.
  • a suitably sized master pin 93 may be employed in each of the link assemblies to facilitate such uncoupling.
  • a breakable link of the type disclosed in U.S. Pat. No. 3,427,079 could be utilized for coupling purposes.
  • the loose ends of the track assembly may be drawn together by a suitable cinch or the like to align the mating master pin" retaining bores of such ends.
  • chamber 70 of the spacer means is pressurized with air to a predetermined level. The magnitude of such level will largely determine the degree to which the spacer means is 'compressed by the track assembly to provide the above-discussed surface contact and drive means desiderata between surfaces 69 and 74 (FIG. 7).
  • circumferential lengths of all sides of the polygonal surface contacts are preferably equal, it should be understood that in certain applications that one or more or such sides may be formed to a length difierent that the remaining sides.
  • the alternate circumferential lengths of each adjacent pair of coupled shoes could be ten inches and20 inches, respectively.
  • surfaces 74 could be preformed to be arcuate rather than flat to thus define a substantially circular circumferential length about axis X.
  • the method for imparting drive to the above-described cushioned track comprises the steps of: Completely surrounding the periphery of vertically disposed spacer means 61, exhibiting a substantially equal air pressure level in chamber 70 (FIGS. 6 and 7), with endless track assembly 62; compressing and deforming the periphery of the spacer means with shoes 71 against the counteracting radial pressure occasioned by the air pressure in chamber 70, so that it normally assumes a substantially circumferentially continuous surface contact with inner surface portions 74 of the shoes about central axis X (FIG.
  • the compressing and deforming steps comprise. the steps of compressing and deforming the periphery of the spacer means so that: The circumferential lengths of inner surface portions 74 of each of the shoes are substantially equal; the polygonal-shaped surface contact area is substantially parallel to central axis of rotation X; and the circumferential length of each of the inner surface portions of the shoes normally defines (with load L not imposed on the cushioned track) the base of an isosceles triangle having its apex at the central axis and having its sides or radii defining an included angle a (FIG. 6) therebetween selected from the range of from 6 to 30.
  • FIG. 31 schematically illustrates design parameters relating to the cushioned track of this invention and in particular to the tested FIGS. 6-10 embodiment.
  • the dimensional parameters illustrated have the following meanings:
  • C Chord or Maximum Width of Resilient Member 63
  • S Sectional Height of Resilient Member 63 Lateral distance B is preferably equal to or greater than 0.20 to assure a sufficiently large surface contact between surfaces 69 and 74 for driving purposes and for assuring adequate load carrying capabilities. The upper limit of such relationship of B to D will depend upon the particular cushioned track application in question.
  • Overhang O is preferably equal to or greater than 0.lS to fully protect the sectional height of resilient member 63.
  • the upper limit of S will largely depend upon the accommodating space limitations of a particular machine on which the cushioned track is employed.
  • Lateral width E defining the surface contact between surface 69 and 74, is preferably selected from the range of from 05C to 1,0C. Should such surface contact fall below 0.5 C, the desired amount of dry" frictional contact will be lost to induce slippage and dirt infiltration, an unduly high amount of rubbing contact between link assemblies and side portions 66 and 67 will be induced and uneven stress distributions will be promoted in shoes 71. Such problems, which may arise depending on the particular cushioned track application, will tend to diminish when E moves toward 1.0C.
  • the cushioned track and method teachings of this invention afford a number of observed features and benefits, particularly useful for earthworking machines such as scrapers, motor graders, wheel loaders, bulldozers and other types of machines utilizing a work tool and/or utilized for transport purposes. Additional applications may include military hauling and combat units, log skidders and haulers and the like. As suggested in the objects of this applications many such machines are now capable of performing heavy duty and high-speed (e.g., 30 mph.) operations at a working efficiency heretofore unrealized by conventional machines and greatly improve the dynamic characteristics thereof.
  • the dynamic characteristics i.e., handling, stability and ride of a vehicle mounted on cushioned tracks of this invention such as the 950 Loader illustrated in FIG. 1, are greatly improved over the dynamic characteristics of conventional earthmoving vehicles.
  • Cornering stiffness is an important design consideration which affects vehicle handling or directional control and may be defined as the negative of the derivative of the cornering force with respect to the slip angle of the cushioned track.
  • the slip angle is the angle between the direction of cushioned track heading and the direction of cushioned track travel.
  • the four cushioned track vehicle can be steered in automotive fashion.
  • a conventional two-track type tractor is normally steered by disengaging one track and by powering the other track to effect a turn. If the tractor is under high load, the powered track may spin out resulting in an inefficient turning cycle.
  • the dynamic stability of the cushioned track vehicle is also markedly improved over that of conventional vehicles.
  • the dynamic stability characteristics of the vehicle can be described by several basic modes of vibration. Such modes will largely depend upon the design characteristics of the cushioned track, vehicle design parameters and the vehicles operational configuration, i.e., bucket-up, bucket-down, bucket loaded or bucket empty.
  • the most predominant mode sensed as stability is the mostly lateral mode of vehicle vibration occurring when the lift arms are fully raised which is excited by lateral forces on the vehicle and ground irregularities.
  • This mode of vibration is generally characterized by vehicle motion which oscillates about a nodal-axis near ground level.
  • the frequency of the mode for one conventional, fully vehicle rubber-tired loader approximates 0.5 c.p.s., which is sufficiently low to afford the operator an insecure feeling during certain phases of loader operation.
  • the cushioned track vehicle assures a substantial relative increase in the vertical spring rate of the resilient members, a larger footprint F (causing the effective spring rate of the soil to increase), and a larger effective tread width of the vehicle.
  • a mostly yaw mode of vibration occurs when the loader bucket is in the carry position, with the cushioned tracks either braked or free to roll fore-aft.
  • This mode influences the operator's sense of vehicle stability and is excited most often when steering corrections are made.
  • This mode of vibrations normally occurs at about 1.0 c.p.s. for a conventional rubber-tired loader.
  • the previously mentioned design parameters exhibited by the cushioned track affect this mode advantageously.
  • a high lateral spring rate and static aligning spring rate are exhibited which tend to increase the frequency of the mode, thus giving the operator a feeling of improved stability.
  • fore-aft (or longitudinal) stability can be characterized by the mostly fore-aft mode of vehicle vibration, which generally occurs when the vehicles brakes are applied. This mode is most easily excited when the bucket is raised or dropped abruptly.
  • the fore-aft dynamic stability is improved by increasing the mostly fore-aft mode frequency which is accomplished by increasing the vertical spring rate and effective footprint area of the cushioned track.
  • the dynamic ride characteristics of a conventional rubbertired vehicle are primarily influenced by mostly pitch and mostly bounce modes of vibration. in general a smoother ride will be occasioned at the lower frequencies of these modes and visa versa.
  • the cushioned track an increase in such frequencies and a significant increase in damping provide an improved ride for most roading conditions.
  • increased damping afforded by the cushioned track greatly improves all modes of dynamic stability. Increased damping causes the vibrations to decay rapidly with little chance for successive vibration inputs to cause conditions bordering on instability.
  • the cushioned track per se forms a unitized, boxed-in construction which is totally integrated to afford it great stability and structural integrity.
  • the degree to which spacer means 61 conforms to the polygon shape of the track assembly (FIG. 6) is primarily dependent on the amount of radial squeeze imparted to the spacer member by the track assembly and by the spacer means counteracting stiffness.
  • the spacer means would normally require compression so that it will assume at least 99 percent of its normal, relaxed diameter and circumferential surface area.
  • radial ply resilient members for example, such value may be as high as 98 and in relatively soft resilient members as low as 75.
  • Torque transmitted to the spacer means by the machines drive axle and rim means 64 is transferred to the track assembly via side portions 66 and 67 which must exhibit sufficient stiffness to prevent excessive wind-up" and related spacer means distortion.
  • the sectional height of the resilient member may be quite short (e.g. 10 percent) in relation to the outer radius of the spacer means.
  • torque is transmitted to shoes 71 primarily through the surface contact between abutting surfaces 69 and 74.
  • the cushioned track even though capable of speeds in excess of 30 m.p.h., is able at speeds even as low as 2 mph. to transmit at least 75 percent of the machines weight L (FIG. 6) through the spacer means and to the tracks in the form of traction.
  • FIG. 6 cushioned track embodiment inflated from 30 to 60 psi. when tested for typical vehicle applications and under typical operating conditions normally developed approximately 45 percent frictional drive to the shoes at footprint F and approximately 55 percent frictional drive to the shoes around the remaining circumferential length (e.g. 300) of the shoes.
  • the relative percentages of such frictional drives will depend, for example, on soil conditions, the coefficient of friction between the various portions of surface contacts 69-74, inflation pressure, geometric and structural design criteria and related design parameters. The preferred range for each of the above percentages is 50 percent plus or minus 10 percent.
  • Another feature of this invention is the inherent ability of the cushioned track to normally, continuously maintain frictional contact between surfaces 69 and 74 during all phases of machine operation.
  • the abutting surfaces tend to form a static seal to prevent water, dirt and the like from entering between the spacer means and track shoes.
  • the ability of the resilient spacer means to substantially conform to the polygonal configuration of shoes 71 assures such sealing desideratum even though the shape of the track changes due to external forces, such as the weight L of the vehicle and forces occurring as a result of vehicle movement.
  • the construction and arrangement of lugs and 96 and their structural relationship to pin 93 further aid in the sealing and self-cleaning functions.
  • the drive means created between the spacer means and the shoes provides the main (e.g., 75 percent) torque transmitting driving means for a machine.
  • the coefficient of friction between such abutting surface portions may be maintained less than 1.0 by suitably reducing the air pressure in chamber 70, for example, to permit limited relative rotational movement to occur therebetween under extreme conditions of operation to prevent damage to the machine.
  • the air pressure in chamber 70 for example, to permit limited relative rotational movement to occur therebetween under extreme conditions of operation to prevent damage to the machine.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Tires In General (AREA)
  • Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
  • Escalators And Moving Walkways (AREA)
  • Non-Deflectable Wheels, Steering Of Trailers, Or Other Steering (AREA)
US884903A 1969-12-15 1969-12-15 Cushioned track Expired - Lifetime US3601212A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US88490369A 1969-12-15 1969-12-15

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US3601212A true US3601212A (en) 1971-08-24

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US884903A Expired - Lifetime US3601212A (en) 1969-12-15 1969-12-15 Cushioned track

Country Status (9)

Country Link
US (1) US3601212A (es)
BE (1) BE760306A (es)
CA (1) CA919072A (es)
CH (1) CH553683A (es)
DE (1) DE2050972C3 (es)
ES (1) ES385394A1 (es)
FR (1) FR2070851B1 (es)
GB (1) GB1320532A (es)
ZA (1) ZA706450B (es)

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3712687A (en) * 1970-11-20 1973-01-23 Caterpillar Tractor Co Dual pitch track links for adjustment of cushioned tracks
US3717388A (en) * 1970-11-20 1973-02-20 Caterpillar Tractor Co Spacer means for cushioned track
US3717389A (en) * 1970-12-23 1973-02-20 Caterpillar Tractor Co Pitch adjustment means for track assemblies
US3717387A (en) * 1970-11-12 1973-02-20 Caterpillar Tractor Co Cushioned track with cross grousers
US3720448A (en) * 1970-11-20 1973-03-13 Caterpillar Tractor Co Cushioned track with anti-slippage means
US3736032A (en) * 1970-01-28 1973-05-29 Uniroyal Inc Pneumatic drive sprocket for tracked vehicles
DE2608795A1 (de) * 1975-03-03 1976-09-16 Caterpillar Tractor Co Gleiskettenschuh mit greifrippen
US4097085A (en) * 1976-08-10 1978-06-27 Harmon's Northern Mfg., Inc. Tractor
US4257653A (en) * 1979-08-23 1981-03-24 Caterpillar Tractor Co. Track assembly for track-type vehicles with dual link assemblies
WO1983003231A1 (en) * 1982-03-12 1983-09-29 Meisel, Thomas, C., Jr. Endless track coupling apparatus
US4602825A (en) * 1979-08-23 1986-07-29 Caterpillar Tractor Co. Anti-torsion means for track assemblies for track-type vehicles
US5556487A (en) * 1995-01-27 1996-09-17 Soudures Et Chaines Pedno Inc. Track device having wheel widening effect
US20060070775A1 (en) * 2003-06-17 2006-04-06 Science Applications International Corporation Toroidal propulsion and steering system
CN100396534C (zh) * 2006-11-24 2008-06-25 湖南农业大学 履带式多路况自动变形轮
US20080284245A1 (en) * 2007-05-18 2008-11-20 Caterpillar Inc. Machine track system and machine track segment
US20090051218A1 (en) * 2007-08-24 2009-02-26 Crooks Jeffrey J A Traction Enhancement Device
US20100276990A1 (en) * 2009-04-29 2010-11-04 Camoplast Inc. Track assembly for an all-terrain vehicle (atv) or other tracked vehicle
US20140156105A1 (en) * 2012-11-30 2014-06-05 Caterpillar Inc. Conditioning a Performance Metric for an Operator Display
US20140306516A1 (en) * 2013-04-16 2014-10-16 Caterpillar Inc. Vibration-damped track shoe for mobile machine
US9211922B2 (en) 2012-08-17 2015-12-15 Cardinal Gibbons High School Robotic vehicle having traction and mobility-enhanced wheel structures
USD748153S1 (en) 2014-05-22 2016-01-26 Harnischfeger Technologies, Inc. Crawler track shoe
US20160176456A1 (en) * 2014-12-22 2016-06-23 Caterpillar Inc. Reversible Track Link System
US9676431B2 (en) 2013-05-24 2017-06-13 Harnischfeger Technologies, Inc. Crawler track
US9776676B2 (en) 2013-11-12 2017-10-03 Harnischfeger Technologies, Inc. Guide rail for crawler track
US11241908B2 (en) * 2018-05-01 2022-02-08 Nicholas E. Mansfield Flex track

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Publication number Priority date Publication date Assignee Title
JPS53165446U (es) * 1977-05-27 1978-12-25
DE102014113585B4 (de) 2014-09-19 2019-01-17 Technische Universität Dresden Fahrwerk und Fahrzeug

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US2008210A (en) * 1933-08-12 1935-07-16 Otho F Hipkins Traction device
US2046299A (en) * 1934-08-31 1936-06-30 Euclid Road Machinery Company Crawler wheel link
US2431599A (en) * 1943-05-26 1947-11-25 William E Wine Traction device
US2917095A (en) * 1958-01-27 1959-12-15 Camille P Galanot Traction device for a vehicle with tires or the like
US2973995A (en) * 1959-01-08 1961-03-07 Jacob J Weier Traction devices

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GB203411A (en) * 1922-06-09 1923-09-10 Alberto Redenti Improvements in or relating to endless tracks for tractors and other heavy vehicles
US2764207A (en) * 1952-10-27 1956-09-25 Gen Motors Corp Tire track with elastic tire
US2764204A (en) * 1952-12-04 1956-09-25 Gen Motors Corp Tire tracks with tire engaging lugs
US2755146A (en) * 1952-12-31 1956-07-17 Camille P Galanot Traction device
US2821443A (en) * 1956-07-16 1958-01-28 Camille P Galanot Traction device for a vehicle with tires or the like
US3206258A (en) * 1964-03-06 1965-09-14 Pettibone Mulliken Corp Chain link and seal arrangement
US3369622A (en) * 1966-01-24 1968-02-20 Nyal Deveraux Thomas Sr. Center drive vehicle mechanism
US3372959A (en) * 1966-08-05 1968-03-12 Cleal T. Watts Jr. Grouser for tractor
US3439959A (en) * 1967-07-18 1969-04-22 G L Bowen & Co Endless steel track construction

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Publication number Priority date Publication date Assignee Title
US2008210A (en) * 1933-08-12 1935-07-16 Otho F Hipkins Traction device
US2046299A (en) * 1934-08-31 1936-06-30 Euclid Road Machinery Company Crawler wheel link
US2431599A (en) * 1943-05-26 1947-11-25 William E Wine Traction device
US2917095A (en) * 1958-01-27 1959-12-15 Camille P Galanot Traction device for a vehicle with tires or the like
US2973995A (en) * 1959-01-08 1961-03-07 Jacob J Weier Traction devices

Cited By (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3736032A (en) * 1970-01-28 1973-05-29 Uniroyal Inc Pneumatic drive sprocket for tracked vehicles
US3717387A (en) * 1970-11-12 1973-02-20 Caterpillar Tractor Co Cushioned track with cross grousers
US3712687A (en) * 1970-11-20 1973-01-23 Caterpillar Tractor Co Dual pitch track links for adjustment of cushioned tracks
US3717388A (en) * 1970-11-20 1973-02-20 Caterpillar Tractor Co Spacer means for cushioned track
US3720448A (en) * 1970-11-20 1973-03-13 Caterpillar Tractor Co Cushioned track with anti-slippage means
US3717389A (en) * 1970-12-23 1973-02-20 Caterpillar Tractor Co Pitch adjustment means for track assemblies
DE2608795A1 (de) * 1975-03-03 1976-09-16 Caterpillar Tractor Co Gleiskettenschuh mit greifrippen
US4097085A (en) * 1976-08-10 1978-06-27 Harmon's Northern Mfg., Inc. Tractor
US4257653A (en) * 1979-08-23 1981-03-24 Caterpillar Tractor Co. Track assembly for track-type vehicles with dual link assemblies
US4602825A (en) * 1979-08-23 1986-07-29 Caterpillar Tractor Co. Anti-torsion means for track assemblies for track-type vehicles
WO1983003231A1 (en) * 1982-03-12 1983-09-29 Meisel, Thomas, C., Jr. Endless track coupling apparatus
US4530546A (en) * 1982-03-12 1985-07-23 Caterpillar Tractor Co. Endless track coupling apparatus
US5556487A (en) * 1995-01-27 1996-09-17 Soudures Et Chaines Pedno Inc. Track device having wheel widening effect
US7387179B2 (en) 2003-06-17 2008-06-17 Science Applications International Corporation Toroidal propulsion and steering system
US20060170386A1 (en) * 2003-06-17 2006-08-03 Science Applications International Corporation Toroidal propulsion and steering system
US20060261771A1 (en) * 2003-06-17 2006-11-23 Science Applications International Corporation Toroidal propulsion and steering system
US7235046B2 (en) 2003-06-17 2007-06-26 Science Applications International Corporation Toroidal propulsion and steering system
US20060070775A1 (en) * 2003-06-17 2006-04-06 Science Applications International Corporation Toroidal propulsion and steering system
US7044245B2 (en) * 2003-06-17 2006-05-16 Science Applications International Corporation Toroidal propulsion and steering system
CN100396534C (zh) * 2006-11-24 2008-06-25 湖南农业大学 履带式多路况自动变形轮
US20080284245A1 (en) * 2007-05-18 2008-11-20 Caterpillar Inc. Machine track system and machine track segment
US20090051218A1 (en) * 2007-08-24 2009-02-26 Crooks Jeffrey J A Traction Enhancement Device
US7658455B2 (en) * 2007-08-24 2010-02-09 Crooks Jeffrey J A Traction enhancement device
US9033430B2 (en) * 2009-04-29 2015-05-19 Camoplast Solideal Inc. Track assembly for an all-terrain vehicle (ATV) or other tracked vehicle
US20100276990A1 (en) * 2009-04-29 2010-11-04 Camoplast Inc. Track assembly for an all-terrain vehicle (atv) or other tracked vehicle
US9211922B2 (en) 2012-08-17 2015-12-15 Cardinal Gibbons High School Robotic vehicle having traction and mobility-enhanced wheel structures
US20140156105A1 (en) * 2012-11-30 2014-06-05 Caterpillar Inc. Conditioning a Performance Metric for an Operator Display
US8965640B2 (en) * 2012-11-30 2015-02-24 Caterpillar Inc. Conditioning a performance metric for an operator display
US20140306516A1 (en) * 2013-04-16 2014-10-16 Caterpillar Inc. Vibration-damped track shoe for mobile machine
US9676431B2 (en) 2013-05-24 2017-06-13 Harnischfeger Technologies, Inc. Crawler track
US9776676B2 (en) 2013-11-12 2017-10-03 Harnischfeger Technologies, Inc. Guide rail for crawler track
US9988110B2 (en) 2013-11-12 2018-06-05 Joy Global Surface Mining Inc Guide rail for crawler track
USD748153S1 (en) 2014-05-22 2016-01-26 Harnischfeger Technologies, Inc. Crawler track shoe
USD763931S1 (en) 2014-05-22 2016-08-16 Harnischfeger Technologies, Inc. Crawler track shoe
US20160176456A1 (en) * 2014-12-22 2016-06-23 Caterpillar Inc. Reversible Track Link System
US9751577B2 (en) * 2014-12-22 2017-09-05 Caterpillar Inc. Reversible track link system
US11241908B2 (en) * 2018-05-01 2022-02-08 Nicholas E. Mansfield Flex track

Also Published As

Publication number Publication date
ES385394A1 (es) 1974-03-16
DE2050972B2 (de) 1979-05-17
FR2070851B1 (es) 1976-02-06
ZA706450B (en) 1971-06-30
FR2070851A1 (es) 1971-09-17
DE2050972A1 (de) 1971-06-24
CH553683A (de) 1974-09-13
GB1320532A (en) 1973-06-13
DE2050972C3 (de) 1980-01-24
BE760306A (fr) 1971-06-14
CA919072A (en) 1973-01-16

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Owner name: CATERPILLAR INC., A CORP. OF DE.,ILLINOIS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CATERPILLAR TRACTOR CO., A CORP. OF CALIF.;REEL/FRAME:004669/0905

Effective date: 19860515

Owner name: CATERPILLAR INC., 100 N.E. ADAMS STREET, PEORIA, I

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:CATERPILLAR TRACTOR CO., A CORP. OF CALIF.;REEL/FRAME:004669/0905

Effective date: 19860515