Classifications

• • 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
  • B62D55/18—Tracks
  • B62D55/20—Tracks of articulated type, e.g. chains
  • B62D55/205—Connections between track links

Definitions

• This invention relates generally to an endless track for crawler-type vehicles and more particularly to apparatus for retaining a joint of such track.
• a track joint is customarily held together by an interference fit between the ends of the track pins and their respective link bores into which the pin ends are received. While a substantial force, sometimes exceeding 60 tons (54.4 metric tons), is typically used to press the links onto their respective pin ends, the links still have a tendency to move outwardly on the pin as a result of forces exerted on the track during operation of the vehicle.
• a joint of an endless track for a crawler- type vehicle has a pin and a pair of links.
• the pin has opposite ends and first and second end portions.
• the links each having a bore of a size sufficient for receiving a respective one of the first and second pin end portions.
• Each of the first and second pin end portions have a groove. Each groove is spaced a preselected distance from a respective one of the opposite pin ends.
• Each of the links is provided with a socket adjacent the link bore. Each socket is in substantial registry along an interface with a
• an endless track is assembled by the steps of placing a pair of metal preforms adjacent an opening of each of the retainer cavities and forcing a preform into each cavity and deforming the preform into tight contact with the walls of the cavity to provide a formed-in-place retainer.
• a joint of an endless track is repaired by the steps of pushing the pin out of the link end portion, shearing the formed-in-place retainer, removing the sheared retainer from its retainer cavity, replacing the pin end portion in its link end portion, placing a metal preform adjacent the cavity opening, forcing the preform into the cavity and deforming the preform into a new formed-in-place retainer.
• the formed-in-place retainer has, in its deformed state, a modulus of elasticity preferably in excess of 25 million pounds per square inch (172,000 MPa) and is tightly intruded into the retainer cavity between a surface in the link socket and an opposite surface in the pin groove to provide a rigid lock between the pin and link, thereby limiting end play movement.
• Fig. 1 is a fragmentary plan view of an endless track with a portion of a joint thereof in section illustrating an embodiment of the retaining apparatus
• Fig. 2 is a frontal view of a preferred embodiment of the preform
• Fig. 3 is a side view of the preform of Fig. 2;
• Fig. 4 is an enlarged sectional view of one end of the joint illustrated in Fig. 1;
• Fig. 5 is a greatly enlarged fragmentary sectional view of the apparatus shown in Fig. 1;
• Fig. 6 is a view similar to Fig. 5, but illustrating a preform as it would appear entering the retainer cavity before deformation;
• Fig. 7 is a force/displacement curve of a preferred embodiment of the formed-in-place retainer.
• Fig. 8 is an enlarged- sectional view similar to Fig. 4, but illustrating the formed-in-place retainer as it would appear when being sheared in response to removing the pin.
• apparatus embodying the principals of the present invention is generally depicted at 10 for rigidly retaining a joint 12 of an endless track 14 of the type used on a crawler-type vehicle, not shown.
• the endless track 14 is generally of a conventional design, the major components of which include a plurality of right-hand links 16,16' and left-hand links 18,18', pins 20 and hollow bushings 22.
• Each right-hand link 16,16' and left-hand link 18,18' has an inboard end portion 24,25, and an opposite outboard end portion 26,27, respectively.
• the inboard end portions 24,25 each have a bore 28 of a size sufficient to enable the inboard end portions to be press fitted onto the ends 30,32 of the bushing 22.
• the pins 20 have a mid-portion 34, opposite ends 36 and 38 and opposite end portions 40 and 42.
• the pin mid-portion 34 is of a size to be received within the hollow bushing 22 and freely pivot relative to the bushing.
• each bore 44 is of a size sufficient to enable the outboard end links portions
• a track of this configuration normally has each joint provided with a pair of seals, one of which is shown at 46, and a lubricant reservoir, such as a sealed bore 50 in the pin 20.
• each seal 46 is disposed within a counterbore 52 in each link outboard end portion 26 and 27.
• Lubricant in the reservoir 50 is communicated to the pivoting interface between the bushing 22 and the mid-portion 34 of the pin 20 by a cross hole 54 in the pin 20, as best shown in Fig. 1.
• a thrust ring 56 is disposed in each of the counterbores 52 so that all of the joint components can be pushed together into abutment without crushing the seals 46.
• the outboard link end portions 26 and 27 are in close abutting contact with adjacent ends of the thrust rings 56.
• the other ends of the thrust rings abut the adjacent opposite end of the bushing 22.
• the apparatus 10 is principally directed toward maintaining the above-described abutting relationship during operation of the crawler-type vehicle.
• the apparatus 10 includes a pair of retainer cavities 60 and 62, each cavity being of a shape and orientation to receive and deform a respective one of a pair of formed-in-place retainers 64 and 66.
• cavities 60,62 are mirror images of each other, only cavity 60 will be hereinafter described in detail with particular reference to Figs. 4 through 6, it being understood that such description applies to cavity 62.
• Cavity 60 is de ined by a pin groove 70 and a link socket 72.
• Groove 70 is formed in its respective pin end portion 40 and extends around at least a portion of the circumference of such end portion. While it should be understood that the groove 70 need be only partially .or in segments about the circumference of the pin, it is preferable that it be continuous or annular to avoid the waste of time, labor and equipment in machining the part.
• the groove 70 is disposed a preselected distance from the adjacent pin end 36. Such distance is related to the physical properties of the pin and is sufficient to provide the portion of the pin between its end 36 and the groove 70 with strength greater than_ that of the retainer 64. Maintaining this relative strength relationship functions to prevent damage or breakage of the pin during disassembly of the joint.
• the groove 70 preferably has a frustoconical surface 76, a bottom extremity 78 and a curvilinear side wall 80.
• the curvilinear side wall 80 extends from the cylindrical surface of the pin end portion 40 to the bottom extremity 78.
• the frustoconical surface 76 joins the curvilinear surface 80 adjacent the bottom extremity 78 and extends radially outwardly toward its peripheral edge adjacent the pin end 36.
• the frustoconical surface 76 is at an angle within a range of from between 20 to 30 degrees from its central axis, and preferably at an angle of approximately 25 degrees. The above configuration facilitates the substantially complete filling of the groove 70 by the retainer 64.
• the socket 72 is formed in the link outboard end portion 26.
• the socket 72 is disposed in registry along an imaginary interface 81 with pin groove 70 when link outboard end portion 26 is in its installed position on the pin end portion 40.
• the socket 72 can be of other configurations depending on various criteria, such as material hardness and configuration of the retainer preform.
• the socket 72 has at least a first frustoconical surface 82. This first frustoconical surface 82 is disposed in a spaced concentric relationship to the groove frustoconical surface 76 and extends radially inwardly from an outer side 84 of the link outboard end portion 26 toward the link bore 44.
• the cavity 60 has an annular opening 85 on the outer side 84.
• the first frustoconical surface 82 is preferably disposed at a second angle which is less than the angle of the groove frustoconical surface 76.
• This second angle is preferably within a range of 15 to 35 degrees, with an . . angle of about 20 degrees being preferable.
• Providing the first frustoconical surface 82 with an angle less than the angle of the groove frustoconical surface 76 advantageously produces a wedging action on the retainer 64 which facilities the loading of the retainer in shear on application of an axial force F, as shown in Fig. 5.
• the socket 72 preferably includes a second frustoconical surface 86 extending from the first frustoconical surface 82 to an inner peripheral edge 88 adjacent the link bore 44.
• the second frustoconical surface 86 is preferably at an angle of approximately 45 degrees which facilitates the intrusion of the retainer 64 into the groove 70.
• the formed-in-place retainers 64,66 are each identified as a preform 90, as shown in Figs. 2, 3, and 6. While the preform 90 is herein disclosed as being a continuous ring, split or segmented rings are intended to be included within the scope of the present invention. It should also be understood that the preform 90 may take other configurations with the following description being exemplary of the preferred configuration.
• the preform 90 has a generally rectangular cross-sectional configuration provided with a lead-in chamfer 92 about the periphery of one end thereof and a beveled face 94 on such end.
• the lead-in chamfer is preferably at the same angle as the first frustoconical surface 82 of the socket 72.
• the beveled face 94 is preferably at an angle such that it is parallel to the side wall 80 of the groove upon intrusion of the preform into the cavity 60 to facilitate filling of the groove 70.
• the preform 90 is preferably provided with a plurality of radially oriented slots 96.
• the slots 96 extend a preselected axial distance into the preform 90 from the beveled end face 94. This arrangement is advantageous during any required disassembly of the joint 12, as hereinafter described, and facilitates the intrusion of the preform 90 into the groove 70.
• the preform 90 is a ferrous material having a modulus of elasticity in the range of 19 to 30 million psi (131,000 to 207,000 MPa) .
• a preform 90 constructed from a wrought steel with a hardness in a range of from Rockwell B60 to C35 has been found to be preferred. It should be understood, however, that the hardness of the preform 90 must be less than the corresponding hardness of the materials of the link and pin forming the cavity 60.
• a ferrous powdered metal material can be satisfactorily used for the preform 90.
• Such powdered metal preform- 90 preferably has a minimum initial density of 6.8 grams per cubic centimeter. After installation, the powdered metal material preferably has a minimum density of 7.5 grams per centimeter.
• the hardness of the powdered metal preform 90 is preferably in a range of from Rockwell B40 to B100, with a preferred hardness of Rockwell B90.
• the links 16,16' and 18,18', pins 20 and bushings 22 are assembled in the manner described above.
• a preform 90 is thereafter placed adjacent the annular opening 85 of the cavity 60.
• a sufficient force as by means of a press 97, is then applied to the preform 90 to ram the preform 90 into the cavity 60 resulting in the preform 90 being plastically deformed and intruded into its formed-in-place retainer shape substantially conforming to the shape of the cavity 60.
• a force in the range of. 100,000 to 200,000 pounds (445 to 890 kN) is normally required, with a force of approximately 150,000 pounds (667 kN) being typical.
• the retainer 64 Because of its high modulus of elasticity, the retainer 64 is substantially rigid, thus preventing any significant outward axial movement of the outboard end portion 26 on the pin end portion 40.
• a second preform 90 is similarly pressed into its cavity 62 at the other end of the joint 12.
• the powdered metal retainer had a modulus of elasticity of about 19 million psi (131,000 MPa) before deformation, and about 25 million psi (172,000 MPa) after deformation. This increase in modulus of elasticity was in response to the increase in density resulting from the large deformation force applied during intrusion of the preform 90 into the cavity.
• the shear force carrying capability of the retainer 64 can be varied.
• the retainer 64 can be designed in accordance with the actual forces which will be experienced during operation of the various sizes of crawler vehicles. Shear force capability can thereby be maintained at a value greater than the operational forces.
• an endless track 14 " constructed in accordance with the present invention will have joints 12 which have virtually no end play during operation of the crawler-type vehicle.
• the material of the retainer 64 has a high modulus of elasticity. This produces a force/displacement curve 98, as depicted in Fig. 7, having a steep sloped straight line portion 100 which
• the retainer 64 is in the elastic range of this material and an abrupt curved portion 102 in its plastic range.
• the retainer 64 can be designed to withstand operational forces approaching its elastic limit 104 without too great of an additional force being required to shear the retainer
• the retaining apparatus 10 of the present invention enables the track 14 to be disassembled for _ repair or replacement of worn components, such as the links 16,18 or bushings 22, and then be reassembled. As depicted in Fig. 8, this is accomplished by means of 30 a press 108 which pushes the pin 20 out of the link outboard end portions 26 and 27, while simultaneously shearing the formed-in-place retainers 64 and 66 along their respective interfaces 81. The sheared off portions of the retainers 64 and 66 are thereafter 35 removed from their corresponding grooves 70 and sockets 72. Removal from the grooves 70 is facilitated by the slots 96, shown in Figs. 2 & 3, which are preferably of a depth so as to extend past the interface 81.
• the portion of the preform 90 which had been intruded into the groove 70 becomes a plurality of pieces upon being sheared. Ordinarily, these pieces will simply fall out of the groove upon removal of the pin 20 from the joint 12.
• the track components are reassembled as they were initially and a new preform 90 is placed adjacent each of the openings 85 of the cavities 60 and 62. A force is applied to each of the preforms 90 to cause their intrusion into their respective cavities 60,62 and deformation into new formed-in-place retainers 64 and 66.
• a certain amount of end play can develop in the joint 12 due to internal wear between the axially abutting components of the joint 12. If this happens, the retainers 64 and 66 can advantageously be repressed to again eliminate this end play.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Snaps, Bayonet Connections, Set Pins, And Snap Rings (AREA)
• Absorbent Articles And Supports Therefor (AREA)
• Seal Device For Vehicle (AREA)
• Paper (AREA)
• Automatic Assembly (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23893746

Family Applications (1)

Country Status (10)

Cited By (2)

Families Citing this family (2)

Citations (7)

Family Cites Families (1)

• 1984
  • 1984-01-16 DE DE8484900785T patent/DE3461766D1/de not_active Expired
  • 1984-01-16 JP JP59500827A patent/JPS60500761A/ja active Granted
  • 1984-01-16 EP EP84900785A patent/EP0138838B1/en not_active Expired
  • 1984-01-16 AU AU24925/84A patent/AU564542B2/en not_active Ceased
  • 1984-01-16 BR BR8405358A patent/BR8405358A/pt not_active IP Right Cessation
  • 1984-01-16 WO PCT/US1984/000058 patent/WO1984003676A1/en not_active Ceased
  • 1984-02-15 CA CA000447532A patent/CA1212708A/en not_active Expired
  • 1984-03-12 IT IT20006/84A patent/IT1174516B/it active
  • 1984-03-15 MX MX200679A patent/MX159527A/es unknown
• 1989
  • 1989-09-18 SG SG64389A patent/SG64389G/en unknown

Patent Citations (7)

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