Patent Description:
A variety of machine tracks have been used for construction, mining and agricultural machines, military vehicles, conveyors and torque transmitting devices for well over a century. In general terms, a machine track consists of an endless chain of track links coupled together and extending about rolling elements. In the case of ground engaging tracks, such as those used to propel mobile machines, a toothed rotating element, commonly known as a drive sprocket, is often used to rotate a track about one or more idlers and a plurality of track rollers supporting the weight of the machine. Such tracks are in widespread use, and have earned a place as indispensable components of many machines operating in rugged environments. The durability, utility and resultant commercial success of tracks used in track-type machines is in large part a result of many decades of research and engineering of their numerous specialized components. While many designs have proven well-suited to rugged off-road environments, where track-type machines typically operate, a drawback to virtually all viable track designs is the difficulty in disassembling or "breaking" the track for service, part replacement or machine disassembly.

One design utilizes pins to couple track links together to form sets of parallel endless track chains. In certain of these designs, a single pin couples together an inboard link and an outboard link in each of the parallel chains. Track shoes coupled with the respective chains provide the elements which engage the ground for propelling the machine. Press fits are often used to provide a robust connection between the pin and the associated track links. To disassemble most tracks having press fits, and particularly those having S-shaped links, a relatively large hydraulic press is typically required to press the pin out of the track. Even after removing the pin, seals used to retain lubricating fluid and protect components from entry of foreign material may resist further disassembly of the track, necessitating the use of an additional hydraulic press to complete track disassembly at a given joint. Great care is often required to avoid damaging the track components during disassembly. Tracks having straight links are often serviced by pulling outboard links off of the ends of track pins rather than pressing out the pins.

Due to the time, care and specialized tools required to disassemble machine track, it has become common to use master links in a track. While master links provide relatively easier disassembly of a track at a given joint, they often still require specialized tools and provide only a single point at which the track can be broken. Master links are also relatively extensively machined parts, and hence expensive, and in some instances can create a weak point in the track. Additionally, master links are generally only able to be fit into a track from one side of the track.

<CIT>, titled "Crawler belt coupling apparatus," discloses a crawling belt coupling apparatus including first and second crawler belt links, a master pin, a locking pin, and a snap ring. However, this Patent cannot be assembled from either side of the continuous track and is not easy to assemble. Accordingly, a link pin is needed to which is both durable and easy to install in a link assembly.

The present disclosure is directed to one or more of the problems or shortcomings set forth above.

<CIT> discloses a crawler belt coupling apparatus including a first crawler belt link, a second crawler belt link, a master pin, a locking pin, and a snap ring. The master pin is inserted in first and second through holes. The master pin is provided with an insertion hole. The locking pin is press fitted into the insertion hole, and has both ends projecting relative to the master pin. The snap ring has a C-like shape, has an outer diameter larger than the first through hole, is disposed opposite to the second crawler belt link relative to the first through hole, and is attached to the master pin. The groove has a width smaller than a diameter of the master pin. The locking pin is disposed in the groove.

<CIT> discloses a machine tread including a first and second pair of plates. The plates have corresponding first ends and second ends, and the second ends of the first pair include outer bores. The first ends of the second pair include aligned bushing bores. The first ends of the second pair fit between the second ends of the first pair, aligning the outer and bushing bores. Ends of a bushing including an inner bore engage the bushing bores forming a pin bore through the inner and outer bores. A retention pin fits in the segmented pin bore. A head end abuts an external surface of the first pair of plates and a locking end extends past the pin bore. A retention cap engages the locking end. A dowel pin fits through a dowel pin bore in the retention cap and the locking end to limit movement of the retention pin.

There are provided master link boxes for a continuous track of a work machine. The master link boxes include a left-hand master link having a first distal surface, a first proximal surface opposite the first distal surface, a first pin bore extending between the first distal surface and the first proximal surface, a first link seal bore, and a first lateral annular recess disposed around the first pin bore and inset from the first distal surface and a right-hand master link having a second distal surface, a second proximal surface opposite the second distal surface, a second pin bore extending between the second distal surface and the second proximal surface, a second link seal bore, and a second lateral annular recess disposed around the second pin bore and inset from the second distal surface. The master link boxes also include a master link pin receivable in the first pin bore and the second pin bore. The master link pin includes a distal end, a proximal end opposite the distal end, an outer circumferential surface, a distal annular groove in the outer circumferential surface near the distal end, and a radial projection near the proximal end having a projection surface extending outwardly from the outer circumferential surface. The master link boxes further include a master retaining ring disposed in the distal annular groove. To assemble the master link box, the master link pin is configured to be first inserted through either the left-hand master link or the right-hand master link and subsequently secured in place by the master retaining ring. The projection surface abuts one of the first lateral annular recess and the second lateral annular recess when the master link box is assembled.

There are further described, not falling within the scope of the claims, methods for forming a continuous track for a work machine. The methods include the steps of providing a plurality of track link boxes forming a link assembly having a first end and a second end and providing a master link box between the front end and the rear end of the link assembly. The master link box includes a left-hand master link having a first pin bore and a first link seal bore, a right-hand master link having a second pin bore and a second link seal bore, a master link bushing, a master link pin having a distal annular groove near a distal end and a radial projection near a proximal end, and a master retaining ring. The methods also include the steps of securing the first link seal bore and the second link seal bore to the first end of the link assembly, securing the master link bushing between two link seal bores of a track link box defining the second end of the link assembly, aligning the first pin bore and the second pin bore with the master link bushing, inserting the master link pin through one of the first pin bore and the second pin bore, through the master link bushing, and into the other of the first pin bore and second pin bore, and securing the master retaining ring in the distal annular groove of the master link pin.

Further features and advantages of the invention will become apparent from the description of embodiments using the accompanying drawings. In the drawings:.

While the following detailed description will be given with respect to certain illustrative embodiments, it should be understood that the drawings are not necessarily to scale and the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In addition, in certain instances, details which are not necessary for an understanding of the disclosed subject matter or which render other details too difficult to perceive may have been omitted. It should therefore be understood that this disclosure is not limited to the particular embodiments disclosed and illustrated herein, but rather to a fair reading of the entire disclosure and claims, as well as any equivalents thereto.

Referring to <FIG>, there is shown a work machine <NUM> according to one embodiment. The work machine <NUM> may include a frame <NUM> and one or more tracks <NUM> coupled with frame <NUM>. In the illustrated embodiment, the work machine <NUM> is a high drive track-type tractor, including a pair of identical tracks <NUM> identical to the first track <NUM> disposed on opposite side of the frame <NUM>. However, it will be appreciated that the work machine <NUM> may be any other machine with a continuous track. For example, the work machine <NUM> may be a half-track machine, an excavator, a tank, some other type of mobile machine, or even a stationary machine such as a conveyor might be constructed according to the teachings set forth herein.

Each track <NUM> may comprise an endless track extending about a plurality of rotatable elements, including for example a drive sprocket <NUM>, a back idler <NUM> and a front idler <NUM>, as well as a plurality of track rollers <NUM>. The track <NUM> may further include a plurality of coupled together track link boxes <NUM> forming two parallel track chains, coupled with track shoes in a conventional manner. In <FIG>, an exemplary track link box <NUM> is shown including a first or left-hand track link <NUM>, a second or right-hand track link <NUM>, a bushing <NUM> disposed between the left-hand and right-hand track links <NUM>, <NUM>, and a track link pin <NUM> which may join the left-hand track link <NUM>, bushing <NUM>, and right-hand track link <NUM>.

As shown in <FIG>, the left-hand and right-hand track links <NUM>, <NUM> are generally elongated ovals having a first end <NUM>, a second end <NUM>, a distal surface <NUM>, a proximal surface <NUM>, and a top surface <NUM>. The track links <NUM>, <NUM> may be substantially mirror images of one another and oriented substantially parallel to one another in the track link box <NUM>. In one embodiment, the left-hand and right-hand track links <NUM>, <NUM> are off-set links with the first ends <NUM> being flared or tapered distally outward and the second ends <NUM> being flared or tapered proximally inward from the remainder of each track link <NUM>, <NUM>. The first end <NUM> may flare outwardly and the second end <NUM> may flare inwardly to an extent such that the second ends <NUM> of one pair of track links <NUM>, <NUM> may be disposed between the first ends <NUM> of an adjacent pair of track links <NUM>, <NUM> when the adjacent link boxes <NUM> are aligned.

While the track links <NUM>, <NUM> have been described as off-set links, the track links <NUM>, <NUM> may take a variety of shapes and configurations. For example, the track links <NUM>, <NUM> may be straight links with alternating pairs of inside and outside links, S-shaped links, or any other suitable configuration of links.

The track links <NUM>, <NUM> may have a first or pin bore <NUM> extending through the first end <NUM> and a second or link seal bore <NUM> extending through the second end <NUM>. The pin bore <NUM> may be a circular bore sized to receive a portion of the track link pin <NUM> and the link seal bore <NUM> may be a circular bore sized to receive a portion of the bushing <NUM>. In a preferred embodiment, the pin bore <NUM> and link seal bore <NUM> are unthreaded.

The track links <NUM>, <NUM> may also include one or more track shoe bores <NUM> disposed in the top surface <NUM> and extending partially into the track links <NUM>, <NUM>. The track shoe bores <NUM> are each threaded and sized to at least partially receive a track shoe fastener <NUM> to secure a track shoe <NUM> (<FIG>) to the track links <NUM>, <NUM>. In a preferred embodiment, the track shoe fastener <NUM> is a threaded bolt which extends through the track shoe <NUM> and into the track shoe bores <NUM> to secure the track shoe <NUM> to the track links <NUM>, <NUM>.

As shown in <FIG>, the bushing <NUM> is a generally hollow cylinder having a first opening <NUM>, a second opening <NUM> opposite the first opening (not shown), a cylindrical inner surface <NUM>, and a cylindrical outer surface <NUM>. The cylindrical outer surface <NUM> may be tapered radially inward near the first and second openings <NUM>, <NUM> such that the ends of the bushing <NUM> may be securely received within the link seal bores <NUM> of the track links <NUM>, <NUM>. The cylindrical inner surface <NUM> defines a bore having an inner diameter which may be sized to receive the track link pin <NUM> and allow the track link pin <NUM> to rotate within the cylindrical inner surface <NUM>. While the cylindrical outer surface <NUM> is illustrated as being tapered, the bushing <NUM> may have other designs. For example, the cylindrical outer surface <NUM> may have a stepped outer diameter wherein the cylindrical outer surface <NUM> has a first diameter that is constant along the length of the bushing <NUM> near the first and second openings <NUM>, <NUM> and a second diameter that is constant along the length of the bushing <NUM> between the portions having the first diameter, or any other suitable geometry.

Referring to <FIG>, the track link pin <NUM> is a substantially cylindrical rod having a distal end <NUM>, a proximal end <NUM>, and an outer circumferential surface <NUM>. The track link pin <NUM> is sized and shaped to be at least partially inserted through the pin bores <NUM> of the track links <NUM>, <NUM> and through the cylindrical inner surface <NUM> of the bushing <NUM>.

As shown in <FIG>, the track link pin <NUM> may have a flared end or radial flange or projection <NUM> projecting radially outward from the outer circumferential surface <NUM> at or near the proximal end <NUM>. The radial projection <NUM> has a projection surface <NUM> extending outwardly from the outer circumferential surface <NUM> and a radial outer surface <NUM> substantially concentric with the outer circumferential surface <NUM> and extending between the projection surface <NUM> and the proximal end <NUM>.

Turning back to <FIG>, the track links <NUM>, <NUM> may include a lateral annular recess <NUM> disposed around the pin bores <NUM> and inset from the distal surface <NUM> and a medial annular recess <NUM> disposed around the pin bores <NUM> and inset from the proximal surface <NUM>. The lateral annular recess <NUM> may be sized to receive the radial projection <NUM> of the track link pin <NUM>, as detailed below. The lateral annular recess <NUM> may be substantially the same width or slightly larger than the radial projection <NUM> and the lateral annular recess <NUM> may be inset from the distal surface <NUM> to substantially the same depth as the length of the radial projection <NUM> extending between the projection surface <NUM> and the proximal end <NUM>. The medial annular recess <NUM> may be sized to partially receive the bushing <NUM>. The medial annular recess <NUM> may be substantially the same width or slightly larger than the cylindrical outer surface <NUM> of the bushing <NUM> near the first and/or second opening <NUM>, <NUM> of the bushing <NUM>. The medial annular recess <NUM> may also be recessed from the proximal surface <NUM> such that a load ring <NUM>, a seal ring <NUM> having a seal lip <NUM>, and a thrust ring <NUM> may be disposed between the bushing <NUM> and each of the track link <NUM>, <NUM> when the track link box <NUM> is assembled, as detailed below. While the medial annular recess <NUM> has been as being recessed such that the track link box <NUM> may include a load ring <NUM>, a seal ring <NUM>, and a thrust ring <NUM>, it will be appreciated that other seals, rings, or seal rings, or any combination thereof, may be utilized. For example, the medial annular recess <NUM> may be recessed such that the track link box <NUM> may include a thrust ring and an oil seal, a grease seal, or any other suitable seals or seal rings.

As shown in <FIG>, the track link pin <NUM> may include one or more annular grooves <NUM> in the outer circumferential surface <NUM> near the distal and/or proximal ends <NUM>, <NUM>. The annular grooves <NUM> may be recessed from the outer circumferential surface <NUM>. In the illustrated embodiment, the annular grooves <NUM> are rounded. However, it will be appreciated that other embodiments are contemplated. For example, the annular grooves <NUM> may be triangular, rectangular, or any other suitable design.

The track link box <NUM> may also include one or more retaining rings <NUM> disposed in the annular grooves <NUM> of the track link pin <NUM>. The retaining rings <NUM> may be disc-shaped and sized to securely fit in the annular grooves <NUM> of the track link pin <NUM>. The retaining rings <NUM> may be larger than the pin bores <NUM> of the track links <NUM>, <NUM>. When the track link pin <NUM> is inserted in the track link box <NUM>, the retaining rings <NUM> may be disposed in the annular grooves <NUM> of the track link pin <NUM> to retain the track link pin <NUM> in the track link box <NUM>. In a preferred embodiment, the retaining rings <NUM> are press fit into the annular grooves <NUM>.

As shown in <FIG>, the track link pin <NUM> may include a longitudinal bore <NUM> extending longitudinally into the track link pin <NUM> from the distal end <NUM> and a side fluid passage <NUM> extending radially outward from the longitudinal bore <NUM> to the outer circumferential surface <NUM>. As such, the outer circumferential surface <NUM>, the side fluid passage <NUM>, the longitudinal bore <NUM>, and the distal end <NUM> of the track link pin <NUM> may be fluidly connected. The track link pin <NUM> may also include a cap <NUM> which may be inserted into the longitudinal bore <NUM> from the distal end <NUM> to close off or otherwise seal the longitudinal bore <NUM> from the distal end <NUM>. In one embodiment, the cap <NUM> is a screw or other fastener which may be threaded or otherwise secured in the longitudinal bore <NUM> from the distal end <NUM> to seal off the longitudinal bore <NUM>.

While the track link pin <NUM> has been described as having one or more annular grooves <NUM> which may receive a retaining ring <NUM>, a longitudinal bore <NUM>, a side fluid passage <NUM>, and a cap <NUM>, other embodiments may be contemplated. For example, if grease is used as a lubricant within the track link box <NUM>, as detailed below, the track link pin <NUM> may have a substantially smooth outer circumferential surface <NUM> without annular grooves <NUM> and the track link box <NUM> may not include retaining rings <NUM> to secure the track link pin <NUM> in the track link box <NUM>. Also, if grease is used as a lubricant within the track link box <NUM>, the track link pin <NUM> may be a substantially solid rod without any internal passages or bores or a cap.

As shown in <FIG>, the track link pin <NUM> may also include a first counterbore <NUM> disposed in the distal end <NUM> and/or a second counterbore <NUM> disposed in the proximal end <NUM>. The first and second counterbores <NUM>, <NUM> may extend partially into the track link pin <NUM> and may make the track link pin <NUM> easier to assemble and/or may prevent dirt or other debris from collecting in the track link box <NUM>. In the illustrated embodiment, the first and second counterbores <NUM>, <NUM> are relatively conical. However, it will be appreciated that other embodiments are contemplated. For example, the first and/or second counterbores <NUM>, <NUM> may be rounded, triangular, rectangular, pentagonal, or any other suitable shape.

While the track link pin <NUM> has been described as having a first counterbore <NUM> disposed in the distal end <NUM>, it will be appreciated that other embodiments are contemplated. For example, if the track link pin <NUM> includes a longitudinal bore <NUM>, a side fluid passage <NUM>, and a cap <NUM>, the track link pin <NUM> may not have a first counterbore <NUM> disposed in the distal end <NUM>.

Referring to <FIG>, a first or inside pair of track links <NUM>, <NUM> may be joined to a second or outside pair of track links <NUM>, <NUM> to form a link assembly <NUM>. The link seal bores <NUM> of the first or inside pair of track links <NUM>, <NUM> may be fittingly secured to the cylindrical outer surface <NUM> of the bushing <NUM> at or near the first and second openings <NUM>, <NUM> of the bushing <NUM>. The link seal bores <NUM> may be press fit onto the bushing <NUM> by use of a tool or machine, such as a hydraulic press. However, the link seal bores <NUM> of the track links <NUM>, <NUM> may be secured or otherwise attached to the bushing <NUM> by any other suitable means.

The pin bores <NUM> of the second or outside pair of track links <NUM>, <NUM> may then be aligned with the first and second openings <NUM>, <NUM> of the bushing <NUM> and/or the link seal bores <NUM> of the first pair of track links <NUM>, <NUM>. The track link pin <NUM> may then be inserted through the pin bore <NUM> of either the left-hand or right-hand track link <NUM>, <NUM> of the outside pair, through the bushing <NUM>, and into the pin bore <NUM> of the other track link <NUM>, <NUM> of the outside pair. The track link pin <NUM> may be inserted through the pin bores <NUM> and the bushing <NUM> until the projection surface <NUM> of the track link pin <NUM> abuts the annular recess <NUM> of the track link <NUM>, <NUM> through which the track link pin <NUM> was first inserted. The track link pin <NUM> may be press-fit into the pin bores <NUM> and bushing <NUM> by use of a tool or machine, such as a hydraulic press. However, the track link pin <NUM> may be secured or otherwise inserted through the pin bores <NUM> and the bushing <NUM> by any other suitable means. The track link pin <NUM> may secured, if at all, only to the pin bores <NUM> of the outside pair of track links <NUM>, <NUM> such that the track link pin <NUM> and the outside pair of track links <NUM>, <NUM> secured to the track link pin <NUM> may rotate independently from the bushing <NUM> and the inside pair track links <NUM>, <NUM> secured to the bushing <NUM> about an axis extending through the track link pin <NUM>. Once the track link boxes <NUM> are secured to an adjacent track link box <NUM>, track shoes <NUM> may be secured to the top surface <NUM> of the track links <NUM>, <NUM> by inserting the one or more track shoe fasteners <NUM> through the track shoe <NUM> and into the one or more track shoe bores <NUM>.

As shown in <FIG>, the link seal bores <NUM> of the first pair or inside pair of track links <NUM>, <NUM>, the ends of the bushing <NUM>, the load rings <NUM>, the seal rings <NUM>, the thrust rings <NUM>, and the outer circumferential surface <NUM> of the track link pin <NUM> may form a fluid seal when the track link pin <NUM> is inserted through the link seal bores <NUM> and the bushing <NUM>. The load ring <NUM> may provide a thrust load or similar force onto the seal ring <NUM> which pushes or presses the seal lip <NUM> of the seal ring <NUM> against the end of the bushing <NUM> to form a fluid seal between the bushing <NUM> and the track links <NUM>, <NUM>. The thrust ring <NUM> separates the bushing <NUM> and the medial annular recess <NUM> of the track links <NUM>, <NUM> to protect the load ring <NUM> and seal ring <NUM>. As a result, when the track link pin <NUM> is inserted in the track link box <NUM>, a sealed link cavity <NUM> is formed between the cylindrical inner surface <NUM> of the bushing <NUM>, the outer circumferential surface <NUM> of the track link pin <NUM>, the load rings <NUM>, the seal rings <NUM>, and the thrust rings <NUM>. While the track link box <NUM> has been described as having load rings <NUM>, seal rings <NUM>, and thrust rings <NUM> which form the sealed link cavity <NUM>, it will be appreciated that other seals, rings, and seal rings or combinations thereof may be used to form the sealed link cavity <NUM>. For example, the track link box <NUM> may use a thrust ring and an oil seal, such as when the track link pin <NUM> includes a longitudinal bore <NUM>, a grease seal, such as when the track link pin <NUM> does not include a longitudinal bore <NUM>, or any other suitable seals, rings, or seal rings, or any combination thereof.

Before the track link pin <NUM> is fitted into the pin bores <NUM> and bushing <NUM>, a lubricant <NUM>, such as grease, oil, or any other suitable lubricant, may be inserted into the sealed link cavity <NUM> to facilitate the rotation of the track link pin <NUM> within the bushing <NUM>, reduce friction and/or wear of the bushing <NUM> and/or track link pin <NUM>, and reduce heat generation.

In a first embodiment, the lubricant <NUM> may be inserted into the sealed link cavity <NUM> and/or the bushing <NUM> before the track link pin <NUM> is inserted into the track link box <NUM> or after the track link pin <NUM> has been partially inserted into the track link box <NUM> but before the track link pin <NUM> is fully inserted into the track link box <NUM>. As such, when the track link pin <NUM> is fully inserted in the track link box <NUM>, the lubricant <NUM> will be fluidly sealed within the sealed link cavity <NUM> of the track link box <NUM>.

In a second embodiment where the track link pin has a longitudinal bore <NUM> and side fluid passage <NUM> (<FIG>), such as when the lubricant <NUM> is oil, the lubricant <NUM> may be inserted into the longitudinal bore <NUM> of the track link pin <NUM> after the track link pin <NUM> has been inserted into the track link box <NUM> such that the lubricant <NUM> flows through the side fluid passage <NUM> and into the sealed link cavity <NUM>. After a sufficient amount of lubricant <NUM> has been added into the sealed link cavity <NUM>, the cap <NUM> may be inserted into the longitudinal bore <NUM> to seal the longitudinal bore <NUM> and thereby retain the lubricant <NUM> in the sealed link cavity <NUM>.

After the track link pin <NUM> has been inserted through the pin bore <NUM> of one of the track links <NUM>, <NUM>, the bushing <NUM>, and the other track link <NUM>, <NUM>, retaining rings <NUM> may be secured into the annular grooves <NUM> of the track link pin <NUM> through which the distal end <NUM> of the track link pin <NUM> extends. As the retaining rings <NUM> are larger than the pin bores <NUM> of the track links <NUM>, <NUM>, the retaining rings <NUM>, when secured in the annular groove <NUM>, will prevent the distal end <NUM> of the track link pin <NUM> from being retracted through the pin bore <NUM> of the track link <NUM>, <NUM> through which the distal end <NUM> of the track link pin <NUM> extends. In such a manner, the retaining ring <NUM> may secure the track link pin <NUM> in the track link box <NUM>.

The process of joining track links <NUM>, <NUM> together to form the link assembly <NUM> may be repeated using additional pairs of track links <NUM>, <NUM>, bushings <NUM>, and track link pins <NUM> until the link assembly <NUM> is substantially the length of the continuous track <NUM>. In a preferred embodiment, the process is repeated until the link assembly <NUM> is just one track link box <NUM> short of the desired length of the continuous track <NUM>.

The resulting link assembly <NUM> is a substantially straight chain of link boxes <NUM> and has a first or front end <NUM> and a second or rear end <NUM>. In a preferred embodiment, the front end <NUM> of the link assembly <NUM> consists of the first ends <NUM> of the track links <NUM>, <NUM> of the front link box <NUM> such that the pin bores <NUM> of the front track links <NUM>, <NUM> are exposed and the rear end <NUM> of the link assembly <NUM> consists of the second ends <NUM> of the track links <NUM>, <NUM> of the rear link box <NUM> such that link seal bores <NUM> of the rear track links <NUM>, <NUM> are fit together and may be aligned and joined with the pin bores <NUM> of subsequent track links <NUM>, <NUM>. It will be appreciated that the terms front end and rear end in relation to the link assembly <NUM> are descriptions used to clarify the illustrations and the front end <NUM> of the link assembly <NUM> may be disposed at the rear of the link assembly <NUM> and the rear end <NUM> of the link assembly <NUM> may be disposed at the front of the link assembly <NUM>.

Turning now to <FIG> and <FIG>, a master link box <NUM> may be joined to the front and rear ends <NUM>, <NUM> of the link assembly <NUM> to form a continuous track <NUM>. The master link box <NUM> may include a first or left-hand master link <NUM>, a second or right-hand master link <NUM>, a master link bushing <NUM>, a master link pin <NUM>, and a master retaining ring <NUM>.

As shown in <FIG> and <FIG>, the master links <NUM>, <NUM> are similar in size and shape to the track links <NUM>, <NUM>. Similarly to the track links <NUM>, <NUM>, the master links <NUM>, <NUM> each have a first end <NUM> that is flared outwardly, a second end <NUM> that is flared inwardly, a distal surface <NUM>, a proximal surface <NUM>, a top surface <NUM>, a pin bore <NUM> extending through the first end <NUM>, a link seal bore <NUM> (not shown) extending through the second end <NUM>, a lateral annular recess <NUM> disposed around the pin bore <NUM> and inset from the distal surface <NUM>, a medial annular recess <NUM> disposed around the pin bore <NUM> and inset from the proximal surface <NUM>, and at least one track shoe bore <NUM> in the top surface <NUM>. The at least one track shoe bores <NUM> in the top surface <NUM> may extend partially into the master links <NUM>, <NUM> which may receive the track shoe fasteners <NUM> (<FIG>) to secure the track shoe <NUM> (<FIG>) to the master link box <NUM>. In a preferred embodiment, the continuous track <NUM> consists of a plurality of track link boxes <NUM> and a master link box <NUM>. However, it will be appreciated that other embodiments are contemplated. For example, the master links <NUM>, <NUM> may be used instead of the track links <NUM>, <NUM> in the remainder of the link assembly <NUM> or the link assembly <NUM> may be any other combination of track link boxes <NUM> and master link boxes <NUM>.

In the illustrated embodiment, the lateral annular recess <NUM> has a diameter between about <NUM> millimeters and about <NUM> millimeters, such as between about <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters. The pin bores <NUM> have a diameter between about <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters.

As shown in <FIG> and <FIG>, the master link bushing <NUM> may be a generally hollow cylinder having a first opening <NUM><NUM>, a second opening <NUM> (not shown) disposed opposite the first opening <NUM>, a cylindrical inner surface <NUM>, and a cylindrical outer surface <NUM>. The cylindrical inner surface <NUM> may be a substantially smooth bore and the cylindrical outer surface <NUM> may be tapered radially inward near the first and second openings <NUM>, <NUM> such that the ends of the master link bushing <NUM> may be securely received within the link seal bores <NUM> of the track links <NUM>, <NUM> defining the rear end <NUM> of the link assembly <NUM>, as detailed below. The cylindrical inner surface <NUM> defines a bore having an inner diameter which may be sized to receive the master link pin <NUM> and allow the master link pin <NUM> to rotate within the cylindrical inner surface <NUM>. While the cylindrical outer surface <NUM> is illustrated as being tapered, other shapes are contemplated. For example, the cylindrical outer surface <NUM> may have a stepped outer diameter wherein the cylindrical outer surface <NUM> has a first diameter that is constant along the length of the master link busing <NUM> near the first and second openings <NUM>, <NUM> and a second diameter that is constant along the length of the master link bushing <NUM> between the portions having the first diameter, or any other suitable geometry.

The master link bushing <NUM> of the master link box <NUM> may be substantially the same as the bushing <NUM> of the track link boxes <NUM>. However, the master link bushing <NUM> of the master link box <NUM> may be different than the bushings <NUM> of the track link boxes <NUM>.

Referring to <FIG>, the master link pin <NUM> is a generally cylindrical rod having a distal end <NUM>, a proximal end <NUM>, and an outer circumferential surface <NUM>. The distal and proximal ends <NUM>, <NUM> may be substantially circular and flat, and the proximal end <NUM> may be radially larger than the outer circumferential surface <NUM>. The master link pin <NUM> may have a radial flange or projection <NUM> extending radially outward from the outer circumferential surface <NUM> near the proximal end <NUM> which includes a projection surface <NUM> extending outwardly from the outer circumferential surface <NUM> and a radial outer surface <NUM> substantially concentric with the outer circumferential surface <NUM> and extending between the projection surface <NUM> and the proximal end <NUM>. In the illustrated embodiment, the projection surface <NUM> is perpendicular to the outer circumferential surface <NUM> However, it will be appreciated that other embodiments are contemplated. For example, the projection surface <NUM> may be angled toward the proximal end <NUM>, angled toward the distal end <NUM>, rounded, or any other suitable shape which may abut the master links <NUM>, <NUM> to prevent the master link pin <NUM> from being inserted too far through the master link box <NUM>, as detailed below. In one embodiment, the outer circumferential surface <NUM> is filleted, tapered, otherwise shaped near the distal end <NUM> to facilitate the insertion of the master link pin <NUM> to be placed into and through the pin bores <NUM> of the first and second master links <NUM>, <NUM> and the master link bushing <NUM>, as detailed below.

The master link pin <NUM> also includes a distal annular groove <NUM> disposed in and extending circumferentially around the outer circumferential surface <NUM> near the distal end <NUM>. The distal annular groove <NUM> is disposed a distance from the radial projection <NUM> that generally corresponds to the length between the lateral annular recesses <NUM> of the master links <NUM>, <NUM> when the master links <NUM>, <NUM> are arranged in the master link box <NUM>, as detailed below. The distal annular groove <NUM> may be recessed from the outer circumferential surface <NUM> and sized and shaped to receive the master retaining ring <NUM> or other securement member to secure the master link pin <NUM> in the master link box <NUM>. In the illustrated embodiment, the distal annular groove <NUM> is rectangular. However, it will be appreciated that the distal annular groove <NUM> may be other shapes. For example, the distal annular groove <NUM> may be rounded, triangular, oval, or any other suitable shape.

As shown in <FIG>, the master link pin <NUM> may also include a proximal annular groove <NUM> disposed in and extending circumferentially around the outer circumferential surface <NUM> near the proximal end <NUM> and/or the radial projection <NUM>. The proximal annular groove <NUM> may be recessed from the outer circumferential surface <NUM> to reduce the stress concentration on the master link pin <NUM> near the projection surface <NUM> when the master link pin <NUM> is inserted in the master link box <NUM> and the projection surface <NUM> abuts the lateral annular recess <NUM> of one of the master links <NUM>, <NUM>, as detailed below. The proximal annular groove <NUM> may also increases the ease of manufacture and assembly of the master link box <NUM>. In the illustrated embodiment, the proximal annular groove <NUM> is substantially rectangular with rounded corners and the wall of the proximal annular groove <NUM> nearest the proximal end <NUM> may form a part of or be coextensive with the projection surface <NUM> of the radial projection <NUM>. However, it will be appreciated that the distal annular groove <NUM> may have other designs. For example, the distal annular groove <NUM> may be rectangular, oval, triangular, elliptical, or any other suitable shape.

Referring back to <FIG>, the distal portion of the master link pin <NUM> near the distal end <NUM> may be radially tapered or narrowed to facilitate the placement of the master link pin <NUM> through the pin bores <NUM> of the master links <NUM>, <NUM> and the master link bushing <NUM>. In the illustrated embodiment, the outer circumferential surface <NUM> between the distal annular groove <NUM> and the distal end <NUM> is concentric with and has a smaller diameter than portion of the outer circumferential surface <NUM> between the distal annular groove <NUM> and the proximal annular groove <NUM>. However, the radial surface of the master link pin <NUM> near the distal end <NUM> may have other designs. For example, the outer circumferential surface <NUM> between the distal annular groove <NUM> and the distal end <NUM> may be tapered, angled, or rounded.

As shown in <FIG>, <FIG>, <FIG>, and <FIG>, the master link pin <NUM> may include a distal counterbore <NUM> disposed in the distal end <NUM> of the master link pin <NUM>. The distal counterbore <NUM> may extend from approximately the middle of the distal end <NUM> toward the proximal end <NUM> of the master link pin <NUM> to a depth substantially equivalent to or slightly further than the edge of the distal annular groove <NUM> closest to the proximal end <NUM>. The distal counterbore <NUM> may prevent dirt and other debris from accumulating in and around the distal annular groove <NUM> and thereby protects the distal annular groove <NUM> and the master retaining ring <NUM> disposed therein, as detailed below.

In the illustrated embodiment, the distal counterbore <NUM> is substantially conical with a first conical portion having a greater incline and extending farther into the master link pin <NUM> and a second conical portion having a lesser incline and extending only slightly farther into the master link pin <NUM> than the first conical portion. However, the distal counterbore <NUM> may have other designs. For example, the distal counterbore <NUM> may be rectangular, circular, rounded, triangular, curved, cylindrical, rectangular, hexagonal or any other suitable shape.

As shown in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, the master link pin <NUM> may also include a proximal counterbore <NUM> disposed in the proximal end <NUM> of the master link pin <NUM>. The proximal counterbore <NUM> may extend from approximately the middle of the proximal end <NUM> toward the distal end <NUM> of the master link pin <NUM> to a depth substantially equivalent to or slightly further than edge of the proximal annular groove <NUM> closest to the distal end <NUM>. The proximal counterbore <NUM> prevents dirt and other debris from accumulating in the lateral annular recess <NUM> of the master link <NUM>, <NUM> and between the master link <NUM>, <NUM>, the outer circumferential surface <NUM>, and the radial projection <NUM> of the master link pin <NUM>, and thereby protects the pin bores <NUM> of the master links <NUM>, <NUM> and the radial projection <NUM> of the master link pin <NUM>. The proximal counterbore <NUM> may also facilitates the placement of the master link pin <NUM> in the master link box <NUM> from either side of the master link box <NUM>, as detailed below.

In the illustrated embodiment, the proximal counterbore <NUM> is substantially a mirror image of the distal counterbore <NUM>. However, it will be appreciated that other embodiments are contemplated. For example, the proximal counterbore <NUM> may be rectangular, circular, rounded, triangular, curved, cylindrical, or any other suitable shape.

As shown in <FIG>, the master link pin <NUM> may include a longitudinal bore <NUM> extending longitudinally into the master link pin <NUM> from the distal end <NUM> and a side fluid passage <NUM> extending radially outward from the longitudinal bore <NUM> to the outer circumferential surface <NUM>. As such, the outer circumferential surface <NUM>, the side fluid passage <NUM>, the longitudinal bore <NUM>, and the distal end <NUM> of the master link pin <NUM> may be fluidly connected. The master link pin <NUM> may also include a cap <NUM> which may be inserted into the longitudinal bore <NUM> from the distal end <NUM> to close off or otherwise seal the longitudinal bore <NUM> from the distal end <NUM>. In a preferred embodiment, the cap <NUM> is a screw or other fastener which may be threaded or otherwise secured in the longitudinal bore <NUM> from the distal end <NUM> to seal off the longitudinal bore <NUM>.

While the master link pin <NUM> has been described as having a distal counterbore <NUM> disposed in the distal end <NUM>, it will be appreciated that other embodiments are contemplated. For example, if the master link pin <NUM> includes a longitudinal bore <NUM>, a side fluid passage <NUM>, and a cap <NUM>, the master link pin <NUM> may not have a distal counterbore <NUM> disposed in the distal end <NUM>.

In the illustrated embodiments, the master link pin <NUM> has a length extending between the distal and proximal ends <NUM>, <NUM> between about <NUM> millimeters and about <NUM> millimeters, such as between about <NUM> and about <NUM> millimeters, such as about <NUM> millimeters, and a diameter of the outer circumferential surface <NUM> between about <NUM> and about <NUM> millimeters, such as between about <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters. The distal annular groove <NUM> of the link pin is about <NUM> millimeters and has a length between about <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters. The radial projection <NUM> of the master link pin <NUM> has an outer diameter between about <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters. The distal annular groove <NUM> is between <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters, from the radial projection <NUM>. The proximal annular groove <NUM> has a length between about <NUM> millimeters and about <NUM>_, such as about <NUM> millimeters, and is recessed between about <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters, from the outer circumferential surface <NUM> of the master link pin <NUM>.

Referring to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, the master retaining ring <NUM> is a disk-shaped seal having a cylindrical inner surface <NUM>, a cylindrical outer surface <NUM>, a distal surface <NUM>, and a proximal surface <NUM>. The inner and outer surfaces <NUM>, <NUM> extend a distance between the distal and proximal surfaces <NUM>, <NUM>. The inner surface <NUM> of the master retaining ring <NUM> may be sized and shaped to be secured around the master link pin <NUM> in the distal annular groove <NUM>.

When secured or otherwise disposed in the distal annular groove <NUM> of the master link pin <NUM>, the master retaining ring <NUM> may extend out of the distal annular groove <NUM> such that the outer surface <NUM> of the master retaining ring <NUM> may extend beyond the outer circumferential surface <NUM> of the master link pin <NUM>. The outer surface <NUM> of the master retaining ring <NUM> may have a diameter that is larger than the inner diameter of the pin bores <NUM> of the master links <NUM>, <NUM>. In such a configuration, once the master retaining ring <NUM> is disposed in the distal annular groove <NUM>, the master retaining ring <NUM> may prevent the master link pin <NUM> from being retracted through the pin bore <NUM> of either master link <NUM>, <NUM>, depending on the side of insertion. The master retaining ring <NUM> may have a depth between the distal and proximal surfaces <NUM>, <NUM> substantially equivalent to the width of the distal annular groove <NUM> along the outer circumferential surface <NUM>. However, it will be appreciated that if the master retaining ring <NUM> has a depth less than the depth of the distal annular groove <NUM>, one or more master retaining rings <NUM> may be disposed within the distal annular groove <NUM> to secure the master link pin <NUM> in the master link box <NUM>.

in a preferred embodiment, the master retaining ring <NUM> is a triple wrap retaining ring which is a substantially straight piece of steel or other metal, such as tool steel or other resilient material, which is wrapped three times around the master link pin <NUM> in the distal annular groove <NUM>. In such an embodiment, the master retaining ring <NUM> may be secured or disposed in the distal annular groove <NUM> of the master link pin <NUM> without the use of a press fit tool or other tool to enlarge and/or resize the master retaining ring <NUM>. However, it will be appreciated that the master retaining ring <NUM> may have other designs. For example, the master retaining ring <NUM> may be a strip of steel which is wrapped one, two, or four or more times around the master link pin <NUM> or may be a solitary ring that is press-fit or sledged into the distal annular groove <NUM>.

In the illustrated embodiment, the master retaining ring <NUM> has a diameter of the inside surface <NUM> of about <NUM> and an outer diameter between about <NUM> millimeters and about <NUM> millimeters, such as between about <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters. The master retaining ring <NUM> has a thickness between the distal surface <NUM> and the proximal surface <NUM> between about <NUM> millimeters and about <NUM> millimeters, such as between about <NUM> millimeters and about <NUM> millimeters, such as about <NUM> millimeters.

As shown in <FIG> and <FIG>, the master link box <NUM> may also include one or more load rings <NUM>, one or more seal rings <NUM> having a seal lip <NUM>, and one or more thrust rings <NUM> disposed between the master link bushing <NUM> and the medial annular recesses <NUM> of the master links <NUM>, <NUM>. The load ring <NUM> may provide a thrust load or similar force onto the seal ring <NUM> which pushes or presses the seal lip <NUM> of the seal ring <NUM> against the ends of the master link bushing <NUM> to form a fluid seal between the master link bushing <NUM>, the master links <NUM>, <NUM>, and the master link pin <NUM> when the master link pin <NUM> is secured in the master link box <NUM>, as detailed below. The thrust rings <NUM> may separate the master link bushing <NUM> and the medial annular recess <NUM> of the master link <NUM>, <NUM> to protect the load ring <NUM> and the seal ring <NUM>. In a one embodiment, such as when the lubricant <NUM> is oil, the thrust ring <NUM> is made of a powdered metal, the load ring <NUM> is made of rubber, and the seal ring <NUM> is made of a polycarbonate material. In an alternative embodiment, such as when the lubricant is grease <NUM>, the seal ring <NUM> is made of urethane. However, it will be appreciated that the thrust ring <NUM>, load rings <NUM>, and seal rings <NUM> may be made from tool steel, polycarbonate, or any other suitable material.

Referring to <FIG>, the master link box <NUM> may be secured between the front and rear <NUM>, <NUM> ends of the link assembly <NUM> to form the continuous track <NUM>.

In one embodiment, the second or link seal bore <NUM> of the master links <NUM>, <NUM> are pre-joined onto the front end <NUM> of the link assembly <NUM>. The second ends <NUM><NUM> of the master links <NUM>, <NUM> may be connected with a bushing <NUM> by securing the link seal bores <NUM> of the master links <NUM>, <NUM> around the cylindrical outer surface <NUM> of the bushing <NUM>. The link seal bores <NUM> of the master links <NUM>, <NUM> and the bushing <NUM> may then be disposed and aligned with the pin bores <NUM> of the track links <NUM>, <NUM> defining the front end <NUM> of the link assembly <NUM>. One or more load rings <NUM>, one or more seal rings <NUM>, and one or more thrust rings <NUM> may be disposed between the bushing <NUM>, the medial annular recesses <NUM> of the track links <NUM>, <NUM>, and the master links <NUM>, <NUM>. Once the bores <NUM>, <NUM> are aligned, a track link pin <NUM> may be inserted through the track links <NUM>, <NUM> defining the front end <NUM> of the link assembly <NUM> and the bushing <NUM> secured between the master links <NUM>, <NUM> to join the front end <NUM> of the link assembly <NUM>, the bushing <NUM>, and the master links <NUM>, <NUM>. The track link pin <NUM> may be inserted and the master links <NUM>, <NUM> may be joined to the first ends <NUM> of the links <NUM>, <NUM> of the front link box <NUM> of the link assembly <NUM> by any other suitable means. For example, the track link pin <NUM> may be press-fit and sealed within the pin bores <NUM> of the front links <NUM>, <NUM>, the bushing <NUM>, and the link seal bores <NUM> of the master links <NUM>, <NUM>.

In a further embodiment, the master link bushing <NUM> may be pre-joined between the link seal bores <NUM> of the track links <NUM>, <NUM> defining the rear end of the link assembly <NUM> and the first ends <NUM> of the master links <NUM>, <NUM> are not pre-joined to the rear end <NUM> of the link assembly <NUM>. The master link bushing <NUM> may be secured between the link seal bores <NUM> of the track links <NUM>, <NUM> defining the rear end <NUM> of the link assembly <NUM> by press-fitting or any other suitable means. In such an embodiment, the link assembly <NUM> including the master link box <NUM> may be wrapped around the rotatable elements <NUM>, <NUM>, <NUM>, <NUM> of the work machine <NUM> and the first ends <NUM> of the master links <NUM>, <NUM> may be subsequently joined to the rear end <NUM> of the link assembly <NUM> when the track links <NUM>, <NUM> and master links <NUM>, <NUM> are in place and aligned to form the continuous track <NUM>.

To join the master link box <NUM> between the front and rear ends <NUM>, <NUM> of the link assembly <NUM> to form a continuous track <NUM>, the link seal bores <NUM> of the master links <NUM>, <NUM> may be secured to the front end <NUM> of the link assembly <NUM> by a track link pin <NUM>, as described above, and the pin bores <NUM> of the master links <NUM>, <NUM> may be aligned with the link seal bores <NUM> of the first and second track links <NUM>, <NUM> of the rear end <NUM> of the link assembly <NUM> with the master link bushing <NUM> secured therebetween. The distal end <NUM> of the master link pin <NUM> is then inserted or otherwise fit through the pin bore <NUM> of the left-hand or right-hand master link <NUM>, <NUM> from the distal surface <NUM>, through the master link bushing <NUM> (which is disposed between the link seal bores <NUM> of the track links <NUM>, <NUM>), and through the pin bore <NUM> of the other master link <NUM>, <NUM>. The master link pin <NUM> is inserted through one of the master links <NUM>, <NUM>, through the master link bushing <NUM>, and through the other master links <NUM>, <NUM> until the projection surface <NUM> of the radial projection <NUM> of the master link pin <NUM> abuts the lateral annular recess <NUM> of the master link <NUM>, <NUM> through which the distal end <NUM> of the master link pin <NUM> was first inserted.

As shown in <FIG>, the master link box <NUM> may include one or more load rings <NUM>, one or more seal rings <NUM>, and one or more thrust rings <NUM> disposed between the medial annular recesses <NUM> of the master links <NUM>, <NUM> and the master link bushing <NUM>. The load rings <NUM>, seal rings <NUM>, and thrust rings <NUM> may be disposed such that the load ring <NUM> may provide a thrust load or similar force onto the seal ring <NUM> which pushes or presses the seal lip <NUM> of the seal ring <NUM> against the end of the master link bushing <NUM> to form a fluid seal between the master link bushing <NUM>, the master links <NUM>, <NUM>, and the master link pin <NUM> when the master link pin <NUM> is secured in the master link box <NUM>. The thrust ring <NUM> may separate the master link bushing <NUM> and the medial annular recess <NUM> of the master link <NUM>, <NUM> to protect the load ring <NUM> and seal ring <NUM>. As a result, when the master link pin <NUM> is inserted into the master link box <NUM>, a sealed link cavity <NUM> is formed between the cylindrical inner surface <NUM> of the master link bushing <NUM>, the outer circumferential surface <NUM> of the master link pin <NUM>, the load rings <NUM>, the seal rings <NUM>, the thrust rings <NUM>, and the medial annular recess <NUM> and/or the pin bore <NUM> of the master links <NUM>, <NUM>.

While the master link box <NUM> has been described as having load rings <NUM>, seal rings <NUM>, and thrust rings <NUM> which form the sealed link cavity <NUM>, it will be appreciated that other seals, rings, and seal rings or combinations thereof may be used to form the sealed link cavity <NUM>. For example, the master link box <NUM> may include a thrust ring and an oil seal, such as when the master link pin <NUM> includes a longitudinal bore <NUM>, a grease seal, such as when the master link pin <NUM> does not have a longitudinal bore <NUM>, or any other suitable seals, rings, or seal rings, or any combination thereof.

The master link box <NUM> may also include lubricant <NUM> in the sealed link cavity <NUM>. The lubricant <NUM> may facilitate the rotation of the master link pin <NUM> within the master link bushing <NUM>, reduce friction and/or wear of the master link bushing <NUM> and/or master link pin <NUM>, and reduce heat generation. In a first exemplary embodiment, before the master link pin <NUM> has been fully inserted into the master link box <NUM>, the lubricant <NUM> may be inserted into the sealed link cavity <NUM> and/or in the master link bushing <NUM>. As such, when the master link pin <NUM> is fully inserted in the master link box <NUM>, the lubricant <NUM> will be fluidly sealed within the sealed link cavity <NUM> of the master link box <NUM>.

In second exemplary embodiment, such as when the lubricant <NUM> is oil and the master link pin <NUM> includes a longitudinal bore <NUM>, a side fluid passage <NUM>, and a cap <NUM>, the lubricant <NUM> may be added through the longitudinal bore <NUM> of the master link pin <NUM>, through the side fluid passage <NUM>, and into the sealed link cavity <NUM> of the master link box <NUM>. In such an embodiment, the lubricant <NUM> may be added at any time during the assembly of the master link box <NUM>, such as after the master link pin <NUM> has been fully inserted in the master link box <NUM>, as detailed below. After sufficient lubricant <NUM> has been added into the sealed link cavity <NUM> of the master link box <NUM>, the cap <NUM> may be inserted into the longitudinal bore <NUM> to seal the longitudinal bore <NUM> and thereby retain the lubricant <NUM> in the sealed link cavity <NUM>.

When the master link pin <NUM> has been fit through the pin bore <NUM> of the left-hand or right-hand master link <NUM>, <NUM>, the master link bushing <NUM>, and through the pin bore <NUM> of the other master link <NUM>, <NUM> until the radial projection <NUM> of the master link pin <NUM> abut the lateral annular recess <NUM> of the master link <NUM>, <NUM> through which the master link pin <NUM> was first inserted, the distal annular groove <NUM> will be disposed on the distal side of the pin bore <NUM> of the master link <NUM>, <NUM> through which the master link pin <NUM> was inserted second (the right-hand master link <NUM> in <FIG> and the left-hand master link <NUM> in <FIG>). The master retaining ring <NUM> may then be secured or otherwise fit in the distal annular groove <NUM> of the master link pin <NUM>. In a preferred embodiment, the master retaining ring <NUM> is wrapped three times around the maser link pin <NUM> until the master retaining ring <NUM> is secured in the distal annular groove <NUM>. The master link pin <NUM> may then be secured in the master link box <NUM> and the master link pin <NUM> may rotate within the master link bushing <NUM>, the pin bores <NUM> of the master links <NUM>, <NUM>, and the link seal bores <NUM> of the track links <NUM>, <NUM>.

The master link pin <NUM> may be inserted into the master link box <NUM> from either side. For example, the master link pin <NUM> may be inserted first through the left-hand master link <NUM>, then through the master link bushing <NUM>, and subsequently through the right-hand master link <NUM> (<FIG>) or the master link pin <NUM> may be inserted through the right-hand master link <NUM>, then through the master link bushing <NUM>, and subsequently through the left-hand master link <NUM> (<FIG>). When inserted from either direction, the distal annular groove <NUM> will be disposed on the distal side of the lateral annular recess <NUM> of the master link <NUM>, <NUM> through which the distal end <NUM> of the master link pin <NUM> was inserted second, and the master retaining ring <NUM> may be secured or otherwise retained in the distal annular groove <NUM> of the master link pin <NUM>. As such, the master link pin <NUM> may be inserted into the master link box <NUM> from either direction and then secured in the master link box <NUM> by the master retaining ring <NUM>, thereby allowing a user to join the master link box <NUM> to the front and rear ends <NUM>, <NUM> of the link assembly <NUM>. In such a manner, the continuous track <NUM> may be secured on the work machine <NUM> from either the outside of the work machine <NUM> or inside of the work machine <NUM> for either the left or right continuous track <NUM>.

The disclosed master link box <NUM> may be integrated with tracks <NUM> of many work machines <NUM> where durability of the track <NUM> is required including, but not limited to, a track-type tractor, a half-track machine, an excavator, a tank, some other type of mobile machine, or even a stationary machine such as a conveyor. By incorporating the disclosed master link box <NUM> of the present disclosure, the durability of the continuous tracks <NUM> may be improved and the continuous tracks <NUM> may be repaired or replaced less frequently. Further, when the master link box <NUM> is included at the front and rear ends <NUM>, <NUM> of a link assembly <NUM>, the ends <NUM>, <NUM> of the link assembly <NUM> may be joined together to form a continuous track <NUM> without the use of a hydraulic press or other complicated and/or relatively immovable tool. Moreover, where the master link box <NUM> is employed, the continuous track <NUM> may be secured around the rotatable elements <NUM>, <NUM>, <NUM>, <NUM> of the work machine <NUM> from either the outside or inside of work machine <NUM> for either the left or right continuous track <NUM>.

The master link box <NUM> includes first and second master links <NUM>, <NUM> having pin bores <NUM> and lateral annular recesses <NUM>, a master link bushing <NUM>, and a master link pin <NUM> having a distal annular groove <NUM> disposed near the distal end <NUM> and a radial projection <NUM> disposed near the proximal end <NUM>. When the master link pin <NUM> is inserted into the master link box <NUM> through the pin bore <NUM> of one of the master links <NUM>, <NUM>, through the master link bushing <NUM>, and through the pin bore <NUM> of the other master link <NUM>, <NUM>, the projection surface <NUM> of the radial projection <NUM> of the master link pin <NUM> will abut the lateral annular recess <NUM> of the master link <NUM>, <NUM> through which the master link pin <NUM> was first inserted when the master link pin <NUM> is in the proper position and will thereby prevent the master link pin <NUM> from being inserted too far through the pin bores <NUM>. The master link pin <NUM> may be easily aligned with and inserted into the master link box <NUM> without the use of expensive and/or relatively immovable alignment or fitting tools. The master link pin <NUM> does not need to be re-adjusted afterward.

The master link box <NUM> also includes a master retaining ring <NUM> which securely fits in the distal annular groove <NUM> of the master link pin <NUM> and is larger than the pin bores <NUM> of the master links <NUM>, <NUM>. When the master link pin <NUM> is fully inserted in the master link box <NUM> and the master retaining ring <NUM> is secured in the distal annular groove <NUM>, the master link pin <NUM> is secured in the master link box <NUM> and will not retract out of the master link box <NUM>. The master retaining ring <NUM> may be a triple wrap retaining ring which is wrapped three times around the master link pin <NUM> in the distal annular groove <NUM>. As such, the master retaining ring <NUM> may easily be secured in the distal annular groove <NUM> without the use of expensive and/or otherwise immovable fitting tools and the master retaining ring <NUM> may be secured on the master link pin <NUM> without re-positioning the master link pin <NUM> in the master link box <NUM>.

The master link pin <NUM> may join the master links <NUM>, <NUM> to the bushing <NUM> disposed between two track links <NUM>, <NUM>, such that the master link box <NUM> connects the front and rear ends <NUM>, <NUM> of the link assembly <NUM> to form the continuous track <NUM>. The master link pin <NUM> is secured in the master link box <NUM> via the abutment between the radial projection <NUM> of the master link pin <NUM> and the lateral annular recess <NUM> of one of the master links <NUM>, <NUM> and the abutment between the master retaining ring <NUM> and the lateral annular recess <NUM> of the other master link <NUM>, <NUM>. As such, the master link pin <NUM> is not rotationally fixed within either of the pin bores <NUM> of the master links <NUM>, <NUM> or the master link bushing <NUM>. Accordingly, as the continuous track <NUM> rotates around the rotatable elements <NUM>, <NUM>, <NUM>, <NUM> of the work machine <NUM>, the track links <NUM>, <NUM> and master links <NUM>, <NUM> may pivot about the master link pin <NUM>, resulting in a smoother ride for the work machine <NUM>.

Because the master link pin <NUM> may be inserted first through the either the left-hand or right-hand master link <NUM>, <NUM>, through the remainder of the master link box <NUM>, and then secured by the master retaining ring <NUM>, the master link box <NUM> may be assembled from either the outside or inside of the track <NUM>. This ability to assemble the master link box <NUM> from either side of the track <NUM> makes the assembly of the link assembly <NUM> into the continuous track <NUM> easier, particularly as assembly or reassembly of the track <NUM> in the field may be required with the master link box <NUM> at various positions on the track <NUM>.

In view of the many possible embodiments to which the principles of the disclosure can be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope of the disclosure. Rather the scope of the disclosure is defined by the following claims.

It will be appreciated that the foregoing description provides examples of the disclosed apparatus and system. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.

Claim 1:
A master link box (<NUM>) for use in a continuous track (<NUM>) of a work machine (<NUM>), the master link box (<NUM>) comprising:
a left-hand master link (<NUM>) having a first distal surface (<NUM>), a first proximal surface (<NUM>) opposite the first distal surface (<NUM>), a first pin bore (<NUM>) extending between the first distal surface (<NUM>) and the first proximal surface (<NUM>), a first link seal bore (<NUM>), and a first lateral annular recess (<NUM>) disposed around the first pin bore (<NUM>) and inset from the first distal surface (<NUM>);
a right-hand master (<NUM>) having a second distal surface (<NUM>), a second proximal surface (<NUM>) opposite the second distal surface (<NUM>), a second pin bore (<NUM>) extending between the second distal surface (<NUM>) and the second proximal surface (<NUM>), a second link seal bore (<NUM>), and a second lateral annular recess (<NUM>) disposed around the second pin bore (<NUM>) and inset from the second distal surface (<NUM>);
a master link pin (<NUM>) receivable in the first pin bore (<NUM>) and the second pin bore (<NUM>), the master link pin (<NUM>) comprising:
a distal end (<NUM>);
a proximal end (<NUM>) opposite the distal end (<NUM>);
an outer circumferential surface (<NUM>);
a distal annular groove (<NUM>) in the outer circumferential surface (<NUM>) near the distal end (<NUM>); and
a radial projection (<NUM>) near the proximal end (<NUM>) having a projection surface (<NUM>) extending outwardly from the outer circumferential surface (<NUM>); and
a master retaining ring (<NUM>) disposed in the distal annular groove (<NUM>);
characterised in that
to assemble the master link box (<NUM>), the master link pin (<NUM>) is configured to be first inserted through either the left-hand master link (<NUM>) or the right-hand master link (<NUM>) and subsequently secured in place by the master retaining ring (<NUM>);
wherein the projection surface (<NUM>) is configured to abut one of the first lateral annular recess (<NUM>) and the second lateral annular recess when the master link box (<NUM>) is assembled.