Abstract:
A cartridge assembly is provided that connects first and second links of a track chain of a track type work machine. The cartridge assembly includes first and second collars and a track pin. The first collar is positioned within a first hole of the first link and the second collar is positioned within a second hole of the second link. The first collar is fixed in relation to the first link and the track pin and the second collar is fixed in relation to the second link and is allowed to move relative to the track pin.

Description:
TECHNICAL FIELD 
     This invention relates generally to track type work machines, and more particularly to a cartridge assembly for a track chain of a track type work machine. 
     BACKGROUND 
     The track chain of track type work machines generally include a pair of parallel chains, with each parallel chain being made up of a series of entrained track links. The entrained track links cooperate to form a number of track joints which allow the necessary relative movement between adjacent links. For example, adjacent links must move relative to one another when the track chain rotates about a sprocket of the track type work machine. 
     The track joints are typically equipped with a track seal assembly to keep out various corrosive and abrasive mixtures of water, dirt, sand, rock or other mineral or chemical elements to which the track chain is exposed during its use. The track seal assembly also functions to keep a lubricant within the track joint to facilitate the aforementioned relative movement of the track links. 
     One prior art track seal assembly design used to accomplish the aforementioned functions employs a track link having a groove defined therein. A sealing member is positioned within the groove and then the sealing member is axially urged into sliding sealing engagement against a polished bearing surface by a resilient rubber load ring. However, a number of problems have been encountered using the above described arrangement. 
     One such problem relates to grooving of the bearing surface. The mixtures of various abrasive particles found in the working environment of a track chain tend to make excellent grinding compounds which can wear grooves into the bearing surface. If these grooves become sufficiently deep, the integrity of the track seal assembly can be compromised and abrasive particles can enter the track joint. These grooves also provide a path for lubricants contained within the track joint to leak out. All of the above discussed problems can result in the failure of the track joint and thus the track chain. Once the track chain assembly fails, the various parts thereof must be replaced in a piece part manner and the track chain reassembled. The process of removing the worn parts of the track chain then reassembling the same requires a significant amount of time and thus decreases the productivity of the work machine. 
     The present invention is directed to overcoming one or more of the problems or disadvantages associated with the prior art. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention, there is provided a cartridge assembly for a track chain. The cartridge assembly includes (i) a track pin having a longitudinal axis, (ii) a first collar having a first bore defined therethrough, the first collar being positioned relative to the track pin such that a first portion of the track pin is disposed within the first bore, (iii) a second collar having a second bore defined therethrough, the second collar being positioned relative to the track pin such that a second portion of the track pin is disposed within the second bore, (iv) a first track link having a first hole defined therein, the first track link being positioned relative to the first collar such that the first collar is disposed within the first hole of the first track link, and (v) a second track link having a second hole defined therein, the second track link being positioned relative to the second collar such that the second collar is disposed within the second hole of the second track link. The first collar is fixed in relation to the track pin such that first collar is unable to rotate relative to the track pin. The first track link is fixed in relation to the first collar such that the first track link is unable to rotate relative to the first collar. The second collar is able to rotate relative to the track pin around the longitudinal axis. The second track link is fixed in relation to the second collar such that the second track link is unable to rotate relative to the second collar. 
     In accordance with another embodiment of the present invention, there is provided an undercarriage assembly for a track type work machine. The undercarriage assembly includes a frame and an idler wheel operatively coupled to the frame. The undercarriage assembly also includes a track chain operatively coupled to the frame and the idler wheel. The track chain includes a cartridge assembly having (i) track pin having a longitudinal axis, (ii) a first collar having a first bore defined therethrough, the first collar being positioned relative to the track pin such that a first portion of the track pin is disposed within the first bore, (iii) a second collar having a second bore defined therethrough, the second collar being positioned relative to the track pin such that a second portion of the track pin is disposed within the second bore, (iv) a first track link having a first hole defined therein, the first track link being positioned relative to the first collar such that the first collar is disposed within the first hole of the first track link, (v) a second track link having a second hole defined therein, the second track link being positioned relative to the second collar such that the second collar is disposed within the second hole of the second track link, (vi) the first collar fixed in relation to the track pin such that first collar is unable to rotate relative to the track pin, (vii) the first track link fixed in relation to the first collar such that the first track link is unable to rotate relative to the first collar, (viii) the second collar able to rotate relative to the track pin around the longitudinal axis, and (ix) the second track link fixed in relation to the second collar such that the second track link is unable to rotate relative to the second collar. 
     In accordance with yet another embodiment of the present invention, there is provided a work machine. The work machine includes a frame and an undercarriage assembly operatively coupled to the frame. The undercarriage assembly includes a track chain having a cartridge assembly. The cartridge assembly has (A) a track pin having a longitudinal axis, (B) a first collar having a first bore defined therethrough, the first collar being positioned relative to the track pin such that a first portion of the track pin is disposed within the first bore, (C) a second collar having a second bore defined therethrough, the second collar being positioned relative to the track pin such that a second portion of the track pin is disposed within the second bore, (D) a first track link having a first hole defined therein, the first track link being positioned relative to the first collar such that the first collar is disposed within the first hole of the first track link, (E) a second track link having a second hole defined therein, the second track link being positioned relative to the second collar such that the second collar is disposed within the second hole of the second track link, (F) the first collar fixed in relation to the track pin such that the first collar is unable to rotate relative to the track pin, (G) the first track link fixed in relation to the first collar such that the first track link is unable to rotate relative to the first collar, (H) the second collar able to rotate relative to the track pin around the longitudinal axis, and (I) the second track link fixed in relation to the second collar such that the second link is unable to rotate relative to the second collar. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic representation of a work machine showing a fragmentary perspective view of an undercarriage assembly thereof; 
     FIG. 2 is a fragmentary perspective view of the track chain of the undercarriage assembly of FIG. 1; and 
     FIG. 3 is a perspective cross sectional view of a cartridge assembly of the track chain of FIG. 2 taken along line  3 — 3  of FIG.  2 . 
    
    
     DETAILED DESCRIPTION 
     Referring now to FIGS. 1 and 2 there is shown an exemplary work machine  10  which incorporates the features of the present invention therein. Work machine  10  includes an undercarriage assembly  14  having a frame  12  operatively coupled to the work machine  10 . Undercarriage assembly  14  includes an idler wheel  20  and a track chain  16 . Track chain  16  includes a number of (i) track links  38  and  42 , (ii) cartridge assemblies  18 , and (iii) track shoes  70  and  72 . Track chain  16  also includes a number of drive lugs  46 . 
     Now referring to FIG. 3, cartridge assembly  18  includes a track pin  22  having a longitudinal axis  24 . Track pin  22  also has a lip member  56  which extends outwardly from an exterior surface  58  of track pin  22 . Lip member  56  has a thrust surface  60  defined thereon. Track pin  22  can also have a reservoir  66  and a channel  68  defined therein. Channel  68  is in fluid communication with reservoir  66  and exterior surface  58  of track pin  22  so that a fluid, such as a lubricant, disposed within reservoir  66  is advanced through channel  68  and onto exterior surface  58  during use of cartridge assembly  18 . 
     Cartridge assembly  18  also includes a collar  26  having a bore  28  defined therethrough. Collar  26  is positioned relative to track pin  22  such that a portion  30  of track pin  22  is disposed within bore  28 . Cartridge assembly  18  also includes a collar  32  having a bore  34  defined therethrough. Collar  32  also has a shoulder portion  52  and a shoulder portion  62  defined thereon. Shoulder portion  52  has a thrust portion surface  54  defined thereon. Collar  32  is positioned relative to track pin  22  such that a portion  36  of track pin  22  is disposed within bore  34 . Collar  32  is further positioned relative to track pin  22  so that thrust surface  54  is in contact with thrust surface  60 . 
     Cartridge assembly  18  further includes (i) a cap  64 , (ii) a track link  38 , and (iii) a track link  42 . Note that track links  38  and  42  are substantially identical to each other. Track link  38  has a hole  40  defined therein. Track link  42  has a hole  44  defined therein. Track link  38  is positioned relative to collar  26  such that collar  26  is disposed within hole  40  of track link  38 . Track link  42  is positioned relative to collar  32  such that collar  32  is disposed within hole  44  of track link  42 . Cap  64  is secured to collar  32  (e.g. by welding) so that cap  64  is in contact with shoulder portion  62  of collar  32 . 
     Still referring to FIG. 3, cartridge assembly  18  further includes a seal arrangement  48 . In particular, seal arrangement  48  is positioned in a seal groove  50  defined collar  26  so that seal arrangement  48  contacts collar  26  and collar  32 . 
     It should be understood that collar  26  is fixed in relation to track pin  22  such that collar  26  is unable to rotate relative to track pin  22 . For example, track pin  22  can be press fit into bore  28  of collar  26  so as to substantially prevent relative rotation between these two components. In addition, track link  38  is fixed in relation to collar  26  such that track link  38  is unable to rotate relative to collar  26 . For example, collar  26  can be press fit into hole  40  of track link  38  so as to substantially prevent relative rotation between these two components. 
     On the other hand, collar  32  is able to rotate relative to track pin  22  around longitudinal axis  24 . Track link  42  is fixed in relation to collar  32  such that track link  42  is unable to rotate relative to collar  32 . For example, as described above, collar  32  can be press fit into hole  44  of track link  42  so as to substantially prevent relative rotation between these two components. 
     As shown in FIG. 2, a number of track links  38  and  42  are secured to each other in the above described manner to form a pair of adjacent chains  74  each of which form a closed loop. A track shoe is secured to each track link  38  and  42 . In particular, as shown in FIG. 2, a track shoe  70  is secured to track link  38  by, for example, bolting track shoe  70  to track link  38  via bolt holes  76 . In a similar manner, a track shoe  72  is secured to track link  42  by bolting track shoe  72  to track link  42  via bolt holes  78 . A plate  80  is attached to each track shoe  70  and  72  (e.g. via bolts) so that each plate  80  is interposed adjacent chains  74 . In addition, a drive lug  46  is attached to each plate  80 . 
     It should be understood that the above described track chain  16  forms a closed loop which is positioned around a drive sprocket (not shown) and idler wheel  20  of work machine  10  such that idler wheel  20  is in contact with drive lug  46 . During use of work machine  10  the drive sprocket rotates and engages the track chain  16 , thereby causing the track chain  16  to rotate around a path defined by the drive sprocket and idler wheel  20 . The rotation of track chain  16  causes work machine  10  to be propelled over the ground so as to perform various work functions. 
     Industrial Applicability 
     It should be appreciated that each cartridge assembly  18  has many advantages which facilitate the functioning of track chain  16  and therefore work machine  10 . For example, each cartridge assembly  18  enhances the life of track chain  16  by improving the retention of a lubricant contained within cartridge assembly  18 . Moreover, since each cartridge assembly  18  is self-contained and provides essentially all of the sealing and bearing functions required by track chain  16 , track chain  16  can be easily serviced by removing old worn cartridge assemblies  18  and replacing them with new cartridge assemblies  18 . Removing and replacing the entire cartridge assembly  18  to service track chain  16  is more cost effective and efficient as compared to other track chain designs which require servicing in a piece part manner. 
     Other aspects and features of the present invention can be obtained from a study of the drawings, the disclosures, and the appended claims.