The present invention relates to track chains for track laying work machine, and more particularly to an articulated pin joint of such a track chain.
In operation, track laying work machines are subject to some of the most severe operating environments. In particular, the track chain assemblies of such work machines operate in continuous contact with abrasive, and occasionally corrosive, soil environments. Such track assemblies include pin and bushing joints positioned between adjacent pairs of track links to hingably couple the pairs of links. Each pair of links, in turn, carry ground-engaging track shoes. The pin and bushing joints are subject to extreme wear from the abrasive and corrosive soil environment and incur high stresses through the support of the track laying work machine and the engagement with drive sprockets.
Attempts have been made to increase service life of such track assemblies by improved metallurgy, factory sealing, lubrication of the joints, and by providing factory-assembled joints in serviceable form. Examples of such designs are disclosed in U.S. Pat. No. 3,958,836 issued to Brown on May 25, 1976 and U.S. Pat. No. 3,762,778 issued to Boggs et al on Oct. 2, 1973 that have proved effective in obtaining increased component life.
The arrangement disclosed in Brown, however, has a high production cost due to drilling a hole through the pin, tapping both ends, plugging one end and counter boring the opposite end and then placing a fitting in the counter bore. The counter bore is an attempt to protect the fitting by placing the fitting deeper within the pin. However, this arrangement allows material to collect in the void around the fitting and erode the fitting. At a minimum the material build up will compact and harden, which will require cleaning before replacement lubricant can be injected into the pin.
Boggs, on the other hand, discloses a much more efficient design that uses an elastomeric stopper placed in one end of a track pin. The stopper has a through hole in which oil is injected and an additional plug that is positioned in the through hole of the stopper to retain the fluid. However, this design requires the track to be removed from the machine and placed on its side to effectively fill the hollow pin with oil. Excess air is then allowed to escape through a passage in the stopper. A second stopper is then positioned in the passage to retain the oil.
The present invention is directed to overcome one or more of the problems as set forth above.
In one aspect of the present invention an articulated pin joint is provided for a track chain. The articulated pin joint includes a track pin defining a longitudinal axis and having an outer surface. A central cavity is positioned within the track pin. A cross bore extends from the outer surface to the central cavity. A bushing having an inner surface disposed about the outer surface of the track pin. A plug is positioned within the central cavity of the pin and has an axial passage extending therethrough.
Referring to the drawings and in particular
Track pin 16 includes a central cavity 20 concentrically positioned about a longitudinal axis 22. A bore 24 extends a predetermined distance through the track pin 16 to define a closed-end portion 26 at one end and an open-end portion 28 at the other end to form the central cavity 20. Central cavity 20 contains a supply of lubricant, which in this example is preferably grease. It should be understood that any of a number of alternate configurations of the track pin 16 are contemplated for defining the central cavity 20. For example, the track pin 16 may have a bore that runs the entire axial length of the track pin 16, or have a bore extending from each end with a closed portion centrally located to define a cavity at each end of the track pin 16 without departing from the gist of the present invention.
At least one cross bore 30 extends from an outer surface 32 of the track pin 16 to the central cavity 20. Cross bore 30 is positioned so that a supply of grease is fed in any suitable manner to lubricate the outer surface 32 of the track pin 16 and an inner surface 34 of the bushing 18. A pair of suitable seals 36 are normally provided in the vicinity of each end of the bushing 18 to minimize loss of grease and to prevent entry of foreign matter.
Now referring to
As shown in
During assembly of the track chain 10 the bushings 18 are positioned about the track pins 16 with adjacent pairs of links 14 pressed onto the pins 16 or other members in a known manner. The track shoes (not shown) are fastened to each pair of adjacent links 14. The free ends of the track chain 10 are then attached together by master links (not shown) in the usual known manner.
The track pins 16 may have the plugs 40 pre-positioned in the open-end portion 28 or inserted after the track chain 10 is fully assembled. The diameter or shape of the plug 40 is configured so as not only to retain the plug within the open-end portion 28 but to also close off the axial passage 42 in the plug 40 by compressive force. The grease injection tool 43 is inserted into the axial passage 42 of the plug 40 and fills the central cavity 20 with grease. The cross bore 30 allows grease to flow to the outer surface 32 of the track pin 16 and the inner surface of the bushing 18 and the seals 36. When enough grease has been injected into the central cavity 20 the needle is withdrawn from the axial passage 42. Axial passage 42 then closes with a force sufficient to retain the grease within the central cavity 20 as well as keeping foreign material from entering through the axial passage 42. This step can be repeated in the field without having to remove the track chain 10.
In the alternative arrangement shown in
It should be clearly understood that the present articulated pin joint 19 allows for lubricant to be injected in the central cavity 20 of the track pin 16 at a job site during routine maintenance operations. Therfore, lubricant may be re-injected at numerous intervals without removing the machine from the job site or removal of the track chain 10 thereby saving time and money.
Number | Name | Date | Kind |
---|---|---|---|
3762778 | Boggs et al. | Oct 1973 | A |
3829173 | Stedman | Aug 1974 | A |
3831240 | Boggs et al. | Aug 1974 | A |
3924904 | Wagner et al. | Dec 1975 | A |
3958836 | Brown et al. | May 1976 | A |
3963047 | Moring | Jun 1976 | A |
3987706 | Corrigan | Oct 1976 | A |
4030178 | Luebkemann | Jun 1977 | A |
4067414 | Funke | Jan 1978 | A |
4120537 | Roley et al. | Oct 1978 | A |
4146053 | Corrigan | Mar 1979 | A |
4191431 | Roley et al. | Mar 1980 | A |
4251182 | Schroeder | Feb 1981 | A |
4398862 | Schroeder | Aug 1983 | A |
4438981 | Harms | Mar 1984 | A |
4456041 | Grilli et al. | Jun 1984 | A |
4575914 | Armida et al. | Mar 1986 | A |
4582366 | Burfield et al. | Apr 1986 | A |
5044812 | Ardelt et al. | Sep 1991 | A |
5069509 | Johnson et al. | Dec 1991 | A |
5165765 | Baylor | Nov 1992 | A |
5207293 | Eden et al. | May 1993 | A |
5829850 | Ketting et al. | Nov 1998 | A |
5921419 | Niedospial, Jr. et al. | Jul 1999 | A |
6042295 | Barden | Mar 2000 | A |
6079519 | Lottes | Jun 2000 | A |
Number | Date | Country |
---|---|---|
43354 | Jan 1982 | EP |
2288376 | Oct 1995 | GB |
Number | Date | Country | |
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20040114993 A1 | Jun 2004 | US |