BACKGROUND OF THE INVENTION
This invention relates generally to railway car coupling systems, and more particularly to an improved polymeric knuckle pin.
This invention is applicable to any type of coupler that uses a pin to pivotally secure the coupler and knuckle together. The knuckle pin pivotally connects a coupler and a knuckle on a railway car. Such railway knuckle pins are usually comprised of a metal or plastic material.
Knuckle pins are shown in U.S. Pat. Nos. 5,145,076, 5,630,519, and 5,736,088. Prior known knuckle pins were made of either metal or plastic material. Metal pins are heavy, limiting the number of pins a maintenance worker can carry while checking the coupler-knuckle connection on the railroad cars. Metal pins are also very hard to maintain because they are susceptible to rust and corrosion. Furthermore, as a railway car operates, buff and draft movements cause the coupler-knuckle connection to exert stress, force, and impact on the knuckle pin. The high hardness of a metal pin may cause damage to the coupler or knuckle. The pin may bend and impede coupler-knuckle operation, and in rotator cars, if structurally compromised the pin may drop out and cause damage to the crushers.
Prior known plastic knuckle pins alleviate some of the damages problems caused by the metal knuckle pins, however, the plastic pins were susceptible to defects caused during the formation process. It was not uncommon for plastic pins to contain air and moisture pockets, making the pins non-uniform in their material matrix. Other plastic pins contained spaced-apart annular relief areas in the shaft to improve the overall uniformity of the plastic material. However, these relief areas significantly compromise the structural integrity of the pin and create multiple stress concentration points causing the plastic pins to break easier.
The present invention provides an improved, impact and stress absorbing knuckle pin that reduces fatigue in the coupler, knuckle, and knuckle pin.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved railway car polymeric knuckle pin is provided for use in a railway car coupler assembly.
The polymeric knuckle pin is comprised of a shaft, a head on one end of the shaft, and a locking mechanism on the end of the shaft opposite the head to secure the pin in position as a pivot point between a coupler and a knuckle connection on a railway car. The knuckle pin contains at least one groove in the shaft. The grove is strategically placed in an area on the shaft of the pin where the coupler-knuckle connection exerts impact, force, and stress on the pin. A single or plurality of elastomer rings is placed in the groove or grooves on the shaft. The elastomer rings in the groove provide cushion to the pin from the impact, force, and stress, allow the pin to avoid hard contact with the coupler and knuckle, distribute the loads exerted by the coupler and knuckle more evenly, realign the coupler and knuckle positions, and protect the pin itself from surface cuts and scratches. The elastomer rings on the shaft of the pin improve the life of both the coupler-knuckle assembly and the pin.
In another embodiment of the present invention, a polymeric knuckle pin is comprised of a shaft, a head on one end of the shaft, and a locking mechanism on the other end of the shaft opposite the head. The shaft containing at least one groove at a point where the coupler-knuckle connection exerts force on the shaft of the pin. The groove or grooves contain a single elastomer ring or plurality of elastomer rings. The head of the pin is non-round shape. The shaft contains a center area between the head and the locking mechanism where the diameter of the shaft is smaller than the diameter of the rest of the shaft.
It is an object of the present invention to provide a knuckle pin with elastomer rings that prevent the pin from permanent bending and other damages.
It is also an object of the present invention to provide a pin with elastomer rings that have a high elasticity and will fully recover to their original position once stress from the coupler-knuckle connection is removed from the pin.
It is a further object of the present invention to provide a knuckle pin with elastomer rings that will realign the coupler-knuckle assembly.
It is a further object of the present invention to provide a knuckle pin with elastomer rings that will reduce damage and fatigue on the coupler-knuckle assembly.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top perspective view of a coupler-knuckle assembly with the improved knuckle pin of the present invention in place;
FIG. 2 is a front elevational view of the improved knuckle pin of the present invention;
FIG. 3 is a side elevational view of the improved knuckle pin of the present invention;
FIG. 4 is a top plan view of the improved knuckle pin of the present invention;
FIG. 5 is a bottom plan view of the improved knuckle pin of the present invention;
FIG. 6 is side perspective view of a second embodiment of the improved knuckle pin of the present invention; and
FIG. 7 is a sectional view of the coupler-knuckle assembly along lines 7-7 of FIG. 1.
DETAILED DESCRIPTION
Referring now to FIG. 1, a coupler-knuckle assembly incorporating preferred embodiment the present invention is generally designated 10 and includes a coupler body 12, a knuckle 14, and a knuckle pin 16. In the present assembly, the knuckle 14 is pivotally connected to the coupler body 12 by the knuckle pin 16. The coupler body 12, as shown, has its knuckle 14 in the closed position.
Referring now to FIG. 2, the knuckle pin of the present invention generally indicated 16, includes a shaft 32 with a center region 33, a top end 35, and a bottom end 42. A knuckle-pin head 30 is on the top end 35 of the shaft 32, and a snap lock locking mechanism 36 is on the bottom end 42 of the shaft 32. The knuckle pin of the present invention is preferably a solid piece of molded urethane or polyurethane as described below. In comparison to a metallic knuckle pin, the polymeric pin is lighter and more resilient, accepts bending fatigue better, and creates less friction as a pivot point between the coupler and knuckle improving performance of the coupler-knuckle assembly.
The knuckle pin head 30 of the pin 16 has a dome-shaped top 31, which is sized diametrically larger than the shaft 32. The pin head 30 also has a significantly larger diameter than the pinhole in the coupler-knuckle assembly. An annular radius 34 is formed between the top end of the shaft 35 and the pin head 30 to protect against damage to the pin when installing the pin.
At the bottom end 42 of the shaft 32, the locking mechanism 36 is comprised of two snap lock tabs 37 and 39. The snap lock tabs 37 and 39 are compressed together or towards each other as the pin is inserted into the coupler-knuckle assembly 10 and expand when the pin is fully inserted into the coupler-knuckle assembly. The snap lock tabs 37 and 39 secure the knuckle pin in the coupler-knuckle assembly, because once the pin is fully inserted into the assembly, the snap lock tabs expand or snap-out to greater diameter than the pinhole in the coupler body. A cotter pin or other suitable locking mechanisms can also be used.
The shaft 32 is generally cylindrical in shape and includes at least one indented area, wherein the indented area is diametrically smaller than the shaft 32. An upper indented area 38 and a lower indented area 38B are located on the shaft 32 in the coupler-knuckle impact regions 112 and 113 (shown in FIG. 7), but the groove can extend beyond the coupler-knuckle impact regions 112 and 113. Preferably there are multiple indented areas on shaft 32. One indented area 38 is located on shaft 32 where the shaft 32 contacts the coupler body 12 and knuckle 14 in the coupler-knuckle top impact region 112, and the other indented area 38B is located on the shaft 32 where the shaft 32 contacts the coupler body 12 and knuckle 14 in the coupler-knuckle bottom impact region 113. Elastomer rings 40 are located on the shaft 32 covering and filling some or all of the indented areas. In the areas of the shaft 32 where the indented areas and the elastomer rings 40 are located, the diameter of the indented area plus the rings 40 are the same as the diameter of the shaft 32 or slightly larger than the diameter of the shaft. The elastomer rings of the present invention are preferably made from thermal plastic polyurethane material, but the rings can be made from any material having a high elasticity and resiliency. The number of elastomer rings varies depending on the length of the indented area and the diameter of the rings, but preferably a plurality of elastomer rings are placed inside each indented area. Placement of the elastomer rings in the indented areas along the area where the coupler-knuckle connection exerts the greatest stress, force, and impact on the knuckle pin allows fatigue on both the coupler-knuckle assembly and the pin to be reduced. The elastomer rings deform elastically absorbing the force and stress from the coupler-knuckle connection and cushion any impact that occurs.
Referring now to FIG. 3, the improved knuckle pin 16 is shown in a side elevational view. The knuckle pin 16 is completely symmetrical except for the locking mechanism 36 on the bottom end 42 of the shaft 32. The two snap lock tabs 37 and 39 are only on two sides of the knuckle pin 16. Everything else shown is the same as previously described in FIG. 2.
Referring now to FIG. 4, a top plan view shows that in the preferred embodiment of the present invention, the knuckle pin head 30 is circular in shape. As shown, the elastomer rings 40 extend radially outward, slightly beyond the diameter of the shaft 32.
Referring now to FIG. 5, a bottom plan view of the knuckle pin 16 shows that the pin is completely symmetrical except for the snap lock tabs 37 and 39 on the bottom end 42 of the shaft 32.
Referring now to FIG. 6, another embodiment of the knuckle pin of the present invention is shown at 60, including a shaft 66, wherein the shaft 66 has a top end 67, a center region 68, and a bottom end 69, a knuckle-pin head 62 on the top end 67 of the shaft 66, and a locking mechanism 76 on the bottom end 69 of the shaft 66. The indented area 72 and elastomer ring 74 structure is the same as described in FIG. 2. In the present embodiment, the knuckle pin head 62 is a non-round shape 64 preventing rotation of the knuckle pin 60 while inserted in the coupler-knuckle assembly 10. The knuckle pin head 62 as shown has one flat side with the remaining sides round, but any other non-round shapes are contemplated in this invention. The shaft 66 has a reduction in the shaft diameter 70 in the center region 68 of the shaft 66. Typically during use, very little stress is paced on the center region 68 of the shaft 66. The reduction in shaft diameter 70 allows the knuckle pin 60 to be lighter because less material is used, while also facilitating the cooling process by allowing the pin to cool faster and more evenly, ensuring the pin has a uniform material matrix after the molding process. The bottom end of the shaft 69 has a bottom extension 78 with a hole 80. This a non-standard element on most knuckle pins, but it allows a compressed air hose to be tied to the shaft through the hole 80.
Referring now to FIG. 7, a sectional view including the knuckle pin 16 of the present invention locked into place in a coupler-knuckle assembly 10 is shown. The knuckle pin 16 is inserted into the coupler pinhole 114 that is aligned with the knuckle pinhole 116 until the locking mechanism 76 engages and prevents the pin from coming loose or falling out of the coupler-knuckle assembly 10. When the knuckle pin 16 is fully inserted into the coupler knuckle assembly 10, as shown in FIG. 7, the indented area 72 containing the elastomer rings 74 are aligned with the coupler-knuckle impact regions 112. There is a top coupler-knuckle impact region 112 and a bottom coupler-knuckle impact region 113 where the coupler and knuckle components meet. The coupler-knuckle impact regions 112 are where the coupler-knuckle assembly 10 exerts the greatest amount of force, impact, and stress on the knuckle pin 16. The force and stress exerted on the knuckle pin 16 are caused by the misalignment of the knuckle pulling lugs 100 and the coupler body pulling lugs 106. The knuckle has two upper pulling lugs 101 and 102, and two lower pulling lugs 103 and 104. The coupler body has two upper pulling lugs 107 and 108, and two lower pulling lugs 109 and 110. While in use, when uneven force is exerted on the upper and lower pulling lugs of the coupler and knuckle, the coupler knuckle assembly can become misaligned placing force, stress, and impact on the knuckle pin 16. The elastomer rings 74 deform elastically absorbing the force, impact, and stress exerted on the knuckle pin 16 reducing the fatigue of the pin, and the resiliency of the elastomer rings realign the coupler 12 and knuckle 14. Once the coupler 12 and the knuckle 14 are realigned in their original and proper position, and the outside stress is removed from the knuckle pin 16, the elastomer rings 74 fully recover to their original position.
While particular embodiments of the present knuckle pin have been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects.
Patent Application
20140110368
