Railway draft appliances – Cushioned
Reexamination Certificate
2000-02-24
2001-11-27
Morano, S. Joseph (Department: 3617)
Railway draft appliances
Cushioned
C213S04000D, C213S04000D, C213S064000
Reexamination Certificate
active
06321922
ABSTRACT:
FIELD OF INVENTION
The present invention relates, in general, to vehicular type couplers and, more particularly, this invention relates to robust, flexible type vehicular couplers that provide a substantially equalized shear bolt load and preload under conditions of unequal coupling forces.
BACKGROUND OF THE INVENTION
As is generally well recognized in the railway coupling art, light rail vehicle (LRV) couplers make use of emergency release bolts. These emergency release bolts extend radially through a draft gear tube and into a hollow shank member located behind and extending rearwardly from a coupling head. Such hollow shank member contains an energy absorbing and dissipation means. There is a coupling head disposed on a first LRV car that engages and mechanically couples to a coupling head disposed on a second LRV car. The draft gear tube disposed on each respective car is mechanically secured to the underside of its associated car.
Existing couplers normally employ a rigid hollow coupling head shank portion suspended in a draft gear tube by radially extending shear bolts. These shear bolts are designed to shear and break in two when the coupling forces between two cars which are coupled together exceeds a predetermined coupling load limit, as provided by the strength of the shear bolts.
Normally, the coupling forces that occur when a train of LRV cars is being assembled and connected together for travel with a locomotive, or lead car, exert less load on such shear bolts than the predetermined limit so that the coupling shank/draft gear tube assembly remains intact.
In contrast thereto, hard couplings or collisions between cars will exert loads in excess of the predetermined limit. When this excess load occurs the bolts shear. This allows the coupler shank portion to slide into the draft gear tube and engage and compress the energy dissipation means located in the draft gear tube. As is known in the art, such compression of the energy dissipation means helps to absorb the energy of the collision between the cars by deformation work.
In such existing couplers, the outside diameter of the coupler shank portion is less than the inside diameter of the draft gear tube in order to allow assembly of the two components and travel of such coupler shank portion into the draft gear tube during the above described collision couplings. As such, the shear bolts effect suspension of the coupler shank portion in the draft gear tube. The coupler shank portion and an integral collar do not contact the inside surface of the draft gear tube.
The shear bolts provide all the support for the coupler shank portion and are unevenly loaded when the coupler heads of two LRV cars do not contact each other squarely. An angled contact of the face portions of the coupler heads tend to place the majority of the contacting load on one side of the coupler shank portion and on those shear bolts located on that side. This occurrence can cause such shear bolts to shear prematurely and fatigue more rapidly during normal car couplings.
The above and following description is directed to light rail vehicle (LRV) type coupling, although it is believed the principles of the present invention would be useful in coupling other types of vehicles, particularly, passenger transit type railway vehicles.
BRIEF SUMMARY OF THE INVENTION
The present invention solves the above described problem of uneven coupling forces by providing a coupler tube shank portion with longitudinal slots. Such longitudinal slots permit the wall of the coupler tube shank portion to expand outwardly and engage the inside surface of the draft gear tube when radially extending shear bolts are threaded into the shank wall. This arrangement will place the shear bolts in a virtually pure shear configuration, while engagement of the shank and draft gear walls help to equalize the loads during an angled coupling to provide a more consistent emergency release operation.
In addition, consistent emergency release shear bolt operation is further enhanced by equalizing the torque applied to the shear bolts when they are tightened in the process of assembling the coupler shank portion and draft gear tube components.
OBJECTS OF THE INVENTION
It is, therefore, one of the primary objects of the present invention to provide an improved shock resistant coupler which will substantially equalize uneven coupling forces on shear bolts when vehicles are mechanically coupled together.
Another object of the present invention is to provide an improved shock resistant coupler in which such equalization is achieved in a relatively low cost manner by simply longitudinally slotting the tube of the coupler shank portion to allow the walls of such tube to expand and engage the inside surface of the draft gear tube.
Still another object of the present invention is to provide an improved shock resistant coupler in which such equalization can be enhanced by providing longitudinal relief grooves in a collar that is located at the end of the coupler head shank.
A further object of the present invention is to provide an improved shock resistant coupler in which such slots and grooves can be machined in the shank and collar portions or they can be formed during casting of the shank and collar portions.
Yet another object of the present invention is to provide an improved shock resistant coupler that will equally preload the release bolts when the coupler shank and draft gear tube portions are assembled.
In addition to the various objects and advantages of the present invention that have been discussed in some specific detail above, various other objects and advantages of the invention will become more readily apparent to those persons who are skilled in the relevant art from the following more detailed description of the invention, particularly, when such description is taken in conjunction with the attached drawing Figures and with the appended claims.
REFERENCES:
patent: 1165190 (1915-12-01), McCord
patent: 3118692 (1964-01-01), Fitzhugh
patent: 3968982 (1976-07-01), Belicic
patent: 4017139 (1977-04-01), Nelson
patent: 4178023 (1979-12-01), Guest
Kovacs Zoltan
Preuninger David S.
Rumsey Steven C.
James Ray & Associates
Jules Frantz F.
Morano S. Joseph
Westinghouse Air Brake Company
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