Railway switches and signals – Switch stands
Reexamination Certificate
1999-04-20
2001-10-02
Morano, S. Joseph (Department: 3617)
Railway switches and signals
Switch stands
C246S358000, C246S382000, C464S030000
Reexamination Certificate
active
06296209
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to railroad switch stands for moving a pair of switch points between two rails to divert rolling stock from one track to another. More particularly, this invention relates to improved railroad switch stands that have adjustable linkages, that can isolate damages when there is a run through and that provide a visual indication when the switch stand has suffered damage.
DESCRIPTION OF THE PRIOR ART
In switching rolling stock from one set of rails to another, a pair of stationary rails and a pair of switching rails are arranged so that the switching rails can be moved either to keep trains on a main track or divert them to a branch track. The switching rails are moved by a switching device which includes a connecting rod that extends horizontally beneath the tracks to points of connection with the switching rails.
A switching device typically includes a switch stand at one side of the rails which can be operated either manually or automatically. The switch stands of the type with which this invention is concerned are sometimes referred to as the “Model 51 New Century” which have been in use since the early 1900's with little modification. When operated by hand, a weighted lever arm lying horizontally on the ground or at the base of the switch stand can be lifted and thrown through an arc of 180° to the opposite side of the switch stand where it again will rest horizontally on the ground or base. It is common practice to mount a pinion gear at the pivot end of the lever arm which, through a mating segment gear arrangement in the switch stand rotates a vertically disposed spindle. A horizontally disposed crank is secured to the lower end of the spindle. The end of the crank that is remote from the axis of the spindle carries an end fixture adapted to engage the connecting rod. By these means, rotation of the spindle, acting through the crank, imparts a reciprocating movement to the connecting rod which, in turn, positions the switch points. One of the early designs of a switch stand of this general type is disclosed in U.S. Pat. No. 401,671 issued to Alkins in 1889.
This basic switch stand, as modified over the years, is still in common use today despite several disadvantages and failings. As discussed above, a crank is utilized to link the movement of the spindle to the connecting rod. Each crank has a radius arm defined by the distance between the axis of the spindle and the attachment point to the connecting rod. As the length of the radius arm may vary somewhat from one installation to another, a number of cranks with different radius arms are kept in inventory to accommodate the requirements of a given switch stand assembly.
Another weakness in the design of switch stands is that they may suffer anywhere from a major damage to total destruction caused by a run through—that is, when a train passes the wrong way through a closed switch.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a switch stand that is protected from major damage if there is a run through.
Another object of this invention is to provide a switch stand that can be easily repaired and rapidly put back in service after it has been damaged as in a run through.
A further object of the invention is to design a switch stand that will provide a visual indication that the switch stand has been damaged and needs repair even though the switch stand appears to be working properly.
REFERENCES:
patent: 296808 (1884-04-01), Witty
patent: 452543 (1891-05-01), Gibson
patent: 534761 (1895-02-01), Rowlands
patent: 1272235 (1918-07-01), Dostie
patent: 2409385 (1946-10-01), Pletcher
patent: 4938438 (1990-07-01), Farrell et al.
patent: 5495660 (1996-03-01), Choi
patent: 14103 (1879-11-01), None
patent: 1382106 (1964-11-01), None
Church Richard O.
Jules Frantz F.
Morano S. Joseph
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