Railway switches and signals – Switch-connected frogs
Reexamination Certificate
2000-03-09
2001-09-11
Morano, S. Joseph (Department: 3617)
Railway switches and signals
Switch-connected frogs
C246S276000, C246S389000
Reexamination Certificate
active
06286791
ABSTRACT:
CROSS-REFERENCES
None.
FIELD OF THE INVENTION
This invention relates generally to railroad trackworks, and particularly concerns an improved trackwork frog assembly of the spring wing rail-type which is principally used at railroad trackwork turn-outs from main line track.
BACKGROUND OF THE INVENTION
A railroad frog is a device which is installed at the intersection of two running rails to permit the flanges of railroad car wheels moving along one of the rails to pass across the other rail. The frog supports the car wheels as they pass over the missing rail tread surface between the throat and the point of the frog, and also provides flangeways for the flanges of those car wheels which pass through the frog.
A railroad spring wing rail frog assembly typically includes a rigid wing rail, which is substantially aligned with a long point or heel rail element connected to a turnout traffic rail, and a relatively movable spring wing rail which is substantially aligned with a short point or heel rail element that is connected to a main line traffic rail. The movable wing rail is mounted with a yieldable free end, provides a substantially continuous support for the wheels of a rail car passing along the main line track, and often is closure-biased toward the frog long point rail by including a compression spring-type wing rail-closer element to the frog assembly. The movable wing rail, sometimes called a spring wing rail, has inherent lateral resiliency and is moved laterally away from the long point rail to provide a wheel flangeway between the long point rail and the spring wing rail when a railcar wheel flange traversing the rigid wing rail engages the spring wing rail free end and forces or causes that rail to be moved laterally to a full open position. After the last co-operating railcar wheel has passed through the assembly, the compression forces induced in the wing rail by bending and by the added rail-closer element cause the movable wing rail to be forcefully moved into its normal abutting relationship with the frog assembly long point rail.
U.S. Pat. No. 4,624,428, issued in the name of Frank, U.S. Pat. No. 5,544.848, issued in the names of Kuhn et al., and U.S. Pat. No. 5, 810,298, issued in the names of Young at al., all assigned to the assignee of this application, each disclose details of representative railroad spring wing rail frog assemblies known and utilized in the United States. While such frog assemblies have satisfactorily fulfilled different railroad trackwork application requirements, it has been observed that in instances in which the frog assemblies include a hold-open subassembly (sometimes also referred to as a holdback device) the frogs have been subjected to spring wing rail “overshooting” as a result of repeated, large-amplitude impact forces being imposed on the spring wing rail by the wheel flanges of railcar wheels moving through the assembly—especially at higher train velocities. The “overshooting” phenomenon can result in both frog assembly excessive wear and in possible substantial damage to the hold-open device.
We have discovered a new and useful railroad trackwork frog assembly construction which will improve frog assembly performance by eliminating the unwanted spring wing rail overshooting that often results from repeated high-impact forces being applied to she spring wing rail by successive railcar wheel flanges.
Other objects and advantages of the present discovery will become apparent during a careful consideration of the invention summary, description of the drawings, and detailed description which follow.
SUMMARY OF THE INVENTION
The novel railroad trackwork frog assembly of this invention is essentially comprised of a base plate element, a fixed wing rail element secured to the base plate element, a movable spring wing rail element mounted on the base plate element and having a free end portion, a spring wing rail hold-open element connected to the spring wing rail and to the base plate element, at least one shock absorber element also connected to the base plate element and to the movable wing rail element, and a coil compression spring element mounted on the shock absorber in surrounding and co-axial relation. Basically, the shock absorber element, which may be either a pneumatic-type shock absorber or a hydraulic-type shock absorber, functions to impose motion-resistance forces on the spring wing rail as it is being moved toward its fully-open condition, but does not impose any significant motion-retarding forces on the spring wing rail as it is being moved toward its fully-closed condition. The heavy-duty compression spring is combined with the shock absorber element to overcome friction forces that otherwise would tend to retard closing of the spring wing rail after a train has passed through the frog assembly.
In addition, the frog assembly may optionally include one or more slide-horn and hold-down subassemblies that function to control or maintain proper spring wing rail cross-section vertical orientation at all times during spring wing rail lateral movement, and may also optionally include an outrigger roller and inclined ramp subassembly of the type disclosed in U.S. Pat. No. 5,544,848.
REFERENCES:
patent: 253177 (1882-02-01), Breen
patent: 398975 (1889-03-01), Price
patent: 514119 (1894-02-01), Dodgson
patent: 515361 (1894-02-01), Price
patent: 926211 (1909-06-01), Roach
patent: 930709 (1909-08-01), Whiteman
patent: 4953814 (1990-09-01), Oswald et al.
patent: 5810298 (1998-09-01), Young et al.
Kuhn Stephen R.
Young Keith
ABC-Naco Inc.
Baker, Jr. Thomas S.
Jules Frantz F.
Morano S. Joseph
LandOfFree
Railroad spring wing frog with hold-open and shock dampening... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Railroad spring wing frog with hold-open and shock dampening..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Railroad spring wing frog with hold-open and shock dampening... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2486656