Railroad spring wing frog with hold-open and shock dampening elements

An improved railroad trackwork spring wing frog assembly having a selectively releasable hold-open subassembly for the spring wing rail is provided with a combined compressible shock absorber and compression spring that are functionally connected to the assembly spring wing rail and to the assembly base plate, and that function to generate an opposing force in connection with opening movement of the spring wing rail and an augmented force in connection with closing movement of the spring wing rail.

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.

DETAILED DESCRIPTION
 Referring to FIGS. 1 and 2, a left-hand spring frog assembly 100 is shown
 inserted in one rail 12 of a pair of turnout rails 12, 14 and in one rail
 16 of a pair of mainline rails 16, 18. Spring wing rail frog assembly 100
 is mounted on a base plate element 20 which provides a level foundation
 for the frog assembly invention and which maintains the elements which
 comprise the frog assembly in their proper inter-relationship during
 shipping, subsequent installation, and operation in a railroad trackwork.
 Frog assembly 100 is functionally positioned to permit flanged railcar
 wheels riding along rail 12 to cross rail 16 and flanged railcar wheels
 riding along rail 16 to cross rail 12. A conventional switch stand for
 directing railcars from rail pair 12, 14 to rail pair 16, 18 and vice
 versa is necessary for the trackwork but does not comprise any part of
 invention 100.
 As illustrated in FIG. 2, spring wing rail assembly 10 has a V-point
 element 22 mounted on base plate 20 and has a rail end 24 which upon frog
 installation is joined, as by welding, to turnout line rail 12 to provide
 a connection for that rail to frog assembly 100. An included rail end 26
 is joined, as by welding, to mainline rail 16 to connect that rail to frog
 assembly 100.
 The generally-curved, fixed wing rail element 30 of frog assembly 10 has an
 end 32 that is connected on frog installation to a section of turnout rail
 12. The end 34 of fixed wing rail element 30 is preferably flared so that
 the flange of a railcar wheel moving through the assembly from the FIG. 2
 left will not abruptly strike the wing rail free end. Also, fixed wing
 rail element 30 is rigidly secured to base plate element 20 by
 conventional means such as plate clips (not shown). Thus, wing rail
 element 30 is a relatively immovable member of frog assembly 100.
 The yieldably-mounted spring wing rail element 40, which is the primary
 movable member of frog assembly 100, has an end 42 that upon installation
 is joined to a section of mainline rail 16. Element 40 also has a flared
 end 44 to avoid being accidentally struck by the flange of a railcar wheel
 moving toward V-point rail element 22 from the FIG. 2 left. It should be
 noted that spring wing rail 40 at its principal body section and at its
 free end 44 is not fixedly secured to base plate element 20 either by
 conventional plate clips or otherwise. Lateral movement of spring wing
 rail element 40 relative to base plate 20, however, is resisted by sliding
 friction forces sourced in the weight of the spring wing rail and the
 weight of railcars riding on the spring wing rail.
 When the flange of a car wheel engages spring wing rail 40 at its free end
 44 and causes it to move laterally so that a flangeway is provided between
 V-point 22 and spring wing rail 40, rail 40 is basically stressed and
 flexed from the point of wheel engagement to where it is first rigidly
 secured to base plate element 20, usually at an assembly spacer block (not
 shown). Spring wing rail element 40 is acting essentially as a
 cantilevered beam.
 The railroad trackwork installation shown in FIG. 1 also typically includes
 a pair of conventional guard rail elements 46, 48 having flared ends which
 are positioned at turnout rail 14 and at mainline rail 18, each in
 spaced-apart relation to the adjacent rail by a distance that is slightly
 greater than the standard railcar wheel flange thickness, respectively.
 In addition, and as shown in FIGS. 1 and 2, the railroad spring frog
 assembly 100 typically includes a selectively releasable hold-open element
 108 and one or more shock absorber subassembly 102 in its construction and
 also, optionally, one or more conventional hold-down subassembly 52, each
 such subassembly 102 being functionally connected to spring wing rail 40
 and to base plate element 20. Hold-open element 108 generally is a device
 of the type disclosed in U.S. Pat. No. 5,806,810, issued Sep. 15, 1998 in
 the names of Young et al. and assigned to the assignee of this patent
 application, or disclosed in co-pending Applications for U.S. Letters
 Patent Ser. Nos. 09/251,841 filed Feb. 17, 1999 and 09/251,620 filed Feb.
 17, 1999 also assigned to the assignee of this patent application.
 While in some applications a single shock absorber assembly 102 may be
 effective to prevent spring wing rail overshooting, in the FIGS. 1 and 2
 frog assembly construction a pair of spaced-apart shock absorber
 subassemblies are provided for the purpose of eliminating repeated spring
 wing rail "overshooting" that would otherwise occur as a consequence of
 the impact forces imposed by the successive railcar wheels of a train
 passing through the frog assembly.
 Hold-down subassemblies 52 function, during instances when a railcar wheel
 flange engages spring wing rail 40 and causes lateral displacement of rail
 40, to limit upwards vertical movement of the rail and yet permit rail
 lateral movement.
 Each included shock absorber element 102 is combined with a surrounding
 co-axial, heavy-duty compression spring element 53, and the shock absorber
 end extremes are connected to spring wing rail 40 and base plate element
 20 through the semi-spherical slip joints 104 and 106, with the
 semi-spherical socket portions of the semi-spherical slip joints being
 provided in mounting brackets 64 and 70, respectively. Alternatively, more
 conventional tang and clevis connections may be utilized in lieu of
 semi-spherical slip joints 104 and 106. The hold-open element included in
 the frog assembly is referenced by the numeral 108.
 In FIG. 4 we provide details of pneumatic-type shock absorber subassembly
 102 including its connections to spring wing rail element 40 and to base
 plate element 20. Basically, the hollow, small-diameter end 60 of shock
 absorber 50 co-operates through a tang and clevis pivot connection 62 with
 the mounting bracket 64 that is bolted to assembly base plate element 20.
 The hollow, large-diameter end 66 of shock absorber assembly 50 is
 connected to spring wing rail 40 through a semi-spherical slip joint 106
 and mounting bracket 70 and of a co-operating cylinder end 114 that is
 connected to base plate element 20 through a semi-spherical slip joint 104
 and mounting bracket 64. Because shock absorber subassembly 110 includes
 heavy-duty compression spring element 53 in surrounding and co-axial
 relation to the piston and cylinder ends 112 and 114, such shock absorber
 ends 112 and 114 are each provided with a large-diameter integral flange
 116 against which an end of spring element 53 will abut. Pivot connections
 104 and 106 are provided to achieve proper shock absorber self-alignment
 throughout the range of motion of the invention spring wing rail element.
 Small-diameter end 60 of shock absorber element 102 is provided with a
 piston-head closure member 72 having an integral one-way, spring-biased
 check valve 73 and an integral orifice passageway 74. Basically, check
 valve 73 is sized to have a large flow rate at a given pressure
 differential for its one-way flow in comparison to the flow rate of
 orifice passageway 74 at the same pressure differential. Orifice
 passageway 74 is provided in shock absorber subassembly 50 primarily for
 the purpose of achieving long-term pressure equalization between the
 interior chambers of shock absorber ends 60 and 66.
 Also included in subassembly 102 are conventional piston head O-ring
 pressure seal 76 and conventional debris wiper ring 78. Not shown in the
 drawings is a conventional valved inlet port that must be provided in
 shock absorber subassembly 102 for the purpose charging the shock absorber
 interior with pressurized air or other gaseous fluid.
 Note also that the ends of shock absorber 102 are provided with integral,
 large-diameter flanges 116 that serve as abutments for the ends of
 heavy-duty compression spring element 53. Basically, embodiment 100 of the
 spring wing rail frog assembly of the present invention is utilized in
 applications wherein increased friction is encountered in connection with
 the opening and closing of spring wing rail 40 such that an increased
 closing force is desired. Such is provided by the additionally included
 heavy-duty compression spring element 53 of shock absorber assembly
 embodiment 102.
 In FIG. 5 we provide schematic construction details of a hydraulic-type
 shock absorber subassembly 110 that may be utilized in the practice of the
 present invention, particularly when the overshoot impact loads imposed on
 the frog assembly spring wing rail are especially large in magnitude. As
 shown in FIG. 6, subassembly 110 is basically comprised of a hydraulic
 piston end 112 having an integral piston rod 120 and attached piston 122
 and of co-operating hydraulic cylinder end 114. Piston 122 is provided
 with an integral one-way check valve 73 and an integral orifice passageway
 74 and also the O-ring seals 76.
 By further including the co-axial and surrounding compression spring 53 in
 element 102 we are able to provide a frog assembly with subassembly
 functions that previously were achieved with two separate subassemblies
 each with an individual function, with a reduction of separate component
 mounting positions, and also with a reduction in number of required
 component parts.
 Other component shapes, sizes, and materials may be substituted for the
 component shapes, sizes, and materials described above to obtain the
 advantages of this invention and without departing from the claimed scope
 of the invention.
 We claim as our invention the apparatus defined by the claims which follow.