Note: Descriptions are shown in the official language in which they were submitted.
CA 02254511 2000-11-23
TITLE OF THE INVENTION:
Railroad Frog Assembly.
F:CELD OF THE INVENTION:
This invention relates. generally to railroad trackworks, and
particularly concerns railroar~ frr,n a~~o~,,~, :.... L~_
advantageously utilized in railroad trackwork intersections to
obtain a prolonged operating life for each assembly.
1
CA 02254511 1998-11-25
BACKGROUND OF T8E INVENTION:
Numerous different configurations of fixed-point railroad
frogs having spring-urged, flexible wing rails are utilized in
railroad trackwork system intersections in the United States to
provide through flangeways that enable railcar wheel flanges to
cross intersecting rails without encountering flange physical
interference. For two examples of such railroad spring rail frog
configurations see U.S. Patents Nos. 4,624,428 and 5,544,848 issued
in the names of Frank and Kuhn et al., respectively, and assigned
to the assignee of this patent application.
The flanged wheels of railcars passing through a fixed-point
railroad frog having a spring rail and in the direction of least
traffic flow repeatedly open the included flexible wing rail by the
widths of the wheel flanges, and the compression springs included
in the frog alternately and repeatedly force a return of the wing
rail to its closed position. This oscillating action of the
conventional spring-urged wing rail is undesirable in terms of both
the un-necessary frictional wear and metal fatigue that are
experienced.
Accordingly, a primary objective of the present invention is
to provide a railroad frog construction having an included spring-
urged flexible wing rail element with means for positively
retaining the wing rail in its fully-opened position following its
first actuation by the wheel flanges of a passing train set, and
until after all the flanged wheels of the train set have passed
through the frog.
2
CA 02254511 1998-11-25
Other objectives and advantages of the present invention, in
addition to providing a railroad frog assembly construction with a
significantly prolonged operating lifespan, will become apparent
from a full consideration of the detailed descriptions, drawings,
and claims which follow.
SUMMARY OF THE INVENTION:
The railroad frog assembly of the present invention basically
includes a frog fixed point, a frog flexible wing rail that abuts
the frog fixed point when in a wing rail fully-closed position and
that is spaced apart from the frog fixed point by the width of a
railcar wheel flange when flexed to a wing rail fully-opened
position, optional compression spring means co-operating with the
frog wing rail to assist in urging the wing rail toward its fully-
closed position, a switched magnet that co-operates with the flexed
frog wing rail in the wing rail fully-opened position, and control
means responsive to railcar wheel flanges passing through the frog
assembly to automatically switch the magnet between its "on" and
"off" conditions that respectively retain (hold-back) or release
the frog wing rail in or from the frog wing rail fully-closed
position.
BRIEF DESCRIPTION OF THE DRAWINGS:
Figure 1 is a schematic plan view of a preferred embodiment of
the railroad frog assembly of the present invention illustrating
the movable wing rail included in the assembly in a fully-opened
3
CA 02254511 1998-11-25
position and also illustrating an included electrical control
system;
Figure 2 is similar to Figure 1 except that the included wing
rail element is illustrated in a fully-closed position and that the
included control system is a hydraulic control system;
Figure 3 is a schematic illustration of the electrical control
system included in the railroad frog assembly of Figure 1;
Figure 4 is a schematic illustration of the hydraulic control
system included in the railroad frog assembly of Figure 2;
Figure 5 is a plan view of a portion of a railroad frog
assembly in accordance with the present invention but having a
modified arrangement for functionally coupling the frog assembly
flexible. wing rail element to the included wing rail hold-back
switched magnet element;
Figure 6 is similar to Figure 5 but illustrating another
modified arrangement of invention elements;
Figure 7 is similar to Figures 5 and 6 but illustrating still
another element arrangement modification; and
Figure 8 is a plan view of portions of a railroad frog
assembly in accordance with the present invention but utilizing
multiple switched magnet elements to retain the invention flexible
wing rail in its fully-open condition.
DETAILED DESCRIPTION:
Figure 1 illustrates a right-hand railroad trackwork
intersection l0 having a pair of main traffic rails 12 and 14 and
a pair of turnout traffic rails 16 and 18 in which main traffic
4
CA 02254511 1998-11-25
rail 14 intersects turnout traffic rail 16 at the frog assembly
designated 2o. Frog assembly 2o is basically comprised, in
addition to its base plate elements 22 and 24, of a frog fixed
point 26 (sometimes referred to as a frog "V-point"), a frog
flexible wing rail 28, a frog tfixed wing rail 30, an optional
compression spring closer element 32 that supplements internal
compressive forces within the flexed wing rail element when that
wing rail element is moved to its fully closed condition, and a
normally "off", switched magnet element 34. In Figure 1, flexible
wing rail 28 is illustrated in its open position to thus provide a
flangeway through the assembly for the flanges of railcar wheels
riding on turnout' traffic rail 16. Flexible wing rail 28
essentially abuts the side of fixed point 26 when in its closed
position, and is flexed or pivoted laterally about the point
designated 36 to an open condition whenever the flange of a railcar
wheel traversing the frog assembly either first engages the side of
closed flexible wing rail 28 to the left (Figure 1) of V-point 26
or engages the side of movable wing rail element 28 at its flared
end portion 38. Also included in trackwork intersection l0, but
not comprising a part of the present invention, are conventional
intersection rigid guard rails 40 and 42.
Additionally, frog assembly 10 is comprised of an electrical
control system 50 that actuates switched magnet means 34 between
its "on" and "off" conditions in response to sensing the presence
or absence of railcar wheels passing through the assembly.
Switched magnet means 34 may be either a conventional permanent
CA 02254511 1998-11-25
magnet or alternatively a conventionally-energized electro-magnet.
Magnet element 34 is activated when it is switched "on" and de-
activated when it is switched to an "off" condition. In the "on"
condition magnet 34 will magnetically attract and hold flexible
wing rail 28 in an open condition. In the "off" condition flexible
wing rail 28 is free to move, either with or without the additional
urging of a spring closer element 32, to a closed condition
abutting the side of fixed rail 26. Referring to Figure 3 in
particular, electrical control system 50 may be essentially
comprised of wheel sensor switches 52 through 58, resetting timer
-switches 60 and 62, an actuating solenoid 64 mechanically coupled
to switched magnet means 34, and circuit conductors interconnecting
those components to the positive and negative terminals 66 and 68
of a conventional electrical power source in the manner shown.
Sensor switches 52 through 58 may each have a conventional
proximity switch configuration, a conventional load cell
configuration, or the like - their function in the invention being
to detect and positively respond to the presence of an adjacently-
positioned railcar wheel. The railroad frog assembly system
sensors preferably are positioned adjacent the exterior side of
turnout traffic rail i6, which rail is most often a traffic rail of
least traffic density, and each functions to sense the immediate
presence or absence of a flanged railcar wheel passing through the
intersection. If the immediate presence of a railcar wheel is
sensed by a proximity switch or load cell that component s switch
element is closed, otherwise the sensor switch element normally
6
CA 02254511 1998-11-25
remains open.'
Preferably, sensor switches 52 and 54 are paired and are
located near one extreme of frog assembly 20. Similarly, sensor
switches 56 and 58 are also paired and are located near the other
extreme of frog assembly 20. Wheel sensor switches 52 and 56
function to complete a power circuit to and through actuating
solenoid 64 mechanically coupled to switched magnet means 34.
Sensor switches 54 and 58, on the other hand, function to complete
a power circuit to and through a respective one of normally-open,
resetting timer switches 60 and 62. Such timer switches are
preferably of an adjustable type, and have a pre-set time period
for switch element. closure. A closure delay period of
approximately 45 seconds is presently preferred. Thus, in response
to each sensing of an immediately-near railcar wheel passing
through frog assembly 10 and consequent switch closing by a wheel
sensor switch, its respective resetting timer switch 60 or 62 will
keep solenoid 64 actuated (energized) for a following 45 seconds or
other pre=set time period. Thus, following a period after the last
train set railcar wheel has passed through the intersection, all of
sensor switches 52 through 62 will be in an "open" condition,
solenoid 6! will be de-activated, switched magnet 3 ~ will be in an
"off" condition, and, since movable wing rail 28 is no longer
retained in an open condition, frog compression spring 32 will
force that rail to its closed position.
Figure 2 schematically illustrates a railroad trackwork
intersection 11 having components 12 through 42 that are similar to
7
CA 02254511 1998-11-25
the like components of intersection 10 but having a hydraulic
control system 70 rather than an electrical control system such as
control system 50 for regulating the switching of switched magnet
means 34 between its "on" and "off" conditions. Control system ii
is particularly distinguished by the inclusion of a railcar wheel-
activated, single-acting, spring-return mechanical pump element 72
that functions both as a sensor of the presence or absence of each
railcar wheel passing through frog assembly 20 and as an energy
source for powering control system li. Also, Figure 2 illustrates,
using broken lines, the schematic placement of a pair of wheel-
activated mechanical pumps 72A of an alternate-configuration
control system 70A that may be utilized as an alternate to control
system 70.
Figure 4 provides additional details of the hydraulic elements
preferably included in control systems 70 or 70A. Element 72 is
the above-mentioned single-acting, spring-return mechanical pump
and has an internal piston element 74 that is connected to a
reciprocable, wheel-actuated plunger element 76. Pump element 72
is made a single-acting pump by reason of the check valves 78 and
8o included in connecting hydraulic fluid flow lines 82 and 84.
Internal compression spring element 78 of mechanical pump 72, in
the absence of wheel tread forces imposed on plunger element 76,
urges piston element 74 to the position shown in Figure 4.
As the wheel treads of successive railcars passing through
frog assembly ii repeatedly depress plunger element 76 pressurized
hydraulic fluid is pumped from reservoir 86 to single-acting,
8
CA 02254511 1998-11-25
spring-return hydraulic actuator 88 via fluid flow lines 90 and 92.
The piston rod element 94 of hydraulic actuator 88 is mechanically
coupled to the actuating arm of switched magnet element 34.
Hydraulic system 70 also includes an adjustable bleed-off valve 96,
a conventional spring-powered pressure accumulator 98, a valued
pressure gage 100, and an adjustable pressure relief valve 102 set
for system maximum pressure. System relief valve 102 is set to
hold a system pressure that is significantly greater than the
pressure required at actuator 88 to overcome the spring forces of
actuator 88/magnet 3~l and thereby switch the magnet from its normal
"off" condition to its "on" condition. Bleed-off valve 96 is
adjusted to control~the rate of fluid flow from line 92 where such
rate establishes a predetermined time delay (e. g., 45 seconds)
between the time the last railcar wheel of a train set passing
through frog assembly 11 depresses pump plunger 76 and time that
permanent magnet 34 is switched to its normal "off" condition.
Should a train set stop before the its last railcar wheel has
cleared the frog assembly, permanent magnet 34 will be switched off
following the preset delay and wing rail 28 will be prematurely
closed by compression spring element 32. However, the arrival of
the next railcar wheel to pass either a sensor switch (52 or 54) or
a wheel-actuated pump (72 or 72A) will cause its respective control
system to return magnet 34 to its switched "on" condition thereby
retaining wing rail 28 in its open position until such time as the
preset time delay has elapsed following passage of the last train
set railcar wheel.
9
CA 02254511 1998-11-25
Depending upon particular application requirements, different
modifications may be advantageously made to the arrangement of
invention elements illustrated in Figures 1 and 2. In Figure 5,
for instance, we illustrate the advantageous inclusion in the
invention of a rail horn fitting 110 which is securely bolted to
the frog flexible wing rail 28 with its longitudinal axis oriented
substantially at right angles to the longitudinal axis of the wing
rail, and which is positioned intermediate flexible wing rail 28
and switched magnet means 34. Horn fitting 110 is provided with an
attached (as by welding) attraction face element 112 that is
oriented substantially at a right angle relative to the
longitudinal axis of horn fitting 110. Attraction face element 112
engages, and is retained in position by, switched magnet means 34
when switched on and after flexible wing rail 28 has been moved
from its Figure 5 closed condition through the distance d by the
action of the flange of a railcar wheel passing through the frog
assembly. As previously suggested, the distance d generally equals
or is slightly greater than the flange thickness of a standard
railcar wheel. The Figure 5 modification for railroad frog
assembly 10 is advantages when it is desired to locate switched
magnet means 34 and it switched magnetic flux field more distant
from wing rail 28 than as shown in Figures 1 and 2.
In Figure 6 we schematically illustrate another invention
modification involving the use of an intermediately-positioned rail
horn fitting. The Figure 6 horn fitting is referenced with the
numeral 114 and is similar to horn fitting in function but does not
CA 02254511 1998-11-25
include an attached right-angled attraction face element. Instead,
horn fitting 114 is provided with a solid side 116 that faces
switched magnet means 34. Solid side 116 provides an attraction
face that engages and is retained by switched magnet means 34 when
the magnet is switched on. As in the Figure 5 arrangement, through
use of the attached and intermediately positioned horn fitting 114,
switched magnet means 34 may be positioned farther from flexible
wing rail 28 than in the Figure 1 and Figure 2 arrangements.
In Figure 7 we illustrate an arrangement of invention elements
which is somewhat similar to the arrangement of Figure 6 save that
horn f fitting 114 also co-operates with a conventional flexible wing
rail hold-down fitting 118 of the type disclosed in U.S. Patent No.
5,595,361 issued in the name of Remington et al.
Also, and as illustrated in the drawings at Figure 8, in some
applications of railroad frog assembly 10 it is advantageous to
utilize multiple switched magnet elements 34 spaced apart along the
longitudinal axis of flexible wing rail element 28. The Figure 8
arrangement illustrates the use of two such switched magnet
elements separated by an intermediately-positioned closure spring
element 32.
Various changes may be made in the relative shapes,
proportions, and sizes of the components disclosed without
departing from the scope, meaning, or intent of the claims which
follow.
We claim our invention as follows.
li
