U.S. patent number 4,069,590 [Application Number 05/702,350] was granted by the patent office on 1978-01-24 for rail wear measurement system.
This patent grant is currently assigned to Southern Railway Company. Invention is credited to Robert J. Effinger.
United States Patent |
4,069,590 |
Effinger |
January 24, 1978 |
Rail wear measurement system
Abstract
A system for measuring rail wear includes an assembly movable
along a railroad track and having displacement pickups adapted to
respectively bear upon points on a top surface and on an inner side
surface of each rail for the measuring of rail wear at these
surfaces. Entered into the system are unworn top and side rail
surface measurements taken relative to a known unworn feature of
the rail at selected points. The assembly includes a probe element
for each rail which bears upon an unworn portion of the worn rail
so as to facilitate measurement of rail wear by the pickups in
relation to the unworn top and inner side rail measurements. With
the use of transducers, the pickups are adapted to generate signals
in accordance with the mechanical displacement of the top surface
and the side surface points relative to the measured unworn top and
side surface points which signals are then converted to analog
voltage levels which may be displayed on digital panel meters.
Analog-to-digital converters may then provide the input to a data
recording system.
Inventors: |
Effinger; Robert J. (Grafton,
VA) |
Assignee: |
Southern Railway Company
(Washington, DC)
|
Family
ID: |
24820869 |
Appl.
No.: |
05/702,350 |
Filed: |
July 2, 1976 |
Current U.S.
Class: |
33/523; 33/1Q;
33/505 |
Current CPC
Class: |
B61K
9/08 (20130101); G01B 7/28 (20130101) |
Current International
Class: |
B61K
9/08 (20060101); B61K 9/00 (20060101); G01B
7/28 (20060101); G01B 007/28 () |
Field of
Search: |
;33/1Q,144,146,174R,174L |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,295,442 |
|
May 1962 |
|
FR |
|
938,570 |
|
Feb 1956 |
|
DT |
|
Primary Examiner: Aegerter; Richard E.
Assistant Examiner: Stearns; Richard R.
Claims
What is claimed is:
1. A system for measuring rail wear includes an assembly associated
wtih a rail of a railroad track, said system including means for
moving said assembly along the rail, said assembly comprising means
mounting first and second movable displacement pickups to
respectively bear upon first and second points on a top surface and
on an inner side surface of the rail of said track, said means
further mounting a probe element interconnected with said pickups
to bear upon an unworn portion of said rail, said probe element
being shaped to simultaneously engage top and inner side surfaces
of said unworn portion, said pickups including means to generate
first and second proportional electrical signals in accordance with
the displacement of said first and second points respectively from
points relative to said top and inner side surfaces of said unworn
portion of said rail, and means connected to said pickups for
converting the signals produced thereby to analog voltage levels
for display on digital panel meters provided for such display.
2. The system according to claim 1 wherein said mounting means
further comprises an upstanding frame on which said pickups and
said probe element are mounted for independent movement relative to
said frame toward and away from said rail, said frame being mounted
for pivotal movement toward and away from said rail about an axis
parallel to said rail of said track respectively between an
operative and an inoperative position.
3. The system according to claim 2, wherein said first and second
pickups are mounted on pickup arms each spring mounted on said
frame so as to be resiliently urged respectively toward said top
and said inner side surfaces of said rail of said truck.
4. A system for measuring rail wear includes an assembly associated
with a rail of a railroad track, said system including means for
moving said assembly along the rail, said assembly comprising an
upstanding body member, means on said body member movable axially
with respect thereto, a shaft extending downwardly of said body
member and being mounted on said means, said shaft having a contact
probe element thereon extending radially outwardly at one end
thereof and shaped to bear upon top and inner side surfaces of an
unworn portion of the rail, first and second displacement pickups
carried by said means adpated to respectively bear upon first and
second points on a top surface and on an inner side surface of said
rail, said pickups including means to generate first and second
proportional electrical signals in accordance with the displacement
of said first and second points relative to said top and inner side
surfaces of said unworn portion of said rail, means connected to
said pickups for converting the signals produced thereby to analog
voltage levels for display on digital panel meters provided for
such display, pressure means operable on said means on said body
member for shifting said probe element and said pickups together in
one direction toward said rail, means for rotating said shaft for
movement of said probe element into and out of contact with said
unworn portion, and means for shifting said probe element and said
pickups together in an opposite direction away from said rail when
said probe element is moved out of contact with said unworn
portion.
5. The system according to claim 4, wherein said means on said body
member and said pressure means includes a pneumatic cylinder and
piston unit, a rotary valve disposed within said piston and being
coupled to said shaft for rotation therewith, exhaust ports in said
unit aligning with an exhaust port in said valve upon movement of
said shaft in said one direction and upon rotation of said shaft,
enabling said shaft to be moved in said opposite direction by said
means for shifting in said opposite direction, while continuing its
rotation.
6. The system according to claim 5, wherein said means for shifting
in said opposite direction comprises a cushion spring within said
body member urging said piston to move in said opposite direction,
whereby upon exhaust of pressure through said aligned ports, said
probe element and said pickups are shifted in said opposite
direction.
7. The system according to claim 4, wherein said assembly further
comprises a frame on which said body member is mounted for pivotal
movement about an axis perpendicular to said shaft, and spring
means coupling said body member with said frame for resiliently
urging said probe element into contact with said unworn portion of
said rail.
8. The system according to claim 7, wherein rail feelers are
provided on said frame for spacing said frame from said rail a
predetermined distance such that said probe element will intimately
contact said unworn rail portion during rotation of said shaft.
9. The system according to claim 4, wherein said probe element
includes upper and lower spaced probe spheres respectively for
point contacting an undersurface of the head of said rail and a web
surface of said rail.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to a testing apparatus and more
particularly to such an apparatus designed for measuring top and
side wear of the rails along a railroad track.
Problems of undue rail wear have beleaguered the rail industry
throughout its history and are becoming more acute now that higher
speed rail transportation systems are developed. Railroad tracks
must be constantly monitored for rail wear and worn rail sections
of the track must be replaced for reasons of safety, riding
comfort, riding stability and the like. In the past, it has been
customary to manually measure rail wear along the tops and inner
surfaces of both rails by means of a rail gauge. Such a gauge is
normally designed as having a template contoured to an unworn
feature of the rail at the undersurface of the rail head and at the
upper side surface of the rail web. Such contour varies for
different gauges used in measuring different sized rails of 100
pounds, 115 pounds and 132 pounds of presently usable stock. Each
gauge has a pair of axially movable plungers for respectively
making point contact with the top and inner side surfaces of the
rail head. These plungers are calibrated so that readings may be
taken therefrom depending on their inward movement from zero
calibration in accordance with top surface and side surface rail
wear. The process for measuring rail wear using such gauges is
obviously tedious and time consuming especially since manual
recordings must be made at predetermined mileposts along the
tracks. Recording accuracy is therefore difficult to maintain using
this inefficient system.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide a
system for measuring top and side rail wear along a railroad track
in an automatic, efficient and economical manner.
Another object is to provide such a system including an assembly
movable along a railroad track wherein pickups are arranged on the
assembly in point contact with the tops and inner side surfaces of
the rails, and a probe element bears against an unworn portion of
the rail so as to permit the pickups to measure rail wear in
relation to known rail measurements entered into the system
respecting unworm top and inner side surfaces of the reference
rail. Transducers associated with these pickups generate electrical
signals in accordance with the mechanical displacement of the top
and side surface rail points, which signals may be converted into
output readings related to left rail top wear, left rail side wear,
right rail top wear and right rail side wear measurements.
Other objects, advantages and novel features of the invention will
become more apparent from the following detailed description of the
invention when taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are respectively side elevation and top plan views of
a trailer housing the present assembly and being towed along the
railroad track by a truck;
FIGS. 3 and 4 are respectively side wear and top wear measuring
portions of the assembly shown in separate Figures in the interest
of clarity;
FIG. 5 is an enlarged view of a portion of a rail showing the
pickups and the reference element of the assembly bearing
thereagainst;
FIG. 6 is an enlarged vertical sectional view of the reference
element assembly according to the invention;
FIG. 6A is a top plan view of the assembly of FIG. 6 taken
substantially along line 6A--6A thereof;
FIG. 6B is a sectional view of the cylinder and piston unit taken
substantially along line 6B--6B of FIG. 6;
FIG. 7 is a control system block diagram for the measuring assembly
according to the invention; and
FIG. 8 is a block diagram for the data system embodying the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings wherein like reference characters refer
to like and corresponding parts throughout the several views, as
assembly generally designated 10 for measuring top and side wear of
the left rail is shown in FIGS. 1 and 2, an identical assembly
being associated with right rail 12 for the measuring of top and
side rail wear although not shown in the interest of clarity. This
assembly is mounted within a frame generally designated 13 in FIGS.
1 and 2, and a measuring frame actuator 14 is likewise mounted
within this frame in association with each rail (only one being
shown) for a purpose to be more fully described hereinafter. The
assemblies, frames and actuators are housed within a trailer 15
having rail wheels 16 in rolling engagement with the rails as in
any normal manner, the wheels being elevated out of engagement
therewith by means of pivotable ground wheels 17, in a manner
forming no part of this invention, when it is desired to tow
trailer 15 along the ground. The trailer is coupled in any normal
manner to the rear end of a towing vehicle or truck 18 which is
equipped as having a power generator, and observer's seat, a
driver's seat, a recorder, a remote control station and the like,
all being omitted from FIGS. 1 and 2 in the interest of clarity.
The truck likewise has rail wheels 16 and ground wheels 17
similarly as provided for the trailer and operable in like manner.
An air compressor and tank 19 is operatively mounted within the
trailer for a purpose which will be made more clear hereinafter.
The purpose of the truck is to provide motive and operating power
for the measuring and control system housed within the trailer. The
truck also provides a housing and a suitable environment for the
recording system which will become more apparent from the
subsequent description.
FIGS. 3 and 4 are similar in that they both show measuring assembly
10 of the invention as specifically designed for measuring side
wear rail as in FIG. 3 and for measuring top rail wear as in FIG.
4. Two illustrations of the assembly are made in order to more
clearly describe the parts relating to side rail wear and top rail
wear measurement. The assembly comprises a cylindrical body member
21 having a top flange 22 with trunnions 23 thereon (FIG. 6)
coupled with rods 24 pivotally mounted on uprights 25 of frame 13.
An elongated shaft 26 having a reference probe 27 at the free end
thereof is disposed within body 21 for axial movement. As seen in
FIG. 5, the probe extends radially outwardly of the shaft. An
inverted cup-shaped piston 28 is mounted for axial sliding movement
within a pneumatic cylinder casing 29, and is prevented from
rotation relative to cylinder 29 by a tongue and vertical groove
arrangement, for example, located on the side walls of the piston
and cylinder. The casing is mounted to body 21 at the top end
thereof. And, an air line 31 leads to the interior of the cylinder
behind the piston as clearly shown in FIG. 6.
Reference probe 27 includes a pair of spaced spheres 27a, 27b (FIG.
5) which may be of tungsten carbide material for increasing the
useful life thereof since, as will be shown, these spheres bear
against an unworn portion of the rail during the measurement
operation. The assembly of FIG. 6 further includes a coil spring 32
bearing against a cap 33 at the open end of the piston, and a
rotary valve 34 having closed ends is keyed to shaft 26 by means of
a pin 30 for rotation and axial movement therewith, and is disposed
within piston 28.
As seen in FIGS. 6 and 6B, shaft 26 is provided with a coaxial
elongated groove 26a relatively disposed to the piston as in FIG.
6. Rotary valve 34 has an elongated opening 34a in the annular side
wall thereof extending parallel to the valve end walls, the opening
extending throughout approximately 300.degree.. The rotary valve is
disposed with the remaining 60.degree. wall portion 34b in the
plane of opening 34a, while in a position of rest, facing an
exhaust opening 28a provided in the side wall of piston 28, as
shown in FIG. 6. And, the valve is free to rotate within its piston
about the axis of shaft 26 so that its opening 34a will move into
alignment with exhaust opening 28a. As will be seen from the
operation description hereinafter, opening 28a is brought into
alignment with an exhaust opening 29a provided in the side wall of
cylinder 29 and lying directly below opening 28a, upon downward
movement of the piston. Also, elongated openings 29b are provided
in cylinder 29 to facilitate relative axial movement between cap 33
and the cylinder as arms 33a on the cap extend through openings
29b.
Shaft 26 is connected to a flywheel 35 turned by a motor 36 through
a drive belt 37 to thereby effect rotation of the shaft. The motor
is connected in any normal manner to a source of power within the
system. Uprights 25 are fixedly interconnected at their upper ends
by a rod 38 which is in turn mounted on a portion of a frame 20 of
trailer 15. Frame actuator 14, likewise mounted on a portion of
frame 20, includes a piston and cylinder unit 39, as shown in FIGS.
3 and 4, with the piston thereof connected to a crank arm 41 which
is in turn fixedly connected to rod 38 so that, upon reciprocation
of the piston in the direction of the double arrows shown in these
Figures, rod 38 is axially rotated so as to effect pivotal movement
of the entire frame 13 and assembly 10 about the axis of rod 38.
The assembly may therefore be stowed in an inoperative position
away from its associated rail when not in use in the position shown
in FIGS. 3 and 4. A lower transverse member 42 of the frame
interconnects uprights 25 near their lower ends so as to slightly
overhang a portion of frame element 20a to which guide feelers 43
are mounted at spaced distances from the frame uprights in fore and
aft directions. These feelers are maintained in contact against an
inner side surface of rail 12 by means of actuator 14 which effects
pivotal movement of the frame toward the rail. Feelers 43 therefore
establish bearing points for frame 13 in the operational position
thereof shown in FIGS. 3 and 4. The feelers are likewise axially
adjustable for setting the distance that the frame is spaced from
the rail so as to insure that the probe element will intimately
contact the unworn portion of the rail upon rotation of the shaft
as will be more clearly seen hereinafter.
Probe element 27 is spring loaded, by means of a spring 44
connected to an arm 45 on one of the rods 24 and to an arm 46 on
one of the uprights, so as to maintain sphere 27b of the reference
probe in biased point contact with an inner side surface 48 of the
web of rail 12.
A side wear feeler of pickup stylus 49 is positioned to bear upon
an inner side surface 51 of the rail head. This stylus is secured
to a pickup arm 52 which is pivotally connected to a link arm 53
connected to an arm 33a of cap 33 as more clearly shown in FIG. 6.
Pickup stylus 49 is spring loaded to bear upon a point on side
surface 51 of the rail head by means of a spring 54 connecting
pickup arm 52 with a bracket 55 mounted on one of the frame
uprights. A transducer 56 connected between pickup arm 52 and body
21 of the assembly is disposed perpendicular to arm 52 for sensing
side wear values of inner surface 51 of the rail head. This
transducer may be a standard linear variable differential
transformer (LVDT) as typically shown in U.S. Pat. No. 3,166,852,
the particulars of such LVDT being specifically incorporated herein
by reference. The side wear feeler or pickup stylus 49 is protected
by guide feelers 43 as aforedescribed, and is positioned by these
feelers when they are adjusted toward and away from side surface 51
of the rail. And, by reason of the arrangement described for the
side wear pickup, it is assured of contacting the rail's side
surface at a predetermined location and is displaced laterally in
accordance with the amount of wear. Also, it should be pointed out
that feeler 49 includes a tungsten carbide contact element to
extend its useful life.
A top wear pickup stylus or feeler 57 is positioned to bear upon
the top surface 58 of the rail head as shown in FIGS. 4 and 5. This
stylus is secured to a pickup arm 59 which bears against shaft 26
of the assembly by means of a positioning link 61. Also, the top
wear pickup stylus is spring loaded for bearing upon a point on the
top surface of the rail head by means of a coil spring 62
connecting pickup arm 59 with a bracket 63 mounted on frame member
42. Pickup arm 59 is likewise pivotable about the axis of its link
61 and is spring loaded by means of a spring 64 interconnecting
pickup arm bracket 65 with bracket 66 mounted on upright 25. Arm 59
is connected to another of the arms 33a of cap 33 by means of a
link 60. Top wear values of the rail are sensed by a transducer 67
disposed between sections of link 60 and lying parallel to shaft
26. This transducer is likewise a linear variable differential
transformer (LVDT) of known construction usable as a sensor in the
art. The LVDT sensors for wear measurement usable herein are
environmentally sealed, rugged, shock resistant units. They are so
designed that any error thereof due to sensor non-linearity will
not exceed 0.25 percent of full scale output, and the operating
temperature range thereof is -65.degree. to +300.degree. F. The
signal conditioning will provide a 2V RMS, 2500 Hz excitation for
the LVDT sensor and input, zero and span controls for the 10V DC
demodulated output. The 0 to 10V DC output variation will be
converted to 100 discrete bits corresponding to 0 to 1.00 inches of
wear. The output linearity of the analog-to-digital converter is
.+-. 1/2 of the least significant bit, which is a digital accuracy
of .+-. 0.005 inches. These A/D converter outputs are stored in the
memory circuits when a data pulse is received and then scanned and
printed by a digital printer or scanner.
In an inoperative position assembly 10 and its frame 13 will be
rotated by actuator 14, connected with a suitable power source (not
shown), inwardly toward the center of the trailer and away from its
associated rail. Shaft 26 in this position is retracted into body
21 by means of spring 32 so that probe element 27 will be above the
rail top in the shadow of the flange of the trailer wheels. Side
wear pickup stylus 49 will be protected from damage in such
position by guide feelers 43 which are sufficiently rugged to
withstand passing through turnout in opposite directions of vehicle
movement. And, the top wear pickup stylus 57 remains in the shadow
of the tread of a ground wheel 17 of the trailer for
protection.
Turning now to FIG. 7, the control system which incorporates the
present apparatus will be described in block diagram form. An
Operation Mode Selector switch will be provided to permit three
methods of controlling rail measurements: the MANUAL operation
mode, where the operator presses a switch to initiate each rail
wear measurement cycle; the JOINT initiated mode, wherein a
measurement cycle is automatically initiated for each individual
rail; and the PRESET distance mode, where measurements are
automatically made on welded rails at selected intervals. An
optical type Wheel Tachometer is coupled to the speedometer cable
of truck 18 to provide distance information to the control system
as well as to the data system. This tachometer is designed to
provide approximately 68 pulses per foot at all speeds down to zero
mph. It utilizes light emitting diodes as light sources for maximum
life and to withstand rough usage. The Digital Tachometer will
amplify the pulses from the Wheel Tachometer, compute and display
speed and provide overspeed signals to each Sequence Controller.
Speed will be displayed in miles per hour as a two-decade number
(up to 99 mph) with an accuracy of 1 mph.
The Joint Sensors are feeler operated switches mounted on truck 18
about 28 feet ahead of reference elements 27, 27'. (It should be
noted that with reference to FIG. 7 illustrating right and left
rails a prime (') will be used to identify elements of the
apparatus associated with the left rail.) They will be actuated by
joint bars and by obstructions that are likely to damage the
reference elements during deployment. In the JOINT operation mode,
actuation of a Joint Sensor will reset and start a four-decade
counter in the Joint Recognition Controller for that rail. A count
typically between 1.8 and 3.2 feet will identify a joint bar, and
if identified, will start a four-decade footage counter in the
Sequence Controller for that rail. When this count is typically 30
feet, the Reference Probe will have passed the joint and the
Sequence Controller will initiate the measurement cycle.
Obstructions less than typically 1.8 feet and greater than 3.2 feet
in length will stop the counter and inhibit measurements until
another joint bar is recognized.
In the MANUAL operation mode, the Enable Switch will start the
footage counter in the Sequence Controller and a single measurement
cycle will be initiated after typically 30 feet is counted. In the
PRESET DISTANCE mode the Sequence Controller will automatically
recycle when its footage counter reading is typically 40 feet.
Measurements will continue to be made at each preset distance until
the Stop Switch is depressed. In both the MANUAL and PRESET
DISTANCE modes, the measurement cycle will be inhibited when the
Joint Bar Sensor is actuated by an obstruction. However, recycling
in the PRESET DISTANCE mode will resume when the obstruction has
been passed. Each Joint Recognition Controller will have two
four-decade thumbwheels internally mounted to preset the minimum
and maximum lengths to be used for joint bar identification. Each
Sequence Controller will also have two four-decade thumbwheels, one
internally mounted for presetting the distance traveled before
initiating a measurement cycle (typically 30 feet) and the other
one for presetting the recycling distance (typically 40 feet) to be
used in the PRESET DISTANCE mode on welded rails. Since the Wheel
Tachometer will provide approximately 68 counts per foot, the
resolution of both Joint and Sequence Controllers will be
approximately 0.015 feet.
When one of the Sequence Controllers initiates a measurement cycle,
it will open a valve (not shown) actuated by an Air Solenoid in the
regulated air line 31 leading to the air cylinder 29 for that rail.
Air pressure acting against piston 28 will then downwardly drive
shaft 26 and its reference probe 27 as well as rotary valve 34 and
cap 33. This motion momentarily closes a plunge switch 68 mounted
on body 21 in the path of a contact element E shown schematically
in FIG. 6, thereby latching a Solenoid Clutch (FIG. 7) with the
rotating flywheel by means of a solenoid 69 (FIG. 6A). At this
position, probe 27 is disposed approximately 60.degree. away from a
perpendicular to the rail and wall 34b will be in a position of
FIG. 6 relative to openings 28a and 29a which are now co-axially
aligned. Flywheel 35 will then rotate shaft 26 and its reference
probe 27 throughout 360.degree., in the direction of the arrow in
FIG. 6, from such position, at which time the Solenoid Clutch is
mechanically unlatched as lever arm 71 thereof is tripped by an
extension element 72 keyed to shaft 26 as typically shown in FIG.
6A. However, after approximately 60.degree. of rotation sufficient
for wall 34b to be rotated out of alignment with openings 28a, 29a,
the air pressure will begin to exhaust through groove 26a, opening
34a and ports 28a, 29a which are now aligned in such a depressed
and turned condition of the shaft. It will be seen from FIGS. 6 and
6A that a passageway to exhaust opening 29a is established from the
air inlet 31 via groove 26a, opening 34a, and opening 28a. Upon
exhaust, the return spring forces the piston upwardly causing
reference probe 27 to be seated firmly on the underside of the rail
head as typically shown in FIG. 5, while scrubbing the rail until
it reaches its normal position. A reed switch 73, actuated by a
magnet 74 as shown in FIG. 6A, will signal the data memory circuits
to store the wear measuring data, at the time reference probe 27 is
rotated to a position perpendicular to its associated rail. Spring
32 thereafter completes the upward stroke of shaft 26 while its
rotation is being completed. Also, it should be noted that downward
movement of the probe as aforedescribed causes feelers 49 and 57 to
be accordingly moved downwardly during which time feeler 49 slides
against surface 51 of the rail head and feeler 57 bears against top
surface 58 of the rail head. A spring 70, which is heavier than
spring 62, serves to cushion the initial impact between the top
feeler and surface 58. This spring is shown in FIG. 4 spanning the
sections of link 60 which are connected by pickup 67. Also, the
fixed distance between pickup 49 and sphere 27a assures that this
side pickup will be always positioned against surface 51 of the
rail head at the location shown in FIG. 5. And, positioning link
61, disposed perpendicular to shaft 26, fixes the distance between
pickup 57 and the vertical centerline of the rail as in FIG. 5.
The complete measurement cycle requires approximately 11/4 seconds.
This cycle time therefore limits the safe top speed to
approximately 12 mph while making such measurements on jointed
rails, and to approximately 25 mph while making measurements 40
feet apart on welded rails. The provisions for safe operation will
include Cycle Completion Interlocks that will prevent initiation of
another measurement cycle until the reference elements have rotated
and lifted to their standby positions. If for any reason a
measurement cycle is not completed in 11/2 seconds, an audible
Malfunction Alarm will be energized. Another safety feature of this
system is the Reverse Interlock wherein a switch attached to the
truck gear shift mechanism (not shown) will prevent measurements
while the transmission is in its reverse position. As previously
mentioned, the Digital Tachometer will provide overspeed signals to
each Sequence Controller. Two sets of internally mounted
thumbwheels are provided to preset two speeds above which
measurements will be inhibited. The thumbwheels are selected by the
Mode Selector switch; one will be typically preset at 12 mph for
the JOINT mode, and the other will be typically preset at 25 mph
for the PRESET DISTANCE mode.
It should be pointed out that the lowermost web contacting sphere
27b of reference element 27 typically bears upon a point located
above the minimum web thickness so as to minimize the possibility
of the reference element striking tie clamps, protruding spikes and
the like.
With reference to FIG. 8, it is to be noted that the distance
measuring system as described with reference to FIG. 7 will share
the output of the Optical Wheel Tachometer utilized for speed
measurement in the control system. The output of the tachometer is
360 pulses per revolution and based on 1000 revolutions per mile
will provide 68 pulses per foot of travel. Rate multiplier
thumbwheels (not shown) may be provided to permit adjustment to
compensate for wheel diameter variations. Also, the memory circuits
will be provided in the data channels for recording milepost number
and feet from the preceding milepost. This system has the
capability of counting either increasing or decreasing milepost
numbers.
It should be pointed out that the signals at A in FIG. 8 are AC
signals voltage proportional to the displacement of the wear
feelers. The signals at B are DC signals voltage proportional to A.
The signals at C represent a digital code format which is stored in
MEMORY and which is printed at D.
From the foregoing, it can be seen that a measurement system has
been devised which includes an assembly movable along a railroad
track for accurately measuring top and side rail wear in a fully
automatic and efficient manner. A printout from the data recorder
provides an accurate and permanent record of the rail wear data in
a manner not heretofore made possible.
The assembly has displacement pickups which bear upon points on a
top surface and on an inner side surface of each rail for measuring
the rail wear of those surfaces. Reference elements associated with
each pair of pickups bear upon unworn portions of the rails.
Accordingly, wear measurements are taken while the assembly moves
along the track, such measurements being made in relation to
reference rail measurements for each rail entered into the system
respecting unworn top and inner side surfaces of a reference
rail.
And, with the assembly and its frame for each rail being capable of
pivotal movement away from its associated rail, excessive wear of
the pickups are avoided since they do not contact the rails until
measurements are to be made.
Obviously, many modifications and variations of the invention are
made possible in the light of the above teachings. It is therefore
to be understood that within the scope of the appended claims the
invention may be practiced otherwise than as specifically
described.
* * * * *