United States Patent 1
`Dennyet al.
`
`ARR
`US005633628A
`[11] Patent Number:
`5,633,628
`[45] Date of Patent:
`May 27, 1997
`
`{S4] WHEELSET MONITORING SYSTEM
`
`[75]
`
`Inventors: Joseph M. Denny, Fairport; David W.
`Marcellus, Rochester. both of N.Y;
`Gordon F. Quigley. North Andover,
`Mass.
`
`[73] Assignee: General Railway Signal Corporation,
`Rochester, NVY.
`
`[21] Appl. No.: 582,535
`aaa.
`Ia] Filed:
`dam, 3. 2298
`CSG]
`Bene CL? ccesscecssrtsserecnsendenidbbiensbtacrest GOSB 21/00
`(52) US. Ch scsssssssccsssccsscsves 340/584; 340/449: 340/589;
`340/682
`[58] Field of Search wcccsuecsnen 340/584, 589,
`340/682, 449
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`oe soon Seearerseceerevemssmsasannsaes 340/682
`4.977STI 12/1990 Arthur et ab.esses
`een357,
`5,381,692
`1/1995 Winslowet al.
`...
`5,438,322
`
`8/1995 Martin et al. ou... «340/584
`
`Primary Examiner—Gien Swann
`Attorney, Agent, or Firm—Ohblandt, Greeley, Ruggiero &
`Petle
`
`[57]
`
`ABSTRACT
`
`A thermal warning device attaches to a wheel assembly of a
`railway car to detect whether the wheel assembly has
`reached high temperatures and may lead to a potential
`bearing failure. A temperature sensor for monitoring the
`temperature of the wheel assembly is coupled to an elec-
`tronic circuit for determining whether a bearing failure may
`occur based on the temperatures detected by the temperature
`sensor. In particular,
`the temperature sensor adjustably
`extends into the wheel assembly in order to obtain accurate
`readings of high temperatures in wheel assembly. Also, the
`electronic circuit is situated away from the outer surface of
`the wheel assembly so that the electronic circuit will not be
`subjected to heat from the wheel assembly and may freely
`dissipate heat produced by its own components. Upon
`determination of a warning condition, the electronic circuit
`transmits a warning signal to a waysidestation ortrain crew.
`Optionally. the electronic circuit may include a wireless
`METTRIDIGEE TO COMTIeaOR "Wid an tab meCeivet
`26 Claims, 6 Drawing Sheets
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`EX1008
`Petitioner Hum (223)
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`EX1008
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`US. Patent
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`May 27, 1997
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`Sheet 1 of 6
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`5,633,628
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`May27, 1997
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`Sheet 3 of 6
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`U.S. Patent
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`U.S. Patent
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`May27, 1997
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`Sheet 4 of 6
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`5,633,628
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`CONTROLLER
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` PROCESSOR
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`A/D
`CONVERTER
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`FIG.5
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`May 27, 1997
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`May 27, 1997
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`1
`WHEELSET MONITORING SYSTEM
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`BACKGROUND OF THE INVENTION
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`1. Field of the Invention
`
`The present invention relates generally to thermal detec-
`tion systems that detect the failure of mechanical devices
`when a predetermined temperature has been reached. More
`particulasly, the present invention relates to thermal warning
`device in a wheel assembly of a railway car to indicate when
`the temperature of the wheel assembly has reached a level
`indicative of potential bearing failure.
`2. Description of the Prior Art
`Various warning devices are used to detect impending
`trouble in a wheel assembly of a railway car before the
`actual occurrence of a bearing failure. One indicator of
`possible bearing failure is the detection of excessively high
`temperatures in the wheel assembly. In particular, overheat-
`ing of the wheel assembly may lead to an undesirable
`incident, such as a train derailment. ‘To forestall such an
`event, a thermal warning device may be positioned in a
`wheel assembly to indicate a possible bearing failure when
`the wheel assembly has exceeded a predetermined threshold
`temperature.
`Tt is known that thermal warning devices in the form of
`specially adapted bolts may be substituted for standard bolts
`that are normally secured to the wheel assembly. These
`specially adapted bolts or thermal warning bolts determine
`when a railway car bearing has reached a predetermined
`threshold temperature, and, as a consequence, provide a
`warning signal to a wayside station or train crew in time to
`prevent potential problems. For example, U.S. Pat. No.
`4,812,826 to Kaufman et at, which issued on Mar. 14, 1989,
`provides a thermal warning bolt having the dimensions of a
`standard bolt and includes a communication circuit for
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`producing a radio frequency signal that provides a warning
`signal. Responsive to the rise in temperature in the wheel
`assembly, an antenna, which is positioned axially in the bolt,
`extends through the head of the bolt. The movement of the
`antenna triggers the communication circuit to emit the radio
`frequency signal and, thus, alert a train crew of a possible
`problem with the wheel assembly.
`Oneproblem with implementing a communication circuit
`in a standard bolt is the sensitivity of its electronic compo-
`nents to heat. The temperature of the wheel assembly can
`teach levels as high as 250 degrees to 350 degrees Celsius.
`In order to function properly and reliably. such electronic
`components require a way to dissipate heat and avoid high
`temperature levels. Accordingly, high temperatures pro-
`duced by bearing assemblies may cause communication
`circuits of thermal warning bolts to malfunction.
`Another problem is the mechanical degradation ofthe bolt
`due to hollowing the bolt to accommodate the communica-
`tion circuit. An additional problem is the such bolt may be
`used only once since the communication circuit in the bolt
`only transmits when a predetermined threshold temperature
`is breached, Due to its one shot nature, there is no way to
`self-test the communication circuit to determine whether it
`is functional.
`
`In view of the above problem, thermal warning devices
`have been designed to minimize the adverse effects caused
`to the thermal sensors’ electronic components by exposure
`to high temperatures. For example. U.S. Pat. No. 5.438.322
`to I. M. Martin. et al.. which issued on Aug. 1. 1995.
`
`2
`sensorsituated at the opposite end of the bolt. The commu-
`nication circuit is positioned away from high temperatures
`while the temperature sensor is situated near the wheel
`assembly. Similar to U.S. Pat. No. 4,812,826 cited above,
`this thermal warning bolt suffers from the problems of
`mechanical degradation of the bolt and one shot operation
`which prohibits self-testing.
`In addition, U.S. patent application Ser. No. 08/276,.845 to
`J. M. Denny, et at., which wasfiled on Jul. 18, 1994 now
`abandoned, provides a thermal warning device having a
`temperature sensor situated in a bolt whereas a communi-
`cation circuit coupied to the temperature sensoris positioned
`outside of the bolt. In particular. the communication circuit
`is enclosed in a housing thatis situated adjacent to the wheel
`assembly. The communication circuit of the thermal warning
`device is positioned away from high temperatures generated
`by the wheel assembly while the temperature sensor is
`situated near the wheel assembly for accurate detection of
`high temperatures. However,similar to U.S. Pat. Nos. 4.812,
`$26 and 5,438,322 cited above, this thermal warning device
`has the problem of mechanical degradation of the bolt.
`Thermal warning devices that provide reliable detection
`of high temperatures are typically expensive and require
`extensive assembly and installation. In order to obtain an
`accurate high temperature reading of a wheel assembly, the
`temperature sensor of the thermal warning device should,
`preferably, extend deep into the wheel assembly.
`Unfortunately, the distance that a temperature sensor may
`extend into the wheel assembly varies with the type and
`configuration of the wheel assembly. Since existing thermal
`warning devices have temperature sensors with fixed
`lengths. it is costly for one to stock a variety of thermal
`warning devices, each having a different temperature sensor
`length. In addition, since existing thermal warning devices
`employ temperature sensors embeddedin one of three wheel
`assembly retaining bolts, the bolt strength is degraded by the
`creation of a bore through the boit. Additionally, bearings
`from different manufacturers operate at vastly different
`temperatures and precludes the use of a fixed threshold
`temperatures sensor. Further, a thermal warning device
`having a communicationcircuit that is positioned away from
`the wheel assembly tends to be expensive to manufacture
`andinstall.
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`Against the foregoing background,it is a primary object
`of the present invention to provide a thermal warning device
`having its electronic components positioned away from high:
`temperatures of a wheel assembly in order to minimize the
`adverse effects caused by exposure to such high tempera-
`tures.
`
`it is another object of the present invention to provide
`such a thermal warning device in which the body of the
`thermal warning device may be inserted into a threaded hole
`created on one side of the wheel assembly without mechani-
`cal degradation of the wheel assembly.
`itis further object of the present invention to provide such
`a thermal warning device which includes a temperature
`sensor that extends deep into the areas near wheel assembly
`in order to obtain accurate readings of high temperatures in
`wheel assembly.
`It is a still further object of the present invention to
`provide such a thermal warning device in which the tem-
`perature sensor is variable in length to adjust to the inner
`portion of the wheel assembly.
`Tt is a still another obiect of the present invention to
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`5,633,628
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`ated a particular distance away from the outer surface of the
`wheel assembly.
`It is a still further object of the present invention to
`eliminate the need for drilling a bore into a support bolt of
`the wheel assembly.
`It is a still further object of the present invention to
`eliminate the requirement of wheel shops or disassembly of
`the wheel assembly to replace old or damaged communica-
`tion circuits.
`
`It is a further object of the present invention optionally to
`include a radio transmitter, such as a spread spectrum
`transmitter, as means for communicating wireless signals
`from a variety of warning devices to respective receivers.
`It is a yet another object of the present invention to
`provide such a thermal warning device that is inexpensive
`and simple to manufacture andinstall.
`It is a still another object of the present invention to
`provide such a thermal warning device that has customized
`threshold temperature levels for different wheel assembly
`types and self-test diagnostic capability.
`SUMMARY OF THE INVENTION
`
`10
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`20
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`4
`portion of the housing separatesthe third circuit portion of
`the housing from the wheel assembly so that a substantial
`gap of thermal insulation is created between the electronic
`circuit and the wheel assembly.
`Another aspect of the present invention resides in the
`inclusion of a wireless transmitter for communication of
`wireless signals from a variety of warning devices to respec-
`tive receivers.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The foregoing andstill further the objects and advantages
`of the present invention will be more apparent from the
`following detailed explanation of the preferred embodi-
`ments ofthe invention in connection with the accompanying
`drawings:
`FIG. 1 is a perspective view of a preferred embodimentof
`the present invention;
`FIG. 2 is a side elevational view of the preferred embodi-
`ment of FIG. 1;
`FIG.3 is an exploded view of the preferred embodiment
`of FIG. 1;
`FIG.4 is a sectional view along line 44 ofthepreferred
`embodiment of FIG. 1;
`FIG. 5 is another top view of the body of the preferred
`embodiment FIG. 4 in which the electronic circuit and
`batteries are positioned in the body;
`FIG. 6 is a diagrammatic view of the electronic compo-
`nents of the preferred embodiment of FIG. 1; and
`FIG. 7 is a perspective of the preferred embodiment of
`FIG.1, a locking plate and a wheel assembly.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`To accomplish the foregoing objects and advantages, the
`primary feature of the present invention, in brief summary,
`is a thermal warning device for detection of a potential
`bearing failure in a wheel assembly which comprises a
`housing having a first insert portion for insertion into the
`wheel assembly. The first insert portion includes a bore,
`which extends through thefirst insert portion, having a distal
`end. In addition, a temperature sensor, responsive to an
`elevated temperature indicative of the potential bearing
`failure, is adjustably positioned throughthedistal end ofthe
`bore such that at least a portion of the temperature sensor is
`external to the bore. Accordingly, the temperature sensor
`adjustably slides through the distal end of the bore to adjust
`Referring to the drawings and, in particular. to FIG. 1,
`to inner dimensions of the wheel assemblyasthefirst insert
`there is provided a thermal warning device ofthe preferred
`portion is inserted into the wheel assembly.
`embodiment which is generally represented by reference
`More specifically,
`the primary feature of the present
`numeral 10. The thermal warning device 10 is designed to
`invention is a thermal warning device for detection of a
`monitor the conditions of bearing assemblies of railway car
`potential bearing failure in a wheel assembly which com-
`wheels. One or more of the devices 10 may be placed in a
`prises a housing havingafirst insert portion for insertion into
`single wheel assembly, including a bearing assembly and
`the wheel assembly. The first insertion portion includes a
`axle, and extend into the axle of the wheel assembly. For
`bore, which extends through the first insert portion, having
`example,
`the device 10 may be positioned in a wheel
`a first end and a second end. In addition, a temperature
`assembly by creating a threaded hole on one side of the
`sensor, responsive to an elevated temperature indicative of
`wheel assembly and screw mounting the device into the
`the potential bearing failure, having a baseat one end and a
`threaded hole.
`tip at an opposite end, is adjustably positioned through the
`first end of the bore such that the base is within the bore
`whereas the tip is external to the bore. Accordingly, the
`temperature sensor adjustably slides through thefirst end of
`the bore to adjust to inner dimensions of the wheel assembly
`as the first insert portion is inserted into the wheel assembly.
`Further, the present invention is a thermal warning device
`for detection of a potential bearing failure in a wheel
`assembly which comprises a housing having a first insert
`portion, a second separating portion and a third circuit
`portion. The second separating portion of the housing has a
`shoulder positioned adjacent to the wheel assembly and a
`connecting section distal from the shoulder. The third circuit
`portion of the housing is integrally attached to the connect-
`ing section of the second separating portion, the third circuit
`portion having a planar surface directed toward the wheel
`assembly that is distal from the wheel assembly at a prede-
`termined distance. In addition, an electronic circuit located
`Whe Hie, hte theta: Medel ele oe elects
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`As shown in FIG. 1, the preferred embodiment of the
`thermal warning device 10 is a one piece, modular unit
`comprising a housing 12 having a threaded lowerportion 14
`and a temperature sensor 16 extending from the lower
`portion. The default position of the temperature sensor 16 is
`to be fully extended from the lower portion 14 of the housing
`12 as shown in FIG. 1. As the device 10 is screw mounted
`into the wheel assembly, the temperature sensor 16 will
`remain fully extended until obstructed by a wall or structure
`in the wheel assembly. Thus, the distance that the tempera-
`ture sensor 16 extends from the lower portion 14 of the
`housing 12 is adjustable based on the amount of space
`available in the wheel assembly. Accordingly, the device 10
`is designed to accommodateall sizes and types of wheels for
`installation and beeasily replaced for maintenance purposes.
`Referring to FIG.2, the housing 12 ofthe thermal warning
`device 10 includes three generally cylindrical portions: an
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`18 has a cap 24 that covers the inner components of the
`device 10. Although the cap 24 may be removable for easy
`inspection and access by maintenance personnel, it is pre-
`ferred that an ultrasonic weld 26 secures the cap 24 to the
`test of the housing 12 to provide a hermetic seal, strong
`tensile strength and high impactresistance. Also, the circuit
`portion 18 has a lower, planar surface 28 located on the side
`opposite the removable cap 24 of the circuit portion.
`The intermediate separating portion 20 has a connecting
`section 30 that is integrally and centrally attached to the
`lower, planar surface 28 of the upper circuit portion 18. The
`separating portion 20 also has a shoulder 32 at its lower side
`that is positioned adjacent to the outer surface of the wheel
`assembly whenthe device 10 is positioned therein. Also, the
`sectional diameter 34 of the separating portion 20 is sub-
`stantially smaller than the sectional diameter 36 of the upper
`circuit portion 18, and the axial thickness 38 of the sepa-
`rating portion is such that the connecting section 30 is distal
`from the shoulder 32. Therefore, when the device 10 is
`positioned in the wheel assembly, a layer of air exists
`beneath the lower, planar surface 28 of the circuit portion 18.
`thereby creating a substantial gap of thermal insulation
`between the circuit portion and the wheel assembly. A
`potting compound may be positioned beneath the lower,
`planar surface 28.
`Whenthe device 10 is in position for use, the lower insert
`portion 22 of the housing 12 is inserted into the wheel
`assembly whereas the circuit portion 18 and the separating
`portion 20 remain on the outside of the wheel assembly. As
`shown in FIG.2, the insert portion 22 has a threaded outer
`surface 40 for screw mounting in the wheel assembly. In
`effect, the combination of the insert portion 22 with the
`separating portion 20 includes dimensionsthat are similar to
`that of a standard bolt.
`
`Referring to FIG.3, the inner compartmentof the housing
`12 supports an electronic circuit 42. a power supply 44 and
`a probe assembly 46. In addition, a pair of insulated lines 48
`couples the temperature sensor 16 of the probe assembly 46
`with the electronic circuit 42. For the preferred embodiment,
`the electronic circuit 42 includes a circuit board 50 having
`a support strip 52 at each ofits four sides to secure the circuit
`board in the housing 12 and protect the circuit board from
`erratic movements subjected to the device 10 by its hazard-
`ous environment.A silicon potting compound may be used
`in place of the support strip 52. Also, the power supply 44
`for the preferred embodiment is a pair of batteries, such
`Lithium cell batteries.
`
`Referring to FIG. 4, the various componentsof the device
`10 are supported by the housing 12 such that the electronic
`circuit 42 and the power supply 44 are positioned at the
`upper most position and the temperature sensor 16 is posi-
`tioned at the lower most position. The electronic circuit 42
`and the power supply 44 are supported in the circuit portion
`18 of the housing 12 by a plurality of support railings 54
`extending from the inner walls of the circuit portion 18 to
`provide mechanical strength.
`Asshownin FIG. 4, the probe assembly 46 of the device
`10 is supported within a bore 56 extending through the insert
`portion 22 of the housing 12. The bore 56 is substantially
`even throughoutits entire length except for its ends. A distal
`end 58 of the bore 56 has a narrower cross-section than the
`test of the bore, and a non-distal end 60 of the bore has a
`wider cross-section that the rest of the bore.
`The probe assembly 46 includes the temperature sensor
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`6
`shownin FIG. 4). The body 62 of the temperature sensor 16
`is substantially cylindrical in shape. The temperature sensor
`16 has a half-spherical tip 64 at one end and a base 66 having
`an enlarged diameterat the other end. Thus, the temperature
`sensor 16 is designed for sliding movement through the
`distal end 58 of the bore 56 such that the base 6@ of the
`temperature sensor 16 is supported by the inner wall of the
`bore and the body 62 of the temperature sensor is supported
`by the distal end.
`Aplug 68 is positioned in the non-distal end 60 of the bore
`56 to seal the bore from the remainder of the inner com-
`partmentof the housing 12 with the exception of the pair of
`insulated lines 48. In addition, a spring mechanism 70 is
`positioned between the plug 68 and the base 66 of the
`temperature sensor 16. As shown in FIG. 4, the plug 68
`permits the pair of insulated lines 48 to pass through so that
`the lines couple the temperature sensor 16 to the electronic
`circuit 42. For the preferred embodiment, the plug 68 is
`secured by an ultrasonic weld that provides a hermetic seal.
`The plug 68 must be strong enoughtoresist the spring force
`of the spring mechanism 70. Accordingly, the ultrasonic
`weld of the preferred embodimentis strong enough to resist
`a spring force of about 150 lbs.
`Accordingly, the temperature sensor 16 moves axially
`through the distal end 58 of the bore 56. The movement of
`the base 66 of the temperature sensor 16is restricted to the
`area between the distal end 58 and non-distal end 60 of the
`bore 56. At its default position shownin FIG. 4, the base 66
`of the temperature sensor 16 is held against an abutting
`shoulder 72 at the distal end 58 by an axial force exerted by
`the spring mechanism 70. As the device 10 is inserted into
`the wheel assembly, an inner portion of the wheel assembly
`may contact the tip 64 of the temperature sensor 16 and force
`the temperature sensor against the spring mechanism 79.
`Thus, if the inner portion of the wheel assembly cannot
`accommodate the full length of the temperature sensor 16,
`the temperature sensor will adjust to the appropriate length.
`With the spring-loaded temperature sensor 16, the device 10
`fits all wheel assembly sizes, including 50 ton. 75 ton, 100
`ton and 125 ton bearing assemblies. Accordingly, the tem-
`perature sensor 16 reads axle temperature and adjusts to the
`varying sizes of wheel assemblies, in general, including the
`bearing assembly and axle sizes.
`Referring to FIG. 5, the electronic circuit 42 of the
`preferred embodiment includes a circuit board 50 and a
`power supply 44 interconnected to the circuit board. The
`circuit board 50 may provide the device 10 with a wide
`variety of functions. For example. the elementsof the circuit
`board 50 may measure the effects of temperature, vibration
`and acceleration that have been detected by the device 10.
`Also, the device 10 may determine whether the wheelset
`becomesloose, determine whether communication circuitry
`is operating properly and continuously. perform periodic
`monitoring and self tests, control monitor rate in order to
`extend battery life, compare ambient temperature against
`measured temperature and producerate of rise comparisons,
`and determine whether the temperature sensor 16 is properly
`positioned in the center of the wheel assembly.
`Referring to FIGS. 5 and 6, the circuit board 50 of the
`preferred embodiment includes a analog-to-digital converter
`74, a microprocessor controller 76, an on-board wireless
`transmitter 78 and a on-board temperature sensor 80.
`Although not shown in FIG. 5, the electronic circuit 50 may
`also include an antenna 86, such as a wire helix, that is
`soldered to the on-board transmitter 78. During operation,
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`temperature sensor 16 or acceleration readings from an
`accelerometer 82, and convert them to digital form for
`processing by the microprocessor controller 76. The micro-
`processor controller 76 then determines whether potential
`bearing failure may occur in the wheel assembly.If potential
`bearing failure may occur, the microprocessor controller 76
`will instruct the on-board transmitter 78 to send a warning
`signal to receivers 84 located within the transmitting range
`of the on-board transmitter. Such receivers may be located
`on-board a railway train cab or at a wayside station.
`The analog-to-digital converter 74 may also receive ambi-
`ent temperature readings from the on-board temperature
`sensor 80. In such case, the microprocessor controller 76
`may perform a rate of rise comparison to track the rate of
`temperature change of the bearing temperature readings. An
`important feature of the present invention is that the elec-
`troniccircuit 50 is alwaysactive as it monitors all conditions
`surrounding the device 10 andall internal conditions of the
`device, analyzes such conditions and transmits the results of
`its analysis to a receiver 84 within transmitting range.
`As noted previously, the wireless transmitter 78 commu-
`nicates with the in-cab receiver $4 or the like. Preferably, the
`transmitter would be a spread spectrum transmitter utilized
`to exploit its known advantages of relative freedom from
`interference by other transmitters, and its ability to transmit
`discrete address components as part of the modulatedsignal,
`whereby independent faults at particular locations can be
`individually identified and displayed by utilizing separate
`transmitters at the respective locations which communicate
`with corresponding receivers.
`The wireless transmitter would preferably be a spread
`spectrum transmitter, for example, as disclosed in U.S. Pat.
`No. 4,977,577, which issued on Dec. 11, 1990, entitled
`WIRELESS ALARM SYSTEM. The disclosure of that
`transmitter of U.S. Pat. No. 4,977,577 is incorporated herein
`by reference, particularly as to its address means, function-
`ing to provide a unique addressfor selective reception by a
`corresponding receiver.
`Referring to FIG. 7, the preferred device 10 is supported
`against the outer surface of the wheel assembly 88 by a
`locking plate 90. The locking plate 90 includes a plurality of
`prongsor tines 92 that may bend inward toward the device
`10 or outward toward the wheel assembly 88. The device 10
`is positioned against the outer surface of the wheel assembly
`88 with its temperature probe 16 extending into a receiving
`hole 94 of the wheel assembly. Also, the locking plate 90
`positioned between the device 10 and the outer surface of the
`wheel assembly 88. The device 10 may be mountedinto the
`receiving hole 94 by grabbingthe outer circumferenceof the
`housing 12 is a tie wrap or engaging a central aperture 96 of
`the cap 24 with a standard socket wrench. To secure the
`device 10 to the locking plate 90, several of the tines 92 are
`bent inward into grooved portions 99 at the lower, planar
`surface 28 of the housing 12. Although grooved portions 98
`are not shown in FIGS. 1 through4.it is to be understood
`that such grooves may be molded or otherwise formed at the
`lower, planar surface 28 of the housing 12. Similarly, to
`secure the locking plate 90 to the wheel assembly 88. other
`tines 92 are bent outward around support bolts 98 at the
`outer surface of the wheel assembly. In particular, tines 92
`are positioned on both sides of each support bolt 98 to
`preventthe locking plate 90 from rotating. Accordingly,the
`device 10 may be rotated only when the tines 92 have be
`bent back to their original positions away from the support
`bolts 98.
`The inwantinn having heen thic dacerthed unth nartioular
`
`8
`that various changes and modifications may be made therein
`without departing from the spirit and scope ofthe invention
`as defined in the appended claims.
`Wherefore, we claim:
`1. A thermal warning device for detection of a potential
`bearing failure in a wheel assembly comprising:
`a housing having an insert portion for insertion into the
`wheel assembly;
`a bore extending through said insert portion, said bore
`having a distal end; and
`a temperature sensor, responsive to an elevated tempera-
`ture indicative of the potential bearing failure, said
`temperature sensor being adjustably positioned through
`said distal end of said bore such that at least a portion
`of said temperature sensor is external to said bore;
`wherein said temperature sensor adjustably slides through
`said distal end of said bore to adjust to inner dimensions
`of the wheel assembly as said insert portion is inserted
`into the wheel assembly.
`2. The thermal warning device of claim 1, wherein said
`insert portion has a threaded outer surface for screw mount~
`ing in the wheel assembly.
`3. The thermal warning device of claim 1, wherein said
`temperature sensor includes a base at an end portion ofsaid
`temperature sensor.
`4. The thermal warning device of claim 3, further com-
`prising a distal shoulder at said distal end of said bore for
`preventing said baseof said temperature sensor from passing
`through said distal end.
`5. The thermal warning device of claim 3, further com-
`prising a plug positioned at a non-distal end of said bore for
`preventing said baseof said temperature sensor from passing
`through said non-distal end.
`6. The thermal warning device of claim 1, further com-
`prising a spring positioned in said bore for applying an
`outward axial force to said temperature probe and counter-
`ing an inward axial force from said temperature probe.
`7. The thermal warning device of claim 1, further com-
`prising an electronic circuit positioned in said housing and
`coupled to said temperature probe, said electronic circuit
`including a controller for determining whether the potential
`bearing failure may occur.
`8. The thermal warning device of claim 7, wherein said
`electronic circuit includes an antenna and a transmitter for
`transmitting a warning signal to receivers located within a
`particular transmitting range.
`9. The thermal warning device of claim 1, wherein:
`said temperature sensor detects temperature readings cor-
`responding to temperatures in the wheel assembly;
`said housing includes a second temperature sensor for
`detecting second temperature readings corresponding
`to temperatures outside of the wheel assembly; and
`said housing includes an electronic circuit coupled to said
`temperature sensor and said second temperature sensor
`for determining a rate of temperature change of said
`temperature reading based on said second temperature
`reading.
`10. The thermal warning device of claim 9, wherein said
`second temperature sensor is located on said electronic
`circuit.
`11. The thermal warning device of claim 1, further com-
`prising an electronic circuit positioned in said housing, said
`electronic circuit including a spread spectrum transmitter for
`transmitting a modulated signal having discrete address
`components.
`AD A tHharmal wraentn ne Aneta fae dese nttn Af - 4 att
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`10
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`5,633,628
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`9
`a housing having an insert portion for insertion into the
`wheel assembly;
`a bore extending through said insert portion, said bore
`having a first end and a second end; and
`a temperature sensor, responsive to an elevated tempera-
`ture indicative of the potential bearing failure. having a
`base at one end and a tip at an opposite end, said
`temperature sensor being adjustably positioned through
`said first end of said bore such that said base is within
`said bore whereas said tip is external to said bore;
`wherein said temperature sensor adjustably slides through
`said first end of said bore to adjust to inner dimensions
`of the wheel assembly as said insert portion is inserted
`into the wheel assembly.
`13. The thermal warning device of claim 12, wherein said
`insert portion has a threaded outer surface for screw mount-
`ing in the wheel assembly.
`14. The thermal warning device of claim 12, further
`comprising a distal shoulderat said first end of said bore for
`preventing said base of said temperature sensor from passing
`through said first end.
`15. The thermal warning device of claim 12, further
`comprising a plug positioned at said second end ofsaid bore
`for preventing said base of said temperature sensor from
`passing through said second end.
`16. The thermal warning device of claim 12, further
`comprising a spring positioned in said bore for applying an
`outward axial force to said base of said temperature sensor
`and countering an inward axial force from said base of said
`temperature sensor.
`17. The thermal warning device of claim 12. further
`comprising an electronic circuit positioned in said housing
`and coupled to sai