US2420968A - Hot journal alarm apparatus - Google Patents

Description

May 20, 1947. G, Kr NEWELL HOT JOURNAL ALARM APPARATUS Filed March 30, 1944 2 Sheets-Sheet 1 IN1/Emol:V GEORGE K. NEWELL.

ATTORNEY May 20, 1947.

G. K. NEWELL HOT JOURNAL ALARM APPARATUS Filed March 30, 1944 2 Sheets-Sheet 2 Inf-76 x INVENTOR GEORGE K. NEWE'LL.

A TI'ORNE Y Patented May 20, 1947 UNITED STATES PATENT OFFICE HOT JOURNAL ALARM APPARATUS Application March 30, 1944, Serial No. 528,710

2 Claims.

This invention relates to hot journal alarm apparatus, that is, apparatus for giving a signal or an alarm whenever a bearing or journal approaches an abnormally hot condition, and has particular relation to hot journal alarm apparatus for railway cars and trains.

The railroads have long sought a simple and inexpensive apparatus for apprising the engineer or crew of a train of the occurrence of a hot box or hot axle journal on any of the cars of the train because hot boxes not only damage the parts of the journals but may even result in breakage of an axle and possible wreckage of the train due to derailment of a car following breakage of the axle.

Various devices and apparatus have been proposed and employed for the purpose of signaling the occurrence of a hot box on railway cars and trains. Such devices and apparatus variously empl-oy different types of thermal-responsive elements, such as fusible elements, bfi-metallic elements, gas-chambers, or thermo-couples.

It is an object of my present invention to provide a novel means for registering the heat condition in a bearing or journal, such as the axle journal of a railway car.

More particularly, it is an object of my invention to provide a Wheatstone bridge arrangement including resistance elements of relatively high temperature coeii'cient of resistance; and to dispose the resistance elements in a manner to be responsive to the heat condition of a plurality of journals, whereby to attain an unbalanced condition of the bridge when an abnormal heat condition of one journal with respect to the heat condition o-f another journal occurs.

It is another object of my invention to provide apparatus of the nature indicated in the foregoing objects characterized, however, in that some of the resistance elements of the Wheatstone bridge are exposed to ambient temperature or heat conditions as distinguished from the heat condition of a journal.

It is another object of my invention to provide apparatus of the nature indicated in the foregoing objects and further characterized by means, responsive to the travel of the car or train equipped with the apparatus, for intermittently rendering the apparatus eiective, thereby conserving the amount of electrical energy required to operate the apparatus.

The above objects, and other objects of my invention which will be made apparent hereinafter, are attained by embodiments subsequently to be described and illustrated in the accompanying drawings, wherein Fig. 1 is a diagrammatic view showing one embodiment of my invention, as applied to a pair of axle journals of a railway car truck.

Fig. 2 is a simplified schematic electrical wiring 2 diagram corresponding to the apparatus shown in Fig. 1, and

Fig. 3 is a fragmental sectional view showing the form of cartridge or unit which may be employed to contain several of the resistance elements of the Wheatstone bridge arrangement arranged for exposure to ambient temperature. The device shown in Fig. 3 is to be considered as joined to apparatus shown in Fig. 1 at the line marked .r--x in substitution for a part of the apparatus shown in Fig. 1.

Description Referring to Fig. 1, there is shown a railway car wheel axle II broken at the middle and having similar roller bearing journal casings I2 at opposite ends thereof. In each of the journal casings I2 at a point outside the bearing races is a bore I3, in substantially parallel relation to the axle I I, forming a heat well, the heat in which is indicative of the heat in the journal. The bores I3 are lined with suitable insulating material I4 to prevent grounding of parts of a thermal-responsive device received therein and hereinafter referred to as a resistance cartridge or unit I5.

Each resistance cartridge or unit I5 comprises a screw plug Il that is screwed into the outer threaded end 0f the bore I3 receiving it and is enclosed by an end cover I6 that is removably 30 secured to the journal casing. Two concentric tubular members I8 and I9 of insulating material are secured to screw plug I'l and extend generally in parallel relation to the axle I I. Wound on and secured to the outer tubular member I8 and the inner tubular member I9 are resistance elements or coils of resistance wire, such as iron wire, having a relatively high temperature coecient of resistance (.005 for iron wire).

The four resistance elements in the two cartridges are designated respectively as RI, R2, R3, and R4.

As shown in Fig. 1, resistance elements RI and R3 are disposed on the outer and inner tubular members I8 and I9 respectively of cartridge I5 45 associated with the left-hand journal. The resistance elements R2 and R4 are disposed on the outer and inner tubular members I8 and I9 of the cartridge I5 associated with the right-hand journal.

50 Resistance elements RI, R2, R3, and R4 are connected in a Wheatstone bridge arrangement as shown in Fig. 2. Suitable wires, hereinafter identied, are connected to opposite ends of each resistance element respectively, making a total of 55 four Wires connected to each cartridge unit I5. The screw plug I1 of each cartridge is provided with suitable openings through which these lead wires extend, in insulated relation to the resistance elements.

ExternaI circuit connections are made to the resistance elements by means of suitable electric coupling devices or plugs 2l having contact prongs 22 that telescope in suitable sleeve contacts 23 carried in an insulating bushing 24 supported in the end cover I6. Suitable means, not shown, but similar to that employed on radio tubes, is provided for insuring proper connections through the coupling devices at all times.

As in the case of any Wheatstone bridge, a suitable source of current, illustrated as a storage battery 26, is provided. In the case of a train of cars an individual battery 26 is provided for each car, which battery may be the usual car lighting battery.

For the purpose of conserving the energy required from the battery 26, I have provided an intermittently operative switch device 21 for momentarlly connecting the battery 26 to the Wheatstone bridge circuit at intervals.

The switch device 21 may coirprise a separable casing 28 attached to a part of the car, such as the car truck, which is subject to pronounced road shock. As diagrammatically shown, switch device 21 may further comprise a contact arm 29 p-ivotcd at one end, as by a pin 3l, to a boss 32 on the interior of the casing 28 and supported at the opposite end by a coil spring 33 interposed between the end thereof and the lower wall of the casing 29. For the purpose of imparting a pronounced inertia characteristic to the contact arm 29, a suitable weight 35 is secured thereto.

The contact arm 26 has an intermediate portion insulated entirely from the casing 28, which portion carries a contact 36 for cooperation with a spring-biased contact 31 supzorted in a recess 36 in the casing 28 at point below the arm 29.

The contact 31 is carried on the end of a pin 39 having a collar 49 thereon which is guided in an insulating bushing 4l lining the recess 38. The lower end of the pin 39 is gui-ded in an insulating bushing 42 lining the lower portion of the recess 38 of reduced diameter.

An electrical connection is made to the pin 39 by means of a wire 43 connected to a small metallic disk 44 at the base of the recess 38 and in insulated relation to the casing 28, a coil spring 45 being interposed between the disk 44 and the lower end of the pin 39. A constant electrical connection is thus made to the pin and contact 31, notwithstanding the oscillatory movement of the pin 39, without flexing the wire 43 and causing breakage thereof.

An insulated wire 46 extends through a suitable opening or bushing in the casing 28 and is connected to the intermediate or insulated portion of contact arm 29.

It will thus be seen that when the contact arm 29 is driven downwardly by the inertia of the weight 35 in response to road shock, contacts 36 and 31 become engaged and thereby complete a circuit from the wire 43 to the 'wire 46. Upon termination of the shock which will be of momentar-y extent. the spring 33 restores the arm 29 upwardly and separates the contacts 36 and 31. Assuming that a suiicient road shock is imparted to the weight 35 each time a car wheel passes over a rail joint, it will be seen that the frequency of engagement of the contacts 36 and 31 will be relatively high but that the length of time that the contacts 36 and 31 are engaged relative to the total travel time of the train will be relatively small.

Forthe purpose of registering the balanced or unbalanced condition of the Wheatstone bridge arrangement, I have provided a two-winding alternating-current type of relay 48. As diagrammatically shown in Fig. l, the relay 48 comprises two windings, designated a and b respectively, and two front contacts c and d respectively. The winding a is the pickup winding and is connected into the Wheatstone bridge circuit in the manner hereinafter to be described so as to be responsive to a predetermined unbalanced voltage condition thereof in a manner to actuate the iront contacts c and d from their normally dropped-out or open position to their picked-up o1' closed position.

The winding l2 of the relay 43 is a holding or stick winding, the energizing circuit for which is established over the irontcontact c which serves as a self-holding contact.

A normally closed reset switch 49 which may be of the push-button type as shown, is provided in the circuit of the holding winding b of relay 43 and is effective when opened to interrupt the circuit for the holding winding and thereby effect restoration of the relay 48 to its droppedcut position.

The character of the relay 48 is such that contacts c and d are actuated to their picked-up positions in response to energization of the pickup winding a by a current exceeding a certain value and flowing in either direction through the winding, for a reason hereinafter explained.

The contact d of the relay 48 controls a circuit for energizing a plurality of signal devices, illustrated as an alarm bell 49, a signal lamp 56, and a magnet valve 5I. The magnet valve 5l may be of any suitable type effective upon energization of the winding thereof to vent iluid under pressure from a device to be controlled, such as the brake pipe 52 on the train, to initiate brake application.

As indicated in Fig. 1 and Fig. 2, the contact d of the relay 48 is also effective to energize other signal devices, illustrated as an alarm bell 49a and signal lamp 56a disposed in the cab of the locomotive or power car of the train.

Operation In order to describe the operation of the apparatus let it be assumed that a train including a locomotive, car A, and car B, as indicated in Fig. l, is traveling along the road and that the axle journals have attained their normal operating temperatures. Let it now also be assumed that the intermittently operative switch device 21 is operated and that the contacts 36 and 31 thereof are engaged. In such case, the battery 26 is connected to the Wheatstone bridge circuit and a flow of current occurs therein. Referring to Fig. l the Wheatstone bridge circuit may be traced from the positive terminal of the battery 26 by way of a wire 54, wire 43y contacts 31 and 36 of the switch device 21, contact arm 29, wire 46, to a bus wire 55 local to car A, where the circuit divides into two parallel branches; one of the branches extending by way of a wire 6I, resistance element Rl, wire 62, resistance element R4, wire 63, to a bus wire 56 local to car A that is connected by a branch wire 65 to the negative and grounded terminal of the battery 26, the other branch extending from the bus wire 55 by way of a wire 66, resistance element R2, wire 61, resistance element R3, and a wire 68 to the bus wire 56, and thence by way of the branch wire 65 to the negative terminal of the battery 26. This circuit will be more readily apparent in Fig. 2.

If the respective temperatures of the two axle journals are substantially the same, as they will be if operating at their normal temperatures, the Wheatstone bridge wil1 be in a balanced condition. In such case, therefore, no current or substantially no current will flow through the pickup winding a of the relay 48 because no unbalanced voltage is impressed on the pick-up winding that is connected across the wires 62 and 61.

As long as both axle journals remain at normal operating temperature, the relay 48 will remain dropped-out notwithstanding the frequent establishment of the flow of current in the Wheatstone bridge by the operation of the switch device 21.

If, however, one of the axle journals such as the left-hand journal in Fig. l, starts to heat-up and reaches or approaches a temperature which may cause damage to the parts of the journal, the increased resistance of the resistance elements Rl and R3 produces an unbalanced voltage condition in the Wheatstone bridge upon connection of the battery 26 thereto by operation of the switch device 21. It will be apparent that by reason of the arrangement of the two resistance elements Rl and R3 in the Wheatstone bridge and their disposition in the same heat detector cartridge I5, a maximum unbalance of the bridge circuit is attained for a given rise in temperature of the axle journal affected. In other words, by exposing two of the resistance elements, such as Rl and R3, to the same variation of temperature or heat condition, twice the amount of unbalanced voltage is created across the terminals of the pick-up winding a of the relay 48 as would be the case if only one resistance element such as the resistance element RI were eiTected by the equivalent temperature or heat change. This specic arrangement is accordingly one of the particular features of my invention by reason of the sensitivity it imparts in the apparatus to temperature changes in the axle journals.

The resistance of the resistance elements RI, R2, R3, and R4 when cold is preferably of uniform value and is so selected, with respect to the voltage of the battery 26 impressed on the Wheatstone bridge circuit, as to provide a suilicient voltage-drop across the pick-up winding a of relay 48 to cause actuation of the contacts of the relay to their picked-up position only after the temperature in one of the axle journals rises a predetermined amount above the normal operating temperature thereof as exemplied by the temperature of the unaiected journal. The exact degree of temperature rise above normal operating temperature of the axle journal at which the pick-up of the relay 48 is effected may be any desired amount dependent upon the degree of safety factor desired. It should be so selected, however, as to be sufiiciently below the danger point at which severe damage may occur so as to provide adequate time for a train to be brought to a stop and suitable measures taken to restore the temperature of the affected journal to normal and to prevent recurrence of the abnormal heat condition.

Once the contacts of the relay 48 are picked-up, they are thereafter maintained in their picked-up position by the action of the holding winding b, the energizing circuit for which is established upon closure of the contact c. The circuit for energizing the holding winding b of relay 48 may be traced from the positive terminal of the battery 26 by way of the Wire 54, a bus wire 51 local to car A, a wire 1| including the contact c of relay 48, holding winding b, and the reset switch 49m in series relation therein, and bus Wire 56 and wire 65 to the negative terminal of the battery 26.

Contact d of the relay 48 is effective, when closed, to establish a circuit for energizing and causing actuation of the alarm bell 49, the signal lamp 58, and the magnet winding of the magnet valve 5| on car A, as well as the alarm bell 49a and the signal lamp 50a in the cab on the locomotive. the positive terminal -of the battery 26 by way of the wire 54, bus wire 51, branch wire 1|, a branch wire 13, contact d of relay 48, a wire 14, thence in parallel through the operating winding of the alarm bell 49, signal lamp 58, and the magnet winding of the magnet valve 5| to a wire 15, which is in turn connected to the negative terminal of the battery 25 by way of the bus wire 56 and wire 65. This circuit also extends from the contact d of relay 48 by way of the wire 14, a branch wire 16 including an asymmetric device 16x, such as a dry disk or tube type of rectifier, to a train wire 11, thence to the locomotive and by way of a branch wire 18, in parallel through the operating winding of the alarm bell 49a and signal lamp 50a to a wire 19 which is connected to the negative terminal of the battery 26 as through a ground connection in the manner shown. It will thus be seen that upon the pick-up of the relay 48 due to an abnormal rise of temperature in one of the axle journals, various signal devices on the individual car are actuated as well as those on the locomotive.

As previously indicated, energization of the winding of the magnet valve 5| causes a reduction of the pressure in the brake pipe 52 resulting in an automatic application of the brakes on the train, thereby forcing the engineer to shut off the propulsion power and bring the train to a stop at once. If desired, the magnet valve 5| may be omitted, in which case the automatic application of the brakes on the train in response to pick-up of the relay 48 is not effected.

The arrangement of the asymmetric devices 16x is such as to permit the How of current from a battery on a car to the train wire 11 but to prevent the reverse flow of current from the train wire to the signal devices on a car from the train wire. It will thus be apparent that when the train wire 11 is energized by flow of current therein due to pick-up of the relay 48 on one car, such as car A, the signal devices 49, 50, and 5| on another car, such as car B, are not affected because current cannot flow from the train wire 11 past the rectifier or asymmetric device 16a: on car B to those signal devices on car B,

I have previously disclosed and claimed this general arrangement for causing a signal to be simultaneously produced on a car having a hot journal and on the locomotive while preventing the actuation of signal devices on cars not having a hot journal in my prior copending application, Serial No. 528,709, led March 30, 1944, and assigned to the assignee of the present application. I accordingly make no claim to this feature in the present application.

In order to cause termination of the audible and visible signals on the cars and on the locomotive, the engineer and crew of a train will not intentionally disregard the occurrence of a hot box condition on any car of the train since it is a clear indication of their neglect to take the necessary steps to alleviate the condition. In the present instance, let it now be assumed that due to the automatic application of the brakes This circuit may be traced from y effected by operation of the magnet valve 5| or, in the absence of the magnet valve 5l, due to the application of the brakes on the train initiated by the engineer on the locomotive, upon receipt of a signal, the train is brought to a stop and the necessary measures taken to alleviate the hot box condition.

It is desirable that it be mandatory, on the part of the engineer or some member of the train crew, to take some positive steps toward alleviation of the hot box condition in order to cause termination of the audible and visible signal on the car and on the locomotive. Such an arrangement is disclosed and claimed in my prior copending application above mentioned. In the present application, I have indicated a so-called reset switch 49x in the circuit of the holding winding b of the relay 48. Although not s shown in the drawings, switch 49.7: is preferably located at a point which cannot be reached unless a positive step is taken toward alleviation of the hot box condition, such as on the interior of the end cover I6 of the axle journal casing. I have, for simplicity, not indicated such a location for the reset switch 49x, but it will be understood that in accordance with the principles taught in my prior copending application above mentioned, such location of the reset switch 49a: may be selected.

It will be apparent, therefore, that in Order to operate the reset switch 49a: to open position, it will be necessary to remove the end cover I6, thereby automatically insuring that a positive step will be taken toward alleviation of the hot box condition.

Upon opening of the reset switch 49:12, the holding winding b of the relay is deenergized and, in the absence of any energization of the pick-up winding o of the relay 48, as presently explained, the relay will be restored to its dropped-out position. thereby interrupting the circuit for energizing the signal devices on the cars on the locomotive.

It will be seen that with the train stopped, the switch 2l will remain in open position, thus disconnecting the battery 2E from the Wheatstone bridge circuit. Consequently there will be no voltage available to piek-up the relay 48. Consumption of energy from battery 26 will thus be conserved. operation of the reset switch 49x to its open position results in restoration of the relay 48 to its dropped-out position.

It should be apparent that by reason of the non-directional characteristic of the pick-up winding of relay 48, the relay 48 will be pickedup in response to the occurrence of an abnormal heat condition in eithel` of the axle journals. In the case of an abnormal heat condition occurring in the right-hand journal, therefore, notwithstanding the fact that the polarity of the unbalanced voltage impressed on the pick-up winding a of relay 48 will be reversed with respect to that which exists in the case of an abnormal heat condition occurring in the left-hand axle journal, relay 48 will be picked-up.

In Fig. l I have shown only one pair of axle journals, but it will be understood that the resistance elements in the heat detector cartridges I5 of other pairs of axle journals associated with a common axle on the same car are connected to the bus wires 55 and 5S in parallel relation to those shown in Fig. l. Thus, a single battery 26 may serve as a common voltage source for a plurality of Wheatstone bridge circuits, subject to With the train stopped, therefore,

the control of a single intermittently operated switch device 21. In such case, however, the contacts d of the several relays 48 associated with each Wheatstone bridge respectively must of necessity be connected in parallel if it is desired to employ only one set of signal devices, such as the alarm bell 49, signal lamp 50, and magnet valve 5 l, on each car. If desired, however, each Wheatstone bridge arrangement on each car may have its own set of signal devices controlled by its corresponding relay 48.

It is deemed unnecessary to describe in detail the schematic diagram of the equipment as shown in Fig. 2, since corresponding parts in Figs. l and 2 are designated by the same reference numerals. Fig. 2 serves more readily than does Fig. 1 to convey an understanding of the arrangement of the resistor elements Rl, R2, R3, and R4 in a Wheatstone bridge circuit, as well as of the relative points of connection of the relay 48 and the battery 26 to the Wheatstone bridge circuit.

Figure 3 In Fig. 3, I have indicated a modication of the arrangement shown in Fig. 1, characterized by a heat detector cartridge 15a provided in the place of the heat detector cartridge l5 associated with the right-hand axle journal in Fig. 1.

The cartridge I 5A is essentially the same in structure as the cartridge i5, except for a modified form of base ila substituted for the screw plug Il and an outer enclosure in the form of a tubular housing 14a of insulating material attached to the base. In order to expose the interor of the tubular housing I4a to the ambient temperature. the housing has a plurality of holes or openings therein.

The heat detector cartridge 15A may be disposed and mounted in any convenient location. In the case of a railway car, it may be disposed within the car body so as not to be exposed to extremely low temperature during cold weather, thereby preventing a premature pick-up of the relay 48 due to the initial diierential in the resistance of the resistance elements of the heat detector cartridge 15A with respect to the resistance of the resistance elements in the cartridge I5 associated with an axle journal at normal operating temperatures.

The arrangement employing the heat detector cartridge |5A exposed to ambient temperature is not as desirable for railway car trucks as the two journal arrangement shown in Fig. 1 because it requires twice the number of heat detector cartridges as the arrangement shown in Fig. 1, two detector cartridges being required for each axle journal instead of one as in Fig. 1.

The arrangement including the heat detector cartridge 15A may be employed to advantage, however, in other situations where it is desired to have an indication of abnormal heat condition in a single journal or single bearing of a particular machine, such as a large generator or motor in an electrical power station.

There being no difference in th'e character of ne operation, when employing the cartridge I 5A, with respect to the operation previously described in connection with the embodiment shown in Fig. 1, no further description of this modication is deemed to be required.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1 Apparatus for registering the heat condition in a given zone, said apparatus comprising a Wheatstone bridge circuit having a separate resistance element in each of the four legs thereof, two of said resistance elements being exposed to the heat condition in the given zone and the remaining two resistance elements being exposed to the heat condition in a different zone, means for intermittently impressing a voltage on said bridge circuit, said resistance elements being so arranged and connected that an unbalanced voltage is produced in said circuit while said voltage is impressed thereon upon a variation in the heat condition in the said given zone with respect to the heat condition in the said different zone, electrical relay means operatively responsive to th'e said unbalanced voltage when in excess of a certain value, means for maintaining said relay in its picked-up position notwithstanding cessation of the unbalanced voltage in said bridge circuit, signal means controlled by said relay, and means for restoring said relay to its dropped-out position.

2. Apparatus for registering the heat condition in a given zone, said apparatus comprising a Wheatstone bridge circuit having a separate resistance element in each of the four legs thereof, two of said resistance elements being exposed to the heat condition in the given zone and the remaining two resistance elements being exposed to the heat condition in a different zone, means for intermittently impressing a voltage on said bridge circuit, said resistance elements being so arranged and connected that an unbalanced voltage is produced in said circuit while said voltage is impressed thereon, upon a, variation in the heat condition in the said given zone with respect to the heat condition in the said different zone, an electrical relay having a pick-up winding and a holding winding, said pick-up winding being energized in response to a predetermined unbalanced voltage produced in said bridge circuit to cause actuation of the relay from its dropped-out to its picked-up position, said holding winding of the relay being energized to maintain the relay picked-up in response to pick-up of said relay, signal means operated so long as said relay is picked-up, and manually operated switch means for effecting deenergization of the holding Winding of the relay and the consequent restoration of the relay to its dropped-out position to terminate operation of the signal means.

GEORGE K. NEWELL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,175,432 Garretson Mar. 14, 1916 1,267,757 Gibson May 28, 1918 2,060,215 Hopkins et al. Nov. 10, 1936 2,126,115 Jordi Aug. 9, 1938 2,240,595 White May 6, 1941 2,088,485 Schoepf et al. 1- July 27, 1937 2,164,674 Ziegler July 4, 1939 2,240,595 White May 6, 1941 FOREIGN PATENTS Number Country Date 539,543 Great Britain Sept. 16, 1941 401,667 Germany Sept. 8, 1924

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