US3288992A - Derailment detector actuated brake system - Google Patents

Description

1966 TADASHI MATSUDAIRA ETAL 3,288,992

DERAILMENT DETECTOR ACTUATED BRAKE SYSTEM Filed July so, 1964 2 Sheets-Sheet 1 NOV. 1966 TADASHI MATSUDAIRA ETAL 3,

DERAILMENT DETECTOR ACTUATED BRAKE SYSTEM Filed July 30, 1964 2 Sheets-Sheet 2 FIG. 3

United States Patent f 3,288,992 DERAILMENT DETECTOR ACTUATED BRAKE SYSTEM Tadashi Matsudaira and Yoshio Nomura, Tokyo-to, Japan, assignors to Nippon Kokuyu Tetsudo (known in English as Japanese National Railways), Tokyo-t9, Japan, a juridical person organized under the Public Law of Japan Filed July 30, 1964, Ser. No. 386,334 3 Claims. (Cl. 246-173) This invention relates to a system for detecting derailments of railway vehicles and automatically initiating emergency operation and a safety device therefor, and more particularly to a system which will automatically vent the pressurized air within the brake pipe of the railway vehicles to brake the latter if derailment should occur.

When one or more railway cars of a running passenger or freight train are derailed for some reason, the train often continues to run without the derailment being noticed by the engine driver, brakeman, or conductors if the derailed cars are in the middle of the train. In such a case, the derailed wheels of the cars will often override a branch point of the track or other installations with resultant overturning of the derailed cars. This overturning usually has influence upon the railway cars which have not been derailed, and, consequently, the damage by the derailment is made greater.

Accordingly, it is desirable that when any car of a railway train is derailed, the train be automatically braked so as to stop after a short run, and the trainrnen can notice the derailment.

When cars of a railway train are derailed, they are usually caused to run on the ties or ballasts and, consequently, are subjected to an extremely high vertical acceleration due to vibrations or shocks. This acceleration due to derailment is far greater than that under the normal running condition, and it has been found that this acceleration can be utilized for detecting derailment.

A principal object of this invention isto provide a safety device which will automatically vent a brake pipe of the braking system for the railway train to brake the latter when one or more railway cars of the train are derailed.

Another object of this invention is to provide a safety device of the above character which will automatically restore the braking system, after a braking operation, into the state operable for subsequent braking operation.

Another object of this invention is to provide a safety device of the above character which will operate railway.

The foregoing and other objects of this invention will become more apparent and clear from the following detailed description of preferred non-limiting embodiments of the invention, taken in connection with the accompanying drawings, in which the same or equivalent members are indicated by the like reference numerals and characters, and in which:

FIG. 1 is a schematic diagram of a braking system to which the safety devices according to this invention have been applied.

FIG. 2 is a vertical section of a first embodiment of this invention;

FIG. 3 is a vertical section of a second embodiment of this invention;

FIG. 4 is a vertical section of a third embodiment of this invention; and

FIG. 5 is a vertical section of a fourth embodiment of this invention.

Referring now to FIG. 1, there is shown a schematic diagram of a braking system for railway vehicles, provided with the safety device according to this invention. In this figure, the reference numeral 1 designates a brake pipe in the conventional braking system for railway ve- 3,288,992 Patented Nov. 29, 1966 hicles. The brake pipe 1 is provided with a branch pipe 2 communicating with a pneumatic braking device 3, which includes a control valve, an air reservoir and a brake cylinder (not shown) as is well known.

The safety device according to this invention may be attached to the brake pipe 1 or branch pipe 2 as shown at A, A or B, at the nearest position to the axles.

Referring to FIG. 2, there is illustrated one embodiment of the safety device of the present invention, which is shown as being connected to the brake pipe 1. From the brake pipe 1 there extends a pipe 4 having a cut-off valve 5 which is connected to the safety device S The safety device has a cylindrical housing C and a cap D which is secured onto the housing C by means of bolts 6 and provided with a pipe 4 connecting the device S to the valve 5. A breakable plate 7 of a material which is brittle but of high strength, such as glass, is secured between the housing C and cap D with a packing 8 disposed therearound, and prevents communication from the pipe 4 to the interior chamber 9 of the housing C. The plate 7 is made sufficiently thick so as not to be broken by the air pressure in the pipe 4,. The chamber 9 within the housing C communicates with the atmosphere through vent ports 10 and is always under atmospheric pressure.

Within the housing C there is disposed a Weight 11 which is vertically slidable along the side wall of the housing and includes a sharpened projection 12 thereon confronting the breakable plate 7. The weight 11 is urged toward the bottom wall of the housing C by means of a coiled compression spring 13 inserted between the top wall of the housing C and the top face of the weight 11. The force of the spring 13 is so determined that the weight 11 will not be caused to rise by vibrations or shocks as occur under the usual running conditions of the train. The weight 11 is confined by the side wall of the housing C and is slidable only vertically by the guiding action of the housing.

The safety device S as described above must be vertically attached to the railway vehicle. It may be secured to the floors of the vehicles and connected with the brake pipe or secured directly to the brake pipe without being otherwise supported.

According to such construction and arrangement of the device, the shocks or vibrations as will occur under the normal running condition of railway cars cannot cause the vertical move-ment of the weight 11 relative to the housing C. However, if even one pair of wheels of a railway car are derailed and run on the ties and other objects, a very high acceleration will be imparted to the derailed railway car with the result that the weight 11 will overcome the force of the spring 13 and plunge upwardly. Thus, the sharpened end of the projection 12 on the weight 11 will strike against the lower surface of the breakable plate 7 to break it. Once a small break occurs, the pressurized air within the pipe 4, will make the break larger and will be rapidly vented through the broken plate, the chamber 9 and the ports 16 into the atmosphere. Thus, the air pressure within the brake pipe 1 will be reduced, thereby causing the braking device 3 to operate to brake the train according to known principle.

After the train is stopped by the braking action, the braking system may be put into the original operable condition simply by manually closing the cut-off valve 5. The breakable plate 7 is readily replaceable. Thus, it is apparent that the restoration of the braking system including the safety device may be easily effected.

When the braking system is operated with reduced air pressure within the brake pipe as aforementioned, all of the cars in the train, including those not derailed, will come under the influence of the braking system. Therefore, the train will be quickly braked and automatically stopped even if a pair of wheels of an intermediate car of the train are derailed. Thus, thede-railmcnt will not cause overturning of the train. Moreover, since the sudden reduction of air pressure in the air pipe 1 and the sudden retardation of the train may be readily noticed by the engine driver and other trainrnen, they can promptly resort to appropriate measures for the derailment.

In FIG. 3, another embodiment of the safety device of the present invention is illustrated. This safety device S is also shown as being connected to the brake pipe 1 having the pipe 4, and comprises a housing C and a cap D secured onto the housing C. The cap D is in the form of a cylinder having a top wall 20 with an opening 21 therein and a bottom wall 22 with an opening 23, and is connected to the pipe 4*at the portion of the opening 21. The top and bottom walls 20 and 22 and the side wall of the cap D define a chamber 24 therein. The cap I) is also provided with a peripheral flange 25, which is placed on a peripheral flange 27 extending from the upper edge of the housing C to be bolted to the flange 27 as shown at 26 with a packing therebetween. The opening 23 in the wall 22 has at the lower edge thereof an annular projection 28 forming' a seat for a packing which will be hereinafter described.

A weight 29 is arranged within the housing C for vertical sliding movement therealong and is provided on the upper face thereof with a projection 30 having thereon a packing 31. The weight 29 is urged upwardly by means of a coiled compression, spring 32 arranged between the weight and the bottom wall of the housing C so that the packing 31 on the projection 30 is always in tight contact with the seat 28 thereby closing the opening 23.

The force of the spring 32 urging the weight upwardly is selected so as to be slightly less than the sum of the downward force 'of the pressurized air acting on the projection 30 through the opening 23, the gravitational force acting on the weight, and a downward force which is caused by the acceleration of the weight 29 in the case of derailment of the railway ear.

The internal chamber 33 of the housing C above the weight 29 is in communication with the atmosphere through a throttled vent port 34. The internal chamber 35 of the housing below the weight is also in communica-' tion with the atmosphere through a port 36.

In the normal running condition of the railway car, the pressurized air within the chamber 24 cannot flow into the atmosphere, since the packing 31 on the top of the projection 30 is in tight engagement with the seat 28 so as to close the opening 23. However, if any derailment occurs with the resultant vertical acceleration imparted to the railway car, the weight 29 will be driven downwardly to cause the packing 31 to leave the seat 28. Once the packing 31 moves away from the seat 28 through a small distance, the pressurized air within the chamber 24 of the cap D will flow into the chamber 33 above the weight 29 thus increasing the .air pressure therein and then flow into the atmosphere through the vent port 34. In this case, the air pressure within the chamber 33 of the housing will be maintained at a pressure lower than that in the chamber 24 but higher than the atmospheric pressure since the vent port 34 is throttled and restricts the flow of air therethrough.

This air pressure within the chamber 33- will act upon the entire upper surface area of the weight 29, which is larger than the transverse sectional area of the opening 23 and will, therefore, produce a downward force suflicient to compress the spring 32. Accordingly, once the weight 29 moves downwardly, the chamber 24 will be continu ously maintained in communication with the atmosphere and the pressurized air within the brake pipe 1 will be continuously vented into the atmosphere, thus causing the braking system to operate.

When the brake pipe pressure is reduced to a considerable low value after the train has been stopped by the braking action, the air pressure within the chamber 33 of the housing C will be corresponding reduced. Under such circumstances, the downward force due to the air pressure within the chamber 33, acting upon the upper surface of the weight 29, will be overcome by the force of the spring 32 so that the weight 29 will be moved upwardly until the packing 31 is brought into tight engagement with the seat 28 to close the opening 23.

In the operation above mentioned, the port 36 cut in the bottom wall of the housing C serves to release the air within the chamber into the atmosphere when the weight 29 moves downwardly, and prevents the air within the chamber 35 from being compressed, thereby eliminating the resistance to the downward movement of the weight 29.

The safety device S as described above in connection with FIG. 3 has the same function of affording safety in the event of derailments as the device of FIG. 2; that is, the device of FIG. 3 has the function of detecting derailments and then causing the brake pipe pressure to be reduced so as to actuate the braking system, as in the case of the device of FIG. 2. In addition to this safety function, the device of FIG. 3 has a self-restoring characteristic capable of making the weight 29 return upwardly to its original position in response to the substantial reduction of the brake pipe pressure due to the venting of the air. This self-restoring characteristic of the device is very convenient since the braking system, after the stoppage of the train, automatically returns to its original state operable for braking without any corrective measures on the part of an operator.

Referring to FIG. 4, there is illustrated another embodiment of the present invention. The safety device S shown in this figure is of breakable plate type and is constructed so as to afford a more reliable operation.

The device S comprises a housing E and a base F forming the bottom of the housing. The housing E is in the form of a cylinder and includes an internal chamber 40 therethrough having an upper horizontal opening 41 and a lower opening 42, said upper opening 41 communicating with a brake pipe 1 (not shown).

The base F is in the form of a relatively thick circular plate and includes a central vent port 43 therethrough axially aligned with the chamber 40 of the housing E.

On the upper surface of the base F there is placed a breakable plate 44 of a material such as glass so as to cover the upper end of the vent port 43. The base F also supports thereon an annular block 45 having an inner shoulder 46 formed at the inner lower edge thereof and an outer shoulder 47 formed at the outer lower edge thereof. The annular block 45 is in axial alignment with the base F and the peripheral edge of the breakable plate 44 is engaged with the inner shoulder 46 of the block 45 with an annular packing 48 therebetween. Another annular packing 49 is also fitted within the outer shoulder 47 of the block 45.

The cylindrical housing E has an inner shoulder 50 at the lower edge thereof which is adapted to engage the upper peripheral edge of the block 45. Thus, when the housing E is rigidly secured to the base F, the annular block 45 is held between the shoulder 50 and the base F and the breakable plate 44 is also secured between the block 45 and the base F. Once such an assembly is completed, the packings 48 and 49 create an airtight condition, and the breakable plate 44 prevents communication from the chamber 40 to the port 43.

In the chamber 40 of the housing B there is disposed a weight 51 which is always urged upwardly by means of a coiled compression spring 52 inserted between the upper face of the block 45 and a shoulder 53 of the weight 51. The weight 51 is vertically movable against the force of the spring 52 and in its uppermost position engages with a portion 54 of reduced diameter within the housing. Vertical passages 55 extend through the weight 51 and permit the introduction of pressurized air into the space below the Weight 51. The weight 51 is provided with a projection 56 extending downwardly from the chamber 40 below the weight 51 is prevented from being vented into the atmosphere by the breakable plate 44.

However, if derailment occurs with the resultant vertical acceleration imposed on the vehicle, the weight 51 will be driven downwardly so that the downwardly extending projection 56 thereof will forcibly strike and break the breakable plate 44. In this case, even though a complete breakage of the plate 44 cannot be attained, with the plate being only cracked to a degree to allow air to pass therethrough, the pressurized air within the chamber 40 will be vented into the atmosphere through the port 43, which venting will create a pressure difference between the space above the weight 51 and that below the weight due to the throttling etfect of the channels 55, so that the weight will be pushed downwardly to completely break the plate 44. When the breakable plate 44 is completely broken, the pressurized air within the brake pipe will flow in substantial quantity through the upper space of the chamber 40, the channels 55, the lower space of the chamber 40, and the vent port 43 to be vented into the atmosphere. Thus, the vehicle braking operation is carried out.

Referring to FIG. 5, a still another embodiment of the present invention will be described. The device 8.; illustrated in this figure is of the self-restoring type, as shown in FIG. 3, in which a valve arrangement is used to vent the air upon derailment.

The device comprises an upper cylindrical housing G, and a lower cylindrical housing H secured to the upper housing G by any suitable means. The upper housing G has therein a substantially horizontal inlet chamber 60, a downwardly opening central chamber 61 communicable with the inlet chamber 66, and a vent port 62 horizontally extending from the central chamber 61. The upper housing G also has therein a vertical passage 63 extending downwardly from the horizontal inlet chamber 66,

The lower housing H is in the form of a cup and includes therein an upwardly opening chamber 64 and an L-shaped passage 65 communicating with the bottom of the chamber 64. When these upper and lower housings G and H are assembled, the chamber 61 of the housing G and the chamber 64 of the housing H together form an internal chamber extending axially through the device, and the passages 63 and 65 also form a passage leading from the inlet chamber 60 to the bottom of the chamber 64.

Within the internal chamber of the device there is disposed a weight 66 which is movable axially along the wall of the chamber and is urged downwardly by means of a coiled compression spring 67 inserted between the top wall of the chamber 61 and the top face of the weight 66. The weight 66, in its downwardly urged, lowermost position, tightly closes the opening of the passage 64 through a packing 68 interposed therebetween. The weight 66 is provided on its top with a projection 69 which is upwardly extended into a channel 70 which connects the inlet chamber 60 to the central chamber 61 and is provided at the uppermost peripheral edge thereof with a valve seat 71.

Through the top wall of the housing G there is provided an inverted cup-shaped member 7Q having a downwardly opening chamber 73. On the valve seat 71 there rests a valve plate 74 pressed thereaigainst by a compression spring 75 disposed within the chamber 73. The valve plate 74 is vertically movable against the force of the spring 75 and along guide extensions 76 of the member 72.

The inlet chamber 60 is connected at its outer end to a brake pipe (not shown) and is in communication with the chamber 73 of the member 72. Since the chamber 61 is under atmospheric pressure, and a force is exerted upon the upper surface of valve plate 74 by both the spring 75 and the pressurized air within the chamber 73, the valve plate 74 is norm-ally in tight engagement with the valve seat 71.

The force of the spring 67 is selected so as to be slightly less than the total value of the upward force exerted on the bottom of the weight 66 by the pressurized air within the channel 65 when the weight is closing the latter and the upward force due to the acceleration which occurs in the event of derailment.

In the normal running condition of the railway vehicle, the device S is maintained in the state shown in FIG. 5 with the valve plate 74 in tight engagement with the valve seat 71, and'the air pressure within the inlet chamber 60 and, therefore, within the brake pipe is maintained at a desired level without the air being vented into the atmosphere. However, if derailment occurs, the weight 66 will be impelled upwardly by the resulting acceleration. Once the weight 66 leaves the bottom of the chamber 64 through even a small distance, the pressurized air within the channel 65 will lflOW into the chamber 64 below the weight 66 and push the latter upwardly because the surface area of the weight acted upon by the pressurized air from the channel 65 is thereby increased, so that the upward force due to the pressunized air from the channel 65 overcomes the gravitational force upon the weight and the force of the spring 67.

This upward movement of the weight causes the projection 69 thereof to lift the valve plate 74 so as to allow the pressurized air within the brake pipe to be vented into the atmosphere through the chambers 66 and 73, the channel 70, the chamber 61, and the port 62. Thus, the braking operation will be effected.

When the air pressure within the brake pipe is reduced to a substantial degree, both the gravitational force acting upon the Weight and the force of the spring 67 cause the weight to move downwardly into engagement with the bottom of the chamber 64 thus preventing the communication between the chamber 64 and the channel 65, while the valve plate 74 returns to its initial position in which it is in tight engagement with the seat 71, as shown in FIG. 5.

In the embodiment shown in FIG. 5, the valve plate 74 may be replaced by a breakable plate, for example, of glass, tightly secured on the seat 71. In such a case, the breakable plate will be broken by the projection 69 upon the upward movement of the weight 66, thereby venting the pressurized air.

When a braking system of electrically operated type is to be employed, electric contacts may be provided at the portion of the breakable plate or the valve arrangement of the device according to this invention, so as to be closed by the movement of the weight upon derailment to establish an electric circuit for braking. In such a case, the electric circuit for braking may be uti lized for actuating an emergency alarm which may be installed in the engine drivers cab or a trainmans 'roo-m.

While preferred embodiments of this invention have been shown and described in the foregoing disclosure, it is to be understood that this invention may be modified or changed without departing from the spirit and scope of this invention as set forth in the following appended claims.

What is claimed is:

1. A safety device adapted to be connected to a brake pipe of the pneumatic braking system of a railway vehicle for detecting derailment of the vehicle and automatically causing braking action, said device comprising a housing adapted to be connected with the brake pipe in communicating relation thereto and having a vertical- [y extending internal chamber therein, said chamber having a vent port leading to the atmosphere, intercepting means for normally preventing communication from said brake pipe into said chamber, a weight vertically movable Within said chamber, and spring means for urging said weight toward one vertical end of said chamber so as to hold the weight at rest under normal running condition act the vehicle but to allow the same to move vertically by the force of acceleration due to derailment of the vehicle against the force of the spring means toward the other vertical end of the chamber, the relation between said intercepting means and said weight being such that when the weight moves toward said other vertical end J'f the chamber, said intercepting means is caused to aliow communication from said brake ipipe into said chamber, thereby venting the pressurized air within the brake pipe into the atmosphere through said vent port to cause braking action of the brake system.

2. The safety device according to claim 1, wherein said intercepting means is a breakable plate of a material which is brittle but of high strength, secured between said brake pipe and said chamber, and is adapted to be broken by the movement of said weight toward said other vertical end of said chamber.

3. The safety device according to claim 1, wherein said intercepting :means is a normally closed valve means adapted to be opened by the movement of said Weight toward said other vertical end of said chamber.

References Cited by the Examiner UNITED STATES PATENTS 998,513 7/1911 Hill 246173 1,646,306 10/1927 Milton 246172 2,626,625 1/1953 Versoy 13738 2,760,484- 3/1956 Ferwerda 137-38 X 3,127,958 4/1964 Szostak 13738 X EUGENE o. BOTZ, Primary Examiner.

Claims (1)

1. A SAFETY DEVICE ADAPTED TO BE CONNECTED TO A BRAKE PIPE OF THE PNEUMATIC BRAKING SYSTEM OF A RAILWAY VEHICLE FOR DETECTING DERAILMENT OF THE VEHICLE AND AUTOMATICALLY CAUSING BRAKING ACTION, SAID DEVICE COMPRISING A HOUSING ADAPTED TO BE CONNECTED WITH THE BRAKE PIPE IN COMMUNICATING RELATION THERETO AND HAVING A VERTICALLY EXTENDING INTERNAL CHAMBER THEREIN, SAID CHAMBER HAVING A VENT PORT LEADING TO THE ATMOSPHERE, INTERCEPTING MEANS FOR NORMALLY PREVENTING COMMUNICATION FROM SAID BRAKE PIPE INTO SAID CHAMBER, A WEIGHT VERTICALLY MOVABLE WITHIN SAID CHAMBER, AND SPRING MEANS FOR URGING SAID WEIGHT TOWARD ONE VERTICAL END OF SAID CHAMBER SO AS TO HOLD THE WEIGHT AT REST UNDER NORMAL RUNNING CONDITION OF THE VEHICLE BUT TO ALLOW THE SAME TO MOVE VERTICALLY BY THE FORCE OF ACCELERATION DUE TO DERAILMENT OF THE VEHICLE AGAINST THE FORCE OF THE SPRING MEANS TOWARD THE OTHER VERTICAL END OF THE CHAMBER, THE RELATION BETWEEN SAID INTERCEPTING MEANS AND SAID WEIGHT BEING SUCH THAT WHEN THE WEIGHT MOVES TOWARD SAID OTHER VERTICAL END OF THE CHAMBER, SAID INTERCEPTING MEANS IS CAUSED TO ALLOW COMMUNICATION FROM SAID BRAKE PIPE INTO SAID CHAMBER, THEREBY VENTING THE PRESSURIZED AIR WITHIN THE BRAKE PIPE INTO THE ATMOSPHERE THROUGH SAID VENT PORT TO CAUSE BRAKING ACTION OF THE BRAKE SYSTEM.

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