US1479062A - Safety mechanism for doors - Google Patents

Safety mechanism for doors Download PDF

Info

Publication number
US1479062A
US1479062A US323657A US32365719A US1479062A US 1479062 A US1479062 A US 1479062A US 323657 A US323657 A US 323657A US 32365719 A US32365719 A US 32365719A US 1479062 A US1479062 A US 1479062A
Authority
US
United States
Prior art keywords
door
doors
valve
pipe
fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US323657A
Inventor
Gottschalk Albert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
National Pneumatic Co Inc
Original Assignee
National Pneumatic Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by National Pneumatic Co Inc filed Critical National Pneumatic Co Inc
Priority to US323657A priority Critical patent/US1479062A/en
Application granted granted Critical
Publication of US1479062A publication Critical patent/US1479062A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B61RAILWAYS
    • B61DBODY DETAILS OR KINDS OF RAILWAY VEHICLES
    • B61D19/00Door arrangements specially adapted for rail vehicles
    • B61D19/02Door arrangements specially adapted for rail vehicles for carriages

Definitions

  • Vsafet mechanism to be used in connection with oors, and EL@ particularly car doors, where it 1s desired that the car or train should not start until all of the doors are closed.
  • apparatus of this type means have been employed for giving an indication or signal to the motorl man, or operator, when all of the doors are closed, and such signals .may be of various forms, either visual or audible.
  • This 1nd1- eatin device may also be used for controlling, y suitable means, the power as applied 2o for propellin the vehicle, car, or train,
  • the motorman may turn his power controller to running position when the car has stopped, and the doors are open; then as soon as the last door is closed, the device will operate automatically to apply the power and start the car promptly and without delay.
  • Such a device for' controlling the application of the power, or for giving the indication to the motorman may be termed an indicating or control device, and may be embodied in various different forms.
  • my improvement may be said to comprise an indicating or control device and fluid ressure means governed by the position ofp the doors for operating the same, whereby the device is automatically operated to the starting position when the door, or all of the doors, is or are moved to the closed position, and is otherwise operated when the door, or any one or more of the doors, is or are opened or moved away from the closed position.
  • Any suitable or preferred form of means governed by the position or movement of the door, either directly or indirectly, may be employed for controlling the fluid pressure for operating the indicating or control device.
  • Figure 1 is a diagram illustrating a car equipment embodying my improvement as applied to a plurality (three) of doors; Fig. 2, a sectional vlew of one form of valve device governed b the position of the door; Fig. 3, a sectiona view of one form of iuid pressure operated indicating or control device; Fig. 4, another diagram showing a modification in which the 'doors' are operated by fluid pressure motors; Fig. 5, a sectional view of the governing valve employed in Fig. 4; and Fig.. 6, a diagram showing another modification.
  • Y is a diagram illustrating a car equipment embodying my improvement as applied to a plurality (three) of doors; Fig. 2, a sectional vlew of one form of valve device governed b the position of the door; Fig. 3, a sectiona view of one form of iuid pressure operated indicating or control device; Fig. 4, another diagram showing a modification in which the 'doors' are operated by fluid pressure motors;
  • the electric switch may serve to control the operation of a signal, or the application of power for propelling the car, or both, as will be readily understood, and these devices are usually located at the end of the car, or in the motormans cab, it also being understood that ordinarily only one of such devices is cut in for operation upon the car or train.
  • 'Ihe pipe, 15, is shown as extending the length of the car, and provided with suitable hose and couplings for connecting the same to the corresponding ipe on adjolning cars of the train, as will e readily understood.
  • Huid pressure such as reservoir, 17, and supply pipe, 18, which may also extend through the train by the usual couplings, and is provided .with any suitable means for supplying fluid to the pipe or conduit, 15, such as branch pipes, 19, having cut out cocks.
  • valve device 20 governed byv'the position or movement of the door for controlling the pressure through pipe, 15, to the indicating or control device is shown in Fig. 2, and comprises a casing having a valve chamber, 21, containing a valve, 22, fory controlling communication through the pipe, 15, and operated by a stem, 23, extending outside of the casing.
  • the stem is adapted to be engaged by the door, 8, o r any .other part moving with the door, in
  • any suitable means may be provided for closing the valve and cutting offl communication through the pipe when the door is opened or moved away from its closed position.
  • the fluid pressure acting on piston, 24 immediately moves the valve to its other position in which communication from one section of pipe, 15, to the other is i cut off.
  • the valve device may also have an exhaust port, 25, ⁇ which, in this position of the valve, isconnected by the cavity, 26, in said valve, to the section of the pipe, 15, leading toward the indicating or control device, for the purpose of releasing the fluid pressure therefrom.
  • the governing valve is located in the pipe, 15, between the indicating or control device and the source of fluid pressure supply, and, in like manner, if there are a plurality of doors, the supply of fluid to pipe, 15, is located beyond the last one of the governing valves, so that all of the said governing valves. one for each door, shall be located along the pipe, 15, be-
  • any one of the doors should not be closed, the governing valve at such door would remain closed, and cut ofl' communication through the pipe, 15, so that fluid could not be admitted to the piston of the control switch, and the spring, 16, would hold said switch in its open position.
  • an additional hand release valve, 26, may be connected to the pipe, 15, at or near the indicating or control device for exhausting fluid therefrom manually' at such times as the doors are opened after the train has come to a stop, and such valve may or may not be the same valve as is employed for controlling the opening and closing of the'doors.
  • supply pipe, 18, may be connected to the pipe, 15, by merely attaching their couplings together at the end of the car or train, and this will serve the purpose of the cross over pipes, 19; If the latter are employed, however, all except the one at the end of the car or train will ordinarily be cut out.
  • l have illustrated my improvement as applied in connection with doors operated by a well known standard form of fluid pressure motor, 8b, having a swinging arm, 8a, adapted to be attached to the door.
  • the piston With this form of fluid pressure motor, the piston is moved to one position for closing the door, and to its opposite position for opening the door in the usual way, and, according to one feature of my improvement, the goveining valve may be actuated by fluid pressure controlled by the movement of the motor piston.
  • a pipe,28 communicates with a port in the motor cylinder, so located as to be opened when the motor piston reaches its closed door position whereupon fluid from the motor cylinder flows through pipe, 28, to the governing valve device, 20a.
  • This device is substantially the same as that of Fig. 2 for con trolling communication through the pipe, 15, except that instead of the valve, 22 ⁇ being actuated by a direct engagement of the door or other part, with the stem, 23. fluid from pipe, 28, is admitted to the outer side of piston, 24, and, co-operating with spring,
  • valve chamber, -21 acting on piston, 24, overcomes the spring, 27, and moves the valve to its closed osition to cut combination.
  • a safety mechanism adapted to effect control of an associated power motor, the combination with a door, and a motor for actuating said door, of a fluid pressure operated indicating or control device, and means governed by the movement of the door acofi' communication through p1pe, 15, and to ⁇ t uating motor to close the door for admitopen the exhaust port, 25, from the section .of pipe, 15, in advance of the valve, to the atmosphere.
  • the operation of this modification is the same as that before described with reference to Figs. l,
  • a safety mechanism the combination with a door, and a motor for actuating said door, of a Huid pressure operated indicating or control device, and means overned by the movement of the motor to c ose the door for admittin Huid to said device, and by the movement o the motor to open the door for releasing fluid from said device.
  • a safety mechanism the combination withl a door, and a fluid ressure motor for actuating said door, of a uid pressure operated ind1cating or control device, a valve for controlling a su ply of duid to said device, a piston norma y subject to fluid ressure for holding the valve in one posit1on, and means governed by the movement of the motor for varying the fluid pressure on one side of said piston, to move said valve to another position.
  • a safet mechanism the combination with a'door, o a fluid pressure operated indicating or control device, a valve for controlling a supply of fluid to said device, a piston connected to said valve and normally subject to duid pressure on one side for holding the valve 1n one position, and means governed by the movement of the door to closed position for actuating said valve to another position.
  • a safety mechanism the combination with a door, and a fluid pressure motor for actuating said door, of a fluid pressure operated indicating or control device, and means governed -by the movement of the motor piston to its closed position for admitting fluid to said control device.
  • a safety mechanism the combination with a plurality of doors, of a fluid pressure operated indicating or control device, a Huid pressure conduit leading from a source of supply to said device, a valve for said conduit at each door, and means governed by the movement of the doors to closed position for opening said valves.
  • a safety mechanism the combination with a plurality of doors, of a fluid pressure operated indicating or control device, a fluid pressure conduit leading from a source of supply to said device, a valve for said conduit at each door, and means governed by the movement of the doors to closed position to open said valves, and by movement of the doors away from closed position to close said valves.
  • a safety mechanism the combination with a plurality of doors, of a Huid pressure operated indicating or control device, a Huid pressure conduit leading from a Source of supply to said device, a valve at each door,
  • va ves being located in the conduit be- ALBERT GOTTSCHALK.

Description

Jn. l, 1924 1,479,062
A. GoTTscHALK SAFETY MECHANISM Fon DooRs i Filed Sept. l5, 1919 2 Sheets-Sheet l Tip: 5:1: o :if N
L, 2 'o Q J N #www ATToR Jan. 1, 1924 A. GOTTSCHALK SAFETY MECHANISM FOR DOORS Filed Sept. 13, 1919 2 Sheets-Sheet 2 Lm IJENTOR f ATTORN Patented dan. I, 11924.
unir raras ANT FFIIC.
' I ALBERTGOTTSCLK, OF NEW YORK, N. Y., ASSIGNOR TO NATIONAL PNEUMATIC COMPANY, 'OF NEW YORK, N. Y., CORPORATION OF WEST VIRGINIA.
SAFETY MECHANISIVI FOR DOORS.
Application filed September 18, 1919. Serial No. 323,657.
To all whom it may concern Be it known that I, ALBERT GorrsoHALK, of New York, in the county of Bronx and State of New York, have invented a certaln new U and useful Improvement in Safety Mechanism for Doors, of which improvement the following is a specification.
'Ihis invention relates to Vsafet mechanism to be used in connection with oors, and EL@ particularly car doors, where it 1s desired that the car or train should not start until all of the doors are closed. In apparatus of this type means have been employed for giving an indication or signal to the motorl man, or operator, when all of the doors are closed, and such signals .may be of various forms, either visual or audible. This 1nd1- eatin device may also be used for controlling, y suitable means, the power as applied 2o for propellin the vehicle, car, or train,
whereby it wil be impossible for the operator to start until all of the doors are closed.
With this control device the motorman may turn his power controller to running position when the car has stopped, and the doors are open; then as soon as the last door is closed, the device will operate automatically to apply the power and start the car promptly and without delay.
Such a device for' controlling the application of the power, or for giving the indication to the motorman, may be termed an indicating or control device, and may be embodied in various different forms.
rIhe object of my invention is to provide an improved device of this character which shall be positive, accurate, and reliable in its operation, and adapted to be applied to one or more doors, or to one or more cars of a train, whether the doors are operated manually, or by motors, and either singly or collectively, or separatel and independently by the guards or plat orm men, as desired. Broadly stated, my improvement may be said to comprise an indicating or control device and fluid ressure means governed by the position ofp the doors for operating the same, whereby the device is automatically operated to the starting position when the door, or all of the doors, is or are moved to the closed position, and is otherwise operated when the door, or any one or more of the doors, is or are opened or moved away from the closed position. Any suitable or preferred form of means governed by the position or movement of the door, either directly or indirectly, may be employed for controlling the fluid pressure for operating the indicating or control device.
In the accompanying drawing: Figure 1 is a diagram illustrating a car equipment embodying my improvement as applied to a plurality (three) of doors; Fig. 2, a sectional vlew of one form of valve device governed b the position of the door; Fig. 3, a sectiona view of one form of iuid pressure operated indicating or control device; Fig. 4, another diagram showing a modification in which the 'doors' are operated by fluid pressure motors; Fig. 5, a sectional view of the governing valve employed in Fig. 4; and Fig.. 6, a diagram showing another modification. Y
In the class of service for which my improvement is particularly designed, such as as cars or trains operating on the multipleunit principle. as in the traic on subways, elevated, and inter-urban railroads, the cars are usually provided with a number of doors on each side, and in the diagram, Fig. 1, I
have illustrated three such doors, 8, but it will be understood that in accordance with my invention, one or any number of doors may be employed, the same being suitably connected up to govern the operation of the indicating or control device, 9. While this device may also assume various forms, I prefer to illustrate the same as an electric switch having lixed contacts, 10, and a movable contact, 11, carried by the stem, 12, of a piston, 13, mounted in cylinder, 14, and actuated by fluid pressure admitted through pipe, 15, and by a spring, 16, (see Fig. 3). The electric switch may serve to control the operation of a signal, or the application of power for propelling the car, or both, as will be readily understood, and these devices are usually located at the end of the car, or in the motormans cab, it also being understood that ordinarily only one of such devices is cut in for operation upon the car or train. 'Ihe pipe, 15, is shown as extending the length of the car, and provided with suitable hose and couplings for connecting the same to the corresponding ipe on adjolning cars of the train, as will e readily understood. There is also indicated a source of Huid pressure, such as reservoir, 17, and supply pipe, 18, which may also extend through the train by the usual couplings, and is provided .with any suitable means for supplying fluid to the pipe or conduit, 15, such as branch pipes, 19, having cut out cocks.
@ne form of valve device, 20, governed byv'the position or movement of the door for controlling the pressure through pipe, 15, to the indicating or control device is shown in Fig. 2, and comprises a casing having a valve chamber, 21, containing a valve, 22, fory controlling communication through the pipe, 15, and operated by a stem, 23, extending outside of the casing. The stem is adapted to be engaged by the door, 8, o r any .other part moving with the door, in
sucha manner that when the door moves toits closed position, the valve is moved thereby toits position .for opening communication through the p1pe, 15, that is, the
two sections ofthe pipe are connected together through the cavity, 26, in the valve,
` as indicated in Fig. 2. Any suitable means may be provided for closing the valve and cutting offl communication through the pipe when the door is opened or moved away from its closed position. For such purpose, I have shown a piston, 24, mounted on the stem, 23, of the valve, and subject on one side to the fluid pressure in the valve chamber, 21, admitted from the supply pipe, 18. rll`he chamber at the other side of the piston is open to the atmosphere through the opening around the loose fitting stem, 23. When the door or other moving part recedes from the stem, 23, the fluid pressure acting on piston, 24, immediately moves the valve to its other position in which communication from one section of pipe, 15, to the other is i cut off. The valve device may also have an exhaust port, 25,`which, in this position of the valve, isconnected by the cavity, 26, in said valve, to the section of the pipe, 15, leading toward the indicating or control device, for the purpose of releasing the fluid pressure therefrom. t;
With this construction, if there is only one door to be operated, the governing valve is located in the pipe, 15, between the indicating or control device and the source of fluid pressure supply, and, in like manner, if there are a plurality of doors, the supply of fluid to pipe, 15, is located beyond the last one of the governing valves, so that all of the said governing valves. one for each door, shall be located along the pipe, 15, be-
tween the source of supply of fluid and the indicating or control evice, and each governing valve controls communication through said pipe. It will, therefore, be seen that when all of the doors have reached the closed position, communication will be opened throughout the pipe, 15, by the governing valves at the respective doors, so that fluid will flow to the indicating or control device and act on its piston, 13, to close the electric switch member, 11. If, however,
any one of the doors should not be closed, the governing valve at such door would remain closed, and cut ofl' communication through the pipe, 15, so that fluid could not be admitted to the piston of the control switch, and the spring, 16, would hold said switch in its open position.
When the car or train comes to a stop, and any one or more of the doors are opened, fluid is then released from the piston, 13, and pipe, 15, through the exhaust port, or ports, 25, of such valves as are shifted, and the spring, 16, then returns the indicatin or control switch to its other position until kall of the doors are again closed, when the car may again proceed. If desired, an additional hand release valve, 26, may be connected to the pipe, 15, at or near the indicating or control device for exhausting fluid therefrom manually' at such times as the doors are opened after the train has come to a stop, and such valve may or may not be the same valve as is employed for controlling the opening and closing of the'doors. `While it is not ordinarily necessary to employ such manually controlled exhaust valve where the governing valves, 20, are provided, with the exhaust ports, 25, it may be used if preferred, and in some cases the exhaust ports, 25, may be dispensed with.
It will be evident that the supply pipe, 18, may be connected to the pipe, 15, by merely attaching their couplings together at the end of the car or train, and this will serve the purpose of the cross over pipes, 19; If the latter are employed, however, all except the one at the end of the car or train will ordinarily be cut out.
In the modification shown in Figs. 4 and 5, l have illustrated my improvement as applied in connection with doors operated by a well known standard form of fluid pressure motor, 8b, having a swinging arm, 8a, adapted to be attached to the door. With this form of fluid pressure motor, the piston is moved to one position for closing the door, and to its opposite position for opening the door in the usual way, and, according to one feature of my improvement, the goveining valve may be actuated by fluid pressure controlled by the movement of the motor piston. For this purpose, a pipe,28, communicates with a port in the motor cylinder, so located as to be opened when the motor piston reaches its closed door position whereupon fluid from the motor cylinder flows through pipe, 28, to the governing valve device, 20a. This device, as shown in Fig. 5, is substantially the same as that of Fig. 2 for con trolling communication through the pipe, 15, except that instead of the valve, 22` being actuated by a direct engagement of the door or other part, with the stem, 23. fluid from pipe, 28, is admitted to the outer side of piston, 24, and, co-operating with spring,
Laracea v pipe, 28, and the outer side of piston, 24, is
exhausted to the atmosphere, and the pressure in the valve chamber, -21, acting on piston, 24, overcomes the spring, 27, and moves the valve to its closed osition to cut combination. with a door and a motor for actuatin sald door, of a fluid pressure operated indlcatin or control devlce, and means governed by t e movement of the door actuating motor for varying the Huidpressure actingv on said device.
` 2. 1n a safety mechanism adapted to effect control of an associated power motor, the combination with a door, and a motor for actuating said door, of a fluid pressure operated indicating or control device, and means governed by the movement of the door acofi' communication through p1pe, 15, and to\\t uating motor to close the door for admitopen the exhaust port, 25, from the section .of pipe, 15, in advance of the valve, to the atmosphere. In other respects, the operation of this modification is the same as that before described with reference to Figs. l,
'2 and 3.
In the modification shown in lFig. 6, ll
- have illustrated a simple form of my improvement, in which the separate governing valve for each door is eliminated, and the pipe, 28, from the openin in the motor cylinder, is connected direct y to the pipe, 15, leading to the piston of the indicatmg or control device, 9. In this construction, when one door motor moves to closed position, fluid pressure is supplied to the pipe, 15, but as long as one or more of the other door motors have not reached the closed position, the fluid from said pipe, 15, escapes through the pipes, 28, of such motors, so that pressure acting on the piston, 13, of the indicating or controlv device, 9, does not accumulate sufficiently to actuate said device. When, however, all of the door motors have moved to closed position, the escape of fluid is stopped, and the pressure immediately accumulates on piston, 13, and operates the device to its starting position.
From the foregomg, it will now be apparent that my improvement has the advantage of providing a positivel and reliable indication or control, regardless of the system under which the doors may be operated, that is, whether the doors are all operated collectively from a single point, as for instance, by the motorman, or operated selectively, as where the doors of each car may be o erated by a guard or conductor, or operate single and independently, as by a guard or platform man stationed at each door. lin all cases, the clear indication or control forV ting duid under pressure to said device to thereby automatically place said-power motor into operation.
3. 1n a safety mechanism, the combination with a door, and a motor for actuating said door, of a Huid pressure operated indicating or control device, and means overned by the movement of the motor to c ose the door for admittin Huid to said device, and by the movement o the motor to open the door for releasing fluid from said device.
4. lin a safety mechanism, the combination withl a door, and a fluid ressure motor for actuating said door, of a uid pressure operated ind1cating or control device, a valve for controlling a su ply of duid to said device, a piston norma y subject to fluid ressure for holding the valve in one posit1on, and means governed by the movement of the motor for varying the fluid pressure on one side of said piston, to move said valve to another position.
5. 1n a safet mechanism, the combination with a'door, o a fluid pressure operated indicating or control device, a valve for controlling a supply of fluid to said device, a piston connected to said valve and normally subject to duid pressure on one side for holding the valve 1n one position, and means governed by the movement of the door to closed position for actuating said valve to another position.
6. ln a safety mechanism, the combination with a door, and a fluid pressure motor for actuating said door, of a fluid pressure operated indicating or control device, and means governed -by the movement of the motor piston to its closed position for admitting fluid to said control device.
` 7. lln a safety mechanism, the combination with a plurality of doors, of a fluid pressure operated indicating or control device, a Huid pressure conduit leading from a source of supply to said device, a valve for said conduit at each door, and means governed by the movement of the doors to closed position for opening said valves.
8. lin a safety mechanism, the combination with a plurality of doors, of a fluid pressure operated indicating or control device, a fluid pressure conduit leading from a source of supply to said device, a valve for said conduit at each door, and means governed by the movement of the doors to closed position to open said valves, and by movement of the doors away from closed position to close said valves.
9. In a safety mechanism, the combination with a plurality of doors, of a Huid pressure operated indicating or control device, a Huid pressure conduit leading from a Source of supply to said device, a valve at each door,
and having one position for opening communie-ation through said conduit and another position for closing said communication and opening an exhaust from one section of said conduit, and means governed by the movement of the door to and from its l closed osition for operating said valves,
said va ves being located in the conduit be- ALBERT GOTTSCHALK.
US323657A 1919-09-13 1919-09-13 Safety mechanism for doors Expired - Lifetime US1479062A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US323657A US1479062A (en) 1919-09-13 1919-09-13 Safety mechanism for doors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US323657A US1479062A (en) 1919-09-13 1919-09-13 Safety mechanism for doors

Publications (1)

Publication Number Publication Date
US1479062A true US1479062A (en) 1924-01-01

Family

ID=23260149

Family Applications (1)

Application Number Title Priority Date Filing Date
US323657A Expired - Lifetime US1479062A (en) 1919-09-13 1919-09-13 Safety mechanism for doors

Country Status (1)

Country Link
US (1) US1479062A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2626003A (en) * 1950-04-14 1953-01-20 Henry A Kutzer Safety device for motor vehicles with automatic transmissions
US3697943A (en) * 1968-12-12 1972-10-10 Daimler Benz Ag Installation for indicating the closing condition of vehicle doors, especially of motor vehicle doors

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2626003A (en) * 1950-04-14 1953-01-20 Henry A Kutzer Safety device for motor vehicles with automatic transmissions
US3697943A (en) * 1968-12-12 1972-10-10 Daimler Benz Ag Installation for indicating the closing condition of vehicle doors, especially of motor vehicle doors

Similar Documents

Publication Publication Date Title
US1479062A (en) Safety mechanism for doors
US2485252A (en) Door operating fluid motor system
US1410289A (en) Car door and brake control equipment
US1309648A (en) James w
US1553615A (en) Motor-vehicle control mechanism
US1648215A (en) Angle cock
US2162423A (en) Locomotive sanding apparatus
US881706A (en) Automatic stop for railway-vehicles.
US1634119A (en) Automatic train-control device
US1412816A (en) graf and m
US1509951A (en) Brake and door control
US1522452A (en) Safety device for railways
US891675A (en) Pneumatic adjuster for angle-cocks on train-pipes.
US1694543A (en) Apparatus for operating and controlling the doors of tramway or like vehicles
US1736019A (en) Door and brake control device
US1515842A (en) Air-brake and safety car-control apparatus
US1133644A (en) Trip-valve device.
US959209A (en) Air-brake-testing system.
US1727371A (en) Sylvania
US1215952A (en) Automatic safety signaling and braking device for trains.
US1426893A (en) Safety car control and air-brake equipment
US1170862A (en) Train-stop.
US1717328A (en) Train control
US1345816A (en) Automatic train controlling and stopping mechanism
US998260A (en) Automatic train-stopping device.