US3656632A

US3656632A - Hydropneumatic absorbing device for railway rolling stock

Info

Publication number: US3656632A
Application number: US27796A
Authority: US
Inventors: Zaven Oganezovich Karakashian; Vsevolod Arutjunovich Lazarian; Boris Vasilievich Azarov; Mikhail Mikhailovich Bolotin; Vladimir Yakovlevich Pershin; Albert Isidorovich Timoshuk; Anatoly Alexandrovi Dragonenko; Ilia Yakovlevich Zarakhovich; Mikhail Vasilievich Svidirov
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-03-11
Filing date: 1970-04-13
Publication date: 1972-04-18
Anticipated expiration: 1989-04-18
Also published as: GB1306292A; FR2048364A5

Abstract

A hydropneumatic absorbing device used in a railway rolling stock, comprising a cylinder having a movable cylinder mounted at the open end thereof and accommodating a floating piston and connected with a piston provided with through openings. Secured near the bottom of the cylinder is a partition forming together with the piston a space to be filled with working liquid, and together with the bottom of the cylinder - an additional chamber accommodating an additional piston. The partition is provided with through openings through which the working liquid is supplied into the additional chamber and displaces the additional piston. The spaces adjacent to the bottoms of the two cylinders are filled with compressed gas and the pressure in one of the spaces is several times greater than the pressure in the other space.

Description

United States Patent Karakashian et al.

1151 3,656,632 1451 Apr. 18, 1972 [54] HYDROPNEUMATIC ABSORBING DEVICE FOR RAILWAY ROLLING STOCK [22] Filed: Apr. 13,1970

[21] Appl.No.: 27,796

[52] U.S.Cl .213/43, 188/317,213/223, 267/64 R, 188/316 151] mu ..B61g9/l6,B61g 11/12 [58] Field of Search ..213/8, 43, 223; 267/64 R, 43, 267/64 A; 188/313, 316, 317, 321

Primary Examiner-Drayton E. Hofiman Attorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A hydropneumatic absorbing device used in a railway rolling stock, comprising a cylinder having a movable cylinder mounted at the open end thereof and accommodating a floating piston and connected with a piston provided with through openings. Secured near the bottom of the cylinder is a partition fonning together with the piston a space to be filled with working liquid, and together with the bottom of the cylinder an additional chamber accommodating an additional piston. The partition is provided with through openings through which the working liquid is supplied into the additional chamber and displaces the additional piston. The spaces adjacent to the bottoms of the two cylinders are filled with compressed gas and the pressure in one of the spaces is several times greater than the pressure in the other space.

3 Claims, 6 Drawing Figures PATENTEU APR 1 8 I972 SHEET 1 [IF 3 'PATENTEU APR 1 81912 SHEET 3 [1F 3 I-IYDROPNEUMATIC ABSORBING DEVICE FOR RAILWAY ROLLING STOCK BACKGROUND 1. Field of the Invention This invention relates to hydropneumatic devices for absorbing kinetic energy of relatively movable bodies and more particularly automatic couplers for railway rolling stock.

2. Description of the Prior Art Known in the art are hydropneumatic absorbing devices provided with a cylinder which accommodates another movable cylinder of a smaller diameter, disposed at the open side thereof, the bottom of the latter cylinder interacting with the movable portion of an automatic coupling of'a railway rolling stock. The movable cylinder accommodates a floating piston disposed inside thereof, and at its open side is connected with a piston having through openings, for the working liquid to flow from the space disposed between the bottom of said piston and a partition secured in the cylinder near the bottom thereof, into a space disposed at the other side of the piston. Provided between the partition and the bottom of the cylinder is an additional chamber accommodating an additional piston, the latter being displaced by meansof a hollow rod connected therewith and interacting with a piston connected with the movable cylinder in the course of movement of the latter.

The space confined between the bottom of the cylinder and the additional piston, as well as the spacedisposed between the bottom of the movable cylinder and the floating piston, are filled with compressed gas. The pressure of the compressed gas in the space disposed between the cylinder bottom and the additional piston by several times exceeds the pressure of the compressed gas contained in the space confined by the bottom of the movable cylinder and the floating piston.

To protect the cylinder from excessive pressure, the device is provided with a safety valve arranged in the hollow rod. During its return stroke the movable cylinder is braked by means of a throttle valve (see, for example, U.S. Pat. No. 3,l93,1 12; July 6, 1965).

With the longitudinal force preset, the absorbing capacity of the hydropneumatic absorbing device depends directly upon the stroke of the piston connected with the movable cylinder of the device. In the afore-described hydropneumatic absorbing device the piston stroke equals 70 mm., and its absorbing capacity is equal to l0,000-l2,000 kgm, which, with the preset longitudinal force equalling 200 tons, provides for the absorption of the kinetic energy of collision of four-axle cars moving at a speed of 12 km/hr.

Such absorbing capacity proves insufficient to damp the kinetic energy of collision of six axle cars moving at the aforesaid speed, or of collision of four-axle cars moving at speeds considerably exceeding 12 km/hr.

SUMMARY OF THE INVENTION The main object of the invention is the provision of a hydropneumatic absorbing device that possesses a greater absorbing capacity owing to an increased stroke of the movable cylinder, the overall dimensions of the device and the allowable longitudinal force being the same.

This object is accomplished in a hydropneumatic absorbing device used in a railway rolling stock and comprising a cylinder having a movable cylinder disposed at the open side thereof and accommodating a floating piston, said movable cylinder interacting with the movable parts of the automatic coupling, being connected with a piston provided with through openings overlapped by a throttle valve during the piston return stroke, a partition being secured near the bottom of the cylinder, together with the piston said partition forming a space filled with working liquid and together with the bottom of the cylinder said partition forming an additional chamber, accommodating an additional piston which moves during the movement of the movable cylinder, the spaces adjacent to the bottoms of the cylinders being filled with compressed air, the pressure of the air in one space exceeding by several times the pressure of the air in the other space; according to the present invention, the partition is provided with openings to communicate the space filled with the working liquid with the additional chamber, and the additional piston is made floating.

It is expedient to secure a rod on the partition along the cylinder axis, said rod having a cross section decreasing towards its free end portion and passing through the opening in the piston, thus controlling the discharge of the working liquid through this opening.

Such a control of the discharge of the working liquid provides for a still greater absorbing capacity of the hydropneumatic absorbing device.

The hydropneumatic absorbing device in accordance with the present invention, possesses an absorbing capacity of up to 20,000 kgm, which makes it possible to absorb the kinetic energy produced by the collision of four-axle cars moving at a speed of up to km/hr, or by the collision of six axle cars 0 moving at a speed of up to 16 km/hr, the allowable longitudinal force being equal to 200 tons.

BRIEF DESCRIPTION OF THE DRAWING The following description of a specific exemplary embodiment of the present invention is given with reference to the accompanying drawings in which:

FIG. 1 is a longitudinal section of a hydropneumatic absorbing device, according to the present invention;

FIG. 2 is a prespective view of a rod used for controlling the discharge of the working liquid;

FIG. 3 is a sectional view showing the disposition of the device members at the beginning of the working stroke;

FIG. 4 is a view similar to FIG. 4 in the intermediate position of the working stroke; and

FIG. 5 is a view similar to FIG. 4 at the beginning of the return stroke; and

FIG; 6 is a graph of the operation of the hydropneumatic absorbing device.

DETAILED DESCRIPTION The hydropneumatic absorbing device comprises a cylinder 1 having a movable cylinder 2 mounted at the open side thereof, the bottom of the movable cylinder 2 interacting with movable parts of an automatic coupling device (not shown in the drawing). 0n the outer surface of the movable cylinder 2 are grooves accommodating packing rings 4 and bronze inserts 5. Disposed inside the movable cylinder 2 is a floating piston 6 having rubber packing rings 7 and a hydraulic packing which consists of a small piston 8 housed in a chamber 9 filled with oil and communicating via passages 10 with annular grooves 11 on the outer surface of the floating piston 6.

The side of the movable cylinder 2, opposite to the bottom 3 is rigidly connected with a piston 12 having through openings 13 and a central opening 14.

The piston 12 is provided with an annular recess 15 accommodating a throttle valve 16 used to overlap the openings 13 during the return stroke of the piston 12. The displacement of the throttle valve 16 is limited by a ring 17.

Rigidly secured in the cylinder 1 near its bottom 18 is a partition 19 which together with the piston 12 forms a space 20 filled with working liquid introduced through an opening in the cylinder 1 and closed by a plug 21. The partition 19 forms an additional chamber 22 with the bottom 18 of the cylinder 1. This chamber accommodates an additional piston 23 with packing rings 24, the additional piston 23 being made floating.

The partition 19 is provided with openings 25 communicating the additional chamber 22 with the space 20.

Secured in the middle portion of the partition 19 is a rod 26 having a varying cross section decreasing towards its free end, said rod passing through the central opening 14 in the piston 12.

The varying cross section of the rod 26 is obtained due to the fact that the rod has four slots 27 (FIG. 2) therein having the same width, the depth of the slots decreasing in the direction towards the secured end portion of the rod.

The body of the rod 26 accommodates a safety valve 28 (FIG. 1) which, in case the pressure of the liquid exceeds an allowable value, communicates the space 20 with a space disposed between the piston 12 and the floating piston 6.

The space 29 disposed in the movable cylinder 2 between the bottom 3 thereof and the floating piston 6 is filled with compressed gas supplied via a valve 30, the pressure of the gas being approximately equal to 50 kg/cm A space 31 disposed between the bottom 18 of the cylinder 1 and the additional piston 23 is filled via a valve 32 with compressed gas under the pressure of 15 kglcm The hydropneumatic absorbing device functions as follows:

When two cars collide, the movable parts of the automatic coupling (not shown in the drawing) interact with the bottom 3 of the movable cylinder 2 by moving it inside the cylinder 1. The piston 12 connected with the cylinder 2, moves together with the latter and forces the working liquid out of the space 20 into the additional chamber 22, as shown in FIG. 3, since the pressure of the compressed gas in the space 31 is considerably smaller than that of the compressed gas contained in the space 29. The working liquid flows from the space 20 into the additional chamber 22 until the additional piston 23 displaced by the liquid thrusts against the bottom 18 of the cylinder 1.

During further movement of the piston 12, the working liquid starts flowing via the openings 13 in the piston 12 and via the slots 27 of the rod 26 into a space 33 formed between the piston 12 and the floating piston 6, as shown in FIG. 4, and displaces the floating piston 6.

The working liquid continues to flow in the afore-described manner until the piston 12 reaches the partition 19 and all the working liquid flows into the space 33. The length of the complete stroke of the piston is 120 mm.

The employment of the rod 26 having a varying cross section is necessary to maintain a required hydraulic resistance of the working liquid when the rate of the piston 12 displacement is decreased.

The return stroke of the piston 12 starts only when the force exerted by the movable parts of the automatic coupling (not shown in the drawing) upon the bottom 3 of the movable cylinder 2 is smaller than the total force of the compressed gas in the

spaces

31 and 29.

The

floating pistons

6 and 23 and the piston 12 are retracted in reverse order from that previously described, as shown in FIG. 5, under the action of the compressed gas contained in the

spaces

31 and 29. During this stroke the throttle valve 16 under the pressure of the working liquid closes the through openings 13 having constant cross sections, which contributes to the retarded motion of the piston 12 during its return stroke.

In order to limit the displacement of the movable cylinder 2 during its return stroke, the cylinder 1 is provided with a stop I 34 fashioned as a nut.

The diagram shown in FIG. 6 shows the variation of force Q (longitudinal force) depending on stroke S of the piston.

Line a shows changes of the force during the compression of the gas in the space 31; line b shows changes of the force Q, when the gas contained in the space 29 is slowly compressed, and line c shows changes of this force during the gas dynamic compression which takes place in accordance with the adiabatic conditions with a polytropic index of ll.3; line d shows changes in the dynamic resistance of the liquid.

In the zone 0-1 the liquid flows from the space 20 into the additional chamber 22, the gas contained in the space 31 is compressed, and line a shows in the diagram changes of the force Q during the compression of the gas in this space.

At the point 1 the space 29 is actuated, line c showing in the diagram the change of the force 0 during the compression of thelglas in this space.

e dynamic force rises up to point II. At this time the speed of movement starts decreasing, however, due to the dynamic force of the compressed gas in the space 29 and an increase in the hydraulic resistance of the liquid taking place while the latter is flowing out through decreasing cross-sections of the slots 27 of the rod 26, the characteristic is equalized before the point III, and the changes in the total hydrodynamic force are characterized by a curve shown by line e. Thus, the efficient operation of the hydropneumatic absorbing device is provided in the course of its whole movement.

In the diagram, shown in FIG. 6, the cross hatched area at the left shows the operation of the hydropneumatic absorbing device used to damp impacts, with a piston stroke equalling 70 mm, whereas the additional shows an additional increase in the absorbing capacity of the proposed device taking place due to its greater length increased up to 120 mm and to the employment of the rod having a varying cross-section.

The hydropneumatic absorbing device according to the present invention provides for an increased absorbing capacity of up to 20,000 kgm, which allows shunting operations with cars having a speed of collision of up to 20 km/hr.

Furthermore, this embodiment of the hydropneumatic absorbing device provides for damping of multiple shocks and impacts developed when a train starts moving, is moving along a prolonged slope, or is braked.

What is claimed is:

1. A hydro-pneumatic absorbing device for absorbing kinetic energy of bodies having relative motion and particulady for automatic couplers for railway rolling stock, said device comprising a first cylinder having open and closed ends; a movable cylinder adapted for engaging the movable parts of an automatic coupling of the rolling stock, said movable cylinder being slidable in said first cylinder at said open end thereof; said movable cylinder having a closed end projecting from the open end of the first cylinder; a floating piston disposed in said movable cylinder; a second piston provided with through openings rigidly connected with said movable cylinder; a throttle valve disposed in said second piston and overlapping said through openings during piston return stroke; a partition provided with through openings, said partition being secured in said first cylinder near the closed end thereof and forming together with said second piston a chamber adapted to be filled with working liquid and together with the closed end of said first cylinder an additional chamber; and an additional floating piston disposed in said additional chamber and being displaced in the course of movement of said movable cylinder, said additional floating piston defining a space with the closed end of the first cylinder, the first floating piston defining a space with the closed end of the movable cylinder, said spaces being filled with compressed gas, the pressure of the gas in one of the spaces exceeding by several times the pressure in the other space.

2. A hydropneumatic absorbing device as claimed in claim 1 comprising a rod secured to said partition and extending along the axis of the cylinder, said rod having a varying cross section which decreases in a direction away from said partition, said second piston having an opening in which said rod travels and controls discharge of the working liquid through said opening.

3. A hydropneumatic absorbing device as claimed in claim 2 wherein said rod has a passageway for providing communication between the chamber filled with working liquid and the opening in the second piston, and a safety valve in said passageway.

Claims

1. A hydro-pneumatic absorbing device for absorbing kinetic energy of bodies having relative motion and particularly for automatic couplers for railway rolling stock, said device comprising a first cylinder having open and closed ends; a movable cylinder adaptEd for engaging the movable parts of an automatic coupling of the rolling stock, said movable cylinder being slidable in said first cylinder at said open end thereof; said movable cylinder having a closed end projecting from the open end of the first cylinder; a floating piston disposed in said movable cylinder; a second piston provided with through openings rigidly connected with said movable cylinder; a throttle valve disposed in said second piston and overlapping said through openings during piston return stroke; a partition provided with through openings, said partition being secured in said first cylinder near the closed end thereof and forming together with said second piston a chamber adapted to be filled with working liquid and together with the closed end of said first cylinder an additional chamber; and an additional floating piston disposed in said additional chamber and being displaced in the course of movement of said movable cylinder, said additional floating piston defining a space with the closed end of the first cylinder, the first floating piston defining a space with the closed end of the movable cylinder, said spaces being filled with compressed gas, the pressure of the gas in one of the spaces exceeding by several times the pressure in the other space.