GB1594555A - Pressure medium operated brake system - Google Patents

Pressure medium operated brake system Download PDF

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Publication number
GB1594555A
GB1594555A GB1276778A GB1276778A GB1594555A GB 1594555 A GB1594555 A GB 1594555A GB 1276778 A GB1276778 A GB 1276778A GB 1276778 A GB1276778 A GB 1276778A GB 1594555 A GB1594555 A GB 1594555A
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GB
United Kingdom
Prior art keywords
pressure
limiter
minimum
brake
brake cylinder
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
Application number
GB1276778A
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.)
KNORR BREMSE GmbH
Knorr Bremse AG
Original Assignee
KNORR BREMSE GmbH
Knorr Bremse AG
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 KNORR BREMSE GmbH, Knorr Bremse AG filed Critical KNORR BREMSE GmbH
Publication of GB1594555A publication Critical patent/GB1594555A/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T15/00—Construction arrangement, or operation of valves incorporated in power brake systems and not covered by groups B60T11/00 or B60T13/00
    • B60T15/02—Application and release valves
    • B60T15/18—Triple or other relay valves which allow step-wise application or release and which are actuated by brake-pipe pressure variation to connect brake cylinders or equivalent to compressed air or vacuum source or atmosphere
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T15/00—Construction arrangement, or operation of valves incorporated in power brake systems and not covered by groups B60T11/00 or B60T13/00
    • B60T15/02—Application and release valves
    • B60T15/36—Other control devices or valves characterised by definite functions
    • B60T15/48—Other control devices or valves characterised by definite functions for filling reservoirs
    • B60T15/50—Other control devices or valves characterised by definite functions for filling reservoirs with means for limiting or relieving pressure in reservoirs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
    • B60T17/18—Safety devices; Monitoring

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Braking Systems And Boosters (AREA)
  • Valves And Accessory Devices For Braking Systems (AREA)
  • Braking Arrangements (AREA)

Abstract

The air brake has an air supply reservoir (1), which is connected to a triple pressure control valve (19) by a feed line (2) by way of a maximum pressure limiter (4) and by feed line branches (8, 9) by way of brake nozzles (10) or a minimum pressure limiter (12). The brake nozzles (10) and the minimum pressure limiter (12) are connected parallel to one another and connected in series to the maximum pressure limiter (4). It is thereby ensured that the level of the pressure in the supply reservoir (1) cannot have an influence on the responsiveness of the triple pressure control valve (19). <IMAGE>

Description

(54) A PRESSURE MEDIUM OPERATED BRAKE SYSTEM (71) We, KNORR-BREMSE GmbH, Moosacher Strasse 80, D-8000 Munchen 40, Federal Republic of Germany, and a Cierman company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to a pressure medium operated brake system comprising a supply reservoir for pressure medium, a triple-pressure control valve for controlling the operation of a brake cylinder, a supply line extending between the reservoir and the control valve, and a maximum pressure limiter, a minimum pressure-limiter, and a throttle valve provided in the brake system for controlling the supply of pressure medium from the reservoir to the control valve.
It is known from German Offenlegungsschrift No. 2,015,006 and 2,533,783 to provide compressed air brake systems in which both the maximum pressure limiter and also the minimum pressure limiter are connected in parallel with each other in a portion of a feed line between a compressed air supply reservoir and the triple pressure control valve.
With this known arrangement, throttle valves which, subsequent to starting, determine the pressure increase velocity of the brake pressure, are arranged in series relative to the maximum pressure limiter in a section of the feed line which bridges the minimum pressure limiter. In these known arrangements, in the released condition and also in the event of braking operations up to termination of starting due to closure of the minimum pressure limiter, at braking pressure of for example 0.7 bar, the full pressure of the supply air reservoir in the triple pressure control valve is present upstream of the inlet valve thereof.
Subsequent to closure of the minimum pressure limiter, this pressure present in the triple pressure control valve is reduced by the maximum pressure limiter to the maximum brake pressure of for example 3.8 bar, and is introduced. This results in varying response sensitivities of the triple pressure control valve, since the inlet valve thereof, in the released condition and in the brake pressure zone or range, below the starting end pressure must open against the full supply reservoir pressure of for example 5 bar in the case of single-line brakes, 8-10 bar in the case of two-line brakes, but during further brake operation only against the maximum brake pressure of for example 3.8 bar, so that varying opening forces are required.Also the starting behaviour, the chronological brake-pressure development during starting, is influenced by the level of the feed pressure present in the triple pressure control valve, and varies in a manner which is undesirable, with the above-indicated, sometimes greatly varying pressures in the supply air reservoir. Additionally, at the end of starting, varying brake pressures may result, since the minimum-pressure limiter is subjected to the full supply air reservoir pressure and, as a function of the varying level thereof, may have varying closure pressures. These influences are undesirable and disadvantageous, since the characteristic of the triple pressure control valve is varied by the particular level of the supply-air reservoir pressure.
For at least partial obviation- of the above-described defects, it is already known to design the inlet valve of the triple pressure control valve to be pneumatically relieved of load. Thereby, however, supplementary structural outlay is required.
According to the invention there is provided a pressure medium operated brake system comprising: a supply reservoir for pressure medium; a triple-pressure control valve for controlling the operation of a brake cylinder; a supply line extending between said reservoir and said control valve; and a maximum pressure limiter, a minimum pressure limiter, and a throttle valve provided in the brake system for controlling the supply of pressure medium from said reservoir to said control valve; in which the minimum pressure limiter and the throttle valve are connected together in parallel with their inlets connected to an upstream portion of the supply line and their outlets connected to a downstream portion of the supply line;; and in which said maximum pressure limiter is connected to one of said portions of the supply line and in series with the parallel connection-together of the minimum pressure limiter and the throttle valve.
Thus, according to an embodiment of the invention, a pressure medium operated brake system is provided in which, without supplementary structural outlay, the level of the pressure in the supply reservoir cannot have any bearing on the response sensitivity of the triple pressure control valve. In the triple pressure control valve, there is present (in delayed fashion) always only a feed pressure which corresponds to the maximum brake pressure as set by the maximum pressure limiter, so that an inlet valve of the triple pressure control valve is openable against a constant pressure level.
According to a preferred arrangement, the maximum pressure limiter is provided in the upstream portion of the supply line i.e. a section of the supply line extending between the reservoir and a branch to the minimum pressure limiter or the throttle valve, so that without additional outlay it is possible to achieve the result that also at the minimum pressure limiter there is always present only the maximum braking pressure as set by the maximum pressure limiter, as constant pressure level. Thus, the minimum pressure limiter, uninfluenced by possible variation in pressure level present in the reservoir, always, on attaining a predetermined, unchanging braking pressure level, closes and terminates starting.
One embodiment of a pressure medium operated brake system according to the invention will now be described in detail, by way of example only, with reference to the accompanying diagrammatic drawing.
In the following description, a rail vehicle brake system is operated by compressed air as the pressure medium which operates the system. However, it should be appreciated that the invention is not limited to a brake system operated only by compressed air, and the invention contemplates the use of pressure media other than compressed air, e.g. other compressed gases or hydraulic liquids.
A supply air reservoir 1 which, in conventional manner (not shown) is filled with compressed air of, by way of example, approximately 5 bar in the case of singleline brakes, or for example 8-10 bar in the case of two-line brakes, is connected via an upstream section 2 of a supply line with the inlet 3 of a maximum pressure limiter 4 of conventional design. As conventional, the maximum pressure limiter 4 has a shut-off valve loaded in the closure direction by the pressure in its outlet 5, against the force of the spring 6, and monitoring passage of compressed air therethrough. From the outlet 5, a section 2 of the supply line extends further to a branch 7 from which two branch limbs 8 and 9 extend.The limb 8 extends to a throttle valve(s) 10 (adjustable in cross-section to correspond to the particular type of traction involved) optionally via a conventional tractor-type converting device (not shown). The limb 9 extends to the input 11 of a minimum pressure limiter 12 which is designed in known manner and has a shut-off valve monitoring its passage and loaded in the closure direction by a control inlet 13 subjected to the action of braking pressure, against the force of a spring 14. The outlet 15 of the minimum pressure limiter 12 and the outlet 16 of the throttle valve 10 are combined by means of a section 17 of the supply line and are connected to an inlet chamber 18 of a triple pressure control valve 19.The inlet chamber 18 is adapted to be connected, in conventional manner, by means of an inlet valve element 20, by a brake pressure chamber 21 of conventionally designed triple pressure control valve 19 (not shown in detail). From the brake control chamber 21, a pipeline 22 conveys the brake pressure, as monitored by the triple-pressure control valve 19, to a brake cylinder 23. A branch line 24 connects the pipeline 22 to the control inlet 13 of the minimum pressure limiter 12.
At the outlet 5 of the maximum pressure limiter 4 there always obtains, independent of the in any event higher pressure level present in the auxiliary air reservoir 1, the maximum brake pressure adapted to be introduced by the triple pressure control valve 19 into the brake cylinder 23 during full or high-speed braking operations, to which said brake pressure the maximum pressure limiter 4 is adjusted. Thus, this maximum brake pressure always and constantly flows to the inlet 11 of the minimum pressure limiter 12, so that the shut-off valve contained in the minimum pressure limiter 12 is always loaded by a constant pressure level. Consequently, the minimum pressure limiter 12 closes also on reaching an entirely specific pressure level, completely independently of the pressure level present in the supply air reservoir 1, in its control inlet 13. Via the section 17 of the feed line, it is further and always only the maximum brake pressure level which is fed to the inlet chamber 18 of the triple pressure control valve 19, so that there is present above the inlet valve element 20 thereof, again, always a constant pressure level independent of the pressure level obtaining in the supply air reservoir 1, so that the opening resistance of the inlet valve element 20 is always constant. Thus, the inlet valve element 20 cannot bring about any kind of varying response behaviour of the triple pressure control valve 19.Additionally, on opening of the inlet valve element 20, at the commencement of braking at the inlet valve element, 20, there is always a constant pressure difference, the result thereof being that there is always an identically occurring pressure build-up, independent of the pressure in the supply air reservoir 1, in the brake cylinder 23 during starting and up to attainment of the closure pressure of the minimum-pressure limiter 12.
By virtue of the fact that the minimum pressure limiter 12 is connected in parallel with the throttle valve 10, this means that, in the resting position, when the brakes are released (pressureless brake cylinder 23) and the inlet valve element 20 is closed, the high maximum pressure determined by the maximum pressure limiter 4 exists in the chamber 18. However, at the start of a braking action, i.e. when the inlet valve element 20 opens, this maximum pressure in the chamber 18 is discharged as a result of the high discharge of pressurised air to the brake cylinder 23 (where there is a sudden rise in pressure since the throttle valve 10 prevents a sufficient return of tliis pressure).When a predetermined minimum pressure is reached in the chamber 18, the minimum pressure limiter 12 opens and thus prevents the pressure in the chamber 18 falling below the minimum, since a sufficient quantity of air can flow back through it without being restricted by the throttle valve 10. The rapid rise in pressure in the brake cylinder 23 continues until the minimum pressure is reached. Finally, when the minimum pressure is exceeded in the chamber 18, after the brake cylinder 23 has been filled with the minimum pressure, the minimum pressure limiter 12 closes and further rise in pressure for the chamber 18 and the brake cylinder 23 is controlled by the throttle valve 10 i.e. it is temporarily delayed so that a retarded pressure rise now takes place in the brake cylinder 23.
The principle of providing a retarded further build-up of pressure, after reaching the minimum pressure, is generally known, and is described in more detail in German Offenlegungsschrift 2,015,006 and 2,533,783.
In the described embodiment of the invention, the result is achieved that the inlet valve element 20 cannot falsify the characteristic of the triple pressure control valve 19 due to varying pneumatic loading, that during the starting phase there is always an identical pressure build-up in the brake cylinder 23, and that the starting phase is always terminated due to closure of the minimum-pressure limiter 12, with precisely the same brake pressure level in the brake cylinder 23. During the further braking procedure, the maximum pressure limiter 4 and the throttle valve 10 operate in conventional and known manner, so that these procedures do not require to be described here.
Preferably (and as illustrated), the maximum pressure limiter 4 is provided in an upstream portion of the supply line 2, and in series connection to the parallel arrangement of the minimum pressure limited 12 and the throttle valve 10 (the latter having their outlets connected to a downstream portion of the supply line).
However, it is within the scope of the invention for the maximum pressure limiter 4 to be provided in the downstream portion of the supply line 2, and in series connection with the parallel arrangement of the minimum pressure limiter 12 and the throttle valve 10.
WHAT WE CLAIM IS: 1. A pressure medium operated brake system comprising: a supply reservoir for pressure medium; a triple-pressure control valve for controlling the operation of a brake cylinder; a supply line extending between said reservoir and said control valve; and a maximum pressure limiter, a minimum pressure limiter, and a throttle valve provided in the brake system for controlling the supply of pressure medium from said reservoir to said control valve; in which the minimum pressure limiter and the throttle valve are connected together in parallel with their inlets connected to an upstream portion of the supply line and their outlets connected to a downstream portion of the supply line; ; and in which said maximum pressure limiter is connected to one of said portions of the supply line and in series with the parallel connection-together of the minimum pressure limiter and the throttle valve.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. feed line, it is further and always only the maximum brake pressure level which is fed to the inlet chamber 18 of the triple pressure control valve 19, so that there is present above the inlet valve element 20 thereof, again, always a constant pressure level independent of the pressure level obtaining in the supply air reservoir 1, so that the opening resistance of the inlet valve element 20 is always constant. Thus, the inlet valve element 20 cannot bring about any kind of varying response behaviour of the triple pressure control valve 19.Additionally, on opening of the inlet valve element 20, at the commencement of braking at the inlet valve element, 20, there is always a constant pressure difference, the result thereof being that there is always an identically occurring pressure build-up, independent of the pressure in the supply air reservoir 1, in the brake cylinder 23 during starting and up to attainment of the closure pressure of the minimum-pressure limiter 12. By virtue of the fact that the minimum pressure limiter 12 is connected in parallel with the throttle valve 10, this means that, in the resting position, when the brakes are released (pressureless brake cylinder 23) and the inlet valve element 20 is closed, the high maximum pressure determined by the maximum pressure limiter 4 exists in the chamber 18. However, at the start of a braking action, i.e. when the inlet valve element 20 opens, this maximum pressure in the chamber 18 is discharged as a result of the high discharge of pressurised air to the brake cylinder 23 (where there is a sudden rise in pressure since the throttle valve 10 prevents a sufficient return of tliis pressure).When a predetermined minimum pressure is reached in the chamber 18, the minimum pressure limiter 12 opens and thus prevents the pressure in the chamber 18 falling below the minimum, since a sufficient quantity of air can flow back through it without being restricted by the throttle valve 10. The rapid rise in pressure in the brake cylinder 23 continues until the minimum pressure is reached. Finally, when the minimum pressure is exceeded in the chamber 18, after the brake cylinder 23 has been filled with the minimum pressure, the minimum pressure limiter 12 closes and further rise in pressure for the chamber 18 and the brake cylinder 23 is controlled by the throttle valve 10 i.e. it is temporarily delayed so that a retarded pressure rise now takes place in the brake cylinder 23. The principle of providing a retarded further build-up of pressure, after reaching the minimum pressure, is generally known, and is described in more detail in German Offenlegungsschrift 2,015,006 and 2,533,783. In the described embodiment of the invention, the result is achieved that the inlet valve element 20 cannot falsify the characteristic of the triple pressure control valve 19 due to varying pneumatic loading, that during the starting phase there is always an identical pressure build-up in the brake cylinder 23, and that the starting phase is always terminated due to closure of the minimum-pressure limiter 12, with precisely the same brake pressure level in the brake cylinder 23. During the further braking procedure, the maximum pressure limiter 4 and the throttle valve 10 operate in conventional and known manner, so that these procedures do not require to be described here. Preferably (and as illustrated), the maximum pressure limiter 4 is provided in an upstream portion of the supply line 2, and in series connection to the parallel arrangement of the minimum pressure limited 12 and the throttle valve 10 (the latter having their outlets connected to a downstream portion of the supply line). However, it is within the scope of the invention for the maximum pressure limiter 4 to be provided in the downstream portion of the supply line 2, and in series connection with the parallel arrangement of the minimum pressure limiter 12 and the throttle valve 10. WHAT WE CLAIM IS:
1. A pressure medium operated brake system comprising: a supply reservoir for pressure medium; a triple-pressure control valve for controlling the operation of a brake cylinder; a supply line extending between said reservoir and said control valve; and a maximum pressure limiter, a minimum pressure limiter, and a throttle valve provided in the brake system for controlling the supply of pressure medium from said reservoir to said control valve; in which the minimum pressure limiter and the throttle valve are connected together in parallel with their inlets connected to an upstream portion of the supply line and their outlets connected to a downstream portion of the supply line; ; and in which said maximum pressure limiter is connected to one of said portions of the supply line and in series with the parallel connection-together of the minimum pressure limiter and the throttle valve.
2. A brake system according to claim 1,
in which the maximum pressure limiter is provided in said upstream portion of the supply line.
3. A brake system according to claim I or 2, and including a brake cylinder in fluid connection with said control valve.
4. A brake system according to any one of the preceding claims, in which said supply reservoir comprises a reservoir for compressed air and said system is adapted for operation by compressed air.
5. A rail vehicle having a brake system according to any one of the preceding claims.
GB1276778A 1977-04-01 1978-03-31 Pressure medium operated brake system Expired GB1594555A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19772714723 DE2714723C2 (en) 1977-04-01 1977-04-01 Air brakes for rail vehicles

Publications (1)

Publication Number Publication Date
GB1594555A true GB1594555A (en) 1981-07-30

Family

ID=6005431

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1276778A Expired GB1594555A (en) 1977-04-01 1978-03-31 Pressure medium operated brake system

Country Status (5)

Country Link
AT (1) AT374751B (en)
CH (1) CH627980A5 (en)
DE (1) DE2714723C2 (en)
FR (1) FR2385569A1 (en)
GB (1) GB1594555A (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5779324A (en) * 1995-12-28 1998-07-14 Commercial Intertech Corp. Towed vehicle brake system
DE19702563C1 (en) * 1997-01-24 1998-08-06 Knorr Bremse Systeme Brake system for rail vehicle
DE19718098C2 (en) * 1997-04-29 2001-11-22 Knorr Bremse Systeme Braking system for rail vehicles
DE102012013524A1 (en) * 2012-07-06 2014-01-09 Knorr-Bremse Systeme für Schienenfahrzeuge GmbH Control valve with minimum pressure limitation
AT521879B1 (en) * 2018-10-16 2021-11-15 Siemens Mobility Austria Gmbh Pneumatic brake for a rail vehicle

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1090701B (en) * 1958-02-11 1960-10-13 Knorr Bremse Gmbh Monitoring device for rapid brake accelerators of compressed air brake systems for rail vehicles
FR1380516A (en) * 1963-09-06 1964-12-04 Westinghouse Freins & Signaux Method for converting an electro-pneumatic braking installation of the automatic type into an electro-pneumatic braking installation of the direct type and device for carrying out this method
DE1287105B (en) * 1968-01-26 1969-01-16 Knorr Bremse Gmbh Control valve for air brakes, especially for rail vehicles
DE2423430B2 (en) * 1974-05-14 1976-11-25 Knorr-Bremse GmbH, 8000 München CONTROL VALVE FOR COMPRESSED AIR BRAKES, IN PARTICULAR FOR RAIL VEHICLES

Also Published As

Publication number Publication date
CH627980A5 (en) 1982-02-15
AT374751B (en) 1984-05-25
FR2385569A1 (en) 1978-10-27
DE2714723C2 (en) 1979-04-19
ATA227778A (en) 1983-10-15
DE2714723B1 (en) 1978-08-17
FR2385569B1 (en) 1983-10-07

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Legal Events

Date Code Title Description
PS Patent sealed
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee