Rail Brake Cylinder Locking Device for Emergency Release

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Solution Overview

Problem

Existing brake cylinder designs for rail vehicles lack a reliable mechanical locking mechanism that ensures permanent emergency release and low emergency release forces, posing safety risks during pad changes and towing without compressed air supply.

Innovation Solution

A brake cylinder with a locking device featuring a control piston and emergency release plunger, where the emergency release state is permanently locked outside the power flow, using a locking pin to ensure complete release before re-engagement, and a non-self-locking thread with pawls to reduce wear and space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the emergency release pin is located in the power flow of the piston force, then the emergency release state can be permanently locked, but a high emergency release force is required due to friction on the pin

Engineering Contradiction:
Improvepermanent locking of emergency release stateVSAvoidemergency release force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The emergency release plunger is extracted from the power flow of the service brake piston, placing it in a separate control pressure chamber. This separation removes the frictional resistance that would otherwise be present in the power flow path, allowing emergency release with lower forces while maintaining permanent locking capability through the dedicated control mechanism

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If the emergency release device acts directly on the control piston, then the structure is simpler, but the emergency release state is not permanently locked and the release process completion cannot be ensured

Engineering Contradiction:
Improvestructure simplicityVSAvoidpermanent assurance of release state
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The brake cylinder is segmented into functionally independent control chambers: the service brake pressure chamber and the control pressure chamber. The emergency release plunger operates in the control pressure chamber with its own dedicated control mechanism, ensuring permanent locking of the emergency release state while maintaining structural clarity through functional separation

Inventive Principle:
Principle #1Segmentation

3Reliability

If a locking mechanism with high friction is used to ensure permanent emergency release locking, then reliability is improved, but the emergency release force requirement increases

Engineering Contradiction:
Improvepermanent emergency release lockingVSAvoidemergency release force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

A dedicated control pressure chamber acts as an intermediary mechanism between the emergency release plunger and the locking mechanism. This intermediary allows the emergency release state to be permanently locked through pressure-controlled actuation rather than direct high-friction mechanical engagement, significantly reducing the force required for emergency release while maintaining reliable permanent locking

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution ensures secure locking against unintentional rolling, permanent assurance of locking force, and lower emergency release forces, allowing safe manual deactivation and compact design.

Implementation Method 1

a service brake piston (2) which can be moved axially within a housing (1a), which can be moved by being acted upon by a pressure medium

Methodology Applied
Scientific EffectPressure medium actuation: Pressure Increase

Implementation Method 2

the piston tube (5) having a non-self-locking thread which engages with a threaded nut (7) rotatably mounted in the housing

Methodology Applied
Scientific EffectThreaded engagement: Screw

Implementation Method 3

the locking device interacting with a toothing (8) of the threaded nut (7) comprises one or more pawls (11, 12)

Methodology Applied
Scientific EffectMechanical locking: Ratchet

Implementation Method 4

a spring accumulator which can be released by a control piston and which can act on a piston rod

Methodology Applied
Scientific EffectSpring energy storage: Spring

Data Source

PatentEP3849863B1Brake cylinder with locking device for mechanically locking the brake force
Publication Date: 2023.04.26 KNORR BREMSE SYST FUR SCHIENENFAHRZEUGE GMBH
  • EP3849863B1 patent drawingFigure 1
  • EP3849863B1 patent drawingFigure 2
  • EP3849863B1 patent drawingFigure 2a

AI summary

The invention relates to a brake cylinder (1) comprising a locking device (10) for mechanical brake force locking, in particular for rail vehicles, and comprising a service brake piston (2) which can be axially moved inside a housing (1), which can be moved by applying a pressure medium thereto, and which is coupled to a piston tube (5), said piston tube (5) being provided with a non-self-locking thread (9) which is engaged with a threaded nut (7) which is rotatably mounted in the housing (1), and the locking device (10) cooperating with toothing (8) of the threaded nut (7). The brake cylinder is designed such that the locking device (10) comprises one or more pawl(s) (11, 12), a control piston (13), an emergency release tappet (14), and a locking element (17) of the emergency release tappet (14).