Tractor Brake Arrangement Series Valve Segmentation
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Solution Overview
Problem
Existing brake arrangements for tractors with cardan and separate rear brakes suffer from reliability issues due to switch valve wear, leading to unintended activation of the front brake when only one rear brake is intended to be applied, posing safety risks, especially at high speeds.
Innovation Solution
A brake arrangement with separate levers for left and right rear brakes and a cardan brake, where the cardan brake is connected to a series circuit of first and second brake valves, ensuring that the cardan brake is not activated when only one lever is pressed, using relay valves and control valves to manage fluid supply and prevent accidental activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switch valve is used to activate the front brake when both rear brakes are applied, then the front brake can be activated together with both rear brakes, but the switch valve suffers from wear and tear and may start to open under lower pressures, leading to unintended activation of the front brake
Solution Approach 1:
The circuit is divided into two separate series-connected brake valves (first brake valve and second brake valve) instead of using a single switch valve. Each valve is controlled by its own lever, creating segmented control paths that prevent unintended activation. The front brake circuit is split into two independent series paths, so both paths must be activated simultaneously to open both valves and allow fluid flow to the front brake.
Solution Approach 2:
Two brake valves are introduced as intermediary control elements between the fluid supply and the front brake. These valves act as mediators that must both be opened simultaneously (by pressing both levers) to allow fluid flow to the front brake. This intermediary control mechanism eliminates the wear and reliability issues of a single switch valve while maintaining the capability to activate the front brake when needed.
2Ease of operation
If both levers are connected to activate the cardan brake through a single switch valve, then the front brake can be activated, but safety issues arise when the valve opens prematurely due to wear, causing unintended front brake activation during steering maneuvers
Solution Approach 1:
The single switch valve control is segmented into two separate brake valves arranged in series. Each valve responds to its own lever, creating two independent control paths. This segmentation ensures that unintended activation of one valve does not activate the front brake, as both valves must be open simultaneously for fluid flow to reach the front brake.
Solution Approach 2:
The series arrangement of two brake valves provides a protective buffer against premature activation. Even if one valve wears and opens at lower pressure, the second valve remains closed and blocks fluid flow to the front brake. This prior protective measure prevents harmful unintended activation while maintaining normal brake control functionality.
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 reliable and safe operation by preventing the cardan brake from being activated when only one rear brake is intended to be applied, thereby enhancing safety and steering control without inadvertently engaging the front brake.
Implementation Method 1
the cardan brake is connected to a fluid supply in a circuit comprising a first and a second brake valve arranged in series
Implementation Method 2
said valve being a relay valve connected in series with the first and second brake valves
Implementation Method 3
the left brake is connected to a fluid supply and activated by a left brake valve and wherein the right brake is connected to the fluid supply and activated by a right brake valve, said left and right brake valves connected in parallel
Data Source
Figure 1
Figure 2
AI summary
A brake arrangement for a vehicle having a cardan brake 3 and separate left and right brakes 2L, 2R. The left brake 2L activated by movement of a first lever 4L and the right brake 2R is activated by movement of a second lever 4R. The left brake 2L, right brake 2R and the cardan brake 3 are activated together by movement of both levers 4L, 4R together, characterised in that the cardan brake 3 is connected to a fluid supply 5 in a circuit which comprises a first and a second brake valve 7, 8 arranged in series and the first brake valve 7 is operable by the first lever 4L and the second brake valve 8 is operable by the second lever 4R.