Bascule Bridge Span Lock Wear Reduction via Periodic Hydraulic Actuation
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Solution Overview
Problem
Existing wear compensating energy-absorbing span lock systems require continuous hydraulic pressure to maintain contact between shoes and locking bars in bascule bridges, leading to increased power consumption and wear, especially in less maintained environments.
Innovation Solution
Incorporating hydraulic actuators that separate the shoes from the lockbar only during opening and closing phases, eliminating the need for continuous power and reducing sliding friction, thus minimizing wear and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous hydraulic pressure is applied to maintain contact between shoes and locking bar, then contact pressure is maintained, but power consumption increases
Solution Approach 1:
The hydraulic pressure is applied periodically only during bridge opening and closing operations when the lockbar needs to be retracted, rather than continuously. The system uses hydraulic actuators to separate the shoes from the lockbar temporarily during these phases, then allows spring pressure to maintain contact when the bridge is locked and stationary, eliminating the need for continuous power consumption.
Solution Approach 2:
The spring-loaded shoes automatically maintain contact pressure with the lockbar without requiring continuous external power. The elastic potential energy stored in the springs provides self-sustaining contact force during normal locked operation, and the system self-activates hydraulic pressure only when operational movement is required.
2Reliability
If continuous hydraulic pressure is applied to maintain contact between shoes and locking bar, then contact pressure is maintained, but wear increases
Solution Approach 1:
Hydraulic pressure is applied periodically only during opening and closing phases when relative motion occurs, rather than continuously. During stationary locked operation, spring pressure maintains contact without hydraulic intervention, reducing the time that sliding friction acts on the components and thereby minimizing wear.
Solution Approach 2:
The patent converts the potentially harmful continuous sliding friction into a beneficial periodic action. By using springs to maintain contact pressure without continuous hydraulic pressure, the system allows minimal wear during stationary periods while ensuring reliable contact, and only applies hydraulic pressure during necessary movement phases when some wear is unavoidable but minimized compared to continuous pressure.
3Object-generated harmful factors
If hydraulic pressure is used to press shoes into firm contact with lockbar, then wear is reduced, but device complexity increases
Solution Approach 1:
The spring-loaded shoe mounting assembly provides automatic wear compensation without complex control systems. The springs self-adjust to maintain optimal contact pressure, and the hydraulic actuators are only activated automatically when bridge opening or closing is required, eliminating the need for complex continuous pressure regulation systems.
Solution Approach 2:
The patent extracts the hydraulic pressure function from being a continuous maintenance system and restricts it to only the specific phases when lockbar retraction is needed. This separation reduces the overall system complexity by eliminating continuous hydraulic control while retaining the benefits of hydraulic pressure where absolutely necessary.
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
This solution reduces wear on bridge components, minimizes energy required for operation, and achieves substantial power savings by only using hydraulic pressure when necessary, effectively addressing the challenges of maintaining contact pressure in hostile environments.
Implementation Method 1
incorporating with the resilient shoe mounting assembly a hydraulic actuator or expander that functions only to unload the shoes to enable the lockbar to be retracted prior to opening the span
Implementation Method 2
Resilient elements are illustrated as Bellville-washer type springs that engage shoes which bear on the end portion of the locking bars to effect the desired resilient connection
Data Source
AI summary
A wear resisting span lock system for bascule bridges includes a normally-inactive hydraulic lockbar shoe expander operable to minimize sliding engagement of the lockbar with its guiding and receiving shoes only during bridge opening and closing operations.