Hydraulic Brake Lowering Control With Accumulator Pressure Buffering
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Solution Overview
Problem
Existing hydraulic lowering devices for lifting equipment are difficult to operate, causing stress and fatigue for operators, as they require adjusting pumping force and speed to balance fluid pressure in the brake's hydraulic chamber, leading to unpredictable and uncontrolled load lowering.
Innovation Solution
A hydraulic lowering device with a pressurized fluid accumulator, a pump, and a three-way pressure regulator, allowing for decoupling of pressurization and pressure adjustment, enabling controlled pressure regulation in the brake's hydraulic chamber for safe and gradual load lowering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hand-operated hydraulic pump is used to control brake release pressure, then the load can be lowered, but the operator must continuously adjust pumping force and speed to balance fluid pressure, causing stress and fatigue
Solution Approach 1:
A hydraulic accumulator is introduced as an intermediary device between the hand pump and the brake's hydraulic chamber. The accumulator stores pressurized fluid and provides a stable pressure source, decoupling the operator's pumping actions from the brake pressure control. This eliminates the need for continuous adjustment of pumping force and speed, reducing operator stress and fatigue while maintaining reliable control stability.
2Reliability
If pressure in the hydraulic chamber is controlled by matching pump flow to leakage rate, then fluid pressure can be maintained, but the lowering operation becomes difficult to control and unpredictable
Solution Approach 1:
The hydraulic accumulator serves as a mediator that decouples the pump flow control from the brake pressure control. By storing pressurized fluid, the accumulator provides a stable pressure source that is independent of the pump's instantaneous flow rate. This eliminates the difficulty of matching pump flow to leakage rate, making the lowering operation predictable and easy to control while maintaining reliable pressure control.
Solution Approach 2:
The accumulator is pre-charged with pressurized fluid before the lowering operation begins. This preliminary action ensures that when the lowering operation starts, there is already a stable reservoir of pressurized fluid available, eliminating the need for the operator to continuously adjust pumping parameters during the operation.
3Reliability
If the operator controls lowering from the lifting bridge or top of the crane, then the brake can be controlled, but the operator is in an uncomfortable and dangerous position at height
Solution Approach 1:
The control function is extracted from the high-position location (lifting bridge or top of crane) and relocated to ground level. The hydraulic accumulator and associated control components are positioned at ground level, allowing the operator to control the brake and lowering operation from a safe and comfortable position without being exposed to the dangers of working at height.
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 device allows for safe, controlled, and gradual lowering of loads, reducing operator stress and fatigue, as it enables precise pressure regulation and use from a comfortable, stable position, compatible with various safety brakes.
Implementation Method 1
a pressurized fluid accumulator, connected to the fluid reservoir
Implementation Method 2
a pump connected to the reservoir to inject pressurized fluid from the reservoir into the accumulator
Implementation Method 3
a three-way pressure regulator comprising a mechanical control input for setting a setpoint, a fluid inlet connected to the accumulator, a first fluid outlet connected to the fluid outlet port of the lowering device
Data Source
AI summary
A hydraulic lowering device for a safety brake of lifting equipment includes a fluid reservoir (1), a fluid outlet port (18), a pressurized fluid accumulator (2), a pump (3, 3′) connected to the fluid reservoir for injecting pressurized fluid from the fluid reservoir into the pressurized fluid accumulator, and a three-way pressure regulator (4) including a mechanical control input, actuated via a handwheel (5), for setting a setpoint value, a fluid inlet connected to the pressurized fluid accumulator (2), a fluid outlet connected to the fluid outlet port (18), and a drain connected to the fluid reservoir (1). The three-way pressure regulator (4) enables precise and completely safe control of the release, reinforcement and attenuation of braking. The dissociation between establishing, by pumping, a reserve of energy into the pressurized fluid accumulator (2) and controlling the lowering via the three-way pressure regulator (4) facilitates control.