Ram Piston Overload Assembly With Additive Burst Disc Loading
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Solution Overview
Problem
Existing hydraulic tools face issues with burst discs experiencing reduced sealing force and fatigue due to opposing hydraulic pressure reaction forces and supporting forces, leading to leakage and reduced lifespan, and misalignment of lock nut and spacer components causing radial imbalance in sealing.
Innovation Solution
The integration of an overload assembly within the ram piston, where hydraulic pressure reaction force and supporting force act additively on the burst disc, utilizing a spacer and lock nut configuration with aligned radial surfaces to maintain consistent sealing, and optionally incorporating a ball for universal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lock nut and spacer are positioned to counter hydraulic pressure reaction force on the burst disc, then the burst disc can withstand high pressure, but the sealing force on the burst disc decreases and leakage occurs
Solution Approach 1:
The invention inverts the traditional force balance approach by making the lock nut and spacer work together to create additive forces on the burst disc. Instead of the lock nut counteracting the hydraulic pressure, both the hydraulic pressure reaction force and the lock nut supporting force now act in the same direction to enhance sealing, resolving the contradiction between pressure resistance and sealing reliability.
Solution Approach 2:
The invention merges the functions of the lock nut and spacer into a unified force system. The lock nut is positioned to engage with the spacer such that their combined forces are additive rather than opposing. This merging of force vectors ensures both high pressure resistance and reliable sealing by making the forces work together toward the same objective.
2Reliability
If the supporting force on the burst disc is increased to prevent leakage, then sealing improves, but the fatigue life of the burst disc decreases
Solution Approach 1:
The invention applies partial action by using the spacer to distribute the supporting force over a larger area of the burst disc. Instead of concentrating excessive force at a single point, the spacer spreads the load, providing sufficient sealing force while reducing localized stress that would accelerate fatigue and extend the burst disc's service life.
3Ease of manufacture
If the lock nut and spacer are not precisely aligned, then assembly is easier, but radial imbalance occurs causing misalignment and sealing issues
Solution Approach 1:
The invention employs spherical or curved surfaces on the lock nut and spacer components that provide self-aligning characteristics. These curved surfaces allow the components to automatically find their correct alignment position during assembly, eliminating the need for precise pre-alignment while ensuring proper radial alignment and sealing contact.
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
Enhances burst disc sealing at higher pressures, prolongs its lifespan, and maintains consistent sealing force, reducing leakage and misalignment issues, thus improving the hydraulic tool's operational reliability.
Implementation Method 1
A hydraulic pump pressurizes hydraulic fluid and transfers it to a cylinder in the tool. This cylinder causes an extendible piston to be displaced toward a cutting or crimping head.
Implementation Method 2
The spacer is positioned between the burst disc and the lock nut and is configured to transfer the supporting force applied by the lock nut to the burst disc.
Data Source
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AI summary
Embodiments of the invention provide a ram assembly for a hydraulic tool. The ram assembly includes a ram piston having a ram cavity. The ram piston receives a hydraulic pressure reaction force. The ram assembly further includes an overload assembly disposed in the ram cavity or in a cavity defined by a manifold. The overload assembly includes a burst disc positioned at a first end of the ram cavity or manifold, a lock nut positioned at a second end of the ram cavity or manifold, and a spacer positioned between the burst disc and the lock nut. The spacer transfers a supporting force applied to the lock nut to the burst disc. The hydraulic pressure reaction force and the supporting force both act in the same direction, and thus, are additive forces acting on the burst disk.