Linerbolt Removal Tool Piston Cap Separation for Dry-Fire Shock
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Solution Overview
Problem
Conventional linerbolt removal tools face issues with shock loading during 'dry-fire' scenarios, piston cap failure due to stress differences, and inefficient sealing, leading to reduced tool lifespan and performance.
Innovation Solution
The design includes a piston cap that separates from the piston during the firing stroke, with a front portion impacting an internal surface to isolate the piston from the accumulator, and a ledge for rebound strokes, reducing stress ranges and incorporating a seal between the piston and piston cap to maintain pressure isolation, along with cross pins mounted in resilient bushes to absorb shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid piston cap design is used to withstand firing stresses, then the piston cap can handle the impact force, but it experiences excessive stress during rebound strokes leading to fatigue failure
Solution Approach 1:
The piston cap is designed to be movable relative to the piston, transitioning from a fixed rigid connection to a dynamic system where the cap can separate during firing and rebound strokes. This allows the system to adapt its configuration based on the operational phase, reducing stress concentrations that lead to fatigue failure while maintaining sufficient strength during impact.
Solution Approach 2:
The piston assembly is segmented into separate components: the piston body and the piston cap. This segmentation allows independent movement and stress distribution, where the cap can separate from the piston during extreme conditions, preventing stress propagation throughout the entire piston cap structure and reducing fatigue accumulation.
2Power
If the piston cap remains attached to the piston during firing, then the force is efficiently transmitted to the moil, but shock loading occurs during dry-fire scenarios reducing tool lifespan
Solution Approach 1:
The connection between piston and piston cap changes dynamically based on operational conditions. During normal firing, the cap remains attached for efficient force transmission. During dry-fire scenarios, the cap automatically separates, absorbing the shock loading and preventing damage to the tool, thus extending lifespan while maintaining power transmission capability when needed.
Solution Approach 2:
The movable piston cap design provides beforehand cushioning by allowing separation before extreme shock loads can damage the tool. This preventive mechanism absorbs potential shock loading during dry-fire scenarios before it can propagate through the tool structure, protecting critical components and extending tool lifespan.
3Ease of operation
If cross pins are rigidly mounted to stop moil movement, then the moil is constrained effectively, but high shock waves are generated compromising tool components
Solution Approach 1:
The cross pins are mounted in resilient bushes that act as flexible elements, allowing the pins to constrain moil movement while absorbing shock waves through elastic deformation. This flexible mounting system maintains operational control of the moil while preventing the transmission of harmful shock waves to other tool components.
Solution Approach 2:
The resilient bushes serve as intermediary elements between the cross pins and the tool housing. These mediators allow the cross pins to perform their constraining function while isolating the shock waves generated during operation, preventing damage to tool components through the buffering effect of the resilient material.
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 design reduces stress on the piston cap, enhances its durability, and minimizes recoil, leading to improved performance and extended tool lifespan by evenly distributing impact loads and reducing shock loading.
Implementation Method 1
causing pressurised gas within the accumulator to accelerate the piston in a forward direction toward the moil
Implementation Method 2
cross pins mounted in resilient bushes to absorb shock
Data Source
AI summary
A linerbolt removal tool, including: a housing; a moil supported for reciprocating movement by the housing; an inertial body located within the housing; a gas charged accumulator extending from the inertial body away from the moil; a piston moveable within the inertial body between a striking position at which the piston strikes the moil and a retracted position, whereby firing the piston from its retracted position to its striking position includes causing pressurised gas within the accumulator to accelerate the piston toward the moil, wherein the piston has a striking end for striking the moil and an opposing rear end; and a piston cap that encloses the rear end of the piston, wherein during firing, the piston and the piston cap initially accelerate together and prior to the piston reaching its striking position the piston cap separates from the piston, whereby the piston cap isolates the piston from the accumulator.