Internal Dampening System for Percussion Rock Drill Piston-Hammer
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Solution Overview
Problem
Existing pressure fluid actuated reciprocating piston-hammer percussion rock drills experience excessive impact when the shank is moved forward, leading to unnecessary wear of components due to the continuous high-pressure fluid driving the piston-hammer, which prior methods like shock absorbers and cushions cannot effectively mitigate without wearing out.
Innovation Solution
An internal dampening system is implemented, featuring a trip section with a center area of lesser diameter than the shoulders, which mechanically aligns with specific ports to reduce fluid flow and slow the piston-hammer's movement when the shank is forward of its power position, using a combination of port alignment and a dash pot to control fluid flow and pressure differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the sliding sleeve type valve continuously drives the piston-hammer with high pressure fluid when the shank is forward, then the piston-hammer maintains operational speed, but excessive impact force is generated causing component wear
Solution Approach 1:
The valve system dynamically adjusts fluid flow based on shank position. When the shank moves forward out of the power position, the valve automatically reduces or stops high pressure fluid flow to the piston-hammer, preventing excessive impact while maintaining operational speed during normal drilling. This dynamic control eliminates the need for mechanical shock absorbers.
Solution Approach 2:
The system uses the shank's position as feedback to control valve operation. The valve responds to the forward movement of the shank by modulating fluid flow, creating a closed-loop control system that automatically prevents excessive impact forces without requiring external sensing devices or complex control mechanisms.
2Object-affected harmful factors
If shock absorbers or cushions are used to absorb piston-hammer energy when the shank is forward, then impact force is reduced, but the shock absorbers wear themselves and require replacement
Solution Approach 1:
The valve system serves itself by using the existing operational parameters (shank position, fluid pressure) to automatically control its own operation. The valve reduces fluid flow in response to shank position without requiring separate control systems, sensors, or maintenance-prone components like shock absorbers and cushions.
Solution Approach 2:
The patent replaces mechanical shock absorption systems (shock absorbers, cushions, springs) with a fluid control system. Instead of mechanically absorbing impact energy, the system uses hydraulic or pneumatic fluid flow control to prevent excessive impact forces in the first place, eliminating wear-prone mechanical components.
3Adaptability or versatility
If the shank is moved forward out of the power position, then drilling operation can be paused, but the piston-hammer continues to gain speed over a longer distance causing excessive impact
Solution Approach 1:
The valve system takes preliminary action by detecting the shank's forward movement and preemptively reducing fluid flow to the piston-hammer before excessive speed accumulation can occur. This prevents the condition from developing rather than reacting to it after the fact.
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 internal dampening system effectively reduces the frequency and force of the piston-hammer's impact when the shank is forward, minimizing wear on components and extending the life of the drill by reducing excessive impact, without the need for wear-prone shock absorbers or cushions.
Implementation Method 1
mechanically aligns with specific ports to reduce fluid flow and slow the piston-hammer's movement
Implementation Method 2
using a combination of port alignment and a dash pot to control fluid flow and pressure differentials
Data Source
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AI summary
A percussion drill, and methods of using the same, including a shank in mechanical alignment with a piston- hammer and a valve in fluid communication with the piston- hammer. The percussion drill further includes an internal hydraulic dampening system for reducing the velocity of the piston-hammer when the shank is forward of a power position relative to the velocity of the piston-hammer when the shank is in a power position. Preferably, the internal hydraulic dampening system includes mechanical alignment of a portion of the piston-hammer with a port in fluid communication with the valve, operable to reduce fluid flow into an area surrounding the valve when the piston-hammer is forward of its position relative to its normal operation.