Hammer Drill Air Spring Adaptation via Selective Bleed Holes
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Solution Overview
Problem
Existing hammer drills lack the ability to adjust their performance characteristics based on the hardness of the material being cut, leading to suboptimal performance in varying conditions.
Innovation Solution
The design incorporates a method to selectively open air entry points, such as bleed holes, depending on the average position of the cutting tool within the tool holder, which adjusts the air spring's strength and the ram's movement, allowing for optimized performance across different material hardnesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single bleed hole configuration is used in the cylinder, then the structure is simple and easy to manufacture, but the performance characteristics cannot be adjusted for different material hardnesses
Solution Approach 1:
The single bleed hole is segmented into multiple bleed holes positioned at different axial locations along the cylinder. Each bleed hole can be selectively opened or closed to adjust the air spring characteristics. This segmentation allows the system to adapt to different material hardnesses while maintaining a relatively simple overall structure.
Solution Approach 2:
The bleed holes are equipped with movable plugs or valves that can dynamically open or close based on the material being cut. This dynamic configuration allows the hammer drill to adjust its performance characteristics in real-time, transforming from a static single-configuration system to a dynamic multi-configuration system.
2Adaptability or versatility
If the air spring strength is fixed, then the device is simpler to operate, but the performance cannot be optimized for different material hardnesses
Solution Approach 1:
The system incorporates sensors that automatically detect the material hardness and selectively open or close the appropriate bleed holes without user intervention. This self-service mechanism maintains ease of operation while enabling performance optimization, as the adjustment process is automated and requires no manual configuration by the user.
Solution Approach 2:
The system uses feedback from sensors monitoring the cutting conditions to automatically adjust the bleed hole configuration. The sensor data provides information about material hardness, and this feedback loop enables the system to self-adjust the air spring strength to optimal values for the current working conditions.
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 adjustment enables improved performance characteristics, including enhanced energy delivery and efficiency, by tailoring the hammer drill's operation to the specific hardness of the material being worked on, as demonstrated by the graphs showing performance variations with different bleed hole configurations.
Implementation Method 1
a piston which is reciprocatingly driven by a motor via a hammer mechanism. The piston in turn reciprocatingly drives a ram which imparts impacts onto a cutting tool via a beat piece
Implementation Method 2
US1402727 discloses a hammer drill where a piston reciprocatingly drives a ram within a cylinder via an air spring
Data Source
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AI summary
A hammer drill comprising: a body (2); a cylinder (58) mounted within the body (2); a piston (60) slideably mounted within the cylinder (58); a motor (24) mounted within the body (2) having an output spindle (30); a reciprocating drive mechanism mounted within the body which, when the motor is activated, converts the rotary movement of the spindle (30) of the motor (24) into a reciprocating movement of the piston (60) within the cylinder (58); a ram (64) slideably mounted within the cylinder (58) which is reciprocatingly driven by the reciprocating movement of the piston (60) via an air spring (62); at least two air entry points (200, 202) formed through the wall of the cylinder (58) in different axial positions along the length of the cylinder (58), each of which are capable of replenishing the air spring (62); a tool holder (14) mounted on the body, the tool holder being capable of holding a cutting tool (22) which, during normal use, is repetitively struck by the reciprocating ram (64); wherein there is further provided a selector mechanism (204) which selectively opens and close the air entry points (200, 204); characterized in that the selector mechanism opens only one air entry point (200, 202) at any one time during normal use, the selector mechanism closing all other air entry points (200, 202), each of the air entry point (200, 202) capable of replenishing the air spring (62) during normal use when opened by the selector mechanism (204).