Impact Mechanism Cam Ring for High Torque With Shorter Hammer Travel
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Solution Overview
Problem
Existing impact power tools face challenges in efficiently transitioning between rotary and impact modes, particularly in achieving high torque output with minimal components and maximizing the mechanical components, and they often require complex designs that do not optimize the use of a stiffer spring to facilitate the efficient operation of the tool.
Innovation Solution
The impact power tools include a cam shaft with angled or curved grooves and a cam ring that are nested between the cam shaft and the hammer shaft and the hammer, which allows for a stiffer spring to be used while achieving the same or greater torque output with less axial travel of the hammer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a stiffer spring is used to facilitate efficient operation, then the spring can provide greater force, but the axial travel of the hammer increases
Solution Approach 1:
The cam ring is nested between the cam shaft and the hammer, creating a multi-layer mechanical system where the cam ring's rotational movement is converted to axial movement of the hammer through its cam groove geometry. This nested arrangement allows the stiffer spring to operate within a compact axial space while still providing sufficient force.
Solution Approach 2:
The cam ring converts rotational motion (angular dimension) into axial linear motion through its cam groove profile. By introducing this dimensional transformation, the system can achieve greater spring force with reduced axial travel distance, as the hammer's axial displacement is controlled by the cam geometry rather than单纯 spring expansion.
2Length of moving object
If the hammer axial travel is reduced, then the tool becomes more compact, but the torque output may be compromised
Solution Approach 1:
The cam ring introduces rotational motion to compensate for reduced axial travel. The hammer experiences greater rotational travel relative to the cam shaft while maintaining minimal axial displacement, allowing the system to generate sufficient torque through the rotational impact mechanism rather than relying solely on axial movement.
Solution Approach 2:
The system dynamically adjusts the hammer's motion characteristics through the cam ring's rotational movement. The hammer can rotate at different angles relative to the cam shaft during the impact cycle, optimizing the torque transmission while maintaining compact axial dimensions. This dynamic rotational capability allows high torque output without requiring large axial travel.
3Force
If a cam ring is added between the cam shaft and hammer, then the design becomes more complex, but the torque output and rotational travel are enhanced
Solution Approach 1:
The cam ring serves multiple functions simultaneously: it acts as a structural support element, a motion conversion mechanism (transforming rotational to axial movement), and a torque multiplication device. By consolidating these functions into a single component with cam grooves, the design achieves enhanced torque output without proportionally increasing complexity.
Solution Approach 2:
The cam ring is nested within the existing space between the cam shaft and hammer, utilizing available volume rather than adding external components. This nested configuration allows the cam ring to provide additional functional capability while maintaining a compact overall structure, minimizing the increase in device complexity.
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 design enables a stiffer spring to be used while achieving the same or greater torque output with less axial travel of the hammer, and the addition of a cam ring that is nested between the cam shaft and the hammer enables greater rotational travel of the hammer relative to the cam shaft in the same or smaller axial distance, thus enhancing the tool's performance.
Implementation Method 1
A spring is configured to bias the hammer toward the anvil
Implementation Method 2
the cam shaft defining a first angled or curved (e.g., V-shaped, U-shaped, parabolic) cam groove on an outer surface of the cam shaft
Implementation Method 3
A first ball is received in the first cam groove and the second cam groove and configured to couple the cam ring to the cam shaft for rotational and axial movement relative to the cam shaft
Implementation Method 4
the hammer projection rotationally strikes the anvil projection to impart a rotational impact to the anvil
Data Source
AI summary
A rotary impact tool includes a motor and an impact mechanism. The impact mechanism includes a cam shaft with a first cam groove rotatably driven by the motor, a cam ring received over the cam shaft with a second cam groove on its inner surface and a third cam groove on its outer surface, a hammer received over the cam ring with a fourth cam groove on its inner surface, an anvil with an output shaft and configured to be selectively engaged by the hammer, a spring configured to bias the hammer toward the anvil, a first ball received in the first and second cam grooves to couple the cam ring to the cam shaft, and a second ball received in the third and fourth cam grooves to couple the hammer to the cam ring.