Dual-Hammer Impact Ratchet Tool with Camshaft and Pawl
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Solution Overview
Problem
Existing impacting ratchet tools lack efficiency in delivering rotational impacts and direct driving modes, often resulting in reduced torque and increased vibrations.
Innovation Solution
The impact tool incorporates a dual-hammer mechanism with a camshaft-driven anvil and a crankshaft coupled to a yoke, allowing for rotational impacts in one direction and direct driving in the opposite direction, while a pawl mechanism enables selective locking and ratcheting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single hammer mechanism is used for impacting, then the device complexity is reduced, but the productivity and torque delivery are insufficient
Solution Approach 1:
The impacting mechanism is segmented into multiple hammers (first hammer and second hammer) that operate independently on different sides of the anvil. This segmentation allows simultaneous or sequential impacting actions, increasing torque delivery and productivity while maintaining manageable device complexity through modular arrangement
Solution Approach 2:
Multiple hammer mechanisms are merged into a single integrated impacting system sharing common components (camshaft, anvil, housing). This combining approach achieves enhanced productivity through coordinated multi-hammer action while controlling device complexity by reusing structural elements across the hammer assembly
2Adaptability or versatility
If the camshaft rotates in both directions for dual-mode operation, then the adaptability is improved, but the reliability may deteriorate due to increased mechanical stress
Solution Approach 1:
The camshaft is designed with direction-dependent cam profiles that dynamically change the impacting mechanism's behavior based on rotation direction. In first direction, the profile enables rotational impacting; in second direction, it enables direct driving. This dynamic adaptation improves versatility while maintaining reliability by ensuring proper load paths in each mode
Solution Approach 2:
The camshaft profile parameters are specifically designed to change the mechanical behavior based on rotation direction. The cam geometry transforms the same rotational input into different output characteristics (impacting vs. direct driving) by altering force transmission parameters, enabling multi-mode operation without compromising reliability
3Object-generated harmful factors
If the hammer mass is increased to reduce vibrations, then the force of impacting is improved, but the weight of the tool increases
Solution Approach 1:
The total hammer mass is segmented into multiple hammers distributed around the anvil. This segmentation reduces vibrations by distributing impact forces across multiple contact points, and the distributed mass configuration minimizes unbalanced forces that cause tool weight perception and actual vibration, achieving vibration reduction without excessive overall weight increase
Solution Approach 2:
The multiple hammers are positioned and mass-balanced to act as counterweights to each other. The distribution of hammer masses creates balancing effects that reduce net vibrations and unbalanced forces, allowing effective impacting force while controlling overall tool weight and vibration levels
4Productivity
If a dual-hammer mechanism is implemented, then the productivity and torque delivery are enhanced, but the device complexity increases
Solution Approach 1:
The second hammer is positioned within or adjacent to the first hammer's operational space, with both hammers nested within the same housing and sharing common structural support. This nesting arrangement enhances productivity through dual impacting action while controlling device complexity by compact integration and shared components
Solution Approach 2:
The camshaft serves multiple functions: it drives both hammers for impacting, enables direct driving mode, and transitions between operating modes. This multi-functionality enhances productivity through versatile operation while reducing device complexity by eliminating the need for separate mechanisms for each function
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 enhances torque delivery and reduces vibrations by providing increased rotating mass and efficient energy transfer, while maintaining a compact tool size.
Implementation Method 1
a camshaft driven by the motor to rotate about the first axis, an anvil, and a hammer configured to reciprocate along the camshaft to impart rotational impacts to the anvil in response to rotation of the camshaft
Implementation Method 2
a crankshaft coupled to the anvil for co-rotation with the anvil, a yoke driven by the crankshaft to reciprocate about a second axis perpendicular to the first axis in response to rotation of the crankshaft
Implementation Method 3
a pawl configured to selectively couple the output drive to the yoke for co-rotation with the yoke in a first rotational locking direction about the second axis and to permit the yoke to rotate relative to the pawl in a second rotational locking direction
Implementation Method 4
The first hammer is mounted to the camshaft and includes hammer lugs that are configured to rotationally impact the anvil lugs
Data Source
AI summary
An impact tool including a housing, a motor having an output shaft rotatable about a first axis, and an impact mechanism. The impact mechanism includes a camshaft, an anvil, and a hammer configured to reciprocate along the camshaft to impart rotational impacts to the anvil in a first operating mode and to directly drive the anvil in a second operating mode. The impact tool further includes a crankshaft coupled to the anvil for co-rotation with the anvil, a yoke driven by the crankshaft to reciprocate about a second axis perpendicular to the first axis, an output drive, and a pawl configured to selectively couple the output drive to the yoke for co-rotation with the yoke in a first rotational locking direction about the second axis and to permit the yoke to rotate relative to the pawl in a second rotational locking direction about the second axis.