Impact Tool Camshaft Hammer Mechanism High Torque
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Solution Overview
Problem
High torque impact wrenches face challenges in delivering sufficient fastening torque while maintaining low current draw, and existing designs often compromise on torque output or durability to achieve this.
Innovation Solution
The impact tool features a drive assembly with a camshaft-driven hammer mechanism that converts continuous torque into consecutive rotational impacts, capable of producing at least 1,700 ft-lbs of fastening torque without exceeding 100 Amperes of current, utilizing a battery-powered motor and optimized camshaft designs for increased hammer travel and energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high torque output is achieved through conventional motor and drive designs, then fastening torque capability is improved, but current draw increases beyond acceptable limits
Solution Approach 1:
The impact mechanism converts continuous motor rotation into periodic impact events through the camshaft and hammer assembly. The hammer strikes the anvil at specific intervals during camshaft rotation, creating discrete torque pulses rather than continuous torque application. This periodic action allows the motor to operate at lower average current levels while delivering high peak torque during impact events, resolving the contradiction between torque output and current draw.
Solution Approach 2:
The patent replaces a conventional direct-drive mechanical torque transmission system with an impact-based mechanical system. Instead of using a large motor to directly produce continuous high torque, the system uses a smaller motor to drive a camshaft that converts rotational motion into reciprocating hammer motion, which then delivers impulsive torque to the anvil. This substitution allows lower current draw while achieving equivalent or superior torque delivery through the impact mechanism.
2Force
If hammer travel distance is increased to improve impact energy, then fastening torque capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent optimizes the camshaft geometry parameters, specifically the cam profile shape, rise distance, and follower engagement angles, to achieve the desired hammer travel distance and impact characteristics. By carefully selecting and adjusting these geometric parameters, the design achieves long hammer travel for high impact energy while maintaining manufacturability through standardized camshaft fabrication processes and off-the-shelf follower components.
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 solution effectively delivers high fastening torque with controlled current draw, enhancing the tool's efficiency and durability by optimizing the camshaft design and energy storage mechanisms.
Implementation Method 1
a motor supported within the motor housing portion
Implementation Method 2
a camshaft driven by the motor for rotation about an axis, and a hammer configured to reciprocate along a travel portion of the camshaft
Implementation Method 3
a hammer configured to reciprocate along a travel portion of the camshaft between a rearmost position and a forwardmost position to deliver rotational impacts to the anvil
Data Source
AI summary
An impact tool includes a housing including a front housing coupled to a motor housing portion, a motor supported within the motor housing portion, a battery pack supported by the housing for providing power to the motor, the battery pack having a nominal capacity of five Amp-hours and a nominal output voltage of at least 18-Volts, and a drive assembly supported within the housing and configured to convert continuous torque from the motor to consecutive rotational impacts upon a workpiece capable of developing at least 1,700 ft-lbs of fastening torque. The drive assembly includes a camshaft driven by the motor for rotation about an axis, an anvil extending from the front housing, and a hammer configured to reciprocate along a travel portion of the camshaft between a rearmost position and a forwardmost position to deliver rotational impacts to the anvil in response to rotation of the camshaft.