Trigger-Actuated Mechanical Brake for Power Tool Spindle
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Solution Overview
Problem
Portable power tools often lack a reliable and convenient brake mechanism to stop the spindle quickly and securely after operation, posing safety risks and requiring additional manual actions for locking the spindle from rotation.
Innovation Solution
A mechanical brake assembly automatically operated by a trigger, comprising a brake disc, spindle lock with friction material, and a motion transmit mechanism, which quickly stops the spindle when the trigger is released and locks it using a protrusion and spindle locking member for safe operation and tool exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an electrically controlled brake is used to provide braking force to the power tool, then the braking performance is improved, but the cost increases and reliability decreases
Solution Approach 1:
The patent replaces the electrically controlled brake system with a purely mechanical brake assembly. The mechanical brake uses a compression spring to apply braking force to a brake disc attached to the motor spindle, eliminating the need for electrical control components. This substitution improves reliability by removing electrical system vulnerabilities while maintaining effective braking capability through mechanical means.
Solution Approach 2:
The mechanical brake assembly is designed to be automatically activated by the trigger mechanism itself. When the trigger is released, it automatically engages the brake through a cam or lever action that compresses the spring and applies it to the brake disc. This self-service design eliminates the need for separate electrical control systems, reducing cost and improving reliability.
2Reliability
If a mechanical brake with independent operation is used, then the braking function is achieved, but the operation becomes cumbersome requiring additional manual action
Solution Approach 1:
The patent merges the brake operation with the existing trigger mechanism. The trigger serves dual functions: activating the motor during operation and automatically engaging the brake when released. This integration eliminates the need for separate brake activation actions, making the operation convenient while maintaining reliable braking function.
Solution Approach 2:
The brake mechanism is pre-positioned and spring-loaded during normal operation, ready to engage immediately when the trigger is released. The compression spring maintains constant readiness to apply braking force, so no additional manual action is needed at the moment of braking - the system is already prepared to act instantaneously.
3Speed
If conventional power tools with brake are used, then quick stopping is achieved, but the spindle is not locked from rotation for tool exchange
Solution Approach 1:
The brake assembly is designed to perform multiple functions: it provides quick braking when the trigger is released, and it also locks the spindle in position to prevent rotation during tool exchange operations. This multi-functionality is achieved through the mechanical design where the brake components can maintain a locked position on the spindle, combining braking and locking capabilities in a single assembly.
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 provides a simple, reliable, and safe mechanism for quick spindle braking and locking, enhancing operator safety and convenience by integrating braking and locking functions into a single, easy-to-operate mechanism suitable for various power tools.
Implementation Method 1
a spindle lock (5) carrying a friction material (7) and being able to move in a first direction towards and away from the brake disc (12)
Data Source
AI summary
A portable power tool includes a motor housing and a motor mounted in the motor housing. The motor includes a rotary spindle. The portable power tool also includes a trigger configured to be actuated and released to switch on and off the motor. The portable power tool also includes a mechanical brake assembly connected with the trigger and automatically operated by the trigger. Accordingly, the brake assembly releases the spindle when the trigger is activated and brakes the spindle when the trigger is released.