Modular Power Handle with Interlock and Secondary Switch
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Solution Overview
Problem
Existing multi-purpose power hand tools lack safety and functional features that allow a universal power handle module to effectively power and control both saws and reversible power tools, with prior devices often requiring cumbersome simultaneous actuation of safety and trigger switches, and lacking appropriate control modes for different operational requirements.
Innovation Solution
A modular electric tool system with a power handle module featuring a trigger switch, interlock operator, secondary switch, and electrical connectors that allow for safe operation and mode selection, including direction control for reversible tools and speed modulation, integrated within a housing with rechargeable battery cells and complementary connectors for secure attachment to special-purpose tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a universal power handle module is used to power multiple special-purpose tools, then cost is reduced and versatility is improved, but safety control and functional adaptability deteriorate due to lack of tool-specific control features
Solution Approach 1:
The interlock operator is designed to dynamically change its state based on the attached tool type. It can be positioned in different locations along its travel path, with each position enabling specific control features (safety switch for saws, direction switch for reversible tools, speed modulation for fastener drivers). This dynamic reconfiguration allows the universal power handle module to adapt its control characteristics to match the specific safety and functional requirements of each attached special-purpose tool.
2Reliability
If a button-type safety switch mounted on the handle side is used, then safety interlocking is achieved, but ease of operation deteriorates due to requirement for simultaneous thumb and finger actuation
Solution Approach 1:
The safety control function is segmented from the trigger mechanism. Instead of requiring simultaneous actuation of a button and trigger, the interlock operator is divided into distinct functional zones along its travel path. The first position provides safety interlocking by blocking trigger movement, while subsequent positions provide tool-specific control features. This segmentation allows the safety function to be performed by the interlock operator's position rather than requiring coordinated multi-point actuation.
3Ease of operation
If simple sliding couplings are used for battery pack attachment, then ease of installation and removal is improved, but reliability and electrical connection stability deteriorate
Solution Approach 1:
The electrical connection system merges multiple functions into a single integrated connector assembly. The connector simultaneously provides mechanical attachment (replacing simple sliding couplings), electrical connectivity for power and control signals, and tool identification capabilities. This unified approach maintains the ease of attachment and removal while significantly improving reliability through positive mechanical engagement and stable electrical contacts for all signal paths.
Data Source
AI summary
A power handle module encloses rechargeable batteries which can be used to power a number of modular special-purpose tools which may be mounted to the power handle module. The power handle module includes a hand grip, a trigger switch operated by a trigger and a first connector for engagement with a second connector on the special-purpose tool. An interlock operator on the handle module may be moved between a guard position where it resists pressure to move the trigger and at least one armed position, in which position it allows the trigger to be pressed. A secondary switch is mounted within the power handle module. When the special-purpose tool is a fastener driver the secondary switch controls direction of rotation of the motor on the tool. The fastener-driving tool includes a link for mechanically joining the secondary switch and the interlock operator upon connection of the first and second connectors such that by moving the interlock operator between the first and second armed positions the secondary switch is moved between switch positions. When the special-purpose tool is a saw the secondary switch provides a safety interlock switch preventing inadvertent rotation of the motor on the tool. The saw tool includes an engagement face that engages the secondary switch upon connection of the first and second connectors to move the secondary switch to one of the switch positions and resilient means for biasing the interlock operator to the guard position.