Dual-Actuator Switching Mechanism for Power Tools
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Solution Overview
Problem
Existing power tool switching apparatus require two separate electrical switches and often include complex gear arrangements, increasing construction complexity and cost.
Innovation Solution
A switching apparatus with an actuation assembly comprising two operator-actuable actuation members, where at least one member has an arm with a switch actuator bearing surface that moves between configurations to contact and depress the switch actuator, eliminating the need for separate switches and gear arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate electrical switches are used, then the switching function is achieved, but the device complexity increases
Solution Approach 1:
The patent merges two separate electrical switches into a single switch mechanism. The actuation assembly includes first and second actuation members that both actuate the same single switch, eliminating the need for two separate switches while maintaining the safety function of requiring two-handed operation.
Solution Approach 2:
The single switch is designed to be actuated by multiple different actuation members (first and second actuation members), making it a universal switching element that serves multiple control functions. This multi-functional approach reduces component count while maintaining safety requirements.
2Ease of operation
If a gear arrangement is used, then the actuation mechanism is achieved, but the manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the gear arrangement from the actuation mechanism. Instead of using gears to transmit motion, the design directly couples the actuation members to the switch actuator through arms and bearing surfaces, removing unnecessary intermediate components and reducing manufacturing complexity.
Solution Approach 2:
The patent replaces the complex mechanical gear system with a simpler direct mechanical linkage system. The arms with bearing surfaces provide direct contact and motion transfer to the switch actuator, eliminating the need for gear teeth, gear housings, and associated lubrication and alignment requirements.
Data Source
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AI summary
The present invention relates to power tools and switching apparatus therefor. In particular, it relates to switching apparatus for apparatus, such as power tools, particularly hedgecutters, which require two actuators to be gripped, one by each hand, usually for safety reasons, in order to provide power to the prime mover of the apparatus, such as an electric motor. We describe an apparatus for activating an electrical switch (30) for energising an electric motor. The switch has a switch actuator (30a, 30b) actuatable in an actuation direction by means of an actuation assembly. The actuation assembly comprises first and second operator-actuatable actuation members (11, 12, 33, 35, 44, 45) and is characterised in that the first and second actuation members (11, 12, 33, 35, 44, 45) each comprises a respective arm (20, 21, 42, 50), at least one of which arms (20, 21, 42, 50) includes a switch actuator bearing surface (27). The arms (20, 21, 42, 50) of the first and second actuation members are arranged such that the first and second actuator members (11, 12, 33, 35, 44, 45) are movable between a first configuration in which the switch actuator bearing surface (27) is spaced from the switch actuator (30a, 30b) in the actuation direction and in a direction orthogonal to the actuation direction; and a second configuration in which the switch actuator bearing surface contacts and depresses the switch actuator (30a, 30b). In moving between the first and second configurations, that arm on which the switch actuator bearing surface (27) is formed is adapted to move in a linear motion to align the bearing surface with the switch actuator and the other arm is adapted to move in an arcuate motion to draw the switch actuator bearing surface into operative engagement with the switch actuator (30a, 30b).