Power Tool Drive Head With Torque-Switched Bidirectional Stopping
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Solution Overview
Problem
Existing open end power tools can only rotate nuts in one direction and require mechanical stops or sensors for bidirectional rotation, which increase complexity and cost.
Innovation Solution
An arrangement for a power tool with a stopping device that includes a movable element and a limiting element, allowing dual-direction rotation without sensors by switching between states with defined torques, enabling both tightening and loosening without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical stop is used to position the driven member in the open position, then the driven member can be positioned accurately, but the driven member can only rotate the nut in one direction
Solution Approach 1:
The stopping device uses a movable element that can dynamically switch between two stable positions (first region and second region) depending on the rotation direction. This dynamic positioning allows the device to adapt its stopping behavior based on operational needs, enabling bidirectional rotation while maintaining accurate positioning through the two distinct stable states of the movable element
2Ease of operation
If a sensor is used to detect the open position, then bidirectional rotation is enabled, but costs and complexity increase due to additional cabling and components
Solution Approach 1:
The stopping device is self-regulating through its movable element that automatically positions itself in the appropriate region based on the rotation direction and torque applied. The device uses its own mechanical structure and torque characteristics to detect and respond to operational states, eliminating the need for external sensors, controllers, and cabling systems
Solution Approach 2:
The patent replaces electronic sensing systems with a purely mechanical stopping mechanism. The movable element's physical interaction with the limiting element creates torque-based positioning that substitutes for electronic detection, using mechanical forces and geometries to achieve what would otherwise require sensors and control electronics
3Adaptability or versatility
If a sensor and control circuit are used for bidirectional rotation, then the neutral position can be assumed, but the design becomes more complicated
Solution Approach 1:
The stopping device automatically assumes the neutral position through the natural behavior of its movable element, which settles into stable positions based on torque application. The device self-regulates without requiring external control circuits to detect position or command directional changes
Solution Approach 2:
The stopping device serves multiple functions simultaneously: it provides mechanical stopping in both rotation directions, defines the neutral position, and enables bidirectional operation through its single integrated structure. The movable element performs multiple roles including position detection, torque transmission, and directional control without requiring separate components for each function
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3b
AI summary
An arrangement (36) for a power tool (10), the arrangement comprising a base structure (54); a drive member (52) rotatable from a neutral position (82); a stopping device (66) comprising a movable element (68; 112; 140) and a limiting element (70; 106; 114; 128; 138); wherein the stopping device is arranged to adopt a first state (86) where the stopping device allows rotation of the drive member in a first direction (88) and generates a first counter torque (96); wherein the stopping device is arranged to adopt a second state (100) where the stopping device allows rotation of the drive member in a second direction (92) and provides a second counter torque (102); and wherein the stopping device is deflectable to switch from the first state to the second state by rotating the drive member in the second direction from the neutral position with a second switching torque (98) overcoming the first counter torque.