Motorized Screwdriver Torque Limiter Freewheel
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Solution Overview
Problem
Conventional screwdrivers are tiring and time-consuming for multiple screw connections, while electric screwdrivers lack sufficient sensitivity, particularly for small screws, and can unintentionally shear them off due to inadequate torque control.
Innovation Solution
A screwdriver with a motor-driven mechanism that includes a torque limiter and freewheel, allowing for precise control of torque, enabling quick and fatigue-free operation by automatically applying a set maximum torque and decoupling from manual input once reached, ensuring sensitive handling of screws without shearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an electrically operated screwdriver with torque limiter is used, then tightening speed and productivity are improved, but torque control sensitivity deteriorates leading to potential screw shearing
Solution Approach 1:
The screwdriver dynamically switches between motor-driven mode for rapid initial tightening and manual mode for sensitive final adjustment. The system transitions from automated high-speed operation to manual precision control, allowing the user to apply delicate torque adjustments once the motor reaches the desired torque level, thus preventing screw shearing while maintaining high productivity.
Solution Approach 2:
The motor serves as an intermediary that provides controlled torque up to a predetermined level, then hands off control to the user for fine-tuning. This intermediary mechanism delivers the benefits of electric power for speed while preserving human sensitivity for the critical final adjustment phase.
2Measurement precision
If manual torque application is used, then torque control sensitivity is improved, but productivity and user fatigue deteriorate
Solution Approach 1:
The motor performs the preliminary action of tightening the screw to the desired torque level automatically and quickly, eliminating the need for users to manually apply torque for the entire tightening process. This preliminary automated action preserves user energy and time while maintaining precision control capability for any necessary final adjustments.
3Productivity
If continuous motor drive is used, then productivity is improved, but risk of screw shearing increases due to excessive torque
Solution Approach 1:
The torque limiter provides feedback control by monitoring the torque applied to the screw and automatically stopping the motor when the predetermined torque level is reached. This feedback mechanism prevents the motor from applying excessive torque that could shear the screw, ensuring reliable operation while maintaining high productivity through automated control.
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
Enables quick and fatigue-free tightening and loosening of screws with precise torque control, preventing shearing of small screws by automatically limiting torque and allowing sensitive manual adjustments beyond the set limit.
Implementation Method 1
The drive mechanism includes a motor which can generally be driven electrically
Implementation Method 2
The freewheel is designed here to decouple the motor from the bit holder or the screwdriver blade whenever manual torque is applied
Implementation Method 3
the drive mechanism includes a torque limiter by which the output torque that is acting on the screw to be tightened or loosened can be limited to a desired value that is less than the shearing torque of the screw
Data Source
AI summary
A screwdriver includes a handle having a longitudinal axis. At the one end of the handle, the screwdriver includes a bit holder extending in the direction of the longitudinal axis or a screwdriver blade extending in the direction of the longitudinal axis. The screwdriver is further includes a drive mechanism in the handle. The drive mechanism causes a bit holder in the handle or the screwdriver blade opposite the handle to rotate. The drive mechanism includes a motor and a freewheel through which the motor can be coupled to the bit holder or the screwdriver blade. The freewheel is designed to relieve the torque when manual torque is introduced into the bit holder or the screwdriver blade through the handle. The drive mechanism further includes a torque limiter for limiting the drive torque of the motor on the bit holder or the blade.