Dual-Speed Screwing Device With Acceleration-Controlled Gear Changes
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Solution Overview
Problem
Existing high-torque screwdrivers face inefficiencies due to low rotation frequency resulting from multiple epicyclic gear trains, leading to prolonged screwing times, and current solutions lack versatility in adjusting gear change thresholds based on pre-tightening torque values.
Innovation Solution
A two-speed screwing/unscrewing device with an additional gear train that can be engaged/disengaged via motor acceleration/deceleration control, independent of tightening torque, allowing seamless speed transitions through a selection member and one-way clutches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If multiple epicyclic gear trains are used to achieve high tightening torque, then the tightening torque is improved, but the rotation frequency of the output shaft becomes low, resulting in long screwing time
Solution Approach 1:
The patent implements a dynamic transmission system with an additional gear train that can be automatically engaged or disengaged based on the tightening torque threshold. During pre-tightening, the additional gear train is disengaged to maintain high rotation frequency. When the target torque is reached, the gear train automatically engages to provide high reduction ratio for final tightening, thus dynamically adapting the transmission ratio to different operational phases.
Solution Approach 2:
The transmission system is segmented into a permanent gear train and an additional engageable gear train. The permanent gear train provides base reduction ratio, while the additional gear train provides extra reduction when needed. This segmentation allows the system to switch between different reduction ratios depending on the screwing phase, optimizing both speed and torque characteristics.
2Force
If an additional gear train is added to provide high reduction ratio for high torque, then the tightening torque is improved, but the device complexity increases
Solution Approach 1:
The system employs automatic gear train engagement/disengagement based on torque threshold detection. The control unit monitors the tightening torque and automatically activates the additional gear train when the threshold is reached, eliminating the need for manual intervention or complex control mechanisms. This self-service approach simplifies the overall control system while maintaining high torque capability.
3Device complexity
If the gear change threshold is fixed based on elastic element sizing, then the automatic gear activation is simplified, but the adaptability to different pre-tightening torque values is lost
Solution Approach 1:
The patent enables configurable gear change thresholds by allowing adjustment of the torque detection parameter in the control unit. Instead of being fixed by elastic element physics, the threshold can be electronically adjusted to match different pre-tightening requirements. This parameter change capability provides versatility for different screwing operations while maintaining the simplicity of automatic activation through torque monitoring.
Data Source
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AI summary
The present invention relates to a screwing device comprising: - a housing; - a motor equipped with a rotor; - an output member capable of rotating a drive element of a screwing element; - a transmission connecting said rotor to said output member, said transmission comprising at least one additional gear train capable of being engaged/disengaged; - means for controlling said motor;said device comprising means for engaging said additional gear train, said engagement means being able to take at least: - an engagement state in which said additional gear train is engaged, and - a disengagement state in which said additional gear train is not engaged, the reduction ratio of said transmission between said rotor and said output member being different depending on whether said additional gear train is engaged or not, said reduction ratio being higher when said additional gear train is engaged, where said control means of said motor are configured to generate a predetermined acceleration or deceleration of said rotor, said predetermined acceleration or deceleration acting on said engagement means to make them pass from one of their states to the other.