Power Screwdriver Rotary Joint Automatic Locking Mechanism
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Solution Overview
Problem
Power screwdrivers with rotary joints face safety hazards due to uncontrolled rotation about their axis when the drive part is not properly locked, leading to potential operator risks during screwing operations.
Innovation Solution
A power screwdriver design featuring a rotary joint with a coaxially arranged actuating ring that automatically locks into a blocking position using a spring element, ensuring the drive part remains rotatable for comfortable positioning but securely blocks torque during screwing, preventing uncontrolled rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the drive part is made rotatable relative to the gear case via a rotary joint, then the operator can achieve a more comfortable operating position, but the drive part may rotate uncontrollably about its axis during screwing operations creating safety hazards
Solution Approach 1:
The rotary joint incorporates a dynamic locking mechanism that transitions between locked and unlocked states based on operational phase. During positioning, the joint is unlocked allowing rotation; during screwing, the joint locks to prevent uncontrolled rotation. This dynamic state change resolves the contradiction between needing rotation for comfort and needing stability for safety.
Solution Approach 2:
The locking mechanism automatically engages and disengages based on the operational state without requiring manual intervention. The spring element and locking elements work together to self-lock the rotary joint when torque is applied during screwing operations, and self-unlock when the trigger is actuated for positioning, ensuring safety while maintaining ease of operation.
2Reliability
If a locking mechanism is added to prevent uncontrolled rotation, then operating safety is improved, but the device complexity increases
Solution Approach 1:
The locking mechanism is merged with the rotary joint structure itself, using the existing rings and torque transmission paths. The locking elements are integrated into the drive-associated ring and gearing-associated ring, eliminating the need for separate locking components and reducing overall device complexity while maintaining safety.
Solution Approach 2:
Spring elements are introduced as intermediaries to mediate between the locking elements and the torque transmission path. These springs provide the necessary force to engage and disengage the locking elements smoothly, simplifying the control mechanism while ensuring reliable locking without adding complex actuation systems.
3Reliability
If the rotary joint is locked in the blocking position, then uncontrolled rotation is prevented, but the drive part cannot be rotated into a comfortable operating position
Solution Approach 1:
The rotary joint operates in periodic cycles: unlocked state for positioning, locked state for screwing, unlocked state for repositioning, and so on. This periodic transition between locked and unlocked states allows the system to alternately achieve positioning flexibility and operational safety as needed during different phases of use.
Solution Approach 2:
The locking mechanism dynamically responds to operational conditions, transitioning from locked to unlocked state when the trigger is actuated for positioning, and back to locked state when screwing begins. This dynamic adaptability ensures that the rotary joint is flexible when needed for positioning and rigid when needed for safety during screwing operations.
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
Ensures high operating safety by automatically locking the rotary joint in the blocking position, preventing unintended torque transmission to the handle and ensuring a secure screwing operation without operator risk, even with higher torque applications.
Implementation Method 1
a spring element which acts upon the actuating ring along its movement path, extending from the blocking position to the release position, in the direction of the blocking position
Data Source
AI summary
A power screwdriver is provided with a drive part having a drive motor, a gear case with gearing elements; an output shaft led out of the gear case; a support offset laterally relative to the output shaft and fixedly connected to the gear case, and a rotary joint with drive-associated ring connected to the drive part and gearing-associated ring connected to the gear case. An actuating ring is arranged coaxially to the output shaft and is movable relative to the drive-associated ring and relative to the gearing-associated ring. It is movable between a release position, in which the rings are rotatable relative to each other, and a blocking position, in which the rings are blocked relative to each other. A spring element acts on the actuating ring over its movement path, extending from blocking position to release position, in the direction of the blocking position.