Bayonet Connector Locking Mechanism for Power Tool Attachments
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Solution Overview
Problem
Conventional hand-held power tool attachments with bayonet joints lack secure locking mechanisms, leading to potential damage and user safety issues due to loose connections and ambiguous locking states during operation.
Innovation Solution
A bayonet-type connector system with a flange ring and detent ring, where the fastening ring is rotatably supported and engages with the flange ring through a coupled rotary and axial movement, providing a lockable interface with minimal play and clear indication of the locking state through a detent mechanism and indicating device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bayonet joint is used for fastening the tool attachment, then the connection can be quickly attached and detached, but the joint cannot be locked and may come loose due to vibrations during operation
Solution Approach 1:
The bayonet joint incorporates a locking mechanism that transitions the connection from a static, unsecured state to a dynamically locked state. The locking element can engage with locking surfaces to secure the connection against vibrations, while still allowing quick attachment and detachment when needed.
Solution Approach 2:
The joint design changes the connection parameter from purely rotational engagement to a combination of rotational engagement and axial locking. This dual-mode engagement provides both ease of operation for attachment/detachment and reliable locking during operation.
2Reliability
If a locking mechanism is added to the bayonet joint, then the connection stability is improved, but the device complexity increases
Solution Approach 1:
The locking mechanism is merged with the existing bayonet joint structure rather than being added as a separate, independent system. The locking element, locking surfaces, and indicating device are integrated into the flange ring and fastening ring assembly, providing reliable locking without proportionally increasing overall complexity.
Solution Approach 2:
The locking mechanism is designed to be self-indicating through the indicating device that shows the locking state without requiring additional sensors or complex feedback systems. The mechanism itself provides the indication through its structural configuration.
3Device complexity
If the locking element angular position is not unambiguous, then the locking mechanism is simpler, but the locking state cannot be unequivocally indicated
Solution Approach 1:
The indicating device uses visual differentiation (analogous to color changes in TRIZ) to clearly indicate the locking state. The indicating element changes its visual appearance or position to provide unambiguous feedback to the user about whether the connection is locked, without adding complex sensing or control systems.
4Reliability
If a ball and groove locking mechanism is used, then axial locking is achieved, but a large tilting clearance occurs in the interface
Solution Approach 1:
Instead of using a ball (spherical) locking element that creates point contact and allows tilting, the invention uses a groove-based locking mechanism that provides surface contact. This groove engagement constrains both axial and tilting movements, eliminating large tilting clearances while maintaining axial locking capability.
Data Source
AI summary
A hand-held power tool which includes a gear housing with a gear for transmitting a torque, generated by a drive motor, to a spindle. The gear housing is exchangeably connectable to a tool attachment via an interface in such a way that a torque is transmitted from the spindle to an input spindle of the tool attachment. The interface includes a housing-side interface element with a flange ring, which is connected to the gear housing in a torsionally stiff manner. The housing-side interface element corresponds to a tool attachment-side interface element which includes a fastening ring that is rotatably supported on the tool attachment. The fastening ring is brought into engagement with the flange ring by a coupled rotatory and axial relative movement of the fastening ring with respect to the flange ring so that the fastening ring and the flange ring together form a bayonet-type connector.