Rotary Tool Mandrel Locking Structure for Quick Accessory Coupling
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Solution Overview
Problem
Rotary tools lack an efficient mechanism for quickly and securely coupling and decoupling accessories, leading to inconvenience and potential loss of torque transmission efficiency.
Innovation Solution
A mandrel design featuring a shaft with radially protruding locking projections and a collar with angularly offset coupling projections, along with a nut that threads onto the shaft to move the locking projections toward the coupling features, allowing for secure attachment and detachment of accessories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional coupling mechanisms are used, then accessory attachment is secure, but coupling and decoupling process is time-consuming and inconvenient
Solution Approach 1:
The coupling mechanism is segmented into distinct functional elements: locking projections on the shaft, coupling projections on the collar, and corresponding mating features on the accessory. This segmentation allows each element to perform its specific function independently, enabling quick alignment and engagement without complex manipulation
Solution Approach 2:
The locking projections and coupling projections are pre-positioned on the shaft and collar respectively, in angularly offset positions. This preliminary arrangement ensures that when the accessory is brought to the mandrel, the projections are already in optimal positions for engagement, eliminating the need for manual alignment adjustments during coupling
2Productivity
If quick coupling mechanism is implemented, then accessory attachment is fast, but torque transmission reliability may be compromised
Solution Approach 1:
The locking and coupling functions are merged into a single engagement action. The locking projections engage with the accessory's mating features while the coupling projections simultaneously engage with corresponding features, creating a unified mechanical connection that provides both quick attachment and reliable torque transmission
Solution Approach 2:
The locking projections and coupling projections are designed with specific curved profiles that match complementary curved surfaces on the accessory. This curvature design allows for smooth engagement while distributing mechanical stresses evenly across the contact surfaces, enhancing torque transmission reliability
3Reliability
If multiple projections are used for secure coupling, then attachment reliability improves, but device complexity increases
Solution Approach 1:
Both the locking projections and coupling projections are integrated into the same collar assembly, serving dual functions of securing the accessory and transmitting torque. This multi-functionality reduces the need for separate components, maintaining attachment security while controlling structural complexity
Data Source
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AI summary
A rotary tool mandrel includes a shaft, locking projections, a collar, and a fastener. The shaft extends along a longitudinal axis and includes a distal end. The locking projections protrude radially relative to the longitudinal axis and positioned on opposite sides of the longitudinal axis from one another. Each of the locking projections define a locking projection outer profile that is rectilinear. The collar is coupled to the shaft and includes a pair of coupling projections protruding from a surface of the collar adjacent the distal end of the shaft. The coupling projections are angularly offset from the locking projections with respect to the longitudinal axis. Each of the coupling projections define a coupling projection that is rectilinear. The fastener is coupled to the shaft and movable relative to the shaft along the longitudinal axis, and movement of the fastener causes the locking projections to move toward the coupling projections.