Quick-Release Mandrel Assembly for Reliable Rotary Tool Clamping
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Solution Overview
Problem
Existing hand-held rotary tools require additional tools or complex mechanisms to secure accessories, such as clamping screws or lever-operated quick connection clamps, which add weight, complexity, and cost.
Innovation Solution
A mandrel assembly with a quick-connect/quick-release mechanism using a clamping action between a clamping element on the mandrel and a spring-biased collar, where the accessory is secured via a scalloped slot path that allows both axial and rotational movement to transition between locked and unlocked configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamping screw mechanism is used to secure the accessory to the mandrel, then the connection reliability is improved, but the device complexity and the need for additional tools increase
Solution Approach 1:
The patent removes the clamping screw from the system entirely, replacing it with a collar-based clamping mechanism that integrates directly into the mandrel assembly. This extraction eliminates the need for separate fastening tools while maintaining secure accessory attachment through the collar's interference fit and clamping action.
Solution Approach 2:
The collar-based mechanism is designed to be self-operating through a simple rotational motion that transforms axial movement into clamping force. The user directly manipulates the collar to attach or detach accessories without requiring external tools or complex actuation mechanisms, making the system self-sufficient.
2Ease of operation
If a lever-operated quick connection clamp is used to secure the accessory, then the ease of operation is improved, but the weight and device complexity increase
Solution Approach 1:
The patent eliminates the lever mechanism entirely, replacing it with a collar that operates through direct rotational manipulation. This removal of the lever component significantly reduces the weight of the mandrel assembly while maintaining quick and easy accessory attachment through the simplified rotational clamping action.
Solution Approach 2:
Instead of using a lever that amplifies force through mechanical advantage, the patent inverts the approach by using a collar where rotational motion directly generates the clamping force through geometric transformation. The axial movement of the collar during rotation creates the clamping action without requiring force amplification mechanisms.
3Manufacturing precision
If a threaded aperture with clamping screw is used, then the manufacturing precision can be maintained, but the ease of manufacture decreases
Solution Approach 1:
The patent removes the threaded aperture and clamping screw assembly, replacing it with a collar that engages directly with the mandrel through a simplified geometric interface. This eliminates complex threading operations and multiple component assembly steps, making the manufacturing process simpler while maintaining precise accessory positioning through the collar's designed geometry.
Solution Approach 2:
The collar integrates multiple functions into a single component: it provides the clamping action, the positioning feature, and the operational interface. This merging of functions into one piece reduces the number of parts that need to be manufactured and assembled, simplifying production while maintaining the precision required for secure accessory attachment.
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 easy and tool-free attachment and detachment of accessories, reducing weight, complexity, and cost while providing a reliable and stable connection, allowing for efficient operation of rotary tools.
Implementation Method 1
a spring-biased collar, where the accessory is secured via a scalloped slot path
Implementation Method 2
The spring surrounds the mandrel and extends between the retention washer and the collar inner shoulder
Data Source
AI summary
A mandrel assembly may be used with a rotary power tool to provide a reliable and stable connection between the rotary tool and a tool accessory. The mandrel assembly provides a quick-connect/quick-release connection between the tool output shaft and the accessory via a clamping action. In particular, the mandrel assembly is movable between a first configuration in which the accessory may clamped tween a clamping element formed on one end of the mandrel and a collar which surrounds the mandrel and a second configuration in which the accessory may be loaded onto or detached from the mandrel assembly. Movement from the first configuration to the second configuration, and from the second configuration to the first configuration each include axial motion in combination with a rotation of the mandrel in the same direction relative to the collar.