Reciprocating Tool Blade Clamp With Automatic Locking Ejector Pin
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Solution Overview
Problem
Existing blade clamps for power tools, such as jigsaws, require manual adjustment between locked and unlocked configurations, which can be inconvenient and may not automatically secure the blade properly during insertion.
Innovation Solution
A blade clamp design featuring a cover threaded to the spindle with a spring coupling and an ejector pin that automatically adjusts from an unlocked to a locked configuration upon blade insertion, utilizing a torsion spring to bias the cover into a locked position and a compression spring to maintain the unlocked state, allowing the cover to rotate and secure the blade.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual adjustment is used to switch between locked and unlocked configurations, then the blade clamp structure remains simple, but the ease of operation deteriorates due to inconvenient manual adjustment
Solution Approach 1:
The blade clamp automatically transitions between unlocked and locked configurations through the interaction of the ejector pin, spring, and cover mechanism. When the blade is inserted, the ejector pin is pushed into the cover, releasing the lock and allowing the spring to automatically rotate the cover to the locked position, eliminating the need for manual adjustment by the user
Solution Approach 2:
The spring is pre-loaded to store rotational energy that automatically engages the locking mechanism. The ejector pin is pre-positioned to engage with the cover in the unlocked state, and upon blade insertion, the pin's movement triggers the automatic locking sequence without requiring user intervention
2Reliability
If automatic locking mechanism is implemented, then the reliability of blade attachment improves, but the device complexity increases due to additional components
Solution Approach 1:
The system uses the insertion force of the blade itself to trigger the locking mechanism. The ejector pin is pushed by the blade stem, which automatically releases the cover from the unlocked to locked position through spring action, making the blade's own insertion motion the triggering mechanism for secure attachment
Solution Approach 2:
The locking and unlocking functions are merged into a single automatic sequence triggered by blade insertion. The spring both provides the locking force and drives the cover rotation, while the ejector pin serves both as a position indicator and the trigger mechanism, reducing the need for separate complex locking components
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 one-handed blade insertion and automatic locking, ensuring secure blade attachment without manual adjustment, enhancing user convenience and reliability of the blade clamp.
Implementation Method 1
a spring coupling the cover and the spindle. The spring biases the cover toward a first rotational position relative to the spindle coinciding with a locked configuration of the blade clamp
Implementation Method 2
The cover is rotatable against the bias of the spring toward a second rotational position relative to the spindle coinciding with an unlocked configuration of the blade clamp
Data Source
Figure 1
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AI summary
A blade clamp for use with a power tool having a reciprocating spindle. The blade clamp comprises a cover threaded to the spindle for relative axial movement thereto in response to rotation of the cover relative to the spindle, an ejector pin positioned within the spindle, and a spring coupling the cover and the spindle. The spring biases the cover toward a first rotational position relative to the spindle coinciding with a locked configuration of the blade clamp. The cover is rotatable against the bias of the spring toward a second rotational position relative to the spindle coinciding with an unlocked configuration of the blade clamp. In the unlocked configuration, the ejector pin maintains the cover in the second rotational position. In response to insertion of a blade into the spindle, the blade clamp is automatically adjustable from the unlocked configuration to the locked configuration.