Folding Knife Ejector Bar for Controlled Blade Restraint
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Solution Overview
Problem
Existing folding knives with replaceable blades often experience blade slippage during use, posing safety hazards due to unrestrained detachment, especially in slippery or greasy conditions, and are difficult to safely eject under such conditions.
Innovation Solution
A folding knife design featuring a blade holder with a pivotable mechanism and an ejector bar that allows blade detachment only in an intermediate position, constrained in open and closed positions to prevent accidental ejection, ensuring safe handling and easy blade replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the blade is made replaceable to maintain sharpness during extended use, then the knife can be replaced in the field, but the blade becomes unrestrained and may slip out of the handle during manipulation
Solution Approach 1:
The blade holder is designed with a dynamic locking mechanism that transitions between locked and unlocked states. The lock element engages with the blade holder body to restrain the blade during normal use, and can be actuated to release the blade for replacement. This dynamic state change allows the system to provide both reliable restraint during operation and ease of replacement when needed.
Solution Approach 2:
A lock element serves as an intermediary component between the blade holder and the blade. This lock element provides the restraining force to secure the blade in place during use, while also serving as the mechanism for controlled release during replacement. The lock element mediates between the need for secure blade retention and the need for easy replacement.
2Ease of operation
If the blade can be easily removed by lifting the rear of the blade, then blade replacement is simple, but the hand may slip on slippery surfaces exposing the user to injury
Solution Approach 1:
The lock element acts as an intermediary that provides a safe interface for blade removal. Instead of requiring direct hand contact with the blade rear end, the user interacts with the lock element which is designed to be gripped safely. The lock element mediates the removal process, providing mechanical advantage while maintaining safe hand positioning away from the sharp blade edge.
Solution Approach 2:
The locking mechanism is designed to be self-actuating through a simple lifting motion. When the user lifts the rear of the blade, the lock element automatically engages with the blade holder body to secure the blade. The system serves itself by using the blade's own weight and position to trigger the locking action, eliminating the need for separate manual locking steps.
3Adaptability or versatility
If the blade holder allows free movement between open and closed positions, then the knife is flexible in deployment, but the blade may accidentally detach during manipulation
Solution Approach 1:
The blade holder incorporates a dynamic locking mechanism that remains engaged during normal movement between open and closed positions, and only releases when deliberately actuated. The lock element maintains continuous contact with the blade holder body, providing ongoing restraint while allowing controlled deployment. This dynamic design ensures blade security during manipulation while preserving operational flexibility.
Data Source
AI summary
Folding knives have an elongated frame, a blade holder pivotally connected to the elongated frame to move between a closed position and an open position, the blade holder having a blade mount facility configured to removably receive a blade, and an ejector movably connected to the blade holder and operable to detach the blade when the blade is received on the blade mount facility. The blade holder may be operable to move to an intermediate position between the open and closed position, and the ejector may be operable to detach a blade only in the intermediate position. The ejector may be constrained to render the ejector inoperable to detach a blade in the open position. The ejector may be constrained to render the ejector inoperable to detach a blade in the closed position. The ejector may be an elongated bar.