Knife Blade Unit Slide Guidance for Housing Damage
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Solution Overview
Problem
Safety knives with automatic blade retraction often malfunction due to excessive stressing, particularly when the knife housing is damaged or deformed, leading to a risk of injury and unintentional damage.
Innovation Solution
A knife design featuring a moveable slide member that mounts the blade unit rotatably, eliminating the need for housing-guided blade unit longitudinal guidance and incorporating a non-rotatable slide member to prevent tilting and a latching mechanism for safe movement control, along with a retraction element to ensure automatic blade retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blade unit is guided by housing elements (pin in slot), then the blade unit can be longitudinally guided, but the guidance can fail when the housing is damaged or deformed by overstressing
Solution Approach 1:
The patent introduces a moveable slide member as an intermediary component between the blade unit and the housing. The blade unit is rotatably mounted on the slide member, which itself moves within the housing. This intermediary structure isolates the blade unit guidance from direct contact with the housing, preventing housing damage or deformation from directly affecting blade unit guidance reliability.
2Device complexity
If the blade unit is directly guided in the housing, then the structure is simple, but the knife is vulnerable to malfunction when overstressed
Solution Approach 1:
The patent segments the guidance system into two independent parts: the slide member that moves within the housing and the blade unit that rotates on the slide member. This segmentation allows each component to be optimized for its specific function and isolates potential failure points, improving overall reliability without excessive complexity.
3Ease of operation
If the blade unit can rotate freely, then cutting force can cause decoupling movement, but the blade unit may tilt or move uncontrollably
Solution Approach 1:
The patent implements a dynamic mounting system where the blade unit is rotatably mounted on the moveable slide member. This allows the blade unit to rotate for decoupling during cutting operations while the slide member provides dynamic support and prevents tilting or uncontrolled movement through its constrained motion within the housing.
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
The design significantly reduces the risk of malfunction and enhances robustness by avoiding contact between the blade unit and the housing, preventing malfunctions due to housing damage and ensuring safe automatic blade retraction.
Implementation Method 1
a retraction element (34) which always applies a retraction force to the blade unit in the direction of the retracted position
Data Source
AI summary
A knife (1) with automatic blade retraction including a housing (2), a moveable actuating device (4), a rotatable blade unit (30), and a retraction element (34) which always applies a retraction force to the blade unit (30) in the direction of the retracted position. The rotatable blade unit (30) can be brought into engagement with the actuating device (4) and is moveable by means of the actuating device (4) from a position retracted in the housing (2) into a position extended from the housing (2). The blade unit (30) is also rotatable by the action of a cutting force in an extended position from an engagement position in which the blade unit (30) is in engagement with the actuating device (4) into a release position in which the blade unit (30) is not in engagement with the actuating device (4).