Retractable Knife Blade Stabilization via Movable Wedge Carriage
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Solution Overview
Problem
Existing knives with retractable blades often suffer from uncontrolled bending and breaking due to bending stress, leading to unstable cutting performance and potential blade failure during extended use.
Innovation Solution
A knife design featuring a blade moving carriage with a wedge carriage part that can move relative to the carriage part, utilizing a latching mechanism with evenly distributed locking recesses for stabilization, and an optional reinforcing part that can be moved independently or in conjunction with the blade to counteract bending stress, ensuring precise cutting and extended blade life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the blade is extended beyond the handle for use, then the cutting functionality is improved, but the blade becomes susceptible to bending stress and uncontrolled breaking
Solution Approach 1:
The blade is divided into multiple segments with predetermined breaking points, allowing controlled breakage into usable portions. This segmentation prevents uncontrolled breaking while maintaining reliability during extended use.
Solution Approach 2:
The blade carriage includes a wedge carriage part that can move relative to the carriage part in the longitudinal direction, allowing dynamic adjustment and locking of the blade at different extension positions. This dynamic mechanism enables the blade to be securely held at various extended positions while preventing unwanted movement that could cause breaking.
2Manufacturing precision
If the blade is made rigid for precise cutting, then cutting precision is improved, but the blade becomes more prone to breaking under bending stress
Solution Approach 1:
The wedge carriage part can move and lock at different positions along the blade, dynamically adjusting the support point to match the extended length. This provides optimal rigidity and cutting precision for each extension position while distributing bending stress to prevent breaking.
Solution Approach 2:
The blade is segmented with predetermined breaking points that allow controlled breakage into smaller, more manageable sections. This maintains cutting precision for each segment while preventing catastrophic failure under bending stress.
3Length of moving object
If the blade is extended to increased length, then the working range is improved, but the bending stress and risk of breaking increase
Solution Approach 1:
The wedge carriage part can be positioned and locked at various longitudinal locations corresponding to different blade extension lengths. This dynamic positioning allows the blade to be used at different lengths while maintaining stability and preventing breaking at each position.
Solution Approach 2:
The blade is divided into segments with predetermined breaking points, enabling the blade to be broken into appropriate lengths after use. This ensures that even when extended to increased lengths, the blade can be safely divided into manageable sections that maintain durability.
4Reliability
If a locking mechanism is added to secure the extended position, then blade stability is improved, but the device complexity increases
Solution Approach 1:
The wedge carriage part itself serves as the locking mechanism, moving dynamically to engage with the carriage part at different longitudinal positions. This integrated dynamic locking mechanism provides stability without requiring separate complex locking components.
Solution Approach 2:
The wedge carriage part combines multiple functions: it supports the blade, allows longitudinal movement for extension adjustment, and provides locking capability through its interaction with the carriage part. This merging of functions reduces overall device complexity while maintaining reliability.
Data Source
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AI summary
The invention relates to a knife (12) with a knife handle (2) and a blade(3), said blade (3) being extendable and retractable in relation to the knife handle (2). The aim of the invention is to improve a knife of this type in respect of its handling. For this purpose, a reinforcing part (57) is provided which can support an extended portion of the blade (3), the reinforcing part (57) being movable in respect of the knife handle (2) and being detachably connected to the blade (3). Another solution is that the knife (1) has a blade-moving carriage (30) and/or a reinforcing part-moving carriage (31) and that a latching holder for latch-adjusting different extended positions of the blade (3) is provided, said latching structure being formed below the region in which the blade (3) or an imaginary continuation of the blade (3) extends, when seen from the blade-moving carriage (30) and/or the reinforcing part-moving carriage (31). In another embodiment, the blade-moving carriage (30) has a holding magnet (56) for holding cooperation with the blade (3). In yet another embodiment, a closing cap (11) is arranged on the knife handle (2) at the rear end of the blade (3), said closing cap closing the movement path for the blade-moving carriage (30) and/or the reinforcement part-moving carriage (31).