Utility Knife Extended Travel Carriage for Finger Safety
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Solution Overview
Problem
Utility knives with short handles pose a risk of finger injury due to the proximity of the lowermost finger to the work surface, especially when the handle is not held at the proper angle, as the existing designs have limited blade carriage extension and require a two-handed operation for extending the blade, leading to insufficient finger elevation.
Innovation Solution
A utility knife with a short handle and an externally mounted carriage that extends to increase the handle length by a significant incremental length, allowing single-handed operation and positioning the lowermost finger at least 1.0 inch above the work surface, even when deviating from the optimal angle, through a button actuated by the thumb and ergonomic indentations for comfort and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the handle length is reduced to make the knife more portable and comfortable to hold, then the portability and comfort are improved, but the lowermost finger proximity to the work surface increases causing safety risks
Solution Approach 1:
The handle is segmented into two functional parts: a short stationary handle body for portability and comfort, and an extendable carriage that can be deployed when needed. This segmentation allows the knife to maintain a compact form factor while providing extended functionality for safety during cutting operations.
Solution Approach 2:
The carriage is designed to be dynamically extendable from the handle, transforming the static handle length into a variable dimension. When the carriage is extended, it increases the effective handle length to elevate the finger above the work surface; when retracted, it maintains the compact size for portability.
2Volume of moving object
If the carriage is fully retracted within the handle to contain the cutting portion, then the compactness is improved, but the incremental length change when extended is limited reducing finger elevation effectiveness
Solution Approach 1:
The carriage is nested within the handle when not in use, with the blade carriage housed inside the handle body. This nesting arrangement allows the carriage to be fully contained within the handle's external dimensions while still providing sufficient travel distance when extended to effectively elevate the finger above the work surface.
Data Source
AI summary
A utility knife has a handle generally defining a handle axis and a remote end provided with an opening. A carriage is slidably mounted within the handle for selective movements through the opening between a retracted position in which the carriage is substantially fully received within the handle and a fully extended position in which the carriage is fully extended through the opening to increase the effective length of said handle by a distance Δl. A blade mounted on the carriage shares the movements of the carriage and has an operative portion that can fully penetrate a work to be cut when the handle axis is inclined at an angle α relative to a surface of the work. A finger of a user most proximate to the work surface is positionable a distance h above the work surface during normal use of the utility knife, Δl and α being selected so that the distance Δl is generally greater that 1.0 inch and the angle α is equal to at least 35°.