Chalk Box Spool Groove Anchoring Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional chalk box designs are limited by the minimum spacing requirements between the spool and housing components, which impact the overall size and weight of the device, and are prone to string fraying or failure at the anchoring point.
Innovation Solution
The improved spool design features a core member with sidewalls that include anchorage orifices and a spool groove on the outside surface, allowing for reduced clearance between the spool and housing while securely retaining the string, thereby optimizing geometric characteristics and preventing string damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the string is passed through openings in the spool for anchoring, then the string can be securely tied to the spool, but the minimum spacing between the spool and housing components increases, resulting in larger overall device size
Solution Approach 1:
The patent transitions the string anchoring method from a two-dimensional surface arrangement (openings on the spool surface) to a three-dimensional groove configuration. The groove provides depth and vertical space, allowing the string to be anchored within the groove structure rather than requiring horizontal clearance on the spool surface. This dimensional change enables reduced spacing between the spool and housing components while maintaining secure string anchoring.
2Reliability
If the string is passed through openings in the spool for anchoring, then the string can be tied to the spool, but the overall size and weight of the chalk box increases
Solution Approach 1:
The groove configuration utilizes the third dimension (depth) to achieve secure string anchoring, eliminating the need for increased horizontal dimensions. This allows the chalk box to maintain a more compact overall size and reduced weight while still providing reliable string anchoring through the groove structure.
3Ease of manufacture
If the string is exposed on the outside of the spool for anchoring, then the string can be tied to the spool, but the string is prone to fraying or failing at the anchoring location
Solution Approach 1:
The patent embeds the string anchoring function within the groove structure of the spool. The groove acts as a protective enclosure that contains and protects the string at the anchoring location, similar to how a nested doll protects its contents. This nesting approach shields the string from external forces that cause fraying and failure, while still allowing for simple anchoring within the groove.
Solution Approach 2:
The groove structure provides beforehand protection to the string at the anchoring location. By pre-configuring the groove to contain and protect the string before use, the design prevents fraying and failure that would otherwise occur at the exposed anchoring points. This prior cushioning approach enhances string durability without complicating the anchoring process.
Data Source
AI summary
A spool for a chalk box may include a core member extending substantially parallel to an axis of rotation of the spool, a first sidewall disposed in a plane substantially perpendicular to the axis of rotation of the spool at a first end of the core member, and a second sidewall disposed in a plane substantially parallel to the first sidewall at a second end of the core member. The string may be configured to be retained on the spool by being wound onto the core member. The first sidewall may include a first anchorage orifice and a second anchorage orifice spaced apart from each other and each passing through the first sidewall from an inside surface of the first sidewall to an outside surface of the first sidewall. A spool groove may be formed on the outside surface of the first sidewall extending from the first anchorage orifice to the second anchorage orifice.