Cutout Bolt Head for Chip-Breaking Temporary Fasteners
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Temporary fasteners used in manufacturing often cause damage to workpieces during drilling due to large chip formation, which can lead to scratching or binding of drill bits, and lack efficient sheet takeup capabilities, necessitating additional alignment methods and higher costs.
Innovation Solution
A tacking fastener with a stem and collar design featuring a head with multiple evenly spaced cutouts, allowing for reduced chip size during drilling and enhanced sheet takeup, preventing damage and facilitating easier installation and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If temporary fasteners are drilled out for removal, then removal is achieved, but large chips break off causing damage to workpieces and binding of drill bits
Solution Approach 1:
The head is segmented into multiple sections by forming grooves or slots that divide the head into discrete segments. During drilling removal, these segments break into smaller, manageable pieces rather than large chips, reducing workpiece damage and drill bit binding
Solution Approach 2:
The drilling process that normally creates harmful large chips is converted into a beneficial process where the grooves guide the breakage into controlled small segments. The harmful chip formation is transformed into useful segment separation that prevents damage
2Force
If temporary fasteners have strong sheet takeup capability, then workpieces are pulled together effectively, but fastener strength requirements increase cost
Solution Approach 1:
The fastener design incorporates a collar and stem mechanism that provides dynamic load distribution. The collar engages with the stem to create a mechanical advantage system that multiplies the pulling force, achieving strong sheet takeup without requiring proportionally higher fastener strength
Solution Approach 2:
The solution moves from a single-dimension strength approach to a multi-dimensional mechanical system involving collar-stem engagement. This dimensional change creates leverage and force multiplication, reducing the base strength requirement while maintaining effective sheet takeup
3Ease of manufacture
If temporary fasteners are simple in design, then manufacturing cost is reduced, but sheet takeup capability may be insufficient
Solution Approach 1:
The collar nests over the stem in a telescoping arrangement, creating a compact yet mechanically complex structure. This nested design achieves sophisticated force multiplication and load distribution without requiring separate components or complex assembly, maintaining manufacturing simplicity while enhancing sheet takeup capability
Data Source
AI summary
Two piece tack rivets and method of forming holes for permanent fasteners. The tack rivets have a stem with a head on one end and a grooved region adjacent the other end, and a locking collar for fitting over the grooved region of the stem for deforming into the grooved region of the stem on applying a setting force between the locking collar and the stem. The head includes cutouts formed therein. The cutouts prevent the head from forming large chips or strips when drilled.