Oversized Threaded Rod Locking for Height-Adjustable Oblong Holes
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Solution Overview
Problem
Existing methods for securing a first part with a locking oblong hole to a second part lack an efficient mechanism for height-adjustable securement.
Innovation Solution
The method involves using an oversized locking threaded rod that widens the locking oblong hole as it is passed through, creating an undercut for a secure engagement, and optionally using a pre-fixing threaded rod to provide initial securement without widening the hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an oversized locking threaded rod is used to widen the locking oblong hole for tight fixation, then the fixation strength is improved, but the first part may be lifted off the second part during the widening process
Solution Approach 1:
A pre-fixing threaded rod is inserted through the pre-fixing oblong hole before the locking threaded rod to secure the first part to the second part in advance. This preliminary fixation prevents the first part from being lifted during the subsequent hole-widening process when the oversized locking threaded rod is inserted.
Solution Approach 2:
The fastening process is divided into two distinct stages: pre-fixing using a pre-fixing threaded rod through a pre-fixing oblong hole, and then locking using a locking threaded rod through a locking oblong hole. This segmentation allows the pre-fixing stage to stabilize the connection before the locking stage widens the hole for tight fixation.
2Reliability
If the locking threaded rod is oversized with respect to the locking oblong hole width, then engagement reliability is improved through material displacement interlock, but the manufacturing precision requirement increases
Solution Approach 1:
The insertion of the oversized locking threaded rod intentionally causes controlled material displacement and plastic deformation of the hole walls. This previously harmful effect is converted into a beneficial interlock mechanism where the displaced material creates an undercut that mechanically locks the threaded rod in place, enhancing engagement reliability.
Solution Approach 2:
The locking threaded rod is designed with dimensions that exceed the nominal hole dimensions, creating a deliberate size mismatch. This parameter change enables the rod to actively reshape the hole during insertion, transforming a precision-machined hole into a form-fitted, interlocked connection that is more reliable than a perfectly precise fit.
3Stability of the object's composition
If a pre-fixing threaded rod is used to secure parts before widening, then position stability is improved, but the device complexity increases with additional components
Solution Approach 1:
Both the pre-fixing threaded rod and the locking threaded rod are designed with identical dimensions and thread specifications. This universality allows the same type of fastener to serve dual purposes: initial positioning and final locking, simplifying inventory and selection while maintaining functional differentiation through the two-hole system.
Data Source
AI summary
A method for securing a first part to a second part where the first part has a locking oblong hole. The method includes passing a locking threaded rod through the locking oblong hole and into the second part. The locking threaded rod is oversized with respect to a width of the locking oblong hole such that the locking threaded rod widens the locking oblong hole as the locking threaded rod is passing through the locking oblong hole.