Hinged Shrinkage Compensation Device with Ratchet Base Plate
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Solution Overview
Problem
Existing shrinkage compensation devices for building structures with wooden frames face issues such as complex installation, vulnerability to threading stripping, and limited strength due to metal-on-metal contact, as well as inconvenience in alignment and potential malfunction.
Innovation Solution
A hinged building shrinkage compensation device featuring a base plate with notches and a hinged expander mounted on it, utilizing a tension spring for axial bias to allow one-way motion of a take-up fastener, preventing upward movement and maintaining structural tightness, without requiring metal-on-metal threading engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a ratchet engagement device is used to prevent upward movement, then upward loads are resisted, but the metal-on-metal threading contact provides resistance that can lead to threading stripping
Solution Approach 1:
The patent introduces a ratchet mechanism as an intermediary between the fastener and the base plate. The ratchet engages with the fastener shank through a toothed interface that allows downward movement while preventing upward movement, eliminating direct metal-on-metal threading contact under load and preventing threading stripping
Solution Approach 2:
The patent replaces the traditional threaded mechanical connection with a ratchet-tooth mechanical engagement system. Instead of relying on friction and threading resistance, the system uses a geometric interlocking mechanism where the ratchet teeth physically block upward movement while allowing downward movement, providing more reliable load resistance
2Strength
If coil straps are used to anchor upper levels to lower levels, then anchoring is achieved, but alignment of vertical studs on adjacent floors is required
Solution Approach 1:
The patent changes the geometric parameters of the connection interface by using a ratchet mechanism with adjustable tooth engagement. The fastener can engage with the ratchet at various positions along its length, allowing accommodation of stud misalignment while maintaining anchoring strength, eliminating the need for precise vertical stud alignment
3Reliability
If a compensation device with ratchet engagement is used, then upward movement is prevented, but the device complexity increases
Solution Approach 1:
The patent segments the compensation device into distinct functional components: a base plate with integrated ratchet teeth, a fastener with shank, and optional washers. This segmentation allows each component to be simple in itself while achieving complex functionality through their interaction, making the device easier to manufacture and assemble
Solution Approach 2:
The patent merges the ratchet mechanism directly into the base plate structure, eliminating the need for separate ratchet components. The ratchet teeth are formed as an integral part of the base plate, reducing the number of parts and simplifying the overall device while maintaining the one-way movement prevention function
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides easy installation, enhanced strength, and reduced risk of malfunction by allowing the take-up fastener to move freely upward, effectively compensating for wood shrinkage and resisting upward loads, while preventing collapse and maintaining structural integrity.
Implementation Method 1
The expander is biased axially away from the base plate substantially at the axis
Data Source
AI summary
A device for compensating for the natural shrinkage of building materials includes an expander mounted on a base plate. An opening in the expander aligns with a hole in the base plate to define an axis and receive a shank of a fastener. The expander is biased axially away from the base plate substantially at the axis. The base plate can be securely fastened to a first building member. A fastener can be axially fixed relative to a second building member and the expander but not axially fixed relative to the base plate and first building member.