Lockable Jaw Assembly for Seismic-Resistant Cast-In Anchors
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Solution Overview
Problem
Conventional cast-in-place anchor assemblies experience axial movement and dynamic impacts during seismic events, leading to compromised connections between the jaws and anchor members, particularly in split nut designs, resulting in potential separation, fatigue, and loss of hold.
Innovation Solution
Incorporating an axially expandable jaw lock with a smaller radius that expands to a larger radius to prevent upward axial movement of the jaws relative to the anchor housing, and a separator with inclined projections to ensure proper jaw separation during anchor member insertion, enhancing the locking mechanism and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spring is used to bias the jaws upward during insertion, then the axial positioning flexibility and engagement process are enhanced, but the jaws may move axially during seismic events causing impact engagement and compromised connection
Solution Approach 1:
The jaw assembly transitions from a static locked position to a dynamic movable position during insertion, then returns to locked position after engagement. The spring enables temporary axial movement during insertion to facilitate jaw separation and anchor member engagement, then the jaw lock prevents further movement to secure the connection against seismic loads.
Solution Approach 2:
The jaw assembly is divided into functional segments: the jaws themselves, the spring mechanism, and the jaw lock. This segmentation allows each component to perform its specific function - jaws for engagement, spring for insertion flexibility, and jaw lock for securing the connection against movement.
2Adaptability or versatility
If the jaws are allowed to move axially within the anchor housing, then compliance flexibility is provided during insertion, but dynamic impacts can cause the threaded jaws to separate, fatigue, shear threads and lose hold of the anchor member
Solution Approach 1:
The system employs dynamic behavior during insertion where the jaws can move axially to accommodate compliance requirements, then transitions to a static locked state where the jaw lock prevents further movement. This dynamic-to-static transition ensures both insertion flexibility and operational strength.
Solution Approach 2:
The jaw lock is designed to engage the jaw assembly in advance before seismic or dynamic loads are applied. This preliminary locking action prevents the jaws from moving axially during subsequent loading events, avoiding thread fatigue and separation.
3Reliability
If a washer and nut are used on the threaded rod to transfer load directly to the metal decking, then the load is not transferred through the jaws, but this adds device complexity and requires additional components
Solution Approach 1:
The jaw assembly is designed to serve multiple functions: engaging the anchor member during insertion, securing the connection through the jaw lock, and transferring loads during normal operation. This multi-functionality eliminates the need for separate washers and nuts, reducing component count while maintaining reliable load transfer.
Solution Approach 2:
The functions of jaw engagement, load transfer, and connection securing are merged into a single integrated jaw assembly with jaw lock mechanism. This consolidation replaces the separate washer and nut components, simplifying the overall device while ensuring reliable load transfer from the anchor member through the jaws to the anchor housing.
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 jaw lock immobilizes the jaws relative to the anchor housing, preventing dynamic impacts and ensuring a secure connection by transferring loads directly through the jaws to the anchor housing and concrete, thereby enhancing the durability and reliability of the anchor assembly.
Implementation Method 1
an expandable member which has a first smaller radius and which is capable of expanding to a second larger radius
Data Source
AI summary
An anchor assembly is disclosed for suspending objects to a concrete structure. The assembly includes an anchor housing having a jaw assembly therein and a opening for receiving an anchor member such as a threaded rod. The jaw assembly includes threaded rods having a threaded opening, a wood form anchor assembly and a metal decking anchor assembly. The wood form and the metal decking anchor assemblies may accommodate the anchor housing and the anchor housing is used in one of the wood form anchor assembly and the metal decking anchor assembly. The metal decking anchor assembly includes a nose-piece and the anchor housing is selectively connectable to the nose-piece via a locking connection such as a bayonet connection.