Three-Jaw Wrench Head for Confined Space Torque Measurement
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Solution Overview
Problem
Torque wrenches with crow's-foot extensions face difficulties in engaging and accurately measuring torque for tube-nuts in confined spaces within aircraft structures, making it challenging to ensure accurate assembly operations.
Innovation Solution
A wrench head design featuring a serial coupling of three jaws with arcuate and planar contact surfaces, allowing for placement over a fastener from a lateral direction, providing multiple regions of contact and preventing closure during ratcheting motion, thereby facilitating accurate torque application and measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque wrenches with crow's-foot extensions are used, then torque measurement capability is provided, but engagement difficulty increases in confined spaces
Solution Approach 1:
The wrench head is divided into three separately pivotable jaws (first jaw, second jaw, third jaw) that can be independently positioned and closed onto the fastener. This segmentation allows the jaws to be opened wide for easy engagement in confined spaces, then closed securely onto the fastener corners, resolving the contradiction between measurement capability and engagement difficulty.
Solution Approach 2:
The invention introduces a lateral placement dimension by allowing the wrench head to be positioned and engaged from a direction lateral to the fastener axis. The three-jaw configuration enables approach from angles that are not collinear with the fastener, providing access to confined spaces where traditional axial approach wrenches cannot reach.
2Device complexity
If traditional wrench designs are used, then simplicity is maintained, but contact regions with fastener are insufficient
Solution Approach 1:
Each jaw is equipped with specific contact surfaces (arcuate convex contact surfaces and planar contact surfaces) tailored for different functions: the arcuate surfaces engage the rounded corners of the fastener, while the planar surfaces contact the flat faces. This localized optimization of contact geometry ensures stable, multi-point engagement without requiring complex overall structure.
Solution Approach 2:
The three jaws are nested in a serial coupling arrangement where the second jaw is coupled to the first jaw and pivotable relative to it, and the third jaw is coupled to the second jaw and pivotable relative to it. This nested configuration allows compact storage when opened, yet provides distributed contact points when closed, improving reliability without excessive complexity.
3Productivity
If wrench head closes during ratcheting motion, then torque application continues, but fastener deformation occurs
Solution Approach 1:
The planar contact surfaces on each jaw are positioned and oriented to prevent closure during ratcheting motion by contacting the flat faces of the fastener head. These surfaces act as mechanical stops that counteract the closing force before it can transmit excessive load to the fastener corners, thereby preventing deformation while allowing continuous torque application through the ratcheting mechanism.
Solution Approach 2:
The invention changes the contact geometry parameters by introducing both arcuate convex surfaces (for corner engagement) and planar surfaces (for face contact). This parameter variation in contact surface geometry allows the wrench to maintain engagement during ratcheting without transmitting harmful closing forces, enabling continuous productivity without fastener damage.
Data Source
AI summary
A wrench head comprises a working axis, a first jaw, a second jaw, and a third jaw. The first jaw comprises a first-jaw arcuate convex contact surface, a second first-jaw arcuate convex contact surface, a third first-jaw arcuate convex contact surface, and a first-jaw planar contact surface. The second jaw is coupled with and pivotable relative to the first jaw and comprises a second-jaw arcuate convex contact surface, a second second-jaw arcuate convex contact surface, and a second-jaw planar contact surface. The third jaw is coupled with and pivotable relative to the second jaw and comprises a third-jaw arcuate convex contact surface and a third-jaw planar contact surface.