Excentre Arm Wire Locking Mechanism for Slippery Rebar Tying
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Solution Overview
Problem
Existing automatic wire tying devices for rebars face challenges in securely holding slippery wires and achieving tight knots, especially when the wire is coated with substances like oil, water, or ice, and when the wire thickness varies.
Innovation Solution
A wire locking mechanism featuring a holding member and a counter-holding member with toothed wheels, supported by an excentre arm, which engages the wire at an acute angle to provide a firm grip and release it precisely, minimizing wire shaving and ensuring knot tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wire locking mechanisms are used, then the device structure is simple, but the mechanism cannot hold slippery wires firmly during knot formation
Solution Approach 1:
The wire locking mechanism is divided into multiple functional components: a holding member with a first toothed wheel, a counter-holding member with a second toothed wheel, and an excentre arm assembly. Each component performs a specific function in gripping and controlling the wire, allowing the complex task of holding slippery wires to be distributed across specialized segments rather than a single simple structure.
Solution Approach 2:
The excentre arm acts as an intermediary mechanism between the actuator and the toothed wheels. It converts rotational motion into the precise angular positioning required for the holding and counter-holding members to engage the wire at the correct acute angle, enabling reliable wire gripping without direct complex linkage between the actuator and wire contact points.
2Manufacturing precision
If the wire locking mechanism uses a simple holding structure, then the device is easy to manufacture, but it cannot achieve tight knots with minimal slack
Solution Approach 1:
The locking mechanism employs dynamic elements including rotatable toothed wheels on both the holding member and counter-holding member, along with an actuator that dynamically adjusts the excentre arm position. This dynamic configuration allows the mechanism to adapt to variations in wire thickness and tension, achieving consistent knot tightness across different wire conditions while maintaining reasonable manufacturing complexity.
Solution Approach 2:
The mechanism utilizes changeable geometric parameters, specifically the acute angle between the first axis and holding plane, which can be adjusted through the excentre arm rotation. This parameter change enables the mechanism to optimize wire engagement for different wire types and thicknesses, achieving precise knot control without requiring multiple fixed-configuration mechanisms.
3Adaptability or versatility
If the wire locking mechanism uses a fixed geometry, then the device is simple to operate, but it cannot adapt to wires with varying thickness along the length
Solution Approach 1:
The toothed wheels on both the holding member and counter-holding member serve multiple functions: they provide gripping surfaces for the wire, act as rotational elements for dynamic adjustment, and engage with the excentre arm mechanism. This multi-functionality allows a single mechanism design to handle wires of varying thickness without requiring separate adjustment mechanisms, maintaining ease of operation while achieving adaptability.
4Loss of substance
If the wire is released by simple mechanical separation, then the operation is quick, but there is significant build-up of wire shavings
Solution Approach 1:
The wire release mechanism replaces direct mechanical friction-based separation with a controlled disengagement of the toothed wheels from the wire. The actuator-driven excentre arm rotation smoothly withdraws the holding members from the wire, reducing abrasive contact and wire shaving while maintaining adequate release speed for productive operation.
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 mechanism effectively holds even slippery wires firmly during knot formation and releases them precisely, resulting in tight knots with minimal slack and reduced wire shaving, thus improving the efficiency and reliability of automatic rebar wire tying.
Implementation Method 1
The excentre arm is rotatably supported on a first shaft to rotate about an excentre arm center of rotation, wherein the holding member is arranged distanced along a first axis from the excentre arm center of rotation, the first axis forming an acute angle with the holding plane when in the locking position
Implementation Method 2
The holding member comprises a first toothed wheel rotatably supported on a second shaft... arranged to engage respective sides of the wire to releasably hold the wire in a locking position
Data Source
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AI summary
A wire locking mechanism (200, 300, 400, 500, 600, 700) for a reinforcement bar, rebar, wire tying device (100), the locking mechanism comprising (200, 300, 400, 500, 600, 700) a holding member (210, 310) and a counter-holding member (220, 320) arranged to engage respective and opposite sides of a wire (230) to releasably hold the wire (230) in a locking position, where a holding force exerted on the wire (230) by the holding member (210, 310) is normal to a holding plane (A2), wherein the holding member (210, 310) is supported on a first end of an excentre arm (240, 340), the excentre arm (240, 340) being rotatably supported on a first shaft (250, 350) to rotate (R1) about an excentre arm center of rotation (255, 355), wherein the holding member (210, 310) is arranged distanced (D) along a first axis (A1) from the excentre arm center of rotation (255, 355), the first axis (A1) forming an acute angle (A) with the holding plane (A2) when in the locking position.