Circular Knitting Machine Cylinder Synchronization
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Solution Overview
Problem
Existing circular knitting machines face costly and complex mechanical transmission systems for synchronizing the rotation of cylinders, leading to potential misalignment and catastrophic needle breakages, which are costly and time-consuming to service.
Innovation Solution
The use of two separate electric motors, each with a dedicated PID controller, for controlling the rotation of the lower and upper cylinders, allowing for precise synchronization without the need for expensive gear transmissions, and ensuring safe stopping in case of motor failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a unique electric motor with mechanical transmission is used to drive both cylinders, then the structure is simpler, but the manufacturing cost increases and mechanical losses occur
Solution Approach 1:
The patent divides the drive system into two independent electric motors, each dedicated to driving one cylinder. This segmentation eliminates the need for complex mechanical transmission components like gears and belts, directly reducing manufacturing cost while maintaining structural simplicity through electronic control.
Solution Approach 2:
The patent replaces the mechanical transmission system with an electronic control system. Two independent electric motors are controlled electronically to achieve synchronized rotation of both cylinders, eliminating mechanical losses and reducing manufacturing complexity.
2Reliability
If a mechanical transmission system is used to synchronize cylinder rotation, then the alignment can be maintained, but the system becomes expensive and difficult to service
Solution Approach 1:
The patent replaces the mechanical transmission system with independent electric motors controlled by electronic synchronization. This eliminates mechanical components that require servicing while maintaining reliable cylinder alignment through electronic control of motor speeds and positions.
Solution Approach 2:
The patent implements electronic feedback control to monitor and adjust the rotation of each cylinder independently. This ensures precise alignment is maintained without requiring complex mechanical linkages, making the system more reliable and easier to service.
3Adaptability or versatility
If phase shift between cylinders is needed for knitting effects, then the knitting versatility increases, but the mechanical transmission becomes even more complicated
Solution Approach 1:
The patent uses two independently controlled electric motors, allowing each cylinder to be rotated at different speeds and phases. This enables various knitting effects like diagonal patterns and cable effects without requiring complex mechanical phase-shifting mechanisms.
Solution Approach 2:
The patent implements dynamic control of cylinder rotation through electronic speed and phase adjustment of the two motors. This allows real-time modification of the phase relationship between cylinders to create different knitting patterns, replacing static mechanical phase-shifting mechanisms.
Data Source
Figure 1
AI summary
Method for controlling the rotation of a lower cylinder (2) and a upper coaxial counter part (3) of a circular knitting machine, method comprising the steps of: - driving with a first electric motor (M1)the rotation of the lower cylinder (2), - driving with a second electric motor (M2) the rotation of the upper counterpart (3), - detecting the angular position (ϕ1) of the lower cylinder (3), - detecting the angular position (ϕ1) of the upper counter part, - controlling electronically the rotation of the first (M1) and second (M2) motors by determining of a first set-point S1 for the first motor and a second set-point S2 for the second motor according to: - the main set-point S provided by the knitting program, - the difference between the detected position ϕ1 of the lower cylinder and the detected position ϕ2 of the upper counter part, - and eventually the desired phase shift ξ between the lower cylinder and the upper counter part provided by the knitting program. Knitting machine implementing such method.