Knitting Needle Driving Cam Chamfered Edge Seizure Prevention
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Solution Overview
Problem
In flatbed knitting machines, the knitting operation butts and stitch transferring butts are prone to seizure due to the tilting force applied by cam faces, especially at high speeds, leading to productivity issues and potential mechanical failures.
Innovation Solution
A knitting needle driving cam with a cam face that tilts relative to the carriage running direction, featuring a chamfered edge removal in a specific range to prevent seizure, providing a clearance and ensuring sufficient lubrication, and maintaining a steep angle to guide the butts effectively without increasing the cam's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the cam face tilts with respect to the carriage running direction to guide the butt, then the knitting needle can be driven to advance and retreat, but the tilting force causes seizure of the butt at high speeds
Solution Approach 1:
The patent applies a localized quality change by providing a lubricant supply port only in the specific region where the cam face tilts with respect to the carriage running direction. This localized lubrication targets the exact area where seizure occurs due to tilting force, without requiring changes to the entire cam structure. The lubricant supply port is positioned to deliver lubricant precisely to the contact point between the cam face and butt during the tilting guidance operation.
Solution Approach 2:
The patent introduces lubricant as an intermediary substance between the cam face and the butt. This lubricant acts as a mediator that reduces friction and prevents direct metal-to-metal contact in the tilting region, thereby preventing seizure while allowing the cam face to continue its tilting guidance function. The lubricant supply port serves as the delivery mechanism for this intermediary substance.
2Manufacturing precision
If the cam face tilts at a steep angle to guide the butt effectively, then the guidance precision is improved, but the tilting force increases causing seizure
Solution Approach 1:
The patent maintains the steep tilting angle for guidance precision by applying localized lubrication only to the tilting region through the lubricant supply port. This allows the cam face to retain its steep angle for precise butt guidance while the lubricant counteracts the increased tilting force, preventing seizure in the specific high-stress area without requiring reduction of the overall cam face angle.
Solution Approach 2:
The lubricant introduced through the supply port acts as an intermediary that enables the cam face to maintain its steep tilting angle for precise guidance. The lubricant reduces the frictional resistance in the tilting region, allowing the steep angle to be maintained without generating excessive tilting force that would cause seizure.
3Reliability
If lubricant is supplied to prevent seizure, then reliability is improved, but the structure becomes more complex
Solution Approach 1:
The patent minimizes structural complexity by providing lubricant supply functionality only in the specific region where seizure occurs, rather than implementing a comprehensive lubrication system for the entire cam. The lubricant supply port is integrated into the cam structure at the precise location where the cam face tilts, adding minimal complexity while targeting the specific reliability issue.
Solution Approach 2:
The patent extracts only the essential lubrication function needed to prevent seizure in the tilting region, rather than implementing a complete lubrication system. The lubricant supply port is provided specifically in the region where the cam face tilts with respect to the carriage running direction, separating the lubrication need from the rest of the cam structure and adding minimal complexity.
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3~4
AI summary
To provide a knitting needle driving cam and a flatbed knitting machine that can prevent seizure of a knitting needle to a butt in a simple structure. A cam member 40 for driving a knitting needle is generally plate-form and is mounted to a carriage reciprocating the surface of a needle bed 15. The cam member 40 has a groove cam 41 formed to face the surface of the needle bed 15 and having a cam wall face 43 that comes in contact with and guides a butt 48 protruding from a knitting member 46 housed in a needle groove 18 of the needle bed 15 to the outside of the needle groove 18. The groove cam 41 is provided with a chamfering 45, and the edge of the cam wall face 43 on the cam surface 42 side is removed. A butt 47 protrudes more than 2 mm from the surface of the needle bed 15. Between the surface of the needle bed 15 and the cam surface 42, a clearance S of 0.2 mm is provided. The edge is removed by the chamfering 45 in a range of 0.2 to 0.4 mm away from the cam face of the groove cam 41 to the thickness direction.