Circular Knitting Machine Needle Drive Chain Axial Actuation
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Solution Overview
Problem
Existing circular knitting machines have limitations in size, which restrict their ability to manufacture fabrics with small diameters, limit needle movements, and reduce production flexibility, especially when operating with alternating oscillatory motion, due to large axial and circumferential sizes and the need for extensive actuating mechanisms.
Innovation Solution
A circular knitting machine design with a needle-holding cylinder featuring longitudinal grooves and a drive chain comprising a sub-needle, selector, and punch, where the selector and punch paths are optimized to allow for tuck and drop stitch formation in reduced circumferential spaces, enabling more movements and yarn feeds with a smaller diameter, and incorporating a selecting device with levers for alternating rotary motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional actuating mechanisms are used in circular knitting machines, then needle movement control is achieved, but the machine size becomes large and cannot manufacture fabrics with small diameters
Solution Approach 1:
The patent repositions the actuating mechanism from a radial arrangement to an axial arrangement along the needle cylinder. The cam is positioned axially above the needle cylinder and actuates needles through axial grooves, transforming the traditional radial actuation into axial actuation. This dimensional change allows compact machine design while maintaining full needle control capability for various stitch types.
Solution Approach 2:
The actuating mechanism is segmented into independent components: a cam with multiple paths, axial grooves in the needle cylinder, and individual needle actuation through these grooves. Each needle can be independently controlled through its own axial groove and cam interaction, enabling flexible stitch formation while keeping the overall mechanism compact.
2Adaptability or versatility
If traditional actuating mechanisms are used, then needle control is provided, but the number of needle movements and yarn feeds is limited
Solution Approach 1:
The cam is designed with multiple paths (first path for drop stitches, second path for tuck stitches) that can selectively engage with needle butts. The same cam structure serves multiple functions by providing different path options, enabling various needle movements and yarn feeds without requiring separate actuating mechanisms for each stitch type.
Solution Approach 2:
The selector can dynamically switch between engaging the first cam path and the second cam path based on the desired stitch type. This dynamic reconfiguration allows the same physical mechanism to provide multiple needle movements and accommodate different yarn feeds, increasing versatility without proportionally increasing device complexity.
3Ease of operation
If extensive actuating mechanisms are used for tuck and drop stitches, then stitch formation is achieved, but the machine becomes less suitable for alternating oscillatory motion
Solution Approach 1:
Instead of moving the cam radially relative to the needle cylinder as in traditional designs, the patent inverts the approach by positioning the cam axially above the needle cylinder and allowing the needle cylinder to rotate beneath it. This inversion simplifies the mechanism for alternating oscillatory motion, as the cam remains stationary while the needles are actuated through their axial grooves during rotation in either direction.
4Length of stationary object
If the machine diameter is reduced, then compactness is achieved, but the space for actuating means is insufficient
Solution Approach 1:
The actuating mechanism utilizes the axial dimension above the needle cylinder rather than requiring radial space. The cam is positioned in the axial direction and actuates needles through axial grooves, effectively using the vertical space above the needle cylinder. This allows compact machine diameter while providing sufficient space for all necessary actuating components.
Data Source
Figure 1
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Figure 2b
AI summary
A circular knitting machine comprises a needle-holding cylinder (2) having a plurality of longitudinal grooves (4) housing a plurality of needles (3), at least one yarn feed (110) operatively associated to the needles (3), actuating cams (C) arranged around the needle-holding cylinder (2) and movable with respect to the needle- holding cylinder (2) around the central axis (X-X), a drive chain (5) for each needle (3) operatively placed between the respective needle (3) and the actuating cams (C). The drive chain (5) comprises: a sub-needle (6), a selector (9) having a respective butt (37) which can be engaged with respective selector paths, a selecting device (200) acting under control upon the selector (9), a punch (7) equipped with a respective butt (25) which can be engaged with respective punch paths. Taking as reference the drive chain (5) rotating with respect to the actuating cams (C) around the central axis (X-X) in a sense of rotation (CW; CCW), the punch paths comprise a tuck stitch ascent (101) and a drop stitch ascent (102) for each yarn feed (110). An inlet of the drop stitch ascent (102) circumferentially precedes an inlet of the tuck stitch ascent (101). The selector paths comprise a single track (124) defining a first ascent (129) and a second ascent (100) placed in succession one after the other for each yarn feed (110). The first ascent (129) circumferentially precedes the second ascent (100) and is operatively associated to the drop stitch ascent (102) and the second ascent (100) is operatively associated to the tuck stitch ascent (101).