Spring-Energized Transfer Receiving Cam for Knitting Needles
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Solution Overview
Problem
In flatbed knitting machines, the cam device for transfer receiving needles experiences stress concentration and potential damage due to reduced hanging margins when the carriage speed increases, leading to unreliable guidance and protrusion of the rear butt over the cam face, especially at level differences in the cam surfaces.
Innovation Solution
A cam device with a chevron-shaped raising cam and transfer receiving cams, featuring a pair of cams with a spring-energized idle end that protrudes to maintain a sufficient hanging margin and guide the rear butt smoothly over level differences, including support elongated holes for swing displacement, ensuring reliable guidance and reduced stress on cam faces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the carriage speed is increased to improve productivity, then the knitting machine can produce more output per unit time, but the hanging margin of the rear butt over the cam face is reduced, leading to stress concentration and potential damage
Solution Approach 1:
The cam device is designed to advance the rear butt preliminarily before the main knitting action occurs. This preliminary advancement ensures that the rear butt is properly positioned on the cam face earlier in the cycle, increasing the hanging margin even at higher carriage speeds and preventing stress concentration
Solution Approach 2:
The cam device is segmented into multiple functional components: a raising cam for vertical motion, a transfer cam for horizontal motion, and an intermediate cam for coordinated motion. This segmentation allows each cam to be optimized independently, with the raising cam specifically designed to maintain adequate hanging margins during high-speed operation
2Device complexity
If the hanging margin is reduced at higher speeds, then the cam device can be more compact, but the rear butt may protrude over the cam face causing unreliable guidance and potential damage
Solution Approach 1:
The cam device employs dynamic timing where the raising cam and transfer cam are coordinated to advance the rear butt at optimal moments during the carriage cycle. This dynamic coordination ensures that the rear butt maintains proper engagement with the cam faces throughout the motion, preventing protrusion while maintaining compact dimensions
Solution Approach 2:
An intermediate cam is introduced as a mediator between the raising cam and transfer cam. This intermediate cam coordinates the motion timing, ensuring that the rear butt is advanced smoothly without protruding over the cam faces, thereby maintaining guidance reliability in a compact configuration
3Ease of manufacture
If the cam device uses a simple structure, then it is easier to manufacture, but it cannot provide sufficient guidance and force distribution at high speeds
Solution Approach 1:
The cam device is divided into separate, standardized cam components (raising cam, transfer cam, intermediate cam) that can be manufactured independently using conventional machining processes. Each cam has a simple geometric profile that is easy to manufacture, yet the coordinated arrangement of these simple components provides the complex motion control needed for reliable high-speed 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 solution ensures smooth passage of the rear butt over level differences, maintains a sufficient hanging margin, and prevents cam face damage by distributing the force effectively, allowing reliable guidance and operation even at increased carriage speeds.
Implementation Method 1
a spring mounted to each transfer receiving cam respectively, and energizing in such a manner that the idle end side of each transfer receiving cam is brought into the protruded state with respect to the bottom board
Implementation Method 2
having a base end and an idle end, the idle end side rises and sinks with respect to the bottom board by a swing displacement around a swing shaft parallel to the surface of the bottom board on the base end side
Data Source
Figure 1
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AI summary
Provided is a cam device for the transfer receiving needle in which a rear butt smoothly passes a level difference portion, and which secures sufficient hanging margin on the cam face after the rear butt passes and can perform a reliable guidance. When a stitch transfer is performed by a carriage running leftward, a rear butt 7 of a knitting needle that serves as a receiving needle moves as shown as a trajectory 7H. For the transfer receiving cam 46 on the left side, the front end of the upper end of the rear butt 7 is hanged to the slope 46d and the rear end of the rear butt 7 is guided by the cam face 42b of the front edge of the intermediate cam 42c. The advance of the rear butt 7 pressurizes the slope 46d in opposition to the energizing force of a compression spring 47, and the transfer receiving cam 46 has the idle end side sunken and the upper end of the rear butt 7 is brought in contact with the surface 46c of the transfer receiving cam 46. Because the surface 46c sinks, in the vicinity of the top of the intermediate cam 42c, the level difference of the pathway of the rear butt 7 can be reduced or cancelled. When the rear butt passes the vicinity of the top portion, the rear butt comes in contact with the cam face 42b in the protruded state, and a sufficiently large hanging margin is able to be secured.