Pull-down Device Pressure Lever Uniform Knitting Width
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Solution Overview
Problem
In flatbed knitting machines, the elongation of rollers in pull-down devices leads to uneven pressure distribution across the knitting width, affecting the knitting process and stitch quality due to reduced effectiveness and increased operational complexity.
Innovation Solution
A pull-down device with a pressure lever and pressure spring system that applies pressure uniformly across the middle part of the knitting width, utilizing an interlocking switch part and receiving member to maintain effective pressure distribution and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the knitting width is increased, then the production capacity is improved, but the rollers become elongated and bend in the middle part causing uneven pressure distribution
Solution Approach 1:
The pressure application system is segmented into multiple independent pressure springs distributed across the knitting width, with each spring acting on a specific zone. This segmentation allows each spring to independently maintain proper pressure without the cumulative bending effects that plague elongated single-roller systems, thereby maintaining uniform pressure distribution across increased knitting widths.
Solution Approach 2:
The patent applies local quality by providing pressure springs at specific locations (both sides and middle part) rather than uniform distribution. The pressure springs are strategically positioned to counteract the bending tendency of elongated rollers at critical zones, ensuring that each local area receives appropriate pressure independent of the overall roller deformation.
2Force
If pressure springs are extended to increase pressure in the middle part, then the pressure effectiveness is improved, but the spacing between cut end surfaces of cut flanges and lock members increases causing operational delay
Solution Approach 1:
The patent applies partial action by providing pressure springs only at critical locations (both sides and middle part) rather than along the entire length of the rollers. This selective pressure application maintains effectiveness where needed while minimizing the extension distance that would cause operational delay, achieving a balance between pressure effectiveness and response time.
3Ease of operation
If swing arms are used to open rollers on both sides, then the opening mechanism is improved, but the number of shafts and components increases making the device more complex
Solution Approach 1:
The patent merges the opening mechanism by using a single opening and closing shaft that controls both swing arms simultaneously. This consolidation reduces the number of independent shafts and components compared to having separate mechanisms for each roller, while still achieving the ease of operation needed for opening the rollers on both sides.
Solution Approach 2:
The opening and closing shaft serves multiple functions: it controls the swing arms for opening, coordinates the simultaneous movement of both rollers, and integrates the pressure spring activation. This multi-functionality reduces the overall component count while maintaining operational effectiveness.
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
Ensures consistent pressure application across the knitting width, preventing unevenness and maintaining efficient operation even with elongated rollers, thus improving stitch quality and reducing operational lag.
Implementation Method 1
a pressure spring (8) which biases the pull-down member (3, 4) in the closing direction
Implementation Method 2
The pair of rollers are capable of opening to a direction in which their outer peripheries are opened, and of closing to a direction in which their outer peripheries are closed... driven to revolve in a direction in which to pull-down the knitted fabric while sandwiching the knitted fabric between their closed outer peripheries
Data Source
Figure 1
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AI summary
There is provided a pull-down device for fabric that prevents unevenness of pressures on a middle part surfaces in a knitting width direction such that the application of the pressure to the middle part does not affect the operation of opening pull-down members. The pull-down device for fabric 1 includes a pressure lever 5 on the middle part in the knitting width direction to apply pressures between main rollers 3, 4. Opening and closing mechanisms provided on both sides in the knitting width direction swing to open and close the main roller 4 with respect to the main roller 3. The opening and closing mechanisms on the both sides are interlocked to swing by an opening and closing shaft 6 extending in the knitting width direction. The pressure lever 5 is inserted into the opening and closing shaft 6 to swing on the opening and closing shaft 6 as a fulcrum point. A switch member 7 is interposed between the opening and closing shaft 6 and the pressure lever 5. An interlocking switch part 12 is formed between a hole 7c in the switch member 7 and a pin 5e on the pressure lever 5. Even when the main rollers 3, 4 are closed, the interlocking switch part 12 makes effective the application of pressures by a pressure spring 8 within a gap between the hole 7c and the pin 5e so that the application of the pressures does not affect the opening operation.