Sewing Looper Positioning via Conical Set Bolt and V-Groove
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Solution Overview
Problem
Existing sewing devices face challenges in accurately positioning the looper relative to the needle, leading to stitch skips and discontinuous stitches due to inadequate reproducibility of their relative position, especially during replacement of consumable parts.
Innovation Solution
A sewing device with a rotation shaft and set bolt system, where the looper is positioned axially using a conical set bolt and a V-shaped groove, and a mounting member that supports the rotation shaft, allowing precise adjustment and fixation of the looper's position relative to the rotation shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a set bolt is used to fix the looper position, then the looper can be secured to the rotation shaft, but the looper cannot be positioned in the axial direction with respect to rotation
Solution Approach 1:
The set bolt features a conical distal end that engages with a V-shaped groove on the rotation shaft. The conical shape allows the bolt to be inserted from the radial direction while automatically positioning the looper in the axial direction through the inclined surfaces of the V-groove, eliminating the need for separate axial positioning mechanisms
2Ease of repair
If the needle and looper are replaced periodically, then consumable parts can be renewed, but reproducibility of the relative position between the needle and looper cannot be achieved with high accuracy
Solution Approach 1:
The V-shaped groove with inclined surfaces acts as a self-positioning mechanism. When the conical set bolt is inserted into the through-screw hole and tightened, the inclined surfaces automatically guide the looper to the correct axial position relative to the rotation shaft, ensuring reproducible positioning without requiring complex adjustment procedures during replacement
3Device complexity
If the relative position between needle and looper is not maintained with high accuracy, then the sewing device can operate with simpler positioning, but stitch skip occurs and loops become detangled
Solution Approach 1:
The conical set bolt engaging with the V-shaped groove creates a precise mechanical interface that maintains the critical relative position between needle and looper. This simple yet effective geometric configuration ensures the looper remains accurately positioned to skim the thread without requiring complex positioning systems
Data Source
AI summary
There is provided a sewing device comprising a needle and a looper, the sewing device including a rotation shaft that rotates the looper, and a set bolt that has a conical distal end and positions the looper in an axial direction relative to the rotation shaft from a radial direction of the rotation shaft, in which the looper includes a through screw hole into which the set bolt is screwed, the rotation shaft includes a groove recessed from a peripheral surface of the rotation shaft, and the groove includes an inclined surface that the distal end of the set bolt contacts. In one aspect, in the sewing device, a cross section of the groove viewed in a direction along an axis of the rotation shaft has a V shape. As a result, a relative position between the needle and the looper can be positioned with significantly high accuracy.