Crank-Type Loom Drive Layout to Prevent Drive Shaft Bending

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Solution Overview

Problem

The conventional crank-type drive device for looms is prone to drive shaft bending, which causes deviations in the motion of the tension roll, leading to poor quality woven fabrics, especially in looms that weave wide or high-density fabrics.

Innovation Solution

The crank-type drive device is configured such that the presence range of the fixing mechanism of the crank hub and the presence range of the bearing overlap in the axis line direction of the drive shaft, reducing the run length and minimizing the likelihood of drive shaft bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the split clamping mechanism protrudes from the end face of the crank hub and the crank hub is attached to the drive shaft with the split clamping mechanism positioned closer to the tip end-side, then the crank hub can be securely fixed to the drive shaft, but the drive shaft becomes prone to bending due to increased run length

Engineering Contradiction:
Improvefixing strengthVSAvoiddrive shaft stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The invention inverts the conventional arrangement by positioning the split clamping mechanism on the attaching surface side of the crank hub rather than protruding from the opposite end face. This reversal places the fixing mechanism closer to the bearing support point, reducing the drive shaft run length from 300mm to 50mm and preventing bending while maintaining secure fixation

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If the drive shaft has a large run length to accommodate the crank hub and holder arrangement, then the components can be properly positioned, but the drive shaft bends under the force applied during operation

Engineering Contradiction:
Improvecomponent arrangementVSAvoiddrive shaft reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

By inverting the position of the split clamping mechanism to be located on the attaching surface side of the crank hub, the invention reduces the drive shaft run length from 300mm to 50mm. This inversion allows proper component positioning while preventing drive shaft bending under operational forces

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the spatial arrangement by positioning the split clamping mechanism in a different location along the drive shaft axis. The mechanism is now located within the presence range of the bearing in the axis line direction, creating a compact arrangement that reduces bending moment while maintaining functional integrity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If the crank hub is positioned closer to the tip end of the drive shaft to facilitate attachment, then assembly is simplified, but the drive shaft bending increases due to longer run length

Engineering Contradiction:
Improveassembly easeVSAvoidmotion precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention inverts the attachment approach by positioning the split clamping mechanism on the attaching surface side rather than the opposite end face. This allows secure fixation while reducing the drive shaft run length to 50mm, preventing bending and ensuring precise motion transmission

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP4001482B1Loom comprising a crank-type drive device
Publication Date: 2025.02.12 TSUDAKOMA KOGYO KK
  • EP4001482B1 patent drawingFigure 1
  • EP4001482B1 patent drawingFigure 2
  • EP4001482B1 patent drawingFigure 3

AI summary

A loom, comprising a crank-type drive device (20), comprising a crank hub (22) non-rotatably attached to a drive shaft (34), a holder (24) non-rotatably attached to the crank hub (22), an eccentric shaft (25) supported by the holder (24), and a connecting member (26) rotatably supported by the holder via the eccentric shaft (25) and a bearing (28) and connected to a drive target member (7) of a loom, wherein the holder (24) has an attached surface (24e) that is attached to the crank hub (22), is orthogonal to an axis line of the drive shaft (34) and is a surface facing toward a tip end of the drive shaft (34), and the crank hub (22) comprises a plate-shaped attaching part (22b) which the attached surface (24e) of the holder (24) is attached thereto and has an attaching surface (22d) in contact with the attached surface, and a fixing mechanism (22a1) for fixing the crank hub (22) to the drive shaft (34), the drive shaft being inserted and fitted in the fixing mechanism. The crank hub (22) is configured so that the fixing mechanism (22a1) is positioned on the attaching surface (22d)-side of the attaching part (22b) in a plate thickness direction.