Elongated Needle Holes for High-Density Needling Tables
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Solution Overview
Problem
Existing needle machines with elliptical motion suffer from limited hole density due to the need for large circular holes, which compromises the consolidation quality and strength of the support table.
Innovation Solution
Designing a support table with holes that have elongated upper and lower openings, shaped as figure-8 or semi-circular arcs, allowing for closer hole placement without reducing the table's strength, by machining the holes with inclined sidewalls and specific angles to optimize the passage of needles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If circular holes with large diameter are used to allow elliptical needle motion, then needles can pass through freely, but hole density is limited and table strength is reduced
Solution Approach 1:
The patent changes the geometric parameters of the holes from circular to elongated shapes with specific dimensional ratios. The holes have a major axis parallel to the machine direction (MD) that is larger than the minor axis, allowing needles to pass through during elliptical motion while maintaining smaller overall hole area. This parameter optimization enables higher hole density without compromising needle passage capability.
Solution Approach 2:
The patent introduces directional dimensioning to the hole geometry, creating elongated holes with different dimensions in different directions. The major axis dimension (in MD direction) is optimized for needle passage, while the minor axis dimension is minimized to allow closer hole spacing. This dimensional differentiation resolves the contradiction between needing large holes for needle motion and small holes for high density.
2Ease of operation
If circular holes with large diameter are used, then needles can reciprocate freely, but the proportion of drilling increases making the table fragile
Solution Approach 1:
The patent optimizes the geometric parameters of holes to minimize material removal while ensuring needle reciprocation. By using elongated holes with controlled major and minor axis ratios, the drilling proportion is reduced compared to circular holes of equivalent passage capability. This preserves more table material, maintaining structural strength and rigidity.
Solution Approach 2:
The patent applies different geometric characteristics to different regions of the hole structure. The elongated shape concentrates the opening area in specific directions where needle passage is needed, while minimizing openings in other directions. This localized geometric optimization allows free needle reciprocation while preserving table material and strength in non-critical areas.
3Productivity
If high needle density is achieved with circular holes, then consolidation quality improves, but table strength is compromised due to high drilling proportion
Solution Approach 1:
The patent changes the hole geometry parameters to achieve optimal density-strength balance. The elongated hole shape with specific major-to-minor axis ratios allows higher hole density while removing less material overall. This enables increased needle density for better consolidation quality without proportionally increasing drilling volume that would weaken the table.
Solution Approach 2:
The patent uses directional dimensioning to optimize hole placement and size. By making holes elongated in the MD direction with controlled minor axis dimensions, the patent achieves high hole density in the transverse direction while maintaining adequate passage area in the MD direction. This dimensional strategy enables high needle density for quality consolidation while preserving table strength.
Data Source
AI summary
Needle machine comprising at least one needle plate, from which projects an array of needles, means for imparting an elliptical, reciprocating motion to the needles and at least one support table drilled with an array of through holes, or which it is intended to pass in a direction MD, being supported on it, a fabric or web of fibres to be consolidated by needling, the each executing an elliptical, reciprocating motion in the respective through holes, each having an upper respective opening on the fabric support side, a lower respective opening on the opposite side and an inner sidewall extending between the two upper and lower openings, characterised in that each hole is machined so that there is a longitudinal section with a greater dimension MD in which the upper respective opening of the hole has a greater dimension in the direction MD and, in this longitudinal section of greater dimension MD, the inner sidewall of the hole is defined, at least in its upper region, by two left and right lines inclined to the vertical and converging downwards, the angles of inclination of the two lines to the vertical being of opposite sign and in particular each having an absolute value of between 2 and 30° respectively, in particular having the same absolute value.