Linear Actuator Leverage Assembly for Precise Nip Pressure

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Solution Overview

Problem

Existing roll-molding processes for viscous resins face challenges in applying controlled nip pressures without damaging roll surfaces, particularly in continuous touch fastener manufacturing, where hydraulic cylinders are used but require improvements in movement and loading of mold rolls.

Innovation Solution

A linear actuator leverage assembly that includes a structural base, rail member, lever arm, and drive cylinder, allowing the mold roll to move along a continuous motion path with increased leverage as it approaches a reaction surface, enabling precise control of nip pressure for molding resin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If hydraulic cylinders are used to force rolls together to create nip pressure, then substantial pressure can be applied for molding viscous resins, but the risk of damaging roll surfaces increases if pressure is applied without resin in the nip

Engineering Contradiction:
Improvenip pressureVSAvoidroll surface damage
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The system transitions from static hydraulic cylinder positioning to dynamic lever arm movement that automatically adjusts the mold roll position. The lever arm rotates about a fulcrum to move the mold roll into and out of the nip zone, enabling controlled application of nip pressure only when resin is present, thereby preventing roll surface damage while maintaining necessary molding pressure

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The lever arm acts as an intermediary mechanism between the linear actuator and the mold roll. It translates linear actuator motion into rotational movement about a fulcrum, providing mechanical advantage and precise control over the mold roll's position relative to the nip zone, ensuring pressure is applied only when appropriate

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a linear actuator directly moves the mold roll, then the structure is simple, but the leverage and precision of nip pressure control are insufficient

Engineering Contradiction:
Improveactuator structureVSAvoidnip pressure control
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The system employs dynamic lever arm rotation about a fulcrum instead of direct linear actuator-to-roll connection. This dynamic mechanism provides variable leverage throughout the motion range, enabling precise control of nip pressure while maintaining relative structural simplicity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The linear actuator motion is converted into rotational motion in a different dimension through the lever arm mechanism. This dimensional transformation provides mechanical advantage and enhanced control precision without significantly increasing structural complexity

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

3Productivity

If the mold roll is moved quickly into position, then productivity increases, but the control over nip pressure application becomes less precise

Engineering Contradiction:
Improveroll positioning speedVSAvoidnip pressure control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The lever arm rotation provides dynamic control where the mold roll can be quickly moved into position during the majority of the stroke, then precisely positioned at the nip zone as the lever arm approaches its final rotational position. The mechanical advantage increases near the endpoint, enabling precise pressure control without sacrificing overall positioning speed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses staged motion where the linear actuator operates in different phases: rapid positioning phase for most of the stroke, and precise control phase near the endpoint. This periodic action pattern enables both high productivity and precise nip pressure control

Inventive Principle:
Principle #19Periodic action

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

This solution allows for controlled and efficient application of nip pressure, effectively moving the mold roll into proximity with a reaction surface to form continuous or interrupted resin layers, enhancing the production of touch fastener products while minimizing roll surface damage.

Implementation Method 1

The first pivot is located generally between the second pivot and the bearing surface, such that the linear actuator is adapted to move the rail member with respect to the base over a linear stroke of the linear actuator that moves the second pivot along a continuous motion path... over which the lever arm pivots about the bearing surface as a fulcrum, increasing leverage applied by the actuator to the rail

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

the bearing surface of the lever arm includes an outer surface of a roller bearing

Methodology Applied
Scientific EffectRolling friction: Roller

Data Source

PatentEP3703925B1Linear actuator leverage
Publication Date: 2021.02.17 VELCRO IP HOLDINGS LLC
  • EP3703925B1 patent drawingFigure 1A
  • EP3703925B1 patent drawingFigure 1B~1C
  • EP3703925B1 patent drawingFigure 2~3

AI summary

A linear actuator leverage assembly (100) including a base (102) with a side surface (126) and a back surface (128) defining between them a corner (130), a rail member (104) coupled to the base (102), a lever arm (106) with a bearing surface (131), and a linear actuator (108). The lever arm (106) is pivotally connected to the rail member (104) at a first pivot (136) and to the linear actuator at a second pivot (134). The linear actuator (108) is configured to move the rail member (104) with respect to the base (102) over a linear stroke of the linear actuator (108) that moves the second pivot (134) of the lever arm (106) along a continuous motion path. The motion path includes a first path segment generally parallel to the side surface (126) and a second path segment, over which the lever arm (106) pivots about the bearing surface as a fulcrum, thereby increasing leverage applied by the actuator (108) to the rail (104).