Actuator Piston Adjustable Stops for Precise Stroke Limiting

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Solution Overview

Problem

Existing actuator systems rely on mechanical hardstops for limiting physical movement, which are not easily adjustable and lack precision in regulating the physical limits of actuators, particularly in critical applications like primary flight control systems.

Innovation Solution

The actuator piston incorporates a screw connection between stop members, allowing for adjustable axial positioning through rotational movement, enabling precise regulation of the actuator's physical limits by varying the pitch of screw threads between stop members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fixed mechanical hardstops are used to limit actuator movement, then safety is ensured, but adjustability and precision are lost

Engineering Contradiction:
ImprovesafetyVSAvoidadjustability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transforms fixed hardstops into adjustable stops through a screw mechanism. The stop members can be rotated along the screw thread to change their axial positions, allowing dynamic adjustment of the actuator's movement limits while maintaining the safety function. This resolves the contradiction by making the previously static system dynamic and adjustable.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the positional parameter of the stop members by rotating them along the screw thread. By varying the axial position of the stop members through rotational movement, the system achieves adjustable precision limits while maintaining the safety function, thus resolving the contradiction between fixed safety and adjustable precision.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If adjustable stop mechanism is added, then precision and adaptability are improved, but device complexity increases

Engineering Contradiction:
ImproveprecisionVSAvoidcomplexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The screw mechanism serves multiple functions: it provides the adjustment mechanism, acts as a positioning system, and enables precise control of stop member positions. By making the screw serve multiple functions, the patent achieves precision adjustment without proportionally increasing complexity, as the same component performs multiple roles.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The stop members are positioned within the actuator housing, with the second stop member located at least partially within a cavity that extends radially between the fixed portion and the actuator piston. This nested arrangement compactly integrates the adjustment mechanism within the existing actuator structure, minimizing additional space and complexity while achieving precise adjustment capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If screw connection is used for adjustment, then ease of operation is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveease of adjustmentVSAvoidscrew thread precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The screw mechanism is designed to be self-adjusting through simple rotation. The operator only needs to rotate the stop member along the screw thread to achieve precise positioning, without requiring complex tools or procedures. The screw thread itself provides the precision guidance, making the system easy to operate while the manufacturing precision is concentrated in the screw thread fabrication rather than assembly.

Inventive Principle:
Principle #25Self-service

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 provides a compact, adjustable, and precise mechanism for regulating the actuator's movement, ensuring symmetrical and asymmetrical regulation options, enhancing safety and control in critical applications by allowing for customizable stop positions.

Implementation Method 1

The actuator may further comprise a nut rotatable about the axis. The nut may be connected to, or form part of, the first stop member such that rotation of the nut about the axis causes a corresponding rotation of the first stop member about the axis and, in turn, movement of the second stop member along the axis

Methodology Applied
Scientific EffectScrew thread mechanism: Screw

Data Source

PatentEP3550179B1Actuator piston with adjustable stops and method of adjusting the same
Publication Date: 2022.06.01 MICROTECHNICA SRL
  • EP3550179B1 patent drawingFigure 1
  • EP3550179B1 patent drawingFigure 2
  • EP3550179B1 patent drawingFigure 3A

AI summary

The disclosure provides an actuator comprising an actuator piston movable along an axis, a first stop member rotatable about the axis and configured to limit the movement of the actuator piston in a first direction along the axis, a second stop member movable along the axis and configured to limit the movement of the actuator piston in a second direction along the axis, wherein the first direction is opposite to the second direction. In accordance with the disclosure, a first screw connection is present between the first stop member and the second stop member such that rotation of the first stop member about the axis causes movement of the second stop member along the axis to vary the amount by which the actuator piston can move along the axis in use.