Pivot Actuator Involute Stop Geometry for Wider Angle Adjustment

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Solution Overview

Problem

Existing pivot actuators have limited adjustment angles due to the design of their contact surfaces, which can lead to damage and inefficiencies in positioning.

Innovation Solution

The pivot actuator incorporates an involute design transverse to the drive axis, allowing for a larger adjustment angle and precise positioning through a stop element adjustable along an orthogonal adjustment axis, with a switching cam that ensures consistent contact point impact and includes features like teething for precise movement and optional spring elements for fail-safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flat contact surfaces are used at different angles relative to the drive axis, then adjustment is possible, but the contact surfaces can impact end surfaces and cause damage to contact screws

Engineering Contradiction:
Improveadjustment capabilityVSAvoiddamage risk to contact screws
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces flat contact surfaces with an involute curve profile for the stop surface. This curved geometry ensures that the contact force between the stop element and switching cam always acts perpendicular to the drive axis, preventing damaging impact forces while maintaining full adjustment capability through threading the stop element along the adjustment axis.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If stop screws are used for adjustment, then end positions are adjustable, but the adjustment angle is limited by the size of the end surface contact area

Engineering Contradiction:
Improveend position adjustabilityVSAvoidadjustment angle range
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent transitions from adjusting stop screws along the drive axis to threading stop elements along a transverse adjustment axis. The involute stop surface converts this transverse movement into precise angular positioning, enabling adjustment angles of 25-30 degrees or more by utilizing radial space rather than being constrained by end surface contact area.

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

3Ease of operation

If the contact point position varies with adjustment, then stopping is possible, but the actuation angle is limited

Engineering Contradiction:
Improvestopping functionVSAvoidactuation angle range
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent employs an involute curve profile for the stop surface where the radius and contact point position vary systematically with the angular position. This geometric parameter change ensures that the contact force remains perpendicular to the drive axis throughout the adjustment range, enabling actuation angles of 25-30 degrees or more while maintaining reliable stopping function.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4308820B1Pivot actuator
Publication Date: 2025.08.20 BAR PNEUMATISCHE STEUERUNGSSYSTEME GMBH
  • EP4308820B1 patent drawingFigure 1~2b
  • EP4308820B1 patent drawingFigure 3a~3b
  • EP4308820B1 patent drawingFigure 4a~4b

AI summary

A pivot actuator (1), comprising: a housing (2); a piston (3) that is supported in the housing (2) and displaceable along a longitudinal axis (7) of the housing; a drive shaft (4) that protrudes from the housing (2) wherein the piston (3) engages the drive shaft (4) by form locking so that the drive shaft (4) is pivoted about a drive axis (8) by a pivot angle (10) to an end position through a displacement of the piston; and a switching cam (11, 26) that is fixed torque proof at the drive shaft (4) and configured to contact a stop element (5) at the housing (2) with a convex stop surface (18) at the switch element, wherein the end position is adjustable by an adjustment angle (25) about the drive axis (8) by displacing the stop element (5) along an adjustment axis (20) transversal to the drive axis (8), characterized in that the stop surface (18) follows an involute (22) of a circle (23) about the drive axis (8) wherein the involute is arranged in a direction transversal to the drive axis (8) so that the circle (23) is tangential to the adjustment axis (20).