Pivot Actuator Switching Cam With Involute Stop Surface
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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 contact surface design that follows a circle perpendicular to the drive axis, allowing for increased adjustment angles up to 25° to 30° or more, and includes a switching cam with a second stop surface for precise positioning, along with features like teething for precise movement and optional pistons for force compensation.
Engineering Contradictions & Design Principles
Engineering 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 damage the contact screws and the adjustment angle is limited
Solution Approach 1:
The contact surface is designed as an involute curve instead of a flat surface. This curved geometry ensures that the contact force always acts perpendicular to the contact surface, preventing damaging lateral forces on the contact screw while enabling a larger adjustment angle range of 25-30 degrees or more.
Solution Approach 2:
The contact surface geometry is changed from flat to involute shape, and the contact force direction is changed from arbitrary angle to always perpendicular to the contact surface. This parameter change in the contact mechanism allows both increased adjustment angle and protected contact screws.
2Adaptability or versatility
If the contact point position varies with adjustment, then the actuation angle is limited, but if the contact point remains fixed, then the adjustment angle can be increased
Solution Approach 1:
The involute contact surface geometry is specifically designed so that as the stop element moves along the adjustment axis, the contact point remains fixed at the same location on the contact surface. The curved shape compensates for the positional change, maintaining the contact point while enabling larger adjustment angles.
Solution Approach 2:
The involute contact surface is pre-designed with specific geometry that automatically maintains the contact point position fixed during adjustment. This preliminary geometric configuration ensures that no additional control mechanisms are needed to maintain the contact point while achieving increased adjustment angle.
3Adaptability or versatility
If stop screws are used for adjustment, then adjustment is possible, but the end surfaces of stop screws can be damaged by impact
Solution Approach 1:
The involute contact surface replaces the flat end surface of traditional stop screws. This curved surface distributes the impact force along the tangent direction, preventing concentration of stress at a single point and eliminating damage to the adjustment mechanism.
Solution Approach 2:
The impact force that would normally damage flat contact surfaces is converted into a beneficial perpendicular force against the involute surface. The curved geometry transforms the potentially harmful lateral impact into a useful normal force that maintains contact without damage.
Data Source
AI summary
A pivot actuator includes a housing, a drive shaft rotatably coupled to the housing, a piston within the housing and configured to engage the drive shaft so that movement of the piston along a longitudinal axis of the housing causes the drive shaft to pivot in a first direction about a drive axis within a first pivot angle to a first end position, a first stop element configured to adjustably select the first end position, and a switching cam configured to be coupled to and pivot with the drive shaft about the drive axis. The switching cam includes a first disc having a first stop surface configured to contact the first stop element to limit rotation of the drive shaft in the first direction about the drive axis to the first end position, wherein the first stop surface includes a first convex stop surface.