Position Switch Control Shaft Cam Mechanism State Retention
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Solution Overview
Problem
Existing position switches automatically return to their initial state when the external action causing a contact state change is lost, leading to unintended modifications in the contact state and angular position of the lever.
Innovation Solution
A position switch design that incorporates a control shaft with a first cam and a second cam integral in rotation, along with a cam follower and guide, which allows the switch to immobilize the control shaft and lever in extreme positions, memorizing the contact state and angular position even after the external action is removed, using a spring-loaded guide to block the rotation and maintain the positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotary lever automatically returns to its initial rest position when external action is lost, then the switch can reset itself, but the contact state and angular position cannot be memorized
Solution Approach 1:
The control shaft is segmented into multiple functional zones: a first cam portion for actuating the pusher and contacts, and a second cam portion for engaging the cam follower to immobilize the shaft. This segmentation allows the single control shaft to perform multiple functions - both actuation and memory retention - without requiring separate components for each function.
Solution Approach 2:
The control shaft serves multiple functions: it acts as the primary actuation mechanism through the first cam, serves as the memory element through the second cam and cam follower engagement, and provides the structural framework for the entire switching mechanism. This multi-functionality eliminates the need for separate memory components.
2Reliability
If the control shaft is immobilized in extreme positions, then the contact state is memorized, but the shaft cannot return automatically
Solution Approach 1:
The cam follower engagement is designed to be dynamic rather than permanent. The cam geometry allows the follower to engage with the second cam at extreme positions to immobilize the shaft, but the engagement can be disengaged by applying external torque in the opposite direction. This enables the system to switch between locked (memory) and unlocked (returnable) states as needed.
Solution Approach 2:
The cam follower is pre-positioned to engage with the second cam portion before the shaft reaches its extreme position, creating a blocking effect that prevents automatic return. This preliminary engagement ensures that once the shaft reaches the extreme position, it is immediately locked in place, maintaining the contact state without requiring additional locking mechanisms.
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
The solution effectively maintains the contact state and angular position of the lever, preventing unintended changes when the external action is absent, ensuring stable operation and memory of the switch's state.
Implementation Method 1
a spring-loaded guide to block the rotation and maintain the positions
Implementation Method 2
a guide operable in translation along an axis parallel to the translation axis of the pusher and applied against the second cam with the aid of a spring
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The switch has a body (1) containing a pusher (30) moving between positions along a translation axis (X). A switch assembly (31) controls an electric circuit, and is actuated by the pusher. A control shaft (21) is actuated to rotate between angular positions along a rotation axis (R) of a rotative lever (20) perpendicular to the translation axis, where the shaft cooperates with the pusher for moving between the angular positions. A cam (23) is rotatively connected to the control shaft. A blocking unit cooperates with the cam for immobilizing the control shaft in each of the angular positions.