Cam-Based Bistable Mechanism for Switching Apparatus
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Solution Overview
Problem
Conventional bistable mechanisms in switching apparatuses are complex, expensive, and difficult to assemble, with a large mechanical housing required for increased stroke length, limiting flexibility and stability in actuation.
Innovation Solution
A bistable mechanism using a cam system with a roller and cam profile that includes an arc-shaped convex portion forming a varying angle of 10°-45°, allowing for reduced housing diameter and simplified assembly, with the option of one or two cam followers and symmetrical or asymmetrical cam profiles to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a toggle device with rods and compression springs is used for the bistable mechanism, then the mechanism provides stable end positions, but the mechanism becomes complicated, expensive, and time-consuming to assemble
Solution Approach 1:
The patent extracts the spring elements from the traditional toggle mechanism and replaces them with a cam profile. The cam profile inherently provides the bistable functionality through its geometric shape, eliminating the need for separate springs and rods. This simplifies the mechanism while maintaining stability at end positions.
Solution Approach 2:
The patent uses a cam profile with curved surfaces instead of straight rods and separate spring components. The curved cam profile achieves the same bistable function with fewer parts and simpler assembly, directly addressing the complexity issue while maintaining reliability.
2Length of moving object
If the stroke length of the actuating unit is increased, then the switching apparatus can accommodate larger stroke requirements, but the diameter of the mechanical housing must be increased
Solution Approach 1:
The patent transitions from a linear rod-based toggle mechanism to a rotational cam mechanism. This dimensional change allows the stroke length to be achieved through rotational motion and cam profile geometry rather than increasing linear dimensions, thereby reducing the housing diameter requirement.
Solution Approach 2:
The cam profile uses curved geometry to achieve the required stroke length through rotational movement. This allows the actuating unit to achieve larger strokes without proportionally increasing the housing diameter, as the cam's curved surface converts rotational motion into the desired linear displacement.
3Ease of operation
If rods are moved from inclined position to radial middle position in a toggle device, then the actuating unit can switch between end positions, but the springs must be gradually compressed and released requiring significant force
Solution Approach 1:
The patent replaces the spring-compression mechanism with a cam profile that uses geometric shaping to provide the necessary forces. The cam profile's varying radius and angle create the required force characteristics during actuation, eliminating the need to compress and release springs, thereby reducing the force requirement.
Solution Approach 2:
The cam profile varies its geometric parameters (radius, angle) along the actuation path to optimize force characteristics. By carefully designing the cam profile parameters, the mechanism achieves smooth actuation with reduced force requirements compared to the uniform spring compression in traditional toggle devices.
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 cam-based bistable mechanism reduces assembly complexity, allows for optimized performance, and achieves stable end positions with reduced friction and force variability, enabling smaller housing size and adaptable actuation characteristics.
Implementation Method 1
each cam follower includes a roller arranged to roll on the cam means
Data Source
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AI summary
The invention relates to a switching apparatus for closing and/or opening an electric circuit. It has an actuating unit (3, 5, 22) and a bistable mechanism (6). The actuating unit (3, 5, 22) is linearly movable between a first end position in which the switching apparatus is in a closed state and a second end position in which the switching apparatus is in an open state. The linear movement defines an axis. The bistable mechanism is arranged to ensure that the actuating unit (3, 5, 22) is held in either of the end positions. According to the invention, the bistable mechanism includes a cam means (7a, 7b) mechanically connected to the actuating unit (3, 5, 22) and at least one cam follower (8). The invention also relates to a use of the invented apparatus.