Electrical Switch Spring Jam Prevention Guide
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Solution Overview
Problem
Existing electrical switches with tactile axial actuation can experience increased actuation force and uncontrolled force variations due to the risk of the last turn of the spring becoming wedged between the ramp and the base, affecting the mechanical characteristics and user feedback.
Innovation Solution
Incorporating a guide bore with axial ribs and a complementary axial groove, along with a cam profile that forms a cone section, ensures the last turn of the helical compression spring is properly supported, preventing jamming and optimizing tactile feedback during actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the last coil of the return spring interacts with the actuator ramp to create radial force and axial force, then tactile sensation is produced, but the last coil may become stuck between the ramp and the lower base causing increased actuation force and uncontrolled force variations
Solution Approach 1:
The patent introduces a groove in the actuator ramp and a protrusion on the lower base as intermediary guiding elements. These features act as mediators that constrain the last coil's movement path, preventing it from becoming stuck between the ramp and base while maintaining the necessary radial and axial forces for tactile feedback.
Solution Approach 2:
The patent modifies the geometric parameters of the spring-end interaction zone by creating a groove in the ramp and adding a protrusion on the base. This changes the spatial constraints and movement parameters of the last coil, ensuring controlled deformation and preventing jamming while preserving tactile characteristics.
2Ease of operation
If the last coil is pushed radially outwards by the combination of radial and axial forces, then tactile feedback is enhanced, but the actuation force becomes uncontrolled and varies significantly
Solution Approach 1:
The groove in the ramp and protrusion on the base serve as guiding intermediaries that control the radial outward movement of the last coil. This guidance ensures that the radial force is applied in a controlled manner, producing consistent tactile feedback while preventing uncontrolled force variations during actuation.
3Device complexity
If the last coil becomes stuck between the ramp and lower base, then actuation reliability decreases, but the structural simplicity is maintained
Solution Approach 1:
The patent adds minimal guiding features (a groove in the ramp and a protrusion on the base) that act as intermediaries to prevent the last coil from becoming stuck. These simple geometric modifications significantly improve reliability by ensuring controlled movement of the spring end without requiring complex additional mechanisms.
Solution Approach 2:
The patent segments the interaction zone between the ramp and base by creating a groove in the ramp and adding a protrusion on the base. This segmentation divides the movement space into controlled regions, guiding the last coil along a specific path and preventing it from becoming trapped, thereby improving reliability with minimal structural addition.
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 design enhances the reliability and consistency of the tactile feel and actuation force, reducing the risk of increased force requirements and uncontrolled variations, thereby improving user experience and switch performance.
Implementation Method 1
an elastic return member (28) in the form of a helical compression spring which is traversed axially by said section of the upper actuating rod
Implementation Method 2
an elastic return member (28) in the form of a helical compression spring
Implementation Method 3
which, during the actuating stroke of the upper actuating rod (1), cooperates with a cam profile (20) formed in said side wall which deforms it radially to produce an elastic resistance to the actuating of the upper actuating rod
Implementation Method 4
a cam profile (20) formed in said side wall which deforms it radially
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The present invention relates to an electrical switch (20) comprising a base (22), an actuating rod (24) having a side wall (94) guided in a bore (80) of the base (22), a return spring (28) for the rod (24) which moves relative to the base (22), and comprising a final elastic coil (122) which, during the actuating stroke of the rod (24), bears against a stop surface (84) of the base (22) and which cooperates with a ramp formed in the side wall (94) which deforms it radially, characterized in that the bore (80) has a series of axial ribs (52) projecting inside the bore (80), each of which slides into a complementary axial groove (116) formed in the side wall (94), and in that a facet (84) radial upper end of each axial rib (82) constitutes a portion of said fixed abutment surface (84).