Rotary Switch Indexing via Tangential Blocking
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Solution Overview
Problem
Existing rotary switch indexing systems require strong and bulky components due to axial spring action, leading to friction, wear, and increased volume, while also being costly and delicate when reduced in size.
Innovation Solution
The indexing system employs tangentially arranged indexing members with resilient elements, allowing for reduced transverse strength and construction height, using radial displacement to block or unblock rotation, and incorporating polymeric materials to prevent creep, with further rigid indexing means to absorb rotational momentum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axial spring action is used in indexing systems, then the mechanism can provide robust locking, but the housing must be strong and bulky, increasing volume and weight
Solution Approach 1:
The patent transitions from axial spring action to tangential/azimuthal indexing member arrangement. The indexing members are positioned tangentially to the rotation axis, allowing the blocking force to extend substantially in the direction of the indexing member rather than axially. This dimensional change enables a more compact housing design while maintaining reliable locking.
Solution Approach 2:
The patent changes the directional parameter of the blocking force from axial to tangential. By arranging indexing members tangentially and having them displace radially to block rotation, the force direction aligns with the indexing member orientation. This parameter change allows reduced housing strength requirements and smaller volume.
2Manufacturing precision
If axial spring action is used to urge parts together, then tight axial design tolerances are obviated, but all forces on the housing are in axial direction requiring a strong housing
Solution Approach 1:
The patent shifts the force direction from axial to tangential by repositioning the indexing members. The spring now acts tangentially to urge indexing members into engagement with housing protrusions, rather than axially. This dimensional change distributes forces in different directions, reducing the requirement for strong axial housing structure.
3Reliability
If the rotor is pressed against the cap during rotation, then axial spring action is maintained, but friction increases causing wear and loss of reliability
Solution Approach 1:
The patent changes the engagement direction from axial pressing to tangential blocking. Indexing members displace radially to block rotation by engaging housing protrusions tangentially, rather than being pressed axially against the housing. This reduces sliding friction and wear while maintaining reliable indexing action.
Solution Approach 2:
The patent replaces the axial spring-pressing mechanism with a tangential blocking mechanism. Instead of continuous axial pressure causing friction, the system uses radial displacement of indexing members to create intermittent tangential blocking engagement. This substitution reduces harmful friction and wear.
4Strength
If radial indexing members are used to block rotation, then transverse strength requirements are reduced, but construction height and axial tolerances must be controlled
Solution Approach 1:
The patent positions indexing members tangentially rather than radially, and has them displace radially to block rotation. This arrangement allows the blocking force to extend in the direction of the indexing member (tangential direction), reducing requirements for transverse strength while the radial displacement mechanism controls construction height.
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 reduces the need for strong housing components, minimizes wear, and allows for a more compact and reliable indexing system that can handle heavy loads with improved control over rotation, while maintaining accurate positioning.
Implementation Method 1
The first indexing member may comprise a resilient element. Thus a restoring force towards a predetermined position may be provided
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An indexing system (1) for a rotary switch, comprises a housing (3; 13), a driving part (9) and a driven part (5), both being coupled to the housing for rotation with respect to the housing and with respect to each other about an axis of rotation (A). The housing and the driven part comprise cooperating first and second indexing means (119A, 119B; 33, 35) defining one or more relative angular positions. The indexing means comprise at least one first indexing member extending generally tangentially and/or azimuthally with respect to the axis of rotation and being at least partly reversibly movable between a first and a second radial position. In the first radial position the indexing means cooperate to block relative rotation of the housing and the driven part about the axis of rotation and in the second radial position the indexing means allow relative rotation of the housing and the driven part about the axis of rotation.