On-vehicle lever switch screwless knob assembly
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Solution Overview
Problem
The existing on-vehicle lever switches require a lengthy assembly process due to the need for screwing operations to fix the cover over the opening that houses the lead wire, which increases the time required for assembly.
Innovation Solution
The on-vehicle lever switch design includes a knob that can be divided into two portions, coupled using an engagement and locking mechanism without the need for screws, allowing the lever body to be assembled quickly by locking the first knob portion with the second knob portion using a drive shaft and press-fitting projections and recesses, eliminating the requirement for screwing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cover is fixed to the lever main body with screws to secure the opening, then the structural stability and reliability are improved, but the assembly time and manufacturing complexity increase
Solution Approach 1:
The patent removes the cover component entirely from the conventional structure. Instead of fixing a cover with screws, the lead wire is directly housed in the opening of the lever main body, and the switch is mounted directly without requiring a cover closure. This extraction of the cover eliminates the screwing operation and reduces assembly steps while maintaining the functional requirements of housing the lead wire and supporting the switch.
Solution Approach 2:
The lever main body is divided into distinct functional sections: the opening for housing the lead wire, the mounting area for the switch, and the operational components. This segmentation allows each part to be assembled independently and directly, without requiring a separate cover component to enclose them, thereby simplifying the overall assembly process.
2Device complexity
If the knob is made as a single integrated piece, then the structural simplicity is maintained, but the assembly complexity and time increase due to screwing operations
Solution Approach 1:
The knob is divided into a first knob portion and a second knob portion that can be assembled separately. The first knob portion is coupled to the second knob portion through a coupling mechanism involving a coupling member that engages with coupling holes and positioning protrusions. This segmentation allows for easier manufacturing and assembly of the individual portions without requiring complex screwing operations, while still achieving a unified functional knob structure.
Solution Approach 2:
A coupling member acts as an intermediary element between the first and second knob portions. This coupling member includes engagement portions that fit into coupling holes and positioning protrusions, enabling the two knob portions to be connected securely without requiring screws. The intermediary coupling mechanism simplifies the assembly process while maintaining the structural integrity of the integrated knob.
3Strength
If the knob portions are coupled with screws, then the connection strength and reliability are improved, but the ease of manufacture and assembly are reduced
Solution Approach 1:
The screw fastening mechanism is completely removed from the coupling process of the knob portions. Instead of using screws to join the first and second knob portions, the patent employs a screwless coupling mechanism where coupling members engage with coupling holes and positioning protrusions. This extraction of the screw component maintains connection strength through precise geometric engagement while dramatically improving ease of manufacture and assembly.
Solution Approach 2:
The coupling mechanism is designed to be self-assembling without requiring external fastening tools or operations. The positioning protrusions and coupling holes are configured to automatically align and engage the first and second knob portions when brought together, allowing the components to self-secure without manual screwing operations. This self-service coupling mechanism maintains strong connections while simplifying the assembly process.
Data Source
AI summary
An on-vehicle lever switch includes a main body portion, a lever body, and a switch contact. The lever body includes a knob rockably held by the main body portion and protruding outward, a drive shaft extending in the direction along which the knob protrudes and being rotatably held in the knob, and a rotational operation portion fixed to the drive shaft. The switch contact is disposed at the main body portion, and carries out electrical connection by rocking or rotating of the lever body. The knob can be divided into two portions, a first knob portion and a second knob portion, along the extending direction. The first knob portion and the second knob portion are coupled to each other by a first member provided in the inner part of the first knob portion and a second member provided in the inner part of the second knob portion.