Shift Lever Assembly Single Switch Park Signal Key Removal
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Solution Overview
Problem
Current shift lever assemblies for vehicles with automatic transmissions require multiple switches and a significant travel distance to actuate, increasing complexity and space requirements, while failing to meet safety regulations efficiently.
Innovation Solution
A single switch assembly is designed, where a rotatable shift lever engages a switch with a plunger and contacts to produce signals indicating the transmission is in park and authorizing key removal, reducing parts and space by utilizing a single switch and minimizing travel distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple switches are used to detect park position and authorize key removal, then the reliability of safety regulation compliance is improved, but the device complexity increases
Solution Approach 1:
The patent combines two separate switch functions into a single switch assembly. The first switch detects park position, while the second switch authorizes key removal. Both functions are integrated into one compact assembly with a single actuator that can sequentially engage both switches, thereby reducing device complexity while maintaining safety compliance.
Solution Approach 2:
The single switch assembly performs multiple functions: it detects park position, authorizes key removal, and provides sequential actuation for both functions. This multi-functional design eliminates the need for separate switches while ensuring both safety requirements are met through a unified mechanism.
2Reliability
If multiple switches are used independently, then each switch can be actuated reliably, but the space requirements increase
Solution Approach 1:
The patent merges two independent switch assemblies into a single integrated unit. Both switches are positioned within the same housing and share a common actuator mechanism, significantly reducing the space required while ensuring each switch can be reliably actuated in the proper sequence.
Solution Approach 2:
The switch assembly is designed with one switch nested within or adjacent to the other, sharing common structural elements and actuation mechanisms. This nested arrangement minimizes the overall footprint while maintaining independent functionality for both switches.
3Device complexity
If a single switch assembly is used, then the device complexity and space requirements are reduced, but the ability to provide sequenced signals may be compromised
Solution Approach 1:
The switch assembly is designed with ramps that guide the actuator in a specific sequence. The first ramp engages the first switch to detect park position, and only after this switch is actuated does the second ramp engage the second switch to authorize key removal. This preliminary positioning ensures proper signal sequencing is maintained.
Solution Approach 2:
The actuator dynamically engages different portions of the two switches during its travel path. The single actuator moves sequentially, first depressing the park position switch, then continuing to depress the key removal switch. This dynamic sequential engagement ensures both signals are provided in the correct order despite using a single switch assembly.
Data Source
AI summary
A shift lever assembly utilizing a single switch to produce a first signal indicating that a transmission of a vehicle is in a park position and a second signal to authorize removal of a key from an ignition of the vehicle is disclosed. The switch includes a casing supporting a plunger having a first park indication contact and a first key removal contact. The casing includes a second park indication contact and a second key removal contact. The first park indication contact engages the second park indication contact when the plunger is in a rest position and is disengaged from the second park indication contact when the plunger is in a depressed position. The first key removal contact is disengaged from the second key removal contact when the plunger is in the rest position and engages the second key removal contact when the plunger is in the depressed position.