Shift Lever Park Lock Using Solenoid and Cam Interlock
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automatic park locks for off-road or recreational utility vehicles are often complex, costly, and difficult to operate, lacking a simple and efficient solution for locking the operator shift lever in the park position.
Innovation Solution
An automatic park lock system featuring a pivotable operator shift lever with a cam surface and a spring-biased shift interlock solenoid, controlled by an electronic controller that energizes the solenoid based on ignition, brake pedal depression, and engine speed to lock or unlock the lever, allowing seamless shifting between positions without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing automatic park locks are implemented for off-road or recreational utility vehicles, then the shift lever can be locked in park position, but the system becomes complex, costly, and difficult to operate
Solution Approach 1:
The patent extracts the essential locking function from complex existing systems and implements it using only three basic components: a solenoid, a plunger, and a cam surface. This removes unnecessary complexity while maintaining the core park lock functionality, directly resolving the contradiction between reliability and device complexity
Solution Approach 2:
The system uses the vehicle's existing electrical system and operational conditions (ignition state, brake pedal position, engine speed) to automatically control the park lock without requiring separate control mechanisms. The plunger automatically engages or disengages based on these conditions, making the system self-regulating and reducing overall complexity
2Reliability
If existing automatic park locks are implemented, then the shift lever can be locked in park position, but the system becomes costly and difficult to operate
Solution Approach 1:
The park lock system automatically responds to the vehicle's operational state without requiring manual intervention. When the ignition is on, brake is depressed, and engine speed is at or below idle, the controller automatically de-energizes the solenoid to allow shifting. This self-service operation eliminates the need for separate control switches or manual procedures, making the system easy to operate while maintaining reliability
Solution Approach 2:
The patent combines the park lock control function with the existing vehicle operational parameters (ignition circuit, brake pedal switch, engine speed sensor). By merging these existing systems, the patent eliminates the need for separate control mechanisms, reducing cost and simplifying operation while maintaining reliable locking functionality
3Reliability
If the plunger remains extended to lock the shift lever, then the park position is secured, but wear and friction increase on the plunger and cam surface
Solution Approach 1:
The plunger alternates between extended (locked) and retracted (unlocked) positions based on periodic operational conditions. The system de-energizes the solenoid periodically when shifting is required, allowing the plunger to retract and roll on the cam surface rather than remain constantly engaged. This periodic action reduces continuous friction and wear while maintaining park position security when needed
Solution Approach 2:
The patent replaces a purely mechanical spring-biased plunger system with an electromechanical system using a solenoid. This allows precise control of plunger position based on electrical signals from the controller, enabling the plunger to retract when conditions warrant shifting. This substitution reduces unnecessary mechanical contact and wear compared to a continuously engaged mechanical system
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 system provides a cost-effective, easy-to-operate solution that reduces wear and friction, ensuring the shift lever remains locked in park when conditions are met, while allowing smooth transitions between gears when conditions are satisfied, enhancing operational efficiency and reducing battery consumption.
Implementation Method 1
A shift interlock solenoid has a plunger that is spring biased to an extended position into the groove to lock the operator shift lever in the park position
Implementation Method 2
An electronic controller energizes the shift interlock solenoid to retract the plunger from the groove if the controller receives a plurality of signals indicating the ignition key is on, the brake pedal is depressed, and the engine is at or below idle speed
Implementation Method 3
The retracted plunger contacts the sloped cam surface between the first end and the second end
Data Source
AI summary
An automatic park lock for an off road or recreational utility vehicle includes a shift interlock solenoid with a spring biased plunger engaging and locking an operator shift lever in the park position. A cam surface on the operator shift lever slopes between a first end and a second end, and has a groove to lock the plunger to the park position. A controller energizes the shift interlock solenoid to retract the plunger when a plurality of operating parameters are satisfied.