Turn Signal Stalk Magnetic Holding for Automatic Neutral Return
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Solution Overview
Problem
Conventional turn signal devices in motor vehicles require manual steering wheel movement to cancel turn signals, which can be cumbersome and inefficient, especially in situations where the driver needs to focus on other aspects of driving or vehicle operations.
Innovation Solution
The implementation of a cancellation device that includes a lever, detent pawl, centering spring, and magnets or motors to automatically return the turn signal stalk to its original position after activation, eliminating the need for manual steering wheel movement to cancel the signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual steering wheel movement is used to cancel turn signals, then the turn signal can be canceled, but the driver's attention is diverted from other driving tasks
Solution Approach 1:
The turn signal stalk is designed to automatically return to its neutral position through self-service mechanisms. A centering spring provides continuous bias toward the neutral position, and a detent mechanism with cam surfaces automatically engages to lock the stalk in place or allow it to return, eliminating the need for manual intervention to cancel the signal.
Solution Approach 2:
The patent replaces the purely mechanical manual return system with a hybrid system incorporating magnetic fields. Magnets are positioned to interact with ferromagnetic materials on the stalk, providing additional holding force in the activated position and assisting the centering spring in returning the stalk to neutral, thereby reducing the mechanical effort required from the driver.
2Device complexity
If the stalk is held in position by friction alone, then the structure is simple, but the holding force is insufficient and the stalk may drift
Solution Approach 1:
The detent mechanism is pre-configured with cam surfaces and detent balls positioned to engage at specific points along the stalk's travel path. The centering spring is pre-loaded to provide continuous bias toward the neutral position. These preliminary arrangements ensure that when the stalk reaches the neutral position, the detent mechanism automatically engages to lock it firmly in place, preventing drift without requiring complex active control systems.
Solution Approach 2:
The patent employs a composite approach combining multiple materials and mechanisms: ferromagnetic materials are integrated into the stalk to interact with magnets, a spring material provides elastic restoring force, and friction surfaces are engineered with specific coefficients to work in conjunction with the detent mechanism. This multi-material composite system achieves reliable position holding through the synergistic effect of magnetic attraction, spring force, and controlled friction.
3Speed
If a strong spring is used to return the lever, then the return speed is fast, but the force required to initially move the lever increases
Solution Approach 1:
The detent mechanism with cam surfaces acts as a mechanical counterweight system. The cam surfaces are shaped to provide mechanical advantage, allowing the detent ball to ride up the cam profile during initial movement (reducing the effective spring force the driver must overcome) and then lock into a valley position that holds the stalk firmly. The centering spring's force is thus modulated by the cam geometry rather than requiring the driver to directly overcome the full spring force.
Solution Approach 2:
The spring force is made dynamic through the detent mechanism's movement along the cam profile. During activation, the detent rides up the cam, temporarily reducing the effective restraining force. During return, the cam profile guides the detent to engage at the optimal point, maximizing the spring's return speed. This dynamic interaction between the detent, cam, and spring allows the system to provide both easy activation and fast return without requiring excessive force in either direction.
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 solution provides a hands-free operation for canceling turn signals, enhancing driver convenience and safety by allowing the driver to focus on other aspects of driving while the turn signal automatically returns to its neutral position.
Implementation Method 1
a magnet configured to generate a force to hold the lever in the second, non-neutral position
Implementation Method 2
a centering spring configured to bias the lever back to the first, neutral position
Implementation Method 3
a detent spring configured to bias the detent pawl
Data Source
AI summary
A cancellation device for an automotive feature on a vehicle includes a lever configured to be manually moved relative to the vehicle from a first, neutral position to a second, non-neutral position to actuate the automotive feature. The cancellation device also includes a detent pawl coupled to the lever such that the detent pawl moves with the lever, a detent spring configured to bias the detent pawl, a centering spring configured to bias the lever back to the first, neutral position, and a magnet configured to generate a force to hold the lever in the second, non-neutral position.