Turn Signal Lever Return Mechanism for Short Switching Angles
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Solution Overview
Problem
Existing turn signal reset systems are limited by the requirement for a sufficiently large switching angle, which makes them unsuitable for short switching distances, and they lack overload protection during reset.
Innovation Solution
A mechanical lever reset system where the trigger cam is connected to a rotatably mounted trigger ring on a bearing ring coupled to the steering column, using lever ratios and a spring element to operate without an inclined plane, allowing for non-parallel lever rotation axes and incorporating a protective mechanism to prevent damage from excessive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an inclined plane mechanism is used for lever return, then the system can achieve linear reset motion, but the switching angle cannot be made arbitrarily small requiring a sufficiently large switching angle
Solution Approach 1:
The patent replaces the traditional inclined plane mechanism with a lever ratio system. Instead of using an inclined plane that requires large switching angles, the invention employs a lever arm (Hebelarm) that rotates about an axis, utilizing lever mechanics to achieve the reset function with much smaller switching angles. The lever arm translates small angular movements into sufficient reset motion through mechanical advantage.
2Ease of manufacture
If the lever pivot axis is aligned parallel to the steering column, then the system follows conventional design, but it cannot compensate for height offset between lever pivot point and release cam position
Solution Approach 1:
The patent introduces a non-parallel arrangement of the lever pivot axis relative to the steering column axis. By orienting the lever pivot axis at an angle rather than parallel to the column, the system creates a three-dimensional geometric relationship that automatically compensates for height offsets between the lever pivot point and the release cam position. This angular orientation allows the lever mechanism to accommodate vertical misalignments through its rotational geometry.
3Ease of operation
If locking pawls are held by return spring in basic position, then they can be deflected in one direction, but overload protection during return while shift lever is held is not provided
Solution Approach 1:
The patent incorporates an overload protection mechanism that prevents damage before it occurs. The system includes a protective feature that limits the maximum force transmitted to the locking pawls during reset. If excessive force is applied or the shift lever is held in position during return, the overload protection mechanism engages to prevent damage to the locking pawls or other components, ensuring reliable operation under abnormal conditions.
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
Enables reliable operation at short switching paths and compensates for height offsets between lever pivot points and release cam positions, providing effective overload protection and preventing damage during reset.
Implementation Method 1
the two locking pawls are each held in a basic position by a return spring, from which they can only be deflected in one direction of rotation upon deflection of the return spring
Implementation Method 2
the release cam is connected to a release ring which is rotatably mounted on a bearing ring coupled to the steering column against the force of a spring element
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The invention relates to a mechanical lever-returning system for the switching lever of a turn signal switch in a motor vehicle, comprising a joint plate (3), which is coupled to the switching lever and which bears two latching pawls (4, 6), which each block a release cam (5, 5', 5a, 5b) in one direction and let the release cam pass in the opposite direction, the release cam being coupled to the steering column, wherein: the switching lever or a switching piece (1) connected to the switching lever is coupled to a rotatably mounted driver (2) by means of a rotary joint (20); the joint plate (3) is floatingly mounted on the driver (2); and the two latching pawls (4, 6) are held, by means of respective returning springs (7, 8), in an initial position, from which the latching pawls can be deflected only in one direction of rotation, the returning springs (7, 8) being deflected as a result.