Retrograde Time Display Cam Flank Mechanism
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Solution Overview
Problem
Retrograde display devices with steep cam flanks face issues during reverse time correction, leading to potential blocking or breakage, and existing solutions for bidirectional correction are complex and require additional components, making them prone to user error.
Innovation Solution
Incorporating second elastic means between the feeler and lever to allow relative movement, and using a stop to immobilize the lever during cam flank ascent, ensuring stable operation and accurate time display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a steep cam flank is used in a retrograde display device, then the indicator member can return instantly from position B to position A, but the mechanism is prone to blocking or breakage during reverse correction
Solution Approach 1:
The cam profile is designed with a dynamic transition: a steep flank for rapid return during normal operation, and a controlled ascent path for reverse correction. The feeler mechanism dynamically adapts by allowing the indicator to move backward along the ascent path rather than forcing instant return, preventing mechanical blocking while maintaining the steep flank's benefit during forward operation
Solution Approach 2:
The feeler acts as an intermediary between the cam and indicator member. During reverse correction, the feeler engages the cam flank at a controlled angle, mediating the interaction to prevent direct blocking. This intermediary mechanism allows smooth backward movement while maintaining engagement, resolving the contradiction between steep flank performance and reverse correction safety
2Adaptability or versatility
If a disengagement device is added to allow bidirectional correction, then reverse correction becomes possible, but the device complexity increases and user errors may occur
Solution Approach 1:
The cam profile serves multiple functions: it enables both forward operation with instant return via the steep flank and backward correction via the controlled ascent path. The feeler mechanism similarly performs dual functions by engaging different portions of the cam profile depending on correction direction. This multi-functionality eliminates the need for separate disengagement devices, reducing complexity while maintaining bidirectional capability
Solution Approach 2:
The mechanism automatically adapts to correction direction through its inherent geometry. During reverse correction, the cam's ascent path and feeler engagement naturally guide the indicator backward without requiring user activation of separate disengagement mechanisms. The system self-regulates based on the cam profile geometry, preventing user errors associated with complex disengagement devices
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 and simple backward correction of retrograde systems, minimizing the risk of mechanical damage and user errors, while maintaining accurate time indication.
Implementation Method 1
these second elastic means are of course separate from the first elastic means which are arranged to urge the lever so as to bring it into contact with the cam by means of the feeler
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A display device (100) for time information using an indicator element (1), comprising: • a cam (2) whose profile has a flank (23); • a lever (4) for driving the indicator element (1); • a feeler (3) for controlling the lever (4), bearing against the cam (2) under the action of first elastic means (6), adapted so that, when the flank (23) passes in a first direction of movement of the cam (2), it controls a movement of the lever (4) intended to drive the indicator element (1) in movement. The feeler (3) for controlling the lever (4) is adapted so that, when the flank (23) passes in a second direction of movement of the cam (2), it moves relative to the lever (4) against the return action of second elastic means (5), under the effect of an action force (F) exerted by the flank (23) of the cam (2) on the feeler (3).