Controllable Friction Mechanism for Rotary Input Tactile Feedback
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Solution Overview
Problem
Rotary inputs in electronic devices often lack a mechanical stop or limit, leading to a lack of tactile feedback for users, which can negatively impact the user experience.
Innovation Solution
A controllable friction mechanism is introduced, utilizing a spring bar member and a movable tension member coupled with a motor to apply adjustable frictional forces to the rotary input shaft, providing haptic feedback to the user.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If no friction mechanism is applied to the rotary input shaft, then the rotary input can rotate freely without resistance, but the user receives no tactile feedback during rotation
Solution Approach 1:
A spring bar member is introduced as an intermediary element between the rotary input shaft and the tension member. The spring bar applies frictional force to the shaft through its contact surface, providing tactile feedback while allowing the shaft to rotate freely. This intermediary mechanism resolves the contradiction by enabling feedback without requiring direct mechanical coupling or complex stopping mechanisms.
Solution Approach 2:
The patent replaces traditional mechanical stop or click mechanisms with a friction-based system. Instead of using discrete mechanical elements that physically block rotation, the spring bar creates continuous frictional resistance that provides tactile feedback. This substitution eliminates complex mechanical stops while achieving the desired user feedback through controlled friction.
2Adaptability or versatility
If a fixed friction force is applied to the rotary input shaft, then tactile feedback is provided, but the friction level cannot be adjusted for different operational states
Solution Approach 1:
The system transitions from static to dynamic friction control through the introduction of a movable tension member. The tension member can be positioned at different locations along the spring bar, dynamically adjusting the frictional force applied to the rotary shaft. This dynamic adjustment capability allows the system to adapt friction levels to different operational states while maintaining a relatively simple mechanical structure.
Solution Approach 2:
The friction level is controlled by changing the position parameter of the tension member along the spring bar. By moving the tension member to different positions, the effective contact point on the spring bar changes, which alters the frictional force transmitted to the rotary input shaft. This parameter-based control provides adjustable friction levels without requiring complex control mechanisms.
3Reliability
If high friction is applied to prevent accidental rotations, then stability is improved, but legitimate user rotations become difficult to initiate
Solution Approach 1:
The system uses variable friction parameters achieved through tension member positioning. By adjusting the tension member position, the friction level can be optimized to provide sufficient resistance against accidental rotations while maintaining ease of initiation for legitimate user input. The spring bar's elastic properties further modulate the friction characteristic, allowing smooth initiation while maintaining stability.
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 mechanism allows for variable and adjustable haptic feedback, enhancing the user experience by providing tactile resistance during rotation, reducing accidental rotations, and signaling events like reaching the end of a list or menu through controlled friction levels.
Implementation Method 1
the spring bar engages the shaft and applies haptic feedback in the form of a frictional force to the shaft
Data Source
AI summary
Apparatuses and methods for an electronic device to control the application of friction to a rotary input control with a shaft. In one example, the apparatus may include a spring bar member having a first surface and a second surface, the first surface positioned adjacent to the shaft; and a movable tension member positioned to engage the second surface of the spring bar; wherein as the tension member engages the spring bar, the spring bar engages the shaft and applies a frictional force to the shaft. In this manner, the apparatus can controllably apply a friction force of a desired amount to the rotary input control.