Rocking Drive Control for Backlash-Free Relaxation Chairs
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Solution Overview
Problem
Existing relaxation devices cause discomfort due to backlash and unstable load fluctuations during maximum rocking amplitude, leading to an uncomfortable experience for users.
Innovation Solution
The control means of the relaxation device adjusts motor rotation speed and direction to maintain a consistent load on components, preventing inversion of the load direction at maximum amplitude and stabilizing rocking speed by varying motor speed based on load levels, and temporarily stopping the motor to allow the body support to invert due to its weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the motor produces alternating normal and reverse rotation to rock the body supporting means, then the relaxation device can provide varying rocking amplitudes, but the load direction on transmission components inverts causing backlash and user discomfort
Solution Approach 1:
The patent applies dynamics by making the motor rotation direction static (single-direction) during maximum amplitude rocking instead of dynamically alternating directions. This eliminates the inversion of load direction on transmission components, preventing backlash and the associated uncomfortable sensation for the user while still achieving varying rocking amplitudes through speed control.
Solution Approach 2:
The patent changes the parameter of motor rotation direction from alternating (normal and reverse) to single-direction during maximum amplitude operation. This parameter change eliminates the load direction inversion on transmission components, resolving the technical contradiction between amplitude versatility and user comfort.
2Speed
If the motor rotation speed is increased to achieve maximum rocking amplitude, then the relaxing effect is enhanced, but the load on components increases causing instability and discomfort
Solution Approach 1:
The control means monitors the rocking amplitude and automatically adjusts motor rotation speed accordingly. When maximum amplitude is detected, the control means maintains single-direction rotation and optimizes speed to prevent excessive load, ensuring stable and comfortable operation without requiring manual intervention.
3Ease of operation
If the motor alternates rotation direction frequently to maintain moderate rocking amplitude, then user comfort is improved, but the load fluctuations on components increase causing instability
Solution Approach 1:
The patent applies dynamics by adapting motor rotation behavior to operating conditions: alternating rotation for moderate amplitudes and single-direction rotation for maximum amplitude. This dynamic adjustment optimizes both user comfort and load stability on transmission components across different operating ranges.
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 approach reduces user discomfort and enhances the relaxing effect by minimizing load fluctuations and maintaining stable rocking speed, providing a more comfortable and effective relaxation experience.
Implementation Method 1
a motor, which is capable of producing rotation in forward and reverse directions
Implementation Method 2
a speed reducer, which reduces the speed of the drive force generated by the motor
Implementation Method 3
a crank, which is connected to an output shaft of the speed reducer in an integrally rotatable manner, and a rod, which is pivotally connected to a distal end of the crank
Implementation Method 4
The speed reducer, crank, and rod transmit the drive force of the motor to the base. This rocks the body supporting means
Implementation Method 5
the control means starts to drive and invert rotation of the motor after the body supporting means start to invert rotation due to its own weight
Data Source
Figure 1
Figure 2(a)~3
Figure 4(a)~4(c)
AI summary
A swinging drive device (12) installed on a base (11) comprises a crank member (22a), a rod member (22b) and a link member (23) for converting both of the alternating forward and reverse rotations and the unidirectional rotation of a motor (20) into the swinging motion of a body support member (13). A controller (24) rotates the motor (20) in one direction when the body support member (13) is swung with the maximum amplitude.