Personal Care Handle Coupling for Secure Vibration Transfer
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Solution Overview
Problem
Existing personal care electrical appliances face challenges in providing a universally usable design that ensures simple and secure mounting of plug-on parts and efficient vibration transmission.
Innovation Solution
The design features a handle with a vibration unit containing an electric motor and eccentric element, a plug-like coupling structure with a mirror-inverted socket-like interface, incorporating rotation-preventing means and a beveled stop surface for enhanced contact and snap-fit connection, allowing for secure attachment and effective vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple coupling structure is used for attaching plug-on parts, then the device complexity is reduced and ease of manufacture is improved, but the reliability of attachment and vibration transmission deteriorates
Solution Approach 1:
The coupling structure is divided into multiple functional stages: a first stage with a beveled stop surface for axial positioning and force transmission, and a second stage with rotation-preventing means for angular constraint. This segmentation allows each stage to specialize in specific functions, achieving reliable attachment and vibration transmission without excessive overall complexity.
Solution Approach 2:
The coupling structure employs asymmetric geometric features including a beveled stop surface at an oblique angle to the longitudinal axis, and non-circular rotation-preventing means such as cam profiles or key-way geometries. These asymmetric features prevent incorrect assembly, ensure proper orientation, and enhance the mechanical interlock between handle and plug-on part, thereby improving reliability without significantly increasing complexity.
2Ease of manufacture
If the electric motor is positioned away from the interface region, then the ease of manufacture and assembly is improved, but the effectiveness of vibration transmission to the plug-on part deteriorates
Solution Approach 1:
The electric motor is positioned at an angular offset (beta angle of 3° to 20°) relative to the longitudinal axis of the handle, rather than being aligned directly with it. This angular displacement in a different dimensional orientation allows the motor to be located in the interface region for effective vibration transmission, while still accommodating ease of assembly through the angled configuration that naturally guides the assembly process.
3Reliability
If a multi-stage interface with rotation-preventing means is used, then the reliability of plug-on part attachment is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The coupling structure merges multiple functions into a compact multi-stage interface: axial positioning (first stage with beveled surface), rotational constraint (second stage with cam or key-way), and mechanical interlock. By combining these functions in a sequential, space-efficient manner, the design achieves high attachment reliability while controlling overall complexity through functional integration rather than separate distributed components.
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 configuration ensures a secure and efficient attachment of plug-on parts and effective vibration transmission, improving the usability and longevity of the appliance across various personal care applications.
Implementation Method 1
a vibration unit having an electric motor and an eccentric element is arranged in the handle
Implementation Method 2
the handle has a cam which cooperates with a mirror-inverted recess of the plug-on part in the manner of a snap-fit connection
Data Source
AI summary
An electrical appliance for personal care includes a handle with a longitudinal axis, and a plug-on part which can be attached to the handle, wherein a vibration unit having an electric motor and an eccentric element is arranged in the handle, wherein a plug-like coupling structure protrudes from the handle, which plug-like coupling structure forms an interface with a substantially mirror-inverted socket-like coupling structure of the plug-on part, wherein the interface has at least two stages with different circumferential geometry, wherein at least one of the stages has a rotation-preventing means between the handle and the plug-on part, and wherein a stop surface of the handle for the plug-on part extends obliquely with respect to the longitudinal axis of the handle.