Handle for Electric Toothbrush with Head-Mounted Motor
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Solution Overview
Problem
Existing electrically operated personal care implements, such as toothbrushes, face challenges in maintaining reliable vibration modes during use while ensuring good maneuverability, as the amplitude of vibrations is heavily dependent on the user's grip and the design of the handle can compromise on reachability and comfort.
Innovation Solution
A handle design for electrically operated personal care implements featuring a housing with a motor and eccentric weight located within a connector that has a higher e-modulus than the housing material, allowing for efficient vibration transfer to the head without significant absorption, even when the handle is held tightly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is located in the handle housing with a chassis interface, then the structure is stable and easy to manufacture, but vibrations are absorbed at the chassis-housing interface leading to reduced vibration amplitude at the brush head
Solution Approach 1:
The motor is extracted from the handle housing and relocated to the brush head, specifically positioned near the bristle carrier. This removes the motor from the vibration path between the handle and brush head, eliminating the chassis-housing interface that absorbs vibration energy. The motor directly drives the brush head, ensuring maximum vibration transmission without energy loss at intermediate interfaces.
Solution Approach 2:
A dedicated vibration transmission element (such as a vibration transmission shaft or direct coupling mechanism) is introduced as an intermediary between the motor and the brush head. This intermediary is specifically designed to transmit vibrations efficiently with minimal energy loss, replacing the indirect transmission path through the handle housing and chassis interface.
2Reliability
If the motor is located within the brush neck, then vibrations are directly transmitted to the head, but the neck becomes bulky and large in cross section impeding maneuverability and reachability
Solution Approach 1:
The motor is positioned locally at the very tip of the brush head, close to the bristle carrier, rather than distributing it throughout the neck. This localized positioning allows the neck to maintain a slim, curved profile for good maneuverability, while the motor is confined to a compact space at the head where it directly drives the bristles without requiring a bulky neck structure.
Solution Approach 2:
The motor placement transitions from a longitudinal arrangement (motor in the neck extending from the handle) to a transverse arrangement (motor at the tip of the head near the bristle carrier). This dimensional change allows the neck to remain slender and curved for maneuverability, while the motor is positioned in a different spatial dimension that enables direct vibration transmission to the bristles.
3Ease of operation
If the user holds the handle tightly, then control is improved, but vibrations are significantly damped reducing brush head vibration
Solution Approach 1:
The motor is extracted from the handle and relocated to the brush head, removing it from the user's grip area. This separates the vibration generation source from the user's hand, so that tight gripping no longer damps the vibrations. The user can maintain firm control of the handle without affecting the vibration amplitude at the brush head, as the motor now directly drives the head independent of handle vibrations.
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 design enhances in-mouth perception and cleaning performance by maintaining vibration amplitude independent of the user's grip and allows for a slim, curved neck design that improves maneuverability and reachability during brushing.
Implementation Method 1
a motor (34) comprising an eccentric weight (35) for operating the personal care implement
Data Source
Figure 1~2
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AI summary
A handle for an electrically operated personal care implement comprises: - a housing comprising an inner cavity, the housing having a proximal end and a distal end opposite the proximal end, - a connector for repeatably attaching and detaching a head to and from the handle, the connector being partially accommodated within the inner cavity at the proximal end of the housing, - a motor comprising an eccentric weight for operating the personal care implement, the motor being accommodated within the inner cavity of the housing, wherein - the connector comprises a recess accommodating the motor with the eccentric weight.