Injection-Molded Motion Converter for Stable Reciprocating Drive
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Solution Overview
Problem
Existing drive units for personal care devices face challenges in manufacturing complexity and cost due to intricate mechanisms for converting rotary motion into linear reciprocating motion.
Innovation Solution
A plastic injection molded motion converter with a deformable unit and U-shaped receivers, featuring a bracing element to stabilize the U-legs, allowing for easy manufacturing and effective conversion of rotary motion into linear reciprocating motion using a standard DC motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a standard DC motor with a plastic injection molded motion converter is used, then manufacturing complexity and cost are reduced, but the conversion of rotary motion to linear reciprocating motion must remain effective
Solution Approach 1:
The patent combines multiple functional elements into a single integrated motion converter component made via plastic injection molding. The deformable unit, U-shaped receivers, and bracing elements are merged into one piece, eliminating the need for separate manufacturing and assembly steps for each component, thus reducing manufacturing complexity while maintaining functional effectiveness.
Solution Approach 2:
The motion converter is designed as a universal component that can be used with standard DC motors in various personal care devices. The plastic injection molded design with standardized features (U-shaped receivers, deformable unit) allows it to serve multiple functions: motion conversion, structural support, and noise/vibration reduction, simplifying the overall system while maintaining reliability.
2Ease of manufacture
If a plastic injection molded motion converter is used, then manufacturing cost is reduced, but the structural stability during motion conversion must be maintained
Solution Approach 1:
The motion converter is segmented into functional zones within the single molded piece: the deformable unit for motion conversion, the U-shaped receivers for mounting and stability, and the bracing element for structural reinforcement. This segmentation allows each zone to be optimized for its specific function while being manufactured as one cost-effective integrated component.
Solution Approach 2:
The patent uses plastic material with appropriate mechanical properties for injection molding, combining rigidity for structural stability with flexibility for the deformable unit. The material selection and molding process create a composite structure that maintains strength while reducing manufacturing cost compared to metal alternatives.
3Object-generated harmful factors
If the U-shaped receivers are stabilized with a bracing element, then noise and vibration are reduced, but the device complexity increases
Solution Approach 1:
The bracing element is merged into the same plastic injection molded component as the U-shaped receivers and deformable unit. This integration means the bracing structure is formed during the molding process itself, adding noise and vibration reduction functionality without requiring separate parts or assembly steps, thus avoiding increased device complexity.
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 solution provides a cost-effective and efficient conversion of rotary motion to linear reciprocating motion, suitable for personal care devices, with improved manufacturing ease and reduced noise and vibration.
Implementation Method 1
a deformable unit (50C) that is connected with the connector unit (8C), the mounting unit (60C) and the coupling unit (59C)
Implementation Method 2
a motor shaft extension (40C) coupled to or connected with the motor shaft (31C), the motor shaft extension (40C) comprising at least a first eccentric shaft element (41C) that is arranged eccentrically with respect to the longitudinal center axis so that it moves on a circular path around the longitudinal center axis in operation
Data Source
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AI summary
motion converter (5A, 5B, 5C, 5D, 8C) structured for converting a rotational motion provided by a motor shaft (31A, 31B, 31D, 3) into a linear reciprocating motion of a drive shaft (70A, 70B, 70D). The motion converter (5A, 5B, 5C, 5D, 8C) has a deformable unit (50A, 50B, 50C, 50D, 8C), a mounting unit (60A, 60B, 60D) connected with the deformable unit (50A, 50B, 50C, 50D, 8C), a coupling unit (59A, 59B, 59C, 59D, 8A) connected with the deformable unit (50A, 50B, 50C, 50D, 8C), the coupling unit (59A, 59B, 59C, 59D, 8A) being structured to receive the drive shaft (70A, 70B, 70D) or the coupling unit (59A, 59B, 59C, 59D, 8A) comprising the drive shaft (70A, 70B, 70D), a connector unit (8A, 8B, 8C, 8D) connected with the deformable unit (50A, 50B, 50C, 50D, 8C), the connector unit (8A, 8B, 8C, 8D) comprising at least a first essentially U-shaped receiver (90E) being structured for receiving a first eccentric shaft element (41A, 41B, 41D) of the motor shaft (31A, 31B, 31D, 3) and having a U-base and two U-legs together defining a first elongated hole (804B, 805B, 814B, 902E) having a length (1), a width and a height, and a first bracing element (903E) that connects the two U-legs of the first essentially U-shaped receiver (90E) on their free ends such that access into the first elongated hole (804B, 805B, 814B, 902E) across the width and the height of the first elongated hole (804B, 805B, 814B, 902E) is provided, preferably where the first bracing element (903E) is bar-shaped or U-shaped or O-shaped, and where the length (1) is measured from an inner surface of the U-base to the free ends of the U-legs.