Applicator Device Rotatable Part Hollow Shaft Connection
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Solution Overview
Problem
Conventional cosmetic applicator devices require a substantial rear portion to accommodate the threaded spindle, leading to increased length and handling issues due to the need for a long threaded spindle to convey the stick mass, which restricts design freedom in the rear portion.
Innovation Solution
The applicator device features a rotatable part with a hollow shaft connected via an axially fixed rotatable connection, utilizing a telescopic section and positive engagement surfaces to convert rotational movement into axial displacement, reducing the length required for the advance mechanism and allowing for a more flexible design of the rear portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a long threaded spindle is used to convey the entire stick mass out of the applicator device, then the stick mass can be completely applied, but the overall length of the applicator device increases significantly
Solution Approach 1:
The threaded spindle is divided into two functional sections: a first threaded section that engages with the rotatable part to convert rotation into axial movement, and a second threaded section that engages with the stick mass. This segmentation allows the spindle to convey the stick mass effectively while maintaining a compact overall length by distributing the threading function across different engagement points.
Solution Approach 2:
The intermediate member with the ball-and-socket joint is nested within the hollow shaft structure, allowing the threaded spindle to pass through and engage with both the rotatable part and the stick mass without requiring excessive length. The intermediate member is positioned axially between the rotatable part and the stick mass, creating a compact nested arrangement that reduces the overall device length while maintaining full functionality.
2Productivity
If a long threaded spindle with intermediate members and fixing members is used, then the stick mass can be conveyed completely, but the device complexity increases
Solution Approach 1:
The threaded spindle serves multiple functions simultaneously: it acts as both the rotating element that converts rotational movement into axial displacement through its first threaded section, and as the pushing element that conveys the stick mass through its second threaded section. This multi-functionality eliminates the need for separate fixing members and intermediate members required in conventional designs, thereby reducing device complexity while maintaining complete stick mass application capability.
Solution Approach 2:
The functions of the threaded spindle, the pusher mechanism, and the rotational-to-axial conversion mechanism are merged into a single integrated component. The threaded spindle combines the rotational engagement surface, the axial pushing surface, and the intermediate connection function into one element, simplifying the overall device structure while ensuring complete conveyance of the stick mass.
3Productivity
If the rear portion is dimensioned sufficiently long to accommodate the threaded spindle, then the stick mass can be conveyed completely, but the design freedom of the rear portion is restricted
Solution Approach 1:
The threaded spindle is designed with a dynamic functional arrangement where the first threaded section engages with the rotatable part at one axial position and the second threaded section engages with the stick mass at another axial position. This dynamic functional distribution allows the rear portion to be designed with greater flexibility, as the critical functions are achieved through the rotational-to-axial conversion mechanism rather than requiring a long fixed-dimensional rear portion.
Solution Approach 2:
The invention changes the critical parameter from the axial length of the rear portion to the threading geometry and engagement characteristics of the threaded spindle. By optimizing the thread pitch, engagement depth, and rotational-to-axial conversion ratio, the design achieves complete stick mass conveyance with a shorter, more design-flexible rear portion that can be adapted to various cosmetic application needs.
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 significantly reduces the overall length of the applicator device, providing greater freedom in designing the rear portion and improving handling characteristics while maintaining effective axial movement of the stick mass, thus enhancing usability and cosmetic application efficiency.
Implementation Method 1
an axially fixed rotatable connection between the rotatable part and the hollow shaft, in a region in which the hollow shaft and the rotatable part engage with each other
Data Source
Figure 1~2
Figure 3~5
Figure 6a~6c
AI summary
An applicator device for applying a mass in the form of a stick (1) extending longitudinally along a longitudinal axis (M), comprising a rotatable part (10) through which the stick (1) is guided and which has an exit opening (12) for the stick (1), a hollow shaft (41) coupled to the rotatable part (10) via an axially fixed rotatable connection for axially advancing the stick (1), a body (20) fixedly connected to the hollow shaft (41), and a cap (30) for the rotatable part (10), which is detachably connected to the hollow shaft (41), the axially fixed rotatable connection being formed by a coupling portion of the rotatable part (K.2) and a complementary counterpart coupling portion (K.1) of the hollow shaft (41) in a coupling portion (K) in which the hollow shaft (41) and the rotatable part (10) engage with each other.