Rotary Syringe Nut Retaining Surfaces
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Solution Overview
Problem
Rotary syringes used for dispensing pasty and flowable dental substances face issues with the reliability of the connection between the nut part and the syringe body, leading to potential loosening during material expulsion, and require improvements in hygiene, handling, and assembly simplicity.
Innovation Solution
A rotary syringe design featuring a nut part with retaining surfaces and counter-retaining surfaces that form a positive fit, preventing axial and radial displacement, and a connecting mechanism that ensures secure attachment, along with a cover mechanism to enhance hygiene and ease of use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw connection is used to attach the nut part to the syringe body, then the connection can be securely formed, but the screw connection can be unintentionally loosened during actuation
Solution Approach 1:
The connection mechanism is segmented into multiple independent retaining surfaces (first retaining surface, second retaining surface, third retaining surface, fourth retaining surface) that work together to prevent different types of displacement (axial and radial), eliminating the need for a screw connection and its associated loosening problem
Solution Approach 2:
The retaining surfaces are pre-configured on the nut part and syringe body to automatically prevent displacement upon assembly, without requiring additional fastening actions during operation that could lead to loosening
2Ease of manufacture
If the nut part is pushed onto the syringe body in a radial direction, then assembly is simplified, but axial displacement of the nut part can occur during actuation
Solution Approach 1:
The solution addresses the radial assembly approach by adding axial constraint through retaining surfaces arranged in multiple dimensions (axial and radial directions), preventing displacement in both directions while maintaining the simple radial push-on assembly method
3Reliability
If retaining surfaces are added to prevent displacement, then connection reliability is improved, but device complexity increases
Solution Approach 1:
Multiple retaining surfaces (first, second, third, and fourth) are merged into a single integrated connection mechanism between the nut part and syringe body, achieving comprehensive displacement prevention without proportionally increasing complexity
Data Source
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AI summary
Rotary syringe (100) comprising a piston spindle (200) with an external thread (210), a syringe body (300) comprising a sleeve (310) with a piston end (360), and a nut part (400) with an internal thread (410), wherein the nut part (400) is pushed onto the piston end (360) in a radial sliding direction (303), wherein the nut part (400) has a flange (440) which forms a positive fit with a counter surface (340) on the piston end (360) such that axial displacement of the nut part (400) relative to the syringe body (300) in the exit direction (302) is prevented, and the nut part (400) has retaining surfaces (420a,b) which form a positive fit with counter surfaces (320a,b) of the piston end (360) such that axial displacement of the nut part (400) is prevented. (400) is prevented from moving against the syringe body (300) in the direction of exit (302), and the retaining surfaces (420a,b) and counter-retaining surfaces (320a,b) form a positive fit such that a radial,Relative movement between the holding surfaces and the counter-holding surfaces, directed perpendicular to the sliding direction, is prevented.