Improved-type positive-pressure-retraction-type safe injector

Abstract

Disclosed is an improved-type positive-pressure-retraction-type safe injector. The improved-type positive-pressure-retraction-type safe injector is composed of a guard sleeve, a sealing gasket, a needle tubing, a needle seat, a damping ring, a piston, a pushing rod and an outer barrel. The sealing gasket ensures that an air-tight seal is formed between the connection portion of the front segment and the middle segment of the needle seat and an inner hole of a cone head of the outer barrel. The inner diameter of the damping ring is slightly smaller than the outer diameter of the rear segment of the needle seat but is larger than the outer diameter of the middle segment of the needle seat. The damping ring is sleeved on the bottom of the lower end of the needle seat and then is arranged inside the front end of the outer barrel to ensure that air-liquid seal is formed among the needle seat, the damping ring and the outer barrel. An annular groove is arranged on the surface of the piston. The diameter of the piston is slightly larger than the inner diameter of the outer barrel. The piston and the pushing rod are arranged inside the inner cavity of the outer barrel and are tightly matched with the inner wall of the outer barrel in a sliding mode. After injection is conducted, a user continues squeezing the pushing rod; the surface of the piston can be cut into a window by a sharp skirt edge of the lower end of the needle seat and a sharp edge of an inner hole of the pushing rod; the pushing rod ensures that the damping ring moves forwards to compress air in the inner cavity of the front segment of the outer barrel; when the damping ring moves forwards to the middle segment of the needle seat, the needle seat is released, compressed air ejects the needle seat needle into the inner cavity of the pushing rod, the window of the piston is recovered to ensure that the needle is shielded and can not be exposed outwards. The improved-type positive-pressure-retraction-type safe injector has the advantages of being simple, practical, low in cost, safe and reliable.

Description

(1) Technical field [0001] The invention relates to a medical device, in particular to an improved positive pressure retractable safety syringe used in the puncture process of human tissue and injecting medicine into the tissue or extracting tissue samples after puncture. (two), background technology [0002] Chinese Patent Application No. 201210221311.1 discloses a pneumatic retractable self-destructing syringe, which includes a syringe, a cylindrical hollow injection rod, a needle seat, a gasket, a piston and a sealing joint. The sealing gasket at the lower end is installed on the front end of the injection barrel, the piston sleeve is set on the outside of the front end of the injection rod, the sealing joint is set on the inner side of the front end of the injection rod, and the sealing joint and the needle seat are provided with a connecting structure that cooperates with each other. It is characterized in that : When the injection rod is pushed to the front end of the ...

AI Technical Summary

Problems solved by technology

[0003] Although this technical solution has made great progress compared with previous self-destruct or safety syringes that use mechanical force (spring force or artificial pulling force) to retract the needle seat and needle tube, it still has the following deficiencies: 1. The front end of the needle seat and the front end of the syringe Relying on the slope and when the injection rod is pushed to the front end of the injection cylinder, the pressure of the injection rod on the inner wall of the needle seat and the front end of the outer cylinder is used to form a seal between the two. In the process of industrial production of large-scale injection molding parts, there are parts The mutual error of the size will make the above-mentioned seal uncertain, and the seal will not be completely reliable, which will reduce the air compression degree and air pressure in the inner cavity of the front end of the syringe, and the needle seat cannot be ejected and retracted;② , In this scheme, the protrusion at the lower part of the needle seat forms a limit seat, which only cooperates with the gasket to complete the air seal between the needle seat and the inner wall of the injection barrel, and limits the needle seat so that it cannot move backward

Therefore, the description of the above-mentioned technical solution is only that the sealing gasket moves forward from the position-limiting seat to the middle of the needle seat. This distance is difficult to achieve the required pressure for the compression of the air in the inner cavity of the front end of the syringe, especially for small specifications (less than 1.0ml) of the syringe, the diameter of the inner cavity of the injection barrel is less than 4.0mm, and the thickness of the general gasket is about 2-3.0mm; such a compression distance, the air pressure is extremely weak, and the needle seat retraction described in the above scheme cannot be realized Required; ③, because this scheme utilizes the structure that the inner hole at the lower end of the needle seat and the plug at the front end of the sealing joint are connected to each other, so that the two can drive the needle tube to retract together into the inner cavity of the injection rod; due to the gap between the inner hole of the needle seat and the sealing joint The existing connection space will increase the drug residue, especially the expensive drug, which will cause drug waste and reduce the curative effect; ④, because this scheme uses the interaction between the bottom edge of the sealing joint and the three convex ribs in the middle and lower parts of the injection rod. function, to realize the limit of the needle, so that it cannot be shot from the lower end of the injection rod, and at the same time cannot be exposed from the upper hole of the injection rod

Due to the deficiencies or defects of the above-mentioned ① and ② in this solution, its retraction is uncertain, especially when the small-sized syringe does not retract; then the needle, the needle seat and the sealing joint are retracted (injected) together. Possibility: Incomplete entry into the inner cavity of the injection rod, that is, the needle, the needle seat and the sealing joint are not ejected by enough compressed air and retracted between the two stoppers, then the needle tip cannot fully enter the inner cavity of the injection rod , and continue to be exposed, there is a risk of needle stick injury

Images