CN-224207182-U - Needle retracting spring locking excitation mechanism for automatic injection pen

CN224207182UCN 224207182 UCN224207182 UCN 224207182UCN-224207182-U

Abstract

The utility model provides a locking and exciting mechanism of a needle retracting spring for an automatic injection pen, which comprises a push rod, a retracting sleeve, a needle retracting spring base, a needle retracting spring and the like, wherein the needle retracting spring base is arranged around the needle retracting spring, so that the locking can ensure safety and can not be easily triggered and unlocked, the unlocking excitation can be realized only when the push rod pushes medicine for injection, the needle retracting spring can automatically provide thrust during the unlocking excitation, the dependence on the elastic force of the end section of the injection spring can be eliminated, and the unlocking excitation process is convenient and quick.

Inventors

LIN XIAO
XIE KAI
FU WEI

Assignees

苏州赛卫生物科技有限公司

Dates

Publication Date: 20260508
Application Date: 20250108

Claims (4)

1. The needle retracting spring locking and exciting mechanism for the automatic injection pen is characterized by comprising a push rod, a retracting sleeve, a needle retracting spring base and a needle retracting spring; The needle retracting spring base is a cylinder with two open ends and is provided with a spring cylinder, and the bottom of the spring cylinder extends outwards to form a spring seat; The needle retracting spring is sleeved on the spring cylinder, and the bottom of the needle retracting spring is propped against the spring seat; The inside of the spring cylinder is a connecting cavity; The lower part of the retraction sleeve is provided with a step surface, and the top of the needle retraction spring is propped against the step surface; A connecting cylinder is arranged below the step surface of the retraction sleeve, and the diameter of the connecting cylinder is smaller than the step surface and the inner diameter of the spring cylinder; The lower part of the connecting cylinder of the retraction sleeve is an elastic retraction fixing claw, the bottom of the retraction fixing claw is outwards protruded to form a retraction fixing hook, and the upper part of the retraction fixing hook is provided with an inclined retraction guide; a push rod guide cavity is formed in the connecting cylinder and the retracting fixed claw; the lower part of the push rod is provided with a push rod barrel which is a cylinder barrel and can slide along the axis in the push rod guide cavity; The top of the push rod barrel of the push rod is provided with an axial abdication cavity, and the abdication cavity and the narrowing fixed claw are positioned in the same direction.
2. The retracting spring locking and activating mechanism for an automatic injection pen according to claim 1, wherein a spring seat of the retracting spring base extends outwards to form a base fixing claw; the needle retracting spring base is fixedly arranged in the pen shell through a base fixing claw; the bottom of the needle retracting spring is fixed on the needle retracting spring base, and the needle retracting spring can be unfolded upwards.
3. The retracting spring locking activation mechanism for an automatic injection pen according to claim 1, wherein the top portion of the push rod extends outwardly forming a fixed jaw sized to be larger than the inner diameter of the barrel of the retracting sleeve.
4. The retracting spring locking and activating mechanism for an automatic injection pen according to claim 1, wherein a piston cone is arranged at the bottom of the push rod and fixedly connected with a piston of the injector.

Description

Needle retracting spring locking excitation mechanism for automatic injection pen Technical Field The utility model relates to a mechanism for locking and exciting a needle retracting spring, which is applied to an automatic injection pen, and belongs to the field of medical injectors. Background An automatic injection pen is an injector product which is convenient for patients or common people to operate, and when in production, manufacturers firstly fill liquid medicine into the injector to form a prefilled injector (PREFILLED SYRINGE, PFS, also called as a medicine carrying injector) as shown in figure 4, and then put PFS into an automatic injection device to form the automatic injection pen for transportation and sale. Compared with the traditional injector, the automatic injection device omits the processes of sucking, inserting and pushing the medicine by a disposable injector, has more convenient operation, ensures the injection dosage and does not cause deviation of the injection dosage due to unskilled operation. At present, a plurality of automatic injection pens for PFS with a disposable full-automatic injection function exist in the market, and the use of patients is convenient. However, because of the legal requirements, the needle needs to be shielded before and after use to avoid injury to the person, 2 sets of spring systems are generally needed inside to respectively implement the functions of pushing medicine for injection and pulling needle for shielding, so the structure of the automatic injection pen is generally complex, which results in that the automatic injection device is also complex when assembled with the PFS. In particular, the needle retracting spring needs to be reliably locked in the transportation process, and also keeps the reliable locking in the use front section (needle insertion and medicine pushing injection) of the automatic injection pen, and needs to be timely unlocked for unfolding once medicine pushing injection is completed, so that the needle retracting action (needle pulling and needle hiding) is realized. Therefore, the locking and exciting mechanism of the needle retracting spring needs to be skillfully designed to realize reliable safe locking and convenient and quick unlocking. The existing automatic injection pen often utilizes the back-end elasticity of the unfolding operation of the injection spring to unlock the locking mechanism of the retracting spring, but under the condition that enough unlocking force can be provided, the elasticity of the whole injection spring is extremely large, and the residual force of the injection spring cannot influence the unfolding and retracting operation of the retracting spring, so that the mechanism is complex. For the above situation, it is necessary to design a more ingenious mechanism to perform safe locking and unlocking excitation on the needle retracting spring. Disclosure of utility model The utility model aims to provide a locking and exciting mechanism of a narrowing spring for an automatic injection pen, which is arranged around the narrowing spring, so that the locking can be ensured to be safe and not to be easily triggered to unlock, the unlocking excitation can be realized only when the push rod pushes medicine to complete injection, the narrowing spring provides thrust during unlocking excitation, the dependence on the elastic force of the end section of the injection spring can be eliminated, and the unlocking excitation process is convenient and quick. In order to achieve the above-mentioned purpose, the utility model provides a needle retracting spring locking and exciting mechanism for an automatic injection pen, comprising a push rod, a retracting sleeve, a needle retracting spring base and a needle retracting spring; The needle retracting spring base is a cylinder with two open ends and is provided with a spring cylinder, and the bottom of the spring cylinder extends outwards to form a spring seat; The needle retracting spring is sleeved on the spring cylinder, and the bottom of the needle retracting spring is propped against the spring seat; The inside of the spring cylinder is a connecting cavity; The lower part of the retraction sleeve is provided with a step surface, and the top of the needle retraction spring is propped against the step surface; A connecting cylinder is arranged below the step surface of the retraction sleeve, and the diameter of the connecting cylinder is smaller than the step surface and the inner diameter of the spring cylinder; The lower part of the connecting cylinder of the retraction sleeve is an elastic retraction fixing claw, the bottom of the retraction fixing claw is outwards protruded to form a retraction fixing hook, and the upper part of the retraction fixing hook is provided with an inclined retraction guide; a push rod guide cavity is formed in the connecting cylinder and the retracting fixed claw; the lower part of the push rod is provided with a push rod ba