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CN-115515667-B - Automatic injector assembly

CN115515667BCN 115515667 BCN115515667 BCN 115515667BCN-115515667-B

Abstract

An auto-injector assembly (100) includes a housing (102), a syringe assembly (202) to store a predetermined volume of medication to be administered, a needle guard (212) to surround the syringe assembly (202) such that a portion of the needle guard (212) is adapted to extend out of the housing (102) in an initial state and retract into the housing (102) when the portion is pressed onto an injection site, a spring retainer (218) to retain a dose delivery spring (216) in a compressed state, a locking unit (220) to retain the spring retainer (218) in a locked state, and a plunger (222) engaged with the spring retainer (218) and adapted to move toward the syringe assembly (202) when the spring retainer (218) is unlocked. The engagement position of the plunger (222) with the spring retainer (218) is adapted to be changed in order to control the travel distance of the plunger (222) within the housing (102) based on a predetermined volume of medicament in the syringe assembly (202).

Inventors

  • J. M. Shank Assetti
  • S. Jagiri
  • A. N.C. Rao
  • S. P. Tamby
  • A. K.H. Sadahiwa

Assignees

  • 拜康生物制品有限公司

Dates

Publication Date
20260505
Application Date
20210514
Priority Date
20200515

Claims (8)

  1. 1. An automatic injector assembly (100), comprising: a housing (102) having a proximal end (104) and a distal end (106); A syringe assembly (202) disposed adjacent the proximal end (104) of the housing (102) and adapted to store a predetermined volume of medicament to be administered through a needle (406); A needle guard (212) arranged around the syringe assembly (202) such that a portion of the needle guard (212) is adapted to extend out of the housing (102) in an initial state and retract into the housing (102) when the portion is pressed onto an injection site; a spring holder (218) arranged adjacent to the distal end (106) of the housing (102) and adapted to hold a dose delivery spring (216) in a compressed state; a locking unit (220) disposed within the spring holder (218) and adapted to hold the spring holder (218) in a locked state with the housing (102), and A plunger (222) engaged with the spring retainer (218) and adapted to move toward the syringe assembly (202) when the spring retainer (218) is unlocked, wherein an engaged position of the plunger with the spring retainer (218) is adapted to be changed to control a travel distance of the plunger (222) within the housing (102) based on the predetermined volume of the medicament in the syringe assembly (202), Wherein the dose delivery spring (216) is arranged between an inner surface of the housing (102) and an outer surface of the spring holder (218), The housing (102) having a pair of stops (402) formed on an inner surface, the spring retainer (218) including a pair of arms (404) adapted to engage the pair of stops (402) to lock the spring retainer (218) with the housing (102) to limit movement of the plunger (222), Wherein the needle guard (212) is adapted to push the locking unit (220) further into the spring holder (218) upon retraction, thereby unlocking the spring holder (218) from the housing (102) such that the plunger (222) moves towards the syringe assembly (202) for administering the medicament into the injection site.
  2. 2. The automatic injector assembly (100) of claim 1, wherein the needle guard (212) is adapted to be pressed against the injection site to extend the needle (406) of the syringe assembly (202) for insertion into the injection site and return to an original position after administration of the medicament.
  3. 3. The automatic injector assembly (100) of claim 1, comprising: a syringe retaining member (210) adapted to support the syringe assembly (202) within the housing (102), and A needle guard spring (214) adapted to be arranged between an inner surface of the housing (102) and an outer surface of the needle guard (212), wherein the needle guard spring (214) is adapted to support movement of the needle guard (212) within the housing (102) for administering the medicament.
  4. 4. The automatic injector assembly (100) of claim 1, wherein the plunger (222) has a plurality of threads formed on an inner surface, the spring retainer (218) includes a shaft (224), the shaft (224) is adapted to engage the plurality of threads of the plunger (222), and the plunger (222) rotates into the shaft (224) to control the travel distance of the plunger (222) within the housing (102) to administer the medicament into the injection site based on the predetermined volume of the medicament in the syringe assembly (202).
  5. 5. The automatic injector assembly (100) of claim 1, wherein the spring retainer (218) is adapted to unlock, thereby releasing the dose delivery spring (216) from the compressed state, and pushing the plunger (222) toward the syringe assembly (202) based on a compression force of the dose delivery spring (216).
  6. 6. The automatic injector assembly (100) of claim 1, comprising: a needle shield (408) adapted to enclose the needle (406), and A cap (208) secured to the needle shield (408) and adapted to close the proximal end (104) of the housing (102) when not in use, Wherein the cap (208) and the needle shield (408) are adapted to be removed prior to pressing the needle guard (212) against the injection site for administration of the medicament.
  7. 7. The automatic injector assembly (100) of claim 3, comprising: the cartridge holder (210) having a locking portion (802) formed on an outer surface, and The needle guard (212), comprising: A longitudinal groove (804) adapted to receive the locking portion (802) of the syringe holder (210), wherein the locking portion (802) is adapted to travel along the longitudinal groove (804) so as to accommodate relative movement of the needle guard (212) with respect to the syringe holder (210) when the needle guard (212) is retracted into the housing (102), and A longitudinal slot (806) formed adjacent to the longitudinal groove (804) and adapted to accommodate return travel of the locking portion (802) when the needle guard (212) is moved back to an original position after administration of the medicament, wherein the longitudinal slot (806) comprises a stop slot (808) adapted to retain the locking portion (802) at the end of return travel, thereby limiting further movement of the needle guard (212) once the medicament is administered.
  8. 8. The automatic injector assembly (100) of claim 1, including a viewing slot (112) formed on the housing (102) to view movement of the plunger (222) from the outside.

Description

Automatic injector assembly Technical Field The present invention relates to auto-injectors, and more particularly to auto-injector assemblies having plungers and adapted to operate to deliver different volumes of medicament into injection sites. Background Autoinjectors are widely used to deliver drugs directly into patients. A large number of auto-injectors are now available on the market. Existing auto-injectors are primarily capable of delivering a predetermined dose of medication to a patient. Typically, conventional auto-injectors are adapted to deliver a predetermined dose of medication to a patient. It is well known that each drug needs to be delivered to a patient in a different volume. The volume may also vary depending on the patient (e.g., based on the condition and age of the patient). Similarly, there are a number of other factors that may be used in determining the dosage of a drug to be injected into a patient. Thus, for effective treatment, it may be necessary to deliver the same drug to different patients in different volumes. However, manufacturers need to manufacture specific auto-injectors for a predetermined volume of medicament to be administered. Thus, delivering a specific volume of drug would require constructing a specific auto-injector capable of delivering a predetermined dose to a patient. Due to this constructional limitation, multiple auto-injectors are required for doses of different volumes. Thus, it is inconvenient for consumers to purchase, operate and maintain a plurality of auto-injectors. On the other hand, pharmaceutical manufacturers must also manufacture a plurality of auto-injectors for different drugs requiring different dose settings. For example, in terms of the infrastructure of a manufacturing plant, the manufacturer may have to make considerable effort and investment. There are several device manufacturers that offer modifications to the constituent components of an auto-injector to allow for the setting of variable doses of medicament for delivery. However, the manufacture of such auto-injectors requires significant assembly line changes at the manufacturing facility. Thus, the overall operating costs of the auto-injector are also high. Disclosure of Invention This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description of the invention. This summary is not intended to identify key or essential inventive concepts of the invention, nor is it intended to be used to identify the scope of the invention. In one embodiment of the present invention, an automatic injector assembly is disclosed. The auto-injector assembly comprises a housing having a proximal end and a distal end, a syringe assembly arranged adjacent the proximal end of the housing and adapted to store a predetermined volume of medicament to be administered through the needle, a needle guard arranged around the syringe assembly such that a portion of the needle guard is adapted to extend out of the housing in an initial state and retract into the housing when the portion is pressed onto an injection site, a spring holder arranged adjacent the distal end of the housing and adapted to hold the dose delivery spring in a compressed state, a locking unit arranged within the spring holder and adapted to hold the spring holder in a locked state with the housing, and a plunger engaged with the spring holder and adapted to move towards the syringe assembly when the spring holder is unlocked. The engagement position of the plunger with the spring retainer is adapted to be changed in order to control the travel distance of the plunger within the housing based on a predetermined volume of medicament in the syringe assembly. The needle guard is adapted to push the locking unit further into the spring holder upon retraction, unlocking the spring holder from the housing such that the plunger moves towards the syringe assembly for administration of the medicament into the injection site. To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which the invention is described. Drawings These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: FIG. 1 illustrates a perspective view of an auto-injector assembly according to an embodiment of the present invention; FIG. 2 illust