CN110841150B - A drug delivery device - Google Patents

Abstract

The invention relates to the technical field of medical equipment, in particular to a drug delivery device, which comprises a cylinder body with a piston cavity, a piston, a seal head assembly and an elastic element, wherein the piston is abutted against the seal head assembly by the elastic element, so that a gas flow channel of a gas energy storage cavity is blocked by a sealing element; the elastic element can realize automatic reset of the piston after injection, and is convenient and quick to use; meanwhile, the rodless cavity is exhausted cleanly, the sealing performance of the airflow channel is excellent and reliable, and the injection success rate and the accuracy are high.

Description

A drug delivery device

Technical Field

The present invention relates to the technical field of medical devices, in particular to a drug delivery device.

Background Art

With the development of science and technology, my country has become one of the few countries in the world that can produce needle-free syringes. It mainly uses the principle of high-pressure jet to form a thinner liquid flow to instantly penetrate the skin and reach the subcutaneous tissue. It has the advantages of uniform liquid diffusion, fast onset time, high drug absorption rate and small wound.

Existing pen-type needle-free injectors generally use magnetic force to reach a predetermined firing pressure, such as the pneumatic magnetic energy storage needle-free injector disclosed in the Chinese patent document with publication number CN203861700U. This needle-free injector uses the magnet on the rear end cover to cooperate with the impact piece that can be attracted by magnetic force, so that when the air pressure in the air flow channel reaches a certain value so that the driving force acting on the impact piece overcomes the magnetic force of the magnet on it, the impact piece breaks away from the magnet and impacts forward to achieve the injection of the liquid medicine. That is, the impact piece is locked by magnetic force to prevent the impact piece from moving in advance when the air source pressure has not yet risen to a sufficient level; the disadvantages of this type of needle-free injector are: when the firing pressure required by the injection target is large, the magnetic force required by the magnet is bound to be large, resulting in the need to increase the volume of the magnet, which in turn causes the volume of the injector to become larger, which is not conducive to the compact and delicate design of the injector.

Summary of the invention

The technical problem to be solved by the present invention is: in order to solve the problem that the needle-free syringe in the prior art adopts a magnetic locking impact piece, which causes the size of the syringe to become larger due to the increase in the volume of the magnet when the required firing pressure is larger, a drug delivery device is provided, which can be used for drug solution injection in humans, livestock, pets, etc.

The technical solution adopted by the present invention to solve the technical problem is: a drug delivery device, comprising a cylinder with a piston cavity, a piston, a head assembly and an elastic element, wherein the piston is slidably arranged in the piston cavity, the head assembly and the elastic element are respectively arranged at both ends of the piston, and the head assembly has an air inlet, a gas energy storage cavity and an air flow channel which are interconnected, and the air inlet is used to allow the gas of the gas source to pass into the gas energy storage cavity;

The portion of the piston chamber between the piston and the head assembly is a rodless chamber, and a seal is provided between the piston and the head assembly. The elastic element abuts the piston against the head assembly so that the seal blocks the air flow channel of the gas energy storage chamber. When the gas in the gas energy storage chamber is stored to the point where its pressure overcomes the elastic force of the elastic element, the piston is fired and the air flow channel is connected to the rodless chamber.

In this solution, elastic force is cleverly used to store energy in the piston to a predetermined firing pressure, so that the space in the axial direction of the cylinder can be fully utilized by the elastic element, and an elastic element with greater elasticity can be installed without increasing the outer diameter of the cylinder, thereby enabling the piston to obtain a greater firing pressure with a smaller diameter cylinder, thereby improving the compactness of the structure and facilitating a small and refined design. Among them, storing energy through elastic force can also relatively improve the stability of the firing, and the elastic element can realize automatic resetting of the piston after injection, which is convenient and quick to use.

Furthermore, the head assembly includes a head and an energy storage plug. The head is fixedly mounted on the upper end of the cylinder, and the energy storage plug is fixed on the head to form the gas energy storage chamber between the head and the energy storage plug.

How to ensure that after the gas is introduced into the gas energy storage chamber, the air flow channel will not leak in advance, and the gas in the rodless chamber can be exhausted as much as possible after the piston is reset, which is also a key point and difficulty of the present invention, and is also the key to ensure that the injection can be completed smoothly. The specific problems are as follows: First, the air flow channel of the gas energy storage chamber leaks in advance when the gas energy storage chamber is storing energy, which will cause the piston to inject at a pressure lower than the predetermined firing pressure, which will cause the drug solution to fail to penetrate the epidermis, resulting in injection failure; Second, the gas in the rodless chamber cannot be exhausted after the piston is reset, and the unexhausted gas in the rodless chamber will offset a part of the elastic force of the elastic element, causing the piston to inject at a pressure lower than the predetermined firing pressure during the next injection, which will also cause the drug solution to fail to penetrate the epidermis, resulting in injection failure;

In view of this, the following further technical solutions of the present invention are intended to solve the above problems, which are as follows:

Furthermore, the airflow channel runs through the lower surface of the energy storage plug, the sealing member is fixed on the piston, and the lower surface of the energy storage plug is opposite to the sealing member; the sealing member directly fits the lower surface of the energy storage plug to form a surface seal, thereby blocking the airflow channel.

Furthermore, a sealing protrusion extends downward from the lower surface of the energy storage plug, and the air flow channel passes through the sealing protrusion. The head assembly is provided with a one-way mechanism that allows gas to enter the gas energy storage chamber from the rodless chamber; thereby, when the piston is reset, the sealing protrusion can pre-press against the seal to block the air flow channel. Due to the setting of the one-way mechanism, as the piston continues to approach the energy storage plug for reset, the gas in the rodless chamber will be discharged to the gas energy storage chamber through the one-way mechanism, and the sealing protrusion presses the seal to the inner concave, forming an end face seal and a circumferential face seal to a certain extent, thereby achieving the goal of completely exhausting the gas in the rodless chamber and at the same time enabling the air flow channel to obtain excellent sealing performance.

Furthermore, an air storage groove is provided on the lower surface of the energy storage plug, and the sealing protrusion is located in the air storage groove; or an air storage groove is provided on the upper surface of the piston.

Furthermore, the one-way mechanism includes a one-way gasket and a one-way spring. The energy storage plug is penetrated by an exhaust hole. One end of the one-way spring abuts against the head or the energy storage plug, and the other end abuts against the one-way gasket. The one-way gasket abuts against the energy storage plug at the upper end of the exhaust hole.

Furthermore, the outer peripheral surface of the sealing protrusion is a conical surface with a larger upper end and a smaller lower end.

Furthermore, a mounting groove is provided on the upper surface of the piston, and the sealing member is embedded in the mounting groove.

Furthermore, an upper protrusion is extended upward from the upper surface of the sealing member, a sealing groove matching the upper protrusion is formed at the lower end of the airflow channel, and the upper protrusion is embedded in the sealing groove.

Furthermore, the elastic element is a spring, one end of the elastic element abuts against the cylinder, and the other end abuts against the piston, and the elastic element is sleeved outside the piston rod of the piston.

Furthermore, the sealing element is a rubber pad.

The beneficial effects of the present invention are as follows: the drug delivery device of the present invention cleverly utilizes elastic force to store energy in the piston to a predetermined firing pressure, so that the space in the axial direction of the cylinder can be fully utilized by the elastic element, and an elastic element with greater elastic force can be installed without increasing the outer diameter of the cylinder, thereby enabling the piston to obtain a greater firing pressure with a smaller diameter cylinder, improving the compactness of the structure, and being conducive to a small and refined design; wherein, storing energy through elastic force can also improve the stability of the firing, and the elastic element can realize automatic resetting of the piston after injection, which is convenient and quick to use; at the same time, the rodless chamber has clean exhaust, the sealing performance of the airflow channel is excellent and reliable, and the injection success rate and accuracy are high.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described below in conjunction with the accompanying drawings and embodiments.

FIG1 is a schematic cross-sectional view of a drug delivery device according to the present invention;

FIG2 is a partial enlarged schematic diagram of A in FIG1 ;

FIG. 3 is a schematic diagram of a drug delivery device in Example 3 of the present invention.

FIG4 is a schematic diagram of a drug delivery device in Example 1 of the present invention;

FIG5 is a schematic diagram of a drug delivery device in Example 4 of the present invention;

FIG. 6 is an exploded schematic diagram of the drug delivery device of the present invention.

In the figure: 1. cylinder, 1-1. piston chamber, 1-2. rodless chamber, 2. piston, 2-1. piston rod, 2-2. mounting groove, 3. elastic element, 4. air inlet, 5. gas energy storage chamber, 6. air flow channel, 7. sealing member, 7-1. upper protrusion, 8. end cap, 9. energy storage plug, 9-1. sealing protrusion, 9-2. exhaust hole, 9-3. sealing groove, 9-4. air storage tank, 10. one-way gasket, 11. one-way spring, 12. core, 12-1. push rod.

DETAILED DESCRIPTION

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams that only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention, and directions and references (e.g., up, down, left, right, etc.) may only be used to help describe the features in the drawings. Therefore, the following specific embodiments are not to be taken in a limiting sense, and the scope of the subject matter claimed is limited only by the attached claims and their equivalents.

Example 1

As shown in Figs. 1, 4 and 6, a drug delivery device comprises a barrel 1 having a piston chamber 1-1, a piston 2, a head assembly and an elastic element 3, wherein the piston 2 is slidably disposed in the piston chamber 1-1, the head assembly and the elastic element 3 are respectively disposed at both ends of the piston 2, and the head assembly comprises an air inlet 4, a gas energy storage chamber 5 and an air flow channel 6 which are interconnected, and the air inlet 4 is used to allow the gas of the gas source to pass into the gas energy storage chamber 5;

The portion of the piston chamber 1-1 between the piston 2 and the head assembly is a rodless chamber 1-2, a seal 7 is provided between the piston 2 and the head assembly, the elastic element 3 abuts the piston 2 against the head assembly, so that the seal 7 blocks the air flow channel 6 of the gas energy storage chamber 5, and when the gas in the gas energy storage chamber 5 is stored to a pressure that overcomes the elastic force of the elastic element 3, the piston 2 is fired, and the air flow channel 6 is connected to the rodless chamber 1-2;

In this embodiment, the elastic element 3 can be specifically a spring, one end of the elastic element 3 abuts against the cylinder 1, and the other end abuts against the piston 2. The elastic element 3 is sleeved outside the piston rod 2-1 of the piston 2.

The head assembly includes a head 8 and an energy storage plug 9, the head 8 is fixedly installed on the upper end of the cylinder 1, the energy storage plug 9 is fixed on the head 8, and the gas energy storage chamber 5 is formed between the head 8 and the head 8; in this embodiment, the energy storage plug 9 can be fixed to the head 8 by means of a threaded connection, and an O-ring can be provided between the outer peripheral surface of the bottom end of the energy storage plug 9 and the head 8 for sealing; the head 8 can also be fixed to the rear end of the cylinder 1 by means of a threaded connection, and an O-ring can be provided between the head 8 and the cylinder 1 for sealing.

As shown in Figure 4, the airflow channel 6 passes through the lower surface of the energy storage plug 9, the seal 7 is fixed on the piston 2, and the lower surface of the energy storage plug 9 is opposite to the seal 7; the seal 7 is directly fitted with the lower surface of the energy storage plug 9 to form a surface seal, thereby blocking the airflow channel 6.

The upper surface of the piston 2 is provided with a mounting groove 2-2, and the seal 7 is embedded in the mounting groove 2-2. Specifically, the seal 7 adopts a rubber pad, and the seal 7 can be fixed in the mounting groove 2-2 of the piston 2 by connecting methods such as snap connection and bonding. In this embodiment, any connection method can be used to fix the seal 7 on the piston 2.

The working principle of this embodiment is as follows:

When in use, the medicine core 12 filled with liquid medicine is connected to the front end of the cylinder 1, and the piston rod 2-1 on the piston 2 in the cylinder 1 is opposite to the push rod 12-1 in the medicine core 12; then the gas source is connected to the air inlet 4 of the gas storage chamber 5, and compressed gas begins to be introduced into the gas storage chamber 5. When the pressure of the gas in the gas storage chamber 5 rises to a predetermined firing pressure, it will overcome the elastic force of the spring, and the gas in the gas storage chamber 5 will instantly rush into the rodless chamber 1-2 from the air flow channel 6, so that the piston 2 is quickly fired forward, and the piston rod 2-1 pushes the push rod 12-1 to eject the liquid medicine in the medicine core 12 at a high speed in a thinner liquid stream, instantly penetrating the skin to reach the subcutaneous tissue, and completing the injection;

After the injection is completed, the gas source is cut off, the piston 2 is automatically reset under the action of the spring, and the sealing member 7 on the piston 2 is pressed against the lower surface of the energy storage plug 9 again; the next injection can be carried out after the drug core 12 is replaced;

Due to the difference in epidermal thickness of different injection targets, for example, when vaccinating different types of pets, the required firing pressures are not the same; therefore, it is worth noting that in this embodiment, different firing pressures can be obtained by replacing springs of different specifications, and the piston chamber 1-1 in the cylinder 1 also provides sufficient installation space for the spring.

In this embodiment, the energy storage plug 9 and the seal 7 are sealed in the form of a planar contact, which can adapt to relatively small firing pressures. However, when the firing pressure is relatively large, the sealing performance between the energy storage plug 9 and the seal 7 of this sealing structure will show disadvantages, and the gas in the gas energy storage chamber 5 may leak from the air flow channel 6 to the rodless chamber 1-2 in advance, causing the piston 2 to be injected at a firing pressure lower than the predetermined pressure, which may easily lead to the inability of the drug solution to penetrate the epidermis.

Example 2

As shown in Figure 2, the difference between Example 2 and Example 1 is that: a sealing protrusion 9-1 extends downward from the lower surface of the energy storage plug 9, the air flow channel 6 passes through the sealing protrusion 9-1, and the head assembly is provided with a one-way mechanism allowing gas to enter the gas energy storage chamber 5 from the rodless chamber 1-2;.

The outer peripheral surface of the sealing protrusion 9-1 is a conical surface with a larger upper end and a smaller lower end.

The one-way mechanism includes a one-way gasket 10 and a one-way spring 11. The energy storage plug 9 is penetrated by an exhaust hole 9-2. One end of the one-way spring 11 is against the head 8 or the energy storage plug 9, and the other end is against the one-way gasket 10. The one-way gasket 10 is against the energy storage plug 9 at the upper end of the exhaust hole 9-2. In this embodiment, the one-way gasket 10 can be specifically selected from rubber pads.

The working principle of this embodiment is the same as that of the embodiment 1, but there is a difference in the sealing structure between the piston 2 and the sealing member 7, so as to enable the piston 2 to perform precise injection at a larger predetermined firing pressure. The specific analysis is as follows:

When the piston 2 is reset, the sealing protrusion 9-1 can pre-press against the sealing member 7 to block the airflow channel 6. Due to the setting of the one-way mechanism, the piston 2 can continue to move toward the energy storage plug 9 to reset, and the gas in the rodless chamber 1-2 will be discharged to the gas energy storage chamber 5 through the exhaust hole 9-2. Since the contact area between the sealing member 7 and the sealing protrusion 9-1 is small, the sealing performance is better, thereby ensuring that the piston 2 can perform precise injection at a larger predetermined firing pressure.

Example 3

As shown in Figure 3, the difference between Example 3 and Example 2 is that: an air storage groove 9-4 is opened on the lower surface of the energy storage plug 9, and the sealing protrusion 9-1 is located in the air storage groove 9-4; or an air storage groove is opened on the upper surface of the piston 2; the purpose is as follows: even if there is a slight leakage between the sealing protrusion 9-1 and the seal 7, due to the existence of the air storage groove 9-4, the leaked gas will enter the air storage groove 9-4, so the pressure of the rodless chamber 1-2 will be less affected before firing, and the firing pressure can be more accurately controlled.

Example 4

As shown in Figure 5, the difference between Example 4 and Examples 1 and 2 is that: an upper protrusion 7-1 extends upward from the upper surface of the sealing member 7, a sealing groove 9-3 matching the upper protrusion 7-1 is opened at the lower end of the airflow channel 6, and the upper protrusion 7-1 is embedded in the sealing groove 9-3. Specifically, the upper protrusion 7-1 is a conical structure with a small upper end and a large lower end.

The working principle of this embodiment is the same as that of the embodiment 1, but there is a difference in the sealing structure between the piston 2 and the sealing member 7, so that the piston 2 can perform accurate injection at a moderate predetermined firing pressure. The specific analysis is as follows:

When the piston 2 is reset, the upper protrusion 7 - 1 of the sealing member 7 will be embedded and clamped into the sealing groove 9 - 3 of the energy storage plug 9 , and the sealing effect on the airflow channel 6 is relatively good.

The above-mentioned ideal embodiments of the present invention are for inspiration. Through the above-mentioned description, relevant staff can make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims (7)

1. A drug delivery device, characterized in that it comprises a barrel (1) having a piston chamber (1-1), a piston (2), a head assembly and an elastic element (3), wherein the piston (2) is slidably disposed in the piston chamber (1-1), the head assembly and the elastic element (3) are respectively arranged at two ends of the piston (2), and the head assembly has an air inlet (4), a gas energy storage chamber (5) and an air flow channel (6) which are interconnected, and the air inlet (4) is used to allow gas from a gas source to pass into the gas energy storage chamber (5); The portion of the piston chamber (1-1) between the piston (2) and the head assembly is a rodless chamber (1-2); a sealing member (7) is provided between the piston (2) and the head assembly; the elastic element (3) causes the piston (2) to abut against the head assembly, so that the sealing member (7) blocks the air flow passage (6) of the gas energy storage chamber (5); when the gas in the gas energy storage chamber (5) is stored to a point where its pressure overcomes the elastic force of the elastic element (3), the piston (2) is fired, and the air flow passage (6) is connected to the rodless chamber (1-2); The end cap assembly comprises an end cap (8) and an energy storage plug (9), wherein the end cap (8) is fixedly mounted on the upper end of the cylinder (1), and the energy storage plug (9) is fixed on the end cap (8) and forms the gas energy storage chamber (5) between the end cap and the end cap (8); The air flow channel (6) passes through the lower surface of the energy storage plug (9), the sealing member (7) is fixed on the piston (2), and the lower surface of the energy storage plug (9) is opposite to the sealing member (7); A sealing protrusion (9-1) extends downward from the lower surface of the energy storage plug (9), the air flow channel (6) passes through the sealing protrusion (9-1), and the head assembly is provided with a one-way mechanism that allows gas to enter the gas energy storage chamber (5) from the rodless chamber (1-2); The one-way mechanism comprises a one-way gasket (10) and a one-way spring (11); the energy storage plug (9) is penetrated by an exhaust hole (9-2); one end of the one-way spring (11) abuts against the end cap (8) or the energy storage plug (9), and the other end abuts against the one-way gasket (10); the one-way gasket (10) abuts against a portion of the energy storage plug (9) located above the exhaust hole (9-2); When the piston (2) is reset, the sealing protrusion (9-1) abuts against the sealing member (7) in advance to block the air flow channel (6), and the piston (2) can continue to move toward the energy storage plug (9) to reset, and the gas in the rodless chamber (1-2) is discharged to the gas energy storage chamber (5) through the exhaust hole (9-2). 2. The drug delivery device according to claim 1, characterized in that: an air storage groove (9-4) is provided on the lower surface of the energy storage plug (9), and the sealing protrusion (9-1) is located in the air storage groove (9-4); or an air storage groove is provided on the upper surface of the piston (2). 3. The drug delivery device according to claim 1, characterized in that the outer peripheral surface of the sealing protrusion (9-1) is a conical surface with a larger upper end and a smaller lower end. 4. The drug delivery device according to claim 1, characterized in that: a mounting groove (2-2) is provided on the upper surface of the piston (2), and the sealing member (7) is embedded in the mounting groove (2-2). 5. The drug delivery device according to claim 1, characterized in that: an upper protrusion (7-1) extends upward from the upper surface of the sealing member (7), a sealing groove (9-3) matching the upper protrusion (7-1) is formed at the lower end of the air flow channel (6), and the upper protrusion (7-1) is embedded in the sealing groove (9-3). 6. The drug delivery device according to claim 1, characterized in that: the elastic element (3) is a spring, one end of the elastic element (3) abuts against the inside of the cylinder (1), and the other end abuts against the piston (2), and the elastic element (3) is sleeved outside the piston rod (2-1) of the piston (2). 7. The drug delivery device according to claim 1, characterized in that the sealing element (7) is a rubber pad.