CN115463288A

CN115463288A - Needleless injector

Info

Publication number: CN115463288A
Application number: CN202211090990.3A
Authority: CN
Inventors: 张明
Original assignee: Beijing Qs Medical Technology Co ltd
Current assignee: Beijing Qs Medical Technology Co ltd
Priority date: 2022-09-07
Filing date: 2022-09-07
Publication date: 2022-12-13

Abstract

The invention relates to a needleless injector, which comprises an injection assembly and an actuating assembly. The injection assembly comprises an injection cavity shell and a piston assembly, the injection cavity shell surrounds an injection cavity, and the front end of the injection cavity shell is provided with injection micropores communicated with the outside and the injection cavity. The piston assembly is arranged in the injection cavity, the piston assembly can move in the injection cavity along a first direction facing the injection micro-hole and a second direction opposite to the first direction, and a passage communicated with the injection cavity is arranged in the piston assembly. The actuation assembly comprises an operating device movable in a first direction and a transmission device capable of converting a movement of the operating device in the first direction into a movement of the injection plunger in a second direction. The needleless injector according to the scheme can simplify the operation of a user.

Description

Needleless injector

Technical Field

The present invention relates to a medical device for injecting a liquid drug. More particularly, the present invention relates to a needleless injector.

Background

The needleless injector does not need to use a needle, but is a medical device for injecting a liquid medicine into the subcutaneous space of a patient through micropores in the end part by applying high pressure to the liquid medicine, thereby being capable of preventing the patient from suffering from acupuncture.

Needleless injectors typically include a syringe and a plunger disposed within the syringe. When it is intended to add a medical fluid to a syringe, the user is typically required to pull the piston in a direction away from the injector head, and when it is intended to perform an injection operation, the user is required to push the piston in a direction towards the injector head. As can be seen, the conventional needleless injector has more steps and is more complicated to operate by a user.

Accordingly, there is a need to provide a needleless injector that at least partially addresses the above problems.

Disclosure of Invention

In order to overcome the above drawbacks, the present invention proposes a needleless injector that is capable of simplifying the operations of the user, making the operations of the user more labor-saving, and that has a simple structure and is easy to manufacture and assemble.

According to one aspect of the present invention, there is provided a needleless injector comprising:

an injection assembly, comprising:

the injection cavity shell surrounds an injection cavity, and the front end of the injection cavity shell is provided with an injection micropore for communicating the outside and the injection cavity;

a piston assembly disposed in the injection chamber, the piston assembly being configured to be movable in the injection chamber in a first direction toward the injection micro-hole and a second direction opposite to the first direction, the piston assembly having a passage provided therein that communicates with the injection chamber;

an actuation assembly comprising:

an operating device configured to be movable in the first direction;

a transmission configured to convert movement of the operating device in the first direction into movement of the injection plunger in the second direction.

In one embodiment, the needle-free injector further comprises a ram assembly comprising an injection ram connected to and configured to move synchronously with the piston assembly.

In one embodiment, the operating device is cylindrical and has an open end and a closed end, the push rod assembly being arranged inside the operating device via the open end.

In one embodiment, the needleless injector further comprises a housing portion disposed between the operation device and the push rod assembly, the housing portion being connected to the injection cavity housing, the transmission device being at least partially disposed on the housing portion.

In one embodiment, the transmission device comprises a gear disposed on the housing portion, the operating device is provided inside with a first rack disposed along an axial direction of the injection plunger, the plunger assembly is provided with a second rack disposed along the axial direction of the injection plunger, and the gear is engaged with the first rack and the second rack, respectively.

In one embodiment, the transmission means comprises a roller wheel provided on the housing portion and a belt engaged with the roller wheel, one end of the belt being connected to the operating means and the other end being connected to the push rod assembly.

In one embodiment, the transmission device includes a sprocket and a chain engaged with the sprocket, the sprocket being disposed on the housing portion, one end of the chain being connected to the operating device and the other end being connected to the push rod assembly.

In one embodiment, the needleless injector further comprises:

a drug storage assembly disposed radially inward of the injection plunger, comprising:

a drug storage cavity housing enclosing a drug storage cavity configured to be communicable with the passageway;

a plug movably disposed in the drug storage chamber;

a drug delivery push rod movably disposed in the drug storage chamber, the drug delivery push rod disposed at an end of the plug distal from the injection micro-hole, the drug delivery push rod having a first end and a second end opposite to the first end, the first end configured to act on the plug.

In one embodiment, the actuation assembly further comprises an actuation device configured to actuate the administration pushrod in a predetermined state, the administration pushrod configured to push the plug in the first direction when actuated such that the medical fluid in the reservoir chamber is pushed into the injection chamber via the passageway.

In one embodiment, the drug storage assembly is movable relative to the injection ram between an initial position and an activated position, wherein the drug storage cavity is distal from the piston assembly when the drug storage assembly is in the initial position and the drug storage cavity is engaged with the piston assembly and in communication with the passageway when the drug storage assembly is in the activated position.

In one embodiment, a safety device is further included, the safety device being operably disposed between the drug storage chamber and the injection chamber, the safety device being configured to restrain the drug storage assembly in the initial position when not operated, and the drug storage assembly being movable to the activated position when the safety device is operated.

In one embodiment, the safety feature is at least partially removably disposed between the drug storage chamber and the injection chamber, the safety feature being configured to enable communication between the drug storage chamber and the injection chamber when at least partially removed.

In one embodiment, the safety device is rotatably disposed between the drug storage chamber and the injection chamber, the safety device being configured to enable communication between the drug storage chamber and the injection chamber upon being rotated.

In one embodiment, the safety device is movably disposed between the drug storage chamber and the injection chamber, the safety device being configured to enable communication between the drug storage chamber and the injection chamber upon being moved and then rotated.

In one embodiment, the safety device is movably disposed between the reservoir and the injection chamber, the safety device being configured to enable communication between the reservoir and the injection chamber upon being rotated and then moved.

In one embodiment, the medicine storage assembly further comprises a first elastic member, the injection push rod is configured in a cylindrical shape, the first elastic member is arranged inside the injection push rod, one end of the first elastic member acts on the injection push rod, the other end of the first elastic member can act on the medicine storage assembly, and when the medicine storage assembly is in the initial position, the first elastic member is in a compressed state.

In one embodiment, the housing portion and the injection plunger are provided with corresponding first and second insertion slots, respectively, and the safety device is configured to be inserted through the first and second insertion slots and to be blocked between the piston assembly and the drug storage chamber when the safety device is inserted into the first and second insertion slots.

In one embodiment, the injection plunger is configured to move with the plunger assembly between a first position proximate the injection wells and a second position distal the injection wells.

In one embodiment, the plunger assembly further comprises a locking device configured to lock the injection plunger with the locking device during movement of the injection plunger from the first position to the second position in the second direction, and to unlock the injection plunger from the locking device when the injection plunger reaches the second position.

In one embodiment, the locking device includes a locking sleeve sleeved outside the injection plunger and disposed inside the housing portion, the locking sleeve has a flange portion protruding inward in a radial direction thereof, the injection plunger is provided with a stepped portion, the flange portion is engaged with the stepped portion, the locking member is disposed at an outer periphery of the injection plunger, when the injection plunger is locked, the locking member protrudes from the outer periphery of the injection plunger and is located at an end of the flange portion away from the injection micro-hole, and a projection of the locking member on a plane perpendicular to a central axis of the injection plunger and a projection of the flange portion on the plane have an overlapping portion.

In one embodiment, when the injection plunger is in the second position, the locking element is movable in a radial direction towards the centre axis of the administration plunger, and a projection of the locking element onto the plane does not overlap a projection of the flange portion onto the plane.

In one embodiment, a portion of the administration rod adjacent the second end is provided with a first recess recessed radially inwardly, the locking element being received in the first recess when the injection rod is in the second position.

In one embodiment, when the injection plunger is in the second position, the lock moves with the injection plunger to a second end that extends beyond the administration plunger in the second direction.

In one embodiment, the needle-free injector further comprises a drive device configured to drive the injection plunger to move in the first direction when the injection plunger is unlocked.

In one embodiment, the drive means is configured as a second spring, both ends of which are capable of acting on the injection plunger and the locking sleeve, respectively, the second spring being in a compressed state when the injection plunger is in the second position.

In one embodiment, the actuator comprises a rotating part engaged with the administration push rod and a nut part, the rotating part can drive the administration push rod to rotate, the administration push rod is provided with an external thread section, and the external thread section is in threaded engagement with an internal thread of the nut part.

In one embodiment, the nut portion is disposed inside the injection plunger, and a stopper member configured to restrict rotation of the nut portion relative to the injection plunger is disposed between the nut portion and the injection plunger.

In one embodiment, the housing part is arranged inside the operating device via the open end, the closed end is provided with an inner helical structure inside, and one end of the rotary part has an outer helical structure, which engages in the inner helical structure.

In one embodiment, the end of the housing part close to the closed end has a first support edge projecting radially inwards, on which the rotary part can be supported.

In one embodiment, the rotary part has a second support edge extending radially outwards, and a bearing is arranged between the second support edge and the first support edge.

In one embodiment, the first elastic member is sleeved outside the drug delivery push rod, the other end of the first elastic member can act on the nut portion, a flange extending outwards along the radial direction of the drug delivery push rod is further arranged on the drug delivery push rod, and the nut portion can abut against the flange at one end far away from the injection micropore.

In one embodiment, the actuating means comprises a pushing portion disposed outside the administration push rod and engaged inside the injection push rod, the first end of the administration push rod being provided with a stop flange protruding radially outwards, and a third resilient member having both ends acting on the stop flange and the pushing portion, respectively.

In one embodiment, the push portion is configured to move with the drug storage assembly between the initial position and the activated position relative to the injection plunger, the administration plunger being locked relative to the push portion when the drug storage assembly is in the initial position, the third resilient member being in a compressed state, the administration plunger being unlocked relative to the push portion when the drug storage assembly is in the activated position.

In one embodiment, the actuating device further comprises a locking member disposed at an outer periphery of the pushing portion, and the administration push rod is provided with a second recess recessed radially inward, and the locking member is received in the second recess when the drug storage assembly is in the initial position.

In one embodiment, the injection plunger has a first receptacle and a second receptacle therein, the first receptacle having a larger cross-sectional area than the second receptacle, the drug storage chamber being disposed in the first receptacle, the locking member being located in the second receptacle and being confined between the administration plunger and the injection plunger in a radial direction of the administration plunger when the drug storage assembly is in the initial position, the pushing portion and the locking member moving into the first receptacle during movement of the drug storage assembly from the initial position to the activated position to allow the locking member to move radially outward.

In one embodiment, the piston assembly includes a piston and a piston pusher connected to the piston, a forward end of the piston pusher engaging the piston, the passageway including a first passageway disposed in the piston and a second passageway disposed in the piston pusher.

In one embodiment, an end of the piston rod distal to the injection micro-hole is provided with a tubular piercing member in communication with the second passage, the drug storage assembly comprises a drug storage plug provided at an end of the drug storage chamber housing, and the piercing member is configured to pierce the drug storage plug when the drug storage assembly is moved to the activation position.

In one embodiment, the locking element is a sphere or a cylinder extending perpendicular to the axis of the injection plunger.

The needle-free injector according to the preferred embodiment of the present invention is provided with a transmission device, wherein the transmission device can convert the movement of the operating device along the first direction into the movement of the piston assembly along the second direction, so that the user only needs to press the operating device along the direction towards the injection micropore to move the piston assembly in the injection cavity away from the injection micropore, thereby making room for the liquid medicine and facilitating the subsequent high-pressure triggering of the liquid medicine for injection operation. The scheme can simplify the operation of a user, so that the user operation is more labor-saving, and the structure is simple, and the manufacture and the assembly are convenient.

Drawings

For a better understanding of the above and other objects, features, advantages and functions of the invention, reference should be made to the preferred embodiments illustrated in the accompanying drawings. The same or similar reference numbers in the drawings refer to the same or similar parts. It will be appreciated by persons skilled in the art that the drawings are intended to illustrate preferred embodiments of the invention without any limiting effect on the scope of the invention, and that the various components in the drawings are not drawn to scale.

Fig. 1 shows a perspective view of a needle-free injector according to a first preferred embodiment of the invention in a cutaway condition;

FIGS. 2-6 are sectional views of the needleless injector according to the first preferred embodiment of the present invention in different operating states, respectively, wherein FIGS. 2-6 illustrate the operation of the needleless injector in sequence;

fig. 7 shows a perspective view of a needle-free injector according to a second preferred embodiment of the present invention in a cutaway state;

fig. 8-12 are sectional views, respectively, of a needle-free injector according to a second preferred embodiment of the present invention in different operating states, wherein fig. 8-12 show the operation of the needle-free injector in sequence;

FIGS. 13 and 14 show sectional views of a needleless injector in accordance with a third preferred embodiment of the present invention in different operating states, respectively; and

fig. 15 shows a cross-sectional view of a needleless injector in accordance with a fourth preferred embodiment of the present invention.

Detailed Description

Hereinafter, a needleless injector according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The following is given only by way of preferred embodiments according to the invention, on the basis of which other ways of implementing the invention may be conceived by those skilled in the art, which also fall within the scope of the invention.

First, it should be noted that the term "front" as used herein refers to a direction in which a liquid medicine is pushed out when the needleless syringe is used, that is, a direction toward a site to be injected, and a direction opposite thereto is referred to as "rear".

Embodiment mode 1

Fig. 1 shows a schematic view of a needleless injector according to a first preferred embodiment of the present invention in an initial state. Fig. 2-6 are sectional views of the needleless injector according to the first preferred embodiment of the present invention in different operation states, respectively, wherein fig. 2-6 illustrate the operation of the needleless injector in sequence.

Referring first to fig. 1, in one embodiment, a needle-free injector 100 generally comprises an injection assembly 101, a drug storage assembly 102, and an actuation assembly 103. An injection assembly 101 is located at the forward end of the needle-free injector 100. The injection assembly 101 includes an injection chamber housing 104 and a piston assembly 105 disposed in the injection chamber housing 104. The injection chamber housing 104 is configured in a cylindrical shape, which encloses an injection chamber. The injection chamber housing 104 has injection micro-holes 106 at the front end thereof for communicating the outside with the injection chamber. When an injection operation is intended, the injection chamber housing 104 may be pressed against a site to be injected, for example, the skin of a patient, and when an injection operation (described below) is triggered, a medical fluid in the injection chamber may be injected into the patient through the injection micro-holes 106.

The piston assembly 105 is movably arranged in the injection chamber, in particular the piston assembly 105 is movable in the injection chamber in a first direction towards the injection micro holes 106 and in a second direction opposite to the first direction. A passageway is provided in the piston assembly 105 that communicates with the injection chamber.

In a preferred embodiment, the piston assembly 105 includes a piston 107 and a piston pusher 108 connected to the piston 107, a front end of the piston pusher 108 engaging the piston 107. The front end of the piston 107 is configured as a cone, and the front end of the injection cavity has a shape matching the cone-shaped front end of the piston. The conical tip is inserted into the injection micro-hole 106, and the rear end of the piston 107 has a groove portion to be engaged with the front portion of the piston rod 108. In the illustrated embodiment, the front end of the piston rod 108 is engaged with the piston 107 by a snap structure 109, and it will be understood that in other embodiments not shown, the piston rod 108 and the piston 107 may be engaged by other means such as screw engagement or adhesion.

The piston 107 has a first passage 110 provided therein, the first passage 110 being arranged at an angle to the central axis of the injection chamber in the preferred embodiment shown, it being understood that the first passage 110 may be arranged parallel to the central axis of the injection chamber in other embodiments not shown. The piston pusher 108 has a second passage 111 provided therein, the second passage 111 preferably extending in the direction of the central axis of the injection chamber. Preferably, the first passage 110 and the second passage 111 are spaced apart in the radial direction of the injection cavity. The first passage 110 and the second passage 111 together form the passage described above. The rear end of the piston rod 108, i.e. the end remote from the injection micro-hole 106, is provided with a tubular piercing member 112, the piercing member 112 is in communication with the second passage 111, and the piercing member 112 can be used to pierce a drug storage plug 113 (described below) of the drug storage chamber.

As shown in fig. 2 and 3, the drug storage assembly 102 includes a drug storage chamber housing 114, a plug 115, and a drug delivery pushrod 116. The drug storage chamber housing 114 encloses a drug storage chamber in which a drug solution to be injected can be pre-stored. The front end of the drug storage chamber housing 114 has a drug storage plug 113, and the drug storage plug 113 can be pierced by the piercing member 112 when the drug storage assembly 102 is moved to an activated position (described below) to place the drug storage chamber in communication with the passageway of the piston assembly. The plug 115 may preferably be a rubber plug that is movably disposed in the drug storage chamber and has an outer diameter that matches the inner diameter of the drug storage chamber. A drug delivery push rod 116 is movably disposed in the drug storage chamber, the drug delivery push rod 116 is disposed at an end of the plug 115 distal from the injection micro-holes 106, and the drug delivery push rod 116 can push the plug 115 in a direction toward the injection micro-holes 106. The administration push rod 116 has a first end provided with a radially outwardly protruding stop flange 117 and a second end opposite the first end, which may act on the plug 115.

In a preferred embodiment, as shown in fig. 1, the needle-free injector 100 further comprises a push rod assembly comprising an injection push rod 118, wherein the injection push rod 118 is sleeve-shaped and is sleeved on the radial outer side of the drug storage cavity housing 114, that is, the injection push rod 118 has a hollow structure, and the drug storage cavity housing 114 is arranged inside the injection push rod 118. The forward end of the injection ram 118 is connected with the piston ram 108, and the injection ram 118 is capable of moving synchronously with the piston assembly 105. Illustratively, the injection ram 118 may be coupled to the piston ram 108 by a snap-fit connection, a threaded connection, or the like.

In a preferred embodiment, with continued reference to fig. 1, the needleless injector 100 further includes a housing portion 119, the housing portion 119 being generally cylindrical and disposed about the injection plunger 118. Preferably, the housing portion 119 is threaded to the injection chamber housing 104. It will be appreciated that in other embodiments not shown, the housing portion 119 may be connected to the injection chamber housing 104 in other ways as well.

In a preferred embodiment, the drug reservoir assembly 102 is movable between an initial position and an activated position relative to the injection ram 118. Wherein when the drug storage assembly 102 is in the initial position, the drug storage chamber is distal from the piston assembly 105 and the drug storage chamber is not in communication with the passageway in the piston assembly 105, as shown in figures 1 and 2. When the drug storage assembly 102 is in the activated position, as shown in figure 3, the drug storage assembly 102 is moved to a position adjacent to the piston assembly 105 and the drug storage chamber is engaged with the piston assembly 105, the piercing member 112 of the piston ram 108 pierces the drug storage plug 113 at the forward end of the drug storage chamber so that the drug storage chamber is in communication with the passageway.

Needleless injector 100 further includes a safety 120, safety 120 being operatively disposed between the drug reservoir and the injection chamber. When the safety device is operated, the medicine storage cavity can be communicated with the injection cavity. The safety 120 is capable of blocking the combination of the drug storage chamber and the injection chamber when the safety 120 is not operated, and may also prevent the action of an operating means 128 (described below). Therefore, the safety device can prevent the medicine storage cavity from being combined with the injection cavity by the structural characteristics of the safety device, and the locking is realized. In a preferred embodiment, a safety 120 is at least partially removably disposed between the drug storage chamber and the injection chamber, the safety being configured to enable communication between the drug storage chamber and the injection chamber when at least partially removed. As shown in fig. 2, in the illustrated embodiment, the safety 120 is integrally removably disposed between the drug storage chamber and the piston assembly 105. When the safety 120 is disposed between the drug storage chamber and the piston assembly 105, it acts to block the movement of the drug storage assembly 102 and to restrain the drug storage assembly 102 in the initial position. As shown in fig. 3, the drug storage assembly 102 is movable to the activated position when the safety 120 is removed from between the drug storage chamber and the piston assembly 105. In the illustrated embodiment, the safety 120 is removed entirely to allow communication between the drug storage chamber and the injection chamber. In other embodiments not shown, a safety feature may also be partially removably disposed between the drug storage chamber and the injection chamber.

In other embodiments, not shown, the unlocking can also be performed by changing the structural features of the safety device in other operating modes. For example:

in a preferred embodiment, a safety device is rotatably disposed between the drug storage chamber and the injection chamber, the safety device being configured to enable communication between the drug storage chamber and the injection chamber upon being rotated.

In another preferred embodiment, a safety device is movably disposed between the reservoir chamber and the injection chamber, the safety device being configured to enable communication between the reservoir chamber and the injection chamber upon being moved and then rotated, or the safety device being further configured to enable communication between the reservoir chamber and the injection chamber upon being rotated and then moved.

In a preferred embodiment, the housing 119 is provided with a first insertion groove 121 opened along a radial direction thereof, and the injection plunger 118 is provided with a second insertion groove 122 opened along a radial direction thereof, wherein positions of the first insertion groove 121 and the second insertion groove 122 correspond when the injection plunger 118 is in a first position (described below). The safety 120 includes a grip portion 123 and a holding plate 124 connected to the grip portion 123, the holding plate 124 being configured to be inserted between the piston assembly 105 and the medicine storage chamber via the first and

second insertion grooves

121 and 122, and the grip portion 123 being convenient for a user to hold. The retainer plate 124 of the safety 120 is insertable between the piston assembly 105 and the medicine storage chamber through the first and

second insertion grooves

121 and 122, and the retainer plate 124 is caught between the piston assembly 105 and the medicine storage chamber when the safety 120 is inserted into the first and

second insertion grooves

121 and 122. As shown in fig. 2, the retaining plate 124 has a thickness in the axial direction of the injection chamber so that the piston assembly 105 and the drug storage chamber can be spaced apart by a certain distance. When it is intended to insert the safety 120 into the first and

second insertion grooves

121 and 122 or to take out the safety 120 from the first and

second insertion grooves

121 and 122, it is possible to perform an operation by gripping the grip portion 123.

In addition, the safety device 120 also serves to lock the injection plunger 118 and the housing 119 relative to each other, thereby preventing relative displacement therebetween.

With continued reference to fig. 2 and 3, the drug storage assembly 102 further includes a first resilient member 125, the first resilient member 125 being disposed within the injection ram 118. As shown in fig. 2, an end of the interior of the injection ram 118 remote from the second insertion slot 122 is provided with a ring of radially inwardly extending stop flanges 126, and one end of the first resilient member 125 acts on the stop flanges 126, e.g., the first resilient member 125 may engage the stop flanges 126 and the other end may act on the drug storage assembly 102 (described in detail below). As shown in fig. 2, the first resilient member 125 is in a compressed state when the drug storage assembly 102 is in an initial position, i.e., when the safety 120 is blocked between the drug storage assembly 102 and the piston assembly 105. When the safety 120 is removed, the drug storage assembly 102 may move to the activated position under the restoring force of the first resilient member 125, as shown in figure 3, since there is no interference between the drug storage assembly 102 and the piston assembly 105. In the illustrated embodiment, the first elastic member 125 is configured as a spring and is sleeved on the exterior of the administration push rod 116. It is understood that in other embodiments not shown, the first elastic member 125 may be configured as an air bag or other structure.

The actuation assembly 103 can push the administration push rod 116 in a direction toward the injection micro-holes 106 in a predetermined state to push the medical fluid in the drug storage chamber into the injection chamber, and can pull the piston assembly 105 in a direction away from the injection micro-holes 106 to empty the space of the injection chamber for the medical fluid to enter into the injection chamber. The structure of the actuation assembly 103 is described in detail below.

The actuation assembly 103 comprises an actuation means 127, an operating means 128 and a transmission means 129. As shown in fig. 1-6, the operating device 128 is cylindrical, has a hollow structure, and has an open end 130 and a closed end 131. The housing portion 119 and the injection plunger 118 and the drug reservoir assembly etc. therein are fitted inside the operating means 128 via the open end 130. The operating means 128 is operable by a user, in particular the operating means 128 is depressible by the user in a first direction towards the site to be injected.

A transmission 129 is preferably provided on the housing portion 119 between the operating device 128 and the injection plunger 118, the transmission 129 being configured to convert a movement of the operating device 128 in a first direction into a movement of the injection plunger 118 in a second direction, which is opposite to the first direction. That is, the injection ram 118 may be moved in the second direction synchronously as the operating device 128 moves in the first direction. Since the injection plunger 118 is coupled to the piston assembly 105, when the injection plunger 118 moves in the second direction, the piston plunger 108 may move in the second direction along with the injection plunger 118, thereby freeing up space in the injection cavity. The structure of the transmission 129 will be described in further detail later.

The actuation means 127 is configured to actuate the administration push rod 116 in a predetermined state, preferably when the operating means 128 is pressed. When the operating means 128 is pressed, the administration push rod 116 is actuated, thereby pushing the stopper 115 in a first direction towards the injection micro-hole 106, such that the medical fluid in the reservoir is pushed into the injection chamber via the passageway.

In a preferred embodiment, the injection plunger 118 is configured to move with the piston assembly 105 between a first position proximate to the injection micro-bore 106 and a second position distal to the injection micro-bore 106. Wherein the injection ram 118 is movable from a first position to a second position when the operating means 128 is operated, and from the second position to the first position under the drive of a drive means 132 (described below). Fig. 2 and 3 illustrate the injection ram 118 and piston assembly 105 in a first position, in which the piston assembly 105 is abutting the forward end of the injection chamber housing 104. FIG. 4 illustrates the movement of the injection ram 118 and piston assembly 105 from the first position to the second position, with the injection ram 118 and piston assembly 105 in an intermediate position between the first position and the second position. FIG. 5 shows the injection ram 118 and piston assembly 105 in a second position. FIG. 6 shows injection ram 118 and piston assembly 105 triggered to return to the first position from the second position.

Preferably, the ram assembly further comprises a locking device configured to maintain the injection ram 118 in a locked state during movement of the injection ram 118 in the second direction from the first position to the second position, wherein movement in the first direction is restricted when the injection ram 118 is in the locked state. This arrangement allows the injection plunger 118 to remain in its current position throughout its movement, while preventing it from returning to its first position upon actuation of the drive means 132 (described below). Furthermore, the locking device can be automatically unlocked when the injection plunger 118 reaches the second position, thereby unlocking the injection plunger 118 from the locking device, so that the injection plunger 118 can be returned to the first position by the driving device 132.

As shown in fig. 1-6, in a preferred embodiment, the locking device includes a locking sleeve 133 and a locking member 134. The locking sleeve 133 is disposed outside the injection plunger 118 and inside the housing 119, and the locking sleeve 133 is provided with a flange 135 protruding radially inwardly, and correspondingly, the injection plunger 118 is provided with a step 136. Flange portion 135 engages with step 136, and when injection plunger 118 is moved in a second direction from a first position to a second position, step 136 may push flange portion 135 so that the lockout device may move with injection plunger 118.

A locking piece 134 is provided at the outer circumference of the injection plunger 118 at the rear end of the stepped portion 136. As shown in fig. 2 to 4, when the injection plunger 118 is locked with respect to the locking device, the locking member 134 protrudes from the outer circumference of the injection plunger 118 and is located at the rear end of the flange portion 135, i.e., the end away from the injection micro-hole 106, and a projection of the locking member 134 on a plane perpendicular to the central axis of the injection plunger 118 has an overlapping portion with a projection of the flange portion 135 on the plane. This arrangement enables the flange portion 135 to block the locking member 134 from moving in the first direction, and thus can block the injection plunger 118 from moving in the first direction toward the front end. The locking member 134 is preferably a ball, for example, at least two balls may be evenly arranged circumferentially. Alternatively, the locking element 134 may be a cylinder that extends perpendicular to the central axis of the injection ram 118.

In a preferred embodiment, the portion of the administration push rod 116 adjacent the second end is provided with a first recess 137 recessed radially inwardly, the first recess 137 allowing the locking member 134 to be received therein. When the injection plunger 118 is in the second position, as shown in fig. 5, the locking element 134 is able to move radially inward, i.e. towards the central axis of the administration plunger 116, into the first recess 137, and when the locking element 134 moves radially inward into the first recess 137, the projection of the locking element 134 onto the above-mentioned plane does not overlap with the projection of the flange portion 135 onto the above-mentioned plane, so that the flange portion 135 no longer blocks the locking element 134, thereby unlocking the injection plunger 118 and allowing the injection plunger 118 to return to the first position in the first direction under the driving of the driving means 132.

As shown in fig. 2-6, the driving device 132 is preferably configured as a second spring, which is sleeved on the outside of the injection push rod 118, and the injection push rod 118 is provided with a blocking edge 138 extending radially outward along the second insertion groove 122, and the blocking edge 138 forms a groove wall of the second insertion groove 122 at the same time. One end of the second spring abuts against the locking sleeve 133 and the other end abuts against the blocking edge 138 (see fig. 4). When the injection plunger 118 is in the second position, the second spring is in a compressed state, such that when the injection plunger 118 is unlocked relative to the locking device, the injection plunger 118 may return to the first position in the first direction under the restoring force of the second spring.

As shown in fig. 2-6, in one embodiment, the transmission 129 includes a gear 139, the gear 139 being disposed on the housing portion 119. The inner wall of the operating device 128 is provided with a first rack 140 arranged in its axial direction, the axial direction of the operating device 128 coinciding with the axial direction of the injection plunger 118, the outer wall of the locking sleeve 133 is provided with a second rack 141 arranged in its axial direction, the axial direction of the locking sleeve 133 coinciding with the axial direction of the injection plunger 118. The gear 139 is engaged with the first rack 140 and the second rack 141, respectively. When the operating means 128 is pressed in the first direction, the locking sleeve 133, together with the injection ram 118 and the piston assembly 105, may be moved in the second direction by the same distance as the operating means 128, by the rotation and transmission of the gear 139. The direction of movement of the operating means 128 and thus the locking sleeve 133 is indicated by arrows in fig. 4. It will be appreciated that in other embodiments not shown, a person skilled in the art may use a double gear or bevel gear or other similar means to control the proportional relationship between the distance the operating device 128 is depressed and the distance the injection ram 118 is moved in the opposite direction.

Preferably, the transmission 129 may include two gears symmetrically disposed about a central axis of the housing portion 119, and accordingly, the number of the first and second racks corresponds to the number of the gears.

With continued reference to fig. 2-6, the actuation means 127 comprises a rotation part 142, the rotation part 142 having a hollow structure, the second end of the administration push rod 116 being engageable in the hollow structure of the rotation part 142. Preferably, the second end of the administration pushrod 116 has a non-circular shape, such as square or triangular, and the hollow structure has a shape that fits the second end of the administration pushrod 116 such that the rotation part 142 can rotate in synchronization with the administration pushrod 116. The rotating portion 142 has an outer spiral structure 143 at a rear end thereof, and the operating device 128 has a closed end 131 internally provided with an inner spiral structure 144, the outer spiral structure 143 being engaged in the inner spiral structure 144. When the operating device 128 is axially pressed in the first direction, the rotating part 142 can be rotated by the screw engagement of the outer screw structure 143 and the inner screw structure 144, so that the administration feeding rod 116 can be rotated along with the rotating part 142.

In a preferred embodiment, the administration push rod 116 has an externally threaded section 145 thereon, and the actuation means 127 further comprises a nut portion 146 threadedly engaged on the externally threaded section 145. The nut portion 146 is disposed inside the injection plunger 118 and at one end of the administration plunger 116. Preferably, a stopper member (not shown) is disposed between the nut portion 146 and the injection push rod 118, and may be, for example, a male-female fit structure disposed on an outer surface of the nut portion 146 and an inner surface of the injection push rod 118, respectively, and configured to restrict rotation of the nut portion 146 relative to the injection push rod 118.

In a preferred embodiment, the thread of the rotation portion 142 is opposite to the thread of the externally threaded section 145 of the administration feeding rod 116. This arrangement enables the administration pushrod 116 to rotate with the rotating portion 142 when the operating means 128 is axially pressed in the first direction, while the administration pushrod 116 is axially moved in the first direction by the nut portion 146 to push the plug 115 and thus push the medical fluid in the drug storage chamber into the injection chamber via the passageway in the piston assembly 105.

In a preferred embodiment, the thread lead of the administration pushrod 116 and the thread lead of the rotating portion 142 are determined by the ratio of the inner cross-sectional area of the injection lumen to the inner cross-sectional area of the drug storage lumen. It should be noted that the inner cross-sectional areas of the injection chamber and the drug storage chamber mentioned herein are the inner cross-sectional areas of the main body portions of the injection chamber and the drug storage chamber. It is further preferred that the ratio of the thread lead of rotating portion 142 to the thread lead of administration pushrod 116 is equal to the ratio of the cross-sectional area of the drug storage chamber to the cross-sectional area of the injection chamber. When the cross-sectional area within the syringe chamber is equal to the cross-sectional area within the drug reservoir, the thread lead of rotary portion 142 is equal to the thread lead of administration pushrod 116. When the injection chamber has a smaller cross-sectional area than the drug reservoir, the thread lead of rotating portion 142 is greater than the thread lead of administration pushrod 116. When the injection chamber has a larger cross-sectional area than the drug reservoir, the thread lead of rotating portion 142 is less than the thread lead of administration pushrod 116.

In a preferred embodiment, the end of the housing portion 119 adjacent the closed end 131, i.e. the rear end of the housing portion 119, is provided with a ring of first support edges 147 extending radially inwardly therealong, and the rotary portion 142 has second support edges 148 extending radially outwardly therealong. Preferably, a bearing 149 is provided between the second support side 148 and the first support side 147, so that friction between the rotation part 142 and the housing part 119 can be reduced and the rotation operation of the rotation part 142 can be smoother. Preferably, the bearing 149 is a flat thrust bearing.

In one embodiment, the first elastic element 125 is sleeved outside the drug delivery push rod 116, and the other end of the first elastic element can act on the nut portion 146, and the nut portion 146 abuts against the drug storage chamber housing 114. The administration push rod 116 is further provided with a flange 150 extending radially outwardly therefrom, and in the initial position of the drug storage assembly 102, the nut portion 146 abuts against the flange 150 at an end remote from the injection micro-hole 106, and the flange 150 is configured as an end point of an end of the external thread section 145, and functions to prevent the nut portion 146 from being disengaged from the external thread section 145. During movement of the drug storage assembly 102 from the initial position to the activated position, the restoring force of the first resilient member 125 acts on the nut portion 146, causing the nut portion 146 to move in the first direction, pushing the drug storage chamber housing 114 and the flange 150 of the administration push rod 116, such that the drug storage assembly 102 as a whole may move in the first direction.

The use of the needleless injector 100 will be discussed in detail below in conjunction with fig. 2-6, sequentially.

Fig. 2 shows the needleless injector 100 in an initial state. Typically, when the needle-free injector 100 is not in use by a user, the needle-free injector 100 is in the condition shown in fig. 2. In this state, the safety device 120 blocks the drug storage chamber from the plunger rod 108 of the injection chamber. The first elastic member 125 and the second spring are in a compressed state at this time.

Fig. 3 shows a state where the safety 120 is removed. In this state, the nut portion 146 is pushed by the elastic force of the first elastic member 125, thereby transmitting the pushing force to the medicine storage assembly 102, so that the medicine storage assembly 102 moves relative to the injection push rod 118, engaging with the piston push rod 108. The needle-pricked component on the piston push rod 108 pierces the medicine storage plug 113 at the end of the medicine storage cavity to conduct the medicine liquid in the medicine storage cavity and the passage of the piston push rod 108. The medical fluid may be delivered to the junction of the piston ram 108 and the piston 107 via the second passageway of the piston ram 108. Since the piston 107 is now at the front end inside the injection chamber housing 104, there is no deformation space, so that the medical fluid does not enter the injection chamber through the first passage on the piston 107.

Fig. 4 shows the needleless injector 100 in a state in which the operating device 128 is being pressed but is not pressed in place. During this process, the operator presses the forward end of the injection chamber housing 104 against the skin of the injection site, pressing the actuation device 128, and moving the actuation device 128 in a direction towards the injection site. During depression of the operating means 128, rotation of the gear 139 causes the assembly of the injection ram 118, the piston assembly 105 and the locking means to move in a direction away from the injection site.

Meanwhile, during the pressing of the operating device 128, the inner screw structure of the operating device 128 interacts with the outer screw structure of the rotating part 142, thereby rotating the rotating part 142. The rotator 142 transfers rotational motion to the administration pushrod 116. By the relative rotation of the administration push rod 116 and the nut portion 146, the administration push rod 116 pushes the stopper 115 in the drug storage chamber in the first direction, pushing a predetermined volume of the drug solution out of the drug storage chamber. The liquid medicine is replenished to the joint of the piston 107 and the piston rod 108 through the second passage 111 in the piston rod 108. The inner surface of the piston 107 is deformed by the pressure of the medical fluid, so that the medical fluid is introduced into the injection chamber through the first passage 110 of the piston 107. The end of the injection cavity is pressed against the skin of the injection part, and the injection micropores 106 are sealed, so that the liquid medicine cannot flow out of the inner part of the injection cavity.

Fig. 5 shows the state of the needle-less injector 100 when the operating device 128 is pressed to a predetermined position. When the operating means 128 is pressed to a predetermined position, the administration push rod 116 has pushed the stopper 115 inside the drug storage chamber to a set position to expel a set volume of drug solution. It will be appreciated that the set position of the administration push rod 116 determines the dose injected. When the administration push rod 116 is moved to the set position, the injection push rod 118 is moved to the second position, the first recess 137 on the administration push rod 116 coincides with the path of movement of the locking element 134 on the injection push rod 118, such that the locking element 134 may be moved radially inward into the first recess 137 in the direction of the central axis of the administration push rod 116, thereby unlocking the locking means from engagement with the injection push rod 118.

After the locking device is unlocked from engagement with the injection ram 118, the injection ram 118 and the piston ram 108 engaged therewith are movable from the second position to the first position under the drive of the drive device 132.

Fig. 6 shows the needle-free injector 100 with the injection ram 118 and piston ram 108 engaged therewith returning from the second position to the first position under the drive of the drive device 132 (i.e., second spring). In the process, the second spring pushes the injection plunger 118 and the piston plunger 108 to move, and the injection pushing force is transmitted to the liquid medicine in the injection cavity through the piston 107. The liquid medicine is injected into the body of the patient through the injection micropores 106 at the end of the injection cavity. After the administration push rod 116 is moved to the proper position, the administration push rod 116 no longer pushes the stopper 115 inside the drug storage chamber, and thus the drug solution is no longer delivered to the inside of the injection chamber. The elastic deformation of the piston 107 is restored to seal the path for the liquid medicine transfer. In the injection process, as the surface of the piston 107 in the injection cavity is subjected to the pressure of the liquid medicine, the joint surface of the piston 107 and the piston push rod 108 is pressed tightly, and the liquid medicine can be prevented from flowing back to the piston push rod 108.

The needleless injector according to the preferred embodiment of the present invention is provided with a transmission 129, which can convert the movement of the operation device 128 along the first direction into the movement of the piston assembly 105 along the second direction, so that the user can move the piston assembly 105 in the injection cavity away from the injection micro-hole 106 in the injection cavity by only pressing the operation device 128 along the direction towards the injection micro-hole 106, thereby making room for the liquid medicine and facilitating the subsequent high-pressure triggering of the liquid medicine for the injection operation. The scheme can simplify the operation of a user, so that the user operation is more labor-saving, and the structure is simple, and the manufacture and the assembly are convenient.

Embodiment mode 2

Hereinafter, the needle-less injector 200 according to the second preferred embodiment of the present invention will be described in detail with reference to fig. 7 to 12. The needle-free injector 200 according to the second preferred embodiment has substantially the same structure as the needle-free injector 100 according to the first preferred embodiment except for the structure of the actuating means, and therefore, for the sake of brevity, only the differences will be described in detail herein.

As shown in fig. 7, in a preferred embodiment, the actuating means 227 comprises a pushing portion 251 and a third elastic member 252. The third elastic member 252 is disposed at the outer periphery of the administration push rod 216. The first end of the administration push rod 216 is provided with a stopper flange 217 protruding radially outward, and one end of the third elastic member 252 abuts against the stopper flange 217. The pushing portion 251 is preferably configured as a sleeve, which is disposed inside the injection push rod 218 and sleeved outside the administration push rod 216, and the other end of the third elastic member 252 abuts against the front end of the pushing portion 251. One end of the first elastic member 225 abuts against the stop flange 226 and the other end abuts against the rear end of the pushing part 251, so that the pushing part 251 can move together with the medicine storage assembly 202 from the initial position to the activated position under the force of the first elastic member 225. When the drug storage assembly 202 is in the initial position shown in fig. 8, the third resilient member 252 is in a compressed state and the first resilient member 225 is in a compressed state. The third elastic member 252 is preferably a spring, and is fitted over the outside of the administration push rod 216. It is understood that in other embodiments not shown, the third elastic member 252 may be configured as a balloon or other structure.

It can be understood that, when the third elastic member 252 is in a compressed state, an elastic force is applied to the stopper flanges 217 and the push portions 251 at both ends thereof. In order to avoid displacement of the administration push rod 216 and the push portion 251 under spring force when the drug storage assembly 202 is in the initial position, in particular to avoid the administration push rod 216 pushing the plug 215 in the first direction under spring force, preferably, the actuation means 227 further comprises a locking member 260, the locking member 260 being capable of locking the administration push rod 216 relative to the push portion 251 when the drug storage assembly 202 is in the initial position and of unlocking the administration push rod 216 relative to the push portion 251 when the drug storage assembly 202 is in the activated position. Further, the front end of the pushing portion 251 further includes a first stopper portion 261 protruding outward in a radial direction thereof, and accordingly, a stepped portion forming a second stopper portion 262 is provided inside the injection plunger 218, the second stopper portion 262 divides the inside of the injection plunger 218 into at least a first accommodating portion 263 and a second accommodating portion 264, and a cross-sectional area of the first accommodating portion 263 is larger than a cross-sectional area of the second accommodating portion 264. The first stopping portion 261 and the second stopping portion 262 cooperate to block the pushing portion 251 from moving in the second direction under the action of the elastic force. The drug storage assembly 202 is disposed in the first receiving portion 263.

The locking member 260 is disposed on the outer periphery of the pushing portion 251, the administration push rod 216 is provided with a second concave portion 265 which is recessed radially inward, when the medicine storage assembly 202 is in the initial position, the locking member 260 is located in the second accommodating portion 264, and is restricted between the second concave portion 265 of the administration push rod 216 and the injection push rod 218 in the radial direction of the administration push rod 216, and abuts on the rear end surface of the second concave portion 265, so that the administration push rod 216 can be restricted from being displaced in the first direction by the elastic force of the third elastic member 252. During the movement of the drug storage assembly 202 from the initial position to the activated position, the pushing portion 251 and the locking member 260 move into the first receiving portion 263, allowing the locking member 260 to move radially outward since the cross-sectional area of the first receiving portion 263 is larger than the cross-sectional area of the second receiving portion 264. When the locking member 260 moves radially outward, it may no longer abut on the rear end surface of the second recess 265, so that the lock of the administration push rod 216 may be released, so that it may be displaced in the first direction by the elastic force of the third elastic member 252. The locking elements 260 are preferably balls, for example, at least two balls may be evenly circumferentially arranged. Alternatively, the locking member 260 may be a cylinder extending along a central axis perpendicular to the pushing portion 251.

Further, in the present embodiment, unlike the first embodiment, the portion of the administration push rod 216 near the second end does not have the first recess 137. When the injection plunger 218 is in the second position, the locking member 234 moves with the injection plunger 218 to a position extending beyond the second end of the administration plunger 216 in the second direction, leaving a vacant area inside the excess portion of the injection plunger 218, allowing the locking member 234 to move radially inward to the vacant area, thereby unlocking the injection plunger 218 and allowing the injection plunger 218 to return to the first position in the first direction under the drive of the drive means 232.

The use of the needleless injector 200 will now be described briefly in sequence with reference to fig. 8-12. This use is substantially the same as the use of needleless injector 100.

Fig. 8 shows the needleless injector 200 in an initial state. The needleless injector 200 is normally in the state shown in fig. 8 when the user is not using the needleless injector 200. In this state, the safety device 220 blocks the drug storage chamber from the plunger rod 208 of the injection chamber. The first elastic member 225 and the second spring are in a compressed state at this time.

Fig. 9 shows a state where the safety device 220 is removed. In this state, the pushing portion 251 is pushed by the elastic force of the first elastic member 225, thereby transmitting the pushing force to the medicine storage assembly 202, so that the medicine storage assembly 202 moves relative to the injection plunger 218, engaging with the piston plunger 208. The needle-prick component on the piston push rod 108 pierces the medicine storage plug 213 at the end of the medicine storage cavity to conduct the medicine liquid in the medicine storage cavity and the passage of the piston push rod 208. The medical fluid may be delivered to the junction of the piston pusher 208 and the piston 207 via the passageway of the piston pusher 208. Since the piston 207 is now at the front end of the interior of the injection chamber housing 204, there is no deformation space, so that the medical fluid does not enter the injection chamber through the first passage 210 of the piston 207.

Fig. 10 shows the needleless injector 200 in a state in which the operation device 228 is being pressed but is not pressed in place. In the process, the operator presses the distal end of the injection chamber housing 204 against the skin of the injection site, and presses the actuator 228, thereby moving the actuator 228 in a direction toward the injection site. During depression of the operating means 228, rotation of the gear 239 causes the assembly of the injection ram 218, the piston assembly 205 and the locking means to move away from the injection site.

Meanwhile, when the elastic force applied to the administration push rod 216 by the third elastic member 252 is greater than the frictional force between the administration push rod 216 and the pushing part 251 during the pressing of the operating means 228, the administration push rod 216 moves in the first direction, pushes the stopper 215 in the drug storage chamber, and pushes a predetermined volume of the drug solution out of the drug storage chamber. The liquid medicine is replenished to the joint of the piston 207 and the piston push rod 208 through the second passage 211 in the piston push rod 208. The inner surface of the piston 207 is deformed by the pressure of the medical fluid, so that the medical fluid is introduced into the injection chamber through the first passage 210 of the piston 207. Since the end of the injection cavity is pressed against the skin of the injection site and the injection micropores 206 are sealed, the medical liquid does not flow out from the inside of the injection cavity.

Fig. 11 shows the state of the needle-less injector 200 when the operating device 228 is pressed to a predetermined position. When the operating means 228 is depressed to a predetermined position, the administration push rod 216 has pushed the stopper 215 inside the drug storage chamber to a set position to expel a set volume of drug solution. When the administration push rod 216 is moved to the set position, the injection push rod 218 is moved to the second position and the locking member 234 is moved radially inward to the vacant area, thereby unlocking the locking device from engagement with the injection push rod 218.

After the locking device is unlocked from engagement with the injection ram 218, the injection ram 218 and the piston ram 208 engaged therewith are movable from the second position to the first position by the drive device 232.

Fig. 12 shows the needleless injector 200 with the injection ram 218 and the plunger ram 208 engaged therewith returned to the first position from the second position under the drive of the drive device 232 (i.e., the second spring). In the process, the second spring pushes the injection plunger 218 and the piston plunger 208 to move, and the injection pushing force is transmitted to the liquid medicine in the injection cavity through the piston 207. The liquid medicine is injected into the body of the patient through the injection micro-holes 206 at the end of the injection cavity. After the drug delivery pushrod 216 moves to the proper position, the drug delivery pushrod 216 no longer pushes the stopper 215 inside the drug storage chamber, and thus the drug solution is no longer delivered to the inside of the injection chamber. The elastic deformation of the piston 207 is restored to seal the passage for the liquid medicine transfer. In the injection process, the surface of the piston 207 in the injection cavity is subjected to the pressure of the liquid medicine, so that the joint surface of the piston 207 and the piston push rod 208 is pressed tightly, and the liquid medicine can be prevented from flowing back to the piston push rod 208.

Embodiment 3

A needle-less injector 300 according to a third preferred embodiment of the present invention will be described in detail with reference to fig. 13-14. Except for the structure of the transmission, the needle free injector 300 according to the third preferred embodiment has substantially the same structure as the needle free injector 100 according to the first preferred embodiment, and therefore, for the sake of brevity, only the differences will be described in detail herein.

Fig. 13 illustrates the needleless injector 300 when the drug storage assembly 302 is in the initial position. In this embodiment, the transmission device 329 includes a roller 371 and a belt 372 engaged with the roller 371, the roller 371 is disposed on the housing portion 319, a first end of the belt 372 is connected to the operating device 328 and is capable of moving in a first direction along with the operating device 328, and a second end of the belt 372 is connected to the locking sleeve 333, such that when the operating device 328 moves in the first direction, as shown in fig. 14, the first end of the belt 372 is capable of driving the roller 371 to rotate, such that the second end of the belt 372 can drive the locking sleeve 333 to move along with the injection push rod 318 in a second direction opposite to the first direction.

In other embodiments, not shown, the transmission device may further comprise a sprocket wheel and a chain engaging with the sprocket wheel, the sprocket wheel being arranged on the housing part, one end of the chain being connected to the operating device and the other end being connected to the locking sleeve.

Embodiment 4

A needleless injector 400 in accordance with a fourth preferred embodiment of the present invention will be described in detail with reference to fig. 15. The needleless injector 400 according to the fourth preferred embodiment has substantially the same structure as the injector 100 according to the first preferred embodiment except for the structure of the driving means, and therefore, only the differences will be described in detail herein for the sake of brevity.

In the present embodiment, the cavity between the housing portion 419 and the injection plunger 418 is sealed, and the gas in the cavity can be compressed and accumulated. In order to ensure the tightness of the cavity, a first sealing ring 481 and a second sealing ring 482 are arranged at intervals in the axial direction of the injection plunger 418, the first sealing ring 481 and the second sealing ring 482 are respectively arranged around the injection plunger 418 between the injection plunger 418 and the housing part 419, the first sealing ring 481 abuts against the front end of the injection plunger 418, that is, the end close to the injection micro-holes 406, and the second sealing ring 482 abuts against the locking sleeve 433. When the injection ram 418 is in the second position, gas between the housing portion 419 and the injection ram 418 is compressed and stored. Thus, when injection ram 418 is unlocked, it may be moved from the second position to the first position under the urging of compressed gas.

The foregoing description of various embodiments of the invention is provided for the purpose of illustration to one of ordinary skill in the relevant art. It is not intended that the invention be limited to a single disclosed embodiment. As above, many alternatives and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the above teachings. Thus, while some alternative embodiments are specifically described, other embodiments will be apparent to, or relatively easily developed by, those of ordinary skill in the art. The present invention is intended to embrace all such alternatives, modifications and variances of the present invention described herein, as well as other embodiments that fall within the spirit and scope of the present invention as described above.

Claims

1. A needleless injector, comprising:

an injection assembly (101) comprising:

the injection cavity shell (104) encloses an injection cavity, and the front end of the injection cavity shell (104) is provided with an injection micropore (106) which is communicated with the outside and the injection cavity;

a piston assembly (105) disposed in the injection chamber, the piston assembly being configured to be movable in the injection chamber in a first direction toward the injection micro-hole and a second direction opposite to the first direction, a passage being disposed in the piston assembly (105) in communication with the injection chamber; and

an actuation assembly (103) comprising:

an operating device (128), the operating device (128) being configured to be movable along the first direction;

a transmission (129), the transmission (129) being configured to convert movement of the operating device (128) in the first direction into movement of the piston assembly in the second direction.

2. The needle free injector of claim 1, further comprising a housing portion (119), the housing portion (119) being connected to the injection cavity housing (104), the transmission (129) being at least partially disposed on the housing portion (119), the needle free injector further comprising a ram assembly comprising an injection ram (118) connected to the piston assembly (105) and configured to move synchronously with the piston assembly (105).

3. The needle free injector according to claim 2, characterized in that the transmission means (129) comprises a gear wheel (139), the gear wheel (139) being provided on the housing part (119), the operating means (128) being provided with a first rack (140) arranged in the axial direction of the injection plunger (118), the plunger assembly being provided with a second rack (141) arranged in the axial direction of the injection plunger (118), the gear wheel (139) being in engagement with the first rack (140) and the second rack (141), respectively.

4. The needle free injector of claim 2, wherein the transmission (329) comprises a roller (371) and a strap (372) engaged with the roller, the roller being disposed on the housing portion (319), the strap being connected at one end to the operating device (328) and at the other end to the push rod assembly.

5. The needle free injector of claim 2, wherein the transmission means (129) comprises a sprocket wheel provided on the housing portion (119) and a chain engaged with the sprocket wheel, one end of the chain being connected to the operating means (128) and the other end being connected to the push rod assembly.

6. The needle free injector of claim 2, wherein the operating device is cylindrical and has an open end (130) and a closed end (131), the plunger assembly being disposed inside the operating device via the open end.

7. The needle free injector of claim 6, further comprising:

a drug storage assembly (102) disposed radially inward of the injection plunger, comprising:

a drug storage chamber housing (114) enclosing a drug storage chamber configured to be communicable with the passageway;

a plug (115) movably disposed in the drug storage chamber;

a drug delivery pushrod (116) movably disposed in the drug storage chamber, the drug delivery pushrod (116) disposed at an end of the plug (115) distal from the injection orifice (106), the drug delivery pushrod (116) having a first end and a second end opposite the first end, the first end configured to act on the plug (115).

8. The needle free injector of claim 7, wherein the actuation assembly (103) further comprises an actuation device (127), the actuation device (127) being configured to actuate the administration pushrod (116) in a predetermined state, the administration pushrod (116) being configured to push the plug (115) in the first direction when actuated such that medical fluid in the reservoir is pushed into the injection chamber via the passageway.

9. The needle free injector of claim 8, wherein the drug storage assembly (102) is movable relative to the injection plunger (118) between an initial position and an activated position, wherein the drug reservoir is distal from the piston assembly (105) when the drug storage assembly (102) is in the initial position and the drug reservoir is engaged with the piston assembly (105) and in communication with the passageway when the drug storage assembly (102) is in the activated position.

10. The needle free injector of claim 9, further comprising a safety (120), the safety (120) operably disposed between the drug reservoir and the injection chamber, the safety configured to define the drug reservoir assembly (102) in the initial position when not operated, and the drug reservoir assembly (102) movable to the activated position when the safety (120) is operated.

11. The needle free injector of claim 10, wherein the safety feature (120) is at least partially removably disposed between the drug reservoir and the injection chamber, the safety feature being configured to enable communication between the drug reservoir and the injection chamber when at least partially removed.

12. The needle free injector of claim 10, wherein the safety is rotatably disposed between the drug reservoir and the injection chamber, the safety being configured to enable communication between the drug reservoir and the injection chamber when rotated.

13. The needle free injector of claim 10, wherein the safety is movably disposed between the reservoir and the injection chamber, the safety being configured to enable communication between the reservoir and the injection chamber upon being moved and then rotated.

14. The needle free injector of claim 10, wherein the safety device is movably disposed between the reservoir and the injection chamber, the safety device being configured to enable communication between the reservoir and the injection chamber upon being rotated and then moved.

15. The needle free injector according to claim 9, wherein the drug storage assembly (102) further comprises a first elastic member (125), the injection plunger (118) is configured as a cylinder, the first elastic member (125) is disposed inside the injection plunger (118), one end of the first elastic member (125) acts on the injection plunger (118) and the other end can act on the drug storage assembly (102), and when the drug storage assembly (102) is in the initial position, the first elastic member (125) is in a compressed state.

16. The needle free injector according to claim 10, wherein the housing portion (119) and the injection plunger (118) are provided with corresponding first and second insertion slots (121, 122), respectively, the safety device (120) being configured to be insertable via the first and second insertion slots (121, 122), the safety device (120) being blocked between the piston assembly (105) and the drug reservoir when the safety device (120) is inserted into the first and second insertion slots (121, 122).

17. The needle free injector of claim 2, wherein the injection plunger (118) is configured to move with the piston assembly (105) between a first position proximate the injection orifice (106) and a second position distal the injection orifice (106).

18. The needle free injector of claim 17, wherein the ram assembly further comprises a locking device configured to retain the injection ram (118) in a locked state during movement of the injection ram (118) from the first position to the second position and to unlock the injection ram (118) when the injection ram (118) reaches the second position, wherein the injection ram is restricted from moving in the first direction when in the locked state.

19. The needle free injector according to claim 18, wherein the locking device comprises a locking sleeve (133) and a locking piece (134), the locking sleeve (133) is sleeved outside the injection plunger (118) and is arranged inside the housing part (119), the locking sleeve (133) has a flange part (135) protruding radially inward along the locking sleeve, the locking piece (134) is arranged on the outer circumference of the injection plunger (118), when the injection plunger (118) is locked, the locking piece (134) protrudes from the outer circumference of the injection plunger (118) and is located at one end of the flange part (135) away from the injection micro hole (106), and a projection of the locking piece (134) on a plane perpendicular to a central axis of the injection plunger (118) has an overlapping portion with a projection of the flange part (135) on the plane.

20. The needle free injector according to claim 19, wherein the lock (134) is radially movable towards the central axis of the administration rod (116) when the injection plunger (118) is in the second position, and a projection of the lock (134) onto the plane does not overlap a projection of the flange portion (135) onto the plane.

21. The needle free injector of claim 20, wherein a portion of the administration rod (116) proximate the second end is provided with a first recess (137) recessed radially inward, the lock (134) being received in the first recess (137) when the injection rod (118) is in the second position.

22. The needle free injector of claim 20, wherein the lock (234) moves with the injection plunger (218) to a second end extending beyond the administration plunger (216) in the second direction when the injection plunger (218) is in the second position.

23. The needle free injector of claim 19, further comprising a drive device (132), the drive device (132) configured to drive the injection ram (118) to move in the first direction when the injection ram (118) is unlocked.

24. The needle free injector according to claim 23, wherein the drive means (132) is configured as a second spring having both ends capable of acting on the injection plunger (118) and the locking sleeve (133), respectively, the second spring being in a compressed state when the injection plunger (118) is in the second position.

25. The needle free injector according to claim 15, wherein the actuating device (127) comprises a rotating part (142) engageable with the administration rod (116) and a nut part (146), the rotating part (142) being capable of rotating the administration rod (116), the administration rod (116) having an external threaded section (145) thereon, the external threaded section (145) being in threaded engagement with the internal thread of the nut part (146).

26. The needle free injector of claim 25, wherein the nut portion (146) is disposed inside the injection plunger (118) and a stop member is disposed between the nut portion (146) and the injection plunger (118) and is configured to limit rotation of the nut portion (146) relative to the injection plunger (118).

27. A needleless injector according to claim 25, wherein the housing part (119) is arranged inside the operation device (128) via the open end, the closed end is internally provided with an internal helical structure (144), and one end of the rotary part (142) has an external helical structure (143) in which the external helical structure engages.

28. The needle-free injector according to claim 25, wherein the first elastic member (125) is fitted over the administration push rod (116) and the other end is capable of acting on the nut portion (146), the administration push rod (116) is further provided with a flange extending radially outward therefrom, and the nut portion (146) is capable of abutting against the flange at an end away from the injection micro-hole (106).

29. The needle free injector according to claim 9, wherein the actuation means (127) comprises a pushing portion (251) and a third resilient member (252), the pushing portion (251) being arranged outside the administration rod (216) and engaging inside the injection rod (218), the first end of the administration rod (216) being provided with a stop flange (217) protruding radially outwards, both ends of the third resilient member (252) acting to the stop flange (217) and the pushing portion (251), respectively.

30. The needle free injector of claim 29, wherein the push portion (251) is configured to move with the drug storage assembly (202) relative to the injection ram (218) between the initial position and the activated position, the administration ram (216) being locked relative to the push portion (251) when the drug storage assembly (202) is in the initial position, the third resilient member (252) being in a compressed state, the administration ram (216) being unlocked relative to the push portion (251) when the drug storage assembly (202) is in the activated position.

31. The needle free injector of claim 30, wherein the actuation means (127) further comprises a latch (260) disposed at an outer periphery of the push portion (251), the administration rod (116) being provided with a second recess (265) recessed radially inward, the latch being received in the second recess when the drug storage assembly (102) is in the initial position.

32. The needle free injector of claim 31, wherein the injection plunger (118) has a first receptacle (263) and a second receptacle (264) therein, the first receptacle (263) having a larger cross-sectional area than the second receptacle (264), the drug reservoir being disposed in the first receptacle (263), the locking member (260) being located in the second receptacle (264) and being confined between the administration plunger (116) and the injection plunger (118) in a radial direction of the administration plunger (116) when the drug reservoir assembly (102) is in the initial position, the pushing member (251) and the locking member moving into the first receptacle (263) during movement of the drug reservoir assembly (102) from the initial position to the activated position to allow the locking member (260) to move radially outward.

33. The needle free injector of claim 19, wherein the lock (134) is a sphere or a cylinder extending perpendicular to the axis of the injection ram (118).