Quantitative dosing device

Abstract

The utility model provides a quantitative dosing device which comprises a dosing cylinder, a piston and a piston rod. The piston slides in the dosing cylinder in a sealing manner, and one end of the piston rod extends into the dosing cylinder and is fixedly connected with the piston; the outer wall of the piston rod is provided with at least one row of clamping groove sets, and each row of clamping groove sets comprises a plurality of clamping grooves evenly distributed in the axial direction of the piston rod. A clamping jaw matched with the clamping groove is arranged on the administration cylinder; when the piston rod moves in the dosing direction relative to the dosing cylinder, the clamping jaws enter different clamping grooves in the same row of clamping groove sets under pushing of the piston rod. The quantitative dosing device is simple to operate, and can quickly and accurately control the single-time pushing dosage, and the dosing efficiency and the dosing accuracy are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of medical devices, and particularly relates to a quantitative medicine dispenser. Background Art

[0002] In the medical field, some special patients, such as diabetic patients, often need to inject insulin in multiple fixed doses for drug treatment. At present, the method of administering medicine in multiple fixed doses is mainly realized by a syringe with scales. When using, the user needs to carefully check the scales each time of injection to avoid the problem of excessive or insufficient injection. This process has relatively high requirements for the user and it is not easy to achieve the precision of each injection. Summary of the Utility Model

[0003] In view of the above-mentioned disadvantages of the prior art, the purpose of the present utility model is to provide a quantitative medicine dispenser that is simple to use and convenient to operate, which can quickly and accurately control the single-push dose, and improve the medicine administration efficiency and precision.

[0004] To achieve the above purpose and other related purposes, the present utility model provides a quantitative medicine dispenser, which includes a medicine administration cylinder, a piston and a piston rod; the piston is hermetically and slidably arranged in the medicine administration cylinder, and one end of the piston rod extends into the medicine administration cylinder and is fixedly connected with the piston; at least one row of card slot groups is arranged on the outer wall of the piston rod, and each row of card slot groups includes a plurality of card slots uniformly arranged along the axial direction of the piston rod; a claw is arranged on the medicine administration cylinder and is matched with the card slots; when the piston rod moves relative to the medicine administration cylinder in the medicine administration direction, the claw is pushed by the piston rod and enters different card slots in the same row of card slot groups; thus, when the claw is located in a card slot of the piston rod and the inner side wall of the card slot far away from the piston contacts the claw, the claw will axially limit the piston rod, so that the piston rod cannot move in the medicine administration direction under the action of a small external force; when medicine administration is required, a large external force can be applied to the piston rod to make it move in the medicine administration direction. At this time, the claw will rotate away from the piston rod under the push of the card slot to exit the corresponding card slot, and the piston rod will continue to move in the medicine administration direction. The claw will insert into the adjacent card slot again and produce a "click" sound to remind the operator to push the piston rod with a smaller external force until the claw contacts the inner side wall of the adjacent card slot far away from the piston to complete the quantitative medicine administration work for this time; since the whole medicine administration process does not need to be observed, as long as the operator senses the difficulty of pushing the piston rod, it can be determined whether the piston rod is pushed in place, which has the advantages of simple operation and convenient use.

[0005] Preferably, a plurality of rows of slot groups are provided on the outer wall of the piston rod; the slots in different rows of slot groups have different sizes in the axial direction of the piston rod, or the slots in different rows of slot groups have different arrangement spacings; in this way, the dosage of the quantitative drug delivery device can be switched by simply rotating the piston rod to switch the cooperation between the slot groups and the claws in different rows of the piston rod, thereby meeting the drug delivery requirements of different people.

[0006] Preferably, an outer flange is formed at the open end of the dosing barrel; a gripping piece is detachably provided on the outer flange, and a through hole is provided on the gripping piece for movement of the piston rod; the claw is provided on the gripping piece, and the claw and the gripping piece are integrally formed; the claw and the gripping piece are integrally formed, which facilitates the rapid disassembly and assembly of the quantitative dosing device.

[0007] Preferably, the gripping piece includes a main body portion, and a flange slot that is plug-in-matched with the outer flange is provided on the side wall of the main body portion; a first through hole is provided on the main body portion for axial movement of the piston rod, and the first through hole is connected to the side wall of the main body portion where the flange slot is provided to form a first opening structure, so that the gripping piece can be installed on the dosing barrel in an insert-fit manner, thereby reducing the difficulty of disassembly and assembly of the gripping piece; in addition, since the first through hole limits the rotation of the piston rod, it is effectively prevented that the piston rod rotates during the dosing process and affects the accuracy of the dosing dose.

[0008] Preferably, a clamp portion is formed on the main body portion, and the clamp portion is used to clamp the drug cartridge to ensure the installation stability of the gripping member.

[0009] Preferably, the claw is located at an end of the main body away from the clamp portion.

[0010] Preferably, a guide portion is formed at one end of the main body away from the clamp portion; a second through hole is provided on the guide portion for axial movement of the piston rod, and the second through hole is connected to the outer wall of the guide portion to form a second opening structure; the opening direction of the second opening structure is consistent with the insertion direction of the flange slot; the utility model guides the axial movement of the piston rod by the guide portion, thereby further ensuring the stability of the axial movement of the piston rod.

[0011] Preferably, a stopper is formed on the guide portion; the stopper is arranged at the second opening structure to prevent the piston rod from escaping from the second through hole.

[0012] Preferably, the stopper comprises a first guide surface; when the piston rod moves into the second through hole, the first guide surface of the stopper is squeezed to make the stopper rotate toward the second through hole, thereby facilitating the piston rod to smoothly move into the second through hole.

[0013] Preferably, the integrally formed part formed by the claw and the gripping member is made of plastic or metal with resilience, which has the advantage of low cost.

[0014] As mentioned above, a quantitative dosing device of the utility model has the following beneficial effects:

[0015] 1) Before quantitative administration, the claw is located in a slot of the piston rod, and the inner wall of the slot away from the piston contacts the claw. At this time, the claw will axially limit the piston rod, so that the piston rod cannot move in the administration direction under the action of a small external force; when quantitative administration is performed, a large external force must be applied first to move the piston rod in the administration direction. During this process, the claw will rotate in the direction away from the piston rod to exit the current slot and insert into the adjacent slot; when the claw is inserted into the adjacent slot, a "click" sound will be generated to remind the operator to use a small external force to push the piston rod until the claw contacts the inner wall of the adjacent slot away from the piston and cannot move further. At this point, a single quantitative administration is completed; since the movement stroke of the piston rod is fixed each time the drug is administered, the accuracy of the dosage is effectively guaranteed; in addition, there is no need for naked eye observation during the entire administration process. It only needs to sense the difficulty of pushing the piston rod to determine whether the piston rod is pushed in place, which has the advantages of simple operation and easy use.

[0016] 2) When the piston rod is provided with multiple rows of slot groups, the operator only needs to rotate the piston rod to make the slot group of the required dose correspond to the claw, thereby satisfying multiple fixed-dose dosing for different dosing requirements.

[0017] 3) The claw and the gripping piece are integrally formed, and the gripping piece is arranged on the outer flange of the dosing barrel in an insert-type manner, which effectively reduces the difficulty of assembling the quantitative dosing device; in addition, since the gripping piece includes a guide portion and a stop portion arranged at the second opening structure of the guide portion, when the piston rod enters the second through hole in the piston rod through the second opening structure, the stop portion can limit the piston rod from disengaging from the second through hole, thereby ensuring the installation stability; and the second through hole can effectively limit the rotation of the piston rod, thereby preventing the piston rod from rotating during the dosing process and affecting the accuracy of the dosing dose. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A three-dimensional diagram of a dosing device.

[0019] Figure 2 It is a vertical cross-sectional view of the dosing device.

[0020] Figure 3 It is a left side view of the integrally formed part of the gripping part and the claw.

[0021] Figure 4 It is a front view of the integrally formed part of the gripper and the claw.

[0022] Figure 5 for Figure 4 AA isometric section view.

[0023] Figure 6 A cross-sectional view of the piston rod and the grasping member in one embodiment.

[0024] Figure 7 A cross-sectional view of the piston rod and the grasping member in another embodiment.

[0025] Explanation of reference numerals

[0026] Drug cartridge 1, outer flange 11, piston 2, piston rod 3, pressing head 31, card slot 41, claw 42, cantilever 421, hook 422, grasping member 5, main body 51, flange slot 51a, first through hole 51b, second through hole 53a, clamping portion 52, limiting block 521, guiding portion 53, axial support 531, intermediate connector 532, stop portion 54, first guiding surface 541. Detailed implementation manners

[0027] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0028] Please refer to Figures 1 to 7 . It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have any technical essence. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear description and are not used to limit the scope under which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0029] The present invention provides a metered dispenser that can supply liquid medicine in multiple fixed doses; as Figure 1 and Figure 2As shown, the metered dose dispenser includes a medicine delivery cylinder 1, a piston 2 and a piston rod 3. One end of the medicine delivery cylinder 1 is an open end, and the other end of the medicine delivery cylinder 1 is a liquid medicine inlet / outlet end. The piston 2 axially slides in the medicine delivery cylinder 1 in a sealed manner, and one end of the piston rod 3 extends into the medicine delivery cylinder 1 and is fixedly connected to the piston 2. Thus, by simply pushing or pulling the piston rod 3, the liquid medicine can be inhaled into or discharged from the medicine delivery cylinder 1. At least one row of card slot groups is provided on the outer wall of the piston rod 3, and each row of card slot groups includes a plurality of card slots 41 evenly arranged along the axial direction of the piston rod 3, and the sizes of the card slots 41 in the same row of card slot groups are the same. A pawl 42 is provided on the medicine delivery cylinder 1 and is engaged with the card slot 41. When the piston rod 3 moves relative to the medicine delivery cylinder 1 in the medicine delivery direction (i.e., the direction close to the liquid medicine inlet / outlet end), the pawl 42 will sequentially enter different card slots 41 in the same row of card slot groups under the push of the piston rod 3. Since the distance between two adjacent card slots 41 in the same row of card slot groups is equal, the stroke of each movement of the piston rod 3 is fixed, thus effectively ensuring the accuracy of single-dose administration. In addition, when the pawl 42 exits the current card slot and enters the adjacent card slot 41, a "click" sound will be generated to remind the operator that the current administration has ended or is about to end, avoiding the operator from injecting too much or too little and affecting the accuracy of the administered dose.

[0030] In addition, a dose scale indication line is marked on the outer wall of the piston rod 3 to help the operator determine the current cumulative administered dose and the remaining drug amount.

[0031] It can be understood that one row of card slot groups or multiple rows of card slot groups are provided on the outer wall of the piston rod 3; there is no limitation in this regard. In this embodiment, it is preferably to provide multiple rows of card slot groups on the outer wall of the piston rod 3, and it is required that the card slots 41 in different rows of card slot groups have different sizes in the axial direction of the piston rod, or the card slots 41 in different rows of card slot groups have different arrangement spacings, and the sizes of the card slots 41 in different rows of card slot groups are the same. Thus, by simply rotating the piston rod 3 to switch different rows of card slot groups to the angular position corresponding to the pawl 42, the single-dose supply dose of the metered dose dispenser can be changed, effectively expanding the applicable range of the metered dose dispenser.

[0032] Specifically, as Figure 2As shown in the figure, the inner side of the card slot 41 away from the piston 2 is defined as the first inner side; the first inner side is an inclined surface that slopes from the outside to the inside towards the piston 2. When the piston rod 3 moves towards the drug delivery direction under a large external force, it will push the claw 42 to rotate away from the piston rod 3 through the first inner side, causing the claw 42 to withdraw from the current card slot and enter the adjacent next card slot 41; when the piston rod 3 continues to move under a small external force and the claw 42 contacts the first inner side of the adjacent card slot, the claw 42 will limit the continued movement of the piston rod 3. At this time, the piston rod 3 can only enter the next card slot under a large external force. Thus, every time drug is administered, the operator can determine whether the current drug administration is completed by perceiving the ease or difficulty of pushing the piston rod 3, reducing the requirements for the operator and having the advantages of convenient use and simple operation.

[0033] In this application, for the convenience of description, the height direction when the drug delivery cylinder 1 in the metered drug dispenser is in a horizontal state is defined as the up-down direction, the axial direction when the drug delivery cylinder 1 is in a horizontal state is defined as the front-back direction, and the direction perpendicular to both the up-down direction and the front-back direction is defined as the left-right direction. Based on this, in Figure 2 the lower side and the upper side of the paper surface are the front direction and the back direction respectively, the left side and the right side of the paper surface are the up direction and the down direction respectively, and the outer side and the inner side of the paper surface are the left direction and the right direction respectively.

[0034] See Figures 1 to 5 , a plate-shaped outer flange 11 is formed at the open end of the drug delivery cylinder 1, and a gripping member 5 is detachably arranged on the outer flange 11; wherein, the gripping member 5 is provided with a through hole for the piston rod 3 to move; the claw 42 is arranged on the gripping member 5 and is integrally formed therewith; the integrally formed member composed of the claw 42 and the gripping member 5 can be made of materials such as plastic or metal with elastic resilience, and no limitation is made thereto. Considering the cost, in this embodiment, the integrally formed member composed of the claw 42 and the gripping member 5 is preferably integrally injection molded with plastic.

[0035] In a preferred embodiment, as Figures 1 to 5 shown, the gripping member 5 includes a main body portion 51, and a flange slot 51a for plugging and mating with the outer flange 11 is provided on the side wall of the main body portion 51; a first through hole 51b for the axial movement of the piston rod 3 is provided on the main body portion 51, and the first through hole 51b communicates with the side wall of the main body portion provided with the flange slot 51a to form a first opening structure; thus, when the flange slot 51a is inserted on the outer flange 11 of the drug delivery cylinder 1, the piston rod 3 can pass through the first opening structure and enter the first through hole 51b to complete the detachable connection of the gripping member 5 and the drug delivery component (i.e., the assembled component of the drug delivery cylinder 1, the piston 2, and the piston rod 3).

[0036] In a preferred embodiment, the shape of the first through hole 51b can be determined according to the cross-sectional shape of the piston rod 3, as long as it is ensured that the piston rod 3 can only axially slide in the first through hole 51b and cannot rotate freely. In this way, during the drug administration process, the piston rod 3 will not accidentally rotate, causing the current card slot group to be misaligned with the claw 42 and affecting the dosing accuracy. To prevent the piston rod 3 from accidentally sliding out of the first opening structure, as Figure 4 and Figure 6 shown, a stop portion 54 can be formed on the main body portion 51, and the stop portion 54 is used to limit the piston rod 3 in the first through hole 51b to prevent the piston rod 3 from accidentally sliding out of the first through hole 51b. In addition, to reduce the difficulty of the piston rod 3 entering the first through hole 51b, the stop portion 54 includes a first guiding surface 541, and the first guiding surface 541 is an inclined surface; when the piston rod 3 is moved into the first through hole 51b, it will squeeze the first guiding surface 541 of the stop portion 54, so that the stop portion 54 rotates in the direction close to the first through hole 51b to ensure that the piston rod 3 smoothly enters the first through hole 51b; in this embodiment, there are two stop portions 54, and the two stop portions 54 are oppositely arranged on two opposite side walls of the first opening structure.

[0037] In a preferred embodiment, as Figures 1 to 7 shown, the grasping member 5 includes a guiding portion 53, and the guiding portion 53 is formed at one end of the main body portion 51 away from the piston 2; a second through hole 53a for the piston rod 3 to axially move only and not circumferentially rotate is provided on the guiding portion 53, and the rotation of the piston rod 3 is restricted through the second through hole 53a to prevent the piston rod 3 from accidentally rotating during the drug administration process and affecting the dosing accuracy; the second through hole 53a needs to communicate with the outer wall of the guiding portion 53 to form a second opening structure, and the opening direction of the second opening structure is the same as the insertion direction of the flange slot 51a. In this way, when the flange slot 51a is inserted into the outer flange 11, the piston rod 3 can enter the second through hole 53a through the second opening structure.

[0038] To prevent the piston rod 3 from accidentally sliding out of the second through hole 53a, as Figure 4 and Figure 6 shown, a stop portion 54 can be formed on the main body portion 51, and the stop portion 54 is used to limit the piston rod 3 in the second through hole 53a to prevent the piston rod 3 from accidentally sliding out of the second through hole 53a. In addition, to reduce the difficulty of the piston rod 3 entering the second through hole 53a, the stop portion 54 includes a first guiding surface 541, and the first guiding surface 541 is an inclined surface; when the piston rod 3 is moved into the second through hole 53a, it will squeeze the first guiding surface 541 of the stop portion 54, so that the stop portion 54 rotates in the direction close to the second through hole 53a to ensure that the piston rod 3 smoothly enters the second through hole 53a; in this embodiment, there are two stop portions 54, and the two stop portions 54 are oppositely arranged on two opposite side walls of the second opening structure.

[0039] Specifically, the preferred structure of the guiding portion 53 is as follows Figure 3 and Figure 5 shown. The guiding portion 53 includes two axially supporting members 531 arranged at intervals and an intermediate connecting member 532 for connecting the two axially supporting members 531; wherein, the extending direction of the axially supporting member 531 is parallel to the axial direction of the piston rod 3, and the intermediate connecting member 532 is perpendicularly arranged with respect to the axially supporting member 531; the distance between the two axially supporting members 531 is greater than the outer diameter of the piston rod 3 to allow the piston rod 3 to smoothly move into or out of the space between the two axially supporting members 531; the third through hole 53a is arranged on the intermediate connecting member 532 and communicates with the outer wall of the intermediate connecting member 532 to form a second opening structure to ensure the smooth entry or exit of the piston rod 3 into or out of the third through hole 53a; two stop portions 54 are oppositely arranged on the two axially supporting members 531. Since the guiding portion 53 is composed of the sheet-shaped axially supporting member 531 and the intermediate connecting member 532, it has the advantages of low cost and light weight.

[0040] In a more specific embodiment, as shown in Figures 1 to 5 shown, the grasping member 5 includes a clamping portion 52, and the clamping portion 52 is formed at one end of the main body portion 51 close to the piston 2; the clamping portion 52 is used for clamping the drug delivery cylinder 1, and the clamping portion 52 has a bayonet for the entry and exit of the drug delivery cylinder 1; by clamping the drug delivery cylinder 1 with the clamping portion 52, the installation stability of the grasping member 5 can be further improved. In addition, in order to prevent the drug delivery cylinder 1 from accidentally detaching from the clamping portion 52, limit blocks 521 can be arranged on the two side walls opposite to the bayonet to limit the drug delivery cylinder 1 in the clamping portion 52 from sliding out of the bayonet under a small external force, ensuring the installation stability of the grasping member 5.

[0041] As shown in Figure 2 , Figure 3 and Figure 5 shown, the claw 42 includes a cantilever member 421 and a hook 422, the hook 422 is arranged at one end of the cantilever member 421, and the cantilever member 421 is arranged at one end of the main body portion 51 far from the piston 2 or on the intermediate connecting member 532; in this embodiment, the middle portion or the end of the cantilever member 421 far from the hook 422 is connected to the intermediate connecting member 532.

[0042] It can be understood that when multiple rows of card slot groups are arranged on the outer wall of the piston rod 3, the cross-section of the piston rod 3 is preferably an equilateral triangle (as shown in Figure 6 shown), a square, a regular pentagon and other regular polygons (a circle can be regarded as a regular polygon with a large number of sides), and each row of card slot groups is arranged at the edges of the regular polygon to facilitate the switching of the angular positions of each row of card slot groups; when a row of card slot groups is arranged on the outer wall of the piston rod, the cross-section of the piston rod 3 can be a circle, a semi-circle (as shown in Figure 7 shown), a triangle or any other shape, and there is no limitation on this.

[0043] For the convenience of the operator, as shown inFigure 1 and Figure 2 As shown in Figure 2 , a pressing head 31 is formed at one end of the piston rod 3 away from the piston 2. The cross-sectional area of the pressing head 31 is larger than that of the piston rod 2 to improve the pressing comfort.

[0044] When the operator needs to administer a fixed-dose drug multiple times, it is necessary to first prepare a pre-filled drug syringe assembly (i.e., an assembly of the syringe 1, the piston 2, and the piston rod 3); determine the angular position of the claw 42 when the gripping member 5 is installed on the syringe 1, and then rotate the corresponding card slot group to the angular position of the claw 42 according to the drug dosage requirements for each time; insert the flange slot 51a of the gripping member 5 into the outer flange 11 of the syringe 1, so as to install the integral molding formed by the gripping member 5 and the claw 42 on the syringe 1; the index finger and middle finger of the operator support on the gripping member 5, and press the pressing head 31 of the piston rod 3 with the thumb to make the claw 42 contact the first inner side surface of a card slot 41, completing the preparation work before drug administration; the operator uses a relatively large external force to install the piston rod 3 to make the claw 42 withdraw from the current card slot and enter the adjacent next card slot until the claw 42 contacts the first inner side surface of the adjacent next card slot; determine whether the drug administration is completed this time by using the "click" sound of the claw 42 entering the card slot 41 and the ease of pressing the piston rod 3, which has the advantages of simple operation and high drug administration accuracy.

[0045] In summary, the utility model effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0046] The above embodiments are only illustrative of the principles and effects of the utility model, and are not used to limit the utility model. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the utility model. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the utility model should still be covered by the claims of the utility model.

Claims

1. A quantitative dosing device, comprising a dosing barrel (1), a piston (2) and a piston rod (3); the piston (2) is sealed and slidable in the dosing barrel (1), and one end of the piston rod (3) extends into the dosing barrel (1) and is fixedly connected to the piston (2); characterized in that: At least one row of slot groups is provided on the outer wall of the piston rod (3), and each row of slot groups includes a plurality of slots (41) evenly arranged along the axial direction of the piston rod (3); a claw (42) cooperating with the slot (41) is provided on the drug delivery barrel (1); when the piston rod (3) moves in a drug delivery direction relative to the drug delivery barrel (1), the claw (42) enters into different slots (41) in the same row of slot groups under the push of the piston rod (3).

2. A quantitative dosing device according to claim 1, characterized in that: The outer wall of the piston rod (3) is provided with a plurality of rows of slot groups; the slots (41) in different rows of slot groups have different sizes in the axial direction of the piston rod, or the slots (41) in different rows of slot groups have different arrangement spacings.

3. A quantitative dosing device according to claim 1 or 2, characterized in that: An outer flange (11) is formed at the open end of the drug delivery cartridge (1); a gripping piece (5) is detachably provided on the outer flange (11), and a through hole is provided on the gripping piece (5) for movement of the piston rod (3); the clamping claw (42) is provided on the gripping piece (5), and the clamping claw (42) and the gripping piece (5) are integrally formed.

4. A quantitative dosing device according to claim 3, characterized in that: The gripping member (5) comprises a main body (51), the side wall of which is provided with a flange slot (51a) which is plugged into and matched with the outer flange (11); the main body (51) is provided with a first through hole (51b) for axial movement of the piston rod (3), and the first through hole (51b) is connected to the side wall of the main body where the flange slot (51a) is provided to form a first opening structure.

5. A quantitative dosing device according to claim 4, characterized in that: A clamp portion (52) is formed on the main body portion (51), and the clamp portion (52) is used to clamp the drug cartridge (1).

6. A quantitative dosing device according to claim 5, characterized in that: The claw (42) is located at one end of the main body (51) away from the clamping hoop (52).

7. A quantitative dosing device according to claim 5, characterized in that: A guide portion (53) is formed at one end of the main body (51) away from the clamp portion (52); a second through hole (53a) for axial movement of the piston rod (3) is provided on the guide portion (53); the second through hole (53a) is connected to the outer wall of the guide portion (53) to form a second opening structure; the opening direction of the second opening structure is consistent with the insertion direction of the flange slot (51a).

8. A quantitative dosing device according to claim 7, characterized in that: A stopper (54) is formed on the guide portion (53); the stopper (54) is arranged at the second opening structure.

9. A quantitative dosing device according to claim 8, characterized in that: The stopper (54) comprises a first guide surface (541); when the piston rod (3) moves into the second through hole (53a), the first guide surface (541) of the stopper (54) is pressed to make the stopper (54) rotate in a direction close to the second through hole (53a).

10. A quantitative dosing device according to claim 9, characterized in that: The integrally formed part formed by the claw (42) and the gripping member (5) is made of plastic or metal having resilience.

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