A margin monitoring structure and a fluid administration device

Abstract

The present application belongs to the technical field of fluid administration device, and particularly relates to a residual amount monitoring structure and a fluid administration device. The residual amount monitoring structure comprises a shell, a dose setting ring and a residual amount monitoring ring. The residual amount monitoring ring is arranged between the shell and the dose setting ring. One end of the residual amount monitoring ring is provided with a starting surface. The shell is provided with a starting position limiting rib. Before dose setting, the starting surface is limited. During dose setting, the residual amount monitoring ring moves along the axial direction of the shell. The other end of the residual amount monitoring ring is provided with a terminal surface. The upper end of the shell is provided with a residual amount monitoring stopper. If the last predetermined set dose is greater than the residual dose of the liquid medicine, when the dose is set to the residual dose of the liquid medicine, the terminal surface can abut against the side surface of the residual amount monitoring stopper, thereby preventing the dose from being continuously set. The present application has the residual amount monitoring function and can display the last residual dose.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fluid administration device, and particularly relates to a residual amount monitoring structure and a fluid administration device. BACKGROUND

[0002] Fluid administration devices are used for injecting fluid medicine, such as injection pens commonly used in the prior art. Mechanical injection pens include single-throw mechanical injection pens and multi-throw mechanical injection pens. Single-throw mechanical injection pens are mainly used for single-dose (small-dose) injection of liquid medicine with a certain time interval (such as one week). Multi-throw mechanical injection pens are mainly used for multi-dose injection of liquid medicine with a high injection frequency (such as every day).

[0003] For multi-throw mechanical injection pens, there are multiple dose settings and multiple injections. After multiple injections, it is necessary to determine whether the residual amount of medicine can still meet the use of a single injection. If it cannot be determined whether the residual amount of medicine can still meet the use of a single injection, the effect of the last injection cannot be guaranteed. In addition, the locking function after injection cannot be achieved. SUMMARY

[0004] In order to solve at least one of the above technical problems in the prior art, the present application provides a residual amount monitoring structure and a fluid administration device. The residual amount monitoring structure and the fluid administration device can realize the function of locking after all the medicine is injected, and can realize the function of monitoring the residual amount of the last medicine. The patient can clearly observe the residual amount of the last medicine through a dose observation window in real time, and the residual un-injected dose can be scientifically controlled when the residual amount of the last medicine is less than a single injection dose.

[0005] To achieve the above object, the technical scheme of the present application is as follows:

[0006] In a first aspect, the present application provides a residual amount monitoring structure, comprising:

[0007] a housing, the housing being internally configured to accommodate a self-driven injection assembly for pushing an inner piston of a medicine bottle;

[0008] a dose setting ring, the dose setting ring being rotationally connected to the housing, and the dose setting ring being configured to set a dose by rotating the dose setting ring relative to the housing;

[0009] a residual amount monitoring ring, the residual amount monitoring ring being arranged between the housing and the dose setting ring;

[0010] One end of the residual amount monitoring ring has a starting surface, and the housing has a starting position positioning rib. Before dose setting, the starting surface abuts against the side surface of the starting position positioning rib. During dose setting, the residual amount monitoring ring moves along the axial direction of the housing.

[0011] The other end of the residual amount monitoring ring has a terminal surface, and the housing has a residual amount monitoring stopper, the terminal surface being capable of abutting against a side surface of the residual amount monitoring stopper when the last predetermined set dose is greater than the residual dose of the liquid medicine, thereby preventing the dose from being continuously set.

[0012] Further, the housing outer wall is provided with external threads, and the residual amount monitoring ring inner wall is provided with engaging threads which engage with the external threads.

[0013] The residual amount monitoring ring inner wall is provided with residual amount monitoring ring actuating ribs in the axial direction, and the residual amount monitoring ring outer wall is provided with driven rib grooves in which the residual amount monitoring ring actuating ribs are embedded.

[0014] Further, the residual amount monitoring ring actuating ribs are three in number, and the three residual amount monitoring ring actuating ribs are arranged in a circumferential array along the dose setting ring; the number of the driven rib grooves corresponds to the number of the residual amount monitoring ring actuating ribs.

[0015] Further, the housing outer wall is provided with a limiting surface, and the lower surface of the residual amount monitoring ring is in contact with the limiting surface; the limiting surface is provided with the start position positioning rib.

[0016] Further, the housing interior is provided with a fixing ring which is clamped with the housing, and the fixing ring outer wall is provided with the residual amount monitoring stopper; the housing is provided with a stop installation groove, and the residual amount monitoring stopper extends out of the housing through the stop installation groove.

[0017] Further, the self-driven injection assembly comprises a drive rod, and a scale is arranged between the housing and the drive rod, the scale outer wall is provided with a dose scale, and the housing is provided with an observation window.

[0018] The housing inner wall is provided with scale engaging threads, and the scale outer wall is provided with housing engaging thread grooves; the scale engaging threads are embedded in the housing engaging thread grooves.

[0019] The scale inner wall is provided with drive rod engaging ribs, and the drive rod outer wall is provided with scale engaging rib grooves in which the drive rod engaging ribs are embedded.

[0020] In a second aspect, the present application provides a fluid administration device, comprising:

[0021] A medicine bottle support which accommodates a medicine bottle;

[0022] A housing which is connected with the medicine bottle support;

[0023] The excess amount monitoring structure is arranged at the upper end of the shell.

[0024] Further, the fluid administration device further comprises:

[0025] A trigger mechanism is arranged at one end of the shell.

[0026] An autonomous driving injection assembly comprises a driving assembly and an injection assembly, and the driving assembly stores driving force during dose setting.

[0027] When the trigger mechanism is triggered, the driving assembly can drive the injection assembly to move towards the medicine bottle to achieve injection.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The excess amount monitoring structure provided by the present application can block the dose setting ring from continuing to set the dose if the set dose is greater than the remaining dose in the medicine bottle, thereby achieving the excess amount monitoring function. In addition, through the arrangement of the scale, the display of the last remaining dose can also be achieved, and the last remaining drug dose can be intuitively understood.

[0030] After the injection of the liquid medicine is completed, the scale is limited to the zero position, and the excess amount monitoring ring is limited to the termination surface, and the dose setting ring is limited in both positive and negative directions and is locked and cannot work, so that the entire administration device is locked and cannot be used, and the device is more reliable and intelligent. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a perspective view of the excess amount monitoring structure of the present application (for the convenience of understanding the structure, the shell part of the dose setting ring is removed, and the excess amount monitoring ring of the dose setting ring is retained) ;

[0032] Figure 2 It is a front view of the dose setting ring;

[0033] Figure 3 It is a bottom view of the dose setting ring;

[0034] Figure 4 It is a top view of the dose setting ring;

[0035] Figure 5 It is a schematic view of the internal structure of the dose setting ring;

[0036] Figure 6 It is a schematic view of the structure of the excess amount monitoring ring;

[0037] Figure 7 It is a schematic view of the structure of the dose setting ratchet;

[0038] Figure 8 isometric view of the fixed ring;

[0039] Figure 9 isometric view of the drive rod;

[0040] Figure 10 isometric view of the scale;

[0041] Figure 11 isometric view of the housing;

[0042] Figure 12 schematic view of the structure after dose setting of the present application;

[0043] Figure 13 schematic view of the structure of the fluid administration device provided by the present application.

[0044] Reference signs:

[0045] 1. Dose setting ring, 101, housing limiting slot, 102, drive arm, 103, residual amount monitoring ring prong;

[0046] 2. Fixed ring, 201, housing limiting rib, 202, residual amount monitoring stopper;

[0047] 3. Drive rod, 301, dose setting ring engagement tooth, 302, scale engagement rib slot;

[0048] 4. Scale, 401, housing engagement thread slot, 402, drive rod engagement rib, 403, scale end surface, 404, scale zero position limiting surface;

[0049] 5. Housing, 501, bidirectional ratchet engagement tooth slot, 502, observation window, 503, annular protruding rib, 504, external thread, 505, start position positioning rib, 506, stop position mounting slot;

[0050] 6. Residual amount monitoring ring, 601, start surface, 602, end surface, 603, engagement thread, 604, driven rib slot;

[0051] 7. Dose setting ratchet, 701, drive protrusion, 702, bidirectional ratchet tooth, 703, curved arm, 704, drive rod engagement tooth. DETAILED DESCRIPTION

[0052] The technical solutions of the present application will be described clearly below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all the embodiments of the present application, and all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present application.

[0053] It is to be understood that the embodiments presented herein are by way of illustration only and should not be construed in any way to limit the scope of the application. Unless otherwise specifically noted, the relative arrangement of components and the numerical expressions expressed in these embodiments should not be construed as limiting the scope of the application.

[0054] The following description of the exemplary embodiments is merely exemplary in nature and is in no way intended to limit the scope of the application, its application, or uses. Techniques, methods, and apparatus known to those of ordinary skill in the art can not be discussed in detail herein. However, where appropriate, such techniques, methods, and apparatus should be considered as part of this description.

[0055] Embodiment One

[0056] The present embodiment provides a residual amount monitoring structure, as shown in the figure, comprising a housing 5, a dose setting ring 1 and a residual amount monitoring ring 6, the housing 5 is internally provided with an autonomous drive injection assembly for setting a piston in a medicine bottle; the dose setting ring 1 is arranged outside one end of the housing 5, as shown in the figure, the dose setting ring 1 is sleeved outside the upper end of the housing 5. The dose setting ring 1 is rotationally connected with the housing 5; the dose setting ring 1 is configured to set the dose by rotating the dose setting ring 1 relative to the housing 5; the residual amount monitoring ring 6 is arranged between the housing 5 and the dose setting ring 1. Figure 1 Figure 1 The dose setting ring 1 is rotationally connected with the housing 5; the dose setting ring 1 is configured to set the dose by rotating the dose setting ring 1 relative to the housing 5; the residual amount monitoring ring 6 is arranged between the housing 5 and the dose setting ring 1.

[0057] One end of the residual amount monitoring ring 6 has a starting face 601, the housing 5 has a starting position positioning rib 505 on the upper end, before dose setting, the starting face 601 abuts against the side face of the starting position positioning rib 505; during dose setting, the residual amount monitoring ring 6 moves along the axial direction of the housing 5.

[0058] The other end of the residual amount monitoring ring 6 has a terminal face 602, the upper end of the housing 5 has a residual amount monitoring stopper 202, if the last predetermined set dose is greater than the residual dose of the medicine liquid, the terminal face 602 can abut against the side face of the residual amount monitoring stopper 202 when the dose is set to the residual dose of the medicine liquid, thereby preventing the dose from being continuously set.

[0059] As shown in the figure, the dose setting ring 1 has a toothed surface on the outer surface, which is beneficial for manually rotating the dose setting ring 1 to set the dose. The dose setting ring 1 comprises two layers of structure, specifically, an inner cylinder and an outer cylinder, the outer cylinder is sleeved outside the inner cylinder, and the two are connected through an intermediate connecting plate; the outer cylinder is connected with the housing 5, specifically, a housing limiting groove 101 is arranged on the lower inner wall of the outer cylinder, a corresponding annular convex rib 503 is arranged outside the housing 5, the annular convex rib 503 is embedded into the housing limiting groove 101, thereby realizing the connection between the housing 5 and the dose setting ring 1. Figures 2-5 The dose setting ring 1 is rotationally connected with the housing 5; the dose setting ring 1 is configured to set the dose by rotating the dose setting ring 1 relative to the housing 5; the residual amount monitoring ring 6 is arranged between the housing 5 and the dose setting ring 1.​

[0060] A driving arm 102 is arranged below the connecting plate in the space between the outer cylinder and the inner cylinder, and the front end of the driving arm 102 abuts against the driving protrusion 701 of the dose setting ratchet 7 in the clockwise direction as the advancing direction of dose setting.

[0061] When the housing 5 is connected with the dose setting ring 1, the upper end of the housing 5 is inserted into the space between the outer cylinder and the inner cylinder of the dose setting ring 1.

[0062] In addition, the inner wall of the outer cylinder of the dose setting ring 1 is provided with a residual amount monitoring ring actuating rib 103 which cooperates with the driven rib groove 604 on the residual amount monitoring ring 6, and when setting the dose, the dose setting ring 1 drives the residual amount monitoring ring 6 to rotate.

[0063] Figure 6 The residual amount monitoring ring 6 is a whole circular ring structure, and the lower surface thereof has a starting surface 601 which is limited by the starting position limiting rib 505 on the housing 5 in the initial state; the upper surface of the residual amount monitoring ring 6 has a terminal surface 602, and if the last predetermined set dose is greater than the residual dose of the liquid medicine, the terminal surface 602 is limited by the residual amount monitoring block 202 when the dose is set to the residual dose of the liquid medicine, thereby preventing the dose from being continuously set.

[0064] The outer surface of the residual amount monitoring ring 6 is further provided with a plurality of driven rib grooves 604 in which the residual amount monitoring ring actuating rib 103 is embedded. The inner wall of the residual amount monitoring ring 6 is further provided with a meshing thread 603 which cooperates with the external thread 504 on the housing 5.

[0065] Figure 11 The upper end outer wall of the housing 5 is provided with the external thread 504, and the meshing thread 603 of the inner wall of the residual amount monitoring ring 6 cooperates with the external thread 504 of the housing 5, thereby moving the residual amount monitoring ring 6 in the axial direction when the residual amount monitoring ring 6 is driven to rotate by the dose setting ring 1.

[0066] The inner wall of the upper end of the housing 5 is provided with a bidirectional ratchet meshing tooth groove 501, in addition, a plurality of stop installation grooves 506 are arranged on the upper end side wall of the housing 5 below the external thread 504, the outer wall of the housing 5 is provided with an annular protruding rib 503 which is used for connecting with the dose setting ring 1 and does not limit the rotation freedom degree of the dose setting ring 1.

[0067] The upper surface of the annular protruding rib 503 is a limiting surface of the residual amount monitoring ring 6, and a plurality of starting position limiting ribs 505 are arranged above the limiting surface, and the starting surface 601 of the residual amount monitoring ring 6 contacts the side surface of the starting position limiting rib 505 in the initial state.

[0068] The side wall of the shell 5 is also provided with an observation window 502, through which the scale of the scale 4 can be observed to visually observe the set dose.

[0069] As Figure 8 The outer surface of the fixed ring 2 is provided with a shell limiting rib 201, which is a tooth-shaped structure engaged with the bidirectional ratchet engaging tooth groove 501. By embedding the shell limiting rib 201 into the bidirectional ratchet engaging tooth groove 501, the fixed ring 2 is limited in the shell 5. In addition, the outer wall of the fixed ring 2 is also provided with a buckle, which is buckled into the buckle hole in the inner wall of the shell 5 to fixedly connect the fixed ring 2 with the shell 5.

[0070] The outer wall of the fixed ring 2 is also provided with a residual amount monitoring stop block 202, which is extended outside the shell 5 through the stop installation groove 506 on the shell 5, thereby forming a blocking structure to block the upward movement of the rotation axis of the residual amount monitoring ring 6.

[0071] Figure 7 The structure of the dose setting ratchet 7 is shown in the figure. The inner wall of the dose setting ratchet 7 is provided with a driving rod engaging tooth 704 for driving the rotation of the driving rod 3. The outer wall of the dose setting ratchet 7 is provided with a curved arm 703, which is a structure with one end fixed and the other end free, so it is deformable, and the curved arm 703 extends in the opposite direction of the dose setting rotation direction.

[0072] The outer part of the curved arm 703 is provided with a bidirectional ratchet tooth 702. In this embodiment, two curved arms 703 are provided, and one bidirectional ratchet tooth 702 is provided on each curved arm 703. The inner wall of one end of the shell 5 is provided with a bidirectional ratchet engaging tooth groove 501, and the bidirectional ratchet engaging tooth groove 501 and the bidirectional ratchet tooth 702 are engaged.

[0073] The outer wall of the dose setting ratchet 7 is also provided with a driving protrusion 701, and two driving protrusions 701 and two curved arms 703 are staggered. In addition, during dose setting, the front end of the driving arm 102 drives the driving protrusion 701 to rotate, thereby driving the rotation of the dose setting ratchet 7. The curved arm 703 of the dose setting ratchet 7 is blocked by the bidirectional ratchet engaging tooth groove 501, and the curved arm 703 is deformed to make the bidirectional ratchet tooth 702 engage with the next bidirectional ratchet engaging tooth groove 501. In the process of deformation and engagement, a "click" sound is produced, which increases the friendly user experience.

[0074] Figure 9As a structural schematic diagram of the driving rod 3, the driving rod 3 comprises a driving rod sleeve and a driving rod cylinder, the driving rod sleeve is sleeved outside the driving rod cylinder, and the lower end of the driving rod sleeve and the driving rod cylinder are fixedly connected; in the embodiment, the driving rod sleeve and the driving rod cylinder are detachably connected, specifically, the lower end of the driving rod sleeve is provided with a buckle, the outer wall of the driving rod cylinder is provided with a clamping strip, and the buckle and the clamping strip are clamped to realize the connection of the driving rod sleeve and the driving rod cylinder.

[0075] A dose setting ring engagement tooth 301 is arranged on the top outer wall of the driving rod 3, and the dose setting ring engagement tooth 301 is engaged with the driving rod engagement tooth 704.

[0076] A plurality of scale engagement ribs 302 extending in the axial direction are arranged on the outer wall of the driving rod 3, the inner wall of the scale 4 is provided with a driving rod engagement rib 402, the driving rod engagement rib 402 is embedded in the scale engagement rib groove 302, and in turn, when the driving rod 3 rotates, the scale 4 can rotate synchronously with the driving rod 3.

[0077] Figure 10 As a structural schematic diagram of the scale 4, the outer wall of the scale 4 is provided with a shell engagement thread groove 401, and the inner wall of the shell 5 is provided with a scale engagement thread, the scale engagement thread is embedded in the shell engagement thread groove 401; in turn, the radial rotation movement of the scale 4 can be converted into a combination of axial movement and radial rotation.

[0078] The outer wall of the scale 4 can be provided with a scale, and the scale 4 can display the set dose during dose setting. The upper end of the scale 4 is provided with a scale termination surface 403, and the scale termination surface 403 contacts with the scale termination limiting surface of the fixed ring 2 to limit the upper end of the scale 4. The lower end of the scale 4 is provided with a scale zero position limiting surface 404 for limiting the lower end of the scale 4.

[0079] The inner wall of the scale 4 is provided with a driving rod engagement rib 402 extending in the axial direction, which matches the scale engagement rib groove 302 on the outer wall of the driving rod 3.

[0080] As shown in Figure 13 the initial state, the scale zero position limiting surface 404 of the scale 4 is limited. During dose setting, the dose is set by rotating the dose setting ring 1 clockwise, after rotating the dose setting ring 1, the dose setting ring 1 drives the driving rod 3 to rotate through the dose setting ratchet 7 by the engagement of the driving rod engagement tooth 704 and the dose setting ring engagement tooth 301, at the same time, the bidirectional ratchet tooth 702 and the bidirectional ratchet engagement tooth groove 501 are engaged, and the setting of the dose is realized through the deformation of the bending arm 703 and the circulation of the engagement.

[0081] At the same time, after rotating the dose setting ring 1, the drive rod 3 rotates, driving the scale 4 to rotate. Since the scale 4 is engaged with the scale thread of the outer shell 5, the scale 4 moves axially and rotates radially. After dose setting, the scale 4 moves a certain displacement towards the fixed ring 2. The scale on the scale 4 can be observed through the observation window 502, i.e. the dose setting amount.

[0082] As shown in Figure 1 The initial position and state of the remaining amount monitoring ring 6 are shown. The dose is set by rotating the dose setting ring 1. During dose setting, clockwise rotation of the dose setting ring 1 drives the remaining amount monitoring ring 6 to rotate. The remaining amount monitoring ring 6 is constrained by the outer thread 504 and moves axially from the lower part to the upper part.

[0083] During injection, the dose setting ring 1 does not rotate, so the remaining amount monitoring ring 6 stops at a certain position of the outer thread 504 and is stationary relative to the outer shell 5.

[0084] During the next dose setting, the remaining amount monitoring ring 6 continues to move axially towards the upper end of the outer shell 5 by a certain distance. Assuming that all the medicament in the medicine bottle is injected completely, the push rod inside the drive rod 3 needs to rotate by A degrees. The maximum injection dose of the push rod is B degrees per rotation. If the maximum dose is injected each time, the number of injections N is A / B.

[0085] The number of degrees by which the remaining amount monitoring ring 6 rotates from the starting surface 601 to the ending surface 602 is set to be consistent with the number of rotations of the push rod to inject all the medicament completely, which is also A. Assuming that after the previous injection action is completed, the remaining medicament is injected completely, the push rod needs to rotate by b degrees. At this time, if b>B, since the remaining amount monitoring remaining rotatable number of turns is also b, the dose setting can still complete single maximum dose setting and injection.

[0086] If b<B, the remaining amount monitoring rotatable number of turns b is less than the single maximum injection dose rotation number, so the dose setting ring 1 rotates to the position where the remaining amount monitoring ring 6 is blocked by the stop surface. After that, it cannot continue to rotate. At this time, the observation window 502 displays the same dose as the actual remaining dose in the medicine bottle, thereby achieving the remaining amount monitoring function.

[0087] When all the doses are injected completely, as shown in Figure 12 The ending surface 602 of the remaining amount monitoring ring 6 abuts against the remaining amount monitoring stop block 202 and cannot continue to rotate. Simultaneously, the dose setting knob cannot be rotated clockwise.

[0088] Simultaneously, the scale 4 is at zero position. Counterclockwise rotation of the scale 4 less than zero position is also limited. It can be understood that the dose setting ring 1 is limited in both forward and reverse directions and is locked and cannot work, thereby achieving the function that the device is locked and cannot be used after all the injections are completed.

[0089] Embodiment two

[0090] The embodiment provides a fluid administration device, comprising:

[0091] a medicine bottle support containing a medicine bottle;

[0092] a housing connected with the medicine bottle support;

[0093] the residual amount monitoring structure of embodiment one, the upper end of the housing is provided with the residual amount monitoring structure;

[0094] a trigger mechanism arranged at one end of the housing;

[0095] a self-driven injection assembly, the self-driven injection assembly comprises a driving assembly and an injection assembly, the driving assembly stores driving force when the dose is set;

[0096] when the trigger mechanism is triggered, the driving assembly can drive the injection assembly to move towards the medicine bottle, so as to realize injection.

[0097] The above detailed description is only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application has been described in detail with reference to the examples, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the scope of the technical solutions of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A residual amount monitoring structure, comprising: a housing, inside of which is arranged an autonomous drive injection assembly for pushing a piston in a medicine bottle; a dose setting ring, which is rotationally connected with the housing; the dose setting ring is configured to set a dose by rotation of the dose setting ring relative to the housing; characterized in that further comprising: a residual amount monitoring ring, which is arranged between the housing and the dose setting ring; one end of the residual amount monitoring ring has a starting face, and the housing has a starting position positioning rib, before dose setting, the starting face abuts against a side surface of the starting position positioning rib; during dose setting, the residual amount monitoring ring moves along an axial direction of the housing; the other end of the residual amount monitoring ring has a terminal face, and the housing has a residual amount monitoring stopper, if the last predetermined set dose is greater than the residual dose of the medicine liquid, when the dose is set to the residual dose of the medicine liquid, the terminal face can abut against a side surface of the residual amount monitoring stopper, thereby preventing the dose from being continuously set; an outer thread is arranged on an outer wall of the housing, and an engagement thread is arranged on an inner wall of the residual amount monitoring ring, the engagement thread engages with the outer thread; the outer wall of the housing has a limiting face, and a lower surface of the residual amount monitoring ring is in contact with the limiting face; the limiting face is provided with the starting position positioning rib; an axial residual amount monitoring ring poking rib is arranged on an inner wall of the dose setting ring, and a driven rib groove is arranged on an outer wall of the residual amount monitoring ring, the residual amount monitoring ring poking rib is embedded in the driven rib groove; the autonomous drive injection assembly comprises a drive rod, and a scale is arranged between the housing and the drive rod, an upper end of the scale is provided with a scale terminal face, and a lower end of the scale is provided with a scale zero position limiting face; a scale engagement thread is arranged on an inner wall of the scale, and a housing engagement thread groove is arranged on an outer wall of the scale; the scale engagement thread is embedded in the housing engagement thread groove; a drive rod engagement rib is arranged on an inner wall of the scale, and a scale engagement rib groove is arranged on an outer wall of the drive rod, the drive rod engagement rib is embedded in the scale engagement rib groove; the dose setting ring comprises an inner cylinder and an outer cylinder, a housing limiting groove is arranged on a lower inner wall of the outer cylinder, and a corresponding annular convex rib is arranged on an outer portion of the housing, the annular convex rib is embedded in the housing limiting groove, thereby connecting the housing and the dose setting ring, and not limiting the rotational freedom of the dose setting ring; when all doses are injected, the scale is at zero position, and the scale is limited to rotate counterclockwise less than the zero position, the dose setting ring is limited to rotate forward and reverse, and is locked and unable to work.

2. The structure for monitoring a residual amount according to claim 1, wherein a fixing ring is arranged inside the housing, an outer wall of the fixing ring is provided with the residual amount monitoring stopper; the housing is provided with a stop installation groove, and the residual amount monitoring stopper extends out of the housing through the stop installation groove.

3. The structure for monitoring a residual amount according to claim 2, wherein the fixing ring is clamped with the housing.

4. The structure for monitoring a residual amount according to claim 1, wherein a dose scale is arranged on an outer wall of the scale, and an observation window is arranged on the housing; rotation of the drive rod pushes the scale to rotate and move axially, thereby displaying the dose scale representing the set dose through the observation window.

5. A fluid administration set, comprising: comprising: a medicine bottle support, which accommodates a medicine bottle; a housing connected with the vial holder; The residual amount monitoring structure of any one of claims 1-4, wherein an upper end of the housing is provided with the residual amount monitoring structure.

6. The fluid administration set of claim 5, wherein, The fluid administration device further comprises: a trigger mechanism arranged at one end of the housing; a self-powered injection assembly, the self-powered injection assembly comprising a drive assembly and an injection assembly, the drive assembly storing a driving force during dose setting; when the trigger mechanism is triggered, the drive assembly is capable of driving the injection assembly to move towards the vial to achieve injection.

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