Fluid infusion mechanism

Abstract

The invention relates to the technical field of infusion pumps, in particular to a fluid infusion mechanism which comprises a guide screw, a driving wheel and a sleeve, guide threads are arranged on the periphery of the guide screw, a hole is formed in the center of the driving wheel, the driving wheel can rotate around the center of the hole, internal threads are arranged on the sleeve, and the sleeve is connected with the guide screw through matching of the internal threads and the guide threads. The sleeve penetrates through the hole part of the driving wheel, and the sleeve and the driving wheel are configured to be free of circumferential relative movement; an elastic structure is arranged on the driving wheel and has a tensioning state and a releasing state, and a triggering structure used for triggering the elastic structure to be switched between the tensioning state and the releasing state is arranged outside the elastic structure. According to the fluid infusion mechanism, the connecting structure of the sleeve and the driving wheel is optimized, the axial limiting assembly is additionally arranged, the axial displacement of the sleeve during rotation is effectively limited, it is ensured that rotation of the driving wheel can be stably converted into axial propelling motion of the screw, and therefore the reliability and stability of fluid infusion are improved.

Description

Technical Field

[0001] This invention relates to the field of infusion pump technology, and in particular to a fluid infusion mechanism. Background Technology

[0002] Insulin pumps are essential devices for the long-term treatment of diabetes patients, enabling complex insulin delivery modes, including variable basal infusion rates and booster doses. By precisely controlling the drug delivery process, they improve treatment efficacy and reduce drug harm to patients. Existing miniaturized wearable insulin pumps typically include components such as an insulin reservoir, a drive mechanism, and an infusion screw. The drive mechanism uses a drive wheel to move the infusion screw to achieve quantitative insulin infusion.

[0003] For example, the patent with publication number CN216536399U discloses a fluid delivery device, including a reservoir and a plunger driver assembly. The plunger driver assembly includes a sleeve and a screw, and the sleeve is driven by a drive wheel to rotate relative to the screw, causing the screw to move axially, and then pushing the plunger at the end of the screw to infuse the insulin in the reservoir into the patient's body.

[0004] However, the above structure has a key defect in actual infusion process: there is no effective axial limiting structure between the sleeve and the drive wheel. When the drive wheel drives the sleeve to rotate, the sleeve is prone to move backward along the screw axis under the axial reaction force generated by the threaded engagement with the screw. This causes the rotation of the drive wheel to be unable to be effectively converted into the axial movement of the infusion screw, resulting in the infusion screw being stationary and unable to push the plunger to infuse the drug, which seriously hinders normal infusion. Summary of the Invention

[0005] To address the technical problem of axial retraction of the sleeve leading to injection failure during the injection process in existing threaded sleeves and lead screws, this invention provides a fluid injection mechanism. By optimizing the connection structure between the sleeve and the drive wheel and adding an axial limiting component, the axial displacement of the sleeve during injection is effectively limited, ensuring that the rotation of the drive wheel can be stably converted into the axial propulsion motion of the lead screw, thereby improving the reliability and stability of fluid injection.

[0006] This invention provides a fluid delivery mechanism, comprising: The lead screw has a guide thread on its outer circumference. The drive wheel has a hole at its center and can rotate around the center of the hole. The sleeve has an internal thread and is connected to the lead screw through the engagement of the internal thread and the guide thread. The sleeve passes through the hole of the drive wheel, and the sleeve and the drive wheel are configured to have no circumferential relative motion. The drive wheel is provided with an elastic structure, which has a tensioned state and a released state. The outside of the elastic structure is provided with a triggering structure for triggering the switching between the tensioned state and the released state. In the initial state, the elastic structure is in contact with the trigger structure, and the elastic structure is in a tensioned state, allowing the lead screw to drive the sleeve to move axially within the drive wheel hole for fluid filling; when the elastic structure disengages from the trigger structure, the elastic structure switches from the tensioned state to the released state, restricting the axial movement of the sleeve, and allowing the lead screw to advance axially under the cooperation of the internal thread and the lead thread for fluid injection.

[0007] Through the cooperation of the elastic structure and the triggering structure, during the fluid filling stage, the elastic structure is in a tensioned state, and there is no axial limit between the sleeve and the drive wheel. The guide screw can drive the sleeve to easily retract along the hole of the drive wheel, ensuring a smooth filling process. During the infusion stage, the elastic structure releases after disengaging from the triggering structure and axially limits the sleeve, so that the rotation of the drive wheel can be stably transmitted to the guide screw, ensuring the accuracy and stability of the infusion dose.

[0008] Furthermore, an anti-rotation structure is provided between the bore of the drive wheel and the sleeve for circumferential positioning of the drive wheel and the sleeve. The anti-rotation structure includes mutually adaptable protrusions and recesses, one of which is located on the outer surface of the sleeve, and the other is located on the inner wall of the bore of the drive wheel. When the elastic structure axially limits the sleeve, the drive wheel can drive the sleeve to rotate synchronously through the cooperation of the protrusion and recess.

[0009] Furthermore, the protrusion is a strip-shaped ridge extending axially along the sleeve, and the recess is a strip-shaped groove extending axially along the drive wheel bore. The strip-shaped ridge and the strip-shaped groove are in clearance fit. The clearance fit allows the sleeve to slide axially within the drive wheel bore while restricting relative circumferential rotation.

[0010] Furthermore, the elastic structure includes at least two sets of elastic elements, which are evenly distributed along the circumference of the drive wheel. By evenly distributing the elastic elements along the circumference of the drive wheel, the axial positioning of the sleeve can be more stable, avoiding eccentricity of the sleeve due to excessive local force, ensuring the coaxiality between the sleeve and the drive wheel, and further guaranteeing the smoothness of power transmission.

[0011] Furthermore, a protrusion or recess is provided at one end of the sleeve, and locking portions that are adapted to the elastic element are evenly arranged along the axial direction on the outer surface of the other end of the sleeve. The locking portions provide a stable point of force application for the elastic element, further enhancing the stability of the elastic element in axially limiting the sleeve.

[0012] Furthermore, the elastic element is an arc-shaped spring sheet, which has a fixed end and a free end. The fixed end is fixedly connected to the drive wheel, and the free end extends toward the sleeve to form a locking part. The free end of the arc-shaped spring sheet is spread out in a direction away from the center of the drive wheel. After release, the locking part abuts against the locking part under the action of elasticity to limit the movement.

[0013] Furthermore, the elastic element includes a spring and a locking block. One end of the locking block is movably mounted on the drive wheel via the spring and can be radially displaced relative to the drive wheel bore. The other end of the locking block extends toward the sleeve and forms a second locking portion. When the locking block is opened away from the center of the drive wheel, the spring is in a tensioned state. After release, the second locking portion, under the elastic action of the spring, drives the locking block to abut against the locking portion for limiting.

[0014] Furthermore, multiple mounting blocks corresponding to the locking block are provided on the end face of the drive wheel. These mounting blocks are evenly distributed along the circumference of the drive wheel, and guide grooves are provided on the mounting blocks. The locking block is slidably disposed within the guide grooves. The guide grooves provide guidance for the radial displacement of the locking block, effectively preventing the locking block from shifting or jamming during movement, and ensuring that the locking block can stably engage with the locking part.

[0015] Furthermore, the curved spring or locking block is also provided with a spreading part. The triggering structure and the spreading part cooperate with each other. When the elastic structure is in a tensioned state, the spreading part abuts against the periphery of the triggering structure. The elastic element is expanded by the cooperation of the triggering structure and the spreading part. After the restriction of the spreading part is removed, the elastic element returns to its original state and limits the sleeve.

[0016] Furthermore, the locking part is an annular limiting groove provided on the outer surface of the sleeve. When the elastic structure is in the released state, either the first or second engaging part engages into the annular limiting groove. The annular limiting groove can be adapted to the engaging part, forming an axial constraint on the engaging part and preventing the sleeve from being displaced axially on the drive wheel.

[0017] Furthermore, the triggering structure is a triggering part installed on the housing or reservoir of the fluid delivery mechanism, and the triggering part is adapted to the supporting part. The triggering part can be configured as a boss, support plate, or other structural form, and its outer surface can be stably supported by the supporting part.

[0018] The beneficial effects of this invention are as follows: This invention provides a fluid delivery mechanism. By optimizing the connection structure between the sleeve and the drive wheel, and increasing the cooperation between the elastic structure and the triggering structure, axial limiting of the sleeve is achieved during fluid delivery. During the fluid filling stage, the elastic structure remains tensioned under the action of the triggering structure, and the guide screw can drive the sleeve to retract axially, ensuring smooth filling of the reservoir. During the delivery stage, the elastic structure releases after disengaging from the triggering structure and axially restricts the sleeve, so that the rotational torque of the drive wheel can be stably transmitted to the sleeve, thereby enabling the guide screw to advance axially stably, ensuring the accuracy and stability of the delivery. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort. Figure 1 This is an overall diagram of the fluid delivery mechanism with arc-shaped springs; Figure 2 yes Figure 1 Diagram of the infusion component structure; Figure 3 yes Figure 2 Disassembly diagram; Figure 4 yes Figure 3 A schematic diagram of the engagement between the drive wheel and the spring plate; Figure 5 This is an overall diagram of the fluid delivery mechanism with elastic locking blocks; Figure 6 yes Figure 5 Diagram of the infusion component structure; Figure 7 yes Figure 6 Disassembly diagram; Figure 8 yes Figure 7 A schematic diagram showing the interaction between the drive wheel and the elastic locking block; Figure 9 yes Figure 8 External schematic diagram of the mounting block; Figure 10 yes Figure 8 Internal diagram of the mounting block; Figure 11 This is a schematic diagram of the first angle at which the trigger part is set on the housing; Figure 12 This is a second-angle schematic diagram showing the trigger unit mounted on the housing; Figure 13 This is an overall diagram of the fluid delivery mechanism without the sleeve; Figure 14 yes Figure 13 A diagram illustrating the tension state; Figure 15 yes Figure 13 A schematic diagram of the release state; In the figure: 1. Lead screw, 11. Guide thread, 2. Drive wheel, 21. Hole, 22. Strip groove, 23. Mounting block, 24. Guide groove, 3. Sleeve, 31. Internal thread, 32. Strip ridge, 33. Annular limiting groove, 4. Arc-shaped spring, 41. Fixed end, 42. Free end, 43. Engaging part one, 5. Spring, 6. Locking block, 61. Engaging part two, 62. Spreading part, 7. Triggering part, 8. Fluid delivery mechanism, 81. Housing, 82. Liquid reservoir. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] To address the problem of traditional fluid delivery mechanisms lacking axial restraint on the sleeve 3, which easily leads to delivery failure, a new fluid delivery mechanism is designed, such as... Figure 1 As shown, the device includes a lead screw 1, a drive wheel 2, and a sleeve 3. The lead screw 1 has a guide thread 11 on its outer periphery. The drive wheel 2 has a hole 21 at its center and can rotate around the center of the hole 21. The sleeve 3 has an internal thread 31 and is connected to the lead screw 1 through the cooperation of the internal thread 31 and the guide thread 11. The sleeve 3 passes through the hole 21 of the drive wheel 2, and the sleeve 3 and the drive wheel 2 are configured to have no circumferential relative motion. An anti-rotation structure is provided between the hole 21 of the drive wheel 2 and the sleeve 3 to achieve circumferential positioning of the drive wheel 2 and the sleeve 3. The anti-rotation structure includes mutually adaptable protrusions and concave parts. One of the protrusions and concave parts is provided on the outer surface of the sleeve 3, and the other is provided in the hole 21 of the drive wheel 2, so that the drive wheel 2 can stably transmit rotational torque to the sleeve 3 through the cooperation of the protrusions and concave parts.

[0022] Preferably, the protrusion is a strip-shaped protrusion 32 extending axially along the sleeve 3, and the concave part is a strip-shaped groove 22 extending axially along the hole 21 of the drive wheel 2. The strip-shaped protrusion 32 and the strip-shaped groove 22 are in clearance fit. The strip-shaped protrusion 32 is embedded in the strip-shaped groove 22, thereby restricting the relative rotation between the sleeve 3 and the drive wheel 2, so that when the drive wheel 2 rotates, it can drive the sleeve 3 to rotate synchronously through the cooperation of the strip-shaped groove 22 and the strip-shaped protrusion 32.

[0023] The core of this technical solution lies in, for example Figure 2 and 6As shown, the drive wheel 2 is equipped with an elastic structure, which has a tensioned state and a released state. An external triggering structure is provided on the elastic structure to initiate the switching between the tensioned and released states. Before the fluid injection mechanism is assembled, the elastic structure is stretched open and placed against the periphery of the triggering structure. At this time, the elastic structure is stably in a tensioned state, facilitating subsequent fluid filling and injection.

[0024] The specific principle is as follows: In the initial state, the elastic structure is in contact with the trigger structure and the elastic structure is in a tensioned state, allowing the guide screw 1 to drive the sleeve 3 to axially retract within the hole 21 of the drive wheel 2 for fluid filling; when the elastic structure disengages from the trigger structure, the elastic structure switches from the tensioned state to the released state, the elastic structure engages with the sleeve 3 and axially limits the sleeve 3, and the drive wheel 2 drives the sleeve 3 to rotate synchronously, so that the guide screw 1 is axially advanced under the cooperation of the internal thread 31 and the guide thread 11 for fluid injection.

[0025] During the fluid filling stage, since the elastic structure is under tension and does not contact the sleeve 3, the guide screw 1 can drive the sleeve 3 to retract axially along the hole 21 of the drive wheel 2 under the pressure of fluid filling, thereby completing the suction and filling of fluid in the reservoir 82. When the fluid delivery stage begins, the drive wheel 2 rotates, causing the elastic structure to detach from the trigger structure. Losing the support of the trigger structure, the elastic structure switches to a released state under its own elastic force. After release, it makes tight contact with the outer surface of the sleeve 3, achieving axial restraint on the sleeve 3 and integrating the drive wheel 2 and the sleeve 3. At this point, the rotational torque of the drive wheel 2 is first transmitted to the sleeve 3 through the anti-rotation structure. Simultaneously, the released elastic structure further transmits the rotational force of the drive wheel 2 to the sleeve 3, ensuring that the sleeve 3 rotates synchronously and stably with the drive wheel 2, effectively preventing the sleeve 3 from retracting relative to the lead screw 1. The rotation of the sleeve 3 causes the internal thread 31 and the guide thread 11 to undergo relative helical motion. The lead screw 1 then advances axially under this reverse engagement, thereby pushing the fluid in the reservoir 82 and achieving precise fluid delivery. A plunger extending into the reservoir 82 is connected to the end of the lead screw 1. The rotation of the sleeve 3 is converted into axial movement of the lead screw 1, which in turn pushes the plunger axially, completing the fluid delivery.

[0026] To provide more stable axial restraint for the sleeve 3, the elastic structure includes at least two sets of elastic elements, which are evenly distributed along the circumference of the drive wheel 2. For example, Figure 4 As shown, two symmetrical arc-shaped spring pieces 4 can be set, and as shown in the figure... Figure 8 As shown, three sets of elastic elements can be set. The three sets of elastic elements are distributed at 120° with the central axis of the drive wheel 2 as the center. The circumferential distribution of multiple sets of elastic elements can make the pressure of the elastic elements on the outer surface of the sleeve 3 more evenly applied in all directions of the circumference, further enhancing the axial constraint effect on the sleeve 3.

[0027] like Figure 3 and 7 As shown, to further enhance the engagement reliability between the elastic element and the sleeve 3, a protrusion or recess is provided at one end of the sleeve 3, and locking portions that are compatible with the elastic element are evenly arranged along the axial direction on the outer surface of the other end of the sleeve 3. The protrusion or recess is provided at the end of the sleeve 3 away from the liquid reservoir 82, and the locking portions are provided on the part of the sleeve 3 close to the liquid reservoir 82.

[0028] Preferably, the locking part is an annular limiting groove 33 provided on the outer surface of the sleeve 3. When the elastic structure is in the released state, the engaging part 43 or the engaging part 61 engages into the annular limiting groove 33. Through the cooperation between the annular limiting groove and the engaging part of the elastic element, a stable axial positioning of the sleeve 3 is formed. The locking part can also be provided as a spiral structure, which can be stably abutted by the engaging part for axial limiting.

[0029] like Figures 1-4 As shown, the elastic element can adopt a spring sheet structure. The elastic element is an arc-shaped spring sheet 4. The arc-shaped spring sheet 4 has a fixed end 41 and a free end 42. The fixed end 41 is fixedly connected to the drive wheel 2, and the free end 42 extends toward the sleeve 3 and forms a locking part 43.

[0030] The fixed end 41 of the arc-shaped spring piece 4 is fastened to the end face of the drive wheel 2 by bolts or welding to ensure that the arc-shaped spring piece 4 will not loosen or fall off during the rotation of the drive wheel 2. The main body of the arc-shaped spring piece 4 is curved in an arc shape, and its curvature matches the curvature of the outer circumference of the sleeve 3, so that in its natural state, the arc-shaped spring piece 4 can engage with the annular limiting groove 33 on the outer surface of the sleeve 3. The spreading part 62 abuts against the periphery of the trigger part 7, so that the free end 42 tends to move towards the central axis of the sleeve 3 under the elastic action of the arc-shaped spring piece 4. Once the drive wheel 2 rotates and causes the spreading part 62 to disengage from the trigger part 7, the free end 42 will drive the engaging part 43 to abut against the annular limiting groove 33 on the outer surface of the sleeve 3 under the rebound action of the spring piece, so as to complete the axial limiting of the sleeve 3.

[0031] like Figures 5-10As shown, the elastic element can also be an elastic locking block structure. The elastic element includes a spring 5 and a locking block 6. One end of the locking block 6 is movably mounted on the drive wheel 2 via the spring 5 and can be radially displaced relative to the hole 21 of the drive wheel 2. The other end of the locking block 6 extends toward the sleeve 3 and forms a second locking part 61. Multiple mounting blocks 23 corresponding to the locking block 6 are provided on the end face of the drive wheel 2. The multiple mounting blocks 23 are evenly distributed along the circumference of the drive wheel 2. Guide grooves 24 are provided on the mounting blocks 23, and the locking block 6 is slidably mounted within the guide grooves 24. The mounting blocks 23 have slots communicating with the hole 21, allowing the second locking part 61 to extend and retract. The locking block 6 is slidably mounted within the guide grooves 24 via the spring. During assembly, the expansion part 62 on the locking block 6 abuts against the periphery of the trigger part 7, and the spring 5 is tensioned. When injection is performed, the expansion part 62 disengages from the trigger part 7, and the locking block 6 retracts under the rebound action of the spring 5, and drives the locking part 61 to move radially towards the central axis of the drive wheel 2 until it abuts against the annular limiting groove 33, thus completing the axial limiting of the sleeve 3.

[0032] like Figure 11 and 12 As shown, the arc-shaped spring 4 or the locking block 6 is also provided with a supporting part 62. The triggering structure and the supporting part 62 cooperate with each other. When the elastic structure is in a tensioned state, the supporting part 62 abuts against the outer periphery of the triggering structure. At this time, the elastic structure is tensioned and has elastic potential energy, which facilitates automatic recovery during subsequent infusion.

[0033] The triggering structure is a triggering part 7 installed on the housing 81 or reservoir 82 of the fluid delivery mechanism 8. The triggering part 7 is adapted to the expanding part 62 and is used to expand the elastic structure away from the center of the drive wheel 2. The triggering part 7 can be configured as a boss, support plate, or other structural form, and its outer surface can be stably supported by the expanding part 62.

[0034] like Figures 13-15 As shown, in order to ensure the stability of infusion while making the fluid infusion mechanism 8 more integrated, further reducing the number of parts and simplifying assembly, the fluid infusion mechanism 8 of this embodiment omits the independent sleeve 3, so that the central hole 21 of the drive wheel 2 directly engages with the lead screw 1, and the elastic structure is set on the inner wall or end of the hole 21 of the drive wheel 2.

[0035] During initial assembly and fluid filling, the spring structure is in a tensioned state by the trigger part 7. At this time, the engaging part of the spring structure is disengaged from the guide thread 11 of the guide screw 1 and no engagement occurs. Therefore, when the external pressure pushes the plunger in the reservoir 82, the guide screw 1 can freely move axially backward in the hole 21 of the drive wheel 2 to complete the fluid filling. When the drive wheel 2 begins to rotate for injection, the spring structure fixed to the drive wheel 2 rotates accordingly. The opening part 62 of the spring structure quickly disengages from the trigger part 7. After disengagement, the spring structure instantly retracts inward under its own elastic restoring force, entering the released state. The engaging part abuts against the guide thread 11 of the guide screw 1. At this time, since the spring structure is fixedly connected to the drive wheel 2, the rotational torque of the drive wheel 2 is directly transmitted to the spring structure in the engaging state. Because the axial position of the guide screw 1 has been locked in the circumferential direction by the engaging part of the spring structure, according to the transmission principle of the threaded pair, the thread engagement between the rotating spring structure and the stationary guide screw 1 converts the rotational motion of the drive wheel 2 into the axial linear pushing motion of the guide screw 1, thereby pushing the plunger in the reservoir 82 to complete the fluid injection. By eliminating the sleeve 3, the spring structure integrates the functions of axial limiting and transmission, further simplifying the structure, reducing the processing and assembly costs of parts, making the transmission path more direct, and reducing potential transmission errors.

[0036] The above description is illustrative only and not restrictive of the present invention. Those skilled in the art will understand that many modifications, variations or equivalents can be made without departing from the spirit and scope defined by the appended claims, and all such modifications, variations or equivalents will fall within the protection scope of the present invention.

Claims

1. A fluid delivery mechanism, characterized in that: include The lead screw (1) has a lead thread (11) on its outer periphery. The drive wheel (2) has a hole (21) at its center and can rotate around the center of the hole (21). Sleeve (3), the sleeve (3) is provided with internal thread (31), the sleeve (3) is connected to the lead screw (1) through the cooperation of internal thread (31) and lead thread (11), the sleeve (3) passes through the hole (21) of the drive wheel (2), and the sleeve (3) and the drive wheel (2) are configured to have no circumferential relative motion; The drive wheel (2) is provided with an elastic structure, which has a tensioned state and a release state. The outside of the elastic structure is provided with a trigger structure for triggering the elastic structure to switch between the tensioned state and the release state. In the initial state, the elastic structure is in contact with the trigger structure and is in a tensioned state, allowing the lead screw (1) to drive the sleeve (3) to move axially within the hole (21) of the drive wheel (2) for fluid filling; when the elastic structure disengages from the trigger structure, the elastic structure switches from the tensioned state to the release state, restricting the axial movement of the sleeve (3), and the sleeve (3) rotates synchronously with the drive wheel (2), causing the lead screw (1) to advance axially under the cooperation of the internal thread (31) and the guide thread (11) for fluid injection.

2. The fluid delivery mechanism according to claim 1, characterized in that: An anti-rotation structure is provided between the hole (21) of the drive wheel (2) and the sleeve (3) for circumferential positioning of the drive wheel (2) and the sleeve (3); the anti-rotation structure includes a matching convex part and a concave part, one of which is provided on the outer surface of the sleeve (3) and the other is provided on the inner wall of the hole (21) of the drive wheel (2).

3. The fluid delivery mechanism according to claim 2, characterized in that: The protrusion is a strip-shaped protrusion (32) extending axially along the sleeve (3), and the recess is a strip-shaped groove (22) extending axially along the hole (21) of the drive wheel (2). The strip-shaped protrusion (32) and the strip-shaped groove (22) are in clearance fit.

4. A fluid delivery mechanism according to claim 2, characterized in that: The elastic structure includes at least two sets of elastic elements, which are evenly distributed along the circumference of the drive wheel (2).

5. A fluid delivery mechanism according to claim 4, characterized in that: The protrusion or recess is provided at one end of the sleeve (3), and the outer surface of the other end of the sleeve (3) is uniformly arranged with locking parts that are compatible with the elastic element along its axial direction.

6. A fluid delivery mechanism according to claim 5, characterized in that: The elastic element is an arc-shaped spring sheet (4), which has a fixed end (41) and a free end (42). The fixed end (41) is fixedly connected to the drive wheel (2), and the free end (42) extends toward the sleeve (3) and forms a locking part (43).

7. A fluid delivery mechanism according to claim 5, characterized in that: The elastic element includes a spring (5) and a locking block (6). One end of the locking block (6) is movably mounted on the drive wheel (2) via the spring (5) and can be radially displaced relative to the hole (21) of the drive wheel (2). The other end of the locking block (6) extends toward the sleeve (3) and forms a locking part two (61).

8. A fluid delivery mechanism according to claim 7, characterized in that: The drive wheel (2) has multiple mounting blocks (23) corresponding to the locking block (6) on its end face. The multiple mounting blocks (23) are evenly distributed along the circumference of the drive wheel (2). The mounting blocks (23) have guide grooves (24) on them. The locking block (6) is slidably disposed in the guide grooves (24).

9. A fluid delivery mechanism according to claim 6 or 7, characterized in that: The arc-shaped spring (4) or the locking block (6) is also provided with a support part (62). The triggering structure and the support part (62) cooperate with each other. When the elastic structure is in a tensioned state, the support part (62) abuts against the periphery of the triggering structure.

10. A fluid delivery mechanism according to claim 9, characterized in that: The locking part is an annular limiting groove (33) provided on the outer surface of the sleeve (3). The annular limiting groove can also be in the form of a threaded groove or the like. When the elastic structure is in the released state, the first engaging part (43) or the second engaging part (61) engages into the annular limiting groove (33).

11. A fluid delivery mechanism according to claim 9, characterized in that: The triggering structure is a triggering part (7) provided on the housing (81) or reservoir (82) of the fluid delivery mechanism (8), and the triggering part (7) is adapted to the supporting part (62).

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