Screw and nut structure with automatic reciprocating function

Abstract

The invention provides a screw and nut structure with an automatic reciprocating function, which comprises a ratchet wheel sleeve internally provided with a cavity penetrating along the axis; the reverser is rotationally arranged at one end of the ratchet wheel sleeve, a forward rotation internal thread and a reverse rotation internal thread are arranged in the reverser in a segmented mode, and the axis of the forward rotation internal thread and the axis of the reverse rotation internal thread intersect on the axis of the ratchet wheel sleeve; the driving screw rod is movably arranged in the cavity of the ratchet wheel sleeve, the driving screw rod is arranged in the reverser in a penetrating manner, and the outer wall of the driving screw rod is provided with a double-rotation-direction crossed thread; when the reverser is meshed with the driving screw rod, the meshing state comprises meshing of the forward-rotating internal thread and the double-rotating-direction crossed thread or meshing of the reverse-rotating internal thread and the double-rotating-direction crossed thread; the plugs are symmetrically arranged at the two ends of the driving screw, and when the plugs abut against the side wall of the reverser, the reverser rotates to switch the meshing state of the reverser and the driving screw; the device has the effects of simplifying the medicine injection action and achieving automatic and continuous medicine injection.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly relates to a screw - nut structure with an automatic reciprocating function. Background Art

[0002] An insulin pump is a medical device for precisely infusing insulin, and its core function is to simulate the physiological insulin secretion of the human body through continuous or pulsatile drug delivery. The key components of a typical insulin pump include a drug reservoir, a drive system, a control system, and an infusion tube. In the current market, the drive system drives a screw - nut through a motor or a titanium wire ratchet structure to push the piston of the drug reservoir to achieve the drug injection function.

[0003] Regarding the above - mentioned related technologies, in the motor mechanism, an additional commutation circuit and sensor need to be configured, resulting in an increase in the volume of the pump body and making it difficult to meet the portability requirements; in the titanium wire ratchet drive structure, the screw can only move forward unidirectionally without changing the rotation direction of the ratchet. Each time drug injection is required, manual intervention is needed to retract the screw, and the operation is cumbersome and difficult to continue, severely restricting the automation degree and clinical applicability of the insulin pump. Summary of the Invention

[0004] The purpose of the present invention is to provide a screw - nut structure with an automatic reciprocating function to solve the problems of inconvenient drug injection operation and poor drug injection continuity.

[0005] In order to achieve the above purpose, a screw - nut structure with an automatic reciprocating function of the present invention adopts the following technical solutions:

[0006] A screw - nut structure with an automatic reciprocating function, a ratchet sleeve, which is internally provided with a cavity penetrating along the axis;

[0007] A commutator, rotatably arranged at one end of the ratchet sleeve, the commutator rotates around the radial direction of the ratchet sleeve, and the inner part of the commutator is segmented with a positive - rotation internal thread and a reverse - rotation internal thread, and the axis of the positive - rotation internal thread intersects with the axis of the reverse - rotation internal thread on the axis of the ratchet sleeve;

[0008] A driving screw, movably arranged in the cavity of the ratchet sleeve, and the driving screw penetrates through the commutator, and a double - helix cross - thread is arranged on the outer wall of the driving screw;

[0009] When the commutator meshes with the driving screw, the meshing state includes the meshing of the positive - rotation internal thread with the double - helix cross - thread or the meshing of the reverse - rotation internal thread with the double - helix cross - thread;

[0010] The end plugs are symmetrically arranged at both ends of the driving screw. When the end plugs abut against the side wall of the commutator, the commutator rotates to switch the meshing state between the commutator and the driving screw.

[0011] As an optimization of the screw-nut structure with an automatic reciprocating function, a circular convex column is provided at the geometric center of the outer wall of the commutator, and a positioning hole is arranged radially along the inner wall of the ratchet sleeve. The circular convex column is inserted into the positioning hole and rotates therein.

[0012] As an optimization of the screw-nut structure with an automatic reciprocating function, a limiting ball is arranged on the outer wall of the commutator, and two limiting grooves are arranged side by side along the inner wall of the ratchet sleeve. The limiting ball is clamped in one of the limiting grooves.

[0013] As an optimization of the screw-nut structure with an automatic reciprocating function, the axis of the right-handed internal thread is symmetric with respect to the central plane of the commutator to the axis of the left-handed internal thread, and the pitch of the right-handed internal thread is the same as that of the left-handed internal thread.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] (1) Structure simplification and volume optimization: By arranging the right-handed and left-handed internal threads in segments inside the commutator and combining with the double-helix crossed threads of the driving screw, no external commutation circuit or sensor is required, significantly simplifying the structure of the driving system, reducing the volume of the equipment, and meeting the portability requirements of medical devices such as insulin pumps.

[0016] (2) Automatic reciprocating function: Utilizing the thrust of the end plugs at the end of the stroke of the driving screw to trigger the rotation of the commutator to switch the meshing state, realizing the automatic forward and backward movement of the driving screw. This design does not require manual intervention or changing the ratchet rotation direction, significantly improving the continuity and automation degree of the drug injection operation.

[0017] (3) Enhanced operation stability: Through the cooperation of the circular convex column of the commutator and the positioning hole of the ratchet sleeve, as well as the limiting mechanism of the limiting ball and the limiting groove, ensuring the stable rotation center of the commutator, accurate and reliable switching of the meshing state, avoiding disengagement or position jumping, and improving the smoothness of the movement of the driving screw. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1This is the overall structural schematic diagram of the screw-nut structure according to the embodiment of the present application;

[0020] Figure 2 This is the sectional structural schematic diagram of the screw-nut structure according to the embodiment of the present application;

[0021] Figure 3 This is the exploded structural schematic diagram of the screw-nut structure according to the embodiment of the present application.

[0022] In the figure: 1. Ratchet sleeve; 2. Commutator; 21. Right-hand internal thread; 22. Left-hand internal thread; 3. Driving screw; 4. Plug; 5. Circular convex column; 6. Positioning hole; 7. Limiting ball; 8. Limiting groove. Detailed implementation manners

[0023] To make the technical solutions and advantages of the present invention clearer, the present invention and its beneficial effects will be further described in detail below in conjunction with the specific implementation manners and the accompanying drawings of the specification. However, the implementation manners of the present invention are not limited thereto.

[0024] In the description of the present invention, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection", "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0025] The standard parts used in the present invention can all be purchased from the market. The special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, and welding in the existing technology. The machinery, parts, and equipment all adopt conventional models in the existing technology, and the circuit connection adopts the conventional connection method in the existing technology, which will not be elaborated here.

[0026] The following combines the attached Figures 1-3 , and further elaborates on the present application.

[0027] The present application provides a screw-nut structure with an automatic reciprocating function, and adopts the following technical solutions:

[0028] Refer to Figure 1 and Figure 2, the screw-nut structure includes a ratchet sleeve 1, a driving screw 3, a commutator 2, and a plug 4. The ratchet sleeve 1 is in the shape of a cylindrical tube, and a ratchet is integrally formed and sleeved on the outer side of the ratchet sleeve 1. The ratchet is driven by titanium wire and elastic pieces. The ratchet sleeve 1 rotates in a single direction, and a through cavity is provided along the axial direction of the ratchet sleeve 1. The commutator 2 is in the shape of an isosceles trapezoidal prism, and the commutator 2 is embedded and installed inside one end of the ratchet sleeve 1 and rotates around the axis with the ratchet sleeve 1. At the same time, the commutator 2 can rotate around the radial direction of the ratchet sleeve 1, so that the commutator 2 swings and deflects around its geometric center. The inner part of the commutator 2 is segmented with a right-handed internal thread 21 and a left-handed internal thread 22, and the axis of the right-handed internal thread 21 and the axis of the left-handed internal thread 22 are not collinear, and the axis of the right-handed internal thread 21 and the axis of the left-handed internal thread 22 intersect with each other, and the intersection point converges on the axis of the ratchet sleeve 1. In this embodiment, both the right-handed internal thread 21 and the left-handed internal thread 22 are half-threads. During the process of the commutator 2 rotating around the axis with the ratchet sleeve 1, the envelope line of the right-handed internal thread 21 or the left-handed internal thread 22 forms a complete circular thread.

[0029] Referring to Figure 1 and Figure 2 , the driving screw 3 is installed in the cavity of the ratchet sleeve 1, the driving screw 3 moves transversely along the axis of the ratchet sleeve 1, and the driving screw 3 is inserted and installed inside the commutator 2. The outer wall of the driving screw 3 is provided with double-helix cross-threads, and the double-helix cross-threads are composed of a right-handed external thread and a left-handed external thread. Among them, the right-handed external thread matches the right-handed internal thread 21 of the commutator 2, and the left-handed external thread matches the left-handed internal thread 22 of the commutator 2.

[0030] When one section of the internal thread of the commutator 2 is matched with the driving screw 3, the meshing between the commutator 2 and the driving screw 3 can be realized. There are two meshing states. One is that the right-handed internal thread 21 meshes with the double-helix cross-threads, and at this time the driving screw 3 advances along the axis of the ratchet sleeve 1; the other is that the left-handed internal thread 22 meshes with the double-helix cross-threads, and at this time the driving screw 3 retreats along the axis of the ratchet sleeve 1. In any one of the meshing states, the position of the commutator 2 in the axial direction is fixed, the commutator 2 rotates with the ratchet sleeve 1, and the right-handed internal thread 21 or the external rotation internal thread in the commutator 2 rotates around the axis of the ratchet sleeve 1, which is equivalent to a rotating nut; and the driving screw 3 meshes with the commutator 2, and under the drive of the rotating thread, the driving screw 3 moves linearly in the cavity of the ratchet sleeve 1 along the axis of the ratchet sleeve 1. By switching the meshing state, the driving screw 3 moves linearly in the cavity of the ratchet sleeve 1 along the axis of the ratchet sleeve 1 in the reverse direction.

[0031] Referring to Figure 1 and Figure 2The plug 4 has a flange structure, the diameter of the plug 4 is larger than the outer diameter of the driving screw 3, and the plug 4 is symmetrically installed at both ends of the driving screw 3. The plug 4 can be installed at the end of the driving screw 3 by detachable methods such as plugging and bonding, or by first inserting the driving screw 3 into the reversing nut and then welding the plug 4 to both ends of the driving screw 3. This application does not limit its installation method. When the driving screw 3 moves to the end of the stroke in a certain direction, the plug 4 at one end of the driving screw 3 abuts against the side wall of the commutator 2, pushing the commutator 2 to rotate and swing, so that the internal thread on the other side of the commutator 2 contacts the driving screw 3, for example, the forward-rotating internal thread 21 engaged with the driving screw 3 is disengaged, and the reverse-rotating internal thread 22 is engaged with the driving screw 3, thereby realizing the switching of the engagement state. Due to the switching of the rotation direction of the thread, the driving screw 3 is subjected to a reverse driving force and moves in the opposite direction; at the end of each stroke, the plug 4 switches the engagement state by pushing the commutator 2, and so on. Under the premise of not changing the direction of the ratchet wheel, the forward and backward movement of the driving screw 3 can be automatically realized.

[0032] Further, refer to Figure 3 A circular boss 5 is integrally formed at the geometric center of the outer wall of the commutator 2. A positioning hole 6 is radially formed on the inner wall of the ratchet sleeve 1. The circular boss 5 is inserted into the positioning hole 6 and rotates therein. The circular boss 5 stabilizes the rotation center of the commutator 2 at its own geometric center, thereby reducing positional jitter of the commutator 2 during rotation with the ratchet sleeve 1, preventing the commutator 2 from disengaging from the drive screw 3, and improving the tight engagement between the drive screw 3 and the commutator 2, thereby enhancing the stability of the movement of the drive screw 3.

[0033] In the preferred embodiment of the present application, referring to Figure 3 The outer wall of the commutator 2 is provided with a semicircular stopper ball 7. The ratchet sleeve 1 has two corresponding stopper grooves 8 arranged side by side on its inner wall. Each stopper groove 8 has a semicircular cross-section, and a partition wall with a height of only half the radius of the stopper groove 8 is provided between the two stopper grooves 8. The stopper ball 7 engages with one of the stopper grooves 8, limiting the rotation of the commutator 2. One of the stopper grooves 8 corresponds to the engagement of the forward-rotating internal thread 21 in the commutator 2 with the drive screw 3, while the other stopper groove 8 corresponds to the engagement of the reverse-rotating internal thread 21 in the commutator 2 with the drive screw 3. When the commutator 2 is not subjected to the thrust of the plug 4, the limit ball 7 is engaged in one of the limit grooves 8, limiting the rotation of the commutator 2 and maintaining the stable meshing state of the commutator 2 and the drive screw 3 smoothly and reliably; and when the commutator 2 is subjected to the thrust of the plug 4, as the commutator 2 rotates due to the external force, the limit ball 7 passes over the partition wall and enters the adjacent limit groove 8, switching to a limit for another meshing state, thereby improving the stability of the meshing between the drive screw 3 and the commutator 2.

[0034] In the preferred embodiment of the present application, referring toFigure 2 , the axis of the right-handed internal thread 21 is symmetric with the axis of the left-handed internal thread 22 about the central plane of the commutator 2, and the pitch of the right-handed internal thread 21 is the same as that of the left-handed internal thread 22. Specifically, as shown in the figure, the right-handed internal thread 21 and the left-handed internal thread 22 are symmetrically located on both sides of the central plane of the commutator 2 and converge in a conical shape at the geometric center of the commutator 2, so that the movement stroke and accuracy on both sides of the commutator 2 are the same, enabling seamless connection of forward or backward driving and avoiding movement deviation.

[0035] The experimental principle of the embodiment of the present application: The ratchet sleeve 1 drives the commutator 2 to rotate unidirectionally around the axis. The right-handed internal thread 21 or the left-handed internal thread 22 in the commutator 2 meshes with the driving screw 3, so that the driving screw 3 performs forward or backward movement. At the end of the movement stroke of the driving screw 3, during the movement of the plug 4 along with the driving screw 3, it automatically abuts and pushes the commutator 2 to tilt to the other side, enabling the internal thread on the other side to mesh with the driving screw 3 and switching the meshing state. Since the helix direction of the internal thread is reversed, the driving screw 3 moves in the reverse direction. Thus, by repeating this process, without changing the ratchet rotation direction, the forward and backward movement of the screw can be automatically realized. Compared with the traditional scheme that relies on electronic commutation or manual intervention, the present application realizes "unidirectional input, bidirectional output" automatic driving through pure mechanical structure innovation, with the advantages of simple structure, reliable operation, and low cost, simplifies the steps of drug injection operation, and improves the continuity of drug injection.

[0036] According to the disclosure and teaching of the above specification, those skilled in the art of the present invention can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the above specific embodiments. Any obvious improvements, substitutions, or variations made by those skilled in the art based on the present invention fall within the protection scope of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A screw-nut structure with an automatic reciprocating function, characterized in that, It includes a ratchet sleeve (1) with a cavity running through along the axis inside; A commutator (2) is rotatably arranged at one end of the ratchet sleeve (1). The commutator (2) rotates radially around the ratchet sleeve (1). The inside of the commutator (2) is segmented with a right-hand internal thread (21) and a left-hand internal thread (22), and the axis of the right-hand internal thread (21) intersects with the axis of the left-hand internal thread (22) on the axis of the ratchet sleeve (1); A drive screw (3) is movably arranged in the cavity of the ratchet sleeve (1), and the drive screw (3) passes through the commutator (2). A double-threaded cross-thread is arranged on the outer wall of the drive screw (3); When the commutator (2) meshes with the drive screw (3), the meshing state includes the right-hand internal thread (21) meshing with the double-threaded cross-thread or the left-hand internal thread (22) meshing with the double-threaded cross-thread; Plugs (4) are symmetrically arranged at both ends of the drive screw (3). When the plugs (4) abut against the side wall of the commutator (2), the commutator (2) rotates to switch the meshing state between the commutator (2) and the drive screw (3).

2. The screw-nut structure with an automatic reciprocating function according to claim 1, characterized in that, A circular convex column (5) is arranged at the geometric center of the outer wall of the commutator (2), and a positioning hole (6) is arranged radially on the inner wall of the ratchet sleeve (1). The circular convex column (5) is inserted into the positioning hole (6) and rotates; 3. A screw-nut structure with an automatic reciprocating function according to claim 1, characterized in that, A limiting ball (7) is arranged on the outer wall of the commutator (2), and two limiting grooves (8) are arranged side by side on the inner wall of the ratchet sleeve (1). The limiting ball (7) is clamped in one of the limiting grooves (8); 4. A screw-nut structure with an automatic reciprocating function according to claim 1, characterized in that, The axis of the right-hand internal thread (21) is symmetric with respect to the central plane of the commutator (2) to the axis of the left-hand internal thread (22), and the pitch of the right-hand internal thread (21) is the same as that of the left-hand internal thread (22).

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