UNIDIRECTIONAL-DRIVEN DRUG INFUSION DEVICE

Abstract

A unidirectional-driven drug infusion device, includes: a reservoir, a piston and a screw, the piston is arranged in the reservoir; a driving module which includes at least one driving wheel and at least one driving arm that cooperate with each other, the circumferential surface of the driving wheel is provided with wheel teeth; a power module coupled to the driving arm; a control module, connected to the power module, controls the power module to apply different driving powers to the driving arm, making the driving arm perform linear reciprocating motion; and a friction member which is in contact with the surface of the driving wheel. This device can fully utilize the internal space of the infusion device, and its weight and volume is reduced.

Description

TECHNICAL FIELD

The present invention mainly relates to the field of medical instruments, in particular to a unidirectional-driven drug infusion device.

BACKGROUND

A drug infusion device can continuously deliver drug into a patient's body for disease treatment. Drug infusion devices are widely used in the field of diabetes treatment, which continuously infuse required dosage of insulin into the patient's subcutaneous tissue, thereby simulating the secretion function of the pancreas to keep the blood glucose stable. The drug fluid is usually stored inside the infusion pump. The existing drug infusion device, controlled by remote device, is usually attached directly on the patient's skin through a medical adhesive tape.

U.S. Pat. No. 6,656,158 B2 discloses a medicine infusion device, which uses a linearly movable pawl to push gear teeth, thereby realizing medicine infusion. Among them, the infusion device is additionally provided with an anti-reverse fixed pawl to avoid reverse rotation of the driving wheel. Therefore, its internal structure is complicated with lower utilization of the internal space, making the infusion device large and heavy.

Therefore, the prior art urgently needs a unidirectional-driven drug infusion device with higher internal space utilization, lighter weight, and smaller volume.

BRIEF SUMMARY OF THE INVENTION

The embodiment of the invention discloses a unidirectional-driven drug infusion device, which uses a friction member contacting the surface of the driving wheel to prevent the driving wheel from reversing, thereby fully utilizing the internal space of the infusion device, and reducing the weight and volume of the infusion device.

The invention discloses a unidirectional-driven drug infusion device, including: a reservoir, a piston and a screw, the piston, connected with the screw, is arranged in the reservoir; a driving module which includes at least one driving wheel and at least one driving arm that cooperate with each other, the circumferential surface of the driving wheel is provided with wheel teeth which can be pushed to rotate the driving wheel, driving the screw forward; a power module coupled to the driving arm; a control module, connected to the power module, controls the power module to apply different driving powers to the driving arm, making the driving arm perform linear reciprocating motion, driving the driving wheel to rotate; and a friction member which is in contact with the surface of the driving wheel and increases the maximum static friction force received by the driving wheel.

According to one aspect of the present invention, the power applied by the power module to the driving arm includes different linear directions or different magnitudes.

According to one aspect of the present invention, the driving arm includes a variety of different motion amplitudes or a variety of different motion rates.

According to one aspect of the present invention, the power module includes a first power unit and a second power unit respectively connected to the driving arm, and by the action of the power module, the driving arm is controlled to push the wheel teeth in its one motion direction.

According to one aspect of the present invention, the first power unit includes an electrically driven linear actuator or an electrically heated linear actuator while the second power unit includes an electrically driven linear actuator, an electrically heated linear actuator or an elastic member, and the control module controls the frequency or the magnitude of the power exerted by the first power unit and the second power unit, in order to control the motion amplitude or motion rate of the driving arm.

According to one aspect of the present invention, the first power unit is an advancing member while the second power unit is a reset member, during the operation, the advancing member applies power to the driving arm to push the wheel teeth forward, while the reset member applies power to the driving arm to make the driving arm reset.

According to one aspect of the present invention, the driving wheel is a ratchet wheel, the wheel teeth are ratchet teeth, and the driving arm is a pawl which pushes the ratchet teeth to make the ratchet wheel rotate intermittently.

According to one aspect of the present invention, the driving arm includes two driving ends, arranged up and down, whose front ends are not flush, and the two driving ends can alternately push the wheel teeth.

According to one aspect of the present invention, the friction member has elasticity, and the contact position of the friction member with the surface of the driving wheel includes the tooth surface or the non-tooth surface of the driving wheel.

According to one aspect of the present invention, it further includes a base including the friction member, and the driving wheel is movably assembled on the base where the friction member is located, and frictionally fits with the friction member.

According to one aspect of the present invention, the friction member is arranged on the base, and the friction member is frictionally fitted with the side surface of the driving wheel.

Compared with the prior art, the technical solution of the present invention has the following advantages:

In the unidirectional drive medicine infusion device disclosed in the present invention, a control module, connected to the power module, controls the power module to apply different driving powers to the driving arm, making the driving arm perform linear reciprocating motion and driving the driving wheel to rotate. The driving arm with the linearly reciprocating motion has a narrow operating space, which makes the internal structure of the infusion device more compact and reduces the volume of the infusion device. In addition, the infusion device also includes a friction member which is in contact with the surface of the driving wheel and increases the maximum static friction force received by the driving wheel. After the maximum static friction force received by the driving wheel increases, when the driving arm slides on the wheel teeth, the driving wheel does not rotate, which improves the accuracy of drug infusion, eliminates safety hazards, and enhances user experience.

Furthermore, the driving arm includes a variety of different motion amplitudes or a variety of different motion rates. The driving arm with multiple operating modes makes the infusion device have a variety of different infusion modes, therefore, the body fluid level can be precisely controlled, enhancing the user experience.

Furthermore, the first power unit includes an electrically driven linear actuator or an electrically heated linear actuator while the second power unit includes an electrically driven linear actuator, an electrically heated linear actuator or an elastic member. The power output by the linear actuator can be controlled by the current, thus, making the power, the motion amplitude or rate of the driving arm stable and controllable. In addition, the elastic member can reset the driving arm automatically without consuming power, thereby reducing the power consumption of the infusion device.

Furthermore, the driving arm includes two driving ends, arranged up and down, whose front ends are not flush, and the two driving ends can alternately push the wheel teeth. The front ends of the two driving ends are not flush, therefore, the next pushing action can be implemented after the reset distance of the driving arm is less than one tooth pitch, which further reduces the operating space of the driving arm, thus, saving space, and further reducing the size of the infusion device.

Furthermore, the friction member has elasticity, and the contact position of the friction member with the surface of the driving wheel includes the tooth surface and the non-tooth surface of the driving wheel. The elastic friction member can better increase the maximum static friction force. At the same time, the weight of the elastic friction member is much lighter, and its shape, volume, and position setting can be flexibly designed, which not only reduces the weight and volume of the infusion device, but also improves the utilization rate of the internal space of the infusion device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a schematic diagram of a unidirectional-driven drug infusion device according to an embodiment of the present invention;

FIG. 1b-FIG. 1c are top views of two drug infusion devices with multiple infusion modes according to an embodiment of the present invention;

FIG. 2a-FIG. 2b are schematic diagrams of the internal structure of the infusion module according to an embodiment of the present invention, and FIG. 2b is the side view of the driving module in FIG. 2a;

FIG. 3 is a schematic diagram of multiple linear reciprocating motion amplitudes of the driving arm according to an embodiment of the present invention;

FIG. 4a-FIG. 4c are schematic diagrams where the friction member is in contact with the driving wheel in the embodiment of the present invention;

FIG. 5a-FIG. 5c are schematic diagrams s of a driving arm including two driving ends according to another embodiment of the present invention, and FIG. 5b and FIG. 5c are side views of FIG. 5a.

DETAILED DESCRIPTION

As mentioned above, the internal structure design of the drug infusion device in the prior art is complicated with lower utilization of the internal space, making the infusion device large and heavy.

After research, it is found that the cause of the above-mentioned problem is that a fixed pawl is additionally provided inside the infusion device to prevent the reversal rotation of the driving wheel.

In order to solve this problem, the present invention discloses a unidirectional-driven drug infusion device, which uses a friction member frictionally fitted with the driving wheel to prevent the driving wheel from reversing, therefore, fully utilizing the internal space of the infusion device and reducing the size of the infusion device.

Various exemplary embodiments of the present invention will now be described in detail with reference to the drawings. The relative arrangement of the components and the steps, numerical expressions and numerical values set forth in the embodiments are not to be construed as limiting the scope of the invention.

In addition, it should be understood that, for ease of description, the dimensions of the various components shown in the figures are not necessarily drawn in the actual scale relationship, for example, the thickness, width, length or distance of certain units may be exaggerated relative to other structures.

The following description of the exemplary embodiments is merely illustrative, and is not intended to be in any way limiting the invention and its application or use. The techniques, methods and devices that are known to those of ordinary skill in the art may not be discussed in detail, but such techniques, methods and devices should be considered as part of the specification.

It should be noted that similar reference numerals and letters indicate similar items in the following figures. Therefore, once an item is defined or illustrated in a drawing, it will not be discussed further in following description of the drawings.

FIG. 1a is a schematic diagram of a relationship among modules of a unidirectional-driven drug infusion device according to an embodiment of the present invention. FIG. 1b and FIG. 1c are top views of a unidirectional-driven drug infusion device according to two different embodiments of the present invention, respectively.

As shown in FIG. 1a, the control module issues at least an instruction to control the power module to output driving power to the driving module to drive the screw forward, thereby making the infusion device complete drug infusion. For ease of description, the power module, the driving module and the screw are together replaced by infusion module in the following.

Referring to FIG. 1b and FIG. 1c, the unidirectional-driven drug infusion device according to the embodiment of the present invention includes: an adhesive patch 100, a control module 101, an infusion module 102, and an infusion needle 103.

The control module 101 is used to control the driving power output by the power module to control drug infusion. The control module 101 may also establish wireless communication with a remote device (not shown). In one embodiment of the present invention, the control module 101 further includes a power supply (not shown).

The infusion module 102 includes various units for achieving the mechanical function of drug infusion, which will be described in detail below in conjunction with different embodiments.

In the embodiment of the present invention, the control module 101 and the infusion module 102 are designed separately and connected by a waterproof plug. The infusion module 102 can be discarded after a single use, while the control module 101 can be reused, as shown in FIG. 1b. In other embodiments of the present invention, the infusion module 102 and the control module 101, connected by a wire, are disposed inside the same housing 10, and both parts will be discarded together after a single use, as shown in FIG. 1c.

The adhesive patch 100 is used to attach the infusion module 102 or the control module 101, or both of them as a whole on the skin surface.

One end of the infusion needle 103 is connected to the outlet of the infusion module 102, while the other end pierces the skin to infuse the drug subcutaneously. In the embodiment of the present invention, the infusion needle 103 is provided at one end of the infusion module 102. In other embodiments of the present invention, the infusion needle 103 may also be disposed at other positions according to the functions or the structural features of the device, such as being disposed at the middle portion of the infusion device, which is not specifically limited herein. The infusion needle 103 is a rigid infusion needle or a flexible infusion needle, or according to its different positions and functions, the infusion needle 103 can also adopt a combination of a rigid infusion needle(s) and a flexible infusion needle(s), which is not specifically limited herein. Preferably, in the embodiment of the present invention, the infusion needle 103 is a rigid infusion needle.

FIG. 2a-FIG. 2b are schematic diagrams of the internal structure of the infusion module 102 according to an embodiment of the present invention. FIG. 2b is the side view of the driving module in FIG. 2a.

For clearly showing the driving relationship of the driving modules, the power modules are not shown in FIG. 2b.

The internal structure of the infusion module 102 mainly includes a reservoir 110, a piston 120, a screw 130, a driving module and a power module.

The reservoir 110 is used to store drugs which include, but are not limited to, insulin, glucagon, antibiotics, nutrient solutions, analgesics, morphine, anticoagulants, gene therapy drugs, cardiovascular drugs or chemotherapy drugs. Preferably, in this embodiment of the present invention, the drug is insulin.

The piston 120 is used to infuse liquid drug into the body.

The screw 130 is connected to the piston 120, thereby pushing the piston 120 to advance, achieving the purpose of drug infusion. The screw 130 is a rigid screw or a flexible screw. When the screw 130 is a flexible screw, the screw 130 may be designed to be curved. In one embodiment of the invention, the flexible screw is formed by a plurality of threaded sub-units movably connected one by one.

The driving module, used to drive the screw 130 forward, includes at least one driving wheel 140 and at least one driving arm 150 that cooperate with each other. The driving wheel 140, the circumferential surface of which is provided with wheel teeth 141, is connected to the screw 130.

Here, the cooperation means that when the driving arm 150 operates in a certain manner or mode, the driving wheel 140 will implement an associated operating manner or mode to achieve the goal of driving the screw 130 forward and completing the drug infusion.

It should to be noted here that the operating manner and operating mode belong to different technical concepts. The operating manner refers to the specific working method or working form, such as unidirectional reciprocating motion, of the driving arm 150. However, the operating mode represents the effect, such as the change of the motion amplitude or the motion rate, brought about by the operating manner of the driving arm 150.

As in this embodiment of the present invention, the driving arm 150 can perform linear reciprocating motion in the L direction shown in FIG. 2a and FIG. 2b. Preferably, the driving arm 150 is a pawl while the driving wheel 140 is a ratchet which can be more easily pushed, therefore, the wheel teeth 141 are ratchet teeth. As in another embodiment of the present invention, the driving wheel 140 is an ordinary mechanical gear. Compared with the driving arm 150 operating in a rotary reciprocating motion, the linear reciprocating motion can save its operating space, making the internal structure of the infusion device more compact, and reducing the volume of the infusion device.

Obviously, since the driving arm 150 is a driving structure while the driving wheel 140 is a driven structure, the power module is coupled with the driving arm 150 and outputs driving power to it. In this way, the driving arm 150 can perform linear reciprocating motion, and it will have a variety of different operating modes as well, such as different reciprocating motion amplitude or motion rate. The coupling method between the power module and the driving arm 150 includes mechanical connection or electrical connection.

Preferably, in the embodiment of the present invention, the power module includes a first power unit and a second power unit which are electrically or mechanically connected to and apply driving power to the driving arm 150, respectively. Preferably, in the embodiment of the present invention, the first power unit is an advancing member 180 while the second power unit is a reset member 170, as shown in FIG. 2a. The advancing member 180 applies power to the driving arm 150, thereby pushing the wheel teeth 141 to rotate the driving wheel 140, and realizing drug infusion. The reset member 170 applies power to the driving arm 150 which will reset and slide on the wheel teeth surface without pushing the wheel teeth 141, therefore, the driving wheel 140 does not rotate.

The reset member 170 includes an electrically driven linear actuator, an electrically heated linear actuator, or an elastic member that can automatically reset the driving arm 150 without using an external power. The type of elastic members includes, but is not limited to, at least one compression spring, extension spring, torsion spring, elastic sheet, elastic plate, elastic rod, elastic rubber, and the like. Preferably, in the embodiment of the present invention, the reset member 170 is a torsion spring which is more conducive to reset the driving arm 150.

In another embodiment of the present invention, the reset member 170 is an electrically driven linear actuator or an electrically heated linear actuator, such as a shape memory alloy. After being energized, the physical form of the material of the linear actuator changes, which makes it shrinkage deformation, thereby outputting driving power. The higher the current is, the larger shrinkage deformation is, and the greater the driving power outputs. Obviously, when the current is constant, the driving power output by the linear actuator is constant. Therefore, the linear actuator can output a stable and controllable driving power, which makes the infusion process stable and controllable, enhancing the user experience.

The advancing member 180, an electrically driven linear actuator or an electrically heated linear actuator, directly applies driving power to the driving arm 150. Preferably, in the embodiment of the present invention, the advancing member 180 is a shape memory alloy.

As shown in FIG. 2a, the principle of the driving arm 150 driving the driving wheel 140 to rotate in the embodiment of the present invention is as follows. When the control module controls the advancing member 180 to pull the driving arm 150 by force F_P, the driving arm 150 advances in L₁ direction, driving the driving end 151 to push the wheel teeth 141 forward, thereby rotating the driving wheel 140, which makes the screw 130 advance in the D_A direction and makes the infusion device perform drug infusion. At this time, the reset member 170 is an elastic member which builds a gradually increasing elastic force F_R. When the advancing member 180 stops applying force and under the action of the elastic force F_R, the driving arm 150 resets in L₂ direction. And the driving end 151 stops pushing the wheel teeth 141, therefore the driving wheel 140 stops rotating, and the screw 130 stops advancing, so that the infusion device does not proceed drug infusion. The driving end 151 will slide on the surface of the wheel teeth 141 for reset until the driving arm 150 stops motion. After these above two motions, the driving arm 150 completes one linear reciprocating motion L.

By analogy, the driving arm 150 can complete multiple linear reciprocating motions. Obviously, when the infusion device of the embodiment of the present invention is in operation, the rotating manner of the driving wheel 140 is intermittent rotation, that is, a manner of rotation-stop-rotation-stop—. . . .

FIG. 3 is a schematic diagram of multiple linear reciprocating motion amplitudes of the driving arm 150 according to an embodiment of the present invention.

When the power received by the driving arm 150 is different, its motion rate or motion amplitude will be different. Therefore, the principle of the driving arm 150 implementing two linear reciprocating motion amplitudes according to the embodiment of the present invention is as follows. The control module controls the power magnitude output by the advancing member 180, while the reset member 170 implements resetting function, which makes the driving arm 150 perform linear reciprocating motion and makes the driving end 151 advance or reset. E_n represents the position reached by the front end of the driving end 151, such as E₁, E₂, E₃, E₄, E₅. h_n represents the distance between two different positions E_n. S_n represents the different positions of the point S of the power output by the advancing member 180 during the linear reciprocating motion, and the dotted arc in FIG. 3 represents the trajectory of S, therefore, S₁, S₂, S₃, S₄, S₅ corresponds with E₁, E₂, E₃, E₄, E₅, respectively. Obviously, the motion distance between different S_n can be used to represent the motion amplitude of the driving arm 150. Preferably, in the embodiment of the present invention, h₁ is the pitch of wheel tooth, and h₁=3h₂. When the advancing member 180, according to the instruction from the control module, makes the driving end 151 to push the wheel teeth 141 from the E₁ to the E₂ position, the advancing member 180 stops outputting power, and the reset member 170 starts to work until resetting the driving end 151 to the E₃ position, which makes the driving arm 150 complete the first linear reciprocating motion. The motion amplitude of the driving arm 150 is S₁-S₂ and S₂-S₃. During the first linear reciprocating motion, the front end of the driving end 151 pushes a tooth forward by a distance h₁, the drug infusion volume is V₁, and its reset distance is h₃. At this time, the infusion volume V₁ is regarded as the infusion increment in this first infusion mode. When the next driving is performed, the advancing member 180 outputs power. During the advancing distance h₃ of the driving end 151, the driving wheel 140 does not rotate, nor does the drug infusion perform. When the front end of the driving end 151 reaches the E₂ position and continues to advance by a distance of h₄, the front end of the driving end 151 pushes the wheel teeth 141 to the E₄ position, the driving wheel 140 rotates, implementing the drug infusion. When the advancing member 180 stops outputting power, the reset member 170 resets the driving end 151 to, such as, the E₅ position, therefore, the driving arm 150 completes the second linear reciprocating motion, and the driving arm 150 moves by S₃-S₄ and S₄-S₅. During the second linear reciprocating motion, the forward distance of the front end of the driving end 151 is (h₃+h₄), and the drug infusion volume is V₂. At this time, the infusion volume V₂ is the infusion increment in this second infusion mode. Obviously, the driving arm 150 only drives the driving wheel 140 to rotate under the motion amplitudes S₁-S₂ and S₂-S₄ in these two infusion modes. For the motion amplitude S₁-S₂ is greater than the motion amplitude S₂-S₄ (or h₁>h₄), V₁>V₂. Therefore, the infusion device of the embodiment of the present invention has two different infusion increments.

By analogy, the distance between E₁, E₂, E₃, E₄, E₅ can be arbitrarily selected, such as h₁=h₂, h₁=2h₂, h₁=4h₂, etc., the infusion device has a variety of different infusion increments. Or the force point S can also reaches to the S₆ position, and S₄ and S₆ may not be the limit positions for the moving of the driving arm 150, which is not specifically limited herein.

It should be noted that, as described above, in the embodiment of the present invention, the infusion device does not necessarily implement drug infusion when the driving end 151 advances. Only when the driving end 151 pushes the wheel teeth 141 forward, the infusion device does.

Each amplitude of the linear reciprocating motion of the driving arm 150 corresponds with an infusion increment. Therefore, a variety of different motion amplitudes of the driving arm 150 make the drug infusion device have a variety of different infusion increments. Taking insulin as an example, the infusion increment range of the drug infusion device in the embodiment of the present invention is 0.0005 U˜0.25 U (here, the infusion increment range includes endpoint values, that is, the infusion increment includes 0.0005 U and 0.25 U). In some embodiments of the present invention, the infusion increment of the drug infusion device may includes 0.001 U, 0.0025 U, 0.005 U, 0.0075 U, 0.01 U, 0.025 U, 0.05 U, 0.075 U, 0.1 U, etc. Preferably, in the embodiment of the present invention, the infusion increment of the drug infusion device includes 0.005 U, 0.0075 U, 0.01 U, 0.025 U, and 0.05 U.

It should be noted here that when h₁=h₂, the infusion increment of the infusion device always maintains V₁ with the motion amplitude of the driving arm 150 always maintaining S₁-S₂ and S₂-S₁, which makes the infusion relatively stable.

Another embodiment of the present invention can also increase the frequency of the power output by the advancing member 180 to increase the frequency of the linear reciprocating motion of the driving arm 150, thereby increasing the infusion rate. Therefore, the infusion devices in the embodiments of the present invention can all change the power magnitudes to make them have multiple infusion rates.

Here, the change of the power magnitudes can change the rate of the unidirectional motion, the rate of reciprocating motion, or the frequency of reciprocating motion.

When the drug infusion device has multiple infusion modes, the user, according to the actual requirements, can flexibly select the infusion mode to stabilize the level of body fluid parameters. Taking insulin stabilizing blood glucose levels as an example, some users or body tissues at the infusion site absorb insulin slowly. Users can choose a infusion mode with smaller infusion increment or lower infusion rate, which not only stabilizes the blood glucose level, but also improves the utilization of insulin, reducing the burden on body tissues. As another example, blood glucose spikes after a meal, so the user can first select an infusion mode with a relatively large infusion increment or a relatively high infusion rate to suppress the rapid rise in blood glucose, and then select an infusion mode with a medium infusion increment or infusion rate, and finally, choose an infusion mode with a relatively small infusion increment or a relatively low infusion rate to slowly stabilize blood glucose at a reasonable level. For another example, the bolus insulin required after each meal is different, and the body's basal insulin requirement is also different at different periods of one day. Therefore, multiple infusion modes of the infusion device can be flexibly selected (by the user or automatically by the closed-loop system) according to the actual requirements to achieve the goal of precise control of blood glucose levels.

FIG. 4a-FIG. 4c are schematic diagrams where the friction member 191 is in contact with the driving wheel 140 in the embodiment of the present invention.

The motion of the driving wheel 140 can directly drive the screw to advance for drug infusion. Therefore, when the driving arm 150 does not push the wheel teeth 141, the driving wheel 140 should stop rotating. Otherwise, there will be inaccurate drug infusion and safety risks.

Conventionally, the pawl should have a certain elasticity to ensure that the ratchet wheel can be continuously pushed. Therefore, in the embodiment of the present invention, when the driving end 151 slides on the surface of the wheel teeth 141, the curved driving end 151 contacts the wheel teeth 141 with exerting a certain pressure to the driving wheel 140. Obviously, due to the structural characteristics of the wheel teeth 141 and the circumference of the driving wheel 140, the foresaid pressure applied by the driving end 151 is not equal at different positions. Therefore, when the driving end 151 slides (in the reset motion, or just only slides forward without pushing the wheel teeth 141) on the surface of the wheel teeth 141, there is a possibility of forward rotation or reverse rotation of the driving wheel 140. If such rotations occur, the accuracy of drug infusion will be reduced, bringing safety risks. Therefore, the embodiment of the present invention also includes a friction member 191, which is in contact with the surface of the driving wheel 140 to increase the maximum static friction force received by the driving wheel 140 in order to ensure that when the driving arm 150 slides on the teeth surface, the driving wheel 140 will not rotate, avoiding bringing security risks to users.

It should be noted that, compared with the aforementioned pushing force exerted by the driving arm 150 to advance the wheel teeth 141, this pressure exerted by the curved driving arm 150 to the driving wheel 140 is much smaller. Therefore, the existence of the friction member 191 does not affect the actual pushing of the driving arm 150, that is, does not affect the drug infusion.

Other embodiments of the present invention do not limit the position of the friction fit, as long as the condition for increasing the maximum static friction force received by the driving wheel 140 can be satisfied. The embodiment of the present invention also does not limit the material of the friction member 191, for example, the friction member 191 is an elastic component, a plastic component, or a metal component. Preferably, the friction member 191 has elasticity, such as silica gel.

Here, the friction fit means that a certain pressure is preset between the two structures to generate friction. The following friction fit has the same meaning as here.

Preferably, in the embodiment of the present invention, the contact position of the friction member 191 with the surface of the driving wheel 140 is located on the non-tooth surface of the driving wheel 140. As in an embodiment of the present invention, the infusion device further includes a base 190 where the driving wheel 140 is movably assembled. At this time, the friction member 191 is a part of the base 190. In the embodiment of the present invention, the friction member 191 is located at the position where the driving wheel 140 and the base 190 are movably assembled, as shown in the dashed frame A in FIG. 4a.

As shown in FIG. 4b, in another embodiment of the present invention, the friction member 191 is disposed on the base 190. The position where the friction member 191 is frictionally fitted with the driving wheel 140 is at position B or position C (the side surface of the driving wheel 140, as shown by the dashed frame).

As shown in FIG. 4c, the friction member 191 can also be in contact with the tooth surface of the driving wheel 140, which can also increase the maximum static friction force received by the driving wheel 140.

In an infusion device, a single pawl pushes the gear to rotate for the drug infusion. However, conventional pawl pushing generally requires an additional anti-reverse fixed pawl, or two opposed pawls to be used in conjunction to ensure that the gear does not rotate in the reverse direction. At this time, the number of pawls in the infusion device is large, resulting in much more complicated design and lower space utilization rate.

In the infusion device disclosed in this present invention, there is no need to additionally provide an anti-reversal pawl, but a friction member is used instead. And the friction member presses the surface of the driving wheel, increasing the maximum static friction force received by the driving wheel, which is different from the function of the anti-reversal pawl. At the same time, the volume, shape, and location of the friction member can be flexibly designed according to the internal space of the infusion device, making full use of the internal space and effectively reducing the volume of the infusion device. In addition, compared with the anti-reversal pawl, the weight of the friction member is lighter, thus, reducing the weight of the infusion device and enhancing the user experience.

FIG. 5a-FIG. 5c are schematic diagrams s of a driving arm 250 including two driving ends 251a and 251b according to another embodiment of the present invention. FIG. 5b and FIG. 5c are side views of FIG. 5a.

It should be noted that, in order to clearly show the structural relationship between the driving arm 250 and the driving wheel 240, the power module is not shown in FIG. 5a-FIG. 5c, which is similar to the aforementioned.

In another embodiment of the present invention, the driving arm 250 includes two driving ends 251a and 251b which are arranged up and down. The front ends of the two driving ends are not flush with a distance m, as shown in FIG. 5b.

Here, the up and down arrangement means that when the driving arm 250 is viewed from its top, the driving end 251a partially shields 251b, as shown in FIG. 5a. While the driving arm 250 is viewed from its side, the driving end 251a and 251b will be both shown, as shown in FIG. 5b.

Preferably, in the embodiment of the present invention, if the tooth pitch is T, then m=T/n(n>1). Therefore, when the driving arm 250 is reset to a distance less than one tooth pitch T, the next pushing action can be started, which further reduces the motion space of the driving arm 250. Preferably, m=T/2. At this time, the driving ends 251a and 251b of the two driving arms can alternately push the wheel teeth 241. Each time when the driving arm 250 is reset by a distance of T/2, the next pushing action can be started, as shown in FIG. 5b and FIG. 5c.

Obviously, the power module of the embodiment of the present invention can also apply different powers to the driving arm 250, making the driving arm have a variety of different motion modes, as described above. Moreover, it is also possible to only use the driving end 251a or 251b to individually push the wheel teeth 241 to rotate the driving wheel 240, advancing the screw 230.

In other embodiments of the present invention, m=(3T)/2, or the driving arm may also include more than two driving ends which can also alternately push the wheel teeth. Or the infusion device includes more than one driving arm, which is not specifically limited, as long as it can meet the conditions for pushing the driving wheel to rotate.

In summary, the invention discloses a unidirectional-driven drug infusion device, which uses a friction member contacting the surface of the driving wheel to prevent the driving wheel from reversing, fully utilizing the internal space of the infusion device, and reducing the weight and the volume of the infusion device.

While the invention has been described in detail with reference to the specific embodiments of the present invention, it should be understood that it will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A unidirectional-driven drug infusion device, includes: a reservoir, a piston and a screw, wherein the piston, connected with the screw, is arranged in the reservoir;a driving module which includes at least one driving wheel and at least one driving arm that cooperate with each other, a circumferential surface of the driving wheel is provided with wheel teeth which can be pushed to rotate the driving wheel, driving the screw forward;a power module coupled to the at least one driving arm;a control module, connected to the power module, controls the power module to apply different driving powers to the driving arm, making the driving arm perform linear reciprocating motion, thus, driving the driving wheel to rotate; anda friction member which is in contact with the surface of the driving wheel and increases the maximum static friction force received by the driving wheel.

2. The unidirectional-driven drug infusion device of claim 1, wherein the different driving powers applied by the power module to the driving arm includes different linear directions or different magnitudes.

3. The unidirectional-driven drug infusion device of claim 2, wherein the driving arm includes a variety of different motion amplitudes or a variety of different motion rates.

4. The unidirectional-driven drug infusion device of claim 3, wherein the power module includes a first power unit and a second power unit respectively connected to the driving arm, and by the action of the power module, the driving arm is controlled to push the wheel teeth in its only one motion direction.

5. The unidirectional-driven drug infusion device of claim 4, wherein the first power unit includes an electrically driven linear actuator or an electrically heated linear actuator while the second power unit includes an electrically driven linear actuator, an electrically heated linear actuator or an elastic member, and the control module controls the frequency or the magnitude of the power exerted by the first power unit and the second power unit, in order to control the motion amplitude or motion rate of the driving arm.

6. The unidirectional-driven drug infusion device of claim 5, wherein the first power unit is an advancing member while the second power unit is a reset member, during the operation, the advancing member applies power to the driving arm to push the wheel teeth forward, while the reset member applies power to the driving arm to make the driving arm reset.

7. The unidirectional-driven drug infusion device of claim 1, wherein the driving wheel is a ratchet wheel, the wheel teeth are ratchet teeth, the driving arm is a pawl which pushes the ratchet teeth to make the ratchet wheel rotate intermittently.

8. The unidirectional-driven drug infusion device of claim 1, wherein the driving arm includes two driving ends, arranged up and down, whose front ends are not flush, and the two driving ends can alternately push the wheel teeth.

9. The unidirectional-driven drug infusion device of claim 1, wherein the friction member has elasticity, and the contact position of the friction member with the surface of the driving wheel includes the tooth surface or the non-tooth surface of the driving wheel.

10. The unidirectional-driven drug infusion device of claim 9, wherein the unidirectional-driven drug infusion device further includes a base which includes the friction member, and the driving wheel is movably assembled on the base where the friction member is located and frictionally fits with the friction member.

11. The unidirectional-driven drug infusion device of claim 10, wherein the friction member is arranged on the base, and the friction member is frictionally fitted with the side surface of the driving wheel.