Reusable motorized auto-injection device

Abstract

A reusable motorized auto-injection device includes a housing; a single motor within said housing; a drive shaft configured to move linearly; a sleeve configured to receive a syringe containing a medication; and a circuit switcher, wherein said drive shaft is configured to engage a stopper of said syringe, and wherein said circuit switcher is configured to automatically cause said motor to operate in a first mode and in a second mode successively with the linear movement of said drive shaft, wherein in said first mode, said motor is connected to a first circuit such that said drive shaft is linearly moved at a first, faster speed, thereby realizing rapid insertion of a needle of said syringe, and wherein in said second mode, said motor is connected to a second circuit such that said drive shaft is linearly moved at a second, slower speed, thereby realizing a slow infusion of medication.

Description

REUSABLE MOTORIZED AUTO-INJECTION DEVICECROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to Chinese Patent Application No. 202311118494.9 entitled “Reusable Motorized Auto-Injection Device” filed August 31, 2023, the disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTIONField of the Invention

[0002] The present disclosure relates to an injection device for delivering a dose of a medication from a syringe, and in particular to a reusable motorized auto-injection device, such as an auto-injection pen.Description of Related Art

[0003] Auto-injection devices such as auto-injection pens are widely used because they make medication injection easier and more convenient. Each time a medication is injected, a user simply opens the injection pen, loads a syringe or cartridge, and then activates a switch for automatic needle feeding and automatic infusion of the medication.

[0004] Typically, prior art auto-injection pens require independent implementation of both needle insertion and medication infusion motions. The two motions have different objects and different speeds, so two sets of motion mechanisms are typically required to realize the two motions for the needle and the medication, respectively. For example, two springs, or one spring and one motor, or two motors are used to realize the respective motions of the needle and the medication, respectively.

[0005] For example, CN110650761B discloses a self-injector comprising a plunger engaged with a stopper, a cannula surrounding the plunger, an insertion spring that biases the cannula with respect to the rear of the device, and a delivery spring that biases the plunger with respect to the cannula. The insertion spring is used to insert the needle into a patient and the delivery spring is used to infuse medication.

[0006] As another example, CN1665557A discloses a medical automatic medication delivery device having two motors. By operating a switching mechanism provided on the body, a firstmotor is activated to automatically cause an injection needle housed in the body to protrude from the body for carrying out feeding of the needle to the injection site, and then a second motor is activated to push the medication to infuse the medication into a patient.

[0007] The use of two sets of motion mechanisms results in a complex and bulky structure of the entire injection device and an increased risk of failure. In addition, the use of two motors increases the complexity of wiring and raises costs.SUMMARY OF THE INVENTION

[0008] Accordingly, it is an object of the present disclosure to provide a reusable motorized auto-injection device which is capable of solving at least one of the above technical problems existing in the prior art. In particular, the motorized auto-injection device of the present disclosure is capable of simplifying the structure, reducing the cost, and being easy to miniaturize.

[0009] The reusable motorized auto-injection device of the present disclosure uses a single motor to realize two motions of needle insertion and medication infusion. The speeds of the two motions are automatically realized by circuit switching, whereby the device automatically switches from one circuit to another circuit during operation, thereby causing the motor to operate at different speeds.

[0010] Further, the switching of motor speed combined with a sleeve achieves the switching of two moving objects simultaneously.

[0011] A reusable motorized auto-injection device comprises: a housing; a single motor being housed within said housing; a drive shaft configured to be driven by said motor to move linearly; a sleeve configured to receive a syringe containing a medication; and a circuit switcher, wherein said drive shaft is configured to be able to engage a stopper of said syringe so as to push said stopper, and wherein said circuit switcher is configured to be able to automatically cause said motor to operate in a first mode and in a second mode successively with the linear movement of said drive shaft, wherein in said first mode, said motor is connected to a first circuit such that said drive shaft is linearly moved at a first, faster speed, thereby realizing rapid insertion of a needle of said syringe, and wherein in said second mode, said motor is connected to a second circuit such that said drive shaft is linearly moved at a second, slower speed, therebyrealizing a slow infusion of medication from said syringe. In this way, the auto-injection device according to this present disclosure automatically achieves the speeds of the two motions mentioned above by circuit switching.

[0012] Preferably, said circuit switcher comprises a first conductor disposed in said first circuit, a second conductor disposed in said second circuit, and a movable contact, said movable contact being configured to be capable of moving successively over said first conductor and over said second conductor in electrical contact.

[0013] Preferably, said first conductor and said second conductor are arranged in close proximity to each other in a line, but electrically isolated. The expression “electrically isolated” herein means electrically separated, i.e., electrically insulated or not electrically connected.

[0014] Preferably, said first conductor and / or said second conductor are in the form of a sheet of metal. Said sheet of metal may be a sheet of copper, aluminum, iron, steel, or any other electrically conductive material.

[0015] Preferably, said movable contact is attached to said drive shaft and is capable of moving linearly with said drive shaft, said movable contact being configured to initially come into electrical contact with said first conductor, whereby said motor is connected to said first circuit and thus operates in said first mode; as said drive shaft is moved linearly, said movable contact is disengaged from electrical contact with said first conductor and is then brought into electrical contact with said second conductor, such that said motor is switched to be connected to said second circuit, thereby operating in said second mode. In this regard, a length of said first conductor or a distance traveled by said movable contact on said first conductor corresponds substantially to a distance traveled rapidly by the needle of the syringe, and a length of said second conductor or a distance traveled by said movable contact on said second conductor corresponds substantially to a distance traveled slowly by the stopper of the syringe.

[0016] Preferably, the current supplied to said motor by said first circuit when energized is less than the current supplied to said motor by said second circuit when energized.

[0017] Preferably, said motor is powered by a power source which is shared by said first circuit and said second circuit.

[0018] Preferably, an additional resistor is added to said second circuit compared to said first circuit, thereby enabling said motor to be supplied with a smaller current. That is, the circuitswitcher is utilized to switch to another circuit with the additional resistor during linear movement of the drive shaft. During the initial linear movement, the circuit has a lower resistance, thereby allowing a faster linear movement. When the circuit is switched to the higher resistance circuit, the linear movement slows down. This may be referred to as a dual speed scheme using dual resistor circuits.

[0019] Optionally, a resistance value of said resistor is adjustable. This gives the user the flexibility to adjust the speed of medication infusion according to the different requirements of the medication infusion.

[0020] Alternatively, said power source is a first power source, said first circuit additionally has a second power source as compared to said second circuit, said first power source and said second power source are connected in series, whereby both said first power source and said second power source together supply power to said motor when said motor is connected to said first circuit; and power is supplied to said motor only by said first power source when said motor is connected to said second circuit. That is, the circuit switcher is utilized to switch a circuit with two power sources in series to another circuit with a single power source. During the initial linear movement of the drive shaft, the circuit has two power sources in series, which will result in a faster linear movement. When the circuit is switched to a single-supply-source circuit, the linear movement slows down. This may be referred to as a dual speed scheme with dual voltage circuits.

[0021] Preferably, said first circuit starts at said motor and connects in series said first power source, said movable contact, said first conductor, said second power source, and then back to said motor, forming a closed circuit. Said second circuit starts at said motor and connects in series said first power source, said movable contact, said second conductor, a short-circuit proof resistor, and then returns to said motor, forming another closed circuit. Said short-circuit proof resistor is connected in series between said second conductor and said motor. In this manner, it is possible to prevent transient short-circuiting of the second power source which may occur when the movable contact moves to the junction between the first conductor and the second conductor due to the possibility of it contacting both the first conductor and the second conductor at the same time. The main purpose of the short-circuit proof resistor herein is toprevent transient short-circuiting, and therefore a resistor having a smaller resistance value may be selected.

[0022] Optionally, a resistance value of said short-circuit proof resistor is adjustable. In this way, the user can flexibly adjust the speed of medication infusion according to different requirements of medication infusion.

[0023] Preferably, on an inner wall of said housing is provided a proximal stop which defines a most proximal position of said sleeve.

[0024] Preferably, said reusable motorized auto-injection device further comprises a distal stop provided distal to a distal end of said sleeve and spaced apart from said distal end, said distance determining a depth of insertion of a needle of said syringe.

[0025] Preferably, said reusable motorized auto-injection device further comprises a reset spring surrounding said sleeve, one end of said reset spring resting against said distal stop and the other end resting against an outwardly extending proximal protrusion of said sleeve. This allows the reset spring to reset the sleeve for re-use after the infusion is finished.

[0026] Preferably, said distal stop comprises a U-shaped body with a bottom wall being formed with a through hole for free passage of said syringe. In this way, the rapid linear movement of the drive shaft when the motor is operating in the first mode is able to move both the sleeve and the syringe as a whole (overcoming the biasing force of the reset spring), thereby driving the needle of the syringe rapidly into the patient.

[0027] Preferably, a tab for the user's finger to pinch is formed at a distal end of each of two sidewalls of said U-shaped body, said tab being configured to be able to move along a slit in said housing in order to adjust said distance. This allows the user to flexibly adjust the depth of insertion of the needle according to the different requirements of the medication infusion as well as the different sites of infusion.

[0028] Preferably, said distal stop further comprises a pawl or outer tooth formed on each of said two sidewalls of said U-shaped body and a plurality of inner teeth disposed opposite to said pawl or outer tooth, said pawl or outer tooth being configured to selectively engage a corresponding tooth of said plurality of inner teeth in order to fix said distance. Optionally, said plurality of inner teeth are formed on an inner wall of said housing.

[0029] Preferably, said motor is a linear motor, said linear motor directly driving said drive shaft.

[0030] Preferably, said motor is a rotary motor, said rotary motor driving said drive shaft via a motion conversion mechanism, said motion conversion mechanism being configured to convert a rotary motion of said rotary motor into a linear movement of said drive shaft.

[0031] Preferably, said motion conversion mechanism comprises an outer sleeve with a female thread and an inner shaft with a male thread, said female thread configured to engage said male thread.

[0032] Preferably, said drive shaft is provided with a slider, said slider configured to non- rotationally, linearly move said drive shaft.

[0033] Preferably, said slider is configured to move along a linear track, said linear track being provided within said housing.

[0034] Optionally, said movable contact is attached to said slider. Optionally, said movable contact is attached to said slider by means of an L- shaped arm.

[0035] Preferably, in addition to said motor, said drive shaft, said sleeve, and said circuit switcher can be also housed within said housing, thereby forming an integrated structure.

[0036] The main advantage of the reusable motorized auto-injection device of the present disclosure over the prior art is that there is only one set of mechanical drive mechanism, i.e., the drive shaft and the motor circuit. Having only one set of drive mechanism improves the reliability and reduces the cost of the auto-injection device.

[0037] The reusable motorized auto-injection device of the present disclosure can be applied to many auto-injection devices, such as Epipen, BD Physioect™ disposable autoinjector, Aria smart autoinjector, and so on.

[0038] Other purposes, features, and details of the present disclosure may be more fully understood with reference to the following detailed description of exemplary embodiments and in conjunction with the accompanying drawings and in accordance with the accompanying claims.

[0039] A person skilled in the art will understand advantages of corresponding embodiments and various additional embodiments by reading the following detailed description of the corresponding embodiments with reference to the drawings as listed below. In addition,features in the drawings discussed below are not necessarily drawn to scale. Sizes of the features and elements in the drawings may be appropriately enlarged or reduced to more clearly illustrate the embodiments of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present disclosure is further described below in connection with the accompanying drawings and embodiments, wherein the same reference marks refer to similar or identical elements throughout the accompanying drawings and their description.

[0041] FIG. 1 is a perspective view of a reusable motorized auto-injection device according to an embodiment of the present disclosure.

[0042] FIG. 2 is a detail view of a portion of a reusable motorized auto-injection device according to the embodiment of the present disclosure, showing in particular a slider, a linear track, an L- shaped contact arm, a movable contact, a first conductor, a second conductor, and a portion of a sleeve and a reset spring.

[0043] FIG. 3 is a schematic view of an exemplary syringe that can be loaded into a reusable motorized auto-injection device of the present disclosure.

[0044] FIG. 4 is a partially enlarged view of a reusable motorized auto-injection device according to the embodiment of the present disclosure, showing in particular a distal stop, a reset spring, a sleeve, and a syringe.

[0045] FIG. 5 is a schematic diagram of a reusable motorized auto-injection device according to an embodiment of the present disclosure, showing a first circuit and a second circuit in a dual resistor circuit scheme.

[0046] FIG. 6 is a schematic diagram of a reusable motorized auto-injection device according to another embodiment of the present disclosure, showing a first circuit and a second circuit in a dual voltage circuit scheme.DESCRIPTION OF THE INVENTION

[0047] Various illustrative embodiments of the present disclosure are described below. In this description, for the sake of explanation only, various systems, structures and devices are schematically depicted in the drawings, but all the features of actual systems, structures anddevices are not described. For example, well-known functions or structures are not described in detail to avoid unnecessary details to obscure the present disclosure. Of course, it should be understood that in any practical application, many specific implementation decisions need to be made to achieve the specific goals of the developer or user, and the system-related and industry-related restrictions need to be observed. These specific goals may vary with actual applications. In addition, it should be understood that although such specific implementation decisions are complicated and time-consuming, this is a routine task for those of ordinary skill in the art who benefit from the present application.

[0048] The terms and phrases used herein should be understood and interpreted as having a meaning consistent with the understanding of those terms and phrases by those skilled in the relevant art. The consistent usage of terms or phrases herein is not intended to imply a specific definition of the term or phrase, that is, a definition that differs from the ordinary and customary meanings understood by those skilled in the art. For terms or phrases intended to have a special meaning, that is, meanings different from those understood by the skilled person, this special meanings will be clearly listed in the description by definition, giving special meanings to the term or phrase directly and unambiguously.

[0049] Unless the content requires, throughout the following description and claims, the words "comprising" and its variations, such as "including", will be interpreted in an open and inclusive sense, that is, as "comprising but not limited to".

[0050] In the description of this disclosure, singular forms of "a", “an”, and "the" include plural objects of discussion, unless the context clearly indicates to the contrary; an individually existing feature without quantity limitations can explicitly or implicitly include one or more of such feature. The meaning of "a plurality of" refers to two or more, unless otherwise specified.

[0051] In the present disclosure, the terms "first", "second", and the like are used for descriptive purposes only and cannot be construed as indicating relative importance or indicating the number of technical features. Therefore, similar to features that appear separately without quantity limitations, features that are limited to "first", "second", etc. can explicitly or implicitly include one or more of the features.

[0052] In the present disclosure, unless otherwise clearly specified and defined, such terms as "mounted", "connected", "coupled", "connected", "fixed", and so on should be understoodin a broad sense. For example, it can be a fixed connection, or a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or be indirectly connected via an intermediate medium; or it can be an internal communication between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present disclosure according to specific situations.

[0053] In the present disclosure, for convenience of description, the operator (for example, a physician) is used as a reference object, and the side close to the operator is called "proximal", and the side away from the operator is called "distal".

[0054] FIG. 1 generally illustrates a reusable motorized auto-injection device according to an embodiment of the present disclosure. The reusable motorized auto-injection device includes a housing 1, a motor 2 housed in the housing 1, a drive shaft 6, a sleeve 7, and a circuit switcher. The drive shaft 6 is driven by the motor 2 to move linearly. The sleeve 7 is configured to receive a syringe 10.

[0055] In this embodiment, the housing 1 comprises a first housing portion la and a second housing portion lb, each with a top cover (not shown in the figures). As shown, the motor 2 and the drive shaft 6 may be provided in the first housing portion la and the sleeve 7 may be provided in the second housing portion lb. The first housing portion la and the second housing portion lb may be removably attached together, e.g., by means of a snap connection, a threaded connection, etc., in order to open the housing 1 and load the syringe 10 into the sleeve 7. In the embodiment shown, the housing 1 has a substantially square cross-section, but any other shape of cross-section is possible, such as rectangular, circular, oval, and so on. The housing 1 can be made of any suitable material, such as plastic.

[0056] A button type or pushing type switch (not shown) may be provided on the housing 1 for initiating or activating the auto-injection device, for automatically and sequentially carrying out two motions: needle insertion and medication infusion.

[0057] In addition to the motor 2, other components such as the drive shaft 6, the sleeve 7, and the circuit switcher can be also housed in the housing 1, thereby making it possible to form an integrated structure.

[0058] In an example, the motor 2 is a rotary motor which drives said drive shaft 6 by means of a motion conversion mechanism 4. The motion conversion mechanism 4 is configured to convert a rotary motion of the rotary motor into a linear movement of the drive shaft 6. For example, the motor 2 may be a micro DC motor integrated with a reduction mechanism, such as a Bringsmart™ micro motor with a rated voltage of 6 V and a rated speed of 30 rpm. Other types of rotary motors are also possible.

[0059] As shown in FIG. 1, the motion conversion mechanism 4 comprises an outer sleeve 41 with a female thread and an inner shaft 42 with a male thread, said female thread being configured to engage said male thread. This is the realization of the motion conversion using a nut-screw mechanism. Of course it is also possible to realize this motion conversion using other mechanisms, such as a crank-connecting rod mechanism, a rack-pinion mechanism, a crankslider mechanism, and the like.

[0060] The inner shaft 42 and the drive shaft 6 may be manufactured separately and then attached together, or they may be formed integrally.

[0061] The drive shaft 6 is further provided with a slider 5 configured to non-rotationally, linearly move the drive shaft 6. The inner shaft 42 and the drive shaft 6 may be attached together via this slider 5. In the case where the inner shaft 42 is integrally formed with the drive shaft 6, the slider 5 is provided with a hole so as to be provided over them, preferably at the intersection of the inner shaft and the drive shaft. The housing 1 is provided with a linear track 17 along which the slider 5 can move linearly. In the embodiment shown in FIG. 1, the linear track 17 is formed within both the first housing portion la and the second housing portion lb.

[0062] In another example, the motor 2 may be a linear motor that can directly drive the drive shaft 6 and omit the motion conversion mechanism, the linear track, and the slider as described above. This results in a simpler and more compact structure.

[0063] The syringe 10 may be a cartridge containing a medication. In one example, as shown in FIG. 3, the syringe 10 includes a barrel 103, a distal needle 102, and a stopper (not shown) disposed in the barrel 103. Thus, such a syringe may also be referred to as a "pen needle". The syringe is provided with a lug or protrusion 101 at an end opposite to the needle 102, which rests on a corresponding lug or protrusion 701 at the proximal end of the sleeve 7 when the syringe 10 is inserted into the sleeve 7, whereby when the stopper of syringe 10 is pushed bythe drive shaft 6, due to the faster linear movement speed of the drive shaft 6 during needle insertion, the plug of syringe 10 will transmit the thrust of the drive shaft 6 to the syringe 103 and thus push the sleeve 7, allowing the syringe 10 and the sleeve 7 together to advance. In attaching the first housing portion la and the second housing portion lb together, the stopper of the syringe 10 is configured to be abutted against by the distal end of the drive shaft 6.

[0064] It should be noted that although the term "syringe" is used herein for the sake of clarity and consistency, the term is not intended to be limiting. In some arrangements, for example, the syringe may be a pen needle or a cartridge (which may, by way of example, be arranged to receive a disposable injection needle) or other medication container. In some arrangements, the syringe / pen needle / cartridge / medication container may form an integrated piece with the injection device (or part thereof).

[0065] The circuit switcher is configured to be able to automatically operate the motor 2 successively (consecutively, sequentially) in a first mode and in a second mode as the drive shaft 6 is linearly moved; in the first mode, the motor 2 is connected to a first circuit with a higher current, so that the drive shaft 6 is linearly moved at a first, faster speed, thereby enabling rapid insertion of the needle 102 of the syringe 10 within the human skin; in the second mode, the motor 2 is connected to a second circuit with a smaller current, causing the drive shaft 6 to move linearly at a second, slower speed, thereby realizing a slow infusion of the medication inside the syringe 10. In the embodiment shown, in particular referring to Fig. 2, the circuit switcher comprises a first conductor 11 disposed in said first circuit, a second conductor 12 disposed in said second circuit, and a movable contact 13. The movable contact 13 is configured to be able to successively (consecutively, sequentially) come into electrical contact with the first conductor 11 and the second conductor 12 and to be able to successively move in a direction along their length. The first circuit and the second circuit will be described in detail later.

[0066] For fast and smooth switching between the first and second circuits, the first conductor 11 and the second conductor 12 may be configured to be in close proximity to each other in a line. Of course, the first conductor 11 and the second conductor 12 should be arranged electrically isolated, i.e. they are electrically insulated or not electrically connected. Both thefirst conductor 11 and the second conductor 12 may also be connected together, but an electrically insulating layer is provided between them in order to electrically isolate them.

[0067] In an example, the first conductor 11 and / or the second conductor 12 are in the form of a sheet of metal, which may for example be a sheet of copper, aluminum, iron, steel, or a sheet made of any other electrically conductive material.

[0068] The movable contact 13 is attached to the drive shaft 6 and is capable of moving linearly with it. In the illustrated embodiment, the movable contact 13 is attached to the slider 5. For example, the movable contact 13 may be attached to the slider 5 by means of an L- shaped arm 14. the movable contact 13 is provided at a proximal end of the L-shaped arm 14 and is oriented to face the first conductor 11 and / or the second conductor 12. The use of the L- shaped arm allows to fully utilize a space between the motion conversion mechanism 4 or the motor 2 and the inner surface of the housing 1, thereby making the whole structure more compact. Of course, other shaped arms can be used, for example a straight arm.

[0069] When activating the auto-injection device, the movable contact 13 is configured to initially come into electrical contact with the first conductor 11; as the drive shaft 6 is moved linearly distally, the movable contact is moved over the surface of the first conductor 11 in the lengthwise direction of the first conductor 11; and when it moves to the end of the first conductor 11, it is out of electrical contact with the first conductor 11, while it then quickly comes into electrical contact with the second conductor 12 and continues to move over the surface of the second conductor 12 in the lengthwise direction of the second conductor 12. In this regard, a length of the first conductor 11 or a distance traveled by the movable contact 13 over the first conductor 11 corresponds substantially to a distance that the needle 102 of the syringe 10 is rapidly moved (i.e., inserted), while a length of the second conductor 12 or a distance traveled by the movable contact 13 over the second conductor 12 corresponds substantially to a distance that the stopper of the syringe 10 is slowly moved (i.e., the medication is infused).

[0070] The specific configuration of the circuit switcher described above is merely illustrative, and other configurations of circuit switcher are possible. For example, a two-position changeover switch may be used for circuit switching.

[0071] The sleeve 7 is provided in the second housing portion lb, which is configured to be able to be moved distally under the thrust action of the drive shaft 6. A distal stop 9 is further provided in the second housing portion lb, which distal stop may be in the form of an inwardly extending protrusion or a baffle, or may be in the form shown in FIGS. 1, 2, or 4. The distal stop 9 defines the maximum position at which the sleeve 7 can move distally, preventing the needle from moving further distally during medication infusion. Accordingly, a proximal stop 15 (e.g., in the form of an inwardly extending protrusion or a baffle) is provided at the proximal end of the second housing portion lb, which proximal stop 15 defines the most proximal position (i.e., the initial position) of the sleeve 7, i.e., defines the furthest position to which the sleeve 7 moves proximally during reset.

[0072] Referring in particular to FIG. 4, a reset spring 8 is provided around the sleeve 7. One end of the reset spring 8 rests against the distal stop 9 and the other end rests against an outwardly extending lug or protrusion 701 of the sleeve 7. The reset spring 8 biases the sleeve 7 towards the proximal stop 15. When the motor 2 operates in the first mode, the drive shaft 6 rapidly moves linearly, in which case, due to the incompressibility of the liquid medication inside the syringe 10 and the medication is discharged very slowly through the needle 102, i.e. at a period of time of the rapid linear movement of the drive shaft 6 (which lasts for a very short period of time, typically no more than 1 second), the medication does not have time to be discharged at all, and the thrust of the drive shaft 6 is transmitted to the syringe, thereby moving the entire syringe 10 and consequently the sleeve 7 together against the biasing force of the reset spring 8, and thereby driving the needle 102 of the syringe 10 to be inserted quickly into a patient . After the infusion is finished, the reset spring 8 may bias the sleeve 7 proximally to reset the sleeve 7 for re-use.

[0073] The maximum distance that the sleeve 7 can be moved distally from its initial position corresponds to the insertion depth of the needle 102. Thus, adjusting this distance can adjust the insertion depth of the needle. In an example, the position of the distal stop 9 is configured to be adjustable, thereby forming a depth adjuster that is provided distal to the distal end of the sleeve 7 and spaced apart from the distal end by a distance D that determines the depth of insertion of the needle 102 of the syringe 10. This provides the user with the flexibility to adjustthe depth of insertion of the needle according to the different requirements of the medication infusion as well as the different sites of infusion.

[0074] In the embodiment shown, see FIG. 4, said depth adjuster comprises a U-shaped body 902, with a through-hole formed in the bottom wall of said U-shaped body for free passage of the syringe 10. At the proximal end of each of two sidewalls of the U-shaped body 902 is formed a tab 901 for pinching by the user's fingers, said tab 901 being configured to be able to move along a slit in the housing 1 (specifically the second housing part lb) in order to adjust said distance D.

[0075] Said depth adjuster further comprises a pawl or outer tooth 903 formed on each of the two sidewalls of the U-shaped body 902 and a plurality of inner teeth 904 disposed opposite to said pawl or outer tooth 903, said pawl or outer tooth 903 being configured to selectively engage a corresponding tooth of said plurality of inner teeth 904 so as to fix said distance D. Optionally, said plurality of inner teeth 904 are formed in the inner wall of the housing 1 (specifically the second housing part lb). During operation, the tabs 901 are pressed towards each other to cause the pawl or outer teeth 903 to disengage with the corresponding inner tooth of the plurality of inner teeth 904, thereby enabling the tabs 901 to move along the slit to adjust the distance D; when the distance D is adjusted to a desired value, the tabs 901 are released and relatively away from each other to engage the pawl or outer tooth 903 with the corresponding inner tooth of the plurality of inner teeth 904 once again, thereby fixing the U-shaped body 901 and thus fixing the distance at the desired value.

[0076] The motor 2 is powered by a power source 3, which is shared by a first circuit and a second circuit. In accordance with the present disclosure, in order to have different speeds of the drive shaft 6 during needle insertion and during medication infusion, the current supplied to the motor 2 by the first circuit when energized is less than the current supplied to the motor 2 by the second circuit when energized.

[0077] According to one embodiment of the present disclosure, the different currents described above can be realized using a dual resistor circuit scheme, as shown in FIG. 5.

[0078] As shown in FIG. 5, a first circuit starts from the motor 2 and sequentially connects in series the power source 3, the switch, the movable contact 13, and the first conductor 11, and then back to the motor 2, forming a closed circuit. A second circuit starts from the motor 2 andsequentially connects in series the power source 3, the switch, the movable contact 13, the second conductor 12, the resistor Rl, and then back to the motor 2, thus forming another closed circuit. Compared to said first circuit, said second circuit has an additional resistor Rl, whereby said second circuit produces a smaller current when energized and the motor 2 is supplied with the smaller current. This resistor Rl is connected at one end to the motor and at the other end to the second conductor 12. During the initial linear movement (i.e. during the insertion of the needle), the total resistance value of the first circuit is lower and therefore the current is higher, which results in a higher speed of the motor 2 and a faster linear movement of the drive shaft 6. When switching to the second circuit with the additional resistor Rl, the total resistance value of the second circuit is higher and therefore the current is lower, which results in a lower speed of the motor 2 and a slower speed of linear movement of the drive shaft 6. This may be referred to as a dual speed scheme using a dual resistor circuit.

[0079] Typically, the resistance value of resistor Rl can be designed to match the resistance value of motor 2. For example, if the motor 2 has a resistance value of 5 Ohms, the resistance value of the resistor Rl may also be 5 Ohms (at which point the speed may be halved), or may be some other value, such as 2.5 Ohms, 10 Ohms, and so on, determined by the speed requirements.

[0080] Optionally, the resistance value of the resistor Rl is adjustable. In this way, the user can flexibly adjust the speed of medication infusion according to different requirements of medication infusion.

[0081] In this embodiment, the power source 3 may be a battery, such as a non-rechargeable battery or a rechargeable battery, or it may be an AC / DC converter, such as a power adapter.

[0082] According to another embodiment of the present disclosure, the different currents described above can also be realized using a dual voltage circuit scheme, as shown in FIG. 6.

[0083] As shown in FIG. 6, a first circuit starts from the motor 2 and sequentially connects in series the power source 3 (i.e., the first power source), the switch, the movable contact 13, the first conductor 11, and the second power source, and then back to the motor 2, forming a closed circuit. A second circuit starts from the motor 2 and sequentially connects in series the power source 3 (i.e. the first power source), the switch, the movable contact 13, and the second conductor 12, and then back to the motor 2, thus forming another closed circuit. In contrast tosaid second circuit, said first circuit additionally adds a second power source, the first power source and the second power source being connected in series, whereby both said first power source and said second power source together supply power to the motor 2 when the motor 2 is connected to said first circuit; whereas power is supplied to the motor 2 only by said first power source when the motor is connected to said second circuit. That is, the circuit switcher is utilized to switch a circuit with two power supplies in series to another circuit with a single power source. During the initial linear movement (i.e. during needle insertion), the circuit has two power supplies in series, which results in a higher current and thus a higher speed of the motor 2 and a faster linear movement of the drive shaft 6. When switching to a single power source circuit without the second power source, the current is lower and the linear movement slows down. This can be referred to as a dual speed scheme with a dual voltage circuit.

[0084] In this embodiment, the power source 3 (i.e. the first power source) and the second power source each may be a battery, such as a non-rechargeable battery or a rechargeable battery, or they each may be an AC to DC converter, such as a power adapter.

[0085] In this embodiment, the second circuit may further be provided with a short-circuit proof resistor R2. The short-circuit proof resistor R2 is connected to the second conductor 12 at one end thereof and to the motor 2 at the other end thereof. In this way, it is possible to prevent transient short-circuiting of the second power source which may occur when the movable contact 13 moves to the junction between the first conductor 11 and the second conductor 12 due to the possibility of it contacting both the first conductor 11 and the second conductor 12 at the same time. The main purpose of the short-circuit proof resistor R2 herein is to prevent transient short-circuiting, and therefore a resistor with a small resistance value can be selected. Typically, the resistance value of the short-circuit proof resistor R2 ranges from 1 to 10 Ohms.

[0086] Optionally, the resistance value of said short-circuit proof resistor is adjustable. This allows the user to flexibly adjust the medication infusion rate according to different requirements of the medication infusion.

[0087] In use, the user opens the housing 1 by detaching the second housing part lb from the first housing part la, and then loads the syringe 10 into the sleeve 7 so that the protrusion 101 of the syringe 10 rests on the corresponding protrusion 701 of the sleeve 7, and then attachesthe first housing portion la and the second housing portion lb. Next, the user aligns the distal end of the entire injection device at the injection site and triggers the switch. The motor 2 is first connected to a first circuit with a higher current and therefore drives said drive shaft 6 at a faster speed in a rapid linear movement. Under the thrust action of the drive shaft 6, the syringe 10 and the sleeve 7 instantaneously move together, thereby inserting the needle into the injection site. When the distal end of the sleeve 7 contacts the distal stop 9 or the bottom wall of the U-shaped body of the depth regulator, it is no longer moved further distally, thus completing the rapid insertion of the needle. Immediately thereafter, the motor 2 is connected to a second circuit with a lower current via the circuit switcher and thus drives said drive shaft 6 at a slower speed in a slow linear movement. At this point, the sleeve 7 is prevented from further moving distally and the proximal protrusion 101 of the syringe 10 rests against the proximal protrusion 701 of the sleeve 7, so that the barrel 103 of the syringe 10 cannot move further distally either; at this point, the stopper of the syringe 10 can be further moved distally by the thrust action of the drive shaft 6, so that the medication is slowly infused into the patient. When the infusion is finished, the drive shaft 6 can be restored to the initial position by reversing the motor 2, while the sleeve 7 is also restored to the initial position under the biasing action of the reset spring 8.

[0088] The main advantage of the reusable motorized auto-injection device of the present disclosure over the prior art is that there is only one set of mechanical drive mechanism, i.e., the drive shaft and the motor circuit. Having only one set of drive mechanism improves the reliability and compactness of the auto-injection device and reduces the cost.

[0089] The reusable motorized auto-injection device of the present disclosure may be applicable to many auto-injection devices, such as Epipen, BD Physioect™ disposable autoinjector, Aria smart autoinjector, and so on.

[0090] The present disclosure may include any feature or combination of features or a generalization thereof implicitly or explicitly disclosed herein, without limiting the scope of any of the limitations enumerated above. Any of the relevant components, features and / or structural arrangements described herein may be combined in any suitable manner.

[0091] The particular embodiments disclosed above are merely exemplary, and it will be apparent to those skilled in the art who benefit from the teachings herein that the presentdisclosure may be modified and implemented in different but equivalent ways. For example, the method steps described above may be performed in a different order. Furthermore, there is no limitation on the details of the constructions or designs illustrated herein, except as set forth in the following claims. It is therefore apparent that changes and modifications may be made to specific embodiments of the above disclosure, and all such variations are considered to fall within the scope and spirit of the present disclosure. Accordingly, the protection sought herein is set forth in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A reusable motorized auto-injection device comprising: a housing; a single motor, said motor being housed within said housing; a drive shaft, said drive shaft configured to move linearly driven by said motor; a sleeve, said sleeve configured to receive a syringe containing a medication; and a circuit switcher, wherein said drive shaft is configured to be able to engage a stopper of said syringe so as to push said stopper, and wherein said circuit switcher is configured to be able to automatically cause said motor to operate in a first mode and in a second mode successively with the linear movement of said drive shaft, wherein in said first mode, said motor is connected to a first circuit such that said drive shaft is linearly moved at a first, faster speed, thereby realizing rapid insertion of a needle of said syringe, and wherein in said second mode, said motor is connected to a second circuit such that said drive shaft to move linearly at a second, slower speed, thereby realizing a slow infusion of medication from said syringe.

2. A reusable motorized auto-injection device according to claim 1, characterized in that said circuit switcher comprises a first conductor disposed in said first circuit, a second conductor disposed in said second circuit, and movable contacts, said movable contacts configured to be capable of moving successively over said first conductor and over said second conductor in electrical contact.

3. A reusable motorized auto-injection device according to claim 2, characterized in that said first conductor and said second conductor are arranged in close proximity to each other in a line, but electrically isolated from each other.5XF0207.DOCX 194. A reusable motorized auto-injection device according to claim 2, characterized in that said first conductor and / or said second conductor are in the form of a sheet of metal.

5. A reusable motorized auto-injection device according to claim 2, characterized in that said movable contact is attached to said drive shaft, capable of moving linearly with said drive shaft, and said movable contact is configured to initially come into electrical contact with said first conductor, whereby said motor is connected to said first circuit and thereby operates in said first mode; as said drive shaft moves linearly, said movable contact is disengaged from electrical contact with said first conductor and is then brought into electrical contact with said second conductor, such that said motor is switched to be connected to said second circuit, thereby operating in said second mode.

6. A reusable motorized auto-injection device according to claim 1, characterized in that the current supplied to said motor by said first circuit when energized is less than the current supplied to said motor by said second circuit when energized.

7. A reusable motorized auto-injection device according to claim 6, characterized in that said motor is powered by a power source which is shared by said first circuit and said second circuit.

8. A reusable motorized auto-injection device according to claim 6, characterized in that an additional resistor is added to said second circuit compared to said first circuit, thereby enabling said motor to be supplied with a smaller current.

9. A reusable motorized auto-injection device according to claim 7, characterized in that said power source is a first power source, said first circuit additionally has a second power source as compared to said second circuit, said first power source and said second power source are connected in series, whereby both said first power source and said5XF0207.DOCX 20second power source together supply power to said motor when said motor is connected to said first circuit; and power is supplied to said motor only by said first power source when said motor is connected to said second circuit.

10. A reusable motorized auto-injection device according to claim 9, characterized in that said second circuit is further provided with an short-circuit proof resistor disposed between said second conductor and said motor.

11. A reusable motorized auto-injection device according to claim 1, characterized in that a proximal stop is provided with on the inner wall of said housing, which proximal stop defines a most proximal position of said sleeve.

12. A reusable motorized auto-injection device according to claim 1, characterized in that said reusable motorized auto-injection device further comprises a distal stop provided distal to a distal end of said sleeve and spaced apart from said distal end by a distance, said distance determining a depth of insertion of a needle of said syringe.

13. A reusable motorized auto-injection device according to claim 12, characterized in that said reusable motorized auto-injection device further comprises a reset spring surrounding said sleeve, one end of said reset spring resting against said distal stop and the other end resting against an outwardly extending proximal protrusion of said sleeve.

14. A reusable motorized auto-injection device according to claim 12, characterized in that said distal stop comprises a U-shaped body with a bottom wall being formed with a through hole for free passage of said syringe.

15. A reusable motorized auto-injection device according to claim 12, characterized in that said distal stop comprises a U-shaped body with a tab for a user's finger5XF0207.DOCX 21to pinch formed at a distal end of each of said two sidewalls of said U-shaped body, said tab configured to be capable of being moved along a slit in said housing so as to adjust said distance16. A reusable motorized auto-injection device according to claim 14, characterized in that said distal stop further comprises a pawl or outer tooth formed in each of said two sidewalls of said U-shaped body and a plurality of inner teeth disposed opposite to said pawl or outer tooth, said pawl or outer tooth configured to selectively engage a corresponding one of said plurality of inner teeth so as to fix said distance.

17. A reusable motorized auto-injection device according to claim 16, characterized in that said plurality of inner teeth are formed on an inner wall of said housing.

18. A reusable motorized auto-injection device according to claim 1, characterized in that said drive shaft is provided with a slider, said slider being configured to non-rotationally, linearly move said drive shaft.

19. A reusable motorized auto-injection device according to claim 18, characterized in that said slider is configured to move along a linear track, said linear track being provided within said housing.

20. A reusable motorized auto-injection device according to claim 18, characterized in that said circuit switcher comprises a first conductor disposed in said first circuit, a second conductor disposed in said second circuit, and a movable contact, said movable contact configured to be capable of making electrical contact with said first conductor and with said second conductor one after the other, said movable contact being attached to said slider.5XF0207.DOCX 2221. A reusable motorized auto-injection device according to claim 20, characterized in that said movable contact is attached to said slider by means of an L-shaped arm.5XF0207.DOCX 23

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