Drive mechanism and drug delivery device

Abstract

The driving mechanism provided by the present application is applied to a medicine delivery device, and comprises a push rod, a driving rod, a driving ratchet, a residual amount control ring, a locking ratchet disc and a power spring. The push rod is arranged in the driving rod, and the outer wall of the push rod is provided with two sections of external threads separated by a groove. The driving ratchet is sleeved on the push rod, and the inner wall of the driving ratchet is provided with a sliding block matched with the groove of the push rod. The residual amount control ring is arranged in the driving rod, and the internal thread of the inner wall of the residual amount control ring is engaged with the external thread of the push rod. The power spring is sleeved outside the driving rod. Accordingly, the contact area can be increased, and the transmission efficiency and operation stability can be improved through the design of the two external threads.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a drive mechanism and a drug delivery device. Background Technology

[0002] Chinese Patent Publication No. CN220110205U discloses a drug delivery device, including a pen cap, a drug delivery mechanism, and a dosage adjustment mechanism. The right side of the pen cap is connected to the drug delivery mechanism, which includes a connecting part consisting of a drug delivery section and a pen barrel. The right side of the pen barrel is connected to the dosage adjustment mechanism. The dosage adjustment mechanism includes a dosage adjustment section and an observation section. A knob is provided in the dosage adjustment section. The knob is connected to the pen barrel and cooperates with a scale sleeve to adjust the drug delivery amount.

[0003] Furthermore, in existing technologies, drug delivery devices typically use a push rod located within the drug delivery mechanism to release pre-filled medication from a reservoir. In particular, the push rod often employs a continuous and single external thread structure, achieving actuation such as driving and linkage through threaded engagement with other drive components (such as knobs, sleeves, etc.).

[0004] However, there are still some technical problems in its practical application, such as asymmetrical torque transmission and uneven load distribution, which may cause the push rod to become eccentric or vibrate during the driving process, thus affecting the transmission stability and output accuracy.

[0005] Therefore, the existing push rod structure does indeed need urgent improvement. Utility Model Content

[0006] To overcome the shortcomings of existing technologies, the main purpose of this invention is to provide a drive mechanism and a drug delivery device. By designing the external thread structure of the push rod in the drive mechanism, the problems existing in the push rod transmission structure of the drug delivery device in the prior art are improved. It has the characteristics of large contact area, uniform load distribution, high transmission efficiency and good stability, which can effectively improve the reliability and accuracy of the overall transmission process when it meshes with the margin control ring or engages with the drive ratchet.

[0007] To achieve the above objectives, the drive mechanism provided in this invention, applied to a drug delivery device, includes:

[0008] The push rod has two external threads arranged separately on its outer surface. The two external threads extend along the axial direction of the push rod, and are separated by two grooves extending along the rod axis of the push rod, so that the two external threads are located at two opposite positions in the circumferential direction of the push rod.

[0009] The drive rod is a hollow tubular structure, and a push rod is installed inside the drive rod;

[0010] A drive ratchet is fitted onto a push rod. The inner wall of the drive ratchet has two sliders, which are respectively inserted into two grooves on the push rod, so that the drive ratchet and the push rod are engaged.

[0011] The margin control ring is located inside the drive rod, and the inner wall of the margin control ring is provided with an internal thread that meshes with the two external threads of the push rod, and is screwed onto the push rod.

[0012] The locking ratchet disc, a sleeve-type structure, is fitted onto the drive rod; and

[0013] A power spring is sleeved on the drive rod, with each end of the power spring hooked against the drive rod and the locking ratchet, so that the elastic force of the power spring can drive the drive rod to move.

[0014] In one embodiment, the pitch of the two external threads is the same.

[0015] In one embodiment, a graduated sleeve is also fitted onto the drive rod, and the graduated sleeve is driven by the push rod to move relative to the drive rod.

[0016] Accordingly, the push rod outer surface of the drive mechanism provided in this invention is provided with two discontinuous external threads, which have a large contact area and uniform load distribution, thus helping to improve transmission efficiency and operational stability.

[0017] In addition, this invention also provides a drug delivery device, including a pen barrel and a drive mechanism disposed within the pen barrel.

[0018] In one embodiment, the drug delivery device further includes:

[0019] Ratchet sleeve, located at the front end of the pen barrel; and

[0020] The graduated sleeve is fitted over the outside of the drive rod and located inside the pen barrel.

[0021] In one embodiment, the scale sleeve is a tubular structure with an upper limit end and a lower limit end at its two ends, the pen barrel has an upper limit protrusion, the upper limit protrusion is located inside the pen barrel at the position corresponding to the upper limit end of the scale sleeve, and the ratchet sleeve has a lower limit protrusion, which is located on the ratchet sleeve relative to the lower limit end of the scale sleeve.

[0022] Accordingly, when the scale sleeve moves upward relative to the pen barrel, the lower limit protrusion and the upper limit end abut against or interfere with each other to limit further upward movement of the scale sleeve relative to the pen barrel. Conversely, when the scale sleeve moves downward relative to the pen barrel, the lower limit protrusion and the lower limit end abut against or interfere with each other to limit further downward movement of the scale sleeve relative to the pen barrel. As the limit for the maximum dosage, this determines the effective range of movement of the scale sleeve relative to the pen barrel.

[0023] In one embodiment, the drug delivery device further includes:

[0024] The pen cap fits onto the pen barrel;

[0025] The knob is located at the rear end of the pen barrel and is connected to the pen barrel;

[0026] A button, located at the rear of the pen barrel, extends partially through the knob and is situated inside the actuator rod; and

[0027] A return spring is located between the button and the knob.

[0028] In one embodiment, the drug delivery device further includes a drug cartridge located at the front end of the ratchet sleeve.

[0029] In one embodiment, the drug delivery device further includes an adjusting spring arm disposed inside the locking ratchet disc, the free end of which can contact the toothed surface of the locking ratchet disc.

[0030] Therefore, this work has at least the following characteristics:

[0031] 1. Double-threaded push rod structure

[0032] The outer surface of the push rod has two discontinuous external threads, which provide a large contact area and uniform load distribution, thus helping to improve transmission efficiency and operational stability.

[0033] 2. Warning sound effects, stop rotation, or irreversible rotation.

[0034] The design of the drive ratchet and adjusting spring arm enables a tapping sound to indicate the dosage or the injection process. Furthermore, the drive ratchet employs a one-way limiting structure, which, through the cooperation between the adjusting spring arm and the locking ratchet disc, solves the problem of knob slippage and reverse rotation, and also serves as an anti-rotation mechanism.

[0035] 3. Limiting structure

[0036] The upper and lower limit ends of the scale sleeve correspond to the upper limit protrusion of the pen barrel and the lower limit protrusion of the ratchet sleeve, respectively, which can achieve the foolproof design of the starting position and ensure the stability of the total stroke at the beginning and end.

[0037] 4. Dynamic spring

[0038] Because the number of power spring contact components is reduced in the overall structural design, the deformation amplitude during the power storage process is reduced, which also improves the smoothness and reliability of the overall injection action.

[0039] 5. Margin control

[0040] The remaining dosage is controlled by a margin control loop, and the design of increasing, decreasing and reciprocating margin control saves space.

[0041] The specific techniques used in this work will be further explained through the following embodiments and accompanying drawings. Attached Figure Description

[0042] Figure 1 This is a three-dimensional assembly diagram of a preferred embodiment of the invention.

[0043] Figure 2 This is a three-dimensional exploded view of a preferred embodiment of the invention.

[0044] Figure 3 for Figure 1 Sectional view along section line 3-3.

[0045] Figure 4 This is a three-dimensional schematic diagram of the push rod.

[0046] Figure 5 This is a side view of the push rod.

[0047] Figure 6 This is a three-dimensional schematic diagram of a graduated sleeve.

[0048] Figure 7 This is a three-dimensional schematic diagram of the ratchet sleeve.

[0049] Figure 8 To continue Figure 3 A schematic diagram of its operation.

[0050] Figure 9 To continue Figure 8 A schematic diagram of its operation.

[0051] Figure 10 This is a three-dimensional schematic diagram of the ratchet drive.

[0052] Figure 11 This is a schematic diagram showing the assembled state of the push rod and the drive ratchet.

[0053] In the diagram: A: Drug delivery device; 10: Pen cap; 11: Pen barrel; 111: Upper limit protrusion; 20: Drive mechanism; 21: Push rod; 211: External thread; 212: Groove; 213: Push rod washer; 22: Drive rod; 23: Drive ratchet; 231: Slider; 24: Power spring; 25: Locking ratchet disc; 30: Knob; 31: Button; 32: Return spring; 40: Medicine box; 60: Adjustment arm; 70: Ratchet sleeve; 71: Lower limit protrusion; 80: Scale sleeve; 81: Upper limit end; 82: Lower limit end; 90: Balance control ring; 91: Internal thread. Detailed Implementation

[0054] The technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0055] In this document, the number of components and parts described is not limited. This is merely for illustrative purposes and to provide a general understanding of the scope of this work. Furthermore, the terms "a" or "an" may be used to describe components and parts of this document, and such descriptions should be understood to include one or at least one, with the singular also including multiples.

[0056] In this document, the terms "comprising," "having," or any other similar terms are intended to cover non-exclusive inclusions. For example, a component or structure containing multiple elements is not limited to those listed herein, but may include other elements not expressly listed but which are generally inherent to the component or structure.

[0057] First, see Figures 1 to 5 This embodiment provides a drive mechanism 20, applied to a drug delivery device A, wherein the drive mechanism 20 includes:

[0058] The push rod 21 has two external threads 211 arranged separately on its outer surface. The two external threads 211 extend along the axial direction of the push rod 21, and are separated by two grooves 212 extending along the rod axis of the push rod 21, so that the two external threads 211 are located at two opposite positions in the circumferential direction of the push rod 21. Figure 5 and Figure 6 As shown;

[0059] The drive rod 22 is a hollow tubular structure, and a push rod 21 is provided inside the drive rod 22;

[0060] A drive ratchet 23 is sleeved on a push rod 21. The inner wall of the drive ratchet 23 has two sliders 231, such as... Figure 10 As shown, the sliders 231 are respectively inserted into the two grooves 212 on the push rod 21, so that the drive ratchet 23 engages with the push rod 21, as shown. Figure 11 As shown;

[0061] The margin control ring 90 is located inside the drive rod 22, and the inner wall of the margin control ring 90 is provided with an internal thread 91 that meshes with the two external threads 211 of the push rod 21. It is screwed onto the push rod 21. Figure 3 As shown;

[0062] The locking ratchet disc 25 is a sleeve-type structure, sleeved on the drive rod 22; and

[0063] A power spring 24 is sleeved on the drive rod 22, and both ends of the power spring 24 are hooked onto the drive rod 22 and the locking ratchet 25, so as to use the elastic force of the power spring 24 to drive the drive rod 22 to move.

[0064] Accordingly, due to the structural design of the two external threads 211 of the push rod 21, which have the characteristics of large contact area, uniform load distribution, high transmission efficiency and good stability, it can effectively improve the reliability and accuracy of the overall transmission process when it meshes with the margin control ring 90 or engages with the drive ratchet 23.

[0065] Furthermore, the detailed structural design of this creation is described below.

[0066] like Figures 1 to 2 As shown, the drug delivery device A includes a pen cap 10, a pen barrel 11, a drive mechanism 20, a knob 30, a button 31, a return spring 32, a medicine box 40, an adjustment spring arm 60, a ratchet sleeve 70, and a scale sleeve 80.

[0067] The push rod 21 is made of polybutylene terephthalate (PBT) with 30% glass fiber to increase rigidity and prevent bending under stress during injection, which could affect the actual dosage. Furthermore, the pitch of the two external threads 211 is designed to be the same.

[0068] like Figure 3 As shown, the power spring 24 is set in the U-shaped space in the drive rod 22, so that the power spring 24 will not come into contact with other components, thereby reducing its deformation.

[0069] The medicine box 40 is located at the front end of the ratchet sleeve 70 and is used to store medicine packaging materials.

[0070] The pen cap 10 is used to cover the pen barrel 11 when not in use and to cover the medicine box 40, thereby achieving a sealed protection and preventing external contamination.

[0071] The pen barrel 11 has a hollow cylindrical structure, and a drive mechanism 20 is installed inside it.

[0072] The knob 30 is located at the rear end of the pen 11 and is connected to the pen 11. The user can adjust the dosage by rotating the knob 30.

[0073] Button 31 is located at the rear end of pen barrel 11 and extends to the left through knob 30, so that it is partially located inside drive rod 22. When button 31 is pressed, force can be effectively transmitted to drive rod 22 to start the injection action.

[0074] The reset spring 32 is located between the button 31 and the knob 30 to provide reset force after injection.

[0075] The locking ratchet disc 25 is a sleeve-type structure, fitted onto the drive rod 22. The locking ratchet disc 25 and the adjusting spring arm 60 constitute the main limiting and positioning structure of the adjusting module, used to control the rotational movement during dosage adjustment.

[0076] The adjusting spring arm 60 is installed inside the locking ratchet disc 25, and its free end can contact the toothed surface of the locking ratchet disc 25. When the knob 30 is turned to adjust the dosage, it is driven by the drive rod 22, causing the end of the adjusting spring arm 60 to periodically tap against the teeth of the locking ratchet disc 25, thereby producing a continuous adjustment sound to indicate to the user the progress of the current dosage setting.

[0077] In addition, the adjusting spring arm 60 and the locking ratchet disc 25 form a limit stop to prevent the knob 30 from slipping.

[0078] The ratchet sleeve 70 is located at the front end of the pen barrel 11, and the ratchet sleeve 70 cooperates with the drive ratchet 23 to realize the limiting function of the linear movement of the push rod 21.

[0079] like Figure 3 As shown, the graduated sleeve 80 is fitted over the drive rod 22, and is made of polybutylene terephthalate (PBT) to reduce friction. The sleeve rotates synchronously with the drive rod 22 and produces axial movement to display the output dose. It can be rotated in reverse and reset during injection.

[0080] The graduated sleeve 80 is fitted outside the drive rod 22 and located inside the pen barrel 11, used to display the dosage status during dosage adjustment and injection. When the user rotates the knob 30 to adjust the dosage, the push rod 21 is driven to rotate, and through the transmission relationship between the graduated sleeve 80 and the drive rod 22, the graduated sleeve 80 can move axially, and the corresponding dosage adjustment value can be read through the scale window or external markings.

[0081] Furthermore, the scale sleeve 80 is made of polypropylene terephthalate (PTT) and lubricant, which not only maintains rigidity but also allows the scale sleeve 80 to rotate smoothly, thereby reducing friction between it and the drive components, improving the smoothness of adjustment and service life.

[0082] In addition, the drug delivery device A also includes a limiting structure designed to restrict the range of movement of the scale sleeve 80 within the pen barrel 11. Specifically, as Figure 6 As shown, the graduated sleeve 80 is a tubular structure with an upper limit end 81 and a lower limit end 82 at its two ends. The upper limit end 81 is the initial positioning point, and the scale is 0.

[0083] like Figure 2 As shown, the pen barrel 11 has an upper limit protrusion 111, which is located inside the pen barrel 11 at the position corresponding to the upper limit end 81 of the scale sleeve 80. Figure 7 As shown, the ratchet sleeve 70 has a lower limit protrusion 71, and the lower limit end 82 relative to the corresponding scale sleeve 80 is provided on the ratchet sleeve 70.

[0084] Accordingly, when the scale sleeve 80 moves upward relative to the pen barrel 11, the lower limit protrusion 111 and the upper limit end 81 abut against or interfere with each other to limit the scale sleeve 80 from moving further upward relative to the pen barrel 11; conversely, when the scale sleeve 80 moves downward relative to the pen barrel 11, the lower limit protrusion 71 and the lower limit end 82 abut against or interfere with each other to limit the scale sleeve 80 from moving further downward relative to the pen barrel 11, thus serving as a limit for the maximum dose.

[0085] Accordingly, the effective range of movement of the scale sleeve 80 relative to the pen barrel 11 is determined, and the foolproof design to reach the starting position ensures the stability of the total stroke at the beginning and end.

[0086] The following provides a more detailed explanation of how this work can be used:

[0087] like Figure 3 As shown, each component is in its initial state.

[0088] like Figure 8 As shown, the process of adjusting the injection dosage is as follows: First, turn the knob 30 clockwise to rotate the drive rod 22. The drive rod 22 then rotates the scale sleeve 80 clockwise and moves it to the left. During this process, the power spring 24 is activated and stores power, simultaneously rotating the residual control ring 90 clockwise and moving it to the right. Alternatively, turning the knob 30 counterclockwise allows for the opposite operation.

[0089] like Figure 9 As shown, the injection process begins by pressing button 31 to compress the reset spring 32, simultaneously forcing the drive rod 22 to disengage from the adjusting spring arm 60 and engage with the drive ratchet 23. Since the power spring 24 was previously in a charged state, it drives the drive rod 22 to rotate counterclockwise. The drive rod 22 then drives the scale sleeve 80 to rotate counterclockwise and move to the right until it returns to its original position. Simultaneously, the drive rod 22 also drives the drive ratchet 23, which in turn moves the push rod 21 axially. This allows the push rod washer 213 at the front end of the push rod 21 to compress the medication in the medicine cartridge 40, thus administering the medication. At this time, the remaining amount control ring 90 moves to the left within the drive rod 22 as the push rod 21 moves.

[0090] Finally, release button 31, and the reset spring 32 will push button 31 and drive rod 22 back to their original position, as shown in Figure 3.

[0091] Therefore, this work has at least the following characteristics:

[0092] 1. Double-threaded push rod structure

[0093] The outer surface of the push rod has two discontinuous external threads, which provides a large contact area and uniform load distribution, thus helping to improve transmission efficiency and operational stability.

[0094] 2. Warning sound effects, stop rotation, or irreversible rotation.

[0095] The design of the drive ratchet and adjusting spring arm enables a tapping sound to indicate the dosage or the injection process. Furthermore, the drive ratchet employs a one-way limiting structure, which, through the cooperation between the adjusting spring arm and the locking ratchet disc, solves the problem of knob slippage and reverse rotation, and also serves as an anti-rotation mechanism.

[0096] 3. Limiting structure

[0097] The upper and lower limit ends of the scale sleeve correspond to the upper limit protrusion of the pen barrel and the lower limit protrusion of the ratchet sleeve, respectively, which can achieve the foolproof design of the starting position and ensure the stability of the total stroke at the beginning and end.

[0098] 4. Dynamic spring

[0099] Because the number of power spring contact components is reduced in the overall structural design, the deformation amplitude during the power storage process is reduced, which also improves the smoothness and reliability of the overall injection action.

[0100] 5. Margin control

[0101] The remaining dosage is controlled by a margin control loop, and the design of increasing, decreasing and reciprocating margin control saves space.

[0102] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A drive mechanism applied to a drug delivery device, characterized in that, The driving mechanism comprises: a push rod, an outer surface of which is provided with two external threads arranged separately from each other, the two external threads extending along an axial direction of the push rod, wherein the two external threads are separated by two grooves extending along a rod axial direction of the push rod, and the two external threads are located at two opposite positions in a circumferential direction of the push rod, respectively; a driving rod, which is a hollow tubular structure, and an inside of the driving rod is provided with the push rod; a driving ratchet, which is sleeved on the push rod, and an inner wall of the driving ratchet is provided with two sliders, the two sliders are respectively inserted into the two grooves on the push rod, and the driving ratchet is clamped with the push rod; a surplus control ring, which is located inside the driving rod, and an inner wall of the surplus control ring is provided with internal threads engaged with the two external threads of the push rod, and the surplus control ring is screwed on the push rod; a locking ratchet disc, which is a sleeve structure, and the locking ratchet disc is sleeved on the driving rod; and a power spring, which is provided on the driving rod, and two ends of the power spring are respectively hooked on the driving rod and the locking ratchet disc, so that the driving rod is driven by the elastic force of the power spring.

2. The drive mechanism of claim 1, wherein, The two external threads have the same pitch.

3. A drug delivery device characterized by, The drug delivery device comprises: a pen barrel; and the driving mechanism according to any one of claims 1 to 2, which is arranged in the pen barrel.

4. The drug delivery device of claim 3, wherein The drug delivery device further comprises: a ratchet sleeve, which is located at a front end of the pen barrel; and a scale sleeve, which is sleeved outside the driving rod and is located in the pen barrel.

5. The drug delivery device of claim 4, wherein the dose dial sleeve is configured to rotate relative to the dose dial sleeve driver when the dose dial sleeve driver is rotated relative to the dose dial sleeve. The scale sleeve is a tubular structure, and has an upper limit end portion and a lower limit end portion at two ends thereof, respectively. The pen barrel has an upper limit protrusion, which is arranged in the pen barrel at a position corresponding to the upper limit end portion of the scale sleeve. The ratchet sleeve has a lower limit protrusion, which is arranged on the ratchet sleeve at a position corresponding to the lower limit end portion of the scale sleeve.

6. The drug delivery device of claim 3, wherein the needle cover is configured to be moved from the first position to the second position by the needle cover being pushed by the needle guard. The drug delivery device further comprises: a pen cap, which covers the pen barrel; a knob, which is arranged at a rear end of the pen barrel and is connected with the pen barrel; a button, which is arranged at the rear end of the pen barrel, a part of the button extends through the knob and is located inside the driving rod; and a return spring, which is arranged between the button and the knob.

7. The drug delivery device of claim 4, wherein the needle cover is configured to be moved from the first position to the second position by the needle cover being pushed by the needle guard. The drug delivery device further comprises a cartridge, which is arranged at a front end of the ratchet sleeve.

8. The drug delivery device of claim 3, wherein the needle cover is configured to be moved from the first position to the second position by the needle cover being pushed by the needle guard. The drug delivery device further comprises an adjusting elastic arm, which is arranged inside the locking ratchet disc, and a free end of the adjusting elastic arm can be in contact with a tooth surface of the locking ratchet disc.

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