Dual chamber adjustable dose pen injector

Abstract

The present application relates to pen injector technical field, specifically for double cavity adjustable dose pen injector, including intermediate connecting pipe, when one medicine placement shell needs to be injected, one pressing plate is pressed, when the pressing plate falls, one pressing rod, one pressing rod and one piston plate will be driven to fall synchronously, the piston plate will slide down in the medicine placement shell that needs to be injected, and the medicine in the medicine placement shell will be squeezed out and injected into the patient's body, when one pressing rod falls, the blocking block will move to the other end, and the moving blocking block will finally be located below the other pressing rod, at this time, the other pressing rod can be prevented from falling by the blocking block, so that the other piston plate can prevent the liquid in the other medicine placement shell from being squeezed out, so that the patient can prevent the two medicines in the medicine placement shell from being injected at the same time, and the safety and stability of injection are improved.

Description

Technical Field

[0001] This invention relates to the field of pen injector technology, specifically a dual-chamber adjustable-dose pen injector. Background Technology

[0002] A pen injector is a self-administered injection device that pre-fills a cartridge with medication inside the pen body. It typically integrates a dose adjustment knob, an injection push button, and a disposable needle. Users can set the desired dose by rotating the knob and press the push button to complete the subcutaneous injection. It is commonly used in the treatment of chronic diseases that require long-term self-administration, such as insulin, growth hormone, and GLP-1 receptor agonists.

[0003] For dual-chamber pen injectors that require separate storage of two medications and dispensing them as needed, most existing designs are equipped with two independent levers to drive the pistons of their respective chambers. This type of structure poses a significant risk of accidental activation in actual use: due to the lack of a reliable interlocking mechanism between the two levers, patients are highly likely to press both levers simultaneously due to unstable grip or operational negligence, resulting in the two medications being dispensed accidentally at the same time. This not only wastes precious medication and causes dosage errors, but may also lead to unforeseen medication safety incidents due to the inappropriate mixing of medications. Furthermore, even if the operator accidentally touches both levers one after the other, the existing structure cannot provide clear physical error-proofing feedback to indicate whether the current operation is compliant, making it difficult to fundamentally eliminate the problem of disordered drug administration caused by accidental activation. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-chamber adjustable dosage pen injector to solve the problems mentioned in the background art. Existing dual-chamber pen injectors lack an interlocking mechanism between the two push rods, which can easily lead to accidental simultaneous dispensing of medication, resulting in waste, dosage errors, and safety risks. Furthermore, they cannot provide error-proof feedback.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A dual-lumen adjustable-dose pen syringe includes a central connecting tube. An upper tube and a lower tube are fixedly connected to the upper and lower ends of the central connecting tube, respectively. Two sets of pressing injection mechanisms are installed inside the central connecting tube. Each pressing injection mechanism consists of a moving groove, a pressing rod, a pressing plate, a lower pressing rod, a drug placement shell, and a piston plate. The moving groove is formed on the circumferential surface of the upper tube. The pressing rod is slidably connected inside the upper tube, and its lower end movably penetrates the upper inner wall of the central connecting tube. The pressing plate is fixedly connected to the circumferential surface of the pressing rod. The lower pressing rod is integrally formed at its lower end. The drug placement shell is fixedly connected inside the lower tube, and its lower end movably penetrates the upper inner wall of the drug placement shell. The piston plate is fixedly connected to the lower end of the lower pressing rod. Two horizontal rods are fixedly connected between the two inner walls of the central connecting tube. Horizontal blocks are slidably connected to the circumferential surfaces of the two horizontal rods, and blocking blocks are fixedly connected to the adjacent ends of the two horizontal blocks.

[0006] Furthermore, the lower end of the drug placement shell is provided with a connection hole, the lower end of the lower tube is integrally formed with a connecting sleeve, the connecting sleeve is provided with a docking groove, a connector is detachably connected in the docking groove, the lower end of the connector is integrally formed with a puncture needle, and the upper end of the connector is provided with a transmission groove.

[0007] Furthermore, an annular groove is formed on the inner circumferential wall of the mating groove, and two sets of fixing mechanisms are provided on the outer side of the mating joint. Each set of fixing mechanisms consists of an installation groove, a snap-fit ​​spring, a snap-fit ​​groove, and a snap-fit ​​block. The installation groove and the snap-fit ​​groove are respectively formed on the circumferential surface of the mating joint and the inner circumferential wall of the mating groove. The snap-fit ​​spring is fixedly connected to one side of the inner wall of the installation groove, and the snap-fit ​​block is fixedly connected to one end of the snap-fit ​​spring, and the snap-fit ​​block is movably snapped into the snap-fit ​​groove.

[0008] Furthermore, two sets of disassembly mechanisms are provided on the outer side of the connecting sleeve. Each set of disassembly mechanisms consists of a placement groove, a movable tube, a movable block, a movable rod, a force-bearing block, a force-bearing rod, and a disassembly block. The placement groove is opened on one inner wall of the snap-fit ​​groove. The movable tube is fixedly connected to the inner circumference of the placement groove. The force-bearing block and the movable block are slidably connected inside the movable tube. The force-bearing rod is fixedly connected to one end of the force-bearing block. The disassembly block is fixedly connected to one end of the force-bearing rod. The movable rod is fixedly connected to the lower end of the movable block.

[0009] Furthermore, a trigger block is fixedly connected to the lower end of the movable rod, and a return spring is sleeved on the circumferential surface of the movable rod.

[0010] Furthermore, a telescopic rod is fixedly connected to one inner wall of the mounting groove, and the snap-fit ​​spring is sleeved on the circumferential surface of the telescopic rod.

[0011] Furthermore, the intermediate connecting tube has two dose adjustment knobs on its circumferential surface, and one end of the lower tube has an observation groove.

[0012] Furthermore, an alignment plate is fixedly connected to the circumferential surface of the lower tube, and one end of the alignment plate is provided with multiple scale grooves.

[0013] Furthermore, the blocking block is trapezoidal and is divided into a first inclined area, an abutment area, and a second inclined area from left to right according to its shape.

[0014] Furthermore, one end of the snap-fit ​​block is bead-shaped.

[0015] The technical solution provided by this invention has the following advantages compared with the known prior art: 1. The intermediate connecting tube, lower tube, and upper tube together form a cavity for convenient injection. Two drug placement shells are then placed into the lower tube. When one drug placement shell needs to be injected, one of the pressing plates is pressed. As the pressing plate descends, it simultaneously drives one of the pressing rods, the lowering rod, and the piston plate to descend. The piston plate slides downwards within the drug placement shell to be injected, squeezing out the drug and injecting it into the patient. As one of the pressing rods descends, it moves against a blocking block to the other end. The moving blocking block eventually lands below the other pressing rod, thus preventing the other pressing rod from descending and preventing the other piston plate from squeezing out the liquid from the other drug placement shell. This prevents the patient from injecting the drugs from both drug placement shells simultaneously, improving the safety and stability of the injection.

[0016] Second, the connector can be inserted through the docking slot, and then the puncture needle is inserted into the patient's blood vessel. The liquid is then transferred to the outside of the puncture needle through the connecting hole and the transfer groove, and then to the patient's blood vessel or muscle. There is only one transfer groove, which further prevents errors during drug injection. For example, if the patient needs to inject the drug placement shell located on the left, and the position of the transfer groove is aligned with the connecting hole located on the left, even if the patient presses the press plate, the drug will not flow through the tube, and the press plate will not be able to be pressed down, further improving the injection safety of this device. When it is necessary to switch the connecting hole, the connector can be rotated to make the locking block slide in the ring groove until the locking block is locked in the locking groove. The locking force of the locking block is provided by the elastic potential energy of the locking spring, thereby improving the convenience of switching between different drugs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0018] Figure 1 This is a first front perspective view of the present invention; Figure 2 This is a perspective view of the main cross-section of the present invention; Figure 3 For the present invention Figure 2 A magnified view of a section at point A in the middle; Figure 4 For the present invention Figure 3 A magnified view of a section at point B in the middle; Figure 5 For the present invention Figure 2 A magnified view of a section at point C; Figure 6 This is a side sectional perspective view of the present invention; Figure 7 This is a second front perspective view of the present invention.

[0019] In the diagram: 1. Intermediate connecting tube; 101. Lower tube; 102. Upper tube; 103. Dosage adjustment knob; 104. Alignment plate; 2. Moving slot; 201. Pressing rod; 202. Pressing plate; 203. Lowering rod; 204. Drug placement shell; 205. Piston plate; 206. Horizontal rod; 207. Horizontal block; 208. Horizontal spring; 209. Blocking block; 3. Connecting sleeve; 301. Connecting hole; 302. Transmission... 303. Piercing needle; 304. Connecting groove; 305. Connecting joint; 306. Mounting groove; 307. Telescopic rod; 308. Snap-fit ​​spring; 309. Ring groove; 310. Snap-fit ​​block; 311. Snap-fit ​​groove; 4. Placement groove; 401. Movable tube; 402. Force-bearing block; 403. Force-bearing rod; 404. Disassembly block; 405. Movable block; 406. Movable rod; 407. Return spring; 408. Trigger block. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] The present invention will be further described below with reference to embodiments.

[0022] Example: A dual-lumen adjustable-dose pen injector, such as... Figures 1-7 As shown, the device includes an intermediate connecting tube 1, with an upper tube 102 and a lower tube 101 fixedly connected to its upper and lower ends, respectively. Two sets of pressing injection mechanisms are installed inside the intermediate connecting tube 1. Each pressing injection mechanism consists of a moving groove 2, a pressing rod 201, a pressing plate 202, a lower pressing rod 203, a drug placement shell 204, and a piston plate 205. The moving groove 2 is located on the circumferential surface of the upper tube 102. The pressing rod 201 is slidably connected inside the upper tube 102, and its lower end extends through the upper inner wall of the intermediate connecting tube 1. The pressing plate 202... 2. Fixedly connected to the circumferential surface of the pressing rod 201, the lower pressing rod 203 is integrally formed on the lower end of the pressing rod 201, the drug placement shell 204 is fixedly connected to the lower tube 101, and the lower end of the lower pressing rod 203 moves through the upper inner wall of the drug placement shell 204. The piston plate 205 is fixedly connected to the lower end of the lower pressing rod 203. Two horizontal rods 206 are fixedly connected between the inner walls of the two sides of the intermediate connecting tube 1. Horizontal blocks 207 are slidably connected to the circumferential surfaces of the two horizontal rods 206. Blocking blocks 209 are fixedly connected to the close ends of the two horizontal blocks 207.

[0023] In a specific embodiment of the present invention, the intermediate connecting tube 1, the lower tube 101, and the upper tube 102 together form a cavity for convenient injection. Then, two drug placement shells 204 are placed inside the lower tube 101. When one of the drug placement shells 204 needs to be injected, one of the pressing plates 202 is pressed. As the pressing plate 202 descends, it simultaneously drives one of the pressing rods 201, the lowering rod 203, and the piston plate 205 to descend. The piston plate 205 slides downwards within the drug placement shell 204 to be injected, thus lowering the drug placement shell 204. The medication in the 04 is squeezed out and injected into the patient. When one of the press levers 201 descends, it will move against the blocking block 209 to the other end. The moving blocking block 209 will eventually be located below the other press lever 201. At this time, the blocking block 209 can block the other press lever 201 from descending, thereby preventing the other piston plate 205 from squeezing out the liquid in the other medication container 204. This prevents the patient from injecting the medication in the two medication containers 204 at the same time, improving the safety and stability of the injection.

[0024] Please refer to the details. Figure 1-7 The lower end of the drug placement shell 204 is provided with a connection hole 301, and the lower end of the lower tube 101 is integrally formed with a connecting sleeve 3. The connecting sleeve 3 is provided with a docking groove 304, and a connector 305 is detachably connected in the docking groove 304. The lower end of the connector 305 is integrally formed with a puncture needle 303, and the upper end of the connector 305 is provided with a transmission groove 302. The inner circumferential wall of the mating groove 304 is provided with an annular groove 309. Two sets of fixing mechanisms are provided on the outer side of the mating joint 305. Each set of fixing mechanisms consists of an installation groove 306, a snap-fit ​​spring 308, a snap-fit ​​groove 311, and a snap-fit ​​block 310. The installation groove 306 and the snap-fit ​​groove 311 are respectively opened on the circumferential surface of the mating joint 305 and the inner circumferential wall of the mating groove 304. The snap-fit ​​spring 308 is fixedly connected to one side of the inner wall of the installation groove 306. The snap-fit ​​block 310 is fixedly connected to one end of the snap-fit ​​spring 308, and the snap-fit ​​block 310 is movably snapped into the snap-fit ​​groove 311.

[0025] In this embodiment: the connector 305 can be inserted through the docking groove 304, and then the puncture needle 303 is inserted into the patient's blood vessel. The liquid is then transferred to the outside of the puncture needle 303 through the connecting hole 301 and the transfer groove 302, and then transferred to the patient's blood vessel or muscle. There is only one transfer groove 302, which can further prevent errors during drug injection. For example, if the patient needs to inject the drug placement shell 204 located on the left, and the position of the transfer groove 302 is aligned with the connecting hole 301 located on the left, even if the patient presses the pressing plate 202, the drug will not be able to be pressed down because there is no flow channel, which further improves the injection safety of this device. When it is necessary to switch the connecting hole 301, the connector 305 can be rotated to make the locking block 310 slide in the annular groove 309 until the locking block 310 is locked in the locking groove 311. The locking force of the locking block 310 is provided by the elastic potential energy of the locking spring 308, thereby improving the convenience of switching between different drugs.

[0026] Please refer to the details. Figure 1-7 Two sets of disassembly mechanisms are provided on the outer side of the connecting sleeve 3. Each set of disassembly mechanisms consists of a placement groove 4, a movable tube 401, a movable block 405, a movable rod 406, a force-bearing block 402, a force-bearing rod 403, and a disassembly block 404. The placement groove 4 is opened on one side of the inner wall of the snap-fit ​​groove 311. The movable tube 401 is fixedly connected to the inner circumference of the placement groove 4. The force-bearing block 402 and the movable block 405 are slidably connected inside the movable tube 401. The force-bearing rod 403 is fixedly connected to one end of the force-bearing block 402. The disassembly block 404 is fixedly connected to one end of the force-bearing rod 403. The movable rod 406 is fixedly connected to the lower end of the movable block 405.

[0027] In this embodiment: when the snap-fit ​​block 310 is snapped into the snap-fit ​​groove 311, the connector 305 itself cannot rotate. When it is necessary to rotate the connector 305, the movable rod 406 and the movable block 405 can be pushed upwards, so that the liquid in the movable tube 401 is squeezed and moves to the other end of the movable tube 401. The force block 402, the force rod 403, and the disassembly block 404 are pushed towards the snap-fit ​​block 310. The pushing force of the trigger block 408 will determine whether the snap-fit ​​block 310 disengages from the snap-fit ​​groove 311 or from the annular groove 309. When it is necessary to push the snap-fit ​​block 310 away from the snap-fit ​​groove 311, the force can be relatively light. At this time, the snap-fit ​​groove 311 will not disengage from the annular groove 309. Then the connector 305 can be rotated to change the required connection hole 301 and medicine. When it is necessary to remove the connector 305 as a whole, the movable rod 406 can be pushed with greater force, and the disassembly block 404 can push the snap-fit ​​block 310 with greater force, so that the snap-fit ​​block 310 is pushed away from the annular groove 309, making it convenient to remove the connector 305 as a whole from the mating groove 304.

[0028] Please refer to the details. Figure 1-7 A trigger block 408 is fixedly connected to the lower end of the movable rod 406, and a reset spring 407 is sleeved on the circumferential surface of the movable rod 406. A telescopic rod 307 is fixedly connected to one side of the inner wall of the mounting groove 306, and a snap-fit ​​spring 308 is sleeved on the circumferential surface of the telescopic rod 307. Two dose adjustment knobs 103 are provided on the circumferential surface of the intermediate connecting tube 1, and an observation groove is provided at one end of the lower tube 101.

[0029] In this embodiment: when the trigger block 408 is pushed, the reset spring 407 can be squeezed to accumulate force, and through the elastic expansion of the reset spring 407, the trigger block 408 can be easily pushed to the initial position for convenient subsequent use; The telescopic rod 307 can prevent the snap-fit ​​spring 308 from bending and deforming. The dosage of this device can be adjusted by the two dosage adjustment knobs 103. The amount of drug in the two drug placement shells 204 can be observed by the observation slot.

[0030] Please refer to the details. Figure 1-7 A alignment plate 104 is fixedly connected to the circumferential surface of the lower tube 101, and a plurality of scale grooves are provided at one end of the alignment plate 104. The blocking block 209 is trapezoidal and is divided into a first inclined area, an abutment area and a second inclined area from left to right according to its shape; One end of the snap-fit ​​block 310 is bead-shaped.

[0031] In this embodiment: by cooperating with the alignment plate 104 and the observation groove, the amount of drug can be read more accurately. The two inclined areas facilitate the contact between the pressing rod 201 and the blocking block 209, allowing the blocking block 209 to move horizontally. The contact area can also contact and block another pressing rod 201. The cylindrical shape facilitates the rotation of the locking block 310 in the annular groove 309, reducing the rotational friction of the locking block 310.

[0032] Preferably, a horizontal spring 208 is fitted on the circumferential surface of the horizontal rod 206. The horizontal spring 208 is located on both sides of the horizontal block 207, and the horizontal block 207 can be reset to its initial state by means of the horizontal spring 208.

[0033] Preferably, a horizontal spring 208 is fitted onto the circumferential surface of the horizontal rod 206, and the horizontal spring 208 is located on the side of the horizontal block 207 facing away from the blocking block 209 (i.e., the side away from the blocking block 209). Preferably, one end of the horizontal spring 208 abuts against the side wall of the horizontal block 207, and the other end abuts against the retaining ring (or the inner wall boss of the intermediate connecting tube 1) fixedly connected to the end of the horizontal rod 206. When the pressing rod 201 descends and pushes the blocking block 209 and the horizontal block 207 to slide along the horizontal rod 206 through the inclined area, the horizontal spring 208 is compressed and stores energy; when the pressing rod 201 rebounds after injection, its lateral thrust on the blocking block 209 disappears, the horizontal spring 208 releases its elastic potential energy, and pushes the horizontal block 207 and the blocking block 209 back to their initial position along the horizontal rod 206, thereby releasing the obstruction of the other pressing rod 201, so that both pressing rods 201 return to the pressable state, ready for the next injection. Preferably, the two ends of the horizontal rod 206 are fixedly connected to the inner wall of the intermediate connecting pipe 1 by welding, snap-fitting or integral molding, and the retaining ring is fixed to the horizontal rod 206 by threaded connection or snap ring. The horizontal block 207 and the horizontal rod 206 are clearance fit to ensure smooth sliding. Preferably, the lower end of the pressing rod 201 is provided with a sloped surface (or wedge-shaped surface) that cooperates with the sloped area of ​​the blocking block 209. Specifically, corresponding to the left pressing rod 201, preferably, its lower end face facing the blocking block 209 is machined into an inclined surface, and the inclination angle of the inclined surface matches the inclination angle of the first sloped area of ​​the blocking block 209; corresponding to the right pressing rod 201, preferably, its lower end face facing the blocking block 209 is also machined into an inclined surface, and the inclination angle of the inclined surface matches the inclination angle of the second sloped area of ​​the blocking block 209; When one of the pressing levers 201 (e.g., the left pressing lever 201) is pressed, its lower inclined surface first contacts the first inclined area of ​​the blocking block 209. Under the action of the inclined surfaces, the downward pressing force generates a horizontal component force, driving the blocking block 209 and the horizontal block 207 to slide to the other side (right side) along the horizontal rod 206. As the blocking block 209 moves, its contact area gradually moves to a position directly below the other pressing lever 201 (the right pressing lever 201), eventually completely blocking the downward pressing path of the right pressing lever 201. Similarly, when the right pressing lever 201 is pressed, its lower inclined surface drives the blocking block 209 to move to the left through the second inclined area, eventually blocking the downward pressing path of the left pressing lever 201. Preferably, the single-channel selection function of the transfer channel 302 and the interlocking function of the blocking block 209 constitute a dual safety guarantee mechanism. When the transfer channel 302 is aligned with the connection hole 301 of a certain drug placement shell 204, even if the interlocking mechanism fails to completely block the other pressing rod 201 due to an accident, the internal liquid cannot flow out because the connection hole 301 of the other drug placement shell 204 is closed by the upper end face of the connector 305, thus forming a second barrier against mis-injection at the hydraulic level. Conversely, when the user needs to switch the injection drug, the connector 305 can be rotated to align the transfer channel 302 with another connection hole 301. At the same time, the interlocking mechanism ensures that the next pressing operation is only allowed after the pressing rod 201 corresponding to the currently selected drug chamber is pressed and the injection is completed, and then reset by the horizontal spring 208. The two work together to ensure that the dual-chamber drugs are always injected sequentially and independently, eliminating the risk of drug mixing or mis-injection due to improper operation.

[0034] Preferably, the dose adjustment knob 103 is a conventional dose setting mechanism in the field of pen syringes. Preferably, the dose adjustment knob 103 is fitted onto the circumferential surface of the intermediate connecting tube 1, and its inner wall has internal threads or ratchet teeth, cooperating with internal transmission components (such as screws, nuts, or pawls). In use, the user rotates the dose adjustment knob 103, driving the internal transmission component to advance axially, thereby limiting the downward stroke of the pressing rod 201, and thus controlling the advance distance of the piston plate 205 within the drug placement shell 204, achieving precise setting of the injection dose. Preferably, the dose adjustment knob 103 makes a "click" sound when rotated to provide auditory and tactile feedback, allowing the user to perceive the dose unit corresponding to each rotation. Preferably, the dose adjustment knob 103 can rotate bidirectionally; forward rotation increases the set dose, and reverse rotation decreases the set dose. The observation slot cooperates with the scale groove on the alignment plate 104 to visually display the currently set dose value. The operation of the dose adjustment knob 103 described above is common knowledge in the art and will not be repeated here. The improvement of this invention lies in the dual-chamber interlocking mechanism, rather than the dose adjustment mechanism itself. Therefore, the specific internal structure of the dose adjustment knob 103 can adopt any conventional design found in existing pen injectors, and is not limited here.

[0035] Preferably, all springs involved in this invention (including but not limited to horizontal spring 208, snap-fit ​​spring 308, and return spring 407) are made of fatigue-resistant alloy materials (such as stainless steel, titanium alloy, etc.) and are subjected to aging treatment or shot peening strengthening treatment to improve their stress relaxation resistance and fatigue resistance, ensuring that they can maintain stable elastic recovery force within the expected service life of the pen syringe, and avoiding loss of the proper driving or reset function due to elastic fatigue caused by long-term use. Preferably, each spring involved in this invention is equipped with a corresponding limiting structure during installation to prevent radial bending or torsional deformation during compression. Specifically, each spring is sleeved on the circumferential surface of a corresponding rod (such as horizontal rod 206, telescopic rod 307, and movable rod 406), and the inner diameter of the spring and the outer diameter of the sleeved rod are fitted with a clearance fit, so that the circumferential surface of the rod forms a radial constraint on the inner coil of the spring, thereby guiding the spring to stably extend and retract along the axial direction of the rod, ensuring the motion accuracy of related moving parts (such as blocking block 209, locking block 310, and trigger block 408) and the overall working reliability of the mechanism.

[0036] Preferably, it should be noted that, in order to solve the technical problem of narrow internal space of pen syringes and inability to use conventional tools for assembly, the assembly of the interlocking components in this embodiment is preferably carried out in the following manner: During assembly, firstly, the horizontal spring 208 is sleeved on the circumferential surface of the horizontal rod 206, so that one end of the horizontal spring 208 abuts against the retaining ring or the boss (not separately labeled in the figure) on the inner wall of the intermediate connecting tube 1 that is pre-fixed at the end of the horizontal rod 206. Then, the horizontal block 207 is slidably sleeved on the horizontal rod 206, so that the other end of the horizontal spring 208 abuts against the side wall of the horizontal block 207. Next, the two horizontal rods 206, along with the pre-installed horizontal blocks 207 and horizontal springs 208, are inserted axially into the inner cavity of the intermediate connecting tube 1 from the open assembly end (i.e., the end connected to the upper tube 102 or lower tube 101, preferably before the upper tube 102 is assembled) of the intermediate connecting tube 1. One end of the horizontal rod 206 is first embedded or abutted against a pre-set fixing groove at the far end of the inner wall of the intermediate connecting tube 1, and then the other end of the horizontal rod 206 is lowered into the corresponding fixing hole at the near end of the inner wall of the intermediate connecting tube 1, thus fixing both ends of the horizontal rod 206. Subsequently, the blocking block 209 is fixed to the near ends of the two horizontal blocks 207 by snap-fitting, welding, or fastener connection. Finally, the upper tube 102 is closed and assembled onto the upper end of the intermediate connecting tube 1, completing the secure assembly of the entire interlocking mechanism within the formed cavity. The assembly method described above, which involves inserting the entire syringe from the end of the cavity, effectively avoids the difficulty of assembling parts one by one inside a narrow cavity. It does not require changes to the overall molding process of the syringe, and is reliable in operation, making it suitable for mass production.

[0037] Preferably, regarding the precise alignment of the transmission slot 302 and the connecting hole 301, this solution achieves this through the snap-fit ​​engagement of the snap-fit ​​block 310 and the snap-fit ​​groove 311. Specifically, there are two snap-fit ​​grooves 311, spaced apart along the circumferential direction of the mating slot 304, and the positions of the two snap-fit ​​grooves 311 correspond one-to-one with the connecting holes 301 of the two drug placement shells 204. When the user rotates the mating connector 305, causing the snap-fit ​​block 310 to snap into one of the snap-fit ​​grooves 311, The transfer groove 302 is perfectly aligned and connected with the connection hole 301 of the corresponding drug placement shell 204. When the locking block 310 is rotated into another locking groove 311, the transfer groove 302 is perfectly aligned and connected with another connection hole 301. Thus, the locking engagement of the locking block 310 and the locking groove 311 simultaneously performs the dual functions of circumferential fixation of the connector 305 and rotational positioning of the transfer groove 302, ensuring that the flow channel is accurately aligned after each switch without the need for a separate positioning structure.

[0038] Preferably, in the initial state, the blocking block 209 is positioned in the middle under the action of the horizontal spring 208. When injecting the first drug: rotate the connector 305 to align the transmission groove 302 with the connection hole 301 of the target drug placement shell 204, rotate the corresponding dose adjustment knob 103 to set the dose, insert the needle, press the corresponding pressing plate 202, the pressing rod 201 moves down and pushes the blocking block 209 to the other side through the inclined surface, locking the other pressing rod 201, while the piston plate 205 squeezes out the drug. After the injection is completed, the pressing rod 201 resets, and the horizontal spring 208 pushes the blocking block 209 back to the center to unlock it. The above corresponding operation is repeated when injecting the second drug. The interlocking mechanism and the single-channel selection of the transmission groove 302 together constitute a double safety guarantee.

[0039] Working principle: The connector 305 can be inserted through the docking groove 304, and then the puncture needle 303 is inserted into the patient's blood vessel. The liquid is then transferred to the outside of the puncture needle 303 through the connecting hole 301 and the transfer groove 302, and then to the patient's blood vessel or muscle. There is only one transfer groove 302, which can further prevent errors during drug injection. For example, if the patient needs to inject the drug placement shell 204 located on the left, and the position of the transfer groove 302 is aligned with the connecting hole 301 located on the left, even if the patient presses the pressing plate 202, the drug will not be able to be pressed down because there is no flow channel, which further improves the injection safety of this device. When it is necessary to switch the connecting hole 301, the connector 305 can be rotated to make the locking block 310 slide in the annular groove 309 until the locking block 310 is locked in the locking groove 311. The locking force of the locking block 310 is provided by the elastic potential energy of the locking spring 308, thereby improving the convenience of switching between different drugs.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pen-type injector with dual-lumen adjustable dosage, comprising an intermediate connecting tube (1), characterized in that: The upper and lower ends of the intermediate connecting tube (1) are fixedly connected to an upper tube (102) and a lower tube (101), respectively. Two sets of pressing injection mechanisms are installed inside the intermediate connecting tube (1). Each pressing injection mechanism consists of a moving groove (2), a pressing rod (201), a pressing plate (202), a lower pressing rod (203), a drug placement shell (204), and a piston plate (205). The moving groove (2) is located on the circumferential surface of the upper tube (102). The pressing rod (201) is slidably connected inside the upper tube (102), and the lower end of the pressing rod (201) extends through the upper inner wall of the intermediate connecting tube (1). The pressing plate (202) is fixedly connected to... The pressing rod (203) is integrally formed on the lower end of the pressing rod (201) and attached to the circumferential surface of the pressing rod (201). The drug placement shell (204) is fixedly connected to the lower tube (101), and the lower end of the pressing rod (203) moves through the upper inner wall of the drug placement shell (204). The piston plate (205) is fixedly connected to the lower end of the pressing rod (203). Two horizontal rods (206) are fixedly connected between the inner walls of the two sides of the intermediate connecting tube (1). Horizontal blocks (207) are slidably connected to the circumferential surfaces of the two horizontal rods (206). Blocks (209) are fixedly connected to the close ends of the two horizontal blocks (207).

2. The pen injector with dual-chamber adjustable dosage according to claim 1, characterized in that: The lower end of the drug placement shell (204) is provided with a connection hole (301), and the lower end of the lower tube (101) is integrally formed with a connecting sleeve (3). The connecting sleeve (3) is provided with a docking groove (304), and a connector (305) is detachably connected in the docking groove (304). The lower end of the connector (305) is integrally formed with a puncture needle (303), and the upper end of the connector (305) is provided with a transmission groove (302).

3. The pen injector with dual-chamber adjustable dosage according to claim 2, characterized in that: The inner circumferential wall of the docking groove (304) is provided with an annular groove (309). The outer side of the docking joint (305) is provided with two sets of fixing mechanisms. Each set of fixing mechanisms consists of an installation groove (306), a snap-fit ​​spring (308), a snap-fit ​​groove (311), and a snap-fit ​​block (310). The installation groove (306) and the snap-fit ​​groove (311) are respectively opened on the circumferential surface of the docking joint (305) and the inner circumferential wall of the docking groove (304). The snap-fit ​​spring (308) is fixedly connected to one side of the inner wall of the installation groove (306). The snap-fit ​​block (310) is fixedly connected to one end of the snap-fit ​​spring (308), and the snap-fit ​​block (310) is movably snapped into the snap-fit ​​groove (311).

4. The pen injector with dual-chamber adjustable dosage according to claim 3, characterized in that: Two sets of disassembly mechanisms are provided on the outer side of the connecting sleeve (3). Each set of disassembly mechanisms consists of a placement groove (4), a movable tube (401), a movable block (405), a movable rod (406), a force-bearing block (402), a force-bearing rod (403), and a disassembly block (404). The placement groove (4) is opened on one side of the inner wall of the snap-fit ​​groove (311). The movable tube (401) is fixedly connected to the inner circumference of the placement groove (4). The force-bearing block (402) and the movable block (405) are slidably connected inside the movable tube (401). The force-bearing rod (403) is fixedly connected to one end of the force-bearing block (402). The disassembly block (404) is fixedly connected to one end of the force-bearing rod (403). The movable rod (406) is fixedly connected to the lower end of the movable block (405).

5. The pen injector with dual-chamber adjustable dosage according to claim 4, characterized in that: A trigger block (408) is fixedly connected to the lower end of the movable rod (406), and a reset spring (407) is sleeved on the circumferential surface of the movable rod (406).

6. The pen injector with dual-chamber adjustable dosage according to claim 5, characterized in that: A telescopic rod (307) is fixedly connected to one side of the inner wall of the mounting groove (306), and the snap-fit ​​spring (308) is sleeved on the circumferential surface of the telescopic rod (307).

7. The pen injector with dual-chamber adjustable dosage according to claim 6, characterized in that: The intermediate connecting tube (1) has two dose adjustment knobs (103) on its circumferential surface, and an observation groove is provided at one end of the lower tube (101).

8. The pen injector with dual-chamber adjustable dosage according to claim 7, characterized in that: An alignment plate (104) is fixedly connected to the circumferential surface of the lower tube (101), and one end of the alignment plate (104) is provided with multiple scale grooves.

9. The pen injector with dual-chamber adjustable dosage according to claim 8, characterized in that: The blocking block (209) is trapezoidal and is divided into a first inclined area, an abutment area and a second inclined area from left to right according to its shape.

10. The pen injector with dual-lumen adjustable dosage according to claim 9, characterized in that: One end of the snap-fit ​​block (310) is bead-shaped.

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