RU2357761C1 - Device of medication injection dosage - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: invention concerns medical equipment, particularly devices of medication injection dosage, and can be applied by patient in self-treatment, e.g. for diabetes. Device for medication injection dosage includes cartridge, case, medication cartridge holder mounted on case, medication dosage device in the form of rod with piston for medication expression from cartridge, including nut element and matching threaded part, and device of rod movement during injection. Additionally device includes external pressure device for obtainment of threaded engagement between nut element and matching threaded part, and device of nut element and matching threaded part blocking. Matching threaded part is made on rod which can perform lengthwise travel against case. Rod travel device is made in the form of hub connected to rotation drive. Nut element in the form of disc sector with one end suspended loosely on pin is mounted on hub end and can rotate around hub. External pressure device is made in the form of spring wire contacting nut element and hub.

EFFECT: enhanced precision of administration dosage of fluid medications from removable cartridge; simplified construction, due to implementation of combined function of dosage and piston rod release by one device (for fast cartridge replacement); simplified user operation due to reduced number of manipulations.

4 cl, 4 dwg

Description

The present invention relates to medical equipment, in particular to devices for dosed injection of a medicinal product, and can be used by a patient for self-treatment, for example, diabetes mellitus.

Piston type devices, the so-called metering syringes with a screw-nut type micro-feeding mechanism, are most widely used for the dosed supply of liquid substances.

In known constructions, a split (disengaged) nut is used, which can remain engaged with the screw by external pressure on it and disengage when external pressure is relieved.

Known syringe dispenser for storage and metered supply of viscous materials, including a housing mounted on it a holder of a cartridge with the drug, the dosing mechanism of the drug and the mechanism for moving the rod during screw-nut injection (see publ. Application of the Russian Federation No. 92008124 according to class A61M 5/32, 1992).

However, the main disadvantage of the known device is the inability to quickly and easily change the cartridge.

The closest in technical essence to the proposed technical solution is a device for a metered injection of a drug, consisting of a housing mounted on it a holder of a cartridge with a drug, a dose metering mechanism of a drug made in the form of a rod with a piston designed to squeeze the drug from the cartridge, and containing a nut element with a protrusion designed to lock it, and a mating threaded part, an external pressure mechanism designed to create ezbovogo engagement between the nut member and the female screw portion, and the rod advancing mechanism during injection (see. Russian patent №2173180 tml. A61M 5/24, 1996 YG).

The disadvantages of the known solutions are:

- Insufficient dosing accuracy, which is determined by the thread pitch on the spindle and the diameter of the head rotating the spindle. With the actual dimensions of the syringe, and hence the values of these parameters, moving the cartridge piston with the help of the head manually can amount to only tenths of the thread pitch, which in some cases is not enough.

- The difficulty of bringing the rod to the piston of the cartridge in the case of using a cartridge filled with a drug is only half because when replacing a cartridge, the stem is always retracted to its initial position corresponding to a fully filled cartridge.

- Universality of the design, as there are no means in it that would protect the dispensing mechanism from breakage when they try to make an injection without a needle.

- The complexity of the design, because it is necessary to ensure the movement of the nut in the housing in the longitudinal direction, and the impossibility of turning it relative to the housing. In this case, it is required to provide external pressure on the two halves of the nut along the entire length of the housing when the nut moves along the spindle.

- The complexity of the manufacture and assembly of the structure due to the large number of locking elements, longitudinal guide grooves and protrusions.

- Providing external pressure on the two halves of the nut is made along the entire length of the housing when the nut moves along the spindle.

- The complexity of manufacturing a flexible rod.

The problems solved by the invention are the creation of a device that allows to provide:

increased accuracy of the dosed supply of liquid drugs from a replaceable cartridge;

simplification of the design by combining the functions of the metering mechanism and the piston rod release mechanism (for quick cartridge change) in one mechanism;

simplification of the user’s work with the device by reducing the number of manipulations.

The technical result is achieved by creating a device for dosed injection of a medicinal product, consisting of a cartridge, a housing, a holder for a cartridge of a drug mounted on it, a mechanism for dispensing a dose of a drug made in the form of a rod with a piston designed to squeeze the drug from the cartridge, and containing a nut element and mating threaded part, and the mechanism for moving the rod during injection, which according to the invention contains an external pressure mechanism designed to create threaded engagement between the nut element and the mating threaded part, and locking mechanisms of the nut element and the mating threaded part, and the mating threaded part is made on a rod mounted with the possibility of longitudinal movement relative to the housing, and the rod advancement mechanism is made in the form of a sleeve associated with its drive rotation, while at the end of the sleeve with the possibility of rotation relative to it, a nut element is installed, which is a sector of the disk, one end of which is freely suspended on the pin, and the fur The bottom of the external pressure is made in the form of a spring wire in contact with the nut element and the sleeve.

The installation of locking mechanisms for the nut element and the mating threaded part on the housing allows to simplify the design.

The implementation of the locking mechanism of the nut element in the form of an elastic plate, which is in contact with the protrusion of the nut element, allows for the rapid change of the cartridge by quickly releasing the rod from the threaded engagement.

The implementation of the locking mechanism of the mating threaded part in the form of a pin that engages with a longitudinal groove made on the rod, eliminates the rotation of the rod and ensures its longitudinal movement.

The implementation of the external pressure mechanism in the form of a spring wire in contact with the nut element and the sleeve, allows you to create external pressure only in the place of interaction of the nut and the sleeve, which greatly simplifies the process.

Patent studies have shown that technical solutions with the indicated set of essential features are not known in similar devices for dosed injection of a drug, i.e. the proposed solution meets the criterion of "novelty."

We believe that the information set forth in the application materials is sufficient for the practical implementation of the invention.

The essence of the proposed device for a metered injection of a drug is illustrated by the following description and drawings, where:

figure 1 shows the appearance of a device for dosed injection of a drug;

figure 2 shows the locking mechanism of the mating threaded part;

figure 3 shows the working position of the sleeve and nut;

figure 4 shows the relative position of the elastic plate and the bent end of the spring wire at the moment of closest approximation to each other.

A device for a metered injection of a drug consists of a housing 1, a holder 2 of a cartridge with a drug mounted on it, a dose metering mechanism of the drug, made in the form of a rod 3, designed to extrude the drug from the cartridge using a piston 4, and containing a nut element 5 with a protrusion 6, intended to lock it, and the mating threaded part 7, an external pressure mechanism designed to create a threaded engagement between the nut element and the mating threaded part, anizma advancement rod during injection, the locking mechanisms of the nut element and female screw portions which are mounted on the housing 1.

In this case, the mating threaded part 7 is made on the rod 3, which is mounted with the possibility of longitudinal movement relative to the housing 1.

The rod 3 has a longitudinal groove 8, designed to prevent its rotation.

The rod advancement mechanism is made in the form of a sleeve 9, connected with its rotation drive 10 (not shown) and mounted on the end face of the sleeve with the possibility of rotation of the nut element 5 relative to it.

In this case, the sleeve 9 can be installed in the holes of the support plates 11 and 12, mounted on the bottom wall of the housing 1, a hole is made in it in the longitudinal direction along which the rod 3 can move freely. The sleeve 9 itself cannot move in the longitudinal direction.

The nut element 5 is a sector of a disk with a thread, one end of which is freely suspended on a pin 13, pressed into the sleeve 9. A transverse cutout (not shown) is made in the sleeve, allowing the thread of the sector to engage with the reciprocal thread of the rod 3. Engagement is provided by an external mechanism pressure, made in the form of a spring wire 14 in contact with the nut element 5 and the sleeve 9.

The proposed device has a locking mechanism for the nut element, which can be made in the form of an elastic plate 15, which is in contact with the protrusion 6 of the nut element.

One of the options for the location of the locking mechanism of the nut element can be performed, for example, as follows.

Across the sleeve 9 opposite the nut element 5, an elastic plate 15 is fixed at one end to the bottom wall of the housing, the other (free) end of the plate (in the position of the sleeve with the nut element shown in FIG. 3) is located opposite the protrusion 6 of the nut element 5.

In the protrusion 6, a recess 16 can be made so that the plate does not slide off the surface of the protrusion when pressing the nut element on the end of the plate.

The free end of the plate is located at such a height and with such a lateral displacement relative to the center of the nut that it does not abut against the bent end of the spring wire 14 in the position of the sleeve with the nut shown in Fig. 4.

The proposed device also has a locking mechanism for the mating threaded part, made in the form of a pin 17 that engages with a longitudinal groove 8 made on the rod.

The drive rotation of the sleeve can be made in the form of a gear 18, placed on the sleeve and engaging with a gear 19 (not shown), located on the output shaft of the reduction speed reducer 20 with a large gear ratio. The input shaft of the gearbox can be rotated by manual and / or electromechanical drive. For manual rotation, a handle 21 is used, which is opposite the input shaft of the gearbox and rotates it through the friction joint 22. An electromotor 23 is used as an electromechanical drive. A speed counter 24 with a reset is located on the input shaft of the gearbox, which can be either mechanical or electronic.

The work of the proposed device is as follows.

The cartridge is inserted into the holder 2 from the end of the housing and fixed in it using the head 25, screwed into the housing 1.

The proposed device is ready for dosed administration of the drug.

Further, by rotating (manually or using an electromechanical drive) the input shaft of the gearbox, causing the sleeve 9 to rotate with the nut element 5 clockwise (looking at the end face of the sleeve from the nut side), since the thread of the nut element 5 is in engagement with the mating thread of the rod 3 under the pressure of the spring wire 14, and the plate 15 does not prevent the rotation of the nut with the sleeve, the rod 3 presses on the piston 4 of the cartridge. The rod moves along the thread in the longitudinal direction, since its rotation is prevented by a pin 17, which engages with the longitudinal groove 8 in the rod. As a result, a dose corresponding to the readings of the revolution counter is supplied.

If you need to change the cartridge by rotating the input shaft of the gearbox, causing the sleeve 9 to rotate counterclockwise, release the rod 3 from the threaded engagement to allow the rod 3 to move freely in the longitudinal direction.

This happens as follows.

When the free end of the plate abuts against the recess 16 in the protrusion 6 of the nut element 5, with a further rotation of the sleeve 9, the nut element 5, moving on the pin 13, moves away from the rod 6, the nut thread disengages from the rod thread.

The nut element abuts against the inner side surface of the housing 1 with its outer side, preventing further rotation of the sleeve 9.

This moment is determined by the increased force on the input shaft of the gearbox.

When removing the force on the input shaft of the gearbox, the nut element remains in the indicated position, since the pressure of the spring wire 14 on the nut element causing rotation of the sleeve 9 is not enough to turn the gears of the gearbox on the output shaft side due to the large gear ratio of the gearbox and, accordingly, the large resulting rest friction force caused by at least the presence of rest friction force on the input shaft of the gearbox and on the axes of the intermediate gears, especially those closest to the input shaft of the gearbox.

After releasing the stem 3 from the threaded engagement, the drug cartridge can be inserted.

It should be noted that the rod 3 never protrudes beyond the cartridge compartment, therefore, when changing the cartridge there is no danger of breaking or bending the rod in the transverse direction.

After installing the drug cartridge without a needle (or catheter) and fixing it in the body using the head 25, if the cartridge is completely filled with medicine, the rod will be inserted into the sleeve until it stops and you can put the device into dose delivery mode. If the cartridge is not completely filled with medicine, then turn the device with the cartridge down. Then the rod 3 slides down and rests against the piston 4 of the cartridge. It is in this position that the device must be put into the dose delivery mode.

The proposed device is transferred to the dose delivery mode by rotating the input shaft of the gearbox, causing the sleeve 9 to rotate clockwise. When this element of the nut 5 disengages from the free end of the elastic plate 15, the thread of the nut engages with the thread of the rod and the device is ready for dose.

This moment can be determined by the readings of the revolution counter 24, since the number of revolutions from the start of rotation to this moment is known, or by the increased force on the input shaft of the gearbox, since the liquid drug will not leak out of the cartridge without a needle (or catheter) and piston cannot be pressed into the cartridge.

Friction connection 22 for manual drive serves to avoid damage to the metering mechanism in cases of increased force on the input shaft of the gearbox. In this case, the rotation of the handle is not transmitted to the input shaft of the gearbox and the changes in the counter readings are stopped. When using an electromechanical drive, it is always possible to limit the power of the drive to prevent breakage of the mechanism in these cases.

In the case when the force on the input shaft of the gearbox increases due to the absence of a needle or kink of the catheter, there is another property of the mechanism that protects it from breakage. When the input shaft of the gearbox rotates, causing the sleeve 9 to rotate with the nut element 5 clockwise, the pressure of the nut element 5 on the rod 3 increases (and vice versa), which becomes sufficient to move the nut from the rod, overcoming the resistance of the spring wire. The rod will disengage from the nut element and the thread on them will not be destroyed.

A prototype of the proposed device was manufactured and tested.

Tests have shown the operability of the device. The release of the rod in the proposed device occurs when the sleeve is rotated by only 10-15 degrees.

Claims (4)

1. A device for a metered injection of a drug, consisting of a cartridge, a housing, a cartridge holder for a drug mounted on it, a drug dose dispensing mechanism made in the form of a rod with a piston designed to extrude the drug from the cartridge, and containing a nut element and a threaded response part, and the mechanism for moving the rod during injection, characterized in that it contains an external pressure mechanism designed to create a threaded engagement between the nut element ki and the mating threaded part, and locking mechanisms of the nut element and the mating threaded part, and the mating threaded part is made on a rod mounted with the possibility of longitudinal movement relative to the housing, and the rod advancement mechanism is made in the form of a sleeve connected with its rotation drive, while the end face of the sleeve can be rotated relative to it with a nut element representing a sector of the disk, one end of which is freely suspended on the pin, and the external pressure mechanism is made in the form of a spring s wire contacting member and the sleeve nut. 2. The device for dosed injection according to claim 1, characterized in that the locking mechanisms of the nut element and the mating threaded part are mounted on the housing. 3. The device for dosed injection according to claim 1, characterized in that the locking mechanism of the nut element is mounted on the housing and is made in the form of an elastic plate that is in contact with the protrusion of the nut element. 4. The device for dosed injection according to claim 1, characterized in that the locking mechanism of the mating threaded part is made in the form of a pin that engages with a longitudinal groove made on the rod.

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