WO1999021597A1

WO1999021597A1 - Device for administering therapeutic substances with power-operated syringe

Info

Publication number: WO1999021597A1
Application number: PCT/CH1998/000438
Authority: WO
Inventors: Jean Claude Berney
Original assignee: Njc Innovations
Priority date: 1997-10-27
Filing date: 1998-10-13
Publication date: 1999-05-06
Also published as: FR2770136A1; FR2770136B1

Abstract

The invention concerns a device for administering therapeutic substances with power-operated syringe, comprising: a syringe module including a syringe body (1), a plunger (2) capable of sliding inside said body and means for driving linearly said plunger comprising a guide screw (3) integral with the plunger and an actuating part (4) with a nut (5) concentric with said guide screw and co-operating with it; a motor module for driving in rotation said actuating part; and means for coupling said motor module with said syringe module. The device is characterised in that said coupling means comprise a rotating member (14) forming part of said motor module, driven by it and provided with a central opening for receiving said actuating part upper section (4a), and means for making said rotating member co-operate with said upper section when the two modules are coupled, consisting of two corresponding gear teeth one formed in said member central opening and the other in said upper section periphery.

Description

DEVICE FOR ADMINISTERING THERAPEUTIC SUBSTANCES

MOTORIZED SYRINGE

The present invention relates to a device for administering therapeutic substances with a motorized syringe.

In the field of medicine, more and more treatments use chronotherapy, that is to say a distribution of therapeutic substances slow and regular over time.

To carry out this distribution, several systems can be used. The most common is the peristaltic pump, some models of which can be worn directly by the patient. These are sophisticated means which are relatively expensive and which require special conditioning of the therapeutic substances.

There are, moreover, syringe pumps which use normal syringes which can be filled in the usual way by nursing staff. Most of these syringe pumps are table models powered by the sector and are therefore unsuitable for portable applications.

Patent CH 685,461, on the other hand, relates to a syringe pump of small dimensions which can easily be carried by the patient. It includes an autonomous motor module fitted with linear drive means enabling the plunger of the syringe to be pushed. This system however has two major drawbacks. After each use, it is necessary, in fact, to return the linear drive means of the piston to the starting position, a relatively long operation and which requires special means. Furthermore, it is not provided no way to easily and quickly fill the syringe.

To facilitate the work of nursing staff, patent application PCT / CH96 / 00221 proposes two important improvements. On the one hand, the linear drive means of the piston are separated from the motor module and are integrated directly into the syringe. Therefore, they are used only once and discarded with the syringe after use. It is therefore no longer necessary to replace them as before. On the other hand, a removable zipper makes it possible to fill the syringe very simply, in the same way as a conventional syringe. In practice, we realize that a third element is of paramount importance for the proper functioning of the system. This is the coupling between the motor module and the linear drive means integrated in the syringe which are only described schematically in the patent application mentioned above. It is, in fact, necessary to have an easy and precise positioning of the syringe and a perfect alignment of the coupling elements, to avoid friction which could very quickly reduce the transmission efficiency, or even block the system.

The present invention provides improvements to existing syringe pumps, which allow simple and precise placement of the syringe, ensure high quality and high coupling efficiency and, in general, improve the operational safety of the system. .

More specifically, the invention relates to a device for administering therapeutic substances with a motorized syringe, of the type comprising:

a syringe module comprising a syringe body, a piston capable of sliding inside said body and linear drive means of said piston comprising a lead screw integral with the piston. and an actuating part with nut concentric with said lead screw and cooperating with it;

- a motor module for driving in rotation of said actuating part; and - coupling means between said motor module and said syringe module.

According to the invention, this device is characterized in that said coupling means comprise: - a rotary member forming part of said motor module, driven by it and provided with a central opening intended to receive the upper part of said part d 'actuation; and

- Means for making said rotary member and said upper part cooperate during the coupling of the two modules.

According to an advantageous embodiment, the means for making said rotary member and said upper part cooperate consist of two corresponding teeth formed one in the central opening of said member and the other at the periphery of said upper part. According to another advantageous embodiment, these means consist of a coil spring mounted on said member and of internal diameter substantially equal to the external diameter of said upper part.

Preferably, said rotary member is mounted on a ball bearing, the end of the upper part of the actuating part is conical so as to facilitate its introduction into the central opening of said rotary member, and said coupling means have, in each of the two modules, elements cooperating with each other to constitute a bayonet system. It is advantageous that the motor module includes guide means allowing the automatic centering of said actuating part in the central opening of said rotary member. These guide means may comprise a ring with an outside diameter slightly smaller than the inside diameter of the syringe body and taking place in the upper end of the latter.

Preferably, the motor module comprises a receptacle portion for the syringe body, a switch authorizing its operation only if the elements of the bayonet system are assembled and programming means which are arranged on said receptacle portion so as to be hidden by the syringe body when the two modules are coupled.

The syringe module advantageously includes means for preventing the rotation of the lead screw.

Finally, according to a particularly advantageous embodiment, the device comprises a pull tab, one end of which can be removably coupled to the drive means of the piston in order to move it manually to carry out the operations of filling the syringe body, before the replace, during commissioning, with the motor module.

The invention and its advantages will appear better on reading the description which follows, made with reference to the appended drawings in which:

- Figures 1a, 1b and 1c show, in axial section, a syringe module according to the invention with its linear drive means and its removable zipper, respectively before filling, after filling and before use; - Figure 2 shows, in axial section, the upper part of the engine module and its coupling means with the linear drive means of the piston;

- Figures 3a and 3b are respectively the front and side views, in axial section, of the complete motor module with its control electronics and a syringe module in place;

- Figures 4a and 4b show how to set up the syringe module on the motor module;

- Figures 5a and 5b are respectively the front and side views of the part of the motor module comprising the control electronics and its programming means;

- Figures 6a and 6b show two possible embodiments of the coupling means between the motor module and the linear drive means; finally,

- Figure 7 shows, in axial section, an anti-rotation system of the linear drive means.

FIG. 1 shows a syringe comprising a standard syringe body 1, with a capacity, for example, of 20 cm ³ , inside which a piston can slide with its seal 2. A lead screw 3 is integrally mounted on the piston 2. In general, the friction of the seal on the syringe body 1 is sufficient to prevent rotation of the piston and therefore that of the lead screw 3. If this is not the case, it is possible to add an anti-rotation system which will be described later. The lead screw 3 is arranged in the center of a tubular actuating part 4 which comprises a nut 5 cooperating with the lead screw. The upper part 4a of this part has a smaller diameter, thus defining a stop 4b. single piece. Its point 4c has, moreover, a conical shape. In practice, the part 4 and the nut 5 are advantageously molded in one piece. It is understood that by rotating the nut 5 by means of the actuating part 4, the lead screw 3, which cannot rotate, will move and push the piston 2 with which it is integral. The lead screw and the nut actuation part constitute the linear drive means of the piston. These are inexpensive items intended for single use and discarded after use.

The syringe also includes a pull tab 6, visible in FIGS. 1a and 1b, fixed, in this example, by screwing to the end of the mother screw 3 and two diametrically opposite ears 7 which serve to couple it to the motor module. The pull tab 6 makes it possible to fill the syringe in a completely usual way by pulling on this pull tab. There is therefore no particular preconditioning of the therapeutic substance. When the syringe body 1 is correctly filled (FIG. 1 b) and any air bubbles have been eliminated, the pull tab 6 is removed. Before fitting onto the motor module, the syringe therefore presents itself, as shown in FIG. 1 c, with part of the linear drive means which protrude. It will be noted that these means only comprise two elements, lead screw and actuation part, instead of three in the PCT patent application cited above. As a result, their length is greater, but the particular configuration of the device according to the invention makes it possible to maintain the overall length at an equivalent value.

FIG. 2 schematically represents the upper part of the engine module and the coupling means between it and the linear drive means of the piston. This motor module includes, mounted at inside a support 11, a reduction motor 10. This reduction motor comprises a rapidly rotating axis on which is fixed a visual indicator 12 making a revolution in a few tens of seconds and allowing the user to check whether the engine is running. The reduction motor 10 also comprises a slowly rotating axis on which is fixed a pinion 13 driving a wheel 14 mounted on a ball bearing 15 driven into a cylindrical hole in the support 11. This ball bearing can be replaced by simpler means , but it has the advantage of having very low friction and of accepting high axial tensions. The wheel 14 and the bearing 15 have a central opening in which the upper part 4a of the actuating part 4 is housed. The conical point 4c of the latter facilitates its introduction into the central opening of the wheel 1 and of the bearing 15.

We see that the lead screw 3 is then completely through and practically defines the overall length of the device. As the height of the engine module does not intervene, contrary to what was the case in the PCT patent application cited above, the total length of the system remains substantially the same.

For the device to function, it is necessary that after the coupling of the two modules, the wheel 14 rotates the actuating part 4. This drive can be done in different ways which will be developed in FIG. 6. To ensure the centering and fixing the syringe, there is provided a ring 16 driven into the same cylindrical hole as the bearing 15. This ring has an outside diameter very slightly less than the inside diameter of the syringe body 1, which allows to center it ci when the syringe is in place. In addition, the support 11 has recesses 11 a shaped and dimensioned to receive and trap the two ears 7 of the syringe body 1 by a bayonet assembly by making it perform a rotation of a quarter turn. Once correctly set up, according to a procedure which will be described later, the syringe module is perfectly centered by the ring 16 and held in place by the bayonet assembly. pressing on the rotating part of the bearing 15, this part cannot therefore move upwards and can therefore only rotate. When driven by the motor 10 via the pinion 13 and the wheel 14, its nut 5 rotates and thus causes the linear displacement of the lead screw 3 by a distance proportional to the number of turns of the wheel 14. It should be noted that this advance is extremely slow, since, in chronotherapy, an infusion is sought over several hours, even over several days.

A window 17 formed in a protective cover 18 of the engine module makes it possible to see the indicator 12 and thus to ensure the operation of the device.

Figures 3a and 3b are respectively front and side views of the device according to the invention. It can be seen that the motor module has a rear part 21 which extends over the entire length of the syringe body and comprises, inter alia, control electronics 22 with its battery 23 and a tab 24 enabling the assembly to be fixed to the belt or on a harness. This rear part also serves as a receptacle for the syringe thanks to its internal face 25 and reinforcements provided at its base to form a ring 26.

Once in place, the syringe body 1 is thus maintained in a correct position by:

- The bayonet assembly formed by the ears 7 and the clearances 11 a; - the ring 16; the support face 25 and the ring 26. The control electronics 22 comprises a micro-switch 30 positioned so as to be actuated by one of the ears 7 of the syringe body 1. This switch authorizes the engine module to operate only when the syringe module is correctly put in square.

Figure 4 shows how to set up the syringe module on the motor module. The syringe body 1 is first introduced, at an angle of about 45 degrees, into the ring 26 of the rear part 21 of the motor module, then tilted until it comes into contact with the face d 'support 25 (Figure 4a). The syringe then being perfectly held laterally in the four directions perpendicular to its axis, it suffices to push it upwards (FIG. 4b) until the bearing 4b abuts against the bearing 5, then to rotate it by a quarter turn to block the bayonet. To decouple the two modules, simply repeat the above operations in reverse order.

The configuration described makes it possible to set up the syringe with all the desired precision, with perfect centering and alignment, without taking any particular precautions, the microswitch 30 guaranteeing that the device is only put into operation if everything is in good position. These elements are important insofar as they facilitate the work of the nursing staff, whether it is the ease of filling, the simplicity of fitting the syringe and safety in terms of the putting into service of the device.

FIG. 5 represents the rear part 21 of the engine module comprising the control electronics 22 and its programming means. This electronics allows, by means well known to those skilled in the art, to define several speeds of rotation of the motor 10, corresponding for example to flow rates of 20cm ³ / 25h, 20cm ³ / 50h, 20cm ³ / 100h or 20cm ³ / 200h. It is also important that only caregivers have access to the programming of these different rates and that the patient can in no case modify them on his own during treatment. The configuration of the system according to the invention makes it possible to easily obtain such protection. In FIG. 5, it can be seen that the bearing face 25 includes a linear selector 31 for the selection of the different flow rates. This selector is placed so that it is completely hidden by the syringe body when it is in place. The patient would therefore have to withdraw the syringe if he wanted to change the programming. Furthermore, by withdrawing the syringe, the motor will stop, due to the deactivation of the microswitch 30, and can only start again if a restarting routine is known, known only to nursing staff.

Figure 6 shows some details of the means for coupling between the motor module and the actuating part 4 of the syringe module. According to the embodiment of FIG. 6a, the wheel 14 has an internal toothing 32 which cooperates with a corresponding toothing of the upper part 4a of the actuating part 4. According to the embodiment of FIG. 6b, a coil spring 34 mounted on the wheel 14. The inside diameter of this spring is equal to the outside diameter of part 4a of the actuating part 4. When the syringe is put in place, this spring slightly tightens part 4a. It is actually a one-way drive. In a direction of rotation, the spring 34 tightens further and the actuating part is completely integral with the wheel 14 and rotates with it. In the other direction, the spring 34 loosens; the actuating part 4 therefore becomes free and can rotate independently of the wheel 14. This configuration is advantageous insofar as it facilitates the positioning of the syringe. In addition, a cover 35 fixed on the wheel 14 ensures a sealed separation between the motor module and the outside when the syringe module is removed and the central opening of the wheel 14 is no longer closed by the actuator 4. FIG. 7 shows an anti-rotation system for the linear drive means of the syringe piston. Indeed, in certain extreme cases, the friction of the piston seal 2 on the syringe body 1 is insufficient to guarantee that the piston, and therefore the lead screw 3, does not rotate at all. A simple way to avoid this rotation is to fix two rollers 36 and 37 at the respective ends of two forks 38 and 39 fixed on the piston. When the latter moves linearly, the rollers rotate and their friction is negligible. On the other hand, when the piston turns, the rollers move laterally and have a high resistance. Everything is made of plastic at low cost.

There are, of course, other possible embodiments of the device according to the invention, but their description would not provide any new elements for its understanding.

Claims

1. Device for administering therapeutic substances with a motorized syringe, comprising:

- a syringe module comprising a syringe body (1), a piston (2) capable of sliding inside said body and linear drive means of said piston comprising a lead screw (3) integral with the piston and a part actuator (4) with nut (5) concentric with said mother screw and cooperating with it;

a motor module for the rotary drive of said actuating part; and

- coupling means between said motor module and said syringe module; characterized by the fact that said coupling means comprise:

- a rotary member (14) forming part of said motor module, driven by it and provided with a central opening intended to receive the upper part (4a) of said actuating part; and

2. Device according to claim 1, characterized in that the means for making said rotary member (14) and said upper part (4a) cooperate are constituted by two corresponding teeth formed one (32) in the central opening of said organ and the other at the periphery of said upper part.

3. Device according to claim 1, characterized in that the means for making said rotary member (14) and said upper part (4a) cooperate consist of a coil spring (34) mounted on said member and of internal diameter substantially equal to the external diameter of said upper part.

4. Device according to one of the preceding claims, characterized in that said rotary member is mounted on a ball bearing (15).

5. Device according to one of the preceding claims, characterized in that the end (4c) of the upper part (4a) of said actuating part is conical so as to facilitate its introduction into the central opening of said member rotary.

6. Device according to one of the preceding claims, characterized in that said coupling means comprise, in each of the two modules, elements cooperating with each other to form a bayonet system (7, 11a).

7. Device according to one of the preceding claims, characterized in that the motor module comprises guide means allowing the automatic centering of said actuating part in the central opening of said rotary member.

8. Device according to claim 7, characterized in that said guide means comprise a ring (16) of outside diameter slightly smaller than the inside diameter of the syringe body and which takes place in the upper end thereof .

9. Device according to one of the preceding claims, characterized in that the motor module comprises a portion (21) forming a receptacle for the syringe body.

10. Device according to claim 6, characterized in that the motor module comprises a switch (30) authorizing its operation only if the elements of said bayonet system are assembled.

11. Device according to claim 9, characterized in that the motor module comprises programming means (31) which are arranged on said receptacle portion (21) so as to be hidden by the syringe body when the coupling of the two modules are produced.

12. Device according to one of the preceding claims, characterized in that the syringe module comprises means (36, 37, 38, 39) for preventing the rotation of the lead screw.

13. Device according to one of the preceding claims, characterized in that it comprises a pull tab (6) one end of which can be removably coupled to said piston drive means in order to move it manually to carry out the operations of filling the syringe body before replacing it, during commissioning, by said motor module.