PORTABLE PUMP FOR DRUG INFUSION THROUGH A SYRINGE REMOVABLY ENGAGED IN THE PUMP

Abstract

Portable pump (11) for drug infusion through a syringe (SR) removably engaged in the pump, said pump comprising an electromechanical unit (13) having a rod (15) which is longitudinally slidable within a guide member (17) and capable of exerting an axial thrust onto the plunger (SF) of the syringe engaged in the pump, wherein said rod (15) and said guide member (17) have a non-circular cross-section, whereby rotation of the rod (15) relative to the guide member (17) is prevented.

Claims

1. A portable pump (11) for drug infusion through a syringe (SR) removably engaged in the pump, said pump comprising an electromechanical unit (13) having a rod (15) which is longitudinally slidable within a guide member (17) and capable of exerting an axial thrust onto the plunger (SF) of the syringe engaged in the pump, characterized in that said rod (15) and said guide member (17) have a non-circular cross-section, whereby rotation of the rod (15) relative to the guide member (17) is prevented.

2. The portable pump according to claim 1, wherein said non-circular cross-section is an oval or elliptical cross-section or a cross-section comprising at least one curved portion and at least one rectilinear portion.

3. The portable pump according to claim 1, wherein said rod (15) comprises an axial cavity (19) having at least one open base (19a) and adapted to receive a rotatable screw (21) actuated by an electric geared motor (23) belonging to said electromechanical unit (13) and engaged in an internally threaded nut or bushing (27) housed within said cavity (19) of the rod (15) at said open base (19a).

4. The portable pump according to claim 1, wherein said electromechanical unit (13) comprises an electric geared motor (23) having a driving shaft (25) provided with a pinion (29a) which engages into a toothed gear wheel (29b) fixed to the base of said screw (21), said electric geared motor being adapted to cause, through coupling between the pinion and the toothed gear wheel, rotation of the screw (21) in both directions and consequent sliding back and forth of the rod (15), and wherein said rod (15) having non-circular cross-section is oriented so as to minimize the distance between said rod (15) and the geared motor (23), without any interference between said rod (15) and the geared motor (23) over the entire longitudinal sliding movement of the rod (15).

5. The portable pump according to claim 1, wherein said pump further comprises a casing (31) made of plastic material and defining therein a chamber (33) housing the electromechanical unit (13), and wherein said guide member (17) forms a single body with said casing (31).

6. The portable pump according to claim 5, wherein said guide member (17) extends longitudinally outside the casing (31) and comprises an annular gasket (39) adapted to exert a hydraulic tight-fit action against the outer surface of the rod (15).

7. The portable pump according to claim 6, wherein said gasket (39) is housed in an annular cavity (41) radially open towards the inside of the cavity (17a) of the guide member (17) and longitudinally open outside the guide member (17), and wherein said guide member (17) further comprises a locking cap (43) preventing the gasket (39) from slipping out of said annular cavity (41).

8. The portable pump according to claim 1, wherein said guide member (17) is surrounded by an engaging ferrule (35) for the open base of a syringe (SR) for drug infusion, whereby, when the syringe (SR) is engaged in the ferrule (35), the guide member extends over a portion of the length of the hollow body of the syringe (SR).

9. The portable pump according to claim 1, wherein the rod (15) comprises an end portion or pusher (45) provided with an annular portion (45a) radially extending towards the outside of the rod (15) and with a longitudinal portion (45b) axially extending from said annular portion (45a).

10. The portable pump according to claim 5, wherein said electromechanical unit (13) is supported by a support structure (51) made of metal and comprising a base plate (53) and a frame (55) attached to the plate (53).

11. The portable pump according to claim 2, wherein said rod (15) comprises an axial cavity (19) having at least one open base (19a) and adapted to receive a rotatable screw (21) actuated by an electric geared motor (23) belonging to said electromechanical unit (13) and engaged in an internally threaded nut or bushing (27) housed within said cavity (19) of the rod (15) at said open base (19a).

12. The portable pump according to claim 2, wherein said electromechanical unit (13) comprises an electric geared motor (23) having a driving shaft (25) provided with a pinion (29a) which engages into a toothed gear wheel (29b) fixed to the base of said screw (21), said electric geared motor being adapted to cause, through coupling between the pinion and the toothed gear wheel, rotation of the screw (21) in both directions and consequent sliding back and forth of the rod (15), and wherein said rod (15) having non-circular cross-section is oriented so as to minimize the distance between said rod (15) and the geared motor (23), without any interference between said rod (15) and the geared motor (23) over the entire longitudinal sliding movement of the rod (15).

13. The portable pump according to claim 2, wherein said pump further comprises a casing (31) made of plastic material and defining therein a chamber (33) housing the electromechanical unit (13), and wherein said guide member (17) forms a single body with said casing (31).

14. The portable pump according to claim 3, wherein said pump further comprises a casing (31) made of plastic material and defining therein a chamber (33) housing the electromechanical unit (13), and wherein said guide member (17) forms a single body with said casing (31).

15. The portable pump according to claim 4, wherein said pump further comprises a casing (31) made of plastic material and defining therein a chamber (33) housing the electromechanical unit (13), and wherein said guide member (17) forms a single body with said casing (31).

16. The portable pump according to claim 2, wherein said guide member (17) is surrounded by an engaging ferrule (35) for the open base of a syringe (SR) for drug infusion, whereby, when the syringe (SR) is engaged in the ferrule (35), the guide member extends over a portion of the length of the hollow body of the syringe (SR).

17. The portable pump according to claim 3, wherein said guide member (17) is surrounded by an engaging ferrule (35) for the open base of a syringe (SR) for drug infusion, whereby, when the syringe (SR) is engaged in the ferrule (35), the guide member extends over a portion of the length of the hollow body of the syringe (SR).

18. The portable pump according to claim 2, wherein the rod (15) comprises an end portion or pusher (45) provided with an annular portion (45a) radially extending towards the outside of the rod (15) and with a longitudinal portion (45b) axially extending from said annular portion (45a).

19. The portable pump according to claim 3, wherein the rod (15) comprises an end portion or pusher (45) provided with an annular portion (45a) radially extending towards the outside of the rod (15) and with a longitudinal portion (45b) axially extending from said annular portion (45a).

20. The portable pump according to claim 6, wherein said electromechanical unit (13) is supported by a support structure (51) made of metal and comprising a base plate (53) and a frame (55) attached to the plate (53).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Some preferred embodiments of the invention will be described below by way of non-limiting example with reference to the annexed drawings, in which:

[0034] FIGS. 1A and 1B are plan views of a pump according to a preferred embodiment of the invention, with and without electronic board, respectively;

[0035] FIG. 2 is a section taken along a plane A-A of FIG. 1A;

[0036] FIG. 3 is a section taken along a plane B-B of FIG. 2;

[0037] FIG. 4 is a section taken along a plane C-C of FIG. 2;

[0038] FIG. 5 is a side view of the pump of FIG. 1A;

[0039] FIG. 6 is a section taken along a plane D-D of FIG. 2;

[0040] FIG. 7 is a section taken along a plane E-E of FIG. 6;

[0041] FIGS. 8A-8C are perspective views of the electromechanical unit.

[0042] In all the figures, the same reference numerals have been used to indicate same or functionally equivalent elements.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS

[0043] Referring to the annexed figures, the portable pump for drug infusion according to the invention has been indicated as a whole with reference numeral 11.

[0044] The pump 11 made according to a preferred embodiment of the invention mainly comprises an electromechanical unit 13, or drive unit, to cause exit of a drug from a syringe SR removably engaged in the pump 11. The electromechanical unit 13 of the pump 11 has a rod 15 longitudinally slidable within a guide member 17. The rod 15 of the drive unit 13 is capable of exerting an axial thrust onto the plunger SF of the syringe SR engaged in the pump 11.

[0045] Advantageously, according to the invention, in order to prevent the rod 15 from rotating about its longitudinal axis, relative to the guide member 17, during longitudinal sliding, the rod 15 and the guide member 17 both have a non-circular cross-section.

[0046] In the shown embodiment, the cross-sections of the rod 15 and the guide member 17 are complementary to each other and, still referring to the shown embodiment, a minimum clearance is defined between the rod 15 and the guide member 17, such as to allow axial sliding of the rod 15 within the guide member 17, substantially without jamming, but also to prevent oscillations of the rod 15 relative to the guide member 17 during longitudinal advancement of the rod 15.

[0047] Still referring to the illustrated embodiment, the cross-section of the rod 15 and of the guide member 17 is an oval or elliptical cross-section. In other embodiments, other geometrical shapes, preferably comprising at least one curved portion and at least one rectilinear portion, such as, for example, “C”-like or “D”-like shapes may be envisaged.

[0048] The rod 15 is hollow inside and comprises an axial cavity 19, provided with at least one open base 19a. Advantageously, the rod 15 is therefore adapted to receive a screw 21 rotatable about its longitudinal axis and driven by an electric geared motor 23 belonging to said electromechanical unit 13.

[0049] The rotatable screw 21 with its thread 21a is engaged in an internally threaded nut or bushing 27. In the illustrated embodiment, the nut 27 is housed within said cavity 19, at said open base 19a, and is co-molded with or press-fitted in the open base 19a of the longitudinally slidable hollow rod 15.

[0050] Referring in particular to FIGS. 8A-8C, the electromechanical or drive unit 13 further comprises the electric geared motor 23, having a driving shaft 25 provided, in turn, with a pinion 29a engaging with its teeth in a toothed gear wheel 29b fixed to the base of said rotatable screw 21. The electric geared motor 23 is adapted to cause, by means of the coupling between the pinion 29a and the toothed gear wheel 29b, the rotation, preferably in both directions depending on the direction of rotation of the geared motor 23, of the screw 21 and consequent sliding back and forth of the hollow rod 15.

[0051] The pump 11 according to the invention further comprises, in the preferred illustrated embodiment, a casing 31 defining therein a chamber 33 housing the electromechanical unit 13. Still according to the invention, the casing 31 is preferably made of a plastic material, for example by injection molding, and said guide member 17 is molded during forming of said casing 31 and thus forms a single piece with said casing 31. Even more preferably, the casing 31 is entirely made of plastics.

[0052] Still referring to the illustrated embodiment, the casing 31 has a substantially rectangular annular development, which surrounds the chamber 33. In addition, at least one of the opposite bases of the casing 31 is open in order to allow access to the chamber 33 housing the electromechanical unit 13. In the shown embodiment, both the opposite bases of the casing 31 are open. A first base 31a houses a display 32 and a second base 31b houses a printed circuit board 34.

[0053] Still according to a preferred embodiment of the invention, said casing 31 further comprises outside a ferrule 35 capable of receiving, in a configuration of firm engagement, the base SB of a syringe SR for drug infusion. Preferably, said ferrule 35 defines a corresponding bayonet-like coupling for a syringe SR having radially extending and diametrically opposite wings SA. The ferrule 35 includes a pair of opposite arched seats 37a and a pair of diametrically opposite slits 37b, whereby the syringe SR can be engaged into the pump 11 by a coupling movement substantially comprising an axial approaching movement and a subsequent rotation of the syringe SR about its longitudinal axis. In other embodiments, the ferrule 35 may define other types of coupling for the base of a syringe of a different type, for example provided with a screw coupling of complementary coupling provided inside or outside the syringe body.

[0054] In the shown embodiment, as can be better appreciated in FIG. 6, the guide member 17 extends longitudinally outside the casing 31 of the pump 11. In other embodiments, however, it can also be envisaged that the guide member extends inside the casing 31 or both inside and outside said casing 31.

[0055] Preferably, in addition, the guide member 17 comprises an annular gasket 39 housed in an annular cavity or groove 41 and adapted to exert a hydraulic tight-fit action against the outer surface of the slidable rod 15, thus contributing to make the pump substantially waterproof. In the illustrated embodiment, the annular groove 41 is both radially open towards the inside of the cavity 17a of the guide member 17 and longitudinally open outside the guide member 17 and is preferably held in position by a locking cap 43, which is axially fitted on the guide member 17. Advantageously, the locking cap 43 prevents the annular gasket from axially slipping out of said annular cavity 41.

[0056] Still referring to the illustrated embodiment, the guide member 17 is surrounded by said engaging ferrule 35 for the open base SB of a syringe SR for drug infusion, whereby, when the syringe SR is engaged in the ferrule 35 and the guide member 17 is made so as to extend outside the casing 31, the guide member 17 extends over a portion of the length of the hollow body of the syringe SR.

[0057] The longitudinally slidable hollow rod 15 comprises a distal portion 45 or pusher provided with an annular portion 45a extending radially towards the outside of the rod 15, and a longitudinal portion 45b extending axially from said annular portion 45a. Said pusher 45 is apt to be received in a seat SD provided in the sliding plunger SF which causes exit of the drug from the syringe SR through the front end SC.

[0058] The seat SD provided in the plunger SF receives the pusher 45 preferably with some interference, in order to prevent occurrence of the so-called free-flow phenomenon, i.e. the exit of the drug from the syringe SR also in the absence of infusion by the pump 11, because of the difference in hydrostatic pressure due to the position in which the pump 11 may be arranged relative to the patient's body associated with the pump 11 through a dropper or cannula.

[0059] In the illustrated embodiment, the electromechanical unit 13 is supported by a support structure 51 firmly but detachably associated within the casing 31 of the pump 11. The support structure 51 is housed in the chamber 33 in a position distal to said guide member 17.

[0060] Preferably, said support structure 51 is made of metal, for example aluminum, and comprises a base plate 53 and a frame 55 attached to the plate 53 by means of screws 57. Mainly the pinion 29a and the toothed gear wheel 29b are arranged between the base plate 53 and the frame 55. In addition, on the base plate 53, at the center of the toothed gear wheel 29b, there is provided a pressure transducer 59 capable of generating an electric signal proportional to the thrust exerted thereon by a conical tip 61 secured to the base of the screw 21.

[0061] The base plate 53 is preferably substantially flat and rests against a plurality of rest elements 60 extending longitudinally and transversely within the chamber 33 of the casing 31 of the pump 11. The frame 55 is preferably shaped in such a way as to define, between said frame 55 and the plate 53 with which the frame 55 is associated, a chamber 63 suitable for receiving the pinion 29a and the toothed gear wheel 29b. On the frame 55, there are also preferably secured the electric geared motor 23 and the contacts 65, supported by an elastic member consisting, for example, of a helical spring 69, for a battery (not shown) powering said electric geared motor 23. The battery is accessible through a door 67 provided on the adjacent flanks of the casing 31 of the pump 11. Plate and frame preferably form a rigid support structure and are held together for example by screws.

[0062] Still referring in particular to FIGS. 8A-8C, advantageously, according to the invention, the support structure 51 comprises a frame 55 made as a single piece of aluminum and defining said chamber 63 between said frame 55 and said plate 53, the plate 53, too, being preferably made of aluminum. The frame 55 is advantageously shaped in such a way as to define a first chamber portion 63a and a second chamber portion 63b, wherein the distance from the plate 53 is greater for the portion 63a than for the portion 63b. Thanks to this configuration of the frame 55, the support structure 51 mainly comprises only two parts held together by screws 57. The support structure is therefore particularly rigid and lightweight and allows to provide a pinion 29a housed in the chamber portion 63a and having a width greater than the width of the toothed gear wheel 29b housed in the chamber portion 63b, for a better kinematic engagement between said pinion and toothed gear wheel. In the illustrated embodiment, the geared motor 23 is advantageously secured to the frame 55 on the side opposite to the chamber portion 63a. The axis of rotation of the driving shaft 25 is also parallel to the axis of rotation of the screw 21 and the geared motor 23 can be arranged in a position close to the screw 21 and the rod 15. The rod 15, having a non-circular cross-section, is indeed preferably and advantageously oriented in such a manner as to minimize the distance between said rod 15 and the geared motor 23, without any interference between said rod 15 and the geared motor 23 during the entire longitudinal sliding of the rod 15. In the embodiment shown in FIGS. 8A-8C, the rod 15 has a cross-section comprising a substantially rectangular central portion 15a and a pair of rounded peripheral portions 15b. Even more preferably, the transverse axis having a length greater than the cross-section of the rod 15 is perpendicular to a plane passing through the center of the geared motor 23 and through the center of the rod 15. Still referring to this embodiment, the inner cavity 19 of the guide member 15 advantageously and preferably has a complementary cross-section.

[0063] The invention as described and illustrated is susceptible to several variations and modifications, all of which fall within the same inventive principle.