EP-3906072-B1 - PORTABLE PUMP FOR DRUG INFUSION THROUGH A SYRINGE REMOVABLY ENGAGED IN THE PUMP

Inventors

• CANE', Claudio
• CANE', MARIO
• CANE', Paolo

Dates

Publication Date

20260506

Application Date

20191224

Claims (8)

1. Portable pump (11) for drug infusion through a syringe (SR) removably engaged in the pump, said pump comprising a casing defining therein a chamber, a rotationally fixed guide member (17) which extends longitudinally outside, inside or both inside and outside said casing and an electromechanical unit (13) housed within said chamber and having a rod (15) which is longitudinally slidable within said 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) comprises an axial cavity (19) having at least one open base (19a) receiving a rotatable screw (21) actuated by an electric geared motor (23) belonging to said electromechanical unit (13) and having a driving shaft (25) provided with a pinion (29a), which, with its teeth, engages into a toothed gear wheel (29b) fixed to the base of said screw (21), said motor (23) causing, through coupling between the pinion (29a) and the toothed gear wheel (29b), rotation of the screw (21) in both directions, depending on the direction of rotation of the motor (23), and consequent sliding back and forth of the rod (15), said rotatable screw (21) being engaged in an internally threaded nut or bushing (27) housed within said cavity (19) of the rod (15) at said open base (19a), wherein said rod (15) and said guide member (17) have non-circular mutually engaging cross-sections, whereby rotation of the rod (15) relative to the guide member (17) is prevented, characterized in that said non-circular cross-section is an oval or elliptical cross-section.
2. Pump according to claim 1, 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).
3. Pump according to claim 1 or 2, wherein said casing (31) is made of plastic material and wherein said guide member (17) forms a single body with said casing (31).
4. Pump according to claim 3, 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).
5. Pump according to claim 4, 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).
6. Pump according to any of the preceding claims, 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).
7. Pump according to any of the preceding claims, 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).
8. Pump according to any of the claims 3 to 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).

Description

Technical Field The present invention relates to a portable pump for drug infusion through a syringe removably engaged in the pump. The invention falls within the field of electromedical apparatus, intended for the infusion of drugs in liquid form into the body of a living being. More particularly, the invention relates to an electromechanical pump for drug infusion, of the portable type, i.e. which can be "worn" by a patient, for example by means of a suitable case or pouch or the like. Background Art Electromechanical pumps for infusing drugs in liquid form are known in the field of electromedical apparatus. The infusion of the drug takes place through a syringe that is mechanically connected to the pump and hydraulically connected to a living being. The hydraulic connection is usually effected through a cannula and a needle implanted in the body of a living being. An example of a known electromechanical pump for drug infusion is described in EP 2 174 679 A1. The operation of this type of equipment is based on mechanical parts that transform the rotational motion of an electric gear motor into the translational motion of a pusher intended to exert an adequate thrust against the plunger of the syringe connected to the apparatus. The transformation of the motion from rotational to translational is generally carried out by means of a screw/nut coupling. The latter receives the motion from the electric geared motor through a pair of gears. A torque primary gear, or torque drive gear, is fixed to the driving shaft of the electric geared motor, while a secondary gear, or driven gear, is fixed around the nut. A position transducer, or optical encoder, is typically provided to establish the angular position of the driving shaft and transmit it to an electronic controller that governs the operation of the pump and controls the feed rate of the pusher and, consequently, the amount of drug delivered through the syringe in the time unit. Another example of a prior art device is described in WO 02/083209 A1. A drawback of the known electromechanical pumps is determined by the construction complexity of the unit transforming rotational motion of the electric geared motor into translational motion of the pusher. The construction complexity results in high production costs. Moreover, the measures adopted so far to obtain the above-mentioned motion transformation, having to guarantee the optimal operation of the pump for a long time, must comply with high quality standards and are consequently further expensive to implement. A first object of the invention is to solve the prior art drawbacks by providing a portable pump for drug infusion through a syringe removably engaged in the pump which is simple and can be produced in a cost-effective manner. A further drawback of known portable infusion pumps is their excessive weight. As is well known, the main components of the pump that determine its weight are the geared motor, the mechanical parts for the transmission of motion, the casing and the battery that powers the electric geared motor. Since these infusion pumps are especially intended to be worn by an individual, it is clear that the lighter they are, the more they will be appreciated by users. Another object of the present invention is therefore to provide a pump for drug infusion which is lightweight and therefore easily portable. Another drawback of known pumps is the noise caused by the mechanical transmission. As pumps are often worn by individuals in the course of normal activity, noise can be a particularly annoying and undesirable factor and can impair the spread of this type of pump among patients. A further object of the invention is to provide a pump of the above type which is quieter and smoother in the operation of mechanical parts than known electromechanical infusion apparatus. A further object of the invention is to provide a pump that lends itself to being made in a compact and portable format, i.e. that can be easily worn by the user, even in those situations where noise during operation could be annoying. Another object of the invention is to create a portable pump for drug infusion which has a high hydraulic sealing capacity and can therefore be worn by users even in damp environments, such as during normal body care and washing activities. A last but not least object of the invention is to provide a device for drug infusion, which is simple and inexpensive to implement and is therefore suitable for large-scale industrial production. These and other objects are achieved with a portable pump for drug infusion as claimed in the appended claims. Summary of the Invention The portable pump for drug infusion according to the invention mainly comprises an electromechanical unit for causing exit of a drug from a syringe removably engaged in the pump. The electromechanical unit of the pump is provided with a rod longitudinally slidable within a guide member and capable of exerting an axial trust onto the plu