WO1999022792A1

WO1999022792A1 - Self-injection device

Info

Publication number: WO1999022792A1
Application number: PCT/IT1997/000273
Authority: WO
Inventors: Ermanno Greco
Original assignee: Ermanno Greco
Priority date: 1997-11-03
Filing date: 1997-11-03
Publication date: 1999-05-14
Also published as: AU4883797A

Abstract

The present invention concerns a mechanism for allowing self-injection with a mechanical injector consisting of a syringe with a disposable needle, in conditions of safety, by preventing the accidental separation of the needle and the consequent expulsion of the needle from the injector.

Description

DESCRIPTION

SELF-INJECTION DEVICE

Technical Field

The present invention concerns a mechanism for allowing self-injection with a mechanical injector consisting of a syringe with a disposable needle, in

conditions of safety, by preventing the accidental separation of the needle and

the conseguent expulsion of the needle from the injector.

Background Art

Self-injection devices are widespread and have been used for a long time now

in the treatment of various pathologies, with satisfactory results.

Said devices are generally cylinder-shaped and resemble a pen. inside which

there is a piston activated by a spring which, when it is released by the patient, strikes the syringe plunger and makes the injection.

This device however, may feature shortcomings, due to the separation of the needle during the injection, which is the cause of obvious discomfort.

Disclosure of Invention

According to the present invention, the syringe inside the device is housed

within an elastic sliding bush which moves forward together with the syringe

during the injectioin: the lower end of the elastic bush container is tapered.

which prevents the needle from separating from the device at the end of the stroke, during the injection. The situation whereby the needle accidentally projects from the syringe may

occur because the end section of the bush must be elastic and capable of being

widened to extract the needle-cap, therefore, when the piston strikes the

syringe plunger, the needle might go beyond the elastic barrier represented by

the bush and be expulsed.

To prevent this from occuring, the container inside which the bush slides is

tapered at the lower end, as mentioned above, and this prevents the elastic end

of the bush to widen when it reaches the end of the stroke, i.e. at the injection.

Brief Description of the Drawings A specific embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows a partially exploded view and a cross-section of the lower and upper ends of the device;

Fig. 2 shows a partial cross-section of the device when the needle-cap is removed;

Fig. 3 shows a partial cross-section of the device at the injection;

Fig. 4 shows the lower end of the device after the injection, during the

reloading operation.

Referring to the drawings, the device described herein features a tapered section 11 at the lower end of the cylinder 5, which prevents the end section 12 of the elastic bush 4 from expanding when, due to the effect of the

injection, the bush 4 reaches the end of die stroke; in the situation shown in fig. 3. the end section 12 of the bush 4 are forced to remain in the resting position, thus preventing the accidental projection and separation of the needle

2 of the syringe 1. As previously mentioned, the accompanying drawings

show the various stages of operation of the device, before, during and after the

self-injection.

In Fig. 1, the syringe 1, ready for use, is inserted into the lower end the self-

injector, while the elastic bush is blocked by the button 7; the syringe is

pushed into the bush 4 until the flixible section 12 of the bush clicks into place. The flexible end 12 of the bush 4, by opening outwards, enables the passing of the needle protection 3 and, after this, it adheres to the plastic part of the

needle 2, positioning itself between the collar 2 and the protection 3.

In fig. 3, the device is shown with the top part of the self- injector screwed into

place, while the needle protection 3 is removed by pulling it downward.

Fig. 3 shows how, by activating the triggering mechanism in the top part of the self- injector, the syringe 1 and the bush 4 slide down until the end of stroke, represented by the gasket 10; the tapered section 11 of the cylinder 5 prevents the elastic section of the bush 4 from opening at the end of stroke 10

and, therefore, keep the needle firmly attached to the syringe. Fig. 4 shows how, at the end of the injection, the protection 3 is placed over the needle and the top part of the injector removed; the return spring 8 causes

the syringe to return into the lower part of the cylinder 5, thus freeing the

elastic section of the bush and enabling the extraction of the syringe with the needle protection. The preferred embodiment described and illustrated above may be modified in accordance with the state of the art, but in compliance with the following claims.

Claims

- A safety system for the disposable needles used for self-injection devices

characterised by the fact that the bush 4, furnished with clastic terminals 12

and a hook 13; characterized by a specific form, permits insertion and

removal after use of the syringe with the removable needle together with its

protective cap. - Safety sistem for removable needles used in autoinjection devices characterized by the fact that, with the syringe inserted, the hook 13 of the elastic terminals 12, locates between the needle's protective edge 3 and the plastic edge of the needle 2 itself.

- Safety sistem for removable needles used in autoinjection devices

characterized by the fact that, with the syringe inserted in the bush 4, at the

moment of screwing the upper part 14 to the lower 5, the elastic terminals 12 of the bush 4 position themselves in the restriction 11 of the cylinder 5, already preventing the elastic terminals 12 expanding outwards, in such a way that the removable needle is prevented from detaching from the syringe.

- Safety sistem for removable needles used in autoinjection devices characterized by the fact that during injection the terminals 12 remain

positioned in the restriction of the cylinder 5 preventing detachment of the

needle consequent upon impact of the bush 4 with the end stop 10.