ITBS960061A1 - SYRINGE WITH RETRACTABLE NEEDLE - Google Patents

Description

"SYRINGE WITH RETRACTABLE NEEDLE"

The present invention relates to syringes of the needle type which after use is forced to re-enter the syringe to become inaccessible and inhibit reuse of the syringe itself.

Syringes of the aforementioned type are already known. For example, one of them has been described in a previous Italian patent No. 1248456 by the same inventor and in a corresponding European patent EP No. 0505330.

However, such a known syringe has a laborious and complicated method of initial connection of the needle to the syringe barrel and requires, moreover, the use of a special needle. The needle, in fact, must be equipped with a needle holder that can be inserted and removed from the inside of the syringe cylinder and shaped to lock into the nose of the cylinder itself until it is withdrawn into the syringe, inhibiting its use.

The main object of the present invention is to provide a syringe of the aforementioned type, however, configured to advantageously use a common commercial needle, however and still with the possibility of automatically withdrawing it and concealing it inside the syringe after use.

Another object of the invention is to provide a syringe which by arrangement and combination of elements is simpler, more practical, cheaper and easier to manufacture industrially than known syringes of the same type.

Said objects are achieved with a syringe with retractable needle according to claim 1.

Further details of the invention will in any case become more evident from the following description made with reference to the accompanying indicative and non-limiting drawings, in which:

Fig. 1 shows, in longitudinal section, the syringe assembled and ready for use;

Fig. 2 shows an enlarged part of the syringe in the condition of hooking the needle holder for a subsequent retraction of the needle; And

Fig. 3 shows, still in longitudinal section, the syringe after its use and with the needle retracted.

The syringe proposed here comprises a hollow cylinder 10, a needle holder 11, a needle 12 and a piston 13 with an operating stem 14.

The cylinder 10 has at the rear a gripping flange 10 * and ends at the front with a neck 10 "to which an end cap 15 is applied by pressure. This cap 15 has a central hole in which the needle holder 11 extends and is retained, which it is arranged coaxially to the cylinder 10.

The needle holder 11 has, peripherally, a shoulder 11 'intended to rest against the cap 15 from the inside of the latter. Towards the outside of the cap 15, the needle holder 11 has a nose 11 "on which the needle 12, which may be of the type commonly available on the market, is inserted in the usual way. The central hole of the cap 15 is sized for to allow the needle 12 to pass freely when it is withdrawn into the syringe. The needle holder 11 also has an axial hole 11a, and in said hole, near its end towards the inside of the cylinder, an annular rib is provided. coupling whose function will be evident below.

It should be noted that the needle holder 11 is held inside the cap 15, on the one hand, thanks to the shoulder 11 'and, on the other, by an annular, elastic lip 16, integral with the cylinder 10, extending inside this, obliquely towards the needle holder 11. In particular, the elastic lip 16 has a step 16 'which rests on the peripheral edge of the needle holder with the tendency to push and normally keep the latter resting on the cap through shoulder 11 '. The lip 16 with the relative step 16 'substantially performs the dual function of a mechanical seal and a hydraulic seal, also in the compression phase during the use of the syringe. The step 16 'is however destined to deform and / or the lip 16 to expand, freeing the needle holder when it and the needle have to be withdrawn into the syringe.

The piston 13 slides tightly in the cylinder 10 and is stably constrained, at 13 ', to the rod 14 which extends into the cylinder 10, protruding from the inside beyond the grip flange 10' of the latter.

An axial hole 17 is made in the rod 14 and in the piston 13 in which an extractor element 18 and a recovery spring 19 are mounted. The extractor 18 can slide in said axial hole 17 and move from an advanced position, at the level of the piston. 13, at a rear position, away from the piston. The recovery spring 19 has its opposite ends respectively fixed to the extractor 18 and to a plug 20 applied to the free end, the rear one, of the stem 14.

The ends of the recoil spring 19 are embedded and therefore fixed in the material that constitutes the extractor 18 and the end cap 20. The three components 18,19,20 remain permanently connected and can be manipulated and assembled in place jointly and easily. .

In its advanced position, the extractor 18 is constrained to the stem 14 and keeps the spring 19 taut and loaded.

Due to its constraint in the forward position, the extractor 18 has a peripheral step 18 '- Fig. 2 - which engages with a shoulder collar 17' protruding in the hole 17 of the stem 14 and such as to normally prevent the backward movement of the 'extractor itself.

The extractor also has a semi-mushroom-shaped hooking head 18 ", facing the needle holder 11 and protruding from the piston 13 when the extractor is in the forward position. The hooking head 18" of the extractor 18 is intended for to engage with the needle holder, more precisely to the annular rib 11b in the hole 11a thereof, when the piston is pushed fully into the cylinder. Even when coupled to the annular rib 11b, the coupling head leaves a part of the hole 11a of the needle holder free to delimit - Fig. 2 - a channel Ile for venting the liquid to be expelled to eliminate any back pressure when joining the head 18 "with the annular coast llb, considerable back pressure in the absence of the outlet channel.

The shoulder collar 17 'in the hole 17 of the rod 14 is destined to deform, seep and destroy itself on the step 18' of the extractor 18 when the piston 13 is pushed fully into the cylinder and the extractor 18 is hooked with, and finds support against, the needle holder 11 as well as against the lip 16 in the cylinder. The extractor 18, the spring 19 and the plug 20 are connected together in advance and mounted in the stem 14 with appropriate equipment and so that the extractor 18 is hooked in a forward position to the collar 17 'and the spring 19 is in tension as described, however, in the aforementioned Italian patent.

The syringe is then ready for packaging and its subsequent use as a normal syringe after having applied the needle 12 to the needle holder 11.

However, after the use of the syringe, the needle 12 is withdrawn inside the shaft 14 thus making the syringe useless and the needle inaccessible. When the piston, advancing during the injection, reaches the end of its stroke, the head 18 "of the extractor 18 is hooked to the rib 11b of the needle-holder. Then, by pushing down on the stem, the collar 17 'is deformed by pulling it. of the stem 14 on the step 18 'of the extractor itself, at the same time freeing the needle holder 11 from the stop lip 16,16'. reaction of the preloaded recoil spring 19, dragging with it the needle holder and the needle hooked to it as shown in Fig.3.

Claims (6)

R IV E N D ICA T IO N I 1. Syringe comprising a hollow cylinder (10), a needle holder (11) with a needle (12) connected to it and a piston (13) sliding in the cylinder and constrained to an operating stem (14), where - the rod and the piston have a through axial hole (17) in which there is a sliding extractor (18) connected to a preloaded recovery spring (19); - said extractor (18) can be moved from an advanced position to a backward position and has a coupling head (18 ") which, when the extractor is advanced, protrudes from the piston and is intended to engage the needle holder when the piston is pushed fully into the cylinder; and where - the extractor in the forward position is constrained to it, keeping the spring under tension by at least one coupling means (17 ') which can be folded down when the piston is pushed fully into the cylinder and the extractor head has hooked the needle holder; And - the extractor is moved to the rear position by the recovery spring after the removal of said coupling means, characterized in that said needle holder (11). is applied and detachably retained at a forward end of the hollow cylinder (10), . has a nose (11 ") for coupling with a normal commercial needle (12), . it has a through axial hole in which a collar (11b) is provided, interacting with the coupling head (18 *) of said extractor when this is in its advanced position or the piston is pushed fully into the cylinder, . it is dragged, together with the needle connected to it, inside the stem by the extractor when it is moved to the retracted position by the recoil spring. 2. Syringe according to claim 1, wherein z a> the front end of the cylinder (10) has a neck (10 ") to which a cap (15) is applied having a central hole coaxial with the cylinder, in which needle holder (11) is inserted in said hole and its nose (11 ") protrudes from said cap for appliques the needle, and in which said needle holder is held sially between said cap and a stop lip (16) integral with the hollow cylinder and facing the needle holder. 3. Syringe according to claim 2, wherein said needle holder has a peripheral shoulder (11 ') for resting against the cap from the inside of the latter, and in which said stop lip (16) is elastic and has a step < 161) which rests on the peripheral edge of the needle holder, said step and / or said lip, deforming or expanding to free the needle holder when the piston is pushed fully into the hollow cylinder. 4. Syringe according to claim 3, wherein said lip exerts a mechanical sealing and hydraulic sealing action on the needle holder. 5. Syringe according to any preceding claim, in which the attachment head (18 ") of the extractor is in the form of a semi-mushroom and when attached to the internal collar (11b) of the needle holder defines a channel (11le) for venting the liquid . 6. Syringe with retractable needle, as substantially described above, illustrated and claimed for the specified purposes.