GB2202748A

GB2202748A - Syringe with retractable protection for the needle

Info

Publication number: GB2202748A
Application number: GB08802505A
Authority: GB
Inventors: Michele Minischetti
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-02-13
Filing date: 1988-02-04
Publication date: 1988-10-05
Also published as: FR2610829A3; GB8802505D0; DE8801853U1

Abstract

The syringe comprises a sleeve 7, longer than the injection needle 5, concentrically fitted onto the syringe body 1 via a peg-in-groove system (8,9 Fig. 1), which allows it to slide between a retracted position which permits the needle 5 to be used in a conventional manner, and an extended or protection position, in which the sleeve 7 encompasses the needle 5 so as to prevent accidental contact with its tip. <IMAGE>

Description

"SYRINGE FOR MEDICAL AND DENTAL USE WITH A RETRACTABLE PROTECTION FOR THE INJECTION NEEDLE" DESCRIPTION Background of the invention 1. Field of the invention The present invention relates to medical equipment, and more particularly to a syringe for medical and dental use with a retractable protection of the injection needle.

2. Description of the prior art As is known to those skilled in the art, disposable syringes are nowadays to be considered of almost generalized use in consideration of the undoubted advantages from the hygienical and practical point of view. Also in the dental practice the means for gum injections have been subjected to significant improvements.

From the technical operative point of view, considerable results have been obtained. However the same is not true for the necessary and indispensable guarantees of sterility for all the above apparatuses as far as all the operative steps are taken into account. An injection needle after use represents a dangerous carrier of infectious disease. In fact an accidental puncture by such a needle can cause an infection to be transmitted, such infection being Liable to assume particular seriousness, as in the case AIDS, viral hepatitis and so on.

At the present, a cap is provided in order to protect the injection needle, but such a cap, after being removed before the use of the needle, is not replaced again, or in the case when it is replaced onto the needle after use, it can cause accidental punctures on the operator's fingers, since it has to be replaced starting from the tip of the needle. Moreover, taking into account that some injections, especially in the dental practice, have to be done in two steps spaced with each other, such a danger of accidental punctures greatly increases. Also in the subsequent steps of cleaning the outpatients department, laying out and setting the apparatuses, collecting, transferring and discharging the waste and so on, there are a number of possibilities for accidental punctures with a subsequent danger of infection.

Even more serious is the danger of the non-returnable syringes normally used by the families, which -are thrown into the urban solid waste, since they represent a risk not only for the members of a family, but also for those who transport and remove the wastes. For example, the used syringes can cause a hole in the plastic sack which is usually employed for collecting wastes during transfer to the collecting box.

Summary of the invention The object of the present invention is to overcome the above drawbacks by means of a protection unit simple, practical, cheap, which has not to be inserted starting from the tip of the needle.

According to the invention, a syringe is provided comprising a sleeve having a length longer than that of the needle, in telescopic engagement onto the syringe cylinder and provided with means allowing it to slide between two positions, i.e. a retracted position which permits the injection needle to be used (after removing the conventional protection cap) and an extended position, or protection position, in which said sleeve encompasses the needle in such a way that any accidental contact with the tip of the needle can be avoided.

More precisely the subject matter of the present invention is a syringe for medical, particularly dental use of disposable type including a piston, a cylinder and a needle, comprising: a sleeve in telescopic relationship to said cylinder; engagement means on said cylinder and said sleeve including a pin and a slot in slidable engagement, said slot including a longitudinally extending stroke portion and circumferentially extending retaining portions at the end of the stroke portion, said sleeve having a longitudinal extent such that it is capable of assuming on said cylinder a retracted position wherein said needle is exposed, and an extended position wherein said needle is completely protected within said sleeve, and said sleeve is retained in said retracted and extended portions by engagement of said pin in said retaining portions of the slot.

Description of the drawings \ The invention will now be described by reference to the accompanying drawings which show preferred embodiments of the invention. Such embodiments are only given by way of example and in -no way can be constructed to limit the scope of the appended claims.

In the drawings: - figure 1 is a longitudinal section, on an enlarged scale, of a syringe according to the invention, showing the sleeve in the retracted position; - figure 2 is a section similar to that of figure 1, showing the sleeve in the protection position; - figure 3 shows particulars of the slide and stop means of the protection sleeve; and figure 4 represents another embodiment of the units sliding on each other.

Description of the preferred embodiment With reference to figure 1, in 1 the body of a syringe is indicated, for instance a disposable syringe, provided with a chamber 2 in which the medicine to be injected is sucked up by means of the piston 3. In the case of syringes for dental use, the chamber 2 is aimed to receive an ampulla (not shown in the figure) with a piston incorporated thereto, which is driven by a stem connected with a handle. These parts are not described, since they are known.

The injection needle 5, which is protected by a removable cap 6, is sited in the front portion of the syringe 1, by means of a joint 4. The invention provides a protective sleeve 7, in telescopic engagement with cylinder 1 of the syringe and cap-able of sliding, when desired, between two positions, and namely a retracted position, shown in full line, in which the needle 5 is protected by the cap 6, and an extended position, shown in dotted line, in which the sleeve 7 encompasses the needle (protection position). The stroke between the above two positions takes place by means of a pin 8 which runs in a slot 9 (figure 3) provided with two end portions 10 and II, of a bayonet type, which permit the protection sleeve 7 to be blocked, when desired, in one of the above two positions.In figure 3, the slot 9 has a straight stroke portion directed parallel to the longitudinal axis of the cylinder 1 and two pin retaining portions 10 and 11 perpendicular to the straight portion.

In figure 4, the sliding of the sleeve 7 is obtained by means of a pin 12 on the cylinder 1, over which a corresponding helical slot 13 in the sleeve 7 can slide.

In this embodiment also, two circumferentially directed retaining portions (not shown) are preferably provided at the ends of the helical slot 13.

The use of the syringe according to the invention is very simple. Starting from the position of figure 1 (use position), the protective cap is extracted and the injection takes place, then the external sleeve 7 is driven forward to reach the position shown in figure 2. Under these conditions, it is evident that the needle, now deprived of the cap 6, results protected and it is impossible to prick ones finger with it, since in turn it is impossible to introduce a finger into the sleeve 7 owing to its small diameter (as already said, in the drawings such a diameter is enlarged for reasons of clarity).

It is evident that, in the case where the injection has to be carried out in two steps, it is sufficient to put the sleeve in protection position during the relevant period, after which it can be retracted again in order to accomplish the final step of injection. After this operation, the sleeve 7 is once and for all brought into the protection position. It has to be appreciated that, while in the drawings embodiments are shown, in which the slot is provided on the sleeve and the pin is integral with the cylinder, the arrangement of pin and slot can be inverted, so providing the slot in the cylinder and the pin on the sleeve.

Moreover the term "slot" is used also as including a groove structure. In fact, while a slot in the sleeve can be an "open" slot, a slot in the cylinder can only be configured as a groove on the cylinder wall.

As is evident from the foregoing, the invention can be applied either to syringes for general use, for instance intramuscular or intravenous use, or for dental use, with or without an articulated joint.

The present invention has been described and illustrated with reference to preferred embodiments thereof.

However, it is clear that structural modifications can be made thereto without going outside the scope of the appended claims.

Claims

1. A syringe for medical, particularly dental use of disposable type including a piston, a cylinder and a needle, comprising: a sleeve in telescopic relationship to said cylinder; engagement means on said cylinder and said sleeve including a pin and a slot in slidable engagement, said slot including a longitudinally extending stroke portion and circumferentially extending retaining portions at the end of the stroke portion, said sleeve having a longitudinal extent such that it is capable of assuming on said cylinder a retracted position wherein said needle is exposed, and an extended position wherein said needle is completely protected within said sleeve, and said sleeve is retained in said retracted and extended portions by engagement of said pin in said retaining portions of the slot.

2. A syringe according to claim 1, wherein said stroke position of the slot is a straight length in a direction parallel to the longitudinal axis of said cylinder and said retaining portions are perpendicular thereto.

3. A syringe according to claim 1, wherein said stroke portion of the slot is an helical length coaxial to the axis of the cylinder.

4. A syringe according to claims 2 or 3, wherein said pin is integral with said cylinder and said slot is provided in said sleeve.

5. A syringe according to claims 2 or 3, wherein said pin is integral with said sleeve and said slot is a groove in said cylinder.