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1. WO2014080417 - SELF-RETRACTABLE SAFETY SYRINGE FOR SINGLE USE

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]
"SELF-RETRACTABLE SAFETY (SRS) SYRINGE FUK SINGLE USE"

TECHNICAL FIELD

The present invention relates to a safety syringe having an auto retractable needle for use in the medical or dental profession or in personal drug administration so that the physicians, surgeons or other needle operators may be protected from the needle-stick injury during its use. The invention, in particular, relates to an assembly of the safety syringe which is simple and easy in handling, in which the hypodermic needle retracts itself automatically by virtue of self generated vacuum and encapsulate within the barrel as soon as the last drop is injected in the body of patient. The syringe thereafter becomes finally locked to become non-reusable. The handling of syringe does not require any special training to the operators. It is simple in manufacture.

BACKGROUND

Generally, syringes are simple axial piston pumps with a plunger that fits tightly in a cylindrical barrel. The plunger can be pulled and pushed along inside the barrel, thereby creating a pressure gradient. Additionally, many syringes carry a sharp and penetrating hollow needle that is intended to puncture the skin, mucous membrane and internal organs of humans or animals for injection or removal of fluids, aerosols, or particulate suspensions.

Recently, there has been noticed growing evidences of needle-stick injuries for, not restricted to medical professionals, children playing in park, a street walkers and the like. Anyone affected by needle-stick injuries may be infected with serious blood born diseases. Further the danger of these injuries may escalate to possible infections from HIV and hepatitis B, even to those medical practitioners who work with these used needles in their normal course of business.

There have been a number of proposals aimed at reducing these needle-stick injuries. Such proposals also include auto-retractable syringes. A number of patents and products have also been introduced in the markets relating to various auto-retractable syringes. In the retractable syringes, when the injection has been administered, the piston is pushed away from the leading end of the barrel by a spring or a similar biasing means and the needle tip is accordingly retracted into the barrel. However these syringes often suffer from the disadvantages i.e. splash occurs back when the needle is caused to be retracted, which makes the injection process complicated and brings inconvenience for doctors and nurses. Conventionally, to

activate the auto-retraction, the plunger of the syringe needs a hard push beyond the normal pressure. Therefore, if the needle of the syringe is drawn from the patient before the auto retraction is activated then it matters little how violent the initial kick-back is. On the other hand, if the auto retraction of the needle in the syringe is activated whilst the needle is in the body of the patient, either accidentally or deliberately, it may be quite uncomfortable or cause undesirable damage to the tissues in which the needle is inserted. There is another kind of syringe in which the needle is retracted into the barrel under the action of spring after injection. However, in such kind of retractable syringes, the needle is retracted too fast which may result in bursting out of blood under the body pressure from the punctured hole on the body, which further brings secondary cross infection. The conventional syringes also lack in full-proof locking arrangement as well as effective retraction mechanism to prevent and restrict further use of syringes once used.

Thus, there is an urgent need for auto retractable single use syringes which may overcome the above mentioned drawbacks and shortcomings to provide a safe, reliable and user friendly auto retractable syringes, which may prevent further use of syringes once used and also can protect against accidental needle-stick injuries.

SUMMARY

An object of the present subject matter is to provide a self-retractable safety syringe.

Another object of the present subject matter is to provide a self- retractable safety syringe for single use.

Another object of the present subject matter is to provide a plunger assembly that includes a plunger barrel and a plunger plug.

Another object of the present subject matter is to provide a plunger assembly that includes plunger plug to be inserted in plunger barrel.

Another object of the present subject matter is to provide the plunger plug with a centrally positioned longitudinally furrowed knob at proximal end.

Another object of the present subject matter is to provide a needle carrier assembly to hold the hypodermic needle.

Another object of the present subject matter is to provide an O-ring to hold the needle carrier inside the outermost barrel and to actuate the retraction mechanism in order to dislodge the needle carrier along with hypodermic needle

Another object of the present subject matter is to complete lock the plunger barrel inside the outermost barrel after usage.

Another object of the present subject matter is to provide the plunger barrel with a piston seal holder structured at the proximal end for holding a piston seal

Another object of the present subject matter is to provide the plunger barrel at proximal end with a pair of diametrically opposite, face to face positioned, parallel finger locks opening at proximal end, bearing outwardly protruded teeth T- 1 , T-3 and inwardly protruded teeth T-2, T-4 to hold the plunger plug firmly inside the outermost plunger barrel and also to release the plunger plug after completion of injection process.

Another object of the present subject matter is to provide the plunger barrel with a pair of diametrically opposite, face to face positioned, parallel finger locks opening at distal end, positioned at the proximal end of the plunger barrel where the two diameters of the plunger barrel perpendicularly bisect each other, to retain the plunger plug inside the outermost plunger barrel and to prevent the removal of plunger barrel from the outermost barrel.

Another object of the present subject matter is to provide a needle carrier hub provided with a pair of outwardly protruded finger locks to centrally as well as axially retain the hypodermic needle.

Another object of the present subject matter is to provide a needle carrier hub provided with outwardly protruded flanges to open the finger locks of the needle carrier hub in order to actuate the retraction mechanism.

Another object of the present subject matter is to provide a needle carrier hub with a spring to retract the hypodermic needle in backward direction when the finger locks of the needle carrier hub open and release the needle due to the movement of elastic O-ring in forward direction to push the flanges of needle carrier assembly.

Another object of the present subject matter is to provide a needle carrier hub an elastic O-ring to retain the needle carrier assembly inside the conical jacket of outermost barrel.

Accordingly, the subject matter described herein generally relates to a safety syringe having an auto retractable needle for use in medical or dental profession or in personal drug administration so that the physicians, surgeons or other needle operators may be protected from needle-stick injuries after its use. Therefore, the invention, in particular, relates to an assembly of the safety syringe which facilitates simple operation and easy handling, in which the hypodermic needle retracts itself automatically by virtue of self generated vacuum and encapsulates within the barrel as soon as the last drop is injected in the body of patient. The syringe thereafter becomes automatically locked to become non-reusable. The handling of syringe does not require any special training to the operators. It is also simple in manufacture.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

Fig. 1 illustrates a line diagram of a plunger barrel and plunger plug of a self-retractable syringe.

Fig. 1(a) illustrates a line diagram of finger locks in plunger barrel of a self-retractable safety syringe.

Fig. 2 illustrates a line diagram of a outermost barrel of a self-retractable safety syringe.

Fig. 3 illustrates a line diagram of needle carrier assembly and its parts of a self-retractable safety syringe.

Fig. 4 illustrates a line diagram of a needle carrier assembly housed inside the conical jacket of outermost barrel of a self-retractable safety syringe.

Fig. 5 illustrates a line diagram of a complete assembly for a self-retractable safety syringe.

Fig. 6 illustrates filling of medicinal dosage in a self-retractable safety syringe.

Fig. 7 illustrates a push of the plunger within the outermost barrel in a self-retractable safety syringe.

Fig. 8 illustrates opening of needle carrier locks in a self-retractable safety syringe.

Fig. 9 illustrates retraction and encapsulation of needle assembly inside the outermost barrel and a complete lock of a plunger barrel in self-retractable safety syringe.

DETAILED DESCRIPTION

The embodiments of the present subject matter are described in detail with reference to the accompanying drawings. However, the present subject matter is not limited to these embodiments which are only provided to explain more clearly the present subject matter to the person ordinarily skilled in the art of the present disclosure. In the accompanying drawings, like reference numerals are used to indicate like components.

The invention is explained with respect to a safety syringe incorporating an auto retractable needle assembly therein. Generally, the safety syringe includes a syringe barrel and a plunger slidably located therein.

The safety syringe 100, according to a preferred embodiment of the present subject matter, is structurally constructed with a plunger barrel 102, a plunger plug 103, a needle carrier 114 and an outermost barrel 108.

The plunger barrel 102, as shown in FIG. 1, is a uniformly elongated hollow cylindrical tubular body provided with a thumb rest 120 at its distal end D and a piston seal holder 132 at the proximal end for holding a piston seal 130, in an embodiment of the present subject matter. The plunger barrel 102 is designed with at least one oppositely positioned, outwardly protruded finger lock 124, opening and directing towards distal end D. The finger lock 124 is designed and shaped by cutting the wall of plunger barrel 102. The finger lock 124 completely locks the plunger barrel 102 inside the outermost barrel 108 by seating conveniently in the inner circumferential conical groove 146 provided at the distal end D of the outermost barrel, after the completion of injection process.

The plunger barrel 102 is designed with the provision of at least one face to face oppositely positioned parallel pair of finger locks (126 and 128) opening and directing towards the proximal end of the plunger barrel 102.

In the embodiment of present subject matter tooth T-l & T-3 of finger locks 126 & 128 respectively are protruded outwardly in normal state. The proximal surface of tooth T-l and T-3 is designed perpendicular to the inner surface of barrel 102, whereas the outwardly distal surface of tooth T-l and T-3 is obliquely inclined to the distal end, finally constituting an oblique notch, which may conveniently seat inside the inner circumferential conical groove 148 provided in outermost barrel 108.

The inner teeth T-2 and T-4 are designed by cutting the inner surface of plunger barrel 102 in obtuse angled shape in such a manner that the teeth T-2 and T-4 remain in the level of inner surface of plunger barrel in normal state, but may seat conveniently into the outer

circumferential groove 138 provided in plunger plug 103, when the teeth T-1 and T-3 are pressed in inward direction to bring them in the level of outer surface of plunger barrel. The thickness of each of the tooth is approximately double than the thickness of the walls of plunger barrel 102.

Besides, an outwardly protruded, diametrically oppositely face to face positioned pair of finger lock 125 and 127 opening and directing to distal end has been provided at the proximal end of the plunger barrel 102. This pair of finger locks 125 and 127 is positioned diametrically opposite to the pair of finger locks 126 and 128 at the angle where two diameters of plunger barrel 102 perpendicularly bisect together, as shown in Fig. 1(a). The outwardly protruded finger locks 125 and 127 prevent the plunger barrel 102 to be completely removed out from the outermost plunger barrel 108 by seating conveniently within the inner circumferential conical groove 146 provided at the distal end of outermost barrel 108.

FIG. 1(b) illustrates the plunger plug 103 in which the outer diameter is equal to the inner diameter of outermost barrel 102 in an embodiment of the present subject matter. The plunger plug 103 is provided with a thickness having uniform circumferential groove 138. The plunger plug 103is centrally designed with a longitudinally furrowed knob 134 at its proximal end. The furrowed knob 134 is positioned parallel to the outermost barrel 102. The furrowed knob 103 is advantageously provided with a lock element 136 at proximal end. The distal portion of this plunger plug 103 is inserted in the outer plunger barrel 102 through its proximal end, positioning the circumferential groove 138 of plunger plug 103 in alignment of inwardly protruded tooth (T-2 and T-4) of the finger locks 126 and 128 as shown in FIG. 5.

The safety syringe 100 also includes a conical needle carrier assembly 114, as shown in FIG. 3(c), comprising a needle carrier hub 112 and a hypodermic needle 110, as further shown in Fig.3(a) and 3(b) respectively.

The needle carrier hub 112 is provided with a longitudinal central axial passage at its centre which is parallel to the plunger barrel 102, in an embodiment of the present subject matter. The axial passage of the needle carrier hub has been provided with three different diameters to hold the hypodermic needle 110 along with spring 184. The inner diameter of axial passage of the needle carrier hub at distal end is equal to the outer surface of the proximal portion of the hypodermic needle seat, whereas the inner diameter of axial passage at proximal end is equal to the outer diameter of hypodermic needle. The different inner diameters in axial passage of the needle carrier hub 112 constitute two collars 174 and 176 between the distal and middle as well as middle and proximal portions respectively.

The needle carrier hub 112 is further provided with two face to face oppositely positioned finger locks 166, opening at distal end and customised , into outwardly extended flanges 168 directing to distal end of the needle carrier hub. The needle carrier hub is also provided with an outer circumferential ridge at its proximal end to fixedly hold the needle carrier assembly 114 in outermost barrel by seating conveniently in the inner conical groove 150 provided at the proximal end of the outermost barrel.

The straight, hollow elongated hypodermic needle 110 has been provided with a needle seat at the distal end. The distal end of the needle seat is customised into a collar 154 having its width and outer diameter respectively equal to the thickness and inner diameter of the elastic O-ring 182. The proximal portion of needle seat is provided with a uniform circumferential conical groove 156, whose proximal end is perpendicular to the outer surface of needle seat, whereas at distal end the groove 156 is inclined to the distal end to constitute a convenient seat for the teeth of finger lock 170 provided at the inner surface of finger lock. The hypodermic needle is provided with a radial cavity 160 around the needle to hold the spring 184.

The axial passage of hollow hypodermic needle 151 opens at both ends, which is modified into a cavity at the distal end having a lock element 152. The inner diameter of the cavity 151 is equal to the outer diameter of the knob 134 which is centrally provided at the proximal surface of the plunger plug 103. The hollow needle 151 is advantageously encapsulated in a removable needle cover 154.

The conical needle carrier hub 1 14 is also structured with an elastic O-ring 182 having inner diameter and thickness equal to the outer diameter and thickness of distal portion of conical needle carrier 114. The outer diameter of O-ring 182 is equal to the slightly enlarged inner proximal diameter of the outer barrel 108, wherein the outer proximal circumferential edge of O-ring 182 is round in shape.

When the proximal end of hypodermic needle 110 along with spring 180 is inserted into the needle carrier hub 112 through its distal end, the finger lock 166 is expanded in outward direction and the conical notch 170 clicks lock the hypodermic needle inside the needle carrier hub 111, by conveniently seating into the outer circumferential conical groove 156. The compressed spring 184 is held encapsulated within the radial cavity 180. The elastic O-ring 182 is fitted around the distal collar 154 of the needle carrier hub 112 keeping rounded outer edge surface of O-ring 182 in proximal side in such a manner that the proximal surface of the O-ring rests at the distal surface of the flange 168 of the finger lock 166 to constitute complete needle carrier assembly 114, as shown in Fig. 3(c).

FIG. 2 shows the outermost barrel 108 which is a uniformly elongated hollow cylindrical tubular body, provided with a finger rest 140, a uniform obtuse-angled L-shaped inner circumferential conical groove 146 at the distal end and another inner circumferential conical groove 150 at the proximal end of the barrel 108 in an embodiment of the present subject matter. The barrel 108 is customised into a conical jacket opening at the proximal end to hold the needle carrier assembly 114 along with hypodermic needle 110.

The inner diameter of the outermost barrel 108 is equal to the outer diameter of the plunger barrel 102, which slightly enlarges at the proximal portion of the barrel constituting a collar 144 to fixedly retain the needle carrier assembly with the help of elastic O-ring 182. An inner circumferential conical groove 148 is provided before the distal end of the collar 144 formed between the two inner diameters inside the outermost barrel 108 to allow the expansion of finger lock 126 and 128 in outward direction so that the plunger plug 103 may be set free to release freely.

The conical groove 146 is inclined obliquely to the proximal end of the barrel 108 to facilitate sliding of an elastic O-ring 182 and snap-lock the plunger assembly 114 inside the outermost barrel 108 after the finger lock 124 becomes in normal state with the completion of the injection in an embodiment of the present subject matter.

When the proximal end of the needle carrier assembly 114 holding hypodermic needle 110 and the O-ring 182 is inserted into the outermost barrel 108, through distal end, the rounded outer edge of O-ring easily crosses over the inner circumferential grooves 146 and 148 of the outermost barrel 108 and conveniently seats within the slightly enlarged proximal portion of the outermost barrel constituting conical jacket 142. The circumferential conical ridge 172 provided at the proximal surface of the needle carrier hub 112 clicks lock to securely fix the needle carrier assembly 114 within the conical jacket and the needle protrudes out through the opening at proximal end of the conical jacket. The needle is securely encapsulated in a needle cover.

The distal portion of this plunger plug 103 is inserted in the outer plunger barrel 102 through its proximal end, positioning the circumferential groove 138 of plunger plug 103 in alignment of inwardly protruded tooth (T-2 and T-4) of the finger locks 126 and 128 as shown in FIG. 5.

The proximal end of the plunger barrel 102 containing the plunger plug 103 is now inserted into the outermost barrel 108 through its distal end. On exerting pressure on the plunger barrel in forward direction with the help of thumb rest 120 and the finger rest 140, the outwardly protruded teeth T-1 and T-3 are pressed in inward direction to become in level of the outer surface of the plunger barrel 102, consequently, the inwardly protruded teeth T-2 and T-4, which are in the level of inner surface of the plunger barrel in normal state, are pressed and protrude inwardly to seat conveniently inside the outer circumferential groove 138 and secure hold the plunger plug 103 firmly at the proximal end of the plunger barrel 103, to constitute the complete syringe assembly 100, as shown in Fig. 5.

While working with the syringe, the user has only option to pull out the inner plunger barrel 102 by holding the safety syringe 100 with the help of the thumb rest 122 and the finger rest 140, because the outwardly protruded finger locks 125 and 127 at the proximal end of the plunger barrel 102 prevent the plunger barrel to be completely removed from the outermost barrel by expanding in outward direction and seating conveniently inside the inner circumferential groove 146.

The medicinal dosage to inject into the body of the patient may be sucked into the outermost barrel 108 by pulling the plunger assembly 102 in backward direction as usual, as shown in another embodiment of FIG. 6. While injecting the medicinal dose with the safety syringe 100 into the body of patient according to the present subject matter, in final stage, the proximal end of barrel 102 pushes the O-ring 182 in forward direction to dislodge the needle carrier 114, when injection process is likely to complete. The forward movement of plunger assembly 102 makes the furrowed knob 134 of the plunger plug 103 to insert inside the cavity 151 of the needle carrier 114 and gets snap-locked therein the cavity 151 as soon as the last drop of medicine is injected in the body of patient.

The movement of O-ring 1 82 in forward direction pushes the flange 168 of finger lock 166 of the needle carrier hub 112 in forward direction, which results in the opening of finger lock to release the hypodermic needle 110. Consequently, the compressed spring 184 expands in backward direction to facilitate retraction of needle 110 in backward direction. The needle 110 along with the plunger plug 103 is dislodged from the needle carrier hub, which gently as well as smoothly slides in backward direction into the plunger barrel 102. Simultaneously, the finger lock 124 provided at the distal end of the plunger slips into the inner circumferential conical groove 146 of the outermost barrel, which expands in outward direction into the space provided by the groove 146 to restore its normal state and seats therein conveniently to completely lock the plunger barrel inside the outermost barrel, as shown in Fig. 9.

In this way, the needle of syringe 100 retracts and encapsulates inside the plunger barrel and the syringe becomes completely locked to render itself completely useless for any further use.