Dirk, Diepbrink
Hendrik
De Kler, Dirk Diepbrink Hendrik
| 1. | Hypodermic syringe having a cylinder on an end portion whereof a hypodermic needle is releasably arranged, a piston displaceable in the cylinder and a coupling means connected to the piston and coacting with the hypodermic needle system for connecting the piston and the hypodermic needle system in the end position of the piston oriented towards the needle, characterized in that the hypodermic needle system has a hub engaging close fittingly over the end portion of the cylinder and a connecting element con nected fixedly to the needle and received releasably inside the hub, and the coupling means are formed by flexible legs gripping the connecting element. |
| 2. | Hypodermic syringe as claimed in claim 1, charac¬ terized in that the connecting element has a peripheral edge for coaction with the legs on the coupling element. |
| 3. | Hypodermic syringe as claimed in claims 12, characterized in that the hub has a longitudinally oriented bore in which the connecting element is close fittingly received. |
| 4. | Hypodermic needle system for use with the hypo¬ dermic syringe as claimed in claims 13, characterized by a hub, in a longitudinal bore of which a connecting element is closefittingly received, and a needle connected fixedly to the connecting element. |
| 5. | Hypodermic syringe having a cylinder on an end portion whereof a hypodermic needle is releasably arranged, a piston of borable material displaceable in the cylinder and coupling means connected to the piston and coacting with the needle for connecting the piston and the needle in the end position of the piston oriented towards the needle, characterized in that the coupling means are formed by flexible legs and that the needle has notches. |
| 6. | Hypodermic syringe as claimed in claim 5, charac¬ terized in that the flexible legs form part of a coneshaped member open at the top. |
| 7. | Hypodermic syringe as claimed in claim 6, charac terized in that the flexible legs have cornerlike end portions. |
| 8. | Hypodermic syringe as claimed in claim 5, charac¬ terized in that a number of flexible parts are arranged distributed regularly over the periphery. |
| 9. | Hypodermic syringe as claimed in claim 5, charac¬ terized in that the needle is flattened at the location of the notches. |
| 10. | Hypodermic syringe as claimed in claim 5, charac¬ terized in that the notches take the form of cutout por tions. |
| 11. | Hypodermic syringe as claimed in claim 5, charac¬ terized in that a stop is arranged on the needle. |
| 12. | Hypodermic syringe as claimed in claims 511, characterized in that the flexible legs are connected to a base member placed transversely of the legs. |
| 13. | Hypodermic syringe as claimed in claim 12, cha¬ racterized in that the base member can be moved in form fitting manner into a groove arranged in the piston and can be locked therein by means of a ball catch connection. *****. |
The invention relates to a hypodermic syringe having a cylinder on an end portion whereof a hypodermic needle is releasably arranged, a piston displaceable in the cylinder and a coupling means connected to the piston and co-acting with the hypodermic needle system for connecting the piston and the hypodermic needle system in the end position of the piston oriented towards the needle. Such a hypodermic syrin¬ ge is known from the American patent specification 4950241 In a known hypodermic syringe a connecting piece is placed in the hypodermic syringe. A needle with hub is pushed onto this connecting piece in the usual manner. The channel of the needle connects therein onto the bore ar¬ ranged in the connecting piece. After injecting, the piston is coupled by means of a coupling member to the connecting piece and when the piston is retracted the connecting piece and the needle and hub placed thereon are pulled inside.
It is the object of the invention to provide a hypo¬ dermic syringe consisting of a limited number of components which can be assembled simply and inexpensively to form the end product. It is a further object of the invention that the components used are manufactured by an injection moul¬ ding production process.
This is achieved according to the invention in that the hypodermic needle system has a hub engaging close fit- tingly over the end portion of the cylinder and a connecting element connected fixedly to the needle and received relea¬ sably inside the hub, and the coupling means are formed by flexible legs gripping the connecting element.
The number of components of both hypodermic syringes according to the invention remains limited. After injecting, a coupling is effected between the piston and the connecting element by means of flexible legs. During coupling care must be taken that an outward directed movement does not occur, which would result in the needle penetrating further into the patient.
This is achieved in that the hub engages close-fit¬ tingly on the cylinder so that the clamping force is greater than the force exerted on the connecting element during coupling. Displacement of the hub, the connecting element and the needle is thereby avoided.
According to another embodiment the coupling means are formed by corner-like portions arranged on flexible legs and the needle has notches.
Further advantages and features will become apparent from the following description of an embodiment. In the drawings:
Fig. 1 shows a perspective view of the hypodermic syringe according to the invention;
Fig. 2 is a perspective view of a detail of the coupling mechanism;
Fig. 3 is a view similar to fig. 1 in a different position of the hypodermic needle;
Fig. 4 is a view similar to fig. 2 in a different position of the needle; Fig. 5 is a cross-sectional view along the line V-V in fig. 4; fig. 6 shows an alternative embodiment of the needle and the manner of fixing of the legs on the piston; fig. 7 shows an embodiment wherein the legs form part of a conical wall; and fig. 8 is a view similar to fig. 7 in a different position of the needle.
Fig. 9-16 show a second embodiment of the invention. The hypodermic syringe comprises a cylinder casing 1 wherein the piston 2 is slidably arranged. Placed on the end of the casing 1 is a fitting piece 3 which receives the needle 5 with interpositioning of a filler material 4. In typical manner the needle is provided on its extremity with a sharpened penetrating end 6 in order to be able to insert the needle in the human body. The liquid 7 for injection is arranged in the cylinder space between the piston and the end of the cylinder casing located by the fitting piece 3. After the liquid 7 has been injected, the needle is carried
along, as a result of a coupling between an end portion 8 of the piston and the needle 5, inside the cylinder space when the piston is retracted in the direction of the arrow in fig. 3, so that accidental pricking does not occur. The coupling mechanism according to the invention for effecting a connection between the needle 5 and the end por¬ tion 8 of the piston consists of a notch 9 arranged in the needle and flexible legs 11 on the piston 2.
The legs 11 can form part of the flexible wall of a cone-shaped member (see fig. 7 and 8) or be separate legs 11 with bent corner-like portions 10 separated by a lengthwise slit, for instance the slit 20, as in the embodiment accor¬ ding to fig. 1 and 2. A number of such legs with bent cor¬ ner-like portions are arranged distributed over the periphe- ry ( ig. 5) . When the legs reach the end portion 12 of the needle 5 closest to the piston 2, they bend radially outward because they are of flexible material and, when they reach the notch 9, they snap in behind the edge 13, thus effecting an operationally reliable coupling between the piston 2 and the needle 5.
The needle 5 is in addition provided with an outward curving lip 14. The lip 14 engages behind the transverse wall 15 of the fitting piece 3 in order to avoid the needle 5 being carried too far into the body during coupling of needle and piston.
In the embodiment according to fig. 6 the needle is flattened on its end portion 16 and provided with notches 17 running transversely on the flattened portion. The legs 18, 19 leave free passage room for the flattened portion 16 and lock behind the notches 17. The legs form an entity with the base member 20 which is oriented transversely of the legs 18, 19. The base member 20 can co-act in form-fitting manner with a groove 21 arranged in the piston and can be locked to the piston by means of the ball catch connection. This construction also enables use of the hypodermic syringe according to the invention without the coupling means according to the invention, so that universal use becomes possible.
In the embodiment according to fig. 10-16 use is made of a construction wherein the suction needle according to fig. 10 consists of a hub 30 in which the needle 31 is fixed. A protective cap 32 is placed in the usual manner onto the hub 30.
The hypodermic needle according to fig. 11 likewise has a hub 33 corresponding with the hub 30. Pushed onto the hub is a cap 34 similar to the protective cap 32. The hypo¬ dermic needle 35 is fixed by means of adhesive in a bore in a connecting element 36 of plastic. Use can be made here of a connecting element with a diameter of the bore such that needles of different diameters can be placed therein. Any clearance between the bore and the needle can be bridged by using a greater quantity of adhesive. The hub 33 fits close-fittingly round the upper portion 37 of the connecting element 36.
The suction needle according to fig. 10 and the hypodermic needle of fig. 11 are used with a hypodermic syringe according to fig. 9. As is typical, the hypodermic needle according to fig. 9 comprises a cylindrical part 38 in which is received a movable piston 39. The piston 9 has outward oriented, hook-like flexible legs 40, 41. In the situation of fig. 9 the suction needle according to fig. 10 is placed on the hypodermic syringe by sliding the hub onto the end portion 42 of the hypodermic syringe (see fig. 12) . After removing the protective cap 32 the suction needle 31 can be placed in a liquid and injection liquid can be drawn up by retracting the piston. After removing the suction needle, the hypodermic needle according to fig. 11 is placed on the hypodermic syringe (fig. 14) . After removal of the protective cap 34 the needle is placed in the patient and the injection liquid introduced by displacing the piston (fig. 15) . In the end position of the piston the legs 40, 41 engage behind the peripheral edge 44 owing to the flexible character of the legs. During this movement an outward oriented force is exerted on the hypodermic needle. In order to avoid the
hypodermic needle penetrating further into the body of the patient during this movement, the friction between the hub 33 and the connecting element 36 relative to the end portion 42 of the hypodermic syringe is selected such that the coupling force between the connecting element 36 and the legs 40, 41 is smaller than the friction force between the said parts. The connecting element 36 is blocked in relation to the hub 33 by the collar arranged on the connecting element 36. When the piston is retracted (fig. 16) the piston 39 carries the connecting element and the needle 35 fixedly connected thereto with it inside the cylinder 38 of the hypodermic syringe. The danger of accidental pricking is thus avoided.
Next Patent: SAFETY SYRINGE WITH RETRACTABLE NEEDLE