GB2278060A

GB2278060A - Splittable needle

Info

Publication number: GB2278060A
Application number: GB9409369A
Authority: GB
Inventors: Raymund Heiliger; Matthas Wilhelm Jansen; Bernd Gottfried Roosenboom
Original assignee: Vygon GmbH and Co KG
Current assignee: Vygon GmbH and Co KG
Priority date: 1993-05-19
Filing date: 1994-05-11
Publication date: 1994-11-23
Anticipated expiration: 2014-05-11
Also published as: ITMI940970A1; FR2705239A1; ITMI940970A0; IT1269774B; GB2278060B; DE4316793C1; GB9409369D0; FR2705239B1

Description

2278060 SPLITTABLE NEEDLES The invention concerns a needle splittable into

two longitudinal halves, the proximal end of which needle is fitted with a sleeve which is also splittable into two longitudinal halves. The sleeve has axially aligned notches on opposite longitudinal sides. on each sleeve half thus defined, which encloses a pre-split end piece of the needle, is formed a radially projecting fin.

Such needles as generally known are used for example in paediatrics as constituent elements of a catheter range f or parenteral f eeding and long-term treatment with drugs to be administered intravenously. The splittable needle, preferably f itted with a ground f acet on its tip, serves to create a secure peripheral vascular access by the introduction of a catheter through the lumen of the needle. After the insertion of the catheter, for example made of a heat-sensitive polyurethane, into the vein, the needle has fulfilled its access and guidance function and must be removed. Removal however cannot be achieved by withdrawing the needle coaxially over the proximal end of the catheter as, to connect the catheter to a supply line, a coupling piece is permanently attached at the relevant catheter end which consequently prevents coaxial needle withdrawal. For this reason, the needle is equipped with notches on opposite longitudinal sides which extend over the entire needle 2 - length and which allow the needle to be split into two longitudinal halves.

The radially projecting f ins which are formed on the sleeve 5 fitted to the proximal end of the needle are used to facilitate the splitting process. As the sleeve is also equipped with axially aligned notches on opposite sides in the same way as the needle, the splitting process can be instigated by a swivel movement of the fins.

The known splittable needles have the following important disadvantage:

A swivel movement of the fins formed on the sleeve towards each other around the central axis of the needle places under tension only the sleeve half facing away from the fins which, supported by the corresponding notch in this sleeve half, leads to its breakage. In contrast, the swivel movement of the fins merely compresses the sleeve half facing towards these, which leads to a compression of the sleeve half concerned such that a complete split of the sleeve cannot be achieved solely by a swivel movement of the fins towards each other. In the design f orms known it is therefore necessary, after a swivel movement of the fins towards each other, to carry out a f urther swivel movement of the f ins away from each other. The necessary double swivel movement has the particular disadvantage that only the f irst, in which the f ins are moved towards each other, can be carried out with two fingers on one hand, in contrast to which the second, in which the f ins must be moved away from each other, requires two f ingers on each hand in order to hold the fins securely during the spreading process.

The task of the invention is therefore to form a needle of the type described initially such that at least the sleeve, which is fixed relatively to the needle shaft, can be split completely with only two fingers on one hand by a single swivel movement of the fins formed on the sleeve.

To solve this task, a needle of the type described in the preamble of the patent claim 1 is used, which according to the invention has the features specified in the characteristic part.

Because of the projection according to the invention, only one swivel movement of the fins towards each other is required to split the sleeve completely. During the first part of the swivel movement, the sleeve half facing away f rom the f in is split in the known manner. When this is completed, the projection of one fin according to the invention comes to rest against the other fin. The swivel axis of the fin is consequently forced to move from the central axis of the needle to the rest position. This means that on continuation of the fin swivel movement, the sleeve half facing the fins is placed under tension and is split in - 4 the same way as the sleeve half f acing away from the f ins which has already been split.

With a single swivel movement of the fins carried out by two f ingers on one hand, the two sleeve halves can be split in succession and without increased use of force.

In a particularly advantageous design of the invention, a projection is formed on both fins on their sides facing each other, arranged such that after a swivel movement of the fins towards each other which splits the sleeve open, the projections come to rest against each other and by a continued swivel movement of the fins around the rest point, the sleeve can be split completely.

The mirror-image symmetrical design of the two f ins each with one projection allows for the mirror-image symmetrical design of the two sleeve halves, and thus promotes a flowing severance movement during the splitting process.

To minimize friction losses on the surfaces of the projections which come into contact with each other, in a further design of the invention the cross-section of the projections has a convex outer contour.

In a further design of the invention, the projections take the form of a segment of a sphere or cylinder aligned parallel to the axis of the needle.

Finally, in a further design of the invention, the crosssection of each projection in the swivel plane of the fins is confined within an evoluteshaped contour.

Because of the evolute-shaped contour of the projection cross-section concerned, the supporting surface parts of the projections can roll against each other without sliding and thus effectively avoid friction.

If the aim is to split the sleeve and needle along the length, this can be achieved advantageously in that the height of the projections varies over their length extending in the axial direction of the sleeve. Thus the splitting process begins on the sleeve side to which is allocated the maximum projection height and continues after a corresponding twist of the fins with the projections in the direction of the sleeve side with the minimum projection height. The same effect is also achieved easily if the wall thickness of the sleeve and/or the notch depth in the sleeve increases or decreases continuously from one sleeve end to the other.

The drawing shows one design example of a needle according to the invention. Here:

Fig. 1 shows a side view, and Fig. 2 shows a front view.

6 - A needle 1 (shown broken off in Fig. 1) is fitted with notches (not shown) on opposite longitudinal sides and which extend over the entire length of the needle 1 so that this 5 can be split into two longitudinal halves.

The proximal end of the splittable needle 1 is surrounded by a sleeve 2 into the preferably transparent material of which the already pre-split ends of needle 1 are inserted. As Fig. 2 shows, the sleeve 2 is f itted with notches 3, 4 on opposite longitudinal sides which extend over the length of the sleeve 2. The notches 3, 4 def ine two halves 5, 6 of sleeve 2, each of which is fitted with a fin 8 via a projection 7. The fins 8 projecting radially from the sleeve 2 extend over the main part of the length of sleeve 2 and are angled towards each other to enclose an angle of 5513.

on the sides of fins 8 facing each other, in the vicinity of 20 the central axis of needle 1, are arranged projections 9. The mirror-image arrangement of the projections 9 means that these rest against each other as soon as the f ins 8 are swivelled towards each other through a specific angle. As a result of this swivel movement about the central axis of the needle, aided by the notch 3, sleeve 2 is placed under tension in its lower part (as viewed in the drawing) and split.

t 7 - On the continued swivel movement of the fins 8, under further reduction of the angle enclosed by the fins 8, around a swivel axis now displaced into the rest area of the projections 9, the upper part of sleeve 2 (as viewed in the drawing), supported by notch 4, is placed under tension and split.

Using f ins 8 as handles, the needle 1 can finally be easily split into two completely separate longitudinal needle 10 halves over its entire length.

Claims

Needle splittable into two longitudinal halves, the proximal end of which is fitted with a sleeve also splittable into two longitudinal halves which has axially aligned notches on opposite longitudinal sides and which encloses in each thus defined sleeve half a pre-split end piece of the needle, wherein a radially projecting fin is formed on each sleeve half and the axially aligned fins enclose an angle of <900, characterized in that at least one fin (8) is fitted with a projection (9) on its side facing the other f in (8) in the vicinity of the central axis of the needle (1) -
2. Needle according to Claim 1, characterized in that the two fins (8) each have on their sides facing each other a projection (9) arranged such that the projections (9) come to rest upon each other after a swivel movement of the fins (8) towards each other which can partly split the sleeve (2), and such that further swivel movement of the fins (8) about the rest point can split the sleeve (2) completely.
3. Needle according to Claim 1 or 2, characterized in that the crosssection of the projections (9) has a convex outer contour.

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4. Needle according to one of Claims 1 to 3, characterized in that the projections (9) are each formed in the shape of a segment of a sphere or cylinder aligned parallel to the axis of the needle (1).
Needle according to one of Claims 1 to 3, characterized in that the crosssection of each projection (9) is limited by an evolute-shaped contour in the swivel plane of the fins (8).
6. Needle according to one of Claims 1 to 5, characterized in that the height of the projections (9) varies along their length extending in the axial direction of the sleeve (2).