IE902149A1

IE902149A1 - A Syringe

Info

Publication number: IE902149A1
Application number: IE214990A
Authority: IE
Inventors: Bang Young Choul
Original assignee: Bang Young Choul
Priority date: 1989-06-15
Filing date: 1990-06-14
Publication date: 1991-06-19
Also published as: CA2018363C; NO902623L; ES2054150T3; NO902623D0; NO176005B; CA2018363A1; KR910004532Y1; ATE105717T1; EP0402908B1; IE64714B1; EP0402908A1; IE902149L; JPH0397468A; PT94379A; KR910000318U; DK0402908T3; DE59005710D1; JPH0649071B2; NO176005C

Abstract

The invention relates to an injection syringe (1) with a barrel (2) to whose one end an injection needle (11) can be attached, and with a piston (6) which is displaceable in the barrel (2) and to which a piston rod (5), projecting from the other end of the barrel (2) and provided at its end with an actuating handle (23), can be attached, characterised by a device (16, 20) for automatic locking of the piston (6), pushed forward over a predetermined distance towards the injection needle (11), against retraction of the piston (6). <IMAGE>

Description

The invention relates to a syringe with a barrel on one end of which a needle can be mounted, and with a plunger which is movable within the barrel and to which is attached a plunger shaft extending out of the other end of the barrel and provided with a handle.

The object of the invention is to propose a syringe of this type from which, when used properly, only a single injection can be administered and which thus makes the transmission of disease impossible.

A solution to this problem is characterised by a device for automatically locking the plunger against retraction when said plunger has been pushed forward toward the needle beyond a predetermined distance. This solution ensures that, after a single use of the syringe, its plunger is locked in a forward position, corresponding to the emptied state, preventing renewed retraction for filling and re-use of the syringe, so that re-use of the syringe after single use is effectively prevented.

A further solution to the problem, which can also be applied together with the first solution, and which prevents contact with any part of the entire length of the injection needle, including its tip, after use of the syringe, the needle now being unsterile and possibly infected with pathogens, is characterised as follows: the needle is located on a needle holder attached to the barrel by a rotational joint which can be released by rotation and, optionally, axial displacement of the needle holder in the barrel, and rotation limiting elements are provided on the needle holder and on the plunger, which elements engage one another when the plunger has been pushed forward towards the needle holder beyond a predetermined distance and which allow release of the rotational joint by rotation of the handle and subsequent retraction of the plunger, the needle holder and the entire length of the needle into the barrel. This solution ensures that the needle mounted on the needle holder can be completely withdrawn into the barrel after use, so that the injection needle, and in particular the tip thereof, is protectively surrounded by the barrel and is effectively inaccessible. For this purpose, after the injection, the plunger is rotated by means of its attached handle until rotation limiting elements thereon and on the needle holder engage one another, and subsequently, by further rotation of the handle, the rotational joint between the needle holder and the barrel is released. The injection needle, the needle holder and the plunger now form a single unit and can be withdrawn with the handle so far into the barrel that the injection needle, including its tip, can no longer be touched, and infection is effectively prevented.

In order to prevent the plunger, the needle holder and the injection needle being withdrawn from the rear end of the barrel, remote from the injection needle, and also to prevent renewed forward movement into the original position in which the injection needle is exposed, there is preferred an embodiment characterised by a device for the automatic locking, against forward movement, of the combination of plunger, needle holder and needle, which combination has been withdrawn by more than a predetermined distance into the barrel.

A particularly simple embodiment of the locking device between the plunger and the needle holder or between the plunger and the barrel, which embodiment is especially reliable without necessitating additional components, is achieved by an embodiment wherein at least one of the devices for automatic locking is formed by at least one nose-shaped projection and a nose-shaped recess complementary thereto, which yield with respect to one another.

An embodiment wherein the needle is secured to the needle holder by a rotational joint which can be released from the needle holder by turning free and, optionally, by axial displacement of the needle, allows rapid assembly and a secure attachment of the injection needle to the needle holder.

In order to prevent accidental release of the rotational joint between the needle holder and the barrel, it is preferred that the rotational joints be of opposite handedness.

When at least one of the rotational joints is a screw joint, this presents a detachable rotational joint which is, at the same time, a good seal against the fluid pressure within the syringe during injection .

When the rotation limiting elements are angularly spaced apart bars which can be meshed, this allows particularly easy and secure engagement of the rotation limiting elements on the plunger with those of the needle holder, without necessitating rotation of the plunger to a specific axial angle with respect to the needle holder.

Two embodiments of the invention are described with reference to the attached drawings in what follows.

In the drawings, Fig 1 shows a longitudinal section through the front part of a syringe in accordance with a first embodiment; Fig 2 shows a longitudinal section through the syringe of Fig 1 with largely retracted plunger; Fig 3 shows a longitudinal section through the syringe of Fig 1 after injection; Fig 4 shows a longitudinal section through the front part of the syringe of Fig 1 after injection, with the plunger locked into place in the needle holder; Fig 5 shows a longitudinal section through the front part of the syringe of Fig 1 after release of the needle holder from the barrel; Fig 6 shows a longitudinal section through the syringe of Fig 1 with the plunger withdrawn together with the needle holder and the needle into the barrel and secured by engagement within the barrel.

Fig 7 shows a longitudinal section through the front part of a syringe in accordance with a second exemplary embodiment, with the plunger secured by engagement within the needle holder.

The syringe 1 of Figs 1 to 6 has a barrel 2 of uniform diameter, in which a plunger shaft 5 is slidably inserted, a needle mounting sleeve 3 for a needle 11, a needle holder 4 for the needle mounting sleeve 3 and a plunger 6 which is integral with the plunger shaft 5. The barrel 2 is provided with an internal screw-threaded section 8 moulded into its inner wall 7 in a narrow front region, into which screw-threaded section the needle holder 4 is screwed. Into the rear part of the barrel 2 a nose-shaped locking projection 9 is moulded with which nose-shaped locking recesses 25 in the guide ribs 24 on the plunger shaft 5 can engage. Said guide ribs 24 are arranged in cross-shaped formation around said plunger shaft 5. Finger supports 10 are located on the outside of the rear end of the barrel 2, which supports are complementary to a round grip handle 23 at the free end of the plunger shaft 5, by means of which grip handle the plunger shaft 5 can be rotated and slid.

In the front end of the needle mounting sleeve 3 the needle 11 is immovably secured. A flange 12 is moulded onto the outside of the rear end of the needle mounting sleeve 3. A left-handed screw-threaded section 13 is moulded into an inner wall surface 14 of the needle holder 4, into which the flange 12 of the needle mounting sleeve 3 can be screwed. A right-handed screw-threaded section 15 is moulded into the outer periphery of the rear mid-section of the needle holder 4, which threaded section is screwed by hand or by machine into the inner screw-threaded section 8 of the barrel 2.

The needle holder 4 is provided at its rear with a cavity 17. A nose-shaped locking projection 16 formed on the needle holder 4 projects into the cavity 17. Radially disposed integral bar-like rotation limiting elements 18 project from the inner wall of the needle holder 4 surrounding the rear of the cavity 17. The front mid-section of the needle holder 4 is penetrated by a channel 19, through which fluid to be injected reaches the injection needle 11.

The nose-shaped locking projection 16 in the cavity 17 of the needle holder 4 yields to engage a nose-shaped locking recess 20 on a front extension of the plunger 6. The locking recess 20, which locks together with the locking projection 16 of the needle holder 4, and bar-like rotation limiting elements 21 for interlocking engagement with the rotation limiting elements 18 of the needle holder 4 project radially from the outer periphery of the plunger 6. A rubber O-ring 22 which lies snugly against the inner wall 7 of the barrel 2 is secured to the periphery of the plunger 6.

The guide ribs 24, arranged in cross-like formation, and the plunger shaft 5 are adhesively secured to the round handle 23. The nose-shaped locking projection 9 on the barrel 2 yields for positively engaging the nose-shaped locking recesses 25 in the plunger 6 when the plunger 6 is drawn back, and prevent complete withdrawal of the plunger shaft 5 from the barrel 2.

Before use the needle holder 4 is screwed together with the needle mounting sleeve 3 in a direction contrary to the screw joint between the needle holder 4 and the barrel 2, after which a needle cap indicated by a broken line in Fig 1, is removed. When an injection fluid has been injected into a body by forward movement of the plunger 6, the plunger 6 is roughly in the position shown in Fig 3 In this position the injection needle 11 is withdrawn from the body and the plunger 6 is then pushed further forward into the position of Fig 4, whereby the locking recess 20 of the plunger 6 engages the locking projection 16 in the cavity 17 of the needle holder 4, so that the plunger 6 is joined to the needle holder 4 within the barrel 2.

Fig 7 shows a second exemplary embodiment, in which the right-handed screw-threaded section 15 in the outer periphery of the needle holder 4, which is screwed into the inner threaded section 8 of the barrel 2, is shown in simplified form compared with the first embodiment. In contrast with the first exemplary embodiment, no inner screw-threaded section 13 is provided in an inner wall face 14 of the needle holder 4. Rather, an extension 27 is integrally moulded onto the needle holder 4, on which the needle mounting sleeve 3 can be sealingly and immovably mounted.

In the following the manipulation and functioning of the syringe 1 according to the first exemplary embodiment will be described.

To establish the screw joint between the needle holder 4 and the barrel 2 the needle holder 4 is inserted into the rear end of the barrel 2, pushed forwards and then turned clockwise between about a quarter and a full revolution, either manually or by machine, until the inner threaded section 8 on the inner wall 7 of the barrel 2 has securely embraced the right-handed screw-threaded section 15 on the outer periphery of the needle holder 4. The flange 12 on the needle mounting sleeve 3 is then screwed into the left-handed screw-threaded section 13 of the needle holder 4. Thus the sense of the screw joint between the needle 11 and the needle holder 4 is opposite to the sense of the screw joint between the barrel 2 and the needle holder 4.

After the needle mounting sleeve 3 has been attached and after the needle cap 26, which covers the injection needle 11 as shown by the dot-and-dash line in Fig 1, has been removed, the injection needle 11 is inserted into a body. The plunger 6 is then pushed forward by means of the plunger shaft 5 from the position of Fig 2 into the position of Fig 3 .

After the injection has been carried out the injection needle 11 is withdrawn from the body and the plunger shaft 5 is pushed forward by means of the handle 23 into the position of Fig 4, ie until the bar-like rotation limiting elements 21 on the front extension of the plunger 6 mesh with the bar-like rotation limiting elements 18 on the needle holder 4 and the front extension of the plunger 6 has been pushed into the cavity 17 of the needle holder 4. The nose-shaped locking projection 16 on the needle holder 4 and the nose-shaped locking recess 20 in the front extension of the plunger 6 then engage one another. This manner of locking between the locking projection 16 and the locking recess 20 unites the plunger 6 securely with the needle holder 4 and prevents re-use of the syringe 1.

When the plunger 6 is turned further in a clockwise direction, the bar-like rotation limiting elements 18 in the cavity 17 of the needle holder 4 come into contact with the bar-like rotation limiting elements 21 on the extension of the plunger 6. By further turning of the plunger 6 between about one quarter and a full revolution the screw joint between the inner threaded section 8 in the barrel 2 and the right-handed threaded section 15 on the needle holder 4 is released, as in Fig 5.

The plunger 6 is then drawn back until the nose-shaped locking projection 9 on the inner wall 7 of the barrel 2 clicks into the nose-shaped locking recesses 25 in the guide ribs 24, arranged crosswise. Displacement of the needle mounting sleeve 3, the needle holder 4 and the plunger 6 from the position of Fig 6 is thus prevented.

The injection needle 11 thus lies completely within the barrel 2, so that it can not cause infection.

The manipulation and functioning of the injection syringe 1 in accordance with the second exemplary embodiment are analogous, apart from the push fit between the needle mounting sleeve 3 and the projecting extension 27 on the needle holder 4.

While the present invention has been more particularly described with reference to an injection syringe, the invention is also applicable to an extraction syringe, with suitable modifications

Claims

1. A syringe with a barrel on one end of which a needle can be mounted, and with a plunger which is movable within the barrel and to which is attached a plunger shaft extending out of the other end of the barrel and provided with a handle, characterised by a device for automatically locking the plunger against retraction when said plunger has been pushed forward toward the needle beyond a predetermined distance .

2. A syringe with a barrel on one end of which a needle can be mounted, and with a plunger which is movable within the barrel and to which is attached a plunger shaft extending out of the other end of the barrel and provided with a handle, especially in accordance with Claim 1, characterised in that the needle is located on a needle holder attached to the barrel by a rotational joint which can be released by rotation and, optionally, axial displacement of the needle holder in the barrel, and that rotation limiting elements are provided on the needle holder and on the plunger, which elements engage one another when the plunger has been pushed forward towards the needle holder beyond a predetermined distance and which allow release of the rotational joint by rotation of the handle and subsequent retraction of the plunger, the needle holder and the entire length of the needle into the barrel.

3. A syringe according to Claim 2, characterised by a device for the automatic locking, against forward movement, of the combination of plunger, needle holder and needle, which combination has been withdrawn by more than a predetermined distance into the barrel.

4. A syringe according to one of the preceding claims, characterised in that at least one of the devices for automatic locking is formed by at least one nose-shaped projection and a nose-shaped recess complementary thereto, which yield with respect to one another.

5. A syringe according to one of Claims 2 to 4, characterised in that the needle is secured to the needle holder by a rotational joint which can be released from the needle holder by turning free and, optionally, by axial displacement of the needle.

6. A syringe according to Claim 5, characterised in that the rotational joints are of opposite handedness .

7. A syringe according to one of Claims 2 to 6, characterised in that at least one of the rotational joints is a screw joint.

8. A syringe according to one of Claims 2 to 7, characterised in that the rotation limiting elements are angularly spaced apart bars which can be meshed.

9. A syringe as recited in the preamble to Claim 1 herein, substantially as herein described with reference to or as illustrated either in Figs 1-6, or in Fig 7 of the accompanying drawings.