IE64714B1

IE64714B1 - A syringe

Info

Publication number: IE64714B1
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: 1995-08-23
Also published as: EP0402908A1; CA2018363A1; DK0402908T3; KR910000318U; NO902623D0; ES2054150T3; EP0402908B1; JPH0397468A; PT94379A; KR910004532Y1; IE902149L; NO902623L; NO176005C; CA2018363C; NO176005B; JPH0649071B2; ATE105717T1; DE59005710D1; IE902149A1

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 an injection syringe comprising a cylinder, to one end of which can be attached a needle holder for supporting an injection needle, a piston movable within said cylinder and to which is attached a piston rod projecting from the other end of said cylinder and being provided with a manipulating handle at the end thereof, and means for automatically securing said piston to said needle holder so as to prevent retraction thereof when said piston is advanced a pre-determined amount in the direction of said injection needle, wherein said needle holder is connectable to said cylinder by a rotary connection which can be released by rotation and, if required, by axial displacement of said needle holder in said cylinder, and wherein rotation preventing members are provided on said needle holder and on said piston, which members engage with one another upon advance of said piston in the direction of said needle holder for securing said piston to said needle holder, whereby turning said manipulating handle permits the release of the rotary connection followed by the withdrawal of said piston, said needle holder and said injection needle over their length into said cylinder. 6471 4 - 2 An 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.

The injection syringe of the above kind is characterised in that the rotation preventing members are angularly spaced apart spines, arranged to be brought into mutual meshing engagement by axially advancing said piston.

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.

Contact is prevented 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. 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 )Q 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. 2Q 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 or rotary connection needle holder by a rotational jointy 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.

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 5 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 15 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. or cylinder The syringe 1 of Figs 1 to 6 has a barrel/ 2 of or constant or piston rod uniformydiameter, in which a plunger shaft/5 is or holder slidably inserted, a needle mountingysleeve 3 for a needle 11, a needle holder 4 for the needle mounting or piston sleeve 3 and a plungerye which is integral with the plunger shaft 5. The barrel 2 is provided with an or portion internal screw-threaded sectiony8 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 or lug-shaped or protrusion nose-shapedyloclcing projection/ 9 is moulded with or lug-shaped which nose-shapedylocking recesses 25 in the guide ribs 24 on-the plunger shaft 5 can engage. Said (are cruciform in cross-section) 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 . or manipulating 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 or portion screw-threaded sectionyl3 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 or portion screwed. A right-handed screw-threaded sectxon/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 or lug-shaped or protrusion cavity 17. A nose-shapedylockxng projectiory 16 formed on the needle holder 4 projects into the cavity 17. Radially disposed integral bar-like the inner rotation limiting or preventing elements members 18 project from / 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 of the needle holder 4 yields to engage a or 1u cruciform · 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. ig 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 x exemplary embodiment, no inner screw-threaded section 13 is provided in an inner wall face 14 of or attachment the needle holder 4. Rather, an extensiony27 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 5 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 <15 outer periphery of the needle holder 4. The flange 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 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. 3y 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 10 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. An injection syringe (1) comprising a cylinder (2) to the one end of which can be attached a needle holder (4) for supporting an injection needle (11), a piston (6) movable within said cylinder (2) and to which is attached a piston rod (5) projecting from the other end of said cylinder (2) and being provided with a manipulating handle (23) at the end thereof, and means for automatically securing said piston (6) to said needle holder (4) so as to prevent retraction thereof when said piston is advanced a predetermined amount in the direction of said injection needle (11), wherein said needle holder (4) is connectable to said cylinder (2) by a rotary connection (8, 15) which can be released by rotation and, if required, by axial displacement of said needle holder (4) in said cylinder (2) , and wherein rotation preventing members (18, 21) are provided on said needle holder (4) and on said piston (6) which members engage with one another upon advance of said piston (6) in the direction of said needle holder (4) for securing said piston (6) to said needle holder (4), whereby turning said manipulating handle (23) permits the release of the rotary connection (8, 15) followed by the withdrawal of said piston (6), said needle holder (4), and said injection needle (11) over their length into said cylinder (2), characterised in that said rotation preventing members (18, 21) are angularly spaced apart spines (18, 21) arranged to be brought into mutual meshing engagement by axially advancing said piston (6).

2. An injection syringe according to claim 1 characterised by means (9, 25) for automatically securing the combination (6, 4, 11) of piston (6), needle holder (4), and injection needle (11), when drawn into said cylinder (2) by a predetermined amount, - 13 against advance of said combination (6, 4, 11).

3. An injection syringe according to any of the preceding claims, characterised in that at least one of said means (16, 20; 9, 25) for automatically securing is formed by at least one lug-shaped protrusion (16; 9) and a complementary lug-shaped groove (20; 25) which are resilient relative to one another.

4. An injection syringe according to any of claims 1 to 3, characterised in that said injection needle (11) is engageable with said needle holder (4) by a rotary connection (12, 13) which is releasable from said needle holder by rotation in the opposite direction from the first-mentioned rotary connection (8, 15) and, if required, axial displacement of the injection needle (11) in said needle holder (4).

5. An injection syringe according to any of the claims 1 to 4, characterised in that at least one of said rotary connections (8, 15; 12, 13) is a screw connection.

6. A syringe as defined in Claim 1 substantially as herein described with reference to or as illustrated either in Figs. 1 - 6, or in Fig.

7. Of the accompanying drawings.