Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Patent
1997-03-26
1998-03-17
Yasko, John D.
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
604195, 604220, A61M 500
Patent
active
057280738
DESCRIPTION:
BRIEF SUMMARY
THIS INVENTION relates to syringes and in particular syringes of the form which incorporate a retractable needle.
As a result of the need to develop practices which minimise the risk of infection the use of disposable syringes has become commonplace. The principal difficulty of such syringes however relates in the need to prevent the spread of infection as a result of inadvertent "stick" injuries. These can result from accidents during the use of the syringes and the inappropriate disposal of the syringe. In many cases these can be avoided if the pointed needle can be stored in a retracted position when not in use and in particular prior to disposal. In addition it is highly desirable to prevent such syringes from being reused. As a result syringes have been proposed in which the needle can be moved between a retracted position and an extended position. Some of these syringes are provided with a locking means which is able to prevent a used syringe from being reused by lockingly retaining the needle of a used syringe in the retracted position to prevent its reuse. Examples of such syringes are disclosed in the following patent specifications: AU-A-17419/92; U.S. Pat. No. 4,927,414; and U.S. Pat. No. 4,941,883.
A difficulty of such syringes however is that the plunger is still capable of being used to draw and force fluid from the chamber of the syringe which means that if the needle can be disengaged from its locking engagement, the syringe can be reused.
It is an object of this invention to provide a syringe whereby when the needle is located in the retracted position in which it is fully accommodated within the syringe body, it can be locked in that position.
Accordingly the invention resides in a syringe comprising a tubular body closed at one end and open at the other end, a plunger receivable in the body to define a chamber of variable volume, a needle support adapted to support and accommodate a hollow needle, said needle support being supported from, or in the wall of the body and being movable in a direction substantially parallel to the main axis of the body between a first position at which the needle extends from the one end of the body and the interior of the needle is in communication with the chamber and a second position at which the outer end of the needle is in a retracted position, said needle support having a protrusion which is selectively engagable with the wall of the body at the first and second positions to be able to be retained at said positions and receivable through the wall of the body at the second position to be engaged with the plunger to prevent axial movement of both the needle support and the plunger with respect to the body.
According to a preferred feature of the invention the needle support is rotatable about an axis substantially parallel to its direction of movement and said protrusion extends radially from the needle support, whereby rotation of the needle support will cause the protrusion to pass through the wall of the body and engage the plunger.
According to a further preferred feature of the invention the needle support is receivable in a passage provided on or in the wall of the body and is slidable along the passage to enable movement between the first an second position. The passageway can be formed with a longitudinal slot which slidably receives the protrusion. If desired the slot can be formed with a transverse extension at a position corresponding to the position of the protrusion at both the first and the second position whereby rotation of the needle support will cause the protrusion to engage with respective slot when at the first and second position.
According to a further preferred feature an aperture is provided in the wall adjacent the transverse slot at said second position to permit the protrusion to pass through the wall to engage the plunger. The aperture is dimensioned to require resilient deformation of the protrusion and/or the edges of the aperture to permit the passage of the protrusion through the aperture.
According to a further preferr
REFERENCES:
patent: 5263942 (1993-11-01), Smedley et al.
patent: 5300038 (1994-04-01), Haber et al.
patent: 5498245 (1996-03-01), Whisson
Eastland Technology Australia Pty Ltd.
Yasko John D.
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