AU648447B2

AU648447B2 - Improvements in or relating to skin-puncturing instruments

Info

Publication number: AU648447B2
Application number: AU28587/92A
Authority: AU
Inventors: John Stewart Parry
Original assignee: Sterimatic Holdings Ltd
Current assignee: Sterimatic Holdings Ltd
Priority date: 1988-10-05
Filing date: 1992-11-25
Publication date: 1994-04-21
Anticipated expiration: 2009-09-21
Also published as: AU2858792A; GB8823349D0; GB8910251D0; IN173225B; ZA897124B

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

648447 Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: a 4 a.

*0 a a.

Name of Applicant: Sterimatic Holdings Limited Actual Inventor(s): John Stewart Parry Address for Service: a PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA *c a a. a a Invention Title: IMPROVEMENTS IN OR RELATING TO SKIN-PUNCTURING INSTRUMENTS Our Ref 312014 POF Code: 1148/20775 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- 6006 IMPROVEMENTS IN OR RELATING TO SKIN-PUNCTURING INSTRUMENTS This application is a divisional application of Australian Patent Application No: 43286/89, the specification of which is herein incorporated by reference.

This invention relates to skin-puncturing instruments, such as syringes, and accessories therefor.

After use of a syringe to perform an injection or take up a sample of blood from a patient, there is a risk that doctors or nurses will accidentally prick themselves with the needle of the syringe. This phenomenon is known as "needle stick" and can be highly dangerous due to the 15 risk of transfer of blood-related diseases.

European Patent Specification No. 0268445A discloses an accessory for a skin-puncturing instrument having a needle, the accessory comprising a protective shield for .i S 20 surrounding the needle and having two shield parts which are movable relative to one another in the direction of the length of the needle from a contracted position, in which the point of the needle projects from the shield to an extent to enable a skin-puncturing operation to be 25 effected, to an extended position, in which the point of oe I S"the needle is located within the shield to shield the point of the needle. Such an accessory will be referred to hereinafter as "an accessory of the type referred to".

S 30 In order to substantially eliminate the danger of needle stick after the skin-puncturing operation has been performed, such an accessory may include retaining means for retaining the shield in the extended position after the skin-puncturing operation has been effected and la -2for preventing the point of the needle from being exposed solely by application of pressure to the end of the shield in the direction of contracting movement, and biasing means for resiliently biasing the shield towards its extended position.

It is to be understood that the term "skinpuncturing instrument" includes within its scope an instrument, such as a syringe or a drip feed, for introducing a substance into a site penetrated by a 10 needle, and an instrument, such as a blood collection needle, for taking up a substance from a site penetrated by a needle.

It is an object of the present invention to provide an improvement of the accessory of the type 15 referred to.

According to the present invention there is provided an accessory of the type referred to, further comprising retaining means for retaining the shield in the extended position after the skin-puncturing operation 20 has been effected and for preventing the point of the needle from being exposed solely by application of pressure to the end of the shield in the direction of contracting movement, characterised in that the retaining means comprises, on one of the shield parts,, locking tongue within a recess in the wall of said one shield part, the locking tongue being pivotable within the recess between a locking position and a disei.aged position and being resiliently biased towards its locking position, and, on the other shield part, a shoulder which is positioned such that, during movement of the shield from its contracted position to its extended position, the locking tongue overrides the shoulder and, in so doing, is pivoted from its disengaged position into its locking position by resilient action so that it engages behind the shoulder to retain the shield in its extended position.

Preferably biasing means, such as a compression spring, is provided for resiliently biasing the shield V 10 towards its extended position so that it will automat cally assume its extended position, and be retainez therein by the retaining means, on removal of pressure from the end of the shield after a skinpuncturing operation has been performed.

15 Such a locking arrangement is advantageous as it S ft enables the dual requirements to be satisfied that (i) there is no danger of the point of the needle being reexposed by application of pressure to the end of the shield in the direction of contracting movement (for 20 example by accidentally pressing the shield against a person's skin), and the shield can be locked in the extended position under spring pressure without requiring the use of a strong compression spring which would prejudice the fine control of the accessory which is particularly desirable under clinical conditions.

By contrast, the locking arrangement shown in Figure 5 of European Patent Specification No. 0268445A requires a substantial spring force to cause the shield to -4be locked in its extended position. The provision of a strong spring will not allow delicate control on insertion of the tip of the needle into the patient, but will result in application of undesirable pressure to the skinpuncturing site by the end portion of the shield.

Moreover, after locking, it may be possible to re-expose the point of the needle simply by application of pressure to the end of the shield in the direction of contracting movement.

Preferably the locking tongue is part of a collar forming a portion of said one shield part which is formed separately from the remainder of said one shield *part and which is fitted thereto during assembly. Such an arrangement provides for ease of manufacture and enables 15 the locking tongue to be formed in the collar, and the collar to be subsequently inserted into an end portion of the shield so that the locking tongue is enclosed by a surrounding wall of the shield.

In order that the invention may be more fully .i 20 understood, a preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through the accessory in a final locked position; Figure 2 is a section through a collar of the outer sleeve part showing a portion of the track provided on the inside surface of the outer sleeve part; Figure 3 is a section through the collar showing a locking tongue provided on the inside surface of the outer sleeve part diametrically opposite the track; Figure 4 is a longitudinal section through the inner sleeve part taken along the line IV-IV in Figure 6; Figure 5 is a part section through the inner sleeve part taken along the line V-V in Figure 6; and Figure 6 is a cross-section taken along the line VI-VI in Figure 4.

Referring to Figure i, the accessory shown therein comprises a protective sleeve 1 integrally formed with a hollow needle 2. The sleeve 1 consists of an inner sleeve part 3 having a tapered end portion 4 and an outer sleeve part 5. The outer sleeve part 5 has a collar 6 which is a snap fit within an annular recess 7 in the 15 inside surface of an end portion of the outer sleeve part 5. Furthermore the outer sleeve part 5 is provided with a connector 9 through which the needle 2 extends and by means of which the sleeve 1 is attached to the outlet of a syringe.

S. 20 A compression spring 8 is accommodated within the outer sleeve part 5 and acts between the connector 9, which is fixed in position as by sonic welding, and a shoulder 10 on the inside surface of the inner sleeve part 3. The inner and outer sleeve parts 3 and 5 are fitted together so that the inner sleeve part 3 is capable of being telescoped within the outer sleeve part 5 against the action of the spring 8 in order to enable the point of the needle 2 to project through an aperture 11 at the end -6of the inner sleeve part 3 to an extent to permit an injection to be effected, but so that the inner sleeve part 3 is automatically moved into an extended position, as shown in Figure 1, to shield the point of the needle when the injection has been carried out, as will be described more fully below.

The inner sleeve part 3 is retained in engagement with the outer sleeve part 5 when in its extended position by engagement of an annular shoulder 12 on the outside of the inner sleeve part 3 with an annular shoulder 13 on the inside of the collar 6. Furthermore the outside surface of the inner sleeve part 3 has an outwardly extending projection 14 (see Figure 4 which shows the part 3 in longitudinal section transverse to 15 the longitudinal section of Figure 1) which engages within a track 14A (shown in broken lines) on the inside surface of the outer sleeve part 5 including the collar 6.

As shown in the section of Figure 2 showing a portion of the inside surface of the collar 6, the track 20 14A incorporates a slot 15 extending through the wall of the collar 6. When the collar 6 is fitted within the recess 7 in the end of the outer sleeve part 5, the slot forms a channel which communicates with a portion of the track 14A formed by a rectilinear channel 16 in the inside wall of the outer sleeve part 5, as shown diagrammatically in broken lines in Figure 2. During assembly of the sleeve 1 before the collar 6 is fitted in the end of the outer sleeve part 5, the projection 14 on -7the inner sleeve part 3 is introduced into a position as shown in broken lines, within the slot 15 in which it is in engagement with a shoulder 22. This requires some deformation of the wall of the collar 6 so that, when the projection 14 is seated within the slot 15 and the collar 6 is subsequently fitted in the recess 7 in the outer sleeve part 5, the projection 14 can no longer be moved out of the track 14A.

When the sleeve 1 is fully assembled, the 10 location of the projection 14 in the position 20 retains the inner sleeve part 3 in a partially contracted position in which the point of the needle 2 projects slightly from Se S.the aperture 11. The accessory may be supplied to the user in this state, a removable cap 40 (see Figure 1) 15 having internal ribs 41 being provided as an interference fit on the end of the sleeve 1 to shield the point of the needle 2. When an injection is to be performed, with the sleeve 1 attached to the outlet of a syringe which is prefilled with injectate, the cap 40 is removed to expose 20 the point of the needle 2, and the point of the needle 2 may then be accurately positioned at the injection site, for example at the site of a vein.

In a modification shown in broken lines in Figure 2, the projection 14 is initially in a temporary catch position 17 defined by an extension 19 of the slot so that the inner sleeve part 3 is initially in its extended position shielding the point of the needle 2 (in which case a removable cap is not required). In use of -8this modification the point of the needle 2 is exposed for location at the injection site by manually grasping the inner sleeve part 3 and applying a slight twist to snap the projection 14 out of the temporary catch position 17, and by then applying slight pressure to telescope the inner sleeve part 3 within the outer sleeve part 5 to cause the projection 14 to travel along the slot extension 19 until a click and a slight twist are felt as the projection 14 engages in the position 10 After the point of the needle 2 has been located at the required injection site, the action of inserting the needle into the patient will cause the inner sleeve ""*part 3 to telescope within the outer sleeve part 5 by the action of the end of the inner sleeve part 3 being pressed 15 against the skin of the patient. This will cause the projection 14 to move beyond a finger portion 21, which is resiliently displaced to allow free passage for the projection 14, and to travel along the channel 16 on the inside wall of the outer sleeve part 5. Since the channel 20 16 extends in the direction of the length of the needle, there is no relative twisting between the two sleeve parts during such movement.

On withdrawal of the needle from the patient after the injection has been effected, the projection 14 automatically returns along the track 14A under the effect of the spring 8 as the inner sleeve part 3 moves out of the outer sleeve part 5 on release of the contact pressure between the end of the inner sleeve part 3 and the -9patint's skin. When the projection 14 contacts the finger portion 21, however, it is directed by the finger portion 21 to a final position 23 which is angularly offset from the position 22. In this final position 23 of the projection 14 the sleeve 1 is in its fully extended position in which it is preferably retained in a manner described below so as to shield the point of the needle 2 and prevent the point of the needle 2 from subsequently being exposed with consequent risk of the user being 10 pricked by the contaminated point of the needle.

The retaining or locking arrangement will now be described with reference to Figures 3 to 6. Figure 3 Sshows a further portion of the inside surface of the collar 6 having a locking tongue 25 within a cutout 26 in 15 the wall of the collar 6. The locking tongue 25 is joined to the remainder of the collar 6 by a resiliently flexible neck 30 permitting sideways deflection of the •locking tongue 25 in the direction of the arrows 31 within the cutout 26. The locking tongue 25 is thicker than the 20 wall of the remainder of the collar 6 so that it projects into a longitudinal recess 21 (see Figures 4 and 6) in the outside surface of the inner sleeve part 3 which extends from the level of the shoulder 12 to the inner end of the inner sleeve part 3. The locking tongue 25 has no effect on the movement of the inner sleeve part 3 within the outer sleeve part 5 until the projection 14 moves to the final position 23 in which the paint of the needle 2 is shielded by the sleeve i.

There is also shown in Figure 3 a rib 24 on the inside surface of the collar 6 which prevents the inner sleeve part 3 from being twisted relative to the outer sleeve part 5 on removal of the cap 40, due to the fact that the rib 24 and the locking tongue 25 engage opposite sidewalls of the recess 27 when the projection 14 is in the position When the projection 14 contacts the finger portion 21 on the return of the projection 14 along the track 14A after the injection has been effected, the resulting angular displacement of the inner sleeve part 3 relative to the outer sleeve part 5 results in the shoulder 12 on the inner sleeve part 3 contacting the inclined side surface 32 of the locking tongue 25 and 15 displacing the locking tongue 25 sideways in the direction e of the arrow 31. At the same time the rib 24 on the inside surface of the collar enters a groove 29 in the ••outside surface of the inner sleeve part 3. As the projection 14 moves to its final position 23, the shoulder 20 12 moves beyond the locking nose 33 of the tongue 25, so that the tongue 25 resilir-itly snaps into a recess 28 which extends from the inner end of the inner sleeve part 3 to a position short of the shoulder 12, as shown in Figure 5. The locking nose 33 engages beneath a shoulder 34 (see Figure 5) on the inner sleeve part 3 and prevents the inner sleeve part 3 from being subsequently moved inwardly of the outer sleeve part 5. This locking action will occur even if the neck 30 connecting the locking -11tongue 25 to the remainder of the collar 6 is fractured since the thickness of the locking tongue 25 will still ensure that the locking tongue 25 serves as a locking wedge.

The above-described locking arrangement has certain advantages in terms of ease of fabrication.

However, it should be appreciated that other locking arrangements are possible within the scope of the invention, and in particular alternative locking ee arrangements can be contemplated in which a locking tongue provided which is resiliently movable in one or other *of the two directions perpendicular to the direction of the arrow 31.

It will be appreciated that this protective 15 sleeve 1 not only guards against needle stick, but also prevents the needle from being used more than once. This is a particularly important feature as it guards against .:ooei S•transmission of blood-related diseases by multiple use of needles, and needle stick injuries during use and 20 subsequent disposal. Furthermore, if the sleeve is integrally formed with the syringe or is attached to the syringe in such a manner that it cannot be subsequently removed, this also prevent the syringe from being used more than once.

Other modificatIons are possible, for example where the sleeve is to be used for taking a sample of blood from a patient. Where the sleeve is to be used in an evacuated blood collection system, instead of the -12sleeve being adapted for connection to a syringe it may be formed with an extension to the needle provided with a second point and covered with a rubber sleeve closed at one end which projects beyond the second point of the needle. In this known system for taking blood, the second point of the needle is caused to pierce the closure of an evacuated tube after the first point of the needle has been introduced into the patient so as to cause blood to be drawn along the needle into the tube, the rubber sleeve 4 10 acting as a valve to prevent blood leaking from the needle when the needle is removed from the tube.

In a further modification the inner sleeve part is adapted to be temporarily retained within the outer sleeve part in a fully contracted position in which the 15 point of the needle is exposed, this being achieved by locking of the projection in a specially adapted portion of the track, for example. This temporary locking can be overcome by twisting of the inner sleeve part to cause the :....sleeve to adopt its extended position shielding the point 20 of the needle.

The protective sleeve described with reference to the drawings may also be used in a composite sleeve/syringe arrangement of the type described with reference to Figures 6 and 7 of European Patent Specification No. 0268445A.

Claims

1. An accessory for a skin-puncturing instrument having a needle, the accessory comprising a protective shield for surrounding the needle and having two shield parts which are movable relative to one another in the direction of the length of the needle from a contracted position, in which the point of the needle projects from the shield to an extent to enable a skin-puncturing operation to be effected, to an extended position, in 10 which the point of the needle is located within the shield to shield the point of the needle, and retaining means for retaining the shield in the extended position after the skin-puncturing operation has been effected and for preventing the point of the needle from being exposed 15 solely by application of pressure to the end of the shield in the direction of contracting movement, wherein the retaining means comprises, on one of the shield parts, a locking tongue within a recess in the wall of said one shield part, the locking tongue being pivotable within the 20 recess between a locking position and a disengaged position and being resiliently biased towzrds its locking position, and, on the other shield part, a shoulder which is positioned such that, during movement of the shield from its contracted position to its extended position, the locking tongue overrides the shoulder and, in so doing, is pivoted from its disengaged position into its locking position by resilient action so that it engages behind the shoulder to retain the shield in its extended position. -14-

2. An accessory according to claim 1, wherein the locking tongue is part of a collar forming a portion of said one shield part which is formed separately from the remainder of said one shield part and which is fitted thereto during assembly.

3. An accessory according to claim 2, wherein the locking tongue is provided within a cutout in the wall of the collar and is located inwardly of a surroun.Ang wall of the remainder of said one shield part. 0

4. An accessory according to claim 2 or 3, wherein the locking tongue is thicker than the wall of the S.remainder of the collar. S

5. An accessory according to claim 2, 3 or 4, wherein the locking tongue is connected to the remainder .i 15 of the collar by a resiliently flexible neck permitting resilient sideways deflection of the locking tongue.

6. An accessory according to any preceding claim, wherein the locking tongue projectti into a recess in said other shield part. 20

7. An accessory according to any preceding claim, wherein the shield parts comprise an inner shield part and an outer shield part, wherein the recess within which the locking tongue is pivotable is in the outer shield part, and wherein the shoulder is on the inner shield part.

8. An accessory according to any preceding claim, wherein the shield parts comprise a first shield part and a second shield part and are guided relative to one another by a projection on the first shield part engaging within a track on the second shield part, the projection and the track being offset from the locking tongue.

9. An accessory according to claim 8 when appended directly or indirectly to claim 2, wherein said first shield part is an inner shield part and said second shield part is an outer shield part, and the track is formed by a slot extending through the wall of the collar and located inwardly of a surrounding wall of the remainder of the outer shield part.

10. An accessory according to any preceding claim, wherein biasing means is provided for resiliently biasing the shield towards its extended position.

11. An accessory according to claim 1, substantially as herein described with reference to any one of Figures 1 to 6. f2 DATED: 25 November 1992 PHILLIPS ORMONDE FITZPATRICK *Attorneys for: *STERIMATIC HOLDINGS LIMITED 4491Z 15 15 SA B S T R A C T "Improvements in or Relating to Skin-Puncturing Instruments" An accessory for an injection device comprises a protective shield 1 for surrounding the needle 2 and having inner and outer shield parts 3, 5 which are movable relative to one another from a contracted position, in which the point of the needle projects from the shield to enable an injection to be effected, to an extended position, in which the point of the needle is shielded by 1'~1 0 the shield. The shield is biased towards its extended position by a spring 8, and a locking tongue 25 within a *cutout 26 in the wall of a collar 6 forming part of the 0 outer shield part 5 is provided to lock the shield in its extended position and prevent the point of the needle from 15 being exposed solely by application of pressure to the end S. of the shield in the direction of contracting movement. The locking tongue 25 is pivotable within the cutout 26 4SS*SS between a locking position and a disengaged position and is resiliently biased towards its locking position so that, during movement of the shield from its contracted position to its extended position, the locking tongue overrides a shoulder 34 on the inner shield part 3 and, in so doing, is pivoted from its disengaged position into its locking position by resilient action so that it engages behind the shoulder 34 to retain the shield in its extended position. Such an arrangement permits reliable locking using only a weak spring. (Figures 1 and 3)