Syringe needle abstract
A telescoping guard for a hypodermic syringe needle assembly has
an inner section that is securely connected to the upper section
of a standard needle assembly hub. The guard can be telescopically
extended to afford full protection for the cannula of the needle
assembly, and can be contracted to clear the cannula for use without
any interference with the syringe barrel. The guard allows use of
a standard cannula cap on the standard needle assembly.
Syringe needle claims
What is claimed is:
1. A protected needle assembly for a hypodermic syringe comprising:
a standard needle assembly hub having upper and lower sections,
means on said hub for connecting the assembly to a syringe barrel,
a cannula fixed to said lower section and having an insertion tip
positioned outwardly of said lower section, and
a longitudinally extensible and collapsible protective sleeve having
an inner end fixedly secured to and circumscribing said hub upper
section and having an outer end radially outwardly spaced from said
hub lower section and extending to said cannula insertion tip when
said sleeve is longitudinally extended, said sleeve being longitudinally
collapsible to a contracted position in which said sleeve outer
end is positioned inwardly of said cannula tip to expose the cannula
tip for use of the syringe.
2. The assembly of claim 1 wherein said hub upper section has a
relatively larger exterior diameter and said hub lower section has
a relatively smaller exterior diameter, and including a tubular
cap extending over said cannula and having an open inner end that
is a hand tight friction fit on said relatively smaller diameter
lower hub section, said cap having an inner end positioned between
said sleeve and said lower hub section.
3. The assembly of claim 1 wherein said sleeve inner end comprises
a sleeve inner end section, said inner end section having a connecting
portion frictionally secured to said hub upper section.
4. The assembly of claim 3 wherein said connecting portion has
a first interior diameter, wherein said sleeve inner end section
has an outer end portion having an interior diameter greater than
said first interior diameter, said outer end portion extending along
and being radially spaced from said hub lower section to provide
an annular space between the sleeve inner end section and the hub
lower section for reception of a tubular cannula cap.
5. The assembly of claim 3 wherein said connecting portion includes
a bore having a reduced internal diameter, said reduced internal
diameter bore being a hand tight friction fit on the exterior surface
of said needle hub upper section.
6. The assembly of claim 4 including a cannula cap frictionally
secured to said hub lower section between said outer end portion
and said hub lower section.
7. The assembly of claim 1 wherein said connecting portion of said
sleeve inner end section includes thread means extending radially
outwardly.
8. The assembly of claim 7 wherein said sleeve includes three telescopically
inter-engaged sections which include said sleeve inner end section,
a sleeve outer end section, and an intermediate section connected
to both said inner and outer end sections, said sleeve outer end
forming part of said outer end section.
9. A hypodermic syringe comprising:
a syringe barrel,
a needle connecting fitting having an externally tapered neck secured
to an end of said barrel, and
a guarded needle assembly secured to said fitting, said guarded
needle assembly comprising:
a hub and a cannula secured to the hub, said hub having a bore
that is a tight friction fit on said connecting fitting neck, and
a longitudinally extensible and contractible guard sleeve secured
to said hub, said guard sleeve being movable between a contracted
position in which a major portion of the cannula is free of and
extends beyond the guard sleeve, and an extended position in which
the guard sleeve extends to the end of the cannula, said barrel
including an internally threaded tip sleeve radially spaced from
and circumscribing said needle connecting fitting, said guard sleeve
including an inner section connected to said needle hub, said inner
section having outwardly projecting teeth in threaded engagement
with said internally threaded tip sleeve.
10. The syringe of claim 9 wherein said guard sleeve includes a
plurality of telescoping sections interengaged with one another,
said sections including an inner section having an end of decreased
interior diameter snugly engaging the outer surface of said hub,
to thereby connect the guard sleeve to the needle hub.
11. The syringe of claim 9 wherein said needle hub includes radially
outwardly projecting thread means in threaded engagement with said
internally threaded tip sleeve, said thread means on said hub being
axially spaced from the teeth of said guard sleeve inner section.
12. The assembly of claim 10 wherein said needle hub has an upper
section of a first external diameter and a lower section of a second
external diameter smaller than said first external diameter, said
guard sleeve inner section including a body portion having an inner
diameter larger than said second external diameter of said lower
hub section, thereby defining an annular space between said lower
hub section and said guard sleeve body portion, and a cannula cap
having an open end inserted in said annular space and frictionally
secured to said lower hub section.
13. The syringe of claim 9 including a separate attachable protective
cork comprising a cork body having an upper end, a substantially
central recess formed in said upper end, the end of said cannula
being received in said recess and penetrating the bottom thereof,
said guard sleeve having an outer section, said cork upper end being
detachably received in said outer section.
14. A protected needle assembly for a hypodermic syringe comprising:
a standard needle assembly having a needle hub of standard configuration,
said hub having an upper section of a first external diameter and
a lower section of a second external diameter smaller than said
first diameter, said hub having a tapered internal bore,
a cannula secured to the hub in communication with the bore,
a radially outwardly projecting circumferential flange on said
upper section, said flange having first and second oppositely disposed
projections adapted to threadedly engage the threaded sleeve of
a syringe leur tip, and
a multi-section telescopic guard sleeve comprising:
an inner guard sleeve section having an inner diameter greater
than the external diameter of said lower hub section, said inner
guard sleeve section having an upper connecting portion with an
internal diameter substantially equal to the external diameter of
said hub upper section, said connecting portion being a tight friction
fit upon said upper hub section, and said inner guard section being
radially spaced from said lower hub section to form an annular space
there between,
a second guard sleeve section slidably and telescopically connected
to said inner section,
a third guard sleeve section slidably and telescopically connected
to said second guard sleeve section, said guard sleeve sections
being telescopically movable between a contracted position in which
all of said guard sleeve sections are positioned adjacent said hub
and inwardly of a major portion of said cannula, and an extended
position in which the outermost one of said guard sleeve sections
extends to a protective position around the end of said cannula,
and
a cannula guard having an enlarged open end connected to the lower
section of said hub and positioned between said lower section and
said inner guard sleeve section.
15. The assembly of claim 14 wherein said upper connecting portion
of said inner guard sleeve has a pair of diametrically opposed radially
outwardly projecting ears for threaded engagement with the internal
threads of a leur tip sleeve of a syringe.
Syringe needle description
BACKGROUND OF THE INVENTION
The present invention relates to hypodermic syringe needle assemblies,
and more particularly concerns a needle assembly that has an improved
protective sleeve to guard against inadvertent contact with the
end of the cannula.
The standard hypodermic syringe includes a barrel and plunger and
a needle assembly having a hub that is readily attachable to and
detachable from an end of the barrel. The needle hub mounts the
cannula, and in the standard needle assembly, a cannula guard cap
is provided that is a hand tight friction fit on the hub. The cannula
cap is removed for use of the syringe, and after use the cap may
be replaced, or the needle may be inserted into a cork to seal the
contents of the syringe. The required handling of the needle assembly
after use, whether by replacing the cannula cap or inserting the
cannula into a cork, exposes the health care worker to the possibility
of accidental needle sticks. With the highly publicized spreading
of blood-borne diseases, dangers of such accidental needle sticks
are becoming of greater concern. The modern health care worker faces
increased risk of contracting life threatening disease through on-the-job
exposure at least partly due to accidental needle sticks.
The increased danger has stimulated increased effort toward providing
needle assembly protection. Different types of protective devices
have been suggested. Many of such devices, however, require some
type of structure that is connected to or mounted upon the barrel
of the syringe itself and remain connected to the barrel during
use and handling of the syringe. This causes significant interference
with the handling and use of the syringe, since the standard, relatively
smooth and relatively small diameter barrel has now become encumbered
with a protective device, which may prevent direct contact of the
operator's fingers with the barrel itself. Other arrangements for
needle protection, recognizing the problem that stems from the location
of protection mounting structure on the syringe barrel, have provided
special needle and guard assemblies requiring specially manufactured
needles which are considerably longer and more costly than the standard
needle assembly.
A widely used standard needle assembly includes a needle hub having
an upper end that is formed with an arrangement for connecting the
hub to an end of the syringe barrel, and having a lower end to which
is fixedly secured the cannula. A standard syringe barrel has an
end formed with what is commonly known as a leur tip. The leur tip
is available in two forms. A leur slip tip is an elongated, slightly
tapered connecting fitting or neck extending from the end of the
barrel and formed integrally therewith. The slip tip taper is a
hand tight friction fit with the interior of the upper section of
the needle assembly hub, which thus can be firmly connected to or
removed from the syringe barrel. In a second form of leur tip, the
tapered connecting fitting or neck remains the same, but is surrounded
by an internally threaded sleeve radially spaced from the slip tip
neck. The standard needle assembly hub includes an upper flange
having a pair of diametrically opposed, radially outwardly extending
ears, which effectively form a pair of thread elements that threadedly
engage the internal threads on the leur tip threaded sleeve. In
this arrangement the needle assembly hub can be threadedly engaged
with the leur tip, and, at the same time, connected to the tip neck
with a tight frictional fit for more firm securement. The widely
used standard needle assembly thus is particularly configured for
use with the widely used leur tip syringe of either configuration.
Therefore, it is important that a needle guard be usable with the
standard needle assembly and the standard leur tip syringe.
Accordingly, it is an object of the present invention to provide
a needle guard that may be used with standard needle assemblies
and syringes and avoids problems of prior devices.
SUMMARY OF THE INVENTION
In carrying out principles of the present invention, in accordance
with a preferred embodiment thereof, a protective sleeve is made
for use with a needle assembly, which assembly has a hub for connection
to a syringe barrel and a cannula on a lower section. The sleeve
has an inner end secured to and circumscribing an upper section
of the hub, and has an outer end extending to the tip of the cannula
when the sleeve is longitudinally extended. The sleeve is longitudinally
collapsible to a contracted position in which the sleeve outer end
is positioned inwardly of the cannula tip to expose the cannula
tip for use. The sleeve is mounted to the needle assembly of the
standard needle, and does not rely on any connection to the syringe
barrel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a standard syringe and needle assembly with a cannula
cap;
FIG. 2 illustrates the assembly of FIG. 1 with the protective sleeve
of the present invention secured thereto in extended position;
FIG. 3 is an enlarged sectional view of part of the syringe, needle,
assembly and protective sleeve, with the sleeve extended;
FIG. 4 shows the parts of FIG. 3 with the cannula cap removed and
the sleeve contracted;
FIG. 5 illustrates the application of a cannula protecting cork
to a cannula having the protective sleeve secured thereto; and
FIG. 6 is a top plan view of the protective sleeve.
DETAILED DESCRIPTION OF THE INVENTION
A common form of hypodermic syringe together with a standard needle
assembly is illustrated in FIG. 1. The syringe is formed with a
tubular barrel 10 in which is slidably mounted a handle 12 having
a plunger 14 (see FIGS. 3 and 5) at a lower end thereof forming
a slidable but sealing fit within the interior of the barrel. The
end of the barrel includes a leur tip generally indicated at 16
to which is connected a standard needle assembly including a needle
hub 18 having a cannula 20 secured thereto. A cannula cap 22 protects
the cannula tip and is a hand tight friction fit on a lower portion
of the hub 18.
FIG. 2 illustrates the assembly of FIG. 1 having the telescoping
needle guard of the present invention secured thereto. The needle
guard 24 is formed of three telescoping sections comprising an inner
section 30 an intermediate section 32 and an outer end section
34. The inner section is secured to an upper portion of the needle
assembly hub 18 above the upper end of the cannula cap 22.
As shown in the enlarged detailed drawing of FIG. 3 the standard
leur tip includes a leur tip neck 36 formed integrally with the
bottom of barrel 10 and providing a tapered connection fitting for
communicating with and secure attachment to the interior of the
needle assembly hub 18. The hub has a bore with a tapered surface
40 that mates with the outer surface of the leur tip neck 36 and
may be a hand tight fit on the neck to securely hold the needle
assembly on the leur tip neck. In one form of leur tip (not shown),
the tip has only the neck 36. The tight frictional fit between the
neck and hub bore is sufficient, of itself, to secure the needle
assembly to the syringe barrel. In the form of leur tip shown in
the drawings the neck 36 is surrounded by a short cylindrical sleeve
42 that extends from the barrel a distance less than the distance
for which the neck extends. The sleeve 42 has a relatively high
pitch internal thread 44 formed to cooperate with a pair of oppositely
disposed radially outwardly projecting ears 4650 formed on an upper
flange 54 of the upper portion of the needle assembly hub. Thus
by inserting the leur tip neck 36 into the bore 40 and turning the
hub 18 the teeth or ears 4650 become threadedly engaged with the
internal threads 44 and further draw the needle hub further up
onto the leur tip neck to more tightly hold the needle assembly
in its secured position with the syringe barrel.
The standard needle assembly hub includes a relatively larger exterior
diameter upper section 58 and a slightly smaller exterior diameter
lower section 60 that circumscribes the lower portion of the hub
bore 40. To the lowermost end of the hub 18 is secured the cannula
20 having an insertion tip 64. Commonly a cannula cap 22 is provided
in the form of a tapered tube closed at an end adjacent the insertion
tip and open at its upper end. The upper end of the cannula cap
has an enlarged flange 68 circumscribing a cap opening that is a
hand tight friction fit on the smaller diameter lower section 60
of the needle assembly hub.
The telescoping guard sleeve or protective sleeve 24 of the present
invention includes the inner section 30 having a necked down connecting
section 70 at its uppermost end. The necked down connecting section
70 defines an interior bore of a diameter smaller than the interior
diameter of the remainder of section 30. The bore of connecting
section 70 is a hand tight friction fit on the larger diameter upper
section 58 of the hub. Connecting section 70 is formed at its uppermost
end with a pair of diametrically opposed radially outwardly projecting
ears 7476 (FIG. 6), which threadedly engage the internal threads
44 of the threaded leur tip sleeve 42. The ears 7476 of the guard
sleeve connecting section are spaced from the ears 4650 of the
hub assembly when the guard sleeve is assembled on the hub so that
both pairs of ears may engage the inner threads of the leur tip
threaded sleeve.
The lower portion of the inner section 30 of the guard sleeve has
an interior diameter that is larger than the outer diameter of the
lower section 60 of the hub, and thus provides an annular space
for reception of the enlarged inner end 58 of the cannula cap.
Intermediate sleeve 32 of the guard sleeve has an inwardly projecting
small annular flange 80 that circumscribes its periphery and is
a snug, sliding fit on the exterior surface of the lower portion
of inner sleeve section 30. Inner sleeve section 30 is formed with
a small radially outwardly extending annular flange 82 at its lower
end that cooperates with flange 80 to retain the intermediate section
in its slidable relation with respect to the inner section 30. The
latter is also formed with a small annular radially outwardly extending
protrusion 84 adjacent connecting section 70 that helps to retain
the intermediate section on the inner section.
The outer end section 34 of the guard sleeve is formed with a radially
inwardly extending small annular flange 86 that is a snug sliding
fit on the exterior surface of intermediate section 32 and cooperates
with a radially outwardly extending small annular flange 88 on the
outer end of intermediate section 32 to keep the intermediate and
outer guard sleeve sections in engagement. Outer end section 34
is also formed with a radially inwardly projecting small annular
flange 92 that helps retain the outer end section 34 on the intermediate
section 32 when the several sections collapse from the extended
position of FIG. 3 to the contracted position of FIG. 4. The sections
of the guard sleeve are made of a suitable plastic, such as polycarbonate.
The sections have sufficient resilience to allow the interengaging
sections of the guard sleeve to be assembled one upon the other
by forcibly distorting the interengaging flanges 8082 8688.
The described needle guard sleeve, with its three sections telescopically
interconnected, is assembled to the needle hub with the cannula
cap removed from the hub. Connecting section 70 of the inner end
of the innermost sleeve section is forced upon and along the upper,
larger diameter hub section 58 and is a strong hand tight fit thereon.
By this means the telescoping guard will remain attached to the
hub during all subsequent operation with the needle assembly. After
attachment of the telescoping sleeve to the hub, the cannula cap
may be inserted into the sleeve to frictionally engage and be secured
to the smaller diameter lower section 60 of the hub, with the upper
open end of the cannula cap being received within the annular space
between the hub lower section and the relatively larger diameter
of the sleeve inner section. Now the combination of needle hub,
cannula, telescopic guard sleeve and cannula cap, may be readily
assembled to the leur tip, whether the tip has solely the leur tip
neck or includes both the leur tip neck and the leur tip threaded
sleeve. The assembly is secured to the leur tip just as if the telescoping
guard sleeve was not attached to the needle assembly hub. Where
the leur tip has no threaded sleeve, the sole connection between
the guarded needle assembly and the syringe is by means of the friction
fit of the tapered leur tip neck within the tapered bore of the
needle assembly hub. Where the syringe has a leur tip which includes
a threaded sleeve, both the needle assembly hub and the inner section
of the telescopic guard sleeve may threadedly engage the leur tip
threads to more firmly secure the protected needle assembly to the
syringe.
With the needle hub, cannula cap, and telescopic guard sleeve attached
to the syringe, the syringe may be used by merely pulling the cannula
cap off the hub and, with fingers on the exterior of the telescopic
guard sleeve, collapsing the latter to the position of FIG. 4. Note
that in this position the sleeve sections are all substantially
registered with one another so that the lowermost or outermost end
of the sleeve outer end section 34 are withdrawn well back of the
insertion tip of the cannula 62. The ends of all sleeve sections
all are relatively close to a common plane that is perpendicular
to the cannula and close to the hub. In this collapsed position
of the guard sleeve, all but a small upper or innermost portion
of the cannula itself is completely exposed. Further, the guard
sleeve, being attached solely to the needle hub, is itself entirely
below the bottom of the syringe barrel, and thus can in no way interfere
with the use of the syringe by the operator, who normally holds
the syringe by the barrel itself.
With the guard sleeve contracted, and the cannula cap removed,
the insertion tip of the cannula is inserted into a vein or artery
to withdraw blood through the needle hub and through the leur tip
neck into the bottom of the barrel by retracting the plunger 14
of the syringe in standard fashion. After completion of this procedure,
the cannula is withdrawn from the vein or artery, and the syringe
and its needle assembly may be handled in one of several different
ways to seal the syringe interior and protect against accidental
needle sticks by the cannula. In one type of operation the cannula
cap is returned to its place on the lower section of the hub, to
thus protect the cannula. During this operation, the operator previously
was subject to accident needle prick, if the narrow opening of the
cannula guard should miss the cannula tip. However, with the guard
sleeve of the present invention secured to the needle assembly hub,
as described, immediately upon withdrawal of the needle from the
vein or artery the previously contracted guard sleeve sections are
extended so that the outermost sleeve end section extends to or
slightly beyond the end of the insertion tip of the cannula. With
the needle guard extended there is considerably less likelihood
of an accidental needle stick when the cannula cap is returned to
the hub. Further, with the needle guard extended, the insertion
tip is well protected, even in the absence of the cannula cap. It
may not be necessary to return the cannula cap to the hub, thus
further ensuring against accidental needle stick which may occur
during return of the cannula cap.
As mentioned above, with the guard sleeve extended, the insertion
tip of the cannula is protected, with or without a cannula cap.
Moreover, with the guard sleeve extended, the insertion tip of the
cannula (without the cannula cap) may still be inserted into a conventional
needle sealing cork, as illustrated in FIG. 5. Such a conventional
needle sealing cork includes a solid body of a resilient, generally
plastic material 96 having a central relatively shallow depression
98 into which the insertion tip of the cannula may be inserted to
seal the interior of the syringe barrel. The standard cork is generally
formed with a second radially outwardly positioned annular depression
100 which is somewhat deeper than the shallow central depression
98 so that the cork may be fixed to the standard leur tip threaded
sleeve to protect the syringe tip before the needle assembly is
attached to the syringe. For use with the present invention, a cork
96 is provided, but with the outer annular recess 100 made of a
slightly larger diameter to receive the outer end portions of the
outer end section 34 of the telescopically extended guard sleeve.
Thus, after withdrawing the cannula from the vein or artery and
telescopically extending the guard sleeve, the cork may be applied
to the assembly by inserting the cannula insertion tip into a central
portion of the shallow recess 98 causing the insertion tip to puncture
the cork and to be inserted into the body of the cork. At the same
time the outer end section 34 of the guard sleeve is inserted into
the annular recess 100 of the cork, and thus the syringe and needle
assembly are properly sealed with the cannula fully protected.
It will be seen that there has been described a significantly improved
syringe needle guard sleeve. The guard sleeve is useful with the
standard needle assembly, is attached solely to the hub of the standard
needle assembly, and has no portion thereof extending along or around
the syringe barrel. When retracted for use, the guard sleeve in
no way impedes normal use of the syringe. When extended, the guard
sleeve protects against needle sticks and still enables the use
of the standard cannula cap or a cork for sealing the needle end
and connecting to the extended needle guard sleeve. No special needle
or needle construction is required, nor does this guard sleeve in
any way restrict or obstruct handling of the syringe barrel.
The foregoing detailed description is to be clearly understood
as given by way of illustration and example only, the spirit and
scope of this invention being limited solely by the appended claims. |