Safety syringe abstract
A hypodermic safety syringe, according to the present invention,
includes a barrel having an open end, a cone shaped end and an interior
surface. A hollow needle and carriage assembly is temporarily attached
and is restrained by four catches extending from the interior tapered
surface. A plunger assembly is reciprocally received into the barrel
and is in air-tight engagement with the interior surface of the
barrel. Thus, an interior chamber is formed in the barrel whereby
liquids are retrieved and emitted through the hollow needle. A cavity
within the plunger contains a spring and retraction guide assembly
with a mating member corresponding to mating members extending from
the needle carriage. As the mating members contact and become captured
the needle and carriage assembly is released by the approaching
plunger assembly as the catches are deflected outward by the angled
surface of the plunger. At the end of the injection stroke small
spherical bearings, in locking contact with the retraction guide,
are caused to move outward and into a radially concave interior
surface releasing the retraction guide, captured needle and carriage
assembly thereby retracted into the cavity within the plunger structure.
Thus rendering the syringe safe for handling and transport to disposal.
Safety syringe claims
We claim hereupon:
1. A hypodermic safety syringe with a retracting needle system
comprising;
a transparent cylindrical body element for containing a liquid;
having appurtenances interacting with;
a hollow needle temporarily interconnected with said body element
for communicating liquid between said body element and a patient,
area or process, said needle having a carriage and a hollow tine,
said needle repositionable between an operable extreme wherein said
needle projects axially outward from said body element and an inoperable
extreme whereby said needle is retracted and contained completely
within said body element by interacting with;
a plunger reciprocally received into said body element whereby
vacuum and pressurization forces are generated by adjustment of
said plunger within said body element wherein liquid is drawn into
said body element communicating through said needle by vacuum caused
by adjusting said plunger outward from said body element and wherein
liquid is expelled from said body element communicating through
said needle by pressurization force caused by adjusting said plunger
into said body element;
a retraction mechanism whereby a retraction guide is permanently
connected to a spring and is locking contact with spherical bearings
thus held motionless within a cylindrical cavity within the plunger
structure,
a safing means associated with said hypodermic safety syringe with
retracting needle whereby the needle is automatically retracted
into a cavity within said plunger substantially at the end of the
injection stroke whereby mating members extending from the retraction
guide and needle carriage engage and become captured as an angled
surface on the plunger deflects catches restraining the needle and
carriage assembly; spherical bearings within shafts in the plunger
align with a radial concave interior surface of the barrel thereby
releasing the retraction guide, captured needle and carriage assembly
thereby retracting within the cavity in the plunger structure and
rendering the syringe safe for handling and transport to disposal.
2. The hypodermic safety syringe of claim 1 wherein said needle
and carriage assembly comprise a hollow needle permanently affixed
within a tapered carriage with four radially aligned mating members
adapted to receive, engage and capture an adapted mating member
extending from a retraction guide armed within a plunger.
3. The hypodermic safety syringe of claim 2 wherein said plunger
further consists of a front section containing latitudinal bores
for receiving spherical bearings whereby a retraction guide is caused
to be in locking contact with said bearings and restrained by force
of a spring; said plunger further containing a cylindrical cavity
adapted to receive said needle and carriage assembly upon retraction
this being facilitated by weep holes in the cylindrical cavity providing
a means to exhaust air trapped within the cavity whereby said air
is emitted into a space between the plunger and barrel.
4. The hypodermic safety syringe of claim 3 whereby said retraction
guide having a protruding mating surface adapts to engage and capture
said needle and carriage assembly; said retraction guide having
radially concave surfacing thereby permitting said spherical bearings
to encroach upon and render locked said retraction guide.
5. The hypodermic safety needle of claim 4 whereby said spring
is permanently mated to said retraction guide and permanently mated
to a circular cap affixed to the open end of the cylindrical cavity
adapted to receive and restrain the circular cap; said spring providing
a biasing means for restraining the retraction guide assisted through
static position of said spherical bearings thereby providing a biasing
means retracting the retraction guide and captured needle and carriage
assembly automatically as the injection stroke achieves finality;
thereby rendering the syringe safe for handling and transport to
disposal.
6. The hypodermic safety syringe of claim 5 whereby said plunger
having longitudinal ribs with notches substantially adapted to fit
snugly about an insert guide restrained at the open end of the barrel
whereby said plunger can be caused to be rendered axially locked
prior to and after use of said syringe.
7. The hypodermic safety syringe of claim 6 further comprising
a protective cover adapted to contain within, a portion of, said
needle protruding from said barrel and further adapted to be detachably
attached to said barrel.
8. The hypodermic safety syringe of claim 7 further comprising
a graphic scale embossed upon the exterior surface of said barrel,
accounting for internal volume losses and providing for measurability
of volumes of liquid contained within the cylindrical chamber; said
graphic scale units of measurement corresponding to particular industry
requirements.
9. The hypodermic safety syringe of claim 1 whereby said cylindrical
cavity is caused to contain a sufficient vacuum force acting on
said retraction guide in a manner as a biasing means; thereby providing
a force acting in conjunction with said spherical bearings whereby
said retraction guide is locked motionless and automatically retracting
the retraction guide and captured needle and carriage assembly as
the injection stroke reaches finality; thereby rendering the syringe
safe for handling and transport to disposal.
Safety syringe description
BACKGROUND OF THE INVENTION
This invention relates to medical and industrial devices used for
administering or receiving fluids to or from a patient, area or
process and more specifically to a hypodermic syringe with a mechanical
system for automatically retracting the needle into the syringe,
thereby rendering the syringe useless and safe for handling and
transport to disposal.
Current designs for monouse syringes do not allow for the inadvertent
or accidental puncture of health care, laboratory and industrial
users who come in contact with an exposed needle. Monouse syringes
can be used as many times as desired despite labeling and warnings
to the contrary. Furthermore, current patented designs for retractable
needle type syringes are at best poor in their solutions to the
problem of conveying or retracting the needle from the operational
condition to a protected or enclosed condition. Some even fail to
address covering the needle prior to use. U.S. Pat. No. 4838869
to Allard and U.S. Pat. No. 4955870 to Ridderheim et al. disclose
a means whereby the needle assembly acting as a piston is retracted
aft by a spring under tension into a cylindrical chamber within
the structure of the plunger and illustrates no means to prevent
the pressurization of air trapped in the chamber by the rapidly
retracting needle assembly. Clearly, this would miss a basic mechanical
need to provide for venting the cylinder to allow air trapped in
the cylinder to escape.
These and other weaknesses in the current art designs coupled with
economic considerations for manufacture may not permit a viable
solution to be available in the market for some years to come. The
incidence of injury to life and health by accidental puncture and
cross contamination of persons using, handling, or in close proximity
to syringes having exposed contaminated needles is greater now than
ever before. The need for a safe, reliable, inexpensive, and manufacturable
retracting needle syringe is of significant importance.
SUMMARY OF THE INVENTION
The present invention provides a solution to the above-mentioned
needs while overcoming the shortcomings of the prior art by providing
a simplified approach to design problems in a syringe with a retractable
needle. The retractable needle system in this embodiment uses five
moving part assemblies including the plunger movement and provides
classic mechanical solutions for the restraining, triggering and
retracting operations of the needle. The absence of shearable materials
or special minute fabrications provides reliability and economy
in the manufacture and use of the syringe.
The hypodermic syringe, according to the present invention, includes
a barrel having an open end, a cone shaped end with a small orifice,
and an interior surface. The small orifice at the coned end of the
barrel is of sufficient interior diameter to allow unrestricted
passage of a hollow needle mated into a carriage fitting snugly
into a tapered interior surface at the coned end of the barrel.
The needle carriage is restrained mechanically by four catches extending
from the interior tapered surface at the coned end of the barrel
with each having a raised lip extending over the larger end of the
tapered needle carriage. A plunger assembly is reciprocally received
into the barrel at the open end and is in an air-tight engagement
with the interior surface of the barrel. The engagement between
the plunger and the barrel allows for axial and radial adjustment
of the plunger. Thus, providing a variable cylindrical chamber formed
between the inserted end of the plunger and the interior surfaces
of the barrel. The chamber receives and emits liquids communicating
through a hollow needle by hydraulic action resulting from axial
adjustments between the plunger and barrel. The plunger structure
includes a concentric cylindrically shaped cavity extending axially
from one end to the other, wherein an assembly comprised of a cap,
a spring and a retraction guide is received. The cap adapts to the
cylindrical cavity in the plunger at the end of the plunger protruding
from the barrel and is permanently restrained by radial concavities
binding aligned radial convexities extending from the interior surface
of the barrel. A biasing means or spring is attached into the surface
of the cap extending into the cylindrical cavity at one end and
attached to a retraction guide at the other. The retraction guide,
with radially concave surfaces, allows spherical bearings present
in adjacent latitudinal shafts extending from either interior surface
of the barrel to extend into the radially concave surfaces and temporarily
lock the retraction guide into a fixed position. The position of
the retraction guide at the inserted end of the plunger renders
the spring extended and under stress. The retraction guide incorporates
a means to capture the needle and carriage assembly using a convex
mating member that attaches to adapted mating members protruding
from the needle carriage when the plunger approaches the coned end
of the barrel.
To begin operation, a protective cover about the needle is removed.
The exposed portion of the plunger is rotated in either direction
to align the longitudinal ribs of the plunger body with the openings
in the insert at the open end of the syringe. The needle is placed
into a area or process where a desired volume of available liquid
may be withdrawn through the needle and into the cylindrical chamber
by adjusting the plunger outward and away from the coned end of
the barrel. The needle may then be reinserted into a patient area
or process and the collected liquid injected into same by adjusting
the plunger into and towards the coned end of the barrel. As the
plunger approaches the end of the injection stroke a convex mating
member extending from the retraction guide inserts and captures
mating members extending from the needle carriage. Substantially
toward the end of the injection stroke an angled circular surface
at the mating end of the plunger comes in contact with four catches
extending from the interior tapered surface at the coned end of
the barrel. As the plunger continues, the catches are caused to
be deflected outward and away from the centerline of the syringe
and raised surfaces previously restraining the needle carriage are
cleared. As the injection stroke finalizes, spherical bearings restraining
a retraction guide align with a radial concave interior surface
allowing force acting on the bearings to cause them to be repositioned
outward and away from the centerline of the barrel. Thus, releasing
the retraction guide coupled with the needle and carriage for retraction
into the cylindrical cavity in the plunger by the biasing means
or spring. Accordingly, the contaminated needle is contained within
the structure of the syringe and renders the syringe unusable and
safe for handling and transport to disposal.
In one embodiment, a hypodermic syringe, as summarized herein,
uses a alternate biasing means to retract the retraction guide,
captured needle and carriage into the cylindrical cavity. The concentric
cylindrical shaped cavity within the structure of the plunger is
caused to contain a sufficient vacuum force to retract the retraction
guide, captured needle and carriage. Thereby, effectively eliminating
a need for a spring mechanism.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings will serve to further clarify the present invention.
Referencing the following description of embodiments of this invention
taken in conjunction with the accompanying drawings wherein:
FIG. 1 is an axial section through the syringe according to the
present invention with the plunger partially withdrawn and the protective
cover about the hollow needle removed for clarity;
FIG. 2 is an axial section through the syringe provided at a scale
that is 81.8416% the size of FIG. 1 and is of identical scale with
the remaining figures. FIG. 2 serves as a reference to sections
taken radially at locations along the syringe;
FIG. 3 is a section taken at line FIG. 3--FIG. 3 of FIG. 2;
FIG. 4 is a section taken at line FIG. 4--FIG. 4 of FIG. 2;
FIG. 5 is a section taken at line FIG. 5--FIG. 5 of FIG. 2;
FIG. 6 is a section taken at line FIG. 6--FIG. 6 of FIG. 2;
FIG. 7 is an exploded view of the barrel assembly parts in relative
positions required for their assembly;
FIG. 8 is an exploded view of the plunger assembly parts in relative
positions required for their assembly;
FIG. 9 is an axial section through the syringe according to the
invention in its initial state as provided by manufacture including
a protective cover over a protruding needle and prepared for use;
FIG. 10 is an axial section through the syringe according to the
invention showing the syringe of FIG. 9 with the plunger adjusted
to an intermediate location away from the coned end of the barrel.
FIG. 10 serves to illustrate a hypodermic syringe approximately
25% loaded with liquid;
FIG. 11 is an axial section through the syringe according to the
invention showing the syringe of FIG. 9 with the plunger fully inserted,
the needle and carriage and retraction guide released. The retraction
guide is shown in motion towards the interior of the cylindrical
cavity in the plunger structure; and
FIG. 12 is an axial section through the syringe according to the
invention showing the syringe of FIG. 9 after use with the needle
and carriage retracted.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1 3-8 a syringe according to the present invention
consists of an assembly, subassemblies, and parts wherein numerals
and alpha characters are assigned to the various parts, part features
and part assemblies for referencing like elements throughout the
drawings. Numerals are assigned to a part, similar part and/or part
assembly, where alpha characters are significant of sub-parts of
assemblies and/or sequencing of part features. The syringe consists
of a barrel (1a) having an open end, a coned end with an axial needle
receiving bore, and a substantially smooth cylindrically shaped
interior surface. A semi-circular grip (1d) an integral part of
the barrel (1a) is provided to be gripped with the index and middle
fingers of the user while applying pressure to the cap (3d) of the
plunger subassembly (3a)-(3d) with the thumb of the same hand during
the injection stroke. A radial bulge (1b) provides a concave surface
within the interior of the barrel (1a) sized to accept spherical
bearings (2b) forced out of latitudinal shafts at the inserted end
of the plunger (2a) as it completes the injection stroke. Four radially
spaced resilient catches (1c) cause the needle and carriage subassembly
(4a)-(4c) to become restrained as raised surfaces of the catches
(1c) encroach over the larger end of the needle carriage (4b). A
protective cover (6) is placed over the needle and snapped into
place using radial concavities and convexities aligned on the interior
of the open end of the protective cover (6) and the exterior of
the coned end of the barrel (1a) respectively. Thus, the barrel
subassembly (1a)-(1d), (4a)-(4c), (6) is prepared to accept the
plunger subassembly (2a)-(2f), (3a)-(3d), (5).
FIG. 8 illustrates the parts incorporated in the plunger subassembly.
O-ring seals (2c) and (2d) are placed over the inserted end of the
plunger (2a) and into radial concave grooves at the inserted end
of the plunger (2a). Four spherical bearings (2b) are inserted into
latitudinal shafts extending through the inserted end of the plunger
(2a). At the other end of the plunger (2a) an opening in an insert
(5), loosely corresponding to the cross sectional geometry of the
plunger cavity and ribs (2a), is aligned and passed over the plunger
(2a) body to a point aligning with notches (2f) in the ribs of the
plunger (2a) structure. The insert (5) is then rotated 45 degrees
about the plunger (2a) in either direction, thus locking the insert
(5) within the notches (2f). A retraction guide subassembly (3a)-(3d)
is fitted with a flat circular seal (3b) over the retraction guide
(3a) and snug to a raised circular surface at a point where an integral
circular block contains a spring (3c) previously affixed by permanent
means. A circular cap (3d) previously affixed to the other end of
the spring (3c) by permanent means completes the retraction guide
subassembly (3a)-(3d). The retraction guide (3a) end of the retraction
guide subassembly (3a)-(3d) is reciprocally received into the concentric
circular cavity in the plunger (2a) structure at the end of the
plunger (2a) having weep holes (2e), and snapped into place using
radial concavities and convexities aligned on the exterior of a
raised circular surface containing the spring (3c) of the circular
cap (3d) and interior of the weep hole (2e) end of the plunger (2a),
respectively. The final preparation of the plunger subassembly (2a)-(2f),
(3a)-(3d), (5) requires an external biasing means to transport the
retraction guide (3a) towards the insertion end of the plunger to
a point where spherical bearings (2b) are moved into locking contact
with the radial concave surfaces of the retraction guide (3a) and
held in such a state by external means. Thus, the plunger subassembly
(2a)-(2f), (3a)-(3d), (5) is prepared to be assembled with the barrel
subassembly (1a)-(1d), (4a)-(4c), (6).
The plunger subassembly (2a)-(2f), (3a)-(3d), (5) is reciprocally
received into the barrel subassembly (1a)-(1d), (4a)-(4c), (6) and
inserted to a point where the insert (5) is snapped into place using
radial concavities and convexities aligned on the radial surface
of the insert (5) and the interior of the open end of the barrel
(1a), respectively. Thus, the syringe is assembled in an embodiment
represented by FIG. 9. Referring to FIG. 1 7 and 8 FIG. 9 represents
the syringe in its initial state, prepared for use with the plunger
subassembly (2a)-(2f), (3a)-(3d), (5) rendered immovable in either
axial direction by notches in the ribs of the plunger (1a) structure
misaligned with the opening in the insert (5). The hollow needle
(4a) is protected and caused to be contained using a cylindrical
cover (6). The retraction system is in an armed condition resulting
from the above-mentioned assembly process. The hypodermic syringe,
according to the invention is put into service by removal of the
protective cover (6) exposing the hollow needle (4a) and rotating
the circular cap (3d) approximately 45 degrees or until the ribs
of the plunger (1a) structure are caused to become aligned with
a corresponding opening in the radial plane of the insert (5) allowing
the plunger assembly (2a)-(2f), (3a)-(3d) to be adjusted axially.
Thus, the syringe is prepared for loading. The loading of the syringe
is commenced by inserting the hollow needle (4a) into an area or
process to a point engaging a liquid source and pulling the plunger
assembly (2a)-(2f), (3a)-(3d) by grasping the circular cap (3d )
and pulling in one direction while concurrently pulling the barrel
(1a) in an opposite direction, thereby adjusting the location of
the plunger assembly (2a)-(2f), (3a)-(3d) within the barrel (1a).
Thus, causing source liquid to be drawn through the hollow needle
(4a) as a result of a vacuum caused by the increasing geometry of
the cylindrical chamber formed by the interior surfaces of the barrel
(1a) and the inserted end of the plunger assembly (2a)-(2f), (3a)-(3d).
FIG. 10 serves to illustrate the loaded condition showing a plunger
assembly (2a)-(2f), (3a)-(3d) adjusted to approximately 25% of full
capacity. The syringe is now reinserted into a patient, area or
process and an injection stroke is initiated by grasping the tabs
(1d) with the index and middle finger straddled about the barrel
(1a) body and applying pressure with the thumb of the same hand
to the circular cap (3d). As the area in the cylindrical chamber
containing liquid is caused to decrease the liquid is pressurized
and escapes by communicating through the hollow needle and effectively
into the patient, area or process so selected. As the plunger assembly
(2a)-(2f), (3a)-(3d) approaches the end of the injection stroke
a convex mating member extending from the retraction guide (3a)
inserts and captures four mating members (4c) extending from the
needle carriage (4b). Substantially toward the end of the injection
stroke FIG. 11 an angled circular surface at the inserted or mating
end of the plunger (2a) comes in contact with four catches (1c).
As the injection stroke continues, the catches (1c) are caused to
be deflected outward by angular forces being applied by the contacting
surfaces of the plunger (2a). Raised surfaces previously restraining
the needle carriage (4b) are cleared, thus, releasing the needle
carriage subassembly (4a)-(4c). As the injection stroke finalizes,
spherical bearings (2b) in locking contact with the retraction guide,
(3a) align with a radial concave interior surface (1b) allowing
force acting on the spherical bearings (2b) to transmit them outward
and away from the centerline of the syringe and into the radial
concave surface (1b ). Thus releasing the retraction guide (3a)
mated with the needle and carriage subassembly (4a)-(4c) to be retracted
into the cylindrical cavity within the structure of the plunger
(2a) by a biasing means or spring coming into mechanical equilibrium.
Weep holes, (2e) in the cylindrical cavity of the plunger, (2a)
facilitates evacuation of air trapped in the cavity as the retraction
guide (3a) retreats into the cavity thereby displacing air into
and out of the area between the barrel (1a) and the plunger (2a)
body. Holes in the radial plane of the insert, (5) at the open end
of the barrel, (1a) provide further relief of air both in the adjustment
of the plunger assembly (2a)-(2f), (3a)-(3d) and the displacement
of air by movement of the retraction guide (3a).
FIG. 12 illustrates the final state of the syringe according to
the present invention. The contaminated hollow needle (4a) is caused
to be contained within the cylindrical cavity and caused to be harmless,
useless and safe for handling and transport to disposal means.
While these embodiments of a hypodermic syringe as described herein
are designed interrelatedly to themselves it will be understood
the syringe is capable of adjustments and modifications to the system
for ergonomic, economic, functional and aesthetic reasons. This
application is, therefore, intended to specifically cover any variations,
modifications, adjustments, uses or adaptations of the invention. |