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Description  |
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The present invention relates to syringe constructions and, more
particularly, to a syringe device which may be used for substance-mixing
purposes in the manner hereinafter pointed out.
In many types of phsiological endeavors, such as sampling, laboratory
testing, culturing, and so forth, in both human and also veterinary
fields, it becomes necessary or appropriate to withdraw a fluid such as
blood into a sterile cavity and to mix the same with another fluid or even
a powdered chemcial, by way of example, previously introduced into the
syringe. All of this needs to be performed under anerobic conditions
within the withdrawal device, i.e. syringe, without the possibility of
introducing contaminants.
The present invention supplies such a mixing syringe, with the same
including plural, concentrically arranged cylindrical bores having
respective pistons. The most forward bore near the canula is of reduced
cross-section, whereas the rearmost bore contiguous therewith is of
enlarged cross-section.
In the invention the foremost piston is keyed to the plunger shaft, whereas
the rearmost piston floats thereon so that the shaft may be withdrawn
rearwardly without disturbing the position of such rearmost piston. The
rearmost piston of course will adjust its disposition on the plunger shaft
in response to any positive fluid pressure existing at its forward
surface.
Accordingly, the forward piston is used to withdraw fluids, such as blood,
from a patient through the cannula and inwardly to the smaller bore area.
Certain bypass apertures are provided which, when unsealed by the foremost
piston, can operate to reduce the degree of negative pressure forwardly of
the forward piston, thereby preserving the integrity of the blood cells
drawn in and also for aiding the further withdrawal of a forward piston
from its bore. A temporary stop or detent means is provided relative to
the forward piston so that one may "feel" when an intermediate extremity
of travel has been reached, thereby enabling the operator to know when a
predetermined amount of fluid has been drawn from a patient.
The device is so constructed such that a further and continued withdrawal
of the forward piston will ultimately produce a loacking, directly, or
indirectly, of the forward piston with the rear piston such that the rear
piston may be urged forwardly with the forward piston upon a return stroke
of the plunger.
The device is suitable for mixing body fluid with a chemical solution or
even with a powder disposed forwardly of the rearmost enlarged piston. The
device can be used in culture, diagnostic, or other procedures, and the
mixing and culturing can take place under anerobic conditions without any
danger whatever of contamination or leakage. The syringe may also be
prefilled with two different solutions that can subsequently be mixed
through plunger withdrawal.
Accordingly, a principal object of the present invention is to provide a
new and improved syringe device usable for mixing purposes as well as for
other uses.
An additional object is to provide a syringe device having multiple or
plural cylinder bores, preferably concentrically disposed, with the
rearmost bore being of the larger crosssectional area, both bores being
provided with respective pistons, the rearmost one being self-adjusting in
response to the presence of fluid pressure.
An additional object is to provide a mixing syringe wherein incoming fluid
can be mixed with a predisposed chemical solution contained centrally
within the syringe.
A further object is to provide a syringe device which is pre-filled with
separate solutions capable of being subsequently mixed at a predetermined
time.
A further object is to provide a device to effect the anerobic storage,
mixture, and culture of solutions of various types.
A further object is to provide a mixing syringe such that any chemical
solution or even dry chemicals will not be mixed with any withdrawn or
incoming fluid prior to the time the syringe is actually withdrawn from
the patient subject and substance mixing is desired.
A further object is to provide a multi-cylinder bore syringe construction
wherein the pistons therein are linked only on forward strokes of the
supplied plunger.
The features of the present invention which are believed to be novel are
set forth with particularity in the appended claims.
The present invention, both as to its organization and manner of operation,
together with further objects and advantages thereof, may best be
understood by reference to the following description, taken in connection
with the accompanying drawings in which:
FIG. 1 is a perspective view of the syringe device of the invention in a
preferred embodiment thereof.
FIG. 2 is a longitudinal, vertical section taken along the line 2--2 in
FIG. 1.
FIG. 3 is similar to FIG. 2 but illustrates the plunger as having been
withdrawn so that the forward piston approaches the rearward piston.
FIG. 4 is an enlarged transverse section taken along the line 4--4 in FIG.
2 and illustrates the configuration of the forward piston and its
engagement with the enlarged head of the plunger shaft.
FIG. 5 is an enlarged, sectional detail taken along the line 5--5 in FIG. 2
and illustrates the prospective passage of the enlarged carrier portion of
the plunger shaft through an eccentrically drilled washer, so that the
shoulder of the carrier portion will assume a thrusting engagement with
such washer preparatory to a forward thrust of both pistons by the
plunger.
FIG. 5A is a section, taken along the line 5A--5A in FIG. 5, illustrating
the configuration of the thrust-like washer and its relationship to the
enlarged carrier portion of the shaft, in accordance with the positioning
in FIG. 5 of such structure.
FIG. 6A is similar to FIG. 5A, is a section taken along the line 6A--6A,
and illustrates the thrust washer and carrier portion in their mutual
relationship when the disposition of the structure shown in FIG. 6 takes
place.
FIGS. 7-10 illustrate in side elevation the operation of the structure
progressively, i.e. in withdrawing fluid from a patient to the mixing
stage, allowing the so-withdrawn fluid to be mixed with any chemicals or
fluid contained within the syringe, and finally, ejecting (FIG. 10) such
mixed fluid through the replaced cannula.
FIGS. 11-13 are similar to FIGS. 7-10 but illustrate a further operating
sequence, hereinafter to be described.
In the drawings, and particularly FIGS. 1 and 2, the syringe device 10 is
shown to include a cylinder housing 11 provided with coaxial, contiguous,
forward and rearward cylindrical bores 12 and 13.
Plunger 14 is provided with an end, thumb-depression knob 15 and also
forward and rear pistons 16 and 17. Plunger at 14 includes an enlarged
head 18, see FIG. 4, which is thrust into a correspondingly shaped
depression 19 in forward, resilient, sealing piston 16. Both pistons have
sealing lands 20-23 for sealing against the interior walls of the
respective cylinder bores.
These pistons are elastomeric and offer a radial compression seal against
the interior bore walls.
A further reason for the elastomeric nature of rear piston 17 is
illustrated in FIGS. 5 and 6. It is noted that such piston is provided
with a conical hollow interior 24 which extends to an annular or circular,
recessed seat 25 that is coaxial with the axis of the piston and of
plunger shaft 26. An annular shoulder 27 is supplied proximate the
terminal aperture 28 of the piston. Element 29 comprises a round washer
having an eccentric aperture 30. Shaft 26 is provided with a concentric,
tapered, enlarged, piston-carrier portion 31. Portion 31, during its
course or rearward travel as the plunger 14 is withdrawn rearwardly, see
FIG. 2, operates to proceed through the aperture 30 and, during such
relative travel, cams upwardly the washer in the direction as shown by
arrow 34, operating upon resilient elastomeric portion 35 of piston 17.
After the carrier portion 31 has proceeded completely through the
aperture, then the elastomeric nature of the piston at 35, see FIG. 6,
operates to provide a restoring force so that such washer portion is
restored downwardly; the thrust shoulder 37 is thereby enabled to press
the washer forwardly and hence urge forwardly the entire piston
construction at 17.
If desired, cylindrical housing 11 may include bypass apertures 38 and 39
for purposes hereinafter described.
Cylindrical housing 11 includes a front opening 40 for receiving the
conventional cannula mount 41, the latter being provided with cannula
needle 42. The rear portion of the cannula at 43 of course will
communicate directly into the opening 40 and may be designed to pierce
diaphragm 44 in the customary manner. The precise cannula construction and
syringe barrel, resilient seal 44, closable upon cannula separation (see
FIG. 10) automatically, are common in the art.
To close the rear of the cylinder housing there is provided a cap 45 that
is screw-threaded onto the threads 46 of cylinder housing 11.
As to the forward cylinder bore 12, the same is co-terminous with an
annular ridge 47 which serves as an abutment ridge to limit temporarily
the rearward travel of forward piston 16.
The operation of the structure as shown in FIGS. 7 thru 13 will now be
described.
Preliminarily, the cannula unit at 41 will be supplied, the rear extremity
thereof pushed through seal 44 so that the tip 48 of the canula
communicates with the interior of cylinder housing 11. The canula needle
42 is thrust into the arm or another part of the body of a patient, for
example, and plunger 14 is withdrawn, see FIG. 8, so that blood will enter
and fill bore 12. The withdrawal of the plunger, in effecting a withdrawal
of the forward piston 16, causes such piston to abut the chamfered stop
ridge 47, see FIG. 8. The stop ridge in fact comprises a measuring detent
so that when the same is reached a predetermined calibrated amount of
fluid will have been drawn to be included within the cavity C in FIG. 8.
As the plunger is further withdrawn, the piston 16 will open the side
passageways 38 and 39. These serve two purposes. First, the same reduces
the negative pressure to the left of the forward piston 16 so as to
preclude a chance of the rupturing of blood cells that have been
withdrawn. Secondly, such negative pressure is reduced, through the fluid
flow, from right to left, through such passageways 38 and 39 thereby
facilitating and easing the further withdrawal of bore piston 16.
It is noted that during this entire operation floating piston 17 will
remain in its predetermined position, see FIGS. 2, 7 and 8, owing to the
slippage of plunger shaft 26 through axial aperture A of FIG. 6. Of
course, piston 17 will be free to adjust in response to positive fluid
pressure that may exist forwardly thereof. The enlargement of carrier
portion 31 will approach progressively the elastomeric piston 17 and
finally pass through the central eccentric aperture 37 of thrust washer
29. This operation will be accompanied by the thrusting outwardly of
washer 29 against portion 36 of the piston 17 in FIG. 6, thereby aiding
the carrier portion 31 to proceed through the washer's eccentric aperture
and proceed therepast to the position shown in FIGS. 6 and 6A and also in
FIG. 10. Accordingly, regardless of the axial or circumferential
orientation of the rod, the abutment will proceed through the washer one
way, but thereafter will be operative, via thrust shoulder 37, to urge the
washer and, thereby, the piston 17 forwardly. It is noted that the washer
is seated in groove 25 in FIG. 5.
Once there has been a withdrawal of piston 16 past bore 12, then the blood
or other body fluid that has been withdrawn and any solution or chemical
(solid) as might be contained in cavity C', see FIG. 8, can be mixed as in
FIG. 10 and subsequently ejected into a test tube, on a test slide, and so
forth.
FIGS. 11-13 illustrate that the same procedure may be followed as that
shown in FIGS. 7 thru 10, but this time, not only can two fluids be mixed,
but also an incoming fluid in conjunction with a chemical mixture
contained in cavity C'. In all other aspects the operation remains the
same. FIGS. 11-13 also illustrate that the syringe may be pre-filled with
separated solutions, and such solutions can be mixed through the simple
withdrawal of the plunger. The solutions may be stored either in their
mixed or separated condition for extended periods of time as for culture
purposes, periodic slide work, and so forth. In connection with prefill
usage, incorporation of the canula may be deleted.
What is thus provided is a multi-cavity syringe wherein the cavities or
cylinder bores are axially oriented. A single plunger shaft is provided
with a pair of pistons, a forward fixed piston and a rear floating piston.
This structure is provided so that with the rearward actuation of the
plunger shaft, the forward piston can be withdrawn as needed, with the
rear piston remaining in a sealed, self-adjusting condition.
After a full withdrawal the two plungers may be linked together to move in
tandem for an expression of contents, subsequent to the intermediate step
of mixing the withdrawn fluid with any fluid or powder or other chemical
disposed within the interior of the syringe prior to initial drawing in of
fluid.
While particular embodiments of the present invention have been shown and
described, it will be obvious to those skilled in the art that changes and
modifications may be made without departing from this invention in its
broader aspects, and, therefore, the aim in the appended claims is to
cover all such changes and modifications as fall within the true spirit
and scope of this invention.
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