U.S. patent number 3,927,955 [Application Number 05/377,677] was granted by the patent office on 1975-12-23 for medical cassette pump.
This patent grant is currently assigned to East/West Medical Products, Inc.. Invention is credited to Dominic Spinosa, John Varga.
United States Patent |
3,927,955 |
Spinosa , et al. |
December 23, 1975 |
Medical cassette pump
Abstract
A medical cassette pump is provided, especially adapted for
acting upon disposable fluid-carrying tubing in a manner such that
the tubing can easily be inserted and removed from the
fluid-pumping assembly. The pump includes a drive motor which
rotates a fluid-pumping assembly about a principal axis. The fluid
pumping assembly including pumping means engaging the
fluid-carrying tube and advancing fluid along the tube in response
to rotation of the fluid-pumping assembly, and displaceable
cassette means for releasably engaging the fluid-carrying tube
against the pumping means.
Inventors: |
Spinosa; Dominic (Wantagh,
NY), Varga; John (Bayville, NY) |
Assignee: |
East/West Medical Products,
Inc. (Hauppauge, NY)
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Family
ID: |
26869789 |
Appl.
No.: |
05/377,677 |
Filed: |
July 9, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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174019 |
Aug 23, 1971 |
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Current U.S.
Class: |
417/477.3;
417/477.11 |
Current CPC
Class: |
A61M
60/279 (20210101); F04B 43/1253 (20130101); A61M
5/142 (20130101) |
Current International
Class: |
A61M
5/142 (20060101); F04B 43/12 (20060101); F04B
043/08 (); F04B 043/12 (); F04B 045/26 () |
Field of
Search: |
;417/474,475,476,477 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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438,536 |
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Aug 1948 |
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IT |
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569,684 |
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Aug 1958 |
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BE |
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Primary Examiner: Freeh; William L.
Assistant Examiner: Gluck; Richard E.
Parent Case Text
This application is a continuation-in-part of Ser. No. 174,019,
filed Aug. 23, 1971, and now abandoned.
Claims
Having regard to the foregoing disclosure the following is claimed
as the inventive and patentable embodiments thereof:
1. A medical cassette pump comprising in combination a driving
means; a fluid-pumping assembly operatively coupled to the drive
means for rotation thereby about a principal axis, said
fluid-pumping assembly including a pumping means rotatable about
the principal axis; cassette means movable between a first position
towards and a second position away from the pumping means; means
defining at least one wall of a channel for reception of a
fluid-carrying tube; the wall restraining the tube from movement
away from the pumping means and retaining the tube in a path
corresponding to the rotational path of the pumping means in close
proximity to the pumping means in a manner such that the tube is
collapsed by the pumping means against the wall; the cassette means
in the first position retaining the fluid-carrying tube in the
channel and in a position to be collapsed by the pumping means, and
in the second position releasing the tube from such engagement to
permit insertion of the tube in the channel or removal of the tube
from the channel, and the pumping means in said first position of
the cassette means being always in engagement with the tube at some
portion along the tube for pumping of fluid through the tube upon
rotation of the drive means; said cassette means comprising a pair
of cassette half-members each describing an approximately
180.degree. arc and pivotably mounted at one end in a manner such
that, when brought together, they extend through an approximately
360.degree. arc about the fluid-pumping drive assembly and having
an inside wall defining one wall of the channel.
2. A medical cassette pump according to claim 1 in which the
cassette means comprises a plurality of cassette members each
describing a segment of the arc of an approximately circular shape,
and mounted for relative pivotable movement towards and away from
the pumping means.
3. A medical cassette pump according to claim 1 in which the
cassette means comprises a disc pivotably mounted at one side with
the channel extending about one side of the disc, and enclosing the
circular path followed by the pumping means.
4. A medical cassette pump according to claim 1 in which the
pumping means is coupled to the drive means for rotation thereby
about its axis, in an arc corresponding to the arc of the channel,
and in close proximity thereto, spaced therefrom by a distance
equal only to the diameter of a fluid-carrying tube when collapsed
and therefore closed off by the pumping means against the channel
restraining wall, so that where the pumping means engages the tube,
it closes off the tube to fluid flow against the interior wall of
the cassette means, and by its rotation about the principal axis
advances the fluid along the tube in response to the rotation of
the fluid drive assembly.
5. A medical cassette pump according to claim 1 comprising a frame
with the cassette means releasably mounted on the frame, for
simultaneous removal of the cassette and fluid-carrying tube.
6. A medical cassette pump according to claim 1 in which the
channel is attached to the cassette means.
7. A medical cassette pump comprising in combination a driving
means; a fluid-pumping assembly operatively coupled to the drive
means for rotation thereby about a principal axis, said
fluidpumping assembly including a pumping means rotatable about the
principal axis; cassette means movable between a first position
towards and a second position away from the pumping means; said
pumping means defining at least one wall of a channel for reception
of a fluid-carrying tube, the wall restraining the tube from
movement away from the cassette means and retaining the tube in a
path corresponding to the rotational path of the pumping means in
close proximity to the pumping means in a manner such that the tube
is collapsed by the cassette means against the wall; the cassette
means in the first position retaining the fluid-carrying tube in
the channel and in a position to be collapsed by the pumping means,
and in the second position releasing the tube from such engagement
to permit insertion of the tube in the channel or removal of the
tube from the channel, and the pumping means in said first position
of the cassette means being always in engagement with the tube at
some portion along the tube for pumping of fluid through the tube
upon rotation of the drive means; said cassette means comprising a
pair of cassette half-members each describing an approximately
180.degree. arc and pivotably mounted at one end in a manner such
that, when brought together, they extend through an approximately
360.degree. arc about the fluid-pumping drive assembly, said
pumping means comprises grooved rollers, with the channel being the
groove and the restraining wall thereof an internal peripheral wall
of the cassette means.
8. A medical cassette pump according to claim 1 in which the
cassette means is formed with at least one opening therethrough in
communication with the channel for passage of the fluidcarrying
tube to the channel.
9. A medical cassette pump according to claim 1 in which the
cassette means is pivotably mounted on a shaft and having bias
means for biasing the cassette means in the first position, holding
the fluid-carrying tube in engagement with the pumping means.
10. A medical cassette pump according to claim 1 comprising a
switch operatively coupled to the drive means and means engaging
the switch.
11. A medical cassette pump according to claim 4 in which there is
one pumping means in continuous engagement with one portion of the
fluid-carrying tube.
12. A medical cassette pump according to claim 1 in which the
channel defines a loop extending over an arc that is less than
360.degree..
13. A medical cassette pump according to claim 12 in which there
are at least two pumping means, of which at least one is always in
engagement with a portion of the loop.
14. A medical cassette pump according to claim 1 in which the
pumping means is a roller mounted for free rotation on a shaft
attached for rotation about the principal axis.
15. A medical cassette pump comprising drive means; a fluid-pumping
assembly operatively coupled to said drive means for rotation
thereby about a principal axis, said fluid-pumping assembly
including at least two planetary rollers freely rotatably mounted
in spaced relation to said principal axis to each other; a
fluid-carrying tube; and displaceable cassette means for releasably
engaging said fluid-carrying tube against at least one of said
planetary rollers for the displacement of said fluid therealong,
said cassette means including a pair of cassette half-members
hingedly joined at one end thereof for relative pivotal
displacement toward and away from said principal axis, said
cassette half-members being formed so as to define a central
opening for receiving said fluid-pumping assembly when said
cassette half-members are joined together, at least a portion of
the inner periphery of said cassette half-members defining said
central opening being formed with a channel facing said principal
axis for receiving a portion of said fluid-carrying tube and for
crimping said tube substantially closed against at least one of
said planetary rollers when said cassette half-members are
joined.
16. A medical cassette pump according to claim 15 wherein said
channel has an inner wall, said planetary rollers being dimensioned
to extend into said channel with said fluidcarrying tube crimped
between said channel inner wall and at least two of said rollers
when said cassette half-members are joined.
17. A medical cassette pump according to claim 15 wherein said
channel is formed with an inner wall, and dimensioned to permit
said portion of said fluid-carrying tube received therein to extend
laterally therefrom while permitting said planetary rollers to
engage said fluid-carrying tube in a substantially closed position
against said channel inner wall when said cassette half-members are
joined.
18. A medical cassette pump according to claim 15 wherein each of
said pair of cassette half-members is formed with a bore
therethrough in a region spaced from the hinge thereof and
providing communication to said channel, each of said bores being
dimensioned to permit the threading of said fluid-carrying tube
therethrough with a portion thereof in said channel.
19. . A medical cassette pump according to claim 15 including frame
means, and spring latch means mounted on said frame means and
positioned to engage each of said cassette half-members for
releasably retaining said cassette half-members joined
together.
20. A medical cassette pump according to claim 15 including a
frame, and latch means mounted on said frame member and releasably
engaging said cassette means for retaining said cassette means
mounted on said frame while permitting the removal therefrom
independent of said fluid-pumping assembly.
21. A medical cassette pump according to claim 15 including at
least two fluid-carrying tubes, each of said cassette half-members
including at least one channel for receiving each of said
fluid-carrying tubes for engaging said fluid-carrying tubes against
at least two of said planetary rollers.
22. A medical cassette pump according to claim 21 wherein said
fluid-pumping assembly includes two sets of said planetary rollers
substantially aligned in two planes spaced along said principal
axis and positioned so that one of said sets of planetary rollers
engages each of said fluid-carrying tubes.
23. A medical cassette pump according to claim 15 wherein the end
of said cassette half-member spaced from said hinge connection
therebetween is formed with a facing slot providing communication
to said channel and dimensioned to receive said fluid-carrying tube
as said cassette half-members are brought together, and to retain
said fluid-carrying tube when said cassette half-members are
joined.
24. A medical cassette pump according to claim 23 including tab
means formed with a pair of apertures therethrough dimensioned to
have said fluid-carrying tube threaded therethrough to define a
loop, said loop being dimensioned to extend about said planetary
rollers for receipt in said cassette half-member channels and said
cassette half-member slots.
25. A medical cassette pump according to claim 15 including tab
means formed with at least a pair of apertures dimensioned to have
said fluid-carrying tube threaded therethrough to define a loop in
said fluid-carrying tube dimensioned to extend about said planetary
rollers, said pump including enabling switch means coupled to said
drive means and adapted to enable the operation of said drive means
when closed, said tab means including a finger dimensioned to
engage said enabling switch means to close same when said loop of
said fluid-carrying tube is properly positioned about said
planetary rollers.
26. A medical cassette pump according to claim 15 wherein said
displaceable cassette means includes a channel for receiving said
fluid-carrying tube threaded therein, said displaceable cassette
means and said fluid-carrying tube being disposable as a unit.
27. A cassette for a medical cassette pump having a drive means; a
fluid-pumping assembly operatively coupled to the drive means for
rotation thereby about a principal axis, and a pumping means
rotatable about the principal axis comprising, in combination,
cassette means for attachment to the pump in a manner to be movable
between a first position towards and a second position away from
the pumping means; means defining at least one wall of a channel
for reception of a fluid-carrying tube, the wall restraining the
tube from movement away from the pumping means, and retaining the
tube in a path corresponding to the rotational path of the pumping
means in close proximity to the pumping means in a manner such that
the tube is collapsed by the pumping means against the wall; the
cassette means in the first position retaining the fluid-carrying
tube in the channel and in a position to be collapsed by the
pumping means and in the second position releasing the tube from
such engagement to permit insertion of the tube in the channel or
removal of the tube from the channel so that the pumping means in
said first position of the cassette means is always in engagement
with the tube at some portion of its length, and moves the
collapsed portion along the tube for pumping of fluid through the
tube upon rotation of the drive means; said cassette means
comprising a pair of cassette half-members each describing an
approximately 180.degree. arc and pivotably mounted at one end in a
manner such that, when brought together, they extend through an
approximately 360.degree. arc about the fluid-pumping drive
assembly and having an inside wall defining one wall of the
channel; bias means for biasing the cassette means in the first
position, holding the fluidcarrying tube in engagement with the
pumping means.
28. A cassette according to claim 27 in which the cassette means
comprises a plurality of cassette members each describing a segment
of the arc of an approximately circular shape.
29. A cassette according to claim 27 in which the cassette
half-members have an inside wall which describes a circular channel
about the fluid-pumping assembly.
30. A cassette according to claim 27 in which the cassette means
comprises at least one opening therethrough communicating with the
channel, for reception of the fluid-carrying tube, so that it can
enter the channel.
31. A cassette according to claim 27 in which the channel defines a
loop described by the tube in traversing the inside wall of the
cassette.
32. A cassette according to claim 31 in which the channel extends
over an arc within the range from 180.degree. to 360.degree..
33. A cassette for a medical cassette pump having a fluid-pumping
assembly operatively coupled to a drive means for rotation thereby
about a principal axis, said fluid-pumping assembly including at
least two planetary rollers freely rotatably mounted in spaced
relation to said principal axis and to each other, and for
supporting a fluid-carrying tube for the selective engagement of
said tube against at least one of said rollers, comprising a pair
of cassette half-members hingedly joined at one end for relative
pivotal displacement, said cassette half-members being formed so
that when joined together, a central opening is formed therein, at
least a portion of the inner periphery of said central opening
being formed with an axially facing channel for receiving a portion
of said tube for crimping against said rollers each of said
cassette half-members being formed with an opening therethrough
spaced from said hinged connection and providing communication to
said channel for said tube.
Description
Pumps are frequently used for the delivery of fluids to and removal
of fluids from patients where cavities of the body are to be washed
out, such as the stomach, bladder or uterus, or where fluids are to
be pumped from the body. Medical applications in which pumps are
used include infusion, dialysis, hemoperfusion, constant
irrigation, and the suction method of abortion. The fluid being
delivered to or from the patient via the pump should move through a
path in which it does not come into contact with any of the pump
parts, in order to maintain the sterility of the fluid delivered to
the patient, and to avoid contamination of the fluid taken from the
patient. If the pump parts come in contact with the fluid being
processed, it is necessary to clean and sterilize these parts
between uses, which is an expensive and slow procedure.
Peristaltic pumps have been put to medical uses, but they have
required threading of the fluid-carrying tube through intricate
paths in the pump, which has made it difficult to replace the tubes
between uses, and also raise the possibility of contamination of
the tube during the threading operation.
In accordance with the invention, a peristaltic pump is provided in
which a fluid-carrying tube is held against the pumping means by a
readily displaceable cassette, which can be moved between a first
position in which the fluid-carrying tube is held against the pump
means for pumping of fluid through the tube, and a second position
in which the fluid-carrying tube is exposed and can be freed from
such engagement, and removed. Thus, merely by movement of the
cassette between two positions the tube can be inserted, put in a
pumping position for engagement by the pumping means, and replaced
in a simple quick operation, without interference with the sanitary
interior of the tube. No special equipment or tools and removal and
replacement of bolts or screws is required.
The medical cassette pump of the invention comprises, in
combination, a drive means; a fluid-pumping assembly operatively
coupled to the drive means, for rotation thereby about a principal
axis, said fluid pumping assembly including a pumping means
rotatable about the principal axis; cassette means movable between
a first position towards and a second position away from the
pumping means; means defining at least one wall of a channel for
reception of a fluid carrying tube, the wall restraining the tube
from movement away from the pumping means, and retaining the tube
in a path corresponding to the rotational path of the pumping means
in close proximity to the pumping means in a manner such that the
tube is collapsed by the pumping means against the wall; the
cassette means in the first position retaining the fluid-carrying
tube in the channel and in a position to be collapsed by the
pumping means, and in the second position releasing the tube from
such engagement to permit insertion of the tube in the channel or
removal of the tube from the channel, and the pumping means in said
first position of the cassette means being always in engagement
with the tube at some portion of its length, and moving the
collapsed portion along the tube for pumping of fluid through the
tube upon rotation of the drive means.
The cassette means may comprise one or several cassette members
describing segments of the arc of a circle or approximately
circular shape and mounted for relative pivotable movement towards
and away from the pumping means. A pair of cassette half-members
each describing an approximately 180.degree. arc can be pivotably
mounted at one end, in a manner such that when brought together
they extend through an approximately 360.degree. arc about the
fluid drive assembly. They engage the fluid-carrying tube against
an inside wall thereof, which describes a circular channel about
the fluid drive assembly. The cassette means can also be in the
form of a disc, pivotably mounted at one side with the channel
extending about one side of the disc, and enclosing the circular
path followed by the pumping means.
The pumping means is coupled to the drive means for rotation
thereby about its axis, in an arc corresponding to the channel, and
in close proximity thereto, spaced therefrom by a distance equal
only to the diameter of a fluid-carrying tube when collapsed and
therefore closed off by the pumping means against the channel
restraining wall. Thus, where the pumping means engages the tube,
it closes off the tube to fluid flow against the interior wall of
the cassette means, and by its rotation about the principal axis
advances the fluid along the tube in response to the rotation of
the fluid drive assembly.
The medical cassette pump can be formed with a frame and the
cassette means may be releasably mounted on the frame for
simultaneous removal of the cassette and fluid-carrying tube. The
channel can be attached to the frame, or to the cassette means, or
to the pumping means, or any combination of these alternatives.
Thus, the pumping means can comprise grooved rollers or a grooved
cam, with the channel being the groove, and the restraining wall
thereof can be an internal peripheral wall of the cassette
means.
The cassette means can be formed with one or two holes, slots, or
other forms of openings therethrough, in a side thereof, for
reception of the fluid carrying tube, so that it can enter the
channel, each of the openings communicating with the channel.
The cassette means can be pivotably mounted on a shaft upstanding
from the frame, which shaft is adapted to retain the cassette means
secured to the frame. Bias means mounted on the frame can be
provided, for biasing the cassette means into the first position,
holding the fluid-carrying tube in engagement with the pumping
means. The bias means can for instance take the form of a spring,
such as a leaf or coil spring of the compression or tension type,
or a magnet and magnetic member or pair of magnets.
Tab means can be provided, to act with a switch, the tab means
engaging and preventing operation of the switch means operatively
coupled to the drive means, to prevent the operation thereof unless
the tab means is engaged by a tube.
The channel defines the loop described by the tube in traversing
the inside wall of the cassette. This loop may extend over an arc
that is greater or less than 360.degree.. The only requirement is
that a pumping means be continuously in engagement with the loop,
during rotation of the pumping means about the principal axis, to
ensure positive displacement of fluid along the loop.
Thus, if the loop be in excess of 360.degree., one pumping means
will suffice, for advancement of fluid through the tube. If the
loop be less than 360.degree., two pumping means will suffice for
this purpose, but more than two pumping means can be used, such as
three, four or five, or even more, as desired. The spacing of the
several pumping means from each other determines the volume of each
pulse of fluid pumped through the tube, since each pulse is defined
by the distance between adjacent pumping means of the fluid drive
assembly. A large number, three, four or five, of pumping means
give smaller relative pulses, but a more uniform pumped flow, along
the tube.
The pumping means can take any desired form. The design and
configuration of the pumping means in peristaltic pumps are
conventional and form no part of the instant invention. Thus, for
example, the pumping means can take the form of rollers, cams,
fingers or spokes.
Thus, for example, a plurality of planetary rollers rotatably
mounted in spaced relation to the principal axis and to each other
can be used. The planetary rollers can be mounted at one side of a
disc, or on spokes extending from a central hub attached to the
drive shaft. A spoked wheel, the spokes serving as fingers, can be
used, and a cam disc with cam-like protruberances can also be used,
the tips or ends of the cams or fingers engaging and collapsing the
tube in the manner described.
Two or more sets of pumping means can be provided, aligned in two
planes, spaced along the principal axis, each engaging a separate
fluid-carrying tube. The pumping means for each fluid-carrying tube
can be arranged the same or differently, so as to engage and
advance the fluid in each of the fluid-carrying tubes at the same
or different times and in the same or different ways. The pumping
means can be arranged to engage several or all of the tubes
simultaneously, so as to pump fluid through such tubes at the same
rate, although, optionally, not in the same direction, such as for
example, in pumping fluid to and away from the body, to irrigate or
flush a portion of the body.
In one embodiment of the medical cassette pump according to the
invention, planetary rollers are provided composed of a cylindrical
portion and a conical portion extending from one end of the
cylindrical portion, in a manner such that the fluid-carrying tube
rides along the conical portion for positioning and gradual
compression until engagement by the cylindrical portion, at which
point the tube is positioned for pumping operation.
The drawings illustrate preferred embodiments of the invention.
FIG. 1 is a perspective view of one embodiment of medical cassette
pump according to the invention having a pair of cassette members,
and three planetary rollers as the pumping means;
FIG. 2 is a sectional view taken along the line 2--2 of FIG. 1, and
looking in the direction of the arrows;
FIG. 3 is a top plan view of the medical cassette pump of FIG. 1,
showing the cassette half members in the open position;
FIG. 4 is a sectional view taken along the line 4--4 of FIG. 1, and
looking in the direction of the arrows;
FIG. 5 is a sectional view taken along the line 5--5 of FIG. 1, and
looking in the direction of the arrows;
FIG. 6 is a top plan view partially in section of a second
embodiment of medical cassette pump according to the invention;
FIG. 7 is a fragmentary side elevation of the medical cassette pump
of FIG. 6;
FIG. 8 is a sectional view taken along the line 8--8 of FIG. 6;
FIG. 9 is a fragmentary perspective view of a third embodiment of
medical cassette pump according to the invention, having two
planetary rollers as the pumping means;
FIG. 10 is a top plan view of the embodiment of medical cassette
pump of FIG. 9;
FIG. 11 is a sectional view taken along the line 11--11 of FIG.
10;
FIG. 12 is a sectional view taken along the line 12--12 of FIG.
9;
FIG. 13 is a top plan view of a fourth embodiment of medical
cassette pump according to the invention, having three grooved
planetary rollers as part of the channel and the pumping means;
FIG. 14 is a sectional view taken along line 14--14 of FIG. 13;
FIG. 15 is a top plan view of a fifth embodiment of medical
cassette pump according to the invention; and
FIG. 16 is a sectional view taken along the line 16--16 of FIG.
15.
The medical cassette pump indicated generally by 10 shown in FIGS.
1 to 5 is supported on a table 12, which also has a stand 14
mounted thereon. Hanging from the stand 14 is a fluid-dispensing
bottle 16, to which is removably coupled a flexible resilient
fluid-carrying tube 18, for delivery of fluid from the bottle to a
patient by way of a catheter or other delivery device (not shown)
attached to the end 17 of the tube 18. The end 17 of the
fluid-carrying tube 18 can also be connected to a collection
receptacle (not shown) in which case the pump can be arranged to
draw fluid from the patient, and deliver it to the receptacle.
The medical cassette pump 10 includes a housing 22 within which is
mounted an electric drive motor 24, best seen in FIG. 2. An on-off
switch 26 and a reversing switch 28 mounted on the exterior of the
housing 22 are operatively coupled in the electric circuit with the
motor 24, so as to open and close the circuit and thus to turn the
motor on and off, and also to control the direction of rotation
thereof. Rheostat knob 30 mounted on the housing 22 turns a
rheostat (not shown) and thus controls the speed of the drive
motor. These components are conventional, and any design can be
used. Timing and sequence controls permitting the automatic
operation of the pump for predetermined periods, spaced by
predetermined rest intervals, also can be provided. The drive motor
is preferably noiseless and arc-less, so that it can be used in an
oxygen environment.
The drive motor 24 rotates the drive shaft 32, which defines the
principal axis of rotation of a fluid pumping assembly indicated
generally by 34. As best seen in FIG. 2, the fluid-pumping assembly
34 is composed of a central hub 36, secured to drive shaft 32 by a
set screw 38, and rotating therewith. A pair of spaced circular
discs or plates 40 are mounted on each end of hub 36 by screws 42,
for the rotation of the plates with the hub and drive shaft. Three
spaced planetary rollers 44 are freely rotatably mounted between
plates 40 upon roller shafts 46.
As best seen in FIG. 3, the three rollers 44 are circumferentially
placed about the outer periphery of the plates 40, and are equally
spaced from each other and the drive shaft 32. The three rollers 44
are carried in a circular path about the principal axis of rotation
by the drive shaft 32.
A cassette 48 is provided, comprising a pair of cassette
half-members 50, 50', joined at one end by a common hinge 52, best
seen in FIG. 5. The hinge 52 is provided with an axial aperture 54
therethrough, engaging a post 56 projecting upwardly from the
housing 22. The post 56 serves as a pivot pin for the pivotal
movement of the two cassette half-members 50, 50' with respect to
each other and the drive assembly, as well as positioning the
cassette on the housing.
If the motor 24 is to be of the unidirectional type, the aperture
54 could be closed at one end by a wall, to prevent accidental
reversal of the direction of fluid flow.
As shown in FIG. 3, the two cassette half members are swung apart
to open the cassette, and together to close the cassette. They also
may be lifted off the post 56, for removal from the housing. The
other end 57, 57' of each cassette half member 50, 50' is provided
with a notch 58, 58', which cooperates with a spring finger 60, 60'
as best seen in FIG. 4. Each of the spring fingers 60, 60' is
mounted at one end to the housing 22 by a screw 62, 62', and each
extends through an aperture 64, 64' in the housing. The aperture
permits the movement of the spring finger to the position shown in
phantom lines in FIG. 4, to permit the pivoting of the associated
cassette halfmember 50. A pad 66 at the end of each spring finger
60 engages the top surface of each cassette half-member 50, 50' to
prevent the upward displacement of the cassette half-members.
Each cassette half-member is formed with a substantially
semi-circular inner peripheral wall 68, 68', dimensioned to extend
about and receive plates 40, and serving as a retaining wall for
the tube 18. In this embodiment, the portion of the inner
peripheral wall 68, 68' of each of the cassette half-members
retaining the tube is formed as the base, 72, 72' of a U-channel
70, 70', and is integral with the cassette half-member. The channel
70 can also be a separate component, pivotably mounted to the post
56 or frame 22, and movable with the cassette half-member.
The two cassette half-members together describe an arc of
360.degree. about the fluid-pumping assembly, each extending over
about 180.degree.. The channels, 70, 70' extend over the same
arc.
As best seen in FIG. 2, the rollers 44 are dimensioned to extend
into the channels 70, to engage fluid-carrying tube 18 and thrust
it in a flattened condition against the base wall 72, 72', of the
channels 70, 70', as shown in the left portion of FIG. 2. Channel
70 is dimensioned to loosely receive the fluid-carrying tube 18,
when the tube 18 is not in engagement by the rollers 44, and to
permit the flattening of the tube 18 against the inner wall 72 by
the rollers 44, closing off the tube at that point, and defining a
pulse of fluid within the tube that is advanced along the tube by
the rollers as they are rotated by the shaft 32 about their
circular path.
Each of the cassette half-members is also provided with a curved
bore 74, 74' communicating with channels 70, 70', as best seen in
FIG. 3. The bores are spaced approximately 120.degree. apart, so
that the channels 70, 70' extend over an uninterrupted arc of
240.degree. and 120.degree..
In operation, the fluid-carrying tube 18 is threaded through the
bores 74, 74', and received within the channels 70, 70', over the
longer arc of approximately 240.degree.. The cassette half-members
50, 50' are then mounted on the post 56, while in the open position
as shown in FIG. 3. Then, the two cassette half-members 50, 50' are
brought together into the position in phantom lines in FIG. 3. When
so positioned, at least two of the three rollers 44 at any given
interval thrusts a portion of the fluid-carrying tube 18 against
the inner wall 72, 72' of the channels 70, 70', to effectively
close the tube at that point. A pulse of fluid is defined between
such two rollers, which pulse is advanced along the tube as the
fluid-pumping assembly 34 is rotated. Before any roller 44 leaves
contact with the tube at one end of the arc, the next-preceding
roller 44 has engaged the tube at the other end of the arc, so that
a pulse of fluid is always being advanced along the tube.
Each pulse of fluid is sequentially delivered to the outlet portion
of the fluid-carrying tube located in the bore 74', while a new
pulse of fluid at the inlet portion 74 is formed by the next
roller, in sequence, and advanced along the section of the
fluid-carrying tube and delivered to the outlet portion. In this
manner a smooth and continuous flow of fluid is produced, in either
desired direction of flow, without any of the moving parts of the
pump being in contact with the fluid being transmitted.
If desired, cassette 48 may be assembled with the tube, and
furnished as a unit, each such unit constituting a complete
disposable cassette. This system can be sterilized as a unit,
utilized as a unit, utilized as a unit, and disposed of as a unit.
Whether or not the cassettes are disposable, a plurality of
cassettes 48 may be provided, each of the cassettes engaging a
separate tube, so upon completion of one operation, a pump may be
immediately utilized for another operation by merely substituting a
new cassette for the old one, including a fluid-carrying tube
already threaded thereon. This substitution is readily and quickly
made.
The pump is provided with a pair of handles 76, 78, which permit
the carrying of the pump, its mounting on a stand, or the
selfsupport thereof.
The embodiment of medical cassette pump of FIGS. 6 to 8, generally
designated 80 in these Figures, comprises a drive shaft 32', with a
hub 36' mounted and held thereon by set screw 38'. A pair of
circular plates 40' are secured to the hub by screws 42'. In this
embodiment, the planetary rollers 82, which are freely rotatably
mounted in circumferentially spaced relation on shaft 46', are
formed with a cylindrical surface portion 84 and a conical surface
portion 86. The cassette 88 comprises a unitary cassette member 90
and a handle member 92. The cassette member 90 is formed with an
inner central opening 94, the inner periphery of which defines a
relatively shallow channel 96 (See FIG. 8), the base wall 100 of
which serves as a retaining wall for a tube 18. The central opening
94 in the cassette member 90 is dimensioned to receive the
cylindrical portion 84 of rollers 82, with a close clearance
between portion 84 and base wall 100, so that a tube 18 in the
channel is collapsed by the roller 82 against the wall 100 and
closed off at that point.
The cassette member 90 is formed with a pair of curved bores 98,
98' spaced approximately 120.degree. apart and communicating with
the channel 96. The channel thus defines a 360.degree. arc, with
120.degree. and 240.degree. portions between the bores 98, 98'. The
fluid-carrying tube 18 is threaded through the bores, around the
240.degree. arc of the channel 96. Since the channel is relatively
shallow, portions of the fluid-carrying tube 18 project laterally
out of the channel, but where in engagement with the cylindrical
portion 84 of the rollers 82, the tube 18 is compressed and
flattened between the rollers and the wall 100 of the channel
96.
The cassette 88 is mounted on housing 22' by four upstanding posts
102, which project from the top of the housing. Each of the posts
is provided with a spring-loaded detent 104, which engages a
corresponding recess in the cassette member 90, to releasably
retain the cassette member 88 in position. The cassette is mounted
and removed by grasping the handle 92, and moving the cassette
along the principal axis defined by the drive shaft 32' towards or
away from housing 22'.
The conical surfaces 86 of the rollers 82 permit the fluidcarrying
tube 18 to ride therealong, and to be gradually compressed and
released, and also serve as a centering device for the positioning
of the cassette.
Alternatively, rollers 82 may be substantially cylindrical, but
mounted for radial displacement relative to the principal axis of
the drive shaft 32'. In this embodiment, the pancake-shaped
cassette member 90 would be positioned about the fluid-pumping
assembly, and the rollers would be displaced outwardly into the
channel 96, to engage the fluid-carrying tube against the inner
wall 100, and locked in this position.
In another alternative embodiment, the fluid-pumping assembly can
be formed integrally with the pancake-shaped cassette member 90,
the combination being keyed to and removably mounted on the drive
shaft 32'.
The cassette 88 may be disposable, and a plurality of such
cassettes may be utilized, to permit the quick substitution of one
cassette for another, as in the case of the embodiment of FIGS. 1
to 5.
It will be apparent that the operation of this embodiment is the
same as FIGS. 1 to 5, and consequently, the operation will not be
described.
The embodiment of medical cassette pump shown generally as 110 in
FIGS. 9 to 12 is adapted for the simultaneous pumping of fluid in
the same direction (but in fact in opposite directions in the fluid
system) through two separate fluid-carrying tubes 112, 114. As best
seen in FIG. 11, the fluid-pumping assembly shown generally as 116
is provided with two roller sets, each composed of three rollers,
118, 120, one roller of each set being mounted on a common shaft
122 for free rotation thereabout. Each of the common roller shafts
122 are secured to a hub member 124, which in turn is fixedly
mounted on the drive shaft 125, for rotation thereby. The hinged
cassette 126 is provided with a pair of cassette half-members 128,
128', and extending along the portion of the inner peripheral walls
thereof are channels 130, 130', 132, 132' dimensioned to receive
the corresponding pairs of rollers 118, 120, and the fluid-carrying
tubes 112, 114. The cassette 126 is mounted on the housing 134 by
the post 136, extending through the hinge 138 joining the two
cassette half-portions, and by the spring fingers 140.
The cassette has four open slots 142, which communicate with the
channels 130, 130', 132, 132', and permit the insertion of the
fluid-carrying tubes therein without threading the tubes through
bores of the cassette. This permits permanent mounting of the
cassette on the housing by means of the pin 136.
In order to position and retain the fluid-carrying tubes, and to
permit their easy insertion in and removal from the pump 110, a tab
member 144 (see FIG. 9) is provided having four apertures 146,
positioned in two aligned spaced pairs opposite the slots 142. Each
of the fluid-carrying tubes 112, 114 is threaded through the two
apertures, 146 of each pair, and about the channels 130, 130', 132,
132' to define a 240.degree. loop in each of the tubes in which at
least two of the rollers 118, 120 engage the tubes 118, 120 at any
given moment. Pivoting the cassette half-members 128, 128' to the
closed position shown in FIG. 10 brings the rollers 118, 120 into
engagement with the tubes 118, 120 over this 240.degree. loop. They
are released for removal from the channels 130, 130', 132, 132' by
pivoting the half-members 128, 128' away from this position.
Tab 144 is provided with a handle 148, and is also adapted to serve
a further safety switching function. For this purpose, tab 144 is
provided with a projecting finger 150, as best seen in FIGS. 9 and
12. The finger projects through an aperture 152 in housing 134 into
a switch block 154. As shown in FIG. 12, the finger 150 engages a
displaceable switch member 156 against a switch member 158, to
close an enabling circuit, which when open will not permit the
motor to operate. The circuit is connected by the leads 160, 162 to
the drive motor of the pump. The displaceable contact 156 is in the
form of a leaf spring, which will move to the open position when
finger 150 of tab 144 is withdrawn. This ensures that the pump will
only operate when the fluid-carrying tubes are properly positioned.
A tab arrangement such as tab 144 can also be incorporated in pumps
using only a single fluid-carrying tube.
The two-tube embodiment of FIGS. 9 to 12 permits the coordinated
withdrawal and delivery of fluids from the body, and is
particularly useful in flushing out cavities such as the stomach,
intestine, and the like, and in particular in drug or poison cases,
where the stomach must be washed out rapidly. The two sets of
planetary rollers can also be mounted on separate hubs joined by a
clutch mechanism, so that the two sets can be selectively
operatively coupled to the drive shaft. This arrangement permits
intermediate fluid delivery or withdrawal while maintaining
continuous withdrawal or delivery, respectively.
The fluid-carrying tubes can also include concentric tubes, one
within the other, for simultaneous delivery of two fluids at the
same time. Two, three or more fluid-carrying tubes can be driven,
if desired, simply by providing an adequate supply of pumping
means. Closed disposable delivery and collection systems can be
arranged for, with the fluid receptacle, fluid-carrying tube, and
fluid passage means (such as a catheter) all formed as a unit. The
medical cassette pump according to the invention provides a
flexible efficient and sanitary pumping system, which can be
utilized for a wide range of medical and other functions.
The medical cassette pump shown generally as 1 in FIGS. 13 and 14
includes a mounting plate 2 on which is mounted a drive motor 3,
best seen in FIG. 14. The plate can mount the pump on a cabinet or
table, the pump mechanism fitting within the cut-out portion. As
on-off switch and a reversing switch (not shown) are operatively
coupled to drive the motor 3 so as to turn the motor on and off and
control the direction of rotation thereof. Means also can be
provided to control the speed of the drive motor. Timing and
sequence controls permitting the automatic operation of the pump
for predetermined periods spaced by predetermined rest intervals
also can be provided. The drive motor is preferably noiseless and
arcless, so that it can be used in an oxygen environment.
The drive motor 3 rotates the drive shaft 4 which defines the
principal axis of a fluid-pumping assembly 5. The fluid-pumping
assembly is composed of a central hub 6 secured to drive shaft 4,
and a pair of spaced wings 7 extend from hub 6 and are integral
therewith for rotation of the wings with the drive shaft. Two
planetary rollers 8 are freely rotatably mounted on wings 7 by
roller shafts 9, cradled by arms 11.
As best seen in FIG. 13, the two rollers are circumferentially
spaced 180.degree. apart about the wings 7, and are equally spaced
from the drive shaft 4. The two rollers are carried about the
principal axis by rotation of the drive shaft 4.
A cassette 15 is provided comprising a pair of cassette
half-members 19, 19' joined at one end by a pivot post 21 mounted
on plate 2. The post 21 is provided with a cap 23 and a washer 25
on each side of the members 19, 19'. The post 21 serves as an axis
for the relative pivotal movement of the two cassette half-members
19, 19', as well as serving to retain the cassette 15 in position
on the housing 2.
The two cassette half-members are pivoted away from each other to
open the cassette. The other end of each cassette half-member 19,
19' is provided with a notch 27, 27' which cooperates with a spring
finger 29, 29', as best seen in FIG. 14. Each of the spring fingers
is mounted at one end to the plate 2 by a screw 31, and extends
through an aperture 33 in the plate. The aperture permits the
displacement of the spring finger to the position shown in phantom
lines in FIG. 14, to permit the pivoting of the associated cassette
half-member 19, 19'.
Each cassette half-member is formed with a substantially
semi-circular inner peripheral wall 35 dimensioned to extend about
and receive wings 7. In this embodiment at least a portion of the
inner peripheral wall 35 of each of the cassette half members is
formed with a channel 37, 37' having a base wall 39, 39' serving as
a retaining wall for a fluid-carrying tube 18.
As best seen in FIG. 13 the rollers 8 are dimensioned to extend
into the channels 37, 37' to engage fluid carrying tube 18 against
the base walls 39, 39' of the channels, as shown in the left
portion of FIG. 14. The channels 37, 37' are dimensioned to loosely
receive the fluid-carrying tube 18 when not in engagement by the
rollers, and to permit the flattening thereof against the inner
walls 39, 39' by the rollers 8, thus defining a pulse of fluid
within the tube, that is advanced along the tube by the rollers 8
as they rotate about the drive shaft 4. Each channel 37, 37' of the
cassette half members terminates in a curved slot 41, 41', as best
seen in FIG. 13.
In operation, with the cassette half-members 19, 19' in the open
position shown in phantom lines in FIG. 13, fluid-carrying tube 18
is placed in the channels 37, 37', extending through the curved
slots 41, 41', and looping in an arc of approximately 320.degree.
about the drive assembly 5. Then, the two cassette half-members 19,
19' are brought together into the closed position shown in FIG. 13.
When so positioned at least one and sometimes both of the two
rollers 8 engage a portion of the fluid-carrying tube 18 against
the inner wall 39, 39' of the channels 37, 37' to effectively close
the tube. A pulse of fluid is defined before each roller engaging
the tube, which pulse is advanced along the tube as the roller
travels its circular path about the channels 37, 37' when the fluid
drive assembly 5 is rotated.
Each pulse of fluid is sequentially delivered to the outlet portion
41' of the channel 37', while a new pulse of fluid is formed by the
next roller 8, as it contacts the tube at inlet portion 41, of
channel 37, and advanced in sequence along the fluid-carrying tube
by the roller, and delivered to the outlet portion 41'. In this
manner, a smooth and continuous flow of fluid in either direction
is produced, without any of the moving parts of the pump being in
contact with the fluid being transmitted.
The medical cassette pump shown in FIGS. 15 and 16 includes a
housing 51 within which is mounted a drive motor 53. An on-off
switch and a reversing switch are operatively coupled to drive the
motor 53, so as to turn the motor on and off, and control the
direction of rotation thereof. Means can be provided to control the
speed of the drive motor. Timing and sequence controls permitting
the automatic operation of the pump for predetermined periods
spaced by predetermined rest intervals also can be provided. The
drive motor is preferably noiseless and arcless, so that it can be
used in an oxygen environment.
The drive motor 53 rotates the drive shaft 55 which defines the
principal axis of a fluid-pumping assembly 57. The fluid-pumping
assembly is composed of a central hub secured to drive shaft 55 by
a set screw 61. A pair of wings 63 extend from and are integral
with hub 59 for rotation of the plates with the drive shaft. Two
planetary rollers 67 are freely rotatably mounted on roller shafts
69, which are cradled on arms 71. The arms 71 are pivotably mounted
to the wings 63 by pins 73, and spring-biased outwardly relative to
the drive shaft 55 by compression springs 75 attached to hub
59.
As best seen in FIG. 15, the two rollers 67 are circumferentially
spaced 180.degree. apart about the wings 63 and are equally spaced
from the drive shaft 55. The two rollers are carried in a circular
path about the principal axis of rotation by the drive shaft 55.
Each roller has a central groove 77 which accommodates the
fluid-carrying tube 18.
A cassette 81 is provided, comprising a pair of cassette
half-members 83, 83' joined at one end by a pivot pin 85, best seen
in FIG. 16. The pin projects upwardly from the housing 51. The pin
serves as an axis for the relative pivotal movement of the two
cassette half-members 83, 83', as well as serving to retain the
cassette in position on the housing 51.
As shown in FIG. 15, the two cassette half-members 83, 83' are
pivoted away from each other to open the cassette. The other end of
each cassette half-member is provided with a notch 87, 87' which
cooperates with a spring finger 89, 89' as best seen in FIG. 16.
Each of the spring fingers is mounted at one end to the housing 51
by a screw 91, and extends through an aperture 93 in the housing.
The aperture permits the displacement of the spring finger to the
position shown in phantom lines in FIG. 16, to permit the pivoting
of the associated cassette half-member 83, 83'.
Each cassette half-member is formed with a flat substantially
semi-circular inner peripheral wall 95, 95' dimensioned to extend
about and receive wings 63. In this embodiment, the groove 77 of
each roller 67 serves as the channel for the fluid-carrying tube
18.
As best seen in FIG. 15, the grooves 77 are dimensioned to compress
and flatten the fluid-carrying tube 18 against the inner walls 95,
95' of the cassette half-members 83, 83', as shown in the left
portion of FIG. 15. The fluid-carrying tube 18 lies free and
expanded when not in engagement by the rollers 67. Thus, the
rollers 67 define a pulse of fluid within the tube before them,
that is advanced along the tube by the rollers as they rotate along
their circular path about the principal axis of the drive shaft 55.
Each of the cassette half-members 83, 83' is provided with a curved
end 97, defining an opening 99 therebetween, as best seen in FIG.
15. The members describe an arc of approximately 320.degree.
between the two sides of opening 99.
In operation, with the cassette half-members in the open position
shown in phantom lines in FIG. 15, fluid-carrying tube 18 is placed
in a loop of approximately 320.degree. over the rollers 67. Then
the two cassette half-members 83, 83' are brought together into the
closed position in FIG. 15. When so positioned, the ends of the
tube 18 both pass through opening 99, and at least one and
sometimes two of the two rollers 67 engages a portion of the
fluid-carrying tube against the inner walls 95, 95' of the members
83, 83', flattening it so as to effectively close the tube there.
One of the rollers 67 is always flattening the fluid-carrying tube
against the wall at any given interval, and a pulse of fluid is
defined ahead of such roller, which pulse is advanced along the
tube by that roller as the fluid-pumping assembly 57 is
rotated.
Each pulse of fluid is sequentially delivered to the outlet portion
of the fluid-carrying tube located at opening 99, while a new pulse
of fluid is formed by the next roller, in sequence, and advanced
along the section of the fluid-carrying tube by the roller as it
moves about its circular path, and delivered to the outlet portion.
In this manner, a smooth and continuous flow of fluid in either
direction is produced, without any of the moving parts of the pump
being in contact with the fluid being transmitted.
* * * * *