United_ States Patent
`Dodge et al.
`
`[19]
`
`_
`
`5,017,192
`[11] Patent Number:
`[45] Date of Patent: May 21, 1991
`
`[54] FREE FLOW PREVENTION SYSTEM FOR
`INFUSION PUMP
`
`................. 417/360
`4,313,190 4/1939 Pelmulder et al.
`OTHER PUBLICATIONS
`
`[751
`
`1"Ve'“°r5= 1-4"? H- D053“? 5“;““’°'d C- 5*°"°v
`b°th °f St’ Paul’ Mm‘
`[73] Assignee; Minnesota Mining and
`Mfm“f“°t“"i“3 C°“‘P‘mYv -St- Paul»
`Mm“
`[21] APPL Non 424,385
`
`-
`
`[22] Filed:
`
`Oct. 20, 1989
`
`Int. CL5 ............................................... A61M 5/00
`[51]
`[52] U.S. Cl. ....................................... .. 604/250; 251/7
`[53] Field of Search ................. 604/250, 246, 245, 34;
`251/4} 137/637
`’
`
`[56]
`
`References Cited
`U S PATENT DOCUMENTS
`'
`'
`
`. 137/315
`gsclle -
`'
`4
`9 “‘°‘'_ -------------------------------
`_
`-
`3’216’418 11/ 1965 S°‘.Sl°w'°z ‘
`3,316,935
`5/1967 Kaiser et al. ........................ 137/595
`
`.
`
`3M Flyer “AVIZOOA Infusion Pump: The Advanced
`Technology Volumetric Infusion Pump” IMED Cor-
`poration Brochure Gemini TM Administration Sets.
`Primary Examt'ner—Stephen C. Pellegrino
`Assistant Examiner—Ralph A. Lelois
`Attorney, Agent, or Firm—5Gary L. Griswold; Walter N.
`Kim; Stephen W. Bauer
`
`[571
`
`ABSTRACI‘
`
`A free flow prevention system for preventing free flow
`°f fluid “"°“5h. ‘V .‘“‘’i“3 “he” ‘h°.‘“‘’i“g ‘5 d.“°°“'
`nected from aninfiision pump_. A flexible clamp is pro-
`vided having a pair of clamping arms, which define a
`variable width slot for receiving the IV tubing. The IV
`tubing may be moved along the slot between a first
`position wherein the width of the slot is sufficient to
`permit the clamp to be positioned longitudinally along
`the IV tubing, and a second position wherein the width
`of the slot is normally less than the width of the slot at
`.
`.
`.
`.
`.
`the first position. The clamping arms are resiliently
`.
`1
`.
`.
`h
`.
`h V
`.
`.
`blmd ‘° 3 ° 0?“? P°5‘*‘°“ W _eFe“‘
`t 9 I
`iubmg 15
`Squeezed Wher}1n its Second P0SIt10I1t_0_e10Sethe1umen
`to prevent fluid flow. A clamp—receiving passageway
`‘and clamp-opening wedge are provided on the infusion
`pump. The clamp-opening wedge is movable relative to
`a clamp received in the passageway to an operating
`position, wherein the wedge moves the arms of the
`flexible clamp against their bias to an open position
`wherein the lumen of the IV tubing is allowed to open
`to permit fluid flow during operation of the pump.
`
`'
`
`36 Claims, 3 Drawing Sheets
`
`..... 251/5
`. 137/595
`417/47s
`137/436
`_
`
`.
`
`..
`.-
`
`9/1973 Baxter .......... ... ...
`3,759,483
`4,230,151 10/,19so Jonsson ..................
`4,236,880 12/1980 Archibald ..............
`4,251,333 4/1931
`4,277,226
`7/1981
`4.322.201
`3/1982
`4v434»953
`3/1934
`41460358
`7/1984
`4’519’-792
`5/1985
`fi’§§;’fi5l3
`5/1986
`4'536’691
`4,620,564 ll/1986
`4,689,043
`8/1987
`
`'
`'
`
`‘
`
`'
`
`lIr—-'1I
`
`--
`
`ACTA EX. 1018-001
`
`ACTA Ex. 1018-001
`
`

`
`U.S. Patent
`
`L May 21,1991
`
`Sheet" 1 .113
`
`5,017,192
`
`ACTA Ex. 1018-002
`
`

`
`U.S. Patent
`
`May 21,1991
`
`1'
`
`‘Elm’ ""
`!iI{l'l_T1'_I"iflH
`
`y
`
`%
`
`
`
`ACTA Ex. 1018-003
`
`

`
`U.S. Pafent
`
`I
`
`May 21, 1991 A
`
`Sheet 3 of 3
`
`, 5,017,192
`
`ACTA Ex. 1018-004
`
`

`
`1
`
`FREE FLOW PREVENTION SYSTEM FOR
`INFUSION PUMP
`
`5,017,192
`
`BEST AVAILABLE COPY
`
`The invention relates generally to infusion pumps and
`_ IV tubing sets for the controlled delivery of fluids to a
`’ patient, and more particularlyto a free flow prevention
`system for preventing free flow of fluid through the IV
`tubing when the tubing is disconnected from the infu-
`sion pump.
`BACKGROUND OF THE INVENTION
`
`Infusion pumps are typically used to regulate the
`delivery of fluids, which may include .potentially haz-
`ardous drugs, to a patient with a high degree of accu-
`racy. Ordinarily, a roller clamp is moved to a closed
`position to stop flow through IV tubing before the
`tubing is removed from an infusion pump in order to
`prevent a situation that is sometimes referred to as “free
`flow” or “fluid runaway”, that is, where thefluid is free
`to flow rapidly through the IV tubing without regula-
`tion by the infusion pump. Such roller clamps are effec-
`tive in preventing free flow only when they are manu-
`ally moved to their closed positions, and free flow or
`fluid runaway may occurif the roller clamp is left in its .
`open ‘position. As a result, an automatic free flow pre-
`vention system is now desired wherein fluid runaway is
`prevented regardless of whether the pump operator
`remembers to close a roller or slide clamp.
`One approach is described in co-assigned U.S. Pat._
`No. 4,585,441 wherein an interlock is provided to pre-
`vent removal of the IV set unless fluid flow through the
`tubing is stopped. The pump operator must manually
`close a clamp to stop fluid flow through the tubing
`before the infusion pump will permit removal of the IV
`set.
`
`Another approach is to provide a permanent clamp
`on the infusion pump itself from which the IV set must
`be manually disconnected during removal of the IV set
`from the infusion pump. That approach reduces the risk
`of fluid runaway because the permanent clamp reduces
`the possibility of thoughtless removal of the IV set from
`the infusion pump. The act of disconnecting the IV set
`from the permanent clamp tends to remind the operator
`of the need to close the roller or slide clamp on the IV
`set; however, it does not eliminate the risk that the
`operator will remove the IV set without closing a
`clamp.
`A
`Other approaches include employing slide clamps to
`prevent or reduce the risk of removing the IV set with-
`out closing a clamp. U.S. Pat. Nos. 4,586,691; 4,689,043
`and 4,818,190 describe employing slide clamps to pre-
`vent fluid runaway during removal of IV sets from
`infusion pumps.
`'
`SUMMARY OF THE INVENTION
`
`The invention provides a free flow prevention system
`adapted for preventing free flow of fluid through IV
`tubing when the tubing is disconnected. from. am infusion
`pumpt The system is desigpd to be easy; than use, and to 60
`automatically close the IV tubing to fluid flow when
`the tubing is disconnected from the infusion pump.
`Generally, the free flow prevention system comprises
`IV tubing having a lumen through which fluid may be
`pumped for administration to a patient, and a flexible
`clamp associated with the IV tubing. A pumping assem-
`bly is provided that includes pumping means for pump-
`ing fluid through the IV tubing, and releasable holding
`
`65
`
`2
`means for holding the IV tubing during operation of the
`pumping assembly.
`The flexible clamp has a pair of clamping arms defm-
`ing a variable width slot along which the IV tubing may
`be moved between a first position wherein the width of
`the slot is sufficient to permit the clamp to be positioned
`longitudinally along the IV tubing, and a second posi-
`tion wherein the width of the slot is normally‘ less than
`the width of the slot at the first position. The clamping
`arms are resiliently biased to a closed position wherein
`the IV tubing is squeezed when in its second position to
`close the lumen to prevent fluid flow, and are movable
`against the bias. to an open position wherein the lumen
`of the IV tubing is allowed to open so that flow through
`the lumen is permitted.
`' Clamp-receiving means are provided on the pumping
`assembly for releasably receiving the flexible clamp,
`and releasable clamp-opening means are provided for
`separating the clamping arms of the flexible clamp and
`moving the arms from their closed position to the open
`position before operation of the pumping assembly. The
`clamp-receiving means and clamp-opening means are
`mounted on the pumping assembly for movement of the
`clamp-opening means relative to the flexible clamp
`received in the clamp-receiving means between an un-
`loading position and an operating position. In the un-
`loading position,
`the clamp-opening means does not
`hold the arms of the flexible clamp in their open posi-
`tion.
`In the operating position,
`the clamp-opening
`means moves the arms of the flexible clamp to their
`open position and holds the arms in the open position.
`Other features will be in part apparent and in part
`pointed out hereinafter.
`BRIEF DESCRIPTION OF THE DRAWING
`
`The invention will be further described with refer-
`ence to the drawing wherein corresponding reference
`characters indicate corresponding parts throughout the
`several views of the drawing, and wherein:
`FIG. 1 is a perspective view of an infusion pump
`incorporating the free flow prevention system of the
`invention;
`’
`FIG. 2 is a cross-sectional view substantially along
`line 2-2 of FIG. 1, showing a flexible clamp of the free
`flow prevention system in its closed position;
`FIG. 3 is a cross-sectional view similar to FIG. 2,
`showing the flexible clamp in its open position;
`FIG. 4 is an enlarged bottom plan view of the flexible
`clamp of FIGS. 2 and 3;
`FIG. 5 is a bottom plan view similar to FIG. 4, illus-
`trating another embodiment of the flexible clamp; and
`FIG. 6 is a cross-sectional view similar to FIGS. 2
`
`and 3 showing a second embodiment of a clamp-receiv-
`ing mechanism of the invention.
`
`DETAILED ‘DESCRIPTION
`The infusion pump designated in its entirety by the
`reference numeral 10 in FIG. I may be of the general
`type described in U.S. Pat. Nos. 4,236,880; 4,277,226
`and 4,322,201 (incorporated herein by reference). Such
`infusion pumps are designed for use with IV tubing 12
`that includes a pumping cassette having flexible walls
`defining fluid pumping chambers which may be com-
`pressed to regulate fluid flow through the IV tubing 12.
`Infusion pumps of this type are being sold by AVI, Inc.,
`a" subsidiary of Minnesota Mining and Manufacturing
`Company of St. Paul, Minn., under the various trade
`designations of the “AVI 200” and “AVI 400” model
`
`ACTA EX. 1018-005
`
`ACTA Ex. 1018-005
`
`

`
`5,017,192
`
`55
`
`3
`series infusion pumps. The infusion pump 10 may alter-
`natively be of the type commonly referred _to as a “lin-
`ear peristaltic pump”, that is, pumps that selectively
`squeeze straight portions of the IV tubing to regulate or
`pump fluid through the IV tubing. In any "event, the
`infusion ‘pump 10 regulates fluid flow through the
`lumen of IV tubing 12 for administration to a patient.
`The infusion pump 10 includes a pumping assembly
`shown generally at 14 employing conventional pump- .
`hing means for pumping fluid through the IV tubing 12,
`and a releasable holding means or assembly 16 for hold-
`ing the IV tubing 12 during operation of the pumping
`assembly 14. Clamp-receiving means, such as the walls
`forming an elongate passageway 18 having an open end
`19, are provided on the releasable holding means 16 of
`the pumping assembly 14 for releasably receiving a
`flexible clamp 20 associated with the IV tubing 12. And
`releasable clamp-opening means 22 are provided for
`separating the clamping arms 24 of the flexible clamp 20
`and moving the arms 24 from their closed position
`(FIG. 2) to the open position (FIG. 3) before operation
`of the pumping assembly 14 so that fluid can ‘flow
`through the IV tubing 12.
`The clamp-receiving means 18 and clamp-opening
`means 22 are mounted on the infusion pump 10 for
`movement of the clamp-opening means 22 relative to a
`flexible clamp 20 received in the clamp-receiving means
`18 between an unloading position (FIG. 2) and an oper~ .
`ating position (FIG. 3). In the unloading position (FIG.
`2),‘the clamp—opening means 22 does not hold the arms
`24 of the flexible clamp 20 in their open position so that
`flow through the lumen of the IV tubing 12 is prevented
`before unloading the IV tubing set from the infusion
`pump 10. When the clamp-receiving means 18 and
`clamp-opening means 22 are moved from the unloading
`position to the operating position (FIG. 3), the clamp-
`opening means 22 moves the arms 24 of the flexible
`clamp 20 to their open position and holds the arms 24 in
`the open position.
`The flexible clamp 20 (FIG. 4) includes at least a pair
`of the clamping arms 24, which define a variable width
`slot 26. The IV tubing 12 may be_moved along the slot
`26 between a first position 28 (FIG. 4) wherein the
`width of the slot 26 is sufficient to permit the clamp 20
`to be positioned longitudinally along the IV tubing 12,
`and a second position 30 wherein the width of the slot
`26 is normally less than the width of the slot 26 at the
`first position. The clamping arms 24 are resiliently bi-
`ased to _a closed position (FIGS. 2 and 4) wherein the IV‘
`tubing 12 is squeezed when in its secondzposition 30
`(FIG. 2) to close the lumen to prevent fluid flow. The
`clamping arms 24 are movable against the bias to an
`open position (FIG. 3) wherein the lumen of the IV
`tubing 12 is allowed to open so that flow through the
`lumen is permitted.
`As shown in FIGS. 2 and 3, the releasable holding
`means 16 is preferably in the form of a door assembly 16
`including an IV pumping cassette-receiving block 32 of
`the type described in co-assigned U.S. Pat. No.
`4,236,880, and a door 34 pivotably inountesii on the 60
`cassette-receiving block 32 by a hinge. As described in
`the co-assigned U.S. patent, the door assembly 16 may
`be manually: moved between a loading and unloading
`position (FIG. 2) and an operating position.(FIG. 3) by
`turning a knob 36 extending laterally outwardly from a
`side of the infusion pump 10. In the loading and unload-
`ing position (FIG. 2), the door assembly 16 is spaced
`from the main body 38 of the infusion pump 10 a dis-
`
`4
`tance D-1 sufficient to permit the door 34 to be pivoted
`outwardly for loading and unloading the pumping cas-
`sette of the IV tubing 12. When the door assembly 16 is
`moved to the operating position (FIG. 3), _the door
`assembly 16 is moved toward the main body 38 of the
`infusion pump 10 to bring the pumping cassette into
`position for proper operation of the pistons of the
`pumping means.
`The clamp-opening means 22 preferably includes a
`wedge 22 mounted on the main body 38 of the pumping
`- assembly 14, and the clamp-receiving passageway 18 is
`preferably formed in the cassette-receiving block 32 of
`the door assembly 16. For example, a guide block 37
`i may be provided on the cassette-receiving block 32 to
`15
`form the passageway 18. When the door assembly 16 is
`in its loading and unloading position (FIG. 2), the IV
`tubing 12 may be loaded into or unloaded from the
`pumping assembly 14, and the wedge 22 and flexible
`clamp 20 are in their unloading position after the clamp
`20 is fully inserted in the clamp-receiving passageway
`18. And when the door assembly 16 is moved to the
`operating position (FIG. 3), the flexible clamp 20 is
`carried along in the clamp-receiving passageway 18
`toward the wedge 22 to the operating position, with at
`least a portion the wedge 22 positioned between the
`clamping arms of the flexible clamp to move the clamp-
`ing arms 24 to their open position.
`A projecting portion or pin 35 preferably extends
`downwardly from the bottom edge 39 of the door 34.
`The pin 35 is adapted for releasably retaining the flexi-
`ble clamp 20 in the elongate passageway 18 after the
`clamp 20 is manually inserted in the passageway 18 and
`the door 34 is closed against
`the cassette-receiving
`block 32. It will be observed that the pin 35 does not
`prevent removal of the clamp 20 when the door 34 is
`open. The pin 35 engages a ledge 40 extending laterally
`outwardly from the inner end of one of the clamping
`arms 24 to hold the clamp 20 against longitudinal move-
`ment (downwardly in FIGS. 2 and 3) when the wedge
`22 separates the clamping arms 24 of the clamp 20.
`The flexible clamp 20 preferably comprises a body
`formed of thermoplastic or synthetic resin material, and
`a resilient spring member 42 biasing the clamping arms
`24 to their closed position (FIG. 2). The body of the
`flexible clamp 20 includes a hinged bridging portion 44
`defining an inner end of the slot 26, and the clamping
`arms 24. The clamping arms 24 of the clamp 20 extend
`outwardly (upwardly in FIG. 4) from the bridging por-
`tion 44, and terminate in free ends 46 that define the
`outer end of the slot 26. The free ends 46 of the clamp-
`ing arms 24 are tapered inwardly toward the slot 26 and
`bridging portion 42 to guide the wedge 22 into the outer
`end of the slot 26 between the clamping arms 24.
`The clamping arms 24 have inner surface portions
`between the inner end of the slot 26 and their free ends
`46, preferably generally adjacent their free ends, that
`define the first (wide) position 28. And the inner end of
`the slot 26 may be, for example, generally adjacent the
`second position 30 as shown in FIGS. 2-4, with a por-
`tion of the clamping arms 24 generally adjacent the
`bridging portion 44 defining an open area as the second
`(narrow) position. The slot 26 defines the longitudinal
`direction or axis of the clamp 20.
`Abutment means, such as ledges 40 and 41 extending
`laterally outwardly from opposite sides of the clamp 20,
`may be provided on the clamp 20. The ledges 40 and 41
`limit insertion of the clamp 20 into the elongate passage-
`way l8 to a first predetermined distance, with the first
`
`ACTA EX. 1018-006
`
`ACTA Ex. 1018-006
`
`

`
`5,017,192
`
`BEST AVAILABLE cosy
`
`6
`20, cassette and IV tubing 12 in the door assembly 16,
`and the knob 36 is turned to pull the door assembly 16
`toward the main body 38 of the pumping assembly 14.
`As the door assembly 16 moves toward the main body
`. 38 of the pumping assembly 14, the wedge 22 is forced
`between the clamping arms 24 of the clamp 20 to move
`them to the open position (FIG. 3) to permit fluid flow
`through the IV tubing 12 during operation of the pump
`10.
`
`In order to remove the IV tubing set from the pump
`10, the knob 36 is turned in the opposite direction to
`return the door assembly 16 to its loading and unloading
`position (FIG. 2), where it is spaced from the main body
`38 of the pumping assembly 14. The door 34 is then
`opened, and the IV tubing set, including the IV tubing
`12 and clamp 20, are removed from the infusion pump
`20, with the the lumen of the IV tubing 12 being closed
`_due to the clamping action of the clamping arms 24
`’ against the tubing 12 at the second position 28. As a
`result, free flow through the tubing 12 is prevented
`during and ‘after disconnection of the IV tubing set
`regardless of whether a standard roller clamp (not
`shown) is closed.
`_
`As various changes could be made in the above con-
`structions without departing from the scope of the in-
`vention, if is intended that all matter contained in the
`above description or shown in the accompanying draw-
`ing be interpreted as illustrative and not in a limiting
`sense.
`We claim:
`
`5
`and second positions 28 and 30 of the IV tubing 12 being
`spaced apart along the longitudinal axis of the clamp 12
`a second predetermined distance substantially equalto ,
`the first predetermined distance. In other words, the
`ledges 40 and 41 are preferably spaced from _the free
`ends 46 of the clamping legs 24 distance substantially ‘
`equal to the distance separating the first and second
`positions 28 and 30. And‘ the cassette-receiving block 32
`of the pumping assembly14 includes a wall 48 substan-
`tially preventing movement of the IV tubing 20 into the
`pas'sageway,18 as the clamp 20 is inserted into the pas-
`_ sageway 18 so that the IV tubing 18 is moved from the
`first position 28 to the secondposition 30 when the
`clamp 20 is manually inserted in the passageway 18 the
`first predetermined distance.
`A sensor_ 50 (FIGS. 2 and 3) may be provided to
`determine when the clamp 20 is fully inserted in pas—
`sageway I8, and the infusion pump 10 may include
`alarm circuitry responsive to the sensor 50, and may
`even be electrically disabled when the ‘sensor 50 fails to
`indicate a fully inserted clamp 20. The sensor 50 in-
`cludes a proximity switch 52 and a suitable linkage 54
`for tripping the proximity switch 52 when the clamp 20
`is fully inserted.
`FIG. 5 illustrates a second embodiment of a flexible
`‘H “clamp 20A, which incl_u_des two bridging portions 56
`joining the clamping arms 24A and defining opposite
`ends of the variable width slot 26A. The bridging por-
`tions 56 and/or clamping arms 24A are sufficiently
`flexible to permit the clamping arms 24A to be moved
`against the bias to their open position (FIG, 5) despite
`the addition of a second bridging portion 56. FIG. 5 also
`illustrates how a clamp-opening wedge 22A may be
`used with this alternative design. The wedge 22A
`would be driven into the slot 26A in the transverse
`direction (i.e., perpendicular to the sheet of the drawing
`in FIG. 5) to separate the clamping arms 24A.
`FIG. 6 illustrates another embodiment of the free
`flow prevention system wherein a pivotable arm 58 is
`provided for releasably retaining the flexible clamp 20B
`in the passageway 18B when the clamp 20B is inserted
`the first predetermined distance. The pivotable arm 58
`' is preferably pivotably mounted on the cassette-receiv-
`ing block 32B so that the arm 58 moves with the door
`assembly 16B. The door 34-B has a pivotable projecting
`portion 60 spring biased to a holding position (FIG. 6)
`for pressing or holding the pivotable arm 58 against the
`clamp 20B when the door 34B is moved to a closed
`position. And the projecting portion 60 is movable
`against the spring bias by the pivotable arm 58 when the
`clamp 20B is partially inserted in the passageway 18B
`and the door 34B is closed. This ability to move against
`the spring bias is believed‘ to prevent jamming of the
`door 34B when the clamp 20B is only partially inserted
`in the passageway 18B.
`The operation of the free flow prevention system will
`be described with respect to the embodiment shown in
`FIGS. 2-4. With the IV tubing 12 at the first (wide)
`position 28..in.the slot 26, the clamp 20 is moved longitu-
`dinally along;
`tubing; 15.2‘. to at
`agrpizopiziate for
`insertion otfbothe the tubing 12 and clamp; 202 into the
`infusion pump 10. The IV tubing 12,
`including the
`pumping, cassette, if any, and the clamp 20 are then
`manually placed or inserted into the cassette-receiving
`block 32 and the clamp-receiving passageway 18, with
`the IV tubing 12 moving to the second position 30 in the
`clamp’s slot 26 as the clamp 20 is inserted. The door 34
`of the door assembly 16 is then closed to hold the clamp
`
`.
`
`‘
`
`1. A free flow prevention system comprising:
`IV tubing having a lumen through which fluid may
`be pumped for administration to a patient;
`a pumping assembly including pumping means for
`pumping fluid through the IV tubing, and releas-
`able holding means for holding the IV tubing dur-
`ing operation of the pumping assembly;
`a fleiible clamp associated with the IV tubing and
`having a pair of clamping arms defining a variable
`width slot along which the IV tubing may be
`moved between a first position wherein the width
`‘of the slot is sufficient to permit the clamp to be
`positioned longitudinally along the IV tubing, and
`a second position wherein the width of the slot is
`normally less than the width of the slot at the first
`position, the clamping arms being resiliently biased
`to a closed position wherein the IV tubing is
`squeezed when in its second position to close the
`lumen to prevent fluid flow, the clamping arms
`being movable against the bias to an open position
`wherein the lumen of the IV tubing is allowed to
`open so that flow through the lumen is permitted;
`clamp-receiving means on the pumping assembly for
`releasably receiving the flexible clamp; and
`releasable clamp-opening means for separating the
`clamping arms of the flexible clamp and moving
`the arms from their closed position to the open
`position before operation of the pumping assembly;
`the clamp-receiving means and clamp-opening means
`being mounted on the infusion pump for movement
`of the clamp-opening means relative to the flexible
`clamp received in the clamp-receiving means be-
`tween an unloading position, wherein the clamp-
`opening means does not hold the arms of the flexi-
`ble clamp in their open position, and an operating
`position, wherein the clamp-opening means moves
`' the arms of the flexible clamp to their open position
`and holds the arms in the open position.
`
`ACTA EX. 1018-007
`
`55
`
`60
`
`ACTA Ex. 1018-007
`
`

`
`5,017,192
`
`25
`
`7
`2. A free flow prevention system according to claim
`1 wherein the clamp-opening means_ includes a wedge
`mounted on the pumping assembly for separating the
`clamping arms of the flexible clamp, the wedge and the
`flexible clamp being movable relative to oneanother
`between the operating position, wherein at least a por-
`tion of the wedge is positioned between the clamping
`arms to separate and hold the arms in their open posi-
`tion, and the unloading position, wherein the wedge is
`_not opening the clamping arms from their closed posi-
`tion so that the lumen-of the IV tubing is closed to fluid
`flow when the IV tubing is removed from the pumping
`assembly.
`3. A free flow prevention system according to claim
`2 wherein the clamp-receiving means is mounted or
`formed on the releasable holding means, and the releas-
`.able holding means is movable between a loading and
`unloading position, wherein the IV tubing may be
`loaded into or unloaded from the pumping assembly
`and the wedge and flexible clamp are in their unloading
`position, and the operating position wherein the flexible
`clamp is moved to the operating position relative to the
`'wedge and the clamp and IV tubing are held for opera-
`tion of the pumping assembly.
`4. A free flow prevention system according to claim
`2 wherein the flexible clamp has a bridging portion
`defining an inner end of the slot, the clamping arms of
`the clamp extending outwardly from the bridging por-
`tion and terminating in free ends that define the outer
`end of the slot, the free ends of the arms being tapered
`inwardly toward the slot and bridging portion to guide
`the wedge into the outer end of the slot between the
`clamping arms.
`5. A free flow prevention system according to claim
`4 wherein the clamping arms define a portion of the slot
`generally adjacent the inner end of the slot as the sec-
`ond position having a width normally less than the
`width of the slot at the first position, and the clamping’
`arms have portions generally adjacent their free ends
`that define an open area generally adjacent the free ends
`as the first position wherein the width of the slot is
`sufficient to permit the clamp to move longitudinally
`along the IV tubing.
`6. A free flow prevention system according to claim
`5 wherein the flexible clamp comprises a body formed
`of thermoplastic or synthetic resin material, and a resil-
`ient spring member biasing the clamping arms to their
`closed position.
`7. A free flow prevention system according to claim
`1 wherein the clamp-receiving means comprise walls in
`the releasable holding means defining an elongate pas-
`sageway having an open end for receiving the flexible
`clamp,
`the releasable holding means being movable
`between a loading and unloading position, wherein the
`IV tubing may be loaded into and unloaded from the
`pumping assembly, and an operating position, wherein
`the IV tubing is held for operation of the pumping as-
`sembly, the clamp-opening means being positioned in
`the elongate passageway such that. the clamping arms
`are
`fi.oinitlii:ii:'cll:-:saeiii' position to their open posi- 60
`tion when theereleasable holding means is moved to the
`operating position.
`8. A free fIow‘pres'ention_ system according to claim
`7 further comprising abutment means on the clamp for
`limiting insertion of the clamp into the elongate pas-
`sageway to a first predetermined distance, the slot of the
`flexible clamp defining a longitudinal axis of the clamp,
`with the first and second positions of the IV tubing
`
`_
`
`8
`being spaced apart along the longitudinal axis of the
`clamp a second predetermined distance substantially
`equal to the first predetermined distance, the pumping
`assembly including a wall substantially preventing
`movement of the IV tubing into the elongate passage-
`way as the flexible clamp is inserted into the elongate
`passageway so that the IV tubing is moved from the
`first to the second positions when the flexible clamp is
`inserted in the elongate passageway the first predeter-
`mined distance.
`
`9. A free flow prevention system according to claim
`_8 wherein the clamp-receiving means includes a pivot-
`able arm for releasably retaining the flexible clamp in
`the passageway when the clamp is inserted the first
`predetermined distance.
`10. A free flow prevention system according to claim
`9 wherein the releasable holding means of the pumping
`assembly includes a door having a pivotable projecting
`portion spring biased to a holding position for pressing
`or holding the arm against the flexible clamp when the
`door is moved to a closed position, the projecting por-
`tion being movable against the spring bias by the pivot-
`able arm when the clamp is partially inserted in the
`passageway and the door is closed to prevent jamming
`of the door when the clamp is only partially inserted in
`the passageway.
`11. A free flow prevention system according to claim
`10 wherein the IV tubing includes a pumping cassette
`having flexible walls defining fluid pumping chambers
`that may be compressed by the pumping means to regu-
`late fluid flow through the IV tubing, the door of the
`pumping assembly being adapted to hold the pumping
`cassette in the pumping assembly.
`12. A free flow prevention system according to claim
`10 wherein the flexible clamp includes two bridging
`portions joining the clamping arms and defining oppo-
`site ends of the variable width slot, the bridging por-
`tions and/or clamping arms being sufficiently flexible to
`permit the clamping arms to be moved against the bias
`to their open position.
`13. A free flow prevention system according to claim
`8 wherein the releasable clamp-opening means includes
`a wedge on the pumping assembly that separates the
`clamping arms of the flexible clamp when the releasable
`holding means of the pumping assembly is moved to its
`operating position such that the arms are held in their
`open position,
`the releasable holding means of the
`pumping assembly including a door having a projecting
`portion adapted for releasably retaining the flexible
`clamp in the elongate passageway when the clamp_is
`inserted the first predetermined distance and the door is
`moved to a closed position whereby the flexible clamp
`is held against longitudinal movement by the projecting
`portion when the wedge separates the clamping arms of
`the flexible clamp.
`regulating fluid flow
`14. An infusion pump for
`through a lumen of IV tubing to a patient and being
`adapted for use with a flexible clamp that prevents free
`flow of‘ the fluid through the IV tubing-after the tubing
`is disconnected from the infusion pump,
`the clamp
`being of the type having a pair of clamping arms defin-
`ing a variable width slot along which the IV tubing may
`be moved between a first position wherein the width of
`the slot is sufficient to permit the clamp to be positioned
`longitudinally along the IV tubing, and a second posi-
`tion wherein the width of the slot is normally less than
`the width at the first position, the clamping arms being _
`resiliently biased to a closed position wherein the IV
`
`ACTA EX. 1018-008
`
`ACTA Ex. 1018-008
`
`

`
`5,017,192
`
`9
`tubing is squeezed when in the second position to close
`the lumen to prevent fluid flow, the clamping arms
`being movable against the bias to an open position
`wherein the lumen of the IV tubing is allowed to open
`so that flow through the lumen is permitted; the infusion
`pump comprising:
`including pumping means
`a pumping assembly,
`adapted for pumping fluid through the IV tubing,
`and releasable holding means adapted for holding
`the IV tubing during operation of the pumping
`assembly;
`clamp-receiving means on the pumping assembly
`adapted for releasably receiving the flexible clamp;
`and
`
`releasable clamp-opening means adapted for separat-
`ing the clamping arms of the flexible clamp and
`moving the arms from their closed position to the
`_ open position before operation of the infusion
`Pl-“HP;
`the clamp-receiving means and clamp-opening means
`being mounted on the infusion pump for movement
`relative to one another between an unloading posi-
`tion, wherein the clamp—opening means does not
`hold the arms of a flexible clamp received in the
`"clamp-receivingmeans in their open position, and
`an operating positiongwherein the clamp-opening
`means_moves the arms of a flexible clampreceived
`in the clamp-receiving means to their open position
`and holds the arms in the open position.
`15. An infusion pump according to claim l4gwherein
`the clamp-receiving means further comprises walls’ in
`the pumping assembly defining a passageway having an
`open end adapted for releasably receiving the flexible
`clamp, and the clamp-opening means comprises a
`wedge mounted on the pumping assembly, the wedge
`and the walls being movable relative to one another
`between the operating position, wherein at least a por-
`tion of the wedge is positioned between the clamping
`arms of a flexible clamp received in the passageway to
`separate and hold the arms in thei