United States Patent
`
`[19]
`
`[11]
`
`4,308,865
`
`
`Hay
`[45]
`Jan. 5, 1982
`
`[54]
`
`INTERLOCK SYSTEM FOR ANESTHETIC
`VAPORIZERS
`
`778787
`1193522
`
`7/1957 United Kingdom ......... .. 123/203.25
`6/1970 United Kingdom ......... .. 128/203.28
`
`OTHER PUBLICATIONS
`_
`Ohio., Unitrol Anesthesia Machine, Airco Products
`Catalog Form No. 9906 (Rev. 1978).
`_
`_
`Primary Exammer-—-Henry J. Recla
`/Ciittornfiiy, Agent, or Firm——Roger M. Rathbun; Larry R.
`3556
`[57]
`ABSTRACT
`1
`
`A "aP°"Z‘:’ i‘.“e"°°k. “Ste”? is ‘“S°'°Se.d “’hi°h is “5.°d
`in an anest esia machine having two calibrated vaporiz-
`ers for providing an anesthetic toa patient and further
`having a selector valve with three positions, two ex-
`treme positions where one of the two Vaporizers is
`being utilized and a middle position where neither Va»
`porizer is used. The system prevents opening of either
`vaporizer when the selector valve is in the middle posi-
`tion_ A150’ when the selector valve is moved to one of
`its extreme positions selecting one of the vaporizers, the
`other vaporizer is prevented from being moved from its
`“off” position. The “on” vaporizer must thereafter be
`Placed in its “°fl"' P°5i‘i°“ befme the Select“ Val“ can
`be returned to its middle position In addition, a quick
`disconnect means is shown for quickly attaching and
`detaching the Vaporizers from the anesthesia machine.
`
`Inventor: Wayne W. Hay, Madison, Wis.
`[75]
`[73] Assignee, Airco, Inc" Momvale’ N_J_
`[21] Appl. No.: 86,386
`‘
`0¢t- 19; 1979
`[22] Filed!
`[51]
`Int. Cl.3 ..................... A61M 11/00; A61M 17/00
`[52] U.S. Cl. ........................ .. 128/200.14; 128/200.19;
`
`[58] Field of Search ...................... 128/200.1711,"/2231?,
`128/200.16, 200.17’ 20019’ 20021’ 203.12’
`203I14 20325 20328 204.13 204.14_
`’261/DIE} 65_ 7’4/483 lg 483 Ii
`'
`’
`’
`References Cited
`U.S_ PATENT DOCUMENTS
`
`[56]
`
`3/1914 Kelley ...................... .. 128/200.19 X
`5/1920 Cam" - - - - ‘
`‘ - ‘ - '‘' - ~ -' 74/483 R
`1; §
`74/483 R X
`9/1956 Mitcham
`2’764’182
`128/203.12
`8/1974 Needham ...........
`3:831:599
`4,058,120 11/1977 Caparrelli et al.
`............. 128/203.12
`FOREIGN PATENT DOCUMENTS
`
`
`
`1,090,863
`113402930
`
`255258 11/1912 Fed. Rep. of
`Germany ...................... .. 128/200.11
`
`3 Claims, 7 Drawing Figures
`
`001
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`PRAXAIR 1013
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`U.S. Patent
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`Jan.5, 1982 ‘
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`Sheet 1 554
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`U.S. Patent
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`Jan. 5, 1982
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`-U.S. Patent
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`Jan. 5, 1982
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`Sheet4 of4
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`4,308,865
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`1
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`INTERLOCK SYSTEM FOR ANESTHETIC
`VAPORIZERS
`‘
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`4,308,865
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`2
`vaporizer in use only by turning the selector valve
`toward that vaporizer and such vaporizer must thereaf-
`ter be turned to its off position before the selector valve
`can be returned to its middle position.
`‘
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention is diagrammatically illustrated, by way
`of example, in the drawings appended hereto, in which:
`“FIG. 1 is an isometric view of the interlock system
`constructed in accordance with the present invention;
`FIG. 2 is a plan view, partly in cross-section, depict-
`ing the interlock system with two vaporizers in posi-
`tion;
`FIG. 3 is a front view, partly in section, and showing
`one vaporizer partly cut away;
`\
`FIG. 4 is a side view, partly in section, showing the
`quick disconnect means for retaining a vaporizer;
`FIG. 5 is a front view of a latching ring, one of the
`components of the present interlock system;
`FIG. 6 is an isometric view of a pivot bracket, a
`component of the present interlock system; and
`FIG. 7 is an enlarged, cross-sectional view showing a
`spring biasing means used in the present invention.
`
`DESCRIPTION OF PREFERRED EMBODIMENT
`
`Turning first to FIG. 1, there is shown an isometric
`view of the interlock system made in accordance with
`the‘ present invention and used with an anesthesia ma-
`chine.
`
`As part of the anesthesia machine, only the essential
`-features of such machine needed to describe the present
`invention being shown, there is a manifold 10 which
`contains the necessary passageways for gases to be de-
`livered. The passageways themselves are not herein
`described as they do not form a part of this invention.
`The manifold 10 does provide a mounting means for
`the vaporizers, however, and such means includes two
`pairs of pins 12 on which two vaporizers are mounted as
`will be later described. The manifold 10 also includes
`outlets 14 and inlets 16 which provide gas to and re-
`ceive anesthetic laden gas from the vaporizers when
`they are installed on manifold 10. A pair of screw holes
`18 are drilled in manifold 10 for use with screws (not
`shown) that retain the vaporizers securely in position
`when mounted for use on manifold 10. The afore de-
`scription applies to positions for mounting a vaporizer
`on both ends of manifold 10.
`.
`
`In the center of manifold 10, there is a provision for
`mounting a selector‘ valve to be later described. FIG. 1
`shows a plurality of holes 19 that are used to align with
`and provide gas passageways to such selector valve,
`however,
`the particular passageways, again, do not
`form a part of the present interlock system, except as to
`denote the particular position where the selector valve
`is mounted intermediate the mounting positions for the
`two vaporizers.
`On the top of manifold 10, there is mounted a pivot
`bracket 20, shown also in the isometric FIG. 6. The
`pivot bracket 20 may be fastened to the manifold 10 by
`means such as cap screws 22 (shown in FIG. 2) and
`which pass through holes 24in the pivot bracket 20. A
`further set of threaded holes 28 and 30 are formed in the
`pivot bracket 20 and will be later explained. The pivot
`bracket 20 has a recessed portion 32 and further has its
`front surface partially removed as slanted surfaces 34
`and 36. A pair of spring holes 38, 40 are formed on the
`inner surface of the recessed portion 32. As shown in
`
`5
`
`BACKGROUND OF, THE INVENTION
`This invention relates to an anesthesia machine, and
`more particularly, to an interlock system for use with ~
`two anestheticpvaporizers and which isputilized with a
`selector valve having three positions, i.e. two extreme
`positions, where one of the two vaporizers may be used, 10
`and a middle position where neither vaporizer can be
`used. The interlock system prevents the possibility of
`eithe vaporizer being in,the “on” position at any time
`when that vaporizer has not been selected to supply an
`anesthetic to a patient.
`Anesthesia‘ machines are relatively common in which
`one or more calibrated vaporizers are used to supply an
`anesthetic gas to a patient. Each vaporizer supplies a
`different anesthetic and can be selected by the user in
`accordance with the particular anesthetic chosen to be
`utilized.
`
`15
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`20
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`As a safety measure, it is advantageous to have some
`system whereby the operator cannot inadvertently turn
`both vaporizers on at one time, or turn on the wrong
`vaporizer when, in fact, he has not chosen to use that 25
`particular anesthetic.
`
`SUMMARY OF THE INVENTION
`
`35
`
`The invention comprises an interlock system wherein
`two calibrated vaporizers are mounted on a manifold of 30.-
`an anesthesia machine and a selector valve is located
`therebetween. The selector valve has three positions;
`two extreme positions where one of the two vaporizers
`may be used and a middle position wherein neither,
`vaporizer can be used.
`,The system includes a latching ring which rotates
`with the selector valve and has two recesses. A pair of
`latches, each pivotable about a point, allows each latch
`to ‘pivot between a first and a second position. Each
`latch has one end thereof shaped such as to fit within 40
`only one of said two recesses. The latches ‘are biased
`towardtheir first position wherein the latches have
`their shaped ends fitted within their corresponding re-
`cess in the latching ring when the latching ring is in the "
`appropriate position. The other end of each of the 45
`latches is adapted, when in its second position, to physi-
`cally prevent opening of one of the vaporizers and can
`therefore only be in that second position when such
`vaporizer is in the “off” position.
`The latch ring has its recesses positioned such that 50
`when the selector valve is inpone of its extreme posi-
`tions, only one of the latches is movable into its first
`position, thereby allowing one of said vaporizers to be
`moved from its “off” position, while the other vaporizer
`must remain in its “off” position.
`In the middle position of the selector valve, both
`latches must be in their second position, that is when
`both vaporizers must be in their “off” positions and
`neither can be moved from that off position until the
`selector valve is moved to one of its extreme positions.
`In practice, the selector valve is movable to the right
`or’ clockwise towards the vaporizer mounted on the
`manifold to the right of the selector valve,‘ such that the
`right hand latch moves to its first position, ‘thereby
`freeing that vaporizer to be moved to some position
`other than off. At such time, the left latch cannot move
`from its second position and thus the left vaporizer must
`remain in its off position. Thus the user can‘ put either
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`4,308,865
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`valve 86 directly to a patient and neither of the vaporiz-
`ers 66‘and 68 can be ‘used, both being in their “off”
`position.
`Basically selector valve 86 has a handle 88 and which
`controls the position of a rotor 90. The rotor 90 is mov-
`able to and away from manifold 10 and is spring biased
`to its position shown in FIG. 2, that is, toward manifold
`10. A pin 92, two of which are normally used 180° apart,
`is adapted to fit within one of the three recesses 94, 96
`and 98 formed in rotor 90. Intermediate the recesses 94,
`96 and 98 are V-shaped cams 100 and 102.
`In FIG. 2, the selector valve 86 is in its middle posi-
`tion where pin 92 is fitted within recess 96. As the han-
`dle 88 is pulled away from manifold 10 against the
`springibias, the rotor 90 may be turned to either of two
`extreme positions, one of which is clockwise wherein
`the pin 92 can fit within recess 94. In such position,
`where the rotor 90 is moved clockwise to its extreme,
`position to the right, the right Vaporizer 66 is placed in
`the flow of gas to a patient and thus, when opened, is
`operative‘. Similarly, rotor 90 can be turned to its ex-
`treme left position, where pin 92 fits within recess 98,
`thereby enabling the left vaporizer 68 to be used to
`provide anesthetic to the patient.
`Depending outwardly from rotor 90 are a pair of ears '
`104, 106 (seen in FIGS. 2 and 3) each of which have
`holes 108, 110. In sliding engagement within holes 108
`and 110, are pins 112 and 114, respectively, and which
`pins 112 and 114 depend outwardly from a latching ring
`116. The latching ring 116 is held in close proximity to
`the manifold 10 by means of retaining ring 118. Accord-
`ingly, as the rotor 90 is moved laterally away from the
`manifold 10 to rotate the rotor 90 to another selected
`position, ears 104 and 106 move along pins 112 and 114
`such that the latching ring 116 does not move laterally
`with rotor 90, but does rotate therewith as rotor 90
`rotates.
`‘
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`FIG. 7, which is an enlarged! cross-sectional view show-
`ing the purpose of spring holes 38 and 40, a spring 42 is
`located in each of the spring holes 38 and 40. Only the '
`spring hole 38 is shownin FIG. 7, however, the func-
`tions of the spring holes 38 and 40 are identical.
`In both instances the springs 42 exert a bias against
`latches 44 and 46. As shown in FIG. 1, each of the
`latches 44 and 46 ‘are pivoted about pivot screws 48, 50
`and both latches 44 and 46 have a blocking extension 52
`and 54 that extend generally parallel to the manifold 10.-
`In addition, both of the latches 44 and 46 have, at
`their other ends, tips 56, 58'which project downwardly
`and have beveled surfaces 60, 62. One of the latches 46
`also includes a recess 64 which affords room for mount-
`ing a vaporizer in that position as will be later seen.
`The latch 44 is also shown in a dotted line position in
`FIG. 1 where it has pivoted about its pivot screw 48 to
`a position in which the blocking extension 52 is dis-
`placed counterclockwise about pivot screw 48, moving
`the blocking extension 52 backwardly, while at the
`same time moving tip 56 forwardly. The dotted line
`position is the position toward which spring 42 continu-
`ally biases the latch 44, and, absent some other con-
`straints preventing such movement, it is the position the
`latch 44 would normally occupy. It may also be seen
`that the same biasing is continually applied to latch 46
`even though a dotted line position is not illustrated with
`respect to latch 46.
`Turning now to FIG. 2, there is shown a plan View of
`the interlock system‘ used with a right vaporizer 66 and
`a left vaporizer 68 screwed in their operational position
`on manifold 10. In most respects, the Vaporizers 66 and
`68 operate in conventional manner, however, both are
`shown in their “off” position. To operate either vapor-
`izer 66 or 68, their control knobs 70 and 72 are rotated
`counterclockwise from the position shown in FIG. 2.
`The Vaporizers 66 and 68 are mounted on manifold 10
`in a manner such as to provide accurate positioning, yet
`afford ready connection and disconnections. A_ vapor-
`izer bracket 74 is L-shaped having one leg thereof af-
`fixed to the vaporizer and an outwardly depending leg
`76 having two holes 78 and 80. The holes 78 and 80 are
`each formed of two circular openings of dissimilar di-
`ameter slightly overlapped. In mounting the vaporizer
`66, the lrger diameter openings are slipped over pins 12
`and as the vaporizer 66 is rested against manifold 10 by
`its own weight, the pins 12 slip into the smaller diameter
`openings, thereby firmly holding the vaporizer 66 in a
`cantilever fashion. The same mounting procedure is
`used with respect to vaporizer 68.
`A further feature of the Vaporizers 66 and 68 is the
`presence of locking flanges 82 and 84. In the FIG. 2,
`each of the locking flanges 82 and 84 are shown en-
`gaged by the blocking extensions 52 and 54, respec-
`tively, so that the Vaporizers 66 and 68, being in their
`closed positions, cannot have their control knobs 70 and
`72 rotated counterclockwise and thus cannot be rotated
`from the “off” position.
`A selector valve 86 is located intermediate the right
`vaporizer 66 and the left vaporizer 68. The details of the
`selector valve 86 as to its flow paths and the like do not ,
`form part of this invention and hence will not be herein
`detailed, however, the basic outline of its operation will
`be described inasmuch as it is adapted to be placed into
`any one of three operating positions, two extreme posi-
`tions wherein one of the Vaporizers 66 or 68 may be
`utilized to provide an anesthetic to a patient, and a
`middle position wherein gas passes through the selector
`
`In FIG. 5, there is a view of the face of the latching
`ring 116 that faces the manifold 10. The latching ring
`116 has a pair of grooves seen Viewing the manifold .10
`from the front and identified as right groove 120 and left
`groove 122 and which are cut into the surface of the
`latching ring 116, and are specially designed such that
`only tip 56 of latch 44 fits into left groove 122 and only
`tip 58 of latch 46 can fit within right groove 120 of
`latching 116 when such latch is aligned with the corre-
`sponding groove.
`In operation, therefore, again taking FIGS. 2 and 3, in
`the middle position of selector valve 86, neither of the
`tips 56 and 58 are in alignment with either of the right
`groove 120 or left groove 122 and therefore the latches
`44’ and 46 cannot be pivoted from their position as
`shown. In such position, both the right vaporizer 66 and.
`the left vaporizer 68 must be in the closed position and
`their control knobs 70 and 72 cannot be rotated to the
`open position, since blocking extensions 52 and 54 pre-
`vent such movement by blocking, respectively, locking
`flanges 82 and 84.
`_
`.
`In the event an operator desires to utilize the right
`vaporizer 66, the selector valve handle 88 is turned to
`the right, clockwise. As the handle 88 turns, latching
`ring 116 movescorrespondingly until the left groove
`122 reaches a position in alignment with the latch 44.
`Since latch 44 can enter left groove 122, it pivots about
`pivot screw 48 whereby its tip 56 enters left groove 122.
`The latch 44 moves to its dotted line position of FIG. 1,
`thereby freeing the blocking extension 52 from its posi-
`tion impeding movement of control knob 70 of the right
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`return to the manifold 10 through Vaporizer outlet (not
`shown).
`It will be understood that the scope of the method
`and product of this invention is not limited to the partic-
`ular steps or materials disclosed herein, by way of exam-
`ple, but only by the scope of the appended claims.
`I claim:
`
`1. An anesthesia machine having an interlock system,
`said anesthesia machine comprising a manifold, first and
`second anesthetic Vaporizers mounted on said manifold,
`each of the Vaporizers including control means rotat-
`able to open and closed positions, a selector Valve
`mounted on said manifold intermediate the first and
`second Vaporizers, said selector Valve having first and
`second extreme position wherein said first and second
`Vaporizers, respectively, are operable, and said selector
`valve having a’ middle position wherein neither of said
`first and second Vaporizers is operable, said interlock
`system mounted on said manifold and comprising means
`to prevent rotation of said control means toward the
`open position of the first vaporizer when said selector
`Valve is in said second extreme position, and to prevent
`rotation of said control means toward the open position
`of said second vaporizer when said selector valve is in
`said first position and to prevent rotation of both con-
`trol means‘ of said first and second Vaporizers toward
`the open positions when said selector valve is in said
`middle position.
`2. An anesthesia machine as defined in claim 1
`wherein said means to prevent opening of said first and
`second Vaporizers comprises two pivotable latch means,
`each having first and second positions and each adapted
`to physically block, when in their second position, rota-
`tion of one of said control means of said first and second
`Vaporizers and said interlock system further includes
`means to allow and prevent movement of said pivotable
`latches to the first and second positions.
`3. An anesthesia machine as defined in claim 2
`wherein both of said pivotable latches are biased toward
`their first position, and said means to allow and prevent
`movement of said pivotable latches to the first and sec-
`ond positions comprises a latching ring movable with
`said selector Valve and having two recesses, each of said
`latches being movable individually to its first position
`when said latch is aligned by movement of said selector
`valve in predetermined position with respect to one of
`said two recesses such that said latch enters said aligned
`recess.
`in
`1:
`t
`at
`at
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`5
`vaporizer 66. The right vaporizer 66 can therefore be
`opened for use, yet latch 46 cannot move from its posi-
`tion blocking movement of the control knob 72 of the
`left vaporizer 68 and therefore such Vaporizer must
`remain in the “off” position.
`When the operator no longer desires to use the right
`vaporizer 66 and therefore intends to move the rotor 90
`of selector Valve 86 back to its middle position, the tip
`56 cannot be removed from the left groove 122, it being
`held flrmly within groove 122 by latch 44 since the
`blocking extension 52 rides on the outside surface of
`locking flange 82. The right Vaporizer 66 must, there-
`fore, be turned to the closed position, as shown in FIG.
`2, before the selector valve 86 can again be returned to
`its middle position. When right Vaporizer 66 is in the
`closed position, the latch 44 has its tip 56 held in left
`groove 122 only by means of the bias of spring 42 and
`by providing a slight beveled surface 57 on the latch tip
`56, (FIG. 1) the edge of the left groove 122 forces the
`beveled surface 57 against the spring bias and the selec-
`tor Valve 86 can be turned to the middle position.
`Obviously,
`the locking action has been described
`with respect to closing the right vaporizer 66, however,
`it may readily be seen that the same locking feature is
`provided with respect to selection of the left vaporizer
`68.
`
`In FIG. 4, a side view is provided showing a profile
`of an engagement between the locking flange 82 and the
`blocking extension. 52 of latch 44.
`In addition, FIG. 4 shows the quick connect and
`disconnect mounting means for the right vaporizer 66.
`As seen in FIG. 4, the right vaporizer 66 is hung from
`pins 12 which insert into the outwardly depending leg
`76 of the Vaporizer bracket 74. In such position, the
`right Vaporizer 66 hangs cantilever fashion and its
`weight forces its inlet and outlet, only one of which is
`shown in the figure as Vaporizer inlet 124 against the
`corresponding opening (outlet 14 as seen in FIG. 1) in
`manifold 10. A flexible grommet 126 in the Vaporizer
`inlet 124 seals against manifold 10, thus providing a
`sealed passageway for gas to pass to and from the mani-
`fold 10. The right vaporizer 66 can further be held in
`position by cap screw 128 fitted through a correspond-
`ing hole 130 in manifold 10 and threaded into internal
`threads in the Vaporizer bracket 74.
`Thus, only one cap screw 128 holds the right vapor-
`izer 66 in its position upon manifold 10 and the weight
`of the vaporizer forms sealed passageways for gas to
`flow from the manifold 10 to the vaporizer inlet 124 and
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