(12) United States Patent
`Palatnik et al.
`
`111111111111111111111111111111111111111111111111111111111111111111111111111
`US006654621B2
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,654,621 B2
`Nov. 25, 2003
`
`(54) FINGER OXIMETER WITH FINGER GRIP
`SUSPENSION SYSTEM
`
`(75)
`
`Inventors: Sam Palatnik, Glendale, WI (US);
`Dave Donars, New Berlin, WI (US);
`Robert Rammel, Muskego, WI (US)
`
`(73) Assignee: BCI, Inc., Waukesha, WI (US)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/940,418
`
`(22) Filed:
`
`Aug. 29, 2001
`
`(65)
`
`Prior Publication Data
`
`US 2003/0045784 A1 Mar. 6, 2003
`
`Int. Cl? .................................................. A61B 5/00
`(51)
`(52) U.S. Cl. ....................... 600/322; 600/323; 600/340;
`600/344
`(58) Field of Search ................................. 600/322, 323,
`600/340, 344, 485, 490, 499
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`8/1987 Goldberger et a!.
`4,685,464 A
`4/1989 Frick eta!.
`4,824,242 A
`4,825,872 A * 5/1989 Tan et a!. . . . . . . . . . . . . . . . . . . . 600/344
`5,035,243 A * 7/1991 Muz .............. o •• o •• o •••••• 600/344
`5,111,817 A
`5/1992 Clark eta!.
`5,247,931 A
`9/1993 Norwood
`5,311,865 A
`5/1994 Mayeux
`5,313,940 A
`5/1994 Fuse eta!.
`5,339,810 A
`8/1994 Ivers eta!.
`5,438,986 A
`8/1995 Disch eta!.
`5,490,523 A
`2/1996 Isaacson et a!.
`5,551,423 A
`9/1996 Sugiura
`5,676,139 A
`10/1997 Goldberger et a!.
`5,788,634 A
`8/1998 Suda eta!.
`5,792,052 A
`8/1998 Isaacson et a!.
`5,800,349 A
`9/1998 Isaacson et a!.
`5,810,724 A
`9/1998 Gronvall
`
`11/1998 Nierlich et a!.
`12/1998 Swedlow et a!.
`12/1998 Larsen eta!.
`9/1999 Terasawa et a!.
`10/1999 Merchant et a!.
`11/1999 Mannheimer et a!.
`11/1999 Kinast
`12/1999 Levin
`3/2000 Weckstrom et a!.
`4/2000 Ott eta!.
`7/2000 Lisiecki
`9/2000 Chin
`11/2000 Kiani-Azarbayjany et a!.
`11/2000 Miura eta!.
`12/2000 Larsen eta!.
`1!2001 Delonzor et a!.
`1!2001 Bindszus et a!.
`1!2001 Schollermann et a!.
`5/2001 Potratz
`5/2001 Asada eta!.
`
`5,839,439 A
`RE36,000 E
`5,842,981 A
`5,957,840 A
`5,961,450 A
`5,995,856 A
`5,995,858 A
`6,006,120 A
`6,041,247 A
`6,045,511 A
`6,083,156 A
`6,115,621 A
`6,151,516 A
`6,154,667 A
`6,163,715 A
`6,173,196 B1
`6,178,343 B1
`6,181,959 B1
`6,226,539 B1
`6,236,037 B1
`* cited by examiner
`Primary Examiner--Eric F. Winakur
`Assistant Examiner-David 1. McCrosky
`(74) Attorney, Agent, or Firm-Louis Woo
`
`(57)
`
`ABSTRACT
`
`A finger oximeter has a fixed first finger grip member and a
`second finger grip member that is movable relative to the
`first fixed finger grip member. The finger grip members are
`mounted to a casing, with the first finger grip member being
`fixedly coupled to a top portion of the casing and the second
`finger grip member being movable vertically within the
`casing. A force is continuously applied against the movable
`finger grip member to bias it towards the fixed finger
`gripping member. This biasing force has sufficient yield so
`that when a finger is inserted between the two finger grip
`members, the movable finger grip member would yield to
`the incoming finger. At the same time the biasing force is of
`a sufficient magnitude to push the movable finger grip
`member towards the fixed finger grip member to effect a firm
`grip of the finger. The biasing force is evenly distributed to
`the movable finger grip portion to effect a floating finger grip
`suspension system for the finger oximeter.
`
`30 Claims, 3 Drawing Sheets
`
`22£ 22g
`
`Apple Inc.
`APL1198
`U.S. Patent No. 9,289,135
`
`001
`
`

`

`U.S. Patent
`
`Nov. 25, 2003
`
`Sheet 1 of 3
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`US 6,654,621 B2
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`Nov. 25,2003
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`

`US 6,654,621 B2
`
`1
`FINGER OXIMETER WITH FINGER GRIP
`SUSPENSION SYSTEM
`
`FIELD OF THE INVENTION
`
`The present invention relates to finger oximeters and more
`particularly to a finger oximeter having a suspension system
`that enables the finger gripping portions of the oximeter to
`firmly and evenly grasp a patient's finger.
`
`BACKGROUND OF THE INVENTION
`
`2
`portion with an even distribution of force along the length of
`the finger, to thereby cause the two finger gripping portions
`to firmly grasp the finger placed therebetween.
`The force applied against the movable finger gripping
`portion to bias it towards the fixed finger gripping portion is
`supplied by a plurality of coiled springs interposed between
`the movable finger gripping portion and a casing along
`which sidewalls the movable finger gripping portion guid(cid:173)
`ingly moves. The springs may be secured to ledges extend-
`10 ing from the lower portion of the respective sidewalls of the
`casing so that the biasing force is applied against the
`movable finger gripping portion in such a way that the
`movable finger gripping portion is movable vertically with
`respect to the fixed finger gripping portion.
`The fixed finger gripping portion may be mounted to the
`upper part of the casing, and is configured such that its upper
`surface is adaptable to receive a printed circuit board that has
`mounted thereto or etched thereon a number of electronic
`components or circuits that effect the operation of the finger
`oximeter. A display, LED or otherwise, is also mounted to
`the PC circuit board for displaying values that represent the
`physical parameters of the patient measured via the patient's
`finger.
`The finger gripping portions are further configured to
`have respective apertures through which light from a light
`emitter may be directed from one of the finger gripping
`portions to a corresponding aperture of the other finger
`gripping portion, which is equipped with a receptive pho-
`30 todetector.
`To power the finger oximeter of the instant invention, a
`battery pack or module is mounted to the underside of the
`movable finger gripping portion so as to move in unison with
`the movable finger gripping portion. To operate, a user needs
`to manually activate a switch mounted to the casing. To
`conserve energy, the device is automatically turned off after
`a predetermined time period, if it no longer is in use.
`It is therefore an objective of the present invention to
`provide a finger oximeter that has a floating suspension
`40 system.
`The finger oximeter of the instant invention has the
`further objective of evenly distributing the gripping force
`applied by its finger gripping portions to the being gripped
`finger.
`
`45
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`There are a number of known finger oximeters. Generally,
`these finger oximeters are pulse oximetry units that utilize a
`sensor, and a coacting photodetector that detects the light 15
`emitted by the sensor, for determining the blood oxygen
`saturation of the arterial blood passing through the finger of
`a subject. To illuminate the finger of the subject, and to
`detect the light passing through the subject's finger, a prior
`art finger oximeter usually would have a finger gripping 20
`mechanism that has two finger gripping portions. The prior
`art teaches that these finger gripping portions hingedly coact
`with each other, usually by pivots. The following U.S.
`patents specifically disclose finger gripping portions that
`open to accept a finger via some hinge mechanism that 25
`enables the finger gripping portions of the finger oximeter to
`pivot about one end point of the finger oximeter: U.S. Pat.
`Nos. 4,685,464; 5,490,523; 5,792,052; 5,313,940; 5,676,
`139; 5,810,724; 5,957,840; and 6,041,247.
`There are other methods of enclosing two finger gripping
`portions about a finger. One such method is the taping of a
`finger to a photodetector by means of a tape that has a light
`emitter, as disclosed in U.S. Pat. No. 5,209,230. Another
`method clamps two finger gripping portions together by
`means of coacting teeth at the respective sidewalls of the 35
`finger gripping portions. This is disclosed in U.S. Pat. No.
`5,339,810. The use of a single piece U-shaped flexible
`holder that expands with the insertion of a finger is disclosed
`in U.S. Pat. No. 5,311,865.
`For those finger oximeters that use two piece finger
`gripping portions which are tightened by coacting grasping
`teeth at their respective sidewalls, there is the disadvantage
`that it is difficult to remove the finger from the finger
`gripping portions since the finger gripping portions are
`locked at a given dimension. And for those finger oximeters
`that utilize a hinged pivoting mechanism, the force that the
`finger gripping portions applies to a finger tends to be
`uneven along the finger, and gets weaker the further the
`finger is away from the hinged location.
`
`SUMMARY OF THE PRESENT INVENTION
`
`55
`
`The present invention finger oximeter has a floating
`suspension system that results from one of the finger grip(cid:173)
`ping portions being movable vertically relative to the other
`finger gripping portion, which is fixed. A biasing force is
`applied against the movable finger gripping portion so that
`the movable finger gripping portion is constantly biased
`towards the fixed finger gripping portion. The two coacting
`finger gripping portions are configured such that their oppos- 60
`ing surfaces are contoured to form an opening for accepting
`a finger inserted therebetween. The biasing force applied
`against the movable finger gripping portion is such that the
`movable finger portion is yieldable when a finger is inserted
`between the fixed and movable finger portions, and yet at the 65
`same time has a sufficient large biasing force to push the
`movable finger portion towards the fixed finger gripping
`
`The above-mentioned objectives and advantages of the
`instant invention will become apparent and the invention
`itself will be best understood by reference to the following
`50 description of an embodiment of the invention taken in
`conjunction with the accompanying drawings, wherein:
`FIG. 1 is a perspective drawing that shows various
`components of the finger oximeter of the instant invention
`being in various superposed positions;
`FIG. 2 is a perspective view illustrating the various
`components shown in FIG. 1 as well as the coil springs, the
`casing and the cover of the device being in alignment with
`each other;
`FIG. 3A is a top view of an assembled device of the
`instant invention;
`FIG. 3B is a front view of the finger oximeter of the
`instant invention that shows the opening through which a
`finger may be inserted between the two finger gripping
`portions of the device;
`FIG. 3C is a back view of the finger oximeter of the
`instant invention;
`
`005
`
`

`

`US 6,654,621 B2
`
`3
`FIG. 3D is a side view of the FIG. 3A device; and
`FIG. 4 is an electrical schematic of the finger oximeter of
`the instant invention.
`
`DETAILED DESCRIPTION OF 1HE
`INVENTION
`With reference to FIG. 1, the finger oximeter of the
`present invention is shown to include a lower finger grip
`portion 2 and an upper finger grip portion 4. Fitted to lower
`finger grip portion 2 and upper finger grip portion 4 are
`lower finger pad 6 and upper finger pad 8, respectively. The
`lower and upper finger grip portions, as well as their finger
`pads, are configured to conform to the shape of a human
`digit, such as for example a finger. This is best illustrated by
`the lower surface of finger pad 6 and the upper surface of
`finger pad 8, which are opposed to each other. Thus, once the
`respective finger pads 6, 8 are attached to their correspond(cid:173)
`ing finger grip portions 2, 4, an opening 10, best shown in
`FIGS. 2 and 3B, is provided when finger grip portions 2 and
`4 are positioned adjacent to each other.
`As best shown in FIG. 1, lower grip finger portion 2 is an
`elongate member that has two sides 2s extending from a base
`2b. A space or void 2v is provided at approximately the
`center of base 2b onto which a photodetector 18 (D1 in FIG.
`4) may be positioned. The front end of base 2b is curved for 25
`forming one portion of opening 10. The back end of elongate
`member 2 has a backstop 2bs that is configured to receive,
`in a sliding engagement fashion, a battery module 10.
`Although not shown, battery module 10 is configured to
`enable the insertion of two batteries thereinto for providing
`power to the electronic components shown in FIG. 4 to
`thereby energize the finger oximeter, whose operation will
`be discussed later. A spring -like conductor 12 inserted to
`battery module 10 connects in series the batteries, thereby
`increasing the available voltage.
`Each of sidewalls 2s of elongate member 2 further has
`extending therefrom at least two ears, or catches 2cl (2cl')
`and 2c2 (2c2'). The purpose of catches 2c will be discussed
`with reference to FIG. 2.
`Lower finger pad 6, which may be made of a rubbery
`material that is not compliant, is attached to base 2b of finger
`grip portion 2. In addition to finger pad 6, a conductive strip
`14 is inserted to the back end of finger grip portion to
`provide an electrical path for the power supplied by battery 45
`module 10. Connected to conductive end 14 is a flexible
`strip 16 which has attached thereto photodetector 17. With
`photodetector 17 resting in space 2v of elongate member 2
`and with finger pad 6 placed thereover, photodetector 17 is
`exposed, and is therefore adaptable to receive light directed
`thereto, per aperture 6a of finger pad 6. As can be seen,
`finger pad 6 is configured, per its arcuate interior surface, to
`conform partially to the shape of a human finger.
`Upper finger grip portion 4, which is also configured in
`the form of an elongate member, has attached to its under(cid:173)
`side finger pad 8, which is curved in an opposing manner to
`finger pad 6 and contoured to partially conform to the shape
`of a finger. Finger pad 8, also made of a non-compliant
`rubber material, may be attached to the lower surface of
`elongate member 4 by glue or other adhesive means, which 60
`is similar to the way by which finger pad 6 is attached to
`elongate member 2. Once attached, aperture Sa of finger pad
`8 is aligned with aperture 4a of elongate member 4.
`Elongate member 4 has two sides 4s extending upwards
`from its base 4b to form a semi-closed enclosure at its upper 65
`surface for accepting a printed circuit board or module 19.
`Although not shown clearly, mounted to module 19 are a
`
`30
`
`4
`number of electronic components, the circuitries of which
`are shown in detail in FIG. 4. Extending from each side 4s
`of elongate member is an extension 4e that has two fingers
`4f pointing downwards. The purpose of extensions 4e will be
`discussed with respect to FIG. 2. Also mounted to module 19
`is a display 20 that includes a number of digits for displaying
`information that corresponds to the physical parameters of a
`patient, such as for example the blood oxygen saturation of
`arterial blood, as measured from the patient's finger being
`10 inserted between finger grip portions 2 and 4. To effect the
`measurement of the physical attribute of the patient, a light
`source, such as for example a light emitting diode, is
`mounted to the underside of module 19 to be in alignment
`with aperture 4a of elongate member 4. The power provided
`15 to module 19 comes from the flexible conductive strip 16.
`With reference to FIG. 2, the various components illus(cid:173)
`trated in FIG. 1 of the finger oximeter of the instant
`invention are shown as having been assembled, with upper
`finger grip portion 4 being adjacent to lower finger grip
`20 portion 2. As was mentioned previously, when in such close
`contact, opening 10 is formed at the front of the two finger
`gripping members. It is through this opening that a finger is
`placed between the finger grip portions 2 and 4.
`As further shown in FIG. 2, the in contact finger grip
`portions 2, 4 are superposed over a casing 22, which has the
`form of aU-shaped skirt. Casing 22 has a back wall22b and
`two sidewalls 22s. Extending from the lower portion of
`sidewalls 22s are respective ledges 22/. In the inside of the
`respective sidewalls 22s are receptacles 22r, which are
`configured to receive fingers 4f of extension 4e of upper
`finger grip portion 4. Upon insertion of fingers 4f to recep(cid:173)
`tacles 22r, finger grip portion 4 is fixedly coupled to the top
`or upper part of casing 22. An adhesive may be used to
`further ensure that upper finger grip portion 4 is fixedly
`coupled to casing 22.
`At the two distal ends of sides 22s there are formed
`respective gripping edges or fingers 22g. Formed at the
`respective ledges 22/ are a number of fingers or extensions
`40 22e that provide the respective anchors each for securely
`receiving a corresponding spring 24. As shown, there are
`four springs 24, each securedly anchored by one of the
`extensions 22e at one corner of casing 22. Springs 24 may
`each be conventional compression coil springs.
`As further shown in FIG. 2, once anchored to extensions
`22e, when lower finger grip portion 2 is inserted to casing
`22, each of catches 2c in the form of ears extending from
`sidewalls 2s of elongate member 2 catches and presses down
`on a corresponding spring 24. Springs 24 are chosen to have
`50 a given elasticity so that, in combination, those springs
`provide a biasing force against elongate member 2 in an
`upwards direction, with reference to upper finger grip por(cid:173)
`tion 4, which is fixedly attached to the upper part of casing
`22. Thus, once elongate member 4 is fixedly coupled to
`55 casing 22, elongate member 2 nonetheless remains movable
`relative to elongate member 4, and is guidedly movable
`along the respective sidewalls 22s of casing 22.
`Given the fact that elongate member 2 is supported by
`independent springs 24 at different locations along its side(cid:173)
`walls 2s, when a finger is inserted to opening 10, although
`giving way to the finger, the biasing force exerted by springs
`24 would act against elongate member 2 vertically so as to
`firmly bias elongate member 2 against the inserted finger, to
`thereby firmly grip the inserted finger against fixed elongate
`member 4. Further, by providing springs 24 at the four
`corners of elongate member 2, a four point suspension
`system is effected to evenly distribute across elongate mem-
`
`35
`
`006
`
`

`

`US 6,654,621 B2
`
`5
`ber 2 the biasing force. Accordingly, a finger gripped by
`elongate members 2 and 4 is gripped evenly along its length.
`Furthermore, by hiding the springs at the respective corners
`of casing 22 and elongate member 2 so that no support base
`is required for elongate member 2, the respective sizes of the
`case 22 and elongate member 2 could be reduced, thereby
`leading to a reduction in the size of the entire device. So, too,
`by hiding the springs between the respective sidewalls of
`casing 22 and elongate member 2, the springs are sealed
`from dirt and isolated from potential mechanical abuse.
`Although only four springs are shown in the being dis(cid:173)
`cussed embodiment, it should be appreciated that a three
`spring configuration, with one spring at each sidewall and
`one spring at the back wall of casing 22 may also be used.
`Conversely, a greater number of springs, with more than two 15
`springs along each sidewall of casing 22, may also be used
`in other embodiments of the instant invention.
`To complete the assembled device of the instant
`invention, a filtered cover 26 that allows the digits to be seen
`from display 20, is placed over elongate member 4 so as to 20
`be fixedly coupled either to elongate member 4 or to the
`upper edges of casing 22.
`With reference to FIGS. 3A-3D, different views of the
`
`6
`particular, circuit 34 mounted on the flexible strip is con(cid:173)
`nected to functional circuit 36, which is an analog detector
`pre-conditioning circuit. As shown, the input electrical cur(cid:173)
`rent signal measured from the finger of the patient is sent to
`an op amp U2A, where the analog current signal is con(cid:173)
`verted to an analog voltage signal. The analog voltage signal
`is amplified by op amp U2C to output an amplified analog
`voltage signal VSIG. The dynamic range of the signal is
`controlled by IC circuit U4, which in essence is an integrated
`10 digital potentiometer.
`The amplified analog voltage signal VSIG is input to
`microprocessor U1 at inputA2. This analog voltage signal is
`converted by microprocessor U1 to a corresponding digital
`signal and output to circuit 3S, which is a LED driver circuit
`comprising driver IC circuits US and U9. The driver circuit
`3S provides the signal to the various digits DIG1-DIG6 for
`displaying the information collected from the patient on
`display 20.
`Another major functional component of the circuitry of
`FIG. 4 includes circuit 40, which is a variable LED driver
`circuit that drives the two LEDs that emit the light directed
`to the finger of the patient through apertures 4a and Sa of the
`upper finger grip portion and the upper finger pad S, respec(cid:173)
`tively. The light, after diffusing through the finger of the
`patient, is sensed by photodetector D1 (1S), which in turn
`outputs the resulting current signal to analog detector pre-
`conditioning circuit 36.
`Sub-circuit 44 of the FIG. 4 circuitry is a switching power
`supply circuit that regulates the power to be supplied to the
`various components of the FIG. 4 circuitry.
`Circuit 46 is a battery measurement voltage divider circuit
`that identifies when the voltage from battery pack 10 is low.
`Circuit 4S is a timing circuit for the components of the
`finger oximeter of the instant invention. A clock pulse is
`generated from circuit 4S for microprocessor U1 by com(cid:173)
`ponent U6A. Components U6B and U6C in combination
`ensure that there is enough voltage from battery pack 10 if
`the voltage output is less than 3 volts, so that the appropriate
`clocking signals are provided for the various components of
`the circuitry of FIG. 4.
`The present invention is subject to many variations,
`modifications and changes in detail. For example, instead of
`springs 34 being anchored to extensions 22e of ledges 22/ of
`casing 22, the biasing mechanism for lower grip portion 2
`could be an elastic one piece spring mechanism such as a
`leaf spring that biases elongate member 2 against the side(cid:173)
`walls 22s, and/or back wall22b of casing 22. To anchor such
`leaf spring to the casing, the ledges at the base of the casing
`50 may have to be expanded. So, too, could an elastic material
`such as rubber that has sufficient biasing characteristics be
`used to keep a force biasing movable elongate member 2
`towards fixed elongate member 4. Thus, it is intended that all
`matter described throughout this specification and shown in
`55 the accompanying drawings be interpreted as illustrative
`only and not in a limiting sense. Accordingly, it is intended
`that the invention be limited only by the spirit and scope of
`the hereto appended claims.
`What is claimed is:
`1. A finger oximeter, comprising:
`a casing having a back wall and two sidewalls each
`extending from said back wall;
`a first finger portion sandwiched by and movable verti(cid:173)
`cally along said sidewalls;
`a second finger portion in fixed relation with said casing
`to form an upper stop for the movement of said first
`finger portion;
`
`~~~~~es~~~~e: ~~::i~~ o;ft~ee i~::::~~~e~~~i~~s2~~:~h 25
`
`the digits displaying the blood oxygen saturation, and also
`the heart rate that may be obtained by measuring the
`physical attributes of a patient by means of her finger.
`FIG. 3B is a front view of the device showing opening 10 30
`through which the finger of a patient is inserted. As further
`shown, upper finger grip portion 4 is protected by cover 26
`so that only a portion thereof, and a portion of finger pad S,
`are shown. However, movable finger grip portion 2 is shown
`to be mounted within casing 22, with battery module 10 35
`removably coupled to the underside thereof. Movable finger
`grip member 2, which, in response to the bias force supplied
`by springs 24, is movable bidirectionally as indicated by
`directional arrow 30.
`FIG. 3C shows the back side of the finger oximeter of the 40
`instant invention. As shown, casing 22, or rather the back
`walls 22b thereof, has mounted thereto a switch 32, which
`enables a user to manually activate the device, i.e., by
`energizing the electronic components mounted to circuit
`board 1S. The back side of battery module 10 is also shown 45
`in FIG. 3C.
`FIG. 3D is a side view of device 2S of the instant
`invention which shows cover 26 attached to casing 22.
`Battery pack 10 is shown to form the bottom base of the
`device.
`FIG. 4 is a schematic of the electronic circuitry represen(cid:173)
`tative of the electronic components mounted to circuit board
`1S of the device. For ease of discussion, the various major
`functions of the circuitry of the instant invention device are
`separately grouped together by dotted lines. In particular, as
`shown in dotted box 34, a photodiode D1 (1S in FIG. 1) is
`mounted onto a flexible circuit support strip that is fitted to
`space 2v of lower grip member 2. Switch SW1, also
`mounted to and in electrical connection to the flexible circuit
`strip 34, when turned on by the user, causes light from the 60
`LED in circuit 40 to be directed to the finger placed between
`the finger grip portions 2 and 4. Once the finger is removed
`from the finger grip portions, microprocessor U1 is pro(cid:173)
`grammed to turn off device 2S after a predetermined time
`period, for example 8 seconds, so as to conserve energy.
`The photodetector and switch SW1 are connected to the
`main circuit by means of a conventional coupling. In
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`65
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`007
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`

`US 6,654,621 B2
`
`10
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`7
`wherein the respective surfaces of said first and second
`finger portions facing each other are configured to
`conform to a finger placed therebetween; and
`spring means provided at said casing for applying a
`biasing force against said first finger portion so that a
`finger placed between said first and second finger
`portions is firmly gripped by said first and second finger
`portions due to said first finger portion being biased by
`said spring means towards said second finger portion.
`2. Finger oximeter of claim 1, wherein each of said
`sidewalls of said casing comprises a ledge for forming a
`barrier to prevent said first finger portion from falling out of
`said casing, each of said sidewalls guiding the vertical
`movement of said first finger portion; and
`wherein said spring means comprises a plurality of
`springs at least two of which being secured to opposite
`ends of the ledge of each of said sidewalls for support(cid:173)
`ing and applying said biasing force vertically against
`said first finger portion.
`3. Finger oximeter of claim 1, further comprising:
`a printed circuit board having mounted thereon a plurality
`of electronic circuit components coupled to the top of
`said second finger portion, said second finger portion
`having an aperture for enabling the light from a light
`emitting source mounted to said circuit board to be
`directed toward said finger gripped by said first and
`second finger portions;
`a display mounted on top of said circuit board for dis(cid:173)
`playing at least readings of blood oxygen saturation of
`arterial blood measured from said finger; and
`a cover positioned over said display and fixedly coupled
`to either said second finger portion or the top of said
`casing.
`4. Finger oximeter of claim 3, further comprising:
`a battery module removably coupled to the underside of
`said fist finger portion for supplying power to said
`electronic circuit components and said display.
`5. Finger oximeter of claim 3, further comprising:
`a switch mounted to said casing to enable a user to 40
`manually activate said electronic circuit components.
`6. A pulse oximeter, comprising:
`a fixed portion;
`a non-fixed portion movable vertically relative to said 45
`fixed portion, said fixed and non-fixed portions in
`combination providing an opening through which a
`finger is insertable; arid
`means biasing against said non-fixed portion to apply a
`continuously distributed force against said non-fixed 50
`portion so that when a finger is inserted between said
`fixed and non-fixed portions, said non-fixed portion is
`movable vertically in a planar relationship to said fixed
`portion to accommodate but yet firmly grip said finger
`between said fixed and non-fixed portions.
`7. Pulse oximeter of claim 6, further comprising:
`a casing having two sidewalls extending from a back wall,
`said fixed portion being sandwiched by and in fixed
`relation with the upper parts of said sidewalls, said
`non-fixed portion being sandwiched by said sidewalls 60
`and movable vertically along the opposing surfaces of
`said sidewalls, respective ledges extending from the
`respective lower parts of said sidewalls forming a base
`support for said non-fixed portion.
`8. Pulse oximeter of claim 7, wherein said biasing means 65
`comprises a plurality of springs, at least two of said springs
`being secured to each of the ledges at a given distance away
`
`8
`from each other to provide an evenly distributed biasing
`upward support force for said non-fixed portion, so that
`when a finger is inserted between said fixed and non-fixed
`portions, said non-fixed portion is movable vertically rela(cid:173)
`tive to said fixed portion with said non-fixed portion con(cid:173)
`tinuously being forced upward against said finger to thereby
`maintain a firm grip on said finger.
`9. Pulse oximeter of claim 8, wherein said springs are
`compression coil springs.
`10. Pulse oximeter of claim 7, further comprising a circuit
`board coupled to the upper surface of said fixed portion,
`electronic components and a display being mounted to said
`circuit board, said fixed portion having an aperture through
`which a light from a light emitting device electrically
`connected to said circuit board passes for illuminating a
`15 finger placed below said fixed portion, a cover being placed
`over said circuit board and fixedly coupled to said casing.
`11. Pulse oximeter of claim 10, further comprising a
`battery module removably coupled to the underside of said
`non-fixed portion for supplying power to said electronic
`20 circuit components and said display.
`12. Pulse oximeter of claim 10, further comprising a
`switch mounted to said casing to enable a user to manually
`activate said electronic circuit components to measure the
`blood oxygen saturation of arterial blood from said finger
`25 gripped by said fixed and non-fixed portions.
`13. Pulse oximeter of claim 6, wherein said fixed portion
`and said non-fixed portions are respective elongate members
`with respective opposing surfaces positioned in alignment
`with each other, said pulse oximeter further comprising:
`respective finger pads each attached to a corresponding
`opposing surface of said elongate members, said finger
`pads are configured to follow the contour of a finger so
`as to enhance the gripping of a finger placed between
`said finger pads.
`14. Apparatus for gripping a finger, comprising:
`first grip means;
`second grip means opposing said first grip means, said
`first and second grip means having respective surfaces
`facing each other being contoured to enable the grip(cid:173)
`ping of a finger placed therebetween;
`wherein one of said first and second grip means is fixed
`while the other of said first and second grip means is
`movable vertically relative to said one fixed grip
`mea