US2341137A - Compact sphygmomanometer - Google Patents

Description

Feb. 8, 1944. v DAMRQN 2,341,137

COMPACT SPHYGMOMANOMETER Filed Feb. 6, 1943 N TOR.

Arro/e/vsv.

Patented Feb. 8, 1944 UNITED STATE-S PATENT OFFICE COMPAGTISYHYGMOMANOMETER Miit6ii H. fi em n, Camp bo'ckett, em; 7 Applet-men February 6, 1943, Serial-No: 4 :5,0'25 461351119. (01128-2455) This invention fiertain's to aruggd; nonbreaka'ble, inexpensive, cor'fibict "sphygmdmas- 'nometer orap'par'atus fordeterminirig' blo'od pressure. It is barticular'ly well-adapted "for use try the armed forces in the field, "although ififhiay also be employed to advantage whenever and wherever it is desired to ascertain diastolic *or systolic bloodpresi'sure. The device iseharacte'r- 'iz'ed by its simplicity, freedom from fluids and usefulness. Itis ai-daifited to perfriit readings'to he made rapidly and the patient may tatke his otlh blood pressure'tvithout the assistance of others.

The device compr se in effect, auriita-ry'; pres:- =sure applyinguhd indicating meaii's'; the dial of the instrument bing'cali'brtted directly in niillimeters of mercury'fdr-systolicpressure as deternzined by a stethoscopettrid 'r'nrcury rria'hdha- -e er.

' The most common type of sfphygmomanometer employs *a silk 'c'overe'd banda geflike, 'inflataf ble tube which is wmpeea around the arm andinfltte'd by means of a; hand puii'i'p, this inflatable bandage being esseeiap with a, mercury rhetn or'ne'ter. Itis imposs'ible'to takee rapid reading with this type "or iristrurnerit-"andmettixs must be provided for supporting the manometer in 'avertical positioii. Asa result; the' iris trumeht is unsu'ited for use in the [field "orfwi'th the armed forces and'is 'bul k y, 10'reatkalo'le' and ordinarily requires the use of a; stethoscopein order to take readings. I

In comparison, the device of the present'inte'ntion is extremely small and compact arids'libstahtially unitary, inasmuch as the pressure applying a'nd mdicating means are an integral part 7 er the device. v 1

Generally stated, theflevic'e comprises a small housing provided with, 'a 'wmqdw through which a, calibrated dial is Visible, "the dial being' {cajlibrited in millimeters of mercury. A yieldalzll'e pressure plate forms oh s ide'of the device. 'Ih "use, the pressure plate is applied to the imi'e'r arrii soa's ttfcdnipre'ssthe brachiai trtery' against the lower fiajrt'of *fihhurnerus', the pr'essurebeing gradua'llly increased iihtiltheplils can notbe-felt.

-'I-he systolic pressure cfifithefibe read directly through'anopefiirig' or wiridow in the case. The 'yieldable pressure of the pressure plate is suppliedhy a; s'pr'ifi so 'thatthe'dei/ice issuhsltar i tially gearless, free from fluids vat-rid praeueeu lion-breakable. I

It is ari obj-eel? of the pre se'r'it invention; there fore,- to disclose and iirdvi'de a 'sfihygniomanometer which-asinex ensive; rugged 93nd emeact; j A fur-'tfler elej e'ot o'f the ele ant in've'fitiofi is to :disclo'se andprovide an improved compact-sphygmomanometer which is adapted to pbrm1t readines to be made rapidly;

A still further 'object of the invention/is to diselo'se a'hd provide a compact rsphyg'momandmeter in which the pressure applyingvandr indlcat ihg means are substantially integral; the sphygmomanome'ter being free from fluids, gearing and other delicate, breakable 'p'i'lts. v

A-still further object 0f the invention ist0'1dis close' a-fid provide acorn-pact, and rugged :sphyg-'- rimihmidmtr ptrtiotflali'ly well adapted fbrw'tlse hyj-thfa-rrhd' forces oh the field of ba'ittle;

These and other objects; use's, aldvantages, adaptations and modific'ettions wfll b'ecoine apparent-to those skilled iii the aft Trdni tl1'e following deta'ild description er aln i'ierfiplery form inwhich the present inver'itio'n'rr'iety be embodied. In the description given hereinafter; reference Will b'lfiad to the appe'fid'd drawing; in which:

Fig. '1 shows the device in' use.

Fig; 21'5-8; fro'fit levatiorl.

Fig. 3' is a side elevaitioil. I

Fig. 4 is a side elevation of "the pressure plete 'sideof thede'vice.

Fig. 5 is an emerged transverse seetwn tatkh 'a 'lon the plane 'v' v arm.- 2.

Fig. 6 is an enlarged trensversesection through thesteir'r on'ly.

ZBy referring to thedrawirrg it will be noted that the device comprises a housirig gen'erally indiated at l,--ha-vin"g the sides 2 arid 3; An opening or window 4 is praviaed iii the housing, said Window inc'ludirig' a pdifitefer otherindex lrieiilbr 5 to faldilitat accurate r'ea diif 0f 534 calibrated dial positiohedwit-hin the hou'siii'g-es described heretfter. Thedevioe' also ifl'llldS a pressure, Dlalte 6 which; as b'stillutraltedih Fig. 4 is 'pr'ov'ided With'; c'oricave' edge '1 daffite'd to cooperate with a; ;p'ortioh of the human anatomy and thereby facilitate the afifiliatibfl and use of the device. If desired, asir'ii-iler emacave edge I nij be' formed irith-bb'pbsite margin of the firs'sufe filait *6. The :presshre plate-Q is yieiddbiy urg aeway from the musing I as "by meme of esbire-l wmpmsemnspring-t fis'itifirid between the fifes's'lir plltififrd the a hinged or even a ball and socket connection so as to permit the plate 6 to be tilted somewhat out of a plane perpendicular to the axis of the stem H]. A ball and socket type of joint is illustrated in detail in Fig. 5, the outer end of the stem It! being provided with a ferrule ll whose fingers grasp a ball-ended bolt attached to the pressure plate 6.

The stem Ill extends through a port l2 formed in the side 2 .ofthe housing I. The port lZ-may be formed directly inthe side 2- of the housing or it may be formed in a removable disc l3 threadedly connected as indicated at M, to the side 2. The stem l also extends through a port l5 formed in a partition l6 within the housing I, this partition, in cooperation with a dome l1 formed in the side 3 of the housing, forming a space within which one end of the stem in may move. The end of stem [0 is provided with a head I8 which abuts the partition l6 and limits the outward movementof the stem l0. underthelinfluence of the spring 8. I

The partition l6 mayhem the form of a thimble whose edge abuts theinner surface of the side 3, saidthimble being threadedly connected to the .dome l1. Serrationslin the edge of the thimble 16 may then cooperate with slit ridges in the inner surface of the side -3 so as to prevent rotation of the partition thimble It.

Means are provided forpreventing rotation of the stem l0. Such meansmay comprise a longitudinal or axial groove 20 formed in the outer surface of ,thestem l0. and a dog or key cooperating with such groove, the dog or key being a part of or mounted in the disc l3. 7 Rotatably, mounted withinthe housing I is a rotatable member, such as a disc or wheelZl, provided with an axial opening through which the stem Illzextends. The hub wheel 2| maybe provided with small, circular outsta-nding beads 22 adapted to act as anti-friction means between said wheel, the disc [3, and thepartition IS.

The wheel or disc 2 l, is=preferab1y. provided with indices, which may be carried by the flange 23, the indices being thus madereadily visible through the opening or window! in the housing I.

Means are provided for translating the axial .movementof the pressure plate 6 and stem in into rotary motion of the disc or wheel 2|. Such means may comprise aspiral groove 24 formed in the stem 10, and a suitable dog or key carried by the wheel 2l and-adapted to extend into the groove 24. Since the Wheel 2| is restricted from axial movement by the disc I 3, and the partition 16, axial movement of the stem. ID will be translated into rotary movement of the-wheel 2|.

A lightbellows made ofsilk, clothor any other suitable material may extend between the plate Sand the side 2 of the housing I, as indicated at 21, for the purpose of protecting the spring 8 and the-stem l0 from moisture, dust and the like. .The bellows 21 is preferably attached '.to both the plate and the side of the housing.

The spring 8 preferably has a resistance equal to about 250 millimeters of pressure, thereby making certain that the arterial flow of blood will be stopped when the ,pressure plate 6 is applied to an artery or to the skin immediately above a ,relatively exposed artery onthe body and pressureis applied to the/opposing side 3 of the housing so as to ,virtuallycollapse thespring 8.

The calibrations or indices carried by the flange ection molding.

pressure with which the pressure plate is actually pressed against a surface or artery.

The device described hereinabove may be used most successfully in the determination of systolic (and diastolic) pressure by causing one of the concave portions 1 or 1' of the pressure plate to fit above the internal condyle of the humerus, thereby causing the pressure plate to assume a position on the internal surface of the human arm above the elbow and directly over the bra chial artery. By holding the-instrument against the palmar surface of the'fingers of one hand and placing the pressure plate against the inner side of the patients arm in the manner indicated, the device may be pressed against such inner surface so as to cause the pressure plate 6 to press against the brachial artery to shut off the flow of blood through said artery. The arterial pulse in the wrist is simultaneously felt by the operator, who observes the movement of the calibrated dial or wheel through the window 4 of the device. The pressure (as indicated by the calibrated disc or wheel) at which the arterial pulse ceases will be noted and representsthe systolic blood pressure of the patient.

Preferably this reading is taken rapidly, that is, the pressure of the device against the inner arm is raised quickly so as to shut off the flow of blood through the artery, thereby preventing collateral circulation (through other arteries of the arm) from masking the readings.

' The diastolic blood pressure may also be obtained by the use of the devic and by the use the compositions (resinous, phenolic, etc.) having the desired strength and rigidity. The plate 6 should be sufficiently strong to present a smooth, flat, virtually incompressible surface during use. The instrument may be made in large part by It will be understood that the present invention is not limited to the use of any specific materials or compositions of matternor to the precise size or form of the instrumerit In actual practice,'however, it has been found that the entire device need not exceed two inches square in a cross section transverse to the axis of the stem l0.

7 Those skilled in the art will appreciate that various changes and modifications may be made without departing from the spirit of the invention here disclosed. For example,'the rotatable member or wheel- 2| need not carry the flange 23 but instead indices-may be carried along the edge, portions of the'wheel 2|, the window 4 bei'ngthen placed in the side 3 of the device so as to permit readings to be made easily. Moreover, various forms of. thrust bearings may be employed instead of theanti friction beads 22.

The precise form of device here illustrated is particularly welladapted for-use onthe brachial artery against the lower-part of the humerus.

The shape of the pressure plate may be changed, however, in th event-it is desired to use the body, permitting the patient to take his own pulse and simultaneously observe the reading, When an operator is taking another persons blood pressure with the instrument, it has been found desirable to place the patients arm across the body of the observer with the inner side of the arm away from the body of the observer, whereupon the observer may take the pulse with the fingers of one hand and press the device against the brachial artery with the other hand, the patients arm being thus held between the device and the body of the observer. These are suggestive and illustrative modes of use, other methods readily occurring to the operator with changing circumstances.

All modifications and adaptations coming within the scope of the appended claims are embraced thereby.

I claim:

1. A compact and rugged sphygmomanometer comprising: a housing; a port into one side of the housing; a stem axially movable through said port, said stem being provided with a spiral groove on its surface; a rotatable member in the housing, said member being provided with an axial bore and a dog adapted to engage the spiral groove on the stem; means for restraining said stem from rotation with respect to the housing; a pressure plate carried by the outer end of said stem; a universal connection between said pressure plate and stem; spring means between the housing and said plate yieldably urging said plate and stem away from the housing; a window in said housing adjacent the edge portion of the rotatable member; and indices carried by the edge portion of the rotatable member and visible through said Window, said indices denoting pressure in terms of millimeters of mercury.

2. A sphygmomanometer of the character described in claim 3 characterized in that the edge of the pressure plate is provided with a concavity adapted to cooperate with the internal condyle in facilitating the placement of the device with respect to the brachial artery.

3. A compact and rugged sphygmomanometer comprising: a housing; a port in one side of the housing; a stem axially movable through said port; means for restraining said stem from rotation; a pressure plate carried by the outer end of said stem, said plate being adapted to be placed over an artery; spring means between the housing and said plate yieldably urging said plate and stem away from the housing; a rotatable member in the housing; means for translating axial movement of the stem into rotation of the rotatable member, said means comprising a spiral groove formed on the surface of the stem, and a dog carried by the rotatable member, said dog being adapted to engage the spiral groove on said stem; a window in said housing adjacent the edge portion of the rotatable member; and indices carried by the edge portion of the rotatable member and visible through said window.

4. A compact and rugged sphygmomanometer comprising: a housing; a port in one side of the housing; a stem axially movable through said port; means for restraining said stem from rotation; a pressure plate carried by the outer end of said stem, said plate being provided with a virtually fiat face adapted to be placed over an. artery; spring means between the housing and said plate yieldably urging said plate and stem away from the housing; a member mounted in the housing for rotation in a plane perpendicular to the axis of the stem; means for translating

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