US2098272A - Therapeutic apparatus - Google Patents

Description

NOV. 9, 1937. s. BENSON 2,098,272

THERAPEUTIC APPARATUS Filed Maf0h 25, 1935 4 Sheets-Sheet l "f, 23a @j A Elin-i@ Aflac/ador' Samia efas'aza Nov. 9, 1937. s, BENSQN 2,098,272

THERAPEUTI C APPARATUS Nov. 9, 1937. s. BENSON 2,098,272

THERAPEUTI C APPARATUS Filed March 25, 1935 4 SvheetS-She'et 3 ggg-fg NOV. 9, 1937. n s BENSQN 2,098,272

THERAPEUTIC APPARATUS Filed MaICh 25, 1935 4 Sheets-Sheet 4 1022 zal? 93? SQP g5 .911? 62'? 5P M510@ 99 2002 ji' y L defaofx amm ezasaza Patented Nov. 9, 1937 UNITED STATES aosaz'za THERAPEUTIC APPARATUS Simon Benson, Chicago, Ill. Application March 25, v1935, Serial No. 12,863

l19 claims.

My invention relates to therapeutic apparatus. More particularly it relates to apparatus for subjecting a member or area of a patients body to abatmospheric (that is, either above or below atmospheric) treatment and to an apparatus and method for effecting an air-tight seal between the member or area undergoing treatment, and the chamber or receptacle whereby the treatment is administered. This abatmospheric treatment or uid pressure treatment (the iluid usually being air) may be by either negative pressure or positive pressure, or it may be by both alternately.

The most usual purpose of this type of abatmospheric pressure treatment is for obliterative vascular diseases and its contemplated function is to stimulate circulation through existing vascular systems including the peripheral systems and also to establish detour vascular systems about the obliterations.

The chief object of my invention is the provision o f a seal which is non-constrictive of the vascular circulation. Seals now commonly in use are of a type which tend to press against the tissues of the member or area and thereby constrict circulation, and especially the outer or venous circulation, thereby defeating the very purpose of the treatment. This constriction has made it necessary to interrupt negative pressure treatment at intervals by allowing the treatment chamber pressure to come up to atmospheric pressure or to build up to a positive pressure so venous blood, retarded by the constriction of the seal, may be cleared and the patient be given some momentary relief from the often acute pain resulting from the stifling of the venous circulation by the constriction of the seal and this periodic interruption of the suction to build up atmospheric or positive pressure in the treatment chamber has been necessary even in those instances where, from the standpoint of the treatment itself, it would be preferable to maintain an uninterrupted suction for a long period of time.

In general, I realize my object by bringing the skin of the member or area away from the body and against the sealing ring in sealing contact therewith, as distinguished from bringing the sealing ring down against the skin and into pressure against the subcutaneous tissues. Preferably I accomplish this by pneumatically sucking the skin outwardly against a sealing ring and into sealing contact therewith. My seal is such that it may be used, even without alteration or adjustment, for either'negative or positive pressure in the treatment chamber or for treatment where the chamber is subjected to negative and positive pressure alternately or where the pressure alternates between negative or positive and atmospheric pressure. l

Another and auxiliary object of my invention is the provision of such a non-constrictive seal 5 in the two somewhat different instances of a limb, Where an encircling sealing ring may be used, and a more or less at body area where the seal will not come along a radial face of the sealing ring, but at the lateral face thereof. The l0 gist of the distinctions between these two instances is that with a limb, where an encircling seal may be used, the suction in the treatment chamber is more or less balanced radiallyv of the limb; whereas in the instance of the flatwise apl5.

plication of the sealing ring, suction within the treatment chamber tends t0 pull the chamber itself against the body, thereby creating an inward pressure which still further aggravates the objectionable vascular constriction. 20

Another object of my invention is concerned with pressure control means whereby the treatment chamber is subjected t'o negative and positive pressure alternately.

The foregoing, together with further objects, 25 features and advantages of my invention are set forth in the following description of specific embodiments thereof and illustrated in the accompanying drawings, wherein: f

Fig. 1 is a diagrammatic view in elevation of 30 apparatus for subjecting an arm to uid pressure in a chamber;

Fig. 2 is a plan view of the chamber and sealing cuff;

Fig. 3 is a vertical sectional view of the cufl` 35 and cover of the chamber, taken along the line 3-3 of Fig. 2;

Fig. 4 is a detail view of the cuff, taken along the line 4 4 of Fig. 2;

Fig. 5'is a longitudinal vertical section of a 40 treatment chamber of the type adapted to receive a leg, and incorporating another and preferred form of seal;

Fig. 6 is an enlarged vertical section through the sealing ring of Fig. 5; 45

Fig. 7 shows in radial section a modified form of sealing ring;

Fig. 8 shows in radial section still another form of sealing ring;

Fig. 9 is a transverse detail section of the seal 50 of the form of Fig. 8, taken on the line 9-9 of Fig. 8;

Fig. l0 shows still another modified form of seal in radialseCtion;

Fig. 11 shows in vertical section a treatment 55 chamber and sealing ring of the type adapted for application more or less atwise to a body area;

Fig. 12 is a side elevation of the pressure generating and controlling apparatus, showing in connection therewith the chamber of Fig. 5;

Fig. 13 is ay vertical transverse section of the pulley wheels, taken on'the line |3|3 of Fig. `12;

Fig. 14 is a radial section, taken on the line |4|4 of Fig. 12 through the Vrim of the cam wheel, showing atypical cam block;

Fig. 15 is a perspective View of a typical cam block for thecam Wheel; l

Fig. 16 is a development of the built-up cammed periphery of the cam wheel, and 4 Fig. 17 is a horizontal section of the regulating valves, taken on the line |`|-|'l of Fig. 12.

This application constitutes a continuation in part of my application Serial No. 515,350, led February 12, 1931, on Apparatus for sealing.

In the form ofFigs. 1 to 4, inclusive, I have shown a vertically disposed cylindrical chamber 2| large enough'to contain comfortably a mans arm. An air-tight cover 22 is secured to the top.r

of the chamber in any readily removable fashion. The cover-has an inlet 23 and an outlet 23a, each provided with a stopcock. The cover has a central opening conforming to the shape of the portion of the body member to be sealed. A sealing ring or cui 24 is 'fitted into this opening and securely attached to the cover. The cuff may be made of metal,` glass, hard rubber, or composition materials. IAs shown in Fig. 4, the vertical surface ofthe culi is slightly concave and the horizontal section follows the cross-section of the body memberto be sealed.

It is essential 'that the portion of the member upon which the seal is to be made when the member is in thechamber be in close proximity to the inside wall ej the cuff, but it must not t so snuglyfthat lthe circulation of the blood is in any manner .constrained or impaired. Since the size and shape of mens, womens and childrens limbs vary greatly, andsince on some occasions it will be desirable' to seal` the entire leg or arm of vthe'patient, rand on others just a portion of the memberfit is necessary for doctors and others giving treatments, as hereinafter described,l to have available a supply of cuffs of diierent sizes and shapes. However, cuis fashioned from hard rubberor a composition material and provided with slots to receive sections to enlarge the cuff .have eliminated somewhat the necessity of mainor sealing ring, with an annular recess or cham- A'ber 25 between the casings or walls.

AThe outer casing 26 is rigid and restsupon and is secured to the top of the cover. The elliptical inner wall or casing is comprised of three parts, as bestshown inFilg. 4, the top section 2'! being a coninwardly of the upper and lower sections, comtinuation ofthe outer casing 26 bent over in the nature of a bead, thus forming a closure for the recess 25 between the walls. The lower section 28 of the inner wall is tted into the opening of the cover and is `secured to the inner side of the cover and extends somewhat above it. A section of foraminous material ZS-preferably ne mesh wire screening-extends between and .sealed body member. The various parts may be of metal secured together in a leak-proof manner, for example by soldering.

As shown diagrammatically in Fig. 1, the tubing 30 connects the air recess 25 of the cui with a vacuum pump 3| and a manometer 32. The

vacuum pump 3| is employed to reduce the pressure inthe air recess 25. The chamber 2| is here shown as containing water as the fluid medium. A seal is effected between the chamber and the arm by sucking the skin of the arm adjacent the cuff 24 against the concave inner wall of the cui.' This sucking is accomplished by reducing the pressure in the air recess 25 by operating the vacuum pump 3|. 'I'he skin adjacent the entire inner wall is thus drawn tightly against said wall and forms an effective seal. In case the skin should be drawn away from the cui in any manner, the break in the seal would be immediately' reected in the manometer 32. The advantage of my apparatus lies in the fact that an air-tight seal is secured without in any I shall next describe the apparatus for subjecting the chamber 2| to negative or positive pressure. Tubing 34 connects a graduate 33 with the chamber past a stop cock 35. Another manometer 36 and another pump 31 gcapable of producing both negative and positive pressure) are separately connected to the graduate 33. In operation, the patients forearm-or, in apparatus of' different size and shape, the patients leg-is placed within the chamber 2| and the cuff 24. The arm and cuff are then sealed in the manner described and the chamber and 'tubing to the inlet to the graduate illled with water (if a liquid medium is to be employed) through the inlet 23. the stop cock 35 being open while the chamber and tubing are being iilled.

When the apparatus is used for therapeutic treatment, the pump 31 is operated to intermittently reduce and increase the pressure within the chamber. 'Ihis may be done, for example, by reversing the motor of the pump, or by connecting the conduit to the chamber alternately to the negative and pressure sides of the pump, de-

pending of course upon the type of pump employed.

In Figs. 5 and 6, I have shown another and preferred form of sealing apparatus in conjunction with another form of chamber, this chamber being shown as adapted for the reception of a leg. Here the chamber 4|, which is glass-walled for ready observation of the leg, is of generally cylindrical shape except that it has an upper enlargement 4|' for the accommodation of the toes and ttings. A pressure inlet fitting 42, which preferably includes a pressure gage, is inserted into the chamber at the top of the enlargement 4| by means of a rubber stopper, for example, and is connected with the chamber end of a treatment pressure hose 43 leading from a regulated source of pressure, which as hereinafter explained may be either negative pressure or positive pressure, or both alternately. The vchamber is preferably provided also with a thermometer 44 and an electric heating unit 45, it being desirable in many instances to conduct a treatment under controlled elevated temperatures.

The open end of the glass chamber 4| through which the leg is inserted, is provided with a sealing cuff 46 of rubber or other exible but not limp material. The cuff may be of frusta-conical shape with its enlarged end embracing the beaded end ofthe chamber 4| vand secured thereto by a clamping ring 41. The smaller or outer end of the cuff 46 forms a sealing ring 48. To prevent collapsing of the cuff under internal suction, while permitting considerable flexibility, I prefer to incorporate longitudinal stays 49 at radially spaced intervals, which stays may be molded into the rubber of the cuff. The sealing ring 48 may be of rubber molded integrally with the body of the cui. The rubber of the ring, 48 is preferably of about the exibility of the tread of an automobile tire or slightly more resilient andexible. To be precise, the ring should be resilientenough easily to adapt itself to varying oval shapes, out of its normal round, so that it will adapt itself to the contour of a patients legs, and still not be so limp that it will buckle and thereby ensmall its circumference, lfor the latter would result in a constriction of the limb.

The ring 48 has an inner skin-engaging face 50 which opens into a sealing recess or chamber '5| by a slot 52 through the sealing face, leaving annular corners 53. A nipple 54 molded into the outer wall of the sealing ring 48 receives the end of a sealing suction hose 55 from a suction source which will later be described. The cui 46 is chosen from an available assortment of sizes so that the inside diameter of the sealing ring 48 is approximately that of the region of the leg to be treated at some convenient point above the knee. Advantage can be taken of the normal taper of the thigh to avoid the necessity of exact size for the sealing ring, the leg being pushed in until the tapering thigh substantially fits the sealing ring which, as previously mentioned, is easily deformed to accommodate itself to the oval cross-section of the thigh. When the recess 5l is subjected to the sealing suction through the hose 55, the skin is drawn into the recess, making sealing contact all around the thigh at two longitudinally spaced circles dened by the salient corners 53 over which the skin is thus drawn. But to avoid drawing the skin so far into the recess 5i that the skin will become unduly stretched over the corners 53 and become painful, I provide a skin-supporting foraminous wall 55 of woven wire or perforated sheet stock, molded into the rubber of the sealing ring 48, as shown in Fig. 6. This limits the in-drawing of the skin, but littl-e step-down being required to render the salient corners 53 effective for sealing contact.

As far as the sealing itself is concerned, this may be accomplished by the modification shown in Fig. 7, where the sealing ring 48a has a narrow slot 52a. in its skin-engaging face 58a leading to the suction recess Ella, but no supporting wall is used across the recess. The skin will be sucked into effective seal with the closely spaced salient corners 53a., but, as compared with the form of Fig. 6, this has two objections. One is that the skin will be drawn out into the slot to form a narrow but high ridge, which will prove painful to the patient and leave an objectionable ring for some time. The other objection is that the total area of the skin subjected tothe sealing suction is much less and, therefore, the skin can be torn away from sealing contact with the sealing ring by lesser force than is required in Fig. 6, for example, where the area of skin subjected to suction is considerably greater.

In Figs. 8 and 9, I have shown a further modication of sealing ring 4817 where the skin-engaging faces 50i)I may be formed by a pair of metal rings each of L-shaped radial section, although the same principle may be worked out all in molded rubber. Here the slot 52h dening the salient corners 53h does not open directly into the sealing recess 5Ib, nor is there a perforated skin-supporting wall. Instead, the skin-supporting Wall 56h is imperforate, but spaced from the back side of the skin-engaging face 50h by fluted edges 54h. Thus, the sealing suction to which the recess 5Ib is subjected finds its way to the skin around the lateral edges of the Wall 56h and sidewise into the slot 52h.

In Fig. 10 I have shown a still further modification of the sealing ring. Here the sealing ring 48e is built up from thin and rather flexible sheet metal and the skin-engaging face 50c is flush with a central perforated area 54e Without employing outstanding annular corners such as 53. This form of seal is not so satisfactory in operation because, lacking the annular sealing ridge 53, a pull on the skin away from the sealing face 50c can easily overcome the small force of the suction on the area of one or two of the holes of the perforated area, freeing them independently of the others. Then, another two or three can be` released independently of the others, and so on, until the entire seal is broken by increments. Also, as the skin is drawn away from more and more holes, the atmospheric leakage into the sealing recess 5Ic reduces the suction therein and further contributes to the ready collapse of the entire seal.

When the treatment chamber 4l is subjected to negative pressure, it will tend to suck the leg in farther into the treatment chamber by a force representing the pressure times the area encompassed by the sealing ring 4B. Pulling the leg farther into the treatment chamber would have the objections of longitudinally stretching the skin of the contained leg (inasmuch as the seal 48 will not permit the slipping of the skin) and of the tapered thigh when moved farther in, bringing a region of the thigh of larger diameter into the sealing ring to the extent allowed by the sliding of the skin upon the subcutaneous tissues, thereby constricting circulation. To prevent such inward movement of the leg I provide a footrest R within the treatment chamber which footrest may be adjusted by external manipulation of a screw which is threaded through a bushing in the end wall of a chamber, as showin in Fig. 5. Or, the treatment chamber and the body may each be secured to the bed or treatment table. I

When the treatment chamber is subjected to positive pressure, there is a corresponding tendency to push the leg out. This may be remedied by the latter suggested arrangement or by suitably harnessing the treatment chamber to a waist belt or shoulder yoke.

In Fig. 11 I have shown a modified arrangement of seal adapted to a treatment chamber which is applied more or less flatwise against a body area in those instances where the part to be treated is not in the nature of a limb which can be encircled by the sealing ring. In other words, Fig. 11 shows an arrangement where the sealing ring faces the body sidewise with its lateral face against the body, as distinguished from the forms previously described, where the seal may be of Fig. 11 is shown in an exemplary application to a breast. It is provided with a pressure inlet yfitting 42d, and associated pressure gage, connected with the treatment pressure hose 43. It

also has a thermometer 44d and electric heating element 45d. The sealing ring 48d is connected with the open end of the cup by a flexible collar which, by analogy, I shall call a cuff 46d which is held against the chamber by a clamping ring 41d. The skin-engaging surface 50d of the sealing ring 48d is on the lateral side rather than facing radially inwardly, but, as in the form of Fig. 6, it includes a central slot 52d defining concentric circular salient corners 53d and leading through a perforated skin-supporting Wall 54d to the annular suction recess 5|d.

Whereas in the encircling form of sealing ring the vring is preferably yieldable out of its round configuration, to accommodate itself to the contour of the limb, in the tangential application of Fig. 11 the sealing ring must be yieldable out of a piane, because there are few places on the body where a planar sealing ring would effect a close enough t with the body area to provide a satisfactory seal. The flexibility of the rubber of which the sealing ring 48d is formed, permits it to be moved out of a plane to accommodate itself to the contour of the body. For holding the skinengaging face 50d of the sealing ring in this nonplanar body-conforming position I provide a plurality of, say, six arcuately spaced sockets 51 molded into the ring 48d. Each of the sockets 51 embraces the balled end of a threaded positioning rod 58. The rods 58 pass through ears 60 outstanding at corresponding arcuate intervals from the clamping ring 41d. By thumb nuts 59engaging the upper and lower faces of each ear 60, each rod 58 may be positioned vertically to hold the sealing ring at that region at the desired height relative to the treatment chamber, to effect the conformation of the sealing ring to the body. The holes in the ears 60' through which the rods 58 pass, are preferablyradially elongated because the radius of the rod from the vertical center line of the treatment chamber will vary at diierent elevations of the sealing ring.

In Fig. 11, it will be understood that the patient is lying on the back upon a treatment bed or table. For supporting the treatment chamber I provide a standard 62 which may rest upon the floor and carries a vertically adjustable U-shaped bracket GI, the arms of which are connected to diametrically opposite sides of the clamping ring 41d, as by trunnions.

The supporting standard not only relieves the patient of the weight of the treatment chamber, but, also, through the sealing ring positioning rods 58, definitely holds the sealing ring at a fixed elevation so that the skin is sucked up against the sealing ring rather than the sealing ring being sucked down against the skin and thereby constricting the circulation into the region being treated. The sealing ring so firmly engages the skin bounding the area being treated that, even though the treatment chamber be subjected to considerable negative pressure, the tendency of thattreatment suction to pull the exposed area into the chamber is successfully resisted. The sealing ring 48d, while flexible, is sufficiently rigid to withstand such buckling as would ensmall its perimeter, and thus the sealing ring itself can not be drawn radially inwardly or upwardly by negative pressure in the treatment chamber.

I shall next explain the apparatus for supplying controlled pressure to the treatment chamber and the sealing rings of the forms shown in Figs. 5 to 11, inclusive.

The specic type of treatment suction control apparatus which I have here shown somewhat schematically in Figs. 12 to 17, inclusive, has been selected because it affords a wide range of flexibility. The treatment suction may be kept at a constant negative pressure or at a constant positive pressure, or it may be periodically varied between predetermined degrees of pressure, either al1 negative pressure or all postiive pressure or alternating between positive and negative pressures, and the transitions between various degrees of pressure may be accomplished either abruptly or very gradually, and the time period of the cycle may be varied as well as the proportion of time allotted to each predetermined degree of pressure. In short, the pressure control is arranged to provide the desired degree of pressure in the treatment chamber for each moment throughout a predetermined cycle.

Such pressure control apparatus as here illustrated comprises (Fig. 12) an electric motor 65, a suction or negative pressure pump 66N, and a positive pressure pump BGP conveniently arranged upon a common base 68. Through a manually shiftable clutch 69 the motor drives a worm 10 which engages a Worm wheel 1| on a transverse shaft 12. The worm wheel shaft 12 carries a lower stepped pulley 13 (Fig. 13) which drives an upper stepped pulley 14 on an upper pulley shaft 15, also journaled in a pulley frame 16, through a belt 11. The upper pulley shaft 15 also carries a cam wheel 18 which operates the pressure control valves as the cam Wheel revolves. The cam wheel 18 has a peripheral rim 18 (Fig.I 14) in the outer face of which is a centrally arranged annular slot for the reception of the securing flanges of the various cam blocks B (Fig. 15). A

A,yokeiike bracket 8l, which may be a fixed extension of the pulley frame 16, supports on one side of the cam wheel (Fig. 17) a positive pressure control valve indicated generally .as 82P and on the other side a negative pressure control indicated generally as valve 82N.

I shall rst describe in detail the positive pressure control valve 82P for the treatment chamber. A positive pressure control arm BSP is pivoted at one end at 84P on the xed bracket 8|, while thel other end carries a roller 85P which engages the adiacent lateral cam faces of successive cam blocks B arranged about the periphery of the cam wheel rim 19. Through an adjustable cap screw BBP the arm BSP engages the inner spring cup 81P which embraces one end of a spiral regulating spring 88P, the other end of which is embraced by an outer spring cup 89P. The spring may be encased by a telescoping cylindrical shell SOP.

The outer spring cup 891? is mounted on the end of a protruding valve stem SIP which is slidably mounted in and extends through the valve body 92P. The valve stem carries a pair of `spaced valve heads 93P cooperating with valve seats 94P to provide a substantially balanced valve. The valve controls the flow of air from the pump side passage 95P (which is connected by a pipe BBP to the discharge side of the positive pressure pump SSP) to the chamber side passage 91P of the valve body (which is connected through a pipe 98P to a T fitting 99 which, in turn, is connected to the hose 43 leading to the treatment chamber).

The valve stem SIP is normally urged to its Aclosed position by a light biasing spring |001?. A

diaphragm IMP is fixed across the open side oi.' a cupped diaphragm housing |02P defining a diaphragm chamber |03? subject to the pressure of the treatment chamber by a small tube |04P leading from the chamber |03P to the chamber side passage STP.

. The operation of the positive pressure control valve 82P, whose structure has just been described, is as follows: If the cam blocks B on the cam wheel have been so arranged as to call for positive pressure in the treatment chamber at spine point in the revolution of the cam wheel (that is, at some period during the cycle of operation), the cam faceof a suitably conformed cam block B will engage the roller 85P, camming it upwardly (Fig. 17) to swing it about the pivot 84P and thereby press the spring cup 8`|P upwardly. The diaphragm chamber |03P being at or under atmospheric pressure, no resistance is .offered to the upward movement of the valve stem SIP, save the easily overcome biasing spring |P. Accordingly, the valve heads 93P open, permitting air under positive pressure to pass from the pump side passage 95P (which is supplied in excess of maximum requirements by the positive pressure pump 66P) to the chamber side passage 91P and thence through the hose 43 to the treatment chamber. As pressure builds up in the treatment chamber it will correspondingly build up pressure inthe diaphragm chamber |03? until the downward pressure on the diaphragm overbalances the pressure of the regulating spring 88P, corresponding to the compression as xed by the positionof the arm 83P, and upon the occurrence of such overbalancing the valve will be fully closed. Whenever the positive pressure in the suction chamber falls below that determined by the position of the arm 83P, the spring 88P will overbalance the reduced pressure in the diaphragm chamber |03P and reopen the-va1ve until the pressure has again reached the predetermined degree.

When the cam blocks B call for a reduction in positive pressure, after a positive pressure has been built up, the arm 83P will swing downwardly leaving thevalve closed. Ordinarily this would leave trapped in the treatment chamber 4| the maximum positive pressure which was built up and the treatment chamber positive pressure would not bereduced, as called for by the cams. To avoid such a situation I provide a relief vent valve |05 in the form of an adjustable needle valve which permits a small but constant bleeding of the chamber pressure line through the vent |06. This gives a fairly prompt relief for any positive pressure trapped in the treatment chamber after the cam wheel has required a lesser positive pressure. The relief needle valve |05 is set for such an adjustment that pressure will -be-relieved in the treatment chamber at the maximum rate at which it will be desired to have the pressure drop. On the other hand, the relief port will not be so great as to throw an unnecessary burden on the positive pressure pump or substantially impede the rapid building up of desired positive pressures within the treatment chamber.

When the treatment chamber is subject to negative pressure, the corresponding negative pressure will also obtain in the diaphragm chamber |03P, tending to liftthe diaphragm I0|P.

It is therefore important that the upper end of the valve stem SIP merely abut the diaphragm |0|P instead of being secured thereto, for otherwise,subjecting the treatment chamber t0 suction` pressure. would open the valve 82P and destroy the negative pressure.

I might explain, to avoid any confusion. that in referring to Fig. 17, where I have used the terms up and down in connection with the operation of the valve parts, I am using the terms only in reference to the sheet; the figure is a horizontal plan section and the parts work in the horizontal plane. l

The negative pressure control valve 82N, as will be seen from Fig. 17, is substantially similar in construction and operation to the positive pressure control valve 82P just described, save that the'roller 85N contacts the opposite face of the several cam blocks B and the diaphragm chamber |03N is in reverse arrangement so that when it is subject to negative pressure the diaphragm |0|N tends to close the valve.

The pump side passage 95N communicates with the pipe 96N leading to the intake of the negativepressure pump 66N.

The operation of the negative control valve is as follows: When the cam blocks B on the cam wheel engage the roller 85N to swing the control arm 83N downwardly tending to compress the spring 88N to open the valve, the diaphragm |0|N yields, permitting the valve to open. Air is thus drawn from the treatment chamber through the hose 43 and pipe 98N past the valve and through the pipe 96N to the suction pump 66N. When the negative pressure built up in the treatment chamber, and communicated to the diaphragm chamber |03N, is sufficient to overbalance the pressure of the spring 88N as compressed by the position of the arm 83N, the valve will close. The constant relief afforded by the valve |05 insures that when the cam wheel. calls for a decreased amount of negative suction in the chamber, the high negative suction will not be permanently trapped in the treatment chamber.

YBefore describing in detaii the arrangement of the cam' blocks B on the cam wheel, I shall explain the regulation of the sealing suction admitted to the sealing ring. The sealing suction regulating valve, indicated generally at 82S, is here shown as of substantially the same construction as the negative pressure regulating valve 82N except that the regulating spring 08S is subjected to a predetermined pressure or set-I ting by a suitably indexed hand screw 83S rather than by a cam-operated arm or'lever. The pump vside passage 95S of the valve communicates with the negative pressure line 96N from the pump 66N while the sealing side passage 91S is connected to the sealing suction hose 55 leading to the sealing ring 48.

In the operation of the sealing ring it is'often vdesirable to employ a relatively high sealing suction initially to pull the skin into sealing contact with the ring and then drop the sealing suction to a lower suction merely suilicient tomaintain the seal once it has' been established. These predetermined sealing suctions may be secured by the manual adjusting screw 83S and aided by 'suitable indicia which may be placed on the hand treatment chamber. And similarly,.this relief valve insures that the sealing suction is reduced to atmospheric pressure when the valve 82S is adjusted to cut oi the sealing suction.

Referring again to the cam blocks B disposed in series about the periphery of the cam wheel 18, a typical cam block B is shown in Figs. 14 and 15. The top and bottom surfaces are arcuately conformed about a radius from the axis of the cam wheel 'I8 so that when the blocks are set on the cam wheel their undersides mate the peripheral face of the rim "I9 of the cam wheel. Each block B carries a depending flange III), which extends the length of the block at one lateral edge thereof. The ange I I0 nts into the annular slot 80 on the peripheral face of the cam wheel 'I8 and is secured to the cam Wheel by a locking pin III which extends through a hole II2 in the rim 'I9 and through a registering hole I I3 in the flange I I0. The locking pin III may have a protruding knurled head and av threaded portionl lwhich is screwed into the tapped end of the hole II2 for securing the locking pin. One face, II4, of each cam block B constitutes a cam face for engagement with one of the rollers 85P-85N. Each cam block, it will be seen, is reversible whereby it may be set into the slot 8U so that its cam face II4 will be presented to whichever of the rollers BSP- 85N `is required by the cycle to be established. The

transverse Idistance between thecam face II4 and the securing ange IIU determines the lateral displacement of the roller by the cam block. The face I I4 may be parallel with the ange H0, in which case the vregulating valve will be held at a constant pressure during the arcuate travel of the block along the roller, or the face II4 may be at an inclination to the flange H0, in which case, when the given .cam block passes the roller, the roller ywill be swung transversely outwardly or inwardly as the case may be.

For convenience in building up a series of cam blocks B to give the desired cammed contour to the cam Wheel, the cam blocks, as to their arcuate lengths, are built up in multiples of 10 degrees. The peripheral face of the rim 19 may carry such radial indicia H5 as is shown in the development of the periphery of the cam wheel `which constitutes` Fig. 16. When the blocks are worked out on the basis of lO-degree multiples, locking pin holes H2 occur every 10 degrees, thus making a totalof 36 holes H2 about the lateral face of the cam wheel rim 19. It is only necessary,h'oWever, that a single locking pin be used for each cam block B although it is a convenience that the ang'e IIU of each cam block B be provided with a hole I I2 for each 10 degrees of arcuate lengthof the cam block.

I contemplate that in a hospital or clinical installation ofthe treatment apparatus using the control here shown, a large variety of cam blocks B will be available. The several cam blocks Will vary in arcuate length in the lateral displacement of the cam faceI I4 from the securing flange Illl and in the inclination of the face II4 to the flange IIU. Certain multiples for the transverse width of the cam block may be adhered to and indicated by indexed lines I I6 engraved on the peripheral face of the rim 29, as shown in Fig. 16. With the indicia II5 reading in terms of degrees and the transverse indicia II 6 reading in terms of pressure, the peripheral face of the cam wheel rim 'I9 forms, in effect, the coordinated background or field for a pressure line which, instead of being drawn'as a pencil line, is actually physif cally built up by the faces I I4 of the cam blocks B.

lIn Fig. 16, going upwardly from the ,slot represents positive pressure, while going downwardly from the slot 80 represents negative pres,-

sure. where the cam prole has been built up to show the flexibility of the control rather than to show any therapeutically preferable cycle-the rst cam block BI has a cam face which is inclined from initial zero position to a negative pressure position. Thenext cam B2 continues the inclination up to a predetermined level, which is sustained by the following three cam blocks B3, B4 and B5. As the cam Wheel is revolved in the direction represented by the arrow in Fig. 16, the positive pressure roller P will ride against the back face of the cam blocks, retaining the positive pressure control valve 82P in its zero or closed position. The inclined cam faces of the blocks BI and B2, however, will gradually dis-1 place the roller 85N, causing corresponding nega.-

tive pressure to be built up and maintained in the treatment chamber. After theV negative pressure in the treatment chamber has been maintained at a constant amount during the passage of the cam blocks B3, B4 and B5, the roller 85N next encounters another outwardly inclined cam block B6 which increases the negative suction in the treatment chamber and this higher negative pressure is maintained by the ensuing 'blocks Bl and B8. In the instance of the latter two blocks, it will be seen that when a constant negative pressure is to be maintained for 50 degrees of revolution of the cam wheel, this may be effected by using one 20degree cam block and one {l0-degree cam block, both, of course, of width corresponding to the desired pressure to be maintained.

Still following the example of Fig. .16, the roller 85N would next be passed by the cam block B9 which is inclined slightly to reduce the degree of negative suction in the treatment chamber. It is at this point that the bleeder or relief valve I05 functions to avoidtrapping in the treatment chamber the high suction built up by the cams B6, B1, B8. Following the inclined cam B9, the slightly reduced negative pressure is maintained for another 40 degrees by the cam blocks BIO and BI I. Then the inclined cam block BIZ reduces the negative pressure to zero. It will be In the exemplary instance of Fig. 16-

observed that by the great inclination of the cam .BSP and 85N to stand in zero pressure position.

The next cam BI4 is arranged so that its inclined cam face is on the opposite side of the ange I I0. The cam block BI4 thus engages the .positive 'pressure regulating .roller 85P and gradually laterally displaces it to provide a constantly increasing positive pressure in the treatment chamber. This positive pressure is built up through y20 degrees and then maintained through 30 degrees by the cam block BIS and then returned through 20 degrees to zero pressure by the cam block BI 6. 'I'here is a short IO-degree dwell at zero pressure or' atmospheric pressure by the cam block BIT. This completes the cycle which will be immediately repeated by the continued rotation of the cam wheel. It will be observed that it is physically impossible, with cam blocks ofv this design, to provide an anomalous situation supplying both negative and positive pressure simultaneously toA the treatment chamber.

In this manner each revolution of the cam Wheel 18 provides a cycle of operation for the treatment chamber, as regards the pressure therein. But the time period of that cycle is determined by the combination of pulleys employed in the stepped pulleys 13 and 14, which can be so proportioned as to give any desired speed to the cam wheel. In instances Where, for example, a predetermined suction pressure is to be maintainedin the treatment chamber for a relatively long period of time, the cam wheel may be rotated to a position corresponding to the desired negative pressure to be maintained,` and the clutch 69 may then be disengaged, leaving the cam wheel stationary and maintaining the desired negative suction in the treatment chamber until the clutch is again engaged.

It will be understood that the suction and pressure pumps 66N and 66P are of a blower type which inherently provide for their own relief when they have built up their maximum suction or pressure. Where other-types of pumps are employed it may be necessary to use, as a source of suction and pressure for the regulating valves, a pressure reservoir tank and a suction reservoir tank suitably maintained by pressure controlled pumps.

While I have shown and described these specic embodiments of my invention, I contemplate that many changes lmay be made therein without departing from the scope or spirit of my invention.

I claim:

1. A device of the character set forth compris ing a chamber, a cover for said chamber provided with an opening the size and shape of a human arm, a concave annular wall tting into said opening, a section of foraminous material forming a part of said concave wall, an outer annular wall surrounding said inner wall forming a recess intermediate the walls, and means for reducing the pressure within said recess.

2. The combination of a fluid pressure receptacle having an opening by means of which a part of a living body is exposed to the interior of the receptacle, the mounting and arrangement of the receptacle relative to the body partfbeing such that the receptacle is withheld from circulation-restricting movement against the body part by the pressure within the receptacle, a relatively rigid recessed member framing said opening', the recessed member having a pneumatically permeable side ccrnmunicating with therecess constructed and arranged for placement proximately facing the skin bounding the area of the body part exposed to the interior of the receptacle, and means for partially evacuating'the recess to suck the skin into fluid-tight sealing contact with the permeable side and away from the adjacent portion of the body part, whereby the recessed member is non-constrictive of vascular circulation.

3. The combination of a suction receptacle having an opening by means of Which a part of a living body is exposed to the interior of the receptacle, the mounting and arrangement of the receptacle relative to the body part being such that the receptacle is withheld from circulation-restricting movement against the body part, means for subjecting the interior of the receptacletovaryingabatmosphericfluidpressures,

a recessed member, of greaterrigidity than the tissue of the body member, framing the opening and having a pneumatically permeable side communicating with the recess constructed and arranged for placement proximately facing the skin bounding the body part area exposed to the interior of the receptacle, and means for partially evacuating the recess to such the skin into fluidl tight sealing contact with the permeable side and away from the adjacent portion of the body part whereby the recessed member is non-constrictive of vascular circulation within the body part, the degree of suction in the recess being different from the degree of pressure in the receptacle.

4. A means for effecting a gas-tight seal between the wall of an opening into a receptacle and the skin of a portion of a living body tissue exposed by means of the opening to the interior of the receptacle, said means comprising a relatively rigid recessed member framing said opening, said member having aside which may be brought into close proximity to the skin bounding the area exposed to the interior of the receptacle, the side comprising a. pair of spaced apart annular salient surfaces for effecting primary seals with the skin and a perforated skin-supporting member extending across the space between and oilset from the salient surfaces, and means for partially evacuating the recess in said member to cause the proximate tissue to be sucked against the open side thereof and away from the body tissue, whereby the recessed member is non-constrictive of vascular circulation within the body tissue.

5. The combination with va receptacle having an opening through which an extremity of a living' body extends into the interior of the receptacle for subjection to the pressure within the receptacle, and means for subjecting the interior of the receptacle toabatmospheric pressure-of means for effecting a duid-tight seal between the receptacle and the body extremity said means comprising an annular sealing member, of greater rigidity than the tissues of the extremity, encircling the extremity and sealed to the receptacle and having a recess, a pneumatically permeable wall for the sealing member communicating with the recess and arranged proximately to `face the skin of the extremity, and means for subjecting the recess to suction to suck the skin, in a generally radial direction, away from the adjacent portion of the body extremity, into, and to maintain it in, sealing contact with the sealing member.

l 6. The combination with a receptacle having an opening through which an extremity of a living body extends into the interior of the receptacle'ffor subjection to the pressure within the receptacle, and means for subjecting the interior of the receptacle to varying abatmospheric pressures, of means for eiecting a duid-tight seal between the receptacle and the body extremity, said means comprising a relatively rigid annular sealing member encircling the extremity and sealed to the receptacle and having a pneumatically permeable side proximately facing the skin of the extremity, a recess in the sealing member communicating with vthe permeable side and means for subjecting the recess to suction to suck the skin, more or less radially away from the body extremity, into, and to maintain it in, sealing contact with the sealing member, the degree of suction in the recess being different from the degree of abatmospheric pressure presently within the receptacle.

'7. The combination of a receptacle, means for lsubjecting its interior to abatmospheric pressure,

an opening in the receptacle through which a limb of Aa human body may pass for subjecting the limb to the interior pressure, a cuff sealed to the rreceptacle and encircling the limb at the margin of its exposure to the interior suction, and means for sucking the skin of the limb away from the limb and into sealing contact with the cuff, whereby the cuir is non-constrictive of vascular circulation within the leg.

8. A means for effecting a gas-tight seal between the wall of an opening into a primary treat- 'v ment receptacle and a. portion of living tissue exposed to the interior of the receptacle through the opening thereof, said means comprising a relatively rigid secondary recessed sealing cham- 4 ber member framing the opening into the receptacleithrough which the tissue is exposed, said member havingan open side which may be .the portion to the-interior of a treatment cham- Cil ber by an opening thereinto, subjecting the chamber to abatmospheric treatment pressure, and pulling the proximate surface of said body portion into sealing contact with the margin of the opening by subjecting such surface to negative pressure different from the abatmospheric pressure in the treatment chamber.

10. 'I'he combination of a receptacle constituting a pneumatic treatment chamber subject to abatmospheric treatment pressure and having an opening for exposing a portion of a body member to the treatment chamber, a sealing ring around the opening sealed to the receptacle and comprising a lateral skin-engaging face, having a pair of spaced annular imperforate sealing margins, directed more or less flatwise against the annular area of skin bounding the portion exposed to the chamber through the opening, and passage means subjecting to suction portions of the skin-engaging face intermediate the spaced sealing margins for holding the skin in sealing engagement with thesealing ring.

11. The combination of a receptacle constituting a treatment chamber subject to abatmospheric pressure and having an opening for exposing a portion of a body member to the treatment chainber, a sealing ring having a. skin-engaging face for application more or less flatwise to the body portion, a flexible sleeve sealing the ring to the receptacle, and a pneumatically permeable annular slot in the skin-engaging face of the sealing ring, and passage means for subjecting the slot to suction for holding the proximate skin in 'sealing contact with the sealing ring.

12. The combination of a receptacle constituting a treatment chamber subject to abatmospheric pressure and having an opening for exposing a portion of a body member to the treatment chamber, a sealing ring having a skin-engaging face for application more or less flatwise to the body portion, a flexible sleeve sealing the ring to the receptacle, and a pneumatically permeable annular slot in the skin-engaging face of the sealing ring, passage means for subjecting the slot to suction for holding the proximate skin in sealing contact with the sealing ring, and adjustable positioning means interposed between the receptacle.

and the sealing ring for conforming the sealing ring to predetermined fixed non-planar contour whereby the skin-engaging face of the sealing ring may be conformed tothe body surface.

13. The combination of a receptacle constituting a treatment chamber subject to abatmospheric pressure and having an opening for exposing a portion of a body member to the treat-l ment chamber, a sealing ring having a skin-engaging face for application more or less atwise to the body portion, a flexible sleeve sealing the ring to the receptacle, and a pneurnaticalljr permeable'annular slot in the skin-engaging face of the sealing ring, passage means for subjecting the slot to suction for holding the proximate skin in sealing contact with the sealing ring, a. fixed support, and ladjustable positioning means for the sealing ring for conforming the sealing ring to predetermined fixed non-planar contour whereby the skin-engaging face of the sealing ring may be conformed to the body surface, the adjustable positioning means being interposed between the sealing ring and the support whereby the said proximate skin may be drawn away from the support upon which the body rests.

14. The combination of a receptacle 'constituting a treatment chamber subject to abatmospheric pressure and having an opening for exposing a portion of a body member to the treatment chamber, a sealing ring around the opening sealed to the receptacle and having a lateral skin-engaging face directed more or less atwise against theannular area of skin bounding the portion exposedto the chamber through the opening, passage means subjecting the intermediate portion of the skin-engaging face to suction for holding the skin in sealing engagement with the sealing ring, and a support for the sealing ring independent of the body.

l5. Themethod of sealing a pneumatic treatment chamber to the skin bounding a body portion exposed to the chamber which consists in supporting a sealing ring independently of the body in -contoured position conforming to the body area and sucking the proximate skin into sealing contact with thering by suction of a degree independent of the pressure in the treatment chamber. v

16. A sealing ring of the class described formed of resilient rubber and having a skin-engaging annular face, a rec-ess in the face', means for subjecting the recess to suction, and a perforated metal wall extending across the recess and annularly conformed and-set back from the skinengaging face to constitute a skin support between the edges of the recess, -the edges of the metal wall being embedded in the rubber of the sealing ring.

17. A sealing ring ofthe classdescribed comprising -an annular skin-engaging face, an annular slot in the face defining spaced annular 'sealing edges, an annular recess back of the skinto face the surface of the body of the patient,

means connected to the receptacle for periodically varying the abatmospheric pressure to which the exposed portion of the patients body is subjected, and means for-applying a continuous suction to the sealing ring to cause the skin of the patient adjacent the margin of the opening in the receptacle to adhere over the open side of the sealing ring and thereby seal the receptacle tothe patient. 1

' 19. Therapeutic apparatus comprising a receptacle having an opening through which a portion of the body of a patient maybe exposed fer subjection to uid presslu'e treatment, a sealing ring framing the opening in the receptacle,

said sealing ring having an open side to face the surface of the body of the patient about the opening in the receptacle, means for periodically and alternately applying positive pressure and -suction'to the receptacle to subject thereto the exposed portion of the patients body, and means lfor applying'a sustained suctionto the sealing ring to cause the skin of the patient adjacent the margin of the opening in the receptacle to adhere over the open side of the sealing ringregardless of the variations of pressure condi-v tions within the receptacle.

SIMON BENSON.

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