US2398520A - Adjustable liquid sealed pump - Google Patents

Description

April 1946. a w. CLEMENTS 2,398,520

VADJUSTABLE LIQUID SEALED rum Original Filed Feb. 15, 1940 2 Sheets-Sheet l 5s 8/ 32 ms 7 67 66 m I43 0 I06 M 7/ 85 9 umm In 42 as 29 15 9 o I 654. g, "I00 as 7 I02 as 93 r 9 100, J, fi 7 INVENTOR 9/ ERNEST w. CITEMENYIS ATTORNEY April 16, 1946. E. WJCLEMENTS 2,398,520 ApLIusTABLE LIQUID SEALED PUMP Original Filed Feb. 15,, 1940 2 Sheets-Sheet 2 o o 7/- 14s 8/ o 105 o 129 I38 I30 35 0 Q v I a 00 INVENTOR L /24- I s ERNEST w awn rs 1 I 54 I fi/M ATTORNEY Patented Apr. 16, 1946 ADJUSTABLE LIQUID SEALED PUMP Ernest W. Clements, Kansas City, Kans., assignor to Andrew A. Kramer, Kansas City, Mo.

Original application February 15, 1940, Serial No. 319,091. Divided and this application July 10, 1942, Serial No. 450,375 r 7 Claims. 60-625) My invention relates to pumps, and more particularly to an adjustable liquid sealed pump.

This is a division of my co-pending application Serial No. 319,091, filed February 15, 1940, on Respirator, and now abandoned.

My'pump is particularly adapted for use for varying the air pressure in respirators and is so constructed and arranged that the duration of the alternate pressure and vacuum, or similar pressure variations, in the respirator chamber, may be controlled, as well as the length of time that each pressure increasing and pressure decreasing operation requires.

It is accordingly a purpose of my invention to provide a driving mechanism for pumping means for varying the pressure in a chamber, that comprises telescoping means including a member fixed to the chamber and wide open at the opposite ends thereof, and a reciprocable member telescopically related to said first mentioned member, with liquid sealingmeans for the telescopic joint between said members, which is provided with means for adjusting the length of the stroke of the reciprocable member and the rate of reciprocation thereof.

It is a further purpose of my invention to provide a driving mechanism for pumping means of the above mentioned character that requires little power for the operation thereof, said pumping means comprising a reciprocable member which is reciprocated by means of a rocker arm, or walking beam, that is provided with means for counterbalancing the weight of the movable pumping member.

It is a further purpose of my invention to provide means for operating the walking beam or rocker arm for reciprocating said pumping member, which comprises rotatable driving means and means for varying the rate of rotation of the driving means, whereby variable speeds are possible, varying between 10 and 30 reciprocations per minute, with an infinite number of graduations between these limits.

In a respirator it is also desirable to provide means for obtaining a variation in the duration of the length of. the alternate increasing and de creasing pressures in the chamber, and the stroke of the pump or of the reciprocable member thereof is accordingly adjustable to accomplish this purpose. It is accordingly a purpose of my invention to provide a pump of the above mentioned character in which the stroke of the reciprocable member can be varied to any desired extent between predetermined limits, comprising adjusting means that are self-locking so as to. maintain; the

stroke of the desired length after the adjustment has been accomplished, said adjusting means,

preferably, comprising means for varying the throw of a crank member driven by rotatable driving means, by adjusting the position of apivot connection between said crank and a link connecting said crank and the rocker arm.

It is a further purpose of my invention to provide a pump that can be readily driven either by power or hand, an auxiliary hand drive being provided in case of power failure, or where power is not available, the change from power to mechanical drive, and vice versa, being made by a simple adjustment, which comprises means that are capable of being adjustable by any unskilled person, such as a nurse, or other attendant at a hospital not familiar with mechanics.

It is a further purpose of my invention to provide a liquid sealed pump which may be operated with any suitable liquid that may be available, preferably, an odorless, non-volatile liquid, and which is so constructed and arranged that a minimum amount of liquid is required for sealing the pump, which will not readily be evaporated or escape from the well provided therefor in the reciprocable member. In the normal use of the pump for varying air pressures in a respirator chamber, this is of great advantage, as the pump is always ready for instant use, regardless of the length of time that it hasbeen out ofservice, and there is nothing about the same that can get out of order and at the same time a gentle movement of air in and out of the respirator chamber takes place, which is more I nearly like the normal humanbreathing action than where other types of pumping devices, such as have been previously provided, are utilized. Due to the fact that the pumping device is connected wide open to the chamber, a much greater volume of air is acted on by the pump in proportion to the capacity of the chamber, than where relatively high pressures in small quantities of air are created by means of bellows, diaphragms, or ordinary piston pumps, my pump having a very large diameter, or bore, and a very short stroke relative to the bore, to provide the desired pumping action similar to a breathing action.

Preferably, the various means comprises self locking means, simple in operation and which will not come out of adjustment unintentionally, re maining in the particular position until reset to a different position. I

Other objects and advantages of my invention will appear as the description of the drawings proceeds. I desireto have it understood, however,

that I do not intend to limit myself to the particular details shown or described, except as defined in the claims.

In the drawings:

Fig. l is a side elevation of my improved pump applied to a respirator, which is partly broken I away.

Fig. 2" is an enlarged 'elevational view partly broken away, of the driving means for the pumping means.

Fig. 3 is an elevational view of aportionof the driving mechanism as viewed from the right handendofFig.2.

Fig. 4 is a section taken on the Fig. 5 on a slightly enlarged scale;

Fig. 5 is a sectional view through a portionof the driving mechanism taken substantially on the line 5-5 of Fig. 2. I

Fig. 6 is a sectional view taken on the line 6-6 of Fig.1. 7

Fig. '7 is a section taken on the line 1-1 of Fig. 3', and

line 4-4 er ards 19 extending between the body portion 28 and the base 54. The bifurcations, or arms I2 of said member H are provided with links 13 that connect the same with headed pivot members M, provided on brackets I5 fixed on the member 51. Said links are provided with bearing portions 16 rotatable on the headed members 14 and with suitable bearing portions 11, that receive the Fig. 8 is an enlarged fragmentary sectional view.

showing the 'sealingi'means. and connection betweenthe walking beam and reciprocable member corresponding to the left side of Fig. 6.

Referring in detail to the drawings, my improved pumpis shown as being provided on a respirator thathas a body portion 50, which is mounted onsuitable legs or posts extending from a base 54, said respiratorbeing provided with suitable casters or rollers on the legs thereof and on the base, as will be evident from the drawings,

headed pivot members I8 that pivotally connect said links with the arms 12 of the rocker arm, or walking beam H. v

It willbe obviousthat the reciprocable member 5! will be moved up and down as the member H is oscillated about its pivots 89 fixed on the standards I9. Means is providedfor counterbalancing the weight of the member 5! about said pivots 88, so that a minimum amount of power will be required for reciprocating said member 51, said counter-balancing means comprising a V rod-like extension 8| on themember H, on which but the particular mounting of the respirator is of no importance as far as the pump structure is concerned, except that the variations in pressure in the respirator-are controlled by means of the liquid sealed pumping means, and that the tubular member 55 forming the stationary tubular member of the pump, depends from the body portion 58 and is rigidly secured thereto in liquid tight relation, communicating with the body portion through a wide unrestricted opening 56 of substantially the cross sectional area of the tubular member 55, which is shown as being an open ended cylinder. Cooperating with said tubular member 55 is a reciprocablepumping member 51, which is, preferably, provided with an inner cylindricalwall .58 and an outer cylindrical wall 59, a transverse wall 89 being provided, closing the end thereof within the top edge of the cylindrical wall 58, and a bottom transverse wall 8! of aring-like character being provided, connecting the bottom edges of the cylindrical walls 58 and 59. A piston is thus provided thathas an end wall 69 and an annular channel, or well, therein extending around the same that receives the bottom edge of the tubular member 55, and which is filled witha liquid 62 to such an extent that the bottom edge of the member 55 will always be under-the level of the liquid, so that said liquid forms a seal between the wall 55 and the piston, or reciprocable member 51. 7

A flexible gasket member 83 .is also, preferably, provided, that engages the member 55 and is clamped on an inwardly directed flange 64 on the member 51, which has'a depending lip 55, the clamping being accomplished by means of q a clamping ring 66, and suitable securing elements 5; extending through the fiange 84 and said ring 8 Suitable mechanism is provided for reciprocating the member 51 and means is also, preferably, provided for preventing rotational movements of the member 51 relative to the member 55 coma counterweight 82 is adjustably mounted, said counterweight being shown as being held in adjusted position by means of suitable set screws 83, (see Fig. 2), said rod-like member being provided with a stop flange 84 thereon to prevent accidental disengagement of the weight 82 from the member 8|, a washer being shown as providing said flange, the same being held in position by means of a nut 52 engaging a reduced end portion of the member 8|.

The stroke of the member 51 is varied by varying the amplitude of the oscillation of the member H, as will be described below. The number of reciprocations of the member 51 per minute is controlled by a variable speed drive mechanism, which will be described below.

A motor 85 drives a pulley 88 through a suitable variable speed pulley device which may be of any well known standard type. Said pulley 86 is provided with a V-groove for receiving the V-belt 88. Said V-belt 88 operates over the variable speed pulley device, comprising a pair of pulley members 89 that are beveled on their inner faces to receive the belt 88 between them, and which are provided with suitable resilient means tending to move the members 89 toward eachother, the pulley operating in a manner such that the eflfective diameter thereof is dependent upon the depth to which the V-belt 88 enters between the members 89, and this is again dependent upon the tension put on the belt 88, which ctson the resilient means to force the members 89 apart in a well known manner. Means is provided for adjusting the variable speed, mechanism thus provided by means of the variable speed pulley device 89, which broadly comprises means for varying the spacing between the pulley 88 and the members 89.

Said meanscompri'ses a suitable bracket, such as the angle member 99 fixed on the base 9| through which a pair of guide rods 92 extend, which also extend through suitable openings in a pair of channel members93 secured together by a top plate 94 and'forming a mounting for thevariablespeed pulley device comprising the nally adjustable on the rods 92 and on the base S, which is fixed on the base 54, and, the particular adjusted position thereof is determined by means of ascrew-threaded rod-like member 95, (see Fig. 7) which is screw-threadedly received within an internally screw-threaded nut 96, that is fixed to one of the members 93, by welding or otherwise, said rod-like member 95 being held against longitudinal movement through the member 90 by means of a collar 98 on the rod 95 and the shoulder formed by an extension on the enlarged hub on the hand wheel 99, engaging opposite sides of the member 90.

7 her I09 comprises a pair of arcuate shoes H2 A spring 9'! is held under compression between I The shaft of the pulley 86 being fixed relative to the'base 9I, as will 'be obvious, the move ment of the variable speed pulley device 99 on the base 9! will adjust the spacing of the members 86 and 89, and thus vary the speed of the shaft carrying the pulley 86. The motor 05, which carries the variable speed pulley device 89 on the shaft is, of course, also mounted on the movable base made up of the members 93 and 94. The shaft that carries the pulley 86 is the input shaft of a speed reduction device 01 of a standard type, which has a base member I00, that is mounted on the member 9I, in fixed position. It will accordingly be obvious that the position to which the movable base, made up of the members 93 and 94, is adjusted by means of the hand wheel 99 will determine the speed at which thesprocket IOI on the output end of the speed reducer 81 will rotate.

A chain I02, (see Fig. 2), that operates over the sprocket IOI, also operates over a sprocket I03, (see Fig. 5), which is loosely mounted on the shaft I04 so that said sprocket I03 can rotate on the shaft I04 when desired. Means is provided for coupling the sprocket I03 to the shaft I04, which will be described below. A sprocket I05, (see Figs. 2 and 5), is mounted in a similar manner to that of the sprocket I03 on the shaft I04, and this sprocket has a sprocket chain I06 operating over the same, which operates over a sprocket I0I rotating with the crank I08, the sprocket I05 being held on said shaft by the collar 53.

Means is provided for connecting either the sprocket I03 or the sprocket I05 with the shaft I 04, so as to reciprocate the pumping mechanism provided, this being dependent upon whether it is desired to operate the device by manual means or by means of the motor 85, or because of the necessity of operating the respirator by means of the hand crank in case of power failure. Said means comprises a shiftable clutch member I09, which is keyed on the shaft I04, so as to rotate therewith, but is slidable lengthwise of said shaft. Said shiftable clutch member is provided with alternating projections and recesses that cooperate with similar projections and recesses on either the member I05 or the member I 03, depending upon the position of the shiftable clutch member I09, to rotate the member I09 either as a unit with the member I03 or as a unit with the member I05. Said recesses are indicated by the numeral I I0 and the projections bythe numeral III in Fig. 5.

The shifting mechanism for the clutch memthat operate in the groove II 3 on the member I09, said shoes Il2 being mounted on the arms II 4 of a shifting member, so that these can adjust themselves to the position of said shifting member about its pivot II6 without binding in the groove in the clutch member I09.

A spool-like member I20 having a pair of flanges I2I, that are located one on each side of the shiftingmember is internally threaded to receive the {screw-threads on the threaded rodlike member I22, Said spool-like member I20 has a forward extension I23, which has a handle I24 thereon, which is provided forrotating the spool-like member to adjust the same on the screw-threaded rod-like member I22, the internal threads in said spool and extension being indicated by the numeral I25. The threaded-rodlike member I22 has a head I26 thereon that IS fixed to the wall I21 of the base of the bearing member I28 mounted on the base 9I, so that it will not rotate.

Thus rotation of the member I24 will move the spool-like member I20 toward and away from the wall I21 and thus lock the shifting member II9 on its pivot II6 to adjust the clutchmember I09 to a position such that it will either be in engagement with the motor driven sprocket I03 or the manually driven sprocket I05 to rotate the shaft I04.

The shaft I04 is mounted on the bearing member I28 and has fixed thereon to rotate therewith a tubular crank member I29, said crank member being provided with reinforcing means I30 at its point f securement to the shaft I04. Said member I29 has a pair of fiat faces I32 thereon, that lie opposite each other and act as guides for a nut-like block I33, which will be described more in detail below. A shaft I34 is mounted rotatably in the end walls I35 and I36 of the tubular member I29, and a collar I31 and a crank I38, fixed to the opposite ends thereof, hold said shaft I34 in assembled position in the tubular crank member I29 against endwise movement as the same the crank I30 will adjust the screw-threaded nut,

or block,,I33 lengthwise on the shaft I34 to any desired position thereof. A pivot member I4I projects from the nut, or block, I33 and has one end of the crank I42 pivotally mounted thereon. The axis of the pivot MI is so located relative to the end of the block I33 nearest the wall I36 that when said block I33 is in its one extreme adjusted position, with one end wall thereof in engagement with the wall I30, the axis of said member I4I will be in alignment with the'axis of the shaft I04, and accordingly the arm I42 will have the end thereof receiving the pivot I41 lying on the center line of the shaft I04.

Upon reference to Figs. 2 and 5 it will be obvious that when such is the case-the arm, or link, I 42 will cause no oscillation of the rocker arm or walking beam II, as the position of the pivot I43 and that of the pivot-I4I will not change as the shaft I04 rotates. It will further be obvious that the further the block, or nut, I33 is moved from this position by rotation of the crank I39 the greater the distance between the center line of the shaft I04 and the axis of'theshaft I4I,

.ing action of the patient in the chamber.

link I42 pivoted on the pivot member MI in a circle of a radius dependent upon the position of said nut, or block, I33 and thus the amplitude of the oscillation of the rocker arm or walking beam II, will be increased the further the nut, or block, I33 is from the end I36' -o f the tubular crankmember I29. It will also be obvious that due to the long thread in the nut I33 in engagement with the threads I39 of the shaft I34, an accurate location of the pivot II can be established, and furthermore that self-locking adjusting means for this pivot is thus provided. Obviously the stroke of the member 51 is determined by the amplitude of the reciprocation of the member II, as above mentioned.

The purpose of the device being to provide a pump'for creating pressure changes in a respiratorchamber, such as the chamber 50, it is necessary in order to match as closely as possiblethe breathing action of a human being, to provide a series of duplicate pressure changes in the chamber 50 that have not only the frequency of the increasesand decreases in pressure thereof equal to the number of respirations per minute of the patient, but that each of these duplicate pressure changes be such as to produce as nearly as possible the peculiarities of the breath- In order to accomplish this, it is necessary that the pressure in the chamber surrounding the chest of the patient changes in such a way as to cause an -inspiration as nearly similar to that of the particular patient in the chamber as can be produced, and an expiration by change in the pressure of the chest wall that is also substantially the same as would be naturally produced by that particular patient. The actual inspiration and actual expiration are of different lengths with different patients, depending upon the peculiarities of that patient, and are not in any manner directly related to the rate of respiration. However, each normal inspiration of a givenrpatient is the same each time that it takes place, that is, each inspiration is the same as every other inspiration, and each expiration is the same as every other expiration. Alsothe number of respirations per minute is the same under normal conditions forthat particular patient over long periods of time. The character of the pressure changes found by experiment and study to be necessary to get the closest approximation to the characteristic manner in which a'human being breathes in and breathes out air, are those that would be produced in a closed rigid walled chamher if a rigid end wallof that chamber were moved part of the way toward the opposite end wall and back again in the manner of a piston driven by a crank, this producing pressure changes that at first take place slowly, then more rapidly as the middle of the stroke is reached, and then gradually more slowly until the opposite end of the stroke is reached, due to the fact, of course, that the crank is rotating and the connection of the piston with the crank moves in a circular path, while the crank moves ina straight line. v

Due to the provision of the open ended cylindrical member 55 in wide open communication with the chamber 59, the reciprocating movements of the piston having the transverse wall will produce the same character of pressure changes in the chamber50 as if an end wall of the chamber 50 were moved back and forth in the manner above stated, as the cylindrical resulting in a rotationof the lower end of the member 55 is a continuation or adjunct of the member 50. The movement of the piston member or pumping member 51 is accomplished normally by means of the motor by a positive driving connection, which positively moves the member 51 in response to the rotation of the crank'member I29, so as to produce the same characteristics in the movement of the member 51 in both directions, as would be true if the crank I29 were directly connected with the reciprocable member 51. The drive is from the motor 85 through the variable speed pulley device 89 and the peed reduction device 81 to drive the sprocket IilI, which in turn drives the chain I02 to rotate the sprocket I03 on the shaft I04 carrying said crank I29. The crank I29 oscillates the walking beam II through the link I42, which reciprocates the piston member 5! through the link connection I3. The amplitude of the movement'of the walking beam and thus the stroke of the piston 51 is adjusted by adjusting the position of the pivot MI by means ofthe crank I38 and the rate of reciprocation of the member 51 is adjusted by means of the adjustment of the variable speed pulley device 89 by means of the hand wheel 99 so as to move the pair of pulleys 89 toward or away from the pulley 86 to thus cause the belt to ride either closer to the periphery or nearer to the center of rotation of said variable speed device 89.

When a patient is placed in the chamber 50 the speed of the device is adjusted to obtain as nearly as can be estimated the frequency of reciprocation of the member 51 to that at which the patient is assumed to breathe normally, and the stroke of the membe 51 is adjusted by means of the crank I38 to a length that, from the characteristics of the patient, appears to. be about the right stroke for that patient. This, of course, depends upon the chest capacity of the patient, as well as the normal chest expansion and other peculiarities of the breathing of the patient. A physician can readily determine from the actions of the patient in the respirator, even if not entirely conscious, whether the pressure changes in the chamber 50 are normal in frequency and in other characteristics to those of the patient, as the patient will attempt to fight the action of the machine if it is not proper, or will otherwise show discomfort or annoyance. By adjustment of the member I38 and the member 99 the exact frequency and length of stroke that will be satisfactory for the particular patient can be established. As the adjusting means operated by the members 99 and I38 are self locking and will remain in adjusted position, the stroke length and stroke frequency will be maintained the same, as long as that patient is in the chamber 50, this usually being for great lengths of time if the patient survives the first few hours or first few days in the respirator while desperately ill.

7 As the device is used over such great periods of time ordinarily, it is quite possible that an emergency will arise when there is no power temporarily available to operate the motor 95, and if such an emergency develops the movable clutch member I09 is shifted from the position shown in Fig. 5, which is its normal position,

so that the same engages the sprocket I05, and

the crank I00 is rotated manually the same number of revolutions per minute that theshaft I04 has been driven through the drive from the motor 89, the stroke of the piston remaining the same, as the adjustment of the pivot member I4I on the member I29 does not have to be disturbed at all to ,make the change inmotive power from power. drive to manual drive. All of the adjustingi means are so constructed that any person without any mechanical ability can operate the same to adjust thelength of stroke, the frequency thereof, or to shift from manual'to power drive,

or vice versa, by turning a handle or other operating member, thus enabling a physician or nurse by mereobservationof the patient to bring the device in proper adjustment without the neces-,

sity of any mechanical ability, and enabling a nurse or other person not skilled in mechanics to shift to manual operation of the device when an emergency develops, without any instruction except to rotate the clutch operating member I24 to shift to the crank drive and to then rosure in a chamber, but one that has certain characteristics which can be changed by adjusting the length of the stroke, but all of which are of the same general character, that of a piston moving in a closed chamber or cylinder through a stroke only part of the length of the chamber or cylinder. The actual pressure changes are very small and the liquid seal provided does not change very materially in level either on the inside or outside of the cylindrical wall 55 durin the strokes of the member 51.

What I claim is:

1. A device of the character described having a large bore and relatively short stroke, comprising a rigid tubular member wide open at its onposed ends, a reciprocable member telescopically related to said tubular member having spaced inner and outer rigid tubular Wall portions connected by a, transverse wall extending between the same at the bottom thereof to provide an an nular well receiving said tubular member and having an imperforate flat transverse end wall extending across the upper end of said inner tubular wall to close said end thereof, a sealing liquid in said well, and means for reciprocating said reciprocable member, comprising lever having a forked portion embracing said reciprocable member and mounted to pivot about an axis between the ends thereof, driving means connected with said lever for pivotally rocking the same about said axis in both directions, and rigid links pivotally connected with said reciprocable member and the forks of said lever adjacent one end thereof.

2. A device of the character described having a large bore and relatively short stroke, comprising a rigid tubular member wide open at its opposed ends, a reciprocable member telescopically related to said tubular member having spaced inner and outer rigid tubular wall portions connected by a transverse wall extending between the same at the bottom thereof to provide an annular well receiving said tubular member and having an imperforate flat transverse end wall extending across the upper end of said inner tubular wall to close said end thereof, a sealing liquid in said well, means for reciprocating said reciprocable member, comprising a lever mounted to pivot about an axis between the ends thereof, driving means connected with said lever for pivotally rocking the same about said axis in both directions, and short rigid links pivotally connected with said reciprocable member and the A device is thus provided that not only provides for an alternate increase and decrease in presforks of said lever adjacent one end thereof, and

guiding means externally and eccentrically of said reciprocable member for holding saidreciprocable member from rotation about its axis.

x 3. A device of the character described having a large bore and relatively short stroke, comprising a rigid tubular member wide open at its opposed ends, a reciprocable member telescopically related to said tubular member having spaced inner and outer rigid tubular wall portions connected by a transverse Wall extending between the same at the bottom thereof to provide an annular well receiving said tubular member and having an imperforate flat transverse end wall extending across the upper end of said inner tubular wall to close said end thereof, a sealing liquid in said Well, flexible sealing means for said well on said outer wall wipingly engaging said tubular member, and driving means for positively reciprocating said reciprocable member in both directions.

4. A device of the character described having a large bore and relatively short stroke, comprising a rigid tubular member wideopen at its opposed ends, a reciprocable member telescopically related to said tubular member having spaced inner and outer rigid tubular wall portions connected by a transverse wall extending between the same at the bottom thereof to provide an annular well receiving said tubular member and having an imperforate transverse end wall extending across the upper end of said inner tubular wall to close said end thereof, a sealing liquid in said well, means for reciprocating said reciprocable member, comprising a lever having a bifurcated porl tion providing a pair of arms embracing said relarge bore and relatively short stroke, comprising a rigid tubular member wide open at its opposed ends, a reciprocable member telescopically related to said tubular member having spaced inner and outer rigid tubular wall portions connected by a transverse wall extending between the same at the bottom thereof to provide an annular well receiving said tubular member and having an imperforate transverse end Wall extending across the upper end of said inner tubular wall to close said end thereof, a sealing liquid in said well, means for reciprocatingsaid reciprocable member, comprising a lever having a bifurcated portion providing a pair of arms embracing said reciprocable member, said lever being mounted to pivot about an axis closely adjacent said reciprocable'member, headed trunnions fixed on said reciprocable member between the ends thereof, short rigid links pivotally connected with said trunnions and with said arms adjacent the ends thereof, and driving means connected with said lever on the opposite side of said pivotal axis nected by a transverse wall extending between the same at the bottom thereof to provide an annular well receiving said tubular member and having an imperforate transverse end wall extending across the upper end of said inner tubular wall to close said end thereof, a sealing liquid ends thereof, a guide rod extending parallel to the axis of said reciprocable member externally thereof, a laterally extending bracket on said reciprocable member slidably engaged with said guide rod, and driving means connected with said lever on the opposite side of said pivotal axis from saidreciprocable member to positively rock said lever about said axis in both directions.

'7..A device of the character described having a large bore and relatively short stroke, comprising a rigid tubular member wide open at its 0D- posed ends, a reciprocable member telescopically related to said tubular member having spaced inner and outer rigid tubular wall portion connected by a transverse wall extending between the same at the bottom thereof to provide an annular well receiving said tubular member and having an imperforate flat transverse end wall extending across the upper end of said inner tubular wall to close said end thereof, a sealing liquid in said well, and means for positively reciprocating said reciprocable member in both directions, comprising a walking beam mounted to pivot about an axis between the ends there0f,-short rigid links connecting said reciprocable member with the said walking beam adjacent one end thereof, a reduced extension on said walking beam, at the other end thereof, a counterweight adjustably mounted on said reduced extension, and. means for rocking said walking beam.

ERNEST W. CLEMENTS.

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