US2235544A - Grease pump - Google Patents

Description

March 18, 1941. F. E. WOLD 2,235,544

GREASE PUMP Filed June 20 1938 3 shoets -sheet l /0 -ml I i 0 Ira filial frm lfjflald. E A i /28 f 1 FQE. WOLD March 18, 1941.

GREASE PUMP- Filed June 20 1935 3 Sheets-Sheet 2 w m. 4 4 v w m 9 M2 Patented Mar. 18, 1941 PATENT OFFICE GREASE PUMP Frank E. Wold, Santa Monica, Calla, asslgnor ct one-hall to Donald E. Wo'olard, ltcs dngeies County, Calii.-

Application June 20, 1938, Serial No. 'tlttiiE 4 Claims.

This invention has to do generally with pumps or the like, and is more particularly concerned with pumps especially well adapted for the delivery of relatively heavy greases used in the lubrication of motor vehicles, or in any situation where it is necessary'or desirable to inject grease under relatively high pressure between the parts to be lubricated.

In lubricating the shackles or other working parts of motor vehicles, it is preferable to use grease supplied in large cans and to pump the lubricant directly from those cans to the hose of a grease-gun adapted to be applied to pinfittings on the spring-shackles and the like. It is among the objects of this invention to provide a particularly eflicient, automatically operating pump for use in such a system, the pump continuously standing in readiness to apply delivery pressure to the grease the instant the outlet valve of the gun is opened, and continuing automatically to supply that pressure so long as the valve is held open. Y

I have provided a pumping unit which includes a relatively low pressure cylinder for motivating fluid,'such as air under pressure, the piston for that cylinder being operatively connected to a piston within a relatively high pressure cylinder, the entire unit being self-contained and so arranged that it may be lowered to and from a' position where the inlet to the high pressure cylinder lies below thegrease level' in the container. A self-contained high pressure line extends upwardly from the high pressure cylinder into connection with a hose which carries a usual valve-controlled grease gun.

The motivating fluid for the low pressure cylinder may be supplied by the usual air-pressure line such as is commonly present in service stations, the valves for controlling the passage of this air to and from the lower pressure cylinder being included in the pumping unit, as will presently be described.

The general arrangement is such that the in- 'stant the valve of the grease gun is opened. the

motivating fluid is eflective within the low pressure cylinder to reciprocate the high pressure piston ahd thus deliver grease under high presand such fluid as may leak, in spite of the precautionary measures, merely returns to the body of grease in the container, rather than discharging exteriorly in a manner to cause damage or unsightliness.

. the pistons at the opposite ends of their strokes;

An additional object of the invention is to provide a mechanism which is simple and sturdy of construction, and thus well adapted to withstand the extremely severe service conditions to which apparatus of this type is exposed. 5

I have also provided a novel valve-actuating mechanism for controlling the passage of motivating fluid to and from the low pressure cylinder. Certain of the broader features of this mechanism are shown and claimed in my copending application entitled Vibrator mech anism, filed October 26, 1936, Ser. No. 107,619, but additional features are here shown and claimed.

Other objects and features of the invention will be made apparent in the following detailed description, wherein reference is made to the accompanying drawings, in which:

Fig. l is a .side elevation showing an embodiment of my invention wherein the supporting cabinet and grease can are shown in section;

Fig. 2 is an enlarged section on line 22 of Fig. 1, or may be considered as a reduced section on line 2-2 of Fig. 4;

Fig. 3 is a view similar to Fig. 2 but showing Fig. 4 is an enlarged plan view of Fig. 2 but sectionally showing'the cap, the cap-attaching strap, and the valve-rod; while the snap-actuator lever is shown in a position midway between the positions it occupies in Figs. 2 and 3;

Fig. 5 is a section on broken line 55 of Fig. 4, being somewhat in the nature of a developed. sec tion;

Fig. 6 is a section taken mainly on line 5--6 oi Fig. 4. though the section through the valve is taken on line 8--t' of Fig. 4, and the snap actuator has been moved to the position of Fig. 2;

Fig. 7 is a section on line 1-1 of Fig. 4, but with the valverod omitted, and certain parts being shown in elevation:

Fig. 8 is a section on line 8-8 of Fig. i; i

Fig. 9 is an enlarged section on line 9-9 of Fig. 3; and

Fig. 10 is an enlarged and inverted iragmen- 45 tary perspective showing the foot-valve sleeve in its association with the supporting barrel.

Referring particularly to Figs. 1 and 2, I will first describe the general structure of the high and low pressure cylinders and their assembly.

Low pressure cylinder It, for receiving motivating fluid such as air under pressure, is made up of cylindrical tube H clamped by bolts I: between upper and lower cylinder heads l3 and 14, respectively, said bolts being angularly spaced 5;

about the exterior of tube H and extending between head flanges l3 and I4.

Head M has a depending, tubular extension l5 which takes the threaded end of housing or tubular spacing jacket I5, the lower end of said jacket having telescopic fit at H with the upper end-oi the relatively thick-walled barrel l8. The bore l9 of barrel l8 serves as the high pressure, grease cylinder.

In one aspect, jacket |5 may be considered as a continuation of head-extension l5, and in another aspect head-extension |5 may be taken as a continuation of jacket l5, considering the latvertical arrangement is not essential to the functioning of the elements specified, the terms vertically, upper and lower areused, not in a limitative sense, but merely to locate the parts relatively.

' As willlater appear, jacket I5 is not exposed to high internal fluid pressures and may therefore be relatively thin-walled and made of relatively inexpensive stock. To prevent the building-up of internal pressure within the Jacket due to leakage from the high pressure cylinder, the

jacket is preferably providediwith a vent port Piston rod 2| is made up of sections 22 and 23, section 23 being of less diameter than section 22 and its upper end fitting into the oversize socket 24 in the lower end of section 22. The sections are pinned together at 25, but there is sufflcient looseness of fit to allow the piston sections to accommodate themselves to the parts with which they coact, thus avoiding binding effects even though cylinders I and I8 are slightly misalined.

The upper-end of section 22 is axially bored at 25 and internally threaded to take tubular nut 21, the assembly 28, which makes up the lowpressure piston head, being clamped between head 29 of nut 21 and the upper end 38 of rod- P section 22. Piston head 28 includes alternately arranged metal disks 3| 32. 33, and cups 34, 35, of leather or other suitable material, a metal spacing sleeve 35 being interposed between plates 3| and 33 and being encircled by metal plate 32 and cups 34, 35.

Rod section 22 extends through packing 31 and gland 38 provided in the counterbore 38 of head I 4 and extension I; washer at the lower end of the counterbore closely fitting the rod section and serving as a stop-for the packing.

Rod section 23 extends, preferably with ground,

fit, through hardened bushing 45 which is held seated in counterbore 4| 01' barrel l8 by the overhanging head of bolt 42. This ground fit between rod and bushing dispenses with the need of packing between the rod and barrel, as it is suiiicientlysnug to prevent any major leakage, and such minor leakage as may occur at this point is not damaging since barrel [8 and housing l5 are disposed within the grease container, as will be described later, and the productsoi leakage will merely drain back into the container.

The lower end 43 of rod section 23 is adapted to be reciprocated through cylinder I9 and thus acts as a high pressure piston. The fit of piston 43 in cylinder 8 need not be as close as that between the piston or section 23 and bushing 40.

The standing valve assembly indicated generally at 44, is made up of a sleeve 45 slipped into counterbore 45 at the lower end of barrel I8, and tubular nut 41 which is threaded into that counterbore and detachably holds the sleeve in place,

. though the sleeve may have limited end-play becut up from the bottom of sleeve 45 (Fig.

The ends of the trunnions have portions which extend beyond the periphery of sleeve 45 into square-cut notches 51 in the defining wall of bore 45. The trunnions and the rounded portion 58' which connects them, have rotational bearing on the upper end face of nut 41 or, expressed otherwise, on seat 53 at one side of inlet port 52.

Sleeve 45 has a side outlet port 58, while its opposite side is cut away at 53' to prevent interference with the swinging of flap 54.

The entrance of the trunnion ends in notches 51 not only holds the flap from shifting in the direction oi the trunnion axis but also holds the flap and hence the sleeve against rotation with respect to barrel |8,'and thus maintains outlet port 58 in registration with port 58 which leads outlet 58, and so it is assured that the flap will close when the opening force is relieved therefrom, or. at least, upon initiation of the pressure stroke of piston 43. The fit of trunnions 55 in grooves or channels 55 prevents flap 54 from shitting laterally in the direction of the axis of port 58.

In assembling valve 44' with barrel l8, the barrel is turned upside down and sleeve is dropped into place so channels 58 register with notches 51, it thus being assured that ports 58 and 59 are in register. Flap 54, with the trunnions extending approximately diametrically across bore 41 is lowered until the trunnions engage end-face 52 of sleeve 45, whereupon the flap is shifted laterally to enter the trunnion ends in notches 51, thus allowing them to drop into channels 55. Nut 41 is then screwed in to hold the valve parts in assembly The lower end of high pressure pipe 52 extends, with annular clearance, through the upper end of bore 55, while the upper end of the pipe is threaded into cylindrical block 53 which is. in effect, an elbow. Block 53 is positioned within side bore 54 in head-extension l5, and its passageway 55 puts pipe 52 into communication with the outlet nipple 55 to which the usual high pressure hose 51 (Fig. 1) is connected as, for instance, by usual swivel joint 58. Any suitable type of grease gun, here conventionally per square inch applied to the upper piston, an

illustrated at 69 and whose outlet valve (not shown) is controlled by hand lever or tri'gger 10, is connected to the other end of the hose-by swivel joint ll A tubular sealing gland 12 is threaded through the lower end of bore 60, and has a conical seat 13 adapted to engage the lower and complementarily'tapered end 14 of pipe 62. The lower end of the gland has a screw-driver slot 15 whereby, when the lower end of bore 60 is cleared of all other ,'parts, the gland may be reached by a screw-driver for adjustment into tight engagement with pipe 62, thus providing a seal to prevent leakage around the outside of the pipe.

Threaded into the lower end of bore 60 is plug 16 having an upwardly opening bore TI, the upper end of the plug being fashioned as a conical seat 18 to receive a check-valve ball 19. The ball is adapted to play vertically w'ithin valve chamber 80 to and from its seat I8, the valve chamber being vertically defined by the spaced and opposed ends of gland l2 and plug 18.

The central portion 8| of plus 16 is of reduced diameter, thus providing an annular chamber 62 to which port 59 opens. A plurality of ports 83 are adapted to maintain chamber 82 and bore ll in communication.

Before describing the actuating mechanism for the control of the motivating-fluid valves, I will describe a preferred installation of the pump and the operation of the mechanism so farset forth. However, it will be understood that this showing of one type of installation is made for illustrative purposes and. is not to be considered as limitative on the other aspects of the invention.

I have provided a cabinet 85 (Fig. 1) with an open side 86. The top 81 has an openin 88 through which the lower end of the pump may be elevated from or lowered to place. When the pump, indicated as a whole at P, is lifted from the cabinet, a usual can or container as filled with grease G, may be slid through open side 86 into the position shown in Fig. 1, where its uncapped opening 89 lies directly beneath opening 88. Pump P is then lowered into the position of Fig. 1 the downwardly facing shoulder 90 of head-extension l coming to rest on top 81 and thus supporting the entire pump assembly on that top.

Assuming the pump to be in the condition of Fig. 3 and that motivating-fluid be admitted beneath piston 28, it will be apparent that the consequent up-stroke of piston 53 will cause a depression in cylinder i9, it resulting that valve 6t will be opened and grease will enter cylinder 9%. Upon subsequent downward movement of pistons 28 and 43, valve 64 is closed, and piston 43 forces the grease from cylinder l9 through ports 58, 59, chamber 82, ports 83, bore ll, check-valve l9, and chamber 80, passing thence through the bore of gland 12 into the pipe 52 and on to hose $7 and grease-gun 59. 1

It will be seen that due to the difierential existing between the effective cross-sectional areas of pistons 28 and 43, relatively low pressure applied to piston 28 will result'in the application of relatively high pressure to the grease in cylinder l9. While the following proportions are not controlling on the invention, in the illustrated embodiment the ratio of eiiective cross-sectional area of piston 28 to the effective cross-sectional area of piston 43 is about of the order of 43 to 1, so, with the relatively low air pressure of 100 lbs.

which would otherwise effectively resist entrance.

Now it will be seen that pipe 62 and block 63 are exposed to very high internal pressures,.and

therefore they are made of material which is well adapted to withstand the strains incident to those pressures. For instance, pipe 62 may be double strength pipe and block 63 ofmild steel.

.On the other hand, head-extension l5 and jacket M are not exposed directly to these internal pressural strains, and therefore may be constructed of.relatively light and cheap material. For instance, extension I5. may be cast iron, and jacket it; may be standard" pipe.

It will also be observed that leakage occurring within any part of the high pressure line up to the point where block 64 emerges from extension i5, will merely result in drippage back into the body of grease G. Yet in spite of the effective sealing of the high pressure line, it is a comparatively simple matter to disassemble the entire high pressure line and the various valves for pur-- poses of inspection or repair, and just as simple to reassemble them for subsequent use.

I will now describe the various valved passageways having to do with the controlled flow of motivating fluid into and out of the low pressure cylinder.

Extending upwardly from head i3 is a valve block 92 made up of post portion as and overhanging head portion 94. Extending vertically through head portion 94 are parallel valve or inlet chambers 95 and 96, which chambers are equally spaced from and at opposite sides of vertical plane K (Fig. 6). Plugs 91 and 98 close the upper ends of the chambers, while the lower ends of chambers 95 and as are defined by conical seats Hill and HH, respectively, which surround the I upper ends of vertical passages 12 and it, respectively. The lower ends of passages m2 and 403 are provided with conical valve seats we and E05, respectively, which taper oppositely from seats Hill and MI.

Valve balls Hi6 and ID! are pressed toward their respective seats by springs m8 and ,ess, while valve balls H0 and Hi are held beneath their respective seats by cam faces H2 and-ii3 on rock-camlM. The details of this cam will be later described, but it may be here noted that when the cam is in the position of Figs. 2 and 6, ball ill is held against its seat I05 by cam face H3, while ball III! is lowered from its seat Hid due to the relatively low position of cam face i i2.

Loosely fitting in passages Hi2 and W3, respectively, are tappet pins H5 and ill, these pins being of such length that when a given ball H0 or ill is seated'b-y cam M4, the overlying ball will be raised from its seat M0 or id! by the corresponding tappet. Such a condition is shown in connection with balls ill and H17 in Fig. 6, it being further noted that tappet H6 does not interfere Withthe seating of bail I06 when ball H0 is lowered fully from its seat Hi8.

Obviously, when cam H4 is rotated in a clockwise direction (as viewed in Fig. 6) to a position seating ball H0 and unseating ball I06, ball ill will be lowered from its seat and ball I01 will be lowered or spring-pressed to its seat. Seats Hi4 and 105 are of such vertical extent and the vertical separative movement between those seats and the underlying cam faces is so slight, that balls IIv and III are confined against bodily dislodgement.

For later convenience, ball I06 and its seat I00 will be considered together as making up inlet valve A; ball I I0 and its seat I04 as exhaust valve B; ball .I II and its seat I as exhaust valve C; and ball I01 and its seat IOI as inlet valve D. Thus, it will be seen that passages I02 and I03 each comprise a chamber having an inlet valve at its upper end and an outlet valve at its lower end.

Inlet passageway I leads from nipple I2I to valve chamber 95 (Fig. 5) nipple I2I beingconnected to a line I22 (Fig. 1) leading to a source (not shown) of motivating fluid such as air under pressure. Preferably, though notv necessarily, an oil cup I23 is introduced in this line and adapted to supply a small amount of oil to the air stream as it passes into nipple I2I, this 011 being thence carried by the air stream to the various working parts of .the valves. the valve-actuating mechanism and the piston and cylinder walls to maintain them always in a well lubricated condition.

Chambers 95 and 96 are maintained in constant communication by cross-passage I24 (Figs.

- 6 and 7), it following that chamber 96, as well as chamber 95, is normally filled with air'under Pressure. l

With the valves in the condition of Figs. 5, 6

and 8, air flows from chamber'96 through open valve D into chamber I03 whence it passes through passageway I25 (Fig. 8) into the upper end of cylinder I0, thus tending to depress piston 28. In order to allow such depression, the air below piston 28 is exhausted through passageway I21 in the lower cylinder head I4 (Fig. 5) said passageway leading to nipple I28 which, through unions I29, I30 and pipe I3I (Figs. 1 and 5) is connected .to nipple I32 which communicates with the lower end of passageways I 33 provided in valve-block 92. (Fig. 5). Passageway I33 opens to chamber I02, and exhaust air admitted thereto passes outwardly through valve B to the atmosphere by way of the' interior of cap or dome I34 and cap-vent I35 (Fig. 2).

The lower edge of cap I34 fits over annular bead I36 on flange I3, while screw I31 detachably holds the cap to inverted yoke I38 which, in turn, is held to flange I3 by the nuts on a pair of diametrically opposite bolts I2.

Upon rocking cam H4 in a clockwise direction, as viewed in Fig. 6) valves A and C will be opened and valves-B and D will be closed. As will be described. this cam and valve actuation occurs when the pistons are approximately at the bottom of their strokes (Fig. 3). 'I'hereupon, the motivating fluid is admitted beneath piston 28 through the following path; chamber 95, valve A, chamber I02, passageway I33,'pipe I3I, and passageway I21 (Fig. 5, although here the valves Aand B are in the position opposite those they would occupy .under such conditions). Air from above piston 28 is exhausted through the fol- The valve actuating means includes cam II4,

, which is mounted for oscillation or rocking movement on shaft I40, the latter beingheld rigidly in post-bore I by set screw I42 (Fig. '7). The axis of cam oscillation lies in vertical plane K (Fig. 6) and is thus midway between valves B and C. Mounted for oscillation on shaft I independently of cam I I4, is actuating lever I43 which has a hub portion I44 held in end engagement with cam II4 by cotter key I45, the wall I46 of post 93 limiting the movement of the cam-and-lever assembly to the left, as viewed in Fig. 7.

Hub I 44 is cut away at I 41 and I48 to provide vertically spaced, upper and lower, radially extending shoulders -I49 and I50, respectively, the arm I49 thus defined at top and bottom by these shoulders being centrally slotted at I50 to take the upper end of valve rod I5I (Figs. 2, 4 and 7, though the valve rod is omitted in Fig. 7). It will be seen that shoulders I49 and I50 are offset from the axis of lever-oscillation, so that force vertically applied thereto tends to move the hub angularly. In effect, of course, arm I49 may be considered as a lever which is so associated with actuating lever I43 that vertical movement of rod I5I is translated into angular movement of actuating lever I43.

Rod I5i extends through packing assembly I52 in cylinder head I3 and through the bore of nut 21 into bore 26. A terminal nut or head I53 on the rod provides an upwardly facing shoulder I54 adapted, at times, to contact the downwardly facing stop shoulder I55 presented by the lower end of tubular nut 21. An opposing stop shoulder I56 is formed by the bottom-defining wall of bore 26, which shoulder is adapted, at times, to be contacted by the lower end of rod I5I or the lower face of nut I53.

Threaded on rod I5I in opposition to shoulders I49 and I50, respectively, are nuts I51 and I58 which may be threadably adjusted along the rod to vary the timing of the actuator, as will later be apparent, lock nuts I59 and I60 serving to hold nuts I51 and I58, respectively, in adjusted position. i

It will be seen that piston rod section 22 and rod I5I are telescopically associated so theyare' cam II4 from the position of Fig. 2. or 6 to the position of Fig. 3, and vice-versath ereby actuating valves A, B, C and D, as has been described.

Actuators B and T are identical and they act together to rotate the cam in a given direction when they come into play; thereafter yieldably holding the cam in its new position until they again come into play to rotate the cam reversely. Only one of the actuators need be described in detail, but corresponding parts of the other will be given the same,but primed, reference numerals.

Actuator S comprises telescopically arranged plunger I10 and sleeve I", head I61 being in tegral with the outer end of the sleeve. Plunger I10 carries integral head I12 which is seated in socket I13 sunk in the peripheral face of cam II4. Sockets I13 and I13 are diametrically 0pposite one another.

In discussing the action of the actuator and control means therefor, I will refer to a certain "line of centers.. This line of centers is here indicated by the reference letter Y, and extends through the axis of rotation of cam H4 and the centers of the two outermost heads I81 and I83; or this line of centers may be considered as passing throughv the axis of rotation 01' lever I43 and the centers of sockets I85 and I66.

Compression springs I15 and I15 constantly tend relatively to extend the plungers and sleeves of the corresponding actuators. When piston 28 is at the upper end of its travel, the actuator parts occupy the positions indicated in Figs. 2

and 6, where, since heads I12 and I12 are oppositely offset from the line of centers Y, springs I15 and I15 exert such pressure on cam II4 as tends to rotate it in a counterclockwise direction, thus holding valve C tightly closed and valve D 'fully opened, while allowing valve B to remain open and valve A to remain closed.

The extent of angular movement of cam H4 in this direction, is, of course, limited by ball III in its position of engagement with seat I05, and it will be seen that subsequent clockwise movement of the cam will be limited by ball- I I8 in its position of engagement with seat I84. At

.the same time, it will be seen that by virtue of this arrangement, wear of the balls or their seats 4 is automatically compensated, for springs I15 and I15 will, in the event of suchwear, merely rotate the cam to a greater extent and thus move the balls through a suiiiciently greater distance to insure their ultimate seating.

Nowassume that the parts are in the position of Fig. 2 (except that valve 34 will probably have been closed by gravity) with air under pressure standing in cylinder I above piston 28 and with the high pressure line from cylinder I8 to gun 69 charged with grease. When the gun is applied to a lubricating fitting (not shown) and trigger it is actuated to open the gun-valve (not individually shown) the motivating fluid is imrepresents the position of parts when that limit is reached) shoulder I55 on nut 21 engages shoulder we on nut I53 and thus exerts a downward pull on valve rod I5I and, through nut I51 and lever I48, sets up counterclockwise movement of lever or yoke I43 (as viewed in Fig. 2). Since, at this time heads I12 and I12 do not move bodily, the initial pivotal movement of the yoke relatively collapses the telescopic-joints oi the actuators and thus causes further compression of springs I15, I. After the angular movement of lever I63 has carried the line of centers Y just past the position where the centers of heads I12 and I12 lie within that line, actuators S and T will act by the sudden extension of their springs to snap cam H4 in a clockwise direction to the position of Fig. .3. The sudden extension of the actuator springs will also snap lever I43 in a counterclockwise direction (as viewed in Fig. 3) and through lever I49 will snap rod I5I to its lowermost position (Fig. 3)

which accounts for the development of the vertical space indicated in Fig. 3 between shoulder I55 and shoulder. I54. The shock of lever-impact is absorbed, at least in part, by fatigue spring I88 which is held to the upper face of head I3 by the nut I8I on one of the bolts I2.

The snap-over of cam II4 reverses all valves A, B, C and D from the positions of Fig. 6,-resuiting in a reversal of the flow of motivating and exhaust fluid, as has been described, and

' piston 28 will be moved upwardly, a. new charge of grease following piston 43 into cylinder I9. Just before piston 28 reaches its upper limit of I5! will be pushed upwardly, nut I58 consequently thrustinglever I49' and hence lever I43 in a clockwise direction, as viewed in Fig. 3. As the line of centersY passes just beyond the centers of head I12 and I12, springs I15 and I15 become effective to extendtelescopic joints of the actuators and thus snap the cam H4 and lever I43 back to the position of Figs. 2 and 6, restoring valves A, B, C and D to their original positions, whereupon the motivating fluidis efiective again to depress piston 28 and thus to force piston 43 through its deliver stroke. In returning to the piston of Fig. 2, the shock of impact is taken from between lever I43 and cylinder head I3 by fatigue spring I82 (Figs. 4 and '1) which is held to the head by nut I83 on one of the bolts I2. I 7

Thus, reciprocation of pistons 28 and 43 continues, and grease is expelled under high pressure from gun 89 until the valve of that gun is closed, whereupon all parts of the pump come to rest, though they are left in condition to resume pumping action the instant the gun-valve is reopened.

It will be seen that with cam I I4 acting on the valves at points equally removed from oscillatory axis X, and with the snap-actuators applying their effective force to the cam at points sim ilarly related to that axis, the entire system is well balanced, thus contributing to even and posi-' tive action.

It is believed a full understanding of the invention will be had from the foregoing, but it will be understood that various changes in design, structure and arrangement may be made without departing from the spirit and scope of the appended claims.

I claim: a

1. In a device of the character described, a pair of vertically arranged cylinders, a tubular spacer structurally interconnecting the cylinders to hold them substantially in vertical alinement and at predetermined spacing, a pair of pistons, one in each cylinder, connected for coincident reciprocation, means whereby pressure fluid may be alternately admitted to and exhausted from the ends of the upper cylinder to reciprocate the pistons, there being a valved grease-inlet and a grease-outlet for the lower cylinder, both inlet and outlet being near the bottom of the lower cylinder, a check valve for the outlet, and a discharge line extending upwardly from said outlet and within the spacer.

2. In a device of the character described, a vertically arranged, upper cylinder having upper and lower heads, a tubular, axial extension depending from the lower head, a barrel supported at the lower end of .the extension and having a lower cylinder in substantial alinement with the upper cylinder, a pair of pistons, one in each cylinder, connected by a rod, extending through said extension, for coincident reciprocation,

means wherebyf pressure fluid may be-alternately admitted to and exhausted from the ends of the upper cylinder to reciprocate the pistons, there'being a valved inlet for the lower end or said lower cylinder, and there being a bore in said barrel parallel to the lower cylinder and in communicationtherewith, a discharge pipe extending upwardly from said bore and through the bore of said extension, means connecting the upper end of the pipe with delivery means located exteriorly or the pump, and a check valve preventing return flow from the delivery means toward the valved inlet.

3. In a device of the character described, a vertically arranged, upper cylinder having upper and lower heads, a tubular, axial extension depending from the lower head, a barrel supported at the lower end of the extension and having a lower cylinder in substantial alinement with the upper cylinder, a pair 01' pistons, one in each cylinder, connected by a rod, extending through said extension, for coincident reciprocation, means whereby pressure fluid may be alternately admitted to and exhausted from the ends of the upper cylinder to reciprocate the pistons, there being a valved inlet for the lower end of said lowercylinder, and there being abore in said barrel parallel to the lower cylinder and in communication therewith, a discharge pipe extending upwardly from said bore and through the bore of said extension, at check valve in said barrel bore below said pipe, and means connecting the upper end of the pipe with delivery means located exteriorly ot the pump.-

4. In a device of the character described, a vertically arranged, upper cylinder having upper and lower heads, a tubular, axial extension depending from the lower head, a barrel supported at the lower end oi the extension and having a lower cylinder in substantial alinement with the upper cylinder, a pair of pistons, one in each cylinder, connected by a rod, extending through saidextension, for coincident reciprocation, means whereby pressure fluid may be alternately admitted to and exhausted from the, ends of the upper cylinder to reciprocate the pistons, there being a valved inlet for the lower end 01 said lower cylinder, and therebeing a bore in said barrel parallel to the lower cylinder and in communication therewith, a discharge pipe extending upwardly from said bore and through the bore of said extension, and a member extending transversely through oneside of the upper end of the extension and having a bore opening at one end outwardly of the extension and opening at its other end to the pipe-bore at a point within the extension.

FRANK E. WOLD.

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