US2735586A

US2735586A - field

Info

Publication number: US2735586A
Authority: US
Publication date: 1956-02-21
Anticipated expiration: 1973-02-21

Description

Feb. 21, 1956 R. P. FlELD SEALED FoLLow-PLATE FOR LUBRICANT DIsPENsERs 2 Sheets-Sheet l Filed Jan. 18, 1954 JNVENTOR.

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SEALED FOLLOW-PLATE FOR LUBRICANT DISPENSERS 2 Sheets-Sheet 2 Feb. 21, 1956 Filed Jan. 18,

INVENTOR.

mmm/57s.

2,735,586 SEALED FOLLOW-PLATE FOR LUBRICANT DISPENSERS Richard P. Field, Cincinnati, Ohio, assignor to Balcrank,

Inc., Disney, near Marburg, Cincinnati, Ohio, a corporation of Ohio Application January 18, 1954, Serial No. 404,721 4 Claims. (Cl. 222-260) 'Ihis invention relates to lubricant pumps used in dispensing lubricant under pressure from a container and is directed particularly to an air sealing follow plate structure which rests upon the lubricant in the container and improves the operation of the pump.

Lubricant dispensing pumps utilizing a follow plate usually are mounted directly upon the container or drum in which the grease is shipped to the user. When placed in use, the cover of the shipping drum is removed and the dispensing pump is mounted directly upon the open top of the drum so as to dispense the grease or oil directly from the drum without further handling. present follow plate structure is intended particularly for use With the original shipping drums although it will be apparent from the disclosure that the structure may be used Without substantial change in lubricant dispensing pumps which include a container as an integral part of the pump structure. For the purpose of illustrating the principles of the invention, the follow plate structure is disclosed in its utility with the original grease shipping drum.

Dispensing pumps which utilize follow plates are widely used in service stations for feeding lubricant under pressure to the grease fittings or nipples of automotive Vehicles. The typical structure consists of the cylindrical grease drum, the grease pump having a cylinder or barrel projecting downwardly through the grease toward the bottom of the drum. The lower end of the pump cylinder includes an intake passageway which withdraws grease from the drum beneath the follow plate by suction und delivers it under pressure to a delivery conduit. in dispensing ordinary light greases, for example, cup grease which packs down readily, the conventional follow plate, which fits loosely in the drum and around the pump cylinder, is effective to follow the mass of grease and to wipe most of the grease from the wall of the container and cylinder so as to prevent excessive waste.

However, because of atmospheric pressure as the grease is sucked out, there is a tendency for air to break through the mass of grease from above the follow plate and to channel downwardly along the pump cylinder to its intake end. When this occurs, the pump'becomes air bound, requiring that it be removed from the drum to allow the grease to be packed down by hand. This tendency increases in pumping the heavier or more viscous grades of greases due to the increased flow resistance; moreover, even with light grade cup grease, it is practically impossible to completely empty the drum since the air usually breaks through as the grease level approaches the bottom of the drum. For this reason, it is customary to stop pumping before the drum is completely empty and to mount the pump upon a fresh drum of grease. A certain percentage of the grease of each drum thus may be wasted, or the residue may be scraped out by hand and placed in the fresh drum after it becomes partially emptied.

One of the primary objects of the invention has been to provide a follow plate structure which establishes an air seal with the wall of the drum and pump cylinder or barrel so as to eliminate the channeling of air under atmospheric pressure, thereby to provide more eflicient operation of the pump; also to allow the grease, whether light or heavy, to be pumped out substantially to the rates Patent The ice

bottom of the drum without channeling of air to the pump cylinder.

A further object has been to provide a follow plate structure which includes a sealing sleeve embracing the pump cylinder or barrel, the sleeve being collapsible lengthwise to compensate for the grease level in a full drum of grease, the sleeve expanding lengthwise as the follow plate moves downwardly to maintain an air seal as the follow plate approaches the bottom of the drum.

Described briefly, the present structure comprises a rigid follow plate disc fitting loosely within the drum and around the pump cylinder or barrel, the disc having a relatively thin walled fiexible rubber sleeve slidably embracing the pump cylinder so as to provide a seal between the disc and pump cylinder. The periphery of the disc includes a thin, flexible sealing strip providing an air seal with the internal wall surface of the drum. When the pump and follow plate are placed upon a full grease drum, the sealing sleeve is compressed length- Wise between the upper portion of the pump and follow plate, maintaining a seal relative to the pump cylinder, while the sealing strip seals the disc relative to the drum. As the pump is operated, there is a tendency for the grease to be sucked out from the area surrounding the intake passageway, leaving a vacuum in the drum below the follow plate. Since the follow plate provides an air seal, atmospheric pressure acting upon the sealed follow plate from above, forces it downwardly so as to eliminate the void as it is formed. As the follow plate moves downwardly, the tlexible sleeve straightens out while retaining its sealing engagement with the pump cylinder. In its final position near the bottom of the drum, the sleeve and sealing strip, by virtue of the sealing effect, allow practically all of the residual grease to be pumped out.

By utilizing a relatively thin walled flexible sleeve, a self-sealing action is provided by the sleeve relative to the pump cylinder, since atmospheric pressure tends to force the sleeve into intimate contact with the surface of the cylinder. The thin wall of the sleeve likewise makes it readily collapsible lengthwise so as to compensate for the limited space between the grease level of a fresh drum and top structure of the dispensing pump.

The peripheral sealing strip surrounding the follow plate disc extends outwardly a substantial distance from the edge of the disc to the wall of the drum. This strip is also relatively thin and highly flexible and therefore assumes an upwardly cupped Shape when the follow plate is placed in the drum. Atmospheric pressure acting upon the strip tends to force the edge of the strip into contact with the drum surface to provide the air seal. Being thin and flexible, the strip compensates for ditferences in the size of the drum and also yields readily to irregularities, such as bulges, in the drum surface without disrupting the air seal.

ln its preferred embodiment, the sleeve and sealing strip are confined between a pair of spaced discs which are clamped together to provide a rigid assembly. The discs may be constructed of light gauge sheet metal or of nonmetallic material, the discs being attached together preferably by staples to provide a clamping engagement with an edge portion of the sleeve and sealing strip.

Various other features and advantages of the invention are more fully disclosed in the following detailed description taken in conjunction with the drawings.

In the drawings:

Figure 1 is a Vertical sectional view of a hand operated grease dispensing pump mounted upon a full grease drum, with the present follow plate structure in Operating position within the drum.

Figure 2 is a fragmentary sectional view of the lower portion of the drum showing the follow plate structure at its lower limit of travel after the grease has been pumped from the drum.

Figure 3 is a top plan view illustrating the structural features of the follow plate.

Figure 4 is an enlarged fragmentary sectional view taken along line 4--4, Figure 3 further detailing the construction of the follow plate.

The Vfollow plate structure is disclosed in the drawings in relation to a portable lubricant dispensing pump, indicated generally at S which is mounted directly upon the top of a sheet metal grease shipping drum 6. Upon being placed in service as shown in Figure l, the lid or top of the drum is removed and the dispensing pump, with the follow plate 7, mounted upon it, is placed upon the drum with the pump barrel 8 projecting downwardly through the follow plate and grease toward the bottom of the drum. The grease is withdrawn from the lower portion of the drum by suction as described in detail later. The pump is supported in operating position upon the drum by a cover plate lt) which fits over and rests upon the open top of the drum. lt will be understood that the present hand operated pump is intended to illustrate the use of the invention and that the follow plate structure, without any change in the principle of Operation, is intended to be applied to other classes of pumps, whether hand or power operated.

Upon being installed on the drum, the pump barrel 8 projects through an opening in the center of the follow plate and an air seal is provided between the plate and barrel by a thin walled, flexible sleeve 11 formed of rubber or other material having the required characteristics. The sleeve has its lower end attached to the follow plate and has an upper portion slidably embracing the pump barrel. The outer periphery of the follow plate establishes a sliding air seal relative to the internal surface of the drum by means of a ilexible sealing strip 12 also formed of rubber or similar material.

When the fresh drum of grease is first placed in service, the follow plate rests upon the surface of the grease near the top of the drum (Figure l), with the sleeve collapsed lengthwise generally in accordion fashion. The sleeve normally Springs lengthwise, and as the grease is withdrawn from the drum, the sleeve straightens to its cylindrical shape shown in Figure 2. lt will be noted in Figure 2 that the sleeve maintains the seal until the follow plate reaches the bottom of the drum; it therefore allows practically all of the grease to be pumped from the bottom area of the container.

During operation of the pump, the grease is withdrawn by suction upwardly through the barrel and is delivered under pressure to a delivery fitting 13 at the upper end of the barrel. The fitting includes a ilexible conduit 14 which leads to a grease dispensing nozzle (not shown). The nozzle may be of any commercial type which provides a detacha'ole connection with the grease nipples of automotive Vehicles, industrial machines and farm equipment, the grease being forced under high pressure through the nipple and into the bearing. iln the present disclosure, the dispensing pump is intended to be used with a booster nozzle which includes a hand operated piston for discharging the grease at high pressure into the nipple. As the grease heneath the follow plate is sucked out by the pump, a vacuum is created beenath the sealed follow plate, forcing it downwardly upon the mass of grease. The present follow plate is of particular utility in pumping stiff grades of oils and greases which have limited flowability.

in pumping such luhricants with a conventional follow plate in the drum, there is a natural tendency, due to fiow resistance, for air to break through or channel past the follow plate and destroy the vacuum beneath it. The follow plate is then inetfective and the pump continues Operating but pumps air instead of grease. The pump may then become air bound, that is, air may be trapped between the piston and intake check valve where it is compressed during the downward or charging stroke and expanded during the delivery or upward stroke.

As the level of the grease in the drum decreases, the likelihood of an air column breaking through increases, since the resistance of the grease to passage of air becomes less as the mass of grease above the intake end of the pump decreases. This may occur several times while a given grade of lubricant is being pumped and each time, the operator must stop pumping and remedy the condition to avoid pumping air. As the lubricant level approaches the bottorn of the drum, these inten'uptions become more and more frequent; hence, it is customary to stop pumping before the drum is empty. The drum is then set -aside with a substantial residue of grease in its bottorn and the pump is mounted on a fresh drum. The residue may be wasted, but usually it is scraped out by hand and placed in the fresh drum after a sufiicient amount of lubricant vhas been pumped out of it. The extra handling takes a great deal of time and eifort and is naturally an objectionable procedure. The present follow plate structure, as indicated above, maintains the seal, allowing substantially all of the grease to be withdrawn and thus eliminates the interruptions in pumping and the waste of grease or loss of time in salvaging it.

Described in greater detail with reference to Figure l, the pump, which is selected to illustrate the principles of the invention, includes a pump cylinder 15 extending coaxially through the barrel 8. A piston 16 is slidably sealed within the cylinder and is reciprocated by the piston rod T7 in charging and delivery strokes. In the present example, the piston rod and piston are reciprocated by a hand lever 18 which has its forward end pivoted as at 29 to the upper end of the piston rod. The hand lever 18 is fulcrumed as at 21 upon the upper end of a link 22 which has Vits lower end pivotally connected as at 23 to a plate 24 mounted upon the cover plate 10.

During the upward stroke of piston 16, the grease is sucked into the lower end of cylinder 15 past a ball check valve 25 which seats within the constricted lower end 26 of the cylinder. At the same time, the grease in the cylinder above the piston is displaced upwardly under pressure through the cylinder toward the delivery fitting. During the downward or transfer stroke, the grease, which is trapped between the ball 25 and piston 16, in forced upwardly through the ball check valve 27 of the piston to the space above it for displacement under pressure during the next charging and delivery stroke. The piston ball check valve 27 cooperates with a seat formed in the piston, the ball being forced against the seat by the compression spring 28. Lateral passageways 30, which are formed in the piston, allow the grease to flow from valve 27 through the piston to the cylinder.

In the present structure, the barrel 8 constitutcs a reservoir or accumulator for confining a mass of grease under pressure for delivery through the conduit 14 to the discharge nozzle. For this purpose, there is provided a. spring loaded piston (not shown) in the upper portion of the barrel which is sealed with respect to the barrel and the external surface of cylinder 15. A coil spring 31 is seated under compression between the lower end 32 of the barrel and the piston to urge the piston upwardly. The upper portion of cylinder 15 includes a delivery passageway (not shown) open to the upper end of barrel S and communicating With the space above the reservoir piston. A grease delivery passageway also extends from the upper end of the barrel to the delivery fitting 13 and conduit 14. Accordingly, reciprocation of the pump piston feeds grease under pressure into the reservoir to force the reservoir piston downwardly. This compresses spring 31, such that a supply of grease is maintained under pressure -in the reservoir for discharge through the conduit 14 to the delivery nozzle.

As .shown in Figure l, the grease pump assembly is attached to the cover plate by the nut 33 which is threaded upon -the upper end of barrel 8. The upper end of the pump cylinder, which 'projeots above the `cover plate, in-

cludes a packing gland housing 34 for the upper portion of the piston rod 17; the housing also includes the grease passageway, previously noted, which extends from the barrel and pump cylinder to the delivery fitting 13. The packing gland housing includes a hexagonal portion 35 which seats upon the upper surface of plate 24, the assembly being clamped rigidly by the nut 33 which engages the lower surface of the cover plate 10.

The upper end of the grease drum is curled over as at 36 and.the cover plate includes a fiange 37 overhanging the curled portion of the drum. Clarnping screws 38 are threaded through the fiange 37 of the cover plate and engage beneath the curled portion to clamp the cover plate and pump upon the drum. When the drum is empty, the clamping screws 38 are screwed outwardly to disengage the curl; the pump assembly, including the follow plate, may then be removed as a unit and replaced upon a fresh drum.

In order to accommodate the dispensing pump to drums having different depths, an extensible tube 40 is telescopically mounted upon the lower portion of the pump cylinder 15. The lower end of the tube is provided with intake ports 41 which normally reside adjacent the bottom plate 42 of the drum. In order to prevent leakage of air between the tube 40 and cylinder 15, a sliding seal is interposed between the sleeve and cylinder. The seal may be provided by a conventional rubber seal ring encircling the cylinder and confined in an annular bead 43 formed around the tube and delineating a groove to confine the seal ring.

In the present pump structure, the upper end of the sleeve 11 contacts the lower surface of nut 33 and is compressed lengthwise when the pump is mounted upon a full drum of grease as shown in Figure 1. As explained earlier, this causes the sleeve to become corrugated or buckled annularly as indicated at 44. If the sleeve were rigid lengthwise instead of collapsible, then it would not be possible to place the follow plate in a full drum of grease; in other words, the sleeve would project upwardly above the top of the drum and interfere with the cover and top of the pump. It would then be necessary either to force the follow plate downwardly to displace the excess grease from the drum or to remove a substantial amount of grease before installing the follow plate. It Will be understood that the corrugated sleeve establishes a seal with the pump barrel and that the seal is maintained after the sleeve straightens to its cylindrical condition.

in order to control the shape of the compressed sleeve, the wall of the sleeve may be preformed to provide partial corrugations; however, experimental work has indicated that a plain cylindrical sleeve, with no corrugations, is capable of being compressed endwisely in generally the same manner. In other words, the pump barrel 8 forms a rigid backing which prevents the folds of corrugations from buckling or distorting excessively. It will be understood from the foregoing, that when applied to pumps which do not utilize the barrel S, a flexible sleeve is utiiized which has a diameter suitable to fit slidably upon the pump cylinder, the follow plate having a central opening of corresponding size.

In its preferred form, the body of the follow plate consists of a pair of spaced relatively thin discs 45-45 which may be formed from sheet metal such as aluminum, or from non-metallic material, such as sheet plastic, plywood or the like. As detailed in Figure 4, the sealing strip 12 has a marginal portion L-6 which is clamped between the marginal edges of the discs 45 and stitched permanently in position by the Wire staples 47. The staples may be applied by a conventional stapling machine, the discs either being pre-punched to receive them, or if the material is suitable, the staples may be driven through the sheet material. The lower ends of the staples are clinched over upon the surface of the lower disc in the usual manner.

The sealing sleeve 11 is attached to the spaced disc in the same manner as the sealing strip 12. For this pufpose the sleeve includes a fiange 48 (Figure 4) at its lower end which is clamped between the discs surrounding the central opening 50. The flange 50 is secured permanently in position by a series of radially disposed staples 47, similar to the sealing strip 12.

The shipping drum 6 for which the follow plate structure is particularly intended, is fabricated from sheet metal and frequently is forced slightly out of round or dented during shipment and handling. Moreover, many drums are over size or under size, normally making it necessary to provide a substantial clearance around the follow plate. The flexible sealing strip 12, as best shown in Fig. 4, normally extends outwardly a substantial distance beyond the edge of the rigid discs 45 and is sprung upwardly as the follow plate moves downwardly into the drum. The unsupported portion of the strip thus becomes cupped and accommodates the follow plate to drums with variations in diameter. The cupped portion of the strip is acted upon by atmospheric pressure in a direction to urge the edge of the strip into engagement with the wall of the drum. The expansion of the strip against the wall of the container provides a lineal seal to prevent the leakage of air and also provides an effective wiping action to prevent grease from adhering to the drum surface. Moreover, the free portion of the strip is readily deformable upon encountering any irregularity in the wall surface of the drum. The flexible sleeve 11 likewise is forced under atmospheric pressure into contact with the surface of the barrel 8 to provide a selfsealing interface.

The present follow plate structure is intended to be furnished both as a replacement unit for existing dispensing pumps and as a component part of new pump assemblies. When the pump is to be installed upon a drum of lubricant, the follow plate preferably is shifted by a hand toward the upper portion of the pump barrel or cylinder as the case may be. For this purpose a handle 51 is attached to the upper disc, preferably by welding as at 52, if the disc is formed of sheet metal. If the discs are constructed of nonmetallic material, the handle may be attached by staples or by other appropriate fastening means.

When the pump is placed in the drum, the follow plate rests upon the surface of the grease and the sleeve adjusts itself automatically to the grease level. As the grease is pumped out, the sleeve assumes its cylindrical shape, and in conjunction with the sealing strip 12, seals off the mass of grease until the follow plate reaches the bottom of the drum. In the event that pumping is continued after the drum is empty, atmospheric pressure acting upon the unsupported portion of the sleeve, may collapse the sleeve inwardly toward the extensible tube 40 as indicated at 53. Normally however, pumping is stopped before actual collapse occurs. In either event, the vacuum may be relieved by pulling upwardly upon handle 51 so as to tilt the follow plate. This breaks the Seal between strip 12 and the drum surface and allows the follow plate and pump to be removed.

From the foregoing, it will be understood that the follow plate structure compensates for the level of the grease in the drum at the start of a pumping operation and allows the grease to be pumped without interruption from the drum until it is completely empty. During pumping, the sealing action of the structure is effective to prevent channeling of air through the grease and thus improves the efficiency of the pump. The cupping of the sealing strip 12 allows the follow plate to maintain the seal in spite of differences in drum diameter or irregularities in the surface of the drum. It will also be noted that the sealing strip and sleeve operate in the presence of lubricant which adheres to the surface of the barrel and drum. This reduced frictional resistance and produces an effective seal without requiring a great deal of sealing pressure. For this reason, the sleeve may fit rather loosely around the barrel or cylinder to promote free sliding action as the follow plate descends.

Having described my invention I claim:

l. A follow plate for a lubricant dispensing pump of the type adapted to be mounted upon the top of a lubricant container and having a pump cylinder including an intake passageway to withdraw the lubricant by suction from the lower portion of the container, the follow plate adapted to provide a seal relative to the lubricant in the container below the follow plate and to maintain said seal as the follow plate moves to the bottorn of the container, said follow plate comprising, a follow plate disc formed of relatively rigid Sheet material, said disc having a central opening to slidably receive the pump cylinder, a sealing strip attached to the peripheral portion of the follow plate disc to provide a seal relative to the internal surface of the container, and a generally cylindrical sealing sleeve formed of relatively thin flexible material, the sleeve projecting upwardly from the plane of the disc and having its lower end attached to the disc, the sleeve being concentric to the said central opening to encircle the pump cylinder, the thin flexible sleeve being compressible circumferentially into contact with the periphery of the pump cylinder in response to atmosphere pressure and providing an air seal around the cylinder above the follow plate, the sealing sleeve having a substantial length and being collapsible lengthwise between the pump and follow plate to compensate for the lubricant level when the pump and follow plate are niounted upon the container, the sleeve being expensible to full length in response to downward motion of the follow plate toward the bottom of the container to provide a seal above the intake passageway as the follow plate moves downwardly in the container.

2. A follow plate for a lubricant pump of the type adapted to be mounted upon the top of a lubricant container and having a pump cylinder including an intake passageway to withdraw lubricant by suction from the lower portion of the container, the follow plate adapted to provide a seal relative to the lubricant in the container below the follow plate and to maintain said seal as the follow plate moves to the bottorn of the container, said follow plate coniprising, a follow plate disc formed of relatively rigid material, said disc having a central opening to slidably receive the pump cylinder, a sealing strip formed of relatively thin ilexible material attached to the peripheral portion of the follow plate disc, said strip having a free portion projecting outwardly beyond the periphery of the disc, said sealing strip being cupped upwardly from the follow plate with its periphery engaging the internal surface of the container, the thin fiexible sealing strip being expansible outwardly toward the internal surface of the container in response to atmospheric pressure to provide a llexible seal relative to the internal surface of the container, and a generally cylindrical sealing sleeve formed of relativcly thin flexible materiah, the sleeve projecting upwardly from the plane of the disc and having its lower end attached to the disc, the sleeve being concentric to the central opening to embrace the pump cylinder, the thin ilexible sleeve being compressible circumferentially into contact with the periphery of the pump cylinder in response to atmospheric pressure and providing an air seal around the cylinder above the follow plate, the sealing sleeve having a substantial length and being collapsible lengthwise in accordion fashion between the pump and follow plate to compensate for the lubricant level when the pump and follow plate are mounted upon the container, the sleeve being expansible to full length in response to downward motion of the follow plate toward the bottom of the container, whereby the sleeve provides a seal above the intake passageway as the follow plate moves downwardly in the container.

3. A follow plate for a lubricant dispensing pump of the type having an upper end adapted to be mounted upon a lubricant container and having a pump cylinder including an intalre passageway to Withdraw lubricant by suction from the lower portion of the container, the follow plate adapted to provide a seal relative to the lubricant in the container below the follow plate and to maintain said seal as the follow plate moves to the bottom of the container, said follow plate comprising, a pair of spaced follow plate discs formed of sheet material, said discs having a central opening to receive the pump cylinder, a sealing strip interposed between said spaced discs and extending around the periphery thereof, the diameter of said follow plate discs being less than the internal diameter of the container, the edge portion of the sealing strip extendin g outwardly from the edge of the discs and being cupped upwardly from said follow plate discs, the thin fiexible sealing strip being expansible outwardly into contact with the internal surface of the container in response to atmospheric pressure to provide a seal relative to the internal surface of the container, a generally cylindn'cal sealing sleeve formed of relatively thin ilexible material, said sleeve projccting upwardly from the plane of the discs and having a lower portion interposed between the spaced discs extending around the periphery of the central opening thereof, and means engaging said discs and clamping said seaiing strip and lower portion of the sleeve therebetween, the sealing sleeve having a substantial length, the thin flexible sleeve being compressible circumferentially into contact with the periphery of the pump cylinder in response to atmospheric pressure and providing an air seal around the cylinder above the follow plate, the sleeve being collapsible lengthwise between the pump and follow plate when the lubricant level is adiacent the upper end of the container and being expansiblc to full length in response to the downward motion of the follow plate to provide a seal above the said intake pasageway as the follow plate moves downwardly in the container.

4. A follow plate for a lubricant dispensing pump of the type adapted to be mounted upon a lubricant container and having a pump cylinder including an intake passageway to withdraw lubricant by auction from the lower portion of the container, the follow plate adapted to provide a seal relative to the lubricant in the container below the follow plate and to maintain said seal as the follow plate moves to the bottorn of the container, said follow plate compn'sing, a pair of spaced follow plate discs formed of relatively rigid sheet material, said discs having a central opening to receive the pump cylinder, a sealing strip formed of relatively thin flexible material, said sealing strip having an inner edge portion interposed between and extending around the periphery of said discs, means engaging the discs and clarnping the inner edge portion therebetween, said strip having a peripheral edge portion extendin g outwardly beyond the periphery of the discs to provide a sealvrelative to the internal surface of the container, a generally cylindrical sealing sleeve formed of rclatively thin exible material, said sleeve proviecting upwardly from the plane of the discs and having a flange at the lower end thereof interposed between the spaced discs and extending around the periphcry of the central opening thereof, and means engaging said discs and clamping the said fiange therebetwecn, the scaling sleeve having a substantial length, the thin fiexible sleeve being compressible circumferentially into contact with the periphery of the pump cylinder in response to atmospheric pressure and providing an air seal around the cylinder above the follow plate, the sleeve being collapsible lengthwise between the pump and follow plate when the lubricant level is adjacent the upper end of the container and being cxpansible to full length in response to the downward motion of the followy plate to provide a seal above the said intake passageway as the follow plate inoves downwardly in the container.

References Cited in the file of this patent UNITED STATES PATENTS 205,120 Moreau lune 18, 1878 l,7l4,254 Zerk May 21, 1929 l,931,12l Zerk Oct. 17, 1933 2,627,814 Davis Feb. 10, 1953

Claims

4. A FOLLOW PLATE FOR A LUBRICANT DISPENSING PUMP OF THE TYPE ADAPTED TO BE MOUNTED UPON A LUBRICANT CONTAINER AND HAVING A PUMP CYLINDER INCLUDING AN INTAKE PASSAGEWAY TO WITHDRAW LUBRICANT BY SUCTION FROM THE LOWER PORTION OF THE CONTAINER, THE FOLLOW PLATE ADAPTED TO PROVIDE A SEAL RELATIVE TO THE LUBRICANT IN THE CONTAINER BELOW THE FOLLOW PLATE AND TO MAINTAIN SAID SEAL AS THE FOLLOW PLATE MOVES TO THE BOTTOM OF THE CONTAINER, SAID FOLLOW PLATE COMPRISING, A PAIR OF SPACED FOLLOW PLATE DISCS FORMED OF RELATIVELY RIGID SHEET MATERIAL, SAID DISCS HAVING A CENTRAL OPENING TO RECEIVE THE PUMP CYLINDER, A SEALING STRIP FORMED OF RELATIVELY THIN FLEXIBLE MATERIAL, SAID SEALING STRIP HAVING AN INNER EDGE PORTION INTERPOSED BETWEEN AND EXTENDING AROUND THE PERIPHERY OF SAID DISCS, MEANS ENGAGING THE DISCS AND CLAMPING THE INNER EDGE PORTION THEREBETWEEN, SAID STRIP HAVING A PERIPHERAL EDGE PORTION EXTENDING OUTWARDLY BEYOND THE PERIPHERY OF THE DISCS TO PROVIDE A SEAL RELATIVE TO THE INTERNAL SURFACE OF THE CONTAINER, A GENERALLY CYLINDRICAL SEALING SLEEVE FORMED OF RELATIVELY THIN FLEXIBLE MATERIAL, SAID SLEEVE PROJECTING UPWARDLY FROM THE PLANE OF THE DISCS AND HAVING A FLANGE