US2978151A - Multi-fill grease gun - Google Patents

Description

April 4, 1961 E. P. SUNDHOLM 2,973,151

MULTI-FILL GREASE GUN Filed July 1, 1957 I I I, 20 ,4

/N VE N TOR United States Patent 6 2,91 5 R ASE Edwin P. Sundhohn, Albert City, Iowa Filed July 1, 1957, Ser. No. 669,230 (C 22-38 5 This invention relates to a multi-fill grease application is a continuation-in-part of my'eopending application, Serial No. 636,971, filed January 2 9 19, 57, now Patent No. 2,915,226. dated Deeember- 1, 19,59,

\ There are at least three common methods of filling grease guns. In the pressure fill method, bulk grease-is pumped into the barrel of the grease gun through opening in the dispensinghead. Alternatively, the grease may be sucked into the grease gun. barrel. with the (lis pensing head removed. Still another method is that of inserting the grease in the form of a pre-paekaged cartrid'ge. From the standpoint of flexibility andrversatility This invention is shown in illustrative embodiments in i the accompanying drawings, in whi ch-- Figurel is a side sectional view of agrease gun embodying the general principles of the present invention; Figure 2., is an enlarged sectional detailview of the, dispensing head of the grease gun of. Figure 1, taken on line 2-2- of Figure 1; Figure 3, a fragmentaryside sectional View of a preferred-"modification of the grease gun. in Figure 1; and Figure 4, is another fragmentary side sectional view showing another. preferred modification, of the grease gun in Figure l. 7

Looking first at the embodiment of Figures hand 2, there is shown a grease gun. which includesthe usual cylindrical grease container 10 having a dispensing. head 11 detachably mounted on the forward end; thereof. The rear of the gun is. provided with a closure cap 12 which is threadedly connected to. container 10, Within container 10 is a slidable' plunger assembly 14 having; a cup-shaped piston. or head: portion 15 arranged for urging grease toward dispensing head 11. In the illustration given, a compression spring 16 is disposed between the back of plunger assembly 14 and rear cap 12. If desired, however; the spring can beomitted.

In the embodiment of Figures 1 and,- 2, a ferrule or sleeve 17 of slightly smaller diameter than the internal diameter of container 10' is disposed in the rearward portion of the container. The open forward end of sleeve 17 is preferably arrangedv substantiallyconcentrically with the bore of cylinder 10. Means are also provided for retracting plunger assembly 14 and more particularly head portion 15 thereof into the forward end of sleeve:1 7,- which in the illustration given includes a plunger rod 18 extending from plunger head portion. 14 through the rear wall'of cap 12.

2,978,151 ,Patent d An 1 1 as illustrated in Figures. '1 and 2, the sidewall portions beingdesignated by the number 15a. It will be noted that the. side walls 151: of the piston terminate. in an annular portion 15b which engages the inner walls of container 10 as indicated in Figure l. Preferably, the outer surface of the piston side wall is substantially smooth and the inner surface thereof is provided. with an inwardly-extending ridge, as indicated by the reference numeral 150. Ridge portion 15c is substantially opposite the container wall engagi g-Portion of the .outer surface of. the piston side wall 15a. It will be understood that the outermost portion of the piston side walls will have a. slightly greater exterior diameter; than.- the interior diameter of containerv 10 to maintain the desired sealing relationship between these contacting surfaces. Also, the. inwardrnost portion of piston side walls 15a shouldhave an exterior diameterv such that the piston 15 can be withdrawnand compressed within sleeve 17 upon the. exertion of sufficient force. thereon,

Plunger head assembly 15 may take variousv forms while. still achieving the benefits of the present invention. In the illustrations given in Figures 1 and 2, the transverse body portion of piston 15 is clamped between front washer 19 and rear washer 20, these. members being interlocked to prevent any lateral shifting, of piston 15. Inthe illustration given, a headed plug zl extends-through the unites washers 19 and 20 and the body portion of piston. 15; For the purpose of permitting, plunger rod 18 to, move downwardly into container 10 independently of the downward movement of plunger head assembly 14, the head portion of plug. 21 is provided with a T- shaped slot 22, and the. outer end of rod 1.8is' provided with a laterally extending. pin 23.. Since this means of releasably attaching a plunger assembly to a rod "is old and well=known in grease guns, it is not believed that it be necessary to further describe it herein. a

For convenience of assembly and operation, as shown in: the specific embodiments in Figures 1 and 2, rear cap 12 can be formed to provide a rearwardly extending tubular portion 121:- of substantially the same internal diameter. as. the external diameter of sleeve 17, thereby permitting the rearward portion of the sleeve to be receivedwithin the. tubular portion of the cap. in tight frictional engagement therewith. The mounting of sleeve 17 within the tubular portion 12a by means of a press fit serves the purpose of holding sleeve -17 in fixed, concentric relation to container 10, while providinganannular space 24 between the outside of the forward portion of sleeve 17 and. the inside of the rearward portion of container 10. In the illustration. given, cap 12 also provides a skirt portion 1212, the skirt portion being forwardly of the tubular portion 12a for being. threadedly received over the outside of the rear end portion of container. 10. Cap 12 also preferably provides an inwardly extending shoulder portion so that a sealing gasket 25'can. be clamped between the inner wall of the cap shoulder portion at the rear end. of container 10 to seal off the threaded connection from; the interior of container 10. If desired, however, sealingagasket. 25 can be omitted for reasons which will subsequently be explained.

For the purpose of the present invention, the construction of the dispensing'head is of no particular importance providing the head is detachable from the grease container and that it provides an inlet for pumping grease into the container through the head. For example, dispensing head 11, shown in Figures 1 and 2, includes a body 26 having a bore 27 therein for slidably receiving a piston plunger 28 that extends outwardly beyond body- '26 and is pivotally connected to a lever arm 29. The

forward end of lever 29 is pivotally connected to a pair of links 30, which in turnare pivotally mounted on body '26, thereby permitting piston 28 to be reciprocated by the corresponding reciprocation of lever 29. The bore 27 communicates with an inlet opening 31 which extends through cap portion 32 and the adjacent wall of body 26 26 also provides an opening 33 communicating with the end of bore 27 towards which piston rod 28 advances.

A grease discharge fitting 34 is threadedly received with- 'in opening 33 provides a passage for the outflow of grease, and includes a spring-biased check valve 35 which is arranged to permit outflow only. The outer end of gating 34 is adapted to receive a grease applicator pipe As shown more clearly in Figure 2, the transverse wall of cap 32 is provided with an inlet opening 37, which in the illustration given, is internally threaded to receive a filler fitting 38 and thereby mount the same on the outside of head 11 to provide a passage extending from the outside to the inside of container 10. Preferably, fitting 38 includes a spring-urged check valve 39 arranged to permit only inflow.

In one method of filling the grease gun of Figures 1 and 2, grease is pumped into container 10 through fitting 38. In this operation, as the grease is forced in under pressure plunger assembly 14 will be driven rearwardly. The pumping is preferably continued until the plunger assembly 14 reaches approximately the position illustrated in Figure 1, where the rear end of piston has just begun to enter the mouth of sleeve 17. At this point, 'there will be increased resistance to the further rearward movement of the plunger, and this will require greater exertion of effort by the person operating the filling pump. This can be used as a signal to the operator to discontinue the pumping. Further pumping would have the result of forcing the plunger head within sleeve 17, thereby separating the piston 15 from the inner walls of container 10, and permitting grease to flow into the annular space 24.

In the filling operation just described, sleeve 17 has the function of restricting the rearward movement of piston 15. The sleeve 17 would also serve this purpose in connection with a suction filling operation wherein dispensing head 11 was removed, and grease was being sucked into container 10 by drawing plunger assembly 14 toward the rear by means of plunger rod 18. Whenever it is desired to insert a grease cartridge within container 10, however, this can readily be done by exerting sufiicient force on plunger 14 to withdraw it within sleeve 17. Upon the introduction of the grease cartridge, the piston 15 will then be automatically inserted within the open rear end of the grease cartridge, as described more fully in my co-pending application Serial No.

636,971, filed January 29, 1957.

of the cup-shape piston to restrict further rearward movement of the piston while maintaining the engagement between the piston and the inner walls of the container.

In the modified constructions of Figures 3 and 4 the parts corresponding to those of the construction of Figures -1 and 2 have been given the same numbers except that the numbers in Figure 3 have been primed and in Figure v4 double primed to indicate that they are applied to modifications. It will be noted that in the constructions of both Figures 3 and the cup-shaped pistons 15' and side walls 15a and 15a and positively stop any further piston side walls 4 15" have been reversed so that the outwardly flarin sides 15a and 15a" extend toward the rear of the gun. In the Figure 3 modification, sleeve 17 has been shortened so that the annular space or pocket 24 is adapted to just receive the outermost portion of piston side walls 15a. As shown in Figure 3, this arrangement provides a positive stop for the rearward movement of the plunger assembly 14.

Similarly, in the construction of Figure 4, the sleeve or ring 17" is arranged to provide a pocket 24" for receiving the outer extremity of piston side walls 15a". Ring 17", as shown in Figure 4, has an angular cross section so that it can be clamped between rear cap shoulder 12c" and sealing gasket 25", the forwardlyextending portion of sleeve 17" being inclined inwardly to correspond with the taper of the inner lip portion of piston side walls 15a". The way in which this arrangement acts as a positive stop for the rearward movement of plunger assembly 14" is illustrated in Figure 4.

In using grease guns employing constructions like that illustrated in Figures 3 and 4, grease can be pumped into the grease containers in the usual way, and the pumping continued without any particular concern as to whether grease will be forced between the side walls of the piston and the grease container, which if it occurred would allow the grease to pass behind the plunger assembly, covering the spring and other parts with grease, and even permitting grease to escape through the rear cap. The annular pockets 24' and 24", as indicated above,.will receive the outermost portion of the piston rearward movement of the plunger assemblies 14' and 14". When this occurs the further introduction of grease can be discontinued, and even if an attempt is made to pump in additional amounts of grease, the seal between 'the pistons 15' or 15" and the inner walls of. containers 10 and 10" will be maintained. The sleeves 17' and 17" are arranged to provide and maintain the desired sealing relationship. As an added precaution, the annular pockets 24 and 24" are dimensioned so that the tip end of the 15a and 15a" can come into sealing engagement with the gaskets 25' and 25" which are positioned respectively at the bottoms of pockets 24' and 25".

The modifications of Figures 3 and 4 can also be used where it is desired to fill grease guns with cartridge packaged greases. By employing pistons which have outwardly flaring side walls extending toward the rear of the guns, the pistons are self-inserting with respect to the grease cartridges. Also, grease can be sucked into guns constructed like those shown in Figures 3 and 4. In fact, the reversing of the pistons will provide an increased suction effect, and will therefore improve the suction filling action of such guns.

While in the foregoing specification this invention has been described with reference to specific embodiments thereof and many details have been set forth with respect to these embodiments, it will be understood by those skilled in the art that the invention is susceptible to other embodiments and that many of the specific details described herein can be varied considerably without departing from the basic concepts and principles of the invention.

I claim:

1. In a grease gun adapted for both pressure and suction filling and including a cylindrical grease container "having front and rear ends, a dispensing head removably mounted on the front of said container, said dispensing head providing an inlet opening through which grease can be pumped into the frontward portion of said container, and a slidable plunger assembly within said container "arranged for movement away from and towards said aeralei the inner walls of said container, all other componentsof said plunger assembly being spaced inwardly from the said inner walls of said container, and annular positive stop means disposed within the rearward portion of said container in the path of rearward movement of said outwardmost portion of said piston side walls, said stop means cooperating with said outwardmost side wall portion of said piston to restrict further rearward movement of said piston while maintaining the engagement between said annular portion and the inner walls of said container.

2.. In a grease gun adapted for both pressure and suction filling including a cylindrical grease container having front and rear ends, a dispensing head removably mounted on the front end of said container, said dispensing head providing an inlet opening through which grease can be pumped into the frontward portion of said container, a slidable plunger assembly within said container arranged for movement away from and toward said dispensing head, said plunger assembly comprising a cup-shaped piston of flexible, resilient material arranged in concentric relation to the inner walls of said container, said piston having outwardly flaring side walls extending toward the rear end of said container and terminating in an annular portion in engagement with the inner walls of said container, all other components of said plunger assembly being spaced inwardly from the said inner walls of said container, and means disposed within the rearward portion of said container cooperating with the said outwardly flaring side walls of said piston to restrict further rearward movement of said piston while maintaining the engagement between said annular portion and the inner walls of said container. 7

3-. The combination of claim 2 wherein said restricting means comprises a ring mounted in the rearward portion of said container, said ring having a frontward end portion spaced inwardly from the inner walls of said container to provide an annular pocket therebetween for receiving the outermost portion of said flared piston side walls.

References Cited in the file of this patent UNITED STATES PATENTS

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