US2797029A - Grease gun - Google Patents

Description

B. A. BEAVER GREASE GUN June 25, 1957 5 Sheets-Sheet 1 Filed March 23. 1950 B. A. BEAVER GREASE GUN June 25, 1957 5 Sheets-Sheet 2 Filed March 25, 1950 INVENTOR 305:} fieazr 5 v (AHORNEY June 25, 1957 B. A. BEAVER GREASE GUN 5 Sheets-Sheet 3 Filed March 23. 1950 INVENTOR Basil fieazfer ATTORNEY vuusus Q QM QM VQN w@ v Y MN m l||\ June 25, 1957 B. A. BEAVER GREASE GUN Filed March 23, 1950 5 Sheets-Sheet 4 I a L 1 HJV l .HH A V W V III I II I MN @k June 25, 1957 B. A. BEAVER GREASE GUN 5 Sheets-Sheet 5 Filed March 23. 1950 Cikkfiiif n Q 5% United States Patent C) GREASE GUN Basil A. Beaver, Minneapolis, Minn.

Application March 23, 1950, Serial No. 151,485

8 Claims. (Cl. 222-468) The present invention relates to grease guns or the like and it relates more particularly to a new and improved construction for portable hand-operated guns for delivering lubricant under pressure from a self-contained refillable reservoir to a bearing or the like requiring lubrication.

An object of the present invention is to provide a new and improved construction for grease guns or the like.

Another object of the present invention is to provide a grease gun wherein the barrel or cylinder is formed by impact-extrusion whereby an apertured end-wall can be formed integrally therewith and whereby external rein-.

forcing ribs can be formed in the same operation.

Still another object of the present invention is to provide a grease gun wherein an impact-extruded barrel of the type mentioned above can be combined with other features of construction and operation to give more effective operation in suction type push-pull grease guns and in grease guns having a low pressure push-pull pump as well as a high pressure lever-operated pump, and in grease guns having a push-pull pump combining a spring-actuated low pressure element and a manually operated high pressure element.

Other objects and advantages of the present invention are apparent in the following detailed description, appended claims and accompanying drawings.

For the purpose of illustrating the invention, there are shown in the accompanying drawings forms thereof which are at present preferred, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and that the invention is not limited to the precise arrangements and organizations of the instrumentalities as herein shown and described.

Referring to the accompanying drawings in which like reference characters indicate like parts throughout:

Figure l is a longitudinal section through the barrel, the section being approximately on line 1-1 of Figure .2.

Figure 2 is an end elevation of the barrel of Figure 1.

Figure 3 is a side elevation of the barrel with :the nozzle end shown in section.

Figure 4 is a perspective view with the nozzle end shown separated. 1

Figure 5 represents a view in longitudinal section showing the barrel and nozzle of Figure 3 employed in conjunction with a push-pull low pressure piston.

Figure 6 is an end elevation, on a somewhat enlarged scale, of the piston of FigureS.

Figure 7 is a cross-sectionalview taken .generally along the line of 77 of Figure 6.

Figure 8 is a side elevation showing the nozzle disconnected from the barrel and showing the operating handle in dotted lines.

Figure 9 is a longitudinal section through another highpressure embodiment of the present invention.

Figure 10 represents a perspective view showing the front end of the barrel of Figure 9.

Figure .11 represents a fragmentary sectional view showing the front end of a low-pressure embodiment similar to that shown in Figure 9.

Figure 12 represents an enlarged fragmentary sectional view of the piston and rear end of the embodiment of Figure 9, showing particularly thepiston-locking' mechamsm.

Figure 13 is a cross-sectional view generally similarto that of Figure '9 showing a modified embodiment.

Figure 14 represents a side elevational view of the embodiment of Figure 13 (which is similar in this respect to the embodiment of Figure 9). V g

Figure 15 represents a longitudinal cross-sectional view of a lever-type. grease-gun constituting another embodiment of the present invention. 1

Figure 16 represents a fragmentary cross-sectionalview on an enlarged scale, showing the front or high-pressure piston end of the grease-gun of Figure 15.

Referring particularly to Figures 1 to 4 inclusive of the drawings, the barrel 10 is generally cylindrical and is made from aluminum, or aluminum alloy, by an impactextrusion process. The barrel has a nearly closed, integral rear end 32 and a plurality of parallel, longitudinal ribs 38 projecting from the exterior of the barrel, with smooth areas 37 between the ribs. These ribs greatly strengthen the barrel and permit the use of a barrel with comparatively thin walls, and at the same time they permit the barrel to be gripped securely, even by greasy hands.

The nearly closed integral rear end 32 also greatly-strengthens that end of the barrel. An axial bore 33 (-in the integral rear end 32) receives the piston-rod (129 or 202 or 301) which has a handle (135') on the outer end thereof for retracting a piston (119 or 201) to suck up lubricant through the nozzle 11 of the grease-gun or suction gun. The front end of the barrel 10 has external screw-threads 12 for threaded engagement with the cap 11, which cap has complementary internal screw-threads 18, for similar engagement with the barrel. Cap member 11 is preferably an aluminum or aluminum alloy casting and may have a screw-threaded axial bore 13 located at its forward end adapted to make a connection with a hose or coupling :member (not shown) through which -lubricant may be sucked up into the gun or discharged therefrom.

Referring now particularly to Figures '5 to 8, inclu- :sive, .a piston 119 is s'lidably mounted in the cylindrical interior of the barrel 10 and is provided with an annu- 'lar ring-receiving groove 120 in which an 0 type sealingring 121 is mounted. This sealing-ring 121 may be of .rubber or synthetic rubber or similar material which is capable of forming .a fluid-tight :seal between the piston 119 and the barrel 10, and which :is resistant to grease and oil or the like. "The sealing-ring 121 may be ci rcular in cross-section and preferably has a diameter some what less than the axial width of the ring-receiving groove 120, so that it is free-floating? or movable backward and forward as the piston is reciprocated within-the barrel. Theradial depth of the ring-receiving groove 120 is slightly less than-the radial dimension of the crosssection of the sealing-ring 121, so that the ring is compressed radially, slightly, betweenithe' barrel wall andthe bottom of the groove 120, toprovide a fluid-tight seal. The piston 119, which may be an aluminum or alloy casting, is generally cup-shaped iand' has a counterbore 122 in the forward end thereof. A steel Washer1'23 rests on the shoulder 124, and is held thereagainst by the flange 125 which has been peened, rolled or spun over the edge of the washer 123. An elongated slot 126 is cut in the washer 123 and has radially-extending portions 127 and 128. A piston-rod 129 is slidably mounted in the bore 33 of the barrel 1t), and passes through a -central bore 130 in the piston and through the slot 126.1in the washer 123. .A transverse pin 131, extending radially from the end of the piston-rod 129, is adapted-to pass through the slot 127, or :the slot 128, and, after-being turned 'angularly about the axis of the piston-rod 129, to ;.lock the piston-rod 1110 the piston assembly when the pin Patented June 25, 1957 or conduit into the can or other point of discharge.

.131 is disposed within the counterbore 122behind the washer 123. The bore 130 may have a recess or groove 132 therein, and an type packing ring, sealing ring or gasket 133 is placed in the groove 132 around the piston- .as at, 134, and a handle, 135, preferably -.a pistol-grip handle, is screw-threaded thereon. made of an aluminum or alloy casting.

When it is desired to remove some used lubricant from the crank-case, differential or other relatively inaccessible part of a motor vehicle, a hose or other conduit, which as stated above may be coupled to cap 11,"is dipped into the breather-pipe of the crank-case, or the other means of access, so that the outer end of the hose or conduit is immersed in the used lubricant. During this step the pistonis in its forward position, as shown in Figure 5. Handle 135 is then pulled backward, with respect to the barrel 10, carrying with it piston 119 and creating a vacuum in the interior of the barrel, thus drawing the used or spent lubricant up into the barrel. When the used lubricant has been completely removed or when the barrel is practically full, the suction-gun is withdrawn, hose and all, and carried to a waste can, drain or other place of disposal. Handle 135 is then pushed in so that the lubricant in the barrel isexpelled through the hose The operation is repeated as many times as is necessary to remove all used or waste lubricant. Then the crankcase or other part is refilled with fresh lubricant in the usual manner.

Referring now particularly to the embodiment of Figures 9 to 12, inclusive, a piston 201 is reciprocably mounted within the barrel 10a and a piston-rod 202 is connected to the piston in a manner to be presently explained. The piston-rod 202 extends through the bore 33-a without contact therewith (the bore being larger in diameter than the piston-rod and having a guidesleeve 263 interposed therewithin, as will be presently explained). The outer end of piston-rod 202 has screwthreads 203 and has a pistol-grip type handle 135 secured thereto by said threads.

The barrel 10a in this embodiment generally resembles the barrel 10 heretofore described.

In place of the external screw-threads 12 at the forward open end, the barrel 10-a is provided with rela-v tively coarse external threads 208 formed at the rear end of the front cylinder-bearing cap member 209. The ring or collar 205 serves to connect the cap member '209 to Handle 135 may be the barrel 1041. Because of the diiference in frictional resistance offered by the fine and coarse threads on the ring 205, the cap member 209 may be unscrewed without .loosening the connection between the ring 205 and the barrel 10-a.

A number (for example 4) of integrally-formed external ribs 210 may be provided on the cap member 209 as indicated particularly in Figure 14. The ribs 210 facilitate unscrewing of the cap member 209.

A gasket 211 is interposed between the ring 205 and the cap member 209 to seal the joint therebetween. The rear end of the ring 205 provides an annular shoulder or abutment to stop forward motion of piston 201 as shown in Figure 9.

The cap member 209 has an axial bore 212 therein, terminating in a larger counter-bore 213 which has internal threads 214 at the inner end thereof. A sleevelike pump-cylinder member 215 is mounted within the counter-bore 213 and the bore 212, as shown in Figure 9;

said pump-cylinder 215 having an internal bore 216 serving as a pump-cylinder, and a counter-bore 217 therewithin serving as a check-valve housing. The pumpcylinder member 215 is preferably made of steel or other metal suitable for a pump-cylinder and is machined to a suitably close tolerance in relation to the piston 223. A ball check valve 218, held against the seat 219 in the counter-bore 217 by a compression spring 220, prevents lubricant from being discharged from the gun except when the delivery pressure is above that of the spring pressure, and enables the formation of suction in the cylinder-bore 216 when the piston 223 is retracted.

The pressure of spring 220 is maintained by a screwthreaded sleeve 221 which is threaded into the threaded counter-bore 217. The sleeve 221 is provided with an enlarged external head portion 222 which may be externally screw-threaded or internally screw-threaded or otherwise constructed and arranged for detachable connection to a delivery hose or pipe having a coupler or nozzle on its free end (not shown)v for connection or contact with the fitting or other part to be lubricated.

The cap member 209 (Figure 11) may be adapted to receive a pump-piston 290 of somewhat larger diameter than the pump-piston 223 in Figure 9, by eliminating pump-cylinder portion 224 of the sleeve-member 215. Thus, only that forward portion of the sleeve-member 215 which is disposed within and engages the threads 214 in the counter-bore 213 and serves as a housing for the ball check valve 218, is used in the embodiment shown in Figure 11. The entire internal diameter of the bore 212 may be used to receive the pump-piston 290 thus utilizing all of the effective cross-sectional area of the bore 212 for larger volume and lower pressure.

The piston 201 is provided with an annular ring-receiving groove 225 for receiving an 0 type packing ring 226 generally similar to the ring 121 hereinabove described.

A compression coil-spring 227 is disposed within the barrel 10-a and has one end abutting the internal surface or shoulder 36 of the barrel 10-11; and the other end abutting one face of the piston 201. The coilspring 227 urges the piston 201 forwardly within the barrel 10-a. The spring 227 may be loaded orcompressed by pulling back the handle 135.

The piston 201 includes a generally cylindrical rearwardly-extending portion or sleeve 241, formed generally integrally with or fastened to the piston 201. The sleeve 241 has a generally cylindrical bore 240 communicating with the forward surface of the piston 201, for a purpose to be hereinafter described. The sleeve 241 also has a smaller bore 245 at its rearward end, and a largerdiametered counter-bore 242 having internal threads 243 therewithin. An 0 type sealing ring or other sealing ring or washer 244 is placed within the counter-bore 242 and around the piston-rod 202 and held securely therewithin by means of 'a threaded packing-gland 246. The

" packing-gland 246'h-olds the sealing ring or washer 244 "in place and provides a static fluid-tight seal between the V the shoulder 249 serve as locking means to be hereinafter described.

Within the bore 33-a, a generally cylindrical sleeve 260 is slidably mounted for axial movement. The sleeve 260 has an external cylindrical surface 261 which is just slightly smaller than the internal diameter of the bore 33-02, and has an internal bore 262 which is just slightly larger than the external diameter of the piston-rod 202. The sleeve 260 guides the piston-rod 202 within the rear end 32 of the barrel -a. The sleeve 260 also has its outer end slightly reduced in diameter, as at 263, which reduced portion slides within the internal bore 264 of a retaining nut 265 threadedly secured in a counter-bore 266 in the outer end of the bore 33a. The retainingnut 265 serves to guide the portion 263 of the sleeve 260 as well as to provide a shoulder against which the shoulder 267 {formed between the diameters ,261 and 263) may abut, so as to prevent the sleeve 260 from being withdrawn rearwardly from the bore 33-a. It is to be noted (with particular reference to Figure 12) that the reduced portion 263 of the sleeve 260 is sufiiciently long so that when the shoulder 267 "abuts the inner surface of the retaining-nut 265, the outer end 268 of the sleeve 260 extends beyond the end of the barrel 10-a where it may be contacted by the shoulder 269 of the handle 135. Thus, when the handle 135 is pushed forward, the surface 26% contacts the end 2680f the sleeve 260 and pushes it forwardly (and inwardly) a distance indicated by the arrows 270 inFigure 12.

A spring-pressed'plunger like or bolt-like locking finger 271 is adapted to engage the shoulder 249 of the packinggland 246 in a manner generally disclosed in Figure 12. The finger 271 is disposed at right angles to the axis of the piston-rod 202 and is held in place within a threaded bore 272 by a cap-nut 273 which slidably houses the finger 271 and isthreadedly secured in the bore'272. The cap-nut 273 is generally cup-shaped, having a recess 275 adapted to receive a compression-spring 274 therewithin. The spring 274 bears against the back wall of the recess 275 "and also against the bottom of a recess 276 in the locking finger 271. Thus, the spring 274 urges the locking finger 271 inwardly toward the piston-rod 202 and into juxtaposition with the cylindrical portion 247 of the packing gland 246, behind the shoulder 249 thereof.

When the piston 201 and the sleeve 241 (with the packing-gland 246 secured thereto) is pulled 'rearwardly 6 the piston 201 is urged forwardly by the compressed spring 227.

The piston may be kept in its rearinost position by the locking means above described without the necessity of holding it there manually, and it will remain in the locked position until the sleeve 260 is pushed forwardly by the handle 135 10 disengage the pin 271 from the shoulder 249.

To the front end of the piston-rod 202, a high-pressure plunger-piston 223 of smaller diameter is fastened coaxially with the piston-rod 202. The plunger-piston 223 is adapted .slidingly to enter the bore 216 and may be secured to the piston-rod 202 by engagement with the screw-threads 228 into the threaded bore 229 at the end of the piston-rod 202. The end of the 'pist0n-rod may .be split longitudinally and external screw-threads 230 provided on the split end with a nut 231 screwed thereon to ilock'the piston-jplunger223 against accidental loosening. The nut 231 also acts as a stop-member for the piston-rod 202 because it is adapted to move into the bore 240 until it strikes the rear end thereof. The piston-plunger 223 does not engage the check valve 218 when the handle .135 is 'all'the way forward. When the handle 135 is drawn outwardly, the piston-plunger 223 Will be Withdrawn from the bore 216. On the return stroke, .a .cham'fer or bevel in the sleeve 215 serves to guide the forward end of the pistonplunger 223 back .into the bore 216 ,(see Figure 13).

The piston-rod 202 and the piston-plunger secured thereto (either piston-plunger'223 or piston-plunger 290) may be drawn rearwardly into the bore 240 of the piston 201 even though the piston is in .its forwardmost position against the annular shoulder or abutment of the ring .205 (as is shown in'Figure 9). Thus, the pistonplunger maybe withdrawn from the bore 212 (or 216) to permit a charge of fiuidto enter the bore. The pistonby the handle 135 and the piston-rod 202, the tapered portion 250 of the packingland 246 engages the tip 281 of the locking finger 27-1, pushing it radially outward against the spring 274 as the tip 281 of the finger 27=1 travels along the frust-o-conical surface 250 of the packing-gland 246. As the packing-gland 246 m-oves further rearward, the tip 231 of the locking finger 247 is forced by the spring 274 behind the shoulder 249, thus preventing forward movement of the packing-gland 246 and locking the piston 201 at the rear of the barrel Iii-a, as is shown particularly in Figure 12.

.The sleeve 260 has a generally U-shaped slot 280 therein, into which the tip 281 of the locking finger 271 extends. The tip 281 is of smaller diameter than the body of the finger 271, with a tapered-shoulder 232 between .the tip 281 and the body 271.

A counter-bore 260-a in the sleeve 260 is adapted to receive the shoulder-portion 249 of the gland 246 therein and to permit the shoulder-portion 249 to travel beneath the locking finger 271.

A reduced-diametered portion 283 of the sleeve 260 is connected to the outer diameter 261 by a cam-like wedging surface 284. When the sleeve 260 is in its outermost position, the surface 283 is juxtaposed to the locking finger 271 and the finger 271 may moveradially inwardly to engage the gland 246 behind the shoulder 249. When the sleeve 260 is in its rearmost position as is shown in Figure 12, the locking finger 271 may engage the shoulder 249 of the packing-gland 246 and hold the piston 201 in the cocked position. To unlock the piston 201 from its rearmost position, the handle 135 is moved forwardly until the shoulder 269 thereof engages the outer end 268 of the sleeve 260. The sleeve 260 is pushed forwardly and the c-ammin-g portion 284 thereof engages the tapered portion 282 of the locking finger 271 and pushes the locking finger 271 radially outwardly and out of engagement with the shoulder 249 of the packing-gland 246. When the packing-gland 246 is released,

plunger then may be pushed forwardly into the bore, forcing the fluid therein past the check valve 218.

When the handle I35 and the piston-rod 202 are withdrawn still farther to the rear,-the nut 231 (or the largerdiametered plunger 290) will contact the end of the bore 240 in the sleeve241, whereby the piston 201 may be withdrawn rearward'ly and engaged by the locking finger 271 (in the fully retracted position of the piston).

- When it is .desired to use the grease-gun of Figure 9, the cap member 209 may be unscrewed from the ring 205, the piston-rod 2'02 drawn back as far as possible (compressing the spring 227 and locking the piston 201 in its retracted position) and the barrel 10-0 filed with lubricant through the opening 232 by any suitable means. Alternatively, the lubricant, if sufficiently fluid, may be sucked up from a container by inserting the Opening 232 of the barrel 10-a below the surface of the lubricant (inan original lubricant vending container) and withdrawing the piston to its rearward locked position. Air-pressure will force the lubricant into the barrel. Then the filled barrel may be removed from the container and the cap member 209 replaced.

The check valve 218 is held against the seat 219 with suflicient force to prevent the discharge of lubricant through the head-portion 222 when the piston-plunger is withdrawn from the bore even though the piston 201 is unlocked from the rear end of the barrel and the coil spring 227 is compressing the lubricant in the barrel 10-a between the forward side of the piston 201 and the nozzle member 219. However, when the piston-rod 202, moving independently of piston 201, is pushed forward to force the piston-plunger (223 or 220) into the bore or cylinder (216 or 212 respectively), the fluid in the bore will be forced past the check valve 218 and out through coupling 222. When the piston-plunger is withdrawn from the bore, additional lubricant will be drawn into said bore from the barrel 10-a by the vacuum created in the bore; lubricant being constantly urged toward the bore by the spring-pressed piston 201.

In the embodiment of the invention shown in Figure I 13, there is shown a modified form generally like that of Figure 9, but of smaller dimensions, adapted to provide a grease-gun of smaller grease-capacity.

Referring now to the embodiment shown in Figures 15 and 16, the barrel -11, piston 201, coil spring 227, locking means 246, 260, 273 and handle 135 are generally the same as heretofore described. The piston 201 will be retained in its rearwardmost position when the handle 135 (secured to the piston-rod 301 by the threads 302) is retracted rearwardly so as to draw the piston 201 towards the rear of the barrel 10-11 and engage the locking-means on the piston with the locking means at the rear 32 of the barrel.

In the embodiment shown in Figure 15, the pistonrod 301 is somewhat shorter in length than the pistonrod 202 shown in Figure 9. When the piston 201 is in its forwardmost position, as shown in Figure 15, the stopmember 303 extends no farther forward than the inner end of the bore 240. Thus, the piston may be moved rearwardly to draw in a supply of lubricant by suction or to permit a supply to be placed in the forward end of the barrel by any suitable means.

As soon as the handle 135 is moved forward to engage the sleeve 260 and disengage the locking means, the coil spring 227 will urge the piston 201 forwardly within the barrel to maintain constant pressure on the lubricant contained therein.

A ring or nipple 205, similar to that described in reference to the embodiment of Figure 9, is screwed into the internal threads 204 formed at the front end of the barrel 10a. The ring 205 provides a stop for the piston 201 and also provides a coupling or connecting member between the barrel 10-a and the cap member 306; the cap 306 having relatively coarse external threads 307, which engage the internal threads 206 on the sleeve 205.

A gasket 211 efiects a seal between the ring 205 and the cap 306.

The cap-member 306 is formed with a bore 308 and with a passageway 309 extending inwardly from the rear surface thereof, with a lubricant conduit 310 extending at right angles thereto and communicating therewith. A high pressure piston-plunger 311 slidingly fits within the conduit 310 and projects therebeyond through a bushing 312 disposed in a counter-bore or recess 313 at one end of the conduit or high pressure cylinder 310. A sealing gasket 314 is held in the counter-bore 313 by the bushing 312 to provide a fluid-tight seal between the piston-plunger 311 and the cap member 306. V

The outer end of the high pressure piston-plunger 311 is pivotally connected, as at 315, to a lever-arm 316, having a handle 317 formed at one end.

The lever-arm 316 may be pivotally connected at its forward end to the cap member 306 by one or more links318 which are secured at one end to the lever-arm 316 by a pivot-pin 319 and at the other end by a pivotpin 320 to a projection 321 of the cap member 306.

A check valve 218, pump-cylinder member 215 and head portion 222 may be supported at the discharge end of the conduit 310 in a manner similar to the pumpcylinder, valve and head portion described with reference to Figure 11.

The barrel 10a of Figures and 16 may be filled by removing the cap member 306 from the ring 205, inserting the open end of the barrel 10-a within a body of lubricant, and following the filling procedure above described. The grease-filled barrel may be removed from the body of lubricant and the cap member 306 attached thereto. A forward push of the handle 135 will then unlock the piston 201 which piston will urge the body of grease'in the barrel toward the cap member 306, and particularly into the bore 308 and passageway 309.

When the lower end of the piston-plunger 311 is drawn upwardly beyond the passageway .309 (by the lever-arm 316) the vacuum created in the cylinder 310 will draw lubricant into the high pressure cylinder 310 through the passageway 309. On the down-stroke of the piston-plunger 311, the lubricant in the cylinder 310 will be forced therefrom past the check valve 218 under high pressure.

The upward movement of the lever 316 is limited by contact of the edge 322 thereof with the edge 323 of the link 318 so that the piston-plunger 311 will not be entirely withdrawn from the cylinder 310.

Having descrbed my invention, what I claim as new and desire to protect by Letters Patent is:

1; A grease-gun including a cylindrical barrel having one end thereof formed integrally with the side of the barrel and being substantially closed and having the bore at its other end internally screw-threaded, a connectorring having an external annular shoulder transversely of its axis, intermediate the ends of said ring, the outer surface of said connector-ring between the inner diameter of said shoulder and the end of said connector-ring being externally screw-threaded, the bore of said connector-ring being internally screw-threaded inwardly from the opposite end of said connector-ring, said connectorring being screw-threadly attached to said barrel by telescoping and threading its aforementioned externally screw-threaded portion into the internally screw-threaed end of the bore of said barrel, a cap-member having an externally screw-threaded portion adapted screw-threadedly. to telescope into the internally screw-threaded portion of said connector-ring and having a discharge-outlet therein and being screw-threadedly attached to said connector-ring, the screw-threads between said cap-member and said connector-ring being of relatively coarse pitch and being less resistant to relative rotation between said cap-member and said connector-ring than the screwthreads between said barrel and said connector-ring which are of relatively fine pitch, whereby said cap-member may be rotated relative to said barrel and said connector-ring without relative movement between said barrel and said ring.

2. A grease-gun including a cylindrical barrel having one non-removable end integral therewith and having an axial bore extending through said integral end, a removable cap-member attached to the other end of said barrel, a piston axially sildable within said barrel, a piston-rod extending through said barrel and through the bore within the integral end of said barrel and extending outwardly therefrom, said piston-rod passing through an axial bore in said piston, fluid-tight sealing means between said piston and said barrel and between said piston and said piston-rod, a compression spring between the integral end of said barrel and said piston adapted to urge said piston away from the integral end of said barrel at all times, a counter-bore in the end of said piston and shoulder-means on said piston-rod adapted to engage said piston within said counter-bore whereby said piston may be drawn by said piston-rod toward the integralend of said barrel against the compression of said spring with the inner end of said piston rod disposed substantially entirely within said counter-bore, lockingmeans on said piston, co-operating radially movable locking means on said barrel adapted to engage the locking means on said piston when said piston is drawn rearwardly by said piston-rod and adapted to hold said piston at the integral end of said barrel against the compression of said spring, independently of the position of said piston-rod, release-means in said barrel adapted to move said locking means on said barrel radially outwardly when said piston-rod is moved forwardly to a predetermined position thereby permitting said spring to urge said piston forwardly toward said cap-member, said cap-member having an axial bore therein, a plunger-piston secured to the forward end of said piston-rod adapted to enter the bore of said cap-member when the piston-rod is in its forwardrnost' position, valve-means in said axial bore adapted to prevent the passage of fluid therethrough when said plunger-piston is withdrawn from said bore, said valve-means being actuated by fluid passing through said bore when forced forwardly therethrough by said plungerpiston.

3. In a grease-gun including a barrel having one end of its bore internally screw-threaded, a piston, a pistonrod, 21 cap-member having a reduced-diametered rearward portion externally screw-threaded, a connector-ring having an external annular shoulder transversely of its axis, intermediate the ends of said ring, the outer surface of said connector-ring between the inner diameter of said shoulder and the end of said connector-ring being externally screw-threaded, the bore of said connector-ring being internally screw-threaded inwardly from the opposite end of said connector-ring, said connector-ring being screw-threadedly interposed between said barrel and said cap-member with its externally screw-threaded portion telescoped into the internally screw-threaded end portion of the bore of said barrel, and with the externally screw-threaded portion of said cap-member being screwthreadedly telescoped into the internally screw-threaded portion of said connector-ring, said connector-ring having coarser screw-threads between it and said cap-member than between it and said barrel, whereby said cap-member may be removed from said connector-ring without removing said connector-ring from said barrel, an axial bore within said cap-member adapted to receive one end of said piston-rod when said piston-rod is in its forwardmost position, said piston-rod extending through said ring when in its forward position, and valve-means within said bore, said valve means being actuated by fluid forced through said bore by said piston-rod.

4. In a grease-gun including a barrel and a piston reciprocable within said barrel, locking-means whereby said piston may be detachably secured to said barrel, said locking means including a radially disposed pin at one end of said barrel and spring-urged toward the axis of said barrel, a sleeve-portion slidable within said barrel and adapted to push said pin radially outward in one position and to prevent said pin from moving radially inward in another position, a shoulder-member on said piston adapted to engage said pin when said piston is in its rearwardmost position, said shoulder-member adapted to move said sleeve-portion rearwardly when said piston is in its rear- Wardrnost position whereby said pin may move radially inward into engagement with said shoulder-member, and said sleeve-portion adapted to move said pin radially outward and out of engagement with said shoulder-member when said sleeve-portion is moved forwardly a predetermined distance.

5. In a grease-gun including a barrel-portion and a capmember portion, a piston-rod reciprocable Within said barrel and said cap-member, a compression spring within said barrel adapted to urge said piston in one direction, locking means in said barrel and on said piston whereby said piston may be secured at one end of said barrel against the compression of said spring, means within said barrel whereby said locking means may be disengaged so as to permit said spring to urge said piston forwardly away from said locking means, an axial bore within said cap-member adapted to receive said piston-rod and into which said piston will force grease when said piston is in its unlocked position with grease or similar lubricant is entrained within said barrel between said piston and said cap-member, and valve-means in said bore to prevent the passage of lubricant through said bore except when said piston-rod enters said bore and forces lubricant past said valve-means.

6. A cap-member for grease-guns consisting of a generally concave tapering body including an inwardly extending shoulder-portion in said cap-member and having an axial bore therethrough, said axial bore having a threaded counter-bore at the outer end thereof, a sleeveportion threadedly secured in said counter-bore and wholly concealed therewithin and an axial bore within said sleeve-portion and a valve-member within said lastnamed axial bore.

10 7. In a grease-gun, a lubricant-receiving barrel open at one end and having an axial bore through the integrally closed opposite end, a piston-rod adapted to pass through 7 said bore and slidable within said barrel, a piston adapted I to slide within said barrel, a peripheral groove on said,

piston and fluid-tight sealing means within said peripheral groove adapted to establish fluid-tight slidable contact between said piston and said barrel, said piston having an axial bore therethrough adapted to receive said pistonrod, and fluid-tight sealing means within said piston surrounding said piston-rod whereby a fluid-tight slidable seal may be maintained between said piston and said piston-rod, said piston including a peripheral shoulder-portion at the rear end thereof, locking-means at the integral rear end of said barrel adapted to engage said peripheral shoulder, said locking means including a radially-extending pin spring-urged radially inwardly, an axially slidable sleeve-portion in said barrel adapted to contact and retain said pin in an outward position when said sleeve is in its forward position and adapted to permit said pin to move radially inwardly when said sleeve is moved to its rearward position, said sleeve movable rearwardly when engaged by the peripheral shoulder portion of said piston when said piston is drawn rearwardly by said piston-rod, said sleeve movable forwardly when engaged by a handle secured to said piston-rod, and cam-means on said sleeve adapted to move said pin radially outwardly when said sleeve is moved forwardly thereby to release said peripheral shoulder on said piston and permit said piston to move forwardly away from the integral end of said barrel.

8. A one-piece die-cast cap-member for the barrels of grease-guns, said cap-member having a larger-d-iametered outer surface near the rear end thereof and a smallerdiametered outer surface near the front end thereof, and the generally tapered outer surface intervening these two diameters, an axial bore through said cap-member, a portion of said bore being internally screw-threaded, telescopically to receive and screw-threadedly to engage a tubular metal-insert of harder metal, and having an internal shoulder against which such insert may bear to limit its entrance into said cap-member, said cap-member having a reduced-diametered portion extending rearwardly of the aforementioned larger-diametered outer surface thereof, and forming a transverse shoulder therebetween, said reduced-diametered portion being externally screw-threaded, and a tubular member of harder metal telescoped into the bore of said die-cast member, said tubular member having a high pressure cylinder-bore at the rear end thereof and a larger valve-chamber bore in the front end thereof including a Valve-seat intervening said two bores thereof.

References Cited in the file of this patent UNITED STATES PATENTS 391,956 Frager Oct. 30, 1888 831,758 Yanacopoulo Sept. 25, 1906 1,587,597 MacLellan June 8, 1926 1,659,204 Klems Feb. 14, 1928 1,695,627 Zerk Dec. 18, 1928 1,790,914 Gray Feb. 3, 1931 1,793,493 Kreidel Feb. 24, 1931 1,951,504 Morris Mar. 20, 1934 1,968,231 Thomas July 31, 1934 2,055,602 Dodge Sept. 29, 1936 2,137,740 Gray Nov. 22, 1938 2,317,872 Zimt Apr. '27, 1943 2,361,125 Rotter Oct. 24, 1944 2,361,126 Klein Oct. 24, 1944 2,526,374 Le Clair, Oct. 17, 1950 FOREIGN PATENTS 112,768 Austria Apr. 10, 1929

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