The lubricator of the invention is a one-shot or non-continuous type. It has a first reservoir within which to receive a charge of lubricant, and a second reservoir from which to expel a charge of lubricant, and a piston slidable therebetween for moving lubricant from the first reservoir to the second reservoir, and also for discharging lubricant from the second reservoir and externally of the lubricator. Upon the piston moving, slidably, in a first direction it creates a partial vacuum in the first reservoir and, consequently, ingests lubricant into the first reservoir. Then, as the piston moves in the second, opposite direction, it diminishes the volume of the first reservoir, and displaces lubricant therefrom through a channel formed centrally in the piston. The lubricant conducted through the channel is deposited in the second reservoir, and is expelled therefrom, by the piston, when next the piston moves in the first, slidable direction.

This invention pertains to lubrication devices, and in particular to 
non-continuous or one-shot type lubricators such as are used for single 
injection lubrication of machinery or apparatus, such as air motors. 
Non-continuous or one-shot type lubricators are especially useful for 
lubrication of machinery or apparatus, viz., air motors, which commonly 
operate for short durations of time. For such lubrication applications, 
one shot or one injection of lubricant, at the beginning of the operation 
of the machinery or apparatus, is sufficient for the brief operational 
duration. 
Prior art one-shot lubricators, typically, employ a check-ball valve, and 
are self-priming. However, these known lubricators frequently experience 
problems arising from an unduly pressurized lubricant supply. In the 
latter circumstance, the lubricator will proceed to malfunction, and 
lubricant will flow continuously therethrough, from the lubricant supply 
line, to the using end item (air motor, or the like). Of course, this not 
only floods the end item, but also wastes lubricant. 
It is an object of this invention to set forth a lubricator of the one-shot 
type of simple and inexpensive manufacture which, nonetheless, will not 
exhibit the faulty, through-flow of lubricant with a pressurized supply of 
lubricant. 
It is particularly an object of this invention to set forth a lubricator, 
comprising a housing; said housing having a chamber formed therewithin; 
and means within said housing subdividing said chamber into a pair of 
separate, lubricant-receiving reservoirs; said housing having a first port 
formed therein which opens into one of said reservoirs for supplying 
lubricant thereto; and said housing having a second port formed therein 
which opens into the other of said reservoirs for expelling lubricant 
therefrom; wherein said subdividing means comprises means for moving 
lubricant from said one reservoir to said other reservoir.

As shown in the FIGURE, the embodiment of the lubricator 10 comprises a 
housing 12 constituted of a cylindrical body 14 and an end cap 16. The 
body 14 and end cap 16 are externally and internally threaded, 
respectively, for threadedly mating together. The end cap 16 also has a 
reduced-diameter portion 18 which defines an adapter for threadedly 
engaging and communicating with a source of pressured fluid. In the 
exemplary arrangement shown, portion 18 is threadedly intruded into a 
compressed air supply conduit 20 which communicates with an air motor (not 
shown). As will be understood, conduit 20 supplies operative compressed 
air to the air motor, and the lubricator 10 expels lubricant into the 
conduit for lubrication of the air motor. 
Housing 12 defines a chamber 22 therewithin. Chamber 22 has a first 
cylindrical portion 24 at one end thereof which opens into a second, 
larger cylindrical portion 26. A dual-ended piston 28 is slidably disposed 
in the chamber 22. A first plunger-type end 30 of the piston reciprocates 
within cylindrical portion 24, and in close-fitting engagement with the 
walls of said portion. Adjacent the opposite end of the piston 28 is 
formed a circular land 32 which reciprocates in close-fitting engagement 
with the inner surface of cylindrical portion 26. Land 32 carries a seal 
34 to define a sealing engagement with the latter-mentioned surface, and 
end 30 carries a seal 36 to define a sealing engagement between the end 30 
and the inner surface of portion 24. 
An annular shoulder 38 formed within the body 14 receives one end of a 
compression spring 40. The other end of the spring 40 bears against land 
32 to urge the piston 28 normally in the disposition shown. The piston 28 
has a channel 42 formed centrally therethrough from one end thereof to 
open onto the cylindrical portion 24, and to adjacent the other end 
thereof. Piston 28 has a nose portion 44 at the end thereof opposite the 
plunger-type end 30. A narrow bore 42a communicates the channel 42 with 
the base of the nose portion 44. However, an O-ring seal 46 is set about 
the base of the nose portion 44 to close off the bore 42a. 
Portion 18 of the end cap 16 has a port 48 formed therein which reduces 
into a metering orifice 50. Orifice 50 opens into an area 52 of chamber 22 
which is sealed off from the rest of chamber 22 by the seal 34. Area 52 
defines a second lubricant-receiving reservoir, whereas chamber 22 
generally and cylindrical portion 24 thereof in particular, define a first 
lubricant-receiving reservoir. The lubricator 10 admits lubricant into the 
first reservoir, i.e., chamber 22 and its portion 24, and conducts it, via 
the channel 42, to the second lubricant-receiving reservoir, i.e., area 
52, to be expelled from the latter. To this purpose, body 14 has a 
lubricant-supply port 54 formed therein for communication both the chamber 
22 and its cylindrical portion 24. Finally, between the flat end surface 
of the nose portion, which flat end surface comprises a fluid-impingement 
surface for compressed air from conduit 20, and the metering orifice 50, 
is interposed a filter element 56. Element 56 filters such lubricant as is 
passed therethrough, and is purged of particulate by compressed air 
conducted therethrough, in a contrary direction, from the conduit 20. 
Typical operation of the lubricator 10 will be explained as it will 
function in lubrication of an air motor, although such an air motor is not 
shown. Compressed air is conducted through conduit 20 to such an air 
motor, to cause operation thereof, and some of the air will enter the 
lubricator 10 via the port 48 and metering orifice 50. Consequently, the 
piston 28 will be moved against the bias of the spring 40. The 
plunger-type end 30 of the piston 28 will enter the cylindrical portion 24 
of the body 14 and force any lubricant therewithin out through the channel 
42, and under the seal 46, into area 52. When the air motor is shut down, 
the compressed air supply through the conduit 20 ceases; therefore, the 
spring 40 is free to return the piston to the extreme left-hand 
disposition (as shown in the FIGURE). Upon returning to this disposition, 
the piston 28 does two things. For one, it expels lubricant priorly 
conducted to area 52 therefrom and into the conduit 20. Such expelled 
lubricant, then, is positioned for conduct to the air motor (or whatever) 
when next it is turned on again. Also, the aforesaid return of the piston 
28 to its normal position creates a partial vacuum in cylindrical portion 
24; this partial vacuum ingests lubricant from the supply thereof which is 
in communication with port 54. This ingested lubricant, then, awaits 
another translation of the piston 28, contrary to the bias of the spring 
40, for its transfer, via channel 42 (and bore 42a), to the alternative 
repository or reservoir of area 52. 
The end of cylindrical portion 24 which communicates with the port 54 has a 
slightly greater diameter than the remainder of portion 24. This provides 
a fine clearance through which the vacuum-ingested lubricant can negotiate 
past the end of the plunger-type end 30 of the piston 28 to enter portion 
24 therebeyond. 
Consider now the situation in which the lubricant supply at port 54 becomes 
unduly pressurized. Here, it will be appreciated, the lubricant is quite 
effectively prevented from flowing through lubricator 10. The piston 28 is 
held fast against the inner surface of the end cap 16, and the O-ring seal 
46 is sealingly compressed between the latter surface and the nose portion 
44. The seal 46 cannot lift from the bore 42a, and the piston 28 cannot 
withdraw from area 52. 
While I have described my invention in connection with an embodiment 
thereof which represents the best mode contemplated by me for carrying out 
the invention, it is to be clearly understood that this is done only by 
way of example and not as a limitation to the scope of my invention, as 
set forth in the objects thereof and in the appended claims.