Airline lubricator
The present invention is directed to airline lubricators, and more particularly to a device for automatically injecting lubricant into a compressed airline fed to a pneumatic tool or the like. 
     A general object of the present invention is to provide an airline lubricator of simple construction which is economical to manufacture and which provides reliable service over an extended operating lifetime. 
     A more specific object of the invention is to provide an airline lubricator of the described type which is adapted to be coupled to an airline in any desired orientation, and which feeds lubricant to the airline only when air is flowing therein. 
     Yet another object of the invention is to provide an airline lubricator of the described type wherein the amount of lubricant fed to the airline may be readily adjusted. 
    
    
     The invention, together with additional objects, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which: 
     FIG. 1 is an elevational bisectional view of a lubricator in accordance with the invention taken in an axial plane, as along the line 1--1 in FIG. 2; 
     FIG. 2 is an elevational view of the inlet end of the lubricator of FIG. 1; 
     FIG. 3 is a fragmentary sectional view taken along the line 3--3 in FIG. 1; and 
     FIG. 4 is an elevational view of the outlet end of the lubricator. 
    
    
     The drawings illustrate a presently preferred embodiment 10 of an airline lubricator in accordance with the invention as comprising an enclosure or casing 12 including a hollow cylindrical tube or pipe 14 defining a central air passage 16 of uniform diameter extending along the tube axis. An inlet head 18 is integral with tube 14 at one end thereof, and includes a tapered internally threaded opening 20 aligned with passage 16 for defining an air inlet. An outlet head 22 is threaded onto the opposing end of tube 14 and includes an internally threaded tapered opening 24 aligned with passage 16 for defining an air outlet. An airline may be connected to openings 20,24 using suitable fittings (not shown). 
     A cylindrical sleeve or casing wall 26 is captured between heads 18,22 and cooperates therewith to define an annular chamber 28 coaxially surrounding air passage tube 14 intermediate the air passage ends. An annular diaphragm 30 of resilient elastomeric oil-resistant construction has a circumferentially continuous bead 32 at one end captured in sealing compression by wall 26 against a radially facing shoulder 34 on head 18. A second circumferentially continuous bead 36 at the opposing end of diaphragm 30 is elastically received in tension over tube 14 adjacent head 22. In its relaxed state (not shown in the drawings), diaphragm 30 extends from beam 32 along the inner surfaces of wall 26 and head 22, and along tube 14 to bead 36. Thus, diaphragm 30 effectively divides annular chamber 28 into an annular air pressure chamber 38 adjacent inlet head 18 and an annular oil reservoir 40 adjacent outlet head 22. 
     An air pressure tube 42 extends at an angle through tube 14 at the juncture of the latter with inlet head 18. The end 44 of tube 42 within air passage 16 is disposed at about the axis thereof and is cut or formed at an angle so as to be oriented in a radial plane facing in the direction of inlet opening 20. Thus, tube 42 feeds inlet air pressure to chamber 38. An annular resilient O-ring 46 is sealingly captured in compression by wall 26 against a radially facing shoulder 48 on head 22. A lubricant passage 50 extends within head 22 from reservoir 40 parallel to the axis of air passage 16. A metering tube 51 is press-fitted into head 22 and extends in the radial direction from the reservoir-remote end of passage 50 into air passage 16, terminating adjacent the air passage central axis. A set screw 52 is threaded into head 22 in axial alignment with tube 51 and has an insert 53 at the inner end thereof which cooperates with the opposing radially outer flat end of tube 51 for varying the effective opening size of the metering tube input end, and thereby varying the amount of lubricant fed to air passage 16 for a given drop in pressure through air passage 16. 
     A check valve 54 is carried by head 22 for preventing flow of lubricant from metering tube 51 into passage 16 in the absence of air flow in the latter. Check valve 54 comprises a head 55 threadably received in enclosure head 22, and a hollow sleeve or shank 56 extending integrally and coaxially therefrom in diametrically opposed alignment with metering tube 51. A coil spring 58 is carried internally of sleeve 56 and biases a valve element ball 60 against the opposing flat end of metering tube 51. As best seen in FIG. 4, ball 60 is disposed at about the central axis of air passage 16. The outside diameter of ball 60 is less than the inside diameter of sleeve 56. A ring 63 surrounds sleeve 56 and engages the opposing threads in head 22 for holding head 55 in desired set position. 
     FIG. 3 illustrates the reservoir fill mechanism as comprising a fill passage 62 extending within head 22 axially and then radially from reservoir 40. A screw 64 closes the reservoir-remote end of passage 62. A ball 66 is captured by a retaining clip 68 within passage 62 adjacent reservoir 40 to prevent back-flow of lubricant under pressure to screw 64. 
     In operation, in the absence of air flow in passage 16, metering tube 51 is closed by valve ball 60 and passage of lubricant to the airline is blocked in all orientations of lubricator 10. As air flow begins within passage 16, an increase in air pressure with chamber 38 urges lubricant from within reservoir 40 through passage 50 and tube 51 against ball 60. When lubricant pressure is sufficient to overcome spring 58, ball 60 will be urged away from metering tube 51 and lubricant will be aspirated into the flowing air. Transparent wall 26 permits observation of lubricant reservoir 40, which may be refilled through passage 62 (FIG. 3) when empty. It will be appreciated that screw 52 and head 55 are accessible from externally of enclosure 12 and may be readily adjusted during operation of the lubricator. Likewise, ball valve 66 permits removal of screw 64 and filling of the reservoir without shutting down the airline and/or removing lubricator 10 therefrom. Screw 52 adjusts the amount of lubricant fed to metering tube 51 as a function of air pressure, and head 55 adjusts the effective spring pressure on valve ball 60.