Abstract: In a lubricator which employs an injection pump connected with an air line to a tool by a branch air line through which pulses of air under pressure are transmitted to the pump for operating the same, a pulse counting mechanism interposed in the branch air line and including a first valve which opens the branch air line for operating the pump after each series of pulses of a predetermined number. The first valve carries a check valve operable to relieve the pressure of air trapped in the pump incidental to closing of the branch air line.

Abstract: Pump body has a cylindrical chamber within which a spool-shaped insert fits. The insert has a central cylindrical bore within which the injection plunger works and has an external annular groove communicating with the bore through a lubricant supply port having a diameter smaller than that of the bore. Lubricant is furnished to the bore through an opening in the pump body which communicates into the annular space defined by the insert groove. The fit between the plunger and bore is interrupted only through the arcuate extent of the diameter of the lubricant supply port.

Abstract: In a lubricator which employs an injection pump controlled by an air flow sensor to force a predetermined quantity of lubricant into an air line or tool upon each starting of air flow therein, an improved sight indicator for lubricant flow which comprises a ball in a 45.degree. bore in a portion of the lubricant flow path in a transparent dome, the ball seating gravitationally at the bottom of the bore in static condition of the lubricant and being movable upwardly responsive to pulsations of lubricant flow through the flow path, the dome being bodily turnable against frictional resistance provided by O-rings to orient the bore axis vertically.

Abstract: In a lubricator which introduces lubricant from a reservoir into an air line through a metering orifice under pressure differential induced by a flow of air through the lubricator, the orifice is replaced by a resiliently flexible tube whose walls are adjustably squeezed together along a substantial length by a pair of threaded clamp elements to provide a metering restriction which is relatively long and therefore permissibly having a relatively large sectional area which is more accurately adjustable and clog free than the conventional orifice.