Abstract: Pressure responsive piston valve with spring controlled detent balls; a detent pressure spring extends longitudinally through the piston and urges a biasing ball against detent balls which are longitudinally offset from the biasing ball; the detent balls are driven into a detent groove in the cylinder for the piston; pressure on the piston forces the detent balls out of the detent groove; calibrating means for the spring.

Abstract: A solid state dual timer with adjustable "long" and "short" time intervals preferably providing a long normally operating period between consecutive test periods which are utilized for test purposes, wherein a "delay" interval is provided at the initiation of each test period to allow the test conditions being imposed a sufficient time to settle. A highly advantageous application resides in the field of automated lubrication systems in which periodic pressure tests to monitor system integrity are performed, for example, every hour, the tests requiring a relatively brief time interval, the "delay" interval being of a length sufficient to allow the system pressure to build up before the test instruments are activated. The normally operating interval and the test and "delay" periods are all adjustable.

Abstract: The output from the pump chamber of a higher volume piston pump is divided between a return bypass and the pump chamber of a smaller volume piston pump; the piston of the high volume piston pump is periodically raised by a cam to draw fluid into the pump chamber; when this piston is released, a spring forces fluid from the high volume pump chamber; the pump chamber of the small volume pump is connected with the cam such that the volume of the low volume pump chamber decreases, thereby pumping out the fluid in that chamber, when the large volume pump chamber is taking in fluid, and vice versa; appropriate valves ensure that flow is only in the desired direction; adjustment and calibration means are provided for the low volume pump.

Abstract: A solid state electronic dual timer which, in one preferred embodiment, is utilized for dispensing a measured quantity of lubricant at predetermined time intervals. A continuously operating pump is selectively connected to the devices requiring lubricant by a control valve means. A capacitor is charged through a first circuit path from one predetermined level until it reaches a second predetermined level during which time the control valve means for dispensing the lubricant is energized. As soon as a second predetermined level is achieved, the pump means is deenergized, at which time the capacitor is caused to discharge towards said first predetermined level at a slow rate.

Abstract: A fluid pressure sensor is employed as a safety device for sensing lubricant pressure levels. A timer is activated to turn on a pump at regular intervals to provide lubrication at such intervals. Pump operation supplies lubricant to a dispensing network which, in turn, causes closure of a pressure switch for activating an oscillator. A comparator circuit compares the accumulated count of oscillator pulses against a predetermined threshold level to trigger an electronic switch which activates an alarm. The pressure switch closure sets a bistable circuit which, in turn, activates said oscillator circuit for incrementing a programmable binary counter circuit. The long-time interval before actuating logical gating circuitry, which interval is adjustable by programming of the binary and/or the R.C.

Abstract: An injector for grease or the like fluid: the injector includes two separate pressure cylinders; a respective piston in each cylinder, and each cylinder being divided into two chambers by its respective piston; an inlet upstream of the upstream piston; an outlet downstream of the downstream piston; and connections between the two chambers of the downstream cylinder and between the upstream and downstream cylinders.

Abstract: Fluid pressure sensing means for sensing lubricant pressure levels. Means are activated to turn on a pump at regular intervals to provide lubrication at such intervals. It is desired to indicate failure of subsequent operation of the pump after a time interval greater in duration than the aforesaid periodic intervals. Pump operation causes closure of pressure switch which causes capacitance means to charge during the switch closure interval. As soon as the capacitance is charged beyond a predetermined threshold level, bistable means are set which in turn sets up a discharge path for the capacitor. The long-time constant of the discharge path, which is adjustable and which typically may be of the order of hours, continues until the voltage across the capacitor drops below a second predetermined threshold level resetting the bistable flip-flop. The reset operation triggers a switch means for illuminating a lamp which indicates that a prolonged period of time has occurred since the last pump operation.