Auto Research Corporation

Carl H Smith

August X Sidler

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.

Dual timer with delay

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. The charging rate is typically adjustable over a range between 2-90 seconds in charging from said first to said second predetermined level and is further adjustable over a range which is typically of the order of a few minutes to several hours when discharging from said second to said first predetermined level so as to dispense lubricant during a period of from 2-90 seconds every two hours, for example, said interval being repeated on a cyclic basis.

Long time period astable multivibrator circuit with independently

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. elements in the oscillator circuit and which typically may be of the order of hours, or even days, continues until the voltage output of the logical gating circuitry reaches a predetermined threshold level causing the bistable circuit to reset and turn off the oscillator and causing the activation of the electronic switch. The alarm activated by the electronic switch may be a lamp which is energized to indicate that an unusually prolonged period of time has occurred since the last pump operation. Operation of the timing circuit is not reinitiated until the pressure switch again undergoes a switch closure operation which automatically sets the bistable circuit and turns the lamp off. The delay of the timing circuit is not significantly affected by transients.

Electronic pressure cycle indicator

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. Recharging of the capacitance does not occur until the pressure switch again undergoes a switch closure operation which automatically sets the bistable flip-flop and turns the lamp off. Operation of the circuitry so as to charge the capacitor rapidly and allow for a slow discharge rate serves to substantially reduce capacitance leakage problems.

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Spring Valley, NY, United States of America

Carl H Smith