Lockheed Martin Tactical Systems, Inc.

Lockheed Martin Corporation

Unisys Corporation

Eugene T Mullin

S James Lazzarotti

Clifford J Bader

Edward A Wojtowicz

Jess Nadel

A system and method is disclosed for feedback velocity control of a D.C. motor. The system includes a motor (30) which is represented by its circuit equivalent--a series combination of an inductance (32), a resistor (34) and a back EMF source (36). The drive to the motor (30), supplied by a controller, is periodically inhibited by timing logic (22) and AND gate (20). Once the inductive transient decays via clamping diode (38) such that the motor current is zero, switch (40) is closed and the internally generated motor voltage is sampled by a capacitor (42). A/D converter (44) transforms the sampled value to a digital value and sends it to the controller. The controller compares it to a predetermined desired value then makes the necessary adjustments to the drive signal.

System and method for velocity control of a D.C. Motor

Apparatus and method are provided for receiving a flow of packages such as parcels or bundles, dividing it into plural streams for easier singulation, singulating each such stream, and delivering the produced packages one at a time to a user, each stream being provided to a different user. Downstream sensors are used to control a deflector which in turn divides a received flow of packages into multiple such flows and apportions the received packages among the two output flows. Singulation of each such output flow is accomplished by a plurality of inclined belts which each moves a received package upward and over its peak to drop for entry into the next stage downstream, thereby singulating the received flow in stages. These belt stages are individually controlled by further downstream sensors and motors which prevent movement of upstream such belt(s) if one or more packages, indicating a flow blockage, is sensed downstream. The output of the singulator is provided to a slide that has a series of motor-controlled detents to deliver packages to the downstream user one at a time.

Apparatus and method for handling flow of packages

Apparatus and method are provided for determining and indicating if certain types of circuit failures have occurred in a D.C. motor circuit such as a locked rotor condition, a short-circuit or an open circuit. The method includes the steps of, and the apparatus involves applying a voltage to two leads of the D.C. motor sufficient to cause motor rotation, determining if flyback exists, determining if back EMF exists, and, finally, if a back EMF does not exist and flyback does exist then indicating a locked rotor condition. However, if a back EMF does not exist and flyback does not exist then an indication is provided that either an open-circuit or short-circuit condition exists. The same apparatus and method can be used with a voltage not sufficient to cause motor rotation, although given this limitation only flyback can be detected, so that only an open-circuit or short-circuit condition can be indicated.

System and method for detecting D.C. motor circuit failures

Apparatus and method are provided for determining indicating if certain types of circuit failures have occurred in a D.C. motor circuit such as a locked rotor condition, a short-circuit or an open circuit. The method includes the steps of, and the apparatus involves, applying a voltage to two leads of the D.C. motor sufficient to cause motor rotation, determining if flyback exists, determining if back EMF exists, and, finally, if a back EMF does not exist and flyback does exist then indicating a locked rotor condition. However, if a back EMF does not exist and flyback does not exist then an indication is provided that either an open-circuit or short-circuit condition exists. The same apparatus and method can be used with a voltage not sufficient to cause motor rotation, although given this limitation only flyback can be detected, so that only an open-circuit or short-circuit condition can be indicated.

System and method for detecting fault conditions in a direct current

An apparatus (10) for producing a singulated flow of correctly oriented flats (100 or 160) includes an input conveyor (12), a plurality of singulating conveyors (14, 16, and 18), and a skew correction station (20). A stack of flats (100 or 160) is deposited onto an inclined surface (42) of the input conveyor (12). The input conveyor (12) produced a running shingle of flats by frictionally engaging and pulling the bottom most flat in the stack. The plurality of singulating conveyors (14, 16, and 18) convert the running shingle into a singulated flow using frictional, inertial, and gravitational forces. By advancing conveyor (16) while halting conveyor (14), a flat (102) is pulled from underneath flat (108) with flat (108) remaining stationary. By operating conveyor (16) in a pulsed acceleration mode, passenger flat (122) is separated from underlying flat (120). By angling the conveyors (14, 16, and 18) in an upward direction, rearward gravitational force passenger flats (134 and 136) down conveyor (14). Halting the conveyors (202, 204, 206, 208, and 210) of the skew orientation station (20) can achieve forward gravitational separation of passenger flat (150). The skewed orientation of mail piece (200) is adjusted by selectively lifting the belts (202 and 206) and driving the belts (202 and 206) in opposite directions.

Growing community of inventors

Phoenixville, PA, United States of America

Eugene T Mullin