Abstract: A circuit for generating at least two periodic output signals having a phase relationship controllable between zero and 180 degrees as a function of a d.c. control signal as compared to a ramp signal. Also included is circuitry for controlling the phase relationship to be at substantially 180 degrees when the d.c. control signal is always greater than the ramp signal and to be at substantially zero degrees when the d.c. control signal is always less than the ramp signal.

Abstract: A modular V-belt sheave which, in a specific embodiment, has two end modules and a hub connected to at least one of the modules and may have one or more intermediate modules and the modules are secured together by a plurality of tying members extending through aligned holes in the modules, the members preferably consisting of cast metal, such as aluminum, with heads on the opposite ends of the elements. The members are cast into the aligned holes and, as the members cool, they contract, holding the modules firmly together. A hub may be used which preferably has a radial member seating between two of the modules and having a plurality of holes for alignment with the holes in the modules and for receiving the tying members so that the members will rigidly secure the modules to the radial member.

Abstract: A line protector for central office use comprises an elongated housing open at one side for receiving components and a cover for the opening. First and second surge arresters are coaxially positioned within the housing. First and second line terminals are respectively connected to the arresters as is a common ground terminal. The three terminals project from one end of the housing in the provision of coplanar flat pins for plug-in connection with a circuit board edge connector. Means including a test contact in the housing permits use of a test probe to test the lines while the protector is plugged into the connector. A shiftable insulator in the housing is used optionally to interrupt the inside lines at the line terminal pins.

Abstract: A motor protection circuit which generates a signal having a value proportional to the magnitude of the input current of the motor and a motor speed signal having a value proportional to the difference between the rated motor speed and the actual motor speed. The motor speed signal is multiplied by the input motor current proportional signal to derive a product signal. The product signal is summed with the input motor current proportional signal to derive a sum signal. The sum signal is compared with respect to a preset level to determine if it is greater than a preset level. If it is greater than a preset level, the sum signal is coupled to the input of a voltage controlled oscillator which generates an output signal having a value proportional to the magnitude of the sum signal. The output of the voltage controlled oscillator is counted in an up/down counter and an output is gated when the total count reaches a predetermined level.

Abstract: A control system primarily for variable speed drives having input and output sheaves with axially movable flanges and a belt interconnecting the sheaves, in which a fluid actuating mechanism moves the flange on the input sheave to vary the pitch thereof, and consequently, the output speed of the drive. A fan or other fluid pressure creating device, is driven by the output element of the drive and is connected to a control mechanism which is responsive to a condition sensing device for providing a pressure varying according to the condition to be maintained. The control mechanism is connected to a source of operating pressure and is regulated by the pressure from the pressure creating device and the condition sensing device for varying the pressure in the pressure actuating mechanism to vary the position of one of the movable flanges and thereby control the output speed of the drive.

Abstract: A clearance seal for rotating shafts adapted for use with pillow blocks and the like, in which a series of washers is disposed in a housing of U-shaped cross sectional configuration. The washers are of thin metal and are stacked in face-to-face contact with one another and held in the housing in firm contact by a resilient member such as a wave spring washer. Clearance is provided between the inside diameter of the sealing washers and an inner race, shaft or similar rotating element, and the washers are adapted to move radially relative to one another to adjust to shaft misalignment. The seal is so constructed and arranged that the bearing can be readily purged by the flow of grease through the clearance provided by the seal to provide optimum performance over an extended period of time without interference from contamination.

Abstract: A system for supplying uninterruptible d-c power to a load. When the system operates in its normal mode, d-c load power is provided by the combination of a rectifier and a power switch. The d-c output of the rectifier may be used by a d-c to d-c down converter to recharge and maintain a battery if a separately powered source is not available for that purpose. A d-c to d-c up converter provides a relatively high amplitude d-c voltage from the battery voltage. The amplitude of this voltage is lower than the amplitude of the d-c output of the rectifier in the normal mode. When the amplitude of the rectifier output falls below the d-c to d-c up converter output voltage, the system changes to its failure mode and the battery provides d-c power to the load. The operation of the down converter if it is included in the system is inhibited.

Abstract: A transfer compensation circuit for use in a standby A-C power system which compensates for the transient in system output voltage which occurs when the system transfers from the conventional A-C input voltage to the standby power system. The compensation is dependent on the total load on the system at the instant of transfer. The total load includes both the external load connected to the system load and the battery in the standby supply if the system normally functions to provide charging current to that battery.

Abstract: A line protector and associated termination structure comprises a module having printed circuit board wiring internally thereof and also as outwardly projecting contacts adapted for connection to a printed circuit board edge connector. An insulator is disposed against the printed circuit board and is slidable therealong and optionally serves to interrupt the tip in and ring in sides of the telephone line when it is desired to place the protector module in the so-called "detent" position. The protector module may be restored to its normal operating condition by retracting the insulator or by removing the module entirely from its position in the connector and then reinserting the module fully into the connector. This latter operation automatically slides the insulator to its non-detent position.

Abstract: A variable speed belt drive in which the axially moveable sheave flange is connected to the drive shaft by a flexible element which performs the function of transmitting the torque from the shaft to the axially moveable flange, and which defines a fluid pressure chamber for applying a variable pressure to the moveable flange for moving the flange axially on the shaft as the pressure in the chamber is varied by the operation of a control device. The flexible element may be an annular member having a generally U-shaped configuration with inwardly extending side walls, one of the side walls being connected to the flange and the other side wall being connected to a flange-like member rigidly mounted on the shaft. Passages are provided through the shaft to connect the chamber with a source of controlled pressure.

Abstract: A three-part hinge mechanism is disclosed as a concealed hinge with two of the parts being first and second mounting brackets interconnected by a link. The first mounting bracket has means for mounting on an enclosure and the second mounting bracket has means for mounting on a cover for the enclosure. The hinge is concealed and permits the cover to be lifted or translated directly away from the enclosure by a sliding connection within the hinge and then the sliding connection becomes also a pivotal connection so that the cover may be pivoted to one side. This permits a relatively deep cover to enclose components mounted within the enclosure and closely adjacent the walls of the cover. By the first translational movement, the cover will clear these components and then the cover may be pivoted to one side. Additionally, the hinge may be readily connected and disconnected so that the cover may be completely moved out of the way for access to the components within the enclosure.

Abstract: A force measuring device comprising a load receiving platform supported by a multiple bending parallelogram beam type load cell is provided with a plurality of electrical strain gages. Strain gage elements mounted on one of the beams are displaced toward one side of the beam and strain gage elements mounted on the other beam are displaced toward the other side of the other beam. An appropriate resistor network is connected to at least one strain gage on one or both of the beams to correct for either longitudinal or transverse displacement of the load on the platform. To correct for both transverse and longitudinal displacement of the load a resistor network is connected to each of three of the strain gages. Suitable procedures for determining the values of the resistor networks in combination with the above structure are included.

Abstract: A torque cam assembly for variable speed belt drives having a driven sheave with an axially slidable flange, in which a collar is mounted on the shaft of the sheave and has a plurality of cams thereon, and a cam follower structure having generally axially protruding members is mounted on the slidable flange of the sheave for cooperating with the cams on the collar. Wear elements are disposed on the members and are adapted to contact the cams on the collar. Two sets of cams may be used with the cams of one set facing in one direction and the cams of the other set facing in the opposite direction, and a pair of wear elements is provided on each of the members for engagement with the facing cams. Each wear element is provided with a distinct protrusion of a generally conical shape to provide the initial contact area with the respective cam surface, for creating substantially equal load sharing relationship between the various cams.

Abstract: A transistor having a selectively saturated emitter collector path is protected.The emitter collector voltage level is sensed as being greater than a predetermined level to indicate saturation as is the presence and absence of drive current to the base. In response to the transistor not being activated to saturation while the drive current is applied to the base, a fault indication is derived. In response to the fault being indicated, the transistor is prevented from conducting by decoupling a source of operating voltage and current from the emitter collector path and/or decoupling the drive current from the base.

Abstract: A method and apparatus for applying a reverse bias voltage to the base-emitter junction of a transistor, for turning off the transistor from a normal conduction state, or for connecting a relatively low impedance current path between the base and emitter electrodes for turning off the transistor from a fault conduction state.

Abstract: A variable speed drive having a pair of sheaves and a belt interconnecting the sheaves in which one of the flanges on at least one of the sheaves is mounted on an axially moveable hub and is adjustable toward and away from the other flange. The hub is mounted on a shaft, and a key interconnects the shaft and hub and prevents relative rotation between the shaft and hub. The bearing surface of the hub is provided with spaced axially disposed lubrication grooves, and the shaft contains an axial passage and radial ports through which lubrication is injected into the grooves in the hub. An annular lubrication groove interconnects the axial lubrication grooves and is provided with a port for relief of excess lubricating pressure. The flange ends of the axial grooves are closed by a seal disposed in the end of the bore in the hub at the inner end thereof.

Abstract: In one embodiment of the invention, a switching circuit is provided by connecting the main current paths of a plurality of relatively low voltage transistors in series for switching a relatively high level of voltage, with zener diodes being connected across the main current paths of each one of the transistors, the zeners having a breakdown voltage rating no greater than the inverse voltage rating of their respective transistor, and polarized for breaking down whenever the inverse voltage rating of the transistor is exceeded, the zener diodes also providing a voltage divider circuit for applying appropriate levels of bias voltage to the common connections between the transistors for ensuring the inverse voltage ratings of the transistors are not exceeded at times that the transistors are all turned off, or non-conductive.

Abstract: A combination coupling and sheave in a variable speed belt drive in which a variable pitch sheave has a fixed flange, an axially shiftable flange and a shaft connected to the drive motor by a flexible coupling with the hubs thereof secured to the motor and sheave shaft. The inventive concept includes mounting the coupling hub on the sheave shaft in a bearing of a pillow block at the end of the shaft and connecting the fixed flange of the sheave to the hub, so that the fixed flange is driven directly by the hub rather than solely by the shaft, and the slidable flange is driven through the shaft, thus creating split power paths between the flexible coupling and the fixed flange and between the coupling and the slidable flange through the sheave shaft, thereby reducing the load on the operating parts of the sheave.

Abstract: A high-power, solid-state switching circuit includes in a preferred embodiment a first switching device susceptible to damage from excessive peak power dissipation at times of turn-on and turn-off in switching high currents from a relatively high-voltage supply, the first switching device having its main current path connected in parallel with the main current path of a second switching device that is substantially less susceptible to such damage from excessive peak power dissipation, but which has a substantially higher impedance in its main current path than the first device when turned on, the devices complementing one another via the operation of said switching circuit for turning on the second device before the first device, thereby substantially lowering the voltage across the main current path of the first device, allowing the latter to be turned on and turned off with substantially reduced peak power dissipation via the snubbing effect of the second device, and the first device relative to the second

Abstract: A continuously operating standby A-C power system which uses a single loop responsive to the system's input and output A-C voltages, the voltage of the battery included in the standby portion of the supply and the amplitude and frequency of the input A-C voltage for controlling the phase relationship between the input and output voltages. When the input A-C voltage is acceptable in both amplitude and frequency, the loop is closed. When the voltage becomes unacceptable, the loop opens. When the voltage returns to acceptability after a period of nonacceptability, circuitry is included in the system for slowly closing the loop.