Abstract: The invention relates to an expansible chamber rotary piston engine of the type having meshing internal and external gears wherein one rotatable gear, which may be an internal gear or an external gear, has rotatable and oribtal movement relative to the other gear which is fixed relative to the housing. The engine has relatively rotatable and cooperable valve members connected respectively to the gears. The cooperable surfaces between the valve members may be either flat or cylindrically shaped. The valve members have respective first and second sets of circumferentially arranged ports with each port in one set moving sequentially into alignment with each port in the other set during relative rotation of the valve members. The ports are generally rectangularly shaped to provide maximum flow capacity between the valve members.

Abstract: The invention relates to a backstop ring for a stuffing box or the like which is cooperable with a carbon sealing ring. The main parts of a stuffing box are normally the stationary backstop ring and the carbon slide ring which rotates with the shaft. These two rings have mutually engaging sealing surfaces. The sealing surface of the stationary backstop ring is ground in a manner to form scratches which are orientated to create a radially outward pumping effect. The flatness of the ground surface has an overall variation of less than six microns and preferably is between 2 and 5 microns. The scratches have a roughness between 0.2 and 2 microns. For scratches on the order of 1 to 2 microns the surface is phosphatized.

Abstract: The invention relates to a protective circuit for an inverter having semiconductor control elements. The protective circuit includes a series regulator in its inlet branch and an intermediate filter circuit with the capacitor thereof extending between the inlet and outlet branches. First and second signal generators control the series regulator and the inverter. A control unit controls the first signal generator for normal operation. Parallel comparator units have monitoring inputs connected to different parts of the protective circuit for detecting abnormal conditions and outputs connected to both of the signal generators to effect the immediate turning off of the series regulator and the inverter when abnormal conditions are sensed. The inverter is off concurrently with the comparator output signal but a multivibrator switch having a predetermined period causes the series regulator to be off during that whole period independently of the comparator output signal.

Abstract: An electric storage heater assembly which includes a core and a resistance heater for the core. A charging switch is in series with the resistance heater and an electric comparator for operating the switch has two inputs connected to first and second controls which are responsive to the instantaneous temperature of the core and the final temperature of the core for the preceding charging period. The first comparator input is also connected to auxiliary controls which sense indoor and outdoor temperatures and provide signals which are summed with the signal which represents the core temperature.

Abstract: The invention relates to a control circuit for a self-starting electric motor of the type having stator windings in respective series relation with gate type electronic switches which are controlled by control impulses generated in a gate circuit. A motor starting pulse generator is connected to the gate circuit which generates short starting pulses and long blocking pulses. Motor operating controls responsive to commutation impulses are connected to the gate circuit which override the effects of the motor starting pulse generator during normal operation. An integrator for the commutation pulses generates a voltage level signal which corresponds to the speed of the motor. A comparator compares this signal with a reference voltage and, when the signal reaches a predetermined level, the motor starting generator is overriden. When the motor is stopped for any reason the short starting pulses attempt to start the motor at intervals determined by the length of the blocking signals.

Abstract: The present invention relates to a compressor refrigeration plant comprising a throttling device between the condenser and evaporator and, associated with the throttling device, an intermittently operable electric heating resistor, a chamber being disposed upstream of at least a part of the throttling device and the electric heating resistor being a PTC resistor which is arranged in the chamber and which, when a temperature range between the evaporating temperature of the refrigerant associated with the pressure in the chamber and the coking temperature of the refrigerant oil is exceeded, goes over from a low to a high resistance.

Abstract: The invention relates to a method and apparatus for controlling a three-phase inverted rectifier. In this method each half wave is divided into six intervals with the third and fourth intervals forming a first zone with a constant voltage level, the second and fifth intervals forming a second zone with impulses of varying width, and the first and sixth intervals forming a third zone with impulses of varying width narrower than the impulses in the second zone. The narrower and wider impulses are treated similarly with regard to their number and have a constant width ratio as the result of a factor X. The center spacings of the narrower and wider impulses are equal. The number of impulses in each of the zones two and three is n. When n is 1.5, X should be about 0.78.

Abstract: The invention relates to a piston assembly for compressor and the method of making the assembly. A piston body is molded with spaced apart downwardly open grooves formed with concave semicylindrically shaped summits and parallel side walls. The summits and sidewalls are formed with pimples. A connecting rod pin having a connecting rod attached thereto is press fitted into the grooves. The pimples may serve as weld pimples by being softened by a welding current. The pimples on the sidewalls may alternatively be mechanically swaged to press inwardly against the rod to hold it in its installed position.

Abstract: The invention relates to a control circuit for a brushless self-starting D.C. motor of the type which has a permanent magnet rotor and a stator coil, a magnetic field-dependent component subjected to the rotor field to determine the rotary position, and a controllable electronic servo-element lying in series with the stator coil at the D.C. source, the servo-element controlling the flux through the stator coil in dependence on the rotary position of the rotor, the magnetic field-dependent parameter changes of the magnetic field-dependent component being convertible to a control signal for the servo-element. The control circuit is characterized by including an oscillator with an LC resonance circuit of which the inductance is formed by the magnetic field-dependent component in the form of a sensing coil (10) with a core. The circuit includes a modulator for modulating the oscillation of the oscillator in response to the induction brought about in the sensing coil by the torot field.

Abstract: The invention relates to a spring brake assembly of the compressed air type for truck tractor types of vehicles. The brake actuators of the assembly each includes a heavy coil type emergency spring which is held in a compressed state on the back side of a diaphragm by compressed air applied to the front side of the diaphragm during operation of the vehicle. The emergency spring expands to actuate a brake setting push rod when the compressed air is vented from the front side of the diaphragm and this occurs when the vehicle engine is turned off or when there is an accidental loss of compressed air from the brake unit. The emergency spring is housed in a chamber and, due to the movement of the diaphragm, atmospheric air is continually being drawn into and expelled from that chamber. As the brake actuators are mounted on the rear axle of the vehicle, they are in low positions relative to the roadway and the air drawn into the emergency spring chambers thereof is laddened with salt and water.

Abstract: The invention relates to a method and apparatus for controlling an inverted rectifier having a constant DC supply voltage and adjustable frequency and amplitude of the fundamental oscillation of the output voltage. The rectifier is for an AC motor and the phase voltage is at least partly formed by width-modulated pulses and the voltage-time area of the pulse series is increased to eliminate an inadequate pulse spacing. Switching elements in the rectifier require a certain switching time and care must thus be taken to ensure that certain minimum pulse widths or pulse spacings must be observed to avoid short circuiting in the rectifier. Also to be avoided is pulse bridging which leads to a sudden increase in the voltage-time area and thus to a leap in the amplitude of the fundamental oscillation of the output voltage. The effects of this, e.g. in the magnetization of a connected motor, are undesirable.

Abstract: The invention relates to a temperature control system for refrigeration unit. In this system a capillary tube extends between the condenser and the evaporator and a chamber upstream from at least a section of the capillary tube contains a PTC resistor. The PTC resistor is supplied with current in response to a thermostatic sensing of a predetermined low temperature in the room or compartment which contains the evaporator. In response thereto the PTC resistor generates enough heat to produce a vapor plug which throttles of stops the flow of refrigerant in the capillary section but not enough heat to cause coking of the refrigerant oil which would permanently plug the capillary tube. The downstream capillary section is so dimensioned that it is permeable to liquid refrigerant but is substantially impermeable to the refrigerant vapor generated in the chamber.

Abstract: The invention relates to an electric switch assembly of the type operated by a thermostatic bellows, for use on refrigerators. The operating bellows is part of a system having a liquid/vapor filling and the movement of the bellows operates a microswitch. A hinged arm which operates the microswitch is biased in a switch closing direction by the bellows and in a switch opening direction by a spring system which includes a main spring and a differential spring in series. The force displacement line of the spring system approximates the force displacement line of the bellows and has two segments with different slopes. The two segments are formed by arresting the movement of the differential spring to make it ineffective at an intermediate point in the displacement of the bellows. The first segment with a lesser slope represents the action of both springs in series while the other segment, of greater slope, represents only the main spring.

Abstract: This invention relates to a snap action type of switch in which a generally G-shaped sheet metal strip has a fixed terminus and a movable terminus forming an inwardly and upwardly extending arm which is pivotally mounted in a knife bearing. The midportion of the strip extends between fixed contacts and has a contact thereon which alternately engages the fixed contacts. An actuator is movable transversely of the strip and engages the arm of the strip to move the movable contact in the opposite direction relative to the movement of the actuator.

Abstract: The invention relates to a control circuit for a servomotor of the type having a piston displaceable to selectable positions in one direction by an expansible substance heatable by an electric heating element and in the other direction by a return spring. The circuit includes a pulsating power supply and a control switch and a thermostatic unit for generating a temperature responsive control voltage. A potentiometer for generating voltages corresponding to different positions of the piston is operably connected to the piston. A comparator for comparing the control voltage with the potentiometer voltage generates a go-no go signal which is relayed to the heating element control switch. Upper and lower limit switches are associated with the selectable positions of the piston. The limit switches selectively override the potentiometer to effect operation of the heating element control switch. Light emitting diodes are provided which give visual indications of the heating and cooling cycles.

Abstract: The invention relates to a cut-off valve assembly for an oil burner assembly. The cut-off valve is of the type which is spring biased and rapidly opens and closes above and below a predetermined pump pressure. The rapid closing is to prevent fuel oil from dripping from the nozzle. The valve assembly has an expansible chamber formed with a diaphragm. The chamber has inlet and outlet ports with a valve seat formed on the outlet port. A spring biased adjustment element has a disk shaped portion below the diaphragm which carries a closure member for the outlet port. The face of the closure member is displaceable relative to the disk shaped portion and is of a larger diameter than the diameter of the valve seat for the outlet port.

Abstract: The invention relates to a control unit for an inverted rectifier of the type having a constant DC voltage supply and a frequency settable by a frequency control signal. The main feature of the control unit relative to the invention hereof is the monitoring of the critical pulse spacings of the pulse generator output without the use of time-dependent elements. The control unit includes a voltage controlled oscillator for generating a triangular wave form controlled by a frequency control voltage. A variable width pulse generator is fed by the triangular wave form and is controlled by a pulse width control voltage. The control unit includes an analog computer for generating internally thereof a function which corresponds to the spacing of the pulses of the pulse generator. The computer includes an amplifier having a noninverting input for receiving a control signal which corresponds to the amplitude of the triangular wave form.

Abstract: The invention relates to a hydraulic control unit for a servomotor of the type used for vehicle steering systems. The unit has a control circuit with a power operated pump and a hand operated metering motor and an operating circuit with a power operated pump. The two circuits intersect upstream from the servomotor. A pressure comparison, throttling and proportioning valve is disposed between the outlets of the two pumps of the control and operating circuits. The proportioning valve is controlled by a differential pressure applied by the pumps and a spring which supplements the operating pump pressure. In the normal operating mode the proportioning valve allows a minor fractional flow of the pressurized fluid generated by the control pump to flow through the valve to the operating circuit.

Abstract: The invention relates to a hydraulic regulator of a type which may be operated by electromagnetic switching valves. The assembly includes a piston and cylinder arrangement with position setting chambers at opposite ends thereof of larger diameter than the servo piston. Movable abutment elements in the chambers of larger diameter than the servo piston are biased by centering springs. There are parallel circuit branches in which the end chambers are disposed and switching valves are in these branches. The actuating of one of the valves to block its branch raises the pressure in the end chamber in that branch causing the piston to move in the other direction so as to move away from the biasing force of one spring biased element and engage the biasing force of the other spring biased element. When the other switching valve is actuated to block its branch to stop the piston in a desired position, the fluid pressure in the end chambers is equal.

Abstract: The invention relates to a hydraulic regulator of a type which may be operated by electromagnetic switching valves. The assembly includes a piston and cylinder arrangement with position setting chambers at opposite ends thereof of larger diameter than the servo piston. Movable abutment elements in the chambers of larger diameter than the servo piston are biased by centering springs. There are parallel circuit branches in which the end chambers are disposed and switching valves are in these branches. The actuating of one of the valves to block its branch lower the pressure in the end chamber in that branch causing the piston to move towards the blocked branch so as to move away from the biasing force of the opposite spring biased element and engage the biasing force of the adjacent spring biased element. When the other switching valve is actuated to block its branch to stop the piston in a desired position, the fluid pressure in the end chambers is equal.