Abstract: The invention relates to thermostatic apparatus for controlling the heating fluid supply temperature in a central heating installation having at least two radiators in different rooms. With each room having a thermostat for controlling the radiators therein, the apparatus operates so that the most active thermostat is given priority in controlling the temperature of the heating fluid.

Abstract: The invention relates to a compressor of the type used in refrigeration systems. In these compressors the piston pin in the transversely extending piston bore is of lesser length than the diameter of the piston such that undesired chambers are formed at opposite ends of the pin. The stroke is normally of a length that the piston pin and these chambers intersect the lower edge of the cylinder. Gas trapped in these chambers expands rapidly with an undesired popping noise when fluid communication is established at the end of the down stroke between the chambers and the interior of the crankcase. Throttling passages are provided between these chambers and the interior of the crankcase to prevent pressure build-up in the chambers and the accompanying popping noise.

Abstract: The invention relates to a refrigerator type motor-compressor assembly. The housing includes inner and outer tubular shaped casings with the inner casing in which the motor and compressor units are mounted being resiliently mounted relative to the outer casing. The cylinder block is rotatable with the motor shaft with the cylinder thereof extending transversely relative to the shaft. A piston in the cylinder is actuated by a pin carried by an annularly shaped member which is rotatable about a stationary, cylindrically shaped track member. The track member is eccentrically disposed relative to the axis of the motor shaft. An antechamber is provided on an end wall of the inner casing to form an isolated chamber between the inner and outer casings. The antechamber is utilized to provide for the exhausting of pressurized gas from the rotatable cylinder block.

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 hydraulic control system for a vehicle steering system or the like. The system includes two hydraulic cylinders each having a piston and a piston rod extending through one end thereof with the rod side of each piston having a smaller pressure area than the opposite side thereof. The pistons are mechanically interconnected by their piston rods. Each of the cylinders has first and second ports respectively at the nonpiston and piston ends thereof. There is a source of fluid pressure and an exhaust tank and a separate valve unit for each of the cylinders. A valve operating unit includes a steering wheel for operating the valve units in unison. The valve units have passages arranged so that for turning in either direction the first and second ports of one cylinder and the second port of the other cylinder are connected to the pressure source. At the same time the first port of the other cylinder is connected to said exhaust tank.

Abstract: The invention relates to a pressure responsive electric switching device of the type in which a switch actuating element is oppositely loaded by pressure influenced operating element and an adjustable spring. The switch actuating element is mounted in a sheet metal carrier and the switch to be actuated is mounted in an insulated housing. The connection between the carrier and the housing involves the cutting of the carrier sidewalls in a manner to form lugs and the providing of grooves in the insulated housing for receiving the lugs. The carrier sidewalls also have cut-outs formed in a manner to economically provide knife-bearings for pivotally mounted elements of the switching device.

Abstract: The invention relates to controls for a refrigeration assembly of the type having freezer and utility compartments with the freezer compartment having the greater cold requirement. The compartment evaporators are in parallel fluid flow lines with an electrically operated blocking device such as a PTC resistor being in the utility compartment line. Thermostats in the two compartments control the flow of refrigerant to the two compartments in a manner such that at the beginning and end of a cycle both compartments are supplied with refrigerant fluid while during the middle part of the cycle only the freezer compartment is supplied with refrigerant fluid.

Abstract: The invention relates to an electric motor and piston type compressor unit used for small refrigerators. The housing or cylinder of the compressor is attached to the motor casing and these two members, as a unit, are resiliently mounted in a sealed housing. In order to minimize the overall size of the unit, and specifically the outer housing, the piston connecting rod has a special shape at its crank end to facilitate the initial installation of the piston and connecting rod. The crank end of the connecting rod has a larger bore than the crankpin and the shape of the crank end is characterized by a recess which allows the crank end to clear the crankpin while being moved into surrounding relation to the crankpin after which a sleeve is installed between the crank end and the crankpin. The recess is strategically located so that while it facilitates the assembly operation there is no compromise or sacrifice with regard to the maximum loads the connecting rod can withstand.

Abstract: The invention relates to a refrigeration assembly and particularly to defrosting apparatus therefor. The assembly includes a bellows operated thermostatic motor switch responsive to evaporator temperatures for operating the compressor motor. After a predetermined number of operating cycles of the compressor the defrost apparatus is actuated. There is a linkage between the bellows and the motor switch with a main spring acting thereon to oppose the bellows and a differential spring acting thereon to assist the bellows. The differential spring is made inoperative by the defrosting unit during the defrost setting. The main spring and the differential spring are calibrated so that when both springs are effective the motor switch is actuated at a predetermined evaporator temperature. When only the main spring is effective during the defrost setting the motor switch is actuatable at an evaporator temperature higher than the above referred to temperature.

Abstract: The invention relates to a control circuit for a brushless self-starting D.C. motor of the type having a permanent magnet rotor and stator coils, a magnetic field-dependent component or sensing coil for sensing the position of the rotor, and controllable electronic switches in respective series with the stator coils and the D.C. source. The switches control current through the stator coils in dependence on the rotary position of the rotor pursuant to magnetic field dependent parameter changes in the sensing coil. The control circuit is characterized by including an oscillator with an LC resonance circuit of which the inductance is formed by the sensing coil. The circuit includes a modulator for modulating the oscillation of the oscillator in response to the induction changes brought about in the sensing coil. The control signals for the switches are derived from the modulated oscillator oscillation because the oscillator frequency is considerably higher than the rotor speed.

Abstract: The invention relates to an inverter circuit which includes at least one pair of series connected transistors. The transistors of each pair are switched alternately on and off with a short dead period therebetween to prevent short circuiting. Rapid switching is accompanied by power being converted in each transistor on being switched off which is harmful to the transistor. Known auxiliary circuits disposed respectively parallel with the transistors include capacitors to slow the rise of the collector voltage relative to the drop in emitter current and this provides some protection against damage. Additional protection is attained by providing a choke coil in series with each pair of transistors which retards the charging of the capacitors and the transistor charging current is thereby kept low to prevent or minimize transistor damage.

Abstract: The invention relates to an encapsulated refrigerator assembly of the type in which an integrated motor and compressor unit is resiliently mounted in a hermetically sealed casing or capsule. An oil sump at the bottom of the capsule is provided for lubricating oil. An externally disposed centrifugal separator with an oil collecting tank at the bottom thereof provides refrigerant in vapor form for the compressor and oil for the oil sump. The compressor has an inlet for receiving refrigerant vapor from the separator and the capsule has a single port connected to the separator. A connecting pipe inside the capsule provides fluid communication between the capsule port and the inlet of the compressor. Universal joint fittings at opposite ends of the connecting pipe allow for relative movement between the resiliently mounted motor compressor unit in the capsule and the relatively stationary capsule walls.

Abstract: The invention relates to ultrasonic apparatus for measuring flow quantities and related parameters of a liquid flowing with a free surface in a channel. Two transducers are provided with one being mounted in the channel below the level of the flowing liquid. The other transducer is mounted on a float member which is floatable on the surface of the liquid. The transducers are effectively positioned from each other and a measuring path is formed therebetween which has components in the vertical direction and in the direction of flow. There is a measuring circuit for determining the transit times of the ultrasonic waves in both directions and an evaluating circuit for determining the desired quantities with regard to the transit times.

Abstract: The invention relates to ultrasonic apparatus for measuring flow quantities and related parameters of a liquid flowing with a free surface in a channel. Two transducers are mounted in longitudinally spaced relation to each other in the channel and below the level of the flowing liquid. The transducers are positioned and directed so that the effective measuring path therebetween is reflected from the underside of the liquid surface level and has components in the vertical direction and in the direction of flow. There is a measuring circuit for determining the transit times of the ultrasonic waves in both directions and an evaluating circuit for determining the desired quantities with regard to the transit times.

Abstract: The invention relates to a vehicle steering control device of the type having a housing, inner and outer rotary slide members disposed in a bore of the housing and forming a reversing switch. The housing has inlet and outlet ports and two motor ports. Four axially adjacent spaced grooves being in the interface between the bore of the housing and the outer rotary slide member with the first and fourth grooves being connected to the inlet and outlet ports and second and third grooves being connected to the two motor ports. A steering shaft is connectable to the inner rotary slide member and a measuring motor which, on actuation of the control device, is connected to the inlet port to cause the outer rotary slide member to follow the inner rotary slide member.

Abstract: The disclosure relates to a thermostatic expansion valve for refrigeration plants, particularly with an air-cooled condenser, comprising an operating element which is loaded in the opening direction against the force of a spring by a pressure dependent on the superbeating temperature of the evaporator and possibly relieved by the evaporator pressure, and comprising a closure member which is adjustable by the operating element and co-operates with a seat.

Abstract: The invention relates to an inverter circuit for operating an asynchronous motor having an adjustable speed. The inverter has its output frequency regulatable by a frequency regulator and the D.C. supply has its voltage regulatable by a voltage regulator. There is a desired value frequency regulator having a signal (f) and voltage and current measuring devices having output signals (E) and (I). A control circuit processes these signals (f, E, I) to form input values for the referred to voltage and frequency regulators. The control circuit includes a computer circuit which, from at least two output values and at least one constant, calculates a computed value of the third output value which, together with the first-mentioned output values, given by way of computation a substantially constant slip frequency for a given desired value, and this computed value is compared with a value substantially corresponding to the actual third output value.

Abstract: The invention relates to a power steering system of the metering type. Units of this type most commonly utilize gerotor type gear sets for the metering operation. During emergency operation when pressurized operating fluid is not available from a pump, steering is accomplished by operating the metering motor with the steering wheel which provides a pumping function for manually creating pressurized fluid. A problem with this type of unit is that a substantial amount of manual exertion is required to steer the vehicle under these conditions. Control units of this type have a universal drive between the rotatable valve thereof and the inner gerotor gear which has a combination rotating and orbiting movement. In this invention the universal drive has two main sections with a lost motion emergency device between the opposite ends.

Abstract: The invention relates to a DC control circuit for controlling the speed and rotary direction of a three-phase asynchronous motor. The circuit has an inverter section having three branches with a pair of switch elements in series in each of the branches. The inverter section has a common extinguishing switch element in shunt with the three branches. A speed determining frequency generator is responsive to the voltage of the DC supply and an ignition signal generator for operating the inverter switch elements is driven by the frequency generator. An extinction signal generator for operating the common extinguishing switch element is also driven by the frequency generator. A reversing circuit section between the ignition signal generator and the inverter branches has two states for exchanging the control lines of the inverter switch elements in at least two of the branches.

Abstract: The invention relates to a circuit for determining the arrival time of an ultrasonic signal. The circuit includes a differentiator for transforming an ultrasonic signal to a substantially linearly increasing signal, and a threshold value detector for transforming the linearly increasing signal to an arrival delay signal. A phase detector in the form of a D-type flip-flop determines the phase position of the arrival delay signal relative to a reference signal. The phase detector generates early signals on early arrival of the delay signal and late signals on late arrival of the delay signal. A regulator integrator is provided between the phase detector and the differentiator for producing an output voltage for altering the delay period of the arrival delay signal responsive to the phase position of the delay signal.