Abstract: The invention relates to a servo assembly having a stationary part including a housing, a movable member and a servo motor. Of primary interest is the stopping mechanism which includes a stop unit on the movable member and two pressure operated, vertically reciprocal stop members mounted in the housing. Two hydraulic circuits are provided with a first circuit for the two stop members and the second circuit for the servo motor. Throttle valving for the first circuit is provided between the two stop members and the housing. Prior to reaching a stopping position the stop unit on the movable member actuates a switch which relieves the pressure in the first circuit and causes one of the stop members to descend to an intermediate position where throttling occurs and the other stop member to descend to a final position where throttling may or may not occur. The throttling causes substantial braking of the movable member during a short distance of travel just prior to the stopping position being reached.

Abstract: The invention relates to a thermostatic control unit for radiator valves, this unit being of the type which has an adjustable bellows. The bellows is adjusted only during initial calibration of the thermostatic control unit or when the temperature setting of the unit is changed. The control unit includes a screw and nut arrangement in which the nut is attached to the free or moving end of the adjustment bellows. About three turns between the screw and the nut have been found suitable to provide a sufficient movement of the nut to allow an adequate adjustment of the bellows. A problem with prior units of this type is that if the screw is turned inwardly more than three turns the thread may bottom and thereby cause an excessive and damaging torque to be transmitted to the bellows. Alternately, if the screw is turned outwardly to disengage from the nut, the nut becomes cocked in the enclosed casing and it becomes impossible for the screw to re-enter the nut.

Abstract: The invention relates to a hydraulic steering apparatus comprising a continuously operating pump, an operating motor for controlling the parts to be steered, a control device which is adjustable by the steering wheel and which, in its neutral position, connects the pump to a tank through a short-circuiting path. The control device has two operating positions in which the pump is connected to one side or the other of the operating motor and connects the other side of the operating motor to the tank. The control device has a control element connected to a steering wheel and a following element connected to a metering motor and these elements are relatively displaceable to a limited extent. Apparatus is provided to prevent the steering parts moved by the operating motor from stroking mechanical abutments.

Abstract: The invention relates to a hydraulic control apparatus of the type used in vehicle steering systems. In all such systems there is a reversible type hydraulic motor connected to the steering linkage. The motor has complementary expansible chambers. With the use of control means pressurized fluid is selectively delivered to one chamber which is caused to expand concomitantly with the collapsing of the other chamber from which fluid is returned to a sump. Forces transmitted to the hydraulic motor through the steering linkage by reason of the wheels striking objects such as stones or curbs cause an objectionable effect by reason of fluid being forced out of the motor back into the system. This effect is avoided by providing two valve assemblies for the two ports of the reversible motor which function in the absence of a steering command as ordinary one way check valves which prevent the undesired flow of fluid from either of the motor ports.

Abstract: The amplification of periodic or aperiodic pulses is varied by envelope detecting the received pulses and passing the resulting envelope waveform to a latching comparator which, when enabled, provides an output pulse whenever the input waveform has an amplitude which exceeds a predetermined value. An itegrator coupled to the output of the comparator is continuously operative to increase or decrease the gain of the amplifier according to the absence or presence respectively of the output comparator pulse. In this manner the amplitude of signals or pulses is automatically controlled despite circuit and transmission vagaries.

Abstract: The invention relates to a gerotor type of rotary piston machine which is operable as either a pump or a motor. In this type of device an externally toothed rotor member is eccentrically offset relative to an internally toothed stator member and in operation these members mesh to form expanding and contracting cells on opposite sides of the line of eccentricity. There is shaft means for driving the rotor and a distributing valve for feeding and exhausting the cells is attached to the shaft means. In order to compensate for torsion stresses in the shaft means which would cause the distributing valve to be slightly out of phase relative to the rotor the connection between the valve and the shaft means is made adjustable in response to sensing means which sense the pressure conditions in the gerotor when the rotor is symmetrical relative to the line of eccentricity.

Abstract: An air conditioning system comprising a room to which conditioned air having temperature and volume parameters is delivered. Temperature sensing means is provided for sensing the temperature of the air in the room. Air supply means responsive to the sensing means is provided in an air supply duct. Damper means is also mounted in the duct for varying the effective area of the opening of the duct. A regulating means is provided for controlling the damper to vary the air velocity in accordance with a constant value for the expression Ar.1.sup.-.sup.3/2, where Ar is the Archimedean number, and 1 represents the effective area of the opening. The temperature sensing means also controls the volume parameter of the air supply which air supply has a constant temperature parameter.

Abstract: The invention relates to a hydraulic steering unit for automotive vehicles. A main feature of the unit is that pressure relief means are provided for relieving excessively high pressures developed in the unit which are caused by the steered wheels encountering road obstacles. The unit includes a pump, a drain tank and a working motor which is connectable to the wheels to be steered. The working motor has complementary expansible chamber means and a control valve is connected to the motor with a pair of supply and exhaust conduits which are selectively connectable to the pump and the tank by the control valve. A shunt line is provided between the pump and the tank and a pressure relief valve is in the shunt line. A manually operated valve controlled by a steering wheel is connected to the pump and the drain tank. A pair of control lines are connected to the manually operated valve which are selectively connectable to the pump and the drain tank by the manually operated valve.

Abstract: The invention relates to an electrical junction box for use with snap-in type printed circuit board modules. The junction box is connected to some form of electrical apparatus such as an electrical motor. The junction box has terminals to which conductors from the electrical apparatus such as a motor can be clamped. The junction box has a slot with the terminals in alignment on one wall thereof. The slot receives a circuit board module which has contacts which are arranged to respectively engage the terminals in the slot.

Abstract: A control circuit for controlling a supply of D.C. voltage to the input of an inverter. The circuit includes a control arrangement and apparatus for adjusting the D.C. voltage supply in accordance with signals applied to the control arrangement. The circuit also includes a current sensor for sensing the current supplied to the inverter, a sensing device for an A.C. voltage component connected across the input to the inverter, and apparatus for applying signals to the control arrangement in accordance with the current sensed by the sensor and the A.C. voltage component sensed by the sensing device.

Abstract: A method for making a heavy duty PTC resistor with a pressed and sintered hollow cylindrical body of a ceramic composition which has two end faces in a radial plane with a connection contact on each end face.

Abstract: Ultrasonic signals are transmitted alternately upstream and downstream in a fluent media. A reference signal timed to occur at the estimated time of arrival of the alternate signals is used to ascertain whether the actual signals arrive earlier or later than the reference signal. Control circuitry responsive to the early and late signals generates two signal levels associated with transmission direction which adjusts the time position of the reference signal until it coincides with the actual arrival times. One signal level is related to flow velocity. The other signal level is related to sound velocity in the fluent media.

Abstract: A heating regulator which is responsive to effective outdoor temperatures and the temperature of a heated fluid supplied by a boiler. The regulator has an adjustably positionable pointer which represents a characteristic curve. The regulator includes three slide members with the pointer being pivotally mounted on one of the slide members for a translatory movement therewith and pivotal movement relative thereto. Two potentiometers are operated by two of the slide members and one of the slide members actuates the third slide member which in turn effects pivotal movement of the pointer.

Abstract: The invention relates to a furnace type air throttle assembly which operates in a manner to supply a constant volume of air per unit time. This is done with a bellows and throttle arrangement in which (1) the total pressure at the inlet, which is the sum of the dynamic and static pressure, is utilized to expand the bellows and move the throttle in a closing direction and (2) static pressure and weight means are utilized to compress the bellows and move the throttle in the opening direction.

Abstract: The invention relates to a control valve assembly for a hydrostatic control system such as power steering assembly. A common control valve assembly of this type has relatively rotatable inner and outer elements connected respectively to a vehicle steering wheel and a servomotor. Paired holes in the inner and outer element permit the flow of fluid therethrough when the unit is in its neutral position with the paired holes in respective registration. In hydrostatic steering system of this type impact is sometimes applied to the steering wheel when the working motor connected to the steered wheels is suddenly loaded, e.g. when the wheels strike a stone. Such impacts on the steering wheel are avoided by providing a one-way valve in a section of the working path through which fluid flows to the working motor. Pressure regulating valve means, excess pressure valve means and emergency control valve means are associated with the one-way valve assembly.

Abstract: An electric storage heater assembly which is charged at night when energy rates are low and utilized during the day when the rates are higher. A fan unit is controlled by a thermostat to extract heat from the heater assembly. The previous days experience relative to the total time the fan operates is a measure of the heat to be stored during the off hours. An integrator with input and output switching elements activated by a clock controlled time switch is used in connection with a three position room thermostat, the positions being for high and low temperatures and neutral. The input switching element has positive and negative terminals and during day operation, the time the thermostat is in its low temperature position is summed through the positive terminal. The time the thermostat is in its high temperature position is subtracted from the accumulated value of the integrator through the negative terminal.

Abstract: The invention relates to a magnetic valve assembly of the type in which an energized armature moves a valve closure member to an open position and a load spring in compression maintains the valve closure member closed when the armature is nonenergized. Relative movement between the armature member and the closure member is provided and an energy storing spring between these members resists the relative movement. In two embodiments the energy storing spring is stressed in compression in one and in tension in the other. The valve closure member does not begin to move until the armature causes the energy storing spring to be stressed to an extent equal to a predetermined stressing of the load spring. With this mode of operation the armature stroke is longer than the stroke of the closure member and this results in a smaller magnetic system being sufficient for a given valve system.

Abstract: The invention relates to a radial piston type pump comprising a casing, a shaft, two or more piston carriers mounted on and driven by the shaft, and a curved track surrounding the piston carriers. The piston carriers are axially movable on the shaft and pressure chamber and scaling means are provided between adjacent carriers to bias them in opposite directions against the internal casing walls which form a chamber in which the carriers are rotatably mounted. Fluid inlet and outlet means in one of these casing walls has fluid communication with the inlet and outlet passages in the carriers and the biasing of a carrier against this wall serves to provide sealing between the relatively rotating surfaces to minimize the leaking of fluid between these surfaces.

Abstract: A heavy duty PTC resistor with a pressed and sintered hollow cylindrical body of a ceramic composition which has two end faces in a radial plane with a connection contact on each end face.A heavy duty PTC resistor sintered body of a ceramic composition which has two end-faces carrying a connection contact; the invention also concerns a method of manufacturing such PTC-resistor.High duty PTC-resistors are required for some purposes. If for example a PTC-resistor is used as a starting device for a single-phase motor, it has to be designed to deal with almost the entire mains voltage and to carry power of 500 W or more. The usual cylindrical bodies, provided at their two end-faces with connection contacts, frequently exhibit cracks under loads of this kind.A high-duty PTC-resistor is thus known (German Patent Specification OS 1 465 349) which is made up of a stack of solid or hollow flat cylindrical discs, the end-faces of the superposed discs being interconncted by a contact layer.

Abstract: The invention relates to an electrical resistor with a SiC body, particularly for ignition or heating purposes, and to a method of producing such electrical resistor.