Abstract: A controller for a climate control system has a humidity (wet-bulb or dew point) temperature sensor as well as a dry-bulb temperature sensor within the enclosure. The humidity temperature value is used in connection with the dry-bulb temperature to generate a single error signal which is a function of both the dry-bulb and the humidity temperature values. This permits control of both enclosure temperature and enclosure humidity without abnormal cycling of the climate control system. Instead of using a sensor which directly measures the humidity temperature, the humidity temperature can be synthesized from the relative humidity and dry-bulb temperature within the enclosure.

Abstract: A humidity control system for a space receiving conditioned air from a duct has sensors which measure the current humidity in both the space and the duct. The system calculates a duct set point based on the difference between the current space humidity and the humidity set point for the space. The system then controls the humidity of the air passing through the duct so as to both minimize the difference between the space humidity and the humidity set point for the space and to prevent the air in the duct from reaching its dew point. A special algorithm is used to compensate for lag in the duct's humidity sensor.

Abstract: A decorative article of manufacture has a penetrable core into which the ends of sprigs are inserted. Leaves forming the ends of the sprigs preferably conceal the core completely. The sprigs include preserved leaves on the unsupported projecting ends which define an approximate geometric shape. The sprigs have their natural leaves on their unsupported ends and are preferably form of preserved eucalyptus The core is preferably formed of a rigid plastic foam. The geometric shape defined by the sprigs' ends may have for example a conical, semi-conical, toroidal, or spherical shape.

Abstract: A circuit for measuring a parameter value by measuring the time required to charge a capacitor in a sensor RC circuit from a first to a second voltage includes a reference RC circuit whose capacitor is also charged between two voltage levels. The circuit is calibrated so that the time interval required to charge the reference capacitor may be used to improve the accuracy with which the parameter value is measured.

Abstract: An electrical switch assembly includes a snap action switch which is actuated from one to another conduction state by a snap action interface mechanism moved by an external actuation element between first and second corresponding positions. The snap action interface mechanism prevents the snap action switch from operating improperly when the external actuation element is of the type which provides a slowly moving, low actuation force. A preferred embodiment has as a part of the interface mechanism, a lever having a ferromagnetic portion which snaps between the first and second positions under the influence of at least one magnet. The switch assembly is particularly suitable for actuation by the bimetal coil strip which commonly forms the temperature responsive element in a thermostat.

Abstract: Apparatus and method for sensing the operating condition of a burner temperature as the indicating variable. When the operating status is stable, the flue temperature should be nearly identical to that when the system was known to be in proper condition. During a time when the system is known to be in proper operating condition, the flue temperature is recorded during stable operation for a number of different firing rates. When identical or similar firing rates occur at a later time and operation is stable, the operating flue temperature is compared with the current flue temperature, and if substantially different, an operation status signal is set to a state indicating this change in operating condition.

Abstract: A burner control system periodically tests for and detects an out of range signal level from a flame sensor in the burner. When the system is in standby operation where no flame is present, the control system checks whether the flame signal level is within an abnormal range defined by a low margin level and a threshold level. When the system is in an operational phase where flame is expected, the system checks whether the flame signal level is within an abnormal range defined by a high margin level and the threshold level. Should either check detect the flame signal within an abnormal range, a signal is provided indicating this abnormal condition. Preferably, the abnormal condition is used to control the flashing of an indicator light, fast during standby phase if the flame signal level is too close to the threshold level and more slowly if the flame signal level is too close to the threshold level while flame is present. It is also possible to use two different lights for the indicators.

Abstract: An actuator of the type having a limit switch for setting the range through which the actuator's output element moves, has a first element fixed to the output element and a second element carrying an actuation element for tripping the limit switch. Tripping the limit switch during movement of the output element stops movement at that position. A detent mechanism shared by the first and second elements maintains the current position between the first and second elements until force is applied to the second element to overcome the resisting detent force and shift the second element relative to the first element. By so shifting the second element, the position of the actuator's output element is changed to thereby change the position of the output element at which the limit switch is tripped and thereby the range of motion for the output element.

Abstract: A converter circuit provides an output signal of polarity opposite that of an input signal having a DC component and a low frequency periodic component in response to presence of that input signal. Current is transferred from a first capacitor to a second to accomplish this conversion. The circuit has particular application in a flame sensing interface circuit using a sensor of the infrared radiation generated by the flame to change the impedance of the sensor. By use of the circuit, the output of an infrared sensing amplifier imitates the output of a conventional flame rod sensor, and provides an output signal compatible with the output of a flame rod to the input to a flame signal processor.

Abstract: Apparatus for fixing a member at any angular position to the non-circular cross section of a shaft has an insert formed of a relatively soft material and a clamping element fixed to the member. The insert has a central bore whose cross section matches the shaft section cross section, a circular periphery, and a slot between the periphery and the central bore. The clamping element is formed of relatively hard, rigid material, and has a bore in surrounding relation to the periphery of the insert and conforming to it so as to permit rotation of the member with respect to the insert while the clamping element bore is undistorted. There is at least one tooth on the periphery of the clamping element bore projecting radially inward toward the insert. Preferably the periphery of the clamping element bore is completely knurled instead of having a single tooth.

Abstract: The joint between two nearly rigid, mating walls has a tongue on one wall's surface and a groove on the other wall's surface which have special cross section shapes cooperating to resist penetration of the joint by fluids such as water. At least one of the walls is formed of a plastic material which deforms under compressive loading. The shape of the tongue includes sides thereof which intersect the end to form corners defining the longitudinal edges of the tongue. The groove has walls which converge toward each other at the bottom of the groove from a mouth wider than the width of the end of the tongue. The shape of the groove forms a line of contact with each of the tongue's corners when the tongue is mated with the groove. During assembly, the corners of the tongue are forced into the walls of the groove by some type of clamping mechanism so as to at least slightly deform at least one of the tongue and groove.

Abstract: The apparatus controlling operation of a digital thermostat mounted in an enclosure corrects the internally measured temperature for heat generated within the thermostat enclosure by the switching element controlling operation of the load, typically a HVAC unit. The actual ambient temperature is derived by subtracting from the internal temperature a correction value which follows the fraction of total time the switching element conducts power for the HVAC unit (duty cycle). The duty cycle is preferably multiplied by a scale factor and the difference between the ambient temperature as currently calculated and the internal temperature to form the correction value.

Abstract: A driver circuit for an ultraviolet detector (UV) tube discriminates between firing of the UV tube in response to ultraviolet radiation impinging on it and a high resistance short between its output terminals. A capacitor charged on half cycles of AC power applied to the circuit discharges partially when the UV tube fires. This charge is transferred to a second capacitor to create a voltage displaced from ground. Each time the UV tube fires, the steep wave front generated thereby is passed by a high pass filter to a switch which momentarily grounds the voltage on the second capacitor through a resistor. The rapid change in the switch element's voltage signifies the presence of ultraviolet radiation on the UV tube.

Abstract: A microprocessor-based power switching circuit responds to a common form of noise by disconnecting power from the controlled apparatus. The microprocessor provides an alternating voltage when power is to be provided, and the alternating voltage is converted by a detector circuit to a voltage close to ground which cuts off a transistor. When the transistor is cut off, an interface circuit places a thyristor which performs the actual power switching, into conduction. Noise on the base of the transistor can only drive it into conduction which then puts the thyristor into non-conduction.

Abstract: A rotary actuator uses a two degree of freedom gear train with three torque members to provide torque to the output element from a first torque member. The torque is supplied to a second torque member from a drive motor. A torsion spring on the third torque member is normally wound tight and held wound by a brake which locks the third torque member during normal operation when electrical power is available for the drive motor. When power is lost, the brake releases the third torque member, allowing the spring to apply torque to the third torque member to drive the output element through the first torque member to a return position. This allows loads such as valves to be returned to a safety condition upon loss of electrical power to the system of which the load and the actuator are a part.

Abstract: A transfer sheet for use in printing of patterns such as alphanumeric characters onto a keyboard or other workpiece from the transfer sheet where the patterns are originally formed has a realignment area in which a plurality of slits are formed. The slits allow at least one portion of the transfer sheet to be repositioned with respect to at least one other portion to improve alignment of the patterns with respect to the workpiece. The patterns may become misaligned because of inherent dimensional instability of the transfer sheet arising from temperature or humidity variations.

Abstract: An actuator suitable for use with a valve has a design allowing for easy control or adjustment of the force applied to the valve. The actuator motor has a cam which operates a follower surface of a spring-loaded arm mounted for rotation on a carriage. The carriage is mounted for linear motion and connected to the control element of the valve. The actuation force can be controlled or adjusted by changing the relative positions of the arm's center of rotation, the point on the arm at which the spring applies force, and the position of the cam. In a preferred embodiment, the position of the arm's center of rotation is changed by moving a pin from one set of holes in the carriage and the arm to a second set of holes in the carriage and the arm.

Abstract: A timed contact switch apparatus has a conventional pushbutton placing a main switch in an actuated state when the pushbutton is depressed. A timing circuit is activated by the pushbutton to provide power to activate an electromechanical latch which holds the main switch in its actuated state while the timing circuit times out. Preferably the timing circuit operation is initiated by output of a Hall sensor which is controlled by a magnet whose position is mechanically linked to the position of the pushbutton.

Abstract: A programmable timer for turning a light on and off in response to changing sunset, daylight savings time, and other programmable conditions. The programmable timer includes an input device, a microprocessor, and a switch. The input device provides calendar, geographical, and daylight savings information to the microprocessor, which stores the programming information. The microprocessor computes an effective switching time from the stored information. The microprocessor employs program logic that compares the effective switching time to the current time to generate a timing control signal. The timing control signal, in turn, causes the switch to turn a light on and off. In the preferred embodiment, the microprocessor and the switch are included within a housing which mounts on a wall in place of a normal light switch. A liquid crystal display is disposed on a face of the housing to provide a read out of the programming information and of the time of day.