Abstract: A pressure adjustment screw for a fluid flow control device cannot for safety's sake be rotated within a threaded cylindrical bore on the device's body to withdraw it beyond an extreme pressure level safety setting. To allow field adjustment of the set point pressure and at the same time to prevent withdrawal of the adjustment screw beyond the extreme pressure level safety setting, a stop collar is fixed within the cylindrical bore in a position contacting the adjustment screw when the adjustment screw is in its extreme pressure level safety setting. The invention includes a number of means for fixing the stop collar in this position, as do methods for fixing the stop collar in this position.

Abstract: A burner system has a control system which operates to prevent startup of the burner if an airflow switch indicates presence of combustion air flow before startup of a blower which provides the air flow. If the airflow switch later indicates absence of air flow before startup, then startup can proceed normally without operator intervention. Power for startup is supplied through the normally closed contacts of a safety relay. The winding of the safety relay receives power through the airflow switch. When the airflow switch is closed the safety relay winding is energized, opening the normally closed safety relay contacts and thereby blocking burner system startup, but only unit the airflow switch opens.

Abstract: Empty component locations are detected on an assembled circuit board where the component locations are marked with spots of a fluorescent substance before assembly. The circuit board is exposed to stimulating radiation by a radiation source causing luminescence from the spots of fluorescent substance on which the stimulating radiation is impinged. The circuit board is then examined for the luminescence to determine whether the components are between the spots and the radiation source.

Abstract: A communication network has one master node which maintains an active master list (AML) containing the node addresses of all nodes to which the token will be passed. When nodes are added or deleted from the network, it is efficient in terms of data bus occupancy and individual processing time by the nodes if the successor address for each node is broadcast in a single message, and the availability of an AML makes this possible. The network has the capability of efficiently updating the AML whenever the configuration of the network is so changed.

Abstract: A burner control system has a microprocessor for testing parameters of operation and for indicating deviations from a preset range for each. The sensors monitoring the parameters provide their outputs as analog voltages to analog to digital (A/D) converters which provide the parameters in digital form. Tests using preset voltage standards increase the likelihood of A/D converter accuracy. In addition, as operating conditions for the burner change, different preset ranges are used for each sensor output when testing them so as to provide maximum confidence of proper burner operation.

Abstract: A communication system has a first node which transmits on a data bus messages each having a preamble having a predetermined format including a message type and the message length, and a plurality of second nodes receiving messages from the data bus and including elements which can determine that the preamble in each message has the predetermined format. The preamble is particularly useful for allowing the second nodes to quickly detect messages not directed to those nodes of which the elements form a part, allowing the node to ignore the remainder of the message. This allows the individual nodes to exclude the message interpretation for detecting message directed to them, from their processing tasks thereby improving the effective processing speed of the network.

Abstract: A permanent magnet, alternating current motor having a variable hysteresis output coupling has an annular permanent magnet rotor caused to rotate within a stator structure. This permanent magnet rotor is capable of being shifted laterally to engage or disengage a hysteresis drag cup output device. With this arrangement either an off-on output torque can be provided, or the output torque can be modulated.

Abstract: A flame safeguard control system using a microcomputer is disclosed. The microcomputer responds to the flame signal as provided from a normal flame amplification chain and an analog-to-digital converter. A safety backup circuit in the form of a redundant flame signal detection circuit analyzes the analog signal being provided to the analog-to-digital converter. In the event that the microcomputer is unable to shut the main fuel valve off, the redundant flame detection circuit becomes operative to deenergize part of a series circuit including the relay for the main fuel valve.

Abstract: A thin film magnetic recording head has a flux path in which during writing magnetic saturation occurs in the throat section of the leading pole rather than in the trailing pole. This keeps the stray magnetic fields generated in the area where the saturation occurs during writing from distorting the just-recorded data pattern in the medium, since the leading pole is spaced sufficiently far from the data pattern as it is created adjacent the trailing pole. Preferably, this is accomplished by making a cross section area of the flux path in the leading pole throat section physically smaller than the minimum cross section area in the remainder of the leading pole or in the trailing pole and is throat section.

Abstract: Apparatus for assembling a pair of high strength magnets and the common pole piece into a unit for use in a disk drive includes a bed with a channel in which the magnets can slide or translate, and a stop centrally located in the channel to prevent execessive impact between the magnets as they slide under the force of mutual attraction toward each other. A recess in the bottom of the channel below the stop is adapted to receive the pole piece, and the attractive force between the pole piece and the magnets firmly attaches the magnets to the pole piece in the desired location after they have been properly positioned with respect to the pole piece by interaction of the stop and channel walls with the magnets.

Abstract: An article which can be used cooperatively with a padlock for locking an accessory with a hole within its body such as the typical bicycle helmet, has a flexible cable loop with a stop permanently attached to it. The loop can be bent to allow it to enter the accessory hole and the stop is too large to pass through the hole without permanently distorting either the stop or the hole. The padlock is then used to attach the portion of loop passed through the hole to a convenient permanent fixture.

Abstract: A pivot assembly has a substantial amount of inherent frictional torque. A shaft has a clearance space between itself and a wall of its journal hole. A pliable tubular bushing is axially compressed within the shaft clearance space to create rotational friction between the shaft and the bearing journal. Such an assembly has diverse applications in areas such as the swivel for sailboat tiller extensions, toilet seat lid hinges, and hinged covers for electronic cabinets or other equipment.

Abstract: A method for use with an article of manufacture allows great accuracy in machining the edge of a face on a prism to a predetermined position respective a feature carried on the face and formed by deposition of insulating material. The preferred application for this invention is in accurately machining the transducing surface of a disk memory transducer assembly so that the throat height of the thin-film head carried on an end face of the assembly has a precise value.