Abstract: A method for making vitreous bonded grinding wheels having a porosity of from 20 to 55% by volume is provided that reduces or prevent shrinkage. The method includes a step of mixing unclad, non-abrasive, non-metallic, particulate, inorganic solid shrinkage control agent with the abrasive grain, vitreous matrix precursor and other ingredients for producing the wheel. Non-abrasive hexagonal boron nitride is a preferred shrinkage control agent and may be used in amounts ranging for 1 to 10% by volume based on the volume of the grinding wheel. Reduced shrinkage of wheels made by the method over comparable wheels made without the shrinkage control agent is obtained.

Abstract: A radiant heating control system for a computerized tape laying machine is described in which the radiant heater is controlled so as to reliably heat thermoplastic composite tape to a processing temperature above the melting point of the thermoplastic matrix irrespective of velocity or change in velocity of the tape as it travels from a spool of tape to a tape application point for application to a layup tool or the like.

Abstract: Interface circuits for electromagnetic position transducers are provided to reduce the effects of capacitive coupling occurring in the conductive cabling between the position transducers and the associated interfaces located remotely therefrom. Capacitive coupling of excitation signals to the transducer output signals result in error signals appearing as cyclic error in measured positions. The magnitude of the coupled signals are substantially reduced by providing excitation signals symmetrical with respect to ground. The magnitude of the coupled signals are also reduced by presenting equal impedances relative to ground to the output signal return and signal paths. By reducing the effects of capacitively coupled signals, conducting cables for the excitation signals and the transducer output signals may be incorporated in a single shielded cable.

Abstract: A wireway channel assembly is provided for assuring unimpaired access to terminals of terminal strips placed in close lateral proximity to relatively deep wireways. A channel member having a substantially "U" shaped cross section includes at least one oblique flange portion in a side thereof. A first wireway is mounted to the inside of the "U" at the base thereof,and a second wireway is mounted to the outside of the side of the channel including the flange portion. A terminal strip is mounted to the flange portion. Wires to be terminated at the terminal strip are routed through openings in the sides of the wireways to the terminals as is conventional.

Abstract: A method of case hardening ferrometallic parts that avoids the use of protective coatings or shields is provided. The process comprises the steps of a) carburizing the entire part, b) machining the carburized part to form first and second surface regions wherein the second surface region has a carbon content at least 100% greater than the carbon content of the first surface region, c) heating the machined part at a hardening temperature with the entire part in contact with a gaseous atmosphere containing a source of carbon and a carbon content of from 85% to 115% of the carbon content of said first surface region, and d) quenching the part.

Abstract: There has been discovered the increased E-Modulus and grinding performance of vitreous bonded sol-gel abrasive grit abrasive articles, particularly abrasive grinding wheels, by the incorporation therein of inorganic, non-metallic bubbles. In a practice of the invention the abrasive article comprises a) an abrasive phase having sintered sol-gel alumina abrasive grits and second abrasive grits that are not of the sintered sol-gel type, b) a vitreous bond and c) essentially hollow, essentially spherical alumina particles having a softening temperature at least 50.degree. F. greater than the firing temperature of the vitreous bond.

Abstract: An apparatus for measurement of absolute position of a movable machine member is provided. The machine member is moved by a motor and reduction device producing rotation of the machine member in proportion to relative rotation of the motor rotor and motor stator. Two angular position measuring devices provide output signals representing relative positions related to the machine member position and differentiated one from another.

Abstract: A spatially-clocked system in a program controlled tape layer corrects for tape displacement error by rotating the tape application member after a predetermined length of tape is applied rather than on a temporal basis. An interpolator is provided to determine spatial clock period displacement in a temporally-clocked control system.

Abstract: A method for making vitreous bonded abrasive articles, particularly grinding wheels, is provided that includes the step of blending sugar/starch particles into the other ingredients for making the wheel. The sugar/starch particles are intimate combinations of sugar and starch. Wheels of improved performance are obtained compared to similar wheels made by a comparable method not including the step of blending sugar/starch particles into the abrasive grain, vitreous bond material and other components used for making the wheel.

Abstract: A transducer interface circuit is provided having means for detecting loss of connection of a transducer to the interface circuit. The interface circuit is intended for use with a transducer providing an output between two electrical poles of opposite polarity. Differential inputs of a differential amplifier are connected to the transducer poles. A bias current source is provided proximate the amplifier at least at one input, and the other input is connected to ground. Loss of connection between the transducer and amplifier results in saturation of the amplifier output.

Abstract: A machine and control are provided for effecting motion of a function element, such as an adhesive material dispensing gun, and controlling the operation of the function element by means of a control signal proportional to the velocity of a workpoint associated with the function element. The control produces a velocity signal representing the velocity of the workpoint, calculates the value of a control signal using the velocity signal and predetermined constant defining the constant of proportionality and zero velocity output and applies the control signal to a digital-to-analogue converter to produce an output signal for controlling the function element.

Abstract: A method and apparatus are provided for managing a plurality of analogue signals for digital control. Analogue input signals received from a process are periodically sampled and converted to digital input signals for access by a digital control. Digital output signals produced by the digital control are converted to analogue output signals and stored for continuous availability to a controlled process. The sampling and conversion of analogue input signals as well as the conversion and storage of analogue output signals is conducted asynchronously relative to the activity of the digital control by a predetermined program of control signals repetitively produced in response to a clock signal.

Abstract: A method is provided for effecting numerically controlled machining operations at a predetermined location. A reference feature is fixed proximate to the predetermined location and the location of a reference surface thereon is measured prior to machining to produce reference surface signals representing the coordinates of the reference surface. Location correction signals are produced in response to the reference surface signals, the location correction signals representing the difference between the measured location of the reference surface and the actual location thereof. The machining operation is performed in response to the location correction signals to effect the machining operation at the predetermined location.

Abstract: A method and apparatus are provided for producing a control signal by digital computation for controlling an element affecting a process. The process is described by a sequence of activities, and the onset of each activity is marked by a predetermined change of a process parameter. An event detector is provided for detecting the occurrence of predetermined changes of process parameters in response to data included within event detector data blocks. The event detector data blocks include data defining the desired response to the detection of a predetermined change of a process parameter. The control signal is produced in accordance with a selected predetermined algorithm using data included in algorithm data blocks. A first event detector data block and a first algorithm data block are selected defining a first predetermined change of a process parameter and a first algorithm.

Abstract: An apparatus is provided for controlling the execution of functions associated with the automatic operation of a manipulator. While traditional function execution has been associated with arrival of a workpoint at or proximate to a predetermined point, the present invention provides for plural function execution between predetermined points. Two alternative embodiments are provided: a first embodiment controls a single output interface type and is unrelated to functions associated with predetermined points; a second embodiment provides multiple executions of any function normally associated with a predetermined point. Spacing between function executions associated with either embodiment is controlled as a function of distance specified by the operator. To produce a desired spacing, feedrate reduction is automatically effected in the event a programmed feedrate is incompatible with a specified function execution interval.

Abstract: An apparatus and method are provided for creating and revising programs for numerically controlled machines. First, generalized data block signals are produced, the generalized data block signals representing alphanumeric words defining block types, workpiece material types, work surfaces, workpiece features and machining operations. Then, machine control instruction block signals are produced in response to the generalized data block signals, the machine control instruction block signals represent alphanumeric words defining machine member motion in the form and format required by a particular numerical control. The generalized data program may be created by a machine operator using data obtained from the workpiece design data. Generalized data program creation and revision is accomplished without regard for the data requirements and limitations of a particular machine and control combination by which the workpiece is to be processed.

Abstract: A method and apparatus are provided for providing for controlled oscillation of a tool centerpoint associated with a function element carried by manipulator simultaneously with motion of a workpiece feature relative to a predetermined location. The tool centerpoint describes a predetermined pattern relative to the workpiece feature as a result of the combined motion. Tool centerpoint oscillation occurs in an oscillation path between two extremes determined by pattern parameters defining pattern amplitude measured with respect to a pattern longitudinal axis. The direction of the oscillation path is defined by input signals representing angles measured relative to a rectangular coordinate system used for defining the predetermined location. The rate of tool centerpoint motion is defined by an input signal representing velocity.

Abstract: A machine for program controlled working a material with laser light is provided. The machine includes first movable members for effecting changes of position of a tool centerpoint associated with a function element carried by the machine. Second movable members effect changes in attitude of the function element through the tool centerpoint. A laser light beam is focused to a focus point by a focusing element supported by one of the second members. The laser light beam is conducted to the focusing element by an articulated light pathway from a laser light source. The articulated pathway comprises tubular segments connected at joints to redirect the laser light beam from one tubular segment to another. Each segment is mounted to the joint so as to be rotatable about the longitudinal axis of the segment. Adjustable stops are provided to limit the range of rotation of tubular segments as required.

Abstract: A method and apparatus are provided for controlling interpolated linear motion of a tool centerpoint associated with a function element carried by a machine. The motion is defined by input signals representing locations relative to an input coordinate system and path velocities therebetween. The machine includes at least one member rotating about an axis which is subject to movement at a velocity greater than the path velocity. Control is effected by producing projected velocity signals for the machine axes for each interpolative iteration and reducing the iterative path velocity in response to detecting a projected axis velocity in excess of an associated axis velocity limit. The control is applicable to machines incorporating a structure in which members must instantaneously change position to maintain the tool centerpoint on the path.

Abstract: A method and apparatus are provided for cooperatively controlling motion between a tool centerpoint associated with a function element carried by a manipulator and rotation of a workpiece carried by a positioner. The tool centerpoint follows a linear path interpolated between programmed locations at a velocity resulting in a relative velocity between the tool centerpoint and the workpiece surface equal to a programmed velocity. Differences in radial distance of the tool centerpoint from the axis of rotation of the workpiece at successive programmed locations result in incremental velocity modifications along the path to maintain the relative velocity at the programmed value.