Abstract: A frame is provided for mounting a fabric layer stack and retaining it in a substantially taut condition. The frame is supported for manually guided movement beneath a fixedly located stitch head and a detector is provided to produce signals representing the magnitude of frame translation, and thus the magnitude of stack translation. The detector signals are applied to control circuitry to actuate the stitch head at a rate related to stack translation speed. The frame is supported by bearings; wheels, slides, etc, which permit the frame to be freely manually guided across a frame supporting surface beneath the stitch head.

Abstract: A system which allows multiple senders to asynchronously transmit identification codes via a common communication channel (e.g., RF) to enable a central monitor to identify the presence (or absence) of each sender within the monitor's detection zone. Each sender is configured to repeatedly transmit a uniquely encoded identification frame. A frame, in accordance with the invention, is comprised of pulses spaced to minimize pulse collisions and configured to tolerate occasional collisions without impairing the monitor's ability to separately identify each transmitting sender. Each sender is configured to repeatedly transmit a unique identification frame characterized by a pulse pattern comprised of active intervals spaced by inactive (or “quiet”) intervals. The inactive intervals have variable length durations which are preferably pseudorandomly selected so that each sender defines a unique sequence of inactive interval durations.

Abstract: A quilting apparatus for enabling a user to freely move a stack of fabric layers across a planar bed relative to an actuatable stitch head. The apparatus includes a motion detector which detects the movement of the stack and controls the actuation of the stitch head. Consequently, the apparatus functions to synchronize the delivery of stitch strokes by the head with the manually controlled movement of the quilt material stack. This frees the user to move the stack over a wide range of speeds, to start or stop movement at will, and to guide the stack in any direction across the planar bed.

Abstract: A system which allows multiple senders to asynchronously transmit identification codes via a common communication channel (e.g., RF) to enable a central monitor to identify the presence (or absence) of each sender within the monitor's detection zone. Each sender is configured to repeatedly transmit a uniquely encoded identification frame. A frame, in accordance with the invention, is comprised of pulses spaced to minimize pulse collisions and configured to tolerate occasional collisions without impairing the monitor's ability to separately identify each transmitting sender. Each sender is configured to repeatedly transmit a unique identification frame characterized by a pulse pattern comprised of active intervals spaced by inactive (or “quiet”) intervals. The inactive intervals have variable length durations which are preferably pseudorandomly selected so that each sender defines a unique sequence of inactive interval durations.

Abstract: A system which allows multiple senders to asynchronously transmit identification codes via a common communication channel (e.g., RF) to enable a central monitor to identify the presence (or absence) of each sender within the monitor's detection zone. Each sender is configured to repeatedly transmit a uniquely encoded identification frame. A frame, in accordance with the invention, is comprised of pulses spaced to minimize pulse collisions and configured to tolerate occasional collisions without impairing the monitor's ability to separately identify each transmitting sender. Each sender is configured to repeatedly transmit a unique identification frame characterized by a pulse pattern comprised of active intervals spaced by inactive (or “quiet”) intervals. The inactive intervals have variable length durations which are preferably pseudorandomly selected so that each sender defines a unique sequence of inactive interval durations.

Abstract: Apparatus for use in a glider for indicating the rate of vertical air mass movement. The apparatus includes sensing means for detecting both glider airspeed and acceleration orthogonal to the plane of the wings. This information is used to modify the output display of a conventional variometer to eliminate the effects of drag.

Abstract: A strip material (18) for forming an inductive loop (10) adapted to be applied to the surface of a roadway (12). The strip material (18) consists of and the loop (10) is formed from a ductile, flexible, flattened, extensible conductor (20) and a protective covering (22). A protective underlayment (24) is optional. The conductor (20) may be formed from a compressed, flattened metallic wire braid (28) or from a wire mesh containing 25% to 75% voids. The protective covering (22) may be formed from either combination unvulcanized elastomer precursor base sheet (30) and a vinyl based polymer support film (32), or a covering (26) selected from the group of epoxy, polyester, urethane and polyurethane.

Abstract: A convertor is used having an impedance responsive to the magnetic field intensity of the earth. The convertor may be coupled to a detector for monitoring the impedance of the convertor and generating a call signal responsive to the change in impedance. Generally, the impedance is primarily inductance and the detector is an oscillator using the convertor in a resonant circuit with a frequency monitor coupled to the detector. The convertor is an open magnetic structure having a non-linear BH curve biased by the earth's magnetic field. The open magnetic structure is a core of a highly permeable material which approaches saturation under the influence of the earth's magnetic field, with the axis of the core at least partially aligned with the magnetic flux lines of the earth's magnetic field, and a coil wound around the axis of the core.

Abstract: Apparatus for use in combination with an inductive loop for detecting metal objects, e.g. vehicles, in the immediate vicinity of said loop. The loop may, for example, be a coil of wire buried in a roadway in a plane parallel to the roadway surface. Oscillator circuitry is operatively connected to the loop with the frequency of oscillation being determined by the loop inductance, which in turn is dependent on whether or not the vehicle is over the loop. The loop frequency is monitored by digital circuitry including a loop counter which counts loop oscillator cycles and a duration counter which measures the time duration of a fixed number of loop oscillator cycles. The measured time duration is compared with an adaptable reference duration to ascertain whether the loop oscillator frequency has increased or decreased. The presence of a vehicle over the loop decreases loop inductance, increases loop frequency, and thus reduces the measured time duration of a fixed number of loop cycles.

Abstract: Apparatus for use in combination with multiple inductive loops for detecting metal objects, e.g. vehicles, in the immediate vicinity of each of said loops. Each loop may, for example, be a coil of wire buried in a roadway in a plane parallel to the roadway surface. A common oscillator circuit is operatively connected to each loop on a time shared basis with the frequency of oscillation at any time being determined by the inductance of the connected loop. The inductance in turn is dependent on whether or not a vehicle is over the loop. Successive scan cycles are defined with multiple loop phases occurring during each scan cycle.