The Warner & Swasey Company

The United States of America As Represented by the Administrator of the

Richard L Patterson

Jyoti P Mukherjee

Ronald C Cull

Robert A Furmanek

Andrew J Fedak

David J Gee

Edward L Slaby

Allen H Rose

Denver R Dye

Stephen M Zielaskiewicz

The present invention discloses a method of detecting and locating current imbalances such as ground faults in multiwire systems using the Faraday effect. As an example, for 2-wire or 3-wire (1 ground wire) electrical systems, light is transmitted along an optical path which is exposed to magnetic fields produced by currents flowing in the hot and neutral wires. The rotations produced by these two magnetic fields cancel each other, therefore light on the optical path does not read the effect of either. However, when a ground fault occurs, the optical path is exposed to a net Faraday effect rotation due to the current imbalance thereby exposing the ground fault.

Method of locating ground faults

A tool force sensor assembly (20) generates an electrical signal which is related to the change in force applied by a tool (24) to a workpiece (28) and is indicative of the wear condition or failure of the tool (24). The sensor assembly (20) is mounted in force transmitting relationship between a movable tool support (30, 36) and a nut member (44, 45) which is driven by screw shaft (40, 41). The sensor assembly (20) comprises a plurality of ring-shaped piezoelectric transducers (48) which are held in preselected, circumferentially spaced relationship to each other around the screw shaft (40, 41) by a retainer ring (56, 58) which is sandwiched between a pair of load distribution plates (52, 54). Fasteners (46) extend through each of the transducers (48) and mount the sensor assembly (20) between the nut member (44, 45) and the tool support (30, 36). An alternate form of the retainer ring (80) is formed by molding the transducers (48 ) within a layer of flexible molding material which allows the transducers (48) to seat properly against the load distribution plates (52, 54). A pair of the sensor assemblies (20) may be respectively mounted on the slide (30) and carriage (36) of a machine tool (22) in order to monitor tool force in two mutually orthogonal directions.

Tool force sensor and method of making same

A device-implemented method for monitoring the cutting condition of a machine tool during machining of a workpiece senses acoustic emissions resulting from the machining of the workpiece, produces an electrical signals which varies in accordance with changes in the sensed acoustic emissions, and variably amplifies the signal by a gain level selected by a set of digital data stored in the memory (12) of a computer (15). The signal is amplified by an amplifier (32) having a variable gain input (34) controlled by the computer (15). The signal is processed by two circuits (36, 40, 56 and 36, 42, 50) which respectively generate two separate sets of digital data representing the cutting condition of the tool. The computer (15) compares the data with memory-stored information to determine whether an alarm signal should be generated. A circuit (75) is provided for generating a control signal indicating that cutting of the workpiece has commenced.

Method and apparatus for monitoring the cutting condition of a machine

An apparatus and method for tool condition and failure monitoring system for predicting imminent tool failure by sensing acoustic emissions from a cutting operation converting the emissions into an electrical signal filtering the electrical signal and using a 'count rate' technique on the filtered signal to generate a signal indicative of imminent failure. To improve the prediction, the filtering includes removal of low frequency and d.c. signals and the imminent failure is indicated only after several successive periods of a triggering level of count rate.

Tool condition and failure monitoring apparatus and method

Growing community of inventors

South Euclid, OH, United States of America

Richard L Patterson