US 3,938,119 A · Electro-mechanical thread supervisory apparatus

Abstract

A sensing lever, preferably a double-arm lever, is journalled over a fulcrum; one arm is engaged by the thread to be supervised, and further connected to operate an electrical switch; the other arm is subject to electromagnetic force derived from an interrupted, pulsed electromagnet. Pulsed operation of the electromagnet can be obtained by a signal derived from the switch of the lever itself, or from an extraneous source; upon attraction by the magnet, the contacts are opened; during a pulse gap, the thread tension depresses the lever, thus closing the contacts; the lever will, therefore, continuously vibrate and presence of an a-c signal across the switches will be indicative of: (a) presence of thread; (b) thread tension below a predetermined limit (excessive tension would overcome the pulsed reset force of the electromagnet); and (c) proper operation (jamming of the lever would likewise result in a d-c output from the switch).

Claims10

Dependent claims

Electro-mechanical thread supervisory apparatus having a deflectable mechanical arm (4) in contact with the thread (9) being supervised and deflected by pressure by the thread on the arm, comprising

electromagnetic means (1, 2, 3) acting on the arm in a direction counter the direction of pressure force exerted on the arm (4) by the thread (9), said arm being magnetically responsive to said electromagnetic means, said electromagnetic means being pulse-energized to cause the arm to vibrate;
arm movement sensing means (7, 8) connected to a source of electrical power (23, 23') and controlled by deflection of the arm due to pressure of the thread on the arm and generating pulses upon vibration of the arm (4);
and electrical detection means (15, 16, 17, 18;
37, 38, 39, 18') connected to and responsive to the generated electrical pulses and providing an alarm signal upon failure to sense vibration of the arm and thus generate pulses indicative of:
(a) absence of thread;
or (b) excessive thread tension;
or (c) jamming of movement of the arm.

4 more elements

Dependencies are inferred from the claim text.

Electro-mechanical thread supervisory apparatus

Life of this patent

Electro-mechanical thread supervisory apparatus

Life of this patent

Abstract

Claims10