A gas flow control device including a body means defining an inlet, an outlet and a gas flow passage therebetween a main valve disposed in the passage and comprising a primary valve movable between a closed position that prevents flow through the passage and an open position that permits flow therethrough; a primary diaphragm operably connected to the primary valve and supported by the body means, the primary diaphragm defining within the body and separating a primary reference chamber from a primary regulator chamber located in the passage and the pressure in the primary reference chamber exerting a force tending to open the primary valve; and a primary bias means biasing the primary valve toward its open position. Also included in the device is a secondary valve disposed in the passage between the primary valve and the outlet, the secondary valve movable between a closed position that prevents flow through the passage and an open position that permits flow therethrough; a secondary diaphragm operably connected to the secondary valve and supported by the body, the secondary diaphragm defining with the body and separating a secondary reference chamber from a secondary regulator chamber located in the passage and the pressure in the secondary regulator chamber exerting a force tending to close the secondary valve; a secondary bias means biasing the secondary valve toward the open position and a control passage providing communication between the primary reference chamber and the outlet.

In an automatic ring textile machine, e.g., a spinning frame, for processing a strand which is equipped with a traveling tender carriage capable of detecting the existence of an abnormal condition at a station on the machine and servicing the station to restore it to normal operation, of the type shown in U.S. Pat. No. 3,403,866, an improved mechanism for threading the strand in the ring is disclosed.

In order to coordinate the movements of two movable parts on a spinning frame and a service robot, a system is provided in which one part carries two sensors which are used to detect the position of the other part within the respective measuring ranges of the sensors. This system provides for rough positioning of one part to the other at a relatively high speed until the first sensor detects the second part. Thereafter, coordination of the movements of the two parts takes place within narrow tolerance limits using the second sensor which has a narrow measuring range.

Controlling the stop of the feed of roving in a spinning machine in which yarn is wound on spindles through travelers rotating on rings and in which a stop motion is actuated to stop the feed of the roving to drafting rolls in response to detecting a yarn break and is subsequently deactuated to permit roving feed during a yarn break repair operation. The stop motion includes an arcuate stop member rotatably mounted on one of the drafting rolls for rotation into disposition between opposing rolls to separate the rolls and stop roving feed, with the stop member having a projecting cam engaging in a recess in a slide member that is manipulated by a spring and electromagnetic device to control manipulation of the stop member. Response of the stop motion to the detection of a yarn break is deactivated upon initiation of a yarn break repair operation and is maintained until the detection indicates that spinning has resumed for a predetermined length of time sufficient to indicate that the yarn break has been repaired, with the deactivating continuing in the event a yarn break has not been successfully repaired. The repair operation is repeated until successful or for a selected number of unsuccessful attempts, at which time a false simulation of resumption of spinning is given to reactivate response of the stop motion to the yarn break detection for deactuating the stop motion and to stop roving feed. Device for sensing whether a yarn break has been successfully repaired and the device for providing a false simulation are incorporated in an electronic circuit on the yarn break repair device, which circuit is connected through an optical transmission device to an electronic circuit on the spinning machine that includes the stop motion deactivating device.

A method and apparatus for initiating feed of yarn on a machine for taking yarn from a supply, processing it and rewinding it. A short length of processed yarn is led back through a series of guide wires to a vacuum receiver for holding the free end of the yarn. The wire guides are actuated to form a large loop so that the processed yarn will be fed over the input roller and the output roller, so as to pick up yarn from the supply. The lower roller of the feed roller assembly is elongated to aid in the looping and lateral in-feeding of the processed yarn loop. The previously processed yarn, after it is fed around the input and output rollers and has picked up the additional yarn to be processed is pulled from the vacuum retaining system and incorporated in the processed yarn.