Patent DE-19950901-A1 (DE)
Title: Sliver monitor at a drawing unit has sensors at the sliver passage formed by a keyed and grooved roller pair at the entry to the drawing unit to show deviations in the sliver thickness and other irregularities
Inventor: LEIFELD FERDINAND
IPC: B65H63/06
Filed: 1999-10-22
Abstract: The appts. to measure the thickness and/or irregularities in slivers, at the drawing unit of a spinning assembly, has a fixed contact roller (9) and at least one sensor. They are located in front of the passage zone formed by a pair of rollers (7,8) with a slot and key structure, and work together with the grooved roller (8).  The keyed roller (7) is fixed, and has two or more keys. The grooved roller (8) has two or more grooves, with a sensor at each groove. Each sliver (5) moves through the space formed between a groove and its associated key, and the base of the groove is a counter surface for the sensor, while the side walls of the groove support the moving sliver (5). The sensor is moved by irregularities in the sliver (5), and generates control pulses. Each tensed sensor is moved by changes in each sliver (5) structure, and their shifts are added together. All the sensors are linked to a rotating holder, held under tension, to give the added shifting movements. The sensors are held under tension by a spring, and pref. a leaf spring, secured at one end, for the free end of the sensor to bear against the sliver. The counter surface can be the moving mantle surface of the grooved roller (8). A limit stop is for the deflection of the sensors, which are parallel to each other. The sensor holder is a longitudinal beam, axially parallel to the key and groove rollers (7,8), and has torsional stiffness as a torsion rod mounted in a rotating bearing at least at one end side. A monitor registers any rotation in the holder, as an inductive path movement monitor or expansion measurement strips. The separate sensors register changes in sliver thickness at a number of points across the width, to be gathered by the holder as a mean value, so that the actual mean value can be corrected if it deviates from a nominal value. The sensors are over the grooved roller (8), to extend into the gap between the grooved roller (8) and the key roller (7), with at least one fixed limit stop for the sensors. The sensor holder can be an extruded hollow profile, with a rod or bolt or pin forming an axis at the ends. The sensors are linked to an electronic control unit (26), to process the sensor readings at the slivers (5). The assembly is located at the entry into the drawing unit. The scanning point is at a gap from the clamping point between the key and groove rollers (7,8) which is less than the fiber length in the slivers. The open groove side walls, at the roller (8), are rounded or chamfered, and the sensors can work with the groove side walls and a fixed counter unit. A sliver guide, in front of the monitor station, has a number of longitudinal grooves as passages for the slivers (5), with rounded or chamfered entries and exits at the guide grooves. The keyed (7) and grooved (8) rollers are in fixed positions, in operation, with an adjustment to set the gap between them.