Rieter

Movement of the flats

Index

The bars of the flats mesh individually, like an internally toothed wheel, with the recesses in a sprocket gear, and are carried along by rotation of the sprocket. The ends of the bars of the operative flats slide over a continuous bend – with metal-to-metal friction.

As the flats move at a very low speed compared with that of the  cylinder in principle, the flats can be moved forward or backward, i.e. in the same direction as or in opposition to the cylinder. If the flats move with the cylinder (forward), the cylinder assists in driving the flats and the removal of strippings is easier. Forward movement therefore gives design advantages. On the other hand, reverse movement (against the cylinder) brings technological advantages. In this system, the flats come into operative relationship with the cylinder clothing on the doffer side. At this stage, the flats are in a clean condition.

They then move toward the licker-in and fill up during this movement. Part of their receiving capacity is thus lost, but sufficient remains for elimination of dirt, since this step takes place where the material first enters the flats.

At that position, above the licker-in, the cylinder carries the material to be cleaned into the flats. The latter take up the dirt but do not transport it through the whole machine as in the forward movement system; instead, the dirt is immediately removed from the machine (directly at the point where the flats leave the machine).

A diagram by Rieter (Fig. 112) shows that this is not simply an abstract principle, demonstrating clearly that the greater part of the dirt is flung into the first flats directly above the licker-in. Rieter and Trützschler offer cards with backward movement of the flats.

Fig. 112 – Dirt take-up of the flats from the entry point A, dirt; B, flat number 1...40