Rieter

Construction of the flats

Index

The bars of the flats are made of cast iron (nowadays aluminum profiles, Fig. 109) and are somewhat longer than the operating width of the card, since they rest on adjustable (so-called flexible) bends to the left and right of the main cylinder and must slide on these guide surfaces. Each bar is approximately 32 - 35 mm wide (might change to smaller widths). The bars are given a ribbed form (T-shape) in order to prevent longitudinal bending. A clothing strip (108 b) of the same width is stretched over each bar and secured by clamping, using clips (c) pushed onto the left- and right-hand sides of the assembly. Since some space is taken up by the upper edge of each clip, only a strip about 22 mm wide remains for the clothing (hooks or teeth). For this reason, the flats do not enable an absolutely continuous carding surface to be formed above the cylinder; there are gaps between the clothing strips.

The bars are thickened at their left- and right-hand ends in order to take fixing screws corresponding with screw holes in the chains; the individual bars can thus be secured to respective links of the circulating chains (Fig. 110).

The slide surfaces on the bars are not ground level but are slightly inclined (Fig. 111). Therefore, as the flats move over the cylinder, they have a slight tilt, i.e. viewed in the direction of material flow the leading edge of each bar is spaced further from the cylinder clothing than the trailing edge (1). The result is that the fibers are not pushed along in front of the flats, but can pass underneath them.

Fig. 108 – Mounting of the clothing strips (b) on the flat bars (a) using clips (c)

Fig. 109 – A modern flat construction

Fig. 110 – Securing the flat bars to the endless chain by means of screws

Fig. 111 – Inclined gap between flat clothing and main cylinder clothing