COMBER
- The Feed
The web is fed over this shaft, which is rotated intermittently in time with the nipper cycle. Each shaft rotation represents less than a full revolution, gives a forward direction initially and then backward rotation
This back-and-forth rotation ensures uniform tension in the web and hence prevents false drafts, which could otherwise arise as a result of fluttering of the web as the distance between the stationary rollers and the feed rollers increases and decreases with the backward and forward movement of the nippers.
The eccentricity of the shaft compensates for these changes in distance.
The Feed Device
- There is no machine drive of the feed rollers as such; they are driven indirectly by the opening and closing of the nipper plates.
- Settings: Forward shift of the web by the feed roller into the opened nippers can be performed:
- while the nippers move forward (described above as forward feed); or
- When the nippers swing back (described as backward feed).
- Some types of comber can be operated in only one feed mode (forward feed), others can be operated selectively in either mode.
- Selection of the required mode then involves an adjustment. On the comber this can be carried out quickly and easily by replacement of the two drive change gears on opposite sides of the feed roller (Fig. 3).
- Rotation of the feed rollers to feed the lap sheet forward by 4.3 to 6.7 mm is derived from the relative movements of the upper and lower nippers.
- For example, in the case of forward feed, when the upper nipper plate is opened it rotates the roller via the ratchet (by one ratchet tooth) by withdrawing the pawl secured to the upper nipper plate. Whereas in backward feed, i.e. rotation of the cylinder as the nippers close, a pair of gear wheels and an internally toothed ratchet are needed.
- The change wheels can be replaced to adjust the type of feed and the feed amount per cycle
Nipper Assembly
The construction of the nipper assembly
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