GB2188072A - Improved web take-off for carding apparatus - Google Patents

Abstract

A web take-off includes a doffer cylinder 1 and a fluted stripper roll 2 which co-operates with a stripper blade 4 to separate a carded web from the surface of the doffer cylinder 1, for onward transmission to a condensing trumpet 6 at a calender roll pairs. A pair of condensing rollers 8 can be moved from their out-of-the-way positions 8' to an operative condensing position 8 to condense the carded web into a sliver, without the need for the presence of moving conveyor belt surfaces to convey the carded web transversely to the condensing point. In the out-of-the-way positions the rollers 8 may lie in the plane of the web but outside the confines thereof. Again the rollers 8 may lie outside the plane of the web in another out-of-the-way position. <IMAGE>

Description

SPECIFICATION Improved web take-off for carding apparatus The present invention relates to carding apparatus, and in particular to an improved web take-off arrangement for carding apparatus.

British Patent No. 1,208,264 discloses carding apparatus in which the web from the doffer cylinder is passed over support rollers to a conveyor belt which moves continuously in a direction parallel to the axes of rotation of the carding and doffing cylinders and the support rollers so as to guide the collected web transversely to one side of the carding apparatus for condensing into a sliver.

British Patent No. 1,298,855 discloses an alternative configuration in which there are two conveyor belts which feed the carded web transversely inwardly towards the centre line of the carding apparatus for condensing.

It is an object of the present invention to provide an improvement in the latter form of web take-off.

Whereas in the two above-mentioned prior art disclosures, and in many cards built in accordance with those inventions, it has been considered important to provide a conveyor belt to guide the web transversely in such a web take-off, inwardly towards the condensing location on the doffing cylinder, and also to provide calender rolls to feed the web positively against the conveyor belt surfaces, we have now discovered surprisingly that the provision of a conveying surface is not necessary.

Accordingly, the present invention now provides a web take-off for carding apparatus, comprising a doffer cylinder, means removing the carded web from the doffer cylinder, and a pair of closely spaced rollers having substantially parallel axes to define condensing means for the web, which passes through the space between the rollers, whereby the web leaving the web removing means immediately contracts in width to pass between the two rollers without the need for moving conveyor belt surfaces to guide and to carry the web towards the condensing rollers.

In a preferred form of the present invention the rollers are mounted for movement between said closely spaced operative positions in which they define condensing means for the web, and out-ofthe-way positions which facilitate manual introduction of the web to a collecting trumpet before the rollers are brought into their operative position to define the condensing means for the web.

In arriving at their operative position, the condensing rollers may be moved laterally inwardly of the carding apparatus from widely spaced positions, or alternatively they may be moved into the path of the carded web from a position above or below the plane of that path.

In order that the present invention may more readily be understood the following description is given, merely by way of example, with reference to the accompanying drawings in which: FIGURE lisa side elevational view of a first form of web take-off in accordance with the present invention; FIGURE 2 is a top plan view of the web take-off of Figure 1; FIGURE 3 is a view corresponding to Figure 1, but showing an alternative embodiment of the invention; and FIGURE 4 is a top plan view of the web take-off of Figure 3.

In the drawings, a doffer cylinder 1 is clad with wire fillet or toothed carding wire in a manner known perse and rotates in the clockwise direction to carry the carded web upwardly towards the transfer point with a substantially longitudinally fluted stripper roll 2 which also rotates in the clockwise direction and therefore at the nip it has its circumference moving in a direction opposed to that of the doffer cylinder 1.

A support bar 3 below the stripper roll 2 carries a stripper blade 4 which has a strip of its surface close to the right hand edge as viewed in Figure 1 biased into contact with the exposed surface of the carded staple fibre web on the stripper roll 2 leaving the transfer point between the fluted stripper roll 2 and the toothed doffer cylinder 1.

As a result of the co-operation of the stripper blade 4 with the stripper roll 2, the web detaches from the stripper roll 2 and passes over the bar 3 in a horizontal direction towards a pair of calender rolls 5. Just preceding the calender rolls 5 is a condensing trumpet 6 which guides the condensed web, now in the form of a sliver 7, into the nip between the two calender rolls 5.

The action by virtue of which the web leaves the doffer roll 1 forthe stripper roll 2 at the transfer point is that the teeth on the doffer cylinder 1 have their points trailing and hence the fibres are readily able to be detached by the action of air currents generated by the existence of the slightly helically arranged longitudinal flutes of the stripper roll 2 contacting the stripper blade 4 and thus sucking the fibres off the rearward facing teeth of the doffer cylinder 1 to cause them to pass around the tip of the stripper blade 4 and then to pass between the stripper blade and the fluted stripper roll 2.

The reason for the slight helical configuration of the fluting on the stripper roll 2 is that this prevents chattering of the spring-biased stripper blade 4 during rotation of the stripper roll 2.

To condense the web into a sliver 7 and to guide it from the stripper blade 4 to the trumper 6, two closely spaced rollers 8 are provided, on parallel axes which extend substantially transversely to the general plane of the carded web leaving the stripper blade 4.

The plan view of Figure 2 shows, in broken lines, an out-of-the-way position 8' for each of the two condensing rollers and, in solid lines, a further operative position 8.

In order to piece up the carding apparatus associated with the web take-off of Figures 1 and 2, the operator first positions the condensing rolls 8 in the out-of-the-way position 8' and then slowly rotates the doffer cylinder 1 and the stripper roll 2 to bring the leading edge of the carded web leftwardly towards the trumpet 6.

Once the leading edge of the sliver is far enough from the stripper blade 4 to allow the carded web to be condensed manually into the trumpet 6, the operator gathers the web together and twists it into a sliver at the leading end so as to permit that leading end to be passed through the trumpet and thence to be entrained through the calendering nip between the calender rolls 5 and onward to the coiler (not shown).

This configuration is shown in Figure 2 in chain dotted lines.

Then the operator moves the two condensing rollers from the out-of-the-way position 8' to the operative position 8 which causes the web to become condensed at the rollers 8 and to adopt the configuration illustrated by the cross-hatching in Figure 2. As can clearly be seen, the carded web emerging from the stripper blade 4 is immediately condensed by the presence of the two rollers 8, and surprisingly the absence of any conveyor belt surface to guide the web inwardly towards the condensing rollers 8 leading the web towards the rollers 8 does not give rise to early rupture of the fragile carded web. The sliver emerging from the gap between the two condensing rollers 8 in their solid line operative position of Figure 2 then passes onwardly to the trumpet 6.

The waisted form of the two condensing rollers 8 helps them to condense the web and to hold it axially centered on the two condensing rollers.

If desired, the web may be guided on its leftward path from the stripper blade 4 by means of a guide plate such as that shown in our co-pending British Patent Application 8616812 (Publication No.

An alternative embodiment is shown in Figures 3 and 4 where the same reference numerals are used for analogous components and where the principal differences concern the motion of the condensing rollers 8 from their out-of-the-way position 8' to the condensing position 8. In this case the out-of-theway position 8' is below the position of the carded web during piecing, and the rollers are then moved up into the plane of the web as the web is guided to pass between them to be condensed at the same point as in the Figure 1 and 2 embodiment.

The shape of the condensing rollers 8 in Figure 3 is different from that of the corresponding rollers in Figure 1 in that, although the rollers in the Figure 3 embodiment are again waisted, they also have a hemispherically domed upper end to help them to guide the edges of the web over the heads of the rollers 8 and into the gap between the condensing rollers as the rollers rise into their operative positions.

Alternatively, if desired, the out-of-the-way position for the condensing rollers 4 could be above the plane of the carded web and the rollers then brought downwardly into position, but this has the disadvantage of cluttering the upper part in the vicinity of the path of the carded web and leads to a more complicated piecing process.

As with the embodiments of Figures 1 and 2, it would be possible to modify the embodiment of Figures 3 and 4 to incorporate the support plate of our said British Patent Application 8616812 (Publication No.

In both of the above embodiments the condensing rollers are preferably free to idle and are thus driven by virtue of contact with the web.

Claims (11)

1. A web take-off for carding apparatus, comprising a doffer cylinder, means removing the carded web from the doffer cylinder, and a pair of closely spaced rollers having substantially parallel axes to define condensing means for the web, which passes through the space between the rollers, whereby the web leaving the web removing means immediately contracts in width to pass between the two rollers without the need for moving conveyor belt surfaces to guide and to carry the web towards the condensing rollers.

2. A web take-off according to claim 1, and including a pair of calendering rolls defining a calendering nip downstream of the means for removing the carded web from the doffer cylinder, said condensing rollers being located between the web removing means and the caiendering rollers and positioned closer to the web removing means than to the calendering rollers.

3. A web take-off according to claim 1 or 2, wherein said condensing rollers are mounted for movement between said closely spaced, operative, position in which they condense the carded web by causing it to pass inwardly through the space between the two condensing rollers, and an out-ofthe-way position in which they are clear of the path of the carded web leaving the web removing means.

4. A web take-off according to any one of claims 1 to 3, wherein said means for removing the carded web from the doffer cylinder comprises a longitudinally fluted stripper roll and a stripper blade, the direction of rotation of the stripper roll and the doffer cylinder being the same so that their circumferential movements at their point of closest approach are opposed, whereby the presence of the flutes on the stripper roll co-operating with the stripper blade creates air currents which strip the fibres from the doffer cylinder to define a carded web on the stripper plate.

5. A web take-off according to any one of the preceding claims, wherein said condensing rollers have their out-of-the-way positions arranged such that they lie in the plane of the carded web leaving the web removal means, but laterally outside the confines of the web, whereby moving the condensing rollers inwardly to their operative position automatically gathers the carded web to form a condensed sliver by virtue of the presence of the condensing rollers.

6. A web take-off according to any one of claims 1 to 5, wherein said condensing rollers have their outof-the-way positions out of the plane of movement of the carded web leaving the web removal means, and are mounted for movement into the plane of the carded web for piecing of the associated carding apparatus, to bring the condensing rollers into their operative positions.

7. A web take-off according to claim 6, wherein said condensing rollers have dome-shaped upper ends to facilitate piecing.

8. A web take-off according to claim 4, or to any one of claims 5 to 7 when appendant thereto, wherein said web removal means include a support plate defining a stationary support surface to guide the carded web onwardlytowards said condensing rollers in their operative position.

9. A web take-off according to any one of the preceding claims, wherein there is a single pair of said condensing rollers having their operative positions at the mid-point of the axial extent of said doffing cylinder.

10. A web take-off according to any one of the preceding claims wherein said rollers are freely rotatably mounted on their own axes of symmetry and are driven by contact with the carded web.

11. A web take-off for a carding apparatus, substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 and 2, or Figures 3 and 4 of the accompanying drawings.