Background Art There has been an historical trend to increase the speed of textile combing machines (often referred to simply as "combs") to increase production rate, and most combs now operate at speeds above 200 c/min. However, further increases in speed are likely to be small, largely as a result of the use of relatively large strokes of the apron carriage. Smooth operation of a comb at very high speed will require very short strokes of the apron carriage.

Efforts to achieve higher comb speeds by using a shorter apron carriage stroke have concluded that there is a lower limit to the stroke, set by the need to control the tuft tails during the cycle to prevent them from being caught by the circular comb.

The apron carriages on recent commercial combs have oscillated through a distance of 80 to 90mm. On a current model comb this was reduced to 60mm, leading to a significant increase in the speed of operation. A benefit of reducing the apron carriage stroke is the reduction in the power required. Vibration is also reduced, which allows the speed of the comb to be increased. The technology used on all combs so far, including the latest models, limits the stroke of the apron carriage to no less than about 35mm.

In conventional combing systems, after each tuft is drawn off, it is supported by the top run of the apron, which is reversed to rewind the tuft so that the next tuft can be laid

into it. During the rewind, the tuft tail must be controlled so that it does not strike the circular comb. If this occurs, fibres in the tail that are caught by the circular comb may be carried away as unnecessary waste, leading to significant financial loss.

In current model commercial combs, tail control is achieved through the use of a "pneumatic tuft beater". This is simply a stationary suction funnel positioned generally beneath the drawing-off rollers at a distance that ensures capture of the rewinding tufts.

The suction system draws in the fibre tails and the funnel is positioned to be most effective when rewinding commences. An important feature of this system is that suction is reduced near the end of rewind to prevent loss of fibres as noil. In the comb disclosed in British patent 1057971, this reduction in suction is achieved by the use of a cover flap or the like.

British patent 1207441 describes an alternative means of reducing the suction by opening a flap or gate downstream in the suction system. Opening this flap or gate downstream reduces the air flow at the mouth of the funnel. In British patent 105791, it is also suggested that the position of the wide-mouth suction funnel can be varied during the working cycle, and that this movement of the funnel can be controlled positively, either from movement of the apron carriage or otherwise. However, when the apron carriage stroke is very short, it is not possible to move the funnel in closer to the nip where the suction is needed. This is because a stationary funnel that will control the tails will interfere with the motion of the beard as it is lifted from the circular comb.

French patent publication 2264899 describes a combing system in which the apron carriage is replaced with a fixed system, and the input side reciprocates. However, the input structure is substantially heavier than the output side incorporating the apron, and significant difficulties are likely to be met in oscillating the heavier input structure in comparison to the traditional practice of oscillating an apron carriage at the output side.

The present applicant believes that, in view of these likely problems, it is preferable to maintain the traditional approach. In French patent publication 2264899, the main suction duct for tail control is fixed to a frame component and has a protective guard component which is pivotally mounted on the duct to press against the apron, adjacent the bottom

drawing-off roller, to substantially close off the duct during the drawing-off stage and so to prevent loss of fibres.

For combs with an apron carriage, as the carriage stroke is reduced, it becomes extremely difficult to position a funnel so that it fulfils the role described above. In particular, the main problem using a stroke of, say, only 15mm is that at no stage is the mouth of the pneumatic tuft beater uncovered given the restrictions on where it can be placed. Even if the conventional pneumatic tuft beater is modified to allow for the short stroke by inserting it further into the combing zone, this will interfere with the presentation of the fringe or leading edge of the beard both to the circular comb and to the drawing-off rollers. A further problem is that the suction in such a funnel should preferably be completely eliminated during the start of tuft drawing-off, as the suction may cause the leading edge of the beard to be drawn into the funnel. The flap or gate system mentioned above is unable to totally eliminate suction, since it merely increases the total air cross- section of the duct that is being subjected to suction.

It is thus an object of the invention to provide a modification of the conventional textile comb that will permit operation at an apron carriage stroke substantially less than hitherto employed.

Summarv of the Invention The invention accordingly provides, in one aspect, textile combing apparatus, that includes combing means defining a combing zone, and means to feed an input beard towards the combing zone. Draw-off means is reciprocally moveable to draw off successive tufts from the input beard and to support each tuft in or adjacent the combing zone. Tuft control means is provided to control at least a portion of each successive tuft subsequent to being drawn off from the input beard, and includes structure extending about the draw-off means to in turn define a passage open to receive the tuft portion. This structure is disposed to control the tuft portion in the combing zone adjacent the draw-off means, and to shield the tuft portion from an adjacent segment of the combing means, and

is mounted for reciprocal displacement in synchronism with the draw-off means, whereby the aforesaid passage reciprocates, while open, with the draw- off means.

The tuft control means is preferably fixed relative to, and travels with, the draw-off means, and preferably includes a pair of drawing-off rollers defining a nip through which the tufts are drawn off, and a continuous belt providing an apron on which the tufts are supported and further transported. In existing commercial combs, the belt generally extends about the lower drawing-off roller. The tuft control means is preferably positioned to control a tail portion of the successive tufts at a location about one of the drawing-off rollers. In one embodiment, the tuft control means is provided adjacent one of the rollers, e.g. the upper roller, and the belt extends about the other roller. Said structure may include a plate means that also extends about the other roller whereby the passage open to receive the tuft portion is defined between the plate means and the belt.

In a particularly preferred embodiment, the apparatus includes duct means for applying suction to the passage, and means operable in synchronism with the draw-off means and the structure to periodically reduce or close off the suction. Preferably, the structure is disposed to provide suction adjacent to the nip of the drawing-off rollers.

Advantageously, the suction is periodically completely closed off.

Preferably, the tuft control means further includes a housing defining a chamber in communication with the passage, and duct means for applying suction to the chamber. The housing is mounted for reciprocal movement in synchronism with the draw-off means and the structure to periodically reduce or close off the suction. The housing may be fixed relative to, and move with, the structure.

Brief Description of the Drawings The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a schematic side elevational view of textile combing apparatus in accordance with an embodiment of the invention; Figure 2 is a view similar to Figure 1 but showing another condition of the apparatus; Figure 3 illustrates a modification for use with very long fibres; and Figures 4 and 5 are views corresponding to Figures 1 and 2 of a further modification.

Preferred Embodiments The illustrated textile combing apparatus 10 includes the usual principal components. These include an input beard delivery mechanism 11 including a shovel plate 12, a feed grid (not shown), and a pair of upper and lower nipper jaws 14,16. Draw-off means in the form of reciprocable apron carriage 20 is reciprocally moveable to draw-off successive tufts from the input beard and to support each tuft. Carriage 20 includes a continuous flat belt 22 with an upper run defining an apron 23, and a pair of upper and lower drawing-off rollers 25,26. Belt 22 passes around the lower drawing-off roller 26.

This roller together with the belt and upper roller 25 thereby define a nip 28 which cyclically moves towards the jaws to draw off a tuft from the combed beard presented by the nipper jaws 14,16. A cylindrical comb 30, often known as the circular comb, is rotatable generally below the nipper jaws and drawing-off rollers, and a rectilinear comb 32, known as the front comb, is moveable to and from a location in front of nip 28.

It will be seen that circular comb 30 and front comb 32 define a combing zone 35 towards which a beard is continually delivered by feed mechanism 11. The cycle of operation is as follows. The current end 8a of the beard 8 is brought down onto the circular comb by nipper jaws 14,16, as shown in Figure 1. As the combed beard is then lifted from the circular comb by the nipper jaws, front comb 32 is brought down, and carriage 20 moves towards the nipper jaws (Figure 2). Rollers 25,26 draw off a tuft 9 from the beard 8 through comb 32 into nip 28 and onto moving apron 23. To facilitate the drawing-off, the nipper jaws 14,16 have been opened so that, following drawing-off, a new beard is ready for presentation to the circular comb. As apron carriage 20 then moves away to the

retracted position of Figure 1, the apron belt 22 is reversed and the newly drawn-off tuft 9 is moved back around under the belt so that the next drawn-off tuft 9' is laid into and onto the preceding tuft. In this way, a newly formed combed web is moved forward along apron 23 for subsequent gathering at the end of the apron to form a sliver.

During the rewind, the tuft tail 42 must be controlled so that it does not strike the circular comb, and so avoid fibre loss as discussed earlier.

To this end, tuft control means 49 is provided under apron carriage 20, in this case including a suction chamber 50 and associated suction tube 54. Structure in the form of a projecting lip 53 extends about lower drawing-off roller 26 to define, between lip 53 and belt 22, a passage or mouth 52 open at 52a to receive tuft tail 42, and in communication with suction chamber 50. Lip 53 is bent at least once at 53a (or alternatively may be curved) and provides a physical barrier between the rewound or rewinding tuft 9 and the circular comb 30, effective to shield the tuft tail 42 from the circular comb.

Suction is applied to chamber 50, and thereby via passage 52 to a region adjacent the nip 28 of the drawing-off rollers 25,26, via a suction tube 54 that is fixed to the frame of the machine. Chamber 50 reciprocally slides back and forth over the open upper end 55 of tube 54, and an opening 56 provided in the floor 58 of chamber 50 to communicate the two is dimensioned so that, in the forward position of the chamber, the opening lies outside the suction tube on a flange 59, and the chamber floor 58 wholly closes over the end 55 of the suction tube, and thereby substantially, or nearly wholly, closes off suction. Other means of operating the suction cycle may of course be substituted.

In the illustrated embodiment, chamber 50 is fixed relative to apron carriage 20 and reciprocates in synchronism with the carriage, whereby passage 52 reciprocates, while open, with the carriage. It will be appreciated that the arrangement constitutes means operable in synchronism with the draw-off means and the shield/lip structure 53 to periodically close off said suction. In an alternative embodiment, the suction chamber is still moveable reciprocally but in a manner independent of, though still in synchronism

with, the motion of the apron carriage. In such an arrangement, the suction chamber is withdrawn from the circular combing zone as the beard is lowered into the circular comb, thus ensuring that the suction does not interfere with the positioning and combing of the beard.

In another modification, the tuft control means 49 may be provided above or adjacent upper drawing-off roller 25 : the tail then rewinds about roller 25.

With the illustrated arrangement, it is possible to achieve very short apron carriage strokes. Very short apron carriage strokes require only slightly longer apron travel to ensure that each tuft is fully drawn off. Even though the apron carriage stroke is reduced by up to 70mm, the apron motion does not need to be substantially altered. This is because in practice the traditional system must draw off almost all of the tuft as these systems are incapable of controlling long fibre tails. A further advantage of short strokes is that it may be possible to reduce the crank setting that controls the apron travel, as a long carriage stroke "steals" some of the apron movement. A reduced crank setting reduces the forces required to drive the apron system.

It will be appreciated that the illustrated arrangement permits very short apron carriage strokes, e.g. of the order of l5mm to 20mm or less, and may be fitted into most existing commercial combs, to achieve enhancement of combing speed and thus production rate.

For longer fibres it may be advantageous to locate slot 56 further away from opening 52a so that the ends are not caught during closure. If relocation of the slot is difficult because of interference with other parts (not shown) of the comb, Figure 3 illustrates a modified suction chamber 50' suitable for use with very long fibres. The modification consists of a central baffle 60 which overlies suction opening 56' and so prevents longer fibres extending through opening 56' and being trapped by the reciprocatory motion.

Figures 4 and 5 schematically show an alternative embodiment of the invention, in which like integers are indicated with like double primed reference numbers. The operational stages respectively correspond to Figures 1 and 2. Here, reciprocable passage 52" is defined between a pair of fore and aft lips or wall segments 53a",53b", of a structure 70 which is hingedly fixed to the frame at 72. Structure 70 reciprocates pivotally back and forth in synchronism with the apron carriage 20". It will be noted that passage 52" remains open, for applying suction adjacent nip 28". The level of suction is varied by a downstream baffle or vent arrangement, as described for example in the aforementioned British patent 1207441.

It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.