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Patent Searching and Data


Title:
FIBRE PROCESSING
Document Type and Number:
WIPO Patent Application WO/1994/024348
Kind Code:
A1
Abstract:
Metallic card-clothing wire (1) includes a plurality of teeth (2) supported by a base (4). Each tooth (2) includes a leading surface (6), side surfaces (8) and a rear surface (10). The leading surfaces (6) are arranged, in use, to initially engage fibre to be processed, for example, by opening, stretching, combing and/or parallelising. The leading surface (6) of the wire (1) is treated so as to adjust its roughness and thereby adjust the fibre processing ability of the wire. It has been found that increasing the roughness of the leading surface of each tooth increases the holding power, stretching power or carding intensity of the wire in the same way that decreasing the size of the leading angle alpha affects these parameters. In another embodiment described, the leading surface may also be treated to renew worn teeth.

Inventors:
SCHMOLKE KARL-HEINZ (DE)
Application Number:
PCT/EP1994/001025
Publication Date:
October 27, 1994
Filing Date:
March 30, 1994
Export Citation:
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Assignee:
ENGLISH CARD CLOTHING (GB)
SCHMOLKE KARL HEINZ (DE)
International Classes:
D01G15/88; D01H4/32; (IPC1-7): D01H4/32; D01G15/88
Foreign References:
DE4038352A11992-06-04
GB1144534A1969-03-05
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Claims:
CLAIMS
1. A fibre engaging element for a fibre processing apparatus, the element including a leading surface and other surfaces downstream thereof, wherein the frictional character of the leading surface is different to the frictional character of other surfaces downstream thereof.
2. A fibre engaging element according to Claim 1, wherein the leading surface is adapted to exert, in use, a greater force on fibre than the force exerted on fibre by at least some surfaces of said fibre engaging element downstream of the leading surface.
3. A fibre engaging element according to Claim 1 or Claim 2, wherein the roughness of the leading surface of the fibre engaging element is greater than the roughness of at least some surfaces of said fibre engaging element downstream of the leading surface.
4. A fibre engaging element according to any preceding claim, wherein substantially the whole of said leading surface has substantially the same frictional character.
5. A fibre engaging element according to any preceding claim, wherein said other surfaces downstream of the leading surface include a side surface of the fibre engaging element which extends transversely to said leading surface, wherein substantially the whole area of said side surface has substantially the same frictional character.
6. A fibre engaging element according to any preceding claim, wherein said other surfaces downstream of the leading surface include an end surface, wherein substantially the whole area of said end surface has substantially the same frictional character.
7. A fibre engaging element according to any preceding claim, in the form of a sawtoothed shaped tooth or a needle tooth.
8. A fibre engaging element according to any preceding claim, for a fibre processing apparatus in the form of an opening roller of an open end spinning machine or of a carding machine.
9. Cardclothing which includes a plurality of fibre engaging elements according to any of Claims 1 to 8 supported on a base.
10. A ring for a fibre processing apparatus, the ring including a plurality of fibre engaging elements according to any of Claims 1 to 8.
11. A method of adjusting the carding intensity and/or holding power of a fibre engaging element of a fibre processing apparatus, the method comprising adjusting the frictional character of a leading surface of the fibre engaging element relative to the frictional character of other surfaces of said fibre engaging element downstream of the leading surface.
12. A method according to Claim 11, wherein the fibre engaging element is as described in any of Claims 1 to 8.
13. A method of renewing a fibre engaging element of a fibre processing apparatus, the method comprising adjusting the frictional character of a leading surface of the fibre engaging element relative to the frictional character of other surfaces of said fibre engaging element downstream of the leading surface.
Description:
FIBRE PROCESSING

This invention relates to fibre processing and particularly, although not exclusively, to a fibre engaging element for an open-end spinning machine and/or for a carding machine.

The efficiency of fibre processing for example, fibre opening, combing, stretching and/or parallelisation in fibre processing apparatus, for example, in open-end spinning machines and carding machines is of paramount importance, and much development work has been undertaken with a view to optimising the efficiency. More particularly, much development work has been directed to the design and quality of metallic card clothing wires which have teeth which serve as fibre engaging elements in the machines. For example, the teeth of the metallic card clothing wire have become more delicate and their population greater. Furthermore, referring to Figures 1 and 2 of the accompanying diagrammatic drawings which figures show a portion of metallic card clothing wire in side elevation and in cross-section respectively, the leading or front angle α of a tooth 2 has become more acute and the width ■, b w " of base 4 has become less. The present trend as regards the design of card clothing wire for high production carding applications is to provide very short wire heights "h", an acute leading angle α and wire pitches "p" in the range of about 1.3 to 2.0 mm.

It is known that the leading angle α of the tooth 2 influences the holding ability of the tooth. In the past, the angle was generally in the range of about 75° to 80°. More recently, angle α is generally in the range of about 60° to 70°, or possibly α may be even more acute. This reduction in the size of the leading angle α has been

found to increase holding power and carding intensity (and hence carding power) since fibres have been found to be stretched out to a greater extent between, for example, the flats of a card and the card-clothing wire.

However, there is a problem in that, if the leading angle is too small, the holding power and, therefore, the carding intensity becomes too great and fibres may become broken during fibre processing.

The size of angle is generally selected according to the type of fibre being processed. For example, in practice, the leading angle α is greater when synthetic fibres are being processed, in comparison to when cotton fibres are being processed, since cotton fibres are typically more tangled and have greater surface roughness in comparison to synthetic fibres.

This invention is based on the discovery that the frictional character of the leading surface of fibre engaging elements affects the fibre processing ability of the fibre engaging elements in a similar way to the effect of adjusting the leading angle α.

According to a first aspect of the present invention, there is provided a fibre engaging element for a fibre processing apparatus, the element including a leading surface and other surfaces downstream thereof, wherein the frictional character of the leading surface is different to the frictional character of other surfaces downstream thereof.

The leading surface of the fibre engaging element is suitably a surface of the element which is arranged, in use, to initially engage fibre to be processed. The

leading surface is suitably arranged to face, in use, the direction of travel of the fibre engaging element relative to fibre to be processed.

The leading surface of said fibre engaging element may have a width in the range about 0.01 mm to 0.5 mm. The height of said element may be in the range about 0.1 mm to 10 mm.

Downstream surfaces of the fibre engaging element suitably include side surfaces of the element which side surfaces are adjacent to said leading surface. Said side surfaces preferably extend in a direction transverse to the extent of said leading surface. Preferably, said leading surface and said side surfaces are disposed substantially perpendicularly to one other. A said downstream surface of the fibre engaging element may include an end surface of said element. Said end surface is preferably adjacent to said side surfaces and preferably faces in a generally opposite direction to said leading surface.

Preferably, the leading surface is adapted to exert, in use, a greater force, for example, a greater frictional force on fibre than the force exerted on fibre by at least some surfaces of said fibre engaging element downstream of the leading surface.

Preferably, the roughness of the leading surface of the fibre engaging element is greater than the roughness of at least some (preferably all) surfaces of said fibre engaging element downstream of the leading surface.

Preferably, substantially the whole of said leading surface has substantially the same frictional character.

Preferably, the roughness of e leading surface is substantially uniform across substantially the whole extent thereof. Preferably, the roughness of the leading surface is selected in dependence upon the size of the leading angle ( ) of said fibre engaging element.

Preferably, substantially the whole of said side surfaces has the same frictional character. Preferably, the roughness of said side surfaces is substantially uniform across the whole extent thereof.

Preferably, substantially the whole of said end surface has the same frictional character. Preferably, the roughness of said end surface is substantially uniform across the whole extent thereof.

Said fibre engaging element may consist of a saw¬ tooth-shaped tooth or a needle tooth.

A support member is preferably provided for supporting said fibre engaging element. Preferably, said support member supports a plurality of said fibre engaging elements which are preferably substantially identical. Said support member may comprise a metallic base of card- clothing wire or a flexible foundation of a laminated material. The base may include an upwardly facing surface which may be arranged to engage fibre in use. The frictional character of said upwardly facing surface may be the same or different to the frictional character of said leading surface. Said frictional character of said upwardly facing surface may be the same or different to the frictional character of said side surfaces and/or end surface.

- D -

The fibre engaging element may be for a fibre processing apparatus in the form of an opening roller for an open-end spinning machine or for a carding machine. Preferably, the fibre engaging element is for a fibre processing apparatus in the form of an opening roller for an open-end spinning machine.

The invention extends to a length of card-clothing wire including a plurality of fibre engaging elements and a base as described according to said first aspect.

The invention further extends to a ring for a fibre processing apparatus of, for example, an open-end spinning machine, the ring including a plurality of fibre engaging elements as described according to said first aspect.

According to a second aspect of the present invention, there is provided a method of adjusting the carding intensity and/or holding power of a fibre engaging element of a fibre processing apparatus, the method comprising adjusting the frictional character of a leading surface of the fibre engaging element relative to the frictional character of other surfaces of said fibre engaging element downstream of the leading surface.

The fibre engaging element may be arranged as described according to said first aspect.

The frictional character of said fibre engaging element may be adjusted by mechanical means, for example, by sandblasting the leading surface or by knurling, grooving or cutting the leading surface, or by chemical means. In one embodiment, the leading surface may be coated by spraying thereby to adjust its relative frictional character.

According to a third aspect of the present invention, there is provided a method of renewing a fibre engaging element of a fibre processing apparatus, the method comprising adjusting the frictional character of a leading surface of the fibre engaging element relative to the frictional character of other surfaces of said fibre engaging element downstream of the leading surface.

The fibre engaging element may be renewed in the method described according to said second aspect. For example, the leading surface may be re-roughened, after its normal useful life is passed. Also, a fibre engaging element which includes random wear marks on its leading surface may be renewed by re-roughening the leading surface.

The adjustment of the relative frictional character of the leading surface of a fibre engaging element as described in said second and third aspects of the present invention may be undertaken when the fibre engaging element is mounted on a fibre processing apparatus or with the fibre engaging element detached from a fibre processing apparatus.

Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

Figure 1 is a side elevation of a portion of metallic card-clothing wire;

Figure 2 is a vertical cross-section through the card-clothing wire of Figure 1;

Figure 3 is a perspective view of a portion of the metallic card-clothing wire of Figures 1 and 2;

Figure 4 is a perspective view of a tooth of card- clothing wire which tooth has random wear marks; and

Figure 5 is a perspective view of the tooth of Figure 4 after roughening of the leading surface of the tooth.

Metallic card-clothing wire 1 includes a plurality of teeth 2 supported by a base 4 having an upwardly facing base surface 5. Each tooth 2 includes a leading surface 6, side surfaces 8 and a rear surface 10. The leading surfaces 6 are arranged, in use, to initially engage fibre to be processed, for example, by opening, stretching, combing and/or parallelising.

Reference notation used in the figures is as follows: "h" represents wire height; "b v " represents wire base width; "p" represents the pitch of the teeth; "d" represents the depth of cut; "a" represents the leading or front angle; "β" represents the back angle; and "b,, 11 represents the base height.

In previously known card-clothing wire, the roughness of all surfaces of the teeth is identical. However, in the card-clothing wire of the present invention, the leading surface 6 of the wire 1 is treated so as to adjust its roughness and thereby adjust the fibre processing ability of the wire.

Investigations have been made into the effects on carding of varying the roughness of the leading surfaces

6 of card-clothing wire (whilst maintaining the roughness of the side surfaces 8, rear surface 10 and base surface

- 3 -

5 constant) and of varying the size of the leading angle .

The "roughness" of a metal surface is measured as an R. valve, wherein R. is the average distance between the peaks and troughs of the metallic surface as described in, for example, "Metrology and Precision Engineering" at page

134.

Table 1 (below) lists characterising data of card- clothing wire investigated.

TABLE 1

Card-clothing Size of R a of leading R a of side R a of rear R a of base wire of leading angle surfaces (6) surfaces (8) surfaces surfaces (5) Example No. (α) (10)

1 80° 6.0 μm 1.5μm 1.5μm 1.5μm

2 60° 1.5μm 1.5μm 1.5μm 1.5μm

10 3 80° 3.Oμ 1.5μm 1.5μm 1.5μm

4 70" 1. bμm 1.bμm 1. bμm 1. bμm

The card-clothing wire of Examples 1 and 3 is in accordance with the present invention. The card-clothing wire of Examples 2 and 4 is known wire included for comparison purposes.

It has been found that the holding power, stretching power or carding intensity of the wires of Examples 1 and 2 is approximately the. same.

Also, it has been found that the holding power, stretching power or carding intensity of the wires of Examples 3 and 4 is approximately the same. *

It should be noted from the above results that increasing the roughness of the leading surfaces of the wire increases the holding power, stretching power or carding intensity of the wire in the same way that decreasing the size of the leading angle a is already known to affect these parameters. It is believed to be important that side surfaces 8 and/or rear surface 10 are relatively smooth so that fibres can be relatively easily disengaged from the card-clothing wire during fibre processing.

One advantage resulting from the present invention is that a single type of wire may be cut, for example having a leading angle of 80°, and subseguently the roughness of the leading surfaces of the wire may be adjusted according to the type of fibre to be processed, thereby to adjust the holding power, stretching power or carding intensity of the wire to a desired level.

For example, whereas previously the teeth of an opening roller for an open-end spinning machine may have had a leading angle α of 65° when running cotton and 75° when running synthetics, the desired holding power can be

obtained using wire having a leading angle of 80° and adjusting the roughness of the leading surface. The roughness of the leading surface may be adjusted to achieve equivalence to all desired leading angles.

The roughness of the leading surfaces of the teeth of a one-piece solid opening roller of an open-end spinning machine may to be adjusted in the manner described above.

Also, the roughness of the leading surface of teeth of carding apparatus may be adjusted in the manner described.

Another advantage which may result from the present invention, is that the wires (whether cylinder wire, doffer wire, licker-in wire, wire of an opening roller for open end spinning or of combing segments or any other parts in textile machines which include wires or needles) need not be re-sharpened or reground after they have become worn - the leading surfaces of the wires need only be re-roughened.

This advantage manifests itself in, for example, open-end spinning, where removable rings carry card- clothing wires. Previously, when the card-clothing of such rings became worn, the rings would be discarded and new rings used. However, the rings may now be renewed by re- roughening the leading surfaces of the teeth of the ring. Significant cost savings may be achieved by such actions.

The roughening of the leading surfaces of teeth may be carried out by mechanical or chemical means or by spray coating. In one mechanical means of roughening, the leading surface may be sand-blasted to effect the desired degree of roughening.

Another factor which adversely affects yarn quality is the presence of random wear marks 25 (Figure 4) on the

leading surface 6. By re-roughening the leading surface 6, the wear marks 25 are also roughened so that the teeth ' 2 may function like new, unworn and unmarked teeth.

Previously, it was common to regrind metallic card- clothing of a carding machine, after the teeth of the card-clothing wire had become worn. Such regrinding involves disassembling parts of the machine and using a transverse grinder to regrind the points of the card- clothing wire. However, by re-roughening the leading surfaces of the teeth of the card-clothing wire, the teeth may effectively be renewed so that the carding ability of such renewed teeth may be comparable to the carding ability of new teeth. Thus, by re-roughening the leading surface, the necessity to regrind the teeth may be removed or at least reduced.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification

(including any accompanying claims, abstract and drawings) , may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated

otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.