WO1994016132A1

WO1994016132A1 - Manufacture of articles from leather

Info

Publication number: WO1994016132A1
Application number: PCT/GB1994/000036
Authority: WO
Inventors: Raymond Peter Irving; Brenda Joyce Irving; Kevin Roberts
Original assignee: Raymond Peter Irving; Brenda Joyce Irving; Kevin Roberts
Priority date: 1993-01-07
Filing date: 1994-01-07
Publication date: 1994-07-21

Abstract

A method of manufacturing articles of leather, comprising taking leather in the form of an elongate strand (22) and knitting the strand into a strip or sheet of material usable to manufacture articles.

Description

Title: Manufacture of Articles From Leather

Description of Invention

This invention relates to the manufacture of articles from leather. The articles may be entire articles or parts thereof, for example items of clothing, accessories such as belts, bags, purses, etc, shoes, or indeed virtually any article which conventionally is made of or incorporates leather in the form of a sheet or strip.

It is broadly the object of the present invention to provide a new method of manufacturing articles of, or incorporating, leather. Other aspects of the invention will be referred to hereafter.

According to one aspect of the invention, we provide a method comprising the steps of taking leather in the form of an elongate strand, and knitting said strand into a strip or sheet of material.

The leather in the form of an elongate strand may be obtained by cutting sheet leather. Preferably the cutting is done in a spiral configuration so as to obtain the longest possible strand from a sheet of leather.

Preferably the strand is cut to a width equal or approximately equal to the thickness of the leather from which the strand is cut, so that the strand is approximately square in cross-sectional shape.

The strand may be subject to a rolling operation to impart to it a round or rounded cross-sectional shape.

In order to give the strand the necessary flexibility and softness to enable it to be knitted, it is desirably subjected to a softening treatment prior to being knitted. Preferably such treatment comprises treatment with a liquid or emulsified fat, oil, or wax.

After knitting the leather to form the strip or sheet material, such material is preferably subjected to a further treatment to seal it so that the material previously used to render it soft and flexible for knitting does not rub off

SUBSTITUTE SHEET onto any clothing etc. which may come into contact with the knitted leather material.

Preferably the sealing treatment is carried out with a cationic urethane sealant.

The knitting may be carried out by hand knitting, using conventional knitting needles and any desired type of stitch. Alternatively, the knitting may be carried out by a knitting machine, an example of which is referred to hereafter.

When hand knitting the leather strand, an appropriate size of knitting needle would be selected to suit the dimensions of the leather strand.

Machine knitting of the strand to form the web material may, by way of example, be carried out on a coarse gauge single jersey open top knitting machine.

To enable such a machine effective to knit leather strands, the provision of certain features has been found to be desirable, if the strand is not to break or otherwise knit unsatisfactorily.

Firstly, the knitting machine preferably is provided with a means positively for feeding the leather strand to the needles of the machine so that the tension in the leather strand as it reaches the needles is minimised. Preferably the tension in the leather strand is less than about 3 gms. It has been found that a tension substantially greater than such a value has an effect on stitch size, and ultimately will lead to breakage of the leather strand.

By way of example, the leather may be fed by guiding it around a substantial part of the periphery of a roller element having a surface capable frictionally of advancing the leather strand, the roller element being driven in accordance with the operation of the knitting machine to provide the required feed of the strand.

Secondly, such a knitting machine preferably is provided with friction reducing means at each needle trick verge to facilitate the pulling of the strand into the recesses between the trick walls by the needles to form successive stitches. Such a friction reducing means preferably comprises a roller element

SUBSTITUTE SHEET rotatably mounted at the top of each trick wall. As described hereafter with reference to the drawings, this also facilitates the forming of the strand into stitch shapes.

Thirdly, the cam means of the machine, which operates the needles, preferably is arranged to hold needles which have already formed stitches by pulling a loop of newly provided strand through the loop of a previously formed stitch, in the positions they have attained for a longer period of time than is normally the case when a fibre yarn is being knitted. By holding, for example, two or three of the needles which have previously formed stitches in such positions, the forming of stitches by following needles does not pull the leather strand out of the preceding stitches.

Further, in a knitting machine, the mechanism which takes the knitted material from the area of the machine in which the knitting is carried out is desirably arranged to provide a constant or substantially constant tension on the knitted material being taken from the needles of the machine.

Although the above features are described hereafter with reference to a type of machine which is a circular machine, it will be appreciated that machines of other type may be made to knit leather strand in accordance with the invention.

According to another aspect of the invention, we provide a knitting machine having one or more of the above set forth features.

According to yet a further aspect of the invention, we provide an article made of or incorporating knitted strip or sheet leather material made by the method according to the first aspect of the invention.

Now to consider the invention in greater detail by way of example, the leather from which the strand used in the invention is obtained must be selected, particularly when it is to be knitted by machine, to give adequate tensile strength. For example, high quality cow hide may provide a strand of approximately 2mm square dimensions (thickness and width) but if a finer strand is required the hide

SUBSTITUTE SHEET from a smaller skinned animal is desirably used. For a very fine strand, kangaroo hide is a desirable material.

For many purposes, UK or other European goat, calf or buffalo hide may provide satisfactory results.

To form the strand from the hide, a spiral cutting process may be utilised. A suitable machine for carrying out such a spiral cutting process is commercially available from KADIC s.p.r.l. of B-2600 Berchamp, Antwerp, Belgium.

As cut from sheet leather by such a machine, a strand is produced which is of square or rectangular cross-section. Such a strand may be subject to a rolling process to form it to a circular or substantially circular cross-sectional shape, and a further machine for carrying such out a rolling process is commercially available from KADIC s.p.r.l. as referred to above.

Desirably the leather strand is treated to soften it and/or lubricate it to render the knitting process more readily operable. By way of example the leather strand may be treated by immersion in an emulsified fat liquor. Alternatively a liquid wax material may be used, or an emulsified oil which is able to be diluted with water or other thinning agent to achieve a viscosity suitable to penetrate the leather to the required degree.

Such treatment of leather prior to knitting gives the potential for a problem of the knitted material presenting a "greasy" characteristic which could transfer to clothing of a person using or wearing an article made from the knitted leather strand. Therefore, as above referred to, the knitted leather material is preferably subjected to a sealing treatment as aforesaid.

The leather strand may be knitted by hand or machine. In the case of hand knitting, conventional knitting needles and any desired type of stitch may be used, the appropriate size of knitting needle being selected to suit the dimensions of the leather strand.

In the case of machine knitting, by way of example by use of a coarse gauge single jersey open top knitting machine, the machine is preferably provided

SUBSTITUTE SHEET with certain features to facilitate the knitting and one or more of such features are illustrated in the accompanying drawing, which shows part of such a machine.

The general construction and mode of operation of such a machine, part of which is shown in the drawing, is well known to an expert in the field of knitting machines and therefore will not be further referred to herein. The illustrated part of the machine is a circumferentially extending portion of a machine cylinder 10 which supports a number of circumferentially spaced vertically orientated latch needles three of which are indicated at 11, 12, 13. Each needle is of known construction and incorporates a shank as indicated at 14 for the needle 11, and a hook 18 and pivoted latch 19, arranged in known manner. The needles are slidable in the vertical direction in respective slots formed on the exterior of the machine cylinder 10, the slots for the three needles 11, 12, 13 being indicated at 15, 16, 17, respectively. Also in known manner, not illustrated, each needle has near the bottom of its shank a cam follower formation which engages with cam surfaces formed in a cam member or structure 20 which in use of the machine undergoes relative movement relative to the cylinder 10, circumferentially about the cylinder, in the direction of arrow 21. Either the cam arrangement or the cylinder may move to provide this relative circumferential movement. The effect is that successive needles are raised and lowered to carry out knitting on a strand fed to the machine.

The drawing shows the three needles 11, 12, 13 in successive positions they assume, under the control of the cam 20, in use. Needle 11 is raised to its highest position above the edge of cylinder 10 where its hook can receive the new strand supplied at 22. As it has been raised to such position, the previously formed loop has moved downwardly away from the hook 18 to open the latch 19 and rest on the upper portion of the shank of the needle.

After having been raised to such position, the needle is lowered and in the drawing the needle 12 has been thus lowered. The hook 18 of such needle pulls the strand 22 downwardly and as the needle passes through the previously formed loop the latch is closed. The needle 13 has been further lowered and has

SUBSTITUTE SHEET reached its lowermost position in which the newly supplied strand has been pulled right through the respective loop previously formed by such needle, the hook of the needle having been lowered beneath the top of the cylinder 10 into the recess defined between adjacent trick walls 24.

It is the pulling of the newly supplied strand downwardly between the trick walls which presents a particular problem when a leather strand is being knitted. Problems arise from the thickness and relative inflexibility of the leather strand, and the first expedient adopted to help overcome such problems is that the strand supplied at 22 is preferably supplied at a tension as low as possible and preferably zero. To do this, a knitting machine is preferably provided with a means for feeding the strand in accordance with the operation of the knitting machine. Such a feeding means may be as described above.

Secondly, a respective friction-reducing roller element 25 is provided at the top of each trick wall 24. Such provision renders it easier for the leather strand to be pulled down over the verge region at the top of each trick wall, into the looped shape shown at the needle 13.

Thirdly, the cam member 20 of the machine is arranged to hold the preceding needles, beyond the needle 13, in the lowermost positions as shown for needle 13 longer than would be the case if the machine were knitting a fibre yarn. Preferably the two or three needles preceding the needle 13 are thus held before such needles are again raised to release the stitch formed thereby and approach the position in which needle 11 is shown ready to receive fresh strand.

A circular knitting machine such as described above produces the knitted leather material in the form of a sheet in tubular form. Such form of material is useful for manufacturing articles incorporating elements of tubular configuration, e.g. bags, purses or the like, or material in tubular form may be used flattened into a double thickness of material, e.g. for belts. Knitting machines of other type may of course be adapted to knit leather strand. For example a flat bed machine may be used.

SUBSTITUTE SHEET Knitted leather strip or sheet material may be used to form all or part of articles which conventionally are made of strip or sheet leather. Examples of such articles include braces, shoe uppers, bags, purses, watch straps, waistcoats, belts, and so on.

Knitted leather material according to the invention may constitute entire articles or parts thereof. In the example of a belt, the knitted leather material may constitute the entire belt including a part at one end to which a buckle is attached and a part at the other end which co-operates with the buckle. Alternatively the material according to the invention may form a part only of the belt to which parts to which the buckle is connected and which co-operate with the buckle are themselves connected. Such other parts may be of leather sheet material, or any other appropriate material. Analogous techniques may be used for the manufacture of other articles.

As above referred to, the leather strand may be knitted by hand using any conventional knitting stitch or combination or sequence of stitches according to the desired pattern or style of the article or part article which is being manufactured. Conventional knitting needles may be used, and it is intended that within the scope of the term "knitting" we include the knitting technique known as crochet in which a hooked needle or needles is used. Conventional knitting techniques such as casting off may be used, as appropriate.

In certain circumstances, synthetic substitutes for natural leather may be utilised in the method of the present invention, and where appropriate the term "leather" is intended to include such substitutes.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

SUBSTITUTE SHEET

Claims

1. A method comprising the steps of taking leather in the form of an elongate strand, and knitting said strand into a strip or sheet of material usable for manufacturing articles.

2. A method according to Claim 1 wherein said elongate strand is obtained by cutting sheet leather in a spiral configuration.

3. A method according to Claim 2 wherein the strand is cut to a width equal or approximately equal to the thickness of the leather, so that the strand is approximately square in cross-sectional shape.

4. A method according to Claim 3 comprising subjecting said strand to a rolling operation to impart to it a round or rounded cross-sectional shape.

5. A method according to any one of the preceding claims comprising subjecting the leather strand to a softening and/or lubricating treatment prior to knitting it.

6. A method according to Claim 5 wherein said treatment comprises treatment with a liquid or emulsified fat, oil or wax.

7. A method according to Claim 5 or Claim 6 further comprising subsequently treating the strip or sheets of knitted leather material with a sealant.

8. A method according to Claim 7 wherein said sealant is a cationic urethane sealant.

SUBSTITUTE SHEET

9. A method according to any one of the preceding claims wherein said knitting step is hand knitting.

10. A method according to any one of Claims 1 to 8 wherein said knitting step is carried out by a knitting machine.

11. A method according to Claim 10 wherein said knitting machine is a coarse gauge single jersey open top knitting machine.

12. A method according to Claim 10 or Claim 11 comprising feeding the leather strand to the needles of the machine under a tension as low as possible.

13. A method according to Claim 12 wherein said tension is less than about 3 gms.

14. A method according to Claim 12 or Claim 13 comprising feeding the leather around a substantial part of the periphery of a roller element having a surface capable frictionally of advancing the leather strand, and driving the roller element in accordance with the operation of the knitting machine to provide the required feed of the strand.

15. A method according to Claim 11, or any one of Claims 12 to 14 appendant thereto, comprising holding needles which have already formed stitches, by respectively pulling a loop of newly provided strand through the loop of a previously formed stitch, in the positions they have thus attained for sufficiently long that the forming of stitches by following needles does not pull the leather strand out of the preceding stitches.

SUBSTITUTE SHEET

16. A method according to any one of Claims 10 to 15 comprising taking the knitted material from the needles of the machine under a substantially constant tension.

17. An article made of or incorporating knitted strip or sheet leather material made by the method according to any one of the preceding claims.

18. An article according to Claim 17 which is a bag, purse, belt, watch strap, or waistcoat.

19. A knitting machine for carrying out the knitting step of a method according to Claim 10 or any claim appendant thereto, comprising means positively for feeding the leather strand to the needles of the machines so that the tension in the strand as it reaches the needles is minimised.

20. A knitting machine according to Claim 19 comprising a roller element having a surface capable frictionally of advancing the leather strand, means for guiding the leather strand around a substantial part of the periphery of the roller element, and means for driving the roller element in accordance with the operation of the knitting machine to feed the strand.

21. A knitting machine for carrying out the knitting step of the method according to Claim 10, or according to Claim 19 or Claim 20 comprising means for providing a constant or substantially constant tension on the knitted material being taken from the needles of the machine.

22. A knitting machine for carrying out the knitting stage of the method according to Claim 10, or according to any one of Claims 19 to 21, which is a coarse gauge single jersey open top knitting machine.

SUBSTITUTE SHEET

23. A knitting machine according to Claim 22 comprising friction-reducing means at each needle trick verge, for facilitating the pulling of the strand into the recesses between the trick walls by the needles to form successive stitches.

24. A knitting machine according to Claim 23 wherein said friction- reducing means comprises a roller element rotatably mounted at the top of each trick wall.

25. A knitting machine according to any one of Claims 22 to 24 wherein cam means of the machine, for operating the needles thereof, is arranged to hold needles which have already formed stitches, by respectively pulling a loop of newly provided strands through the loop of a previously formed stitch, in the positions they have thus attained for sufficiently long to prevent the forming of stitches by following needles from pulling the leather strand out of the preceding stitches.

26. A method substantially as hereinbefore described.

27. A knitting machine substantially as hereinbefore described with reference to the accompanying drawing.

28. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.

SUBSTITUTE SHEET