WO1999005352A1

WO1999005352A1 - Improvements in tyre manufacture

Info

Publication number: WO1999005352A1
Application number: PCT/GB1998/002197
Authority: WO
Inventors: Eric Holroyd; Colin Holroyd
Original assignee: Holroyd Associates Limited
Priority date: 1997-07-23
Filing date: 1998-07-22
Publication date: 1999-02-04
Also published as: GB2327435A; GB9715458D0; AU8454798A

Abstract

Apparatus for manufacturing fabric comprises a pair of parallel and axially rotatable spindles (42), each of which has a helical channel for training cord therealong. The spindles (42) are rotatable in unison. The apparatus further comprises a dispensing arm (36, 38) rotatable around the spindles for winding cord around the spindles, the dispensing arm (36, 38) comprising two dispensers (48) spaced radially outwardly of the spindles, each dispenser being operative to deliver cord to be wound around said spindles.

Description

Title: Improvements in Tyre Manufacture

The present invention concerns improvements in tyre manufacture, particularly the manufacture of radial tyre carcass reinforcement fabric.

The carcass reinforcement of a radial tyre comprises one or more plies of weftless fabric which, in the shaped tyre, has all the reinforcement cords lying in substantially radial planes so that each cord of the fabric extends from tyre bead to tyre bead around the tyre cross section.

Various different methods are known for producing a ply of fabric as described above. U.K. Patent Applications GB-A-2212441 and GB-A-2212529 describe a system whereby a tape having longitudinally extending cords is wrapped helically around a mandrel. The wound tape is then cut transversely to produce a flat sheet having reinforcing cord extending thereacross. The flat sheet can then be used as a ply in tyre manufacture.

U.K. Patent 995613 describes a similar system whereby the wound tape is continuously fed off the mandrel and through cutters. The strips formed thereby have cords running transverse thereof and they can be used as ply fabric in tyre manufacture.

U.K. Patent Application GB-A-2132573 describes a method for manufacture of a tyre ply material, in which a cord is wound helically around a cylindrical former. The winding is then covered by a helical winding of uncured rubber tape, and then the composite winding is cut longitudinally of the former to produce a rectangular piece of ply material.

In each of the above cases, the strength of the ply fabric formed by the systems described relies on the strength of joints between lapped tape windings.

U.K. Patent Application GB-A-2159185 describes apparatus and a method of manufacturing reinforcing fabric ply for pneumatic tyres, comprising a pair of parallel spindles rotating in the same direction, each spindle being surrounded by a helical sleeve rotating in the opposite direction to the spindles. An arm having a bobbin at one end thereof winds cord onto the two spindles, and a fabric is created thereby. The fabric is moved off of the spindles by means of the travel of the cord along the helical sleeves.

UK Patent 1596332 describes the manufacture of a material having weft and warp fibres. Such material would not suitably be manufactured by a winding mechanism, because the weft would interfere with the winding mechanism.

UK Patent" 1517748 describes a highly complicated arrangement for winding a ply fabric without leading to twisting. UK Patent 1419728 describes a yarn delivery mechanism which can be employed in the mechanism illustrated in UK Patent 1517748.

Finally, UK Patents 1301788 and 1126530 describe a method of manufacturing ply by winding from stationary bobbins.

According to the invention, there is provided apparatus for manufacturing fabric, the apparatus comprising a pair of parallel and axially rotatable spindles, each spindle having a helical channel for training cord therealong, said spindles being rotatable in unison, and a dispensing arm rotatable around the spindles for winding cord around said spindles, the dispensing arm comprising two dispensers spaced radially outwardly of the spindles, each dispenser being operative to deliver cord to be wound around said spindles.

In that way, a fabric may be achieved which has a favourably dense constaiction, being formed of a double helical structure.

The two dispensers may be diametrically opposed relative to the axis of rotation of the dispensing arm. That is advantageous in that the arm will be balanced for rotation, thereby reducing wear on bearings. Preferably the apparatus comprises a calender, said calender comprising two rollers rotatable on axes substantially perpendicular to the axes of rotation of the spindles, the rollers defining a nip, and coating means for coating fabric passing through the nip of the calender with a layer of elastomeric material, wherein each of the spindles has a distal end towards which cord is trained in use, each distal end being directed into the nip between the rollers, such that the entire width of a fabric wound on the spindles in use is fed into the calender.

In that way, cord wound on the spindles is directly introduced into the calender for coating thereof across the entire width thereof.

The distal ends of the spindles may be tapered. In that way, cord wound on the spindles can be introduced deeper into the nip of the calender. Furthermore, the taper allows the wound cord to be removed from the spindle more easily.

The distal ends of the spindles may be trapped in the nip of the calender. That allows an advantageous positive location of the spindles in the nip of the calender.

In a preferred embodiment, the calender comprises four rollers, including two inner rollers constituting the two above described rollers defining the nip therebetween and two outer rollers outside said two inner rollers, each of said outer rollers defining a nip with a respective inner roller.

Preferably, the coating means comprises means for dispensing elastomeric material to each of the nips defined between a respective inner roller and outer roller, such that elastomeric material can be introduced onto the surface of each inner roller for transfer to fabric passing through the calender.

In a preferred embodiment of the invention, the apparatus comprises pressing means arranged to receive coated fabric from said calender for pressing said fabric.

Preferably, tension relieving means is provided between said calender and said pressing means.

In a preferred embodiment, the apparatus, having a calender as defined above, comprises a second calender for receiving coated fabric and applying a liner thereto.

The spindles in accordance with the invention may be tubular, such that a bead wire can be delivered from the distal end of each of said tubular spindles in use.

In that way, bead wires can be interlaced with the cord at each edge of the ply, thereby providing a more integrated product. Generally, further bead wires will be added to the construction of the tyre, but the bead wire within the ply is useful for purposes of location.

The dispensing arm in accordance with any of the aspects of the invention described above is preferably rotatable on an axis parallel to the spindle axes.

The dispensing arm and the spindles are preferably rotatable in the same sense.

Further aspects and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention, with reference to the accompanying drawings, in which:

Figure 1 is a side elevation of a ply manufacturing station including a winding apparatus according to a specific embodiment of the present invention;

Figure 2 is a side elevation similar to that illustrated in figure 1 of another ply manufacturing station;

Figure 3 is a detail plan of the winding apparatus illustrated in figures 1 and 2; and

Figure 4 is a schematic view of the winding apparatus of preceding drawings showing a preferred mode of operation. Referring to figure 1, a ply forming station 10 comprises a ply winding apparatus 12, a rubberising calender 14, a press 16, a lining calender 18 and a trimmer 20. Those components are aligned in the order stated above.

The winding apparatus 12 is described more particularly with reference to figure 3. A turret 22 comprises a base 24 and front and rear upstanding members 26, 28. A generally horizontal axle 30 is journalled in the upper end of the rear upstanding member 28, and extends towards the front of the turret 22.

A tubular sleeve 32 is arranged coaxially with the axle 30, and is journalled, via bearings 34, in the front- upstanding member 26. The sleeve 32 is rotatable relative to the turret 22. At the front end of the sleeve 32, a pair of arms 36 extend radially outwardly. The arms 36 are diametrically opposed. Each arm 36 has a radial portion, and at the end of the radial portion a portion at right angles thereto, i.e. parallel with the axis of rotation of the sleeve 32. The axial portion extends forward of the turret 22.

At the rear end of the sleeve 32, a similar pair of arms 38 are mounted thereon; they are oriented generally towards the rear of the turret 22. The arms 36, 38 are generally coplanar.

A front plate 40 is mounted on the front end of the axle 30, adjacent the front end of the sleeve 32. The front plate 40 is generally planar and is oriented in a plane at right angles to the axle 30. The front plate 40 comprises a pair of spindles 42 extending forwardly of the front plate 40 and parallel to the axle 30. The spindles 42 are equally spaced either side of the axle 30.

Each spindle 42 has a helical groove in the surface thereof. Each spindle is arranged to rotate relative to the plate; drive to the spindles 42 is conducted via shafts through the axle 30 and side shafts 44.

Each of the arms 38 has a radially inwardly extending pin 46 on which is provided a bobbin 48 of cord. The sleeve 32 has a pair of parallel axial channels 50, diametrically opposed about the axis of the sleeve 32, and along which cord is conducted from respective bobbins 48 to the front of the sleeve 32 and therefrom to the tips of the arms 36.

The arms 36, 38 and the channels 50 are all provided with pulley wheels 52 to assist the passage of cord to the tips of the arms 36.

The sleeve 32 is rotated by a drive motor situated on the turret 22. The drive is transferred by means of a belt 54 riding in a flanged wheel 56. On rotation of the sleeve 32, cord is dispensed from the tips of the arms 36, and wound around the spindles 42. The cord will ride in the helical grooves, and by rotation of the spindles, the wound cords will traverse away from the front plate towards the ends of the spindles 42.

The rubberising calender 14 is arranged to receive wound cord from the winding apparatus 12. The calender 14 comprises upper and lower inner rollers 60, 62, arranged in parallel. The inner rollers 60, 62 are oriented at right angles to the spindles 42, and define a nip 64 into which the ends of the spindles 42 extend. Hence, cords wound on the spindles are delivered into the nip 64. The inner rollers 60, 62 in use rotate in opposite directions so as to draw the wound cord from the spindles and into e nip 64.

Each of the inner rollers 60, 62 has a respective outer roller 66 arranged thereagainst. Hence, the rubberising calender 14 is known as a "four bowl" calender. A delivery outlet 68. is arranged between each inner and outer roller combination 60, 66, 62, 66, and out of which is delivered pellets of elastomeric material. Those pellets are squeezed between the inner and outer roller and become a coating on the surface of the inner roller. That coating is transferred in use to either side of the wound cord passing through the nip 64 between the inner rollers 60, 62.

The calender 14 further includes an accumulator 69 to which the coated cord is passed after exiting the nip 64. The accumulator prevents minor variations in speed in the process from causing ply to break. The press 16 comprises a top plate 70 and a bottom plate 72, between which successive portions of the coated wound cord exiting the rubberising calender 14 are pressed. The effect of that is to push the elastomeric material through the windings of the wound cord to achieve strike through. In that way, a ply material having cord embedded therein is formed.

The lining calender 18 is situated to receive ply from the press 16. The lining calender 18 is a three bowl calender, in that it comprises three rollers 74, 76, 78 arranged one above another in parallel. The ply is passed between the upper two rollers 74, 76, in use. The lowest roller 78 is served by a delivery outlet 80 which deposits pellets of elastomeric material between the lowest roller 78 and the roller 76 adjacent thereto. The deposited material forms a layer on the adjacent roller 76 which is subsequently transferred to the ply passing through the calender 18. Accordingly, the calender 18 forms a lining layer on the ply.

The trimmer 20 comprises a pair of cutters 82 arranged one each side of a roller track 84 . The cutters trim each edge of the ply passing therethrough, and so produce a parallel sided product. A trimming removal duct 86 is arranged to remove trimmings; trimmed elastomeric material can be recycled for future use.

The station illustrated in figure 2 is similar to that illustrated in figure 1. Those parts thereof which are common to the two stations are given the same reference numeral and will not be described further.

The station 100 of figure 2 includes a ply winding apparatus 12, a rubberising calender 14, a press 16, a trimmer 20 and a slitter 90. Those components are aligned in the order stated above. It will be appreciated that the station 100 does not include a lining calender 18, but that one could be provided if necessary.

Once ply has exited the trimmer 20, it enters the slitter 90. The slitter comprises a plurality of parallel slitting heads 92 arranged across the width of the ply to draw off a plurality of parallel strips of the ply material. Therefore, for convenience a number of small components may be produced out of a wide strip of ply material. The slitter 90 comprises a plurality of transporters 94 to separate and transport away the strips formed thereby.

It will be appreciated that the slitter is not an essential element of the invention, and is only used in certain circumstances where a particular tyre construction is required. In one such case, a slitter is used on a second of two ply manufacturing stations provided in a ply assembly plant.

Figure 4 shows a winding apparatus in schematic form. For guidance, the components of the winding apparatus, and portions of a calender, have been labelled with reference numerals appropriate to the specific embodiment described above.

Figure 4 shows some further features of the specific embodiment of the invention. The spindles 42 of figure 4 are tubular, and bead wire is delivered down the tube centres. In that way the ply formed by the apparatus of figure 4 may incorporate bead wire at each edge thereof. Clearly, with bead wire being incorporated at each edge of the ply, the trimmer will need to be finely adjusted or omitted altogether.

By providing two arms 36 on the winding apparatus 12, it is possible to double the rate of ply production for a given speed of arm rotation. For instance, an arm rotation speed of 600 rpm of the present apparatus leads to a rate of ply production which is only attainable with apparatus having one arm by running that single arm at 1200 rpm. Such a high speed could be unavailable having regard to mechanical limitations of the apparatus.

Claims

1. Apparatus for manufacturing fabric, the apparatus comprising a pair of parallel and axially rotatable spindles (42), each spindle (42) having a helical channel for training cord therealong, said spindles (42) being rotatable in unison, and a dispensing arm (36, 38) rotatable around the spindles (42) for winding cord around said spindles (42), the dispensing arm (36, 38) comprising two dispensers (48) spaced radially outwardly of the spindles (42), each dispenser being operative to deliver cord to be wound around said spindles (42).

2. Apparatus according to claim 1 wherein the two dispensers (48) are diametrically opposed relative to the axis of rotation of the dispensing arm (36, 38).

3. Apparatus according to claim 1 or claim 2 and further comprising a calender (14), said calender (14) comprising two rollers (60, 62) rotatable on axes substantially perpendicular to the axes of rotation of the spindles (42), the rollers defining a nip (64), and coating means (66, 68) for coating fabric passing through the nip (64) of the calender (60, 62) with a layer of elastomeric material, wherein each of the spindles (42) has a distal end towards which cord is trained in use, each distal end being directed into the nip (64) between the rollers, such that the entire width of a fabric wound on the spindles in use is fed into the calender.

4. Apparatus according to claim 3 wherein the distal ends of the spindles (42) are tapered.

5. Apparatus according to claim 4 wherein the distal ends of the-spindles are trapped in the nip of the calender.

6. Apparatus according to any one of claims 3 to 5 wherein the calender comprises four rollers (60, 62, 66), including two inner rollers (60, 62) constituting the two above described rollers defining the nip therebetween and two outer rollers (66) outside said two inner rollers, each of said outer rollers defining a nip with a respective inner roller.

7. Apparatus according to claim 6 and wherein the coating means comprises means (68) for dispensing elastomeric material to each of the nips defined between a respective inner roller (60, 62) and outer roller (66), such that elastomeric material can be introduced onto the surface of each inner roller for transfer to fabric passing through the calender.

8. Apparatus according to any one of claims 3 to 7 and further comprising pressing means (16) arranged to receive coated fabric from said calender for pressing said fabric.

9. Apparatus according to claim 8 comprising tension relieving means (69) between said calendar and said pressing means.

10. Apparatus according to claim 8 or claim 9 comprising a calender (18) for receiving coated fabric and applying a liner thereto.

11. Apparatus according to any preceding claim, wherein the spindles (42) are tubular, such that a bead wire can be delivered from the distal end of each of said tubular spindles in use.

13. Apparatus according to any preceding claim wherein the dispensing arm is rotatable on an axis parallel to the spindle axes.

14. Apparatus according to claim 13 wherein the dispensing arm and the spindles are rotatable in the same sense.