Document 2NbaM6ZeBzk2zKe5zaE3X19N

PLAINTIFF'S LAllLbll PATENT SPECIFICATION Application Date: May 24, 1946. Complete Specification Left: March 11, 1947. Complete Specification Accepted: Feb. 1, 1949. 'L 617,103 15826/46. Index at acceptance:--Class 140, E2a8, G. PROVISIONAL SPECIFICATION Improvements in the Manufacture of Fibrous Materials We, British Belting & Asbestos Limited, a British Company, of Scandin avia Mills, Cleckheaton, in the County of York, and Raymond Drake, a.m.i.mech.e., of Grangefield, Westgale Hill, Bradford, in the County of York, of British Nationality, do hereby declare the nature of this inven tion to be as follows : -- This invention relates to the manufacture 10 of fibrous materials, and is particularly concerned with the production of a coherent fibrous web or fleece. According to the invention, textile fibres are formed into a coherent web or fleece, 15 treated with a bonding agent, and consoli dated into a felted film or billet capable of being moulded. The fibres are preferably teased or carded into the form of the coherent fleece since 20 the nature of the teasing or carding opera tion separates and opens out bunches of fibres and makes possible the production of a fleece of substantially regular density and thickness. The fleece may be impregnated 25 with a liquid bonding agent, or the bonding agent may be applied to the fleece in solid, comminuted or powder form. If desired, the fleece may be treated with both forms of bonding agent, the comminuted form 30 preferably being applied to the fleece before impregnation with the liquid form. When the fleece is treated with the liquid bonding agent, such agent may be sprayed along the length of the fleece, or the fleece may 35 be immersed in a bath of the liquid. Consolidation of the treated fleece may be effected by blocking or pressing lengths of the fleece, or the fleece? may be conducted through the pip of one or more co-operating 40 pairs of squeeze rollers. The blocking, pressing or nipping surfaces may be heated in order to induce suitable reaction in respect of substances contained in the fleece, e.g. when a thermoplastic, com 45 minuted bonding agent is employed which requires the application of heat to become adhesive. Fibrous materials such as asbestos, cotton, wool, silk, artificial silk, fibrous 50 glass, flax, hemp, jute, sisal and like bast fibres, separately or in combination, may IPrice 2/-] '<" - A; - - yf; : y: v - be treated according to the invention. Threads, strips or wires of materials adapted to modify the characteristics of the fleece, or to reinforce the fleece, may be 55 introduced into the structure of the fleece either before or after the treatment of the fleece with the bonding agent. The invention is particularly applicable to the treatment of asbestos fibres in the 60 manufacture of films, webs, wads or like structures convertible by a moulding or pressing operation into strips, sheets or blocks having substantial mechanical strength and resistance to abrasion. For 65 example, the process may be applied in the manufacture of friction elements to be employed as friction pads, clutch facings, brake linings, brake blocks, and like pro ducts which in use are subjected to sub 70 stantial abrasion and mechanical stresses. According to one method of carrying out the invention, asbestos fibres are carded and formed into a coherent web or fleece which is conducted continuously through 75 an impregnating bath of liquid phenolic resin. The resin-impregnated fleece is taken from the.bath and passed through' the nip of a co-operating pair of squeeze rollers arranged to consolidate the fleece into a 80 felted film or billet. Such film or billet is cut into convenient lengths which are dried and subsequently moulded under the com bined influences of heat and pressure into shapes appropriate for use as friction- 85 elements, e.g. of the types referred to above. Conveniently, the fleece of asbestos fibres delivered from the card is carried on a gauze conveyor adapted to conduct the 90 fleece into and out of a bath of liquid phenolic resin. The fleece is preferably held in contact with th? conveyor during the dipping or impregnating process by any suitable means, e.g. a roller, paddle or 95 second gauze conveyor co-operating with the first. The amount of liquid resin absorbed by the fleece may be controlled by a nip roller bearing against the fleece as it emerges from the bath, and arranged, in a 100 manner such that excess liquid is sqtfeezed out of the fleece. The pressure applied to Jid)t ff CTD026062 4 617,103 in the apparatus illustrated in Fig. 1; and Fig. 5 is a section, 'on an enlarged scale, on tile line 5-5, Fig. 4. In the following description with refer- 5 cnee to the accompanying diagrammatic drawings, the invention is described more particularly in its application to the produc tion of friction elements. Referring to Fig. 1, fibrous asbestos is 10 fed from the supply hopper 6 to weighing mechanism 7 which deposits measured quantities of fibre 8 on the lattice 9 where the fibre is spread into a layer by the rockerbar 10. The lattice 9 travels in the direc- 15 tion shown by the associated arrow and delivers the layer of fibre 8 to a pair of nip rollers 11 which feed the layer to the sur face of the rotating toothed cylinder 12. The cylinder 12 and co-operating toothed 20 rollers 13, 14 tease and comb the fibres 8 into a continuous thin substantially homo geneous fleece 15 which is stripped from the rollers 14 by doffing-combs 16 and delivered by lattices 17 to a lattice 18. 25 The lattice 18 is progressively lengthened and shortened by reciprocation of the roller 19 towards and away from the roller 20 in a manner such that the fleece 15 is deposited in superposed layers 21 on the cross-lattice 30 22 (see also Fig. 4). The cross-lattice 22 travels in a direction transverse to that of the lattice 18 and carries the superposed layers 21 of the fleece to the nip of a co operating pair of vertical lattices 23 (Figs. 35 1 and 4) which together press the layers 21 into a continuous web 24 of increased thick ness. The width of the web 24 is controlled by the extent of the reciprocation of the roller 19, while the thickness of the web 40 depends on the number of layers of which it consists. Such number is a function of the rate of travel of the lattice 22 relatively to the rate at which the fleece 15 is deposited thereon. 45 From the co-operating vertical lattices 23 the continuous web 24 is conducted by a guiding surface 25, formed as a side of a tank 26 to the nip of a co-operating pair of wire mesh lattices 27, 28 which travel at the 50 same surface speed as the lattices 23. Such lattices are caused by their guide rollers 29 to conduct the web 24 beneath the level of a liquid bonding agent such as liquid phenol-formaldehyde resin 30 contained in 55 the tank 26, the open structure of the wire mesh permitting the liquid freely to reach the fibres comprising the web. The web 24 is thus saturated with the liquid and con ducted to the nip of a pair of rollers 31, 32 60 which rotate at a surface speed equal to that of the lattices 27, 28. The rollers 31, 32 consolidate the web 24 into a continuous coherent web or billet 33, and squeeze excess liquid therefrom. The excess liquid 65 is collected in a trough 34 from which it is conducted back to the tank 26 by a drain pipe 35. Alternatively-, the consolidation of the web or billet 33 may tie effected by block ing or pressing lengths thereof between 70 suitable pressure members. Tlie quantity of liquid bonding agent applied to the web 24 may be varied in accordance witli the ultimate use of the product. Thus, asbestos (Hires, or asbestos 75 fibres blended with cotton or rayon staple fibres, treated according to the invention and intended for conversion into friction elements may have applied thereto liquid phenol-formaldehyde resin in quantities 80 such as will give from 20% to 30% or even 40% of resin by weight in the consolidated web 33 when in the dry state. The degree of pressure applied to the impregnated web 24 by the nip rollers 31, 85 32, can be varied by adjusting screws 44 which bear on blocks 4 freely mounted on the shaft 5 of the upper roller 31 (see Fig. 5). As will be apparent, the quantity of liquid remaining in the web 24 varies sub- 90 stantially inversely as the pressure to which the web is subjected. The lower roller 32 is flanged to receive the upper roller 31, the flange supporting the edge of the web 24 during its consolidation into the billet 33. 95 One or both of the pressure rollers or other pressure-applying members may be heated for the purpose of inducing suitable reaction in the bonding agent. A conveyor belt 36 supported and driven 100 by rollers 37.at the same surface speed as the rollers 31, 32 carries the continuous billet 33 to a guillotine, the blade 38 of which is caused to descend against a pad 39 by a rotating cam 40, and cut the billet 105 into predetermined lengths 41. The cut lengths 41 fall on a conveyor belt 42 sup ported and driven by rollers 43, and are collected from such belt for drying and subsequently moulding under the combined 110 influences of heat and pressure, e.g. into shapes appropriate for use as friction elements. If desired, fibres of materials other than asbestos may be blended with the asbestos 115 fibres fed from the supply hopper 6. Thus, cotton or rayon staple fibres may be blended with the asbestos fibres within the hopper, or such fibres may be formed into a scutcher lap 45 (Fig. 1) and fed in predetermined 120 amount by nip rollers 46 to the nip rollers 11 for presentation with the layer 8 of asbestos fibre to the toothed cylinder 12. Where short-fibre asbestos is employed, an admixture of cotton or rayon staple fibre of 125 from 5% to 30% by weight of the asbestos fibres may be effected. Powders or substances in comminuted form, e.g. a powdered bonding agent, may be added to the fleece 15 from a supply 130 CTD026065 617,103 liopper 47 (Figs. 1, 2 and 3). The hopper contact with the mesh 61 in a manner such comprises a trough 48 carrying in its base that the mesh becomes an integral part of a rotatable roller 49, the surface of which the billet 33 which is cut into lengths 41 by is formed with longitudinal grooves 50. the blade 38 in the manner described above.' 5 The roller 49 is mounted on a shaft 51 It will be understood that the invention 70 which is rotated by a pulley 52 driven by a is not limited to the particular embodiment chain 53. Powder 64 placed in the trough hereinbefore described. For example, the 48 lodges in the grooves 50 of the roller 49. apparatus for carrying out the various Stationary pads 54 fitting closely against steps involved in the process may be modi 10 the face of the roller 49 prevent the powder fied in various ways. Furthermore, it will 75 falling freely from the trough. be understood that the process and appara Rotation of the roller 49 causes the tus hereinbefote described with reference powder lodging in the grooves 50 to scatter to the accompanying diagrammatic draw beneath the trough. The supply hopper 47 ings is generally applicable for the produc 15 is mounted across the width of the carding tion of a coherent web or billet from various 80 machine in a manner such that the powder fibrous materials or combination thereof 64 is caused to scatter over the fleece 15 with or without the introduction of fillers, shortly after such fleece leaves the rollers such web or billet being capable of being 14. At this stage the fibres comprising the moulded or pressed to produce strips, sheets 20 fleece are in open form and permit the or blocks of any suitable shape having sub- 85 grains of powder to enter intimately into stantial mechanical strength and applicable the structure of the fleece. The amount of ' for various purposes according to the nature powder applied to the fleece may be in of the fibres utilised and the substances creased or decreased by increasing or incorporated therewith. 25 decreasing the rate of rotation of the roller Having now particularly described and 90 49. The depositing of the fleece 15 in ascertained the nature of our said invention superposed layers 21 on the cross-lattice 22 and in what manner the same is to be per assists in blending the powder 64 with the formed, we declare that what we claim is : -- component fibres of the fleece. 1. A process for producing fibrous 30 The powder 64 may comprise a single materials of the kind referred to, com- 95 substance or a blend of two or more sub prising forming fibrous material into a con stances adapted to vary the character or tinuous fleece which is, in a manner known colour of the fleece 15. When the product per se, cross-folded to form a multi-layer according to the invention is intended for continuous web, impregnating said multi 35 use as a friction element, friction-modifying layer web with a liquid hardenable bonding 100 or enhancing materials may be added to the medium, such as an artificial resin, and fleece. For example, particles of metal, thereafter consolidating the impregnated rubber, iron oxide, rottenstone, wood-flour web by the application of pressure. or like substances may be scattered on the 2. A process according to Claim 1, 40 fleece 15 from the hopper 47. In the manu wherein the application of pressure to the 105 facture of brake lining or clutch facing multi-layer web for the purpose of con materials fibrous glass or powdered or com solidation also serves to expel excess liquid minuted brass or zinc may, with advantage, bonding medium. be added to' the fleece. 3. A process according to Claim 2, 45 Friction materials according to the in wherein the consolidating pressure is 110 vention may be reinforced for heavy-duty adjusted so that the percentage of bonding applications by the introduction into the medium retained in the multi-layer web web 24 of threads or strips of materials such after consolidation and in the dry state is, as steel threads or wires. Similarly, metallic between 20% and 40% lay weight of the 50 fabric or woven steel, brass, zinc or alumin bonding medium. 115 ium wire mesh may be introduced as a 4. A process according to any of the pre backing or reinforcing means. ceding claims, wherein the consolidated A method of incorporating a mesh back multi-layer web is cut into lengths to form ing into the web 24 is illustrated in Figs. 4 suitable blanks for subsequent moulding 55 and 5, in which a roll 60 of woven steel operations with the application of heat and 120 mesh 61 of width equal to that of the web pressure to produce substantially rigid 24 is1 mounted on a shaft 62 rotatably sup elements. ported in open bearings 63. The mesh 61 5. A process according to any of the pre is led from the roll 60 to the nip of the ceding claims, for the production of friction 60 rollers 31, 32, where the mesh is gripped elements, wherein the fibrous material con- 125 and caused to unwind from its roll at the sists of asbestos. peripheral speed of the rollers. The pres 6. A process according to Claim 5, sure between the rollers 31, 32 while con wherein additional fibrous material, such as solidating the web 24 into the continuous cotton or rayon, is combined with the 65 billet 33, squeezes the web intimately into asbestos fibres. '" CT&026066 617,103 7. A process according lo Claim 6, wherein the cotton or rayon staple fibres are added in the proportion of 5% to 30% by weight of the asbestos fibres. 5 8. A process according to Claim 6 or Claim 7, wherein the admixture of cotton or rayon fibres with the asbestos fibres takes place before the fleece-forming operation. 9. A process according to any of the pre10 ceding claims, wherein fillers, such as friction-modifying materials in powdered or comminuted form, are introduced into the fleece prior to the folding operation. 10. A process according to Claim 9, 15 wherein the fillers comprise fibrous glass, zinc or brass. 11. A process according to any of the preceding claims, wherein, for the purpose of mechanical reinforcement, metallic 20 elements in the form of threads, strips, wires or mesh are embedded in the impreg nated multi-layer web in the course of con solidating the same. 12. A process of producing friction 25 elements which comprises subjecting asbes tos fibres, with or without additional fibres, to treatment for the production of a fleece in the form of a continuous layer, applying to said layer solid friction-modifying 30 materials in powdered or comminuted form, cross-folding the treated fleece upon itself in a manner known per se to form a con tinuous multi-layer web, impregnating the said web with a liquid phenol-formaldehyde 35 resin or like bonding medium, subjecting the impregnated web to a consolidating pressure to expel surplus liquid and to produce a coherent web or billet, cutting the web or billet into suitable lengths, and 40 from such lengths producing such friction elements by a moulding or pressing opera tion involving the application' of heat and pressure. 13. Apparatus for carrying out the pro45 cess . hereinbefore specified, comprising means for forming fibres into a continuous fleece, means for conveying said fleece to folding apparatus whereby it is cross-folded upon itself on a transverselj7 disposed lattice or the like for the production of a multilayer web, means for conveying said multi layer web through a bath of liquid bonding medium, and means, such as nip rollers, for consolidating the impregnated web. 14. Apparatus according to Claim 13,, wherein means are provided for adjusting the pressure applied by the said nip rollers, for the purpose described. 15. Apparatus according to Claim 13 or Claim 14, comprising means for introducing on to the fleece, prior to the folding operation, solid substances in powdered or comminuted form. 16. Apparatus according to Claim 15, wherein the means for introducing the solid substances comprises a hopper, a grooved roller forming the base of the hopper, and means for rotating the grooved roller. 17. Fibrous material convertible by a moulding or pressing operation into strips, sheets or blocks having substantial mech anical strength, produced by the process claimed in any of the preceding Claims 1 to 13. 18. Strips, sheets or blocks having sub stantial mechanical strength, produced by the process claimed in Claim 4. 19. Friction elements, produced by the process claimed in Claim 12. '20. The improved process for the manu facture of fibrous material convertible by a moulding or pressing operation into strips, sheets or blocks having substantial mech anical strength, substantially as described with referenceto the accompanying diagrammatic drawings. 21. Apparatus for carrying out the pro cess herein claimed, substantially as des cribed with reference to the accompanying diagrammatic drawings. Dated this 11th day of March, 1947. URQUHART-DYKES & LORD, Chartered Patent Agents, Maxwell House, 11 Arundel Street, Strand, London, W.C.2, and 12 South Parade, Leeds 1, Yorks. 50 55 60 65 70 75 -80; 85 90 Printed for His Majesty's Stationery Office by Charles Birchall & Sons, Ltd., Liverpool.--1949. Code 39-219. Published at the Patent Office, 25, Southampton Buildings, London, W.C. 2., from which copies, price 2s. Od. each (inland! 2s. Id. (abroad) may be obtained. /}' /trr CTD026067 617,103 COMPLETE SPECIFICATION /SHEET [T h is D ra w in g ia a re p ro d u c tio n o f th e O r ig in a l on. CTD026068