Background to the Invention Pile carpets of all methods of manufacture comprise a relatively soft and flexible pile projecting above and from a backing material. Commonly the pile is composed of a textile yarn, which may consist of one or more plies, and which is threaded through the backing material or may be adhered to the backing material. The pile may be composed of natural and/or synthetic fibres, or be a blend of two or more fibre types. The pile yarn may be cut into short lengths which are presented in the carpet as tufts with the cut ends forming the upper surface of the carpet, or the pile yarns may remain as uncut loops protruding above the carpet backing, or the carpet may consist of a combination of cut and loop pile tufts.

Whatever the carpet construction, the pile projects generally in a direction perpendicular to the plane of the backing, but is sufficiently flexible that individual, or groups of, tufts can be deformed and caused to lean away from the perpendicular when subjected to a compressive load such as a footfall.

Generally the direction of lean is determined by the manufacturing process and the direction of the consequent horizontal shear forces. The carpet pile has elastic properties and will recover most of its perpendicular orientation after removal of the deforming force. In practice the pile is not perfectly elastic and individual, or groups of, tufts may retain a lean which is stabilised by friction between adjacent pile tufts or between fibres within a single tuft. At the next footfall the lean of a tuft or group of tufts may be reinforced in the same direction or may be reversed or displaced in a different direction, depending on the individual circumstances of so random an event. However, should the majority of a sequence of footfalls act to lean a group of tufts in the same direction then the tuft lean can become permanent. In practice it often occurs that adjacent groups of tufts in a carpet are caused to lean permanently in opposite or widely differing directions, with the consequence that the two areas appear to have quite different shades of colour when seen under certain conditions of illumination such as oblique lighting from one direction only.

This phenomenon is generally regarded as an unsightly carpet fault and is frequently referred to as"shading"by virtue of its appearance. Similarly, since the darker shade areas generally have the appearance of being wet the phenomenon is also frequently referred to as"water marking". The phenomenon of shading is also characterised by the further phenomenon that the dark and light areas interchange when the conditions of viewing are reversed.

Shading can occur in any carpet installation on any floor site, but in certain sites its development and the direction of pile lean is quite predictable from the general direction of flow of foot traffic and the resultant forces imposed on the pile tufts. Typical predictable sites are along corridors and at points of turning such as corridor corners and doorways. Shading in such areas is generally accepted as an inevitable part of carpet wear and not necessarily a cause for complaint. However, it sometimes happens that severe shading develops in area installations where there is no particular or specific direction of foot traffic. The shading may appear to be totally random in location and in the size of the shaded area, or sometimes there may be shading preferentially adjacent to joints between carpet strips or periodically across a carpet strip. Such shading, random or otherwise, is generally considered an unacceptable carpet fault and is frequently the subject of complant, resulting in expensive settlements.

The phenomenon of shading can be observed in both cut-pile and loop-pile carpets, although it is far more visible in cut-pile carpets and not usually, associated with loop-pile carpets.

Studies of the phenomenon of shading and its development have revealed the mechanisms involved both at the intra-tuft level and the inter-tuft level.

Understanding these mechanisms has now led to the development of carpet treatments and apparatus to apply these treatments, which substantially reduce the propensity for a carpet to shade in any use site.

Understanding that the phenomenon of shading can occur very quickly (within a few days or weeks) after installation of the carpet, and that the shaded patterns soon become permanent and irreversible, then an anti- shading treatment may rely upon imparting a definite unidirectional lean, uniformly to all the tufts in the carpet and stabilising that lean before the carpet is installed. In effect the carpet is subjected to any treatment which produces that pile condition whence shading can be seen but with all of the pile leaning in one direction only.

It is an object of the present invention to so treat and condition a carpet to produce in the pile that state of pile lean normally manifested by the appearance of shading but with all the pile leaning substantially in one direction.

It is a further object of the invention to provide a method and apparatus of producing in a controlled manner uniform and unidirectional pile lean and to stabilise the pile lean with that orientation and to restrict reversal of the pile lean during actual use on the floor.

It is also an object of the present invention to lock-in a preferred pile an by pretreating the carpet at a high pressure to invoke frictional restraints normally only induced by long periods of wear by foot traffic.

Summarv of the Invention According to a first aspect of the invention there is provided a method of laying the pile of a carpet uniformly in one direction and stabilising the pile in its leaning orientation, the method including the steps of: providing a multiplicity of compression means to lay a pile in a preferred direction in a number of compression and relaxation cycles; treating a carpet with a multiplicity of compression/relaxation cycles to induce a preferred lean to the pile; and consolidating the pile orientation and state by inducing intra-tuft fibre migration and inter-tuft entanglements similar to those observed in a naturally and severely shaded carpet. According to a second aspect of the invention there is provided means for laying and compressing a pile in a preferred orientation, and means for relaxing the pile between compression cycles, the means including a multiplicity of driven compression rollers interspersed with idling rollers spaced and sited so as to produce a multiplicity of compression/relaxation cycles.

According to a third aspect of the invention there is provided an alternative method of laying the pile in a preferred direction and stabilising the pile in its leaning orientation, the method including the steps of: providing a method of laying the pile in a preferred direction, providing a method of temporarily holding the pile in the layed orientation for a period of time; providing a method of setting the pile in the layed orientation; and treating the carpet to lay the pile in the preferred orientation by a controlled leaning and setting of the pile with the preferred layed orientation by steaming.

According to a fourth aspect of the invention there is provided apparatus for laying a pile in a preferred orientation, means for temporarily holding the pile in the preferred orientation, and heating means for thermally annealing the fibres whilst held in the preferred orientation, the means including driven rollers to transport the pile against a surface to be brushed and to produce a pile lean and to temporarily hold the pile in a preferred layed orientation; and a heated chamber in which the pile fibres are annealed. There are a number of ways of laying the pile in the preferred orientation and consolidating the pile with that orientation which fulfil the conditions of the invention.

According to a fifth aspect of the invention, there is a pile carpet which has undergone an aforementioned process to lay the pile in a uniform direction and stabilise the lay of the pile so that it is resistant to reversal in use thereby reducing its propensity to shade or watermark in an objectionable manner.

Further aspects of the invention will become apparent from the following description which is given by way of example only.

Brief Description of the Drawings The present invention will now be described by way of example only with reference to the attached drawing in which: Figure 1: depicts diagrammatically, in cross-section, a series of rollers arranged and designed to subject a carpet to a multiplicity of compression and relaxation cycles.

Figure 2: depicts diagrammatically, in cross-section, means according to the invention for brushing the pile into a preferred layed orientation, a surface positioned to retain the pile in its preferred orientation, rollers to transport the carpet through the means and a surrounding heated chamber.

Description of the Preferred Examples Referring now to Figure 1 a pile carpet 1 is transported through a sequence of driven compression rollers 2 and 3 which are loaded to a pressure of at least 200 kg per metre of roller length to cause the pile to lean in the trailing direction whilst subjecting the pile to a compression/relaxation cycle. An idling rollers 4 can be included to provide a curved path for the carpet which opens the pile to assist the relaxation part of the cycle. The number of groups of rollers 2,3 and 4 can be increased to provide sufficient compression/relaxation cycles to achieve a desired pile orientation and degree of stability.

During the compression phase of the cycle pile tufts are caused to lean over at an acute angle to the carpet backing to an extent that will stress individual fibres within a tuft and produce a small amount of inter-fibre movement. During the relaxation phase the stress is removed from the fibres, but by virtue of inter-fibre frictional forces, the fibre movements induced in compression are not necessarily fully reversed. In practice relaxation can result in further inter-fibre displacements as fibres move towards stable positions under conditions of minimum energy. Repeated compression/relaxation cycles result in gradually increasing pile lean stabilised by fibre migrations. Further stability of pile orientation is derived from fibre ends protruding from the tufts becoming interentangled with adjacent tufts by virtue of a small degree of felting resulting from the compression/relaxation cycles. The process of pile laying and stabilisation is thus closely similar to the effect produced by ordinary but directional walking on a carpet in which the direction of pile lay is consistent in specific areas, and quickly becomes permanent and irreversible. The objectionable problem of shading arises when the pile lay differs between adjacent areas in the carpet. According to the present invention the stabilised pile lay imparted to the carpet during the finishing process will be further consolidated in use and will be highly resistant to pile reversal in areas of random walking direction.

Referring now to Figure 2, a pile carpet 1 is transported by driven rollers 2 between two smooth surfaces 5 and 6 positioned in a fixed spaced relationship on opposite sides of the carpet such that the upper surface 6 brushes against the carpet pile causing it to be held in a leaning orientation during the traverse of the carpet across the space between surfaces 5 and 6. In order to increase the dwell time during which the pile is confined in the preferred orientation the carpet can be reversed by passing around roller 7 and over the top of the smooth surface 6 and under further driven rollers 8 which assist transportation. The whole system can be housed within a chamber 9 which is supplied with a preferred fibre annealing agent such as steam. It is obvious that the annealing process can be further prolonged as necessary by increasing the path length between surfaces 5 and 6 or by duplicating the systems for example in a vertical stack. This method has the advantage that the pile can be laid in a preferred direction by brushing against a surface under low pressure, and stabilised in its preferred orientation by annealing.

It is to be understood that the pile can be layed in a preferred direction and the pile lay consolidated by various other means consistent with the spirit of the present invention. For example the pile can be layed by means of rollers and held in its layed orientation by rolling the carpet under tension into a roll.

Pile laying is preferably done immediately prior to the rolling point and can be consolidated by setting in an autoclave or by an extended period of storage in an appropriate atmosphere.

Industrial Applicabilitv Thus by this invention there is provided a method and apparatus for laying the pile of a carpet with a preferred orientation and stabilising the pile in that preferred orientation, making the carpet resistant to pile reversal in use and reducing the propensity of the carpet to shade in an objectionable manner.