DE3518976A1 - Process and apparatus for detecting shading in carpets - Google Patents

Abstract

The process and the associated apparatus makes it possible to detect shading tendencies of carpets in a short-time test, in that rolling movements are executed under pressure and with a slip of the sample relative to the load according to a specific recurring sequence.

Description

Method and device for determining shading in

Carpets The invention relates to a method and an apparatus for determining shading in carpets by means of short-term tests by following a mechanical stress on carpet samples is determined by visual inspection. whether shading has occurred.

The term shading is used in connection with a carpet, when unwanted shadows become visible. That is actually more precise German expression "Florscheitelung", which says that the pile in the form of elongated Vertices and / or large island-like surfaces takes on visible contours, which significantly disrupt the appearance of the carpet. Why and when a carpet through Shading is not known. It can only be determined that in one Velor fabric, the pile thread, for example, kinks in the upper third of the knob leg, whereby the direction of rotation to the normal line position can be any It has There has been no lack of attempts by selecting the pile material or by appropriate Equipment of the carpet backing to prevent the infestation of a carpet through shading or to mitigate. Apart from general tendencies, however, it is safe to predict not possible to date for a certain carpet4 The phenomenon of shading occurs namely often only 6 - 8 weeks after the goods have been sold, whereby a direct one Connection with the strain cannot be proven.

The object of the invention is to provide a method and a device for Examination of velor carpets to find which after a short examination time and if possible even at an early stage of carpet production, for example raw carpet goods and dyed uncoated carpets, a reliable statement about whether shading infestation must be expected on the tested velor carpet.

The object is achieved according to the invention in that at least one in the direction of movement curved sole under pressure on a relative to it moved Carpet test specimen is repeatedly unrolled and that after a recovery period the process is repeated in the opposite direction of movement.

Although carpets with untrodden areas - e.g.

under cabinets - may exhibit shading, it is surprisingly succeeded by the inventive mechanical stress of a certain To achieve results over a short period of time (0.5 - 3 hours), which with reasonable certainty a statement about possibly later Allow shading infestation. The timely testing in the laboratory is of great economic efficiency Importance because of avoiding the laying of carpets, which is usually the case Shadings infestation only occurs after several weeks or months, costs and annoyance be spared from complaints.

In a special implementation of the procedure, the starting point is each time the sole unrolls again, it is offset in the unrolling direction.

This measure ensures that the carpet test specimen through putting on and unrolling the sole in different places as evenly as possible, statistically distributed stress on the pile takes place in order to provide a reliable statement about the shading tendency of the carpet test specimen.

In a further implementation of the procedure, the outside of the perimeter lying sole of the driven roller with a small radius on the outside on one Counter-rotating, freely rotating drum with a large radius attached to the carpet test specimen unrolled under each other with a maximum slip of 30%.

With different, but in the same direction, speeds a difference of advantageously 15-20% in the contact area of the sole (Roller) and carpet test specimen (drum), a slip is generated between the two parts, which obviously amplifies a possibly existing shading tendency so that already after a short-term test a reliable statement about a later shading infestation can be done.

In another implementation of the method, the slip is during of unrolling changed according to regulations.

By changing the slip while rolling, everyone can Types of stress, for example a foot when suddenly stopped, when Walking, shuffling etc. on the carpet caused, can be imitated so that this measure provides a wide range of all possible stresses stands.

In a preferred implementation of the method, the specific Pressure exerted by the sole on the carpet sample, between 1 and 30 kg / cm2, in particular between 2 - 10 kg / cm2.

By changing the specific pressure, what for example by reducing the width of the sole, it is possible to do this to adapt to the actual demands.

In one possible implementation of the method, the starting point is when the sole touches down varies locally.

By shifting the starting point - seen in the direction of rotation - it is achieved that the carpet sample is stressed as evenly as possible in the sample area will.

In one implementation of the method, a laterally reciprocating transverse movement superimposed.

By superposing this movement on the rolling movement, a rotating Movement can be generated, which is used advantageously for checking the shading behavior can be.

Two horizontal, parallel rollers arranged at the same height and spaced from one another Axles stored in a frame, one of which has an adjustable drive for both directions of rotation and the other with an adjustable braking device also for both directions of rotation, and that there is a freely rotating Drum, which can be weighed down by loads, via protruding ones attached to the end Races or on one side over the sole / carpet specimens on both rollers supports.

This device, which is simple in construction, allows all stresses, as required in the exam. With the braking device released When the roller is driven, the shoe sole rolls on the carpet sample, with both together are slightly thicker than the protruding races, now the rear one Roller by a braking device - temporarily or completely with smaller or larger Force - braked, the drum is also decelerated by the races resting there, creating a slip between the carpet sample and the sole it is still possible to sample the carpet by moving the drum parallel to its axis also to be claimed in the transverse direction.

In a particular embodiment, the ratio of the diameters is from driven roller to drum between 1: 2 to 1: 5.

The greater curvature of the sole compared to the carpet specimen corresponds the practical demands of a carpet. Next should be the circumferential length of the drum plus the integrated slip in one revolution is not an even multiple be of the circumferential length of the driven roller, so that the point of application of the Sole is constantly shifted in the circumferential direction of the drum.

In a preferred embodiment, the sole has a hardness between 30 and 40 Shore and is equipped with a surface that is medium Roughness & 0.025 µm.

Due to the given hardness, optimal results were achieved in a short time achieved, with damage to the velor carpet due to the smooth surface could be avoided.

An example of the invention is shown in the drawing and will explained in more detail below.

The figures show: FIG. 1 top view of the device; FIG. 2 front view of device Fig. 3 side view of device In Fig. 1 are arranged on two parallel belts of a frame 1 each two bearings 2, the the axes 3, 4 of the parallel spaced rollers 5, 6 with the same smaller Record diameter. The front roller 5 is on the extended axis 3 with a drive pulley 7 and carries along the wall 8 two pairs with each other so offset soles 9 that - seen in cross section - along the circumference of the roller 5 interruptions are.

The rear roller 6 is on the extended axis 4 with a brake disc 10 and is surrounded along the wall 11 with a rubber jacket. On both Rolls 5, 6, the drum 12 is supported either directly via the protruding races 13 or indirectly via the carpet test specimen attached to the wall of the drum 14 on the sole 9 on the roller 5. The drum 12 is at both ends with cylindrical journals 15, each of which carries a bearing 16 that runs smoothly.

In Fig. 2 the device is shown in side view. Next to the elements already mentioned here are the motor 17 with drive pulley 7, belt 18 and drive pulley 19 can be seen. Furthermore, the weights 20 can be seen, which load the drum 12 via the bearings or journals 15.

In Fig. 3 the device is shown in side view. the Braking device consists of brake disk 10, brake band 21 and weight 22.

Example: rollers 120 1 = 1000 mm drum 260 1 = 840 mm dead weight 63 kg + additional weight 2x10 kg shoe soles natural rubber 120 d = 8 mm hardness 32 Shore Surface (film) roughness 0.022 gm Carpet sample 840 x 740 mm air-conditioned at 30 rel. Humidity 20 "C 48 hours. The carpet sample is placed on the drum by means of attached with double-sided tape. At a speed of 651 / min-l and a slip from 15 to 20% the carpet sample is subjected to the following cycle of 15 sec counterclockwise rotation 20 sec dwell time 15 sec clockwise rotation 20 sec dwell time over a test period of 30, 60 or 90 minutes. This is followed by a visual inspection and classification into one of the 6 classes (1 = no shading, 6 = pronounced shading).

Claims (9)

Claims 1) Method for determining shading in carpets by short-term tests by after a mechanical load of carpet samples is determined by visual inspection; whether shading has occurred, characterized in that that at least one curved sole in the direction of movement under pressure on a relative to this moving carpet test specimen is repeatedly unrolled and that after a recovery period the process is repeated in the opposite direction of movement. 2) Method according to claim 1, characterized in that the starting point is offset in the unrolling direction each time the sole rolls off again. 3) Process according to claims 1 and 2, characterized in that the sole of a driven roller with a small radius lying on the outside of the circumference on the outside on a freely rotating drum with a large radius attached carpet test specimen with a slip of a maximum of 30% unrolled among each other will. 4) Method according to claims 1-3, characterized in that the The slip is changed during unwinding according to the regulations. 5) Method according to claims 1-4, characterized in that the specific pressure exerted by the sole on the carpet specimen between 1 and 30 kg 1cm2 can be changed. 6) Process according to claims 1-5, characterized in that during a laterally to and fro transverse movement is superimposed on unwinding, 7) Device for carrying out the method according to claims 1 to 6, characterized in that that two horizontal, parallel, at the same height and at a distance from one another arranged rollers (5, 6) are mounted in a frame (1) via axles (3, 4), one of which has an adjustable drive (7, 17, 18, 19) for both directions of rotation and the other with an adjustable braking device (10, 21, 22) also for both directions of rotation are connected, and that there is a freely rotating drum (12), which can be weighed down by loads (20) via protruding ones attached to the end Races (13) or on one side over the soles (9) / carpet test item (14) both rollers (5, 6) supported, 8) Device according to claim 7, characterized in that that the ratio of the diameter of the driven roller (5, 6) to the drum (12) is between 1: 2 to 1: 5. 9) Device according to claim 7-8, characterized in that the Sole (9) has a hardness between 30 and 40 Shore and is equipped with a surface which has a mean roughness <= 0.025 to.