SPORTS FLOOR WITH LINE MARKING

Abstract: The invention relates to a sports floor with line marking. The invention has for its object to provide a sports floor with line marking which is very simple and inexpensive, can be laid simply and offers a virtually unlimited flexibility with regard to the line marking patterns to be formed, whereby is achieved that the line marking can be adapted in a short time, whereby the sports floor is made suitable for a different sport. In order to bring about the said objects the invention provides a sports floor (1) displaying the feature that the line marking comprises a layer (15) with liquid crystals which can be activated by energizing means and the optical properties of which change on activation.

Description: SPORTS FLOOR WITH LINE MARKING The invention relates to a sports floor with line mark¬ ing. Such a sports floor is known. It is for example known to use (invisible) line marking in sports halls which is illumi- nated by ultraviolet radiation falling thereon. Through selec¬ tion of the spectrum, for instance the dominating wavelengths of the striking light, the colour of the line marking can be chosen as required. The drawback of this known system is that the paint involved is toxic and expensive, which makes its use problematic. Efforts have also been made to lay patterns of fluores¬ cent tubes in sports floors. This system has also been found in practice to encounter problems too great for it to be applied on any scale. With an eye to this known art the invention now has for its object to provide substantially a sports floor with line marking which is very simple and inexpensive, can be laid simply and offers a virtually unlimited flexibility with regard to the line marking patterns to be formed, whereby is achieved that the line marking can be adapted in a short time, whereby the sports floor is made suitable for a dif¬ ferent sport. In order to bring about the said objectives the invention provides a sports floor displaying the feature that the line marking comprises a layer with liquid crystals which can be activated by energizing means and the optical properties of which change on activation. A simple control is obtained with an embodiment wherein the energizing means are of the electrical type. In a particular embodiment the sports floor displays the feature that the activation is of the electrical type. The liquid crystals can in this case change state through the application of an electrical field. According to the invention preference is however given to an embodiment wherein the activation is of the thermal type. Use can be made here in particular of a pattern of electrical heating elements above which the layer for activation is situated. Through supply of current an increase in temperature is obtained in the heating elements which causes the layer for activation to change state such that the line marking pattern becomes vis¬ ible. It will be apparent that the layer for activation must be suitable for such an energizing. The temperature increase can for instance lie in the order of several tens of degrees. Such a limited temperature increase can never cause incon¬ venience to anyone practising sport on the sports floor in bare feet. In a specific embodiment the floor has the feature that the layer for activation is opaque in the rest state and has a colour that is substantially the same as the colour of the floor, and in activated state is transparent, and that situ¬ ated under the layer for activation is a colour layer whereof the colour contrasts with the colour of the floor. The sports floor, or at least the top layer thereof, will generally be of wood and will for instance take the form of a parquet floor. A sports floor provided with line marking will generally be finished with a transparent, hard top coat. The above mentioned variant is preferably embodied such that the colour layer has a considerable thermal conduction relative to the material of the sports floor and that the heating elements are embedded in the colour layer. This colour layer can for instance consist substantially of polyester. It is remarked that it is known to embody line markings painted on the ground in different colours for different sports. That this can cause confusion will be evident. The system according to the invention does not require such a variety of colours; use can simply be made of one colour which gives the best possible contrast with the upper surface of the wooden top layer. In particular the line marking can be black. A very practical embodiment is that wherein the layer for activation is incorporated in a corresponding pattern of grooves in the floor. When heating elements are used they are arranged thereunder in the relevant grooves. In a particular embodiment the floor displays the charac¬ teristic that the layer for activation consists of a cured slurry. This slurry is commercially available in diverse compositions and contains the liquid crystals. The sports floor preferably has the feature that the floor, at least in the region of the line marking, is covered by a transparent or opal top coat. In the case of a sports floor with line marking that is suitable for different sports, wherein selective energizing of the systems serving for the different sports has to be possible, intersecting of lines for energizing and lines not to be energized will often occur. According to the invention a variant is applied to this end wherein the line marking displays locally an intersecting of two lines, at the position of which the layer for activation is interrupted in both lines at both sides. During the production stage the layer for activation can readily be cut through or removed over a short length from the relevant lines. As a result no "seepage" of the thermal effects can occur, whereby the lines preserve their sharply defined character. The invention also provides a method for providing a sports floor with line marking, comprising the steps of: (1) providing a sports floor, for instance of wood; (2) arranging a pattern of grooves, for example by cutting, corresponding to the desired line marking; (3) laying heating elements, for instance wires, in these grooves; (4) covering these heating elements with the colour layer, for instance a liquid, curable polyester; (5) arranging thereover the layer for activation, for example a curable slurry; and (6) coupling connecting means to the heating elements for connection to energizing means. The sports floor will generally take a form such that the line marking pattern is sub-divided into segments which are coupled by means of electrical connections to a central energizing device which can for instance be controlled from a microprocessor or PC system. Via the electrically conducting connections the activation of the relevant line marking seg¬ ments takes place by means of such a selective energizing. The invention will now be elucidated with reference to the annexed drawing, in which: Fig. 1 shows a sports floor according to the invention; fig. 2 shows II-II from fig. 1 partly in broken away perspective view and partly in cross section; fig. 3 is a detail of a cutting device for cutting a groove; fig. 4 is a cross section through a line according to the invention; fig. 5 shows a partly broken away perspective view of a portion of a sports floor at the location of the crossing of two lines. Fig. 1 shows a sports floor 1 according to the invention. This comprises a pattern of lines that is suitable for basket¬ ball and volleyball. Shown with full lines is the line marking 2 for basketball, while the line marking for volleyball is shown with broken lines 3. Controlling takes place from a central control unit 4 which is coupled to the line markings 2 , 3 by means of cables 5. By means of appropriate operation of the central control unit 4 either the basketball line marking 2 or the volleyball line marking 3 can be made visible at choice. Fig. 2 shows the construction of the line marking accord¬ ing to the invention. Placed onto a concrete floor 6 is a top layer 7 of wood. Grooves 8 are cut into this top layer, for instance by a cutting operation to be described below. In the bottom of these grooves 8 are laid conductor wires 9 which serve for through-feed of current for heating. The groove 8 is filled with a mass 10 consisting of black poly¬ ester. The smooth upper surface 11 thereof lies in the same plane as the smooth upper surface 12 of the wooden top layer 7. The colour of the black polyester contrasts with the light colour of the wood of the top layer 7. Arranged on either side of the surface 11 with a slight clearance are two bound¬ ing layers 13, 14. Arranged between the bounding layers 13, 14 is an layer for activation 15. This is applied as slurry, therefore in more or less liquid state, and then cured. Sub¬ sequently applied thereover is a double top coat 16, 17 con¬ sisting respectively of isocyanate and a very hard and wear- resistant material that is translucent and therefore trans¬ parent or opal. Without thermal activation the layer for activation 15 is opaque and has substantially the same colour as the upper surface 12. The two surfaces do not thereby contrast with one another and the line marking is invisible. When as a result of current supply through the wire 9, through heat conduction through the mass 10 of the polyester the layer for activation 15 is heated to a sufficient extent it becomes transparent and the black surface 11 thereby becomes visible through the layer for activation 15 and the top coats 16, 17, whereby the line marking becomes visible. It is noted that the bounding strips 13, 14 serve exclu¬ sively for the once-only arranging of the layer for activation 15 at the correct width and are subsequently removed. They are however drawn in for the sake of completeness in the clarity in the figure. Fig. 3 shows a cylindrical cutter 18 which is carried rotatably by a frame 19 and can be driven by an electromotor 20. The cutter is driven rotatably in the direction of an arrow 21 and moved in the transporting direction designated with the arrow 22. Due to its form the cutter 18 can arrange a groove 23 in the top layer 7. Fig. 4 shows three identical, mutually adjoining grooves 23 in the recessed central portion whereof are laid the wires 9. The grooves 23 are further filled with the polyester mass 10. Placed thereon is the layer for activation 15 and the whole is subsequently covered with a top coat 25. The width of the layer for activation 15 is selected relative to the width of the grooves 23 such that the whole of it can be heated thereby to a sufficient extent. Fig. 5 shows a crossing between two lines 26 and 27. The wires 9 of both lines are isolated from each other. The groo- ves intersect but, as the figure clearly shows, the layer for activations 15 are completely separated from each other at the four sides of the relevant intersection, whereby an only negligible thermal influence is possible from the one activa¬ ted line to the other. A sharp division of both lines is hereby always ensured. The wires 9 have to be able to provide the layer for activation with a sufficiently large temperature increase when current is fed through. Copper wire for instance is highly suitable. *****

Claims: CLAIMS 1. Sports floor with line marking, characterized in that the line marking comprises a layer with liquid crystals which can be activated by energizing means and the optical proper¬ ties of which change on activation. 2. Sports floor as claimed in claim 1, characterized in that the energizing means are of the electrical type. 3. Sports floor as claimed in claim 2, characterized in that the activation is of the electrical type. 4. Sports floor as claimed in claim 2, characterized in that the activation is of the thermal type. 5. Sports floor as claimed in claim 4, characterized by a pattern of electrical heating elements above which the layer for activation is situated. 6. Sports floor as claimed in claim 5, characterized in that the layer for activation is opaque in the rest state and has a colour that is substantially the same as the colour of the floor, and in activated state is transparent, and that situated under the layer for activation is a colour layer whereof the colour contrasts with the colour of the floor. 7. Sports floor as claimed in claim 6, characterized in that the colour layer has a considerable thermal conduction relative to the material of the sports floor and that the heating elements are embedded in the colour layer. 8. Sports floor as claimed in claim 7, characterized in that the colour layer consists substantially of polyester. 9. Sports floor as claimed in claim 1, characterized in that the layer for activation is arranged in a corresponding pattern of grooves in the floor. 10. Sports floor as claimed in claim l, characterized in that the layer for activation consists of a cured slurry. 11. Sports floor as claimed in claim 1, characterized in that the floor, at least in the region of the line marking, is covered by a transparent or opal top coat. 12. Sports floor as claimed in claim 1, characterized in that the line marking displays locally an intersecting of two lines, at the position of which the layer for activation is interrupted in both lines on both sides. 13. Method for providing a sports loor as claimed in claim 6 with line marking, comprising the steps of: (1) providing a sports floor, for instance of wood; (2) arranging a pattern of grooves, for example by cutting, corresponding to the desired line marking; (3) laying heating elements, for instance wires, in these grooves; (4) covering these heating elements with the colour layer, for instance a liquid, curable polyester; (5) arranging thereover the layer for activation, for example a curable slurry; and (6) coupling connecting means to the heating elements for connection to energizing means. *****

Inventors: NIJENHUIS JAN, NIJENHUIS, JAN
Applicants: MULDER HARMINA, NIJENHUIS JAN, MULDER, HARMINA, NIJENHUIS, JAN
Application year: 1990
Main classification: A63C19
IPC codes: A63C19