GB2252242A - A clamping device for artificial turf. - Google Patents

Description

1 2252242 A CLAMPING DEVICE FOR ARTIFICIAL TURF The present invention

relates to a clamping device for artificial turf and similar coverings.

Sports fields and other surfaces in similar use are often overlaid with artificial turf or other ground coverings to provide surface characteristics appropriate to specific requirements.

Such coverings are especially desirable for surfaces subject to severe wear and tear.

When a sports field, for example, is covered with artificial turf, it is important for the turf to be laid precisely and firmly, so that it cannot be displaced and will remain permanently fixed in position. Special problems are presented by the marginal regions, where the artificial turf must be firmly anchored to the underlying surface.

Another problem is that the anchoring device should not present any risk of injury to the sportsman or other user of the surface, especially since one purpose of the artificial turf is that its elasticity should prevent such injuries.

Diverse clamping devices for artificial turf and other ground coverings are known, but these have various disadvantages.

German Patent Specifications DE 31 43 476 A1 and DE 89 13 129 U1 describe clamping devices in which the margin of the artificial turf is pressed, by means of a rail, onto a receptacle fixed to the ground, the clamping action being brought about by the screwing of the rail to the receptacle. This known device is disadvantageous in that on the one hand, it is laborious to construct and, on the 2 other hand, great effort is required to clamp the margins in place because many of the bolts must be screwed tight before the marginal section is securely held. While the bolts are being tightened, the margin of the covering must be pressed down, so that several people are needed for the assembly. Furthermore, it is very difficult to pull the artificial turf or other covering taut.

In German Patent Specification DE 32 41 691 C2 a clamping device is described in which the marginal section is stuck into an essentially vertical slit in a receptacle fixed in the ground, and the margin is secured within the slit by means of a wedge-shaped clamping device. So that the covering will be held more firmly, sawteeth pointing against the direction of pull are provided. This clamping device requires that the marginal section have a relatively high elasticity perpendicular to its surface, in order that the clamping rail can be pushed into the slit in the receptacle together with the marginal section. Because of this elasticity, however, the marginal section is likely to slide out of its clamp-mounting when strong pulling forces are applied. Furthermore, with this known clamping device there is very little opportunity for pulling the covering taut while the margin is being fixed. Finally, it is extremely difficult to reopen the clamping device once a margin has been clamped in place, and during opening the margin of the artificial turf is likely to be damaged. But such later opening of the clamping device is always necessary when the artificial turf becomes slack or develops folds or bulges, so that it has to be pulled taut again.

The object of the present invention is to provide a clamping device so artificial turf can be securely fixed and released by simple means.

a 3 According to the present invention there is provided a clamping device for artificial turf or similar covering for the ground or another base comprising a clamp rail which, together with a marginal section of the covering can be fixed within a receptacle in order to hold the covering in place, the clamp rail comprising a holding means constructed to retain the margin of the covering so that it can be fixed in or onto the clamp rail, and the receptacle comprising a locking wall formed to define a wedge shape so that the clamp rail, when set into the receptacle together with the margin, is retained in the receptacle against tractile forces exerted through the covering by the locking wall.

is Thus in the invention, the marginal section of a strip of artificial turf or other covering can be fixed in the clamp rail, which is then set into the receptacle together with the covering and held there by the wedge- shaped locking wall. Hence, the entire clamping device is both very simply produced and particularly simple to use. Because the marginal section is fixed prior to the final assembly, the ground covering can be pulled or stretched while it is being mounted in the receptacle.

Preferably, the holding means comprises a receiving space defined within the clamp rail which is open to the exterior by way of an insertion opening so that the marginal section can be inserted into the receiving space through the insertion opening and held firm against the direction of the tractile force by being rotated or folded over against the surface of the covering. Hence, with the covering thus folded over it, the clamp rail is fixed with respect to forces parallel to the surface, so that the ground covering can be pulled taut.

Preferably also, the insertion opening comprises a 4 channel so that the marginal section can be inserted into the rail to a predetermined depth. This precaution ensures that the fold in the marginal section does not simply straighten out but is retained even under relatively strong pulling forces.

Preferably also, the clamp rail is made fabricated from a sheet material to define a substantially G-shaped profile. It can thus be economically manufactured in lengths to be sold by the meter and because of its light weight is easily handled during installation.

is Preferably also, the insertion opening is set back from a locking face of the clamp rail so that when the locking face is brought into register with the locking wall a gap is left to accommodate the marginal section of the covering. In this way, even a relatively thick ground covering, in particular an artificial turf, can be introduced into the rail and set into the ground so that the whole clamping device is covered by the artificial turf. Thus all risk of injury by the clamping device is avoided.

Preferably also, the clamp rail comprises a series of holes shaped and arranged so that when the clamp rail has been set into the receptacle a lifting means can be used to locate in one or more of the holes to enable the clamp rail to be lifted out of the receptacle. The holes are preferably elongate in shape so that they can be easily located by probing with a sharp object and the lifting means preferably comprises hooks which can be inserted into the holes and used to lift the clamp rail upward out of the receptacle.

Preferably also, the receptacle comprises a bracing wall which in use is substantially vertically oriented. In use, a correspondingly shaped bracing face of the clamp rail lies against this bracing wall, so that the tractile forces exerted by the ground covering upon the clamp rail are opposed.

Preferably also, the locking wall is constructed so that its upper edge extends into the insertion opening when the clamp rail is set into the receptacle. As a result the insertion opening can be made smaller, which reduces the freedom of movement of the clamped marginal section.

is Preferably also, the locking wall is dimensioned such that within the insertion opening the upper edge clamps the marginal section of the covering against a cover piece of the clamp rail that forms the upper boundary of the insertion opening. Thus because the locking wall is wedgeshaped, the clamping action and hence the holding force is enhanced when tractile forces are exerted.

Preferably also, the receptacle is constructed from a sheet material and is provided with at least one anchor foot attached to its lower surface in such a way that the receptacle can be thereby anchored in a concrete bed. In this way the clamping device can be be used independently of all subsequent building elements, such as drainage gutters or kerbstones, and even regardless of whether any such subsequent building elements are planned. This aspect makes the clamp rail suitable for every application. Hence it is possible to manage with only one kind of clamp rail, one which is easy to handle and can be cut to any desired length. As a result, the production and storage costs can be kept low.

It is also possible to incorporate the receptacle in the channel or grating of a drainage gutter. Another possibility is to incorporate one part of the receptacle, 6 such as its bracing wall, in the channel unit and another part, such as its locking wall, in the grating. The receptacle can also be combined with or incorporated in a kerbstone.

The present invention will now be described by way of example with reference to the accompanying drawings, wherein:

Fig. 1 is a cross section through a preferred embodiment of a receptacle forming part of a clamping device according to the invention; Fig. 2 is a view of the receptacle along the line II is II in Fig. 1; Fig. 3 is a cross section through a preferred embodiment of a clamp rail for use with the receptacle shown in Figs 1 and 2; Fig. 4 is a view along the line IV-IV in Fig. 3; Figs. 5a to 5f show in cross section steps in the procedure by which a clamping device comprising the receptacle and clamp rail shown in Figs. 1 to 4 is assembled and used; Fig. 6 is a cross-sectional view of a second embodiment of the invention; z Fig. 7 is a partial cross-sectional view of a modified embodiment; and Figs. 8 and 9 are cross-sectional views of third and fourth embodiments of the invention.

7 In the following description the same reference numbers are used f or components that are the same or have the same actions in the various embodiments of the invention.

In the preferred embodiment of the invention shown in Figs. 1 to 4, the clamping device comprises a receptacle 10 consisting of a profile element formed from sheet metal 14, which has either been made corrosion-proof by a suitable surface coating or is itself corrosion-proof.

The profile element 14 has a substantially horizontal bottom 13 with a substantially vertical bracing wall 12 on one side and a locking wall 11 on the other side. The locking wall 11 is inclined toward the bracing wall 12, defining a wedge shape. The upper edge 16 of the locking wall 11 is a smaller distance from the bottom 13 than is the rim 17 of the bracing wall.

From the lower surface of the bottom 13 of the profile element 14 and distributed along the entire length of the profile element 14, substantially vertical anchor feet 15 project. As an additional feature which can be provided if desired, openings (not shown) can be provided in the bottom 13 or at the transition from the bottom 13 to the locking wall 11 or the bracing wall 12, to allow water to drain out.

The clamping device also comprises a clamp rail 20, fabricated from sheet metal. The clamp rail is essentially G-shaped in cross section, with a base 23 corresponding to the bottom 13 of the receptacle 10. On one side of the base 23 and substantially perpendicular to it is a bracing face 22, and at right angles to the bracing face 22 is a cover piece 27, which is substantially parallel to the base 23. On the side opposite the bracing face 22, the 8 profile of the rails 20 is bent to form a substantially semicircular locking face 21 and a channel-wall section 29, which is substantially parallel to the base 23 and to the cover piece 27. The channel-wall section 29 projects into a receiving space 24 within the clamp rail 20.

The channel-wall section 29 is separated from the cover piece 27 by a distance forming an insertion opening 25.

The free edge 19 of the cover piece 27, opposite the bracing face 22, is set back from the locking face 21 as indicated by the dashed line in Fig. 3. As a result, when the clamp rail 20 is set into the receptacle 10 a space 26 is left free. In the cover piece 27 of the clamp rail 20, near the bracing face 22, longitudinally extending holes 28 are provided. The holes 28 are located at several specific positions with respect to the overall length of the clamp rail 20, for example, in the middle of the rail and a short distance away from its ends.

The assembly of a clamping device comprising the receptacle 10 and the clamp rail 20 as shown in Figs. 1 to 4 will now be described with reference to Figs. 5a to 5f.

In this example, the installation of the clamping device to hold an artificial turf on a previously constructed sports field is described.

First, the ground of the sports field is excavated next to a gutter 30 or other edging for a width of about 10 cm from the edging or existing concrete support for the gutter 30. The depth of the excavation should be sufficient to accommodate a concrete bed of a depth with room to hold the anchor feet 15 of the receptacle 10.

Concrete is poured into the excavation up to a level just below the rim of the gutter 30. Then a line of receptacles 9 is pressed into the fresh concrete so that their rims 17 are substantially at the same level as the rim of the gutter 30. A receptacle 10 embedded in concrete 2 in the ground 1 is shown in Fig. 5a.

After the receptacles 10 have been embedded, the surface of the sports field is prepared. Strips of artificial turf are laid and stretched as necessary and the turf is cut so that it extends beyond the receptacle 10 by a certain amount, as shown to scale in Fig. 5b by the arrow a. The upper surface of the sports field should be level with the rim 17 of the receptacle 10.

is The underlayer 5 of the artificial turf 3 is now removed over a distance a + b, as shown in Fig 5b, so that in this marginal region only the grass pile 4 and a backing layer remain. A series of parallel cuts, which are not shown, is also made in this marginal region inwards from the edge of the turf 5, the distance between the cuts corresponding to the length of a clamp rail 20.

After these cuts have been made, the clamp rail 20 is slipped over the margin 6 as shown in Fig. 5c, so that the margin 6 extends through the insertion opening 25 into the receiving space 24 of the clamp rail 20 so that the edge of the margin 6 meets the inside of the bracing face 22. During this procedure the base 23 of the clamp rail 20 is upward and the cover piece 27 lies directly below the margin 6.

Now, as indicated in Figs. 5c and 5d, the clamp rail 20 is turned over so that the cover piece 27 comes to rest against the underside of the elastic underlayer 5 of the artificial turf 3.

The clamp rail is now rotated further as shown in Fig.

5e, so that its locking face 21 can slide into the receptacle 10 under the wedge-shaped locking wall 11. The direction of movement is shown by the arrow in Fig. 5e.

Finally, the clamp rail 20 is completely inserted into the receptacle 10 by pushing down on its bracing face 22, as indicated by the double arrow in Fig. 5e, so that the bracing face 22 is completely in contact with the bracing wall 12 of the receptacle, while at the same time the locking face 21 of the clamp rail 20 slides down along the slanting part of the locking wall 11. During this procedure the upper edge 16 of the receptacle 10 is driven into the artificial turf 3, pressing the latter firmly against the inside of the cover piece 27, as shown in Fig.

is 5f. With a clamp assembled in this way, the artificial turf is pulled taut and simultaneously held firmly in place, by both the rotation of the rail 20 and the clamping action of the upper edge 16.

To release the rail 20 from the receptacle, for example in order to smooth the artificial turf or carry out other work, the holes 28 in the clamp rail 20 are first found by probing with a nail, small screwdriver or similar device. Lifting hooks (not shown) are then held parallel to the rail 20 with their tips over the holes and pressed down so that the tips pass through the artificial turf and into the holes. Then the handles of the hooks are raised and the hooks are rotated through 90. As the hooks are lifted, the rail 20 is pulled up with the bracing face 22 being lifted first and one can proceed in reverse order through the steps shown in Figs. 5f and 5e. As soon as the rail 20 has been lifted out of the receptacle 10, it can be easily removed and the necessary work carried out.

l As will now be described with reference to Figs. 6 to 9, the receptacle 10 can be made not only as a separate 11 component of the clamping device, as described above with reference to Figs 1 and 2, but also as an integral part of a precast structure, for example as part of a drainage gutter 30, a kerbstone or other independently required boundary structure, which is already present or which must be installed for its own purpose.

In the embodiment shown in Fig. 6, the drainage gutter 30 comprises a channel section 31 covered by a grating 32, mounted in known manner, which rests on bearing surfaces 33, 34 of the channel section 31. The part of the grating 32 next to the slits 35 is stamped or bent to form the receptacle 10.

As will be appreciated and as can be seen by comparing the differing embodiments shown in Figs. 6 and 7, the receptacle 10 can be incorporated into the grating 32 in various positions.

Figs. 8 and 9 show drainage gutters 30 in which not only the channel section 31 but also the grating 32 or other cover provided with slits 35 is made of concrete.

In the example of an embodiment shown in Fig. 8, the receptacle 10 is integral with the channel unit 31.

Because the locking wall 11 forms a recess, to manufacture such a channel unit 31 either the material must be poured into a mould consisting of several parts or during pouring a wedge-shaped part, made for example of a foam material, must be included which can be removed after the channel unit has hardened.

In the embodiment shown in Fig. 9, the bottom 13 and the bracing wall 12 are formed by the channel unit 31, while the locking wall 11 is formed by the grating 32.

This arrangement avoids the problem of having to make a 12 recess in a casting mould and also provides drainage for the receptacle 10. Furthermore, if in this embodiment the length of the clamp rail 20 is made appropriately larger than the lengths of the gratings 32, when one grating 32 is removed (e.g., to clean the gutter) the associated rail will still be kept in place by another (in the middle of the rail 20) or the two adjacent gratings 32 (at the ends of the rail).

1.

ThusP from the foregoing it will be appreciated that the advantage of the present invention over the prior art resides in the cooperation of the clamp rail 20 with the receptacle 10 having its wedge-shaped recess positioned on the outer side of the receptacle 10, so that the forces is exerted on the clamp rail 20 by the artificial turf or another corresponding ground covering pull the clamp rail 20 upward in such a way that these torque forces are opposed by the wedge-shaped locking wall 11.

13

Claims (12)

1. A clamping device for artificial turf or similar covering for the ground or another base comprising a clamp rail which, together with a marginal section of the covering can be fixed within a receptacle in order to hold the covering in place, the clamp rail comprising a holding means constructed to retain the margin of the covering so that it can be fixed in or onto the clamp rail, and the receptacle comprising a locking wall formed to define a wedge shape so that the clamp rail, when set into the receptacle together with the margin, is retained in the receptacle against tractile forces exerted through the covering by the locking wall.

2. A clamping device as claimed in Claim 1, wherein the holding means comprises a receiving space defined within the clamp rail which is open to the exterior by way of an insertion opening so that the marginal section can be inserted into the receiving space through the insertion opening and held firm against the direction of the tractile force by being rotated or folded over against the surface of the covering.

3. A clamping device as claimed in Claim 2, wherein the insertion opening comprises a channel so that the marginal section can be inserted into the rail to a predetermined depth.

4. A clamping device as claimed in Claim 2 or Claim 3, wherein the clamp rail is made fabricated from a sheet material to define a substantially G-shaped profile.

5. A clamping device as claimed in any one of Claims 2 to 4, wherein the insertion opening is set back from a locking face of the clamp rail so that when the locking face is 14 brought into register with the locking wall a gap is left to accommodate the marginal section of the covering.

6. A clamping device as claimed in any one of Claims 1 to 5, wherein the clamp rail comprises a series of holes shaped and arranged so that when the clamp rail has been set into the receptacle a lifting means can be used to locate in one or more of the holes to enable the clamp rail to be lifted out of the receptacle.

7. A clamping device as claimed in any one of Claims 1 to 6, wherein the receptacle comprises a bracing wall which in use is substantially vertically oriented.

is

8. A clamping device as claimed in any one of Claims 2 to 7 when dependent on Claim 2, wherein the locking wall is constructed so that its upper edge extends into the insertion opening when the clamp rail is set into the receptacle.

9. A clamping device as claimed in Claim 8, wherein the locking wall is dimensioned such that within the insertion opening the upper edge clamps the marginal section of the covering against a cover piece of the clamp rail that forms the upper boundary of the insertion opening.

10. A clamping device as claimed in any one of Claims 1 to 9, wherein the receptacle is constructed from a sheet material and is provided with at least one anchor foot attached to its lower surface in such a way that the receptacle can be thereby anchored in a concrete bed.

11. A clamping device as claimed in any one of Claims 1 to 10, wherein the receptacle is formed as part of a channel unit and/or a grating of a drainage gutter.

12. A clamping device for artificial turf or similar covering for the ground or another base substantially as hereinbefore described with reference to any of Figs. 1 to 5, Fig. 6, Fig 7, Fig 8, or Fig. 9 of the accompanying drawings.