Title:
Drainage device
Kind Code:
A1


Abstract:
The invention discloses a drainage device for surface drainage, in particular a drainage channel, comprising a, preferably elongate, basic element (12), a lid (22), preferably a cover grate, covering an opening (16) in the basic element (12), and comprising at least one locking engagement means (38, 40) for the locking engagement of the lid (22) to the basic element (12), the engagement means (38, 40) comprising at least one first element (42) for locking to the basic element (12) and at least one second locking element (44), which is integral with the lid (22) and may be brought into directly locking engagement with the first locking element (42). The unique feature of the invention is that at least one projection (34, 36), which protrudes in the direction of the base (18) of the basic element (12) and holds the second locking element (44), is substantially rigidly secured to the lid (22).



Inventors:
Neuber, Wilfried (Wildeshausen, DE)
Application Number:
10/545539
Publication Date:
06/28/2007
Filing Date:
02/12/2004
Primary Class:
International Classes:
E03F5/06
View Patent Images:
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Primary Examiner:
HARTMANN, GARY S
Attorney, Agent or Firm:
Mueting, Raasch & Gebhardt, P.A. (Minneapolis, MN, US)
Claims:
1. 1-22. (canceled)

23. A drainage device for surface drainage, comprising: an elongate basic element; a lid configured to cover an opening in the basic element; and an engagement arrangement configured to facilitate locking engagement of the lid to the basic element, the engagement arrangement comprising: at least one first locking element being arranged on the basic element; and at least one second locking element integral with the lid and configured to be brought into locking engagement with the first locking element, at least one projection, which protrudes in a direction of a base of the basic element, being integrally formed on the lid and the second locking element being arranged on a portion of the projection that is remote from the lid, wherein the portion of the projection that is remote from the lid is wider than a remaining portion of the projection and substantially has a shape of a rod extending substantially parallel to a plane of the lid.

24. The device according to claim 1, wherein one or both of a portion of the projection that holds the second locking element and at least a portion of the basic element that holds the first locking element is resilient in configuration at least in a direction at an angle to the plane of the lid.

25. The device according to claim 1, wherein one or both of at least a portion of the projection that holds the second locking element and at least a portion of the basic element that holds the first locking element is located in a direction at an angle transverse to a longitudinal extent of the basic element.

26. The device according to claim 1, wherein the projection is integrally formed on the lid.

27. The device according to claim 1, wherein the lid comprises ribs, and the projection is formed by at least one of the ribs or is formed integrally on at least one of the ribs.

28. The device according to claim 27, wherein the ribs are configured, at least in part, as transverse ribs extending between longitudinal sides of the lid, wherein the projection is formed by at least one of the transverse ribs or is formed integrally on at least one of the transverse ribs.

29. The device according to claim 1, wherein the first and second locking elements comprise complementary recesses and projections configured to be brought into mutual engagement.

30. The device according to claim 29, wherein the first locking element comprises a ridge and the second locking element comprises a complementary groove.

31. The device according to claim 1, wherein the first and second locking elements comprise locking noses configured to be brought into mutual engagement.

32. The device according to claim 1, wherein: the basic element comprises at least one bearing surface for the lid; an indentation is formed in a region of the bearing surface; and the first locking element is arranged within the indentation.

33. The device according to claim 32, wherein the projection is configured such that, in an assembled state of the drainage device, the second locking element protrudes into the indentation in the basic element and is in locking engagement with the first locking element.

34. The device according to claim 1, wherein the basic element comprises a skirt configured to receive the lid, and the first locking element is integrated into the skirt.

35. The device according to claim 1, wherein the lid comprises a cover grate.

36. A drainage device for surface drainage, comprising: an elongate basic element; a lid configured to cover an opening in the basic element; means for displaceably arranging the lid on the basic element; and means for retentively engaging the lid and the basic element, the engaging means comprising at least one pair of engagement arrangements that may be brought into mutual engagement, of which a first engagement arrangement is provided on the lid and a second engagement arrangement is provided on the basic element.

37. The device according to claim 36, wherein the first engagement arrangement comprises at least one nose and the second engagement arrangement comprises at least one recess for receiving the at least one nose.

38. The device according to claim 36, wherein the second engagement arrangement comprises at least one nose and the first engagement arrangement comprises at least one recess for receiving the at least one nose.

39. The device according to claims 38, wherein the at least one nose rises from a bearing surface of the basic element and the at least one recess on a lower side of the lid forms a corresponding indentation.

40. The device according to claim 36, wherein the basic element comprises at least one bearing surface for the lid, the first engagement arrangement is configured on a lower side of the lid, and the second engagement arrangement is configured on the bearing surface of the basic element.

41. The device according to claims 40, wherein the second engagement arrangement comprises at least one nose and the first engagement arrangement comprises at least one recess on the lower side of the lid for receiving the at least one nose, wherein the at least one nose rises from the bearing surface and the at least one recess forms a corresponding indentation.

42. The device according to claim 39, wherein the lid comprises ribs, with edge portions of which the lid rests on the bearing surface on the basic element, and at least one recess is formed between two adjacent edge portions of the ribs.

43. The device according to claim 36, wherein the basic element comprises at least one side wall portion, and the means for displaceably arranging the lid comprises at least one stop for abutment with the at least one side wall portion.

44. The device according to claim 43, wherein the basic element comprises at least one bearing surface for the lid, below which the at least one side wall portion is located, and the stop is configured to form an extension arranged on a lower side of the lid.

45. The device according to claim 38, wherein the basic element comprises a skirt, which serves for receiving the lid, and the second engagement arrangement is configured on the skirt.

Description:

The invention relates to a drainage device for surface drainage, in particular a drainage channel, comprising a, preferably elongate, basic element, a lid, preferably a cover grate, covering an opening in the basic element, and comprising at least one locking engagement means for the locking engagement of the lid to the basic element, the engagement means comprising at least one first element for locking to the basic element and at least one second locking element, which is integral with the lid and may be brought into directly locking engagement with the first locking element.

Drainage devices of the generic type are used, in particular, in traffic surfaces for motor vehicles, cyclists or pedestrians and are configured, for example, as drainage channels. In order to facilitate assembly, maintenance and cleaning, it must be possible easily to remove and replace the cover grate of the drainage device. In opposition to the requirement that the cover grate be as easy to handle as possible, there is the need to prevent the cover grate from becoming accidentally detached, in order to avert the risk of accidents. Frequent use or continuous mechanical loads, for example caused by vehicle traffic, should, if possible, also not loosen the attachment of the cover grate. The phrase “resiliently configured in a direction at an angle to the plane of the lid” refers to the fact that, when a force is exerted, the portion holding the second locking element and/or the portion holding the first locking element is subjected, owing to the flexibility caused by the resilience, to a swivelling movement in a direction at an angle to the plane of the lid, a restoring moment being produced in precisely the opposite direction as a result of the resilience.

The prior art discloses a large number of fastening means, which are intended to bring about such securing of the cover grate to the drainage device. In addition to systems in which the cover grate is screwed to the drainage device, EP 0811 732, for example, discloses a cover grate wherein the cover grate is intended to be laterally fixed by means of clamping using specially configured, longitudinally resilient webs. In the locked state, cams arranged at movable ends of the longitudinal webs engage with corresponding laterally arranged recesses in the basic element.

A drawback of the known drainage devices is that they often require specific tools for locking the cover grate to the basic element. Moreover, although the locking devices, which are in some respects very complex, allow secure abutment of the cover grate with the channel element, during maintenance, they may only be removed with a high degree of effort. Simply as a result of the purpose to which such devices are put, sediments consisting of soil, sand and organic material are deposited in each recess in the drainage device that is accessible from the surface. In the case of conventional drainage devices, it is precisely in these regions that most of the actuating and locking elements for locking the cover grate to the basic element of the drainage device are located.

It is therefore the object of the present invention to provide a drainage device for surface drainage of the generic type, wherein the cover grate may be locked to the basic element in a particularly simple, but also reliable manner. The use of special tools for assembly or subsequent maintenance of the drainage device should, in particular, be dispensed with. Moreover, the locking device should also be configured such that it is easily detachable and may easily be cleaned even when substantial amounts of sediments have been deposited.

This object is achieved by the drainage device for surface drainage having the features recited in claim 1.

The drainage device for surface drainage, in particular a drainage channel, comprises a basic element, a lid covering an opening in the basic element and at least one locking engagement means for the locking engagement of the lid to the basic element. The locking means comprises at least one first element for locking to the basic element and at least one second locking element, which is integral with the lid and may be brought into directly locking engagement with the first locking element. It is provided that the generic drainage device is developed such that at least one projection, which protrudes in the direction of the base of the basic element and holds the second locking element, is substantially rigidly secured to, preferably integrally formed on, the lid. As a result of the specific position and configuration of the locking means, the cover grate may still be used even when substantial amounts of soil, sand or organic material have been deposited. The locking elements of the engagement means are integral parts of the lid or basic element; no further engagement elements, such as screws, clamps and the like, are therefore required for the locking process.

According to a preferred configuration of the invention, at least a portion of the projection that holds the second locking element and/or at least a portion of the basic element that holds the first locking element is resilient in its configuration, preferably in a direction at an angle to the plane of the lid. This allows the locking of the two locking elements to be assisted in a simple manner and facilitates the attachment of the lid to the basic element. Accordingly, in this configuration, the portions holding the first locking element and/or the second locking element may be swivelled in a resilient manner about a notional swivel axis, which preferably extends parallel to the plane of the lid or is located in said plane.

Moreover, it is preferred that the portions holding the first and/or second locking element each span a plane extending at an angle, preferably transversely, to the longitudinal extent of the basic element. Disengagement of the engagement means in the event of forces acting in the longitudinal direction on the lid of the drainage device is thus rendered more difficult or entirely prevented.

The lid preferably comprises ribs, in particular for the purpose of rigidification, the projection being formed by a rib or being arranged, preferably integrally formed, on a rib. In particular, the ribs are configured, at least in part, as transverse ribs extending between longitudinal sides of the lid, and the projection is located on these transverse ribs. In terms of production, the aforementioned embodiment of the engagement means may be provided in a particularly simple manner, so the overall manufacturing costs of the drainage device may be reduced.

In a preferred configuration of the invention, the first and second locking elements comprise complementary recesses and swellings. Said recesses and swellings may preferably be configured such that the first element for locking to the basic element has a ridge, and the second locking element a complementary groove. The configurations of the locking elements, which are in principle very simple to provide during production and are thus associated with low manufacturing costs, have proven highly robust with respect to environmental influences and mechanical loads. If the device should become soiled or sediments be deposited in the region of the locking elements, cleaning of the locking elements, for example by means of high-pressure water cleaning, is particularly simple, as all of the constituent parts of the locking means are easily accessible.

However, other constructional possibilities are also conceivable for bringing the first and second locking elements into mutual locking engagement. Thus, for example, the first and second locking elements may alternatively comprise locking noses that may be brought into mutual engagement. The locking noses of the first and second elements are usually aligned with each other and interlock in the locking position, and thus in the closed state of the engagement means.

It is also preferred that the basic element comprises at least one bearing surface for the lid, an indentation being formed in the region of the bearing surface and the first locking element being arranged within the indentation. If the basic element comprises a skirt, which serves to receive the lid, then the first locking element is preferably integrated into the skirt. The aforementioned measures allow displacement of the cover grate owing to mechanical loads in the longitudinal direction to be prevented. The assembly and repositioning of the cover grate on the basic element after maintenance is also facilitated, as the configuration of the locking elements assists the pre-positioning of the cover grate on the basic element. In the assembled state of the drainage device, the second locking element protrudes into the indentation in the basic element and is in locking engagement with the first locking element.

It is also preferred that the second locking element is arranged on the portion of the projection that is remote from the lid. The portion of the projection that is remote from the lid may expediently be wider than the remaining portion of the projection and preferably have the shape of a rod located substantially parallel to the plane of the lid.

In a further preferred configuration of the invention, a means is provided for displaceably arranging the lid on the basic element. A means of this type allows the lid to be fixed to the basic element such that it may not be displaced with respect to the basic element if forces are introduced into the lid, in the direction of the extent thereof, as a result of external influences. Such forces acting in the longitudinal and/or transverse direction occur primarily when vehicles drive over the lid. Particularly high forces of this type are produced during deceleration or acceleration, in particular. As a result of such forces, the lid tends to become displaced with respect to the basic element. The engagement means is thus subjected to increased loads, and there may be a risk of more rapid wear or even damage. The aforementioned means, on the other hand, provides a system for the prevention of accidental displacement in that it absorbs the forces introduced into the plane of the lid and thus relieves the engagement means.

A development of the aforementioned configuration is distinguished in that the means for displaceably arranging the lid comprises at least one pair of engagement means that may be brought into mutual engagement, of which the first engagement means is arranged on the lid and the second engagement means is arranged on the basic element. The first engagement means may comprise at least one nose and the second engagement means at least one recess for receiving at least one nose; however, an inverse configuration is also conceivable. If the basic element is provided with at least one bearing surface for the lid, the first engagement means may expediently be configured on the lower side of the lid, and the second engagement means on the bearing surface of the basic element. In a particularly preferred development, the nose rises from the bearing surface and the recess on the lower side of the lid forms a corresponding indentation, with which the nose engages in order to fix the lid to the basic element in a non-displaceable manner with respect to the bearing surface. If the lid comprises ribs, with the edge portions of which the lid rests on the bearing surface on the basic element, at least one recess may preferably be formed by the gap between two adjacent edge portions of the ribs.

Conventionally, the basic element comprises at least one side wall portion; in this case, the means for displaceably arranging the lid may, alternatively or additionally to the above-described configuration, comprise at least one stop for abutment with the side wall portion, in order to form a further displaceable locking means. Provided that the basic element comprises at least one bearing surface for the lid, below which the side wall portion is located, the stop may form an extension arranged on the lower side of the lid.

Finally, if the basic element comprises a skirt, which serves to receive the lid, the second engagement means is expediently configured on the skirt.

Further preferred configurations of the invention also emerge from the features recited in the sub-claims.

The invention will be described below in greater detail with reference to an embodiment and a plurality of drawings, in which:

FIG. 1 is a plan view of a drainage channel for surface drainage according to a first embodiment;

FIG. 2 is a sectional view, taken along the line II-II, through the drainage channel according to FIG. 1;

FIG. 3 is a sectional view, taken along the line III-III, through the drainage channel according to FIG. 1;

FIG. 4 is an enlarged detail of the drainage channel according to FIG. 1, in the region of the locking elements of an engagement means, along the line IV-IV;

FIG. 5 is a lateral, half-sectional view of a cover grate for a drainage channel according to a second embodiment;

FIG. 6 is a cross section through the cover grate according to FIG. 5;

FIG. 7 is a perspective bottom view of the cover grate according to FIG. 5; and

FIG. 8 is a view, perspective in certain regions, of a portion of a skirt of a basic element of the drainage channel according to FIG. 1.

FIG. 1 is a schematic plan view of a drainage channel 10 for surface drainage according to a first embodiment, such as is typically used in traffic surfaces. The drainage device 10 is composed of a cover grate 22 and a basic element 12. Of the basic element 12, the perspective view of FIG. 1 shows merely a frame 14 extending in the longitudinal direction of the drainage device 10. The upper sides of the cover grate 22 and the frame 14 form a plane, which serves as a traffic surface.

Details regarding the structure of the basic element 12 may be inferred from FIG. 2 and FIG. 3, which are lateral views along the lines II-II and III-III of FIG. 1. The basic element 12 comprises an elongate opening 16, which is located in the plane of the traffic surface, merges with the channel element 17 and is covered by the cover grate 22 in the assembled state of the drainage channel 10. Water infiltrating through the opening 16 is collected at the base 18 of the channel element 17 and discharged.

It is also apparent from FIGS. 2 and 3 that the basic element 12 according to the illustrated embodiment comprises a skirt 19 that is attached to the channel element 17. FIG. 8 shows an enlarged detail of the skirt 19. As may be seen from FIGS. 3 and 8, the skirt 19 forms, at its sides directed toward the inside of the basic element 12, a shoulder 20, which is in each case downwardly set apart from the plane of the traffic surface. This shoulder 20 comprises a planar, horizontally oriented upper side, which acts as a bearing surface 21 for the cover grate 22. For the purposes of sound absorption, a resilient plastics material insert 24, which protrudes from the upper side of the shoulder, is conventionally provided. The basic element 12 may, for example, be made of concrete and the skirt 19 of a corrosion-resistant metal or plastics material.

In the illustrated embodiment, the plane 15 of the traffic surface of the cover grate 22 is formed by an outer peripheral web 26, five longitudinal openings 27 and four parallel longitudinal webs 28 at a corresponding mutual distance from one another. The peripheral web 26 widens slightly at its two longitudinal ends and is located, in the assembled state of the drainage device 10, as may be seen in the cross section of FIG. 3, with its lower side on the bearing surface 21 of the elongate projections 20 or on the resilient plastics material inserts 24 thereof.

Below the peripheral and longitudinal webs 26, 28 forming the traffic surface of the cover grate 22, transverse ribs 32 extend between the longitudinal sides of the cover grate 22 (only partly visible in FIG. 1). The transverse ribs 32 are integrally connected to the further elements of the cover grate 22, i.e. in particular the peripheral and longitudinal webs 26; 28, and are used substantially for rigidifying the cover grate 22.

The cross section illustrated in FIG. 2, taken along the line II-II of FIG. 1, shows a relative position of the individual transverse ribs 32 in the cover grate 22. Two of the transverse ribs 32 shown in cross section in FIG. 2 are provided with lugs or projections 34, 36 which point toward the base 18 of the basic element 12 and on which engagement means 38,40 are arranged. Engagement means may, of course, also be provided on further transverse ribs 32.

FIG. 4 shows, by way of example, an enlarged detail of the drainage device 10 in the region of the engagement means 40, along the line IV-IV of FIG. 1. The engagement means 40 comprises a first element 42 for locking to the basic element 12 and a second element 44 for locking to the cover grate 22, which second element may be brought into directly locking engagement with the first locking element 42.

According to the illustrated first embodiment, the first locking element 42 is configured as a ridge extending transversely to the longitudinal extent of the basic element 12 and is located substantially in the centre of a side wall 50 of a downwardly directed U-shaped portion 50, which is provided on the inside of the skirt 19 and forms an indentation or a kind of bead in the shoulder 20. The side wall 50 holding the first locking element 42 spans a plane extending transversely to the longitudinal extent of the basic element 12.

According to the illustrated first embodiment, the second locking element 44 is configured as a groove that extends transversely to the longitudinal extent of the basic element 12 and is complementary to the ridge of the first locking element 42; the second locking element 44 is arranged on a side wall 56 of the projection 36 of the transverse rib 32. The projection (36) holding the second locking element 44 spans a plane extending transversely to the longitudinal extent of the basic element 12. Accordingly, in the illustrated first embodiment, the second locking element 44 is integrally connected to the cover grate 22. The second locking element 44, which is provided as a groove, is provided at both lateral ends 54a of a lower end portion 54 of the projection 36. As may be seen from FIG. 3, the two lateral ends 54a of the lower end portion 54 extend substantially over the entire width of the lid 22, while the remaining projection 36 is less wide.

In the case of the engagement means 38, 40 of FIG. 2, the individual locking elements 42, 40 are respectively arranged on side walls, which face away from one another, of the projections 34, 36, which hold said locking elements and are integrally formed on a transverse rib 32. Although the projections 34, 36 are substantially rigidly integrally formed, via the respective transverse rib 32, on the cover grate 22, they nonetheless possess a certain resilience, so they are subjected to a slight tension once the cover grate 22 has been locked, thus providing the necessary holding force for the engagement means 38, 40 and hence completing the locking process.

For assembly, the cover grate is placed onto the basic element 12, the engagement means 38, 40 facilitating precise positioning. Once the cover grate 22 has been placed, it is pressed perpendicularly downward, the first locking elements 42, which are configured as ridges, sliding via the side walls 56 of the transverse ribs 32 until they engage with the groove-like second locking elements 44. In order to facilitate assembly and to achieve the locking effect, the projection 36, which holds the second locking element 44, of the associated transverse rib 32 and/or the side wall 50, which holds the first locking element 42, of the U-shaped portion 52, which forms an indentation, of the skirt 19 are configured so as to yield in a resilient manner in a direction at an angle to the plane 15 of the cover grate 22.

In the illustrated embodiment, as may also be seen from FIG. 2, the two engagement means 38, 40 are configured mirror-symmetrically to each other in that the first locking elements 42, which are configured as a ridge, face one another and the second locking elements 44, which are configured as a groove, face away from one another. As a result, during the locking of the lid 22 to the skirt 19 of the basic element 12, the transverse ribs 32, which are provided with the second locking element 44, are subjected to a tilting movement toward one another; this, in turn, produces a torque acting in the opposing direction in order to achieve engagement of the second locking element 44 with the first locking element 42. In this way, one of the engagement means 38, 40 forms in each case a counter-bearing with respect to the other engagement means.

However, the engagement means 38, 40 may also, of course, be configured mirror-symmetrically to each other in the inverse effective direction. Finally, however, it is, in principle, conceivable to provide only one engagement means in the above-described manner and optionally to configure a stop, which is arranged at a distance from said engagement means and acts as a counter-bearing.

In addition to the illustrated configurations of the locking elements 42 and 44, means for locking the cover grate 22 to the basic element 12 that comprise complementary recesses and swellings on the transverse ribs 32 or on the basic element 12 may also be provided. A plurality of locking elements of this type may also be arranged on a transverse rib 32 and accordingly in the region of the basic element 12. In the case of the arrangement illustrated according to FIG. 4, for example, the left-hand side wall, seen from the viewer's perspective, of the transverse rib 32 or the indentation 52 may in each case hold a locking element. The arrangement of the locking elements in the region of walls located perpendicularly to the traffic surface has proven particularly beneficial, because the depositing of sediments in the region of the engagement means 38, 40 may thereby be markedly reduced.

FIGS. 5 to 7 show a cover grate 122 of a second embodiment of a drainage channel. This cover grate 122 is suitable for placement on a basic element, as described above with reference to FIGS. 1 to 4. The basic element 12 according to the first embodiment may therefore also be used for the second embodiment, which will be described below, without any fundamental alterations. The upper side of the cover grate 122 is configured in an identical or similar manner to that shown in FIG. 1 with reference to the cover grate 22 of the first embodiment. FIG. 5 shows the cover grate 122 with a left-hand partial longitudinal section along a line corresponding to the line II-II of FIG. 1, and FIG. 6 shows a cross section through the cover grate 122 along a line corresponding to the line III-III of FIG. 1.

This cover grate 122 differs from the cover grate 22 according to the first embodiment in that the transverse ribs 132 extend over the entire width of the cover grate 122, and the cover grate 122 rests on the bearing surface 21 of the basic element 12 only with the lateral end portions 132a of the transverse ribs 132. When the cover grate 122 abuts the bearing surface 21 of the basic element 12, gaps, where the cover grate 122 does not rest on the bearing surface 21 of the basic element 12, are thus formed between the end portions 132a of each pair of adjacent transverse ribs 132.

The lid 122 also differs from the first configuration in that the engagement means 138, 140 are configured differently. Although the locking means 138, 140 also have a locking function, in the case of the second configuration, the second locking elements 144 are configured as wedge-shaped locking projections. In the closed state, the second locking elements 144, which are configured as wedge-shaped projections, underlap the first locking elements, which are configured on the basic element 12, are arranged in an identical or similar manner to the first locking elements 42 in the first configuration, and are also configured in a similar manner as ridges or projections.

In the second configuration, similarly to as in the first configuration, the second locking element 144 is also located on a lower end portion 154 of the projection 134 or 136. However, in the second configuration, unlike in the first configuration, the second locking element is configured as a rod, which extends parallel to the plane of the cover grate 122 over the entire width of the cover grate 122, whereas the projection 134 or 136 holding the second locking element 144 is significantly less wide, as may be seen, in particular, from FIGS. 6 and 7.

In all other respects, the construction of the second embodiment substantially corresponds to that of the first embodiment, so further description is not required at this point.

Alternatively, however, it is also conceivable to arrange, for example by casting, a high-grade steel spring, which is biased on the basic element in the direction toward the first locking element and may be brought into engagement with said basic element, for example on the lower side of the cover grate or on the corresponding transverse rib.

As may also be seen from FIGS. 2 and 8, recesses 60 and 160, with which noses 62 correspondingly arranged on the basic element 12 engage, are formed on the lower side of the lid 22 or 122.

In FIG. 2, with respect to the first embodiment, the recesses 60 and the associated noses 62 are illustrated by broken lines, whereas in FIG. 5 only the noses 62 may be seen in perspective. In the first embodiment, two noses 62, which are set apart from each other, are arranged on the bearing surface 21 of the shoulder 20, which is configured on the skirt 19, so the noses 62 rise form the bearing surface 21 (cf., in particular, FIG. 5). Accordingly, in the illustrated embodiment, the associated recesses 60 are formed on the lower side of the peripheral web 26 of the lid 22. However, it is also conceivable to provide only one nose 62 on the basic element 12 and accordingly a recess 60 on the lid 22. It is also conceivable to provide more than two pairs of recesses 60 and noses 62. Conventionally, at least one nose 62, which engages with an associated recess 60 formed on the corresponding longitudinal side of the lid 22, is arranged on each longitudinal side of the basic element 12.

In the case of the second embodiment, on both longitudinal sides of the cover grate 122, the two recesses are each formed by a gap produced, when the lid 122 is placed onto the basic element 12, between a lateral end portion 133, which widens in the longitudinal direction of the cover grate 122, of a central transverse rib 132 and the lateral end portion 132a of the adjacent transverse ribs 132. The noses 62, which rise from the bearing surface 21 of the basic element 12, engage with these gaps, which act as a recess 160 (cf. FIG. 5). In the illustrated embodiment, the dimensions of the width of the widening lateral end portion 133, in the longitudinal direction of the cover grate 122, are such that said end portion substantially fits in the gaps formed between the two noses 62, which are arranged in a pair, so both noses 62 substantially abut this widening lateral end portion 133 in order to bring about a locking process with as little tolerance as possible, in order to achieve the desired displacement prevention. However, alternatively or additionally, it is also conceivable for the dimensions of the width of the recesses 160, in the longitudinal direction of the cover grate 122, to correspond to the width of the noses 62 engaging with said recesses.

Thus, when the lid 22 or 122 is placed onto the basic element 12, not only do the first and second locking elements engage for the locking engagement of the lid 22 or 122 to the basic element 12; the noses 62 on the basic element 12 also engage with the recesses 60 or 160 on the lower side of the lid 22 or 122. The arrangement consisting of a recess 60 or 160 and an associated nose 62 accordingly provides a displacement prevention means, which fixes the lid 22 or 122 with respect to the basic element 12 in order to prevent undesirable movements in the longitudinal direction. Such undesirable displacement may occur, in particular, when vehicles drive over the lid 22 or 122, thus resulting in increased loading of the locking means 38, 40 or 138, 140. The displacement prevention means formed by the noses 62 and the associated recesses 60 or 160, on the other hand, allows the engagement means 38, 40 or 138, 140 to be correspondingly relieved.

The above-described arrangement of recesses 60 or 160 and noses 62 serves substantially for non-displaceably locking the cover grate 22 or 122 in the longitudinal direction.

For non-displaceable locking in the transverse direction, further measures may, if required, be provided. In the case of the cover grate 122 according to the second embodiment, such measures are provided in the form of extensions 164. As may be seen from FIG. 7, these extensions 164 are formed integrally on transverse ribs 132 and extend downward. However, alternatively, it is also conceivable to arrange the extensions, for example, at a different location on the lower side of the cover grate. The extensions 164 are positioned such that they form a stop for abutment with the respective adjacent inner side wall portion 19a of the skirt 19 of the basic element 12, which is connected to said skirt below the bearing surface 21 (cf. FIGS. 3 and 8). However, it is also conceivable that the length of the extensions acting as a stop is such that said projections may be brought into abutment not only with the inner side wall portion 19a of the skirt 19, but also with the inner side wall portion 17a of the channel element 17 connected therebelow.

The invention relates to a drainage device for surface drainage, in particular a drainage channel, comprising a, preferably elongate, basic element, a lid, preferably a cover grate, covering an opening in the basic element, and comprising at least one locking engagement means for the locking engagement of the lid to the basic element, the engagement means comprising at least one first element for locking to the basic element and at least one second locking element, which is integral with the lid and may be brought into directly locking engagement with the first locking element.

Drainage devices of the generic type are used, in particular, in traffic surfaces for motor vehicles, cyclists or pedestrians and are configured, for example, as drainage channels. In order to facilitate assembly, maintenance and cleaning, it must be possible easily to remove and replace the cover grate of the drainage device. In opposition to the requirement that the cover grate be as easy to handle as possible, there is the need to prevent the cover grate from becoming accidentally detached, in order to avert the risk of accidents. Frequent use or continuous mechanical loads, for example caused by vehicle traffic, should, if possible, also not loosen the attachment of the cover grate. The phrase “resiliently configured in a direction at an angle to the plane of the lid” refers to the fact that, when a force is exerted, the portion holding the second locking element and/or the portion holding the first locking element is subjected, owing to the flexibility caused by the resilience, to a swivelling movement in a direction at an angle to the plane of the lid, a restoring moment being produced in precisely the opposite direction as a result of the resilience.

The prior art discloses a large number of fastening means, which are intended to bring about such securing of the cover grate to the drainage device. In addition to systems in which the cover grate is screwed to the drainage device, EP 0811 732, for example, discloses a cover grate wherein the cover grate is intended to be laterally fixed by means of clamping using specially configured, longitudinally resilient webs. In the locked state, cams arranged at movable ends of the longitudinal webs engage with corresponding laterally arranged recesses in the basic element.

A drawback of the known drainage devices is that they often require specific tools for locking the cover grate to the basic element. Moreover, although the locking devices, which are in some respects very complex, allow secure abutment of the cover grate with the channel element, during maintenance, they may only be removed with a high degree of effort. Simply as a result of the purpose to which such devices are put, sediments consisting of soil, sand and organic material are deposited in each recess in the drainage device that is accessible from the surface. In the case of conventional drainage devices, it is precisely in these regions that most of the actuating and locking elements for locking the cover grate to the basic element of the drainage device are located.

It is therefore the object of the present invention to provide a drainage device for surface drainage of the generic type, wherein the cover grate may be locked to the basic element in a particularly simple, but also reliable manner. The use of special tools for assembly or subsequent maintenance of the drainage device should, in particular, be dispensed with. Moreover, the locking device should also be configured such that it is easily detachable and may easily be cleaned even when substantial amounts of sediments have been deposited.

This object is achieved by the drainage device for surface drainage having the features recited in claim 1.

The drainage device for surface drainage, in particular a drainage channel, comprises a basic element, a lid covering an opening in the basic element and at least one locking engagement means for the locking engagement of the lid to the basic element. The locking means comprises at least one first element for locking to the basic element and at least one second locking element, which is integral with the lid and may be brought into directly locking engagement with the first locking element. It is provided that the generic drainage device is developed such that at least one projection, which protrudes in the direction of the base of the basic element and holds the second locking element, is substantially rigidly secured to, preferably integrally formed on, the lid. As a result of the specific position and configuration of the locking means, the cover grate may still be used even when substantial amounts of soil, sand or organic material have been deposited. The locking elements of the engagement means are integral parts of the lid or basic element; no further engagement elements, such as screws, clamps and the like, are therefore required for the locking process.

According to a preferred configuration of the invention, at least a portion of the projection that holds the second locking element and/or at least a portion of the basic element that holds the first locking element is resilient in its configuration, preferably in a direction at an angle to the plane of the lid. This allows the locking of the two locking elements to be assisted in a simple manner and facilitates the attachment of the lid to the basic element. Accordingly, in this configuration, the portions holding the first locking element and/or the second locking element may be swivelled in a resilient manner about a notional swivel axis, which preferably extends parallel to the plane of the lid or is located in said plane.

Moreover, it is preferred that the portions holding the first and/or second locking element each span a plane extending at an angle, preferably transversely, to the longitudinal extent of the basic element. Disengagement of the engagement means in the event of forces acting in the longitudinal direction on the lid of the drainage device is thus rendered more difficult or entirely prevented.

The lid preferably comprises ribs, in particular for the purpose of rigidification, the projection being formed by a rib or being arranged, preferably integrally formed, on a rib. In particular, the ribs are configured, at least in part, as transverse ribs extending between longitudinal sides of the lid, and the projection is located on these transverse ribs. In terms of production, the aforementioned embodiment of the engagement means may be provided in a particularly simple manner, so the overall manufacturing costs of the drainage device may be reduced.

In a preferred configuration of the invention, the first and second locking elements comprise complementary recesses and swellings. Said recesses and swellings may preferably be configured such that the first element for locking to the basic element has a ridge, and the second locking element a complementary groove. The configurations of the locking elements, which are in principle very simple to provide during production and are thus associated with low manufacturing costs, have proven highly robust with respect to environmental influences and mechanical loads. If the device should become soiled or sediments be deposited in the region of the locking elements, cleaning of the locking elements, for example by means of high-pressure water cleaning, is particularly simple, as all of the constituent parts of the locking means are easily accessible.

However, other constructional possibilities are also conceivable for bringing the first and second locking elements into mutual locking engagement. Thus, for example, the first and second locking elements may alternatively comprise locking noses that may be brought into mutual engagement. The locking noses of the first and second elements are usually aligned with each other and interlock in the locking position, and thus in the closed state of the engagement means.

It is also preferred that the basic element comprises at least one bearing surface for the lid, an indentation being formed in the region of the bearing surface and the first locking element being arranged within the indentation. If the basic element comprises a skirt, which serves to receive the lid, then the first locking element is preferably integrated into the skirt. The aforementioned measures allow displacement of the cover grate owing to mechanical loads in the longitudinal direction to be prevented. The assembly and repositioning of the cover grate on the basic element after maintenance is also facilitated, as the configuration of the locking elements assists the pre-positioning of the cover grate on the basic element. In the assembled state of the drainage device, the second locking element protrudes into the indentation in the basic element and is in locking engagement with the first locking element.

It is also preferred that the second locking element is arranged on the portion of the projection that is remote from the lid. The portion of the projection that is remote from the lid may expediently be wider than the remaining portion of the projection and preferably have the shape of a rod located substantially parallel to the plane of the lid.

In a further preferred configuration of the invention, a means is provided for displaceably arranging the lid on the basic element. A means of this type allows the lid to be fixed to the basic element such that it may not be displaced with respect to the basic element if forces are introduced into the lid, in the direction of the extent thereof, as a result of external influences. Such forces acting in the longitudinal and/or transverse direction occur primarily when vehicles drive over the lid. Particularly high forces of this type are produced during deceleration or acceleration, in particular. As a result of such forces, the lid tends to become displaced with respect to the basic element. The engagement means is thus subjected to increased loads, and there may be a risk of more rapid wear or even damage. The aforementioned means, on the other hand, provides a system for the prevention of accidental displacement in that it absorbs the forces introduced into the plane of the lid and thus relieves the engagement means.

A development of the aforementioned configuration is distinguished in that the means for displaceably arranging the lid comprises at least one pair of engagement means that may be brought into mutual engagement, of which the first engagement means is arranged on the lid and the second engagement means is arranged on the basic element. The first engagement means may comprise at least one nose and the second engagement means at least one recess for receiving at least one nose; however, an inverse configuration is also conceivable. If the basic element is provided with at least one bearing surface for the lid, the first engagement means may expediently be configured on the lower side of the lid, and the second engagement means on the bearing surface of the basic element. In a particularly preferred development, the nose rises from the bearing surface and the recess on the lower side of the lid forms a corresponding indentation, with which the nose engages in order to fix the lid to the basic element in a non-displaceable manner with respect to the bearing surface. If the lid comprises ribs, with the edge portions of which the lid rests on the bearing surface on the basic element, at least one recess may preferably be formed by the gap between two adjacent edge portions of the ribs.

Conventionally, the basic element comprises at least one side wall portion; in this case, the means for displaceably arranging the lid may, alternatively or additionally to the above-described configuration, comprise at least one stop for abutment with the side wall portion, in order to form a further displaceable locking means. Provided that the basic element comprises at least one bearing surface for the lid, below which the side wall portion is located, the stop may form an extension arranged on the lower side of the lid.

Finally, if the basic element comprises a skirt, which serves to receive the lid, the second engagement means is expediently configured on the skirt.

Further preferred configurations of the invention also emerge from the features recited in the sub-claims.

The invention will be described below in greater detail with reference to an embodiment and a plurality of drawings, in which:

FIG. 1 is a plan view of a drainage channel for surface drainage according to a first embodiment;

FIG. 2 is a sectional view, taken along the line II-II, through the drainage channel according to FIG. 1;

FIG. 3 is a sectional view, taken along the line III-III, through the drainage channel according to FIG. 1;

FIG. 4 is an enlarged detail of the drainage channel according to FIG. 1, in the region of the locking elements of an engagement means, along the line IV-IV;

FIG. 5 is a lateral, half-sectional view of a cover grate for a drainage channel according to a second embodiment;

FIG. 6 is a cross section through the cover grate according to FIG. 5;

FIG. 7 is a perspective bottom view of the cover grate according to FIG. 5; and

FIG. 8 is a view, perspective in certain regions, of a portion of a skirt of a basic element of the drainage channel according to FIG. 1.

FIG. 1 is a schematic plan view of a drainage channel 10 for surface drainage according to a first embodiment, such as is typically used in traffic surfaces. The drainage device 10 is composed of a cover grate 22 and a basic element 12. Of the basic element 12, the perspective view of FIG. 1 shows merely a frame 14 extending in the longitudinal direction of the drainage device 10. The upper sides of the cover grate 22 and the frame 14 form a plane, which serves as a traffic surface.

Details regarding the structure of the basic element 12 may be inferred from FIG. 2 and FIG. 3, which are lateral views along the lines II-II and III-III of FIG. 1. The basic element 12 comprises an elongate opening 16, which is located in the plane of the traffic surface, merges with the channel element 17 and is covered by the cover grate 22 in the assembled state of the drainage channel 10. Water infiltrating through the opening 16 is collected at the base 18 of the channel element 17 and discharged.

It is also apparent from FIGS. 2 and 3 that the basic element 12 according to the illustrated embodiment comprises a skirt 19 that is attached to the channel element 17. FIG. 8 shows an enlarged detail of the skirt 19. As may be seen from FIGS. 3 and 8, the skirt 19 forms, at its sides directed toward the inside of the basic element 12, a shoulder 20, which is in each case downwardly set apart from the plane of the traffic surface. This shoulder 20 comprises a planar, horizontally oriented upper side, which acts as a bearing surface 21 for the cover grate 22. For the purposes of sound absorption, a resilient plastics material insert 24, which protrudes from the upper side of the shoulder, is conventionally provided. The basic element 12 may, for example, be made of concrete and the skirt 19 of a corrosion-resistant metal or plastics material.

In the illustrated embodiment, the plane 15 of the traffic surface of the cover grate 22 is formed by an outer peripheral web 26, five longitudinal openings 27 and four parallel longitudinal webs 28 at a corresponding mutual distance from one another. The peripheral web 26 widens slightly at its two longitudinal ends and is located, in the assembled state of the drainage device 10, as may be seen in the cross section of FIG. 3, with its lower side on the bearing surface 21 of the elongate projections 20 or on the resilient plastics material inserts 24 thereof.

Below the peripheral and longitudinal webs 26, 28 forming the traffic surface of the cover grate 22, transverse ribs 32 extend between the longitudinal sides of the cover grate 22 (only partly visible in FIG. 1). The transverse ribs 32 are integrally connected to the further elements of the cover grate 22, i.e. in particular the peripheral and longitudinal webs 26; 28, and are used substantially for rigidifying the cover grate 22.

The cross section illustrated in FIG. 2, taken along the line II-II of FIG. 1, shows a relative position of the individual transverse ribs 32 in the cover grate 22. Two of the transverse ribs 32 shown in cross section in FIG. 2 are provided with lugs or projections 34, 36 which point toward the base 18 of the basic element 12 and on which engagement means 38,40 are arranged. Engagement means may, of course, also be provided on further transverse ribs 32.

FIG. 4 shows, by way of example, an enlarged detail of the drainage device 10 in the region of the engagement means 40, along the line IV-IV of FIG. 1. The engagement means 40 comprises a first element 42 for locking to the basic element 12 and a second element 44 for locking to the cover grate 22, which second element may be brought into directly locking engagement with the first locking element 42.

According to the illustrated first embodiment, the first locking element 42 is configured as a ridge extending transversely to the longitudinal extent of the basic element 12 and is located substantially in the centre of a side wall 50 of a downwardly directed U-shaped portion 50, which is provided on the inside of the skirt 19 and forms an indentation or a kind of bead in the shoulder 20. The side wall 50 holding the first locking element 42 spans a plane extending transversely to the longitudinal extent of the basic element 12.

According to the illustrated first embodiment, the second locking element 44 is configured as a groove that extends transversely to the longitudinal extent of the basic element 12 and is complementary to the ridge of the first locking element 42; the second locking element 44 is arranged on a side wall 56 of the projection 36 of the transverse rib 32. The projection (36) holding the second locking element 44 spans a plane extending transversely to the longitudinal extent of the basic element 12. Accordingly, in the illustrated first embodiment, the second locking element 44 is integrally connected to the cover grate 22. The second locking element 44, which is provided as a groove, is provided at both lateral ends 54a of a lower end portion 54 of the projection 36. As may be seen from FIG. 3, the two lateral ends 54a of the lower end portion 54 extend substantially over the entire width of the lid 22, while the remaining projection 36 is less wide.

In the case of the engagement means 38, 40 of FIG. 2, the individual locking elements 42, 40 are respectively arranged on side walls, which face away from one another, of the projections 34, 36, which hold said locking elements and are integrally formed on a transverse rib 32. Although the projections 34, 36 are substantially rigidly integrally formed, via the respective transverse rib 32, on the cover grate 22, they nonetheless possess a certain resilience, so they are subjected to a slight tension once the cover grate 22 has been locked, thus providing the necessary holding force for the engagement means 38, 40 and hence completing the locking process.

For assembly, the cover grate is placed onto the basic element 12, the engagement means 38, 40 facilitating precise positioning. Once the cover grate 22 has been placed, it is pressed perpendicularly downward, the first locking elements 42, which are configured as ridges, sliding via the side walls 56 of the transverse ribs 32 until they engage with the groove-like second locking elements 44. In order to facilitate assembly and to achieve the locking effect, the projection 36, which holds the second locking element 44, of the associated transverse rib 32 and/or the side wall 50, which holds the first locking element 42, of the U-shaped portion 52, which forms an indentation, of the skirt 19 are configured so as to yield in a resilient manner in a direction at an angle to the plane 15 of the cover grate 22.

In the illustrated embodiment, as may also be seen from FIG. 2, the two engagement means 38, 40 are configured mirror-symmetrically to each other in that the first locking elements 42, which are configured as a ridge, face one another and the second locking elements 44, which are configured as a groove, face away from one another. As a result, during the locking of the lid 22 to the skirt 19 of the basic element 12, the transverse ribs 32, which are provided with the second locking element 44, are subjected to a tilting movement toward one another; this, in turn, produces a torque acting in the opposing direction in order to achieve engagement of the second locking element 44 with the first locking element 42. In this way, one of the engagement means 38, 40 forms in each case a counter-bearing with respect to the other engagement means.

However, the engagement means 38, 40 may also, of course, be configured mirror-symmetrically to each other in the inverse effective direction. Finally, however, it is, in principle, conceivable to provide only one engagement means in the above-described manner and optionally to configure a stop, which is arranged at a distance from said engagement means and acts as a counter-bearing.

In addition to the illustrated configurations of the locking elements 42 and 44, means for locking the cover grate 22 to the basic element 12 that comprise complementary recesses and swellings on the transverse ribs 32 or on the basic element 12 may also be provided. A plurality of locking elements of this type may also be arranged on a transverse rib 32 and accordingly in the region of the basic element 12. In the case of the arrangement illustrated according to FIG. 4, for example, the left-hand side wall, seen from the viewer's perspective, of the transverse rib 32 or the indentation 52 may in each case hold a locking element. The arrangement of the locking elements in the region of walls located perpendicularly to the traffic surface has proven particularly beneficial, because the depositing of sediments in the region of the engagement means 38, 40 may thereby be markedly reduced.

FIGS. 5 to 7 show a cover grate 122 of a second embodiment of a drainage channel. This cover grate 122 is suitable for placement on a basic element, as described above with reference to FIGS. 1 to 4. The basic element 12 according to the first embodiment may therefore also be used for the second embodiment, which will be described below, without any fundamental alterations. The upper side of the cover grate 122 is configured in an identical or similar manner to that shown in FIG. 1 with reference to the cover grate 22 of the first embodiment. FIG. 5 shows the cover grate 122 with a left-hand partial longitudinal section along a line corresponding to the line II-II of FIG. 1, and FIG. 6 shows a cross section through the cover grate 122 along a line corresponding to the line III-III of FIG. 1.

This cover grate 122 differs from the cover grate 22 according to the first embodiment in that the transverse ribs 132 extend over the entire width of the cover grate 122, and the cover grate 122 rests on the bearing surface 21 of the basic element 12 only with the lateral end portions 132a of the transverse ribs 132. When the cover grate 122 abuts the bearing surface 21 of the basic element 12, gaps, where the cover grate 122 does not rest on the bearing surface 21 of the basic element 12, are thus formed between the end portions 132a of each pair of adjacent transverse ribs 132.

The lid 122 also differs from the first configuration in that the engagement means 138, 140 are configured differently. Although the locking means 138, 140 also have a locking function, in the case of the second configuration, the second locking elements 144 are configured as wedge-shaped locking projections. In the closed state, the second locking elements 144, which are configured as wedge-shaped projections, underlap the first locking elements, which are configured on the basic element 12, are arranged in an identical or similar manner to the first locking elements 42 in the first configuration, and are also configured in a similar manner as ridges or projections.

In the second configuration, similarly to as in the first configuration, the second locking element 144 is also located on a lower end portion 154 of the projection 134 or 136. However, in the second configuration, unlike in the first configuration, the second locking element is configured as a rod, which extends parallel to the plane of the cover grate 122 over the entire width of the cover grate 122, whereas the projection 134 or 136 holding the second locking element 144 is significantly less wide, as may be seen, in particular, from FIGS. 6 and 7.

In all other respects, the construction of the second embodiment substantially corresponds to that of the first embodiment, so further description is not required at this point.

Alternatively, however, it is also conceivable to arrange, for example by casting, a high-grade steel spring, which is biased on the basic element in the direction toward the first locking element and may be brought into engagement with said basic element, for example on the lower side of the cover grate or on the corresponding transverse rib.

As may also be seen from FIGS. 2 and 8, recesses 60 and 160, with which noses 62 correspondingly arranged on the basic element 12 engage, are formed on the lower side of the lid 22 or 122.

In FIG. 2, with respect to the first embodiment, the recesses 60 and the associated noses 62 are illustrated by broken lines, whereas in FIG. 5 only the noses 62 may be seen in perspective. In the first embodiment, two noses 62, which are set apart from each other, are arranged on the bearing surface 21 of the shoulder 20, which is configured on the skirt 19, so the noses 62 rise form the bearing surface 21 (cf., in particular, FIG. 5). Accordingly, in the illustrated embodiment, the associated recesses 60 are formed on the lower side of the peripheral web 26 of the lid 22. However, it is also conceivable to provide only one nose 62 on the basic element 12 and accordingly a recess 60 on the lid 22. It is also conceivable to provide more than two pairs of recesses 60 and noses 62. Conventionally, at least one nose 62, which engages with an associated recess 60 formed on the corresponding longitudinal side of the lid 22, is arranged on each longitudinal side of the basic element 12.

In the case of the second embodiment, on both longitudinal sides of the cover grate 122, the two recesses are each formed by a gap produced, when the lid 122 is placed onto the basic element 12, between a lateral end portion 133, which widens in the longitudinal direction of the cover grate 122, of a central transverse rib 132 and the lateral end portion 132a of the adjacent transverse ribs 132. The noses 62, which rise from the bearing surface 21 of the basic element 12, engage with these gaps, which act as a recess 160 (cf. FIG. 5). In the illustrated embodiment, the dimensions of the width of the widening lateral end portion 133, in the longitudinal direction of the cover grate 122, are such that said end portion substantially fits in the gaps formed between the two noses 62, which are arranged in a pair, so both noses 62 substantially abut this widening lateral end portion 133 in order to bring about a locking process with as little tolerance as possible, in order to achieve the desired displacement prevention. However, alternatively or additionally, it is also conceivable for the dimensions of the width of the recesses 160, in the longitudinal direction of the cover grate 122, to correspond to the width of the noses 62 engaging with said recesses.

Thus, when the lid 22 or 122 is placed onto the basic element 12, not only do the first and second locking elements engage for the locking engagement of the lid 22 or 122 to the basic element 12; the noses 62 on the basic element 12 also engage with the recesses 60 or 160 on the lower side of the lid 22 or 122. The arrangement consisting of a recess 60 or 160 and an associated nose 62 accordingly provides a displacement prevention means, which fixes the lid 22 or 122 with respect to the basic element 12 in order to prevent undesirable movements in the longitudinal direction. Such undesirable displacement may occur, in particular, when vehicles drive over the lid 22 or 122, thus resulting in increased loading of the locking means 38, 40 or 138, 140. The displacement prevention means formed by the noses 62 and the associated recesses 60 or 160, on the other hand, allows the engagement means 38, 40 or 138, 140 to be correspondingly relieved.

The above-described arrangement of recesses 60 or 160 and noses 62 serves substantially for non-displaceably locking the cover grate 22 or 122 in the longitudinal direction.

For non-displaceable locking in the transverse direction, further measures may, if required, be provided. In the case of the cover grate 122 according to the second embodiment, such measures are provided in the form of extensions 164. As may be seen from FIG. 7, these extensions 164 are formed integrally on transverse ribs 132 and extend downward. However, alternatively, it is also conceivable to arrange the extensions, for example, at a different location on the lower side of the cover grate. The extensions 164 are positioned such that they form a stop for abutment with the respective adjacent inner side wall portion 19a of the skirt 19 of the basic element 12, which is connected to said skirt below the bearing surface 21 (cf. FIGS. 3 and 8). However, it is also conceivable that the length of the extensions acting as a stop is such that said projections may be brought into abutment not only with the inner side wall portion 19a of the skirt 19, but also with the inner side wall portion 17a of the channel element 17 connected therebelow.