Abstract:
The invention relates to a fixing device for a cover of a drainage channel, road or yard gully or similar surface drainage devices, said cover being placed on an upper rim of a channel body, runoff box or similar body that can be embedded in the ground, with first fixing elements on the cover and second fixing elements on the body embeddable in the ground, such that the first fixing elements and the second fixing elements in each case can be brought into snapping engagement with one another to retain the cover on the body. The fixing device achieves a secure locking of the cover by simple manipulation, while simultaneously optimizing the cover&#39;s seating. To accomplish this the first fixing elements and/or the second fixing elements each comprise at least one damping section with a contact surface between the cover and the body embeddable in the ground, so that when locked in position the cover is spaced apart from the upper rim of the body.

Description:
RELATED U.S. APPLICATIONS  
       [0001]     Not applicable.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable.  
       REFERENCE TO MICROFICHE APPENDIX  
       [0003]     Not applicable.  
       FIELD OF THE INVENTION  
       [0004]     The present invention relates to a fixing device for a cover of a drainage channel, road or yard gully or similar surface drainage devices, said cover being placed on an upper rim of a channel body, runoff box or similar structure that can be embedded in the ground.  
       BACKGROUND OF THE INVENTION  
       [0005]     For industrial purposes as well as in the public or private sectors surface drainage devices are employed to carry away rain or muddy water, water that has been used for cleaning, or environmentally hazardous liquids. When used to drain roadways, parking lots or pedestrian zones, for example, such devices must be able to withstand high static and dynamic loads. A crucial factor here is that the cover be seated and fixed on the body that can be embedded in the ground, so as to ensure in particular the stability of the surface drainage device, especially its cover, when exposed to traffic.  
         [0006]     The general set of problems encountered with fixing devices for this purpose resides primarily, for instance in the presence of dynamic loads caused when vehicles drive over the cover at high speed, on one hand in the fact that the cover must be kept in its position on the body embedded in the ground while at the same time uncoordinated evasive movements of the cover, resulting in danger to traffic or undesirable noise, ought to be avoided. On the other hand the cover should be held in place in such a way that it can easily be removed and inserted again, so that any necessary maintenance and cleaning work can be performed rapidly and simply. It must also be ensured that the high pressure that pushes the cover against the underlying structure does not cause fatigue of the material in the surface drainage device.  
         [0007]     The document DE 195 45 131 A1 discloses fixing devices for a cover such that at each device a fastener bolt at the cover engages a fastener element associated with the channel body. After it has been locked in position, the cover lies on an upper rim of the channel body. The locking and removal of the cover in this case is extremely laborious, because each fastener bolt must be individually screwed to the channel body or released therefrom. In addition, in particular impulse-like loads applied to the cover are absorbed exclusively by the cover and channel body, which at least in certain regions of the surface drainage device can easily cause material fatigue.  
         [0008]     From DE 202 00 509 a device for locking a covering grate to drainage channels in known, in which the cover rests on an upper rim of the channel body when locked in position. The fixing device disclosed there permits rapid locking of the cover to the channel body, but requires an extremely complex arrangement. Here again, as mentioned above, impulse-like loads applied to the cover must be absorbed exclusively by the cover and channel body. Hence the surface drainage device undergoes excessive stress, so that material fatigue results.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     It is an object of the invention to provide a fixing device for a cover placed on an upper rim of a channel body, runoff box or similar structure that can be embedded in the ground, as part of a drainage channel, road or yard gully or similar surface drainage devices, that is developed further than the prior art in such a way that a secure locking of the cover is obtained by simple manipulation, while at the same time the cover is optimally seated.  
         [0010]     According to the present invention there is provided a fixing device for a cover of a surface drainage devices, comprising said cover and a body adapted to be embedded in the ground and defining an upper rim on which said cover can be placed; first fixing elements provided on said cover and second fixing elements provided on said body that can be brought into snapping engagement with one another to lock said cover to said body; and at least one of said first fixing elements and said second fixing elements comprising at least one damping section defining a contact surface between said cover and said body such that when said cover is locked to said body said cover is spaced apart from said upper rim of said body.  
         [0011]     In particular, the aforementioned problem is solved or substantially mitigated by a fixing device as above.  
         [0012]     The efficacy of the invention resides in the fact that the fixing elements serve simultaneously as damping elements between the cover and the body embeddable in the ground, the damping elements being disposed at the upper rim of the body embeddable in the ground and/or at the cover in order to avoid direct contact between the upper rim and the cover. Kinetic energy introduced into the surface drainage device by a dynamic load is converted by the drainage device into potential energy and, when the movement direction is reversed, is released again as kinetic energy. A damping material installed in the surface drainage device absorbs additional energy, so that the amount of energy released by the device is considerably less than the amount introduced. As a result, impulse-like impacts and resulting uncoordinated movements of the cover are alleviated, because the movement velocity of the cover is reduced as intended. Furthermore, clattering noises are damped. And in addition, both owing to the damping material and also because evasive movements of the cover are possible, when the cover is pressed strongly against the upper rim of the body this pressure is compensated, so that material fatigue in the surface drainage device is prevented.  
         [0013]     Preferred further developments of the invention are described in the subordinate claims.  
         [0014]     For instance, in one preferred embodiment the damping section is constructed so as to be elevated with respect to the level of the upper rim of the body, at each of the second fixing elements that serve to lock the cover by way of its first fixing elements, such that the elevation extends in a direction perpendicular to the long direction of the upper rim. The advantage here is the simple construction and hence an economical manufacture of the fixing elements integrated into the body. The fixing elements are merely set at a particular height by lengthening them in a direction perpendicular to the long direction of the upper rim, and thus in the simplest possible manner serve the purpose of optimizing the seating of the cover while simultaneously facilitating its locking.  
         [0015]     In another preferred embodiment the damping section is constructed as an integral component of the first fixing element, which protrudes beyond the level of the surface of the cover that faces a body embeddable in the ground. In this case the first element divides the protrusion, so that ultimately two protrusions are formed at the first element. Then the protrusions extend in the long direction of the body embeddable in the ground, such that they are apposed at least to the second fixing element. The protrusion associated with the first fixing element can advantageously be lengthened as desired in the long direction of the body, so that it extends beyond the second fixing element to contact the upper rim or frame of the body. This is advantageous when a high damping action is to be obtained in case of heavy loading of the surface drainage device.  
         [0016]     Alternatively it is possible to attach the damping sections to both the first and the second fixing element. The advantage here is that in addition to their damping action they cooperate with one another, so that they are exposed to less wear and tear.  
         [0017]     The protrusion can preferably be elevated 1 to 2 mm above the upper rim of the body and/or above the surface of the cover that faces the body. As a result, the seating of the cover is optimized with the smallest possible consumption of material and hence with low manufacturing costs.  
         [0018]     The first and/or the second fixing elements are in each case made of elastic material, such as spring steel or an elastomer. Thus in the simplest manner impacts and oscillations are absorbed, and disturbing clatter noises caused when vehicles drive over the cover are damped.  
         [0019]     In another advantageous embodiment the first and second fixing elements are each disposed in the body embeddable in the ground or on the cover so that they cannot be lost, i.e. are captive. For example, the second fixing elements are cast into the body or glued thereto. This ensures an extremely economical means of attaching the elements.  
         [0020]     However, it is also possible to install in particular the second fixing element in the body in such a way that although captive, it can nevertheless be exchanged, e.g. in case it becomes worn. Preferably for this purpose both the prefabricated channel body and also the frame comprise apertures that are accessible from an interior of the channel and into which the fixing element can be inserted. To guarantee secure retention of the fixing element, primarily during removal of the cover, the element can advantageously be constructed with projections that extend outward from the side of the element and hence in the long direction of the channel body, being situated opposite one another and pointing in opposite directions. These projections are preferably disposed such that they are distinctly spaced apart from the upper rim when the fixing element has been inserted. If in particular the aperture in the channel body corresponds substantially to the shape of the fixing element, then the projections are covered by the overlying channel material in such a way that during removal of the cover, with the associated vertical pulling forces, the element cannot be dragged along and remains in the body. A captive installation of the fixing element also ensures secure locking of the cover to the body, because in addition to the vertical pulling forces, horizontal displacing forces can be absorbed by the fixing elements engaged with one another. Furthermore, the elements cannot be lost during installation or repair and maintenance work on the surface drainage device.  
         [0021]     Preferably the first and second fixing elements are designed to be complementary to one another. To this end, for example, the second fixing elements have the shape of a parallelepiped and accordingly each has two side walls opposite one another, a front wall, a back wall opposite the front wall, an upper wall and a lower wall opposite the upper wall. The front wall of the second fixing element extends parallel to the long direction of the body embeddable in the ground and faces toward the middle of the channel body. The side walls are thus perpendicular to the long direction of the body embeddable in the ground. To receive the first fixing element each of the fixing-element parallelepipeds incorporates a cavity that is accessible from at least one of its sides. By way of an opening on the upper wall of the second fixing element, the first fixing element comes into engagement with the cavity. For this purpose the first fixing element is, for example, shaped like a peg. Ideally the first and the second fixing elements then engage one another in such a way that the first fixing elements are protected while housed within the second fixing elements.  
         [0022]     The solution in accordance with the invention provides that the first peg-shaped fixing elements and the second fixing elements, which enclose a cavity, each comprise at least one lug-like projection. The first fixing elements in each case can then be brought into engagement by way of these projections, in particular can be snapped together, because the first and/or the second elements in each case are made of flexible material. Preferably the first and the second fixing elements are made of materials differing in hardness. The at least one lug-like projection of the first fixing element must overcome the at least one lug-like projection of the second fixing element, so that the first fixing element is subsequently held in the cavity within the second element. As a result of the fact that the at least one projection of the second fixing element then overlies the at least one projection of the first fixing element, the first fixing element and hence the cover is held in its locked position. This requires that the at least one lug-like projection of at least one fixing element, or the entire fixing element, be flexibly deformable and hence be made of an elastic material, for example spring steel or an elastomer. The hardness of the material, however, must be specified such that the vertical forces acting to pull the cover out are counteracted by the higher stiffness of one fixing element in comparison to the additional fixing element engaged therewith.  
         [0023]     An especially simple and economical embodiment for the second fixing elements can be obtained by projections in the shape of rods. The rods projecting into the cavity of the fixing device are preferably made rigid and can be brought into snapping engagement with first fixing elements that are flexible and that, for example, each comprise recesses to receive the rods when the cover is locked in place.  
         [0024]     In one advantageous embodiment a first lug-like projection is disposed within the second fixing element in each case, to form a clamp together with a second lug-like projection disposed opposite thereto. This design enables a particularly secure and nevertheless simple locking of the cover by way of the latter&#39;s first fixing element, because the clamp to a great extent encloses the engaged fixing element.  
         [0025]     Alternatively there is provided within one fixing element only a single lug-like projection to engage the complementary fixing element and, for example, in another body wall opposite this wall of the body a fixing element is formed with a lug-like projection oriented in the opposite direction. Hence a locking mechanism would be embodied that saves material, is economical and is adequately secure in particular for a surface drainage device designed for relatively slight imposition of force. This embodiment is particularly simple and economical to manufacture.  
         [0026]     Advantageously the at least one lug-like projection within the associated fixing element extends parallel to the long direction of the body embeddable in the ground, i.e. along the back wall of the fixing element. Hence an entire length of the associated fixing elements in the long direction of the body embeddable in the ground can be used to form the lug-like projection, and/or the fixing elements can be made arbitrarily long so that in particular high forces acting on the surface drainage device can be absorbed while keeping the cover locked.  
         [0027]     Alternatively the at least one lug-like projection extends perpendicular to the long direction of the body embeddable in the ground, i.e. along one of the side walls of the fixing element. This likewise enables a secure, space-saving and simple locking of the cover onto the body embeddable in the ground.  
         [0028]     In another preferred embodiment the first fixing elements are made flat in each case. This enables simple manufacture of the fixing elements and ensures an optimal snapping engagement in the complementary fixing elements.  
         [0029]     Furthermore, as one of the preferred embodiments it is provided that the damping section is constructed as an integral component of the first fixing element, a height of the first fixing element perpendicular to the long direction of the body embeddable in the ground being dimensioned such that the first fixing element is in contact with a floor of the cavity in the second fixing element, and a space separating the locked cover from the upper rim of the body embeddable in the ground can be produced. Advantageously, this construction is easy to implement, and a fixing element with the desired height can be manufactured simply and economically.  
         [0030]     It is advantageous for the second fixing elements each to be situated in opposite side walls of the body, preferably directly opposite one another. This ensures easy locking of the cover, and the fixing elements are accommodated in a space-saving manner, so that a free channel cross section is available. In addition, the fixing elements are hardly accessible to external influences, which is especially important when the cover is not locked in position, because they are protected within the side walls of the body.  
         [0031]     Alternatively it is possible for the second fixing elements to be disposed in opposite side walls of the body but offset from one another. A clatter-free retention of the cover on the body embedded in the ground is ensured in particular by this offset arrangement of the fixing elements.  
         [0032]     For another device in a preferred embodiment it is provided that the second fixing elements each comprise at least one opening towards a middle of the body, so that if dirt should enter the fixing elements it can be ejected, in particular when the first fixing elements are being inserted into the body. This ensures that no contaminants can become stuck within the fixing elements and thus make locking of the cover difficult. The work of cleaning is thereby facilitated, because any dirt that is present can be rinsed out directly and washed to the middle of the body.  
         [0033]     In the following, exemplary embodiments of the invention are described in greater detail with reference to the accompanying drawings. [0073] At this juncture it should be pointed out that all of the parts described above, in particular the details presented in the drawings, are claimed as essential to the invention, individually or in any combination. Modifications thereof are familiar to a person skilled in the art. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0034]      FIG. 1  is a schematic drawing in perspective of a second fixing element installed in a channel body and a corresponding first fixing element, in a first embodiment;  
         [0035]      FIG. 2  shows a schematic front view of the first and the second fixing elements in  FIG. 1 , wherein the first fixing element has been set onto the second fixing element;  
         [0036]      FIG. 3  shows a schematic front view of the first and the second fixing elements in  FIG. 1 , wherein the elements are engaged with one another;  
         [0037]      FIG. 4  is a schematic drawing in perspective of a second fixing element installed in a channel body and a corresponding first fixing element, in a second embodiment;  
         [0038]      FIG. 5  is a schematic drawing in perspective of a second fixing element installed in a channel body, in a third embodiment;  
         [0039]      FIG. 6  shows a schematic front view of a first and a second fixing element in a fourth embodiment;  
         [0040]      FIG. 7  shows a schematic front view of a first and a second fixing element in a fifth embodiment and  
         [0041]      FIG. 8  is a schematic drawing in perspective of a second fixing element installed in a channel body and a corresponding first fixing element, in a sixth embodiment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0042]     In the following description, the same reference numerals are used for identical parts or parts with identical actions.  
         [0043]     The perspective drawings in  FIG. 1  show a second fixing element  20   a  and a first fixing element  10   a , which corresponds to the second element  20   a  and can be received therein; said first fixing element is disposed on a cover  7  that can be set onto an upper rim  6  of a body  2  embeddable in the ground. The fixing element  20   a  is fastened within a wall  3  of a channel body  2 . It is advantageous that the element  20   a  is thereby protected and disposed in a space-saving manner, so that a free channel cross section is available for the materials that are to be guided away in the surface drainage device.  
         [0044]     The second fixing element  20   a  has the overall shape of a parallelepiped and accordingly comprises two side walls  30 ,  30 ′ disposed opposite one another, a front wall  28 , a back wall  29  opposite the front wall  28 , an upper wall  31  and a lower wall opposite the upper wall  31 . The front wall  28  extends parallel to the long direction of the body  2  embeddable in the ground and faces toward a middle of the channel body  2 . The side walls  30 ,  30 ′ extend in a direction transverse to the long direction of the body  2  embeddable in the ground. The side walls  30 ,  30 ′, the front wall  28  and back wall  29 , the upper wall  31  and the lower wall define a cavity  23 . By way of a first opening  25  in the upper wall  31  of the second fixing element  20   a , the first fixing element  10   a  can be set into the cavity  23 .  
         [0045]     The second fixing element  20   a  is preferably cast into the channel body  2 . Accordingly, an edge-protecting frame  5  that covers the upper rim  6  comprises openings to make the element  20   a  accessible. The fixing element  20   a  is disposed within the channel body  2  in such a way that it protrudes above the upper rim  6 , preferably by ca. 2 mm. Hence the fixing element  20   a  comprises a protrusion  27 ,  27 ′ above the level of the upper rim  6 . Consequently a cover  7  set onto it does not lie directly on the upper rim  6  of the channel body  2 , or on the frame  5 , but rather on a bearing surface that extends parallel to the upper rim  6  and is formed by the protrusion  27 ,  27 ′, which serves as contact surface  11 ,  11 ′ between the cover  7  and the body  2  embeddable in the ground, and is therefore spaced apart from the upper rim  6 . The second fixing element  20   a  is preferably made of an elastic material, for example spring steel or an elastomer, so that the protrusion  27 ,  27 ′ acts as a damping section  26 ,  26 ′ and the cover  7  is seated so as to be damped. Hence impacts applied to the surface drainage device from outside are attenuated and disturbing clattering noises of the cover  7  are avoided.  
         [0046]     The second fixing element  20   a  comprises two lug-like projections  22 ,  22 ′ situated opposite and spaced apart from one another, which within the cavity  23  extend perpendicular to the long direction of the body  2  embeddable in the ground, i.e. they run along the side walls  30 ,  30 ′ of the second fixing element. The projections  22 ,  22 ′ in this exemplary embodiment are in part an integral component of the protrusion  27 ,  27 ′ and extend perpendicular to the long direction of the body  2  embeddable in the ground, i.e. they are situated on the side walls  30 ,  30 ′ of the fixing element  20   a.    
         [0047]     A second opening  24  is formed in the front wall  28  of the second fixing element  20   a , in such a way that the cavity  23  is open toward the middle of the channel body  2 . Accordingly, any dirt or the like that is present in the fixing element  20   a  can be shifted directly into the channel body  2 .  
         [0048]     The first opening  25  and the second opening  24  of the fixing element  20   a  in this embodiment are joined to one another. The back wall  29  of the fixing element  20   a  comprises a third opening  24 ′ that is joined to the first opening  25  and second opening  24 , so that the fixing element  20   a  has substantially a U-shaped configuration, forming a clamp within which to receive the first fixing element  10   a . Accordingly, the protrusion  27 ,  27 ′ comprises two contact surfaces  21 ,  21 ′ that are separated from one another. The lug-like projections  22 ,  22 ′ are adjacent to the contact surfaces  21 ,  21 ′ in the direction toward the cavity  23 , and each of them is tapered toward the cavity  23  to ensure that the first fixing element  10   a  will click into place, on account of the greater flexibility of the tapered projections  22 ,  22 ′ in comparison to the remaining region of the second fixing element  20   a.    
         [0049]     Because of the relatively simple configuration of the U-shaped fixing element  20   a , locking of the cover  7  can be implemented economically while the associated manipulation is simple and efficient.  
         [0050]     Because a width B 20a  of the fixing element  20   a  transverse to the long direction of the channel body  2  in this case corresponds substantially to a width B 4  of the upper rim  6  of the body  2 , in the direction transverse to its long direction, the third opening  24 ′ of the fixing element  20   a  in this exemplary embodiment is closed by the frame  5 , which has been cast into the body  2  and passes over an outer surface of the wall  3  of the body  2 . The fixing element  20   a  is thus advantageously protected at its back from the entrance of soil. The front wall  28  of the fixing element  20   a  is flush with an inner surface of the wall  3  of the channel body  2 . Accordingly, this wall of the channel  2  together with the fixing element  20   a  forms a planar surface next to a channel interior, so that no dirt can adhere to it.  
         [0051]     Alternatively, the width B 20a  of the fixing element  20   a  transverse to the long direction of the channel body  2  can be smaller than the width B 4  of the upper rim  6  of the body  2  transverse to its long direction. The fixing element  20   a  would then be surrounded by the channel material at its back wall  29 , so that the frame  5  can be eliminated in this region. It would in addition be possible to surround the fixing element  20   a  with channel material at its front wall as well. The element  20   a  would then be enclosed in the channel wall  3  and completely protected. It would then be advantageous for the channel wall  3  to comprise an opening, to enable any pollutants to be rinsed out of the fixing element  20   a.    
         [0052]     The first fixing element  10   a  on the cover  7  is constructed so as to correspond to this embodiment of the second fixing element  20   a . The fixing element  10   a  is shaped like a broad, flat peg and likewise comprises lug-like projections  12 ,  12 ′, so that it can be inserted into the cavity  23  within the second fixing element  20   a.    
         [0053]     Because the width B 20a  of the fixing element  20   a  and a width B 22  of the projections  22 ,  22 ′ correspond substantially to the width B 4  of the upper rim  6 , a width B 10a  of the first fixing element  10   a  likewise corresponds substantially to the width B 4  of the upper rim  6 .  
         [0054]      FIG. 2  shows a schematic front view of the first fixing element  10   a  as it acts on the second fixing element  20   a . At this stage the first fixing element  10   a  is seated on the second fixing element  20   a  without being engaged with the element  20   a . When a force F applied in the direction indicated by the arrow is transferred from the two lug-like projections  12 ,  12 ′ of the first fixing element  10   a  to the lug-like projections  22 ,  22 ′ of the second fixing element  20   a , i.e. toward a floor of the cavity  23 , the projections  22 ,  22 ′ become elastically deformed, so that they are overcome by the projections  12 ,  12 ′. The projections  22 ,  22 ′ are accordingly made of elastic material, for example spring steel or an elastomer. As a result it is possible for the first fixing element  10   a  to be enclosed completely within the cavity  23  of the second fixing element  20   a , so that the cover is locked in place by means of the fixing elements  10   a ,  20   a  (see  FIG. 3 ).  
         [0055]     If the first fixing element  10   a  is formed rigidly on a cast cover, for example, it is preferably cast along with the cover during the manufacturing process. Alternatively, it is possible to make the first fixing element  10   a  elastic as well. The element  10   a  is then attached to the cover  7  in a subsequent process. However, the hardness of the material should be specified such that the vertical pulling forces acting on the cover  7  are counteracted because of the greater stiffness of a fixing element in comparison with the other fixing element with which it is engaged.  
         [0056]      FIG. 3  shows a schematic front view of the complementary fixing elements  10   a ,  20   a  when they are engaged with one another. Because the projections  12 ,  12 ′ of the first fixing element  10   a  in the locked position are covered by the projections  22 ,  22 ′ of the second fixing element  20   a , the first fixing element  10   a  and hence the cover  7  are retained in their locked position.  
         [0057]      FIG. 4  shows a first fixing element  10   b  and a second fixing element  20   b , each in an embodiment different from but similar to the previous one. The fixing element  20   b  differs from the fixing element  20   a  in that the openings  24 ,  25  are separated from one another, so that the contact surface  21  formed by the protrusion  27  is designed as a continuous region.  
         [0058]     This arrangement enlarges the contact surface  21  and enables a first fixing element  10   b  that may be caught in the second fixing element  20   b  to be securely retained and guided therein. This is advantageous in particular when the surface drainage device is exposed to extremely high loads. So that any pollution that may be present can nevertheless be washed away into the channel body  2 , the opening  24  is provided for that purpose in a front wall  28  of the fixing element  20   b , which is oriented toward the middle of the channel.  
         [0059]     The fixing element  10   b  disposed on the cover  7  corresponds substantially to the element  10   a  in  FIG. 1 . However, the element  10   b  has a width Blob that is less than the width B 10a  of the element  10   a . That is, construction of the contact surface  21  as a continuous region requires that the projections be shortened, so that the fixing element  10   b  is adapted thereto.  
         [0060]     The embodiment according to  FIG. 5  has a second fixing element  20   c  similar to those previously described. The projection  22  provided for locking, however, in this case runs parallel to the long direction of the body  2  embeddable in the ground; that is, it is attached to the back wall  29  of the fixing element  20   c . This has the particular advantage that an entire length L of the cavity  23  in the long direction of the body  2  can be used to form the lug-like projection  22 , and/or the fixing elements  20   c  can be made arbitrarily long so that in particular high forces acting on the surface drainage device can be absorbed while keeping the cover  7  locked in place.  
         [0061]     FIGS.  1  to  4  show fixing elements  20   a ,  20   b  that each have two projections  22 ,  22 ′ disposed opposite one another. Alternatively, it would be possible to dispose only one projection  22  within each second fixing element (cf.  FIG. 5 ) and, for example, provide an oppositely oriented projection  22  as part of the second fixing element disposed in another wall of the channel body  2  situated opposite the channel wall  3 . This would implement a material-saving, economical locking mechanism that is in particular adequately secure for a surface drainage device designed to withstand relatively low forces. If the first fixing element nevertheless comprises two projections, one of these projections will extend into empty space, but the grate can be set onto the channel independently of the first fixing elements. To save material in construction of the first fixing elements, these are likewise made with only one projection, which comes into engagement with the associated projection of the second fixing element in each case.  
         [0062]     The apparatus shown in  FIG. 5  ultimately enables only one projection  22  to be formed in each fixing element  20   c  and requires the presence of a complementary bearing in the channel wall of the body  2  that is opposite the channel wall  3 . If a front wall  28  is explicitly formed in the parallelepiped constituting the fixing element  20   c , as in the embodiment according to  FIG. 4 , i.e. if the entrance opening  25  for the complementary fixing element  10   c  and the opening  24  for emergence of contaminants from the fixing element  20   c  were separate from one another, it would be possible to provide a second projection  22  here as well. The projections  22 ,  22 ′ could then be made long and narrow and hence be able to support high forces.  
         [0063]     A possible first fixing element (not shown here) that corresponds to the second fixing element  20   c , in the case of the projection/projections  22 ,  22 ′ fixed to the back wall  29  and/or to the front wall  28 , would have to be fixed to the corresponding cover  7  so as to be rotated by 90° in comparison to the fixing elements  10   a ,  10   b.    
         [0064]      FIG. 6  is a front view of fixing elements  10   d ,  20   d  that are engaged with one another. The second fixing element  20   d  is substantially similar to that shown in FIGS.  1  to  3 , but in this embodiment it is flush with the frame  5  that covers the upper rim  6 . So that the fixing element  20   d  can be accommodated in the wall  3  of the body  2 , both the frame  5  and the channel body  2  comprise openings, so that the fixing element  20   d  can be inserted into the channel body  2  and when appropriate removed again. The opening in the channel body  2  in this exemplary embodiment is therefore constructed so as to substantially reproduce the shape of the fixing element  20   d  and, e.g., comprises grooves  4 ,  4 ′.  
         [0065]     The element  20   d  comprises projections  32 ,  32 ′ disposed opposite one another and extending out of the side walls  30 ,  30 ′ in opposite directions along the long direction of the channel body  2 . Because the openings are accessible from the middle of the channel, the element  20   d  can preferably be pushed into them from that direction. Preferably the projections are disposed such that they are distinctly spaced apart from the upper rim when the fixing element has been inserted. Because in particular the opening in the channel body corresponds substantially to the shape of the fixing element, and the projections engage the grooves  4 ,  4 ′, the projections are retained by the overlying channel material so that when the cover is removed, with the associated vertical pulling forces, the element is not pulled along with it but remains in the channel body.  
         [0066]     Alternatively it is possible to cast the fixing elements together with the channel body, or to provide the prefabricated channel body with recesses within which the element is attached by adhesive. Each of these possibilities ensures a secure locking of the cover. Furthermore, the elements cannot be lost during installation of the surface drainage device or while it is undergoing repair or maintenance work.  
         [0067]     The damping sections  16 ,  16 ′ in this embodiment are constructed as protrusions  17 ,  17 ′ above the level of a surface of the cover  7  that faces the body  2 , and as an integral component of the first fixing element  10   d . The protrusions  17 ,  17 ′ each extend in the long direction of the body  2 , on both sides of the flat first element  10   d , so that the protrusions  17 ,  17 ′ lie on the second fixing element  20   d . It is advantageous for the protrusions  17 ,  17 ′ at the first fixing element  10   d  to be made arbitrarily extensible in the long direction of the body  2 , so that they can extend beyond the second fixing element  20   d  and lie on the upper rim  6  or frame  5  of the body  2 . This is advantageous if it is desired to obtain a high damping action when the load imposed on the surface drainage device is high.  
         [0068]     The fixing element  10   d  itself is made flat and comprises two lug-like projections  12 ,  12 ′ and a central recess  14 , i.e. it is partially subdivided. If the element  10   d  is provided as a rigid element, for example has been cast along with the cover as a peg, material can be saved by providing this recess  14 . However, if the element  10   d  is made flexible, the recess  14  can produce an increase in flexibility, so that the process of catching the element, in this case within the complementary second fixing element  20   d , is simple and easily accomplished.  
         [0069]      FIG. 7  shows, likewise from the front, fixing elements  10   e ,  20   e  engaged with one another. The second fixing element  20   e  is basically similar to the one shown in  FIG. 6 . The element  20   e  in this embodiment is likewise inserted into the channel body  2  so that it is flush with the frame  5  that covers the upper rim  6 . However, it consumes very little material and is simply designed. The lug-like projections  22 ,  22 ′ are only partially attached to the associated side walls  30 ,  30 ′ of the fixing element  20   e , so that a lug extension is spaced apart from the associated side wall  30 ,  30 ′.  
         [0070]     In this embodiment it is advantageous for both fixing elements  10   e ,  20   e  to be flexible, but the projections  22 ,  22 ′ of the second fixing element  20   e  should be harder than the projections  12 ,  12 ′ of the first fixing element  10   e . Thus the first fixing element  10   e  is easily inserted, because the projections can be pushed toward the side walls  30 ,  30 ′ with a springy action. Conversely, the locking is easily released owing to the elastic deformability of the projections  12 ,  12 ′.  
         [0071]     The damping section  16  in this embodiment is an integral component of the first fixing element  10   e  and/or the second fixing element  20   e . A height H of the first fixing element  10   e  perpendicular to the long direction of the body  2  is here dimensioned such that the first fixing element  10   e  bears against the floor of the cavity  23  of the second fixing element  20   e , producing a space that separates the locked cover  7  from the upper rim  6  of the body  2  embeddable in the ground. Advantageously, this construction is easy to implement, and a fixing element  10   e  with the desired height H can be simply and economically manufactured.  
         [0072]      FIG. 8  shows in perspective rod-like projections  22  that act as a second fixing element; these are rigid elements, ensuring an extremely simple and economical but nevertheless secure locking of the cover  7 . The rods  22  in this embodiment are fitted into a frame section that is perpendicular to the part of the frame that covers the upper rim  6  of the body  2 , and therefore extend outward from the frame  5  in the direction toward the middle of the channel. The rod-like projections are preferably made of V2A steel. A corresponding fixing element  10   f  in this embodiment is accordingly made in the shape of a hook, such that the rod-like projection is received between the sections forming the hook. It is useful for a recess  13  to be provided to receive the rod, so that the latter is securely seated when the cover  7  is locked in place.  
         [0073]     In this exemplary embodiment the damping action is provided by the first fixing element  10   f . For this purpose a damping section  16  extends over the height H of the element  10   f , so that the first fixing element  10   f  lies on the frame  5  that covers the upper rim  6 , and the locked cover  7  is spaced apart from the upper rim  6  of the body  2 . Advantageously, this construction is easy to produce, and a fixing element  10   f  with the desired height H can be simply and economically manufactured.  
         [0074]     In principle it is possible for damping sections  16 ,  16 ′,  26 ,  26 ′ to be disposed both at the first fixing element and at the second fixing element (not shown here). The advantage here is that in addition to the damping action the protrusions  17 ,  17 ′,  27 ,  27 ′ interact with one another, so that they are exposed to less wear and tear.  
         [0075]     An extremely secure locking can be achieved when one fixing element is made of flexible material and the complementary fixing element is of stiff construction. When the complementary fixing elements are both made flexible but with different hardness, it is easier to initiate the locking process and/or to release it again and hence is suitable—as mentioned above—for surface drainage devices that are exposed to relatively slight forces and for which frequent removal of the cover is to be expected.  
       LIST OF REFERENCE NUMERALS  
       [0000]    
       
           1  Fixing device  
           2  Channel body  
           3  Wall of the channel body  
           4  Groove  
           4 ′ Groove  
           5  Frame  
           6  Upper rim  
           7  Cover  
           10   a ,  10   b ,  10   d - 10   f  First fixing element  
           11  Contact surface  
           11 ′ Contact surface  
           12  Projection  
           12 ′ Projection  
           13  Recess  
           14  Recess  
           16  Damping section  
           16 ′ Damping section  
           17  Protrusion  
           17 ′ Protrusion  
           20   a - 20   f  Second fixing element  
           21  Contact surface  
           21 ′ Contact surface  
           22  Projection  
           22 ′ Projection  
           23  Cavity  
           24  Opening  
           24 ′ Opening  
           25  Opening  
           26  Damping section  
           26 ′ Damping section  
           27  Protrusion  
           27 ′ Protrusion  
           28  Front wall  
           29  Back wall  
           30  Side wall  
           30 ′ Side wall  
           31  Upper wall  
           32  Projection  
           32 ′ Projection  
          B 4  Width of upper rim  
          B 10a , B 10b  Width of first fixing element  
          B 20a  Width of second fixing element  
          B 22  Width of projection  
          H Height of first fixing element  
          L Length of second fixing element