IE65916B1 - A cover means for an access or drainage shaft - Google Patents

Abstract

The device comprises a frame (1) and a removable grating (2) which is hinged along an axis X-X of the frame, which grating consists of a series of bars connected in pairs, by at least one tie and running perpendicularly to the hinge axis X-X of the grating (2). The grating (2) furthermore comprises two intermediate bars (19A, 19B) connected to the other bars of the grating by their ends opposite the hinge axis X-X and the free ends of which interact, by elastic bending of the bars (19A, 19B) in the plane of the grating, with means (13, 14), arranged on the frame (1), for holding the grating (2) in the open and closed position. <IMAGE>

Description

This invention relates to cover means for an access or drainage shaft comprising a tilting removable grid which when the device is in the closed position rests in a frame which is sealed to the ground.

A grid mounted in a pivoting manner within its supporting frame which can be locked in the closed position through a median bar whose end located opposite the hinge axis snaps into a stop on the frame through elastic deformation is also known from document EP-A-0085306.

Such a cover device nevertheless has the disadvantage that it will not hold the grid in the open position.

A grid which is hinged on its frame and of which at least one bar 15 is equipped at its end opposite the hinge axis with elastic fingers which lodge beneath a projection in the frame in the closed position is also known from document EP-A-0282872. Here again, although such means makes it possible to lock the grid effectively in the closed position, they do not make it possible to prevent premature closure when the grid is in the open position.

In addition to this, French patent application no. 89 12 938 (FR__ A-2652606) lodged by the Applicant on the 29 September 1989 discloses a method and means for covering a drainage shaft comprising a grid which is hinged in a frame along a pivot axis of the grid corresponding to one side thereof, this grid being provided with bars connected to each other by means of struts.

The grid is divided along its pivot axis into a median portion and two lateral portions connected elastically to the median portion, one end of the median portion adjacent to the pivot axis being designed to bear against a corresponding surface of the frame by exerting a torque which opposes movement of the frame about its pivot axis.

An arrangement of this type described in the aforesaid patent makes it possible to ensure that the grid remains locked in order to prevent accidental opening of the shaft, and also to prevent acts of vandalism in the course of which the grid may be deliberately removed from its frame.

Furthermore, it ensures that the grid is held in the open position.

The invention is designed to effect a further improvement in the art described above by providing cover means in which on the one hand any accidental opening of the grid and on the other hand any premature closure thereof when it is in the open position are avoided through the elastic action of some members of the grid.

It therefore relates to cover means for an access or drainage shaft comprising a frame and a removable grid hinged on an axis X-X of the frame, comprising a set of bars connected in pairs by at least one strut and extending perpendicular to hinge axis X-X of the grid, characterised in that the grid also comprises at least one intermediate bar connected to the other bars of the grid by its end opposite hinge axis X-X, and whose free end acts through elastic flexion of the intermediate bar in the plane of the grid together with upwardly projecting means provided on the frame which hold the grid in the open and closed positions, these means comprising bevelled sloping surfaces which act together with sloping surfaces provided on the said intermediate bar.

The invention will be more particularly understood from the following description which is given purely by way of example with reference to the appended drawings in which: Figure 1 is a plan view of a shaft cover means according to the invention, Figure 2 is a section along the line 2-2 in Figure 1, • 35 Figure 3 is a side view of the cover means showing the grid in the open position and in the closed position, Figure 4 is a plan view of the grid of the cover means according to the invention, - Figure 5 is a partial perspective view of the cover means according to the invention showing the means for holding the grid in the open or closed position, and Figure 6 is a partial perspective view similar to Figure 5 showing a variant of means for holding the grid.

With reference first of all to Figures 1 and 2, it will be seen that the cover means according to the invention comprise a frame 1 which is designed to be sealed into the ground, e.g. in the surface of a roadway, at the top end of a drainage or access shaft (not shown) and a removable hinged grid 2 which forms a cover.

Frame 1 has a generally square or rectangular shape in plan and 20 has a vertical skirt 3 provided around its periphery by a peripheral bearing surface 4 which serves to seal the frame and an inner collar 5 which serves as a bearing surface for grid 2.

Two opposite sides 6, 7 of grid 3 each have a cavity 9 having an axis X-X parallel to side 8 in the immediate vicinity of side 8 which is perpendicular to them, the two cavities 9 being coaxial.

Skirt 3 terminates in a side 10 opposite and parallel to side 8.

Each cavity 9 is provided in skirt 3 of frame 1 above inner collar 5 approximately halfway up between this collar and the top of skirt 3.

The part of collar 5 which is integral with side 8 of skirt 3 has two openings 11A, 11B close to its ends which define between them an intermediate portion 12, wherein each of the two ends parallel to sides 6 and 7 of the skirt have a bevelled surface 13 directed towards the inside of the frame and standing away from the opposite wall of corresponding opening (11A, 11B).

Each extremity of intermediate portion 12 of the collar bounded by openings 11A, 11B also supports a stop 14 which projects towards the top of frame 1 and is integral with side 8 of skirt 3.

The arrangement of bevelled surface 13 and stop 14 is clearly shown in the perspective view in Figure 5.

In cross-section each stop 14 has the shape of a rectangular trapezium. It is parallel to sides 6 and 7 of the frame and as a consequence to the bars of grid 2, and on its side facing corresponding opening 11A, 11B has a sloping or ramp surface 15 which ends in a horizontal summit 16.

Grid 2, of a generally rectangular shape, comprises a set of parallel bars, each bar being connected to the adjacent bars by means of at least one strut.

As may be seen clearly in Figure 4, the grid comprises two outer 25 bars 17 which each have a pivot close to one of their ends which is designed to be housed in one of cavities 9 in frame 1, the two pivots 18 being coaxial, along the axis Y-Y.

Two intermediate bars 19A, 19B which are connected by their ends opposite to hinge axis Y-Y of the grid to outer bars 17 on the one hand and bars 20 of a central part of the grid on the other by means of single struts 21A, 21B, each having at its free end close to axis Y-Y a downward vertical projection 22 whose innermost longitudinal face, i.e. the one closest to the centre of grid 2, has a sloping or ramp surface 23, the inclination of this ramp being identical to that of corresponding ramp 15 of associated stop 14. Connecting bars 20 comprising the central part of the grid complete the latter.

In order to mount grid 2 in its frame 1, the former being presented perpendicular to the plane of the frame, the grid is 5 compressed at the free ends of bars 17, this operation being possible through the natural elasticity of the material comprising grid 2, which is constructed e.g. of spheroidal graphite cast iron. Pivots 18 are thus placed facing cavity 9 in frame 1, which they enter when the compression force is released.

Starting from the open position of the grid shown by a dotted and dashed line in Figure 3, to close the grid, grid 2 is pivoted about its axis of rotation Σ-Χ in the direction of arrow F until ramps 23 of intermediate bars 19A, 19B come into contact with bevelled surfaces 13 of intermediate portion 12 of collar 5.

When ramps 23 come into contact with bevelled surfaces 13, they create a couple between collar 5 and bars 19A, 19B which opposes further rotation of grid 2, thus preventing it from closing prematurely.

To overcome this couple a downwardly directed force is. applied to grid 2, and the force of this causes ramps 23 to slide along bevelled surfaces 13 of intermediate part 12 of collar 5. This sliding movement causes bars 19A, 19B to be displaced elastically from their normal positions, as shown by a dotted and dashed line in Figure 1, so that projections 22 of each of bars 19A, 19B can pivot about axis X-X as a result of the presence of corresponding openings 11A, 11B provided in the collar 5 of frame 1 which allows corresponding projections 22 to pass.

Bars 19A, 19B are displaced in the plane of grid 2.

When the grid reaches the closed position, inclined ramps 23 provided on projections 22 of bars 19A, 19B come into contact with sloping ramps 15 of stops 14 borne by the ends of intermediate portion 12 of collar 5 as a result of intermediate bars 19A, 19B being brought together elastically, and thus create a couple which opposes accidental opening of grid 2.

It will be noted that the ends of bars 17, 20 of the grid, other than intermediate bars 19A and 19B, which are located in the vicinity of the axis of rotation Σ-Σ of the grid, do not provide an obstacle to rotation of the latter because of the fact that their end surfaces adjacent to axis Σ-Σ have a spherical or cylindrical shape centered on axis Σ-Σ, and have a radius such that these extremities never come into contact with either skirt 3 or collar 5 of frame 1 when the grid rotates.

As far as intermediate bars 19A, 19B are concerned, the existence of projections 22 located at a distance greater than its radius from axis Σ-Σ makes it necessary to provide openings 11A and 11B in collar 5, and these prevent obstruction to rotation through contact between projections 22 and collar 5 of frame 1.

In order to open grid 2 a lifting force has to be applied to it with sufficient force for the couple which it engenders to be greater than the resistant couple resulting from contact between ramps 23 of projections 22 of intermediate bars 19A and 19B and ramps 15 of stops 14 which are of one piece with frame 1.

The lifting movement of grid 2 causes sloping surfaces 23 to slide on ramps 15 of stops 14 and as a result causes a lateral elastic displacement of bars 19A, 19B with respect to their θ resting positions.

In general a bar forming a lever is used to ensure this displacement.

Intermediate bars 19A and 19B are displaced in the plane of grid 2 by elastic deformation. Then, as rotation of grid 2 continues, the corresponding projections 22 on bars 19A and 19B engage in respective openings 11A and 11B in collar 5 thus permitting the rotation of grid 2 about axis X-X to continue.

When the grid is placed in its open position, projections 22 again make it possible, through contact with bevelled surfaces 13 of intermediate part 12, for bars 19A, 19B to return towards each other into their resting position by elastic recovery, so that the grid is again secured against any premature closing movement.

The position of stops 14 of frame 1 between intermediate bars 19A, 19B and the respective orientations of ramps 15 of stops 14 and 23 of projections 22 have the effect that the elastic bending of the bars is accompanied by a movement of the bars away from each other.

The provision of stops which are integral with frame 1 outside the intermediate bars and orientation of the ramps of the stops and those of the ends of the intermediate bars in such a way that elastic bending of the bars in the plane of the grid when the grid rotates is accompanied by a movement which brings the bars closer together may also be envisaged.

In the embodiment described with reference to Figures 1 to 5, the 25 intermediate bars, which ensure that the grid is immobilised in both, the open position and the closed position by elastic deformation in the plane of the grid by acting with both ramps 15 of stops 14 borne on collar 5 and with bevelled surfaces 13 of intermediate part 12 of the collar have downwardly directed 3θ projections 22 which make it necessary to provide openings 11A, 11B in collar 5 in order that these projections may pass as the grid rotates.

An embodiment in which the intermediate bars have no projections, but have ends of a cylindrical or spherical shape, identical to those of the other bars such as bars 17 and 20 of the grid, may also be envisaged.

Such a variant is partly illustrated in Figure 6. This figure shows one of intermediate bars 29B whose end 30 is of a cylindrical shape of radius R such that when the grid to which bar 29B belongs is mounted in frame 1 the axis of cylindrical surface 20 is the same as axis X-X of rotation of the grid.

This being the case, when the grid is caused to rotate, the surface of the end of bar 29B never comes into contact with either skirt 3 or collar 5 of frame 1.

In this embodiment there is therefore no purpose in providing openings to allow any part of the end of bar 29A to pass when it is caused to rotate.

In order to ensure that the grid is immobilised in the open and closed position, frame 1 has stops 31 which extend over the full width of collar 5 parallel to the bars of the grid. Each of these stops 31 includes a lateral ramp 32 which is designed to act together with a complementary ramp 33 provided on each bar 29 B so as to ensure elastic movement in the plane of the grid when the latter are rotated and an end bevel 34 which through acting together with corresponding bar 29B allows the said bar to return to the resting position when the grid is in the open position so as to immobilise it against any premature closing movement.

In the examples which have been described with reference to the drawings, the grid of the cover means comprises two intermediate bars which hold the grid in the open and closed positions by acting together with means provided on the frame.

It will also be understood that the grid may have only a single intermediate bar located preferably in the central part of the grid which acts together with the corresponding securing means provided on the grid.

Claims (9)

1. Cover means for an access or drainage shaft comprising a frame (1) and a removable grid (2) hinged along an axis X-X on the frame, comprising a set of bars joined in pairs by at least one strut and extending perpendicularly to the hinge axis X-X of 5 the grid (2), characterised in that the grid (2) also comprises at least one intermediate bar (19A, 19B; 29B) connected to the other bars of the grid by its end opposite the hinge axis X-X and whose free end acts together with upwardly projecting means (13, 14, 15; 31, 32, 34) holding the grid (2) in the open and closed 10 positions, provided on the frame (1), through elastic bending of the intermediate bar (19A, 19B; 29B) in the plane of the grid, these means comprising chamfered sloping surfaces (13, 34; 15, 32) which act together with sloping surfaces (23, 33) provided on the said intermediate bar.

2. Cover means according to claim 1, characterised in that the grid comprises outer bars (17) which are provided with pivots (18) at the free ends thereof which engage through elastic bending of the outer bars (17) in corresponding cavities (9) in 20 the frame (1), two intermediate bars (19A, 19B; 29B) each being connected to an outer bar (17) by a single strut (21A) and to a bar (20) of a central part of the grid through a single strut (21B). 2 5

3. Cover means according to either of claims 1 and 2, characterised in that each of the intermediate bars (19A, 19B) of the grid (2) has at its free end adjacent to the hinge axis of the grid in the frame (1) a downwardly pointing vertical projection (22) whose inner longitudinal face has a sloping or ramp surface (23) which acts together with a sloping surface (15) of a stop (14) which projects towards the top of the frame (1), fixed thereto and extending parallel to the bars of the grid (2), the said stops (14) forming the means for holding the grid (2) in the closed position by acting together with the projections (22) on the intermediate bars.

4. Cover means according to claim 3, in which the frame (1) is provided with an inner supporting collar (5) for the grid (2) in the closed position, characterised in that the openings (11A, 11B) for passage of the projections (22) from the intermediate 5. Bars (19A, 19B) when the grid rotates are fitted in the inner collar (5) of the frame (1).

5. Cover means according to claim 4, characterised in that the means for holding the grid (2) in the open position comprise 10 bevelled surfaces (13) sloping towards the interior of the frame (1), provided on one of the walls of the openings (11A, 11B) which bound an intermediate portion (12) of the collar (5) and standing away from the other walls respectively of the corresponding openings.

6. Cover means according to claim 5, characterised in that the stops (14) acting together with the projections (22) are located along the walls of the openings (11A, 11B) incorporating the said bevelled surfaces (13).

7. Cover means according to either of claims 1 and 2, characterised in that each of the intermediate bars (29B) of the grid (2) comprise a free end close to the hinge axis of the grid of the frame (1) in a maimer appropriate to enable it to turn about the hinge axis without coming into contact with the frame (1) and in that stops (31) which are parallel to the bars of the grid, and are provided with sloping surfaces (32) acting together with corresponding sloping surfaces (33) of the intermediate bars (29B), forming the said means for holding the grid in the closed position, are provided on the frame (1).

8. Cover means according to claim 7, characterised in that each of the stops (31) forming the said means holding the grid in the closed position comprises a bevelled terminal surface (34) sloping towards the interior of the frame, the bevelled surfaces (34) forming the said means for holding the grid in the open position together with the ends of the corresponding intermediate bars (29B).

9. A cover means according to claim 1, substantially as hereinbefore described with reference to the accompanying drawings. »