WO 2004/007850 Al ¡: I! ? I!
Publisked: For Two-letter codes and other abbreviations. refer to the "Gulcl- - WÍÍ / I intemational se rch repon tice Notes on Codes and Abbreviations" appearing at the beginning- - befare the expiration of the time limit for amsnding uie ning of each regular issue of the PCT Gazette. claims and to be republished in the event of receipt of amendments
1
A FRAMEWORK TO DELIMITATE AN INCOMING AND SETS
RELATED
DESCRIPTIVE MEMORY
The present invention relates to a framework for delimiting a recess, and also refers to the sets related thereto. In particular, the invention relates to a frame for delimiting the open upper edge of a downwardly extending recess formed in the floor or in a floor similar to the floor. Examples of such frames include frames for inspection manhole covers, drains and sumps, and culvert screens. The invention relates, without limitation, to all frames of these types. Accesses to manholes provided with a frame including an upright peripheral wall having a flange projecting outwardly from a lower part of the frame to anchor the frame in an embedment such as mortar or other means have long been known. materials. A frame of this type is intended to be installed at the top of for example, a drain, sewer, inspection chamber or similar recess extending downward from a surface such as 2.
floor or a floor similar to the floor or flush with it. The frame defines a delimitation in the open upper limit of the incoming one. Inside and below the upper flange of the upright wall there are formed seats secured to the frame for one or more cover members. In the specific case of the frame of a manhole, the cover members are typically heavy, substantially undrilled plates (full or blind), which close or seal the opening delimited by the frame. In other applications such as culverts, drains and drains, the lid defines a lattice by the fact of presenting perforations in multiple places. Therefore, said lids serve to allow the passage of, for example, rainwater into the interior of the recess, simultaneously preventing the entry of leaves, stones or other debris carried by it. Regardless of the precise nature of the cover plates, it is well known to provide three seats secured to the upright wall in a triangular pattern. Typically, the seats represent surfaces oriented substantially upwards, which may be flat or (in some known arrangements) be configured so as to cooperate with the surfaces, facing downwards, of members or other construction details provided on the underside of a cover plate of the type previously described herein.
3
The use of three seats in a triangular pattern makes the cover "not rocking" (non rocking), since an object supported in three points that are separated from each other in order to define a triangle, is inherently stable without any need for specific leveling measures. Another advantage of the use of seats that define a triangular pattern is that in the case of a frame that is a paraelogram and more specifically rectangular to be observed in plan, the triangular pattern lends itself, and this is convenient, to the use of pairs of triangular lid plates abutting each other along adjacent edges in order to efficiently occupy the opening delimited by the frame. By using this principle, it is possible to comfortably close a square opening by means of a pair of cover plates each of which is a right angle triangle supported on seats positioned at their corners., whose plates abut each other along their hypotenuses. Similarly, a rectangular opening can be closed by two pairs of lids of this type, each supported, so that it can not be rocked, at its vertices by seats defining a series of triangular patterns. It is also known to support square and circular covers by frames, as described herein, again by using triangular patterns of seats, so as to define supports that do not allow the chair. Although the non-rocking combinations of frames and covers, just described, have been installed on a large scale, they nevertheless suffer from certain disadvantages, as follows: The non-rocking covers do not remain indefinitely free from rocking. In areas of intensive use (for example, heavily traveled roads, which causes repeated impulses that affect the lids), the seats of the lids, and the covers themselves, tend to wear out. This can cause the number of points on the lid that come into contact with the frame to increase. This can be a potential cause of a rocking arrangement that can be undesirably noisy. As disclosed in document FR-A-2 797 647, there are disadvantages associated with the use of three lid seats arranged in a triangular pattern, when the lid itself is not triangular but for example rectangular or circular. This is because the forces acting on the cover in places that define a lever arm with respect to one or the other of the seats can cause distortion, wear and other failures of the lid and frame combination, thereby covers become noisy and / or dangerous during use. In FR-A-2 797 647 a solution to this problem is proposed, consisting of providing elastically deformable pads on the lower sides of the caps in places of 5
the same ones that are located at a distance from the seats. However, this solution is complicated manufacturing and installation. On the other hand, the elastically deformable pads will wear out considerably faster than the covers to which they are secured. This in turn means that the lids can be mistakenly discarded and replaced, just because the elastically deformable members have worn out, before the lids have actually arrived at the end of their useful service lives. Sometimes, under heavy duty conditions, the frames move with respect to the delimiting means by which they are secured in the upper part of a recess. Said movement results in the inclination of a frame in such a way that the covers can settle obliquely on the seats and become able to rock. If the frame sinks, the covers can get caught in the projections in the upper part of the opening, which makes them roar noisily when they receive impacts. It is known the possibility of hinges the covers to the frames, especially in the case of Inspection mouths. Since frames and lids are usually made of cast iron and the lids are usually very heavy, the hinges of the lids to the frames reduce the mass (weight) that the service personnel have to hoist in order to open each one of the tops and to be able to accede to the entrante located underneath the cover.
6
In EP-A-0 808 951 a hinged arrangement of covers of this type which are formed by triangles occupying a rectangular frame is revealed. The hinges of the triangular lids are arranged on adjacent sides of the frame, so that even in the case of a rectangular four-manhole, it is possible to have free access to the recess from at least one of the sides of the door. the same. However, in fact this provision is not optimal for the needs of personnel accessing underground services, for example in the case of telecommunications or the field of public services. For example, in the case of telecommunications, sufficient access is required to the cable ducts and to the inspection chambers in order to insert, for example, equipment to blow the cables, maintenance equipment and extensive cable runs therein. In general terms there is a need for an improvement in the accessibility of the frame and cover combinations of the inspection ports intended to be used for underground services. According to a first aspect of the invention, a frame is provided for delimiting the open upper end of a recess, extending downwards, formed in a floor or in the ground, the frame comprising an upright peripheral wall having a flange which protrudes outwardly from the frame and which can be embedded in a means in order to immobilize the frame with respect to said recess; and the frame includes, secured to it, within the peripheral wall, one or more seats for a 7
lid that can be inserted in the frame, and the peripheral wall surrounds at least a part of the lid; each of the seats including a seat member that bears thereon an elastically deformable and removable pad from which at least a portion protrudes from the seat member in order to provide an elastically deformable seat surface which can be engaged by a part of said cover, each of the seats including a cuboid block of material defining a shoulder that in use faces upwards and which is used by the inclined frame to define respective edges of upper and lower shoulder, the directions of inclination being of the protrusions that contribute to the self-centering of a cover supported by that. According to a second aspect of the invention, there is provided a manhole assembly comprising a frame for delimiting the open upper end of a recess extending downwards formed in a floor or in the ground, the frame comprising a wall upright peripheral having a flange projecting outwardly therefrom and which may be embedded in a means so as to immobilize the frame with respect to said recess; and the frame includes, secured to it and within the peripheral wall, one or more seats for at least one lid that can be inserted in the frame; the peripheral wall surrounds at least part of the lid; one or more lids that can be inserted into the frame and removed from it; and at least four elastically deformable pads each of which interconnects one of said covers and one of said covers.
of said seats when the lid, or each of the covers, is inserted into the frame, the elastically deformable pads being located at the corners of a quadrilateral defined in this way on the side in use that is the bottom, said one or more caps, and where the seat or each seat also includes a cuboid block of material defining a shoulder that in use faces upward and which is used by the inclined frame to define respective edges of the upper and lower shoulder, the directions of inclination being of the protrusions such that they contribute to the self-centering of a cover supported by it. Regardless of whether the invention is implemented in the form of a frame or a manhole assembly, the elastically deformable pad, or each of them, can be releasably secured in said seat member. For reasons of convenience, the term "manhole" is used herein to designate both an assembly in which the lid, or each of the lids, is not perforated (i.e., a conventional manhole assembly). ); and an arrangement in which one or more covers are / are perforated (eg, as in a sewer or drain grate). As used herein, the term "manhole assembly" is not limited to only those provisions delimiting entrants that are dimensioned for human access. The term encompasses within its joint scope both larger and smaller.
9
The use of an elastically deformable pad secured to the frame makes it possible to avoid the problem, which is evident in the prior art, of the covers of manholes that carry elastically deformable members secured to them, and which are discarded before they have reached their lives effective service tools. On the other hand, the optimum securing of the elastically deformable pads in the seats formed in the frame, allows the replacement of the covers economically, which tend to wear out more quickly than the frames. It is preferable that the erect wall be rectangular when viewed in plan, and that the frame include one of said seats in at least two corners of the rectangle thus defined. An arrangement having two of the seats in corners of a rectangular frame is advantageously suitable for the covers of the manholes used in the access to the underground services. It is convenient that the rectangular frame can include one of said seats in each of the four corners of the rectangle. This arrangement is suitable for manholes, drains and sumps, and culverts that include one or more covers that are not secured by hinges to the frame. In an alternative embodiment, the upright wall of the frame is rectangular when viewed in plan, and the frame includes at least one of the seats partially along at least one side of the frame.
rectangle so defined. This arrangement is particularly suitable for frames that require more than one lid to close their openings. Regardless of the precise arrangement of the seats in the frame, it is preferable that the seat member, or each of the seat members, include a cuboidal block of material defining a shoulder which is oriented upward and which has been formed in use conditions. in it a notch that defines a slot that is open in the boss that faces upwards and in another face of the cuboidal block. This arrangement offers an advantageously simple way to immobilize the elastically deformable pad with respect to the seat member, while still allowing a portion of the elastically deformable pad to protrude from the cuboidal block defining part of the seat member. It is more preferable that the notch defines a base that in the use of the frame is located below the shoulder; that the width of the notch is between the base and its opening in the shoulder; that the elastically deformable pad includes a coupling portion having a cross section of a general shape that is complementary to the cross section of the notch; and that the pad is restrained against its relative movement with respect to the notch in the vertical direction in use, by engaging the engaging portion in the notch.
eleven
The aspects just described make the design of the elastically deformable pad advantageously simple and easy to insert into the cuboidal block, without the need for mechanical assistance. In particularly defined embodiments, the pad includes a region of a material that is secured to the coupling portion and protrudes from the seat member through the opening in the shoulder. This is a particularly efficient way to provide a portion of the pad that projects beyond the cuboidal block so as to provide a seating face against which a portion of the lid can rest. It is convenient that the opening on the other side of the cuboidal block is of a configuration and orientation that allow the insertion of the pad in the slot and its removal therefrom, in a direction different from the direction in use that is vertical. This aspect allows the easy mounting of the pads within the cuboidal blocks, without detriment to the action of the notch which restricts the vertical movement of the pads. The nature of the opening of the other face of the cuboidal block also allows, and this is advantageous, the replacement of the pads. Therefore, the pads can provide replaceable wear surfaces of the frames, thereby effectively prolonging the overall life of the frames as compared to frames of the prior art.
12
In a preferred embodiment, when the frame is in use, the shoulder facing upwards is inclined so as to define respective upper and lower shoulder edges. It is also preferable that the frame includes a pair of seat members that are separated from each other in a direction that in use is horizontal and whose upturned projections are mirror images of each other, whereby the upper edges of the shoulder define the separated regions further. away from the pair of seat members. From this it follows that when a lid is placed on the frame in such a way that the coupling members of the lid engage with the respective seats of the pair, the opposite, inclined nature of the seats tends to cause the frame to center around the frame. himself between the seats. The invention also encompasses a frame having one or more covers resting on it. For the avoidance of doubt, as used herein, the word "lid" includes, but is not limited to, solid lids (such as manhole covers); the drains and drains; and the sewers of the sewers. It is preferable that the frame and each of the covers include cooperating connections and particularly hinge parts formed respectively on one side of the lid and one side (eg, a first edge) of the frame, thereby the lid, or each of the covers, is 13
secured, by hinges, to the first side of it; and the cover, or each of the covers, covers the frame from a first side to a second side (eg, a second edge) opposite the first side. In an arrangement such as the one mentioned above in which the lid, or each of the lids, is secured, by means of hinges, to the frame, the preferred embodiment of the latter is a rectangular configuration. However, other configurations are possible, as described in the following. It is convenient that the second side be secured to it a pair of seats that can be coupled by the underside of each of the covers. It is even more preferable that the frame be essentially rectangular and include a plurality of the covers arranged side by side, all the covers being hinged on the same side of the frame, whereby the covers can be opened in order to leave a expeditious access to the entrant on all the remaining sides of the frame. The aforementioned provisions provide particular advantages when the framework is a manhole frame used in the field of telecommunications. In fact, the arrangement of the invention allows for the first time the provision of a rectangular frame whose covers have hinges only along one of the edges of the rectangle, whereby three sides are free through which operators can access to the entrance located under the frame.
14
More particularly, in certain embodiments of the invention the upright wall is rectangular when viewed in plan; and each of the covers is rectangular, the main axis of each of said covers being located perpendicularly to the main axis of the rectangle defined by the upright wall; and the edges of said adjacent caps are separated from each other in such a manner that the caps are capable of substantially covering the entire opening defined by the recess. This allows the provision of a rectangular manhole frame whose covers are a series of elongated parallel rectangular sheets, which cover from one side of the frame to the other side, and which are parallel to the minor axis of the rectangular frame. In one embodiment of the invention, each of the covers is substantially undrilled, whereby the combination of frame and cover defines a manhole. In an alternative arrangement, one or more of the covers have perforations, so as to define a lattice, a grid, or a drain. The width of the flange of the frame can vary, and this is preferable, from one place to another through the periphery of the frame. This allows efficient utilization of the frame material by the provision of wider flange portions in those regions in which there is a particular need for the flange to adhere the frame to the medium; and narrower flange portions in other places where there is less need for adhesion.
fifteen
It is preferable that the frame includes projections or recesses formed in one or more surfaces thereof which are recessed in a means of adherence of the frame in the middle, whereby the frame is stiffened. Said projections or recesses reinforce the adherence of the frame in the middle of the adhesion; and they also improve the resistance, and hence the service life, of the frame. It is expedient for the projections or recesses to include an ordered array of ribs formed on a surface of the rim that faces upwards and / or downwards. On the other hand, the ribs of the array are preferably elongated and parallel to each other, and protrude, all of them, at approximately the same distance from the flange. It is even more preferable that the frame has a general polygonal shape when viewed in plan, and that the elongated axis of each of the ribs has a general direction to a diagonal of the polygon thus defined. The preceding aspects of adhesion and stiffening ribs have proven to be particularly effective in conferring good performance on frames. In addition to the above-described advantages of the inventive arrangements, the following desirable aspects relate to the use of elastically deformable pads: The possibility of caps and frames becoming noisy during use is considerably reduced, since that the pads serve to isolate the components thereof with each other.
16
The elasticity of the deformable pads may be chosen so as to mimic that of the bonding means and / or surrounding terrain in which the frame is installed. This reduces the likelihood of pulses transmitted to the frame (for example, due to passing vehicles) causing a shift of the frame with respect to the adhesion means. The arrangement of the invention is considerably simpler than that proposed in FR-A-2797 647. A description of preferred embodiments of the invention is now given, by way of non-limiting example, and reference is made to the accompanying drawings, in which which: Figure 1 is a top plan view of the frame of a manhole according to the invention, including in dashed line a manhole cover that can be housed therein. Figure 2 is a cross-sectional view, on the arrows A-A of the Figure, parts of the lid being included. Figure 3 is a cross-sectional view, on line B-B of Figure 1, parts of the lid being included. Figure 4 is a horizontal cross-sectional view, on lines C-C of Figure 3, showing an elastically deformable pad. Figure 5 is a vertical cross-sectional view, on line D-D of Figure 1.
17
Figure 6 is a vertical cross-sectional view on the line EE of Figure 1. Figures 7A and 7B are respectively a plan view and an elevation view of an elastically deformable pad shape that can be used in frames according to the invention. Figure 8 is a perspective view of a corner of the frame of Figure 1, the cover of which has been omitted for clarity. Figure 9 is a perspective view, of a second embodiment of the frame according to the invention, which is secured with hinges by means of a plurality of inspection manhole covers. Figure 10 is an enlarged, perspective view of the arrangement of Figure 9 in which one of the lids has been omitted, for clarity; and Figure 11 is a perspective view from below, of part of the arrangement of Figure 9. Referring to the drawings, there is shown a frame 10 for adhering the open upper end of a recess extending downward (FIG. such as, but not limited to, a duct, a manhole, an inspection chamber, a fire hydrant chamber, a water main, or similar installation) formed on a floor or ground, including an upright peripheral wall 1 from which a flange 12 protrudes outwards which can be embedded in a medium (not shown) of
way to immobilize the frame with respect to an incoming, as previously mentioned. In the embodiment of Figure 1, the peripheral wall 11 is essentially rectangular and is provided with pairs of walls parallel to each other, straight and upright, and with 4 rounded corners 1a. The corners 11a are primarily rounded in that the frame 10 has been cast from a material such as iron. As is well known, it is more reliable to cast these pieces with rounded corners than with sharp angles. In fact, the entire frame 10 is essentially rectangular when seen in plan. The flange 12 protrudes from the base of the upright wall 1 and extends around the entire rectangular periphery of the frame 0. The frame 10 includes, secured to it within the peripheral wall 11, four seats 13, 14, 16 and 17. In the embodiment of Figure 1, there is a seat secured in each of the corners 11a of the peripheral wall 11. Each of the seats is located within the peripheral wall and, as shown in the Figure 12 which illustrates in a partially sectioned view a portion of the seat 13 visible in Figure 1, extends partially along the height of the wall 11 from the bottom thereof. The seats 13, 14, 16, 17, are intended to be dockable by a cover 18 which, as shown in Figure 1, is an outer periphery 19
whose shape complements or matches the inner side 11 b of the wall 11. The configuration and size of the lid 18 are therefore such that the lid 18 can be inserted into the frame; the peripheral wall 11 surrounds the lid 18. The lid can be completely removable from the frame as would be the case with the traditional manhole covers and be removably secured thereto. As an alternative, the embodiment described herein refers to a lid pivotably connected to a frame, particularly by means of a hinged connection. As best shown in Figure 2, each of the seats, exemplified by the seat 13, includes a seat member 21 having secured thereto an elastically deformable pad 19 part of which protrudes from the seat member 21 so as to providing an elastically deformable pad that can be engaged by a member 22 projecting down from the underside of the lid 18, at the edge thereof adjacent the seat. The part 19a of the pad projecting above the seat member 21 can best be seen in Figure 2, which is a vertical cross-sectional view of the seat 30 taken on the arrows BB of Figure 1, i.e. in such a way that the line of the section does not pass through the pad 9. Therefore, Figure 3 shows part 19a of 20
the pad projecting above the upper edge of the seat member 21. The pad 19 is preferably manufactured from a material known as "Railpad". The seat member 21 is a cuboidal block of material which, in the embodiment shown, has been integrally cast together with the remainder of the frame 10. In other embodiments the block constituting the seat member 21 may have been manufactured separately of the frame 10 and having subsequently been secured to it for example by bolts, spikes, bevelling or welding. However, the integral casting of the block 21 is the preferred embodiment, due to the efficiency of the manufacturing process represented by the integral casting. The seat member 21 defines a shoulder 23 which in use faces upwards and has a groove 24 formed therein defining a groove that is open in the shoulder 23 as represented by the reference number 26 in Figures 1 to 8 and that also opens on another face 27 of the seat member 21, as exemplified by the reference number 28. The components 26, 27 and 28 can be better appreciated in Figure 8. As can also be better appreciated in the Figure 8, the notch 24 is essentially of the "dovetail" type, so as to define a base 29, that the frame being in use (i.e.
horizontally disposed as shown) is located below the shoulder 23. The width of the notch 24 tapers between the base and its opening, as indicated by reference numeral 26. The pad 19 includes a mating portion. 9b whose cross section has a general shape that is complemented with that of the notch 24. Therefore, the pad 19 is restrained against the notch 24 in the direction that in use is vertical, by engaging the tapered sides of the portion coupling 19 with the tapered sides of the notch 24. The protruding region 19a of the pad 19, in the embodiment shown, is simply a continuation of the taper thereof in the direction that is vertical in use, thereby the protruding portion 19a is narrow enough to fit through, and protrude above, the groove 26 formed in the shoulder 23. Of course, within the ranges Other shapes, sizes and configurations of the coupling portion 19a are possible of the invention. For example, portion 19a may include a series of projections (instead of a single projection). In addition, the coupling portion 9a does not need tapered sides as shown in the drawings. The opening 28 in the other face 27 of the cuboid block defining the seat member 21 has the same vertical cross section as the rest of the groove 24, whereby the pad can slide in and out 22.
of the notch 24 during the manufacturing and / or maintenance operations carried out in the frame 10. The orientation of the taper and the other aspects of the notch 24 are such that the sliding of the pad 19 in and out of the notch 24 has place essentially in a horizontal direction. Therefore, the direction of insertion and removal of the pad 19 differs from the vertical direction of the movement thereof which is restricted by the taper of the notch 24. The pad 19 is housed in the notch 24 by its manual sliding inside. of the notch, creating a wedge of interference in it. To insert the pad you do not need tools or other mechanical help. As best seen in Figures 2 and 8, the shoulder 23 slopes down from an upper edge 23a which is located adjacent the upright wall 11; to a lower edge 23b separated therefrom. The seat 17 disposed at the opposite end of the frame 10 of the seat 13 includes the seat member and a pad 19 which are mirror images of their counterparts constituting the seat 13. The seat 16 which is located at the diametrically opposite corner of the frame 10 to the seat 13, it is essentially identical to the seat 13, but rotated by 180 degrees. The seat 14 which is located at the diametrically opposite corner of the frame 10 to the seat 17, is essentially the same as the seat 7 but rotated by 80 degrees.
2. 3
Therefore, the seats 13, 14, 16, 17 define pairs of inclined shoulders that have pads protruding therefrom. The directions in which the ridges are inclined tend to cause the seat of the lid to center itself in the frame 10, inside the wall 11, the lid 8 being inserted therein. Although in the embodiment shown the projections 23 slopes downwards toward each other, it is within the scope of the invention to define other arrangements of the projections 23 that cause self-centering of a cover such as the cover 18 inserted into the frame 10. For example, the respective members of each pair of seats 13, 17 and 14, 16, could lean towards the center of the associated part of the peripheral wall 11, instead of downward as shown . Since the pads 19 are manually movable from the seat member 2, they can be replaced by new pads once worn, without having to replace another part of the frame. Referring now to Figures 9 to 11, there is shown a second embodiment of frame 30 according to the invention. The frame 30 has a rectangular general shape when viewed in plan and has an upright peripheral wall 31 which, when seen in plan, also has a general rectangular shape. An outwardly extending flange 37 extends around the outer periphery of the wall 31, from the outside.
lower part of it. The function of the rim 32 is similar to the function of the rim 12 in the embodiment of Figure 1. Along one of the sides 31a the upstanding wall 31 having formed thereon a series of eight blocks has been formed. hinge 33 arranged at equally spaced intervals. Each of the hinge blocks is integrally cast together with the iron of the remainder of the frame 30, and has an upper wall that terminates flush with the upper edge of the wall portion 31a. An opening 34 opens in the upper surface of each of the hinge blocks 33 in order to receive hinge parts in a manner described below. A series of four elongate rectangular caps, 36, 37, 38, 39, is secured by hinges, to the wall portion 31a by hinge portions protruding from a trailing edge of each of them in the respective openings 34. Each of the lids 36, protruding from its rear edge and seen in plan in Figure 9, a pair of hinge parts, whereby each of the hinge blocks functions so as to be secured, by hinge, to the frame 30 of a respective cover, 36, 37, 38, 39. Each of the covers 36, 37, 38, 39, covers the frame 30 from the first side thereof defined by the wall portion 31a, to a second portion of opposite wall, 31a.
25
As illustrated by the condition, partially open, of the lid 36 in Figure 9, the hinged arrangement is such that all of the four covers 36, 37, 38, 39, are hinged on the single side (31a) of the upright wall 31. Therefore, when the covers occupy, all of them, their open position, three sides of the rectangle defined by the frame 30 remain free and without obstacles. In the embodiment shown in Figures 9 to 11, the main axis of each of the covers 36, 37, 38, 39, is located perpendicularly with respect to the main axis of the rectangle defined by the upright wall 31. The edges of the adjacent lids are in their closed position, separated from each other in such a way that the lids are able to substantially cover the entire opening defined by the recess, so as to substantially seal it. Other arrangements of the caps are possible. For example, within the scope of the invention, rectangular caps having elongated main axes parallel to the elongated main axis of the rectangle defined by wall 31 are possible. Another arrangement is that in which a circular erect wall
31 can be closed by a series of lid leaf segments that are hinged along a common arch located towards one of the sides of the circle defined by the wall 31. In this arrangement there can be multiple rectangular caps or a single circular lid .
26
The removable nature of the covers with respect to the frame is such that if they wear out it is possible to replace one or more covers without having to remove or replace the frame. In the preferred embodiment shown in Figures 9 to 11, the underside of each of the covers 36, 37, 38, 39, is partially defined by a pair of parallel rails, 41, 42. Each of the rails parallel, 41, 42, is in its thickest part along the lid 36. At either end the depth of each of the parallel rails, 41, 42, is reduced so as to end in general terms with an adjacent member 43 whose function is to engage with a pad 44 which is similar to the pads 19 of the embodiment of Figure 1. Each of the members, 43, has a shoulder, oriented downward, which, as the associated lid 36 to 39 is in its closed position, it engages with the projecting upper portion 44a of said pad 44. Each of the pads 44 is housed in a seat member 46 which is similar to the seat member exemplified by the number of reference 21 in Figure 1. Po Therefore, each of the seat members 46 includes a notch 47 whose shape is as described for the notch 24 of Figure 1. The shape of the cross section and the dimensions of each of the pads 44 are similar to those of the counterpart pads 19 shown in Figure 1, whereby the portions 44a protrude into a 27
short distance above the shoulder 48, projecting upwards and defining the upper surface of each of the seat members 46. Since the location of each of the covers 36 to 39 with respect to the upright wall 31 is partially limited by coupling the hinge parts at the rear edge thereof with the hinge blocks 33, there is a smaller need than in the case of the embodiment of Figure 1 for the seat members to center the caps with respect to the upright wall. Therefore it is not necessary that the characteristics of the inclined shoulders of Figure 1 are present in the embodiments of Figures 9 to 11. However, in all other aspects, the pads 44a and the shoulders 48 are similar to the pads 19 and the shoulders 23 of the embodiment of Figure 1. The arrangement of Figures 9 to 1 includes the pads 44 located midway along each of the main side walls of the rectangle defined by the wall 31. The object of said positioning of the pads 44 is of course to allow the placement of a pad 44 in each of the corners of each of the rectangular caps 36 to 39. As a consequence of this arrangement, the pads 44 which are located away from the corners of the upright wall 31 are received in "conjoined" seat members 46a, as best seen in Figure 10. The seat members 46a are, to one of them, 28
essentially a pair of seat members 46 integrally formed together, in a "back to back" mode. Therefore, the openings of the groove 47 in the other faces of the seat members are, in the case of the seat members 46a, at opposite ends thereof, so as to allow easy insertion and removal of the pads 44. Figure 11 shows the pads 44 seen from the underside of the frame 30. As evident in the Figure, the pads protrude a short distance beyond the end of the seat members 46 so as to provide a projection on the other side. 49 of each of the seat members, whereby the pads can be gripped to assist in their insertion and removal with respect to the associated notch 47. While the embodiment of Figure 9 includes four rectangular caps, it is clear that within the scope of the invention it is possible to vary the amount of tapas. Virtually any number of the rectangular caps of the type shown in Figures 9 to 11 can be secured, by hinge, to a frame 30. In particular, the versions of a lid, two caps, three caps and four caps, of the invention, fall within the scope of the invention, as claimed. The frame itself can be modular, its size and shape being able to vary by adding or removing frame sections before they are embedded in the ground, in order to accommodate any number of covers, of any size.
29
The pads 44 visible in Figures 9 to 11 have essentially the same dimensions and sizes as those shown in Figures 7A and 7B. In addition, the materials with which the pads are made are the same as for the pads 19 of the embodiment of Figure 1. It is preferable that the covers 36 to 39 are cast iron. However, other types of material for the lids are also possible within the scope of the invention. Each of the openings 34 in a hinge block 3 defines a series of components that can be coupled by hinge pins protruding from lobes which in turn protrude from the trailing edge of each of the covers 36 to 39. In Figure 1 can be seen another feature of the frames 10, 30, of the invention: the Figure shows that the width of the flange 12 thereof varies from one place to another around the periphery of the frame. This feature saves material in those regions of the edge where its grip effect is minimal. Typically, the flange has its maximum width at the corners of the frame 10, when the latter is rectangular. On the other hand, Figure 8 shows a series of protrusions and recesses 51, 52, formed on the upper surface of each of the corners of the flange 12.
30
The protrusions and recesses may be present on any surface of the frame that is recessed in an aion means in order to secure the frame with respect to an opening; but the preferred location for them is on the upper and / or lower surface of the flange 12, as shown. In practice, protrusions and recesses 51, 52, define an ordered set of ribs (or staples) that are elongated and parallel to each other, and each of them protrudes to an extent that is usually the same, from the flange 12. The elongated axis of each of the ribs 51 is generally parallel to a diagonal of the rectangle defined by the upright wall 12 of the frame 10. The aspects of the width variability of the flange; and of the projections and recesses, can be used with the same convenience in the embodiments of the invention such as those shown in Figures 9 to 11, as in the embodiment of Figures 1 to 8. In another form of Embodiment of the invention, it is possible to secure a pattern of four elastically deformable pads, on the underside of each one of one or more covers of a manhole assembly, so as to couple the surfaces secured in the frame in places that are juxtaposed with respect to the pads when the case lid is closed. This arrangement confers the advantage of the use of elastically deformable pads, provided at 31
At the same time the pads on a component that is not a part of the frame.