Description

Field of the invention

This invention relates to pivot joints, kits of parts for assembling pivot joints, manhole bases, manholes, water transport systems, and methods of assembling water transport systems.

In particular, but not limited thereto, the invention can be applied in foul water drainage systems, more in particular below ground foul water drainage systems.

Background of the invention

Systems for transporting water, such as in public utilities, use a significant number of pipes which are connected to each other. The pipes can be connected directly to each other, e.g. with a spigot-socket joint or connected to other elements. For example, the system may comprise manholes, which provide respective openings to a confined space of the system. The manhole may for example serve as an access point for an underground public utility, allowing e.g. inspection, maintenance, and system upgrades. Manholes are often used in foul water, such as sewage and rainwater, drainage systems.

When laying the pipes, however, quite often the pipes are not exactly aligned, and there can e.g. be a mismatch in angle which does not match the angle requited to fit the pipes into the connector. For instance, when manholes are connected to pipes, quite often the pipes are not exactly aligned with the position of the corresponding connectors provided in the manholes. For example, the connectors may be at diametrically opposite sides of the manhole and the pipes may at an obtuse angle slightly less than 180°. For extensions, for example, the pipes have to be aligned exactly parallel to each other to allow the spigot of one pipe to be inserted in the socket of the other pipe. For other connections, such as bends, the pipes have to be aligned to the exact angle of the bend.

United States patent US4236738A discloses a ball joint for connecting the ends of a pair of pipes. The ball joint comprises a first assembly secured to the end of one the pipes. The first assembly comprises an inner ring member having an outer spherical surface, and an outer ring member extending axially over and spaced radially from the first ring member and having an outer spherical surface. The ball joint further has a second assembly secured to the other pipe. The second assembly comprises an inner annular body member having an inner spherical surface corresponding to the surface of the inner ring member and an outer annular body member extending axially over and radially spaced from the inner body member and having an inner spherical surface corresponding to the outer surface of the outer ring. The distribution of forces in this ball joint though is disadvantageous.

From European patent application publication number EP 1 141495, a manhole, referred to in this publication as a "gully", is known, which is provided with a pivot joint via which a pipe can be pivotably connected to the manhole base. Although this pivot joint has a compared to the ball joint known from United States patent US4236738 a better load distribution and in addition allows to connect pipes to the manhole, even when the pipes are, intentionally or unintentionally, slightly misaligned relative to the connectors in the manhole, a disadvantage of this known pivot joint is that the maximum angle of misalignment this joint allows is limited.

Summary of the invention

The present invention provides pivot joints, kits of parts for assembling pivot joints, manhole bases, manholes, water transport systems, and methods of assembling water transport systems as described in the accompanying claims.

Specific, but optional, embodiments of the invention are set forth in the dependent claims.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

Brief description of the drawings

Further details, aspects and embodiments of the invention will be described, by way of example only, with reference to the drawings. In the drawings, like reference numbers are used to identify like or functionally similar elements. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.

FIG. 1 schematically shows a perspective sectional view taken along the line ll-ll in FIG. 2 of a manhole with an example of an embodiment of a pivot joint.

FIG. 2 schematically shows a top view of the example of FIG. 1.

FIG. 3 schematically shows a perspective, sectional view of a pivot joint of the example of FIG. 1, seen from inside the manhole.

FIG. 4 schematically shows a perspective, sectional view of a pivot joint of the example of FIG. 1, seen from outside the manhole. FIG. 5 schematically shows a cross-sectional side view of the example of FIG. 1, taken along the line ll-ll in FIG.2.

FIG. 6 schematically shows a perspective view of an example of a pivot joint.

FIG. 7 schematically shows a cross-sectional view of the example of FIG. 6, taken along the line XI-XI in FIG. 11.

FIG. 8 schematically shows a cross-sectional view similar to the view of FIG. 7, illustrating fluid passages through the example of FIG. 6.

FIG. 9 schematically shows a side view of the example of FIG. 6.

FIG. 10 schematically shows a cross-sectional view, similar to the view of FIG.7 of the example of FIG. 6 in a neutral position.

FIG. 11 schematically shows a front view of the example of FIG. 6 in the neutral position

FIG. 12 schematically shows a cross-sectional view, similar to the view of FIG.7, of the example of FIG. 6 in a first pivoted position, pivoted to a maximum angle in a first direction.

FIG. 13 schematically shows a front view of the example of FIG. 6 in the first pivoted position.

FIG. 14 schematically shows a cross-sectional view, similar to the view of FIG.7, of the example of FIG. 6 in a second pivoted position, pivoted to a maximum angle in a second direction opposite to the first direction in FIGs. 12-13.

FIG. 15 schematically shows a front view of the example of FIG. 6 in the second pivoted position.

FIG. 16 schematically shows a cross-sectional, side view of an example of two elements of a water system connected by a pivot joint

FIG. 17 schematically shows a side-view of the example of FIG. 16.

FIG. 18-20 schematically show cross-sectional side views of various examples of pivot joints with different connectors for the second element.

FIG. 21-22 schematically show cross-sectional side views examples of alternative shapes of the cages of the first pivot member.

FIG. 23 schematically shows a cross-sectional view of parts of an example of a kit, suitable for assembling a pivot joint as in the example of FIGs. 6-9.

FIG. 24 schematically shows a side view of parts of the kit of FIG. 23.

FIG. 25 a-c schematically show side view of parts of the kit of FIG. 23 in successive stages of assembling a pivot joint.

FIG. 26 schematically shows a top view of an example of a water transport system. Detailed description of the preferred embodiments

Hereinafter embodiments of the present invention are described to the extent considered necessary for the understanding and appreciation of the underlying concepts of the present invention, and in order not to obfuscate or distract from the teachings of the present invention other details or aspects are not described in full detail.

Referring to Figs. 1-5, these show a manhole 1, as an example of an application of the pivot joint according to the present invention. Such a manhole provides an access point to an underground foul water transport system and can be used to inspect or access parts of a foul water transport system. In the following the term "manhole" is used to refer both to manholes which provide a physical access, such as for maintenance, to a human being entering into the manhole, as well as allowing inspection of the system, and to inspection chambers which allow for inspection only, such as sized smaller than a typical human being, and the pivot joint may be applied to either type. In a typical application, the manhole is installed below the ground surface and the top 11 of the manhole 1 is covered with a removable, exposed cover which is slightly recessed into, flush with or projecting from, the ground.

The manhole 1 comprises a manhole base 2 and a manhole shaft 10, which may also be referred to as a riser. The manhole shaft 10 extends upwards from the manhole base 2. As shown, the manhole shaft 10 extends from the base 2 up to the top 11 of the manhole 1. In this example, the top 11 is open and a (not shown) suitable manhole cover or grating can be provided at the top 11 to close-off the top. When placed below ground, the manhole shaft 10 provides an above ground (or at ground level) entrance to the manhole base 2 underground, e.g. for visual inspection from outside the manhole 1, or, depending on the specific dimensions, for inspection and/or maintenance equipment or a human to enter the manhole 1. The manhole base 2 comprises a bottom 20 and a circumferential wall 21 extending upwards from the bottom 20. The manhole shaft 10 is fixated to the circumferential wall 21 of the base 2. In this example, the manhole shaft 10 is a separate part removably fixated to the wall 21, but alternatively, the manhole shaft 10 may be an integral part extending upwards from the wall. As show, the manhole base 2, optionally together with the manhole shaft 10, forms a chamber which is to be buried into the ground and accessible from the surface to inspect the water transport system of which the manhole 1 is part.

As further shown in Figs. 1-5, the manhole base 2 is provided with a channel 23, in this example at the bottom 20 which is profiled to define the channel 23. In this example, the channel

23 extends between at least two ports 24,24' and water can flow through the channel 23, as indicated with the arrow 40, in a liquid flow direction from a respective one or more of the ports

24 forming one or more inlets to one or more of the other ports 24' the other ports thus forming respective outlets. In this example the channel 23 is an unbranched channel which connects two ports 24. Alternatively, the channel 23 may connect three or more ports 24 and for example be a branched channel. Such a channel can e.g. connect a single inlet port to several separate outlet ports, each via a respective branch channel, or comprise two or more crossing branch channels, each of which connects a respective inlet port to an outlet port, for instance. As shown, the channel 23 is upwardly open and formed in this example by a recess in a bottom plate 22 which extends between the ports 24 connected to the channel 23. As shown, the bottom plate 22 is located at some height above the bottom 12 at the outside of the manhole but forms the bottom of the inside of the manhole 1, said differently the bottom plate 22 defines the bottom of the chamber, which is at a distance from the actual bottom 12 of the manhole 1. The channel 23 is in this example a straight channel, but alternatively the channel 23 can be a bend-channel, e.g. to connect two pipes non-parallel to each other, and the manhole base can e.g. be a bend, a branch connector or other suitable type of manhole base connecting two or more pipes to each other.

The circumferential wall 21 can be provided with one, two, three, four or more ports. The ports may be distributed, in circumferential direction of the wall 21, equidistantly or spaced with a different spacing between successive ports. In this example only two ports 24,24' are shown. The ports in this example comprise (at the left- hand side in FIG. 5) an inlet port 24 and (at the right- hand side in FIG. 5) an outlet port 24'.

One or more of the ports 24,24' may be connected, when the manhole is installed below ground, to respective pipes 3,3'. To that end, one or more of the ports 24,24'may be provided with a pivot joint 4,4' which pivotably connects the port to the respective pipe. In the shown example, at an inlet port 24 an, in the flow direction, upstream pipe 3 is connected to the manhole 1 via a pivot joint 4 mounted in the inlet port 24. At the outlet port 24', an, in the flow direction downstream, pipe 3' is connected to the manhole 1 via another pivot joint 4' mounted in the outlet port 24'. The pivot joints 4,4' are mounted in a liquid-tight manner in the respective port 24,24', alternatively this may be a fluid-tight mount such that both liquids and gasses cannot leak through the ports.

The pivot joints 4,4' provide a, liquid-tight or fluid-tight, pivotable connection between the pipe 3,3' and the manhole base 2. Thus, as illustrated in FIG. 2 with the upstream pipe 3, one or more of the pipes can be connected to the manhole base 2 while misaligned relative to the desired or ideal orientation thereof. In the example of FIGs. 1-5, the desired orientation is parallel to the water flow direction 40 in the channel 23 at the respective port 24. In this example the flow direction is perpendicular to the tangential direction of the circumferential wall, and e.g. may the same for two ports but it will be apparent that in case of a non-straight channel, e.g. with crossings, bends or otherwise, the flow direction may differ between the ports 24.

Referring now to FIGs. 6-15, the following directions are indicated therein: an axial direction a, through the centre of a first pivot member 5 of the pivot joint from a first element side 42 to a second element side 43 (or vice versa) of the pivot joint 4; a radial direction r perpendicular to the axial direction, from the axial centre towards the outside of the first pivot member 5; a circumferential direction c, tangential to the radial direction r and perpendicular to the axial direction a; a pivot point P which defines the position of the pivot axis; a tangential direction t from the first element side 42 to the second element side 43 (or vice versa) along an, imaginary, circular arc around the pivot axis, which corresponds to the direction of rotation of the second pivot member 6 around the pivot axis. In the examples the tangential direction lies in the plane defined by the axial direction a and the radial direction, and is perpendicular to the circumferential direction c. The tangential direction t is not parallel to the axial direction a nor to the radial direction r.

Referring specifically to FIGs. 6-9, the example of the pivot joint shown therein may be used as the pivot joint in the example of FIGs. 1-5, as illustrated in FIGs. 3-4. As explained below in more detail, the pivot joint allows an increased angular range, and thus allows a larger angle of misalignment of the elements of the water transport system to be connected via the joint. Advantageously, but not necessarily, the increased angular range can be obtained without increase in the size of the joint.

Through the pivot joint 4, a liquid-tight liquid flow passage 41 is, or can be established between an inside of a first transport element and the inside of a second transport element, e.g. in the example of FIGs. 1-5 between the channel 23 in the manhole and the inside of a pipe 3, which are pivotably connected to each other. As can be seen in FIGs. 3 and 4, for instance, the pipe 3 is attached to the second pivot member 6 in that example, and the first pivot member 5 to the manhole 1 to be able to transport foul or rain water from or to the manhole through the pivot joint 4.

The pivot joint 1 has a first element side 42 and a second element side 43, and at the respective side is connectable (and in the example of FIG. 1-5 is connected) to a transport element, such as a pipe or other element of the transport system. Each of the pivot joints 4,4' comprises two pivotable members 5,6. In this example liquid tight, passage 41 extends from the first element side 42 to the second element side 43 through the first pivot member 5 and the second pivot member 6.

In FIGs. 3 and 4, the pipe 3 is admitted in a socket shaped opening of the second pivot member 6 in which the pipe 3 has been inserted in a direction of insertion. In this example, the direction of insertion is from the exterior of the manhole base 2 towards the interior thereof and parallel to the flow direction 40, more specifically in the same direction as the flow direction 40 for an upstream pivot joint 4 and opposite to the flow direction 40 for a downstream pivot joint 4'. The pipe 3 is thus pivotable relative to the first pivot member 5, by a suitable pivoting of the second pivot member 6 relative to the first pivot member 5. Depending on the intended application, the first pivot member 5 and the second pivot member 6 may be implemented differently e.g. to be attached to, or to admit, other elements of a water transport system, other than respectively a manhole base and a pipe.

In FIGs. 3 and 4, the first pivot member 5 is attached to the respective port 24 at the first element side 42 of the pivot joint 4 but as illustrated in FIGs.16 and 17 for example the first pivot member 5 may be attached to another element of a water transport system instead. The first pivot member 5 is fixated relative to the port 24 and can be an integral part seamlessly connected to the wall 21, or be a separate part that has been mounted into the port 24. The second pivot member 6 is pivotably attached to the first pivot member 5 and, as is explained in more detail with reference to FIGs.6-15, pivotable relative to the first pivot member 5 around a pivot axis extending through a pivot point P in a direction of rotation t. To the second member 6 a second element can be attached at a second element side 43 of the pivot joint 4.

The first pivot member 5 comprises a first passage PL, extending between the first element side 42 and a second element side end of the first pivot member. The first passage PL passes in axial direction a through the smaller cage space 50 described below in more detail. The second pivot member 6 comprises a second passage Ps extending through the second pivot member 6 between a first element side end of the second pivot member 6 and a second element side end of the second pivot member 6. The first and second passage PL,PS are in liquid (but alternatively may be in fluid) communication, such that the passage 41 extends from an opening, at a first element side 42 of the pivot joint, of the first passage PL to an opening, at the second element side 43, of the second passage Ps. In operation of the pivot joint, for example a liquid flow, e.g. water such as waste or drainage water may flow at the bottom part of the passages PL and Ps. Preferably but not necessarily, the liquid flow in the transport system is laminar, and the bottom part of the passages PL and Ps as well as the transition between them such that there is no turbulence induced when the liquid flows through the joint. ln this example, the first passage PL is a first, larger passage, of which the wall 57 is indicated with the thickened line in FIG. 8, which extends through the first pivot member 5 from the first element side 42 up to the second element side 43. In the first passage, the second pivot member 6 is admitted, in this example with a first element side part thereof while a second element side part of the second pivot member 6 projects out of the passage P _L at the second element side 43. More specific, in this example, in the first passage P _L a free-end of the second pivot member 6 can be admitted from the second element side 43. At the free end, an inner rotatable part and an outer rotatable part of the second pivot member 6 are located, as explained below in more detail.

The first passage P _L is reduced in inner diameter by the second pivot member 6 admitted therein. More specifically, as more clearly shown in FIG. 8, the second pivot member 6 is provided with a second, smaller passage P _s (of which the wall 67 is indicated with the thickened line in FIG. 8) with an inner diameter άi smaller than the inner diameter di of the first passage. As shown, the outer diameter of the second pivot member 6 is locally smaller than the inner diameter of the larger passage P _L and an interstitial space 45 is formed between the two members 5,6.

At the contact area, where the outside of the second pivot member 6 contacts the wall 57, the second pivot member 6 has an outer diameter which is equal to the inner diameter of the wall 57 of the first passage PL. More specifically in this example the contact area is located at the first element side end 61 of the second passage Ps where the inner rotatable part 60 contacts the smaller cage 50. At the first element side 42, the first element side end 61 thus closes off the interstitial space 45 between the outer wall of the second pivot member 6 and the larger passage. As explained in more detail further below, the second pivot member 6 provides a liquid tight wall to the passage. In this respect the first element side end 61 may be implemented as a liquid barrier which inhibits liquid from seeping into the space 45 between the outside of the second pivot member and the larger passage PL. For example, the first element side end 61 may be shaped as a flexible lip which is slightly resiliently pushed inwards, towards the axis a, and thus in operation presses onto the wall of the first passage P _L to provide a closing contact between the first element side end 61 and the wall 57, with the closure in this example being between the running surface 54 and the contact surface 600 of the rotatable part 60. This contact may be a sealing contact, i.e. a liquid tight closure, or allow some liquid to seep in to the space 45. The space 45 between the outside of the second pivot member and the larger passage P _L is sealed off by a sealing 66 therebetween, which seals the second element side 43 from any liquid passing via the space 45 to that side 42. The sealing 66 is located, seen in the direction from the first element side 42 to the second element side 43 beyond the first element side end 61 of the second pivot member 6, and in this example in the larger cage 52 of the first pivot member. In case the first element side end 61 and the wall of the larger passage do not make a liquid-tight seal, the sealing 66 prevents liquid seeping between the edge 61 and the wall of the larger passage into the space from leaking out of the pivot joint at the second element side 43, and thus allows to improve the leak resistance of the pivot joint.

The pivot joint 4 allows to pivot the first element relative to the second element, or vice versa, as follows. The first pivot member 5 defines a pivot point P around which the second pivot member 6 can be pivoted relative to the first pivot member 5 (or vice versa of course), and accordingly the transport elements when the first transport element is attached to the first pivot member 5 and the second transport element to the second pivot member 6. In the shown example, the base 2 will typically be stationary relative to its environment while the pipe 3 is moved relative to the base 2 and to the environment but for other types of elements, the first element and/or the second element may be pivotably moved relative to the environment.

The first pivot member 5, as shown, comprises a larger cage 52 and a smaller cage 50, each defining a pivot point P for a respective rotatable part 60,62 of the second pivot member 6 mated with the respective cage 50,52. In this example, the smaller cage 50 and the larger cage 52 are co axially arranged and the pivot point P of the smaller cage 50 coincides with the pivot point of the larger cage 52. Alternatively, the smaller cage 50 and the larger cage 52 may be arranged eccentrically and their pivot points P for example offset, in the axial direction a and/or radial direction r, such as by a couple of millimetres, such as 1,2, 3, 4 or 5 mm. The pivot points P lay in the example on the axis 44 through the centre of the respective cage 50,52, but alternatively one or both of the pivot points may be offset in the radial direction r from the axis. Each of the cages 50,52 has a cage space in which a respective rotatable part 60,62 of the second pivot member 6 is confined. The cage space is delimited by an inner surface 54,56 which forms a, curved, running surface over which a contact surface 600,620 of the rotatable part 60,62 is rotationally movable, around the pivot point P, in a direction of rotation from the second element side 43 towards the first element side 42, or vice versa, as is illustrated in FIGs. 10-15 and as indicated with arrow t. The curvature of the running surface in the direction of rotation, i.e. the tangential direction t in these figures, defines the pivot point P of the cage.

In the shown examples, the axis of the respective rotatable part 60,62 coincides with the axis of the cage 50,52 in which the rotatable part 60,62 is confined, in a neutral position where the axis are parallel. Alternatively, for one or both rotatable part 60,62 the axis may be offset in the radial direction r from the axis of the respective cage.

In the examples, the smaller running surface 54 extends between a first element side edge 500 and a second element side edge 502 whereas the larger running surface 56 extends between a first element side edge 510 and a second element side edge 512. The smaller cage 50 is delimited by the smaller running surface 54 in this example and is closed in the radial direction while open at the axial sides, i.e. at the first element side edge 500 and the second element side edge 502. The larger cage 52 is delimited by the larger running surface 56 in this example and is closed in the radial direction while open at the axial sides, i.e. at the first element side edge 510 and a second element side edge 512.

As shown in FIG. 7, the smaller cage 50 has a smaller running surface 54 and the larger cage 52 has a larger running surface 56, the terms "smaller" and "larger" defined here as the distance from the pivot point P. The smaller running surface 54 has a sharper curvature in the direction of rotation t than the larger running surface 56, and the larger running surface 56 projects in a tangential direction t beyond a second pivot member side edge 502 of the smaller running surface 54.

Thereby, a larger range over which the first and second pivot member 5,6 can be pivoted can be obtained without need to increase the overall size and dimensions of the pivot joint. Thus, compared to the prior art pivot joint known from EP 1141495 referred to in the section "Background of the invention", the maximum angle of misalignment between the elements 2,3 of the transport system, can be increased while maintaining a relatively compact pivot joint.

Because the larger running surface 56 projects in a tangential direction t beyond the second pivot member side edge 502, the large running surface has a part which extends from the second pivot member side edge 502 towards the first element side 43 as well as a part which extends from the second pivot member side edge 502 towards the second element side 43. Thus, the larger running surface 56 and the smaller running surface 54 do not completely overlap in the tangential direction but at least the second pivot member side edges 502,512 are off-set in that direction. In the shown example, the first pivot member side edges 500,510 are off-set as well.

In this example, each of the running surfaces 54,56 has a non-overlapping part. Said differently, the partial overlap is such that the smaller running surface 54 projects in the direction opposite to the direction in which the larger running surface 56 projects, in this example beyond the first pivot member side edge 510 of the larger running surface 56. The smaller running surface 54 has a non-overlapping part extending from the first pivot member side edge 510 towards the first element side 43. Described in a more mathematical manner, for the large running surface 56 the first element side edge 510 lies in the tangential direction t at an angular position a and the second element side edge 512 at an angular position b, whereas for the smaller running surface 54 the first element side edge 500 lies at an angular position y and the second element side edge 502 at an angular position d, which are related as follows: a < d < b (1) g < a < d (2)

As a result, the running surfaces have an overlap in the tangential direction from a to d. The combined running surfaces extend in the tangential direction from g to b, while each of the running surfaces 54,56 extends over a shorter angular distance.

As a result of the partial overlap in the tangential direction t, as can be seen in e.g. FIG. 7, the running surfaces 54,56 are off-set in the axial direction as well, with in this example a partial overlap. More in detail, the first element side edge 510 of the larger running surface 56 is located at the first first element side of the second element side edge 502 of the smaller running surface 54, and the second element side edge 512 of the larger running surface 56 is located at the second first element side of the second element side edge 502 of the smaller running surface 54. The larger running surface 56 thus projects beyond the second element side edge 502 of the smaller running surface 54 in the axial direction from the second element side to the first element side. Vice-versa, the second element side edge 502 of the smaller running surface 54 is located at the first element side of the second element side edge 512 of the larger running surface 56, and the smaller running surface 54 projects beyond the first element side edge 502 of the larger running surface 56 in the opposite axial direction.

As shown, the cages 50,52 may be off-set in the axial direction. In this example, there is a partial overlap in the axial direction. The smaller cage 50 is partially admitted in the larger cage 52 and projects at the first element side 42 out of the larger cage 52. Vice-versa, in this example the larger cage 52 extends, in the axial direction towards the second element side 43, beyond the part of the smaller cage 50 admitted in the larger cage 52 and thus projects in that direction relative to the smaller cage 50.

In this example, as can be seen in FIG. 7, the wall of the larger cage 52 defining the larger running surface 56 projects, both in the tangential and axial direction from the second element side 43 to the first element side 42, beyond the second pivot member side edge 502. At the first element side edge 510 of the larger running surface 56, the larger cage 52 is connected to the outer wall of the smaller cage 50. The smaller cage 50 extends into the larger cage 52 and the wall of the smaller cage 50 with the smaller running surface 54 projects, in this example partly, into the space of the larger cage 52. Thus, between the first element side edge 510 of the larger running surface 56 and the second element side edge 502 of the smaller running surface 54 a recess is formed in which a first element side part, hereinafter referred to as the front part, of the rotatable part 62 of the second pivot member 6 mated with the larger cage 52 can be admitted. Thus, the range over which the front part can rotate is increased, without, or at least a limited, increase of the overall thickness of the pivot joint. Similarly, the projection formed by the part of cage wall on which the smaller running surface 54 extends, projects into the space of the larger cage 52, which allows to move the front part of the rotatable part 60 of the second pivot member 6 mated with the smaller cage 50 over a larger angle without, or at least a limited, increase of the overall thickness of the pivot joint 4.

As shown, in this example, the first element side edge 510 projects out of the larger cage 52 at the first element side 42. The first element side edge 510 of the larger running surface 56 is, seen in the axial direction a, located between the first element side edge 500 and the second element side edge 502 of the smaller running surface 54, and the part of the smaller cage 50 between the first element side edge 500.

In the shown example, the cages 50,52 form a housing for the first element side part of the second pivot member 6, i.e. the part admitted and confined into the cages 50,52, which except for the entrance or opening of the larger passage PL is liquid tight. As best seen in FIGs. 7 and 9, the annular gap between the outside of the smaller cage 50 and the inside of the larger cages 52 is completely closed off at the edge 510, here by a flange 53 which extends in the radial direction and which, in this example, is integrally formed with the cages 50,52. This provides not only a liquid tight closure of the gap, but also a stop for the outer rotatable part 62 at the edge 510, and thus defines the maximum angle of rotation. In the example the maximum angle of rotation is the same for any direction of rotation around the pivot point but, depending on the specific implementation, the angle may vary, and the maximum angle be different for different directions of rotation. For example, at the bottom side in FIG. 7, the gap may be less deep than at the top side, such that the maximum angle is different for a clock-wise rotation compared to counter clock wise rotation.

As best seen in FIGs. 6,11,13 and 15, in the shown examples the running surfaces 54,56 of the cages 50,52 and the rotable parts 60,62 of the second pivot member 6 are circular in cross- section (perpendicular to the axial direction, and in the plane of the radial direction) and accordingly the rotational characteristics are the same, independent of the orientation of the pivot axis. Flowever, it will be apparent that the rotational characteristics may be dependent on the orientation of the pivot axis and e.g. the running surfaces 54,56 of the cages 50,52 and the rotable parts 60,62 may be shaped as elliptical, stadium or other rounded rectangle, seen in this cross- section.

In the shown example, both the running surfaces 54,56 and the rotatable parts 60,62 are, continuous, loops closed in the circumferential direction c. Accordingly, the orientation of the pivot axis can be freely chosen over the entire, and continuous, range of 360 degrees around the axial direction. Alternatively, the running surfaces 54,56 and the rotatable parts 60,62 can e.g. be open loops or interrupted in the circumferential direction and the orientation of the pivot axis be limited. Thus, one, two or more than two, and preferably all, of: the smaller running surface, the larger running surface, the inner contact surface, and the outer contact surface, can be an uninterrupted ring or band. Alternatively, one, two or more than two of: the smaller running surface, the larger running surface, the inner contact surface, the outer contact surface can be interrupted in tangential direction. For instance, as illustrated in FIG. 24, the inner rotatable part 60 may be interrupted by slots 69 extending in the axial direction. This allows increase the flexibility of the part in the radial direction r, and e.g. to resiliently compress the inner rotatable part 60 when admitted into the smaller cage 50 by a pressure exerted by the smaller running surface 54.

Generally speaking, the running surfaces 54,56 may have any suitable shape, curvature and diameter, e.g. as illustrated in FIG.21 where they have a stepped profile, and as illustrated in FIG. 22 where the smaller running surface 54 differs in shape from the larger running surface 56 and has a ribbed profile. In the example of FIGs. 6-15, though, the running surfaces have the same shape and are frusto-ellipoids. One or, as in the examples, all of the frusto-ellipsoids can be a spherical zone, of a sphere with a radius corresponding to the desired rotational path of the rotatable part 60,62. In FIGs. 6-15, the inner surface of the smaller cage 50 is a spherical zone of a sphere with a radius smaller than a sphere of the spherical zone of the inner surface of the larger cage 52. The centre of both the spheres coincides and are located at the pivot point P.

The second pivot member 6 comprises an inner rotatable part 60 confined in the smaller cage 50 and an outer rotatable part confined 62 in the larger cage 52. Both rotatable parts 60,62 are located at a first element side of the second pivot member 6. A contact surface 600 of the inner rotatable part 60 is movable over the smaller running surface 54. A contact surface 620 of the outer rotatable part 62 is movable over the larger running surface 56. The contact surfaces 600,620 are located at the free-end of the second pivot member 6 and form the axial end of the second member in the respective cage. The contact surface 600 of the inner rotatable part 60 is located closer to the pivot point than the contact surface 620 of the outer rotatable part 62. As shown, the rotatable parts 60,62 project in the axial direction a from the free-end of the second pivot member 6 towards the first element side 42. The outer rotatable part 62 is in this example located in the axial direction further away from the first element side 42 than the inner rotatable part 60. As shown, in radial direction between the contact surfaces 600,620 a recess is present in which the part of the smaller running surface 54 projecting into the large cage 52 can be admitted.

In the shown example, seen in the tangential direction the contact surfaces 600,620 are located at different angular positions and extend in the tangential direction over a range Deoo, D62o· In this example the difference is more or less the same as the off-set of the contact surfaces 54,56. This can be described in a more mathematical manner as follows. Assuming that Deoo, De2o are very small compared to the respective angular distance (b-a ; d- y) over which the running surfaces extend and can be ignored, in the examples when the contact surface 600 of the inner rotatable part 60 lies between y and d, such that it contacts the smaller running surface 54, the contact surface 620 of the outer rotatable part 62 lies between a and b, such that it contacts the larger running surface 56. The angular distance e between the contact surfaces 600,620 can be about the same as the smallest of a - y and b- d (which in this example are equal but may be different depending on the angular position of the edges 500,502,510,512).

The contact surfaces 600,620 are off-set in the axial direction as well. More in detail, the contact surface 600 of the inner rotatable part 60 is, when the pivot joint is in the neutral position, located closer to the first element side 42 than the contact surface 620 of the outer rotatable part 62. In this position, the contact surface 600 contacts the smaller running surface 54 more or less in the middle of the running surface 54, and the contact surface 620 contacts the larger running surface 56 more or less in the middle of the running surface 56.

In the shown example, the second pivot member 6 has an opening in which the second element, e.g. the pipe 3, can be admitted. The inner rotatable part 60 forms the wall of the second flow passage Ps in the part between the first flow passage PL and the second element, and thus serves in operation as a first element side extension of the second element. The second pivot member 6 can be seen as a sleeve which encloses the end of the second element. The inner wall of the sleeve defines the opening. In this example the inner rotatable part 60 projects in axial direction from the inner wall and bridges the gap between the sleeve and the first flow passage PL and contacts the smaller running surface 54. The outer wall of the sleeve forms the outer rotatable part 62. In the radial direction r, the outer rotatable part 62 projects to bridge the gap between the sleeve and the housing formed by the larger cage, and the contact surface 620 contacts the larger running surface 54. As shown, the outer rotatable part 62 lies in the axial direction further away from the first element side 42 than the inner rotatable part 60.

Although various shapes are possible, such as finger shaped, cylinder segmented etc, as best seen in FIG. 7, in this example the inner rotatable part 60 comprises an inner rim abutting to the smaller running surface 54. The outer rotatable part 62 comprises an outer rim abutting to the larger running surface 56.

The contact surface 600 of the inner rotatable part 60 lies, in a direction of insertion of the second element 6, closer to the first element side end 42 than the contact surface 620 of the outer rotatable part 62. A first element side end of the smaller running surface 600 projects in a direction of insertion of the second element beyond a first element side end 510 of the larger running surface 56. Between the projecting part and the larger running surface, a recess is formed in which the outer rotatable part 62 can be admitted. As shown, a space 45 delimited by the housing (formed by the cages 50,52), the rims and the groove is thus present between the first pivot member and the second pivot member.

As can e.g. be seen in FIG. 7, the inner rim and outer rim are in this example annular and separated by an annular groove. The annular inner rim and outer rim project in the axial direction towards the first element side 42, and in the groove the, equally annular in this example, projecting part of the smaller running surface 54 can be admitted. As can be seen in FIGs. 12 and 14 for instance, in this example, when the second pivot member 6 is pivoted to a maximum angle relative to the first pivot member 5, the second element side end 502 of the smaller running surface 50 at the side of the pivot axis is moved by the rotation to the second element side 43 and admitted into this annular groove. This allows to increase the maximum angle without being required to increase thethickness (i.e. the size in the axial direction) of the pivot joint 4. The bottom of the groove serves in this example as a stop for the rotation and when the second pivot member 6 is rotated to the maximum of the angular range the projecting part of the smaller cage 50 abuts to the bottom. In this example, at the same time, the outer rotatable part 62 will abut to the flange and the pivot joint thus has two stops operate simultaneously, but it will be apparent that e.g. the annular groove may be deeper than the annular recess or vice versa. In such a case, the shallowest one of the two will define the maximum angle and operate as a stop.

One, or both, of the contact surfaces can be shaped to conform to the running surface. In the examples, for instance, the contact surface 600 is curved with the same curvature of the running surface it contacts, whereas the contact surface 620 comprises a deformable ring 66 which conforms to the curvature of the larger running surface 56. This allows a smooth sliding of the surfaces upon rotation of the second pivot member or the first pivot member relative to the other.

In the examples, the running surfaces 54,56 taper from the second element side 43 towards the first element side 42. More specifically, the diameter in the radial direction of the running surface 54,56 at the respective second element side edge 502,512 is larger than the outer diameter of the respective rotating part 54,56 whereas the diameter in the radial direction of the running surface 54,56 at the respective first element side edge 500,510 is smaller than this outer diameter. Thus, the second pivot member 6 (or more precisely the rotating part admitted in the cage) cannot pass through the cages and accordingly is form closed by the cages in that direction.

At the second element side 43, the second pivot member 6 can be locked by a form closure as well, to inhibit or block the rotatable parts 60,62 from slipping out of the cages 50,52. To that end, in the shown example, the pivot joint 4 comprises an inwards projecting profile 46 located, seen in the axial direction a, between the second element side end 43 and the larger running surface 56. In this example the inwards projecting profile 46 is shaped as a locking ring, but other shapes are likewise possible. The locking ring is, as more clearly seen in FIG. 25 b and c, placed on the, equally ring shaped, second element side of the larger cage 52, and projects radially inwards relative to the edge 512.

The inwards projecting profile 46 limits rotation of the outer contact surface 620 beyond the second element side edge 512 of the larger running surface 56. More specific, the second pivot member 6 has a curved outside surface 64 which is curved in the direction from the second element side 43 to the first element side 42. The larger pivot cage 52 is provided with the inwards projecting profile 46 which is located between the second element side end and the larger running surface. The curved outside surface 64 contacts the inwards projecting profile, and accordingly in case of pivoting of the second pivot member 6, the curved outside surface 64 rotationally slides over the inwards projecting profile 46. This increases the contact surfaces which transfer forces between the larger cage 52 and the outer rotatable part, and thereby ensures that even over a larger angle the cage 52 effectively supports the second pivot member 6.

In this example, the curvature of the curved outside surface 64 has a radius equal to the distance between the inwards projecting profile and the pivot point P, and accordingly upon rotation the curved outside surface 64 remains in contact with the inwards projecting profile 46. As indicated in FIG. 23 for the kit from which this example can be implemented, the radius is smaller than the radius of the curvature of the larger running surface 56 and may, as in this example, be larger than the radius of the curvature if the smaller running surface.

As can be seen in FIG. 10, when the second pivot member 6 and the first pivot member 5 are not pivoted, the outer contact surface 620 projects in the radial direction beyond the curved outside surface 64 and in that direction has a larger outer diameter than the inner diameter of the inwards projecting profile 46. Thus, the outer contact surface 620 is locked by the inwards projecting profile 46 in the larger cage 52 against forces in the axial direction a. In addition, in this example the curved outside surface 64 has a larger outside diameter than the inner diameter of the inwards projecting profile 46, and according is locked as well. Seen in the rotational radial direction, i.e. the direction from the pivot point P to the respective part, the outer contact surface 620 has a larger outer diameter than the inner diameter of the inwards projecting profile 46 as well, i.e. the distance from the outer contact surface to the pivot point P is larger than the distance from the inwards projecting end of the inwards projecting profile 46 to the pivot point. Thus, when the second pivot member 6 is pivoted to the maximum angle of the angular range with the outer contact surface 620 moving towards the side 42, and hence towards the inwards projecting profile 46, the profile will act as a stop for the outer contact surface 620. The stop blocks further pivoting beyond the maximum angle. More specific, the outer contact surface 620 will, as e.g. shown FIG. 12 at the bottom side, come to contact the side of the inwards projecting profile 46 extending in the radial direction r. The inwards projecting profile 46 will thus block the further pivoting of the outer contact surface 620, as illustrated in FIGs. 12 and 14 where the bottom, respectively top, part of the contact surface 620 is blocked. The inwards projecting profile 46 thus also limits the angle of rotation. As illustrated in FIGs. 12 and 14, the curved outside surface 64 has the same or a smaller diameter in the rotational radial direction and can slide over the profile 46, to project out of the large cage 52 at the second element side 43 upon maximum rotation of the second pivot member 6.

In this example, the curved outside surface 64 is a profiled surface with radially outwards projecting ribs 640 which in the tangential direction t are spaced from each other and which extend in the circumferential direction around the outside of the second pivot member 6. In this example, the ribs 640 are formed as annular protrusions from the second pivot member 6. Thus, when pivoting the second pivot member 6 around the pivot axis, the ribs will slide over the inwards projecting profile 46 and due to the successive ribs and gaps a, e.g. for humans perceptible feedback, e.g. haptic and/or auditive, about the amount of rotation is provided to a human operator. As best seen in FIG. 24, the annular protrusions are continuous in the circumferential direction. Thereby, when rotating the ribs will contact the inwards projecting profile 46 over substantially the entire circumference and excessive contact pressures can be avoided.

In this example, the inwards projecting profile 46 has a curved contact surface, curved in the tangential direction with the same curvature as the curved outside surface 64. This provides a smooth sliding of the two surfaces when rotating and further provides a good support by the inwards projecting profile 46 of the second pivot member 6 which allows to avoid excessive contact pressures.

As mentioned above, the pivot joint 4 may comprise a sealing. In the shown example, the pivot joint 4 comprises a sealing in the form of a sealing ring 66 between the outer contact surface 620 and the larger running surface 56, which liquid-tight seals-off a first element side 42 of the first pivot member 5 from the second element side 43. Thus, any liquid passing through the pivot joint 4 between the sides 42,43 passes through the second pivot member 6. The sealing ring 66 is placed in a circumferential groove 68 in the outer contact surface 620, and thereby held in position in the axial direction. The ring 66 is in this example resiliently compressed between the outer contact surface 620 and the larger running surface 56. As illustrated, the sealing ring 66 slides with the rotating of the second pivot member 6 over the larger running surface 56 and maintains a sealing contact between the cage and the outer rotating part 62.

Referring to FIGs. 10-15, the pivot joint may operate as follows. In FIG. 10, the pivot joint is shown in a neutral position with the angle between the members 5,6 being in the middle of the angular range over which they can be pivoted relative to each other. In this example, the members 5,6, are in the neutral position oriented with their axis in parallel and coinciding. Furthermore, the outer rotatable part is in this example in the neutral position outside the recess between the smaller and larger running surface, and the projecting part of the smaller cage is outside the groove. As seen in FIG. 11, in this position, in this example the circular annular parts are oriented co-axially, with their axis 44 in parallel. In FIGs. 12-13 and FIGs. 14-15 the pivot joint is shown in a pivoted position, with the members 5,6 at an angle and rotated in a first direction and a second, opposite direction. In the shown example, in this state the axis 44 of the first pivot member 5 is at a non zero angle relative to the axis 44 of the second pivot member 6, and in this example their axis 44 cross-each other at the pivot point P.

In this example, the pivot joint has two rotational degrees of freedom, and more specific the pivot joint can be pivoted around a pivot axis extending in the radial direction of which the orientation can be chosen. The position of the pivot axis is fixed in that the pivot point is fixed and the pivot axis extends through this point, regardless of the orientation of the pivot axis. Depending on the specific implementation the pivot joint may have a third rotational degree of freedom, and the first pivot member 5 or the second pivot member 6 be rotatable relative to the other member around an axis extending parallel, and optionally coinciding, with the axial direction a. Although in other implementations this may be different, in the present examples, the pivot joint does not have translational degrees of freedom.

When pivoting, the orientation of the pivot axis may be set. It will be apparent that in the following the directions and orientations of the various depend on the orientation of the pivot axis and accordingly with a different orientation may vary (e.g. when instead of a horizontal pivot axis, the pivot axis is set vertically the directions and orientations change correspondingly).

When the second pivot member 6 is rotated relative to the first pivot member (or vice versa) the contact surfaces 600,620 will make a rotational movement around the pivot point P, along and guided by respective the running surface 54,56. Said differently, each rotatable part 60,62 will pivot in the cage 50,52 in which the part is confined and with which the part is mated, along the trajectory defined by the curvature of the running surface 54,56 in the direction of rotation, e.g. in the examples in the tangential direction t . As illustrated in FIG. 12 and 13, if for example the second pivot member 6 is pivoted counter clockwise, around a horizontal pivot axis, at the upper halve of the joint, the outer rotatable part will rotationally move towards first element side 42, with the edge 510 determining the range of rotation. The inner rotatable part will rotationally move towards the first element side 42, with the edge 500 determining the range of rotation. At the bottom halve, the outer rotatable part will rotationally move towards the edge 512, whereas the inner rotatable part will rotationally move towards the edge 502. At the bottom halve, those edges 502,512 determine the range of rotation. If, the maximum angle is reached, the stop at the first element side 42 (formed in this example by the bottom of the annular groove and the annular recess) will stop the outer rotatable part, and the stop at the second element side 43 will stop the outer rotatable part at the bottom. As shown, the outer rotatable part has in this pivoted position become admitted in the recess between the smaller and larger running surface, and the projecting part of the smaller cage has become admitted in the groove between the inner and outer rotatable parts.

Figs. 14 and 15 illustrate a rotation in the opposite direction, i.e. clockwise. As shown, in such a case the top of the rotatable part will rotationally move to the second element side 43, while the bottom part will rotationally move towards the first element side 42.

As can be seen in FIGs. 14-15, in this example, the curved outside surface 64 is always contacting the inwards projecting profile 46 and thus supported thereby over the entire angular range of rotation. As shown,, when the part moving to the second element side 43 is closest to the second element side 43, and in this example stopped by the inwards projecting profile 46, the rib 640 in tangential direction closest to the outer rotatable part 62 is supported by the profile, whereas when the part moving to the first element side 42 is the most remote from the second element side 43, the rib 64 in tangential direction most away from the outer rotatable part 62 is supported by the inwards projecting profile 46. Thus, over the entire range of rotation the second pivot member 6 is always supported in at least two locations by the larger cage: at the contact surface 620 and the part of the curved outside surface 64 contacting the inwards projecting profile 46.

As illustrated in FIGs. 16 and 17, the pivot joint 4 may be shaped to connect e.g. pipes 3,3', or as illustrated in FIG.1-6 to connect a pipe to a manhole or for any other type of element. Likewise, as illustrated in FIGs. 18-20, the sides 42,43 may be shaped as a connector compatible and connectable to a predetermined type of element. In the example of FIGs. 18-20, the first element side is shaped to be part of a wall of e.g. a manhole or other separation and suitable to be mounted in or be manufactured as an integral part of a port in the wall, e.g. by welding, gluing etc. as explained above with reference to FIGs. 1-6. The other side 42 is provided in these examples with a connector compatible and connectable to a pipe, and more specific, the second pivot member 6 is provided with the connector, which allows to connect the passage 41 to the pipe 3. In FIG. 18, the connector 48 is a socket adapter into which a pipe with a compatible spigot can be inserted. In FIG. 19, the connector 48 is an adaptor compatible and connectable to a structured wall pipe. In FIG. 20, the connector 48 is a spigot adapter over which a pipe with a compatible socket can be placed.

The pivot joint may be provided in an assembled state. Alternatively, as illustrated in FIG. 23 and 24, the parts may be provided as a kit of parts, which can be assembled into a pivot joint. Such a kit may comprise the first pivot member 5 and the second pivot member 6 in one of: a connected state, also referred to as assembled state, or an unconnected state, also referred to as a unassembled state. It will be apparent that the kit may comprise other parts as well, such as the sealing ring 66 or the inwards projecting member 46.

The kit may e.g. contain all parts of the pivot joint or, e.g. in case one of the pivot members is provided as an integral part (such as integrally moulded in the same shot as the manhole) at least one of the pivot members and, optionally other parts of the pivot joint. In the example of FIGs. 23 and 24, for instance, the kit contains the first pivot member 5, the second pivot member 6, the sealing ring 66 and the inwards projecting profile 46.

As illustrated in FIG. 25, the kit can be assembled into a pivot joint by mating the parts 60,62 with the respective cage 50,52. As illustrated in FIG. 25 a, if present, the sealing ring 66 may have been provided on the outer surface of the second pivot member 6, such that the sealing ring 66 seals off the space between the outer contact surface 620 and the larger running surface 56 when the rotatable outer part 62 is placed in the larger cage space. In the example of FIG. 25, for instance, the sealing ring 66 may be placed in a circumferential groove 68 (shown in FIGs. 23-24) and slightly projects beyond the outer diameter of the second pivot member 6. When the outer rotatable part 62 is placed in the larger cage 52, the sealing ring 66 is (elastically) compressed between the larger running surface and the groove and hence seals off any passage between them.

Simultaneously or thereafter, the rotatable parts 60,62 may be placed in the respective cage 50,52 (as illustrated in b). For example, they may be placed with the respective contact surface 600,620 contacting the running surface 54,56 of the cage, e.g. by inserting the rotatable parts 60,62 in the cages spaces from the second element side 43 until the contact surfaces abut to the respective running surface.

As illustrated in FIG. 25c, after mating the rotatable parts 60,62 and the cages 50,52 the inwards projecting profile 46 may be attached to the first pivot member 5 to confine the rotatable parts in their cages 50,52. In this example, the inwards projecting profile 46 is placed against the second pivot member side edge of the housing formed by the larger cage 52 and the smaller cage 50. Due to its radially inwards projection, the profile 46 form-closes the confined part of the second pivot member 6 in the first pivot member 5 in the direction from the first element side 42 to the second element side 43, while the tapered shape of the cages 50,52 form-closes the confined part of the second pivot member 6 in the opposite direction in the cage.

Referring to FIG.26, the example of a pivot joint may be used in the manhole shown in FIGs. 1-6 but likewise be used in other parts of a water transport system, such as to pivotably connect two pipes 3 or other elements of the water transport system to each other. As illustrated in FIG. 26, for example the pivot joint may be used in a water transport system to connect a pipe to a manhole or other type of underground chamber, to connect two pipes to each other and generally to pivotably connect two elements of the water transport system to each other, and to establish through the pivot joint a liquid-tight liquid channel between an inside of the first element and the second element.

Referring to FIG. 26, as an example of a fluid transport system in which the pivot joint 4 may be used a part of a foul or rain water transport system 100 is shown. As shown, the system may comprise at least two transport elements, such as manholes 1 and pipes 3, and one or more pivot joints 4 of which the first pivot member is connected at the first element side to a first element of the elements and the second pivot member connected at the second element side to a second element of the transport elements. The system thus has a liquid-tight liquid channel between an inside of the first element and the second element, extending through the pivot joint. The first element can e.g. be a manhole, such as described above and the second element can be a pipe, as shown. FIG. 26 further shows a T-shaped connector 13 connected to pipes 3 via pivot joints of the described type. Instead of a water transport system, the fluid transport system may alternatively be implemented as e.g. a gas transport system. The fluid transport system may be a public utility system to deliver or discharge liquids and/or gasses from buildings, for example.

The system 100 can e.g. be manufactured with a method of manufacturing a foul water system, as follows. Initially, at least two water transport elements 1,3 may be placed in a desired orientation and position on or in the ground. The water transport elements may then be connected with a pivot joint 3, such as described above. For example, the first pivot member 5 may at the first element side 42be connected to a first element of the elements and the second pivot member 6 be connected at the second element side 43 to a second element of the elements. Because of the pivot joint 4, the elements 1,3 do not need to be exactly aligned to the ideal or intended alignment but some margin of mis-alignment of the orientation is allowed and can be corrected for by pivoting of the pivot joint 4. A liquid-tight liquid channel extending through the pivot joint may thereby or thereafter be established between an inside of the first element and the second element. Thus, water can flow through the joint from the first element to the second element, of vice versa.

In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the broader scope of the invention as set forth in the appended claims.

For example, although in the shown example the pivot joint, pipes, manhole base, manhole cover are made of plastic, other materials may be used. Likewise, although in the examples a resiliently deformable sealing ring, e.g. of silicone or other material is used, other sealing between the running surfaces of the cages and the contact surfaces of the second pivot member may be suitable as well.

Furthermore, the pivot joint may be applied in other elements of a water transport system, such as for example a catch basin or other elements with a chamber through which water flows or which collects water.

Also, although in the example of FIGs. 1-5, the manhole shaft is a single element, the manhole (or other chamber-like element of a water transport system) may comprise multiple elements stacked on top of each other to provide an access from above ground to the bottom buried into the ground.

Furthermore, although in the example of FIGs. 1-5 the manhole base is shown with complete pivot joints, the manhole base may e.g. be provided one, two or more than two, first pivot members each connectable or connected to a separately provided second pivot member. For example, the first pivot members may have been integrally moulded into the manhole base (e.g. in the same shot as the circumferential wall 21), or have been mounted into the ports 24, e.g. by welding, gluing or otherwise to provide a passage from the inside of the manhole base, such as from the channel 23, to the exterior of the manhole base. The second pivot member may then be mated with first pivot member as described above with reference to FIG. 25 to obtain a pivot joint which provides a liquid tight passage through the pivot joint and to allow a second element of the water transport system, such as a pipe, to be pivotably attached to the manhole base via the pivot joint 1.

Also, although in the examples the pivot joint provides a liquid-tight passage, depending on the specific implementation the passage may be implemented as a fluid-tight passage or gas-tight passage. Also, in the shown example the fluid, i.e. water, is transported under atmospheric pressure, the pivot joint may be implemented to be suitable for pressurized fluids, such as drinking water or gas transport, for instance. Furthermore, instead of an upwardly open channel, alternatively an element with a closed channel may be used, for example a fitting such as a bend or otherwise. Also, the chamber may be a reservoir which (temporarily) stores the water, another liquid or a compatible type of fluid.

As another example, the curved outside surface 64 may instead of being provided with ribs be a smooth, unprofiled surface curved in a manner suitable to slide over the inwards projecting profile 46.

Moreover, the terms "front," "back," "top," "bottom," "over," "under" and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

However, other modifications, variations and alternatives are also possible. The specifications and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

The term "form-closed" refers to the German term "Formschluss", which is a connection between at least two connected elements formed by the interlocking shapes of the elements and in which the absence of a connecting force does not release the connection. In other words, in the case of a form-closed connection, the shapes of the connected elements are in the way of the other, such that the connection cannot be released without deforming the shapes. In the shown examples, the form-closure is permanent and cannot be released without destructively deforming the respective shapes.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of other elements or steps then those listed in a claim. Furthermore, the terms "a" or "an," as used herein, are defined as one or more than one. Also, the use of introductory phrases such as "at least one" and "one or more" in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an." The same holds true for the use of definite articles. Unless stated otherwise, terms such as "first" and "second" are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

1 manhole

2 manhole base

3,3' pipe

4,4' pivot joint

5,5' first pivot member

6,6' second pivot member

10 manhole shaft

11 manhole top

12 manhole bottom

13 connector

20 bottom

21 circumferential wall

22 bottom plate

23 channel

24 port

40 flow direction

41 passage

42 first element side

43 second element side

44 axis

45 space

46 inwards projecting profile

48 second element side opening

50 smaller cage

51 first element side end

52 larger cage

53 flange

54 smaller running surface 56 larger running surface

57 wall larger passage

60 inner rotatable part 61 first element side end

62 outer rotatable part 64 curved outside surface 66 sealing 67 wall smaller passage 68 circumferential groove

69 slots

100 water transport system

500 first pivot member side edge of the smaller running surface 502 second pivot member side edge of the smaller running surface

510 first pivot member side edge of the larger running surface

512 second pivot member side edge of the larger running surface 600 contact surface

620 contact surface

640 ribs