NL2016060B1

NL2016060B1 - Sewer spring.

Info

Publication number: NL2016060B1
Application number: NL2016060A
Authority: NL
Inventors: Ghazil Rachid
Original assignee: Rando Tools B V
Priority date: 2016-01-05
Filing date: 2016-01-05
Publication date: 2017-07-13

Abstract

The various aspects relate to a sewer spring for removing solid material from a tubing, the sewer spring comprising an elongated body having a substantially circular cross-section and comprising at least an organic thermoplastic polymer material and at least one protrusion provided around the body, spaced at regular distances along the central axis of the body. By using an organic thermoplastic polymer material, a lighter sewer spring is provided. And by virtue of characteristics of such organic thermoplastic polymer, the sewer spring may be manufactured having a central body, provided with at least one protrusion. Such protrusion is not necessarily a small protrusion; also a large or long protrusion may be provided. This allows for manufacturing of a reliable sewer spring. Furthermore, a male and female coupling are presented that may be provided at opposite ends of the sewer spring for connecting another spring or tools.

Description

Title: Sewer spring

Technical Held

The various aspects relate to a sewer spring and a coupling for a sewer spring.

Background

Sewer springs are provided for removing debris from sewer tubing. Sewer springs are provided as helical springs, manufactured out of steel wire. This allows the sewer springs to be flexible, which in turn allows them to more through bends in tubing in a relatively easy way. Sewer springs may be provided in segments that may be coupled using couplings. Steel springs are relatively heavy and for stainless steel to be sufficiently resistant to volatile substances that may be comprised by sewage, the bill of materials may be high.

Summary

It is preferred to have a sewer spring available that provides improved characteristics with respect to manufacturability and mechanical characteristics. A first aspect provides a sewer spring for removing solid material from a tubing, the sewer spring comprising an elongated body having a substantially circular cross-section and comprising at least an organic thermoplastic polymer material and at least one protrusion provided around the body, spaced at regular distances along the central axis of the body.

By using an organic thermoplastic polymer material, a lighter sewer spring is provided. And by virtue of characteristics of such organic thermoplastic polymer, the sewer spring may be manufactured having a central body, provided with at least one protrusion. Such protrusion is not necessarily a small protrusion; also a large or long protrusion may be provided. This allows for manufacturing of a reliable sewer spring.

In an embodiment, the protrusion is helically shaped. This allows for screwing of the sewer spring through debris. It should be noted that whereas a convention steel sewer spring comprises a helical wire as well, it cannot provided a screwing action as the wire forming the helix provides an outside perimeter that is flush, rather than having a profile.

In another embodiment, at least part of the protrusion is at least partially movable relative to the body parallel to the longitudinal axis of the body. Such protrusion allows for a certain spring action towards any debris, aiding in removing solids from tubing.

In a further embodiment, the protrusion is or the protrusions are integrally formed with the body. This provides more convenient manufacturing.

In yet another embodiment, the body comprises steel reinforcement, provided substantially at the central axis. This allows for a stronger sewer spring. A second aspect provides a female coupling device. A third aspect provides a male coupling device. A fourth aspect provides a coupling system for coupling a first sewer spring to a second sewer spring. A fifth aspect provides a sewer spring system.

Brief description of the drawings

The various aspects and embodiments thereof will now' be discussed in further detail. In the Figures,

Figure 1 A: shows a side view of a sewer spring;

Figure 1 B: shows a cross-section of a sewer spring;

Figure 2 A: shows a side view of a sewer spring;

Figure 2 B: shows cross-section of a sewer spring;

Figure 3 A: shows a side view of a sewer spring;

Figure 3 B: shows cross-section of a sewer spring;

Figure 4 A: shows a side view of a sewer spring;

Figure 4 B: shows cross-section of a sewer spring;

Figure 5 A: shows a side view of a sewer spring;

Figure 5 B: shows cross-section of a sewer spring;

Figure 6 A: shows a side view of a sewer spring;

Figure 6 B: shows cross-section of a sewer spring;

Figure 7 A: shows a side view of a sewer spring;

Figure 7 B: shows cross-section of a sewer spring;

Figure 7 C: shows a perspective view' of a sewer spring;

Figure 8 A: shows a side view of a sewer spring;

Figure 8 B: shows cross-section of a sewer spring;

Figure 9 A: shows a perspective view of a coupling for sewer springs;

Figure 9 B: shows a schematic top view- of a coupling for sewer springs;

Figure 10 A: show's a perspective cross-section of a coupling for sewer springs in locked state; and

Figure 10 B: shows a perspective cross-section of a coupling for sewer springs in unlocked state.

Detailed description

Figure 1 A shows a side view of a sewer spring 100 as a first embodiment of the first aspect. The sewer spring .1.00 shown in Figure 1 A has an elongated body 110 having a substantially circular cross-section and a protrusion 120. Within the definition of the elongated body 1.10 having a substantially circular cross-section is comprised that the cross-section of the elongated body 110 may, next to having a more or less exact circular shape, also be shaped as a polygon having obtuse angles. An example of such polygon may be a pentagon, a hexagon or an octagon.

The protrusion 120 comprises a continuous protrusion 120 having a helical shape and is provided around the body 110. Figure 1 B shows a cross-section of the sewer spring 100 over the central axis of the sewer spring 100. In this embodiment, the protrusion 120 follows a helical path such that the distance between the recurring ridge is about the same as the width of the protrusion 120 where the protrusion 120 protrudes from the body 110. The height of the protrusion is about half of the width of the protrusion 120 where the protrusion 120 protrudes from the body 110.

Figure 2 A shows a side view of a sewer spring 100 as a second embodiment of the first aspect. The sewer spring 100 shown in Figure 2 A has an elongated body 110 having a substantially circular cross-section and a protrusion 120. The protrusion 120 comprises a continuous ridge having a helical shape and is provided around the body 110. Figure 2 B shows a cross-section of the sewer spring 100 over the central axis of the sewer spring 100. In this embodiment, the protrusion 120 follows a helical path such that the distance between the recurring ridge is about three to four times the width of the protrusion 120 where the protrusion 120 protrudes from the body 110. The height of the protrusion is about half of the width of the protrusion 120 where the protrusion 120 protrudes from the body 110.

Figure 3 A shows a side view' of a sewer spring 100 as a third embodiment of the first aspect. The sewer spring 100 shown in Figure 3 A has an elongated body 110 having a substantially circular cross-section and a protrusion 120. The protrusion 120 comprises a continuous ridge having a helical shape and is provided around the body 110. Figure 3 B shows a cross-section of the sewer spring 100 over the central axis of the sewer spring 100. In this embodiment, the protrusion 120 follows a helical path such that the distance between the recurring ridge is about the same as the width of the protrusion 120 where the protrusion 120 protrudes from the body 110. The height of the protrusion is about two to three times the width of the protrusion 120 where the protrusion .1.20 protrudes from the body 110.

In the first, second and third embodiment, the sewer spring 100 comprises a solid body 110. Furthermore, in these embodiments, the protrusion 120 follows a helical path around the solid body 110. In general, the height of the protrusion 120 may be between half to three times the width of the protrusion and the protrusion 120 may be provided on a helical path such that the protrusion is spaced apart one to three times the width of the protrusion. These two parameters may be modified independently from one another.

Alternatively to the solid body, a hollow body may be provided. And as a third characteristic, the protrusion 120 is integrally formed with the body 110. In these embodiments, the body 110 and the protrusion are provided in the same material, an organic thermoplastic polymer material. One reason for this is that this allows for the sewer spring 100 to be manufactured using injection moulding or extrusion. Thermoplastic polymer materials that may be used include, but are not limited to: polyvinyl chloride, polysulfone, polyphenylsulfone, polyoxymethylene, polyvinylidene fluoride, thermoplastic polyurethane and polyether ether ketone. Preferably, the seer spring 100 comprises at least 95% of such thermoplastic polymer material. Further materials may be included for purposes of colouring, filling, reinforcement, other, or a combination thereof.

For sewer springs in general, flexibility, elasticity and strength are important characteristics. For the sewer spring 100 according to the first aspect, characteristics of the material or materials from which the sewer spring 100 is manufactured, are preferably provided such that the Young’s modulus is at least 2 10s MPa. The thickness of the sewer spring 100 is preferably between 6 and 35 millimetres, including the protrusion 120. Widths of 16 millimetres or 22 millimetres are preferred in particular. It should he noted that the sewer spring 100 may also be manufacturing having a diameter of approximately 102 millimetres or even 2 102 millimetres. Whereas a sewer spring 100 having such diameters may be less suitable for cleaning tubing, such spring may be used for drilling in the ground for creating holes for inserting tubing.

Figure 4 A shows a side view of a sewer spring 100 as a fourth embodiment of the first aspect. The sewer spring 100 shown in Figure 4 A has an elongated body 110 having a substantially circular cross-section and a protrusion 120. The protrusion 120 comprises a continuous ridge having a helical shape and is provided around the body 110. In this embodiment, the protrusion 120 follows a helical path such that the distance between the recurring ridge is about the same as the width of the protrusion 120 where the protrusion 120 protrudes from the body 110. The height of the protrusion is about half of the width of the protrusion 120 where the protrusion 120 protrudes from the body 110.

Figure 4 B shows a cross-section of the sewer spring 100 over the central axis of the sewer spring 100. Figure 4 B shows the protrusion 120 to be loosely fit around the body 110. The protrusion 120 may be affixed to the body 110. A fixed connection between to body 110 and the protrusion may be provided at regular spatial intervals. Alternatively or additionally, the protrusion and the 110 may be rigidly connected at opposite end portions of the sewer spring 100.

Figure 5 A shows a side view of a sewer spring 100 as a fifth embodiment of the first aspect. The sewer spring 100 shown in Figure 5 A has an elongated body 110 having a substantially circular cross-section and a protrusion 120. The protrusion 120 comprises a continuous ridge having a helical shape and is provided around the body 110. In this embodiment, the protrusion 120 follows a helical path such that the distance between the recurring ridge is about the same as the width of the protrusion 120 where the protrusion 120 protrudes from the body 110. The height of the protrusion is about half of the width of the protrusion 120 where the protrusion 120 protrudes from the body 110.

Figure 5 B shows a cross-section of the sewer spring 100 over the central axis of the sewer spring 100. Figure 5 B shows the protrusion 120 to be loosely fit around the body 110. The protrusion shown in Figure 5 B has the shape of a conventional helical spring. Figure 5 B shows the "wire" of the helical spring to be round at the outside of the sewer spring 100 and to be flat at a side of the spring facing the body 110. The protrusion 120 thus shaped is more convenient to manufacture using injection moulding.

The protrusion 120 may be affixed to the body 110. A fixed connection between to body 110 and the protrusion may be provided at regular spatial intervals. Alternatively or additionally, the protrusion and the 110 may be rigidly connected at opposite end portions of the sewer spring 100.

Furthermore, Figure 5 B shows a cross-section of the sewer spring 100 over the central axis of the sewer spring 100. Figure 5 B shows the body 110 comprising a core 130 and a cladding 140. In this embodiment, the core 130 comprises a steel wire and preferably a braided steel cable. The cladding 120 preferably comprises a thermoplastic polymer material as discussed above. In such embodiment, the core 130 may be provided in a mould in which the sewer spring 100 is to be formed. Furthermore, in such embodiment, the sewer spring 100 comprises at least 60% of thermoplastic polymer material. And 80% of thermoplastic polymer material is more preferred. In a particular embodiment, the total sewer spring 100, including the protrusion 120, has a diameter of 16 millimetres and the core 130 has a diameter of 6 millimetres. Depending on the height of the protrusion 120 or the protrusions 120, this means that the sewer spring comprises between 14% and 25% of steel. Preferably, the other 75% to 86% is comprised by the thermoplastic polymer material.

Figure 6 A shows a side view of a sewer spring 100 as a sixth embodiment of the first aspect. The sewer spring 100 shown in Figure 6 A has an elongated body 110 having a substantially circular cross-section and protrusions 120.

In this embodiment, the protrusions 120 are provided around the central axis of the body 110, spaced at 120 degrees around the central axis. In alternative embodiments, the protrusions may be spaced at higher or lower angels, between 60 degrees and 180 degrees.

In this embodiment, the protrusions 120 are provided on a helical path such that the distance between the recurring ridge is about on to two times the width of the protrusions 120 where the protrusion 120 protrude from the body 110. Alternatively, the protrusions 120 are provided on virtual circles around and having a plane perpendicular to the central axis. The height of the protrusion is about the same a s the width of the protrusion 120 where the protrusion 120 protrudes from the body 110.

Figure 7 A shows a side view of a sewer spring 100 as a seventh embodiment of the first aspect. The sewer spring 100 shown in Figure 7 A has an elongated body 110 having a substantially circular cross-section. On the body 110, first type protrusions 122 and second type protrusions 124 are provided in an alternating way. The first type protrusions 122 and the second type protrusions 124 have the same shape. The first type protrusions 122 and the second type protrusions 124 are provided as circular discs that are truncated at opposite sides.

The first type protrusions 122 and the second type protrusions 124 skewed relative to one another over an angle of 90 degrees. In alternative embodiments, alternative angles between 45 degrees and 180 degrees may be chosen. As can be seen from Figure 7 B, The discs are truncated such that at a point where distance between an edge of a disc and the outer perimeter is at a minimum, the difference between the height of adjacent protrusion is about a factor of two.

Figure 8 A shows a side view of a sewer spring 100 as an eighth embodiment of the first aspect. The sewer spring 100 shown in Figure 8 A has an elongated body 110 having a substantially circular cross-section and a protrusion 120. The height of the protrusion is about one to two times the width of the protrusion 120 where the protrusion 120 protrudes from the body 110. In this embodiment, the protrusion 120 is provided as a harmonica spring.

Figure 8 B show's a cross-section of the sewer spring 100 over the central axis of the sewer spring 100. Figure 8 B shows the protrusion 120 to be loosely fit around the body 110. The protrusion 120 may be affixed to the body 110. A fixed connection between to body 110 and the protrusion may be provided at regular spatial intervals. Alternatively or additionally, the protrusion and the 110 may be rigidly connected at opposite end portions of the sewer spring 100.

Furtherm ore, Figure 8 B shows a cross-section of the sewer spring 100 over the central axis of the sewer spring 100. Figure 8 B show's the body 110 comprising a core 130 and a cladding 140. In this embodiment, the core 130 comprises a steel ware and preferably a braided steel cable. The cladding 120 preferably comprises a thermoplastic polymer material as discussed above. In such embodiment, the core 130 may be provided a mould in which the sewer spring 100 is to be formed.

Figure 9 A shows a coupling 900 for coupling a first sewer spring to a second sewer spring. Such sewer spring may be a conventional sewer spring, a sewer spring as described above or another sewer spring. The coupling 900 comprises a male coupling member 910 and a female coupling member 950. The male coupling member 910 comprises a male coupling body. From the male coupling body, a protrusion 914 protrudes from a proximal end of the male coupling body. At a distal end of the male coupling body, a first spring connecting member 912 is provided for connecting the male coupling member to a sewers spring. It should be noted that the first spring connecting member 912 may be adjusted to a type of spring to be connected, The first spring connecting member 912 may also be integrally formed with the spring.

Figure 9 A further shows the female coupling member 950. The female coupling member 950 comprises a female coupling body. At a distal end of the female coupling body, a second spring connecting member 952 is provided for connecting the female coupling member to a sewers spring. In the female coupling body, a cavity 954 is provided. The cavity 954 extends from a proximal end of the female coupling body towards, but not up to, the opposite distal end of the female coupling body. The cavity 954 is arranged to accommodate the protrusion 914.

Figure 9 B shows a top view" of the coupling 900. At the top, the male coupling member 910 is shown, with the protrusion 914. At the bottom, the female coupling member 950 is shown, with the cavity 954. The protrusion 914 has a Τ'-shape. The T-shape extends from, a first side of the outer perimeter of the male coupling body to a second side of the outer perimeter of the male coupling body, the second side being opposite to the first side. And the T-shape is provided through a central axis of the male coupling body, provided from the distal end to the proximal end.

The cavity 954 has a T-shape, complementary to the protrusion 914 and arranged to accommodate the protrusion 614. Hence, in this embodiment, the cavity 954 also ranges from a first side of the outer perimeter of the female coupling body to a second side of the outer perimeter of the female coupling body, the second side being opposite to the first side. The cavity 954 has, at a proximal cavity end of the cavity 954 provided at the proximal end of the female coupling body, a proximal cross-section. And the cavity 954 has at a distal cavity end of the cavity 954, closer to the distal end of the female coupling body, a distal cross-section.

For the intended functionality of the coupling 900, the proximal cross-section is at least in one dimension smaller than the distal cross section. In the embodiment shown by Figure 9 A and Figure 9 B, the proximal cross-section is smaller than the distal cross-section in a dimension perpendicular to the length of the cavity, which length runs from the first side to the second side. The protrusion 914 may be accommodated in the cavity 954 by means of a sliding movement of the male coupling member 910 relative to the female coupling member 950. The shapes of the cavity 954 and the protrusion 914 are not limited to the T-shape as discussed above. Other shapes may be envisaged as well. The cavity 954 as well as the protrusion 914 in any case preferably extend from outer perimeters of the coupling bodies to the central axis of the coupling bodies.

Figure 10 A and Figure 10 B show a cross-section of the coupling 900. Figure 10 A shows a male pm 922 provided in the male coupling body and the protrusion 914. And Figure 10 A shows a female pin 962 provided in the female coupling body. The female pin is connected to a shifting member 964 as a control element for moving the female pin 962. In Figure 10 A, the male pin 922 is shown in a first male pin position and the female pin 962 is shown in a first female pin position.

In the first male pin position, the male pin 922 protrudes from the protrusion 914, substantially parallel and optionally in line with the central axis of the male coupling body. And in the first female pin position, the female pin 962 is retracted in the female coupling body, substantially parallel and optionally in line with the central axis of the female coupling body. In the first female pin position, the female pin 962 is retracted in the female coupling body such that in a cavity in which the female pin 962 is provided, leaves room to accommodate the male pin 922. With the male pin 922 in the first male pin position and the female pin 962 in the first female pin position, the male coupling member 910 and the female coupling member 950 are locked, preventing movement.

In Figure 10 B, the male pin 922 is shown in a second male pin position and the female pin 962 is shown in a second female pin position. In the second male pin position, the male pin 922 is retracted in the protrusion 914, substantially parallel and optionally in line with the central axis of the male coupling body. And in the second female pin position, the female pin 962 is provided in the female coupling body, substantially parallel and optionally in line with the central axis of the female coupling body such that the female pin 962 does not leave room for the male pin 922, This is enabled by having the end of the female pin 962 flush with an edge of the cavity 954, The shifting member 964 is arranged for moving the female pin 962 from the first female pin position to the second female pin position. The female pin 962 is preferably biased towards the first female pin position and the male pin 922 is preferably biased towards the first male pin position.

The male pin 922 is provided with a semi-spherical head. This allows the male pin 922 to be pushed to the second male pin position by inserting a further pin in an opening 966 provided in the male coupling body.

It should be noted that in an alternative embodiment, the male pin 922 and the method of operation may be provided in the female coupling member 950 and the female pin and the method of operation may be provided in the male coupling member 910.

The coupling system 900 is preferably provided in a thermoplastic polymer material as discussed above. Certain parts, like the male pin 922, the female pin 952 and/or biasing springs for biasing the male pin 922 and/or the female pin 952 may be provided in steel or another material. The male coupling body and the female coupling body are preferably fully or at least for 80% and more preferably for 95% comprised of any thermoplastic polymer material as discussed above.

Expressions such as "comprise", "include”, "incorporate", "contain”, "is" and "have" are to be construed in a non-exclusive manner when interpreting the description and its associated claims, namely construed to allow for other items or components which are not explicitly defined also to be present. Reference to the singular is also to be construed in be a reference to the plural and vice versa.

In the description above, it will be understood that when an element such as layer, region or substrate is referred to as being “on” or “onto” another element, the element is either directly on the other element, or intervening elements may also be present.

Furthermore, the invention may also be embodied with less components than provided in the embodiments described here, wherein one component carries out multiple functions. Just as well may the invention be embodied using more elements than depicted in the Figures, wherein functions carried out by one component in the embodiment provided are distributed over multiple components. A person skilled in the art will readily appreciate that various parameters disclosed in the description may be modified and that various embodiments disclosed and/or claimed may be combined without departing from the scope of the invention.

Claims

Claims

1. Sewer spring for removing solid material from a tubing, the sewer spring comprising: An elongated body having a substantially circular cross-section and comprising at least an organic thermoplastic polymer material; At least one protrusion provided around the body, spaced at regular distances along the central axis of the body.
2. Sewer spring according to claim 1, wherein the protrusion is helically shaped.
3. Sewer spring according to claim 1 or 2, wherein at least part of the protrusion is at least partially movable relative to the body parallel to the longitudinal axis of the body.
4. Sewer spring according to claim 1, comprising a multitude of protrusions provided around the body, spaced at regular distances along the central axis of the body.
5. Sew-er spring according to claim 4, wherein the protrusions are provided on a helical path along the body.
6. Sewer spring according to claim 4, wherein the multitude of protrusions comprise circular discs that are truncated at opposite sides.
7. Sewer spring according to claim 6, wherein adjacent discs have the straight edges skewed 90 degrees relative to the central axis.
8. Sewer spring according to any of the preceding claims, wherein the protrusion is or the protrusions are integrally formed with the body.
9. Sewer spring according to any of the preceding claims, wherein the body comprises steel reinforcement, provided substantially at the central axis.
10. Sewer spring according to any of the preceding claims, wherein the body comprises at least 95% of the solid organic thermoplastic polymer material.
11. Sewer spring according to any of the preceding claims, wherein the organic thermoplastic polymer material is at least one of the following: Polyvinyl chloride Polysulfone Polyph eny lsu Ifon e Polyoxymethvlene Polyvinylidene fluoride Thermoplastic polyurethane Polyether ether ketone
12. Sewer spring according to any of the preceding claims, having Young's modulus of at least 2 -103 MPa.
13. Female coupling device for a sewer spring having a female coupling body, the female coupling having a distal end for providing a connection to the spring, a proximal end and a central axis from the distal end to the proximal end, the female coupling device comprising: A cavity provided in female coupling body at the proximal end and extending towards the distal end for receiving a protrusion of a male coupling device, the cavity having a proximal cross-section at the proximal end and a distal cross-section towards the distal end, the proximal cross-section being smaller than the distal cross-section in at least one dimension perpendicular to the central axis, and the cavity ranging from the outer perimeter of the female coupling at least towards the central axis; A female pin provided substantially parallel to the central axis, being arranged to slidably move from a first pin position in which the female pin is retracted in a pin holder in the female coupling body such that the pin holder provides room for a male pin to enter to a second pin position in which an end of the female pin is substantially flush with a perimeter of the cavity; Wherein the female coupling comprises an organic thermoplastic polymer.
14. Female coupling according to claim 13, wherein the female pin is biased to the first pin position.
15. Female coupling according to claim 13, further comprising a control element coupled to the female pin for moving the female pin from the first pin position to the second pin position.
16. Male coupling device for a sewer spring having a male coupling body, the male coupling having a distal end for providing a connection to the spring, a proximal end and a central axis from the distal end to the proximal end, the male coupling device comprising: A protrusion provided at the proximal end of the male coupling body, the protrusion having a proximal protrusion end provided at the proximal end of the male coupling body and a distal protrusion end opposite to the proximal protrusion end, the protrusion having a proximal cross-section at the proximal protrusion end and a distal cross-section at the distal protrusion end, the proximal cross-section being smaller than the distal cross-section in at least one dimension perpendicular to the central axis, and arranged to be received by a cavity comprised by a female coupling device; and A male pin provided substantially parallel to the central axis, being arranged to slidably move from a first pm position in which the male pin is retracted in the protrusion to a second pin position in which the male pin protrudes from the protrusion, Wherein the male coupling comprises an organic thermoplastic polymer.
17, Male coupling according to claim 16, wherein the male pin is biased to the second pin position.
18. Coupling system for coupling a first sewer spring to a second sewer spring, the coupling system comprising: A male coupling for a sewer spring having a male coupling body, the male coupling having a distal end for providing a connection to the spring, a proximal end and a central axis from the distal end to the proximal end, the male coupling device comprising a protrusion provided at the proximal end of the male coupling body, the protrusion having a proximal protrusion end provided at the proximal end of the male coupling body and a distal protrusion end opposite to the proximal, protrusion end, the protrusion having a proximal cross-section at the proximal protrusion end and a distal cross-section at the distal protrusion end, the proximal cross-section being smaller than the distal cross-section in at least one dimension perpendicular to the central axis, and arranged to be received by a cavity comprised by a female coupling device; and A female coupling for a sewer spring having a female coupling body, the female coupling having a distal end for providing a connection to the spring, a proximal end and a central axis from, the distal end to the proximal end, the coupling device comprising a cavity provided in female coupling body at the proximal end and extending towards the distal end for receiving a protrusion of a male coupling device, the cavity having a proximal cross-section at the proximal end and a distal cross-section towards the distal end, the proximal cross-section being smaller than the distal cross-section in at least one dimension perpendicular to the central axis, and the cavity ranging from the outer perimeter of the female coupling at least towards the central axis; Wherein: A first of the male coupling and the female coupling comprises a male pin provided substantially parallel to the central axis, being arranged to slidably move from a first pin position in which the male pin is retracted in the protrusion to a second pin position in which the male pin protrudes from the protrusion; A second of the male coupling and female coupling comprises a female pin provided substantially parallel to the central axis, being arranged to slidably move from a first pin position in which the female pin is retracted in a pin holder in the female coupling body such that the pin holder provides room for a male pin to enter to a second pin position in which an end of the female pin is substantially flush with a perimeter of the cavity; and The male coupling and the female coupling comprise an organic thermoplastic polymer,
19, Sewer spring system comprising: A sewer spring according to any of the claims 1 to 12; A female coupling according to any of the claims 13 to 15 at a first end of the sewer spring; and A male coupling according to any of the claims 16 to 1.7 at a second end of the sewer spring, the second end being opposite to the first end.
20, Sewer spring system comprising: A sewer spring according to any of the claims 1 to 12; At a first end of the sewer spring a male coupling for a sewer spring having a male coupling body, the male coupling having a distal end for providing a connection to the spring, a proximal end. and a central axis from the distal end to the proximal end, the male coupling device comprising a protrusion provided at the proximal end of the male coupling body, the protrusion having a proximal protrusion end provided at the proximal end of the male coupling body and a distal protrusion end opposite to the proximal protrusion end, the protrusion having a proximal cross-section at the proximal protrusion end and a distal cross-section at the distal protrusion end, the proximal cross-section being smaller than the distal cross-section in at least one dimension perpendicular to the central axis, and arranged to be received by a cavity comprised by a female coupling device; and At a second end of the sewer spring a female coupling for a sewer spring having a female coupling body, the female coupling having a distal end for providing a connection to the spring, a proximal end and a central axis from the distal end to the proximal end, the coupling device comprising a cavity provided in female coupling body at the proximal end and extending towards the distal end for recei ving a protrusion of a male coupling device, the cavity having a proximal cross-section at the proximal end and a distal cross-section towards the distal end, the proximal cross-section being smaller than the distal cross-section in at least one dimension perpendicular to the central axis, and the cavity ranging from the outer perimeter of the female coupling at least towards the central axis; Wherein: A first of the male coupling and the female coupling comprises a male pin provided substantially parallel to the central axis, being arranged to slidably move from a first pin position in which the male pin is retracted in the protrusion to a second pin position in which the male pin protrudes from the protrusion; A second of the male coupling and female coupling comprises a female pin provided substantially parallel to the central axis, being arranged to slidably move from a first pin position in which the female pin is refracted in a pin holder in the female coupling body such that the pin holder provides room for a male pin to enter to a second pin position in which an end of the female pin is substantially flush with a perimeter of the cavity; and The male coupling and the female coupling comprise an organic thermoplastic polymer.