EP3048202B1

EP3048202B1 - Cylindrical pile and cylindrical pile extension element

Info

Publication number: EP3048202B1
Application number: EP16150613.4A
Authority: EP
Inventors: Thorulf HAMFORS
Original assignee: Scandia Steel Forvaltning AB
Current assignee: Scandia Steel Forvaltning AB
Priority date: 2015-01-23
Filing date: 2016-01-08
Publication date: 2017-08-16
Anticipated expiration: 2036-01-08
Also published as: EP3048202A1; SE538465C2; SE1550072A1

Description

The present invention relates to cylindrical construction piles. Specifically, the present invention relates to such piles to be used as reinforcing or supporting construction elements in large and/or heavy structures, such as buildings, bridges and the like. In particular, the present invention relates to threaded such piles, which threads have certain characteristics.
Such piles are for instance used to transfer gravitational forces from the weight of heavy structures down into the ground, to stable bedrock. Normally, piles are arranged in bore holes in the ground, which holes may be quite long, such as at least tens of meters. As a result, corresponding piles also need to be long, which is typically achieved by providing a number of pile elements that may be attached one to the other to provide a single, long pile. One conventional way of achieving this is by using weld joints. Another is to use threaded screw joints. Both these methods achieve a connected, long pile, formed by several pile elements arranged one after the other in a permanently stable way. Screw joints allow for a quicker installation than weld joints.
However, high demands are placed on such joints. They must be able to support the intended load for long periods of time, such as at least 100 years, despite corrosion and ground movements. This applies both to axial compression and bending forces, but also to axial pulling forces. Typically, the joints need to be at least as strong as a pile section of corresponding length. In typical installation projects, it is very important to keep pile installation time to a minimum, at the same time as high reliability requirements must be met. The installation environment is often very dirty and exposed to the elements.
Many screw joint pile designs have been proposed to solve these problems. Examples comprise EP1010815 B1 , and also EP2256251 A2 , US 4444421 B and SE523782 B .
In a tubular screw joint, a "pin end" is an externally threaded male member, arranged to engage and cooperate with a "box end", which is an internally threaded, female member. Typically, each pile element comprises two opposite pin ends, and individual pile elements are attached one to the other, in their longitudinal direction, using a "sleeve", to form a connected, long pile. A "sleeve" is a cylindrical part comprising two opposite box ends, each arranged to engage with a corresponding pin end of a respective pile element.
It would be desirable to achieve a screw joint pile element which is better than prior art such pile elements in terms of installation quickness and reliability. Specifically, a pile element is desired that can offer such qualities in dirty environments and using manual installation methods.
The present invention solves this and other problems. In particular, it solves the problem by proposing a thread of particular configuration in a cone-shaped thread joint for such pile- and sleeve elements.
Hence, the invention relates to a cylindrical pile element with a longitudinal axis, which pile element is arranged for use as a reinforcing or supporting construction element, which pile element has a cross-sectional cylinder diameter of at least 70 mm, which pile element is arranged to be lengthwise extendable using a cylindrical sleeve element, using a male pile element thread comprised in a pin end of the said pile element and arranged to engage with a corresponding female sleeve element thread comprised in the said sleeve element at a respective box end of the sleeve element, which pile element thread is generally tapered from a relatively wider part towards a relatively narrower part closer to the said pin end, which pile element is characterised in that the side flank of the pile element thread facing towards the pin end is inclined between 15° and 25° in relation to a plane which is perpendicular to the longitudinal axis of the pile element, and in that the side flank of the pile element thread facing away from the pin end is inclined between 6° and 8° in relation to a plane which is perpendicular to the longitudinal axis of the pile element.
Furthermore, the invention relates to a cylindrical pile sleeve element with a longitudinal axis, which sleeve element is arranged for use as a reinforcing or supporting construction element, which sleeve element has a cross-sectional cylinder diameter of at least 80 mm, which sleeve element is arranged for extending lengthwise a cylindrical pile element according to any one of the preceding claims, using a female sleeve element thread comprised in the sleeve element at a respective box end of the sleeve element, and arranged to engage with the male pile element thread of said pile element, which sleeve element thread is generally tapered from a relatively narrower part towards a relatively wider part closer to the said box end, which sleeve element is characterised in that the side flank of the sleeve element thread facing away from the box end is inclined between 15° and 25° in relation to a plane which is perpendicular to the longitudinal axis of the sleeve element, and in that the side flank of the sleeve element thread facing towards the box end is inclined between 6° and 8° in relation to a plane which is perpendicular to the longitudinal axis of the sleeve element.
In the following, the invention will be described in detail, with reference to three embodiments of the invention as shown in the enclosed drawings, wherein

Figure 1a is a cross-section of a pin end of a pile element according to a first exemplifying embodiment of the present invention;
Figure 1b is a magnification of the detail "A" of figure 1a;
Figure 2a is a cross-section of a sleeve according to said first embodiment;
Figures 2b and 2c are respective magnifications of details "A" and "B", respectively, of figure 2a;
Figure 3a is a cross-section of a made-up aggregate comprising a first and a second pile element and a sleeve according to said first embodiment;
Figure 3b is a magnification of the detail "A" of figure 3a;
Figure 4a is a cross-section of a pin end of a pile element according to a second exemplifying embodiment of the present invention;
Figure 4b is a magnification of the detail "A" of figure 4a;
Figure 5a is a cross-section of a sleeve according to said second embodiment;
Figures 5b and 5c are respective magnifications of details "A" and "B", respectively, of figure 5a;
Figure 6a is a cross-section of a made-up aggregate comprising a first and a second pile element and a sleeve according to said second embodiment;
Figures 6b and 6c are respective magnifications of the details "A" and "B", respectively, of figure 6a;
Figure 7a is a cross-section of a pin end of a pile element according to a third exemplifying embodiment of the present invention;
Figure 7b is a magnification of the detail "A" of figure 7a;
Figure 8a is a cross-section of a sleeve according to said third embodiment;
Figure 8b is a magnification of detail "A" of figure 8a;
Figure 9 is a simplified view of a part of a pile element and a part of a sleeve, illustrating the terminology used herein; and
Figure 10 is a simplified view of a pile aggregate comprising three pile elements and three sleeve elements according to the invention.

The figures also show measures, given in mm and degrees, as applicable. An "R" followed by a number indicates the curvature radius of a corner. For instance, "R0,25" means a curvature radius of an indicated corner of 0.25 mm.
Some figures comprise a "1" or "2" inside a circle. This denotes a pile element "1" or a sleeve element "2", respectively.
Figure 9 illustrates the terminology used herein. A simplified and not-to-scale detail section view of the respective wall of a cylindrical pile element 10 and a cylindrical sleeve element 20 are shown. It is understood that the sleeve element 20 is arranged to fit snugly and concentrically around the pile element 10 when engaged in a made-up threaded relationship.
The pile element 10 comprises a pin end 11. As used herein, the term "pin end" may refer to either the end itself or to the part of the pile 10 near the end itself, depending on the circumstances. The corresponding is true regarding the term "box end". The pile element 10 also comprises external threads 12. "V" denotes a longitudinal direction of the pile element 10 and the sleeve element 20 (the same in figure 10).
The sleeve element 20 comprises a box end 21, and a second box end 27 (not shown), as well as internal threads 22. In general, threads 12, 22 comprise side flanks 24, 25 separated by crests 23 and roots 26.
In the following, the present invention will be explained in relation to the three embodiments shown in figures 1a-3b; 4a-6b; and 7a-8b, respectively.
Hence, the present invention relates to a cylindrical pile element with a longitudinal axis, which pile element is arranged for use as a reinforcing or supporting construction element, for instance in the construction of buildings and/or traffic infrastructure. The pile has a cross-sectional cylinder diameter of at least 70 mm. As shown in the figures, the thread of the pile element is conical in the sense that the pile element thread is generally tapered from a relatively wider part, extending along a longer section, such as covering the majority of the pile element length, towards a relatively narrower part closer to the pin end of the pile element. This implies that the thickness of the cylinder wall of the pile element is also tapered towards a thinner part near the pin end.
In the opposite end of the pile element, a corresponding narrowing exists. The cylinder diameter referred to above pertains to the maximum diameter away from the conical section of the pile.
Moreover, the pile element is arranged to be lengthwise extendable using a cylindrical sleeve element, using a male pile element thread comprised in a pin end of the said pile element, which male thread is arranged to engage with a corresponding female sleeve element thread comprised in the said sleeve element at a respective box end of the sleeve element. Hence, using sleeves 20a, 20b of the type illustrated, in a simplified fashion, in figure 9, several pile elements 10a, 10b, 10c may be joined together to form a single, connected and longer pile 30. This is illustrated in figure 10, in a simplified and not-to-scale manner.
According to the invention, the side flank of the pile element thread facing towards the pin end of the pile element is inclined between 15° and 25°, preferably about 20°, most preferably 20°, in relation to a plane which is perpendicular to the longitudinal axis V of the pile element. When the pile element 10, and the pile 30, is installed vertically, this axis V is thus also vertical. Furthermore, the opposite side flank, that is the side flank of the pile element thread facing away from the pin end of the pile element, is inclined between 6° and 8°, preferably about 6°, most preferably 6°, in relation to a plane which is perpendicular to the longitudinal axis V of the pile element. This is illustrated in figures 1b (110° and 96° angle to longitudinal direction); 4b (110° and 84° angle to longitudinal direction); and 7b, respectively.
As stated above, the threads are in general conical, preferably at a general angle of 3-4° to the longitudinal direction V - see figures 1b (3°); 4b (3°) and 7a (4°). The combination of generally conical threads and the type of angled side flanks discussed above has been found, by the present inventors, to be superior for the specific application of construction piles. Namely, they offer a very strong joint between pile and sleeve once fastened with appropriate torque, at the same time as their installation can be made fast and in a highly reliable way. A next pile element can simply be put, tipped or tilted down into the hole of the sleeve, which is mounted on the previous pile element (which is then arranged in a bore hole in the ground), and rotated into threaded engagement with the sleeve, with a low risk of the threads becoming intertangled due to rotational or angular mismatch between pile element and sleeve element. This is the case even when used in uncontrolled, heavily dirty environments, such as at a construction site with presence of moist, dirt, sand, gravel and so forth.
In particular, the above specified flank angles have proven to be advantageous in the case shown in the figures, in which the crest of the pile element thread comprises a flat surface which is substantially parallel to the longitudinal axis V of the pile element along substantially the whole length of the male thread. Hence, as seen in the cross-section shown in the figures, the respective flat surfaces of consecutive crests are parallel displaced one the next, so that all such surfaces are essentially parallel to the longitudinal direction V of the pile element. This provides a very high chance that a coarsely inserted pile element can engage directly, in a problem-free way, with its sleeve element, in particular in combination with the above-discussed flank angles.
It is preferred that the pile element thread has a constant pitch, preferably throughout the whole or substantially the whole length of the pile element thread. The corresponding is preferably also true regarding the present sleeve element.
As seen in the figures, inner and outer corners of the threaded parts are in general rounded. In particular, it is preferred that all external and internal corners of the pile element thread are rounded using a respective curvature radius of between 0.1 and 0.5 mm. The corresponding is preferably also true regarding the present sleeve element.
Preferably, the pile element, and also correspondingly the sleeve element, is made of steel material as one integrated material body. Preferably, the steel material is a high strength structural steel such as S460 or comparable qualities.
Each pile element is preferably at least about 1 meter long, in a more preferred embodiment and primarily intended for heavy installations at least about 3 meters long, from pin end to pin end. Preferably, the pile element comprises two opposed pin ends, each comprising a respectively substantially identical male pile element thread according to the above.
The present invention further relates to a cylindrical pile sleeve element according to the above and as shown in the figures. Such a sleeve element is, like the pile element, arranged for use as a reinforcing or supporting construction element, and has a cross-sectional cylinder diameter of at least 80 mm. Furthermore, the sleeve element is arranged for extending lengthwise a cylindrical pile element of the above described type, using a female sleeve element thread comprised in the sleeve element at a respective box end of the sleeve element, and is arranged to engage with the male pile element thread of the said pile element. The sleeve element thread is generally tapered from a relatively narrower part towards a relatively wider part closer to the said box end.
As is the case with the pile element, the side flank of the sleeve element thread facing away from the box end is inclined between 15° and 25° in relation to a plane which is perpendicular to the longitudinal axis V of the sleeve element, and in that the side flank of the sleeve element thread facing towards the box end is inclined between 6° and 8° in relation to a plane which is perpendicular to the longitudinal axis V of the sleeve element.
It is preferred that the sleeve element thread corresponds or at least substantially corresponds to the pile element thread in terms of side flank-, crest- and root angles and dimensions. However, it is preferred, as illustrated in figures 3b and 6b, that a certain play of preferably less than 1 mm, more preferably less than 0,5 mm, most preferably 0,39 mm, is present along the V direction at the less angled side flanks during fully made-up engagement between pile element and sleeve element.
According to one preferred embodiment, the sleeve element comprises an additional female thread arranged at an additional box end of the sleeve element, which additional female thread is substantially identical to the said sleeve element thread. Hence, each sleeve element is arranged to interconnect two pile elements, one at each side of the sleeve element, forming a pile aggregate according to the present invention.
In such a pile aggregate, each respective pile element thread is preferably screwed fully into the corresponding sleeve element thread so that a fully made-up thread engagement is achieved between the pile element and the sleeve element.
In a pile aggregate according to the present invention in which two pile elements are interconnected by fully made-up thread engagements at opposite respective ends of the sleeve element, the respective sleeve element threads are preferably arranged on the sleeve element so that the distance between the first and second pile elements is between 3 and 15 mm. This is illustrated in figures 3b (9.5 mm) and 6b (5 mm).
Furthermore, the shape of the sleeve element is preferably such that, in fully made-up engagement with the pile element, there is a play of at least 0.3 mm (see figure 6c) between the inner surface of the sleeve element and the outer surface of the pile element along a distance of at least 3 mm from the box end of the sleeve element.
Above, preferred embodiments have been described. However, it is apparent to the skilled person that many modifications may be made to the disclosed embodiments without departing from the basic idea of the invention.
There are many measures given in the drawings, which are all part of the disclosed exemplifying embodiments. At the same time, it is realized that these detailed examples merely show three different possible pile- and sleeve element designs falling under the protective scope of the enclosed claims.
Hence, the invention is not to be limited to the described embodiments, but may be varied within the scope of the enclosed claims.

Claims

Cylindrical pile element (10) with a longitudinal axis (V), which pile element (10) is arranged for use as a reinforcing or supporting construction element, which pile element (10) has a cross-sectional cylinder diameter of at least 70 mm, which pile element (10) is arranged to be lengthwise extendable using a cylindrical sleeve element (20), using a male pile element thread comprised in a pin end (11) of the said pile element (10) and arranged to engage with a corresponding female sleeve element thread comprised in the said sleeve element (20) at a respective box end (21) of the sleeve element (20), which pile element thread is generally tapered from a relatively wider part towards a relatively narrower part closer to the said pin end (11), characterised in that the side flank of the pile element thread facing towards the pin end (11) is inclined between 15° and 25° in relation to a plane which is perpendicular to the longitudinal axis (V) of the pile element (10), and in that the side flank of the pile element thread facing away from the pin end (11) is inclined between 6° and 8° in relation to a plane which is perpendicular to the longitudinal axis (V) of the pile element (10).
Cylindrical pile element (10) according to claim 1, characterised in that the side flank of the pile element thread facing towards the pin end (11) is inclined 20° in relation to a plane which is perpendicular to the longitudinal axis (V) of the pile element (10) along substantially the whole length of the male thread.
Cylindrical pile element (10) according to claim 1 or 2, characterised in that the side flank of the pile element thread facing away from the pin end (11) is inclined 6° in relation to a plane which is perpendicular to the longitudinal axis (V) of the pile element (10) along substantially the whole length of the male thread.
Cylindrical pile element (10) according to any one of the preceding claims, characterised in that the crest of the pile element thread comprises a flat surface which is substantially parallel to the longitudinal axis (V) of the pile element (10) along substantially the whole length of the male thread.
Cylindrical pile element (10) according to any one of the preceding claims, characterised in that the pile element thread has constant pitch.
Cylindrical pile element (10) according to any one of the preceding claims, characterised in that all external and internal corners of the pile element thread are rounded using a respective curvature radius of between 0.1 and 0.5 mm.
Cylindrical pile element (10) according to any one of the preceding claims, characterised in that the pile element (10) is made of steel material as one integrated material body.
Cylindrical pile element (10) according to any one of the preceding claims, characterised in that the pile element (10) is at least 1 meter long.
Cylindrical pile element (10) according to any one of the preceding claims, characterised in that the pile element (10) comprises an additional male thread arranged at a second, opposed, pin end of the pile element (10), which additional male thread is substantially identical to the said pile element thread.
Cylindrical pile sleeve element (20) with a longitudinal axis (V), which sleeve element (20) is arranged for use as a reinforcing or supporting construction element, which sleeve element (20) has a cross-sectional cylinder diameter of at least 80 mm, which sleeve element (20) is arranged for extending lengthwise a cylindrical pile element (10) according to any one of the preceding claims, using a female sleeve element thread comprised in the sleeve element (20) at a respective box end (21) of the sleeve element (20), and arranged to engage with the male pile element thread of said pile element (10), which sleeve element thread is generally tapered from a relatively narrower part towards a relatively wider part closer to the said box end (21), characterised in that the side flank (25) of the sleeve element thread facing away from the box end (21) is inclined between 15° and 25° in relation to a plane which is perpendicular to the longitudinal axis (V) of the sleeve element (20), and in that the side flank (24) of the sleeve element thread facing towards the box end (21) is inclined between 6° and 8° in relation to a plane which is perpendicular to the longitudinal axis (V) of the sleeve element (20).
Cylindrical pile sleeve element (20) according to claim 10, characterised in that the sleeve element (20) comprises an additional female thread arranged at an additional box end of the sleeve element (20), which additional female thread is substantially identical to the said sleeve element thread.
Pile aggregate (30) comprising a cylindrical pile element (10) according to any one of claims 1-9 and a cylindrical pile sleeve element (20) according to claim 10 or 11, wherein the pile element thread is screwed fully into the sleeve element thread so that a made-up thread engagement is achieved between the pile element (10) and the sleeve element (20).
Pile aggregate (30) comprising first and second cylindrical pile elements (10a,10b, 10c) according to claim 9 and a cylindrical pile sleeve element (20a,20b) according to claim 11, wherein the pile element thread of the first pile element (10a) is screwed fully into the sleeve element thread so that a made-up thread engagement is achieved between the first pile element (10a) and the sleeve element (20a), wherein the additional pile element thread of the second pile element (10b) is screwed fully into the additional sleeve element thread so that a made-up thread engagement is achieved between the second pile element (10b) and the sleeve element (20a), characterised in that the respective sleeve element threads are arranged on the sleeve element (20a) so that the distance between the first and second pile elements (10a,10b) is between 3 and 15 mm.