EP0418226B1

EP0418226B1 - Anchoring device

Info

Publication number: EP0418226B1
Application number: EP88903458A
Authority: EP
Inventors: Sven-Göran LARSSON
Original assignee: LARSSON SVEN GOERAN; Larsson Sven-Goran
Current assignee: LARSSON, SVEN-GOERAN
Priority date: 1987-04-13
Filing date: 1988-04-12
Publication date: 2002-01-23
Anticipated expiration: 2008-04-12
Also published as: DK164184C; DK684188D0; ATE212406T1; WO1988008066A1; EP0418226A1; FI885750A0; DK164184B; NO885417L; NO165648B; NO165648C; DK684188A; CA1328975C; NO885417D0; FI885750A; SE456833B; SE8701535D0; DE3856513D1

Abstract

A device for anchoring in the ground comprises two parts (1, 2) relatively movable in axial direction and a transversally expansible arrangement (4) adapted to be actuated for expansion upon relative movement between the parts for the purpose of anchoring the device in the ground.

Description

This invention relates to a device for anchoring in the ground and showing two parts relatively movable in the axial direction and a transversally expansible arrangement adapted to be actuated for expansion upon relative movement between the parts for the purpose of anchoring the device in the ground, and that one of the parts is formed by a rod whereas the other part is formed by a tube surrounding the rod, whereby the expansible arrangement comprises flareable members, which form parts of a sleeve provided with cuts extending along a portion of the sleeve from the upper end of the sleeve towards the lower end thereof, whereby one end of the tube is a dapted to actuate the flareable members radially beginning at their upper ends, said flareable members obtaining support from the rod at their lower ends.
A common method for providing stakes or posts on the ground is to dig a pit and then cast a concrete foundation in the pit. The stake proper may be directly located in this concrete foundation so as to make the stake to be secured by casting in the foundation or alternatively members may be secured by casting in the foundation so as to serve for fixation of the stake after curing of the concrete. This procedure requires considerable effort and time. Therefore, one has tried to use various stake constructions which are located in the ground by simply being pressed down therein, either directly into an unprepared ground layer or into holes prebored therein. This has, however, resulted in considerable problems. More specifically, freezing of the soil exerts a lifting action on the stake pressed into the ground and this causes the stake to be pressed upwardly with the time. This is extremely annoying in connection with e.g. fences since it causes deteriorated anchorage of the stakes and moreover, the fence tends to assume wave form due to the fact that varying nature of the soil along the extent of the fence causes different amount of pressing of the different stakes upwardly. A further problem with this latter type of stakes is that its stability to transverse forces, i.e. horisontal actuation of stake parts above ground or elements connected thereto, is relatively poor.
A ground anchor is prior known from US-A-3.855.745 and includes a rod having a pointed tip with a tapered shoulder connected to the bottom of the rod. Overfitting the rod to bear against the tapered shoulder is an anchor sleeve having cuts longitudinally from a lower end thereof for flaring the end portion of the anchor sleeve against the tip resulting in outstanding members of the anchor sleeve which members can engage the surrounding ground. A driving tube is used for the flaring operation. In forming the anchor for anchoring the rod and the tip are driven into the ground by using the driving tube which is first fitted over the length of the rod so the end of the driving tube engages the tip. The driving tube is then driven directly by impact upon its free end. After the rod has been driven to the desired location within the ground, the driving tube is removed therefrom and the flareable anchor sleeve is inserted over the rod. Since the rod and the tip have been driven into the ground one hopes that a channel along the length of the rod will remain, enabling the anchor sleeve to be slideably located adjacent the tip. Once the flareable anchor sleeve has been placed over the rod, the driving tube is then again located over the rod and brought to engagement with the end portion of the anchor sleeve. The driving force is again reapplied to the driving tube. As the driving force is received by the anchor sleeve, the lower portion of the sleeve is driven into the shoulder of the tip. Because of the taper of the tip toward the shoulder, the sleeve splits and flares outwardly. After the anchor sleeve has been flared, the driving tube is removed. Thus, the anchor sleeve is forced by the driving tube in the direction of the bottom of the rod or said channel to be flared. The rod cannot be moved in the opposite direction, i.e. towards the surface of the ground, during the anchoring operation. Once the anchor is completed any connection or load to the rod above the surface of the ground can force the flared outstanding members to remove to their initial position and undermine the anchoring.
The object of the present invention is to reduce the disadvantages discussed hereinabove and accordingly to achieve a device giving a very good anchorage against lifting of the stake due to freezing of the soil or other influence. The rod and the sleeve including the expansible arrangement are located in the ground simultaneously avoiding the risk of ground-slip into a channel which in turn prevent an expansible arrangement to be located within the ground. Once the device is completed anny connection or load to the rod above the surface of the ground improve the engagement of the expansible arrangement or its flareable members into the ground and the anchoring as well, as the rod and the expansible arrangement are arranged to move towards the surface of the ground during the anchoring operation.
The device is characterized in that the rod is in connection with said flareable members, that the sleeve together with the rod is arranged to be moved in a direction towards the tube for said expansion of the expansion arrangement, whereby said flareable members are arranged to flare outwardly for penetration into the ground and in that the portions flared of the flareable members are arranged to be actuated to be additionally flared outwardly by the engagement into the ground when the rod is moved in said direction.
With reference to appended drawings, a more specific description of embodiment examples of the invention follows hereinafter.
In the drawings:
fig. 1 is a perspective view of the device according to the invention prior to expansion of its expansible arrangement,
fig. 2 is a perspective view of the device after expansion of the expansible arrangement,
fig 3 is a view similar to fig 1 but illustrates only a rod contained in the device with accompanying expansible arrangement;
fig 4 is a perspective view of the device according to fig 3 but in a somewhat different perspective angle and with the expansible arrangement illustrated in expanded state;
fig 5 is a view illustrating the device located in the ground prior to expansion of the expansible arrangement;
fig 6 is a view of the device located in the ground after expansion of the expansible arrangement;
fig 7 is a cut view illustrating an alternative embodiment during driving into the ground; and
fig 8 is a view similar to fig 7 but illustrating the device in anchored state.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The device according to the invention comprises two parts 1, 2 relatively movable in their axial direction and an arrangement 3 expansible in transverse direction and adapted to be actuated for expansion upon relative movement between the parts for the purpose of anchoring the device in the ground.
One of the parts is formed by a rod 1 whereas the other part is formed by a tube 2 surrounding the rod.
The expansible arrangement 3 comprises anchoring members 21 associated to rod 1. More specifically, a sleeve 4 is in the example arranged about the rod and this sleeve is provided with cuts 5 extending along a part of sleeve 4. In the embodiment the cuts 5 extend entirely axially along the sleeve and four cuts are uniformly distributed about the sleeve. The cuts extend from one end of the sleeve towards the other. More specifically, the cuts 5 extend from the end 6 of the sleeve adjacent to tube 2, as viewed in the state of the device prior to expansion of sleeve 4. The anchoring members 21 are formed by the tongue-like portions of the sleeve located between cuts 5.
As appears most closely from figs 3 and 4, sleeve 4 is held relative to rod 1 so that the sleeve obtains support from rod 1 in at least one direction along rod 1 and the axis of the device. This direction is in fig 3 indicated with arrow P1. This support function may be realized in various ways. In figs 3 and 4 it is indicated that there is to the lower end of rod 1 attached a stop member 7, which may be formed by a circular washer or ring and is intended to limit the movement of sleeve 4 along arrow P1. Sleeve 4 is slid on to the rod 1 and is secured to stop member 7 by means of e.g. welding.
Tube 2 is adapted to actuate sleeve 4 with one end 8 thereof so that the sleeve expands in the way illustrated in fig 2. More specifically, tube 2 is adapted to enter into the sleeve with its end 8 so that the anchoring members 21 of the sleeve defined by adjacent cuts 5 are flared outwardly. Members 21 project mostly at sleeve end 6 and then in decreasing degree downwardly as appears from figs 2, 4 and 6. This flaring beginning at the upper end of sleeve 4 causes an excellent protection against undesired lifting of the device since the portions flared outwardly obtain good support from the ground and moreover are actuated, upon tendency to lifting of the device, to be additionally flared outwardly with even more improved capacity to withstand lifting as a result. The members 21 flared outwardly also give the device increased capacity to withstand sidewardly directed loads on the device or components attached thereto.
It appears from figs 1 and 5 that the end 8 of tube 2 is shaped conical to facilitate introduction of the tube in between members 21 or sleeve 4 and rod 1. As a complement thereto, sleeve end 6 may be designed conical on the inner side so that the internal diameter of sleeve 4 at the end 6 increases in the direction towards tube 2.
It is preferred that the internal surface of sleeve 4 surrounds rod 1 with some clearance to simplify introduction of tube 2 between the inner surface of sleeve 4 and rod 1. Sleeve 4 may for example have an internal diameter exceeding the external diameter of rod 1 with between 5 and 15 %. In a commercial embodiment of the device for fence purposes, rod 1 may have an external diameter of 20 mm whereas the internal diameter of sleeve 4 is 22 mm.
It is suitable that the external diameter of tube 2 is generally the same as the external diameter of sleeve 4 prior to expansion/flaring of the sleeve to facilitate movement of the device into the ground. The internal diameter of tube 2 exceeds preferably the external diameter of rod 1 with between 5 and 15 %. In a commercial embodiment tube 2 is intended to have an internal diameter of 22 mm whereas the external diameter of rod 1, as mentioned above, is 20 mm. Tube 2 should have such clearance relative to rod 1 that it is relatively readily displaceable along the rod but the clearance should not be so considerable that rod 1 may move too much transversally within tube 2 since, as will be described hereinafter, it is intended in this embodiment to secure further elements to rod 1.
If it is the intention to move or drive the device into a prebored hole in the ground it may be suitable that the end formed by rod 1 and/or stop member 7 and/or sleeve 4 is relatively blunt so that the device stops against the bottom of the hole. If the intention is instead to press or ram the device into the ground without preboring, the end should instead of that which is the case in the embodiment illustrated in the drawings be provided with a sharp lower end.
It is preferred that sleeve 4 prior to expansion has a hollow cylindrical form.
Tube 2 is provided with members 9 projecting from the mantle of the tube to stabilize the same and accordingly the rod 1 received within the tube by ground engagement. Said member has in the embodiment the character of two vertically orientated wings 10, 11, which preferably form an angle about 90° between themselves. The wings 10 and 11 may form portions of a single sheet piece which is bent about 90° along a bending zone 12 having a radius of curvature generally corresponding to the radius of the external surface of tube 2. The sheet piece is attached to tube 2 e.g. by welding so that the bending zone 12 adjoins to the mantle of tube 2 and is parallel to the axis of tube 2. Furthermore, wings 10, 11 have with preference lower edges 15, 16, which in a vertical position of tube 2 extend obliquely upwardly from tube 2. Wings 10, 11 have further upper edges 13, 14 preferably parallel to planes perpendicular to the longitudinal axis of tube 2. Wings 10, 11 may each in practice have a generally triangular form. Wings or members 10, 11 may, however, also be given other suitable forms; essential for the stabilizing action aimed at is that the wings or members protrude outwardly from the tube and engage with the surrounding ground so that loads occurring on rod 1 or tube 2 and directed at an angle to their longitudinal directions are transferred to larger ground surfaces than if such wings or members were not provided. Since in this embodiment wings 10, 11 extend at an angle to each other they will function stabilizing in all transverse directions.
Wings or members 10, 11 are arranged at the upper end of tube 2. As will be discussed hereinafter the upper end of tube 2 is intended to be located adjacent to the ground surface when the device is located in the ground.
Rod 1 comprises in the embodiment a thread 17 adapted to cooperate with a nut 22 adapted to directly or via an intermediate washer or the like obtain support against the tube at its upper end, whereby rod 1 and tube 2 are forcibly relatively movable by turning nut 22.
When locating the device according to the invention in the ground, one acts as follows: If the ground is very hard a hole can be prebored and the device thereafter be rammed or pressed down to the position according to fig 5. No preboring is required in relatively soft ground. The ramming or pressing should be carried out so that members 21 are not flared outwardly during this operation. Accordingly, the ram or press forces should be applied on rod 1 or simultaneously thereon and on tube 2. In the position according to fig 5 the wings 10, 11 are driven down into the ground whereas the upper end of the tube is located above ground surface. Thereafter such forces are exerted on rod 1 and tube 2 by means of nut 22 that rod 1 and sleeve 4 move upwardly and end 8 of the tube penetrates into sleeve 4 and successively flares its portions 21 delimited by the cuts 5 outwardly in the manner indicated in fig 6. This function is obtained by simply turning nut 22. The device is such that tube 2 with accompanying wings 10, 11 remain generally stationary during movement upwardly of rod 1 and anchoring members 21. It has turned out that this function is extremely advantageous for safe and efficient flaring of members 21 in that their flaring will be promoted by contact with the ground since members 21 simultaneously as they are flared outwardly also move upwardly by their connection to rod 1. The simultaneous flaring and movement upwardly of members 21 cause that they generally will penetrate into the ground substantially parallel to their longitudinal directions, i.e. with their upper ends cutting themselves into the ground. In absence of the described movement upwardly of anchoring members 21, these would have to be pressed into the ground with their large external surfaces foremost. This would cause requirement for very great forces and would furthermore cause risk for undesired distortion of anchoring members 21.
It has surprisingly turned out that tube 2 remains generally stationary in its longitudinal direction also without applying any external holding forces on tube 2. It has even turned out in connection with prebored holes that rod 1 and anchoring members 21 primarily move upwardly whereas tube 2 remains stationary. The explanation appears to be that anchoring members 21 by being flared outwardly beginning from their upper ends act as abutments relative to the ground. To achieve the desired movement upwardly of rod 1 and flaring members 21 during the anchoring operation the device should of course be such that the unit formed by rod 1 and flaring members 21 is in absence of components operating as an obstacle to the desired movement upwardly. Furthermore, it is promoting to the desired movement upwardly of rod 1 and flaring members 21 if the initial location of the device to the position according to fig 5 occurs by such pressing or ramming downwardly that tube 2 by friction will be held in position by surrounding soil. For the rest it may be pointed out that wings 10 and 11 to some extent will act as hindrance to movement downwardly of tube 2 but it has been found in tests that tube 2 remains in the intended position also without wings 10 and 11. For the rest it is suitable that possible preboring in the ground occurs to such a small depth or with such a small diameter that ramming or pressing downwardly of the device into the ground must occur since this causes the device to obtain good initial transverse stability by intimate contact between tube 2 and surrounding soil.
After having carried out the anchorage operation nut 22 is intended to remain in place so as to prevent movement upwardly of tube 2 relative to rod 1. Arbitrary brackets or the like for further components may for the rest be clamped by means of the nut 22 between itself and the upper end of tube 2. Alternatively, rod 1 may from the start have such large length that it without further accessories may carry out the desired function, such as to serve for carrying or supporting signs, illumination, fittings, fences or other arbitrary devices. In the embodiment particular auxiliary elements are, however, intended to be attached to rod 1. The thread 17 of rod 1 may be used for this purpose. On this thread a sleeve 18 is in the embodiment (fig 6) mountable by being provided with corresponding attachment means in the form of an internal thread. A stake element 19 is subsequently mountable to sleeve 18 e.g. by being pushed on to the same and mutual securing of sleeve 18 and stake element 19 may occur by means of diagrammatically indicated securing members 20 in the form of e.g. screws or pins. A fence or other arbitrary devices may then be attached to stake element 19.
Since the flaring operation, i.e. the flaring of members 21, is carried out by turning nut 22 it will not subject the device to any downwardly directed forces; all forces will accordingly be exerted between tube 2 and rod 1 and, in accordance with that described, will tend to cause movement upwardly of rod 1 and members 21.
The variant illustrated in figs 7 and 8 is basically similar to the embodiment described and like reference characters will hereinafter be used for corresponding parts. The device comprises also here a rod 1 and a tube 2 surrounding the same. As before, a sleeve 4 is attached to the lower end of rod 1 and comprises cuts 5 starting from the upper end of the sleeve. The portions between these cuts 5 form flareable anchoring members 21. Tube 2 is formed by two sections, namely a lower 23 and an upper 24, the upper being attached to the lower and having such a large diameter that it engages about the upper end of the lower section 23. The upper tube section 24 comprises means 25, here in the form of a flange, serving for connection to arbitrary components. To the external side of tube 2 wing-like stabilizing members 10, 11 are attached and these are orientated in parallel and are in practice located in one and the same plane. If transverse stabilization also is required perpendicularly to this plane further stabilizing wings could be arranged at an angle to this plane. The lower edges 15, 16 of the wings extend obliquely upwardly in a direction away from the external mantle of tube 2.
In this embodiment rod 1 has a considerably smaller diameter than the internal diameter of tube 2. In the area of the lower end of tube 2 there is provided a guide member 26 comprising a hole receiving rod 1 and having a slightly larger diameter than the latter. Members 26 may be formed by a washer or the like welded to tube 2. Rod 1 comprises also here a thread 17 intended for engagement with a nut 22 to carry out flaring of members 21. Nut 22 is intended to obtain support against tube 2 via an abutment member 27 suitably having the character of a washer or plate comprising a hole for freely receiving rod 1 and adapted to abut against the upper end of the lower tube section 23 with its external periphery. As is apparent, rod 1 has such a limited length that its upper end is located below the upper end of tube 2.
When the device according to figs 7 and 8 is located in the ground, one proceeds in the following way: Initially the device is rammed into the ground and this occurs preferably by means of an impact transferring member 28 diagrammatically indicated in fig 7 and adapted to apply impacts on rod 1 by means of a lower central portion 29. The impact exerting member has further an angular circumferential flange 30 intended to abut against the abutment member 27. Member 28 is accordingly adapted to simultaneously apply impacts on rod 1 and tube 2; the device is, however, such that impact application only on tube 2 cannot occur since that could lead to premature flaring of members 21. As is apparent, the impact member is introduced into tube 2 through its open upper end.
When the device has been rammed down to the desired depth, impact member 28 is removed and instead a nut tightener is introduced into tube 2 and caused to engage with nut 22. Thereafter nut 22 is turned, which causes rod 1 and anchoring members 21 to move upwardly while the latter are successively flared outwardly and engage with surrounding soil in a manner analogous to that previously described.
The device may of course be modified in several ways within the scope of the invention. Furthermore it is to be pointed out that although the device according to the invention in simplifying purpose has been described hereinabove with reference to vertical location of the device it is of course entirely within the scope of invention to apply the device more or less inclined; in connection with slopes it may also occur that need arises to locate the device substantially horisontally.

Claims

A device for anchoring in the ground and showing two parts (1, 2) relatively movable in the axial direction and a transversally expanisble arrangement (3) adapted to be actuated for expansion upon relative movement between said parts for the purpose of anchoring the device in the ground, and that one of the parts is formed by a rod (1) whereas the other part is formed by a tube (2) surrounding the rod, whereby the expansible arrangement (3) comprises flareable members (21), which form parts of a sleeve (4) provided with cuts (5) extending along a portion of the sleeve from the upper end (6) of the sleeve towards the lower end thereof, whereby one end (8) of the tube is adapted to actuate the flareable members (21) radially beginning at their upper ends, said flareable members obtaining support from the rod at their lower ends, characterized in that the rod (1) is in connection with said flareable members (21), that the sleeve (4) together with the rod (1) is arranged to be moved in a direction towards the tube (2) for said expansion of the expansion arrangement (3), whereby said flareable members (21) are arranged to flare outwardly for penetration into the ground and in that the portions flared of the flareable members (21) are arranged to be actuated to be additionally flared outwardly by the engagement into the ground when the rod (1) is moved in said direction.
A device in accordance with claim 1, characterized in that members (9) projecting from the mantle of the tube (2) are attached to the tube (2) to stabilize the device in transverse direction by engagement into the ground.
A device in accordance with claim 1 or 2, characterized in that the expansible arrangement (3) is adapted to obtain support from the rod (1) in at least one direction (P1) along the axis of the rod whereas the tube (2) is adapted to actuate the arrangement to expand with one end (8) thereof.
A device in accordance with claim 1 or 3, characterized in that the lower end (8) of the tube (2) and/or the upper ends (6) of the flareable members (21) are formed conical to facilitate penetration of the tube in between the flareable members (21) and the rod (1).
A device in accordance with any of the preceding claims, characterized in that the rod (1) comprises a thread (17) for cooperation with a nut (22) arranged to directly or indirectly obtain support from the tube (2), whereby the rod and the tube are forcibly relatively movable by turning the nut.