WO1993018253A1

WO1993018253A1 - Mast base

Info

Publication number: WO1993018253A1
Application number: PCT/NO1993/000037
Authority: WO
Inventors: Tom Toralv RØYNESTAD
Original assignee: Roeynestad Tom Toralv
Priority date: 1992-03-12
Filing date: 1993-03-10
Publication date: 1993-09-16
Also published as: NO920959D0; NO920959L

Abstract

One has aimed at providing a rational method for the construction of a mast/pole base comprising a socket plate (5) having means (7) for the attachment of the mast/pole (9), e.g. through a bottom plate (8) rigidly connected to the mast/pole (9), whereby - at the same stability and mechanical strength - is achieved substantial time and cost savings over prior art technique which comprises digging, planking and casting. For this object, at least one substantially vertical hole (2) is predrilled into the ground (1), for at least one perforated base pipe (3), which thereafter is driven down into the predrilled hole (2), whereafter the base pipe is casted to the ground through supplying concrete, preferably under pressure, through the base pipe's (3) upper open end extending above ground level, so that the concrete partially is pressed out through said perforations (4) of the base pipe (3), for thereby more or less to fill out the remaining spaces between the inner wall of the hole (2) predrilled into the ground (1) and the external mantle face of the base pipe, whereafter said socket plate (5) is fixed to the top end portion of the base pipe (3). A mast/pole base for use when carrying out the method described, comprising a socket plate (5) having means (7) for the attachment of a mast/pole (9), e.g. through a bottom plate (8) rigidly connected to the mast/pole (9), distinguishes itself by comprising at least one perforated base pipe (3), and in that the socket plate (5) has a fixture (6) for its unshakable fixing on the upper base pipe end portion.

Description

MAST BASE

The present invention relates to a method for making a mast/ pole base, as well a mast/pole base made by means of the method.

When one today makes a mast/pole base, e.g. for masts/poles for current carrying conductors for trains, one digs into the ground a hole of about 2 x 2 metres to a depth of about 1,5 metres, whereafter a formwork is made for the casting of a base. When the base has been poured, a further formwork is built on the top thereof for a mast/pole socket having four casted-in bolts for the anchoring of the mast/pole itself. The work is very time-consuming and consequently extremely expensive.

In accordance with the present invention, one has aimed at providing a method for making a mast/pole base, as well as a mast/pole base made by means of this method, representing substantial time- and cost-savings over prior art technique, so that one rapidly and with simple and cheap means may establish a mast/pole base having at least as high a stability and mechanical strength as known mast/pole bases having corresponding dimensions.

According to the invention, said objects are realized through proceeding in accordance with the method defined in the following method claim, respectively through, designing the mast/pole base in accordance with the following apparatus claims.

For large and heavy masts/poles, four base pipes are used according to the invention, while for more slender masts/ poles fewer base pipes may be used, e.g. only one single base pipe.

Thus, the invention consists substantially in predrilling at least one vertical hole into the ground for a perforated base pipe, which thereafter is driven into the predrilled vertical hole.

For the predrilling and driving-down operations, a known drilling rig, of the type may be used, e.g. av the type used in rock drilling, in that the driving of the base pipe takes place by means of the drill hammer.

The pipe is thereafter possibly cut. When several pipes are involved, the cutting is effected such that the resultant top pipe ends become situated at the same level, for thereby to balance possible mutual irregularities in predrilling and/or driving.

To the top pipe portion respectively the top pipe portions, a socket plate having anchoring means for a mast/pole is thereafter clamped.

Thereafter, the pipe respectively the pipes may be reinforced, in that e.g. cam steel bars are guided into the pipe bore from above, whereafter concrete is filled into the pipe respectively the pipes.

The filling of concrete takes preferably place under pressure, to that the concrete partially is pressed out through said perforations of the base pipe respectively pipes and penetrates into the space between the external mantle face of the base pipe and the internal face of the ground defining the predrilled hole. When the concrete within said space hardens (it is integral with the concrete column within the pipe through the perforations), a secure casting of the base pipe within the ground is established, said base being capable of withstanding substantial loads.

A mast/pole base according to the invention distinguishes itself by comprising at least one perforated base pipe assigned a socket plate equipped with a fixture for unshakable anchoring of the base pipe/pipes and having means for secure attachment of the bottom end of a mast/pole or similar column.

Said fixture may be formed with cooperating clamps, preferably one fixed and one movable clamp, having opposing clamp faces the circumference of which does not follow a semi-circle but only a shorter arc of a circle. Such a design enables compensation for irregularities caused by inaccurate placement of the pipes in the ground. If the base comprises e.g. four pipes, said design of the fixture will enable withdrawal of the pipes if they are not quite accurately placed in the ground.

An example of two embodiments is further explained in the following, reference is being made to the accompanying drawings, wherein:

Figure 1 shows a side elevational view of a one-pipe mast/ pole base, with a vertical section through the ground in the area of a predrilled vertical hole for driving/casting of the base pipe;

Figure 2 shows a horizontal section of the same mast/pole base along the line II-II in figure 1;

Figure 3 shows a four-pipes mast/pole base (only two base pipes are visible in that the other two are hidden behind the two first-mentioned), shown in side view with a vertical section through the ground in the area of the predrilled holes;

Figure 4 is a top plan view of the socket plate, wherein the four base pipes are fixed between the clamps of the fixture;

Figure 5 corresponds to figure 4 but shows the fixture in another position, namely wherein the respective clamps are brought into the position they occupy when the socket plate is fit down over the four base pipes, i.e. with the clamps in inactive pipe-accommodating position;

Figure 6 shows in side elevational view the socket plate according to figure 1 but with the fixture in the position as shown in figure 5.

First, reference is made to figures 1 and 2 illustrating the invention in the simplest embodiment thereof.

According to figure 1, a vertical hole 2 has been predrilled in the ground for a base pipe 3 formed with^' through-going (radial) perforations 4 which are to allow a later peneration of concrete into the space between the external mantle face of the base pipe 3 and the internal face of the ground 1 defining the predrilled hole 2.

The predrilling and driving of the base pipe 3 may advantageously be performed by means of a conventional drilling rigg, e.g. of the kind used in drilling of rock. After the base pipe 3 has been driven down into the predrilled hole 2, the pipe 3 may be reinforced by means of reinforcing iron, e.g. cam steel, which simply are inserted into the bore of the pipe 3. Thereafter, concrete is filled into the top end of the pipe 3, the filling of concrete preferably taking place under pressure, in order to promote the tendency of the concrete to penetrate the perforations 4 of the pipe 3 and fill the space between the predrilled bore wall 2 and the external mantle face of the base pipe 3. Hereby, an efficient reinforcing and rigid casting of the base pipe 3 are achieved.

Before or after the casting, the top end of the pipe may be cut, so that the pipe end becomes situated at a desired level for the fixing of a socket plate 5 having a fixture 6 comprising clamps to be further explained in association with figures 3 - 6.

The socket plate 5 is provided with means, e.g. bolt holes 7, for the attachment of a bottom plate 8 which in the embodiment is formed integral with a mast/pole 9.

In figures 3 - 6, the fixture 6 of the socket plate 5 is shown more in detail. In these figures, parts corresponding to parts 1-8 according to figures 1 and 2 are denoted with the same reference numerals, even if the fixture 6 of the socket plate 5 in figures 3 - 6 comprises two clamp devices, each for fixing two base pipes 3.

The fixture 6 of the socket plate 5 appears best from figures 4 - 6, wherein said two clamp pair are denoted 10, 10' and 11,11' . Each clamp 10,10' ,11,11 ' is formed with two grooves 10a,10a', 11a, 11a¹ for the accommodation of somewhat less than half the cross-section of the associated base pipe 3, i.e. the respective groove's circumferential shape does not follow a semi-circle but rather a shorter arc of a circle, corresponding to abot 60-70 degrees. Such a design has been found to give a more suitable fixing of the base pipe, especially if it is somewhat out of plumb.

One clamp 10' and 11' of each pair of clamps 10,10' and 11, 11' is rigidly connected to the socket plate 5, e.g. by means of bolts or welding.

It is to be noted that it in practice has proved advantageously to arrange the outer clamp 11' of the pair of clamps 11,11" fixed and the inner displaceable, see figure 5 in connection to figure 4, while the opposite is the case for the pair of clamps 10,10', wherein the inner clamp 10' is fixedly connected to the socket plate 5, while the outer clamp 10 is displaceably supported and may move towards and away from the fixed inner clamp 10' .

The movable clamp 10 respectively 11 is displaceably supported in relation to the fixed clamp 10' respectively 11' by means of through-going bolts 12 having a fixed nut or head 13 and a tightening nut 14.

In one clamp 10 respectively 11' of each pair 10,10' respectively 11,11', in the area of the grooves 10a,10a', 11a,11a' for the base pipes 3, is formed a threaded bore 15 for a set screw (not shown) for fixing the associated base pipe 3. In lieu of such set screws one may use through-going bolts (not shown) extending through corresponding bores in the clamps and holes through respective base pipe 3.

In figures 4 - 6 appear the socket plate's holes 7 for bolting of the bottom plate 8 of the mast/pole 9 as well as a through-going hole 16 for conduits, not shown.

Claims

C l a i m s

1. A method for constructing a mast/pole base comprising a socket plate (5) provided with means (7) for the attachment of the mast/pole (9), e.g. through a bottom plate (8) rigidly connected to the mast/pole (9), c h a r a c t e r i z e d i n predrilling at least one substantially vertical hole (2) into the ground (1) for at least one perforated base pipe (3), which thereafter is driven down into the predrilled hole ( 2 ) , whereafter the base pipe (3) is casted fixedly to the ground through the supply of preferably concrete, by preference under pressure, through the base pipe's (3) upper, above ground level extending, open end, so that the concrete partially is pressed out through said perforations (3) of the base pipe (3), for more or less to fill out remaining spaces between the inner wall of the predrilled hole (2) in the ground and the external mantle face of the base pipe, whereafter said socket plate (5) is fixed to the upper end portion of the base pipe (3 ) .

2. A method as set forth in claim 1, c h a r a c t e r i z e d i n that, especially when the mast/pole base comprises more than one base pipe (3), e.g. four such pipes ( 3 ) , the pipe ends are cut in order to bring the resultant top end faces to be situated at the same level.

3. A method as set forth in claim 1 and 2, c h a r a c t e r i z e d i n that in the base pipe respectively in each base pipe (3), prior to the filling of concrete, one or more reinforcing rods are inserted, e.g. cam steel, in order to reinforce the pipe/concrete-assembly.

4. A mast/pole base for use when carrying out the method defined in one or more of the preceding claims, comprising a socket plate (5) having means (7) for the attachment of a mast/pole (9), e.g. through a bottom plate (8) rigidly connected with the mast/pole, c h a r a c t e r i z e d i n that the mast/pole base comprises at least one perforated base pipe (3), and that the socket plate (5) has a fixture (6) for the unshakable fixing thereof on the top base pipe end portion.

5. A mast/pole base as set forth in claim 4, c h a r a c t e r i z e d i n that the fixture ( 6) of the socket plate (5) comprises at least a pair of clamps (10,10' and/or 11,11'), of which one fixed and one movable clamp of each pair are formed with arch-like grooves ( 10a,10a' , 11a, 11a¹ ) forming two opposing clamp faces for clamping respective base pipe ( 3) .

6. A mast/pole base as set forth in claim 5, c h a r a c t e r i z e d i n that each arch-like groove (10a,10a¹ ,11a,11a' ) has a central, substantially circle arch-like portion the periphery of which extends over an angle substantially less than 180 degrees, i.e. that each groove has a circle arch-like course substantially less than a semi-circle.

7. A mast/pole base as set forth in one or more of the claims 4 - 6, c h a r a c t e r i z e d i n that the clamps of the pair of clamps ( 10, 10' ,11, 1 ' ) respectively each pair of clamps are connected with each other by means of through-going bolts (12) which partly serve as fixing means, partly as guides for the displaceable clamp (10,11) in relation to the fixed clamp (10* ,11').

8. A mast/pole base as set forth in any one of the preceding claims 4 - 7, c h a r a c t e r i z e d i n that in one pair of clamps (10,10') the outer clamp (10) is movably arranged in relation to the fixed inner clamp (10' ), while. at the opposite side of the sockel plate (5), the inner clamp (11) is movably arranged in relation to the fixed outer clamp (11' ).