TELESCOPIC COLUMN PIPE TO BE LOCATED IN THE GROUND

Abstract: A telescopic column pipe (10, 11) to be located in the ground, wherein an upper pipe element (11) is provided with a top covering (14, 15) to be disposed substantially at ground level, and is displaceably received at a smooth portion thereof in a lower pipe element. The upper pipe element has an outside screw thread (17) extending over at least part of the circumference of said pipe element. By rotating the upper pipe element this element can be moved up and down in relation to the lower pipe element solely by the cooperation of the screw thread with the surrounding ground material.

Description: TELESCOPIC COLUMN PIPE TO BE LOCATED IN THE GROUND The invention relates to a telescopic column pipe to be located in the ground, compris-ing lower and upper pipe elements, the upper pipe element of which has a thread over at least part of the circumference thereof to be displaceable axially in relation to the lower pipe element by a rotational motion. An adjustable manhole construction, comprising a telescopic pipe of the type referred to above, is described in U.S. patent specification 3 533 199, the upper pipe element forming an outside thread and being screwed into the lower pipe element, which has an inside thread, such that the level of the upper edge of the upper pipe element can be adjusted by rotating the upper pipe element in relation to the lower pipe element. In other words, the upper pipe element is screwed into or out of the lower pipe element. A drawback of this prior art construction is that surrounding material may penetrate into the thread groove of the lower pipe element so that relative rotation of the pipe elements cannot take place. Moreover, any adjustment must be made by rotating the upper pipe element in relation to the lower pipe element; no axial displacement without simultaneous rotation of the upper pipe element is possible, which means that the upper pipe element cannot follow ground movements, if any. Telescopic column pipes for use in wells of different types such as sewer wells and manholes, and in conduit valve sets, are also described previously for example in the Swedish laid open publication 7414696-0 (publication No. 384 238), the upper pipe element being provided with a top covering to be disposed substantially at ground level, and being freely displaceable in the lower pipe element. Then, the top covering is a so-called floating cover which can be raised and lowered simply by removing or compacting, respectively, material below the top covering. By this procedure it is possible to adjust without difficulties the top cover to a proper level when adjusting for example an asphalt surface of a street or road. When the top covering is in a lowered position the telescopic column pipe facilitates reconstruction of a street or road, particularly when the top covering is adjusted to a final position before the street, or road is surfaced. Moreover - and this is also important - the top covering can follow movements of the ground, if any, at settling or frost action of the ground due to the fact that the top covering is floating on the street or road surfacing. The top covering accordingly will remain at the ground level independently of ground movements, if any. Thus, with a telescopic column pipe of this construction it is not necessary normally to effect adjustments, and if this is nevertheless necessitated by street or road work, the adjustment can be made in a relatively simple manner. In the present embodiments the top covering generally is made of cast iron with a cover that can be trafficated, the top covering being connected with a plastic pipe forming part of the telescopic column pipe, by said plastic pipe being shrinked onto the top covering, or forming a neck displaceably received by a plastic pipe. It is desired that also the top covering could be made of a plastic material because it will then be considerably lighter and can be handled manually without using lifting and transporting implements as may be necessary in case of cast iron top coverings. Moreover, a top covering of plastic material can be manufactured at lower costs than a top covering of cast iron; suitable plastic materials for this purpose are available. However, the low weight of a top covering of plastic material provides drawbacks as to the function thereof because the top covering of telescopic column pipes will not follow ground movements and easily can be lifted from the proper position at ground level by frost action or other ground movements. The projecting annular flange usually provided on conventional cast iron top coverings, the purpose of which is to anchor the top covering in the ground, could be used also with a top covering of plastic material but in that case an additional drawback is that vertical adjustment of the top covering cannot be effected without digging out the top covering. Moreover, it is necessary for, the flange to rest on a fixed support so as to function as a support flange. The purpose of the invention is to make possible that also a light top covering of plastic material. is arranged as a floating top covering in order to follow ground movements, if any, and that the vertical position thereof can be adjusted without the necessity of digging out the top covering. For this purpose the telescopic column pipe according to the invention is characterized in that the outside thread of the upper pipe element is limited to a portion of said pipe element adjacent a top covering provided at the upper end thereof to be located substantially at ground level, the rest of the upper pipe element having a smooth outside surface and being inserted with the smooth portion into the lower pipe element to be displaceable axially in relation to the lower pipe element so that the upper pipe element can be displaced axially in relation to the lower pipe element by the rotational motion solely by the engagement of the thread in the surrounding ground material. In order to explain the invention in more detail reference is made to the accompanying drawings, in which Figure 1 is a perspective view of the upper end portion of the upper pipe element of a telescopic column pipe, and Figure 2 is a vertical sectional view of the upper portion of the telescopic column pipe. The column pipe shown in the drawings is located in the ground as will be seen from Figure 2 and comprises a lower pipe element 10 which can be made of plastic material and can be connected at the lower end thereof for example to a well of any type, which is not shown herein. The column pipe comprises also an upper pipe element 11 which also can be made of plastic material and is inserted into the lower pipe element 10, a resilient sealing ring 12 being provided between the pipe elements. This sealing ring allows displacement of the upper pipe element in the lower pipe element and also allows relative angling of the pipe elements. A hollow socket 13 is connected to the outside of the upper pipe element 11, and this socket too can be made of plastic material and forms a top covering rim 14 at the upper end thereof. A cover 15 which can be trafficated and preferably is made of plastic material but can be made also of cast iron as a conventional construction is supported by the top covering rim. The lower end of the socket 13 is bevelled at 16 so as not to obstruct downward movement of the pipe element 11 into the ground. It should be noted that the pipe element 11 in a modified embodiment can continue directly up to the top covering rim 14 which in that case is made integral with the pipe element 11. A composite construction as shown in the drawings accordingly is not necessary but may be preferred because the socket 13 can be combined with pipe sections cut to the desired length. The interconnection of the pipe element 11 and the socket 13 can be made in any way applied to the interconnection of elements of plastic material. On the outside of the socket 13 there is provided a helical flange 17 which forms a screw thread extending over substantially one turn and has a sharp edge. This helical flange anchors the upper pipe element 11 in the ground with the top covering 14, 15 substantially at ground level as required when the top covering is of a light construction, and also makes possible that the vertical position of the top covering is easily adjusted simply by rotating the top covering and thus the socket 13 and the pipe element 11 in one direction or the other so that the unit formed by said elements is moved up and down in relation to the lower pipe element 10 at the sealing ring 12, since the helical flange 17 functions as a screw thread .which cuts a cooperating helical groove in the surrounding ground material. To facilitate the rotation, the top covering rim 14 can have projections or recesses for engagement with a lever or bar which is used for the rotation and provides a lever arm of sufficient length in order that the necessary power can be applied manually. When a surfacing, such as an asphalt layer, on the ground surface is applied or removed it is accordingly possible to raise and lower the top covering rim 14 as may be necessary, by rotating the top covering rim and thus screwing the unit connected to said rim, up or down. The helical flange 17 should begin immediately below the top covering rim 14 and should extend over one turn but it can also extend beyond one turn. It is also possible to replace the continuously extending helical flange by a number of individual flanges, for example four flanges, distributed around the circumference of the socket 13 and being mutually spaced, said flanges being angled to a transverse plane of the socket. These flanges can extend along a helical path although this is not necessary. In this arrangement, not only the peripheral edge of the flanges but also the end edges thereof are preferably formed as sharp edges. In each of the embodiments mentioned above the flange 17 or the flanges, respectively, if several flanges are provided, function as a screw thread which provides axial displacement of the pipe element 11 and elements connected therewith, when the top covering rim 14 is being rotated, by cooperation with the surrounding ground material. When a flange or several flanges are arranged as proposed according to the invention it is not necessary that the top covering rim 14 projects from the socket 13 as shown in the drawings, to support the top covering on the ground surface. Sufficient ^ support is provided by the flange or flanges engaging the ground material, in order to make the top covering a floating covering following the movements of the ground. In the conventional telescopic column pipe having a floating top covering the upper pipe element is descending by gravity at settling in the ground or will be pressed down into the ground by the top covering being loaded when trafficated. In the column pipe of the invention the upper pipe element is positively carried along by the sinking ground material at settling due to the engagement of the flange 17 into the surrounding ground material. This is a further advantage achieved by the invention, which is of particular importance when the top covering is of a light structure as in case of top coverings made of a plastic material. Also in case of top coverings having no projecting rim the upper pipe element is securely held in the desired position by the flange 17 to move with the surrounding ground material although said pipe element is not supported on the ground surface at the upper end of the column pipe. In the manufacture of the telescopic column pipe described the socket 13 with the top covering rim 14 and the helical flange 17 can be injection molded so as to be. combined later with a suitable section of an extruded plastic pipe, but it is of course also possible, as mentioned above, that the pipe element 11 forms the top covering rim 14 as well as the flange 17, said pipe element being injection molded with these details.

Claims: CLAIMS 1. Telescopic column pipe to be located in the ground, comprising lower and upper pipe elements (10, 11), the upper pipe element (11) of which has a thread (17) over at least part of the circumference thereof to be displaceable axially in relation to the lower pipe element (10) by a rotational motion, c h a r a c t e r i z e d in that the outside thread (17) of the upper pipe element (11) is limited to a portion of said pipe element adjacent a top covering (14, 15) provided at the upper end thereof to be located substantially at ground level, the rest of the upper pipe element having a smooth outside surface and being inserted with the smooth portion into the lower pipe element to be displaceable axially in relation to the lower pipe element so that the upper pipe element can be displaced axially in relation to the lower pipe element by the rotational motion solely by the engagement of the thread in the surrounding ground material. 2. Telescopic column pipe as claimed in claim 1 wherein the thread (17) extends around the circumference of the upper pipe element (11) . 3. Telescopic column pipe as claimed in claim 2 wherein the thread (17) extends over substantially one turn around the circumference of the upper pipe element, beginning adjacent a rim (14) forming part of the top covering (14, 15). 4. Telescopic column pipe as claimed in claim 1 wherein the thread (17) forms a sharp peripheral edge.

Inventors: SKOENVALL TAGE, SKOENVALL, TAGE
Applicants: UPONOR AB
Application year: 1985
Main classification: E03F5
IPC codes: E02D29, E03F5