A DEVICE FOR LOWERING AND POSITIONING OBJECTS REQUIRING ALIGNMENT Background of the Invention Earthbound sewer systems include a varying number of wells, as well as pipes that extend between nearby wells in the system. To certain wells, a plurality of pipes are connected, which are directed at different angles from the centre of the well and one of which forms a main conduit while others form shank conduits. In connection installation of the systems, pits are dug for the wells and drains for the pipes. In order to locate the different conduits in a correct way, above all in respect of the inclination, a laser-beam instrument is usually used which is lowered into a well bottom part in an appurtenant pit in the ground, and then a laser beam is transmitted via a land drain in order to enable positioning of a conduit therein.

Within the technique in question, it is an aim to use as narrow wells as feasible, frequently of plastic. Previously, wells were manufactured throughout by rings of concrete and had a diameter of at least 1 m. By comparison with this, many mod- ern wells of plastic have a diameter of 0,4 m or 0,6 m. In such, narrow wells, it is impossible for people to get down.

For this reason, alignment of the laser-beam instrument has to take place in the bottom part of the well before a rising pipe is mounted on the top thereof ; this is something that in turn means that the appurtenant pit in the ground has to be held open until one or more conduits have been installed and exactly adjusted. If the pit in question is situated adjacent to a road, the open pit may require that the road is entirely or partly closed during a certain time. In the most narrow type of well (diameter = 0,4 m), it is furthermore difficult to move the laser-beam instrument on the whole.

It should also be mentioned that the operation by phy- sical presence of inserting and handling a laser-beam instru- ment in a wide well (diameter = 1 m or more) is objectionable and risky from a working environment point of view.

Objects and Features of the Invention The present invention aims at managing the problems that are associated with the use of laser-beam instruments in connection with the construction of systems of waste water pipes of the above-related kind. A primary object of the inven- tion is to create a device enabling lowering, positioning and taking-up of laser-beam instruments in wells independently of the diameter of the wells without any operator needing to enter the wells. An additional object is to create a device that enables displacement of the instrument inserted in a well with distinct motions between different desired settings to enable, in this way, fine-tuning of the laser beam. It is also an object to provide a device which is simple and inexpensive to manufacture, and which permits a comfortable and flexible han- dling of the laser-beam instrument into and from of the well.

According to the invention, at least the primary object is attained by the features defined in the characteriz- ing clause of claim 1. Preferred embodiments of the device according to the invention are furthermore defined in the dependent claims.

Brief Description of the Appended Drawings In the drawings: Fig 1 is a schematic, vertical section through a sewer well inside which a laser-beam instrument is shown in two different positions in connection with lowering of the instrument in the well, Fig 2 is a schematic planar view showing two nearby wells, one of which houses a laser-beam instrument, Fig 3 is a perspective view of a holder included in the device according to the invention for the laser-beam instrument, Fig 4 is a perspective view of a female member for a shaft included in the device according to the invention, Fig 5 is a perspective view of an alternative embodiment of the holder of the device according to the invention, Fig 6-8 are schematic views showing three different function positions for the female member in connection with the

application thereof on a coupling part included in the holder, Fig 9 is a side view showing the device according to figs 3 and 4 connected to a laser-beam instrument, and Fig 10 is an analogous side view showing the holder according to fig 5 connected to the instrument.

Detailed Description of Preferred Embodiments of the Invention In figs 1 and 2, numeral 1 designates a first well included in a sewer system in which also other wells 1'are included. In the example, each well includes four shank con- duits 2, which extend radially out from the centre of the well at different angles for connection with four spaced-apart wells in the system. In fig 1, the well is shown as a single pipe.

However, in practice the well is put together by a fairly low bottom part and a rising pipe applied on the top thereof, the height of which varies in dependent on the excavation depth. In order to decide the exact position for a pipe (not shown) extending between two wells 1, 1', a laser-beam instrument 3 of a conventional, commercially available type is used. The instrument consists of a house having an elongate basic shape.

At one end thereof, the instrument has an eye 4 for emission of a laser beam. At the opposite end thereof, the instrument has a character display. The functions of the instrument may be remote-controlled. In practice, the length of the instrument house amounts to about 0,35 m, i. e. slightly smaller than the smallest diameter (0,4 m) in the assortment of wells.

For lowering and positioning the instrument, a device made according to the invention is used which includes a shaft 6, as well as a holder in its entirety designated 7. The shaft 6 may advantageously be telescopically extensible and has at the lower end thereof a female member 8, as well as a hook 9.

As is seen in fig 4, the female member 8 may consist of a flat box profile which is welded or in another way attached to a sleeve 10, which in turn is applied on the lower end of the shaft 6. A front wall 11 is included in the box profile 8, which is located at a certain distance from the sleeve 10. The hook 9 is attached to the sleeve 10 and placed beside the box profile 8.

In fig 3, a first embodiment of the holder 7 is shown.

In this case, the holder includes a carrier in the form of a cross-section-wise U-shaped profile piece 12 with which a detachable clamp 13, as well as a substantially C-shaped cou- pling part generally designated 14 are connected. By tightening a screw joint, the carrier 12 together with the clamp 13 may be clamped against the outside of the instrument house in a steady fixed position. On the carrier 12, a loop or ring 15 is attached for the hook 9 on the shaft 6.

Characteristic of the coupling part 14 is that the same comprises two male members, viz. a lower, upwardly point- ing male member 16, and an upper, downwardly pointing male mem- ber 17. In practice, the coupling part may advantageously be made by bending a flat bar, this providing a vertical or upright shank 18 and two horizontal shanks 19,20, from the ends of which the male members 16,17 are bent upwards and downwards, respectively. An upper end portion designated 21 of the male member 16 may advantageously be slightly inclined in the direction outwards/upwards, as is seen in fig 3. In fig 6 is shown how the lower shank 19 is somewhat longer than the upper shank 20. This means that the lower male member 16 is somewhat further distanced from the vertical shank 18 of the coupling part than the upper male member 17. In this connec- tion, it should also be pointed out that the front wall 11 of the female member 8 is somewhat wider than each one of the male members 16,17.

Function and Advantages of the Device According to the Invention When the instrument 3 has been braced in the frame formed by the carrier 12 and the clamp 13 by means of the appurtenant screw joint, lowering of the instrument in the well 1 may be commenced. As is seen in fig 1, the clamp 13 is fas- tened in the area of one end of the instrument. In this way, the centre of gravity of the instrument is located beside the clamp. In a first step, the hook 9 of the shaft 6 is applied in the loop 15 of the holder 7, and then the shaft together with the instrument may be lowered into the well 1 in a manual way, as is shown on top in fig 1. By the centre of gravity of the

instrument being displaced in relation to the clamp 13, the elongate instrument house will be tilted in relation to the vertical line; this is something that means that the introduc- tion and displacement of the instrument in a tight well is facilitated. When the instrument has reached the bottom of the well, as is shown at the foot of fig 1, the hook 9 is removed from the loop 15, and then the female member 8 is connected to the coupling part 14. This is carried out in the steps illus- trated in figs 6-8. In fig 6, the shaft 6 is shown separated from the coupling part 14. From this state, connection is car- ried out by the female member 8 of the shaft being applied to the lower male member 16 of the coupling part. More precisely, the female member is brought down into an obliquely outward- ly/upwardly leaning position, the bent upper end portion 21 of the male member 16 facilitating the engagement. When the female member 8 has reached a bottom position, the shaft is righted to a substantially vertical position in which the upper male mem- ber 17 may engage the upper opening of the female member 8, and then the shaft together with the female member are drawn upwards until the upper end of the female member meets the upper shank 20 of the coupling part, as is shown in fig 8. In this finally connected state, not only the upper male member 17 engages the female member but also the lower male member 16, more precisely in the lower opening of the female member.

By the fact that the female member 8 as well as the two the male members 16,17 have a flat basic shape, a rigid connection is guaranteed between the shaft and the holder for the instrument. In this way, the instrument may not only be brought in the forward and backward direction, respectively, in the longitudinal direction thereof, but also be turned to dif- ferent angle positions with large accuracy. Therefore, when the instrument has reached the bottom of the well, the same may be directed towards any shank conduit and then be brought in a distance into the shank conduit ; this is something which among other things means that the risk of contamination of the eye of the instrument is minimised. When the instrument is located in the correct position, the shaft may be removed if desired.

In figs 5 and 10, an alternative embodiment is shown according to which the holder comprises a platform 22 which is

provided with a clamping means 23 for clamping the instrument on top of the platform. In the example, said clamping means consists of a tape, which in a suitable way may enclose the instrument. At the rear end of the platform 22, a coupling part 14 is arranged of same type as in the previously described embodiment. The embodiment shown in figs 5 and 10 lacks a loop for the hook of the shaft and is suitable for comparatively wide wells (diameter = 0,6 metre or more).

Feasible Modifications of the Invention The invention is not solely limited to the embodiments described above and shown in the drawings-. Thus, the device according to the invention may also be used for lowering and positioning other objects requiring alignment than laser-beam instruments. Furthermore, the design of the holder as well as appurtenant coupling part may be varied in multiple ways within the scope of the subsequent claims. The holder may, for instance, be formed for the receipt of laser instruments having a cylindrical or round basic shape instead of the parallelepi- pedic basic shape that has been exemplified in the drawings.