FR2675168A1 - Device for inserting a drainage and/or insulating screen in a trench (ditch) - Google Patents

Abstract

Method for putting in place, in a trench, a material in the form of a thin film from a feed station located above the trench and by means of a guiding box structure sliding inside the trench. Inside the box structure, the film (5) is folded up on itself along a plurality of guide devices (6, 7, 8) forming an acute angle with respect to the vertical. The sum of the angles that the guide devices and the plane in which the film is conveyed to above the trench forms with respect to the vertical is equal to 90 DEG .

Description

"Device for inserting a draining and / or insulating screen
in a trench "
The invention relates to the installation of a filtering or insulating screen made of a thin film material in a trench.

 It is known in particular from French patent 2,000,531 to proceed with the installation of such a screen by means of a vertical drum carrying the roll of film introduced into the trench behind the excavating machine which digs the trench, the film being directly unwound at its service location as the excavator progresses, the roller and the enclosure which contain it being connected to this machine.

 The Dutch patent 82.04737 teaches the integration of such a roller in a sliding box in the trench at the rear of the excavator.

 It is known in another way to supply the screen material with film from a roller disposed above the trench and moving at the same time as the excavating machine, means of return being provided in the trench for passing the film from the substantially horizontal plane which is hers above the trench to a vertical plane which corresponds to its service position in the trench.

An example of such a device is described in German patent 30.12.980
Whatever the mode of distribution of the film material, either by a drum located above the trench, or by a drum housed in the trench itself, the film necessarily passes inside the trench by a guide box sliding behind the excavator or the machine making the trench, and whose walls are in contact with those of the trench itself.

 This results in frictional forces which oppose the progression of the machine and which are all the more important the deeper the trench and the longer the box.

 The present invention aims to solve this drawback and to minimize the length of the guide box so as to reduce these friction forces, while keeping the box a narrowness which makes it suitable for use in narrow trenches.

 According to the invention, the film being supplied from means arranged above the trench is guided in the trench along a plurality of return cylinders arranged at an acute angle with the vertical, the sum of the angles of said cylinders of reference and of the film supply plan above the trench being equal to 900.

 In this way, the film passes from a practically horizontal position or close to the horizontal above the trench to a vertical position in the trench with a displacement in the horizontal direction of value less than the width of the film. As a result, the box for introducing and guiding the film in the trench may have a length much less than the width of the film.

 Preferably, but without this being a limitation of the invention, the film is folded three times on itself along three return cylinders inside the box.

 Also preferably, the film drum or reel is disposed above the trench at an angle of inclination directed rearward relative to the direction of advancement.

 According to another advantageous characteristic, the return cylinders are mounted in the box so that the angle they make with the vertical can be adjusted.

This multiple folding process of the film insertion position in the trench provides many advantages, including
- it makes it possible to limit the length of the box to
a value less than the width of the film, and
so can be used on machines
weak power,
- it allows to keep a small width of the
box which makes the process suitable for being
used in narrow trenches and allows
to accept passages in low curves
Ray,
- it allows an easy connection of the film between
two coils outside the trench,
- it allows the use of film reels of
significant lengths, the latter being
stored outside the casing not posing any
space constraints.

The invention will be better understood with the aid of the description below of an embodiment given without limitation of the laying process with reference to the appended drawings in which
Figure 1 is a schematic elevational view of a site for laying a film in a trench using the method according to the invention.

 Figure 2 is a schematic elevational view of the path of the film according to the invention from its supply reel to its service position in the trench with the folds provided by the method according to the invention.

 FIG. 3 is a diagrammatic elevation view of the folding of the film according to the invention with identification of the folding angles, corresponding to the drawing in FIG. 2.

 Figure 4 is a schematic perspective view of a first embodiment of the maintenance of the film on the edge of the trench by means of nails.

 Figure 5 is a schematic perspective view of a second embodiment of maintaining the film on the edge of the trench by means of a special comb.

 Figure 6 is a schematic perspective view of a third embodiment of the maintenance of the film on the edge of the trench by means of a spiral wire.

 In a manner known per se, the trench is produced by means of an excavator or chainsaw machine such as a crawler machine carrying a steerable excavator chain or a machine driving an excavator wheel.

 For simplicity, there is shown schematically an excavating chain 1 which digs a trench 2.

 Behind the chain excavator 1 is hitched a box 3 which slides on the bottom of the trench 2. The box is open at its upper part and has a rear vertical opening for film output.

 Above the trench 2 a drum 4 or a reel for feeding a thin film material 5 is carried by the machine. This material can be insulating or draining as required.

 In the example shown, the drum with axis O is inclined rearward relative to the direction of movement A by an angle 1 of approximately 55 "relative to the vertical.

 At the outlet of the drum 4, the film 5 is folded back with respect to the direction of advance A, passing around a fixed guide cylinder 6 mounted in the box 3.

 The cylinder 6 makes an angle a2 of approximately 10 with the vertical.

 The film then passes around a second substantially vertical fixed cylinder 7 disposed towards the rear of the box with an angle 3 of approximately 15 relative to the vertical.

 The film 5 is then folded forward relative to the direction of advance A.

 Then the film 5 passes around a third substantially vertical cylinder 8 disposed near the front of the box and making an angle a4 of approximately 10e with the vertical. It is folded back around this last roller and then leaves the box through the rear vertical opening previously described.

 Of course at the start of construction, the free end of the film will be fixed in the trench by any appropriate means so that the only movement of the excavating machine will be enough to ensure the unwinding of the film in the vertical plane inside the trench. .

 After the film has unfolded, the trench is filled after possibly having been paid with gravel, by means of a hopper 15 carried by the box 3.

 Optionally, a draining collector 16 can be introduced into the trench in a manner known per se.

 In the example shown, with the indicated values of the angles of the return cylinders 6, 7 and 8 and of the feed drum 4, the film 5 is passed from its horizontal position outside the trench to its vertical position inside the trench over a distance substantially equal to half the width L of the film 5.

 The diagram in FIG. 3 shows the angles (a2, a3, 4) of the successive folds of the film with respect to the vertical and the references (P1, P2 and P3) correspond to the axes of the respective return guides (6, 7 and 8 ).

 In FIG. 1, it can be seen that the folding of the film according to the invention makes it possible to limit the length of the box 3 for inserting the film 5 into the trench 2 to around half the height of the trench. This compactness of the insertion box makes it possible to provide for its association with also very compact means for the establishment of a draining tube, the pouring of loose materials to fill the trench and possibly the arrangement of a backfill disc. An example of such an auxiliary box 17 is schematically represented in dotted lines in FIG. 1 with its chute 18 for the passage of a draining tube 16 and its hopper 15 for discharging bulk products.

 At the rear, this auxiliary box is provided with an arm carrying a backfill disc 19 intended to cover the trench 2 with a layer of earth.

 In the example above, we have described the return of the film 5 in the box 3 by means of independent fixed cylinders arranged in the box 3. However, it would be possible, without departing from the scope of the invention, to guide the film in the box by any other means such as grids or slots made in inclined partitions inside the box, which has the advantage of increasing the rigidity of the box and therefore of building it with lighter materials.

 One can, according to another embodiment, use conical rotating cylinders instead of fixed cylinders.

 Of course, one could provide a greater number of folds of the film inside the box without departing from the scope of the invention.

 Advantageously, it is also possible to provide means for guiding the film 5 during its passage over the cylinders 6, 7, 8 when the latter are rotary, whether motorized or not. For example, one can provide on the upper and lower edges of the film 5 perforation lines intended to engage on corresponding pins of the cylinders, in the manner of what is known for driving photographic film.

 Advantageously, the invention provides special means for maintaining the film in the correct position in the trench before the latter is filled.

 Indeed, the film, once unwound in the trench because of its flexibility and thinness, tends to crumple and sag. To overcome this drawback, it has already been proposed to keep the film in place on the edge of the trench by means of simple nails.

 An exemplary embodiment of such a nailing is shown in Figure 4 in which we see that the film 5 inserted in the trench 2 is provided with an upper edge folded and nailed to the edge of the trench by the nails 9. Optionally , the upper edge of the film 5 is provided with perforations 10 which can serve as a guide for driving in the nails or as a passage for the holding devices which are shown in FIGS. 5 and 6.

 In FIG. 5, it can be seen that the film 5 is held in place by a comb 11, the teeth 12 of which pass through the holes 10 in the upper edge of the film 5 and are closed on the opposite edge by a bar 13 which is deposited on the end of the teeth 12.

 In FIG. 6, it is a wire 14 with large spirals passing through the holes 10 of the film 5 which maintains the film on the upper edge of the trench.

 In the case of FIGS. 5 and 6, the combs 11 or the wire 14 also serve as a device for warning of the presence of the film during a subsequent earthmoving operation during which the earth covering the trench would be removed.

Claims (11)

 1. Method for placing a thin film material in a trench from a feeding station arranged above the trench and by means of a sliding guide box inside the trench , characterized in that inside the box the film (5) is folded on itself along a plurality of guide devices (6,7,8) forming an acute angle with respect to the vertical and in that the sum of the angles made by the guiding devices and the film feed plane above the trench with respect to the vertical is equal to 90 ".  2. Method according to claim 1, characterized in that the film (5) is folded three times inside the box.  3. Method according to claims I and 2, characterized in that the film supply plane (5) forms with the vertical an angle (1) of about 55, the first guide device (6), an angle ( a2) with the vertical of about 10, the second guide device (7), an angle (3) with the vertical of about 15 and the third guide device (8) an angle (4) of about 10.  4. Method according to any one of claims 1 to 3, characterized in that at the rear of the sliding box, the film is held on the edge of the trench using nails (9).  5. Method according to any one of claims 1 to 3, characterized in that at the rear of the sliding box, the film is held on the edge of the trench by means of combs 11 whose teeth 12 pass through perforations 10 made in the upper edge of the film and are closed by a bar 13.  6. Method according to any one of claims 1 to 3, characterized in that at the rear of the sliding box, the film (5) is held on the edge of the trench (2) by means of a spiral film (14).  7. Device for implementing the method according to any one of claims 1 to 6, characterized in that the devices (6,7,8) for guiding the film (5) inside the box are cylinders fixed.  8. Device according to claim 7, characterized in that the cylinders (6,7,8) are mounted in the box by means making it possible to adjust the angle which they make with the vertical.  9. Device for implementing the method according to any one of claims 1 to 6, characterized in that the film guiding devices inside the box are constituted by slots made in inclined partitions.  10. Device for implementing the method according to any one of claims 1 to 6, characterized in that the guiding devices (6, 7, 8) of the film (5) inside the box (2) are rotating conical cylinders.  11. Device according to claim 10, characterized in that the film (5) has on its upper and lower edges of the perforation lines cooperating with pins provided on the cylinders (6, 7, 8).