Norwegian patent 302546 concerns a method and a device for mechanized drawing of one or more electrical cables into a sheathing tube. In the method according to NO 302546, the free end portions of the sheathing tubes located on a reel are first placed in a carrier. The carrier is connected to a continuous wire and is designed to pull the sheathing tubes through a first straight distance before it is reversed about a reversing wheel with a vertical axis, pulling the free end portions of the sheathing tubes back to the area in which they were connected to the carrier. The sheathing tubes are cut into appropriate lengths, whereupon the end portion of each sheathing tube is releasably connected to its respective fastening clamps. Thus the sheathing tube forms a U-tube extending from a first fastening clamp, about the reversing wheel to a second fastening clamp, and is thereby ready for drawing of electrical cables.

For the method of drawing electrical cables into the sheathing tube, reference is made to NO 302546.

Experience has shown that the sheathing tubes may get tangled during the drawing process, necessitating a time-consuming sorting operation before the end portions of the sheathing tubes can be placed in the respective fastening clamps.

According to prior art, it is not possible to pull a new set of sheathing tubes forward until all the sheathing tubes from the previous pull-up have been removed from the drawing device. Thus prior art requires all sheathing tubes from one draw-in set to be completed before the next set of sheathing tubes can be drawn in. This disadvantage causes an unfavourable interruption of the operation of drawing electrical cables into corresponding sheathing tubes. When one set of sheathing tubes is finished, this operation must be interrupted until a new set of sheathing tubes has been drawn into the drawing machine.

The object of the invention is to remedy the disadvantages of prior art.

The object is achieved in accordance with the invention, by the characteristics given in the description below and in the appended claims.

Placing the free end portion of the sheathing tubes horizontally side by side in a draw carriage, which runs in a trough, allows the sheathing tubes to be drawn into the drawbench without any risk of twisting/tangling.

The draw carriage is connected to drive means that in addition to a load-carrying frame construction also comprises a horizontal-axis drive drum, a horizontal-axis reversing drum and at least one draw wire or similar belt-like element.

In a preferred embodiment a draw wire extends from each side member of the draw carriage, about the two drums and back to the corresponding side member of the draw carriage, where there is provided a tensioning device for imparting the required tension to the wires. Thus the carriage and the drive and reversing drums together constitute drive means arranged continuously to move the carriage along the straight sections and around the drums. Preferably the drive and reversing drums are provided with peripheral tracks for the draw wires.

The draw carriage is equipped with first and second sets of wheels. The first set of wheels is arranged for rolling movement along the bottom of the upper trough, up to the reversing drum. After the carriage has reversed about the reversing drum the second set of wheels is rollingly moved along the bottom of a lower trough.

Preferably a number of attachment tubes for releasable coupling of the end portions of the sheathing tubes to the draw carriage is connected equidistantly to the draw carriage along its transverse extent. The longitudinal axes of the attachment tubes are at right angles to the direction of travel of the carriage.

By giving the side opening of the lower trough an appropriate design it is possible to draw a new set of sheathing tubes into the drawbench before the drawing of all the lengths of sheathing tube from the previous set is finished and these have been removed from the drawbench.

Beyond prior art, the device according to the invention exhibits an ordered drawing of new lengths of sheathing tubes into the drawbench. Moreover, the device will essentially allow the production to run continuously.

In the following, a non-limiting example of a preferred embodiment is described, which is illustrated by the accompanying drawings, in which: Figure 1 shows a side view of a drawbench where the draw carriage and the drive means are shown during the movement of the draw carriage in the upper trough; Figure 2 shows the same as figure 1, but here the draw carriage is reversing around the reversing drum ; Figure 3 shows the same as figure 1, but here the draw carriage is being moved in the lower trough; Figure 4 shows a section I-I in figure 1; Figure 5 shows a section IV-IV in figure 4; and Figure 6 shows a view V-V in figure 5 of an attachment tube.

In the drawings, reference number 1 denotes a drawbench placed on a floor 2. The drawbench 1 comprises a load- carrying frame structure 4, a drive drum 5 driven by a drive motor (not shown), a reversing drum 6, a draw carriage 8, an upper trough 10 and a lower trough 12.

The drive drum 5 and the reversing drum 6 are arranged on separate end portions of the drawbench 1, with rotational axes in the horizontal plane and perpendicular to the longitudinal extent of the drawbench 1. The drums 5,6 are rotationally supported on the frame structure 4 and are provided with wire pulleys 14 at their respective ends. The diameter of the middle section of the drums is reduced relative to the wire pulleys 14. Two draw wires 16 extend between the respective wire pulleys 14 of the drums 5,6.

The free end portions of the draw wires are connected to the respective side members 18 of the draw carriage 8 in a manner that is known per se. The draw carriage 8 is arranged to follow the path of the draw wires 16 upon rotation of the drums 5,6.

The upper trough 10 and the lower trough 12 are connected to the frame structure 4, extending between the drums 5,6 along the entire longitudinal extent of the drawbench 1.

The draw carriage 8 is equipped with a first set of wheels 20 and a second set of wheels 22. The first set of wheels 20 is designed to rollingly abut the bottom of the upper trough 10 when the draw carriage 8 is located in the upper trough 10.

The second set of wheels 22 is designed to rollingly abut the bottom of the lower trough 12 when the draw carriage is located in the lower trough 12.

Transversely across the draw carriage 8 there are eight attachment tubes 24 fixed to the structure 26 of the draw carriage 8 and distributed equidistantly along the transverse extent of the draw carriage 8. The longitudinal axis of the attachment tubes 24 is perpendicular to the transverse direction and direction of travel of the carriage.

The free end portions of the sheathing tubes 28 to be drawn into the drawbench are displaced into their respective attachment tubes 24, the attachment tubes 24 being arranged to releasably hold the sheathing tubes 28. The sheathing tube 28 may be corrugated.

At one end portion, corresponding to the end portion at which the sheathing tube 28 is displaced into the attachment tube 24, the attachment tube 24 is provided with a constriction 30. The constriction 30 is formed by deforming the end portion of the attachment tube 24 to form a chord-shaped profile 32. The chord-shaped profile 32 is designed to be able to grip the outside corrugation of the sheathing tube 28.

When a set of sheathing tubes 28 is to be drawn into the drawbench, e. g. from reels of sheathing tube (not shown), the free end portions of the sheathing tubes 28 are placed in the corresponding attachment tubes 24, where the constriction 30 causes the sheathing tube 28 to be held in the attachment tube 24. The drive motor (not shown) of the drawbench 1 is started up, whereby the drive drum 5 is rotated, moving the draw carriage 8 by means of the draw wires 16, along the upper trough 10 in the direction of the reversing drum 6, see figure 1. The free ends of the sheathing tubes 28 are thereby drawn by the draw carriage 8 into the drawbench 1.

As the draw carriage 8 is pulled onto the reversing drum 6, it simultaneously leaves the upper trough 10 and is rotated about the reversing drum 6, see figure 2, until it is pulled into the lower trough 12.

The draw carriage 1 is then moved along the lower trough 12, see figure 3, until the draw carriage 1 approaches the drive drum 5. The end portions of the sheathing tubes 28 are released from the attachment tubes 24, whereupon they may be fastened to appropriate fixtures for drawing of electrical cables (not shown) into the sheathing tubes 28.

The design of the drawbench 1 allows one set of sheathing tubes 28 to be drawn into the drawbench 1 before all the sheathing tubes 28', see figure 4, from the previous drawing have been removed. The sheathing tubes 28'from the previous drawing are located on the opposite side of the structure 26 of the draw carriage 8 relative to those sheathing tubes that are in the process of being drawn, thus constituting no obstacle to the draw carriage 8 during the drawing of a new set of sheathing tubes 28.

Drawing of a set of sheathing tubes 28 into the drawbench 1 may be carried out without risk of tangling the sheathing tubes being drawn in, as the drawing takes place with the sheathing tubes 28 mainly abutting the bottom of the upper trough 10, the reversing drum 6 and the bottom of the lower trough 12.

The U-shaped path according to the invention is also space- saving when seen in relation to prior art.