The present invention relates to a method and an apparatus for pulling electrical conductors into an elastically bendable protection pipe so that both ends of the conductors are available outside the pipe after the pulling operation, while the intermediate longitudinal portion of the conductors lies protected within the protection pipe. The invention also relates to a pulling rope for carrying out the method.

Upon conventional installation of electrical conductors in a socalled concealed wiring in e.g. a house building, a ship, etc. , bendable protection pipes of plastic material are mounted in a first working operation. In a second working operation, a pulling rope is pushed through each installed protection pipe length (e.g. between two connection boxes) , so that the pulling rope, except its two end portions, is entirely occluded within the protection pipe length. In a third working operation, a desired number of conductors are fastened to one available end portion of the pulling rope by means of a clamp or a similar, easily releasable anchor means. Thereafter, by exerting a pulling force at the opposite end portion of the pulling rope, the conductors are pulled into the protection pipe until they substantially

occupy the same position within the pipe that the pulling rope occupied previously.

Pushing the pulling rope into the pipe is often associated with problems, and the working operations are in part cumbersome and time-consuming, substantially because of the fact that they have to be carried out at the place of work. At the building site, it is rarely possible to erect an apparatus facilitating the pulling of the conductors into the pipes, this work being conducted manually without any mechanical auxiliary means. If the leading end of the conductors get stuck within the protection pipe length, one has no other opportunity than pulling the conductors back and try once more.

In recent time, protection pipes have come to light (see e.g. European patent publication No. 0038273 and Norwegian patent application No. 933823) , said protection pipes through a pulling rope have been provided with internally positioned conductors in the production phase. Such protection pipes with inserted electrical conductors having end portions projecting from the ends of the protection pipe may have a length of e.g. 100 metres individually, may be coiled up on reels/drums which, thereafter, may be placed within special boxes (confer NO patent application No. 943716) serving as holders/carriers for reels or drums with protection pipes with internal conductors, coiled up thereon. The present invention is not concerned with such carrier boxes, but with methods and apparatus for inserting a pulling rope and, thereafter, pulling conductors into the protection pipe, as well as a special shape and design of a pulling rope's portion.

With very long protection pipe lengths, it is practically not possible to push a pulling rope into and through the pipe, and in these cases it has, therefore, been usual to place a pulling rope within a protection pipe during the manufacturing thereof which, to a substantial extent,

complicates and, thus, increases the price of the protection pipe manufacturing. Such a pulling rope inserted into position during the production of the protection pipe, can not be reused. The alternative to this way of inserting the pulling rope into long protection pipes is, based on the state of the prior art, to exert a pressing force on the pulling rope in a direction pointing to the end of the protection pipe opposite the end wherein the pulling rope's leading end was inserted in the first place. This is quite impossible in protection pipes for internal conductors having a standard production length, e.g. 100 metres. But even with substantially shorter protection pipe lengths, it has been found impossible to push a pulling rope through the pipe. In Norwegian patent application No. 933823, it is, consequently, suggested to place a pulling rope into each protection pipe during the production phase therefore, complicating the pipe making and the apparatus for carrying out the method.

EP 0038273 discloses an apparatus for pulling conduits into flexible pipes. Here, it is suggested to push a pulling rope through each flexible pipe, but these pipe lengths are relatively short, in any case substantially shorter than the production lengths of the order of about 100 metres, which forms the basis for the making of protection pipes having conductors included therein and which are coilable on reels or drums.

A main object of the invention has, consequently, been to provide a method and an apparatus, as well as a special shape and design of the pulling rope, securing an insertion of the latter into the protection pipe, said pulling rope in inserted condition extending in the full length extent of the protection pipe, preferably exceeding said length extent such that end portions of the pulling rope project outside the protection pipe ends, in order to facilitate said conductors anchoring to one projecting pulling rope end portion in a manner known per se, and wherein favourable conditions are offered for bringing the pulling rope into the protection

pipe in a particularly rational and efficient way both with a view to the method and the apparatus for carrying out the method, and wherein the pulling rope is shaped and designed in order to facilitate the carrying out of the method. By a special treament of a portion of the pulling rope, it should be possible to further facilitate the implementation of the method, the production length of the protection pipes at all times being of the order 100 metres.

In accordance with the invention, said objects are realized by (a) proceeding according to the following claims directed to said method respectively (b) by means of the special constructive building up of the apparatus respectively c) by means of the special shape and design of the pulling rope.

A pulling rope shaped and designed in accordance with the present invention is released subsequently to finished use in the immediate neighbourhood of the apparatus which is adapted with a view to pull in a pulling rope in a first operation and to pull in the conductors through the pulled in pulling rope, and such a pulling rope is adapted for reuse; this in opposition to known pulling rope inserting methods and apparatus wherein the pulling rope is placed within each protection pipe during the production thereof. Of course, such known pulling ropes are not fit for reuse. Naturally, one may take care of all such (inserted upon production) pulling ropes after use and try to reuse them, but this is not consistent with a rational production. On the other hand, the term "reuse" means that one and the same pulling rope may be used successively for pulling in conductors in one protection pipe after the other, and such a use of a "common" pulling rope is consistent with a rational production, such it will appear from the following description of the method respectively the mode of operation of the apparatus according to the invention.

In accordance with the invention, the leading end of the pulling rope has a thickening in the form of a head adapted

to be accommodated in one end of the protection pipe as a piston movable in one direction, establishing a degree of sealing in respect of the internal mantle face of the pipe that is consistent with a problem-free movement through the protection pipe from the pulling rope-insertion end thereof to its opposite open end when - at the latter pipe end - a suction effect is exerted based on vacuum/negative pressure acting on the end face portion of the pulling rope head facing towards the last-mentioned protection pipe end.

This suction effect in combination with the shape and design of the pulling rope enable the pulling of a pulling rope into and through a protection pipe having a substantial longitudinal extent, e.g. about 100 metres.

One can facilitate the pulling rope head's suction into/ through the protection pipe by applying a sliding-favouring liquid on the head. The head may be of a porous, liquid- absorbing material such that it can be saturized with sliding agent. How high a degree of sealing that should be established between the pulling rope head and the internal mantle face of the protection pipe, is dependent on the available suction force.

In the method for pulling conductors into an elastical protection pipe, it may be suitable for the achievement of a rational production to place each of a plurality of protection pipes along a U-shaped course, the ends thereof situated laterally adjacent each other in a common horizontal plane, easily releasably anchored by clamps or other fasteners, such that a first, innermost U-shaped protection pipe's ends are located in the immediate neighbourhood of each other, while a second protection pipe, the end portions thereof diverging more away from each other than the first protection pipe's end portions, surrounds the first pipe laterally and at the U-bend; a third protection pipe bended into U-shape surrounding the second pipe laterally and at the U-bend, the end portions of said third pipe diverging more

from each other than the second pipe's diverging end portions, and so on. The anchoring clamps for the third (or last) protection pipe's ends are, thus, located laterally outside the remaining clamps. When treating e.g. three protection pipes simultaneously as described, each having a length of about 100 metres, each pipe during the treatment exhibiting two parallel portions, 50 metres each, united by said U-bend, the apparatus according to the invention will be equipped with six aligned clamps or the like. If these are numbered l through 6 from a first end to the last one, the third, outermost protection pipe's ends will be assigned clamps 1 and 6, the intermediate pipe's ends clamps 2 and 5 , and the first (the innermost) pipe's ends clamps 3 and 4. In such an arrangement of two or more protection pipes, the need of space in the longitudinal direction is reduced by about 50%, simultaneously as their ends become lying very conveniently aligned and directed parallelly (all ends facing one operator) , in order to offer favourable conditions for rational production.

A number of protection pipes can be brought into this U-shaped position (course) in order to receive first a pulling rope and, thereafter, through the intermediary of the pulling rope, the conductors which, thereafter, become lying permanently within the respective protection pipe and, together with this one, consistutes one product, which is coiled up on a reel, from where pipe with internally placed conductors can be uncoiled and cut to appropriate lengths at the building site.

The positioning of several protection pipes simultaneously in stationary position each substantially following an U-shaped course, ready for successively receiving first a common (reused) pulling rope and, thereafter, through the inserted pulling rope, the conductors belonging thereto, may be carried out in the apparatus according to the invention by means of a drive wheel and a turning or guide wheel spaced from the former (e.g. about 50 metres), each wheel having a

vertical rotational axis. An endless rope- or tape-shaped protection pipe-feeding member surrounds the two wheels. The rope-shaped feeding member in the form of e.g. a wire carries a dog having an easily releasable fastener for several pipe ends. When the endless wire moves by means of the drive wheel, it pulls with it said dog with the pipe ends attached thereto, first in a direction towards the turning/guide wheel, then around the same and, thereafter, in a direction towards the drive wheel, the wire and, thus, the dog and the protection pipe ends being stopped when the pipe ends have reached the correct position. Thererafter, the wire with its dog becomes inactive and may, if so desired, be demounted until this first set of protection pipes are provided with the electrical conductors belonging thereto.

Thereafter, the protection pipes are cut. If the pipes are positioned outside each other in the same plane, the first (innermost) protection pipe needs a shorter length than a further outside positioned U-shaped protection pipe, in order to fasten the ends by means of said stationary clamps, but all pipes bended into intermediate U-shape will be cut to approximately the same length, independent on positioning, this being in consistency with a rational productionprocess. It is also feasable that a bundle consisting of a plurality of protection pipes in height and width is coupled to the carrier (dog) of the wire. If the spacial conditions allow, said turning or guide wheel may, if necessary, be positioned outside the production hall. The industrial building's adjacent external wall must in such a case be provided with a narrow horizontal slot for the passage of the pipes laterally past each other in two opposite directions.

With the protection pipe ends attached in said aligned clamps, jaws or other easily releasable anchoring means, a common pulling rope with said thickening is passed into e.g. said first (innermost) protection pipe's one end opening. The thickening exhibits a lateral measure adjusted to the protection pipe diameter, so that only a minimum leakage

takes place along faces of thickening and internal pipe face mutually resting against each other.

According to the invention, to the same (first, innermost) protection pipe's other end is coupled a suction hose connected to a source of negative pressure, e.g. in the form of a vacuum pump. When the pump is activated, the pulling rope thickening and, thus, the pulling rope are sucked through the pipe, until the thickening reaches the coupling mouthpiece of the suction hose which may have a narrowed portion, in order to prevent the pulling rope thickening from being sucked too far into the suction hose which, thereafter, is disengaged from the protection pipe end. Then, the vacuum pump is deactivated, whereafter the desired/necessary number of conductors are pulled into the protection pipe by means of the pulling rope inserted therein. The latter pulling operation may be effected in a manner known per se, but also this working step is, preferably, carried out in an efficient and labour-saving way according to the invention.

The pulling rope should have a length from end to end which to an adequate extent exceeds the longitudinal extent of a protection pipe, so that - when the pulling rope is pulled into a protection pipe - a free end portion of the pulling rope will project from each end of the protection pipe, the thickening of the pulling rope being located at or in the neighbourhood of one end thereof.

According to the invention, the one ends of the electrical conductors are attached to the projecting pulling rope end portion, opposite the thickening.

When the one ends of the desired number of electrical conductors have been fastened to the free end portion of the pulling rope, opposite the thickening, the pulling rope is passed into driving engagement with said drive wheel, which is activated for rotation, pulling the pulling rope forwardly, thus effecting that said conductors are pulled into the

protection pipe. The drive wheel may be assigned a smaller idler wheel, the wheels together forming a nip through which the pulling rope is intended to pass and through which it is fed by means of said drive wheel. As soon as a sufficient free pulling rope portion has passed said nip,as counted from the thickening, the latter is immediately inserted into one end of protection pipe No. two, the other end thereof being coupled to the connecting mouthpiece of the suction hose. This represents a rational production step of the method according to the invention: While the common pulling rope is in the course of pulling electrical conductors into a first protection pipe, the very same pulling rope is simultaneously in the course of being sucked into a second protection pipe, the manufacturing process being continued in this way.

An example of a possible embodiment of an apparatus adapted to provide elastical protection pipes with electrical conductors inserted therein is further explained in the following, reference being made to attached drawings, wherein:

Figure 1 shows a top plan view of an apparatus for pulling electrical conductors into several (six) protection pipes, and illustrates especially a device included in the apparatus and adapted to shape protection pipes having a length of the order 100 metres to occupy a temporary U-shape, the pipe ends in positions ready to be anchored in clamps or the like placed in alignment with each other in the lateral direction of the apparatus, so that the openings of the pipe ends are facing towards the operator, and where one support point for the protection pipes is defined by said clamps, their second, common support point being constituted by said turning or guide wheel, contributing in shaping each pipe into a U;

Figure 2 shows the apparatus of figure 1 as seen in top plan view, the protection pipes occupying their positions for receiving an inserted pulling rope and, thereafter, through

the inserted pulling rope, a number of conductors, and illustrates especially the common pulling rope's thickened end immediately prior to its insertion into a pipe's one end opening, this pipe's other end being coupled to a suction hose, in order to suck the pulling rope's end thickening through the pipe, i.e. until the thickening of the pulling rope reaches the other end of the pipe. As mentioned, said pulling rope shall have a longitudinal extent exceeding the length of a protection pipe;

Figure 3 corresponds to figure 2, but here the pulling rope is pulled entirely into a first protection pipe, and to one end thereof is coupled a number of conductors desired to be placed within this protection pipe;

Figure 4 corresponds to figure 3, but here the ends of the conductors, through the intermediary of the pulling rope, are pulled partly into the protection pipe by means of the drive wheel, the thickening of the pulling rope occupying a position for immediate insertion into one end of the next protection pipe, the mouthpiece of the suction hose already being coupled to the other end of the last-mentioned pipe;

Figure 5 corresponds to figure 4, but here electrical conductors are pulled partly into said next pipe, so that the foremost portion of the pulling rope has been released to enable the insertion of the thickening into the one end of pipe number three, the other end of which being coupled to the mouthpiece of the suction hose;

Figure 6 shows a situation where electrical conductors are in the course of being pulled into the last but one of the shown set of six pipes, the pulling rope being in the course of being sucked through this pipe, and where the last pipe of this set has been coupled to the mouthpiece of the suction hose;

Figure 7 shows a number of protection pipes inserted into

a common collection pipe having a diameter sufficient to accommodate all of the protection pipes.

First, reference is made to figure 1, illustrating how a set of pipes - here comprising six protection pipes 10a, 10b, 10c, 10d, lOe, lOf - is placed in U-shape in a common horizontal plane, ends 10a', 10a", 10b', 10b", 10c', 10c", 10d ^» , lOd", 10e', 10e", 10f, lOf" aligned, figure 2, forming a lateral row extending right-angledly to the longitudinal axis of an apparatus for pulling electrical conductors into the elastical protection pipes, the end openings thereof facing towards an operator, in the longitudinal direction of the apparatus, in order to facilitate the working operations.

The apparatus according to the invention comprises a drive wheel 12 and a turning or guide wheel 14 spaced therefrom, e.g. 50 metres, each wheel 12, 14 being assigned a vertical rotational axis. As previously explained, the turning wheel 14 may be positioned outside the production hall, the adjacent external wall thereof in this case being provided with a horizontal slot for the passage of the pipes lOa-lOf in two opposite directions. The turning wheel 14 is assigned lateral restricting walls 14' .

Around the drive wheel 12 and the turning wheel 14 is placed an endless conveyer means 16, e.g. in the form of a wire. The endless conveyer wire 16 has a carrier or dog 18 which may be articulated to the endless conveyer wire 16, and which comprises a holder 18' with fasteners (not shown in detail) for a number, e.g. six, protection pipes lOa-lOf. The drive wheel 12 is put into rotation, and the carrier 18 becomes pulled in the direction towards the turning wheel 14 by means of the conveyer wire 16, then partly around the turning wheel 14 and, thereafter, back in the direction towards the drive wheel 12, which may be assigned an idle wheel 20 forming a pressure nip with the drive wheel 12. When the protection pipes lOa-lOf are brought to occupy this U-shaped horizontal position (course) , the drive wheel 12 is deactivated, and

the conveyer 16 may, possibly, be demounted.

In order to bring the pipes to follow this U-shaped course and occupy these positions temporarily, the pipes may alternatively be pulled through a U-shaped pipe 37, figure 7, having a diameter that is sufficient for the pipe 37 to accommodate all protection pipes lOa-lOf of a set. This pipe 37 may have its two mouths spaced relatively shortly from the clamp. When using such a pipe 37, the turning wheel 14, 14' may be omitted. The pipe 37 may be positioned outside the production hall proper.

Thereafter, the twelve ends 10a', 10a", lOb ¹ , 10b", IOC, 10c", 10d', lOd", 10e', lOe", 10f, lOf" of the six protection pipes lOa-lOf are attached, e.g. in pairs, in clamps or similar clamping means 22a, 22b, 22c, 22d, 22e, 22f or the like or other easily releasable fasteners adapted for temporary anchoring of the pipe ends.

Reference numeral 24, figures 2-6, denotes a pulling rope which is common for the pulling operations and which has a thickening in the form of a head or piston 26 at one end thereof. This pulling rope 24,26 should have a length allowing the working operation e.g. as illustrated in figure 6 to be carried out, and where the thickness 26 of the pulling rope 24 occupies a position spaced from the insertion end of the outermost protection pipe, the pulling rope 24 extending along most of the length extent of pipe number five. The pulling rope 24 is fed between the fifth pipe's lOe one end and one end of the sixth pipe lOf by means of the drive wheel 12.

This pulling rope 24 with its thickening 26 can be inserted into one or the other of any one of the protection pipes. In order to systematize the pulling operations, they can be started at the innermost pipe ends 10a', 10a" and continued outwardly as the pulling rope 24,26 is released.

In figure 2, the thickening 26 of the pulling rope 24 is in the course of being inserted into one end 10a' of the protection pipe 10a, a mouthpiece 30 of a suction hose 28 is threaded tight-fittingly onto the pipe end 10a". The suction hose 28 is coupled to a source of negative pressure, e.g. a vacuum pump 32. The pulling rope's 24 thickening 26 is, as already explained, adapted to the pipe bore, and a sliding agent/lubricant may be applied thereon. The suction effect from a moderate vacuum pump 32 has been found to be sufficient to suck a pulling rope 24 with its thickening 26 according to the invention very rapidly through a protection pipe lOa-lOf with a length of 100 metres.

At its mouthpiece 30, the suction hose 28 is formed with a narrowed portion 34, the passage thereof being narrower than the pulling rope thickening's 26 cross-sectional area, so that the thickening 26 is brought to stop there when the pulling rope 24 has been pulled into the pipe 10a, whereafter the vacuum pump 32 is stopped. Now, from the pipe end 10a' it will project a pulling rope portion enabling the operation illustrated in figure 3, where the pulling rope thickening 26 is in the course of being passed into the pressure nip between the drive wheel 12 and its assigned idle wheel 20, and where to the trailing end of the pulling rope 24 are attached the ends of the electrical conductors 36a, 36b, 36c which are desired to be pulled into the protection pipe 10a in order to lie permanently protected therewithin subsequently.

According to figure 3, the suction hose mouthpiece 30 is already coupled to the end 10b" of protection pipe (number two) 10b, but such a coupling operation may wait until the pulling rope 24 has been pulled through and out of the pipe 10a by means of the drive wheel 12 and, with its thickening 26, is inserted into the pipe end 10b ¹ , figure 4 showing the situation immediately before this happens, and where the conductors 36a-36c are pulled a distance into the first protection pipe 10a.

The working operation steps are repeated until all six protection pipes lOa-lOf are provided with their respective internally disposed conductors 36a-36c.

Thus, figure 5 shows a situation where the first (innermost) protection pipe 10a is provided with three pulled-in conductors 36a-36c, the end portions thereof projecting outside the ends 10a', 10a" of the pipe 10a; the pulling rope 24,26 being in the course of insertion into the third protection pipe's 10c end 10c', while the suction hose mouthpiece 30 is coupled to the last-mentioned pipe's 10c other end 10c", a portion of three other conductors 36a'-36c' being pulled into the second protection pipe's 10b end portion 10b' .

Figure 6 shows a situation where one is in the course of approaching the termination of the conductor pulling into the shown set of six protection pipes.

Here, four protection pipes 10a, 10b, 10c and lOd are provided with their respective conductors 36a-36c, 36a'-36c', 36a"-36c" and 36a' ' '-36c• • ^« , conductors 36a""-36c"" being in the course of being pulled into fifth protection pipe lOe, while the foremost portion with the thickening 26 of the pulling rope 24 is on its way in a direction towards the turning wheel 14 within the outermost protection pipe lOf, and where the suction hose mouthpiece 30 is coupled to the sixth protection pipe's lOf end lOf".

Protection pipes of the kind with which the present invention is engaged, may be used for protective encapsulation of cables and conduits, but also for pressure fluid hoses for hydraulic/pneumatic plants.