WO2002007280A1

WO2002007280A1 - Multiple expander

Info

Publication number: WO2002007280A1
Application number: PCT/GB2001/003145
Authority: WO
Inventors: Thilo Simonsohn
Original assignee: Tyco Electronics Raychem Gmbh; Tyco Electronics Uk Limited
Priority date: 2000-07-15
Filing date: 2001-07-12
Publication date: 2002-01-24
Also published as: AU2001269335A1

Abstract

A device (1) for applying a radially expandable and recoverable sleeve (12) on an elongate article (11) is arranged for expanding the sleeve upon insertion of the elongate article (11). The device (1) comprises a first unit (1a) and a second unit (1b), the units having first and second radially expandable section (5c, 5b) respectively, the second expandable section (5b) being insertable in the first expandable section (5a) and preferably allowing sequential expansion and/or recovery.

Description

MULTIPLE EXPANDER

The present invention relates to a device for applying a sleeve on an elongate article, such as a cable or a rod. More in particular, the present invention relates to a device for applying a radially expandable and recoverable sleeve on an elongate article having an outer cross-sectional dimension greater than the largest inner cross-sectional dimension of the unexpended sleeve, the device being arranged for expanding the sleeve.

The problem of expanding an elastic sleeve and applying it on an elongate article while expanded is well known. German patent DE 474 991 published in 1929 already provides a device for expanding elastic sleeves. This known device comprises a set of four tongues or "needles" which can be inserted into a sleeve and which can then be pushed apart by a hollow rod. A cable can then be passed through the rod and through the expanded sleeve held open by the needles. A disadvantage of this known device is that its structure does not permit expansion over a large range, involving large forces. In addition it is difficult to remove the device from relatively long sleeves.

Another approach is disclosed in International patent application WO 89/00782 where it is suggested to insert a plurality of longitudinally extending rails into a sleeve to be expanded, after which a cable is pushed through the sleeve, the inserted rails allowing the cable to slide and thus expand the sleeve. A disadvantage of this approach is that a plurality of separate elements, that is the rails, have to be inserted into the sleeve prior to expansion and that it is difficult to control these elements during expansion. In addition, all these elements have to be removed when the sleeve has been applied.

European patent application EP 0 815 624 proposes to mutually connect the sliding elements by a cross-strap, thus making it easier to insert and remove the elements. The individual elements, however, may still easily break off the cross-element connecting the sliding elements. It is an object of the present invention to eliminate these and other disadvantages of the prior art and to provide a device for applying a sleeve onto an elongate article, which device is easy to insert into and remove from the sleeve, even if the sleeve is relatively long.

It is another object of the present invention to provide a device for applying a sleeve on an elongate article which consists of a small number of components.

It is a further object of the present invention to provide a device for applying a sleeve on an elongate article which facilitates the initial expansion of the sleeve

It is a yet further object of the present invention to provide a method for applying an elastic sleeve on an elongate article.

To meet these and other objects, a device as defined in the preamble is according to the present invention characterised in that the device comprises a first unit and a second unit, the units having first and second radially expandable section respectively, the second expandable section being insertable in the first expandable section.

By inserting two expander units into the same sleeve several advantages may be obtained. Firstly, the force required for expanding the sleeve may be distributed over the expandable sections, decreasing the chances of damaging these sections (for example constituted by flexible fingers). Secondly, the first and second expandable sections may have different shapes, allowing a locally varying expansion. Thirdly, the first and second expandable sections may have different lengths, which may facilitate the insertion and/or removal of the device.

In a preferred embodiment, therefore, the second expandable section has a shorter length than the first expandable section. More preferably, the length of the second expandable section is approximately half the length of the first expandable section. To facilitate an easy insertion of the elongate objects into the expander units, preferably the units are at one end provided with first and second widened sections respectively.

The expandable sections may be constituted by longitudinally extending and substantially flexible fingers. In a particularly advantageous embodiment, however, at least one expandable section comprises a longitudinally extending and radially expandable tube.

To allow pre-expansion of the sleeves, a device according to the present invention may further comprise at least one substantially rigid tube insertable in the first and second units. Preferably, such a device comprises a first and a second substantially rigid tube, the first tube having a smaller diameter than the second tube so as to be insertable therein. To allow an easier handling of these expander tubes, preferably the second tube has a smaller length than the first tube. The tubes ("holdouts") are preferably inserted one after the other so as to obtain a gradual expansion requiring relatively little force.

To facilitate the expansion process, the first tube may be provided with a tapered nozzle which is preferably removable. Additionally, or alternatively, the second tube is provided with a tapered adaptor, the adaptor having a through hole for passing through the first tube.

The present invention also provides a method of applying a radially expandable and recoverable sleeve on an elongate article having an outer cross-sectional dimension greater than the inner cross-sectional dimension of the unexpanded sleeve, the method comprising the step of inserting into the sleeve a device arranged for expanding the sleeve, which method is characterised by inserting into the sleeve a first expander unit and subsequently a second expander unit, prior to inserting the elongate article into the two expander units.

On recovery, the expander units may be removed together or one after the other. Any expander tubes ("holdouts") used are preferably both inserted and removed one after the other. The present invention will further be explained below with reference to the accompanying drawings, in which:

Figure 1 schematically shows, in cross-sectional view, a device according to the present invention inserted into a sleeve; Figure 2 schematically shows, in cross-sectional view, the device of Fig. 1 where the sleeve is partially expanded;

Figure 3 schematically shows, in cross-sectional view, the device of Fig. 1 where the sleeve is fully expanded.

Figure 4 schematically shows, in partial cross-section, a single expander unit inserted in a sleeve.

Figure 5 schematically shows, in cross-section, a first holdout tube provided with a nozzle.

Figure 6 schematically shows, in cross-section, a second holdout tube provided with a conical ring. Figure 7 schematically shows, in partial cross-section, the holdout tube of Fig. 5 inserted in the expander unit of Fig. 4.

Figure 8 schematically shows, in partial cross-section, the insertion of the holdout tube of Fig. 6 into the arrangement of Fig. 7.

Figure 9 schematically shows, in partial cross-section, the removal of the conical ring after completion of the insertion of Fig. 8.

Figure 10 schematically shows, in partial cross-section, the arrangement of Fig. 9 after the removal of the first holdout tube.

Figure 11 schematically shows, in cross-section, how the front edges of the holdout tube of Fig. 6 may be formed.

The device 1 shown merely by way of non-limiting example in Fig. 1 comprises a first expander unit la and a second expander unit lb. Each unit consists of an expandable section

2a, 2b and a widened, non-expandable section 4a, 4b. The expandable sections 2a, 2b each consist of flexible, longitudinally extending fingers connected by the widened sections 4a and 4b respectively. As shown in Fig. 1, the fingers 5 of the first expandable section 2a extend over approximately the full length of the sleeve 12, whereas the fingers of the second expandable section 2b are much shorter and extend over only approximately half the length of the sleeve

12. This will further be explained below.

The first widened section 4a is, in the example shown, shorter than the second widened section 4b. In addition, it has a larger diameter so the second widened section 4b can be inserted into the first widened section 4a. Each widened section 4a, 4b is provided with a radially extending flange 5a, 5b.

Also shown in Fig. 1 are first and second expansion tubes or "holdouts" 20a, 20b. These are substantially rigid tubes, for example made from hard plastic or metal. Inserting these tubes into the expander units enables pre-expansion of the units and the sleeves they are inserted in, as shown in Figs. 2 and 3. The elongate article (e.g. cable 11) on which the sleeve in question has to be applied can then be inserted in the tube 20, after which the tube and the expander units are pulled out, allowing the sleeve to recover on the elongate article.

Instead of using holdout tubes having different lengths but similar diameters, it is also possible to use holdout tubes having dissimilar diameters. Such tubes may be used in conjunction with two expander units, as shown in Figs. 1-3. However, it is also possible to use two (or more) expander tubes having different diameters in conjunction with a single expander unit 1 as shown in Fig. 4.

Figure 5 shows an expander tube ("holdout tube") 20a provided with a nozzle 21. The nozzle has a tapered part 22 for pushing apart the fingers 5 of the expander unit 1 and a mounting part 23 for mounting on the expander tube 20a. As shown in Fig. 5, the mounting part has a slightly reduced diameter which fits inside the tube 20a. A ridge 24 acts as a stop and defines the position of the nozzle 21 relative to the tube 20a. In the embodiment shown the nozzle 21 is removable so as to allow a cable or other elongate article to be passed through the tube 20a. The expander tube 20b shown in Fig. 6 has an outer diameter D which is substantially larger than the outer diameter d of the tube 20a of Fig. 5. Preferably, D is between 10% and

100% larger than d. To bridge the different diameters and to allow a smooth expansion the tube 20b is provided with an adaptor 25, which essentially consists of a conical ring. The adaptor 25 has a tapered part 26, a through hole 27 and a mounting part 28. The latter is shaped like the mounting part 23 of the tube 20a but has a larger diameter. The through hole

27 has at least a diameter d to allow the tube 20a of Fig. 5 to pass through.

The tube 20a of Fig. 5 will also be referred to as "inner tube" as it can be inserted into the tube 20b of Fig. 6, which may in turn be referred to as "outer tube".

In use, the inner tube 20a is first inserted into the expander unit 1 of Fig. 4, thereby expanding the sleeve 12. In this first step, the inner diameter of the sleeve is expanded to (d+x), where x is the thickness (height) of the fingers 5 of the expander unit 1. After expanding the sleeve 12 over its full length, the nozzle 21 is removed, as shown in Fig. 7.

Subsequently, in the second step, the outer tube 20b is inserted into the expander unit 1, thereby further expanding the sleeve 12. As shown in Fig. 8, the adaptor 25 provides a smooth diameter transition and thereby facilitates the expansion process. In addition, the adaptor 25 assists in controlling the movement of the outer tube 20b as the adaptor is guided by the inner tube 20a. In this step, the inner diameter of the sleeve 12 is expanded to (D+x), where x is the thickness of the fingers 5 as before. After further expanding the sleeve 12 over its full length, the adaptor 25 is removed, as shown in Fig. 9. It is noted that the flange 29 of the outer tube 20b abuts the rim of the expander 1 when the expansion is completed.

Subsequently the inner tube 20a is removed, as shown in Fig. 10. The expanded sleeve 12 can now be applied on an elongate article, or can be stored in its expanded state for later use.

Instead of, or in addition to providing an adaptor 25, the edge 30 of outer tube 20b may be bevelled off to decrease friction. The edge may have a sloping straight surface, such as the edge 30', or be rounded, such as the edge 30". Although the invention has been explained above with reference to a two-step expansion process, it is very well possible to use three or even more steps, each step involving the use of another holdout tube preferably having different dimensions. For example, three holdout tubes having increasing diameters could be used in conjunction with one, two or even three expander units. In all cases the step-wise expansion results in reduced forces, enabling manual expansion even for relatively large ranges of expansion.

Further advantages may be achieved by a device according to the present invention characterised by a plurality of fingers or other longitudinal elements having at least one substantially concave side.

By providing longitudinal elements having a concave side, it is possible to apply a lubricant on said side without it being immediately removed by any sliding motion. The lubricant is substantially contained between the resulting longitudinal protrusions and will lubricate over substantially the entire length of the sleeve. In this way, the friction is considerably reduced and the application of a sleeve using the device is greatly facilitated.

In an advantageous embodiment the longitudinal elements are substantially flat, that is, the elements have a substantially rectangular or oval basic cross-section, at least one side being at least slightly concave to carry any lubricant. Preferably both sides of the elements are concave to facilitate their use and to eliminate any erroneous use.

The elements may be mutually connected to constitute a single, possibly even integral device. However, it is possible for the elements to constitute separate parts.

This aspect of the present invention will now further be explained with reference to the accompanying Figure 12 in which sliding elements 3 have an approximately rectangular cross-section. However, the "outer" surface is shown to be concave, while the "inner" surface is shown to be substantially flat. The terms "inner" and "outer" refer to the substantially circular arrangement of the sliding elements 3 within the sleeve (not shown) in use, the "outer " surfaces facing the inside of the elastic sleeve. The concave shape of the outer surface results in protrusions 6 to extend along the length of each element 3.

Lubricant may be applied to facilitate the insertion of the elements 3 into, and the removal from, the sleeve, in which case the lubricant is laterally contained by the protrusions 6.

In addition, the protrusions 6 take up some of the pressure exerted by the sleeve, thus preventing the lubricant from being squeezed from the element 3.

It will be understood that instead of a curved, concave surface a substantially straight outer surface having upstanding protrusions 6 could be used with the same or a similar effect, and is therefore included in the term "substantially concave".

Although the elements may be separate, as disclosed in the preceding Figures, they may also be combined into a single, possibly even integral device along the lines shown in Fig. 12. This device 1 comprises a flexible tubular expander element 2 having reinforcement ribs 3 constituting the sliding elements. In accordance with the present invention, the reinforcement ribs 3 are substantially concave on the outside of the tubular expander element. Such an embodiment has the advantage that the spacings between the sliding elements 3 are well defined and that the sliding elements 3 cannot overlap under high pressure.

When individual sliding elements 3 are used (mutually connected by a connecting element, such as a ring) care should be taken to avoid overlapping of the sliding elements 3 upon expansion of the sleeve.

It will be understood by those skilled in the art that the present invention is not limited to the embodiments shown and that many additions and modifications are possible without departing from the scope of the present invention as defined in the appending claims

Claims

1. Device (1) for applying a radially expandable and recoverable sleeve (12) on an elongate article (11) having an outer cross-sectional dimension greater than the largest inner cross-sectional dimension of the unexpanded sleeve, the device being arranged for expanding the sleeve, characterised in that the device (1) comprises a first unit (la) and a second unit (lb), the units having first and second radially expandable sections (5a, 5b) respectively, the second expandable section (5b) being insertable into the first expandable section (5a).

2. Device according to claim 1, wherein the second expandable section (5b) has a shorter length than the first expandable section (5a).

3. Device according to claim 2, wherein the length of the second expandable section (5b) is approximately half the length of the first expandable section (5a).

4. Device according to any of the preceding claims, wherein the units (la, lb) are at one end provided with first and second widened sections (4a, 4b) respectively.

5. Device according to claim 4, wherein the first widened section (4a) has a greater diameter than the second widened section (4b).

6. Device according to claim 4 or 5, wherein the first widened section (4a) has a smaller length than the second widened section (4b).

7. Device according to claim 4, 5 or 6, wherein each widened section (4a, 4b) is provided with a radially extending flange (15a, 15b).

8. Device according to any of the preceding claims, wherein at least one expandable section (5 a, 5b) comprises longitudinally extending and substantially flexible fingers (9).

9. Device according to any of the preceding claims, wherein at least one expandable section (5a, 5b) comprises a longitudinally extending and radially expandable tube.

10. Device according to any of the preceding claims, further comprising at least one substantially radially rigid tube (20) insertable in the first and second units (l , lb).

11. Device according to claim 10, comprising a first and a second substantially rigid tube (20a, 20b), the first tube (20a) having a smaller diameter than the second tube (20b) so as to be insertable therein.

12. Device according to claim 10, wherein the second tube (20b) has a smaller length than the first tube (20a).

13. Device according to claim 11 or 12, wherein the first tube (20a) is provided with a tapered nozzle (21) which is preferably removable.

14. Device according to claim 11, 12 or 13, wherein the second tube (20b) is provided with a tapered adaptor (25), the adaptor having a through hole (27) for passing through the first tube (20a).

15. Device according to any preceding claim characterised by fingers or other longitudinally extending elements having at least one substantially concave surface to accommodate a lubricant in a position to lubricate the removal of the sleeve when present.

16. Method of applying a radially expandable and recoverable sleeve (12) on an elongate article (11) having an outer cross-sectional dimension greater than the largest inner cross- sectional dimension of the unexpanded sleeve (12), the method comprising the step of inserting into the sleeve (12) a device (1) arranged for expanding the sleeve (12), characterised by inserting into the sleeve (12) a first expander unit (la) and subsequently a second expander unit (lb), prior to inserting the elongate article (11) into the two expander units (la, lb).

17. Method according to claim 16, wherein the second expander unit (lb) only expands part of the sleeve (12).

18. Method according to claim 16 or 17, further comprising the step of inserting at least one rigid expansion tube (20) into the expander units (la, lb) prior to inserting the elongate article (11).

19. Method according to claim 16, 17 or 18, wherein the expander units (la, lb) are removed after applying the sleeve (12) on the elongate article (11).

20. Method according to claim 18 or 19, wherein two tubes (20a, 20b) having different diameters (d, D) are used, the first tube (20a) being insertable into the second tube (20b).

21. Method according to claim 19 or 20, wherein at least one tube (20a, 20b) is provided with a tapered nozzle (21) or an adaptor (25).

22. Method according to any of claims 16 to 21 , wherein a decide according to any of claims 1 to 15 is used.