The present invention concerns a compression indicator. It also concerns a method of using an indicator clip as compression indicator.
The indicator is to be used with a compression unit of a frame for cable entries, cable transits or pipe penetrations. The cable entries, cable transits or pipe penetrations have the form of modules that are compressed around the cable or pipe in order give a tight seal. Normally a number of modules are received inside the frame together with a compression unit, placed to compress the modules. Furthermore, partitions are often placed between modules at different levels within the frame.
In the compression unit it is common to have one or more screws or the like, which are turned to give the desired compression. Many suppliers of compression units stipulate a certain torque with which the screws or the like should be drawn to give a desired compression. However, in such a case there is no swift and easy way to control the compression afterwards.
When mounting and installing cable entries, cable transitions or pipe penetrations, it is often up to the skill of the installer to get the correct compression. It is often important to avoid a too high compression as well. Normally the screws have a stop hindering that they are screwed out too far.
The present invention is developed for compression units having screws to control the compression. The compression unit may have the form of a wedge. Such a wedge normally has interacting parts with oblique contact surfaces, whereby the interacting parts move in relation to each other, increasing or decreasing the outer dimension of the compression wedge. The screws of the compression wedge are screwed outwards, i.e. the distance between the screw head and the compression wedge is increased to increase the compression force. Thus, the distance between the screw head and the compression wedge is an indicator of the applied compression force.
There is a need for a method of controlling the compression, which method should be easy to apply and not involve too high costs. According to the invention, the compression is controlled by placing an indicator clip on the stem of one or more screws of the compression unit. The width of the indicator clip is adapted to the desired compression. If the available space is not enough to be able to place the indicator clip on the one or more screws, the compression should be increased until the indicator clip can be placed on the one or more screws.
It is possible to mark the indicator clips in different ways, by colour, letters, numbers and other signs. The different markings may of course be used together in different ways. By such marking it is possible to identify the person responsible for the control of the compression and/or the installation of cables and/or pipes.
The frames of the described kind are often placed in relatively harsh environments. The indicator clips are therefore also formed to protect the threads of the screws in some extent from dust, mud etc.
Depending on the requirements of the different installations it is possible to use indicator clips having different widths. If the requirements are less severe, the applied compression force may be less than for more sensitive installations.
The invention will described more closely below by way of examples and with reference to the enclosed drawings. In the drawings:
In the example of
The present invention is directed to compression units 3 having a design that is such that the compression is increased the further the screws 4 are screwed out of the compression unit. Thus, the compression increases when a distance A from the compression unit 3 to the screw head increases (see
To control the distance indicator clips 6, 8, 10, 12, 14, 16 have been designed in accordance with the present invention. The widest part of each indicator clips 6, 8, 10, 12, 14, 16 is adapted to the desired minimal distance A between the compression unit 3 and the head of each screw 4.
The clip 6 of
The ends 7, 9, 11, 13, 18 of the indicator clip 6, 8, 10, 12, 14, will to some extent cover the threads of the screws 4 and protect them from dust or other dirt. The exact design of the indicator clips 6, 8, 10, 12, 14, 16 may vary as long as they fulfil the intended function of controlling the compression. In
The part of the clip between the ends may have the same width as the ends (
The rounded ends 7, 9, 11, 13, 18 normally have the form of a part of a circle, often a semicircle, seen in side view. The part of the circle has an extension of at least 45°, preferably at least 90° and most preferred at least 180°. The radius of the part of the circle is adapted to the size of the stem of the screw 4 on which the respective rounded end 7, 9, 11, 13, 18 is to be received. In some embodiments a rubber gasket or coating is placed inside the rounded ends, thus, between the rounded ends 7, 9, 11, 13, 18 and the screws 4.
The angles α, β at which the ends 7, 9 are placed in relation the central parts of the indicator clips 6, 8 of
Even tough the indicator clip 14 of
The compression clip is normally made of plastic or aluminium and may be produced by any suitable method, such as extrusion or moulding.
Some compression wedges have only one screw. For that type of compression wedges the indicator clip 16 has only one rounded part 17, to be placed around the stem of the screw. Furthermore, it has a straight, level part placed at a distance above the rounded part.
In use the compression clip 6, 8, 10, 12, 14, 16 is placed on the screws 4 of the compression unit 3. If the distance between the compression unit 3 and the head of each screw 4 is too small to receive the rounded parts of the indicator clip 6, 8, 10, 12, 14, 16, the screws 4 should be screwed out further until the indicator clip 6, 8, 10, 12, 14, 16 can be received. If the indicator clip 6, 8, 10, 12, 14, 16 cannot be received the compression of the compression unit 3 is not at the minimal predetermined compression. On the other hand if the available space for the indicator clip 6, 8, 10, 12, 14, 16 is much larger than the width of the indicator clip 6, 8, 10, 12, 14, 16, it is an indication that the compression unit 3 may have been compressed to much and that the screws should 4 be screwed inward to decrease the compression.
In alternative embodiments the clips have a somewhat different design. In the example of
In the embodiment of
Number | Date | Country | Kind |
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0600420-4 | Feb 2006 | SE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/SE2007/050105 | 2/22/2007 | WO | 00 | 10/13/2009 |