Mittwoch, 30. Januar 2019

cable clamps - in other than intended use

Is it ok to use a cable clamp this way?
It seems to be a good solution but it is definitely "not intended use".

Clamps should be used THIS way:

As a matter of fact we have many clamps which are used this way since many years. Now I wanted to find out: What is the breaking load of a 10 mm clamp in axial load?

First a rough calculation: The steel quality should be minimum property class 5.8.

A clamp for a 10 mm cable has a bail with two M 8 screws which should be able to hold almost 2 tons each side (M8 has 19.000 N breaking load). This means: The breaking load should be minimum 3.8 tons.
Considering that the clamp will be wedged, crooked etc., still we should be in a range of more than 3 tons. Thats the theory.
That sounds a lot, considering the size of the clamp ... its so small.
I tested in this application:


And indeed, the breaking load was in all cases more than 30 kN. This was the weakest clamp (33 kN).



I tested 10 clamps:
All of them more than 3 tons.


The axial loaded applications have to hold less than 6 kN (worst case, normally max. 3 kN) In this case they would have a safety factor of 5 minimum.
Seems enough to me.

3 Kommentare:

  1. Ok. Entendi que colocar um cabo auxiliar fixado com grampo pesado de 1/2" ligado por um mosquetão 10mm de aço oferece a segurança necessária.
    Sendo o cabo principal de 10mm (3/8") e o auxiliar 8mm (5/16").

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  2. Thank you, Dieter Stopper for the hint: I corrected the M13 to M8. Of course a 10 mm clamp has screws M8.
    I changed the calculation.
    (Somehow I was surprised about the high calculated breaking load, but it was late in the night ...)

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  3. Nilton Anderson, Sendo o cabo principale na foto acima de 12 mm compressed e o auxiliar 8 mm.
    No teste, usei 10 mm grampo.
    In the Picture the main cable is 12 mm compressed cable.
    In the test I used 10 mm clamp.

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