Cord Configurations in Steel Cord Belts
Not all manufacturers build steel cable belts using the philosophy.
Sempertrans France (S.F.B.T.) use a steel cable belt construction where they standardize to only a few cord diameters for their belts and increase and decrease the spacing of the cords to achieve a different tension ratings. They call this construction Metalcord.
Their M-cord is a more elastic and forgiving cord than a traditional ST-cord. The M-cord has a stretch of 0.6%. Their E-cord was 0.2% stretch.
Conventional steel cord belts use the rubber between the cords and surrounding the cords for lateral support. S.F.B.T. adds elastic (3.25%) transverse steel breaker cables for lateral support allowing them to eliminate much of the gap between the cords. These cords also add to impact and rip resistance values depending on the breaker cord pitch (usually between 4mm and 8mm).
Therefore, higher impact resistance using a Metalcord we intensify the number of transverse cords by decreasing the pitch and number of layers of breaker cords.
Picture of Metalcord
Using your example of a 1400mm x M1000 you will see that their belt would look very different:
1400mm Metalcord M1000
Cord diameter: 2.85mm
Cord pitch: 5.3mm
Cord Design: 4x7
Number of cords @ 1400mm: 258
Impact Rating: 3393 n-Meter
1400mm Metalcord E1000
Cord diameter: 3.10mm
Cord pitch: 10.3mm
Cord Design: 7x7
Number of cords @ 1400mm: 134
Impact Rating: 2443 n-Meter
There are some great advantages to this design. One of the main advantages is the reduction in the venerable rip-prone rubber spacing between cords.
Another advantage is in the unique splice method specially designed for this belt construction that results in a strong, long lasting splice. Our splicing method is a long finger splice method where many cords are grouped into fingers instead of working with individual cords.
Also the ability to wrap smaller pullies is attractive to many system designers and those wishing to convert systems designed for fabric belting to steel. In this example minimum pulley diameters would be: Head 630mm, Tail 500mm, Snub 400mm
For increased troughing angles, Sempertrans manufacture another unique steel cable belt called Autostable. This belt is installed in many applications troughing over 45-degrees including 65-degrees and 135-degrees (enclosed triangle). But that is a different story altogether.
There are many other benefits of the Sempertrans S.F.B.T. designs to consider. I would be happy to answer any questions you might have.
Last edited by Author; 29th January 2015 at 7:51.
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