Almost all steel wire ropes have a rope fitting. What types of wire rope fittings exist? And what should you pay attention to in your search for the right fitting? Discover more in this article.
A wire rope fitting is often combined with a hook, turnbuckle or shackle. The fitting that best suits the steel wire rope depends on the application. First, we make a distinction between permanent and non-permanent wire rope fittings.
Permanent wire rope fittings
A permanent wire rope fitting is inseparable from the steel wire rope.
Examples of permanent wire rope fittings are:
- Sockets (molded or pressed)
A properly molded socket is the strongest wire rope fitting and is 100% efficient. A molded socket is therefore widely used in situations where you want to realize the maximum breaking load of the steel wire rope. For example, this application is frequently used for breaking tests. We also often see the application of sockets at bridges and locks.
A pressed socket (also called terminal) is suitable for steel wire ropes with a diameter of up to 65 mm. In comparison with molded sockets, pressed sockets save a lot of weight. This is especially important for guy-wires. Think of mobile cranes and draglines.
The talurit clamp is often used to make a loop connection (with or without thimbles). When applied correctly, 90% of the minimum breaking load is retained.
A thimble is found on the inside of the loop or the eye at the end of a wire rope. The (reinforced) thimble ensures that the steel wire rope does not kink under load. The thimble also prevents wear and keeps the eye of the wire rope open (make sure the thimble has the correct pin diameter).
Non-permanent wire rope fittings
Non-permanent wire rope fittings are connections you can loosen without damaging the steel wire rope. This makes them suitable for situations where you cannot determine the correct cable length. This is the case, for example, with spans.
Non-permanent wire rope fittings are also often preferred if the wire rope has to be disconnected regularly. This is the case with mobile cranes, for example.
Some of the many non-permanent rope fittings:
- Wedge socket or wig sockets
A wedge or wig socket is an end fastener that is suitable for situations where the fastener needs to be disconnected regularly. This is the case, for example, with blocks of mobile cranes or if you need to adjust the rope length in between.
Nowadays, mobile crane fittings are pressed or molded onto the cable, which is then fixed in a wedge or wig socket.
- Wire clamp or U-bolt
A wire clamp is used to provide both cable ends with a loop by clamping them against each other. This wire rope fitting is widely used for moving load horizontally. A wire clamp or U-bolt is unsuitable for lifting purposes.
- Eureka grip
Eureka grips are only suitable for standard 6- or 8-strand steel wire ropes. They are not suited for compacted and hammered steel wire ropes. The advantage of a Eureka grip is that it’s quick and easy to apply.
Loss factor: influence on the workload
In most cases, the wire rope fitting affects the maximum breaking load of the steel wire rope. Each wire rope fitting has a so-called loss factor. At 90% efficiency, this means the maximum workload should be reduced by 10% because of the fitting.
Q&A webinar #5: end terminations and cutting ropes
That depends on the procedure, regulation and diameter of the rope and then its calculated depending number of strands, design of the socket and the resin used. As a general rule for standard taper sockets, apply the seizing one (1) socket basket length from the end of rope minus one (1) rope diameter. The length of the seizing must be at least two rope diameters long. For correct procedure that apply in your case please consult us as it may differ depending on socket, standard, regulations and resin used.
This is one of the different kinds of gromet making, in general, you use one rope and you put it into an endless loop. And then, 6 times the rope woven around its core. Not easy to explain but it can be explained during the next seminar. Some ropemakers have specific machines for it. Sometimes you also have cablelaid slings and this is also rope made out of ropes not out of strands and then they put some end terminations on it and “eyes” to be swaged or thimbles to be swaged and then they gonna handle it but this is a different topic and I need to prepare some slides for it to explain it properly.
Not for the sockets. Just for mixing up your resin, the resin is made out of fluid and some powder. And these ingredients have an expiration date (normally 1,5-2y). You also have to make sure that the mix is made in minimum 13 degrees celsius. Otherwise, the hardening procedure will take longer – then you can add a different powder to fasten the hardening process.
Yes, depending on the type of clips. You can use our website to see how many clips you need. . You can also look them up in the catalog. But once again use it only for emergencies and don’t use it for permanent hoisting ropes.
Normally if you buy the clips on certex or mennens you gonna get an application form and there you can read the torque you gonna need to put on the clips will be written into a table or also on your user guide which is normally delivered with the clips. And after a while, you do the exercise again, because the rope will diminish in diameter and then you need to do the fitting with the wrench again. This is also why people in Belgium can’t use it anymore for hoisting applications because it was some bad accidents and then the third-party inspectors forbid to use this type of clips. So use other types of end terminations on overhead cranes or on other applications.
Yes it may be allowed in some markets but our learning is that avoid u-bolt clips in lifting applications.
It is prescribed that it should be 80% but from our experience, you will never have 80%. 80% is the maximum even with non-rotating ropes. And if somebody is telling you that its more than 80% they are going to need to prove it. As we talked about in the webinar these terminations are very risky to use and you really need to make sure that it is 100% correctly installed including the correct amount of torque plus dubbelchecking and re-tightening of the bolts once the rope has been loaded. Also rope construction is a factor that effects the efficiency. We have made several tests over the years also with correct installation and our experience tells that 80% is difficult to achive and for safety reasons we recommend to only expect 60-70%
You can find the table for aluminum ferrules from Talurit here. Click the document tab and choose download.
Design and architecture projects and are not to be used for lifting purposes. I dont know the efficiency of these terminals and they may differ between manufacturers and also which rope construction it is design for. Best tip is to contact the manufacturer. You can find an interesting document on the topic here.
If you mean mobile cranes then it is a lot easier. 15 or 10 years ago we used end fitting easily for reeving up to multiple reeving systems into blocks, the problem was that it was an end stop that was fitted on the rope and if the rope got damaged you have to replace the whole rope. But now we have this easy socketing on end stops so you can cut your rope where it’s damaged and then just by pouring the end stop on it, then you can use your rope again. The fitting has to be adjusted for the right socket but you don’t need to buy a whole new rope. You have to be certain that the end stop is the right one for your socket that’s on your crane – that’s it for non-rotating ropes. In some applications, these fittings can also be used for 6 or 8 strands ropes. And then normally the fitting will be so constructed that you can’t turn the fitting into the socket. Then the socket and the end fitting are blocked together so that the rope cannot rotate into the socket.
What we have seen is for nuclear plants because they don’t know what the effect would be on resin after 20 or 30 years due to radiation that will get into the resin. So therefore it’s not used in nuclear power plants. The standard here is to use liquid metal instead – I think that’s the only application I know where they don’t use it. Otherwise, these liquid metal to pour in has the advantage for emptying the socket again you just apply the right temperature. For resin you have to press it out and you need the equipment to be able to do that. The temperature will however deteriorate your wires and also your socket. Therefore when you heat it up so you need to be careful so you don’t damage your material.