An asymmetric wedge socket is a simple and efficient method of terminating a wire rope, which is used on many lifting machines. However, if fitted wrongly it can lead to problems. Unfortunately some examiners have a tendency to reject correctly fitted sockets for the wrong reasons.
First and foremost the live portion of the rope must always be positioned to align with the back of the socket so that the load is in a straight line along the longitudinal axis of the socket. The rope passes around the wedge and the tail should project out of the base of the socket. The end of the rope should be served with soft wire to prevent it splaying.
The length of tail required depends upon the way the tail is to be finished and there are two options. One is to form it into a small loop secured with a single rope grip. The other is to clamp it to a separate short piece of rope, again with a rope grip. This latter method has the advantage of taking a little less space. The disadvantage is that it requires a separate piece of rope, the ends of which should also be served.
In both cases, the U bolt of the rope grip should be on the part of the tail nearest the socket and the distance from the rope grip to the nearest part of the socket body should be about 75% of the length of the wedge. This length is long enough to avoid deformation of the rope, yet still prevents the wedge from exiting the socket body if the rope becomes slack.
If the looped method is used, it is customary to secure the loop to the live portion of the rope with soft wire. This is simply to make the termination neater and is not load bearing. One all too common error is to secure the tail to the live portion with the rope grip. This should never be done, as it alters the geometry of the termination and places an undue local stress on the rope.
Another common misunderstanding arises because some makes of wedge socket have a small hole drilled through both the wedge and socket body. A piece of wire or perhaps a split pin is used to keep the two components together until the rope is fitted. That is the sole purpose of the hole. It is not intended to line up after the rope is fitted, nor is it intended as a means of securing the wedge.
Exam deadlines
One of our member companies does the thorough examination of a large quantity of lifting accessories and portable lifting machines for a customer. Its customer uses this equipment on sites all over the country and arranges for it to be returned to a central location for examination every six months. For whatever reason, the customer tries to keep all the equipment on the same periodic cycle. Any new equipment purchased between times gets examined at the end of the current cycle to bring it into the same routine. The consequence is that every six months all the equipment is due for examination on the same day.
Not only is it obviously impractical to examine all this equipment in the space of a single day, this approach
also means that, when equipment is returned from the various sites, there is nothing still within a current examination period to replace it with. In practice what seems to happen is that some equipment is examined ahead of the due date, whilst other equipment stays in service beyond the due date until it can be replaced and returned.
The member company was clearly under pressure to sanction the continued use of equipment overdue for examination. I explained that the duty to have the equipment examined by the due date rested squarely with its customer and, if its customer continued to use the equipment, it would be in breach of Regulation 9 of LOLER. The fact of the matter is that LOLER makes no exceptions for the use of equipment overdue for examination; even if it were willing to do so, the member company would simply not have the authority to sanction it.
