wire rope

What do the insurance engineer/surveyor's periodic test reports say?

What does the original equipment manufacturer's maintenance manual say?

In other lifting equipments the number called "to km" which is the product of lifted loads by the stroke length used at each lifting is used as criterion for fatigue and wear.

If the wire rope strands are not opened up (small wires have not got cut and opened the strands) then wire rope can be used. It will be better to examine the wire rope for full legth. Also it should be regularly lubricated for longer life.

Suresh Sharma.

In the U.S. (where are you located?) there are very specific crane wire rope inspection procedures and frequencies. If memory serves me right OSHA lays them out. Proper inspection of these is very important because it is accepted that these loads may go "overhead".

One of the attributes that often determines the wire ropes life is: % of diameter reduction of the outer strands due to wear.

If the government where you are located has good guidelines on wire rope inspection when involved in crane or overhead lifting please implement then. If those standards do not exist in your location, for safeties sake please follow the standards of a regulating body from one of the industrialized Nations.

The crane OEM should be able to provide a recommendation for maximum service life. The US Federal OSHA standard for cranes and derricks requires changing wire rope based on conditions, not time. Here is the criteria it mandates.

1926.550(a)(7) Wire rope shall be taken out of service when any of the following conditions exist

1926.550(a)(7)(i) In running ropes, six randomly distributed broken wires in one lay or three broken wires in one strand in one lay;

1926.550(a)(7)(ii) Wear of one-third the original diameter of outside individual wires. Kinking, crushing, bird caging, or any other damage resulting in distortion of the rope structure;

1926.550(a)(7)(iii) Evidence of any heat damage from any cause;

1926.550(a)(7)(iv) Reductions from nominal diameter of more than one-sixty-fourth inch for diameters up to and including five-sixteenths inch, one-thirty-second inch for diameters three-eighths inch to and including one-half inch, three-sixty-fourths inch for diameters nine-sixteenths inch to and including three-fourths inch, one-sixteenth inch for diameters seven-eighths inch to 1 1/8 inches inclusive, three-thirty-seconds inch for diameters 1 1/4 to 1 1/2 inches inclusive;

1926.550(a)(7)(v) In standing ropes, more than two broken wires in one lay in sections beyond end connections or more than one broken wire at an end connection.

1926.550(a)(7)(vi) Wire rope safety factors shall be in accordance with American National Standards Institute B 30.5-1968 or SAE J959-1966.

I'm not sure that lubricating wire rope is always a good idea. Certainly on the face of it it seems a good idea as far as the condition of the wire rope is concerned, but I am concerned at the stop grab. Apparently when operating a crane it is wise to run it with a dummy load in the morning to burn off the condensed dew so the brake will work at time of application. I know for my motorcycle I screwed up using a lubricant in the throttle slide, which was intended to stay dry.

My experience with the machine wire rope was while scrapping a ship, or rebuilding an ocean pier. It was the most dangerous job I ever did, and I much enjoyed it, but it didn't pay enough for me to keep at it.

I will say as a fact that when working with wire rope you had better have some gloves and your tetanus shot up to date.

I am interested in hearing of some wire rope lubricant, since I never saw any used on the 20 ton crane I worked with.

As said, it was a very dangerous job, and I can also say never go below decks on a dead ship, without a flashlight. There is no dark like the bottom of a dead ship.

I worked for years on container and gantry cranes at a port in SC and we greased all wire rope used on them; main hoist, boom, and trolley. We also did hoist wires on our mobile cranes.