FRICTION CRANES SHOES

Just in! Cranes that have internal expanding friction clutches and Lattice Booms were commonly referred to as “Friction cranes” by the Standard writers and the Manufacture themselves. Nowadays, the Clutch type drums on the new lattice boom cranes are being replaced with Hydraulic Winches. So, these crane types are currently being named “Conventional cranes” (I wonder what an un-conventional crane is).

A hydraulic winch on lattice boom crane is nothing new; I worked on one in 1962 at Cape Canaveral, a 100 ton Bucyrus Erie with a hydraulic winch and a Triangular boom. But, with the demands of modern cranes the hydraulic winch has advantages, one thing, less moving parts subject to fatigue.

The photos following show a broken friction shoe on the main hoist of a Link Belt crane. This is the “power down side”, and if you think about it is actually being “pulled” when working due to its job of slowly lowering a weight against gravity.

When it failed the load was still controlled because the other side was engaged but, the operator recognized something went wrong by the vibration he felt in the crane. He set the load on the ground and went back to look and this is what he found!

Inspection of the Frictions clutches is as follows;

1. Lining thickness
2. Contamination from oil or water
3. Evenness of drum surface and contamination
4. Proper adjustment
5. Observe operation for smooth engagement
6. Visible damage or cracking of shoes
7. All pins, springs and keepers in place
8. Evidence of overheating of any component
9. Other noticed problem observed during operating under functional load test

Well this one got away, but now I look closer at this area of the shoe for “hammering” and cracking, so should you?

FOUR CRANE LIFT AT BATH IRON WORKS SHIPYARD

A 1000 Ton Deck House for the Destroyer DDG-1000 was lifted in place at Bath Iron Works Ship Yard in Maine this Dec. 2012. This was the first four crane pick at the yard. All four cranes were inspected, tested and certified to OSHA's maritime regulations done by National Crane Services. Also the US Navy certified these cranes per their regulations.

National Cranes Services has tested and certified the cranes at Bath Iron Works since the 1980’s. Two of the cranes used were portal cranes, which are permanently located at Bath Iron Works.  One of them is an American 300/25 ton capacity portal and the other portal is a Chinese 300/125/25 ton capacity and positioned on opposing runways.  These shipyard cranes are continually serviced, inspected and tested in accordance with Maintenance Program established by Bath Iron Works many years ago.  Greg Bridgman, Maintenance Engineering Manager, who is responsible for all of the crane documentation. These cranes operating capabilities’ were familiar to Bath Iron Works. 

However, the crawler cranes, two 16000 Manitowoc crane which are owned by Reed & Reed of Woolwich, ME, were not familiar to Bath Iron Works and needed to be evaluated by Bath Iron Works, US Navy and National Crane Services during the entire lift planning and set-up process. The cranes were set up and rigged with their “Max-er” lift attachments, which were a 157’ heavy boom, wheel counterweight @ 50’ and a 97’ fixed lattice mast that gave the cranes a 609,000 LB capacity at a 50’ radius. The calculated load for each crane was approximately 460,000 LB.  

There was over a month of preparation by all parties involved before the configuration; condition and testing of the cranes were agreed upon. The owner of the cranes decided to hire two Manitowoc technicians to aid in setting up the new Max-er heavy lift attachments.  

The completed Deck House, which was manufactured from a new type material, was built in Mississippi at Ingles Ship yard then transported by barge to Bath Iron Works in Bath Maine. The barge was placed in the dry dock. The dry dock was then moored to the dock of Bath Iron Works. Then the barge and Deck House was then driven off the dry dock and into position.. The Deck House was centered between the four cranes. The cranes were facing each other, two on each side of the ship way. The Deck House was then raised approximately 80’ in one piece to be set on a new class of Cruiser being built at Bath Iron Works for the US Navy. The lift went off without a hitch on Dec. 12-14, 2012.

To watch a time lapse video of the Deck House move click the link below.

Deck House Move