Quote:
Originally Posted by MrB
Cool, do they have any sort of DRO's(digital read-outs) up there?
I mean for things like cable length, degrees of rotation, distance of cable from main column, etc, etc?
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On the new late (very late) model ones yes, but nothing at all on the old units. Like the old Favco's.
The old ones have an angle indicator on the boom. This is just a pointer with a weight on the bottom pointing to degrees on a semicircle plate.
The tower crane driver will always put the man-box in exactly the same place on the ground.
When he first picks it up he'll note the deck rotation angle & also the boom luffing angle to get the position. (both indicators similar to described above) When the box is on the hook (with the box still on the ground) the driver will turn around & look at the cable drum on the winch & count how many layers of cable have run off.
So when he's putting the box on the ground, he'll slew & luff until his 2 indicators are pointing to the correct angles & then while he's lowering the the box to the ground he'll turn around & look out the back window & watch the cable drum.
Many of the experienced drivers will still do it this way even in a new crane, because they don't trust the digital readouts......
This pic is a "Favco". easiest way to tell a Favco is the 2 hydraulic rams at the base of the boom. These are the luffing rams which push the boom up & down. Other types of cranes use a wire rope & pulley system to lift & lower the boom.
Also a Favco has the ops cabin right in the middle between the 2 rams under the boom butt. Look at the cranes in the original pic. They have no rams & the ops cabin is out to one side, not in the middle.
