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| Crawler Crane Body | ||
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The body, or main frame, of the crawler crane is made of two parallel beams that cantilever out from the turntable. The boom and superlift are attached to the body just above the turntable.
The turntable is made from a large Technic turntable with a built-up base around it. The base slides on 2x2 smooth plates (tiles). There is an 8-inch long 3/16-inch threaded steel rod that runs through the turntable for extra support. |
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The 3 winches are sandwiched between the parallel beams of the frame. The main hoist line, boom holdback line, and superlift holdback line are each connected to a motorized winch. Details of the gearing are given below.
There are two other motorized winches, one for the jib line and one for the jib holdback line. These winches are built into the main boom structure, just above the hinges at the front of the crane body. |
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The main parallel beams are 8 bricks in height and are constructed mostly of Technic beams. Plates are attached to the sides of the beams (look closely and you will see studs on the sides of the frame) by means of 1L gray pegs (the ones that leave a stud sticking out when inserted in a hole). The plates add extra strength and rigidity. | |
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The counterweight on the back of the body (the large blue boxes) are filled with .177 caliber BB's (for air rifles). I had a big sack of them in storage and decided they are better used as weights for my crane. The are excellent when used as ballast because they conform to the shape of the container. | |
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This shows the inner workings of the body. The 9 volt motors, gear trains, and spools are all crammed in between the two parallel beams of the body. The distance inside-to-inside of the body is 10-wide, or 10 brick widths.
The gear ratio for both the main line and boom holdback line is 1:360. The high gear ratio was necessary to gear down the 9V motors. All 9V motors used are the non-geared type, part 2838c01. The image was created with MLCAD. See www.ldraw.org for info on the program.
LDRAW file (DAT) of this model:
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The spools of the main winches could be disconnected so that they could spin freely. This helped greatly when I needed to quickly let the line out.
The image to the left shows the disconnected position. The set of 24 toothed gears could be pushed in allowing the main spool to rotate freely. The spools were made of two 40 toothed gears with 4 additional axles inserted between (see pic). This created a large diameter (larger diameter than just one axle through the center) drum on which to spool the line. |
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Here the spool is connected to the gear train. The 24 toothed gears slide out to make the connection. | |
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This shows only the forward most winch (for the main hoist line). The spool has been moved up for clarity. | |
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This shows only the middle winch (for the boom holdback line). The spool has been moved up for clarity. | |
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This shows only the rear winch (for the superlift holdback line). The spool has been moved up for clarity. | |
| » Crawler Crane | » General | |||
| » Lifting | ||||
| » Body | ||||
| » Crawler | ||||
| » Booms | ||||
| » Counterweight | ||||
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Copyright © 2001 - 2002, Thomas Avery email me! |
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