B.C Meccano Modellers
Here are a few ideas dealing with the operation of cranes. The Mini Crawler Crane was built with improvements from my first version shown at the bottom of this page. The Crawler Crane has 4 operational functions: Hook, Boom, Slew and Travel.
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Mini Crawler Crane
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A general overall view of the crane. Nothing fancy here as we get more into the details of the mechanics of the model. Various boom designs can be utilized. Add another drive to convert model to a Drag-Line.
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A closer look at the tracks and body of the unit.
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The model is based on a 1-1/2" x 1" x 5-1/2" Flanged Channel The object was to see how to fit the necessary mechanisms into such a small area. There are 4 spring loaded shafts with an end collar. These are pushed inwards to mesh with the gearing on the opposite side of the body. Further details below.
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Here we have the bearing that is made up from 2 Wheel Flanges. Bolted to the upper flanged piece is a 1-1/2" pulley to keep the spacers (rollers) in place. The lower flanged piece has a 2-1/2" Gear Wheel attached which is driven by a 19 tooth pinion that is pushed downwards from above to engage the drive.
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This is the shaft that engages the slewing movement. When pressed down the contrate engages with a 19 tooth pinion driven from the drive train. The bottom end of this shaft has a 19 tooth pinion to mesh with the 2-1/2" bearing gear. When released the body is free wheeling and can be turned by hand.
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This horizontal shaft operates the track movement by sliding a 25 tooth pinion into a 50 tooth contrate. The end of this shaft has a 19 tooth pinion driven by the drive train. The vertical shaft runs through the bearing into the drive shaft attached to the tracks.
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Here you can see the two winding drums with push rods, springs, drums and braking arrangements. The top rod (left) is the hoist drum. When the rod is pushed in. it engages a 19 tooth pinion into the drive train causing the drum to turn. The drum consists of two 1/2" pulleys secured to the shaft (boss to boss). One side has a 1/2" rubber tire over it so that when the shaft is released, rubs up against two bolt ends to produce enough friction to hold the cable. One bolt can be seen to the upper left of the shaft. The other directly below. The same arrangement is on the rear shaft but has 1" pulley and tire. This is the boom drum. Drag bolts are on either side and the above the shaft.
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I have lightened up the photo to help show a little more detail of the winding drums as seen from the back side. |
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OK. So now that we know how the drive mechanisms work lets have a look at the powered drive train. The motor is the common 3 to 6 vdc unit that is included with most to the newer French sets. It will drive this crane with the 6 volt switched battery pack but if you want to run it for any length of time I would advise the use of a Regulated Power Supply. I am surprise by the power to drive everything when geared properly. The crawler is a bit slow as geared but cranes move slowly.
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This is an overall view of the drive train. The center 57 tooth gear wheel drives any or all of the three 19 tooth pinion, depending on how many fingers you have. The gear on the right drives the tracks. |
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The tracks are from the Meccano Army Multikit. 4 x 10 tooth sprockets are in use as well as 6 idlers from newer sets. The rear sprocket keeps the track in line, the second is centrally located as seen by the protruding axle.
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Overall underside view of the track carriage showing the right angle drive feeding the drive axle.
At this time the unit only travels forwards and backwards but I am working on an all pinion differential that will complete the model. |
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Dock Side Crane
This was my first version of a small dock side crane and is basically a mini version of the mechanisms of the no 10.7 Block Setting Crane.
I built the 10.7 model from the French Set that came out in 2000 in Dark Red and Green. Oddly enough there was no provision for braking the hook cable.
This setup has 3 functions; Hook, Boom and Slew so it can also be used for Yard and Tower Cranes where no ground travel is required.
I built the 10.7 model from the French Set that came out in 2000 in Dark Red and Green. Oddly enough there was no provision for braking the hook cable.
This setup has 3 functions; Hook, Boom and Slew so it can also be used for Yard and Tower Cranes where no ground travel is required.
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In this version both of the drum shafts are pushed in by levers.
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A Rubber Band is used to provide ample breaking. The center rubber pulley if fixed tight to a bolt to provide friction for the band. The other 2 rubber pulleys rotate with the drum shafts when engaged
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