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Bruce Hansen's No. 10 Erector Traveling Crane Coaler

Bruce writes: "For those of you not familiar with the Erector ED triple-drum hoist of 1927, it was a 'one-year only' part included in the No. 8 and No. 10 sets. As the name implies, there were three drums, and the majority of illustrated models used them in a hoist or crane configuration. The lower drum came fitted with a BF ratchet and P49 gear so the drum could be turned in one direction, but not the other unless the BF ratchet was manually released. I can see this drum as a natural for raising and lowering the boom of a crane model. The model builder would turn the crank winding up string on the drum to raise the boom, but had to release the BF ratchet to release the woundup drum to lower the boom. The upper two drums are tied together through a central P13 pinion gear mounted on a crank. The drums each have CJ 36-tooth gears on their axles, so turning the crank rotates both drums in the same direction at the same rate. The upper drum can be turned individually by sliding the crank inboard to mesh with a second CJ on the upper drum axle and fall out of mesh with the middle drum axle. So what keeps the middle drum from spinning once the crank gear comes out of mesh? The middle drum has an integral pulley with a friction wire limiting its rotation.

Some No. 10 models with ED hoist and BM clamshell buckets.

Another cool part from 1927 (through 1932) was the BM clam shell bucket. Naturally, a loop of string to a drum or axle can be used to raise and lower the bucket. The bucket has a central weight which opens the bucket when the weight is allowed to drop. Lifting the weight pulls on linkages which in turn closes the bucket. The catch is the two strings used to raise/lower the bucket and open/close the bucket have to be wound simultaneously to raise/lower the bucket and keep the open/close state of the bucket the same. I know, a bit confusing. Imagine the bucket setting still, then pull up on the weight which closes the bucket. Now pull up on the bucket string alone. That lifts the bucket, but the string to the weight stays in the same place so the weight is actually dropping relative to the lift string which in turn opens the bucket. Perfect application for the ED hoist and the upper two drums. One position of the crank moves both drums simultaneously; the other position moves just the upper drum which can be used to take up and/or let out string to the bucket weight to open/close the clam shell.

This model is the stiff-leg Traveling Crane Coaler model from the 1927 No. 10 manual. It features the ED hoist and BM clam shell bucket. Gilbert No. 10 model plans leave a little to be desired regarding step by step instructions. Conventional wisdom is models were lightly illustrated to bring out the creativity of the builder. Yeah right, probably the same line used by a few guys in New York trying to sell a certain bridge in Brooklyn... The practice of one or two drawings of a complex model allowed more models to be illustrated in the same sized manual. At least that’s my theory. Actually, the build went pretty quickly.

The design is a trolley that runs along two rails with the Clam Shell bucket hanging from the trolley. The ED is used to move the trolley along the rails and work the bucket. As drawn in the manual, the rails appear to be a pair of straight runs of C girders. Well, I built the model that way for starters and it didn’t work very well. The two rails need to run parallel to each other for the trolley to move back and forth without falling off the rails. Two straight runs of C girders 20” long are pretty flimsy. So, DP angle girders were used to stiff en the rails and give the trolley a solid track to run on. I also took some creative liberties and added P7 pulleys on the outside of the Z flanged wheels to better capture the rails.

No. 10 Traveling Crane Coaler with No. 10 dual-rear axle White truck model.

The model drawing shows the string for the trolley and bucket running from the ED hoist to pulleys at the end of the coaler, then back to the ED. My presumption is the string was meant to be tied to the hoist in a 'push me – pull me' fashion. So, depending on the direction of travel, one string was always pulling the trolley and/or bucket along. The trolley has to be strung this way, but the bucket could be tied off at the end of the coaler and work also. Something about the weight of the BM clam shell and gravity keeping the string taut. However, I stuck to the intent of the original model designers who did a nice job as the action of the trolley and bucket work rather nicely.

OK, time to play. The bucket is opened by positioning the upper crank so only the upper drum turns. String is let out so the bucket weight drops opening the bucket. Then the crank is slid so both drums are engaged and the bucket is lowered into the load below. Once into the load, the crank is positioned so just the upper drum is turned by the crank. Winding up string raises the weight which closes the bucket capturing the load. Once closed, the crank is positioned so both drums rotate; taking up string raises the bucket while keeping it closed. The front drum is used to move the trolley back and forth to position it over the dump target, in this case a dual-rear axle White truck model. At this point the load is dumped by positioning the upper crank to turn just the upper drum to let out string and open the bucket. Took some finessing, but the model works quite well!