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Dave Ware's Gilbert Erector Inertia Machine

Dave writes: "Here is a handy drive that allows a model with a lot of inertia to freewheel after the power is removed from the motor. It could also be used to pulse a motor for part of each rotation of a model to give the allusion of a one cylinder steam drive on a walking beam engine or power plant. This would require the use of a commutator (such as was used on the Ferris Wheel Illumination Kit) to power the motor during a fixed part of the rotation cycle. This set up would lend itself to driving a model more directly, i.e. without a string around the flywheel in the case of the Giant Power Plant.

This is how it works: The gear is the only thing that is locked to the shaft. It can turn freely in a counterclockwise direction while the rest on the mechanism stands still. When the pulley and pawls are driven counterclockwise, one or more of the pawls locks onto the teeth of the gear and the shaft is driven. It only works with the shaft positioned horizontally.

Alternately the shaft could be powered. The rest of the mechanism would then freewheel in a clockwise direction and be driven by the shaft. However, high speed operation may centripetally spread the pawls and limit locking.

It is made with 8 O pawls, 4 CH right angles, 3 BN turret plates, 1 BT pierced disk, 1 CJ 36 tooth gear, 2 P37 collars and 14 washers. The BT and one P37 do not need a set screw.

The four pawls are each made with a CH and an O. They pivot freely. Each pivot screw (1/2") starts with a washer, goes through the round hole in the CH (not the elongated hole), then another washer then through the hole in the BN, another washer and finally two nuts locked together. Each pawl is limited in travel by an O mounted on the BN. These are adjusted in the slotted BN holes so that the pawls can clear the gear teeth, but do not pivot past the stops. A standard pulley made from 2 BNs and a BT is sandwiched behind the mechanism with the BT side out. The pivot screws are long enough to pass through holes in the pulley. Nuts are not used. The shaft has the CJ locked to it, passes through a P37 and washer, then the sandwich and finally another washer and another P37. This last P37 is locked to the shaft and holds everything together. Lubricate around all the washers for a very smooth operation."