This integral part of the power to gearbox is essential in Strain Wave Gears Factory stabilizing the gearbox and driving the locomotive. This unit is critical depending on the type of locomotive you are going to modify.
Small engines usually have some space problems and the can motor drive shaft to the gearbox drive shaft is almost non-existent. To solve this dilemma you have a choice of two means of fastening the two drive shafts together and still maintain stability of the gearbox. One is the old method of using neoprene tubing to act as a drive mechanism and to stabilize the gearbox. The other is a U-Joint and couplings however, this method requires a means to stabilize the gearbox.
The newer tubing available today is far more stable and holds its elasticity far longer than the original tubing. Previously the tubing lost all elasticity and became brittle. On the other hand the U-Joint and couplings works similar to the drive shaft on an automobile. The draw back is that when the shaft turns there is a monetary break in the stabilizing properties of this type of mechanism. The coupling can slip out of its hold due to the torque and the desire of the gearbox to ride up or spin on the main gear.
To compensate for this anomaly one must find a means to hold the shaft connection steady. One way is to build a bracket with a bearing to be attached to the frame of the locomotive. The shaft of the can motor is then inserted into the bearing and the bracket is attached to the frame. Once this is done, the U-Joint and coupling are placed on the can motor shaft and the two interfaces, can motor shaft and gearbox shaft, are coupled together.
With this method you must have a means to adjust the couplings so the do not bind. This is usually done by having drilling an oblong hole at the attach point for the can motor. This allows the user to move the can motor backwards or forwards before tightening the fastener down. However, many times the space between the two shafts is so small the neoprene tubing method is the only means that will work.
The other type of stabilizer is the torque arm. This one is my favorite however, it is complicated. You have to build the torque arm from scratch. The trickiest part of this operation is the drilling and taping of two holes in the gearbox casement. You must be very careful not to penetrate the void in the gearbox casement.
The other part is making the torque arm its self. This is a relatively long piece of brass sheeting at about a quarter inch wide. You would cut it to meet the length of the locomotive you are working on. One end is bent up 90 degrees. This end would have two holes drilled to match the two holes on the gearbox encasement.
At the point where the can motor would be stationed you would build a bracket with a right angle tab. The bracket would be drilled out to match the can motor configuration and the two screw holes in the can motor. The bracket would then be soldered to the torque arm. The end of the torque arm would be equal in length from the gearbox encasement to the end of the can motor.
On the bottom of the torques arm just beneath were the can motor sits you would solder a sold brass shaft of 2mm in diameter and about ? inch in length. Also, you would solder in place a small half spring at the same soldering point. Then you would drill an oblong hole in the frame where the original motor attach point was located. This hole will allow the 2mm shaft to ride up and down much like the real torque arm does. The motor is heave enough to stop the gearbox from trying to spin.
This is, in my opinion, the best stabilizer of them all and keeps the drive mechanism in perfect alignment.
geardrives