Gears Sets A and B Mechanisms
Chain Gang MkI
Chain Gang Model
This is a model to demonstrate the use of the Gears available in the A & B Gears Sets and the Mechanisms Set from the 1950's. The models from the manuals have been modified and built on individual bases to create modules. Each module can be mounted on the twin rail bed in any order. Each module is powered by the motor module through a chain drive. This model is a work in progress and I'll be adding and upgrading it as time goes on.
This is a model to demonstrate the use of the Gears available in the A & B Gears Sets and the Mechanisms Set from the 1950's. The models from the manuals have been modified and built on individual bases to create modules. Each module can be mounted on the twin rail bed in any order. Each module is powered by the motor module through a chain drive. This model is a work in progress and I'll be adding and upgrading it as time goes on.
Twin Rail Bed
The rails are flat girders that are mounted in part 52a flanged plate to set the spacing. The flat girders are butt joined and mounted in flanged plates. The flat girders and flat plates are connected in a running bond to make up any length required depending on the number of modules on hand.
Each module is able to slide on the rails to adjust the overall chain drive tension. Each module is secured to the rail by aligning the flanged plate holes and the flat girder holes and running an axle through. (easier said than done).
GEARS A.2 Reduction Gearing for E020 Motor
The motor drive module consists of a 20 VDC Cricket Ball drive motor powered from a variable voltage power supply. A worm gear is fixed to the motor shaft. The worm gear in turn drives a 60 tooth gear wheel. Also on this shaft is a 19 tooth pinion driving 57 tooth gear wheel which also has a one inch sprocket that will drive the modules.
The rails are flat girders that are mounted in part 52a flanged plate to set the spacing. The flat girders are butt joined and mounted in flanged plates. The flat girders and flat plates are connected in a running bond to make up any length required depending on the number of modules on hand.
Each module is able to slide on the rails to adjust the overall chain drive tension. Each module is secured to the rail by aligning the flanged plate holes and the flat girder holes and running an axle through. (easier said than done).
GEARS A.2 Reduction Gearing for E020 Motor
The motor drive module consists of a 20 VDC Cricket Ball drive motor powered from a variable voltage power supply. A worm gear is fixed to the motor shaft. The worm gear in turn drives a 60 tooth gear wheel. Also on this shaft is a 19 tooth pinion driving 57 tooth gear wheel which also has a one inch sprocket that will drive the modules.
GEARS A.13 Simple Epicyclic Gear Mechanism
This mechanism might be useful to drive a mill to grind grain. Mostly it's just fun to watch it spin aimlessly.
This mechanism might be useful to drive a mill to grind grain. Mostly it's just fun to watch it spin aimlessly.
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GEARS A.14 Intermittent Motion Mechanism
Power from the chain is turned 90 degrees through the bevel gears which continuously drives the main shaft. The worm gear turns the gear wheel that has 4 pins which press against the plate. The plate is on a spring loaded assembly. As the gear wheel rotates the pins push the plate away, disengaging the dog clutch at the end of the drive shaft causing the output shaft to stop turning. As the gear wheel continues to rotate, the pins move away from the plate. The spring will then push the output shaft toward the main shaft allowing the dog clutch to re-engage which transfers power to the output shaft and the fan starts turning.
Power from the chain is turned 90 degrees through the bevel gears which continuously drives the main shaft. The worm gear turns the gear wheel that has 4 pins which press against the plate. The plate is on a spring loaded assembly. As the gear wheel rotates the pins push the plate away, disengaging the dog clutch at the end of the drive shaft causing the output shaft to stop turning. As the gear wheel continues to rotate, the pins move away from the plate. The spring will then push the output shaft toward the main shaft allowing the dog clutch to re-engage which transfers power to the output shaft and the fan starts turning.
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Front View - Dog Clutch - Open
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Front View - Dog Clutch - Closed
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Rear View - Dog Clutch - Open
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Rear View - Dog Clutch - Closed
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The module pictured below has two mechanisms on it.
GEARS A.12 Twin Drive Unit (GEARS B.13)
The mechanism of the left in the picture below demonstrates that two identical gears will rotate in opposite direction depending on which side a gear is driven on. The drive shaft is powered from the drive chain through a sprocket. There are 2 pinions on the drive shaft, one meshing with a crown gear on its right side, the other pinion meshing with a crown gear on its left side. When the drive shaft is rotating the 2 driven shafts will rotate in opposite directions from each other. The pinion / crown pair translates the motion 90 degrees.
GEARS A.3 Reversing and Reduction Gear (GEARS B.4)
The mechanism on the right uses counter rotation principle from the twin drive mechanism to build a forward / reverse gearbox. The drive shaft is powered from the drive chain through a sprocket. A crown gear at the end of the drive shaft meshes with one of two pinions on the control shaft but not both at the same time. When the control shaft is to the left, the pinion on the right meshes with the crown gear and the large pinion on the output shaft turning the output shaft in the forward direction. When the control shaft is to the right the pinion on the left meshes with the opposite side of the crown gear turning the control shaft in the opposite direction. The left pinion remains engaged to the large pinion even though its position has changed. The large pinion also reduces the speed of the output shaft. The output shaft now rotates in the reverse direction.
GEARS A.12 Twin Drive Unit (GEARS B.13)
The mechanism of the left in the picture below demonstrates that two identical gears will rotate in opposite direction depending on which side a gear is driven on. The drive shaft is powered from the drive chain through a sprocket. There are 2 pinions on the drive shaft, one meshing with a crown gear on its right side, the other pinion meshing with a crown gear on its left side. When the drive shaft is rotating the 2 driven shafts will rotate in opposite directions from each other. The pinion / crown pair translates the motion 90 degrees.
GEARS A.3 Reversing and Reduction Gear (GEARS B.4)
The mechanism on the right uses counter rotation principle from the twin drive mechanism to build a forward / reverse gearbox. The drive shaft is powered from the drive chain through a sprocket. A crown gear at the end of the drive shaft meshes with one of two pinions on the control shaft but not both at the same time. When the control shaft is to the left, the pinion on the right meshes with the crown gear and the large pinion on the output shaft turning the output shaft in the forward direction. When the control shaft is to the right the pinion on the left meshes with the opposite side of the crown gear turning the control shaft in the opposite direction. The left pinion remains engaged to the large pinion even though its position has changed. The large pinion also reduces the speed of the output shaft. The output shaft now rotates in the reverse direction.
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GEARS A.11 Differential Gear (GEARS B.12)
When a vehicle drives around a curve the inside wheels turn at a different rate than the outside wheels because the inside curve is shorter than the outside curve. A differential allows both wheels to be powered even though they turn at different rates. Each wheel is connected to its own axle and crown gear and can rotate independently. In other words if one wheel stops the other can still turn. Each crown gear meshes with 2 pinions. Both pinions are mounted in a cage that is rotated by the large crown gear. The large crown gear meshes with a pinion on the drive shaft which is powered from the drive chain through the small sprocket. Although the cage is mounted to both of the wheel axles it is not fixed to either of them and can turn freely. As the cage rotates resistance in the pinion / crown mesh turns both wheels at the same rate. If the left wheel slows, the cage continues to rotate. The pinions now turn on the slowed crown gear and in turn rotate the opposite crown gear faster which turns the right wheel.
The model actually demonstrates a shortcoming of this design. The drive chain turns the large sprocket that is connected to an eccentric throw which drives an axle in a left / right motion. When at the end of travel the axle puts pressure on a wheel and stops if from turning. The other wheel continues to turn. A real life situation is when the left wheel is on ice or mud or off the road. Because the right wheel has more friction the power is directed to the left wheel causing it to spin uselessly. If both wheels are stuck then either the engine stalls or something breaks.
When a vehicle drives around a curve the inside wheels turn at a different rate than the outside wheels because the inside curve is shorter than the outside curve. A differential allows both wheels to be powered even though they turn at different rates. Each wheel is connected to its own axle and crown gear and can rotate independently. In other words if one wheel stops the other can still turn. Each crown gear meshes with 2 pinions. Both pinions are mounted in a cage that is rotated by the large crown gear. The large crown gear meshes with a pinion on the drive shaft which is powered from the drive chain through the small sprocket. Although the cage is mounted to both of the wheel axles it is not fixed to either of them and can turn freely. As the cage rotates resistance in the pinion / crown mesh turns both wheels at the same rate. If the left wheel slows, the cage continues to rotate. The pinions now turn on the slowed crown gear and in turn rotate the opposite crown gear faster which turns the right wheel.
The model actually demonstrates a shortcoming of this design. The drive chain turns the large sprocket that is connected to an eccentric throw which drives an axle in a left / right motion. When at the end of travel the axle puts pressure on a wheel and stops if from turning. The other wheel continues to turn. A real life situation is when the left wheel is on ice or mud or off the road. Because the right wheel has more friction the power is directed to the left wheel causing it to spin uselessly. If both wheels are stuck then either the engine stalls or something breaks.
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Chain Gang MkII
Chain Gang MkII
It was difficult to secure modules to the previous rail bed. The flange plates fit over the rails so most of the time the holes did not align well enough to insert an axle or screw. The rails are now mounted to the outside of the base flange plates to give space for the modules to fit inside the rails. The holes align well now and it is easy to mix and match the modules.
When its sitting on a a table, the table will act as a sounding board and amplify the noise. There are 4 foam pads under the rail that reduce noise.
The chain tensioning module at the end opposite the motor has a course adjustment to take up slack caused by swapping modules and a fine adjustment for setting the chain tension. I also added idler sprockets to direct the chain over more teeth of the module drive sprockets.
Some of you will notice that the motor is an A49 made by A.C. Gilbert. I do not apologize for using it because it is a well made motor, it looks cool and outperforms most if not all Meccano motors. The gearbox is another matter.
It was difficult to secure modules to the previous rail bed. The flange plates fit over the rails so most of the time the holes did not align well enough to insert an axle or screw. The rails are now mounted to the outside of the base flange plates to give space for the modules to fit inside the rails. The holes align well now and it is easy to mix and match the modules.
When its sitting on a a table, the table will act as a sounding board and amplify the noise. There are 4 foam pads under the rail that reduce noise.
The chain tensioning module at the end opposite the motor has a course adjustment to take up slack caused by swapping modules and a fine adjustment for setting the chain tension. I also added idler sprockets to direct the chain over more teeth of the module drive sprockets.
Some of you will notice that the motor is an A49 made by A.C. Gilbert. I do not apologize for using it because it is a well made motor, it looks cool and outperforms most if not all Meccano motors. The gearbox is another matter.
Closer look at the A49 motor. You can also see how the mechanism module fit inside the rails but the A49 module does not. The A49 is too wide to fit inside the rails.
Rear view showing A49 mounting. The module does not move side to side because the chain side rail is trapped between the motor mounting screw and nut and angle bracket.The axles secures the module to the rail bed.
Course adjustment of the chain tensioner module is made by moving it to an appropriate location on the rail. Fine adjustment is made by moving the upper sprocket carriage.
New car differential.
In June 2015 the BCMM had a booth at the Vancouver Mini Maker Faire where I displayed my Chain Gang. I met several young people who had no trouble understanding the mechanics of the Chain Gang as well as others who were fascinated by the rotating fans.
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