## Saturday, April 8, 2023

20 Mechanical Principles Combined in a Useless Lego Machine

ASMR videos don’t really do anything for me, but I could watch videos of gears and mechanisms doing their thing all day long. I watched this video of 20 mechanical Lego widgets being combined into one useless machine, absolutely rapt. Bevel gears, rack and pinion, camshaft, worm gear, universal joint, Schmidt coupling — this thing has it all.

A Lego Technic model (MOC) that demonstrates 20 different mechanical principles. You may call it a do-nothing machine or a useless machine, as all it does is rotate those beautiful mechanical principles. At the end of the chain is a slowly turning minifig statue. Available in two versions: Power Functions and Circuit Cubes.

List of 20 mechanical principles

1. Schmidt coupling transmits rotary motion between two radially displaced shafts. Used, for example, in printing industries to accommodate rollers whose distance changes often.

2. Constant-velocity joint (CV joint) transmits rotary motion through variable angles while keeping a constant speed. Used in cars between wheels and the drive shaft.

3. Universal joint transmits rotary motion through variable angles. Unlike the CV joint, this mechanism doesn’t keep a constant speed. The problem is partially overcome by connecting two U-joints 90 degrees out of phase, also known as a Double Cardan shaft. Universal joints are used in the long driveshafts of trucks.

4. Bevel gears transmit rotary motion at right angles. Used in car differentials.

5. Slider-crank linkage converts rotary motion to linear motion or vice versa. Used in automobile petrol engines between the piston and the crankshaft.

6. Sun and planet gear convert rotary motion to linear motion or vice versa. Similar to a crank but requires two revolutions from the driver gear to complete one full beam stroke. It was used in steam engines in the Industrial Revolution because the crank was patented.

7. Scotch Yoke converts rotary motion to linear motion or vice versa. Used in valve actuators that require a lot of torque.

8. Chebyshev Lambda Linkage converts rotational motion to approximate straight-line motion. Used in walking robots.

9. Chain drive transmits mechanical power from one place to another. Used in bicycles between pedals and the drive wheel.

10. Belt drive transmits mechanical power from one place to another using flexible material. Used in automotive engines to transmit power to an alternator, water pump, and other parts.

11. Constant-mesh gearbox is a type of manual transmission where a gear stick is used to select gears. A dog clutch slides on the main shaft and meshes with desired gears. Used in modern cars.

12. Oscillating direction changer is a device that periodically changes the direction of rotation of the output shaft. Usage not known.

13. Torque limiter is a device that protects equipment from mechanical overload. The Lego part (60c01) uses an oval-shaped center that slides against bending metal plates. Torque limiters are used, for example, in fishing reels.

14. Winch is a mechanical device to pull in or let out rope. Used in sailboats.

15. Rack and pinion convert rotary motion to linear motion or vice versa. It consists of one circular gear (pinion) and one linear gear (gear rack). Used in automobiles between the steering wheel and front wheels.

16. Offset gear is a spur gear where the shaft is mounted offset from the center of the gear. In this Lego example, the offset gear is used to intermittently rotate the other gear. Usage not known.

17. Uni-directional drive is a gearbox that converts bidirectional rotary motion to unidirectional rotary motion. Used in ocean wave generators.

18. Camshaft converts rotational motion to reciprocating motion. The shaft contains one or more pointed cams. Used in piston engines to operate valves.

19. Intermittent mechanism is a device that regularly advances an object and then holds it in place. Note that this simple Lego device doesn’t hold the object in place. By combining it with a worm gear, it fulfills that behavior. Used in movie cameras and projectors to move the film.

20. Worm gear is a gear in the form of a screw. When combined with a spur gear, it produces high gear reduction. Only the worm gear can be the driver gear. Used in musical instruments for tuning the strings.

20 Mechanical Principles Combined in a Useless Lego Machine

ASMR videos don’t really do anything for me, but I could watch videos of gears and mechanisms doing their thing all day long. I watched this video of 20 mechanical Lego widgets being combined into one useless machine, absolutely rapt. Bevel gears, rack and pinion, camshaft, worm gear, universal joint, Schmidt coupling — this thing has it all.

A Lego Technic model (MOC) that demonstrates 20 different mechanical principles. You may call it a do-nothing machine or a useless machine, as all it does is rotate those beautiful mechanical principles. At the end of the chain is a slowly turning minifig statue. Available in two versions: Power Functions and Circuit Cubes.

List of 20 mechanical principles

1. Schmidt coupling transmits rotary motion between two radially displaced shafts. Used, for example, in printing industries to accommodate rollers whose distance changes often.

2. Constant-velocity joint (CV joint) transmits rotary motion through variable angles while keeping a constant speed. Used in cars between wheels and the drive shaft.

3. Universal joint transmits rotary motion through variable angles. Unlike the CV joint, this mechanism doesn’t keep a constant speed. The problem is partially overcome by connecting two U-joints 90 degrees out of phase, also known as a Double Cardan shaft. Universal joints are used in the long driveshafts of trucks.

4. Bevel gears transmit rotary motion at right angles. Used in car differentials.

5. Slider-crank linkage converts rotary motion to linear motion or vice versa. Used in automobile petrol engines between the piston and the crankshaft.

6. Sun and planet gear convert rotary motion to linear motion or vice versa. Similar to a crank but requires two revolutions from the driver gear to complete one full beam stroke. It was used in steam engines in the Industrial Revolution because the crank was patented.

7. Scotch Yoke converts rotary motion to linear motion or vice versa. Used in valve actuators that require a lot of torque.

8. Chebyshev Lambda Linkage converts rotational motion to approximate straight-line motion. Used in walking robots.

9. Chain drive transmits mechanical power from one place to another. Used in bicycles between pedals and the drive wheel.

10. Belt drive transmits mechanical power from one place to another using flexible material. Used in automotive engines to transmit power to an alternator, water pump, and other parts.

11. Constant-mesh gearbox is a type of manual transmission where a gear stick is used to select gears. A dog clutch slides on the main shaft and meshes with desired gears. Used in modern cars.

12. Oscillating direction changer is a device that periodically changes the direction of rotation of the output shaft. Usage not known.

13. Torque limiter is a device that protects equipment from mechanical overload. The Lego part (60c01) uses an oval-shaped center that slides against bending metal plates. Torque limiters are used, for example, in fishing reels.

14. Winch is a mechanical device to pull in or let out rope. Used in sailboats.

15. Rack and pinion convert rotary motion to linear motion or vice versa. It consists of one circular gear (pinion) and one linear gear (gear rack). Used in automobiles between the steering wheel and front wheels.

16. Offset gear is a spur gear where the shaft is mounted offset from the center of the gear. In this Lego example, the offset gear is used to intermittently rotate the other gear. Usage not known.

17. Uni-directional drive is a gearbox that converts bidirectional rotary motion to unidirectional rotary motion. Used in ocean wave generators.

18. Camshaft converts rotational motion to reciprocating motion. The shaft contains one or more pointed cams. Used in piston engines to operate valves.

19. Intermittent mechanism is a device that regularly advances an object and then holds it in place. Note that this simple Lego device doesn’t hold the object in place. By combining it with a worm gear, it fulfills that behavior. Used in movie cameras and projectors to move the film.

20. Worm gear is a gear in the form of a screw. When combined with a spur gear, it produces high gear reduction. Only the worm gear can be the driver gear. Used in musical instruments for tuning the strings.