Please enable JavaScript.
Coggle requires JavaScript to display documents.
MECHANISMS, Moving people from one side to another
Telling the time
…
MECHANISMS
LINEAR MOTION MECHANISMS
-
-
-
Levers
Class 2: The load is between the effort and the fulcrum. The effect of the effort is always multiplied.
Class 3: The effort is between the fulcrum and the load. The effect of the effort is always reduced.
Class 1: The load and the effort are on opposite sides of the fulcrum. The effect of the effort applied can be multiplied or reduced depending on where the fulcrum is in relation to the load.
WHAT ARE THEY?
They are devices that transmit and convert forces and motions from a driving force to an output element. They make some tasks easier.
Some examples are the gear and the chain of a bike, the pulley used to take out water from the well, the lever of a seesaw,...
The most important part of all is the motor or driving force that starts the movement. It can be spring, electric motor or our own muscles. The movement produced by the motor can be transformed and its transmitted via different mechanisms to the output elements.
-
-
-
-
- Moving people from one side to another
- Telling the time
- Entertaining children in a park
- Raising and lowering objects
Rigid bar that is used with a point of support or a fulcrum, the effort is applied on one end of the lever with the aim of counteracting the load which acts on the other end of the lever.
Wheel that has a groove for a rope, chain or belt to go round it, it rotates around an axel that is fixed to an immobile surface. This reduces the load when effort is applied.
Two pulleys, one is fixed while the other can move in a linear direction.
Set of fixed and moveable pulleys, often called a block and tackle. If you add more pulleys is more complex but is less the effort you have to make to move the load.
-
-
-
-
-
-
-
-
-
- This is made up of two or more wheels that are in contact.
- Wheel is called the primary drive wheel. When it moves it turns or drives the output wheel, causing it to move as well.
- The output wheel rotates in the opposite direction to the primary wheel. If we use more than two wheels, each one rotates in the opposite direction of the one next to it.
- These are two pulleys or wheels that are certain distance appart.
- Their axels are parallel and they rotate simultaneously because of the belt.
- The rotation of one axel is transmitted to the other via the connected pulleys.
- The two pulleys and axels rotate in the same directon.
- Cogwheels are sets or wheels that have teeth called cogs.
- They mesh together so that one wheel moves another. They transmit a rotary motion between the two connected axels, which can be parallel, perpendicular or oblique.
- All the teeth need to be the same shape and size.
- The two wheels and two axels rotate in opposite directions.
- These is a screw that moves a helical cogwheel which is set perpendicular to the screw.
- Each time the screw rotates the gear moves forward as many teeth as grooves in the screw.
- This is used to reduce velocity as well as serving as a braking system.
- These are two cogwheels with parallel axles that are a certain distance apart.
- They rotate simultaneously by means of a metal chain or a toothed neoprene belt stretched over both wheels.
- The chain transmits the rotary motion of axle 1 to axle 2 via gears 1 and 2. The two gear rotates in the same directon.
- This system transmits greater forces without losing velocity because the chain is attached to the gear teeth so there is no slippage between chain and the wheel.
The links in the chain or the teeth in the belt have to be the same
size and shape as the gear teeth.
- This is a system of pulleys or wheels with a belt.
- There are two or more pulleys.
- The rotary motion of axel 1 is transmitted to axle 2 via the streched belt that connects them.
- Pulleys 2 and 3, attached to the same axle, rotate at the same velocity.
- The motion of pulley 3 is transmitted to pulley 4 via the belt that connects them. All the pulleys rotate in the same direction.
- The rotary motion of the first wheel drives the second wheel.
- Wheel 3 rotates at the same time of wheel 2 and drives wheel 4.
- When there are two wheels, each connected geared wheel rotates in the opposite direction to its partner.
This uses a pinion and a rack that, when the pinion rotates, the rack advances in linear motion. It is a reversible mechanism.
This consists of a bolt or threaded bar and a nut that has the same interior diameter as the diameter of the bolt. If the bolt rotates and the nut can't turn, the nut moves in a linear motion, but if the nut rotates in a fixed position, the bolt rotates in a linear motion.
This consists of a crank handle attached to the axle of a cylindrical drum, the crank is used to turn the winch. The winch consists of a drum that rotates on its axle. It's used to lift or pull an object.
This is composed by a carnk and a rod named link. The rod has articulated joints at each end connecting it to the crank and the slider. the slider outputs reciprocating motion. As the wheel rotates, the crank transmits the rotary motion to the connected rod, which moves with a reciprocating motion, it can work in reverse, too.
This is a set of connecting rods attached to a jointed axle. Eah of the joints of the axle act as a crank. It transforms the rotary motion of an axle into a reciprocating motion with different connected rods moving at different times
This is a rotating shape that pushes a "follower". We can change the shape and the usable profiles that are more or less pointed to produce more complex movements. It transforms rotary motion into reciprocatmg motion in the follower or bar. This is touched and moved by the edge of the cam when it rotates. A set of cams fixed on the same axle is called a camshaft.
This consists of a wheel with an off-centre rotation axle. It transforms the rotary motion of the wheel into reciprocating motion in the connecting rod. The distance between the centre of the circumference and the rotation axle of the cam is called eccentricity.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
