Mechanical Control Flashcards
(20 cards)
What is reciprocating motion?
Back and fourth movement.
E.g. piston
What is oscillating motion?
Back and fourth movement in a swinging motion.
E.g. windscreen wiper
What is rotary motion?
Circular motion.
E.g. clock
What is linear motion?
Motion in a straight line in one direction.
E.g. a lift
What is a class 1 lever and give an example.
Fulcrum in the middle with load and effort on either side
E.g. see-saw
What is a class 2 lever and give an example.
Load in the middle with the fulcrum and the effort on either side.
E.g. wheelbarrow
What is a class 3 lever and give an example.
The effort is in the middle with the load and the fulcrum and the load on either side.
E.g. tweezers
How to remember levers?
FLE
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What is the difference between a flat follower, a roller follower and a knife follower?
A flat follower is perfectly flat faced.
A knife follower has a sharp edge for following detailed cam profiles.
A roller follower has reduced wear due to the rolling motion.
Give an advantage of a flat follower.
The push exerted on a flat follower is less than other types of follower.
Give an advantage of a roller follower.
Causes less wear, so can be used in situations where wear causes issues, for example jet engines.
Properties of a pear shaped cam.
Followers only move for about half the cycle.
Properties of an eccentric cam.
An eccentric cam causes a smooth and constant rise and fall with no pause
Properties of a snail cam
A snail cam allows for a sudden and sharp drop in the height of the follower, with a slower, smoother rise.
Properties of a heart shaped cam.
The follower rises and falls around a heart shaped cam at a constant speed, without a resting period. Also known as a constant velocity cam.
Give the properties of a round belt.
The have a small drive force
Can be used where the belt has to turn through 90°.
Give the properties of a toothed belt.
Has teeth cut into it.
Low chance of slipping
Quietest of pulleys
Give the properties of a V-belt.
Large area of belt in contact with pulley
Increased friction
Larger drive force
Equation for gear ratios
Gear ratio= number of teeth on driven gear
——————————————
number of on driver gear
Equation for transmission speed.
RPM Driver. No. Teeth driven
————— = ——————————
RPM Driven. No. Teeth driver
