-Enable
us to control movement of objects.
Ratchet & Pawl:
-Gear system.
-Change movement some way.
-Ratchet screwdriver & seat belt.
-3
parts: Gear, axis, pawl.
Disc Brake:
-Works
on a hydraulic system.
-Solid metal wheel disc.
-Two pads on either sides.
-Cylinder.
Part of systems & controls:
-Systems = combination
of parts that works together.
-Systems = input
(press brake handle), process (pressure in piston) and output (blocks press on
wheel).
Bicycle Brake:
-Slow or stop a
bicycle.
-Cantilever
brakes = Two cables
-Main cable center line of bicycle.
-Transverse cable = Connects cantilever (top of the tire).
-Pivot = central point on
which mechanism turns.
Car Fluid = bicycle brake cable
Where will you
classify the following braking
systems:
-A vehicle: pneumatic?
-A bicycle: mechanical?
Pressure = small brakes = reasonable force =
friction.
Cleat:
-Metal/wood
shaped on boat/ship for ropes.
Unit 4: Mechanical systems control
Combination
of levers, linked levers, wheels, cams , pulleys and/or gears.
Gear: Wheel with cogs that mesh with another gear.
Bevel
gears: Gear with 45°
sides with teeth cut
around
them.
Helical Worm gears: Gears
where teeth cut in a spiral
along a shaft.
Rack and pinion
gears: Gear
wheel and toothed bar to
change a rotary movement
into a linear movement.
A round gear moving along a straight toothed
rack.
Spur gears: grooved
teeth with simple design
Spur Gears:
Idler gears: gear
between others.
Purpose: synchronise (let
something occur with exact coincidence in time and rate) .
Bevel gears:
Rack and pinion gear:
Examples: motorized gates; steering mechanisms and cork screws
Helical worm gear:
Cut in spiral along a shaft (cylinder).
Reduction in
speed and increase in force occur.
- Use in motor gates
