Levers & Linkages Flashcards
To learn about different levers and linkages
What is the effort in terms of levers?
The input force exerted on the lever
What is the fulcrum/pivot?
The point around which the lever acts
What is the load in terms of levers?
The force of the object that needs to be moved
How many classes of lever are there?
3
What does a first order lever look like?
The fulcrum is positioned between the load and the effort:
What does a second order lever look like?
The load is positioned between the fulcrum and the effort:
What does a third order lever look like?
The effort is positioned between the fulcrum and the load
What type of lever is this?
First order lever
What type of lever is this?
Second order lever
What type of lever is this?
Third order lever
What are 3 examples of first order levers?
• Scissors • Seesaw • Crowbar
What are 3 examples of second order levers?
• Bottle opener • Wheelbarrow • Nutcracker
What are 3 examples of third order levers?
• Tweezers • The human arm • A fishing rod
How can you reduce the effort required to lift the load of a first order lever?
Move the fulcrum closer to the load
How can you reduce the effort required to lift the load of a second order lever?
Move the load closer to the fulcrum
What is the difference between third order levers and first and second order levers?
Third order levers do not have the mechanical advantage of first and second order levers. The effort is closer to the fulcrum than the load, meaning that the input force is greater than the output force.
How are linkages made?
By joining together levers
What do linkages do?
Linkages can change an input motion and force into an output motion and force. They often transmit force and motion at a distance from the initial input.
What do push/pull linkages do?
A push/pull or parallel linkage creates an identical parallel motion at the output
What do bell crank linkages do?
A bell crank linkage changes the direction of motion through 90°
How do you change the magnitude of a force with a reverse linkage?
• When the pivot is an equal distance from the input and output levers, the output force is equal to the input force • When the pivot is closer to the output lever, the output force is greater than the input force
What type of linkage is this?
Push/pull linkage
What type of linkage is this?
Bell crank linkage
What type of linkage is this?
Reverse linkage
What is the output force like in relation to the input force with this reverse linkage?
The output force is greater than the input force
