Movement Ratio
A machine is a device that can change the magnitude and line of action of a force.
Examples are
- pulley systems
- gear systems
- screw-jacks
A simple machine amplifies the input force (effort) to a larger output force (load).
Movement Ratio
The movement ratio (or velocity ratio) of a machine is defined as the ratio of the distance moved by the effort to the distance moved by the load. Movement ratio can be expressed as
Mr = se / sl
= velocity ratio (1)
where
Mr = movement ratio
se = distance moved by the effort (m, ft)
sl = distance moved by the load (m, ft)
Machine Efficiency
The efficiency of a simple machine is defined as the ratio of the force ratio to the movement ratio and can be expressed as
μ = Fr / Mr (2)
where
μ = machine efficiency
Fr = force ratio
Related Topics
• Dynamics
Motion of bodies and the action of forces in producing or changing their motion - velocity and acceleration, forces and torque.
• Mechanics
The relationships between forces, acceleration, displacement, vectors, motion, momentum, energy of objects and more.
Related Documents
Conn-Rod Mechanism
The connecting rod mechanism.
Force Ratio
The force ratio is the load force versus the effort force.
Motors - Speed vs. Pulley Diameter
Pulley (Sheave) selection charts for motors ranging 850 - 3450 rpm.
Pulleys
Pulleys, blocks and tackles.
Ratios and Proportions
The relative values between quantities - ratios and proportions.
Screw Jack - Effort Force vs. Load
Screw jacks and effort forces.
Toggle Joint
A toggle joint mechanism can be used to multiply force.