A backdrive is a component used in reverse to obtain its input from its output. This extends to many concepts and systems from thought based to practical mechanical applications.
Not every system can be backdriven. A DC
electrical generator
In electricity generation, a generator is a device that converts motive power (mechanical energy) or fuel-based power (chemical energy) into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas ...
can be implemented by backdriving a DC
electric motor
An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...
, however a
worm drive
A worm drive is a gear arrangement in which a worm (which is a gear in the form of a screw) meshes with a worm wheel (which is similar in appearance to a spur gear). The two elements are also called the worm screw and worm gear. The terminolo ...
works only in one direction.
Example: A CNC vertical mill has a vertical lead screw on the Z-axis. A low lead screw pitch (i.e. 5 turns per inch or fewer) means when the driving motor power is removed such as by turning the machine off, the weight of the spindle will cause the lead screw to rotate as the spindle motor falls down. The solution to prevent back-driving is to use a finer (higher) lead screw pitch (i.e. 10tpi or greater) or have a locking mechanism.
Another example is the practice to add
swivel caster
A swivel is a connection that allows the connected object, such as a gun, chair, swivel caster, or an anchor rode to rotate horizontally or vertically.
Swivel designs
A common design for a swivel is a cylindrical rod that can turn freely wi ...
wheels on a
mobile robot
A mobile robot is an automatic machine that is capable of locomotion.Hu, J.; Bhowmick, P.; Lanzon, A.,Group Coordinated Control of Networked Mobile Robots with Applications to Object Transportation IEEE Transactions on Vehicular Technology, 2021 ...
, so that humans can push away the robot when it comes too close.
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Mechanical engineering