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Hart's inversors are two planar mechanisms that provide a perfect straight line motion using only rotary joints. They were invented and published by Harry Hart in 1874–5.
Hart's first inversor, also known as ''Hart's W-frame'', is based on an
Mecanismo de Hart (2).png,
Mecanismo de Hart.png,
bham.ac.uk
– Hart's A-frame (draggable animation) 6-bar linkage Linkages (mechanical) Linear motion {{engineering-stub Straight line mechanisms
Hart's inversors are two planar mechanisms that provide a perfect straight line motion using only rotary joints. They were invented and published by Harry Hart in 1874–5.
Hart's first inversor, also known as ''Hart's W-frame'', is based on an antiparallelogram
In geometry, an antiparallelogram is a type of self-crossing quadrilateral. Like a parallelogram, an antiparallelogram has two opposite pairs of equal-length sides, but these pairs of sides are not in general parallel. Instead, sides in the lon ...
. The addition of fixed points and a driving arm make it a 6-bar linkage. It can be used to convert rotary motion to a perfect straight line by fixing a point on one short link and driving a point on another link in a circular arc.
Hart's second inversor, also known as ''Hart's A-frame'', is less flexible in its dimensions, but has the useful property that the motion perpendicularly bisects the fixed base points. It is shaped like a capital A – a stacked trapezium and triangle. It is also a 6-bar linkage.
Example dimensions
These are the example dimensions that you see in the animations on the right.See also
*Linkage (mechanical)
A mechanical linkage is an assembly of systems connected to manage forces and movement. The movement of a body, or link, is studied using geometry so the link is considered to be rigid. The connections between links are modeled as providing i ...
* Quadruplanar inversor, a generalization of Hart's first inversor
* Straight line mechanism
A straight-line mechanism is a Mechanism (engineering), mechanism that converts any type of rotary or angular motion to perfect or near-perfect straight-line motion, or ''vice-versa''. Straight-line motion is linear motion of definite length ...
Notes
References
External links
bham.ac.uk
– Hart's A-frame (draggable animation) 6-bar linkage Linkages (mechanical) Linear motion {{engineering-stub Straight line mechanisms