The slider crank is a very common linkage that is found in a variety of machines. The most recognizable version of the slider crank is found in an engine in the form of a crank shaft, connecting rod, piston, and cylinder. This mechanism also comes in different forms called slider crank inversions.
The slider crank has four inversions. An inversion is when a different link is fixed.
Inversion 1 is the recognizable engine linkage. Link 1 is the engine block, link 2 is the crank shaft, link 3 is the connecting rod, and link 4 is the piston.
Inversion 2 is also a common linkage. It's often found where link 1 is a linear actuator such as a hydraulic cylinder. An excavator arm has three of this slider crank inversion: one to lift the arm attached to the machine, one to move the bucket arm, and one to curl the bucket.
Link 3 can also be the driving link and rotate 360 degrees.
Inversion 3 has link 2 as the driver and can provide complex motion.
Inversion 4 is most recognizable as a hand operated water pump. If link 2 is extended past the joint connecting links 2 and 3, this is the pump handle. Link 1 can also be the driver in the form of a linear actuator, although care must be taken to avoid excessive side loads on link 1.
Slider Crank Inversions Summary
As you can see, the slider crank is a versatile mechanism the is found in a variety of machines. The slider crank inversions provide great flexibility in performing a wide range of tasks.
MEboost can synthesize and analyze all slider crank inversions. The link numbers in this article were kept the same for each inversion to illustrate how each linkage is different. MEboost uses the convention that the fixed link is always link 1.