Low Cost Automation Tutorial

#252 Basic Elements of Automation Clever Mechanisms: Rotary-Linear Motion Conversion Mechanism 2

Category : Hints on designing

September 2, 2016

In the previous volume, we introduced a mechanism that is compatible with various models and equipped with an adjustable sliding stroke feature for the slider, as an application example of the slider-crank mechanism. In this volume, we will look at an automation clever mechanism that has a structure whose rod/slider parts in slider-crank mechanism can be exchanged in a simple operation.

[Fig] illustrates the mechanism with exchangeable rod/slider parts. A U-shaped hook is installed so that the tip of the rod can be easily connected to the hinge pin at the hinged end of the crank.

fig

(1)Application examples

For simple automation devices or fixtures made compatible with multiple models by connecting a processing unit to the slider unit, exchanging the slider unit after preparing a processing unit off-line can minimize the time required for model switching.

(1)Application examples

	1.	Drive mechanism of the squeegee unit for a simple screen printing machine: Description: When materials are replaced owing to the pot life or when printing materials are replaced, it is possible to switch models quickly if you remove the slider parts with the squeegee integrated and exchange it with the slider parts with its squeegee position adjusted off-line.
	2.	Simple press mechanism with multi-model compatibility

(2)Precautions for application

Because of this simple coupling method, where only a U-shaped hook is placed over the rotating crank, this mechanism is not compatible with the following types of motion:

	1.	A high-speed rotating crank. The self-weight of the rod may not be sufficient to follow the motion.
	2.	A large rotating radius. Motion from the crank shaft to the U-shaped hook will not be transmitted effectively in some areas.
	3.	Motion involving unstable speed or oscillation. The U-shaped hook may fall off.

(3)How to use a slider-crank mechanism

An area with less varying speed or with a linear trend of speed will generally be selected for use.

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