Brief
Scissor mechanism uses linkages connected together in a cross-X pattern, this type of mechanism can folded to be a very short height and when the linkages start moving by actuators, the mechanism can extend to reach a long distance very easy.
** The scissor mechanism has been controlled by a different types of actuators [Hydraulic, Pneumatic, and Electric].
Conceptual Model
This is the conceptual design model of scissor lifting elevator, in this model the Driving Mechanism is a screw and nut which is convert the rotation movement from hand wheel to a linear movement.
This linear movement can activate the mechanism by changes the driving dimension which is make a change in the driven dimension directly.
Mechanism Calculations
Input/Output Equation
This equation mainly to control the dimensions of the mechanism, where the Input and Output formula can answer the question "How many turns required to reach a certain height?".
The output of scissor mechanism is height length [X], and the Input is the number of turns in hand wheel [N].
So, the final equation has 2 variables
- N : number of turns.
- X : required height of mechanism.
Just enter the height you needed from scissor mechanism the formula can tell you how many turns you need to achieve this height.
** you can use a DC motor instead off handle and make it automated ;)
Force Analysis
This equation tells you what is the enough linear force [F] has been generated by the lead screw required to move the load [W] that applies on the scissor mechanism?
The maximum force needed when the angle theta is minimum.
So, take in your consideration the worst case scenario to calculate the force correctly.
Useful Links
** For more details and how to proof this formula Click on this link
** For the torque needed of lead screw to generate the linear force follow this online calculator
Download the Scissor Lifting Mechanism Model from Here.
** Watch animation Video
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