06.3 Kinematic Analysis - Orange Juicer
For our analysis, 0 degrees is when L2 is parallel with the slider’s motion and closer to the press. All of the analysis has been done for the chosen motor. Our project is composed of two main mechanisms: the press, made of a slider crank, and the ejector, made up of a sprocket-chain-cam-spring-system.
Main parameters:
L2 = 5 cm
L3 = 20 cm
Offset (L4 ) = 3.75 cm
Tin = 90 kg*cm = 882.5985 N*cm
Motion Profiles of Press:
These profiles show the displacement, velocity, and acceleration profiles of the slider when the angular velocity of the crank is 1 rad/sec and there is not crank angular acceleration. From the displacement profile, it can be see that the slider travels about 10 cm throughout the process which is about double of half of a mandarin orange, which has a total height of about 8 cm. This means that at the furthest point from the the press base, the slider clears both the rounded part of the press base and a half a mandarin that is being placed on the base.
Mobility Calculations for Press:
Full Rotation Condition for a Slider-Crank: L3 > sqrt(L2 2 + L4 2) => 0.2 > 0.0625
Grubler Equation: M = 3(4 - 1) - 2(4) - 1(0) = 1 DOF
Force Analysis of Press:
From experimentation with squeezing an orange using the orange juicer that we bought and is attached to this prototype, we learned that the ideal minimum amount of force to squeeze the mandarin is 155 N. From the force analysis, we can see than the minimum force applied to the end of the slider from the input torque on the crank from the motor we have sourced is about 160 N, with the force being higher at full extension.
Slider Animation:
Ejector Mechanism:
Although the ejector mechanism analysis is outside the scope of this course, we know that the ejector slides along a straight line with a max displacement of 33 mm. With our spring constant of 7.117 N/cm, this means that the pusher has the force of 25.4 N to push the orange peel.