What is Slider crank: Definition and 22 Discussions

A slider-crank linkage is a four-link mechanism with three revolute joints and one prismatic, or sliding, joint. The rotation of the crank drives the linear movement the slider, or the expansion of gases against a sliding piston in a cylinder can drive the rotation of the crank.
There are two types of slider-cranks: in-line and offset.

In-line: An in-line slider-crank has its slider positioned so the line of travel of the hinged joint of the slider passes through the base joint of the crank. This creates a symmetric slider movement back and forth as the crank rotates.
Offset: If the line of travel of the hinged joint of the slider does not pass through the base pivot of the crank, the slider movement is not symmetric. It moves faster in one direction than the other. This is called a quick-return mechanism.There are also two methods to design each type: graphical and analytical.

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  1. Eko

    Understanding Gas Dynamics in Piston-Crank Slider System

    I need help understanding what happens to the gas that is being worked by the piston, in the crank slider. My goal is to produce linear motion on an object up to a certain height and I'm wondering since the slider moves back during the rotation of the crank what happens to the object I'm trying...
  2. I

    Slider Crank Force Analysis: Understanding the Equilibrium Forces and Results

    I am in a mechanical design class that has been focusing on the slider crank mechanism. My professor tends to just provide derived equations without showing the analysis. I feel like I am missing out on some key understanding because of this. Specifically, I am trying to do what should be a...
  3. M

    Equation for the angular position of a slider crank mechanism

    Hi! I would like to know how I could define an equation for α with given the two lengths of the rods and angle theta (θ). I sketched the situation below, the problem arises when the rod Lab has pasts the 180 degrees. Like to hear.
  4. subatomicprincess

    Question about Slider Crank Mechanism problem

    I have attached my attempt. The only thing I keep getting wrong is the direction of V_(D/B). I know it is perpendicular to r_(BD) but, I never know if it is going upwards or downwards. In this case, I thought it was going downwards but when I checked the answer key, it had said it is going...
  5. bugdry

    Slider Crank Mechanism Torque Question

    I hope that it is okay for me to ask this here. It has been a long time since i did mechanism analysis. I have what I hope is a quick question. I calculate the torque required to rotate crank AB and therefore lift up the link BC to be 88lb-in. I assumed that link AB has no weight, no...
  6. bash1803

    Understanding Algebraic Solutions for Slider Crank Mechanism Calculations

    Hi Guys, I am currently working on an assignment for my uni. I don't want to post the question right away as I want to try to understand as much of the material as possible; but it seems what they have given me is a bit lacking. As such I was wondering if anyone could point me in the right...
  7. CameronRose

    Reducing the power required to drive a slider crank

    Hi folks, I'm currently working on the design of a triplex plunger pump. I have conducted an investigation into the loading of the pump at maximum operating pressure using an analytical method (free body diagrams) and using rigid body dynamics to validate. In both analyses the pump has been...
  8. Alistair McCheyne

    Slider Crank Magnitude and Direction of Force on Member AB

    Homework Statement Homework Equations The Attempt at a Solution https://scontent-lhr3-1.xx.fbcdn.net/v/t34.0-12/13140955_10156888508510486_863100825_n.jpg?oh=3f13a038f3dc053c7a10858aa62f6fc0&oe=57318819...
  9. Alistair McCheyne

    Slider Crank Mechanism Magnitude and Direction

    https://scontent-lhr3-1.xx.fbcdn.net/v/t34.0-12/13181084_10156883800920486_1357045350_n.jpg?oh=a39d7777f01c4aa06301c4f3d740de1e&oe=57301DBC Hi I am currently studying design engineering and my lecturer has left just before an exam. I really don't know how to find the magnitude and direction of...
  10. P

    Shaft and Pin Size of Slider Crank Mechanism

    Hi all, I am working on a slider crank mechanism for moving an object of about 100 kg back and forth 30 mm at about 600 rpm. I plan to attach the connecting rod onto a flywheel that act as a crank, or attach to a pulley (in case need to use a transmission system to reduce input speed, increase...
  11. thegreengineer

    Slider crank mechanism problem

    Before starting I want to say that this topic is from a subject I'm taking called vector mechanics. The subtopic dealt is called kinematics of rigid bodies. Homework Statement The wheel rotates around an axis. This point of reference of the center of the wheel is labeled as "A". This wheel...
  12. Y

    Instantaneous center of velocity for a inverted slider crank

    Homework Statement [/B] Find the instantaneous centers of the linkage below. Homework Equations # of ICs = n(n-1) / 2 The Attempt at a Solution [/B] From the equation above, there are 4(4-1)/2 = 6 ICs in this linkage. But one thing I don't understand is how there are 4 links when 2 and 3...
  13. J

    Inertial forces of a slider crank

    Homework Statement Hello, I have an exam later in the week and I'm trying to understand how to this problem. Homework Equations Sum of forces. Sum of moments. The Attempt at a Solution I broke the mechanism into 3 pieces, the crank, connecting rod, and slider and then began to analyze...
  14. H

    Maximizing Velocity and Acceleration in a Slider Crank Mechanism

    Homework Statement a) For the mechanism shown in figure 1 determine for the angle (45°): i) the velocity (VBO) of the piston relative to the fixed point (O). ii) the angular velocity of AB about point A. iii) the acceleration of point B relative to A. *Note: Link AB is horizontal when angle =...
  15. M

    Calculating Mass Moment of Inertia for Slider Crank | Explained

    Hi, I'm sorry my question is almost identical to an unanswered question here, but I was unable to reply to it (because it is old?). I want to have the mass moment of inertia 'I'of the block C, which will be a function of theta. I am ignoring the contribution from the links.Due to the...
  16. R

    How to calculate the torque of slider crank?

    As shown in this picture, if Fb, l (length of connecting rod), r (radius of crank) and θ is given, how to calculate the torque the slider crank? I know it can be a simple question for Mechanical Engineering majors, but I am an Electrical Engineering major and have very little knowledge in...
  17. M

    Position analysis of slider crank like mechanism using loop equations

    Hi Everyone, This is my first post so bare with me. Firstly, a bit of background about the problem. I am designing a near rear drive train for a formula student car which incorporates a chain tensioning device linking the differential to the rear of the chassis. Essentially I am wanting...
  18. B

    Slider crank mechanism. Help needed to find the velocity & angular velocity.

    Homework Statement The instantaneous configuration of a slider crank mechanism has a crank GH 10cm long, the connecting rod HP is 50cm. The crank makes an angle of 60 degree with the inner dead centre position and is rotating at 110 rev/min. Determine the velocity of the piston P and the...
  19. K

    F=ma applied to slider crank piston motion

    I'm struggling to apply F=ma to the motion of a slider crank, more specifically the piston. I want to find out how much force is nessesary to keep the piston in motion. Essentially, in the mechanism there is acceleration and deceleration, does that mean only at some points in the cycle there is...
  20. B

    Slider crank mechanism mass moment of inertia

    I need help solving a mass moment of inertia for a slider crank mechanism. I've done my best to sketch it in the attachment. This will be used for sizing of a motor. Homework Statement Link A has mass Ma and is located Acg distance from its pivot point Z Link B has mass Mb and is located Bcg...
  21. D

    Solving Slider Crank Problem: Tips & Advice

    I'm having trouble figuring out this problem. I know how to solve the problem if the angular velocity was known but there seem to be too many unknowns to be able to generate graphs. If anyone can offer advice that would be great.
  22. B

    Proving a 2D slider crank mechanism fits the Gruebler's Equation

    Homework Statement Need to prove that a slider crank mechanism fits the Grueblers eqaution, already done for a four bar mechanism no problem, however having some serious problems with the slider crank. If l is the number of links and j is the number of joints Homework Equations Grueblers...