Questions tagged [linkage]

A mechanical linkage is an system of connected bodies. The connections are called joints, that come in many flavors. Linkages allow you to design various path movements, speed profiles and force changes. The simplest possible linkage is a four bar mechanism and its special case the crank mechanism.

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Pivot material for linkage hinge?

*** modified design with new gas spring approach -I couldn't find shoulder bushing with large enough shoulder diameter so I will buy nylon tubing and cut them to lenght (Item 11) and add abs washer I ...
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1 answer
764 views

Is there a formula that relates the two angles in a crank rocker?

I'm working on a mechanism that requires a crank rocker - is there a formula that relates the angle (to some fixed reference; horizontal, vertical, whatever) of the driving "crank" to the ...
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Free body diagram problem: Linkage w/ magnets and friction hinge

I am a bit stumped on a IRL problem, which i simplified in the diagram below: There are left and right beams (gray) linked together by a friction hinge. The bottom beam (black) is connected to the ...
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35 views

I am too dumb to make Peaucellier–Lipkin linkage work

I tried in math.stackexchange.com and they send me here. First: Don't crucify me for not "doing math", or asking a dumb question. School was a long time ago, and lose what you don't use. My ...
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1 answer
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Analysing Bending in a Linkage Member

Context: I'm designing a linkage mechanism as part of a university robotics design project. From previous analysis, I have determined the forces and torques applied to each member at all points in ...
1 vote
2 answers
73 views

Why does this linkage calculate log?

From wikipedia, there's this animated GIF of a linkage. Question: How does it calculate log? All I see there are trig functions and circles. log doesn't show up in ...
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1 answer
50 views

Number of degrees of freedom of parallel mechanism

Can anyone provide me with the number of degrees of freedom (translational and/or rotational) at point P? Edit with my assumptions: The left picture shows the mechanism from the side and the right ...
0 votes
1 answer
64 views

Linkage Mechanism Doubt

I am unsure how I would solve this. I have tried to solve it and got -29.1 but my attempt was wrong. Could someone please lead me in the right direction or show me the way to solve this? Thank you.
1 vote
3 answers
289 views

How to generate a repeating semi-circle waveform using a mechanical linkage

How can one, in a smooth way, produce a semicircle wave, as opposed to a sinusoidal wave ? Imagining the machinery and linkages behind the movement. I mean the trace. For example a point fixed in ...
7 votes
3 answers
11k views

What method can I use to make a pivot point in an aluminum linkage?

I recently had a project where I made an aluminum linkage (similar to a scissor lift) operated by linear actuators. Aluminum pieces were fabricated from 6061 "standard" aluminum stock, 6mm (0.25 inch) ...
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0 answers
25 views

Online CAD resources for designing folding linkages?

I'm trying to design a space-saving, wall-mounted, fold-away workbench that has an auxiliary platform that folds out. The fold-away linkage to support the aux platform when it's folded out is taxing ...
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3 answers
121 views

Linkage between two vertically and horizontally offset wheels

I'm trying to drive a wheel with a radius of 20cm that is 20cm above the motor and horizontally offset by 20cm from the motor, similar to the following: I wonder what a good linkage might be for a ...
1 vote
2 answers
79 views

Mechanical linkage

I am not an mechanical engineer and I have a question about this laboratory rocker (https://www.thingiverse.com/thing:2948680/files). As I wish to reduce the height of the Model_Base.stl by half, by ...
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40 views

Mechanical Rotation about a Virtual Axis for Robot EOAT

I am working on a robotics application where we are erecting a cardboard box and stapling the ends shut. I need control over the "top" end flap to make sure it is out of the way for the rest ...
4 votes
4 answers
620 views

what college level teaches mechanical linkage design?

I'm 17 years old and learning first-year college math. What college level math do I need for mechanical linkage design? Can I learn designing and creating mechanical linkage without math but with my ...
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1 answer
48 views

Planar linkage design based on output curve?

I have the following path, The smaller radius isn't a hard constraint but the other dimensions are. I have a continuous rotation as the input & would like to design a planar linkage where the end ...
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"Snapping" shut/quickly closing gates

Suppose you have a set of two gates like so: Where you only want one of the gates to be in the "open" (non-blocking") position at any given time, this being the other possible state: ...
-1 votes
1 answer
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wingrotor rpm regulation; wind turbine regulation mechanism how it works?

First figure-Fig. 23. Regulating wingrotor, rotating in feeble wind, wingspan fully open. Second figure-Fig. 24. Regulating wingrotor, rotating in strong wind, wingspan contracting. ...
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What is the correct term for a joint stabilized by three points of articulation?

I am trying to find the correct term for this mechanical principle. I have a biomechanical system where two objects are anchored to each other along three points of articulation. These points are ...
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1 answer
34 views

Rotating a series of lights such that each one rotates more than the previous one

I want to rotate a series of lights that are all spaced evenly from each other with a single actuator such that when the first light rotates 1 degree, the second one will rotate 2 degrees and the ...
0 votes
1 answer
78 views

How to calculate the mechanical advantage of torque reaction arms (or balanced articulated arms)?

So, I was trying to figure out how to figure out how much force I would need to apply to these articulated arms in order to make them extend or "contract", but I can't figure out. I tried ...
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1 answer
60 views

How to achieve sliding motion like this between two blocks?

I want to make a construction of two boxes, that by default would be stacked one on top of the other, but linked in a way that would allow the top box to slide off and then move down so that they are ...
0 votes
1 answer
59 views

How to do linkage analysis for a two-arm lever?

I am not a mechanical engineer and am hoping someone can explain in simple terms how to do a linkage analysis for a two-armed lever. An example of such a linkage is shown below in the illustration of ...
-1 votes
1 answer
439 views

Why is Scotch-Yoke mechanism not used for internal combustion reciprocating piston engines?

Regarding piston acceleration variations due to the geometric nature of crankshaft and connecting rod motion, in relation to connecting rod length and bore to stroke ratio. Why is Scotch-Yoke ...
2 votes
3 answers
1k views

Transfer horizontal movement into vertical movement

I would like to transfer horizontal swaying movement of a tree into oscillating vertical movement. How to do it? It does not have to be ideal perpendicularity or straightness. More or less efficient ...
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214 views

What is the effect of caster angle in automobiles? What will happen if we use neutral caster?

What is the effect of caster angle in automobiles and what will happen if we use neutral caster? We study that positive caster makes vehicle more stable at high speeds. It increases lean while ...
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1 answer
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Is the DOF for a robot mechanism invariant if it is not in a different configuration?

I understand that if the robot is reconfigured, it can potentially change the DOF, but would the degrees of freedom for the robot also change if specific links were fixed and as such specific joints ...
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1 answer
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Summing Displacements of two Cranks and Sliders

Is there a linkage mechanism allowing the summation of the throws of two crank and slider mechanisms oriented next to one another in order to control an output slider with a motion equal to the summed ...
3 votes
1 answer
108 views

What would you call this mechanism and how can I calculate the forces involved

So I have an assembly with two pins sliding in two groves. First I would like to know if there's a name for this so I can do some more research. Second, if the assembly is standing up so that the top ...
4 votes
3 answers
425 views

Linkage of two shafts that need to rotate different angles

I have two switches that have different throw angles the switches have shafts coming out of them which are connected the the cams that can be seen in the attached pic. One needs to rotate 95 degrees ...
0 votes
2 answers
166 views

3D linkage design - terminology

I am designing an animatronic head, which has five degrees of freedom: pitch, roll and yaw for the head part, and pitch and yaw for the neck part. However, the yaw movements for the head and neck are ...
5 votes
4 answers
2k views

Rotation around an axis outside of the mechanism

I want to design a system of linkages that will allow me to rotate the green element around the blue point/axis without entering the red circle. The green triangle to go fully around the blue point. I ...
3 votes
3 answers
1k views

How do folding barriers work?

With folding barriers like the one below, how does the orange bar get turned by the green mechanism? What's inside the yellow triangular part? https://www.youtube.com/watch?v=LF8kSTCZIxw
2 votes
1 answer
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What is this bistate linkage?

I've found this video on YouTube: https://youtu.be/hWK8Gv0JHqk?t=220 Watch from 3:40 to 4:20. I'd like to learn more about this linkage that makes that link alternate between hitting and missing ...
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3k views

Toggle position of a fourbar slider-crank

In the fourbar mechanism as in the following picture, I have to find the toggle position, the sliding distance and the time ratio. Here is my understanding/plan to do this: The toggle positions ("...
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115 views

Static load analysis for four-bar linkage?

I am facing a difficult question and can't find answers anywhere else. What on the left is a hydraulic ram, it's pushing the box in the centre to move upward, while the four-bar linkage attached on ...
4 votes
1 answer
19k views

GIM Mechanism Software (Kinematics / Analysis / Synthesis)

I've recently discovered a very awesome software tool for the synthesis and analysis of mechanisms. The tool is called GIM, from Faculty of Engineering in Bilbao, Department of Mechanical Engineering,...
7 votes
2 answers
1k views

Design of a Four-Bar Infinity Coupler Linkage

How can I control a Four-Bar Infinity Coupler such that it does not accidentally become a Paralellogram Linkage? It seems to me that, when the bars are all horizontal, gravity could change the ...
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66 views

Is there a spherical joint equivalent to a 4 bar linkage?

In a 4-bar linkage, all the joints are regarded as hinge joints. However, when I searched "spherical 4-bar linkage system", I didn't get a 4-bar system with spherical joints but instead a 4 bar system ...
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217 views

Analytical six-bar linkage trajectory solution

Six-bar linkage is shown on the image: It has one degree of freedom, so if one of the variables is constrained, it's possible to calculate the positions of all the joints. In this specific case the ...
4 votes
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2k views

How to calculate the coupler length in a crank rocker mechanism

I'm trying to learn a bit about building kinematic mechanisms by building a small project. The goal is to be able to open and close a box programmatically via a servo motor. I have a small box that ...
1 vote
1 answer
412 views

Calculating force exerted on plate by link

I am currently involved with a project using a mechanism similar to that seen in 'table tilters' and we are struggling to work out how to begin resolving the forces. The image shows the state we are ...
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What is the correct mathematical approach to this linkage problem?

I have a linear actuator with 52 millimeters of travel. I have a set of linkages with specific dimensions as shown in the images below, to which this actuator will be attached. The REF dimension is ...
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1 answer
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How to quickly design and simulate crank based mechanisms? [closed]

I'm doing a project on Theo Jansen's Mechanism, where I have to modify the mechanism. What is the most efficient way to design these mechanisms? Is there any good software where I can just draw the ...
2 votes
0 answers
34 views

Gear design for symmetrical opening of two parts

I'm trying to build a lamp which has about 20 identical layers stacked on top of each other. There is a central spine and, on each level, a pair of arcs attached to the spine that are hinged and which ...
0 votes
1 answer
80 views

What are a few low-cost options for building linkages?

I'm working on a project trying to combine a pantograph linkage with a four-bar linkage. I'd like to build it out of relatively at-hand materials (AKA, nothing requiring a machine shop), and I'd like ...
1 vote
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402 views

Synthesis of 5 bar mechanism

I'm working on my university project but I can't find a proper synthesis method for 5 bar mechanism. I'm working on underactuated mechanism. It's a slider crank with the connecting rod divided into 2 ...
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2 answers
5k views

Difference between Linkage, Kinematic chain, Mechanism, Mechanical element, Mechanical machine and their precise definitions

Recently I started to study about "Design of mechanical machinery". Since I am a person who is very sensitive about words I want to know the difference between these notions and their precise ...
1 vote
1 answer
571 views

How to build a pivot linkage for a robot.

I have asked this question in 3DPrinting.stackexchange forum but got no answer answer. Please take a minute to see if you can help. I am building a simple RWD vehicle using 3d printer parts. See the ...
2 votes
2 answers
154 views

Lengths of Connectors in Steering Linkage

Below is a picture 4-wheel vehicle steering linkage. I figured that in order to steer correctly $(W+D)tan\theta_1=Dtan\theta_2$ where $\theta_1$ is the angle of the outside front wheel, $\theta_2$ is ...