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Questions tagged [linear-motion]

88 questions
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Lifting a cabinet using actuators or scissor lift

Disclaimer: I am not an engineer - just a DIY guy looking for some advice or help please, so please forgive me if I use incorrect terminology :) I am building a cabinet that has a hidden inner cabinet that is meant to rise up out of the former. The…
maGz
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Quick return mechanism for spring-loaded screw

I am looking for a way to convert rotary motion to linear, but it should take less energy to get back to initial position than when going from initial position to the end position. Specifically, a screw mechanism pushes a spring with multiple of…
PSz
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Off-centre actuation

I'm trying to lift a platform with several guides using a linear actuator, but off the centre as follows: The load on the platform will be around 100kg, which is just within the linear actuator's 120kg load capacity. The platform will be around…
John M.
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Linear actuator behind lifting boom

This is a follow-up on my previous question here: Sizing a motor for a floor jack-like mechanism The floor jack setup is clearly inefficient when it comes to electric actuators. Something similar to a mobile crane would work better, as I'd benefit…
John Lane
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Ideas for mechanism for quick reciprocating motion - a 'truly' mechanical switch

I need a mechanism to switch the vertical position of an assembly in as square a profile as possible - i.e. a normal crank mechanism produces a sine wave profile, to explain myself better. I've seen some quick return mechanisms (and this) - these…
Oliver Walters
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Raise/Lower 350lb Sawmill Head 12v Motor Specs

I am new to this site and have a problem to solve in an area that I’m pretty lost in. I can usually figure stuff out with the help of the internet and some digging but not getting real traction so hoping some folks smarter than me can help! I’ve…
SawmillBuild
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Single linear actuator lifting mechanism

I have inherited a DIY build and I have some doubts about its design. Have a look at the following diagram: 1 is the linear actuator. It's quite beefy 2000 lbs 12" stroke. It is installed in an aluminium channel. 4- Is a carriage, essentially a box…
John Lane
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Difference between Linear Force and Force about an Axis

I am confused between How forces work when applied in singular linear direction vs Force Applied to a continuous mass about an axis(example to rotate it). Example 1: Consider an object of mass $m$ which is lying on a table with friction coefficient…
german_wings
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Linear guide ball bearings

I'm planning to drive a small linear guide (4cm long) with a servo in a setup like this: I wonder if the ball bearings inside would sustain too much stress due to the vertical forces exerted by the links whilst driving it linearly. AFAIK ball…
John M.
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Design Input: Rotary motion to Linear motion, What system should I choose?

I am posting this here because of the multidisciplinary knowledge needed to tackle this issue. Problem: I have to make an electromechanical device that is required to have controllable (downward) piston strokes, that can up to deliver 500N of force…
Jake
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How to solve this linear motion problem?

Context: I have a lead screw rod, nut and a pulley aligned vertically. The nut is attached on top of the pulley so their respective bores are aligned and the rod is arranged so that it is threaded through the nut but its diameter is smaller than the…
kp122
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Dynamics of a rigid body in a system of two linear drives

I've been trying to solve the dynamics of this system for quite a while, but cannot seem to get the right answer. I've tried solving it with Lagrangian method but I am not so confident with the equations I'm getting. Firstly, looking at the picture…
Bob Kim
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Converting Linear Motion into rotary motion

I'm looking at designing something using the same mechanism used in this pepper grinder. As far as my knowledge goes, it is converting vertical Linear motion (the push button) into horizontal rotary motion (the ceramic grinder). I would like to…
Beau Birkett
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Simple mass spring damping system sizing K, and C factors

I have come across a problem, which has troubled me for some time now. What needs to be done is the following: A mass on a rod 0.6m (mass less) has a mass of 1 kg attached at the end of it. The rod needs to be rotated 60°, within t=120 sec (see…
mioumitsou
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Method to achieve a constant force no matter the actual velocity when under load

So, this might be a somewhat strange need, as I don't seem to see many resources on this. I'm trying to create a device where I can set an amount of force for it to generate, and when it would behave as such: If there is no or only a small opposing…
Jason Long
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