# Questions tagged [linear-motion]

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140 views

### 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 ...
42 views

### 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 ...
22 views

### Linear solenoid mount

I have a linear solenoid with a tapped M3 hole at the end of the plunger, like this: I need to connect this plunger to a lever, so I want to add a mount which has a connection something like this: ...
40 views

### Linear motion with triangle profile

I am looking for a way to generate a linear motion with a triangle motion profile for my hobby project. The travel distance should be 6cm (so 12 cm for round-trip) with constant speed 1.2 m/s or ...
62 views

### Is a pneumatic cylinder in general a linear or rotary actuator?

I've just begun to learn pneumatics and I'm really confused where the pneumatic cylinder falls under in the categorization of what kind of mechanical motion it is suppose to produce. I've seen one ...
399 views

### How do I calculate the ideal travel distance of the ball screw per revolution of the stepper or per step for the following hardware?

Question How do I calculate the ideal travel distance of the ball screw per revolution of the stepper / per step for the following hardware (I believe this is called the lead)? Background I have a pre-...
56 views

### If aboard a train being driven along a track by centripetal force, would it feel like you were on a regular straight track?

Question: If aboard a train being driven along a track by centripetal force, would it feel the same as if you were on a regular straight track? I hope this isn't subjective, I think there is a right ...
43 views

### How much force can an acme lead screw handle?

I have a stepper motor that claims 425 oz*inches torque. I want the lead screw to span 2' supported on both sides. I'm trying to decide what diameter lead screw is strong enough to not be damaged by ...
71 views

### In circular motion , why do we say this is centripetal acceleration

Let us say a particle is moving in a circle with Uniform circular motion . Then , if I take an equation like this . $\theta$ = S(Arc length or Total distance covered ) / Radius of circle *( time ...
38 views

### Did not understand this regarding angular velocity

It says $V\sin \alpha$ (component of velocity perpendicular to OP) is the cause of angular displacement. How is it? if only $V\cos \alpha$ existed, we need not turn over head to always to look at a ...
11 views

### Calculating Gearing Ratio from Constrained Rotational Linear Arc and Horizontally Opposed Rotation

I'm 3D printing an aircraft throttle unit as a POC and am trying to calculate the gearing ratios that are required in order transfer the full range of linear motion into a directionally opposed sensor ...
64 views

I'm currently developing a linear motion system which will have to withstand a large offset load (see image below). There will be two rails, each with a carriage on, which will be connected by a beam/...
50 views

### 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 ...
53 views

### CNC side linear rails

I've been wondering why most (hobby) CNC machines have two actuated linear rails like this: Besides the extra force for moving the spindle, is there a need for both rails to be actuated? Could the ...
218 views

### 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 ...
408 views

### 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 ...
39 views

### How can you convert 180 rotation into two separate motions?

I have a small servo that can rotate 180 degrees. I would like to get two different connected parts to move at different times, one part moving while the servo is between 0-90 degrees, the other part ...
99 views

### 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 $m$ ...
42 views

### Linear actuator with low vibration and low noise

Which kinds of linear actuators offer the lowest levels of noise and vibration? I am looking for an actuator with these properties that can push a load vertically on the cm scale. Velocity, accuracy ...
39 views

### Can I use more than 2 linear guides to support a linear stage?

I am designing a home CNC mill for machining nonferrous metals. I plan to use linear guides to support either a Y-axis table or the 2 legs of a Y-axis moving gantry. Linear guides are used to ...
25 views

### 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 ...
93 views

### What causes opposite motion in Newtons third law. Or is the mottion matter independent?

For every action, there is an equal and opposite reaction. Sample case me doing a push up I force myself to move up by pushing against a rigid body ( the floor ). There goes I can not push myself ...
179 views

### 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 ...
59 views

### 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) ...
392 views

### Stopping force on wire rope from a falling object attached to it

Okay, bit of a weird one. Imagine an object of known mass in free fall, tethered by a wire rope to an infinitely stiff sky hook. When that wire rope eventually tightens, what will be the stopping ...
83 views

### Is it possible to have the load cell signal as feedback to the servo drive of the servo motor?

In my project, I have to control the linear motion in one of the two modes. It will be either in position control or load control. for the displacement control, The servo motor takes the quadrature ...
29 views

### How to constrain stepper motor inside case?

I have a stepper motor linear actuator assembly like this for example, but the stepper shaft seems able to move axially back and forth - hence when I change direction it has to do a few rotations, ...
45 views

### Help with linear rod drill press like design/materials

I am putting together a basic machine for “pad printing” extremely small and precise parts. The design is very much the same as most homemade drill presses and consists of linear rods, flanged ...
134 views

### 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 ...
104 views

### How to debunk this "Perpetual Motion Machine?"

Here is video of a purported "perpetual motion machine." How do you explain its behavior?
85 views

### Ceiling Mounted Camera Slider with Pan

I am looking for feedback on my camera rig design. I am going to run a track along the ceiling of my studio to move my camera back in forth. I also want the camera to be able to pan, so I want to ...
27 views

### Using carbon brushes on linear guides

I’m designing a machine which has an actuator on a carriage sliding on two round linear guide shafts. I got an idea of transmitting electricity to the actuator through the shafts. There would be ...
354 views

### Rotary to linear motion - how to make upside down “hammer” mechanism?

I’m not an engineer, however I think this place is the best one to find an answer to my question. So my problem is as follows: I need to create a mechanism, preferably driven by a dc motor, that will ...
125 views

### Equations of motion for a motor supported by a spring resting at the centre of a beam

Assumptions from this: Sum of forces on the beam to be calculated Sum of moments on the beam to be calculated Sum of forces on the motor to be calculated As: F=-kx = kθL^2 Equations of Motion ...
162 views

### What lead screw to use for specific torque and speed requirements?

The setup: I'm trying to mount a leadscrew powered by this motor Tetrix Max Torquendado Motor on a 40ish pound robot, in order to lift it 4" off the ground. I already have the linear motion, latching ...
76 views

### Sharing load between linear actuators

I'm building a motorized standing desk and am trying to calculate what linear actuators I need. If I have 4 linear actuators (one on each corner) each able to lift 25kg does that mean that the desk ...
116 views

### 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 ...
49 views

### Linear actuator calculations

I'm building a motorized standing desk and am looking into what to use for the linear actuators. I'm targeting a stroke of 450mm and a lifting force of 100kg. I found some Linear Actuator on ebay that ...
124 views

### Shaft which can independently rotate and translate axially

I would like to mount a sensor onto a shaft which can be translated axially as well rotated independently. This arrangement permits me to capture a 360 deg scan and then translate the shaft axially to ...
4k views

### 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 ...
33 views

### Steering with a push / pull action. Is there an easier way?

Linked to my previous question Push / Pull Steering on an axle, I now have time and space to work on the full scale project. I have noticed an issue with the answer that is there, and that is, the ...
88 views

### Need to produce vibration amplitude of 200 um (approx) at natural (resonant) frequency, can be any frequency between 100 to 150 Hz

In order to conduct study, I need to produce controlled vibrations with amplitude (maximum) approx 200 um (micro) at frequency between (100-150) Hz. Vibration amplitude must be controlled with input ...
360 views

### Quick return mechanism for spring-loaded screw

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 ...
67 views

### Analytic expressions of the kinetic and potential energy [closed]

A homogeneous rigid circular disc (radius R, mass ms, center point S) rolls without a slip on a plain with a small angle of inclination alpha against the horizontal. A point mass MG is fixed on the ...
2k views

### Linear actuator on a scissor lifting table

I am designing a scissor lifting table and I have an issue with the linear actuator. This table should be lifting 100 kg. I studied the problem in two ways : a static study and a power study. My ...
45 views

### How can I calculate headphone driver excursion?

I'm a headphone enthusiast, and once I tried to open up my headphones to see how much they move when I play my music. However, I was really surprised to see that the sounds that I could "feel" ...
208 views

### Push / Pull Steering on an axle

I have a base with 4 wheels, the rear axle is a motor which drives the base forward or backwards, this contains a diff, so there's no problem there. The front axle is a steering axle like that in a ...
66 views

### What type of supports exists for ballscrews or leadscews?

For Linear actuators, a common mechanism is to use ballscrews with ballnuts. The ballscrew is supported at the two sides by a set of bearings which permit the rotation of the screw while keeping the ...
Im currently writing a model for a guidance law named Maintaining Guidance law. The law looks as following: $$a_{M} = [K_1,K_2]*[\dot{\lambda_T} ,\dot{\lambda_D}]'$$ Since im using a linear model I ...