6 votes
Accepted

Off-centre actuation

Does anyone know if this would be a good idea? The proposed design has poor rigidity towards torsional loads. It doesn't matter whether the actuator is off-center or if the load is off-center: if ...
jpa's user avatar
  • 1,943
6 votes

Off-centre actuation

Your mechanism is going to lock up like the old car jacks immediately, due to differential raising of the platform. I am sorry but it looks like a textbook example of what not to do. in most real-life ...
kamran's user avatar
  • 22.2k
5 votes
Accepted

Lifting a cabinet using actuators or scissor lift

In a scissors jack design, items one and three, you'll have the least mechanical advantage when the assembly is retracted. Using drawer slides or the equivalent is a good idea, but will not provide ...
fred_dot_u's user avatar
  • 7,055
4 votes
Accepted

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

Screw: M6 M6 coarse has a 1 mm pitch. M6 fine has a 0.75 mm pitch. Unless otherwise stated assume coarse, so 1 mm pitch. Your motor is 1.8° per step. This is 360/1.8 = 200 steps/rev. The screw will ...
Transistor's user avatar
  • 10.6k
3 votes

How to debunk this "Perpetual Motion Machine?"

Looking at the demo video, this machine looks fake to me. The person who assembled and exhibited it in the video used some trick to move the machine. I believe there is a platform that can tilt and ...
Mohit Jain's user avatar
3 votes
Accepted

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

A pneumatic cylinder is linear by definition The form factor for a cylinder defines this. You can turn this linear motion to rotary via a crankshaft or rack & pinion, to give two examples. You ...
Tiger Guy's user avatar
  • 6,813
3 votes

Linear actuator that extends more than its retracted size

already found an answer :facepalm:. It seens that telescopic linear actuator exists and have two screw inside of another. Here is a demonstration: https://www.youtube.com/watch?v=CYz1gQG_ijs&...
Italo Guedes's user avatar
2 votes
Accepted

Sharing load between linear actuators

Yes, the four will share the 100kg, each carrying 25kg. Only thing is you want to connect them to same rocker switch and install the linear actuators symmetrically with respect to the center of your ...
kamran's user avatar
  • 22.2k
2 votes

Converting Linear Motion into rotary motion

This is a diagram for the mechanism, . And here is Wikipedia link, click.
kamran's user avatar
  • 22.2k
2 votes
Accepted

How to constrain stepper motor inside case?

Constrain the driven shaft and use a coupling to the motor.
Solar Mike's user avatar
  • 15.6k
2 votes
Accepted

Help with linear rod drill press like design/materials

it may be necessary to construct more than one design (known as iteration) in order to refine your final objective. "Very rigid and with no slop" is a rather general description. "A tolerance of 0.10 ...
fred_dot_u's user avatar
  • 7,055
2 votes

Design Input: Rotary motion to Linear motion, What system should I choose?

Obviously cranks and pistons have been used for hundreds of years for this. Your other option would be fast-acting motors or hydraulic rams. But a 500N (or is it 600?) force isn't what happens when ...
Tiger Guy's user avatar
  • 6,813
2 votes
Accepted

Linear actuator behind lifting boom

Initial thoughts? I'm not a mechanical engineer but I think you'd be disappointed. Figure 1. A quick pictorial analysis shows that there is almost no reason for the lift arm to move up. Also, most ...
Transistor's user avatar
  • 10.6k
2 votes
Accepted

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

The idea is mostly sound. I have a load F that is too high for my linear rails....so instead of beefing up my rails, I increase the load sharing across 3 or more rails, thus dividing it. In reality,...
DrMrstheMonarch's user avatar
2 votes

Off-centre actuation

IMHO (and I guess you already know that), from a structural point of view putting 100 kg at 1/4[m] will create a huge amount of bending moment on a actuator that it is rated for 120[kg]. An although ...
NMech's user avatar
  • 24.3k
2 votes

Lifting a cabinet using actuators or scissor lift

Either one would probably work as long as you gear it properly; but like Eric Shain, I'd advise you to go with the scissor jack because it's simpler. However, because the force varies with the angle ...
Palbitt's user avatar
  • 239
2 votes

Difference between Linear Force and Force about an Axis

Take a look at the illustration below, which is how I understand your question. You're asking, what would be the minimum value for the blue arrows in order to make each object move? First, let's look ...
Jonathan R Swift's user avatar
2 votes
Accepted

Single linear actuator lifting mechanism

As a quick basic estimation approach we annotate the following: The length of bar 3 = L Top and bottom bearing force on each box $F_b$ The height and width of boxes 4 and its counterpart on channel ...
kamran's user avatar
  • 22.2k
2 votes

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

Figure 1. A Kinetrol rotary actuator. This type of rotary actuator is also known as a vane type. This one has a 90° action and is popular for controlling ball or butterfly valves. Figure 2. A rack ...
Transistor's user avatar
  • 10.6k
2 votes
Accepted

Linear solenoid mount

Figure 1. An image search for "M3 clevis male" throws up a wheelbarrow-full of images. You could use a female thread version but would need to connect the them with a male stud and maybe ...
Transistor's user avatar
  • 10.6k
2 votes
Accepted

Ideas for mechanism for quick reciprocating motion - a 'truly' mechanical switch

One of option might be the following figure source with video You can adjust the contours of the cam to create a more square profile. square velocity profile The following mechanism also has a ...
NMech's user avatar
  • 24.3k
2 votes

Is there such a thing as a double roller/bearing? Two rollers/bearings that share one axis, but can roll independently. [linear/pivot]

You can simply google the word "drawer wheels" to get results that fit your need. The one shown has an OD of 1 1/8".
r13's user avatar
  • 8,184
2 votes

How do linear guides work?

Are the carriages able to move on the bar if you put them on there? The slider(carriage) moves along the rail (bar) in 1 axis. And is there a way to keep them fixed in one position? No, common ...
Drew's user avatar
  • 1,921
2 votes

Simple mechanism to convert linear motion into 180 degrees rotation

Without any furter information, the Scotch Yoke is probably what you are after
NMech's user avatar
  • 24.3k
2 votes

Driving an air cylinder with ignited hydrogen/oxygen gas mixture from fuel cell?

I asked our chemical engineer at work about this and she was able to source a NASA research project that tested and achieved almost exactly what I'm trying to do. They built an electrolysis generated ...
dutenh's user avatar
  • 31
1 vote

CNC side linear rails

What happens in the arrangement is that you are applying a force away from the center of gravity. Imagine you have a pencil on a flat surface and you try to push. If you don't push it around the ...
NMech's user avatar
  • 24.3k
1 vote

Linear actuator with low vibration and low noise

I might look into medical equipment, I was looking at actuators the other day, and they weren't too expensive.
Ryan Griffith's user avatar
1 vote

What causes opposite motion in Newton's third law, or is the motion matter independent?

A potentially helpful visual is imagine sitting in a very flat rowboat on a placid lake. Now throw a javelin far away from you. The javelin will fly in one direction, and you and the boat will start ...
RC_23's user avatar
  • 831
1 vote

What causes opposite motion in Newton's third law, or is the motion matter independent?

This is one of Newton's Axioms. I.e., strictly speaking the rule does not need to be able to be derived from some other physical law, but an empirical fact supported by a huge number of actual and ...
HelpingHand's user avatar
1 vote

What causes opposite motion in Newton's third law, or is the motion matter independent?

Rather than think of it as 'resisting', think of it as force. In a vacuum, you are correct that there is nothing to push against, nothing resisting. The resisting, as you put it, comes from pushing ...
Ack's user avatar
  • 358

Only top scored, non community-wiki answers of a minimum length are eligible