Linear Actuator 50mm~75mm Displacement

"Damper motors" might be a good category to search. What sort of torque or force do you need?

May be around 200~500 gram force.

A 1lb club hammer, perhaps?

It's called a solenoid; two states, on/off, fully extended/retracted.

Off the top of my head, I don't recall any with that long a stroke, but my areas of experience never required it. That would be the ticket, though.

Yes, I searched ebay and RS components, I found none 50~75mm displacement. The usual maximum displacement is only at 25mm

I think I gonna have to sort it out with an angular link to get 50~75 linear displacement but, anyhow, thank you RAM & Tornado for the help. I appreciate it.

Use 2 in tandem?

As a side note, a tandem actuator would cater to a 0-50-100% 3-position control.

A bonus!

I've actually seen that done, but I can't remember where. Worth mentioning, though.

You may find the solenoids that trigger those flipper mechanisms used in pinball machines useful?

Some other possible ideas:

https://www.google.com/search?q=long+stroke+linear+solenoids&ie=utf-8&oe=utf-8

For such strokes and forces I would suggest a moving coil actuator (type loud speaker) and a long magnet. Forces being low even ferite magnets could be OK. By polarity change the coil mouves from one end to the other. This could be the simplest solution. The magnet is in the coil and due to its variable field interacts with the coil field which tries to find the position where the interaction is the strongest.

You could also use a mechanical stroke amplifier since short stroke electromagnets have rather high forces. You should use 2 in opposite since they act ONLY in one direction. If you use only one the return must be made by a spring which increases the force requirement. There are also double acting magnets with 2 coils since active in both directions.

This might work as a concept....can anybody explain how this works?

https://www.youtube.com/watch?v=TKgRCIarczo

Another approach may be a linear piezoelectric motor setup....

https://www.youtube.com/watch?v=uFZsH62ewYo

Nice SE

Thank you it is exactly what I suggested. I could not find a better support!

Here's a source...

http://www.dynamicsolutionsusa.com/product/mechanical-components/moving-coil-actuators

http://www.dynamicsolutionsusa.com/docs/moving_coil_actuators/ca-catalog.pdf

Demo...

https://www.youtube.com/watch?v=TIAtV84g-xU

A even better solution is the one of h2w technologies which inverted the design so that the coil is fixed and the PM moves. This has the advantage that the supply for the coil will not fatigue. info@h2wtech.com is their e-mail address.

http://www.physikinstrumente.com/technology/piline-ultrasonic-motors.html

http://www.piezo-motor.net/pdf/PI_Brochure_Piezomotor_Piezo_Motor_PiezoWalk_Ultrasonic_Actuator.pdf

Maybe i am missing something here, but won't something like LINAK do the job?

http://www.linak.com/

My thoughts exactly. Good range and built in limit switches.

Jim

Why has no one mentioned an air cylinder? Really easy! can be controlled by an air toggle or an electric solenoid or...

75mm is pretty far for a magnetic solenoid, unless the core is a permanent magnet.

A motor (/gearbox) with a crankpin driving via connecting rod to the load should be first choice. The motor need not reverse so cheaper than screw systems. The holding forces are radial so very robust and the motor's start and stop torques are minimised.

Position sensors can be cam driven leaf or microswitches, optical or magnetic, Hall probes or reed switches: selected to fit your control needs.

Try http://www.firgelli.com/category_s/1823.htm

I use them to make electric shifters. Lotsa options, and the people there are very helpful.

Dear Peterpipper, how fast is 'fast' ? 100 microseconds? 10 seconds?

My crank and conrod suggestion was used in the 1940's by a colleague, I used it from time to time through to the 1990's. Its benefits are:-

Slow acceleration, fast major travel, slow retardation.

Tolerance of stopping point. +/- 10 degrees usually acceptable.

High forces acceptable, with tiny load on the gears.

No power consumption in either stable position.

If the length is inconvenient the crankpin can drive the load by a slotted member at right angles to the load's motion. A bearing bush or race on the pin may be worthwhile.

Don't know what your constraints are, but maybe a bell crank might assist in your throw/ leverage?

Any pneumatic cylinder would give you linear motion. Attached to linear rail and carriage would give precise motion. There are also Air Slides. Check the manufactures of air cylinders.

And if he has not compressed air ?

The advantage of an electro-mechanic solution is the fact that electricity is every where available.

If forces are low the complexity of a "transmission" is not the best choice. The moving coil or the moving PM are the most economical solutions since maintenance is almost nil.

A solution is optimal only if the total cost of ownership is considered not only the solution technique and its price.