need a reciprocating mechanism

[engineheat]

Hi,

I wonder if there are kits or toys that offers a reciprocating mechanism that converts rotary movement into linear? I need the linear movement to be about 1 - 2 cm, and the mechanism should be as small as possible. I wonder if there are kits or toys that you know of that have such a mechanism?



Thanks

[sandalcandal]

Lego?
Kinda cheating considering you can build pretty much any basic mechanism but should work as long as you don't need too much load bearing
http://www.technicopedia.com/fundamentals.html

Attach a stub axel to one of the off-centre holes in a gear then you can make a crank like that.

Edit: This has some examples https://www.daslhub.org/unlv/courses/me425-625/lesson-B-simpleMachines1-leversShaftsAndCranks/lab/labLegoLeversShaftsAndCranks.pdf

[andy3055]

With an old style mecano set (those metal stuff) you could make one easily. All you need is a circular piece with holes, a straight piece with holes, a tiny motor and a couple of nuts/bolts.

[SeanB]

I know of one, though the mechanism is rather dodgy, along with the suppliers. They are common in toys, so look in the toy store for some with this motion.

You have not mentioned volume, expected lifetime, number of cycles per minute, or voltage and current available for it.

[ledtester]

I found some toys searching for "Tamiya" and reciprocating, such as:

https://www.hobbylinc.com/htm/tam/tam71101.htm

as well as the other Tamiya kits on that site.

They're not going to be cheap.

[jpanhalt]

Since you don't give any power requirements...

Linear converters for model servos have been around for decades.  There are also "linear servos" today.  Check Google or Amazon.

[james_s]

Is this for a one-off? All you need is a wheel or arm you can attach to a shaft and then drill a hole and attach an arm. You haven't really given enough information for anyone to make a specific recommendation.

[Raj]

The smallest linear motion actuator I've ever seen are usually in camera lenses. A motor rotates a screw, which pushes on a nut. The nut can't rotate so it has to go up or down.
There's also this-https://youtu.be/_UySbXafPyM
Adafruit sells something similar.
But do you know pcb way, I think, sells 3d printed parts now?

[NiHaoMike]

You didn't specify roughly how many turns for full travel, so if it's many, a screw and nut will do the trick. Grease them before assembly to reduce wear.

[DrG]

Alibay has a load of micro steppers like this:

search for "micro steppers"

and here is an interesting toy mechanism:
Search for "Reciprocating motion model Maker DIY electric motor drive toy crank linear motion model"

When are you going to tell us what you are up to?

[RJSV]

   I have a couple of greeting cards, specials with minor electronics, for Halloween 'monster cards', having blinking LED eyes in the special greeting card.
Now, also the unit has a reciprocating mechanism, for producing 'eyeball' wiggles.
  The little mechanical box contains 10mm X 3mm motor, and a couple gears. I'm not sure if the little controller IC sends both directions polarity to the motor (IC is inside epoxy dot).
The little gear box is 20mm by 20mm by 8mm thick.
   You'd have to check Hallmark Cards, and I will keep a look out, for that special Halloween card.

[beanflying]

While the OP hasn't been back with some required info the little indoor R/C linear servos are about the easiest to incorporate into a design with minimal mechanical engineering or hacks needed. Costs on them are sub $10USD and all you need to drive them is a 4-6VDC supply and a 1-2mS pulse from anything from a 555 timer hack to a PWM out of an arduino. Some of the other screw options from AliX or evilbay are a bit more robust but you would need to do the drive electronics and position sensing too if you need accurate control.