Simple continuous back-and-forth linear movement

[bimusicmaker]

I need to purchase a device that will push something forward and backward continuously, in order to make wings flap like a bird. Linear actuators seem to be the right thing to buy, except these require pressing buttons to go forward and then back. What can I buy/what can I do that will allow a linear actuator (or something similar) to continuously move back-and-forth?

I much rather buy something that already does this than to build a machine or program anything.

 

[OldEngr63]

Why not use a simple slider-crank mechanism? This will convert continuous rotation into a reciprocating motion. Sounds to me like what you want.

 

[bimusicmaker]

I agree, however I do not have the resources to make one myself. Do you know of anything I can buy that will accomplish this?

 

[OldEngr63]

You don't say anything about the stroke, frequency , force, et, required, so no, I don't know where you can buy an undefined mechanism.

 

[bimusicmaker]

The stroke would ideally be around a foot long, frequency would ideally be around 16 rev/min. Force no more than 30 lbs.

Another option I was considering would be to use a linear actuator connected to some sort of device that will reverse polarity every 4 seconds or so in order to achieve this reciprocating motion. I am pretty unexperienced with this sort of thing so any advice would be appreciated.