Having Trouble Finding A Linear Actuator!!

[Eventorizon]

Does anyone know where to get an actuator like this in the UK that doesn't cost a fortune...

http://www.runyn.com/100mm-4-inch-strok ... ml?cPath=1

Everything thats in the UK costs around £100 + but this is about £35 ex shipping.

Any Ideas?

[mattsdragons]

Re: Having Trouble Finding A Linear Actuator!!

i would take that, its a good price and very high powered

[Ellis]

Re: Having Trouble Finding A Linear Actuator!!

Today I stuck a standard 10mm screw thread into a slightly discharged 12v cordless drill, with a nut on the thread, turned it on and I pushed down on the nut with all of my force. It didn't even slow down one bit. I later measured how much force I was pushing down with, and it was 30kg (I'm 15, don't laugh!).

A drill and screw thread, say a 12v motor at 18v, standard m10 bolt and nut, you will have something that could compete with a commercially bought actuator, for next to nothing. If it was a 12v drill at nominal voltage and it didn't even slow down for 30kgs, I reckon it could quite comfortably lift in the order of 100kg at 18v.

Fraction of the price, rather more powerful. Just something to think about.

[widow_twanky]

Re: Having Trouble Finding A Linear Actuator!!

Today I stuck a standard 10mm screw thread into a slightly discharged 12v cordless drill, with a nut on the thread, turned it on and I pushed down on the nut with all of my force. It didn't even slow down one bit. I later measured how much force I was pushing down with, and it was 30kg (I'm 15, don't laugh!).

A drill and screw thread, say a 12v motor at 18v, standard m10 bolt and nut, you will have something that could compete with a commercially bought actuator, for next to nothing. If it was a 12v drill at nominal voltage and it didn't even slow down for 30kgs, I reckon it could quite comfortably lift in the order of 100kg at 18v.

Fraction of the price, rather more powerful. Just something to think about.

You are probably better off using something a bit more robust and also from experience with Cylon when it had this type of actuator from a Bosch 35W the bearings at each end need to be good because the play is a real issue in terms of reliability.

That said when you buy a rover seat for the Bosch 35W motors you gets an abundance of really useful tried and tested linear actuators.

Andy

[gizz]

Re: Having Trouble Finding A Linear Actuator!!

You can use a mechanical car jack with a threaded rod and the nut that comes with it, doesn't cost much either

[shakesc]

Re: Having Trouble Finding A Linear Actuator!!

I've been looking around for linear actuators and that is a very good price if it meets the advertised specs
Everything else I have found is around £100

[Eventorizon]

Re: Having Trouble Finding A Linear Actuator!!

Unfortuately there are no dimensions so I have no idea whether it will fit inside the robot. I could widen it but that makes it heavier, less rigid etc I might use the threaded rod idea but finding one with a chunky enough thread might be hard.

[Ellis]

Re: Having Trouble Finding A Linear Actuator!!

A standard M10 bolt and nut will have ample strength. It may wear since I guess they are rather soft material, but you could comfortably hang from screw threads. Shouldn't be an issue, or at least it won't be for quite some time. Remember also that higher pitch screw threads may be tougher and they will have greater speed but less lifting power (less torque). Also, is less bigger threads better than more smaller threads?

[RogueTwoRobots]

Re: Having Trouble Finding A Linear Actuator!!

Also, is less bigger threads better than more smaller threads?

Depends entirely on the application, but for use as an electric lifter in a robot, I'd say the bigger threads are better. What you will find with more smaller threads is that because there is a large force pushing the nut down the thread (if you're lifting a robot), there is a possibility that the nut/threads will bind. This can be as a result of the pressure deforming the threads due to them being thinner and weaker, and then jamming up.

By opting for a rod with a chunkier thread, you reduce the chances of this happening. Yes you lose torque compared to finer threads but the threaded rod actuator combo usually has enough power that the loss in torque will have little effect on the robot's ability to lift (although again that depends on the application and what motor is being used to turn the rod).

Three main sources of chunkier threaded rods that aren't custom solutions are car scissor jacks, G-clamps, and part of the rotating handle mechanism from your typical hobby workbench. The scissor jack is probably the most useful as you can use the 'nut' out of the jack too, whereas with the clamps you might have to try and locate a nut with the correct thread pitch or butcher some other part of the tool to try and create a mechanism. They can also usually be picked up from a car breaker's yard for around £5.

[Eventorizon]

Re: Having Trouble Finding A Linear Actuator!!

I am going to use it to power my self righting mechanism but in the future I may want it to lift other robots to, but Its primarily a shrimech!