Need to slide an arm under a bed

[Just Whisper]

I am building a prop which is an arm that comes out from under a bed. I am using a reindeer motor (see pic) and a life size arm. The problem I am having to figure out is this...I want the arm to sit pretty much flat on the floor and slide forward and back, about 6-8 inches. But if the motor is close to the floor I don't have enough clearance for the shaft that would make the arm move the 6-8". And if I raise it off the floor I am afraid it will jam it's fingers into the ground from being at an angle and mess up. Does anyone have any great suggestions on how I can get around this? It seems like it should be simple enough. Thanks.

http://i245.photobucket.com/albums/gg54/Just_Whisper/2010/Halloween%20Props%20in%20Progress/Monster%20under%20the%20bed/arm.jpg

[The-Haunter]

How about caster wheels?

[Otaku]

A low-profile drawer slide might work. Can you mount the motor above the arm/linkage? The bracket would need to have ~8" of clearance to give you the length of travel that you want.

[corey872]

Could you just mount the motor with the shaft vertical. The crankshaft would rotate in a horizontal direction and you would still have the push rod going in and out. I suspect under the bed, space to the side shouldn't be an issue and you should be able to make the rig and pushrod deep enough to support the arm a fraction of an inch off the ground so hang-ups wouldn't be an issue.

If the description isn't clear, I can probably sketch it out.

[MonkeyBasic]

What if you mount the motor so the shaft is vertical (pointing down). Then you wouldn't have to worry about ground clearance, but you would have to deal with side to side motion and keeping the arm straight... hmm.

[MonkeyBasic]

Haha, Corey and I are apparently thinking alike. :)

[Just Whisper]

See, I knew I wasn't thinking clearly. I was so tired, and soooo HOT from being outside. I knew I was missing the blatantly obvious. Thank you everyone for your suggestions. Corey and Monkey...that is what I was looking for. And I may also use the suggestions for a slider. Thanks again everyone. Problem solved. Probably. LOL

[Doc Doom]

Here;s a VERY rough schematic of how you could set up the motor to have tghe shaft point down and hav e the arm slide on the floor.

[corey872]

Yep, that is pretty much it. I was thinking of adding another 'green thing' and a connecting rod to the crank. That would give two points of support and you could hold the arm just a fraction of an inch off the ground. Of course, that would only give you a 'straight out, straight in' motion. You should have enough torque to use only one green thing and run exactly as drawn... that would give a weird in-out,side-side squiggle motion with the crankshaft.

(I hear 'ya on the heat... hit a heat index of 115º here today. It feels a bit.....um...."toasty". Even more strange to think a few Halloweens we've had snow...so 100º+ down to 32º or less in 79 days!)

[debbie5]

Just pay a 5 year old 10 bucks to be under the bed..problem solved.

Or duct tape him there....

[RoxyBlue]

JW, if you rig it so the motion can be reversed, you can use it to sweep the dust bunnies out from under the bed in the off season:D

[Just Whisper]

Yeah!!! Debbie and Roxy's ideas win!

All done. Here is a video, if I can get it to work. thanks for all the help.

Monster under the bed :: Monster Under the Bed Prop video by Just_Whisper - Photobucket