Advice for the design of an automatic door opener

[cherrycoke]

Hello all,

I need to design an automated trap door opener incorporating a motor and at least one of the following: gears, springs, or power screws. It is 36 inches wide and 48 inches long. It is hinged along its width. The door weighs 60 pounds. When closed it is flush with the floor. It must rotate to 110 degrees when opened in 20 seconds.

I've calculated how much power I would need to rotate the door at the angle and time constraint, but I do not know how to execute the design. I was thinking of using a linear actuator but I'm not sure how to incorporate that with the wide opening angle of the door. Linear actuators I have seen used to open doors so far have opened too slowly and at most 90 degrees.

Any help would be appreciated, thank you !

 

[berkeman]

Hello all,

I need to design an automated trap door opener incorporating a motor and at least one of the following: gears, springs, or power screws. It is 36 inches wide and 48 inches long. It is hinged along its width. The door weighs 60 pounds. When closed it is flush with the floor. It must rotate to 110 degrees when opened in 20 seconds.

I've calculated how much power I would need to rotate the door at the angle and time constraint, but I do not know how to execute the design. I was thinking of using a linear actuator but I'm not sure how to incorporate that with the wide opening angle of the door. Linear actuators I have seen used to open doors so far have opened too slowly and at most 90 degrees.

Any help would be appreciated, thank you !

Welcome to the PF.

Can you post your initial sketches and calculations?

 

[bsheikho]

Maybe:
http://www.thingiverse.com/thing:134236

 

[cherrycoke]

Hello,

I hope the image attachment works. Here is my attempt at a kinematic approach first to find what HP motor I needed. Please let me know if I made wrong assumptions. Thank you!

 

[berkeman]

Maybe:
http://www.thingiverse.com/thing:134236

But that opens horizonatally, so the loading on the motor and opener are pretty light. He is asking about opening a trap door vertically, no?

 

[bsheikho]

But that opens horizonatally, so the loading on the motor and opener are pretty light. He is asking about opening a trap door vertically, no?

True, though I don't see how this concept can't be applied vertically with a stronger motor.

Its basically how all windows open, use rotary motion to swing open the windows.
That example is a bit more complicated with a rail and bushing,

 

[JBA]

Is there any foot traffic on or around the top area of the trap door when it is closed.

 

[malemdk]

Right angle gear motor is enough either worm gear box or helical type
You mentioned the size of the door as 36 in x 48 in but in your image it is in 'ft'