clues on designing an automated gate

[raysheild]

i'm working on a personal project which has been in my head before i gain addmission in to the college and now i want to start working on it.

the mechanical transmission system to my project is two parrallel square threaded shaft connected together by a sproket and chain,and the system will be prime by a 3phase electric motor which will transmit the torque to the upper shaft.

the clues needed are as follow:

* The best material for the shaft because i considered mild steel to be the best.

* the best threading for system because i'm considering acme and square threading.

* and lastly the one that really gives me problem is the connection of the primer i.e (elecric motor),because i want it to work in such a way that when the gate opens fully and the motor feel the resistance force of the spring,it would stop for a preset period of time and rotates in the other direction for the shaft to move in the other direction.

 

[quark]

Generally Rack And Pinion system is used for sliding gates. Why you want to go for chain sprocket type? I didn't get your idea of threaded shafts. For general application EN8(AISI 1040) or EN9(AISI 1055) material is used for shafts.

You can use door limit switches to sense the gate position and stop the motor. Timers can be used to delay the motor starting.You can fix two door limit switches at two ends of the door and the signal from these limit switches can be used to stop the gate and for selection of direction.


Motorised Gearbox and Rack (standard length is 1feet) are standard items for door automation.

 

[peglor]

Another factor to consider is what happens if the power supply to the gate is cut off. Do you want the gate to default to an open or closed position or remain wherever it was before power was cut off.

I'd recommend a rack and pinion to drive the gate too. There's much less to go wrong and maintain compared to a chain drive.

 

[arto]

Don't forget some kind of safety switch/sensor to prevent squishing the neighbor's cat or getting your foot stuck when carrying in the groceries ;-)

 

[TheAnswerGuy]

raysheild,

I would suggest that you go take a look at the "GENIE" Garage Door Opener system. This system utilizes the turning drive screw method for moving the garage door up and down. I believe that they also sell a system that can be used on swinging gates. You will probably find valuable information there to incorporate into your design.

 

[nbucska]

You may search the Patent Office : <

http://www.uspto.gov>

<nbucska@pcperipherals.com>

 

[raysheild]

I QUITELY APPRECIATE your contribution guys and i think i would surrender to the use of the rack and pinion considering the cost of machining.

but the way i was thinking of design it goes thus:

the threaded shaft will be stationary rotating on it's circumferential axis and it will be incorporated into a split nut in which half side of the nut will be welded on the back side of the gate. so that while the shafts are rotating on their circumferencial axis,the nut will be moving along the lead and consequentely carring the gate along.but the shafts will be spring loaded at the end to prevent the gate from abrupt jamming and preventing power surge in the motor.

and the split nuts will be 4 in number i.e two at each end of each shaft.

and i think it will be more safe to let the gate to remain at where it was before power cut off,so that in case may b ea car or whatever was comming in it will still have it's way and will be prevented from jamming the car.before i will wind the gate mannually or start a generator.