JW

Joe Willmann

08/01/2004 6:20 PM

Need help finding hardware

I built some bookcases into a sliding wall. It hides a "secret room". The
book cases hang from barn door hardware and are guided by a short track on
the floor. With the wall/door closed you can not tell there is a room
behind there. The problem is when you fill the book shelves with books
they get heavy. I want to motorize the door. So I am looking for possible
hardware.

I have thought about using a screw type garage door opener. The concern
with this aproach is the range of door movement. I need about 5 ft ove
movement. Can the standard door openers be adjusted for that small amount
of movement?

Does anyone know of any sources for this kind of hardware?


This topic has 2 replies

mm

"mel"

in reply to Joe Willmann on 08/01/2004 6:20 PM

08/01/2004 6:37 PM

door openers have a trip switch that mounts to the track that limits the
range of movement.

bR

[email protected] (Robert Bonomi)

in reply to Joe Willmann on 08/01/2004 6:20 PM

08/01/2004 7:29 PM

In article <[email protected]>,
Joe Willmann <[email protected]> wrote:
>I built some bookcases into a sliding wall. It hides a "secret room". The
>book cases hang from barn door hardware and are guided by a short track on
>the floor. With the wall/door closed you can not tell there is a room
>behind there. The problem is when you fill the book shelves with books
>they get heavy. I want to motorize the door. So I am looking for possible
>hardware.
>
>I have thought about using a screw type garage door opener. The concern
>with this aproach is the range of door movement. I need about 5 ft ove
>movement. Can the standard door openers be adjusted for that small amount
>of movement?
>
>Does anyone know of any sources for this kind of hardware?

This is a relatively trivial "build it yourself" job.


I just built an 'opener' assembly, from scratch. components, and
approximate pricing:

6' 3/4" threaded rod this is the screw drive $10.00
"long" (roughly 2") hex nut the 'follower' $ 0.75
2 pillow-block ball bearing supports 10.00/ea
2" dia drive gear (3/8" 5tpi cog-belt drive) 17.00
1/10 hp, 1500rpm, _reversable_ motor *surplus* 9.95
w/ 3/8" 5tpi drive gear
3/8" 5tpi cog belt 5.00
low-voltage control system 20.00
metal hobby enclosure
12V transformer
rectifier (couldn't find AC relays, use this w/ DC relays)
2 relays (one for run/stop, one for open/close)
two 'limit switches'
3-way switch
power cord

misc hardware 3.00

Total cost, about $85.

I could have saved $25 or so, If I'd felt up to fabricating my own
supports for surplus ball-bearing races, rather than buying new industrial-
grade, and v-belt instead of cog-belt drive.

And likely another $5-10 on the 'electronics', by shopping discount/surplus
sources, vs just bying all at Radio Shack. But they _were_ conventient. :)


This opens/closes a 4-1/2' spam in about 30 seconds.


For your application, I'd gear down further, or use a more powerful
motor. 1/4hp might run $20, and 3/4 hp ones (from treadmills) were
going for around $40, at the same source I got my 1/10 HP one from.


Note: for those into 'gadgeteering', and not familier with the place,
"American Science and Surplus", online at <http://www.sciplus.com>, is
a *dangerous* place. Ditto for "Surplus Sales of Omaha", online at
<http://www/surplussales.com>








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