# Automatic Stop for Dumb Waiter?



## guest (Feb 21, 2009)

swimmer said:


> There is a 8" square galvanized box with electrical connections below the motor / belt / jackscrew assembly. _*This box contains electrical connections and a 4" diameter plastic gear. However, this gear does not contact the jack screw. I suspect that this box is related with the automatic off function but I don't know how. *_Very tight in the shaft and difficult to work and inspect.


This is the limit switch assembly. The gear should (MUST) contact the jackscrew shaft and there will be switches in that 8" square box, one for the upper limit and the other for the lower limit. 

In the cinema biz, curtain and masking motors use the same kind of setup. 

That said, I caution you against trying to fix and re-adjust this yourself. It will be VERY easy to create major mechanical damage or hurt or kill yourself if you aren't 100% sure of what you are doing. (And if any of the smartasses come on here about being overly dramatic, they can blow me.) This is a serious thing. I have had the misfortune of tearing down a complete curtain track when I attempted to adjust a curtain motor and over-ran the mechanical limits. Damage was over $7,000.00. Luckily I didn't hurt or kill anyone. 

You should tell your customer that they need to call in a specialist on elevators/lifts/dumbwaiters to get that fixed. (Or if you know of the local Thyessen/Krup, Otis or Schindler service reps in your area give them a referral.)


----------



## swimmer (Mar 19, 2011)

I can't find any local elevator repair in Google. I'm going to contact a nearby condo association and ask who they use for their elevators. I was able to contact Thyessen/Krup but their scale of operation is exponentially larger than what I'm dealing with.

Anyway I found the following: The motor stops with a second activation of the key switch so there is a way to stop the motor when the car is between me and the toggle switch under the motor housing.

The plastic gear in the 8" box does indeed contact the jackscrew through a slot in the 8" box. Since the jack screw will not rotate, I have not been able to see the limit switches in action but all other electrical is working.

Aside from unknown condition of limit switches, the sole problem is mechanical. 

Due to the constrained space in the shaft, my glasses fogging, and the position of the car in front of the jackscrew, the only thing I can possibly do is to tighten the nut that holds the belted wheel to the jack screw. Any other action, on my part, would require tearing up the wall to access this stuff.

I'm unable read the horsepower rating on the motor but judging from the size I'd say less than 3hp. 

I could only see the above mentioned nut with a mirror so I don't have a picture. Do you know its purpose? There is a spring between this nut and the belted wheel.

A picture is attached


----------



## BBQ (Nov 16, 2010)

mxslick said:


> I have had the misfortune of tearing down a complete curtain track when I attempted to adjust a curtain motor and over-ran the mechanical limits. Damage was over $7,000.00. Luckily I didn't hurt or kill anyone.


Dude, I never want to be around you, bad luck follows you. If it is weird or dramatic it has happened to you. 


By the way I do agree this has the potential for injury


----------



## BBQ (Nov 16, 2010)

swimmer said:


> I could only see the above mentioned nut with a mirror so I don't have a picture. Do you know its purpose? There is a spring between this nut and the belted wheel.
> 
> A picture is attached



Not to sound like a drama queen myself :jester: none the less I would recommend you walk away from this job or you cut an access hatch into the wall. That is a jack ass set up and the only way to check your work on the limit switch is to run the car. How are you going to run the car, watch the car and be ready to kill the power if it over travels from your point of view.

This really should have an access for the motor and controls.


----------



## erics37 (May 7, 2009)

My kid is how I get groceries inside from the car.


----------



## s.kelly (Mar 20, 2009)

Try accesibilty, or stairlift companies. I used to do some of this work, occasionally did a dumbwaiter, often elevators, and often other types of lifts.

Has got to be someone in the area that does this. BBQ is right, I think this is probably a fly by night set up, few things just do not look right with that install, though it has been some a while


----------



## kevink1955 (Apr 25, 2012)

I would stay away from that one, it looks like a modifyed commercial garage door operator right down to the terminal strip. If you have ever seen a real elevator/dumbwater no way would it have any exposed terminals.

Run fast


----------

