Elevator door restrictor – Adams hatch latch

This will be the 1^st of a few posts on elevator door restrictors.  We get a lot of questions in our area about door restrictors when the restrictors begin failing.  Many in our area haven’t worked for years due to entrapments and have never been repaired. We get asked; Why did it fail? What is the next step?  We say “replace it with X,Y or Z”.  But many building owners have no idea what a door restrictor is or the differences between the different types.

What is a door restrictor? – A door restrictor is a device that restricts the elevator car door from opening more than 4” when it is outside the landing zone.  The landing zone is typically 18” above or below the floor.   Essentially this device traps someone in the car so they cannot get out of the car and fall below the car down the hoistway.  An elevator person or emergency services should be called to get a person out safely.

Why did the door restrictor come about? – I know there are people out there that can explain or tell this more accurately than myself, but, from what I know there was a series of accidents within a short period of time with people getting out of an elevator that was out of the landing zone and they fell down the hoistway and got seriously injured or died.  I believe a few of these accidents occurred in Chicago in the 1990’s.

In the mid 1990’s the City of Chicago mandated this device to be installed on all elevators and other AHJ's followed in later years.  

There will be 3 restrictors we discuss pros and cons for, the Adams hatch latch will be the first. Many elevators in the Chicago have Adam’s Hatch Latch door restrictors.  There are a few other companies who produce a similar door restrictor but in our area they are not as popular. 

The Adam's Hatch Latch is an electrical mechanical device that incorporates 2 sensors one for position of the elevator and one for the position on the door, a solenoid that picks and drops to allow the car door to open and close and a microprocessor board that operates the system.  There is a new version that operates a bit different with the 2nd sensor eliminated and replaced with a magnet.

[This particular door restrictor doesn't appear to capture the door position with the 2nd sensor]

Pros

1.    Easy to install 

2.    Will work with most elevator door systems – very flexible

Cons

1.    Many failure points – If any of these items fail it may cause an entrapment

a.    Battery failure - may not cause entrapment

b.    Board failure

c.    Solenoid failure

d.    Sensor failure

2.    Some versions are obsolete

3.    Requires on going maintenance

Purpose of this information - We frequently see on elevator violations “Repair door restrictor” or we see entrapments due to malfunctioning door restrictors.   If a building has a door restrictor from the 1990’s, 2000’s there may be a better replacement such as a door clutch mechanical restrictor or a SEES style door restrictor or replace with a newer version of the Adam’s Hatch Latch.

As always feel free to contact us at www.colleyelevator.com, email Craigz@colleyelevator.com or call 630-766-7230.