GSA Courthouse Management Group
Mechanical Lift Analysis
specification/general condition requirements as part of the construction documents for
bidding on each project.
Some of the issues that should be addressed at the time of installation include:
Lift platform support framing being out of balance,
resulting in excessive vibration and noise;
Misalignment of the platform, within the enclosure, causing rubbing
against the adjacent lift enclosure surfaces;
Jerking or slipping sensation requiring adjustments to the drive
mechanism; and
Proper sequencing of operation controls.
OPERATION
Interconnected Locking System Enclosure Gates
Interconnected electromagnetic locking systems are required by code. There are no
known alternative systems that ensure the occupant against a condition where the gate
could open between a lower floor level and an elevated platform condition.
Most of the problems with the electromagnetic system identified during this Analysis are
not due to a quality issue relative to the electronic strike device itself, but are due to the
method in which the electronic strike is typically incorporated into the circuits of the lift
system.
The failure and/or intermittent operation of the electronic strikes occur because in most
systems, strikes are continuously powered. This condition causes the armatures within
the strike to overheat whether the lift is in use or not. The fact that the armature is always
energized presumably causes the armature to "hang up" until the access panel or gate is
jiggled, thereby freeing up the armature and allowing the switch to function properly.
The solution to this problem is to energize the electronic strike mechanism only when the
lift is actually in operation. This can be accomplished by either (a) connecting the
"common" wire on the electronic strike through to the key switch, which activates the lift
prior to use, or (b) adding a switch to sense the position of the access panel or gate and
utilizing this switch to energize or de-energize the circuit powering the electronic strike,
based on whether the access panel or gate is open or closed.
This is a relatively simple modification to existing systems and specifications for future
projects. This approach should be investigated further to determine if, in fact, it would
provide a simple means of correcting the deficiencies noted at several of the existing
Section 3-9
HDR Architecture, Inc.
Previous Page
