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Problem: Hoist
Ropes Bind in Rope Brake
When adding a rope brake, such as a
Hollister-Whitney
Rope
Gripper™, BODE Rope Brake or the Draka Sure
Stop™, to a traction elevator roped 1:1 there is often a
problem with the spread of the ropes coming from the
staggered car or counterweight hitch being too great for the
open jaw clearance of the rope brake. All car or
counterweight hitch plates have a staggered hole pattern
that allow sufficient space to fit and adjust the rope
shackles. The ropes lead off from the car or
counterweight hitch plate with as much as a 4-inch spread
with each rope running in its own straight line to where it
makes contact with the machine drive or the deflector
sheave.
Hollister-Whitney's
Rope
Gripper™, for example, has a total initial clearance
between the two open brake pads equal to the hoist rope
diameter plus 5/8". In a typical installation, the
hoist rope spread or lack of alignment will exceed the open
rope brake jaw clearance at around 18 to 24 inches below the
centerline of the sheave or about a 1/2 foot to a foot below
the sheave. If the rope brake is mounted below these
levels, the hoist ropes will cut too deeply into the rope
brake pads causing premature wear to both the ropes and the
brake pads.
Solution: Install a
Rope Align
Block™
The
solution is to add the
Rope Align Block™ as manufactured by
Smart Elevator
Tech, LLC. This device is easily installed above the hoist rope
shackles and below the rope brake to gather and align the
hoist ropes so they fit the rope brake jaw clearance.
Each Rope Align Block™ is made and labeled to
the specific hoist rope quantity, size and pitch (rope
center-to-center) to suit the elevator installation.
The hardwood blocks will not harm the hoist ropes and are
bored and countersunk with rope paths sized not to bind or
clamp the ropes, as required per code. In this way,
each hoist rope is free to move through the wood blocks as
needed for rope tensioning. Each assembly comes with
two 1/8" cables with two clamps each which thread through
the provided holes in the blocks and through the shackles.
These cables keep the blocks tethered to the shackles and
keep the blocks from riding up the ropes.
Order
To order,
simply call or email
Smart Elevator
Tech, LLC
and
identify
the quantity of
Rope Align Blocks™ needed for each hoist rope
quantity, rope size & rope pitch. Quantity discounts
apply and shipping is via UPS Ground or USPS Priority Mail.
Some Rope Align Blocks™ are in stock for
immediate shipment and if not stocked can usually be
fabricated and shipped within a week to 10 days from order
placement.
Installation
To install a Rope Align
Block™ it is essential to verify the available
clearance so as to properly locate the device between the
hoist rope shackles and the rope brake or other obstruction.
It is critically important to assure that the Rope
Align Block™ does not strike the rope brake or other
obstacle when the car or counterweight reaches their maximum
upward movement. See ASME A17.1 section 2.4.6 to
determine the "maximum upward movement" for the car and
section 2.4.9 for that of the counterweight. Also see
sections 2.4.9 and 2.4.11 which applies to the Rope
Align Block™ mounted above the counterweight or the
car not striking the rope brake, other equipment or
structure in the overhead.
To install a Rope Align
Block™ it may be necessary to reduce the tension on
the outer hoist ropes either by running out the nuts on the
outer shackles or running in the nuts on the inner shackles.
Install the split wood blocks of the Rope Align Block™
assembly at the location above the shackles as determined
above. Take care that the hoist ropes are completely
within the bored paths (holes) of both blocks and that the
blocks do not pinch the ropes. Tighten the two bolts
that pass through the wood blocks. Install the 1/8"
cables through the provided holes of the wood blocks and
through the shackles, snug the cables and add the cable
clamps. Re-tension the elevator hoist ropes as
required. It may be necessary to tap the wood blocks
lightly to release any internal binding that may exist
between the wood block as the hoist ropes, especially the
outer ropes. Finally, verify that all required
clearances are met.
Clarifications &
Disclaimers
Note that the Rope Align
Block™ does not work on a 2:1 or other multi-roping
scheme. The Rope Align Block™ can only
work on an elevator roped 1:1. Rope Align Block™
cannot be used as a hoist rope anti-rotation device (see
A17.1, 2.20.9.8). Rope Align Block™ may
not work on all applications as there may be insufficient
clearances to properly locate the device. It is the
sole responsibility of the purchaser to determine if the
Rope Align Block™ will fit and serve as designed
for each application. For installation on existing
elevator systems, a thorough field survey may be required to
determine the feasibility of properly installing the
Rope Align Block™. For installation on new
elevator systems, an analysis of the elevator and building
design drawings may be necessary to determine the necessary
clearances. Seek professional engineering services if
necessary (such services are available from
RCB Elevator Consulting, LLC). Installation of
the Rope Align Block™ must be performed by a
fully authorized and licensed (where applicable) elevator
mechanic/technician. Also reference the rope brake
manufacturer's installation instructions and appropriate
documents concerning the installation of the rope brake.
The purchaser assumes all responsibility and liability for
installation of the rope brake and the Rope
Align Block™.
Call
415-819-5744 or email
rich AT smartelevatortech DOT com
for pricing and delivery
Click to download a PDF Flyer of the
Rope
Align Block™
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Rope Align Block™