R&M Materials Handling, Inc
STAGEMAKER
®
Concert Hoist
Springfield, Ohio USA
Technical Guide
:
800 955-9967
June 2009
www.rmhoist.com
RM-STGMKR-TG-2002-6-ENG.doc
43
®
9 Hoist Brake and Torque Limiting Device
The friction materials for the brake and the torque-limiting device are asbestos free.
The hoist motor is equipped with a D.C. electromagnetic disc brake to bring the load to a smooth and
quick stop and to hold the load when the hoist motor is not energized. Multiple springs are used to
provide the clamping force. An energized coil releases the hoist brake.
The motor brake on SM1, SM2, SM5, and SM10 is located in a sealed housing to provide a degree of
protection against dirt or water penetration. The components are designed to dissipate the heat. On the
other hand, the hoist brake on SM16, SM20 and SM25 hoists is located in a vented housing and a fan
provides additional cooling.
A built-in torque-limiting device prevents the lifting of excessive loads, which could damage the hoist
and/or the supporting structural members.
The torque-limiting device is set to slip at 125% of rated capacity, except configuration D hoists. The
capacity in configuration D is de-rated 50% from standard to meet BGV-C1 regulations in which require a
mechanical design factor of 10 to 1 minimum for the hoist. This includes the clutch, which is set at 250%
of the de-rated capacity.
The torque-limiting device on SM1, SM2, SM5 and SM10 concert hoists is a slip clutch that is integrated
into the design of the hoist motor and brake. The slip clutch is adjustable for wear and offers these
features:
If the clutch slips, once power is removed the brake will engage and hold the load.
In the absence of a limit switch, the slip clutch also serves as a safety device for over-travel for
the upper and lower limits of hoist travel. The hoist body, made from high density-die cast
aluminum, is designed to withstand the impact of load block and chain-stop.
Overload limiting device
The torque-limiting device on SM16, SM20 and SM25 concert hoists is integrated into the design of the
hoist multistage gear train.
Main
shaft
Brake
Clutch adjusting
nut
Slip-clutch and electromagnetic
brake (SM1, SM2, SM5, SM10)
Torque-limiting device in the
gear train (SM16, SM20, SM25)
