means shall be provided to prevent the load from falling
in the event of loss of brake actuating power.
(c) When a hoist is to be operated from a remote
location, a self-setting brake shall be provided to prev,ent
drum rotation in the event of power failure. This
requirement does not apply to hoists where brakes are
manually applied through mechanical linkages and the
operator is at the control position.
(d) Foot operated brakes shaH be constructed so that
the operator's foot will not easily slip off the pedal.
(e) Swinger brakes shaH have holding power in both
directions to prevent movement of the rotating member
of the load-handling equipment. The brake shall be
capable of being set in the holding position and remaining
so without attention on the part of the operator.
(/) A power control braking means (such as regenerative,
dynamic, countertorque braking, or power controlled
lowering) or a mechanically controBed braking
means shaH be provided and shall be capable of maintaining
controlled lowering speeds.
7-1.2.4 Adjustments. Brakes and clutches shall
be provided with adjustments where necessary to compensate
for wear and to maintain tension in springs
where used.
7-1.2.5 Guards
(a) Exposed moving parts, such as gears, set screws,
projecting keys, chains, chain sprockets, and reciprocating
or rotating parts, which might constitute a hazard
under normal operating conditions, shall be guarded.
(b) Guards shall be fastened.
(c) Guards shall be capable of supporting, without
permanent distortion, the weight of a 200 Ib (90 kg)
person unless the guard is located where it is unlikely
that a person will step on it.
7-1.2.6 Ropes
(a) Ropes shall be of a size, grade, and construction
to withstand the loads imposed. Fiber ropes may be
used only with the manufacturer's or qualified person's
recommendations.
(b) Ropes shall be of a length for the entire range
of movement specified for the application, with no less
than two full wraps of rope on the drum at all times.
(c) The design factor for ropes, except rotation resistant
ropes, shall be not less than 3.5. The design factor
for rotation resistant ropes shall be not less than 5.
[The design factor of 5 or greater for rotation resistant
ropes may be modified by the hoist user by complying
with the provisions of para. 7 -3.2.1 (b).]
10
ASME 830.7-2001
NOTE: ASME 830.6 requires a minimum design factor of 3.5:1 for
running ropes used with derricks. ANSI A 10.5 requires a minimum
design factor for ropes of 7: I.
(d) Wherever exposed to temperatures in excess of
180°F (82°C), rope having an independent wire rope
or wire strand core, or other temperature damageresistant
core shall be used.
(e) The rope (right or left lay) should be selected
in accordance with the drum rotation and anchorage.
7-1.2.7 Controls
(a) All controls used during the normal operating
cycle shall be located within reach of the operator
while at the operator's station. Arrangement of controls
should be in accordance with applicable requirements
of SAE J983.
(b) Electric motor operated hoists shall be provided
with a device which will disconnect all motors from
the line on failure of power, and will not permit any
motor to be restarted until the controller handle is
brought to the off position, or a reset switch or button
is operated.
(c) Electric motor operated hoists which are capable
of overspeeding the power plant on overhauling regenerative
loads shall be provided with means to prevent
such overspeeding.
(d) Remote operated base-mounted drum hoists shall
function so that if the control signal for any hoist
motion becomes ineffective, that hoist motion shall stop.
7-1.2.8 Prime Mover Controls. Controls for operating
the prime mover shall be within reach of the
operator and shall include means to:
(a) start and stop;
(b) control speed of internal combustion engines or
drive motors;
( c) stop two-cycle internal combustion engines or
drive motors under emergency conditions;
(d) shift selective transmissions when used.
7-1.2.9 Control Forces and Movements. When
a hoist is operated within the manufacturer's ratings,
the following shall apply under normal operation.
(a) Forces not greater than 35 Ib (156 N) on hand
levers and forces not greater th,m 50 lb (222 N) or
less than 8 lb (36 N) on foot pedals.
(b) Travel distance on hand levers not greater than
14 in. (356 mm) from neutral position on two-way
levers, and not greater than 24 in. (610 mm) on oneway
levers; travel distance on foot pedals not greater
than lOin. (254 mm).