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Which is better? It depends on your application. As a general rule
we have found that 3 ton is a typical crossover point. Below 3 ton we
usually recommend chain, above we usually recommend wire rope.
Your application has a great effect on whether this
holds true.
Some reasons one may work better than the other:
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Side pull. Although manufacturers recommend that you
only lift straight up, there are applications where some lifting at an
angle is required. Chain hoists are much more forgiving for these
applications.
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High speeds. Except at low capacities chain hoists
are not available at high speeds.
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High frequency of use. Although many chain hoists
are rated for heavy duty cycle our experience has been that chain has
higher maintenance cost with high duty cycle.
How fast should your hoist
lift? Lift speed is usually based on the height the product will be lifted,
the frequency of lifts, and how delicately the product must be set down
(this can also be accomplished with 2 speed or variable speed).
Increasing the speed can increase the cost of a hoist
significantly so it is important to weigh the cost of slower operation with
the cost of the hoist. As an example if you are lifting to the back of a
truck you will need to lift about 5 feet. If you are lifting 20 times per
hour, 5 days a week, and using a hoist with a lift speed of 10 FPM you will
use (5lifts X 2 (up and down)/10 FPM /60 minutes per hour ) X 20 times per
hour X 5 days per week X 52 weeks per year X $20.00 burdened hourly rate =
$1,733.33 per year for labor cost. If you purchased a 20 FPM hoist you
would save ˝ of this or $866.67 per year.
The other factor in choosing a slower hoist is
impatience. I have very little patience when lifting a slow moving load
that takes 1 minute to lift high enough to place on a truck.
A
manual chain hoist is much less expensive than a motorized hoist. Manual
hoists should be considered when speed is not important and when lifts are
very infrequent. When lifting heavier loads you should consider the fact
that in order to lift a 5 ton load by hand you must pull over 200 feet of
chain at 80 pounds of force to lift 1 foot.
If you need a
trolley do you want push, hand geared, or motorized?
Push is much less expensive but if used in applications
where operator cannot push from behind the load (if traveling over tanks),
or if used frequently or with heavy loads (2 tons or over) can cause fatigue
or back injury.
Geared trolleys are somewhat less expensive than
motorized. The chain used to drive the wheels can get in the way in many
applications.
Motorized trolleys are more expensive but have the
advantage of ease of motion. If you decide on motorized trolley you need to
specify the size of beam they will ride on and the speed you wish.
Increasing speed on trolley typically does not increase the cost but load
swing should be taken into account if fast speeds are used (a variable drive
is useful with fast speeds). Slow speeds are typically about 30 FPM, medium
about 60 FPM and fast over 100FPM.
Which brand is best? This
depends on you application. We have found that every brand tends to have a
market segment that do best in. Check the brand section of our web sight
for mare information.
There are many options available on
hoists. Whether an option is cost effective depends on your application.
The following is a list of some more frequently used options:
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Chain container.
Used on most electric chain hoists to store the extra chain.
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Pendant operated horn to
warn others of danger. OSHA states that crane systems “should”
have a horn. “Should” is not mandatory but we strongly recommend it.
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Strobe light
activated on motion
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Add multistep infinitely
variable speed control. With variable speed control the speed
ramps up and down at a programmed rate reducing load swing. Variable
drives also allow very slow speeds when positioning loads, medium speeds
when traveling with large loads or fast speeds when traveling empty.
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Faster trolley.
There typically is little of no added cost for the faster speed on the
trolley but we recommend the variable drive when using faster speeds to
reduce swing and allow easy positioning of the load.
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Two speed hoist.
Typically we do not recommend variable drive on the hoist. The hoist
typically have a high horsepower motor which requires an expensive
variable drive. The slow speed of a two speed hoist is typically slow
enough for all uses except the most precise. There are 2 standard ratios
with 2 speed hoists 3 to 1 and 5 to 1. We recommend the 5 to 1 in most
instances because it provides a slower speed for positioning. ( Some
manufacturers offer a creep 10 to 1 ratio. This is extremely slow and not
very useful. We would recommend a variable drive if you need this kind of
control)
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Explosive environments.
When used in explosive environments a Group, Class, and Division must be
specified. (call for paperwork explaining what these mean) Explosion
proof hoists are very expensive. One less costly way of achieving
explosion proof is with an air operated hoist.
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Spark resistant.
This is a completely different option from explosion proof. Typically
this includes Stainless of bronze wheels, chain, and hooks.
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Remote control.
Cost of remotes has come down recently as reliability has increased. Most
modern remotes have a set frequency as well as a verification number that
is sent with each signal. The carrier number is verified before the
receiver will process any signal. Remotes are used in many areas where a
pendant hanging from the hoist is not practical or efficient.
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Dual brake. Many
hoists come with a separate mechanical load brake in the gear box.
Although a single load brake is adequate in critical applications or for
customers who feel more comfortable with a secondary brake this is a good
option to consider.
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Limit switches.
Although all manufacturers still do not add upper and lower limit switches
as standard OSHA has stated that upper limit switches are mandatory
(several manufactures have tried to skirt this by using an overload device
as the limit which OSHA has clarified as not adequate.) Lower limits are
required in some instances and we recommend them in all applications.
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Trolley brakes or non-
coasting mechanism are required on hoists used on cranes.
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Space heaters are
not used in most hoists indoors but are important if the hoist is used and
stored outside in and environment where the sun will heat the hoist during
the day and the moist cold night air will bring water into the motors or
controls
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Fusing. Branch
fusing is required when on a crane. This means one set of fuses for the
hoist and one for the trolley
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Mainline disconnect operated
from the pendant is required when used on a crane and we
recommend it on all uses. This allows the operator to quickly cut the
power to the hoist if a relay ever sticks. We recommend a momentary
disconnect type if used.
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Trolley safety lugs and
bumpers are required on cranes and recommended on all uses.
Adverse environments,
Corrosive, explosive, high temperature, etc., should be considered in the
purchase of your hoist. We recommend you contact one of our sales
representatives if you have any concerns. Options such as epoxy paint,
stainless or zinc chain and hooks, rain covers should be considered in harsh
environments.
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