Selection Of The Safe Working Load (Swl) - Pfeifer Polytex Traducción Del Manual Original

Neigungswinkel > 60° Tilt angle > 60°
sind unzulässig! are not allowed!
Fig. 16
• With a symmetric load distribution, equal leg lengths
and equal angles of inclination ß, only three legs of
a 4-leg suspension gear may be assumed to be
load-carrying according to DGUV rule 100–500.
• With an asymmetric load distribution and/or unequal
angles, only one leg may be assumed to be load-
carrying in the case of 2-leg suspension gear and only
two legs in the case of 3-leg or 4-leg suspension gear.
• If lifting straps are used in pairs, it is recommended to
use a cross bar so that the load is evenly distributed.
• When attaching lifting straps, make sure that
– the entire width of a lifting strap is evenly loaded.
– parallel shear pull does not occur. This is
impermissible!
– the lifting strap can be dismounted without
damage after the lifting process.
• Lifting straps must not be installed in a twisted or
knotted state or extended by tying them together.
• Connect or extend lifting straps only using suitable
shackles or round sling hooks.
• An opening angle of the shape-B lifting strap end
loops greater than 20° is not permitted. The loop
length must be at least three and a half times the size
of the contact surface „d" of the crane hook during
use, otherwise the seam of the lifting strap loop can
tear open.
Fig. 17
• When lifting sharp-edged loads (see definition of
a sharp edge), lifting straps must be protected with
suitable protective sleeves.
• Lifting straps must neither be placed on sharp edges
nor slide or be pulled over them. The lifting strap can
be severed, resulting in the load falling (see definition
of a sharp edge). Due to sliding on a sharp edge,
edge protection systems or coatings can also be
destroyed and thus also the lifting strap!
Polytex flat slings 12/2021 / subject to change!
10 ®
Last
Load
20°
• Definition: An edge is considered to be sharp if the
edge radius R is smaller than the thickness D of the
attachment device!
Fig. 18
Asymmetric load distribution is always to be expected
when
• the load is inelastic (e. g. concrete parts, castings,
short beams, etc.)
• the position of the centre of gravity is not known
• the load is unevenly shaped
• different angles of inclination ß occur
8.2 Selection of the safe working
load (SWL)
• Taking into account the reduction factors, the safe
working load (SWL) of the lifting strap must be
greater than or equal to the weight of the load.
• The rigging method and angles of inclination of the
lifting procedure must already be considered when
selecting the lifting straps.
• The lifting strap must contact the load lifting attachment
(e. g. crane hook) and the load over its entire width.
• If loop lifting straps are used, the minimum length of
the loop for a lifting strap attached to a hook must be
at least 3.5 times the maximum thickness of the
hook.
• If a loop lifting strap is connected to a lifting device, it
is essential that the part of the lifting device to which
the lifting strap is attached is straight. An exception is
if the load-carrying width of the lifting strap is less
than 75 mm, and in this case the radius of curvature
for attachment to the lifting device must be at least
0.75 times the load-carrying width of the lifting strap.
• Fig. 20 shows the attachment of a strap to a hook
whose radius is less than 0.75 times the load-carry-
ing width of the lifting strap. Wide straps can be
damaged by a radius that is too small, i. e. too much
curvature on the inside of the hook, due to there being
no uniform load on the strap over its width.
60°
Fig. 19