Zato CAYMAN FCE II Series, Руководство по безопасности, эксплуатации и техническому обслуживанию

Страница: 70 / 96

70 / 96
CAYMAN
Version 01 - Revision 00
09/05/2017
7.2.2.11
how to make sure the blade screws and bolts are tightened properly
should loose bolts be found too often, contact the Manufacturer.
do not use nuts and bolts made of material different from the original material or with different
characteristics�
do not break the bolts by tightening them with a torque wrench; this could break the wrench or
throw off its calibration� When using a torque multiplier with a torque wrench, incorrect wrench
settings are multiplied by the set ratio�
To ensure the correct tightening of the screws and bolts, or to periodically check tightness, only
use a suitably rated torque wrench, after having carefully read the instructions provided with
the wrench�
Torque wrenches must be calibrated annually�
Tightened bolts stretch, with a corresponding decrease in resistance, which compromises the
hold of the bolts themselves� As such, all bolts can only be tightened twice, after which they
need to be replaced�
Proper screw and bolt tightening is fundamental for the connection to work safely�
An over-tightened joint may, in fact, cause permanent plastic deformation that affects the solidity of the
connection�
An under-tightened joint can cause subsidence due to fatigue, loosening and relative sliding of the joined
parts and consequent cutting of the bolt, vibrations and shaking of the joined parts�
Bolts must be tightened correctly by rotating the nut and not the screw head�
The table below shows the correct tightening torque values for screws and bolts�
type Class 8.8 Class 10.9 Class 12.9
M6 x 1 10�4 Nm 15�3 Nm 17�9 Nm
M8 x 1.25 25 Nm 37 Nm 44 Nm
M10 x 1.5 50 Nm 73 Nm 86 Nm
M12 x 1.75 86 Nm 127 Nm 148 Nm
M14 x 2 137 Nm 201 Nm 235 Nm
M16 x 2 214 Nm 314 Nm 366 Nm
M18 x 2.5 305 Nm 435 Nm 509 Nm
M20 x 2.5 432 Nm 615 Nm 719 Nm
M24 x 3 744 Nm 1,060 Nm 1,240 Nm
M27 x 3 1,100 Nm 1,570 Nm 1,840 Nm
M30 x 3.5 1,500 Nm 2,130 Nm 2,500 Nm
tab. 14 Tightening torque values