B-Top
Use and limits of use
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31
From this, the initial clamping force while stationary can be
derived:
𝐹
𝑠𝑝0
= 𝑆
𝑠𝑝
∗ (𝐹
𝑠𝑝
± 𝐹
𝑐
)[𝑁]
(+) for clamping from outside inwards
(-) for clamping from inside outwards
NOTE
Material damage to the clamping device and ma-
chine tool caused by exceeding the clamping
force!
The calculated force must not exceed the maxi-
mum clamping force
∑ 𝑆
that is engraved on the
product [see »General information« chapter].
From the above formula, it is evident that the sum total of
effective clamping force
𝐹
𝑠𝑝
and total centrifugal force
𝐹
𝑐
is
multiplied by the safety factor for clamping force
𝑆
𝑠𝑝
. In ac-
cordance with VDI 3106 the following also applies here:
𝑆
𝑠𝑝
≥ 1.5
.
The total centrifugal force
𝐹
𝑐
is dependent upon the sum total
of the masses of all jaw chucks and upon the radius of center
of gravity as well as the rotational speed.
INFORMATION
For safety reasons, DIN EN 1550 stipulates that the
centrifugal force must not exceed a maximum of 67%
of the initial clamping force.
The formula for calculating the total centrifugal force
𝐹
𝑐
is as
follows:
𝐹
𝑐
= ∑(𝑚
𝐵
∗ 𝑟
𝑠
) ∗ (
𝜋∗𝑛
30
)
2
= ∑𝑀
𝑐
∗ (
𝜋∗𝑛
30
)
2
[𝑁]
Here, n is the given speed in rpm. The product
𝑚
𝐵
∗ 𝑟
𝑠
is des-
ignated as the centrifugal torque
𝑀
𝑐
.
𝑀
𝑐
= 𝑚
𝐵
∗ 𝑟
𝑠
[𝑘𝑔𝑚]
On clamping devices with split chuck jaws [with a base jaw
and a top jaw] on which the base jaws only alter their radial
position by the extent of stroke, centrifugal torque of base
jaws
𝑀
𝑐𝐺𝐵
and centrifugal torque of top jaws
𝑀
𝑐𝐴𝐵
are added
together:
𝑀
𝑐
= 𝑀
𝑐𝐺𝐵
+ 𝑟
𝑠
[𝑘𝑔𝑚]
For the centrifugal torque of the base chucks
𝑀
𝑐𝐺𝐵
see the
»General information« chapter. The centrifugal torque of the
top jaws
𝑀
𝑐𝐴𝐵
is calculated in accordance with:
𝑀
𝑐𝐴𝐵
= 𝑚
𝐴𝐵
∗ 𝑟
𝑠𝐴𝐵
[𝑘𝑔𝑚]
