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stainless steel. In the plant, 20kg wheels of cheese
are transported into the ripening cellar at a speed of
2 m/s via an 8m high elevator. Two linear brakes in
pneumatic design with a holding force of 50,000 N
each secure the elevator. They not only hold the
load, but can also bring it to a standstill within
fractions of a second in case of an emergency – for
example, if the drive belt rips. The redundant design
ensures the necessary safety.

Securing vertical axes reliably
When securing gravity loaded axes such as in the
example of the vertical conveyor, linear brakes like
the ROBA-linearstop have proven particularly
efficient, as they take effect on separate brake rods
independent of the drive line. In this way, there are
no toothed belts, couplings or spindle nuts in the
safety drive line of the brake. Just like all safety
brakes by Mayr, also the linear brakes work
according to the fail-safe principle. This means they
are closed in de-energised condition. The braking
force is generated by thrust springs.
The ROBA-linearstop works without a self-
reinforcing wedge effect and therefore acts in both
directions of movement. Due to the generation of electromagnetic design. In this way, the appropriate
force without "sticking" and the extremely short functional principle can be selected for each
reaction time, the axis does not drop suddenly on application case. As a compact brake unit it can be
closing. Other linear brake systems which work integrated into already existing machinery and
using a self-reinforcing wedge effect may generate a system constructions easily, quickly and without
high braking force. extensive adjustment work.
But this wedge effect only works in one direction
and to generate the wedge effect, the brake has to Short switching times
‘settle’ on closing. If the wedge effect of the brake is In particular on vertical axes, short stopping
not limited, the braking force increases infinitely. distances are important for the safety of people and
The machine structure then has to absorb the machines. The brake switching times are decisive
impact. Moreover, in many cases the clamping for the braking distance, as the mass additionally
mechanism then has to be moved clear for brake accelerates in the time of free fall until the brake
release. This is not the case with the ROBA- closes and retardation begins.
linearstop. “When selecting linear brakes, users should
In addition to the pneumatic versions, Mayr also therefore make sure that the verified switching
offers the ROBA-linearstop in hydraulic and times are as short as possible”, explains Bernd

April 2020 • INDUSTRIAL TECHNOLOGY EXTRA! • p21