Pneumatic actuation
SITEMA - Safety Brakes
Technical Information
TI-B10-EN-04/2009
SITEMA GmbH & Co.KG . Im Mittelfeld 10 . D-76135 Karlsruhe . Phone: +49 (0)721 98661-0 . Fax: -11 . www.sitema.com 3/3
In all other operational conditions, as well as in cases of power
failure, emergency stop, etc. the Safety Brake becomes effective,
secures the shaft and/or stops the load. In case the pressure
line should fail, the load is secured in the same way. If
necessary the valve can also be switched by another safety signal,
e.g. speeding, contouring error, etc. In these circumstances,
the KSP Safety Brake operates as a generic emergency
brake.
Monitoring by proximity switches
The proximity switch 1 'Load secured' signals the secure state
and is used to authorise entrance to the danger area. Switch 2
'released' is used to activate the downward movement of the
drive.
For automatic detection of failures both signals are compared.
In case both switches indicate the same state - apart from minor
overlapping periods - there is a defect present.
4 Choosing the right size
The admissible load M is stated for all types in the Technical
Data Sheet TI-B11 During normal conditions (vertical movement),
the criteria load is to be maintained.
The holding (braking) force for dry running or mineral-oil wetted
shafts is not less than 2 x M, but will not exceed 3,5 x M. The
fixing elements which accept the load (e.g. linking the rod to the
travelling tool etc.) must therefore be dimensioned for a 3.5 x
M force. This maximum force can occur with emergency braking
and also if, in case of control errors , the fuill driving force is
exerted against the KSP Safety Brake. However circumstances
of this kind should remain accidental exceptions, as otherwise
possible damage could occur to the KSP Safety Brake.
5 Rod requirements
The KSP Safety Brake is designed for operation on smooth
round rods.
Fig. 6: Rod end with lead-in chamfer
Rod design requirements:
The rod end is fitted with a lead-in chamfer (min. 3×20°,
rounded) as a mounting aid.
The rod surface is hardened (at least HRC 52), burnished
and within ISO tolerance f7 or h6 and a surface finish Rz=
1 to 4 ėm or Ra 0.15 - 0.25 ėm
The material has a yield strength sufficient to withstand
the maximum posible load (up to 3.5 x M, see § "Dynamic
braking of a falling mass"). In the case of compressionloaded
rods buckling resistance must be assured.
Most recommended are:
Piston rods, hard chrome-plated (ISO-tolerance f7 or h6)
basic material: yield strength min 580 N/mm˛
induction-hardened HRC 52 - 64 / min. 1 mm deep
hard chrome plating: 800-1100 HV min 13 ėm thickness
surface finish: Ra 0.15 - 0.25 ėm
6 Operating conditions
The KSP Safety Brake is designed to operate in usual clean
and dry shop atmosphere. In case of other environments at
least the port T for breathing purposes is to be connected to a
clen and dry volume (tank).
Should heavy soiling conditions (grinding dust, chips, other liquids,
etc.) exist, please contact SITEMA.
Grease on the rod may reduce the holding force. The permissible
ambient temperature is 0 - 60°C.
7 Required risk assessment
If SITEMA - Safety Brakes are used in safety-relevant
applications the following has to be carefully attended:
It must be ensured that the size, the dimensions and
arrangement of SITEMA - Safety meet the requirements of the
risk evaluation EN ISO 14121-1 for the complete machine and
also comply with any further standards and regulations
applying to the intended use. This is generally the duty of the
system manufacturer/user.
8 Overall documentation and CE
mark
The KSP Safety Brake is designed as a component for integration
into a machine or system. The seller of the machine or system
must provide information on the KSP Safety Brake with the
overall documentation and - if applicable - ensure that the machine
or system carries the CE mark.
9 Regular functional checks
The KSP Safety Brake must be functionally checked at regular
intervals. Regular checking is the only way to ensure that the
unit will operate safely in the long run.
Please see Operating Manual BA-B10 for further details.
10 Maintenance
The maintenance of the SITEMA Safety Brakes is limited to the
prescribed regular functional check.
Should the KSP Safety Brake cease to comply with the required
characteristics, the aforementioned safety of working with the
machine or system is no longer given. In this case the KSP
Safety Brake must be removed immediately and professionally
repaired by SITEMA.
Any repair or refurbishing must be carried out by SITEMA.
SITEMA cannot take any responsibility for repairs by another
party.
M Moving weight
Number of
safety brakes
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