EN 12622:2001

SLOVENSKI STANDARD
01-januar-2002
Safety of machine tools - Hydraulic press brakes
Safety of machine tools - Hydraulic press brakes
Werkzeugmaschinen - Sicherheit von Werkzeugmaschinen - Hydraulische -
Gesenkbiegepressen
Sécurité des machines-outils - Presses plieuses hydrauliques
Ta slovenski standard je istoveten z: EN 12622:2001
ICS:
25.120.10 Kovaški stroji. Stiskalnice. Forging equipment. Presses.
Škarje Shears
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 12622
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2001
ICS 25.120.10
English version
Safety of machine tools - Hydraulic press brakes
Sécurité des machines-outils - Presses plieuses Sicherheit von Werkzeugmaschinen - Hydraulische
hydrauliques Gesenkbiegepressen
This European Standard was approved by CEN on 7 March 2001.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12622:2001 E
worldwide for CEN national Members.

Page 2
Contents
Foreword. 3
0 Introduction. 3
1 Scope. 3
2 Normative references . 4
3 Definitions and abbreviations. 5
4 List of significant hazards . 9
5 Safety requirements and/or protective measures. 12
6 Verification of the safety requirements and/or protective measures . 28
7 Information for use. 32
Annex A (normative) Calculation of minimum safety distances. 34
Annex B (normative) The response time of the press brake stopping performance . 36
Annex C (informative) Example of redundant and monitored hydraulic control circuits for a
downstroking press brake. 37
Annex D (informative) Conditions for noise measurement of press brakes . 38
Annex E (informative) The connection of the stopping time measurement equipment during press brake
construction. 39
Annex F (informative) Side safeguarding for manually fed press brakes . 40
Annex G (informative) Markings . 41
Annex ZA (informative) Relationship of this document with EC Directives. 42
Bibliography . 43

Page 3
Foreword
This European Standard has been prepared by Technical Committee CEN/TC 143 "Machine tools - Safety",
the secretariat of which is held by SNV.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by October 2001, and conflicting national standards shall be withdrawn at
the latest by October 2001.
This European Standard has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association, and supports essential requirements of EC Directive(s).
For relationship with EC Directive(s), see informative Annex ZA, which is an integral part of this standard.
Annexes A and B to this standard are normative, whereas annexes C to G and ZA are informative.
This standard also contains a “Bibliography”.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland and the United Kingdom.
0 Introduction
0.1
This standard is applicable to hydraulic press brakes as defined in 3.1.9.
0.2
This standard has been prepared to be a harmonized standard to provide one means of conforming
with the essential safety requirements of the Machinery Directive 98/37/EEC and associated EFTA
Regulations. It is a type C standard as described in EN 292–1:1991.
0.3 The extent to which hazards are covered is indicated in the scope of this standard.
0.4 Complementary guidance is given in the type A and type B standards to which reference is made in
the text (see clause 2). The figures are intended to be examples only and not to give the only interpretation of
the text.
1 Scope
1.1 This standard specifies technical safety requirements and protective measures to be adopted by
persons undertaking the design (as defined in 3.11 of EN 292-1:1991), manufacture and supply of hydraulic
press brakes which are intended for cold working of metal or material partly of metal.
1.2
This standard also covers hydraulic press brakes, whose primary intended use is the cold working of
metal, which are to be used in the same way to work other sheet materials such as cardboard or plastic.
1.3 The requirements in this standard take account of intended use, as defined in 3.12 of EN 292-1:1991.
This standard presumes access to the press brake from all directions, deals with the hazards described in
clause 4, and specifies the safety measures for both the operator and other exposed persons.
1.4
This standard also applies to ancillary devices which are an integral part of the press brake, e.g. back
gauges and adjustable front sheet supports. For the safeguarding of integrated manufacturing systems using
press brakes, see also prEN 1921: 1995.
1.5 This standard does not cover machines whose principal designed purpose is:
a) sheet folding by rotary action;
b) tube and pipe bending by rotary action;
c) roll bending.
1.6 This standard applies to machines built after its date of issue.
NOTE An amendment is under preparation to take into account the use of laser/scanner devices for the
safeguarding of operators on press-brakes.

Page 4
2 Normative references
This European standard incorporates, by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to
this European standard only when incorporated in it by amendment or revision. For undated references, the
latest edition of the publication referred to applies (including amendments).
EN 292-1:1991 Safety of machinery - Basic concepts, general principles for design -
Part 1: Basic terminology, methodology
EN 292-2:1991 Safety of machinery - Basic concepts, general principles for design -
+A1:1995 Part 2: Technical principles and specifications
EN 294:1992 Safety of machinery - Safety distances to prevent danger zones being reached by the
upper limbs
EN 349:1993 Safety of machinery - Minimum gaps to avoid crushing of parts of the human body
EN 418:1992 Safety of machinery - Emergency stop equipment, functional aspects - Principles for
design
EN 563:1994 Safety of machinery - Temperatures of touchable surfaces - Ergonomics data to
establish temperature limit values for hot surfaces
EN 574:1996 Safety of machinery - Two-hand control devices - Functional aspects, Principles for
design
EN 614-1:1995 Safety of machinery - Ergonomic design principles - Part 1: Terminology and general
principles
EN 894-2:1997 Safety of machinery - Ergonomics requirements for the design of displays and control
actuators -
Part 2: Displays
EN 894-3:2000 Safety of machinery - Ergonomics requirements for the design of displays and control
actuators -
Part 3: Control actuators
EN 953:1997 Safety of machinery – Guards - General requirements for the design and construction
of fixed and movable guards
EN 954-1:1996 Safety of machinery - Safety related parts of control systems -
Part 1: General principles for design
EN 982:1996 Safety of machinery - Safety requirements for fluid power systems and their
components - Hydraulics
EN 983:1996 Safety of machinery - Safety requirements for fluid power systems and their
components - Pneumatics
EN 999:1998 Safety of machinery – The positioning of protective equipment in respect of approach
speeds of parts of the human body
prEN 1005-2:1998 Safety of machinery - Human physical performance -
Part 2: Manual handling of machinery and components parts of machinery
EN 1050:1996 Safety of machinery - Principles for risk assessment
EN 1088:1995 Safety of machinery - Interlocking devices associated with guards - Principles for
design and selection
EN 1837:1999 Safety of machinery - Integral lighting of machines
prEN 1921:1995 Industrial automation systems - Safety of integrated manufacturing systems - Basic
requirements (ISO 11161:1994 modified)
EN ISO 3746:1995 Acoustics - Determination of sound power levels of noise sources using sound
pressure - Survey method using an enveloping measurement surface over a reflecting
plane (ISO 3746.2:1995)
Page 5
EN ISO 4871:1996 Acoustics – Declaration and verification of noise emission values of machinery and
equipement
EN ISO 11202:1995 Acoustics - Noise emitted by machinery and equipment - Measurement of emission
sound pressure levels at the work station and at other specified positions - Survey
method in situ (ISO 11202:1995)
EN ISO 11688-1:1998 Acoustics - Recommended practice for the design of low-noise machinery and
equipment -
Part 1: Planning (ISO/TR 11688:1995).
EN ISO 14122:2001 Safety of machinery - Permanent means of access to
machines and industrial plants
Part 1: Choice of a fixed means of access between two levels
Part 2: Working platforms and gangways
Part 3: Stairways, stepladders and guard-rails
prEN ISO 14122:1999 Safety of machinery - Permanent means of access to machines and industrial plants
Part 4: Fixed ladders
EN 60204-1:1997 Safety of machinery - Electrical equipment of machines -
Part 1: General requirements (IEC 60204-1:1997)
EN 60529:1991 Degrees of protection provided by enclosures (IP code) (IEC 60529:1989)
EN 60825–1: 1994 Safety of laser products –
Part 1: Equipment classification, requirements and user's guide (IEC 60825:1993)
EN 61310-2:1995 Safety of machinery - Indication, marking and actuation -
Part 2: Requirements for marking (IEC 61310-2:1995)
EN 61496-1:1997 Safety of machinery – Electro-sensitive protective equipment -
Part 1: General requirements and tests (IEC 61496–1:1997)
prEN 61496-2:1997 Safety of machinery – Electro-sensitive protective equipment -
Part 2: Particular requirements for equipment using active opto-electronic devices
3 Definitions and abbreviations
3.1 Terms and definitions
For the purposes of this standard, the following definitions apply. Further definitions are provided in relevant
type A and type B standards and in annex A of EN 292-2:1991/A1:1995.
3.1.1
beam
main reciprocating press brake member which normally holds the punch on a downstroking press brake, and
which normally holds the die on an upstroking press brake
3.1.2
blanking
feature available for ESPEs using AOPDs in the form of light curtains in which some parts of the sensing field
can be deactivated
3.1.3
cycle – automatic
operating mode where the operating cycle is repeated continuously or intermittently, all functions achieved
without manual intervention after initiation
3.1.4
cycle – operating
movement completed by the moving part of the tools from the cycle start position (normally the top dead
centre) to the bottom dead centre and back to the cycle stop position (normally the top dead centre). The
operating cycle includes all operations carried out during this movement.

Page 6
3.1.5
cycle – single
operating mode where each operating cycle of the moving part of the tools has to be positively actuated by the
operator
3.1.6
dead centres
points at which the punch on a downstroking press brake is
– either nearest/closest to the die, known as the bottom dead centre (BDC),
– or furthest from the die, known as the top dead centre (TDC).
On an upstroking press brake, the centres are reversed.
3.1.7
early opening interlocking guard
guard associated with an interlocking device which, if opened when any hazardous movement in the tools area
has ceased, does not interrupt the operating cycle
3.1.8
guard locking device
mechanical device to maintain an interlocking guard gate in the closed and locked position until the risk of
injury from the hazardous machine functions has passed
3.1.9
hydraulic press brake
machine designed or intended to transmit energy to the moving part of the tools by hydraulic means principally
for the purpose of bending between narrow forming tools along straight lines (see figure 1)
3.1.10
limited movement control device; inching device
control device, the actuation of which permits only a limited amount of travel of a machine element, thus
minimizing risk as much as possible; further movement is precluded until there is a subsequent and separate
:
actuation of the control. [3.23.8 of EN 292-1 1991]
3.1.11
monitoring
safety function which ensures that a safety measure is initiated if the ability of a component or an element to
perform its function is diminished, or if the process conditions are changed in such a way that hazards are
generated
3.1.12
muting
temporary automatic suspension of a safety function(s) by safety related parts of the control system [3.7 of EN
954-1:1996]
3.1.13
overall system stopping performance; overall response time
time occurring from actuating the protective device to the cessation of hazardous motion, or to the machine
assuming a safe condition
Page 7
3.1.14
position switch
switch which is operated by a moving part of the machine when this part reaches or leaves a predetermined
position
3.1.15
redundancy
application of more than one device or system, or part of a device or a system, with the objective of ensuring
that, in the event of one failing to perform its function, another is available to perform that function [3.44 of EN
60204-1:1998]
3.1.16
restraint valve
device which protects against a gravity fall of the beam
3.1.17
single stroke function
feature used to limit the motion of the moving part of the tools to one operating cycle even if the stroke
initiating means (e.g. a pedal) is held in the operating position
3.1.18
tools
term for the combination of punch and die
3.1.19
tools – closed
tools designed and constructed to be inherently safe
3.1.20
up–stroking press brake
press brake in which the lower tool moves upwards during the closing stroke (reciprocal to a down–stroking
press, see figure 1)
Page 8
Key Figure 1 - Example of a downstroking hydraulic press brake
1 : Press cylinder 6 :Backstop 11: Side Safeguard
2 :Control panel 7 :Hydraulic System 12 : Light Curtain
3 : Electircal Switch Gear Cabinet 8 :Beam 13 : Frame
4 :Foot pedal 9 :Tools
5 :Workpiece Support 10 : Bed
3.2 Abbreviations
3.2.1
M
Monitoring (see 3.1.11)
3.2.2
R
Redundancy (see 3.1.15)
3.2.3
S
Single system
3.2.4
BDC
Bottom dead centre (see 3.1.6)
3.2.5
TDC
Top dead centre (see 3.1.6)
3.2.6
PES
Programmable electronic systems

Page 9
3.2.7
PPS
Programmable pneumatic systems
3.2.8
AOPD
Active opto-electronic protective devices
3.2.9
ESPE
Electro-sensitive protective equipment
3.2.10
THCD
Two-hand control device
4 List of significant hazards
4.1 The list of hazards contained in table 1 is the result of a hazard identification, their associated danger
zones and reference to protective measures for hydraulic press brakes covered by the scope of this standard.
The safety requirements and/or protective measures and information for use contained in clauses 5 and 7 are
based on a risk assessment and deal with the identified hazards by either eliminating them or reducing the
effects of the risks they generate.
4.2
The risk assessment assumes foreseeable access from all directions, as well as unexpected and
unintended strokes or gravity falls. Risks to both the operators and other persons who can have access to the
danger zones are identified, taking into account hazards which can occur under various conditions of intended
use (e.g. commissioning, tool setting, production, maintenance, repair, decommissioning, dismantling – see
also 3.11 of EN 292–1:1991) during the life of the machine. The assessment includes an analysis of the effect
of failure in the control system.
4.3
The user of this standard (i.e. the designer, manufacturer, supplier) shall check that the list of
significant hazards in table 1 is complete for the machine under consideration. If the user determines that
there are additional hazards then he shall analyse and evalute the risks associated with these hazards in
accordance with EN 1050:1996 with particular attention to the intended use of the machine (e.g.
commissioning, tool setting, production, maintenance, repair, decommissioning, dismantling – see also 3.11 of
EN 292–1: 1991), and its reasonably foreseeable misuse.

Page 10
Table 1 - Significant hazards, danger zones, protective measures
Relevant Relevant Protective
No. Hazards Danger zone clauses in clauses in measures:
EN 292- EN 292–1: relevant
2:1991/ 1991 clauses in
A1:1995 this standard
1.0 Mechanical hazards Tools and associated area: 1.3 4.2 5.1, 5.3 to 5.5
generated by: - between tools,
(except 1.3.6)
- machine parts or - between the moving and the
workpieces fixed parts of the press
brake,
- moving workpieces
accumulation of energy - between deflecting 1.5.3, 1.6.1, 4.2 5.8.3
inside machinery caused, for workpieces and other parts, 1.6.3
example, by:
- moving gauges,
- elastic elements (springs)
- moving sheet supports
- liquids and gases under
- guards
pressure
1.1 Crushing hazard Outside tools area: 1.3 (except 4.2.1 5.3 to 5.6,
1.3.6)
- from hazardous situation of 7.1.2 i) to l)
falling objects
1.2 Shearing hazard 1.4 (except
1.3 Cutting or severing hazard 1.4.2.3)
1.4 Entanglement hazard 1.5.14
1.5 Drawing-in or trapping hazard
1.6 Impact hazard Moving parts of electrical, 1.3 4.2.1 5.6
hydraulic and pneumatic
equipment
Motor and drive machinery
Mechanical handling device
1.9 High pressure fluid injection Hydraulic systems 1.3.2 4.2.1 5.2.2.4, 5.8.3
or ejection hazard
2.0
Electrical hazards due to:
2.1 Contact of persons with live Electrical equipment 1.5.1, 1.6.3 4.3 5.8.1
parts (direct contact)
(continued)
Page 11
Table 1 (continued)
Relevant Relevant Protective
No. Hazards Danger zone clauses in clauses in measures:
EN 292- EN 292–1: relevant
2:1991/ 1991 clauses in
A1:1995 this standard
2.2 Contact of persons with parts Electrical equipment 1.5.1 5.8.1
which have become live
under faulty conditions
(indirect contact)
3.0 Thermal hazards
3.1 Thermal hazards resulting in Parts of the hydraulic system 1.5.5, 1.5.6, 4.4 5.8.2
burns and scalds, by a 1.5.7
possible contact of persons
4.0 Noise hazards
4.1 Hazards generated by noise Any area at the press brake 1.5.8 4.5 5.8.5
resulting in hearing losses where there is a risk to hearing
(deafness)
6.0 Hazards generated by radiation
6.5 Lasers Any area at the press brake 1.5.12 4.7 5.8.6
where there is a risk due to laser
beams
8.0 Hazards generated by neglecting ergonomic principles in machinery design, as e.g. from:
8.1 Unhealthy postures or 1.1.2d, 1.1.5, 4.9 5.8.8
The working position and any
excessive effort 1.6.2, 1.6.4
area for controls, setting,
maintenance and handling
8.2 Inadequate consideration of 1.1.2 d, 2.2
hand–arm foot–leg anatomy
8.4 Inadequate local lighting 1.1.4 5.8.8.3, 7.2.2 d
8.6 Human error, human 1.1.2 d, 1.2.2, 4.9 5.4.5.1, 5.4.5.4,
behaviour 1.2.5, 1.2.8, 5.4.5.5, 5.4.3,
1.5.4, 1.7 5.4.6
8.7 Inadequate design, location 1.2.2 5.4.5, 5.8.8.2
or identification of manual
controls
8.8 Inadequate design or location 1.7.1 5.8.8.2
of visual display units
10 Unexpected start–up, unexpected overrun/ overspeed
10.1 Failure/disorder of the control Tools and associated area: 1.2.7, 1.6.3 5.2 to 5.5
system
- between tools,
10.2 Restoration of the energy - between the moving and the 1.2.6 5.4.1.1
supply after an interruption fixed parts of the press brake,
- moving workpieces
10.3External influences on- between deflecting work- 1.2.1, 1.5.11 5.4.1
electrical equipment pieces and other parts,
10.5 Errors in the software - moving gauges, 1.2.1 5.4.2, 5.3.12.1f)
10.6 Errors made by the operator - moving sheet supports 1.1.2 d, 1.2.2, 4.9 5.3, 7.2.2
(due to mismatch of 1.2.5, 1.2.8,
- guards
machinery with human 1.5.4, 1.7
characteristics and abilities,
see 8.6 of table 1)
13 Failure of the power supply 1.2.6 5.4.1.1
Failure of the control circuit
14 1.2.1, 1.2.3, 5.2 to 5.5
1.2.4, 1.2.5,
1.2.7, 1.6.3
(continued)
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Table 1 (concluded)
Relevant Relevant Protective
No. Hazards Danger zone clauses in clauses in measures:
EN 292- EN 292–1: relevant
2:1991/ 1991 clauses in
A1:1995 this standard
15 Errors of fitting tools 1.5.4 4.9 5.3.24
16 Break–up during operation Mechanical, electrical, hydraulic 1.3.2 4.2.2 5.2.2.4,
and pneumatic equipment 5.2.2.7,5.2.2.8,
5.2.2.9, 5.4.4
17 Falling or ejected objects Machine components 1.3.3 5.3.24, 5.3.24.1
or fluids
Workpieces and tools
18 Loss of stability/ Floor area around the press 1.3.1 5.8.4, 7.2.2 d)
overturning of machinery brake
19 Slip, trip and fall of persons All access and/or work at heights 1.5.15 4.2.3 5.7
(related to machinery)
Floor area around the press
brake
5 Safety requirements and/or protective measures
5.1 Introduction
The hydraulic press brakes covered by this standard range in size from small high speed machines with a
single operator producing small workpieces to large relatively slow speed machines with several operators and
large complex workpieces.
The methods or measures to be implemented to eliminate the significant hazards (see table 1) or reduce their
associated risks are detailed in this clause in the following manner:
– basic design considerations for major press brake components or systems (see 5.2);
– safeguarding against mechanical hazards in the tools and associated areas under different modes of
production (see 5.3 and tables 2 and 3);
– protection against hazards due to control system or control component failures (see 5.4);
– safeguarding against hazards which can occur during tool setting, trial strokes, maintenance and
lubrication (see 5.5);
– safeguarding against other hazards (see 5.6 to 5.8).
In addition, the machine shall be designed according to the principles of EN 292 for hazards relevant but not
significant which are not dealt with by this standard.
5.2 Basic design considerations
5.2.1 Prevention of unintended gravity fall of the beam during production (downstroking press
brakes)
5.2.1.1 Where there is a risk of injury (force exceeding 150 Newtons), measures shall be provided to prevent
an unintended gravity fall of the beam in the production mode with manual or automatic feed or removal (see
tables 2 and 3). Such a fall can be due to failure of the hydraulic system, mechanical failure or a failure of the
electrical control system. The risk shall be prevented by either:
– a mechanical restraint device;
– a hydraulic restraint device (see 5.2.1.2);
– a combination of a single valve hydraulic restraint device and a mechanical restraint device.
The restraint device(s) shall operate automatically and shall be effective whenever the tool (i.e. punch) is
stopped and operator access to the tools area is possible.
5.2.1.2 Where mechanical restraint is not used and the risk of injury from a gravity fall exists, the hydraulic
restraint devices shall consist either of:
a) two separate hold–up or return cylinders each with a hydraulic restraint device capable of independently
holding the beam, or
Page 13
b) two hydraulic restraint valves fitted to the cylinder outlet using flanged, flared or welded pipework,
capable of holding the beam. Compression fittings and glued rings shall not be permitted (see 5.2.2.7
and figure C.1).
c) the piping between the cylinder and the first restraint valve shall be seamless.
5.2.1.3
On a press brake designed solely for:
– automatic operation;
– use with fixed enclosing guards;
– use with a hold-to-run control device used in conjunction with slow closing speed (see 5.3.15);
a single valve hydraulic restraint device or a mechanical restraint device, shall be provided as a minimum.
5.2.1.4
There shall be a system for automatically checking that the restraint system as defined in 5.2.1.1 is
functioning correctly and no press brake stroke shall be possible after any of the systems has failed (see figure
C.1 and 5.4.1.3).
NOTE:
See also 5.4.1.2 and 5.4.1.3 on the control system requirements to prevent unintended strokes.
5.2.2 Hydraulic and subsidiary pneumatic systems - Common features
5.2.2.1 The requirements in EN 982 and EN 983 shall be taken into consideration in designing hydraulic and
pneumatic systems, which shall comply with the particular requirements in 5.2.2 and 5.2.3.
5.2.2.2 Filters and pressure regulators shall be provided.
5.2.2.3 The design shall ensure that the working pressure is maintained within the permitted range.
5.2.2.4 Pressurized transparent bowls (e.g. glass, plastic) shall be protected to prevent injury from flying
particles, without affecting visibility.
5.2.2.5 All piping, pipe fittings, passages, surge or storage tanks and cored or drilled holes, shall be free from
burrs or foreign matter which can cause damage to or failure of the system (see 5.3.4.2.3 of EN 982:1996 and
5.3.4.2.3 of EN 983:1996).
5.2.2.6 Each run of piping shall, where practicable, be continuous from one piece of apparatus to another.
Precautions shall be taken (e.g. avoidance of straight rigid piping between connection joints) to prevent
damage by thermal expansion. Rigid piping shall be supported at frequent intervals to avoid damage from
movement. Kinking of flexible piping shall be avoided.
5.2.2.7 Where a drop in pressure can lead to unexpected hazardous motion of the beam, flexible piping shall
not be used; piping and pipe connections shall be chosen to prevent such a loss of pressure. Such pipe
connections shall not be made with compression fittings, glued rings or similar devices. They shall be made by
means of positive connecting joints, or by the welding of two fitted surfaces. See also 5.2.1.2.
5.2.2.8 Operating valves shall not depend on connected piping for support.
5.2.2.9 Control valves and other control components (e.g. regulators, pressure gauges) shall be mounted in
positions which provide accessibility and protection against damage.
5.2.2.10 Where valves are manually or mechanically (as distinct from electrically) operated, the arrangements
for restoring the valves shall be positive (i.e. when the actuator of the valve is released, the valve shall
automatically move to the safe position). See also 5.4.6.
NOTE: The safe position can be the open or closed position of a valve, depending upon the well-tried
principles in the hydraulic or pneumatic circuit.
5.2.3 Hydraulic systems
5.2.3.1 Controlled gravity descent can be a deliberate design feature to facilitate rapid closing of the tools. In
such a case, all the oil in the cylinder supporting the beam shall be passed through the main control valve or
valves in a redundant and monitored system (R & M in tables 2 and 3).
5.2.3.2 Hydraulic systems which include accumulators shall allow the fluid pressure to fall when the pressure
generating unit is disconnected from the energy supply; the stored energy shall not allow the initiation of any
hazardous movement. If this is impossible, the parts of the circuit which are maintained under pressure shall
be supplied with a manual discharge valve in addition to the other devices (e.g. relief valves, pneumatic
gauges) required by standards or rules concerning accumulators and bear a very clear indication (by means of
a descriptive plate) of the hazard (see 5.3.4.5 of EN 982:1996).
5.2.3.3
The circuit shall be protected by a pressure limiting valve(s). These valves shall not be capable of
alteration without the use of a tool; also they shall be set at a pressure which is no more than 10% higher than
the maximum operating pressure.

Page 14
5.2.3.4 For downstroking press brakes, provision shall be made to protect the cylinder and components
containing the fluid in the lower part of the cylinder from damage due to pressure intensification. A relief
valve(s) used for this purpose shall be direct operated, sealed and locked against unauthorised adjustment,
and shall be set at a pressure at least 10% above the maximum system pressure so that it only opens in the
case of a fault. The components it protects shall be designed to sustain the pressure at which the valve is set.
The relief valve shall be constructed so that, if a single break in the spring occurs, the space between the
windings remains less than one wire thickness. The spring shall be guided so as to maintain the function of the
relief valve.
5.2.4 Electrical systems
The electrical equipment of the machine shall comply with EN 60204–1:1997, together with the following:
5.2.4.1 The designer of a press brake should consider whether the limits of the power supply, the physical
environment as well as the operating conditions of some components are different than 4.3 and 4.4 of
EN 60204–1:1997. In this case, the choice of relevant components has to be made in this respect.
5.2.4.2
The emergency stop shall function as a category 0 stop (see 9.2.5.4 of EN 60204–1:1997 and
5.4.5.2) The emergency stop shall stop all hazardous movements (e.g. beam, back gauges, supports, integral
handling devices).
5.2.4.3 Two–hand control devices shall conform to 5.5.6 for tool–setting, maintenance and lubrication.
5.2.4.4 The minimum degree of protection for operator interface and press–mounted control devices shall
be of at least IP 54 (see EN 60529:1991).
5.2.4.5 Enclosures of controlgear shall provide a degree of protection of at least IP 54 (see
EN 60529:1991).
5.2.4.6
The identification of conductors other than the neutral or protective bonding conductors shall be in
accordance with choices mentioned in 14.2.4 of EN 60204–1:1997.
5.2.4.7
The interfacing between hold-to-run control devices, inching devices and the operative parts of the
control system shall not rely solely on one relay. A short–circuit in the wiring shall not result in an unexpected
start–up.
5.3 Mechanical hazards in the tools and associated areas
5.3.1 The major danger zone at hydraulic press brakes is the tools and associated areas and preventive
measures shall be taken to deal with the relevant hazards. This standard indicates in 5.3 to 5.5 how the
danger zone at the tools and associated areas, such as moving sheet supports, moving gauges and deflecting
workpieces, shall be safeguarded. Tables 2 and 3 give the summary of the requirements for safeguarding of
the tools and associated areas.
5.3.2
Safeguarding measures described in parts 1 and 2 of EN 292 which are appropriate for the protection
of any operator at the tools are listed below. Designers, manufacturers and suppliers shall select the
safeguarding methods which reduce the risks as far as possible, considering the significant hazards (see
table 1) and the mode of production (see tables 2 and 3):
a) closed tools (see EN 294, EN 349 and 5.3.6), but note the restriction in 5.3.4;
b) fixed enclosing guards (see EN 294, EN 953 and 5.3.7), but note the restriction in 5.3.4;
c) interlocking guards with or without guard locking (see EN 953, EN 1088, 5.3.8, 5.3.9, 5.3.10 and 5.3.13);
d) control guards with or without guard locking (see 4.2.2.5 of EN 292-2:1991/A1:1995, EN 953, EN 1088,
5.3.8, 5.3.9, 5.3.11 and 5.3.13);
e) early opening interlocking guards with or without guard locking (see EN 953, EN 999, EN 1088, 5.3.8,
5.3.9, 5.3.10 and 5.3.13);
f) electro-sensitive protective equipment (ESPE) using active opto-electronic protective devices (AOPDs)
in the form of light curtains (see EN 999, EN 61496-1, prEN 61496-2:1997, 5.3.12.1, 5.3.12.2 and
5.3.13);
g) hold-to-run control devices (see 3.23.3 of EN 292-1:1991) used in conjunction with a slow closing speed
- less than or equal to 10 mm/s - (see 5.3.14).
5.3.3
The selected combination of safeguarding methods shall protect all exposed persons, (i.e. those who
can gain access to the danger zone during operation, setting, maintenance, cleaning and inspection activities),
as described in 4.2.
5.3.4 Where a press brake is capable of being manually loaded and/or unloaded, the safeguarding system
shall not rely solely on the use of closed tools or fixed enclosing guards; it shall always be supplied with one or
more of the safeguarding systems listed in 5.3.2 c) to h).
Exception: Press brakes intended to work solely in automatic cycle with automatic loading and unloading may
be designed only for the use of closed tools or fixed enclosing guards.

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Where a press brake which allows manual loading and/or unloading is supplied with one or more of the
safeguarding systems listed in 5.3.2 c) to h), it shall not be possible to operate the press brake at speeds in
excess of 10 mm/s with the safety system(s) disconnected.
5.3.5 The provided guards and protective devices shall be at least interfaced with the control system of the
press brake in the same category as required for these guards and devices.
5.3.6 Closed tools shall be inherently safe. Openings and the corresponding distances shall meet the
requirements laid down in table 4 of EN 294:1992. Any additional crushing hazard shall be avoided following
table 1 of EN 349:1993. (See also 5.3.4)
5.3.7 Fixed enclosing guards shall comply with EN 953. They shall be firmly secured to the machine,
another rigid structure or the floor (see also 5.3.4).
5.3.8 Interlocking guards and control guards shall comply with EN 953 and prevent, in conjunction with fixed
guards, access to the danger zone in the tools area during any hazardous movement. Initiation of the stroke
shall be prevented until the guard gate is closed. The associated interlocking devices shall be designed and
constructed in accordance with 6.2.2 of EN 1088:1995, and the associated control system shall conform to
category 4 of EN 954-1:1996.
5.3.9
The guards mentioned in 5.3.8 shall be provided
a) either with guard locking, to prevent the opening of the guard gate until any hazardous movement in
the tools area has ceased;
b) or without guard locking, but designed to bring the hazardous movement to a stop before the danger
zone can be reached.
5.3.10 Where an interlocking guard or a control guard has an early opening feature, it shall function as an
early opening interlocking guard (see 3.1.7).
5.3.11
Using an interlocking guard as a control guard, it shall not be possible to stand between the guard and
the danger zone. This can be prevented using additional safeguarding means. These additional safeguarding
means shall either be an AOPD (type 4) or a fixed guard kept in place permanently (e.g. by welding) or an
interlocking guard in accordance with clause 6.2.1 of EN 1088:1995.
Control guard(s) shall be securely held open (e.g. by spring or counterweight) to avoid gravity fall which can
cause unintended cycle initiation.
5.3.12 ESPE using AOPDs in the form of light curtains
5.3.12.1 ESPE using AOPDs in the form of light curtains shall comply with the following:
a) light curtains and light beams shall conform to type 4 in accordance with 4.2.2.5 of EN 61496-1:1997,
and be designed and constructed according to prEN 61496-2:1997;
b) access to the danger zone shall only be possible through the detection zone of the light curtain.
,
Additional safeguarding shall prevent access to the danger zone from any other direction but see 5.3.22
and 5.3.23;
c) additional safeguarding shall be provided to ensure that no hazardous movement is possible standing in
position between the light curtain and the danger zone of the press brake; this gap shall not exceed
75mm; but see 5.3.12.2 a) and b);
d) it shall not be possible to initiate any hazardous movement while any part of the body is interrupting the
light curtain;
e) the means of resetting shall be so positioned that, from that position, there is a clear view of the danger
zone. There shall not be more than one reset control device on each detection zone. If the press brake
is safeguarded by means of side and back AOPDs, a reset control device shall be provided on each
detection zone;
f) Blanking may only be incorporated into the AOPD as long as the safety distance is such as to ensure
that it is not possible to reach the danger zone (see table A.1 of annex A). It shall not be possible for the
user to increase the blanking range.
g) where the light curtain operates by reflecting the transmitted light beam back along its own path and
additional reflector(s) are placed within the detection zone, then the configuration of the additional
reflector(s) shall not allow an item of thickness equal to or greater than the specified test piece size (see
4.1.2 of prEN 61496-2:1997) to be undetected by the light curtain within the whole of the detection zone,
unless other measures are taken to ensure that it is not possible to reach the danger zone;
h) where the light curtain is also used for cycle initiation, either single or double break:
i) the detection capability shall not exceed 30 mm (see also annex A);
ii) if, in front of the press brake, additional guards are used, they shall either be fixed guards kept in
place permanently (e.g. by welding), or interlocking guards (see also b)). With parts of the body in
the danger zone (e.g. fingers), it shall not be possible to free the light curtain for cycle initiation (see
annex A);
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iii) Before the first cycle initiation, the reset function(s) shall be manually actuated (e.g. push button,
foot pedal).
iv) The facility to initiate the press brake motion upon clearing of the curtain shall be limited to the pre-
set time. This pre-set time shall not be capable of exceeding 30 s starting from the end of the
previous operating cycle. The AOPD shall be required to be manually reset, if the pre-set time has
been exceeded.
v) if there is more than one light curtain safeguarding the press brake, only one of them at the front
shall be selected for cycle initiation at any one time.
i) switching off the light curtain by the selector switch shall also switch off the indicator lights.
5.3.12.2
Size and positioning of light curtains
Light curtains can be positioned in the following configurations:
– vertical format (see a) below)
– horizontal format (see b) below)
– angled format (see c) below)
– a combination of formats (see d) below).
For upstroking press brakes, the position of the bed is measured at its lowest point.
a) vertical format light curtains shall be configured as shown in figure 2. The minimum effective vertical
height of the light curtain shall be 800 mm, where the height of the bed a is 850 mm or more. If the height of
the bed is below 850 mm, the light curtain will need to increase in length accordingly. The minimum vertical
overlapping distance b between the bed and the bottom edge of the light curtain shall be at least 50 mm (see
figure 2).
c
The minimum height of the top edge of the light curtain shall be 1600 mm above the reference plane. The
minmum height c = 1600 mm or the minimum height of the detection zone 800 mm of the light curtain may be
reduced only if additional safeguarding prevents any access to the danger zone.
The light curtain object detection capability shall be 14 mm or less if no additional distance, C, is used to
achieve the required safety distance (see annex A).
The minimum safety distance, d, shall be calculated according to the formula in annex A, but shall never be
less than 100 mm.
Where the vertical format light curtain cannot be placed against the press brake frame, then the resulting gap
shall be guarded by
- either fixed or interlocking guards,
- or additional light beams.
The gap between bars in a fixed guard, or between the frame and the edge of the fixed or interlocking guard or
single light beam shall follow the minimum distances set out in EN 294.

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Key 1 : sheet support
a – height of the bed;
2 : Additinnal light beam(s)/guard(s)
b – overlapping distance;
c – height of top edge of the light curtain;
3 :Max. distance (see text) reference plan
d – safety distance.
Figure 2 - Configuration of the vertical format light curtain
(side and rear guards omitted for the purpose of this figure)
b) Horizontal format light curtains shall be configured as shown in figure 3, when the height of the bed, a, is
b
not less than 800 mm or more than 1200 mm. The minimum overlapping distance between the bed
and the bottom edge of the light curtain shall be 50 mm.

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Key 1 : sheet support
a – height of the bed;
2 : Max. distance (see text)
b – overlapping distance;
3 : possible alternance position of light curtain
c – height of the light curtain;
4 : Reference plan
d – safety distance.
Figure 3 - Configuration of the horizontal format light curtain
(side and rear guards omitted for the purpose of this figure)
Where the overall response time is 200 ms or less, the minimum safety distance d shall be at least
1000 mm. Where the overall response time exceeds 200 ms, 20 mm shall be added to the figure of
1000 mm for each additional 10 ms.
The detection capability shall be 40 mm or l
...