1 Presses are machines used in shaping and cutting of various materials, in which slide motion – puncture – is made by a hydraulic or pneumatic system – hydraulic or pneumatic cylinder, or a mechanical system, wherein the rotational movement is transformed into linear movement through a system of connecting rods, cranks, set of levers or spindles.
1.1 Presses are divided into:
a) eccentric mechanical coupled by key or equivalent coupling
b) eccentric mechanical with brake or clutch;
c) spindle driven friction;
d) servo actuated;
e) hydraulic;
f) pneumatic;
g) hydropneumatic; and
h) other types not listed in this sub-item.
1.2 Similar machines are those with functions and risks equivalent to the presses, comprising:
a) drop hammers;
b) pneumatic hammers;
c) hammers;
d) press brakes;
e) depressors;
f) guillotines, scissors and shears;
g) compression and moulding presses;
h) hydraulic and pneumatic devices;
i) straighteners;
j) baling presses; e
k) other similar machines not listed in this sub-item.
1.2.1 The provisions of this Annex do not apply to the machines called swing arm cutting machine and die cutting machine, which shall meet the requirements of Annex 10 of NR12.
1.3 Tools – tooling, stamps or dies are elements fixed on the hammer and on the table of presses and the like, with the function of cutting or forming materials, and can incorporate feeding or extracting systems listed in sub-item 1.4.
1.4 Feeding or extracting systems are means used to introduce raw materials and remove the processed workpieces from the die, and can be:
a) manual;
b) by drawer;
c) by rotating tray or revolving drum;
d) by gravity, regardless of the means of extraction;
e) by mechanical hand;
f) by conveyor or robotics;
g) continuous – automatic feeders; and
h) other systems not listed in this sub-item.
2. Safety systems in point of operation
2.1 Acceptable safety systems in point of operation:
a) enclosing the point of operation, so that openings shall not allow fingers and hands entering the danger zone, in accordance with item A of Annex I of NR12, and can consist of fixed or interlocked moveable guards, according to items 12.38 to 12.55 and their sub-items of NR12;
b) enclosed tool, which means the enclosement of a pair of tools, so that openings shall not allow fingers and hands entering the danger zone, according to Table I, item A of Annex I of NR12;
c) light curtain with redundancy and self-test, monitored by safety interface properly sized and installed in accordance with item B of Annex I of NR12 and current official technical standards, combined with two-hand control, observing the provisions of items 12.26, 12.27, 12.28 and 12.29 of NR12.
2.1.1 If there is a possibility of access to the danger zones not supervised by the light curtains, there shall be fixed or interlocked moveable guards, according to the items 12.38 to 12.55 and their sub-items of NR12.
2.1.2 The number of two-hand controls shall match the number of operators on the machine, according to item 12.30 and its sub-items of NR12.
2.1.3 The safety systems mentioned in paragraph “c” of subitem 2.1 and in item 2.1.1 of this Annex shall be classified as category 4, according to NBR 14153.
3 Protection of point of operation.
3.1 The eccentric mechanical presses, which are coupled by key or equivalent coupling system of full stroke with actuation by spindle and like, cannot allow hands or fingers entering the points of operation and shall adopt the following safety systems:
a) enclosure with fixed guards and, if it is necessary to change tools frequently, with interlocked moveable guards, so as to allow an opening only after the slide completes its dangerous movement, according to paragraph “a” of sub*item 2.1 of this Annex and item 12.46 of NR12; or
b) operation only with closed tools, according to paragraph “b” of sub-item 2.1 of this Annex.
3.2 The eccentric mechanical presses with break and clutch, servo-powered, hydraulic, pneumatic, hydropneumatic and similar presses shall meet the following safety systems:
a) enclosure with fixed guards or interlocked moveable guards, according to paragraph “a” of sub-item 2.1 of this Annex; or
b) operation only with closed tools, according to paragraph “b” of sub-item 2.1 of this Annex; or
c) use of light curtain combined with two-hand control, according to paragraph “c” of sub-item 2.1 and its sub-items of this Annex.
4 Hydrolic and pneumatic control systems.
4.1 The eccentric mechanical presses with pneumatic break or clutch, the pneumatic presses and similar presses shall be controlled with specific safety valves with cross-flow, dynamic monitoring and residual pressure relief.
4.1.1 The press and the like shall have a manual reset, incorporated in the safety valve or in other component of the system, so as to prevent actuation in case of failure.
4.1.2 Monitoring shall be performed by safety interface, in specific valve models with external dynamic monitoring through pressure switch, micro-switch or proximity sensors.
4.1.3 Exhaust silencers that do not pose risk of clogging, or have free passage corresponding to the nominal diameter can only be used, so as not to interfere with stopping time.
4.1.4 When independent safety valves are used to control the presses and the like with separated brake and clutch, they shall be interconnected so as to establish a dynamic monitoring between themselves, in order to ensure the brake is immediately applied when the clutch is released during the cycle, and also to prevent the clutch engagement if the brake valve does not work.
4.1.5 Compressed air supply systems for pneumatic presses shall ensure the effectiveness of safety valves, and have air vents or air drying system and automatic lubrication system with specific oil for this purpose.
4.1.6 The requirement in sub-item 4.1.4 does not apply to pneumatic presses and the like.
4.2 The eccentric mechanical presses with hydraulic break or clutch and the similar shall be controlled with safety systems consisting of redundant valves with dynamic monitoring.
4.2.1 The press and the like shall have a manual reset, so as to prevent actuation in case of failure.
4.2.2 Monitoring shall be performed by safety interface, in valve systems with external dynamic monitoring through pressure switch, micro-switch or proximity sensors.
4.2.3 When independent valves are used, they shall be interconnected so as to establish a dynamic monitoring, ensuring that there is no residual pressure that can negatively affect the operation of the brake and clutch in case of failure of one of the valves.
4.2.4 When independent valves are used to control the presses and the like with separated break and clutch, the provisions of sub-item 4.1.4 shall be applied.
4.3 The hydraulic presses and the like shall have a hydraulic blocking system consisting of redundant valves that have the same characteristics and efficiency, with dynamic monitoring.
4.3.1 The press and the like shall have a manual reset, so as to prevent actuation in case of failure.
4.3.2 Monitoring shall be performed by safety interface, in valve systems with external dynamic monitoring through pressure switch, micro-switch or proximity sensors.
4.3.3 When independent valves are used, they shall be interconnected so as to establish a dynamic monitoring, ensuring that there is no residual pressure that can compromise the safety in case of failure of one of the valves.
4.3.4 The hydraulic presses and the like shall have a retention valve or system to prevent the fall of hammer in case of failure in safety block or hydraulic system.
4.3.5 When hydraulic system is used, the retention valve or system shall be located as close as possible to the cylinder.
5 Emergency stop devices.
5.1 The presses and the like shall have emergency stop devices that ensures the safe stop of machine or equipment, according to items 12.56 to 12.63 and their sub-items of NR12.
5.2 The emergency stop system shall be interconnected with emergency stop systems of equipments such as unwinders, straighteners and feeders, so that activating an emergency stop device of any equipment causes immediate stop of all others.
5.3 When connectable or removable two-hand control devices, which contain emergency stop button, are used, there shall also have emergency stop device on panel or body of the machine.
5.4 If there are several two-hand controls, they shall be connected so as to ensure proper functioning of emergency stop buttons from each of them, in accordance with NR12.
6 Monitoring of hammer position.
6.1 In eccentric mechanical presses with break or clutch, with no enclosed pressing area, or whose tools are not closed, the hammer position shall be monitored by electrical signals produced by equipment mechanically coupled to the crankshaft.
6.1.1 The monitoring of hammer position, comprised of bottom dead center – BDC, top dead center – TDC and maximum permissible slide, shall include devices to ensure that if the braking slide exceeds the maximum permissible slide specified by ABNT NBR 13930, a stop action shall be immediately initiated and starting a new cycle cannot be possible.
6.1.2 The electrical signals shall be generated by safety switches with dual channel and positive break, monitored by safety interface classified as category 4 according to ABNT NBR 14153.
6.1.3 When programmable safety interface that has programming blocks dedicated to control and supervisor function of TDC, BDC and sliding, the requirement of dual channel shall be waived.
6.2 In hydraulic, pneumatic and similar presses, with no enclosed pressing area, or whose tools are not closed, the position of hammer shall be monitored.
6.3 For presses which it is not possible to ensure the safe stopping of hammer due to speed and response time of machine, use of light curtain to protect the point of operation is not permitted, exempting the provisions of sub-item 6.1 of this Annex, and the point of operation shall be protected fixed guards or interlocked moveable guards, according to items 12.38 to 12.55 and their sub-items of NR12.
7 Foot pedals.
7.1 The presses and the like that have enclosed point of operation or use only closed tools can be operated by pedals with electrical, pneumatic or hydraulic actuation. The use of pedals with levers or mechanical actuation is prohibited.
7.2 Foot pedal shall allow the access only by a single direction and by one foot, and shall be protected to prevent accidental activation.
7.3 For warm and hot forging activities the pedals can be used as provided in sub-item 7.2 of this Annex, provided that protective measures are taken to ensure the separation of workers from danger zones.
7.4 Foot pedals can be used in operation with press brakes as provided in sub-item 7.2 of this Annex, without the requirement of enclosuring the point of operation, provided that appropriate protective measures are taken against existing risks.
7.5 The number of pedals shall match the number of operators, according to item 12.30 and its sub*items of NR12.
8 Warm and hot forging activities
8.1 For warm and hot forging activities tweezers and pincers can be used, provided that protective measures are taken to ensure the separation of workers from danger zones.
8.1.1 If necessary, tweezers and pincers shall be supported by weight-relief devices, such as moveable rockers or tripods, so as to minimize work overload.
9 Protection of power transmissions.
9.1 Power transmissions, such as flywheels, pulleys, belts and gears shall be protected according to the items 12.38 to 12.55 and sub-items of NR12.
9.1.1 In eccentric mechanical presses there shall have fixed guards for connecting rods and the tips of their axes, which are resistant to related stresses in case of a breakup.
9.1.2 Vertical and horizontal flywheel of spindle-drive friction presses shall be protected, so that they are not hurled in case of breakup.
10 Tools.
10.1 The tools shall:
a) be built as to prevent the projection of material on the operators;
b) be stored in proper and safe locations;
c) be attached to the machines properly, with no improvisation;and
d) not pose additional risks.
11 Mechanical restraint systems.
11.1 The presses and the like shall have mechanical restraint systems that support the weight of the hammer and the top of the tool to lock the hammer at the start of the changes, adjustments and maintenance of tools.
11.2 The components of mechanical restraint shall be painted in yellow and have interlocking monitored by safety interface in order to prevent the operation of press during their use.
11.3 The components of mechanical restraint system shall:
a) ensure mechanical retention at several stop positions of the hammer; and
b) be designed and constructed to ensure resistance to static load exerted by the total weight of the mobile set to be sustained and to prevent its projection or easy release.
11.4 In situations where the use of mechanical restraint system is not possible, alternative measures shall be adopted to ensure the same result.
12 Similar specific machines.
12.1 In pneumatic hammers:
a) centeral shock absorver bolt shall be secured with steel wire rope;
b) air intake hose shall have protection that prevents its projection in case of rupture; and
c) all stud, top and bottom, shall be secured with steel wire rope.
12.2 The guillotines, scissors and shears shall have fixed guards, and if frequent intervention is required, shall have interlocked moveable guards to prevent hands and fingers entering the point of operation, according to items 12.38 to 12.55 and their sub-items of NR12.
13 Folders or Turning Presses.
13.1 The folding presses shall have safety systems that prevent accessing to danger zones from sides and rear of the machine, according to items 12.38 to 12.55 and their sub-items of NR12.
13.2 Folding presses shall have safety systems covering the work area, which are selected according to the characteristics of machine construction and the geometry of the piece to be shaped, meeting the followings:
a) foldering presses with mechanical brake or clutch, due to inaccuracy in determining the stopping time,can not have optoelectronic presence detectors for frontal protection of working area, and the operation by more than one operator and shaping of pieces that does not ensure the safe distance is prohibited.
b) folding presses with pneumatic brake or clutch and hydraulic presses can have optoelectronic presenc detectors for frontal protection of working area, if properly selected and installed according to item B of Annex I of NR12;
c) hydraulic folding presses can use multiple-beam laser optoelectronic presence detectors to protect working area in tasks with multiple folds, conditioned to the machine characteristics and limitations due to low speed availability, if equal or more than 10 mm/s, in the course of time that does not allow access of the worker ́s fingers, i.e. less than or equal to 6 mm;
d) in hydraulic folding presses endowed with multiple-beam laser optoelectronic presence detectors, complete deactivation – muting – shall occur only when the opening between upper tool and the piece to be shaped is less than or equal to 6 mm, associated with low speed movement;
e) multiple-beam laser optoelectronic presence detectors shall be installed and tested according to the recommendations of manufacturer, current specific technical standards and item C of Annex I of NR12; and
f) hydraulic folding presses that have multiple-beam laser optoelectronic presence detectors shall be activated by two-hand control devices provided in items 12.26, 12.27, 12.28 and 12.29 or 3-position safety pedal, according to item C of Annex I of NR12.
13.3 Folding presses operated solely by robots can be exempted from the requirements of sub-items 13.1 and 13.2 of this Annex, provided that they have perimeter access protection systems to prevent the workers being around the machine and robot, according to items 12.38 to 12.55 and their sub-items of NR12.
13.4 Additional measures, such as the use of positioners, tables or magnetized backrests, shall be adopted to prevent injury to the hands of workers between the work piece and the structure – apron – of the machine at the time of forming.
14 The winders, non-winders, straightener and other feeding equipment shall have protection around the perimeter, preventing access and the circulation of persons in risk areas, according to items 12.38 to 12.55 and sub-items of this Standard.
15 Other provisions
15.1 In exceptional cases, other protective measures and safety systems can be adopted, provided that they ensure the same effectiveness of the protections and devices mentioned in this Annex, and comply with the provisions of current official technical standards.
15.2 The importation, manufacture, marketing, sale, lease, cession of eccentric mechanical presses and the like with coupling to drop of hammer by coupling key or similar and mechanical folding presses with band brake, new or used, is prohibited under any title and exhibition throughout the national territory.
15.2.1 Those that do not allow the immediate stop of the slide motion in any position of the hammer are understood as similar mechanisms.
16 Modification of presses and similar equipments
16.1 Any substantial modification on operating system or coupling system for moving the hammer – “retrofitting” presses and similar equipments shall be performed only through mechanical design prepared by a legally qualified professional, accompanied by Annotation of Technical Responsibility – ART.
16.2 The design shall contain calculations of component dimensioning, specification of the materials used and the descriptive history of all components.
