BS 1870-5:2002 pdf download – Safety of woodworking machines — Circular sawing machines — Part 5: Circular sawbenches/up-cutting cross-cut sawing machines 5 Safety requirements and/or measures For guidance in connection with risk reduction by design, see clause 3 of EN 292-2:1991/A1:1995, and in addition :5.1 Controls 5.1.1 Safety and reliability of control systems For the purposes of this European Standard a safety related control system is one from and including the initialmanual control or position detector to the point of input to the final actuator or element e.g.motor. The safetyrelated control systems of this machine (see EN 954-1:1996) are those for : starting (see 5.1.3); normal stopping (see 5.1.4); interlocking (see 5.2.7.3,5.2.7.4);the braking system (see 5.1.4,5.2.4). These control systems shall， as a minimum be designed and constructed using “well tried components andprinciples”. For the purposes of this European Standard “well tried components and principles” means : a) electrical components if they comply with relevant standards including the following as : i)EN 60947-5-1:1997, section 3 for control switches with positive opening operation used as mechanicalactuated position detectors for interlocking guards and for relays used in auxiliary circuits; ii) EN 60947-4-1 for electromechanical contactors and motor-starters used in main circuits; ii) HD 22.1 S3 for rubber-insulated cables; iv)HD 21.1 S3 for polyvinyl chloride cable if this cable is additionally protected against mechanicaldamage by positioning (e.g. inside frames). b) electrical principles if they comply with the first four measures listed in 9.4.2.1 of EN 60204-1:1992.Thecircuits shall be either “hardwired”, or if electronic components are used in safety related control systems “weltried” is fulilled if they are in accordance with 9.4.2.2 (i.e. redundancy with cross-monitoring) or 9.4.2.3(i.e.diversity) of EN 60204-1:1992; c) mechanical components if, for example，they operate in the positive mode in accordance with thedescription given in 3.5 of EN 292-2:1991/A1:1995; d)mechanically actuated position detectors for guards if they are actuated in the positive mode and theirarrangementfastening and cam design/mounting comply with the requirements of 5.2 and 5.3 of EN1088:1995. Time delay devices used in hardwired safety related control circuits can be of category B in accordance with therequirements of EN 954-1:1996 if the time delay device is designed for at least one million actuations. Verification : By checking the relevant drawings andor circuit diagrams and inspection of the machine, for electricalcomponents by requiring confirmation from the manufacturer of the component which declares conformity with therelevant standards. 5.1.2Position of controls The start control and...
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