Safety emergency stop device

The nip is the radial distance or V formed between rolls on a line of centers. In-going safety devices in the nip areas are built into these machines. They protect the hands of operators. An emergency stop device is placed in an accessible location on the upstream side. 

Detailed information is provided on safety procedures and safety devices for machine operations, including guards, doors, emergency stops, light curtains, safety bars, and hydraulic and compressed air safety. 

Are all safety devices functioning correctly, e.g. emergency stops, interlocks ... 

Hoist safety system—focused on safety critical functions only over speed, overwinds, and emergency stops. The system may also have a mechanical device that fulfils the function of speed and distance protection. 

Arrest of dangerous machine motion resnlting from actuation of an emergency stop switch. The switch may be in the form of a safety switch, bntton, trip cable, or foot bar or other mechanical device used in conjnnction with an emergency stop safety module. Emission Control... 

A trip device is any device which, as the operator approaches the dangerous part, automatically trips the safety circuit. A simple flap trip is shown in Figure 4.3.13 but trip devices can include trip bars and wires, sensitive probes (on drilling machines), photoelectric devices, pressure sensitive strips and mats, and emergency stop switches. Figure 4.3.14 shows a pull trip switch on a conveyor. It is important that trip devices are properly adjusted and that the machine s brake is in good working order. 

Other machine features that offer protection include moveable barriers, automatic feed systems, presence-sensing devices, emergency stop control, hand control devices and mechanisms, such as pull-out devices, restraint devices, and two-hand control. Reduced speed control is used during setup, cleaning, and maintenance. Other safety mechanisms include antikickback devices, run controls, and foot controls. 

Doors or gates which can be opened by either being pushed or pulled must have a clear view of both sides when closed Escalators and moving walkways must function safely, have any necessary safety devices and be fitted with one or more emergency stop controls. 

Whilst we are considering relay based systems its is important to be aware of the wide range of applications and devices in relays applied to machinery safety systems. In simple applications such as emergency stops and guard interlocks the safety integrity of the protection system depends very often on a single relay or a pair of relays and a pair of field contacts. 

Similarly there are established products in the automation sector using safety certified bus communications for safety devices such as emergency stops and light curtains with safety PLCs being added where needed. 

The Incident. Parts coming off the press were of good quality and the press was operating normally. To rearrange the stack of material to be cut and to spray water on it, which was done to eliminate static electricity, the operator stopped the press, by pushing the bottom safety bar at the platen location—what should have been a prohibitive practice except in an emergency. The circuitry did not require a resetting of the safety device to restart the press. 

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