Rope Pull Safety Switches Accessories
The new accessories, in comparison with the traditional fixing system through carpentry material, have the following advantages:
- The installation is faster because only one screw is used for the fastening of every rope extremity, and the parts are prepared to ease the installation. Some practical tests have pointed out that the installation time is halved, reason for which it is named FAST.
- The system is aesthetically pleasant, because thread parts (which sometimes tear operators’ dresses) and the rope extremities, usually fixed by heat-shrinkable sheath or adhesive tape, have been hidden.
- The red plastic covers of the fixing parts have been developed also for the function of controlling the rope clamping. If the rope fastening screw is not fixed tightly enough, the cover cannot pass.
- The rope is fixed without folds, thus reducing the rope stabilization time and the possible recalibrations of the rope tightening.
- The system has been tested for correct function only if used with steel ropes of high quality like the ones Pizzato Elettrica usually supplies.
Safety springs
Some rope safety switch applications require ropes with particularly long rope lengths. With day/night changes of temperature, the ropes are lengthened or shortened in proportion to the rope length, to the change of temperature and to the coefficient of expansion of the steel. The changes of the rope length do not have linear repercussions on the switch, because the very long ropes are regularly sustained by supports that modify the linearity of the system. As the safety switches have to be installed stretching the rope inside the working area of the switch, it is possible that for particularly long ropes or particularly high changes of temperature there will be the unwanted activation of the switch. To reduce the effect of the changes of the temperature, it is possible to install a safety spring at the opposite extremity of the switch, so the rope elongation is equally divided between the two devices. The safety spring has been made to have an elastic coeffi cient equal to the spring inside the switch. The safety spring has also a stop ring that, in case of emergency actuation, let the rope traction to work only on the switch.
Pulleys for rope
The pulleys are used in applications where the rope is too long, to support its length or bend its route. Two sturdy pulleys designed to avoid the deformation and allow the rope to remain in its seat also when it’s activated energetically, have been made. The angular pulley has been designed with a particular shape and with a slotted fixing hole to make the installation easier and to maintain the rope to a correct distance from guards edges.
Safety Modules
The rope safety switches and the mushroom-head push buttons inserted in the emergency chains can be connected with the Pizzato Elettrica safety modules in order to obtain safety circuits up to category 4 in accordance with EN 954-1. Safety modules with instantaneous and delayed contacts are available for the realization of emergency circuits type 0 (immediate stop) or type 1 (monitored stop).
Light indicators
Sometimes it is useful to have a visible local signal to identify when or which rope switch has been actuated. The Pizzato Elettrica signal lamps have been created for this requirement, and they have been designed to be directly fixed on the threaded entries of the switches. These light indicators are sturdy, have IP67 protection degree and accept any BA9 electric bulb connection with power up to 3 W. The lamps are divisible into two parts for substitution of the electric bulb without removing the lamp holder, and their internal part can rotate without the risk of kinking the cables. Three different semitransparent color covers are available. The possibility to have rope switches with 3 pole contacts allows the making of circuits where each switch has two NC contacts with positive opening for the safety chain, and one NO contact for the light indicator.
Function indicator for rope
These function indicators help in the visualization of the rope and its emergency function highlighting its presence as recommended by the standard EN 418 chap. 4.5.1. They are fixed on the rope through screws and thanks to their handle-shape make the operation easier. The indicators can be supplied with different texts in several languages.