The TAIL capacity limiter is a safety device applied to wire rope lifting equipment to prevent the operator lifting loads in excess of those for which the machine was designed.
The capacity limiter is attached directly to the end of a fixed rope. The application procedure is simple and does not require the disassembly of any of the mechanical parts mounted on the lifting winch.
Following the application, the axe of rope concerned is slightly off-line in relation to the normal lifting path.
These produces a small angle which tends do disappear as the load increases.
The angle is proportional to the capacity; the tie rod, which is clamped to the rope, is thus made to move axially, impeding the action of a cup - type spring and acting upon a micro switch, thereby opening a contact.
By setting the operation point of the micro switch at a certain limit and carrying out some appropriate adjustments it is possible to obtain a warning light or claxon, an interruption in the lifting movement, or the operation of some indicators.
Setting the device is a simple operation, carried out by turning a screw. However, if the device is to be used on relatively high speeds or accelerations, dynamic forces (approximately 15%) must be taken into account.
The general rule is to attach the limiter to the lowest lifting speed movement, thus obtaining more realistic values and closer tolerances.
It must also be remembered that testing is carried out in overload (usually 10 25% extra load) conditions. Alternatively contacts can be temporarily bypassed during testing.
The micro switch is provided with a normally closed contact which opens slowly when the set load is exceeded.
Maximum intensity of current 6A
Maximum voltage 250V
-30C ÷ + 80C
Life 10 million operations
Execution IP 55
On request the TAIL can be supplied with a microswitch with two contacts, one of which is open and one is fast acting.
Cup-type springs, carefully selected and individually tested.
Tie-rods in tough, high tensile, chrome-nickel alloy steel, sliding in a bush in self-lubricating material.
Microswitch housing in die-cast aluminium with seals.
Counteracting wheels in steel alloy with self-lubricating bushes or in hard, solid bronze.
MECHANICAL APPLICATION AND SETTING OF THE LOAD LIMITER
The limiters are supplied without any particular setting. From a pratical point of view the actual setting on board the machine involves the selection of the exact tripping point of the micro switch, which in turn acts upon the lifting contactor (or on an auxiliary contactor with the same function or to set off a warning light or alarm signal)
|Esecuzione normale o antideflagrante||(Pmin
|Temperatura ambiente||-40°C/ +55°C|
|TIPO||A||B||C||D||E||G max||P max