The Load Guard is intended for use as an overload guard in cranes and lifts, for the automatic tensionsing of belt conveyors and for other eutomatic power-sensing or load control.
For process control, overload alarm, stepped moment protection and load sensing systems. The instruments have a high repeating accuracy and fully conform to the International Protection Specification Class IP 67.
The movement of the pull rod operates the micro switches through spring loaded contact points. The power absorbing element consists of specially made Belleville wasers dimensioned to resist fatigue. The spring washers cannot be overloaded.
The safety factor is 5:1 which gives guaranteed strength against breakage at least 5 times the maximum capacity. The Load Guard can be overloaded by 100% without inter fering with the switch setting. As the transmission parts between the pull rod and the micro switch are spring loaded, the Load Guard can withstand severe shock loads and sudden unloading. The pull rod and upper bracket of hte load guards types IMB-IG are made of drop forged steel SIS 2174 (St 52-3N acc. to DIN 17100, 50 D acc. to BS 4360) which has guaranteed impact strength down to -20°C.
The Load Guard with one or two micro switches is supplied with alternative contact connections for each micro switch. Load Guards with three, four or five micro switches have either one breaking or closing function on each switch. These are normally set for the breaking function, i.e. closed contacts at rest, and for rising loads, unless otherwise ordered. When set for falling load, e.g. control on the slack line, the micro switch is connected for the closing function, i.e. open contact at rest