Miniature load pins

Apart from regular load pins in our standard or custom-made product range with the classic pin diameter of between 15 and 450mm (or more) for hoisting systems, mooring winches, test benches and others, new applications, mainly in the aerospace industry for qualification test purpose or on-board controls, require more and more compact instrumented pins, with tiny diameters and very short operating lengths.

These have an operating diameter ranging from 7 to 10mm and lengths around 15-20mm. Bear in mind that the main limit in terms of compact design is the size of strain gauges available, which makes it difficult to go below 7mm diameter. The permissible thickness of the plates holding the pin and the span of the central tool are also limited for the same reasons – i.e. the size of the strain gauges.

For such diameters and lengths, it is obvious that only external bonding is workable (pocket covers visible). Internal bonding is simply impossible because tiny diameters do not even allow for the bores meant for the wires from the strain gauges to the compensation circuit installed in the connection box or the pin, which has a larger diameter to allow installing the above-mentioned temperature compensation circuit and analogue (0-10V, 4-20mA) or digital (RS485, Modbus, CAN) amplifier if required, as well as the connector or cable gland for cable entry.

Compact dimensions and impact on the bonding method and IP protection also imply limitations on possible ingress protection. The smallest diameters will be limited to IP65, depending on their length; others could be IP67. However, we will not be able to determine if this is workable before the design stage.

A miniature load pin also means low nominal capacity! We can manufacture this type of pin with classic safety coefficients: 150% permissible overload for 300% breaking load, 200% / 500% and 400% / 1000%; but for the same dimensions, the nominal capacity will be lower according to the safety factors required for the application concerned.