BELOW THE HOOK
market. In some cases there may be minimum order quantities because the material is not stocked by steel mills and are created specially. This is getting into very specialised areas indeed. Cromox cater for more general lifting as well, offering stainless steel chain slings – for example 316 L for ATEX-proof , electro-polished against corrosion, round sling connectors for connecting round slings to a chain, and so on. “We have just completed a project in the US where we designed a lifting system for a furnace that is for heat treatment of aluminium cones for spacecraft.”
More than a one-trick pony Below-the-hook devices are not just for lifting. Load monitors are widely-used and, being mounted between hook and load, fit the definition. Load links replace part of the lifting rope: they work in tension. Strain gauges within them flex in line with the load, so sense it directly; and they send that information electronically to a monitoring device. Load pins are used in standard or specially made bow shackles to replace the normal pin. They too contain strain gauges; but in this case the deflection of the pin and the strain are transverse across the load. The pin, therefore, deforms not on tension but in shear. Again, strain gauges measure the deformation; but more complex calibration is needed to convert this data into a load reading.
DLM’s ATEX load pin and their standard telemetry load pin can transmit to their dongle and from there to a computer.
Southampton-based DLM are specialists in the design and manufacture of below-the-hook load monitoring and cable working equipment for the lifting and rigging industries. The load cells within pins and shackles have a transmitter board which sends a 2.4Ghz signal to a handheld device, say a smartphone or a tablet, or it can send it directly to a PC through a dongle device. “The dongle is a product that was only released to market last year,” says their technical manager Ryan Phillips. It is Microsoft Windows based and can be used to generate certificates,
log data, or to show live readings. “Some clients wanted to feed the output from our load cells directly into their computer. You can still use a handheld as well if desired – the dongle just makes it easier getting the data into the PC.” The telemetry load pins are battery powered – these are also the pins used in DLM’s Telemetry Shackles, which combine a load pin with a marine grade shackle. “We custom design and manufacture the pin to fit the shackle; it is the entire pairing that is considered a unit. But we also do cable-powered versions of load cells; these are intended to be used in permanent power solutions.” For telemetry load cells, the battery is
rechargeable via a USB. Users are not able to access the batteries for safety reasons, as they are lithium; they are built into the load cell end cap and can only be accessed by DLM. They give up to 700 hours of continuous use – non- continuous use is two years. The device would be paired with a handheld display that gives a warning of low charge.
Load pins for DLM can transmit to a hand-held device or a dongle.
“500t capacity is the highest available in our standard product range,” he says, “but we strive to meet even the most demanding of customer requirements, meaning we essentially don’t have a limit for custom-made load cells, which we offer in a variety of formats. For sub- sea applications once again we aim to meet the specific needs of our customers, but our standard products can withstand pressures down to 2,000 metres.” We have done no more than scratch the surface of the almost infinite variety of below- the-hook devices; but it is a flavour of what is available. So if you are lifting a load, think beyond hooks and rigging slings. There may well be something much more convenient, much more efficient and a little bit more ingenious out there, that might just be exactly what your load requires.
34 | December 2025 |
www.hoistmagazine.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79
