FEATURE


SENSORS & SENSING SYSTEMS


back to the future, forward to the past


Technology and fashion have both come a long way since 1971!


With two moon landings, Britain launching its Prospero satellite, CAT scanners promising to revolutionise medicine, and talk about something called a ‘microprocessor’, 1971 was a momentous year for science and technology. It also saw a new magazine take off and a giant leap in torque measurement. Mark Ingham, sales manager, Sensor Technology, comments


I


n 1971 some people were pairing Afghan coats with bell-bottoms and campaigning against the Vietnam war. Others, in suits


and ties, were campaigning to join the European Economic Community. Disney World Florida looked set to change Orlando from a torrid swamp into a tourist hotspot, and Qatar gained independence from the United Kingdom (with its new decimal currency). On the industrial and engineering fronts,


Rolls-Royce was nationalised but Upper Clyde Shipbuilders was liquidated; ambitious young engineers signed up with the new Open University – perhaps hoping that one day they would be able to afford a state of the art Morris Marina and drive across that civil engineering marvel Spaghetti Junction; London Underground’s Victoria Line was completed; Dennis Gabor won a Nobel Prize for inventing the hologram; and video tape recorders had been miniaturised to the point that they were smaller than stereograms. Much of this activity was being reported by editor Bob Hersee in his new magazine, OEM


Design (the genesis of today’s Design Solutions). Had the M40 existed then he would have had an easy trip from Wembley to Banbury to visit Anthony and Bryan Lonsdale at their instrument calibration company, to see their pioneering work in torque measurement. In fact these twins had had a successful few


years working on their clients’ need for real- time torque monitoring and were planning to start a new company, Sensor Technology, to commercialise the developments. Originally, they had worked on refinements to


the only real option of that time – fixing multiple strain gauges to rotating shafts and collecting readings from them using a hardwired slip ring arrangement. By standardising on components and procedures they achieved some success, but feedback from the field suggested that nobody liked slip rings as they were fiddly to set up at the start of each test run and so delicate that they often broke or failed in use. So the brothers were soon ready to think out of the box and look for some innovative alternative ideas. After a good deal of research, they realised


14 DESIGN SOLUTIONS JULY/AUGUST 2021


that they could replace the slip rings and hard wiring with a radio frequency (RF) transceiver. As the transmission distance was only a few millimetres, the signal did not have to be very powerful, so there were no interference issues to worry about.


a breakthrough By 1971, just as OEM Design was building its readership, they had perfected and were commercialising an optical solution to torque monitoring. The measurement technique they developed was based on two encoder discs mounted on the shaft under test. Each disc is opaque but has a grating, or regular radial lines etched onto it, through which light can pass. Initially the gratings on each disc align so that a light can be shone through them. However, as the shaft starts rotating the


torque causes a slight degree of twist along its length and the gratings move out of alignment. This either reduces or increases the amount of light that can pass through both discs, depending on the direction of the torque applied.


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  |  Page 80  |  Page 81  |  Page 82