Cheap and effective chain wear indicator

grabcad

In this construction I used 2 optocouplers (optical switch, optical slot sensor etc: The combination of transmitter and receiver, the sensor responds to interrupt of the beam by external opaque object). I placed sensors at a distance Lgauge= Lnormal *n, where n =1,2,3…(or according to ISO or user manual n=5,7,9,11 ...) If the chain is unweared and Lnormal=Lgauge , then when it moving up or down the sensors will give the identical signals, that means all events in output sensor signals will occurs simultaneously. If the chain is weared and Lextended> Lnormal, when chain moving all events in output sensor signals will occurs not simultaneously, one earlier and one later (depending on direction of movement), phase shift is appeared. Cheap microcontroller can processed this phase shift in output signals. This idea is well realized with other types of sensors, like magnetic (inductive or combination of Hall sensor or reed switch and permanent magnet) or capacitive sensors. It must be placed on opposite to welded area side. In this case shape of output sensor signalse will be similar to optical sensors. I think it's better for use than optical sensors because they are less sensitivity to dirt, dust and other pollute and not needs protection from external light. It’s also possible to use mechanical switch but why? It will be wearing, so better to use contactless sensors. Unfortunately I have no time for submit new entry, so I add it to this entry. This is evolution of this entry idea. The sense is to use optical linear sensor (CCD or CMOS the similar used in office scanners for paper documents, scanners for cash notes in cash machines) instead simple optical switch. In addition to extension indication by phase shift controlling, linear optical sensor controls the surface of links for cracks, serve nicks or gouges, visible distortion, severe corrosion etc. It will respond to the sudden changes of edges or color change. Also it is possible to write in the memory pattern of unworn chain, and then every time compare image from sensor with the pattern. I think it’s useful to combine both methods for better result. Hm. I'm surprised, but the price of cheapest linear optical sensor is 10-15$ (photo matrix with linear array of pixels from 128 to 4096 pieces), and the cheapest web camera in shop by retail is about 10$ (I didn’t search specially) and it is more complicate and consummate device with 2Mpixels and USB interface. And one or two years ago I buyed 0.3Mpixels camera for cellphone for 4$ only. Thereof with these prices it may be better to use camera matrix. For example for low performance (and cost) microprocessor it’s possible to use only one or two strings of matrix as linear sensor. With the camera it’s possible to use more complete technologies for surface control as 3d laser or shadow scanner like this http://www.david-laserscanner.com/ etc But this decision needs very powerful software. Sorry I had no time for make really good presentation of my ideas, but I hope you will estimated engineering component not designer component (It’s practical but not shine on the picture)