GB1386985A - Electronic apparatus for setting and checking the electronic yarn clearers - Google Patents

Abstract

1386985 Yarn clearer systems; electronic control LOEPFE BROS LTD 30 May 1972 [27 May 1971] 25309/72 Headings D1F and D1J [Also in Division Gl] In a yarn clearer system a running yarn is passed through a sensing head including a contactless yarn sensor e.g. photoelectrical sensor and a sensing signal is produced which is fed to a signal processing means 1. The signal processing means 1 includes at least one controllable processing channel e.g. double-yarn channel C, nap channel N or yarn diameter channel D. The signal fed to the control channel is amplified and fed to a threshold discriminating means, and when the fed signal reaches the threshold level of the discriminator means, a signal is sent to actuate a yarn severing means 4. An electronic checking and setting apparatus 2 is provided which includes a controllable d.c. amplifying channel which exactly duplicates the amplification of any signal fed to the signal processing means 1. An indicator 8 receives the output of the said controllable amplifying channel and in setting the apparatus, a full scale reading is given when the threshold level of the discriminating means is reached, therefore a full scale reading is reached every time a severing signal occurs. The signal processing means 1 and electronic checking means 2 are preferably mounted as a single unit on a base plate 11 with a sensing means 4, 5, a bobbin holder 12, a draw-off means 14 and yarn guides 21. The electronic checking means 2 is provided with a signal level compensating means to compensate for the constant base signal of the sensing signal. In setting, for example, the double-yarn channel C, a switch in the checking means 2 is set to receive signals from the control channel corresponding to the channel C. A control yarn 18 is drawn through the apparatus but without passing through the sensing head 4, 5. A push-button OS is actuated to hold in the compensating means until the indicating device shows zero reading whereupon the button OS is released. The yarn 18 is then passed through the sensing head whereupon a positive reading on indicator 8 is given. The channel C is then adjusted in processor 1 until the indicator gives a 70% full scale reading; under these conditions the 70% reading indicates the mean diameter of a yarn and the full scale reading corresponds to a yarn with a crosssectional area twice that of the mean crosssectional area.