Patent GB-285062-A (GB)
Abstract: 285,062. Neufeldt & Kuhnke Betriebs- Ges. Feb. 10, 1927, [Convention date]. Apparatus for signalling any of a number of possible indications. - In a photo-electric signalling, regulating car measuring arrangement, a regulating frequency dependent on the state to be measured tends periodically to set connecting operations in motion and a comparison frequency, independent of the state to be measured, attempts periodically to annul the effect of the regulating- frequency. By means of a measuring instrument, such as a thermometer, barometer, pyrometer, galvanometer or turbidometer, a varying amount of light, for example, dependent on the position of a mirror moved by the measuring instrument, is thrown on a photo-electric cell 1, Fig. 2. The photo-electric current charges a condenser 6, which is discharged through the closing of contact 9, once in each revolution of a cam disc 8, which also closes a contact 10 slightly before the contact 9. If, in the period of revolution, the charge on the condenser does not reach a sufficiently high value to operate a glow relay 3, a relay 4 does not act and its armature 12 remains as shown. Consequently a battery 13 is connected through the contact 10 to a relay 15, which closes a locking circuit through a retaining contact 18 and remains energized until the charging period of the condenser becomes shorter than the period of the rotating cam disc. When this occurs the relay 4 is energized, the armature 12 is lifted from contact 14, the relay 15 becomes de-energized and the armature 12 engages contact 16. If the operation of the glow relay occurs at a time when a contact 11 is alreadv broken a relay 17 cannot act and both relays 15, 17 are de-energized and the light falling on the cell has an intensity corresponding to the required condition of the measuring instrument. If the cam disc at the time of action of the relav 4 is still as shown the relay 17 is temporarily energized through the contact 11. Thus the relay 17 acts if the light exceeds a prescribed value and the relay 15 acts if the light falls below the value. To signal to a distance the reading of the measuring-instrument the condenser is made variable and so arranged that its capacity increases when the relay 17 acts and decreases if the relay 15 acts. The value of the condenser therefore acts as an indication of the reading of the measuring-instrument and is used to control a transmitter. According to a modification the comparison frequency is generated by running-down mechanism wound up periodically by the photo-electric current. A lever in the mechanism mav be lifted bv an armature, Fig. 3 (not shown) or may be directly fitted to the armature of a magnet excited by the glow-relay, Fig. 4 (not shown). As shown in Fig. 5, a double lever 41, 42 drops under the control of a rotating toothed wheel, not shown, and. at the end of the stroke, places a switch 24 against a contact 25. If the glow-relay now operates the relay 17 acts and a relay armature 33, to which the double lever is fixed, is attracted clockwise. At the end of the attraction the arm 41 cuts off the current by breaking a contact 43 and the arm 42 places the contact lever 24 against a contact 26. If, on running down, the glowrelay acts before the arm 41 has changed over the contact lever 24, the relay 15 acts. The double lever is then swung anticlockwise as before. To compensate variations in the strength of the light source and in the sensitivity of the photo-electric cell, the construction shown in Fig. 6 is employed. A photo-electric cell 54 is struck by a ray of light coming from a lamp 75 through an optical system 79 and a grey wedge 92, and a condenser 55 is consequently slowly charged. During the charging gear wheels 85, 93 are in mesh and the grey wedge is slowly moved to the right by a drive 88, 90. When the condenser is sufficiently charged a glow-relay 57 operates and excites a relay 59 which closes a contact 60. Consequently a current flows from the positive pole through the contact 60, a relay 61, a coil 66 of a relay 65, a coil 72 of a relay 70, a contact 77 and a contact spring 76 to the negative pole of the source of current, and relay armatures 68, 73 are thrown into their other end positions. The retarded relay 61 then breaks the connections at contacts 63, 64 to extinguish the glow-relay, and the contact 60 drops off, the relay 61 becomes de-energized and the armature 62 returns to the position shown. The ray of light now passes through an optical system 80 and a pipe 81, filled with a medium to be tested, to the photo-electric cell and the condenser is again charged. During this charging the pinion 85 is in mesh with a gear wheel 94 and the grey wedge is displaced towards the left. This movement continues until the condenser actuates the glow-relay, when the previous switching is repeated except that windings 67, 71 of relays 65, 70 are energized, and the armatures are returned to the positions shown. The wedge is therefore oscillated about a mean position dependent on the transparency of the medium under test. The transparency is indicated by a pointer 86 and can be communicated by a transmitter 89 and regulating operations can be controlled bv the rack 90. A modification is described for use with a measuring instrument controlling a mirror or the like, Fig. 7 (not shown).