Patent GB-1168509-A (GB)
Title: An Automatic Sorting System
Inventor: CAMBORNAC MICHEL
IPC: B65G47/49
Filed: 1967-06-14
Abstract: 1,168,509. Sorting postal mail; labels. M. CAMBORNAC, J. CHAZOT, and L. PUECHBERTY. 14 June, 1967 [19 May, 1967], No. 27551/67. Headings B8A and B8F. [Also in Divisions B7 and H4] In an automatic sorting system for mailbags 11, Fig. 5, or like articles, being conveyed upon a conveyer 60, labels 10 are attached to said mailbags which have surfaces upon which particulars of the destinations of the mailbags are written, and which contain radio apparatus for receiving a signal from an interrogating station and for transmitting a characteristically coded reply, using power received from the said interrogating station. As described, an interrogating station ahead of a branching place 62 is provided with an enclosure 50 containing a transmitter and a receiver which are activated only when a mailbag passes by and obscures a light beam 521- 522 directed upon a photo-electric cell. Power radiated by an aerial 511 is received by the apparatus in the label 10, from which a reply is received by an aerial 531. A label may be approximately 6 cm. by 12 cm. and comprise a plate carrying on one face miniaturized or integrated electronic circuit components which are embedded in plastics material, and providing on the other face a surface for a written address. It may comprise a female connector 80, Fig. 3, into which may be inserted an interchangeable key 90, Fig. 3a, for setting up a particular code. In one embodiment the responder circuit of a label comprises an aerial 211, Fig. 7, coupled to an inductor 212 which resonates with a capacitor 213 at the frequency F of the interrogating transmitter. A capacitor 222 is charged through a diode 221 when a signal is received and power is supplied to an R.F. oscillator 23, comprising a PNP transistor 234, and to ten modulating oscillators 240-249 comprising NPN transistors 2400-2490. An aerial 231 is coupled to an inductor 232 in the oscillator 23 which resonates with a capacitor 233 at the response carrier frequency f of the label circuit. The modulating oscillators comprise resistance/ capacity phase shifting networks and oscillate at different intermediate frequencies Ifo to Ifg. Their outputs may be coupled to the oscillator 23 by connectors 200-209, which may be provided by the key 90, Fig. 3a. With ten modulating frequencies available 2<SP>10</SP>, or 1024, codings are possible. In a second embodiment, the label circuit is arranged to divide the response time into ten intervals, and is provided with means for transmitting on two frequencise, f 1  and f 2 . During the first interval a start signal (f 1  only) is returned to the interrogating station and during the remaining nine, a code signal (f 2  in all, plus f 1  in four), 126 combinations being available. A capacitor 222, Fig. 9, supplies power to a resistance/capacity coupled oscillator 240 producing rectangular waves, a ring counter 71 with decoder 72, and to two oscillators 23, 23<SP>1</SP> having respective aerials 231, 231<SP>1</SP> from which response signals at frequencies f 1  f 2  may be radiated. The oscillator 23 is controlled by an AND gate 74 with inputs from the oscillator 240 and an OR gate 73. The oscillator 23<SP>1</SP> is controlled by an AND gate 75 with an input from the oscillator 240 and an inverted input from the output " 0 " of the decoder 72. The OR gate 73 has one input from the output " 0 " of the decoder 72, and another from a terminal which is connected to a tooth on the key 90 when it is inserted. The key 90 is also connected by coding teeth via terminals and diodes to selected ones of the outputs 1-9 of the counter 71 and decoder 72. When the interrogating signal is received the counter 71 is at zero, and the negative half wave from the oscillator opens the gate 74 and closes the gate 75 so that the oscillator 23 sends the start signal (f 1 ) There after, as the counter 71 is stepped, the gate 75 is opened at each of the remaining nine intervals so that the oscillator 231 sends a signal at the frequency f 2 . The gate 74 is only opened when at a particular step a tooth on the key 90 has been provided, so that an impulse is transmitted via the key to the OR gate 73, and thence to the said gate 74, when the oscillator 23 sends a signal at the frequency f 1 . At the interrogating station (Fig. 10, not shown) two separate receiving means are provided, one tuned to the frequency f 1  and the other to the frequency f 2 . Their outputs operate a decoder via circuit arrangements including a shift register and a counter. A detector for the passage of a mailbag controls the two receiving means and resets the shift register and the counter. In a third embodiment, a common carrier frequency F is used for interrogation and response, and signals from the fixed station are modulated at a clock frequency JH. A detector 52, Fig. 12, at the fixed station triggers a programmer 120 when a mailbag arrives so that a clock frequency oscillator 128 generates a train of ten pulses which modulate a transmission at carrier frequency from a transmitter-receiver 122 and also cause a ring distributor 125 to advance step by step. At the label, the modulated wave is received by a transmitter-receiver 112, Fig. 11, is detected by a detector 113, is separated into stepping pulses and a feed voltage by filters 114, 115, and is applied to a ring counter 116. This successively feeds the ten terminals of a connector 117, in which is inserted a key 90 having teeth according to the coding appropriate to the mainlbag. Where there is a tooth, a voltage is passed back to the transmitter-receiver 112 which operates a variable reactance element, e.g. a diode, in the oscillatory circuit thereof, and modulates the retransmitted wave of frequency F. At the fixed station, signals received by the transmitter-receiver 122, Fig. 12, are demodulated and detected and applied to the input of the ring distributor 125. The signals are thus successively directed towards each of ten trigger circuits of a register 126, and those which are modulated as a result of the label coding operate a decoder 127.