1,039,318. Rotary conveyers-grippers thereon. AEROJET-GENERAL CORPORATION. June 16, 1964, No. 24873/64. Headings B8A and B8H. [Also in Division G4] A machine for sorting letters comprising a carrier formed of framework 2, 4, 6, rotatable on a vertical shaft 8, a circular surrounding stationary assembly 20 including an induction station, a code reading station, receiving stations and a residue station for the letters, letter transporting heads 10 radially movable on the carrier, cam means adjacent the induction station and engageable with each transporting head 10 to cause it to engage a letter and cam means at each receiving station engageable with each transporting heads 10 to cause it to deposit a letter carried thereby at that receiving station. Each transporting head 10 incorporating a pipe section 28 is coupled to a suction tank 14 by a hose 12 and a pipe section 30, slideable in a tubular guide, the latter being secured to a plate 26 secured between a pair of vertically spaced annular rails 2, 2<SP>1</SP> of the carrier frame. The head 10 comprises a tubular body of greater diameter than the pipe 28 to which it is secured, Fig. 8 (not shown), with apertures in the radially inward wall surrounding the pipe receiving aperture and apertures in the radially outward wall. A valve on the head to control suction thereto, comprises a circular plate on the inside of the tubular body which overlies the end of pipe 28 and an annular plate 52 radially inwards of the tubular body which overlies the apertures in the radially inward wall thereof, the two plates being rigidly coupled together. The latter plates are freely mounted to the transport head 10 and under the action of an incorporated cam roller 58 either admit or release suction at the head. A pair of vertically spaced wheels 64 are pivoted to the leading end of the head 10 to depress a pack of letters already in a receiving tray 22r at a receiving station for insertion of a letter carried by the head. A rod 68 slidably mounted in a guide 70 is rigidly connected to the pipe 30 for movement therewith. The rod 68 is spring biased into the radially inward position and includes a cam roller 82 which engages a cam track 84 at the stations to move the transporting head 10 into the radially outward position. A block 92 carrying a plurality of spring- loaded pins 94 (see Fig. 11, not shown) is mounted from the plate 26 associated with each head 10. Selected pins are pushed into their upper positions by solenoid-operated levers in response to signals from the reading head generated due to dye markings on the letter, so as to engage micro switches 104 secured to the stationary framework upstream of a receiving station. Synchronisation of pins 94 and switches 104 at a receiving station operates a solenoid to release a spring-biased movable upstream section 86 of the cam track 84 whereupon the cam roller 82 is fed into the latter track. A further cam track 88 adjacent the receiving tray 22r engages the roller 58 causing the suction in the head 10 to be released. A rear portion 60 attached to the head 10 depresses the movable cam track section 86 into its locked-down position as the head 10 passes along the fixed track 84. Any letters not deposited in a receiving tray are automatically deposited in a residue tray 22u downstream of the receiving trays. A curved block 126, Fig. 13 (not shown), received above the path of the heads 10 engages and causes all the pins 94 to be pushed down again upstream of the induction station 22i. A fixed cam track at the induction station engages the roller 82 to draw the head radially outward and a further cam to actuate the suction valve to introduce suction whereupon the first letter in the induction tray is picked up. The head 10 is held radially outward by the cam track as it passes the reading station. Signals from the reading head actuate solenoid-operated levers mounted from the stationary framework which maintain pin-engaging beams in an upward position to push the relevant pins into the upper position. Each of the trays at the induction, receiving and residue stations comprises bottom and side walls and a top wall with a central longitudinal slot, and a back plate having a pulley in each corner which moves longitudinally in the tray. A system of cables attached to the tray and passing around the pulleys, Fig. 21 (not shown), maintains the plate vertical. A spring-loaded pin which engages holes in the top of the tray, is mounted on the rear of each back plate, the pin being disengageable from the holes by a pivoted lever. When the tray is used as a receiving tray the lever is locked in the pin disengaging position and when used as an induction tray the pin is disengaged when a motor-driven screw advances the back plate by engaging the lever. A pivoted lever engaging the leading letter in the induction tray controls the switch for the screw motor. A number of these carriers and trays may be mounted in vertical relationship and move them one bank of induction, reading, receiving and residue stations may be arranged at one level Fig. 29 (not shown). In a further embodiment, Figs. 26-29, the transporting heads 10 instead of reciprocating radially move radially about a pivoted point on the carrier frame.