GB1389193A - Machines for sorting elongate objects - Google Patents

Abstract

1389193 Sorting nails GKN (SOUTH WALES) Ltd 28 March 1972 [30 Dec 1970] 61813/70 Heading G1M An apparatus for sorting nails comprises a guide 1 along which the nails pass points first, a probe 12 which is positioned so that its tip abuts the point of an acceptable nail as it is discharged Fig.2, (not shown) but not that of an unacceptable nail Fig.3, (not shown), a hopper 3 into which the nails fall, and a flap 7 operated according to whether or not each nail point has contacted the tip of probe 12 to open an accept aperture 5 or a reject aperture 6. In one embodiment (not illustrated), acceptable nails electrically bridge the gap between probe 12 and guide 1 to move flap 7 to the accept position. In another embodiment (not illustrated), unacceptable nails strike an axially slidable sleeve mounted on probe 12 which controls flap 7. In the preferred embodiment shown in Fig.1, the probe 12 is mounted on a piston 13 movable axially when a nail strikes the tip of probe 12, against the bias of air pressure in a cylinder co-operating with piston 13. A rod 18 is mounted on piston 13 and has an aperture cooperating with an air jet sensor 19 such that the air jet is normally interrupted but is allowed to pass when piston 13 moves axially under the impact of an acceptable nail. A second air jet sensor 41 is provided which detects the passage of each nail past the end of the guide, each nail interrupting the air jet. If an unacceptable nail is discharged, it first interrupts air jet 40 and thus momentarily removes the control pressure applied through line 42 to monostable fluid logic device 43. As a consequence, a pressure pulse is applied via line 45 to fluid logic device 22 so that pressure from line 23 is switched into line 25 and operates a control valve 27 via a restrictor 26 to move flap 7 to the reject position by means of pneumatic ram 32. Pressure is also applied via line 25 to a diaphragm amplifier 29 to cause a pressure to be built up in a reservoir 35, this pressure being applied to device 22 to switch it to its original position so that flap 7 moves back to the accept position. If an acceptable nail is discharged, shortly after the interruption of air jet 40 causes line 25 to be connected with line 23, a pressure pulse is applied to device 22 by air jet 19 to switch device 22 to its original position before the control valve 27 operates, and flap 7 remains in the accept position.