Patent GB-837577-A (GB)
Title: Improvements in or relating to machines for cancelling stamps on mail pieces
IPC: B07C1/20
Filed: 1958-01-09
Abstract: 837,577. Stamp-cancelling machines. PITNEY-BOWES Inc. Jan. 9, 1958 [Jan. 15. 1957], No. 906/58. Classes 100(1) and 100(2) [Also in Group XL(b)] General arrangement. A machine for cancelling stamps on mail pieces comprises a feeder arranged to feed the mail pieces in succession along a path, detector means adjacent the path and arranged to detect the presence of a stamp on each mail piece and the location of the stamp with respect to the leading edge of the mail piece and cancelling means controlled by the detector means for cancelling the stamp at a point on the path later than the detector means. Envelopes are stacked. in a hopper 21 (Fig. 1) and fed in succession to a stamp detector 49, comprising two inductive coils 63, 65, by a feeder 31 which is as described in Specification 787,495. The envelope is next fed, by feed rollers 39, to a photoelectric leading edge detector 51. The two detectors are arranged in an electric circuit with actuating solenoids for stamp cancelling printers 53T and 53L, one or other or neither of these being set in motion depending upon the position of the stamp upon the envelope as sensed by the devices 49, 51. The envelopes are then passed into one of three receivers 41T, 4lL or 45 under the control of switches 57T and 57L. The printers 53T and 53L are similar, the postscript Tor L depending on whether the printer is for the trailing or leading edge of an envelope. Each contains impression roller 79, printing die 81 and inking roller 83. The printer 53T is driven by a shaft 85T (Fig. 8) including a slip friction clutch and provided with a projection 87T normally engaged by a latch 89T rockable on a pivot 91T and held in position by a stop 93T and spring 95T. Latch 89T has a lip 97T which lies in the path of a rotary timed element 99T driven through a friction clutch. Element 99T also carries a stop 101T normally engaged by a latch 103T rockable on a pivot 105T against the action of a spring 109T. Linkage 111T is connected between latch 103T and the armature 113T of a trail print solenoid TP. Energization of solenoid TP thus permits shaft 85T to rotate and cause printing by the printer 53T. The printer 53L is provided with corresponding operating elements except that a further solenoid PA is provided having an armature 121 connected by a link 123 to a pivoted blocking element 117 which engages a shoulder 127 of latch 89L to prevent withdrawal of the latch when it is engaged by the trip element 99L on energization of the solenoid LP. The lip 97L is for this purpose swingably mounted on the latch 89L. To effect operation of printer 53L, therefore, both solenoids LP and PA must be energized. All the machine parts are driven in timed relation to the feeder 31 by suitable gearing, as shown in dotted lines in Fig. 8. Sheet delivery apparatus. Envelopes printed on by the printers 53T and 53L are diverted into receivers 41T and 41L respectively. Envelopes not printed pass through guides 131 and 133 to receiver 45. Switches 57L and 57T for deflecting printed envelopes into receivers 41L and 41T respectively are mounted on shafts 135L and 135T (Fig. 4). The shaft 135L is provided with a bell crank lever 139L having on one arm a cam follower roller 143L co-operating with a cam 145L, and on the other end a stop 141L engaged by an arm 153L controlled bv a solenoid LG. when solenoid LG is energized a force is applied to arm 153L tending to free it from engagement with stop 141L. The arm remains in position, however, due to friction created between the arm and the stop by a strong spring 161L. When the raised portion 159L of cam 145L engages roller 143L the lever 139L is slightly pivoted thus freeing the arm 153L and allowing the roller 143L to fellow the low portion of cam 145L. The switch 57L is thus pivoted clockwise as viewed in Fig. 4, and the envelope diverted to receiver 41L. Before the portion 159L of cam 145L again engages roller 143L the solenoid LG is de-energized so that arm 153L rests on stop 141L until the bell crank is rotated anti-clockwise by engagement of cam portion 159L with roller 143L. The switch 57T is similarly controlled by a solenoid TG. Control and operation. The envelopes are stacked in the hopper 21 on one of their longest edges and the printers 53T and 53L are adapted to print on stamps adiacent this edge. The stamp detector 49 only detects stamps adjacent this edge. The envelopes mav be in one of six different conditions. If the stamp is in the usual position in the upper right hand corner of the envelope, then with the stamp adjacent the lower edge as the envelope passes through the machine it will be either adjacent the trailing edge on the side of printer 53T or adjacent the leading edge on the side of printer 53L. If the stamp is adjacent the upper edge, no printing is effected and the envelope travels straight through to the receiver 45 together with unstamped envelopes. Envelopes having a row of stamps too long for effective cancelling also pass to receiver 45. The envelopes thus collected are inverted and fed through the machine a second time so as to remove from the residual stack of unstamped envelopes and envelopes to be cancelled by hand in receiver 45 those which on the first run had stamps, adjacent their upper edges. Control is effected by the circuit shown in Fig. 12. If the envelope fed by the device 36 to the detector 49 has a stamp adjacent its lower and leading edges as the stamp passes between the inductive coils 63, 65 the inductive coupling as upset (the stamp having a metallic content) and a relay 217 de-energized thus putting a preliminary bias, through switches 219 and 225 on to the grid of a thyratron LT and energizing relay 241 to form a by-pass circuit around switch 219 for the bias to thyratron LT when relay 217 is re-energized. When the leading edge of the envelope is detected by the photoelectric device 51 relay 223 controlling switch 225 is de-energized so that the bias is suddenly removed from thyratron LT and relay 241, the inductive reaction of which brings about a rapidly decaying transient voltage which is transmitted to the thyratron and causes it to fire. A coil LC of a polarized relay 235 is connected in series with the plate of thyratron LT and is energized when the thyratron fires thus operating switch 253 to apply current to lines 255 and 255a. The solenoids LP, LG and PA are all thus energized so that the printer 53L is operated to cancel the stamp and switch 57L is operated to divert the envelope into receiver 41L. If the stamp is adjacent the lower and trailing edges of the envelope the edge detector 51 is operated before the stamp detector 49 so that before relay 217 is de-energized, relay 223 is energized and switch 225 makes contact with the grid circuit of a thyratron TT. When relay 217 is de-energized the bias over switch 219 is thus applied to thyratron TT. A by-pass circuit for switch 219 is effected by energization of a relay 245 when switch 219 closes. When the trailing edge of the envelope leaves detector 51 solenoid 223 is re-energized thus removing bias from thyratron TT and relay 245, the inductive kick of which causes thyratron TT to fire and energize coil TC of relay 235. Current is thus supplied to line 257 causing energization of relays TP and TG to cause in turn printing by printer 53T and positioning of switch 57T to deflect the envelope into receiver 41T. If the envelope has no stamps thereon or stamps adjacent its upper edge nothing is detected by, the device 49 so that switch 219 does not close and neither thyratron can fire. The envelope then passes directly to receiver 45. If the envelope has a lengthy row of stamps thereon adjacent its lower edge detection of the stamps will take place before detection of the leading edge no matter on which side of the envelope the stamps are located. The machine will thus treat the envelope initially as one having a stamp adjacent its leading edge anct on detection of this edge by the device 51 thyratron LT will fire and switch 225 will move over to contact 229. However, as stamps are still being detected by device 49 switch 219 is still closed so that thyratron TT is conditioned for firing and fires when the trailing edge of the envelope leaves detector 51. Thus both coils LC and TC are energized and the switch 253 accordingly takes up a central position. Since current was passed over lines 255 and 255a between the firings of thyratrons LT and TT solenoid LP has been energized and set in motion the mechanism for operating printer 53L. However, printing is blocked by the blocking element 117 as with the repositioning of switch 253 solenoid PA is de-energized. A cam operated switch 237 is provided in the plate circuits of the thyratrons to ensure that both are quiescent at the start of a cycle.