Patent GB-655113-A (GB)
Title: Improvements in printing or recording apparatus
IPC: G08C25/00
Filed: 1948-04-06
Abstract: 655,113. Fire, police and like alarm systems. ERICSSON TELEPHONES, Ltd., and SINCLAIR, W. April 6, 1948, No. 9544. [Class 40 (i)] [Also in Groups XVI and XL (b)] Printing apparatus, particularly for recording at a central station particulars of a burglar or fire alarm call, comprises a plurality of typewheels each set independently by electromagnetic ratchet-and-pawl mechanisms (to record, e.g. particulars as to the origin and type of call), a further plurality of type-wheels set by a single ratchet-and-pawl mechanism to positions determined by intercouplings between them (to record, e.g., the time of the call in hours and minutes), and electromagnetic means for bringing a paper sheet into operative contact with the set type wheels, the printing being on the opposite side of the paper from the typewheels and being rendered visible immediately after the completion of the printing operation. The apparatus shown, which is particularly applicable to the alarm system described in Specification 629,314, is formed in two units, one, Fig. 2, comprising the paper-feed and printing-mechanism, and the other, Fig. 3, comprising the type-wheels and their setting mechanism. The former is screwed to the base 19 of the latter, and a cover 1, Fig. 1, fits over the assembly with slots in flanges 105 engaging projections 103. The cover includes a detachable panel (not shown), covering the window shown in the upper part of Fig. 1 and the whole is fastened by a lock, of which the latch-plate engages a lug 2 on the striker-bar back-stop 106. The assembly may pivot about a bar 20. Type-wheel assembly. The independentlyset type-wheels 89, 90, 91, corresponding respectively to the number of the calling line, the number of the station on the line, and the type of call, e.g. testing or "action," are set by ratchets controlled by magnets 66, wheel 90 being set in reverse direction by a magnet, not shown. Each magnet operates over selfinterrupter springs 73 and the extent of movement is in each case determined by the engagement of a wiper 71 with a marked terminal. The time type-wheel assembly comprises an hour wheel 96 and tens and units minute wheels 97, 98. The ratchet 68 of the units minute wheel 98 is operated at one-minute intervals by a magnet (not shown). At each tenth step of wheel 98, a toothed slot drives a pinion 94, and a connected pinion advances the tens-minute wheel 97 one step. Similarly, at each sixth step of wheel 97, a disc 72 moving with the wheel drives pinion 95 to advance the hour wheel 96 one step. The movement of the units minute wheel is transmitted through gearing 99, 100 to set a time indicator 18, the minute-hand of which is attached to a shaft 117, Fig. 4, bearing a crown-wheel 116 meshing with pinion 101 on shaft 115. The hour hand is set through epicyclic gearing comprising pinions 121 on a plate 120 fixed to shaft 117, the pinions meshing with a movable gear 119 attached to the hourhand arbor and with a fixed gear 118 having a smaller number of teeth. The indicator hands may be adjusted by depressing button 5, to remove the operating pawl from ratchet 68, and turning shaft 115 by hand. Printing and paper-drive mechanism. The paper roll 111, Fig. 2, is held between spring- pressed discs 113, and the paper 16 is fed under rod 57, between knurled sections of spring- pressed rod 51 and drive-wheels 49, over guideplate 50, between the type-wheels and the inked ribbon 7, and out to the front of the equipment through a slot at the bottom of the detachable locking panel. A spring-pressed roller 60 contacting the outside of roll 111 controls, through a crown-wheel 21 and a flexible shaft 24, a paper indicator 17, Fig. 1. Printing is effected by striker arms 41 controlled by magnets 64 and carrying the striker bar 13 with rubber pad 14 which presses the inked ribbon 7 and the paper into engagement with the set type-wheels, the printing taking place on the side of the paper remote from the type-wheels. A bar 44 held in contact with striker arms 41 by a blade-spring 45 is carried by arms 47 which are pivoted on short shafts 122 carrying the paper-drive wheels 49 and are connected to the wheels through one-way spring clutches whereby, as the bar 44 rises after the printing operation, the paper is advanced to show immediately the printed measage 15, Fig. 1. The inked ribbon 7 is carried by two spools 6 carrying ratchet-wheels 28 associated with pawls 29 carried by pawl arms 30 controlled by cams 43 carried by the striker arms 41. Only one pawl is operative at a time, the other being held inoperative by a movable bar 34 supported by pivoted links 38 and having two (left and right) positions in each of which it is held by a spring 35. When a predetermined quantity of ribbon has been wound from one spool, a pivoted arm 8, Fig. 1, lifts a pin 11 attached to linked arms 63, 33 on the bar 34 causing arm 33 to be struck by a cammember 32 to move the bar to its alternative position, thereby reversing the drive.