Patent GB-1214899-A (GB)
Title: Improvements in auto-dialling devices
Inventor: DEMIDOFF BENJAMIN
IPC: H04M1/274
Filed: 1968-09-11
Abstract: 1,214,899. Magnetic recording and playback. B. DEMIDOFF. 10 Sept., 1969 [11 Sept., 1968; 9 Dec., 1968], Nos. 43203/68 and 58394/68. Heading G5R. [Also in Divisions H1, H4J and H4K] A dialling code stored in a memory e.g. a magnetic tape is selectively addressed by virtue of the position of a blade which is stopped, in its normal lines movement below a keyboard, by the stem of a depressed button corresponding to the wanted party. The buttons 1-10 of Fig. 3, are arranged in a co-ordinate array in a keyboard bearing called-party identification slips adjacent each button. The blade 11 is inclined to the directions of movement (which is towards the operator) so that when it is stopped by a depressed button its position uniquely identifies that button. The blade may carry a replay/record head over a magnetic sheet, stoppage of the blade causing the hand to traverse the sheet in a direction normal to that of the blade's movement. Alternativey the blade may carry the sheet. A repertory of 100 may be housed in a plith unit for a standard telephone subset. The movement of the blade may be effected by electrical or mechanical means e.g. by the energy stored in a spring when the keyboard is withdrawn, in the manner of a drawer, from the plinth unit. The keyboard comprises 28 rows of alternately three and four push-buttons and one row of two buttons, thus providing for up to 100 parties. (Fig. 1, not shown). The buttons e.g. 9 (Fig. 3) may be retained in their unoperated positions by springy strips 11 bent up from a thin stainless steel sheet 4 which overlies an insulating sheet 5, a copper sheet 6 and an insulating support plate 7. Upward movement of the buttons is limited by flanges 12 which engage the underside of another support plate 3 for identification slips 2 and a transparent cover 1. Depression of a button causes strips 11 to contact copper sheet 6 and thus close an operating circuit for an electro-magnet which initiates movement of the blade. In an alternative embodiment (Fig. 4, not shown), each button is individually (spiral) spring loaded and the underface of the flange is metallized so as to lose an operating circuit when the button is depressed. The buttons may be of plastics material with a metal core or of all metal construction with a plastics sleeve on the part which is touched. In both the above embodiments, the button must be held down until an audible or visual signal indicates that the blade has been stopped and the button locked by the entry of a leading edge of the blade into a groove 16 in the button stem. An inertia switch carried by the blade closes the necessary circuits for generating the signal. In two further embodiments (Figs. 9 and 10, not shown) a spring loaded lever or a wire spring per se may be effective to lock the buttons as soon as they are depressed, the lever or spring arm entering the groove 16 (Fig. 3) formed in the button stem when this appears below support plate 7. The operative (and any other accidently operated) buttons are restored by axial movement of a set of rods which disengage the levers or spring arms from the grooves. The blade (Fig. 5) comprises a first leading strip 24 which enters the groove in an operated button's stem so as to lock it, a second strip 23 which abuts the button stem and a channel base member 22 in which the two strips are resiliently mounted so as to provide a shock absorbing function and an inertia switch function. The switch, which comprises two contact sets (in each of which both contacts are resiliently mounted relative to the base member) for indicating respectively correct stoppages of the blade and incorrect stoppage (e.g. leading strip 24 not engaged in groove but merely obstructed by button stem), is mounted at the centre of the blade (Figs. 6, 7, not shown). The blade assembly is located in a peripheral frame, mortice and tenon fashion 25, 26, or on a centrally disposed rail for longitudinal movement by a screw driven by a prime mover. Repertory magnetic memory, (Fig. 12).- The previously mentioned 100 party memory may be enlarged by recording (visually and magnetically on a length of tape which can be manually moved by a sprocket 68 located intermediately a take-up and a feed spool 67. The mechanism 69 lifts the tape free of the buttons (not shown, in Fig. 12) and then shifts it in steps (of e.g. two rows) from one spool to another before letting it drop back over the buttons. The stepping is controlled by detent 75 which drops into a recess 74 after riding on the periphery of wheel 73 during the manual rotation of wheel 73 with sprocket 68. An auxiliary track, possibly on a separate tape, may be provided for recording the number of a called party who is engaged, this number repeatedly being called until he answers whereupon the track can be cleared without involving the repertory portion of the memory.