US 3646551 A
Description (OCR text may contain errors)
United States Patent Bretti et al.
KEYBOARD FOR CALCULATING MACHINES, ACCOUNTING MACHINES, TELEPRINTING MACHINES OR THE LIKE Inventors: Franco Bretti; Emilio Gilardi, both of Caluso,ltaly lng. C. Olivetti & Co., S.p.A., lvrea w t l Filed: May 6, 1970 Appl.No.: 35,065
Foreign Application Priority Data May 9, 1969 Italy ..5l764 A/69 US. Cl. ..340/365, 178/17 R, 197/16,
197/98 lnt. Cl ..G08c 1/00 Field of Search 340/365; 235/145; 197/98, 16,
l97/l7; 178/79, 17 C, 17 R  References Cited UNITED STATES PATENTS 3,297,149 l/l967 Hadley ..l78/79 3,306,417 2/1967 Gassino et al.... ..l78/l7 C 3,495,236 2/ l 970 Mathamel ..340/365 Primary Examiner.lohn W. Caldwell Assistant Examiner-Robert J. Mooney Attorney-Birch, Swindler, McKie & Beckett ABSTRACT In a keyboard for calculating and like machines, upon the depression of each key, a corresponding elongated plate is shifted in a first direction substantially parallel to the long edge thereof to prearrange the selective setting of a series of code bars. The setter thus prearranged is thereafter shifted by motor in a second direction perpendicular to said long edge to set the code bars as to produce a corresponding binary code combination. Each plate is provided at the two ends with two U-shaped leaf springs engageable with two universal bars shifted simultaneously by the said motor so as to shift the prearranged plate through a pure translation.
10 Claims, 6 Drawing Figures PAIENTEBFEB29 m2 SHEET 1 0F 3 ENTORS 0 BRETTI 0 GILAR l ATTORNEYS lNV FRANC EMILI PATENWTEUFEBZQ 1912 SHEET 2 0F 3 f L I INVENTO FRANCO BRETTI EMILIO GILARDI ATTORN EYS PAIENTED FEB 2 9 I972 SHEET 3 IF 3 INVENTORS FRANCO BRETTI EMILIO GILARDI 4. rlllh/l/ldflld II I ATTO RN EYS KEYBOARD FOR CALCULATING MACHINES, ACCOUNTING MACHINES, TELEPRINTING MACHINES OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to a keyboard for calculating, accounting, teleprinting or other machines, of the type in which, upon the depression of each key, a corresponding setter is shifted in a first direction in order to prearrange the selective setting of a series of code bars capable of assuming two stable positions and in which the setter thus prearranged is thereafter shifted by motor in a second direction in order to set the code bars so as to produce a binary code combination corresponding to the depressed key, each setter being constituted by an elongated plate provided on a long edge with code projections for operating the code bars. Such a keyboard will be referred to as of the type specified.
In a known keyboard of this type, such as that disclosed in U.S. Pat. No. 2,879,876, each depressed key acts on a lever which engages with the setter, causing this latter to accomplish a rotation substantially perpendicular to the coded edge in order to carry a tooth on the setter into engagement with a grooved shaft actuated by motor. The'grooved shaft causes the setter to accomplish an actuation shift parallel to the coded edge, in order to switch selectively the code bars into one or the other of the two positions, thus setting up the desired code combination. The setter is shifted by acting on the end opposed to that end around which it was rotated upon the depression of the key, whereby on the one hand the setter is subjected to some juddering at the latter end, and on the other hand the code bars near the end engaged by the grooved shaft can be abandoned prematurely by the setter, in the case of premature return of the key.
SUMMARY OF THE INVENTION The object of the present invention is to obviate these disadvantages and to enable all the code bars to be set under the same kinematic conditions.
In accordance with the invention there is provided a keyboard of the type specified, characterized in that the said first direction is substantially parallel to the said long edge, while the said second direction is perpendicular to the long edge, each plate being provided at each of its ends with an element engageable with a corresponding universal bar in consequence of the said prearrangement, the two universal bars being adapted to be shifted simultaneously by the said motor so as to give the same motion of the two ends of the plate thereby shifting the plate by a motion of pure translation comprising motion in the said perpendicular direction.
BRIEF DESCRIPTION OF THE DRAWINGS The following description of a preferred embodiment of the invention is given by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a partial plan view of a keyboard embodying the invention;
FIG. 2 is a right-hand side view, partially sectioned, of the keyboard of FIG. 1, on a slightly larger scale;
FIG. 3 is another partial right-hand side view of the keyboard of FIG. 1;
FIG. 4 is a partial section along the line IVIV of FIG. 1',
FIG. 5 is a partial section along the line VV of FIG. 1; and
FIG. 6 is an illustrative diagram of the coding of some setters of the keyboard.
DETAILED DESCRIPTION OF THE INVENTION The keyboard embodiment described here is applied to an electronic calculator. The keyboard comprises the usual 10 numerical keys 11 (FIG. 1 two keys 12 for entering the point and the minus algebraic sign, 22 function keys l3 and a key 14 (FIG. 3) for unlocking the keyboard. The keys 11, 12 and 13 are set in line on four rows'and are each carried by a lever 16 (FIG. 2). The levers 16 of each row are fulcrumed on a corresponding fixed axis 17. F ulcrumed on each lever [6 is a second lever 18, to which a spring 19 is connected, which keeps the lever 18 normally rested against an ear 21 of a corresponding setter constituted by an elongated plate 22. The springs moreover keep the levers 16 against fixed stops 23. Each lever 18 is provided with a shoulder 24 adapted to collaborate with a shoulder 26 of its lever 16. Each lever 18 is adapted to engage by means of a step 27 the ear 21 on which it is normally rested.
Each plate 22 is guided by two recesses 28 and 29 of two combs 31 fixed to the case of the keyboard and is supported at the two ends by two leaf springs 32 and 33 bent back substantially in the shape of a U in the plane of the plate 22. Each leaf spring 32, 33 has one of the two arms of the U" hooked to the comb 31. The other am of the U" is hooked by means of a slotted hole 34 to a tooth 36 formed on the corresponding end of the plate 22. The two springs 32, 33 thrust the plate 22 upwards, urging it against two flanges 39 and 41 on the combs 31, while longitudinally they exert on the plate 22 two equal and opposed forces, allowing it to shift forwards or backwards by means of a minimum effort. Each plate 22 has at opposite ends recesses 42 and 43 in which there can be inserted two respective universal bars constituted by two plates 44 and 46 fixed on two shafts 47 and 48 turning in a fixed plate 50 (FIG. 1) of thekeyboard. Fixed on the shaft 47 there is moreover a lever 49 (FIG. 2) connected, by means of a connecting rod 51, to a lever 52 fixed to the shaft 48. The lever 52 carries a small pin 53 collaborating with a slot 54 of the connecting rod 51. The connection between the lever 52 and the connecting rod 51 is completed by a spring 55 stretched between the lever 52 and the connecting rod 5 1.
The lever 49 is provided with a pin 56 which, under the action of a spring 57, normally bears against a cam 58. This is keyed on a main shaft 59 revolving in the frame of the keyboard and adapted to be connected, through a clutch 61 (FIG. 1), to a driving shaft60 for a cycle of 360. The clutch 61 (FIG. 3) is provided with a disengaging tooth 62 nonnally caught by a lug 63 of a lever 64 fulcrumed on a fixed axis 66. The lever 64 is connected by a pin and slot to a lever 67 fixed on a shaft 68 turning in the frame of the keyboard. The lever 67 is drawn anticlockwise by a spring 65. Fixed on the shaft 68 there is moreover a universal bar constituted by a plate 69 which acts normally on a lug 71 (FIG. 2) of each plate 22, keeping this latter rested with a lug against the comb 31.
Keyed on the main shaft 59 there is a cam 72 adapted to collaborate with a lever 73 fulcrumed on a fixed axis 74 and drawn anticlockwise by a spring 76. The lever 73 is connected by a pin and slot to a lever 77 fixed on a shaft 78 turning in the frame of the keyboard. Also fixed on the shaft 78 there is a universal bar constituted by a plate 79 adapted to collaborate with the lugs 70 of the plates 22.
Each plate 22 is provided on its lower long edge with code cams or projections according to the code combination associated with the corresponding key. In particular each of the cams isconstituted by the one or by the other of a pair of teeth 83, 84, the tooth 83 of which is associated with one of the values of a corresponding binary digit, while the tooth 84 is associated with the other value of the binary digit. Each pair of teeth 83, 84 is arranged in correspondence with each of six code bars 86 adapted to assume one of two rotated positions. Each code bar 86 is of substantially rectangular section and is fixed on a corresponding shaft 90 turning in the frame of the keyboard. Each bar 86 is moreover provided with two edges 87, 88, respectively adapted to be thrust downwards by the The slider 95 has a series of arms 1111 provided with small pins 1112 adapted to collaborate with a projection of a corresponding series of levers fixed to the shafts 99, whereby the slider 95 holds the code bars 116 in the position attained. Each lever 1113 is in ferromagnetic material and in correspondence with the two positions of the code bar 811 is adapted to be inserted between a permanent magnet 1114 (FIG. 5) and a pair of reed relay contacts 1116 or removed from between these.
Fulcrumed on the lever 52 (FIG. 3) is a second lever 1117 normally urged against a fixed stop 11111 by the action of a spring 113. The lever 1117 is moreover provided with a lug 1119, which is adapted to collaborate with a stepped profile of a lever 111 fixed on a shaft 112 turning in the frame of the keyboard. The lever 111 is connected to the lever 1117 by the spring 113, which keeps it normally rested against a fixed stop 1111. A ledge 116 of the lever 111 is adapted to be hooked by the upper edge of the lug 1119. The lever 111 is provided moreover with a lug 117 adapted to engage a lever 113 fulcrumed on the shaft 112 and provided with an arm 119 normally urged through the action of a spring 122 on to a lug 121 of the lever 52.
The lever 118 is finally adapted to collaborate with a lug 123 of a slider 124 guided, by means of two slots 126, 127, respectively by a fixed pivot 128 and by the shaft 112. The slide 124 is drawn forwards by a spring 129 and is provided with a lug 131, which is engaged by a lever 132 of the unlocking key 14 of the keyboard. The lever 132 is fulcrumed on a fixed axis 17. Finally, keyed on the shaft 112 is a lever 13 1 (FlGS. 1 and 1) in ferromagnetic material which is adapted to be inserted between a further permanent magnet 136 and a further pair of contacts 137.
The keyboard described functions in the following manner:
Upon the depression of any one whatever of the keys 11, 12, 13, the corresponding lever 16 is rotated clockwise about the fixed axis 17 (F113. 2). The lever 16 shifts the lever 18 upwards and backwards (to the left in F16. 1) but the lever 13, through the action of the spring 19, always remains against the ear 21 of the corresponding plate 22. The step 27 of the lever 18 acts on the corresponding ear 21, shifting the plate 22 backwards in a first movement of prearrangement, until the recesses 42 and 13 engage with the respective universal bars 414 and 16.
Towards the end of the travel of the lever 11', the shoulder 26 which has already been urged against the shoulder 241 of the lever 111, causes the lever 12 itself to rotate until the step 27 disengages from the ear 21 of the plate 22. The depressed key can now be released. in this case the lever 18 and the lever 16 rotate integrally anticlockwise through the action of the spring 19 until the lever 18 rests on the ear 21. The spring 19 now urges forwards the lever 18 which slides on the car 21, while the lever 16 continues to rotate until it is brought up against the stop 23. If, on the contrary, the operator keeps the key depressed, the levers 1b and 111 remain in the position attained. When one then releases the key the lever 16 and the lever 13 return to rest, and the step 27 goes once more into engagement with the ear 21 of the plate 22.
During the movement of prearrangement of the plate 22, the lug 71 thrusts against the universal bar 69 causing it to rotate together with the lever 67 (FlG. 3) against the action of the spring 65. The lever 114 is rotated anticlockwise around the axis as, releasing the tooth 62 and closing the clutch 61 which connects the driving shaft 611 (FIG. 1) to the main shaft 59. The cam 511 (FllG. 2) in a first phase of its rotation allows the lever 49 to rotate clockwise through the action of the spring 57. Consequently the connecting rod 51 shifts backwards and causes the lever 52 to rotate clockwise, which removes the lug 121 from the trajectory of the arm 1119 (F113. 3) of the lever 118. This latter, under the action of the spring 122, rotates an ticlockwise until it rests against the lug 117 of the lever 111. in this position the arm 119 is placed in the return trajectory of the lug 121.
The levers 19 and 52 (PEG. 2) cause the bars 1 1 and 115 to rotate, and these act on the recesses 42 and 43 of the plate 22,
thrusting the plate downwards along a direction perpendicular to that of the prearrangernent displacement. 1n such a way the combination of the teeth 83, 1% present on the plate 22, which already on the prearrangement movement have been brought into correspondence with the code bars 815, position selectively each code bar 116 in one of the two possible positions. Correspondingly the levers 1113 (F168. 1 and 41) integral with the corresponding code bars 86, are selectively inserted or removed from between the relative permanent magnets 1114 and the relative pairs of contacts 1116. Where the lever 1113 is inserted the flux of the magnet 111d is diverted, whereby the contacts 11115 remain open (F113. 6). Where, on the contrary, the lever 1113 is removed, the flux of the magnet 1111 is closed through the two contacts 1116, which are therefore polarized with opposite sign. The contacts 1% are therefore attracted one between the other and are closed, producing a signal at the output of a corresponding electrical circuit not indicated in the Figures. Therefore, following the actuation of the code bars 86, a combination of electrical signals is determined.
Simultaneously the lever 93 rotates clockwise integrally with the shaft 417 and thrusts forwards (to the right in FIG. 4) the slider 95. The pins 1112 move away from the projections of the levers 1113, in order to allow the selective rotation of these levers 1113 and hence of the code bars 816. The lever 93 continuing to rotate clockwise, the lever 92 strikes against the stop 98. Consequently the lever 92 rotates anticlockwise, disengaging the lug 97 from the ledge 99 of the slide 95. This is therefore pulled backwards by the spring 91, holding the levers 1113 in the positions to which they have been set as described above by means of the pins 1112, whereby the code bars 86 are locked in the position attained.
The lever 52 (FIG. 3) rotating clockwise pulls down the lever 1117, the lug 1119 of which through the action of the spring 113 remains always in contact with the stepped profile of the lever 111, until the lug 1119 moves below the step 116. Then the cam 58 causes the lever 19 to rotate anticlockwise. The connecting rod 51 is then shifted forwards and, through the spring 55, reverses the rotation of the lever 52. The lever 1117 is then pulled upwards and, since the lug 1119 is now hooked under the step 116 of the lever 111, this lever rotates clockwise. The lever 111, by means of the lug 117, causes the lever 1111 to rotate clockwise, removing the arm 1 19 from the trajectory of the lug 121 of the lever 52. The lever 52 can now complete its own anticlockwise rotation as far as the position of rest.
When the lever 1117 comes against the stop 198, it commences to rotate anticlockwise, until the lug 109 clears the step 116. The lever 111 is then brought back into its position of rest through the action of the spring 113. Similarly the lever 118 is brought back to rest by the spring 122 and its arm 119 remains hooked on the lug 121.
In the first part of the cycle of the shaft 59, the lever 134 (FIG. 41) rotating clockwise together with the shaft 112 had been removed from the gap between the magnet 136 (FIG. 1) and the contacts 137 which had consequently been closed. The lever 111, returning again to the position of rest as described, reinserts the lever 13 1 between the magnet 136 and the contacts 137, which consequently open. There is therefore produced an electrical signal at the output of a corresponding electrical circuit not represented in the figures which enables the machine to read out the electrical signals generated by the rotation of the code bars 86 at an instant when these have been stabilized by the slider 95.
During the anticlockwise return of the levers 49 and 52, the universal bars 1 1 and 16 (FIG. 2) acting on the recesses 42 and 413 lift the plate 22 up again. Simultaneously the cam 72 causes the lever 73 to rotate clockwise. Hence the lever 77 rotates anticlockwise together with the shaft 78 and with the universal bar 79, which acts on the lug 711 of the plate 22, urging it forwards into the position of rest and thus freeing it from engagement with the universal bars 44 and as. The trajectory of the plate 22 has therefore substantially the shape of a rightangled triangle, the shorter sides of which are traversed respectively during the movement of prearrangement and the movement of actuation, while the hypotenuse is traversed during the movement of return to the position of rest.
The accidental actuation of two keys together causes the shifting backwards of the two corresponding plates 22. These in the manner already described are brought into engagement with the universal bars 445 and 46 and are then thrust downwards. Since the two code combinations represented by the teeth 83 and 8d of the two plates 22 actuated are different one from the other, there will be at least one code bar 86 which is affected both by a tooth 83 and by a tooth 84. It is therefore urged to turn in the two opposed directions, whereby it remains in an intermediate position. The two universal bars 44 and 46, and consequently the levers 49 and 52, therefore remain locked in an intermediate position in which the lever 52 succeeds however in removing the lug 121 from the trajectory of the arm 119 of the lever 118 (FIG. 3), as in the previous case. On the other hand, the lug MP9 of the lever 3107 does not succeed in hooking under the step 116 of the lever lilll.
Then the cam 58 returns to rest the lever 49 and therefore the universal bar 44, substantially as described previously, while the universal bar '79 thrusts forwards the two set plates 22. The two plates 22, through the action of the universal bar 79, are released from the universal bars 44 and 46 and, under the action of the respective springs 32 and 33, return into the upper position of rest. During the return to rest of the lever 49, the lever 1167 no longer raises the lever l 11, whereby there is not produced an electrical signal enabling readout of the electrical signals generated by the rotation of the code bars. The connecting rod 5i returns to rest, while the lever 52 and there fore the universal bar 46 remain locked at a certain point of their travel, since the lug 12B is arrested against the arm 1119 of the lever lid. The relative displacement between the connecting rod 51 and the lever 52 is allowed by the spring 55 which connects them. The universal bar 46 thus arrests the shoulder 41d of the plates 22, impeding the successive depression of a key.
In order now to unlock the keyboard, one depresses the unlocking key 14, which causes the lever 132 to rotate clockwise. This, through the lug 131, causes the sliding to the left of the slider 1243. The lug 123 of this slider acts on the lever H8, causing it to rotate clockwise. The arm N9 of the lever H8 removes itself from the trajectory of the lug 121 therefore allowing the lever 52 under the action of the spring 55 to return into its position of rest. Consequently the universal bar 46 is brought back in correspondence with the recesses 33, whereby the plates 22 are free to be prearranged by actuation of another key.
In a calculating machine the problem sometimes arises of actuating specific groups of keys together. For example, in order to execute an operation on a result stored in a register of the machine it is necessary to actuate both the function key relative to the operation to be efiected and a key which recalls the result from the register.
in particular the function key 13 marked with the symbol C in FIG. l is used to select a specific memory of the machine adapted to contain from time to time a datum value. The key 13C is arranged adjacent to the keys 13 for multiplication and for division marked with the symbols X and and to another two keys 13 marked with the symbols l? and O which command an operation of multiplication and of division with accumulation of the relative results in a given totalizer. Finally adjacent to the key 13C there are arranged a key 13 indicated with the symbol for the calculation of the percentages and a key l3 indicated with the symbol or" command of the entry of the first operand of an operation.
The operations controlled by the keys 13 indicated with the symbols X, 1, P, Q, and can be effected on data entered through the numerical keys ill or else on the datum value contained in the aforesaid memory. in this second case the key BC is depressed together with the key 113 of the desired operation.
To that end, associated with key 13C is a plate E38 (PEG. 6), which is provided with a single tooth 84 in correspondence with the first code bar $6 from the right in FEG. 2. With the keys 13 (FIG. ll) indicated with the symbols X, P, Q, mid there are associated six plates 1139 each of which is provided with a tooth 83 and 34 in correspondence with the code bars S6 (H6. 2) from the second to the sixth, but is deprived of any tooth in correspondence with the first code bar 136.
The simultaneous depression of the key BC with one of the six keys 1133 mentioned above causes therefore the simultaneous shifting of the plate lite and of one of the plates H39. Nevertheless, such a simultaneous selection does not cause the locking of the keyboard as previously described, but causes the positive actuation of all the code bars 86. Therefore, simply by assigning to the operation of each of the six keys and to the joint operation of the key C with the other six keys and to the joint operation of the key C with the other six keys a total of 12 different code combination, these 12 are produced with the use of only seven keys, simplifying both the construction of the machine and the use of this on the part of the operator.
What we claim is:
l. A keyboard for calculating, accounting, teleprinting and like machines comprising:
a plurality of tiltable code bars capable of assuming two stable positions to represent binary code combinations,
a set of depressible keys,
a set of parallel elongated plates associated with said keys and displaceable in two opposite directions, each of said plates being provided with a long edge having code projections thereon for selectively operating said code bars upon actuation of the corresponding said plate, each one of said plates being further provided at each of its two ends with a recess,
a setter connected to each one of said keys and engageable with the associated said plate to displace the associated said plate from a rest position in a first direction substantially parallel to said long edge,
a pair of universal bars engageable with said pair of recesses of the displaced said plate and means cyclically operable by said power means for simultaneously shifting said universal bars upon depression of each one of said keys to move the displaced said plate along a second direction perpendicular to said long edge.
2. A keyboard as claimed in claim l, wherein each said elongated plate is connected at the said two ends to the fixed frame of said keyboard by means of two leaf springs of substantially U shape connected at said two ends to said frame, the two sides of each U being parallel to the said long edge, and the two U"s facing in opposite directions.
3. A keyboard as claimed in claim I, in which said code bars have a substantially rectangular section rotatable around a median axis between said two positions, each of said code bars in moving from one of said positions to the other of said positions traversing a point of parallelism to said long edge, said code projections engaging said code bars to rotate said code bars to one of said two positions when said setter is moved in said second direction.
4 A keyboard as claimed in claim 1, wherein said cyclically operable means comprises:
a pair of levers secured respectively to said universal bars,
a connecting rod pivotally linked to the first of said levers and connected to the second of said levers by means of an elastic joint, and
a first cyclically rotatable cam to position of said levers.
5. A keyboard as claimed in claim 1, wherein said two universal bars are engageable with the displaced said plate to move said plate back to said rest position and wherein said cyclically operable means includes:
a further projection on each one of said plates, and
a third universal bar actuatable by a second cyclically rotatable cam through actuating elements to engage said further projections and to bring back to said rest position the corresponding plate in a direction substantially parallel to the aid long edge, whereby the displaced said plate, after having positioned. said code bars, is restored to said rest position in direction oblique with respect to the said first second directions,
6. A keyboard as claimed in claim ll, comprising for each one of said code bars an associated switch comprising a permanent magnet, a pair of reed relay contacts and a ferromagnetic screen, said ferromagnetic screen being shiftable by the corresponding said code bar to a position interposed between said magnet and said contacts, thus causing the selective opening of said contacts.
7. A keyboard for calculating, accounting, teleprinting and like machines, comprising:
a plurality of tiltable code bars movable between two stable positions to represent binary code combinations, electrical switches controlled by said code bars to produce electrical signals representing said binary code,
a set of deprcssible keys,
a set of setting members associated with said keys, each of said setting members being individually operable at the depression of an associated said key, a plurality of code projections on each said setting member engageable with said code bars for setting said code bars in response to the depressing oi one of said keys,
at least one universal bar cyclically reciprocable to operate during its forward stroke an intermediate member engageable with a readout enabling lever elastically urged to a position of rest, said universal bar during its return stroke o crating said intermediate member to rotate said intermediate member until said intermediate member discngages from said enabling lever, said enabling lever returning thereafter into said position of rest;
and an enabling switch comprising a permanent magnet, 21 pair of rccd relay contacts and a ferromagnetic screen, said ferromagnetic screen being controlled by said readout enabling lever to produce an electrical signal during the return to rest of said enabling lever for enabling the readout of the output signals generated by said electrical switches.
A keyboard as claimed in claim '7, wherein said intermediate member is pivotally secured to said universal bar and includes a latch, said readout-enabling lever being pivotally mounted and provided with a stepped edge engageable by said latch during the return stroke of said universal bar and disengageablc thereby at the end of said return stroke, yieldable means urging said latch and said lever to restore said lever into its rest position when so disengaged and wherein each one of said electrical switches consists of a permanent magnet, reed relay contacts and a ferromagnetic screen, said ferromagnetic screen being shiftablc by the corresponding said code bar in order to be selectively inserted between said magnet and contacts, thus causing the selective opening of the said eontacts.
9. A keyboard for calculating, accounting, teleprinting and like machines, having:
a plurality of tiltable code bars movable between two stable positions to represent binary code combinations, electrical switches controlled by said code bars to produce electrical signals representing said binary code, a set of depressible keys a set of setting members associated with said keys and engageable with said code bars to set said code bars to said positions through a plurality of code projections on each one of said setting members, at least one universal bar cyclically reciprocable to operate during its forward stroke an intermediate member engageable with a readout-enabling lever elastically urged to a position of rest, said universal bar during its return stroke causing said intermediate member to rotate said enabling lever until said intermediate member disengages from said enabling lever, said enabling lever than returnmg to its rest position; said intermediate member pivotally secured to said universal bar and including a latch, said readout enabling lever being pivotally mounted and provided with a stepped edge engageable by said latch during the said return stroke of said universal bar and disengageable thereby at the end of said return stroke,
yieldable means urging said latch and said lever toward the rest position of said lever when so disengaged,
and a locking member capable of locking said universal bar against return to rest after it has moved in a forward stroke, said locking member being rendered ineffective by said readout enabling lever when moved behind its rest position, whereby when actuating at least two of said setting members simultaneously, one of said setting members limits the movements of the universal bar in that at least one of said code bars is pushed in opposite directions, whereby said intermediate member is only partially moved, so as to become ineffective to cause said latch to engage said lcver, the universal bar then hindering prearrangement of further setting member.
lid. A keyboard as claimed in claim 9, comprising at least one additional key arranged adjacent to a group of function keys to facilitate the simultaneous depression of said additional key and one key of the said group, the setting member relative to said additional key and that relative to each one of the keys of the said group having two series of complementary code projections so as to position positively said code bars according to a code combination corresponding to the whole of the functions of the two depressed keys.