US3664478A

US3664478A - Mutual locking device for an office machine with electric keyboard

Info

Publication number: US3664478A
Application number: US68820A
Authority: US
Inventors: Adriano Menicanti; Giacomo Oberto
Original assignee: Olivetti SpA
Current assignee: Telecom Italia SpA; Olivetti SpA
Priority date: 1969-09-16
Filing date: 1970-09-02
Publication date: 1972-05-23
Anticipated expiration: 1989-05-23
Also published as: DE2045613C3; GB1257767A; DE2045613A1; ES383691A1; DE2045613B2; JPS5018806B1

Abstract

In an electric office machine having a keyboard and a cyclic operating mechanism responsive to the keyboard, locking means for preventing the mechanism from operating if two keys are depressed simultaneously until such time as the locking means are released by a motor-driven releasing means consisting of an oscillating member and a release element arranged to be operated by the oscillating member when a release key is depressed.

Description

( 51 May23, 1972 United States Patent Menicanti et al.

Francisco...........................

Na .mwm a d SRS 4577 6666 N999 wmmm 273 205% 559 5994 3333 Oberto, Samore, both of Italy I Primary Examiner-Robert E. Pulfrey Assistant Examiner-Eugene H. Eickholt [73] Assignee: Ing. C. Olivetti & C., S.p.A., Torino, Italy Sept. 2, 1970 [21] Appl. No.: 68,820

AttorneyBirch, Swindler, McKie & Beckett [22] Filed:

[57] ABSTRACT In an electric ofiice machine having a keyboard and a cyclic [30] Foreign Application Priority Data operating mechanism responsive to the keyboard, locking means for preventing the mechanism from operating if two Sept. 16,1969 y are depressed simukaneously um such time as the 197/17, 197/107 locking means are released by a motor-driven releasing means consisting of an oscillating member and a release element ar- |97/107' 17 ranged to be operated by the oscillating member when a release key is depressed.

2 2 M m w B m s11 |m.c|................ 5s

References Cited UNITED STATES PATENTS 2,870,896 1/1959 10 Claims, Drawing Figures MUTUAL LOCKING DEVICE FOR AN OFFICE MACHINE WITH ELECTRIC KEYBOARD BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an electric office machine with a keyboard, such as an electric typewriter, with locking means operative when two keys are depressed together. Upon depression of each key of the keyboard, a cyclic actuating mechanism is operated, to actuate the corresponding type-bar in the case of a typewriter. The locking means are activated upon simultaneous depression of two or more keys in order to prevent further actuation of the cyclic mechanism when other keys are depressed until the locking means are made inoperative by releasing means which are motor-driven and manually set.

2. Discussion of the Prior Art Various machines of this kind are already known. In one known ofiice machine with electric keyboard, the locking means comprise a clutch which is closed for one half-cycle upon simultaneous depression of two keys to effect locking of the keyboard. This clutch is then closed for the other halfcycle upon depression of the release key. This mechanism is complicated and costly.

In another known electric typewriter, the locking means comprise a small lever actuated by a cam of the cyclic actuating mechanism, at a constant speed. The actuating spring of an actuator is dimensioned so as to operate the actuator at a reduced speed when two or more writing mechanisms have been simultaneously connected therewith, thus enabling the small lever to come into the path of the actuator before the latter has actuated the writing operation. This locking means is quite delicate, particularly in the case of an electric typewriter of reduced siie wherein the stresses for entraining the writing mechanisms are comparatively reduced.

In another known typewriter, the locking means comprise a full-cycle clutch, which is closed upon depression of an appropriate key. This'full-cycle is rather expensive and, therefore it is not suitable for a portable typewriter.

SUMMARY OF THE INVENTION The object of the present invention is-to avoid the disadvantages enumerated above.

In accordance with the present invention, there is provided an electric office machine comprising a keyboard, a cyclic actuating mechanism arranged to be operated when each key of the keyboard is depressed, and locking means adapted to be activated upon simultaneous depression of two or more keys in order to prevent further actuation of the cyclic mechanism when other keys are depressed, until such time as the locking means are rendered inoperative by motor-driven releasing means. The motor-driven releasing means comprise a powered, continuously oscillating member and a release element arranged to come into engagement with the oscillating member when a release key is depressed, to be moved thereby to render the locking means inoperative.

According to another feature of the invention, the locking device is applied to an electric typewriter wherein each writing mechanism or key comprises a strut pivotally mounted on an intermediate lever cooperating with the corresponding lever of the key, the various intermediate levers being pivotally mounted on a first common shaft or axis disposed behind the keyboard, the various key levers being pivotally mounted on a second axis disposed in front of the keyboard, and the motor shaft being disposed between said two axes and slightly beneath the plane passing through them, so as to obtain a compact arrangement of considerably reduced height.

DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, one particular embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, wherein:

DESCRIPTION OF A PREFERRED EMBODIMENT The typewriter keyboard 1 (FIG. I) comprises a plurality of key levers 2, each of which has one end 3 pivotally mounted on a front bar 4, while the opposite end 5 isprovided, at the top, with a projection adapted to receive a key 6 and, at the bottom, with a projection 7 adapted to cooperate with a transmission lever 8. Each key lever 2 is further provided with a finger 11 arranged for engagement in a slot 12 of a lower comb 13 a frame of the keyboard, while the end 5 of the lever 2" sses through a slot 14 in an upper comb 15 of the same frame. The finger ll, cooperating with the slot 12, and the end portion 5, cooperating with the slot 14, guide the lever 2 during its-pivotal movement around the bar 4. Each key lever returns until a flat support seat 16 on the end 5 of the lever bears against a pad 17 made of a suitable soft material on the underside of a top plate 18 which encloses the mechanism beneath the keys 6.

Each transmission lever 8 is pivotally mounted on a rear bar 19 and comprises a first arm 20, against whose upper end the projection 7 of the end 5 of the key lever 2 bears, and a second arm 21 whose end is resiliently connected to a plate 22. This plate 22 is pivoted on the lever 8 by a pin 23 and is provided with a slot 24 adapted to cooperate with a pin 25, with a cer- 35 tain backlash. A coil spring 26, biased between a projection of the arm 21 and the plate 22, normally holds the latter rotated upwards, as seen in the drawing.

Two fingers 28 and 29 of the lever 8 enter into slots 30 and 14 in the lower comb l3 and the upper-comb 15 respectively and guide the pivotal movement of the lever about the rear bar 19. A coil spring 32 tensioned between the comb l3 and the finger 28 of the lever 8 holds the arm 20 of the lever 8 against the projection 7 of the key lever 2, while pushing the support seat 16 of this lever against the pad 17.

The writing mechanism or kinematic linkage shown in FIG. I comprises an intermediate lever 35 which is .pivotally mounted on a bar 36 integral with the typewriter frame and drives, through tie rods 37 and a bell-crank lever 38, a type bar with type 39. Each lever 35 is urged to its rest position, as shown in FIG. 1, by a coil spring 40 tensioned between the lever and a projection 42 of a plate 43.

Two

pins

44, 45 of each intermediate lever 35 have respectively pivoted thereon a lever 46 with a hook and an entrain ment lever 47 provided with a small tooth, these levers being connected together by a coil spring 48. In the position of rest shown in FIG. 1, the

levers

46 and 47 are engaged, as seen in the drawing, because the spring 48.biases the lever 46 so as to hold its hook over the small tooth of the lever 47. Each intermediate lever 35 is disposed, with respect to the corresponding lever 8, in such position that a front lug 50 of the lever 46 is in the path of the plate 22 of the lever 8. Further, a projection 52 of the lever 47 is adapted to strike against a coupling control flag 53 which can rotate about a bar 54 integral with the machine frame.

Y A hook 55 of the entrainment lever 47 is adapted to be entrained by a projecting part 56 of a writing-control flag 57 integral with a spindle 58 rotatably mounted on the machine frame.

The typewriter is further provided with a cam assembly 60 (FIG. 1), which can be rotated by a motor shaft 61 when a coupling or clutch 62 is engaged. This coupling 62 essentially comprises a sprocket wheel 63, a plate 64 mounted idle relative to the shaft 61 and biased by a spring 65 (one of whose ends is fastened to a pin 66 integral with the cam assembly 60) and provided with a pair of spurs 67 diametrically opposite to one another and, finally, a hook 68 hinged to the cam assembly 60 at 70 and provided with a pin 71 guided in a slot 72 disposed obliquely in the plate 64. In the rest position, as shown in FIG. 1, the coupling 62 is normally held open by the action of a lug 73 of a bail 74, which lug is disposed against the spur 67 shown at the top in the drawing. When the extension 73 is removed from the spur 67, in a manner to be described below, the plate 64, under the biasing action of the spring 65, will be caused to rotate relative to the cam assembly 60 and, during this rotation, the obliquely disposed slot 72 will displace the pin 71, thereby causing the hook 68 to rotate, until it is brought into engagement with the teeth of the sprocket wheel 63, so as to render this sprocket wheel, and therefore the shaft 61, integral with the cam assembly 60.

The cam assembly essentially comprises three

cams

60,, 60 and 60 The cam 60 has two projecting parts 75, substantially offset by 180 from one another, and is adapted to cooperate with a small roller 76 integral with a lever 77 which can rotate about a spindle 78. One arm of this lever actuates, through-a connecting rod 80, a crank 81 which is integral with the spindle 58 of the writing-control flag 57. When the small roller 76 of the anchor 77 cooperates with a projecting part 75 of the cam 60,, the writing-control flag 57 is in the position of rest shown in FIG. 1. A spring 82 biases the flag to rotate in the direction of the arrow in FIG. 1.

The cam 60 (FIGS. and 3) cooperates with a spur 83 of the bail 74 which, like the lever 77, is also rotatably mounted on the spindle 78 and is normally held in the rest position (corresponding to the disengaged position of the coupling 62) shown in the drawings, by a spring 84 which biases a tongue 85 of the bail 74 against a projection 86 of a frame 87. This frame is adapted to rotate about a spindle 88 and is actuated by the coupling-control flag 53. The frame 87 is held in the rest position (shown in FIGS. 1 and 3) by a spring 90.

The cam 60 (FIG. 1), with the corresponding follower arm 92 biased by a spring, is merely a positioning cam.

The typewriter described is provided with a locking device which, upon simultaneous depression of two keys of the keyboard and after a writing cycle has been started, prevents the corresponding types of the type bars 39 from coming against the platen of the typewriter and also prevents starting of a subsequent writing cycle by locking the coupling or clutch 62. Release of the coupling 62 and resetting of the rest condition, corresponding to the starting of one cycle, are attained by depressing an appropriate key provided on the typewriter.

The device described comprises locking means for preventing movement of more than one intermediate lever 35, known per se, Such means comprise, for instance, a plurality of balls 92a (FIG. 1), disposed inside a guide 93 which is closed at its ends. The length of this guide, as well as the number of the balls and the size of the latter, are so chosen as to provide a slight clearance between the balls, sufficient to permit the passage of one spur 94 formed on the lower side of each intermediate lever 35. Therefore, when only one of these levers is pivoted, upon actuation of a key 6 of the keyboard, in a manner to be described below, the spur 94 will be inserted between two adjacent balls 92a, thereby taking up the clearance normally existing between them and allowing the lever 35 to perform a complete revolution, sufficient to bring the corresponding type 39 against the platen of the typewriter. When, instead, two keys are simultaneously depressed, the clearance existing between the balls 92a is insufficient to allow passage of the pair of spurs 94 corresponding to the two levers 35, so that these levers will be able to perform a small stroke only, not sufficient to bring the types against the platen of the typewriter.

The locking device embodying the present invention comprises further means for locking the coupling or clutch 62, which means comprise a locking frame 95 (FIGS. 1 and 3) and a lever 96 which is integral with a control shaft 97.

The locking frame 95 is rotatably mounted on the spindle 88 (FIG, 3) and is provided with a lug 98 (which is shown in FIG. 3 only, having been omitted from FIG. 1 for the sake of clarity) as well as with a locking tooth or detent 100 and carries, in its upper portion, a small plate 101 pivotally mounted thereon at 102. The plate 101 is provided with a catch 103 (which is normally held against a bent portion of the frame by the action of a coil spring 104) and with a projection 105. In its rest position, the frame 95 is pushed against the tongue 85 of the bail 74 by the spring 106. In this position, the detent is not engaged beneath the tongue 85, but the frame 95 stops against the tongue.

The lever 96 is provided with a projection 107 which, in the rest position, is held against an arrest bar 110 by a spring 108,v and is further provided with a lug 111 adapted to interfere with the projection 105 of the plate 101 when the lever is pivoted in counterclockwise direction. The projection 105 is so shaped as to allow the lug 111, following the pivotal movement of the lever 96, to pass beyond the projection, thereby causing the plate 101 to rotate in counterclockwise direction, whereas, when said lever is pivoted in the opposite direction, the lug 111 comes into engagement with the underside of the projection 105, thereby rotating the frame 95 until, after a certain pivotal movement of this frame, the lug 1 11 disengages from the projection 105.

The pivotal movement of the frame 95 in counterclockwise direction can also be brought about by the action of a spur 1 12 integral with the lever 77, which bears against the lug 98 of the frame.

The rotation of shaft 97, which is integral with the lever 96, in the direction of the arrow shown in the drawing, is brought about by actuating means forming part of the locking device which can be activated upon depression of a key of the keyboard. These actuating means are illustrated in FIG. 4 and comprise an oscillating member 113 provided with a lug 114, which is adapted to oscillate continuously about a shaft 1 15 by the action of a cam 116 integrally fastened to the motor shaft 61 (FIGS. 1 and 4) continuously rotating in a predetermined direction. A bell-crank lever 118, pivotally mounted on the machine frame at 119, is provided with a small roller 120 and is connected by means of a connecting rod 121 to a crank 122 of the oscillating member 1 13.

To the shaft 97 is secured a crank 123 which is further pivotally mounted, by means of a pin 124, on an engagement lever or pawl 125 provided with a hook or end tooth 126. The engagement lever is held in its position of rest, relative to the crank 123, by a spring 127. The lever 125 is caused to rotate, in clockwise direction, by a control lever 128, which is pivotally mounted on the rear bar 19 (FIGS. 1 and 4) of the typewriter. Contacting the end 139 of the lever 128, is a projection 131 of a lever 132 which is integral with a key 133 and pivoted on the front bar 4 (FIGS. 1 and 4) of the machine. In the embodiment illustrated in FIG. 4, the lever 128 when it rotates the lever 125 acts upon a lug 135 of the lever or pawl 125 through a small plate 136 resiliently secured to the lever 128 by means of a spring 137.

It should be noted that the

levers

132 and 128 are pivotally mounted on the same front bar 4 on which the key levers 2 are pivoted (FIG. 1) and on the same rear bar 19 on which the levers 8 are pivotally mounted, and since the shaft to which the cam 116 is integrally fastened is the same motor shaft 61, the constructional arrangement of the actuating means just described is highly compact and such as to enable a typewriter of considerably reduced height to be obtained. To this end the shaft 61 lies between the bars 4 and 19 and somewhat below the plane passing through these bars.

The shaft 97 is integral with a plate 138 (FIG. 4), which is disposed in correspondence with the rear projections 52 (FIG. 2) of the levers 47. When the

levers

46 and 47, corresponding to an intermediate lever 35 have been disengaged, the projection 52 comes in proximity with the plate 138.

The operation of the locking device is as follows. Assume first that initially only one key 6 (FIG. 1) is depressed. The key lever 2 will then pivot about the bar 4 and the projection 7 of the end 5 of the lever, by pressing upon the first arm 20 of the transmission lever 8, will cause this lever to pivot about the bar 19. As a result of this pivotal movement, the upper end of the small plate 22 acting as a strut is pushed against the front lug 50 of the lever 46, thereby displacing this lug 50 upwards, as seen in FIG. 1, and disengaging the hook of the lever from the small tooth of lever 47, which is rotated in counterclockwise direction, as seen in FIG. 2. The outer profile of the projection 52, by cooperating with the coupling-control flag 53, will cause the latter to rotate in clockwise direction (FIGS. 1 and 2), thereby rotating the frame 87 (FIGS. 1 and 3), whose projection 86 will disengage the tongue 85 of the bail 74. This bail acts as the clutch control member and will rotate in clockwise direction (FIG. 3) under the action of the spring 84', thereby lifting the lug 73 from the spur 67 of the plate 64 ofthe clutch 62 (FIG. 1

As a result of lifting of the lug 73 (FIG. 1), the clutch 62 is closed in the manner already described previously, and the cam assembly 60 is rendered integral with the motor shaft 61. During the first stage of rotation of the cam assembly 60, the cam 60,, by cooperating with the small roller 76, will impart a first rotational movement, through the lever 77, the connecting rod 80 and the crank 61, to the shaft 58 and, therefore, to the writing-control flag 57 (in counterclockwise direction, as seen in FIG. 1 thereby bringing the protruding part 56 of the flag in proximity of the hook 55 of lever 47, already disengaged previously. Upon further rotation of the cam 60, the small roller 76 will clear the protruding part 75 of the cam 60,; thus, the lever 77 is no longer controlled by this cam, whereby the rotation of the writing-control flag 57 will continue solely under the action of the spring 82, this flag constituting a common actuator for' the mechanism associated with each key. During this second stage of rotation, the writing-control flag, with its projecting part 56 cooperating with the hook 55, causes the intermediate lever 35 to rotate (in counterclockwise direction, as seen in FIG. 1), and this lever will bring the type of the type bar 39 against the platen of the typewriter. During the pivotal movement of the lever 35, the spur 94 of this lever can easily enter between the balls 92, on account of the clearance existing between them.

During the rotation of the cam assembly 60 and in the period of time when the aforementioned rotation of the writing-control flag 57 takes place, the spur 83 of the bail 74' (FIGS. 1 and 3), by cooperating with the cam 60,, will cause the bail to rotate in counterclockwise direction, thereby lowering the lug 73 (FIG. 1) of the bail in order to insert this lug in the path of the spur 67 which is shown in its lowermost position in FIG. 1, and which, following 180 rotation of the cam assembly 60, is brought in proximity of the lug 73. In this manner, the clutch 62 is opened and the cam assembly 60 is arrested. A complete revolution of the cam assembly 60 will correspond to two writing cycles.

During the revolution of the cam assembly 60, that is to say during the rotation of the lever 77 (FIG. 3), the spur 112 of the lever will act against the lug 98 of the locking frame 95, thereby causing this frame to rotate, in clockwise direction as seen in FIG. 3, and therefore displacing the detent 100 from the tongue 85 of the bail 74. In this manner, during a normal writing cycle started upon depression of a single key of the keyboard, the aforementioned locking means of the clutch shown in FIG. 3 are rendered inoperative by the rotation of the locking frame 95.

The intermediate lever 35 (FIG. 1) is brought back to its rest position by the action of the coil spring 40, whereas the coupling-control flag 53, with the corresponding frame 87, are brought back to their position of rest by the action of the coil spring 90.

Assume now that two keys 6 of the keyboard are depressed simultaneously. The end of a pair of small plates 22 will then lift a corresponding pair of front extensions of levers 46, thereby disengaging the corresponding levers 47. Since, in this instance, simultaneous pivotal movement of a pair of intermediate levers 35 takes place, the corresponding spurs 94, on account of the foregoing, cannot penetrate between the balls 92 but will come to rest against the same, thereby allowing said lever to perform a small rotation only.

As in the case of depression of a single key, following rotation' of the flag 53, the projection 86 will clear the lower surface of the tongue of the bail 74, thereby disengaging this bail and starting, as in the preceding instance, the closure of the clutch 62 and the beginning of a new cycle. However, in this case, as contrasted with the preceding instance, since the intermediate levers 35, corresponding to the two keys which have been depressed, have performed only a short stroke, the hooks 55 of the levers 47 will engage the protruding part 56 of the writing-control flag 57, thus locking it, after this flag has accomplished a small movement of rotation, under the action of the profile of the protruding part 75 of the cam 60,. The lever 77 is also locked, and, since its spur 112 cannot act against the lug 98, the locking frame will not clear the tongue 85 of the bail 74. After a given rotational movement of the cam assembly 60, the spur 83 (FIG. 3) of the bail 74, by cooperating with the cam 60,, will cause the bail 74 to rotate in counterclockwise direction, whereby the detent of the locking frame 95 will snap beneath the tongue 85, thus locking the clutch for the subsequent cycle.

In this manner, upon simultaneous depression of two keys, besides preventing the corresponding types of the type bars from reaching the platen, starting of a new cycle is also prevented.

In order to re-engage the clutch, the key 133 must be depressed (FIG. 4); this can be a special key provided for this purpose or may be a key actuating another function of the typewriter also, for instance the margin release key. As already stated, depression of this key will cause pivoting of the control lever 128 in a counterclockwise direction and therefore lifting of the engagement lever or pawl 125, whose end hook 126 is brought in the path of the lug 114 of the oscillating member 113. This lug 114, during its oscillation leftwards, as seen in FIG. 4, will impart to the lever a traverse movement in the same direction, thereby causing rotation of the crank 123 (in counterclockwise direction) and of the shaft 97 to which the lever 96 is integrally fastened (FIG. 3). During the pivotal movement of the lever 96, the lug 111 is caused to rotate (downwards, as seen in FIG. 3), thereby rotating (in counterclockwise direction, as seen in FIG. 3) the plate or second pawl 101 relative to the frame 95. The lug 111 will then rotate, with the lever 96, in the opposite direction by the action of the spring 108, and during this rotation, it will come in engagement with the projection 105, rotating the frame 95, because the plate 101, during this rotation, is rendered integral with the frame by the catch 103 cooperating therewith. In this manner, the detent 100 is removed from the lower face of the tongue 85 of the bail 74 and the conditions prevailing at the start of a normal writing cycle are restored. The lug 111 and pawl 101 act as a one-way coupling.

Since the lever 125 is lifted by the resiliently movable plate 136 on the lever 128 it does not matter where, in the cycle of the oscillating lug 114, the key 133 is depressed.

The

levers

46 and 47 are re-cocked in a normal writing cycle, corresponding to the depression of a single key of the keyboard, during the last part of the stroke of the intermediate levers 35. When, instead, the writing cycle is started upon depression of two keys, the re-cocking cannot occur as in the preceding case, since the intermediate levers perform only a short stroke. In this instance, re-cocking is accomplished by the plate 138 (FIGS. 2 and 4) which, upon depression of the key 133 (FIG. 4), is caused to rotate, together with the shaft 97, by the lever 125, and brought into cooperation with the rear profile of the projections 52 of the levers 47 (FIG. 2).

We claim:

1. An electric office machine comprising a keyboard a cyclic actuating mechanism operated when each key of said keyboard is depressed,

locking means actuated by the simultaneous depression of two or more keys to prevent operation of said actuating mechanism, and

motor-driven lock release means for releasing said locking means, said release means comprising a powered, continuously oscillating member, a release element engageable by said oscillating member and operatively connected to said locking means to release said locking means when engaged by said oscillating member, and a release key operatively connected to said release element for moving said release element into the path of said oscillating member when said release key is depressed.

2. An electric office machine according to claim 1 wherein said release element is a pivotally mounted first pawl, the depressing of said release key causing said first pawl to pivot into the path of said oscillating member to be engaged thereby.

3. An electric office machine according to claim 1 wherein said oscillating member is driven continuously by a multiplelobe cam.

4. An electric office machine according to claim 2, wherein a common actuator performs a forward stroke by the action of a spring in order to actuate a mechanism associated with each depressed key, and a return stroke by the action of the cyclic actuating mechanism, which is actuated through a coupling closed when a control member is released upon depression of the key, the locking means comprising a detent which is adapted to temporarily engage the control member in a locked position during each cycle, the common actuator disengaging the detent at the end of its forward stroke, the stroke of the common actuator being shortened when two keys are depressed simultaneously so that the detent leaves the control member in the locked position, the release element being coupled to the detent to disengage the detent when the release element is moved by the oscillating member.

5. An electric office machine according to claim 4, wherein the release element disengages the detent through a second pawl pivotally mounted on a member carrying the detent, and engaging portion integral with the member on which the first pawl is pivotally mounted being adapted to coact with the second pawl so as to disengage the detent during one forward or return stroke of the last said member.

6. An electric office machine according to claim 5, wherein the second pawl is connected with the last said member by means of a one-way coupling such that the engaging portion, during its forward stroke, snaps past the second pawl, whereas during the return stroke, actuated by a spring, it will displace the second pawl and the member carrying the detent through the one-way coupling.

7. An electric office machine according to claim 6, wherein the common actuator comprises an oscillating flag and each said mechanism associated with each depressed key comprises a type mechanism of a typewriter including type bars and an intermediate lever with one arm connected to the type bar and individually engageable with the flag, the flag being prevented from reaching the end of the forward stroke by prematurely arresting the intermediate levers with arrest means acting upon the intermediate levers when at least two of these leve have been engaged by the flag.

8. An electric office machine according to claim 7, wherein arrest means comprise a set of balls disposed in the path of portions of the intermediate levers opposite to the one arm and adapted to allow displacement of only one intermediate lever at a time.

9. An electric office machine according to claim 8, wherein each intermediate lever is engaged with the flag by means of an entrainment lever pivotally mounted on the intermediate lever and normally held in the inoperative position by a hook also pivoted on the intermediate lever and adapted to disengage the entrainment lever upon depression of the corresponding key, the release element being coupled to a universal bar which, upon actuation of the release element, engages a portion of the disengaged entrainment levers, thereby re-engaging these levers with the corresponding hooks.

10. An electric office machine according to claim 9, wherein each hook is actuated by a corresponding strut for disengaging the entrainment lever, (each strut being pivoted to an intermediate lever cooperating with the corresponding key lever, the various intermediate) each type mechanism also comprising another intermediate lever pivotally mounting the corresponding strut and a key lever secured to the corresponding key and cooperating with said other intermediate lever, all said other intermediate levers being pivotally mounted on a first common axis disposed at the back of the keyboard, (the various) all said key levers being pivotally mounted on a second axis disposed in the front of the keyboard, and a motor shaft for driving the cyclic mechanism and the oscillating member being disposed between the said two axes and below the plane passing through them.

l I k 1B

Claims

1. An electric office machine comprising a keyboard a cyclic actuating mechanism operated when each key of said keyboard is depressed, locking means actuated by the simultaneous depression of two or more keys to prevent operation of said actuating mechanism, and motor-driven lock release means for releasing said locking means, said release means comprising a powered, continuously oscillating member, a release element engageable by said oscillating member and operatively connected to said locking means to release said locking means when engaged by said oscillating member, and a release key operatively connected to said release element for moving said release element into the path of said oscillating member when said release key is depressed.

3. An electric office machine according to claim 1 wherein said oscillating member is driven continuously by a multiple-lobe cam.

7. An electric office machine according to claim 6, wherein the common actuator comprises an oscillating flag and each said mechanism associated with each depressed key comprises a type mechanism of a typewriter including type bars and an intermediate lever with one arm connected to the type bar and individually engageable with the flag, the flag being prevented from reaching the end of the forward stroke by prematurely arresting the intermediate levers with arrest means acting upon the intermediate levers when at least two of these levers have been engaged by the flag.