US2073902A - Noiseless typewriter - Google Patents

Description

March 16, 1937 OUVETT. A 2,073,902

NOISELES S TYPEWR I'I'ER Filed Oct. 3, 1935 2 Shets-Shet 2 lNVENTOR CAMILLO OLIVETTI 7 B I 0&2 I

' AT ORNEV Patented Mar. 1.6, 1937 HPATENT OFFICE" 'ap'lasoz NOISELESS Camille Olivetti, lv'rea, Italy Application ottom- :i, 1935, erial No. 43,438

In Italy October 2'1, 1934 9 Claims. (01. rev-22) It is well known that one of the greatest difflculties usually met in the construction of noiseless typwriters lies in the necessity of giving a ate the type levers, in order not to lose in the elastic deformation of these parts a considerable amount of the *power available for the writin operation, thus lowering the efficiency of the typewriter. I

My invention involves a new principle, whereby, at the moment of printing,'the paper carrying platen is advanced and pressed against the type, The platen is advanced to the position in which a print is made by means of a kinematic mechald nism so designed that, when the key on the keyboard is pressed, thespeed of the type lever will be gradually reduced to zero and the type will be held firmly against the moving platen until the print is accomplished.

2.0 The operation andthe advantages of a typewriter embodying my invention will be better.-

understood by considering the following:

If the paper carrying platen were extremely light, it would be necessary to impart to it a very of sufficient magnitude to equalize the printing work. This manner of operating would be substantially the same as takes place inthe prior art typewriters, though obtained by a wholly different mechanism. If, on the contrary, the,

a proper choice of the weight of the paper carrying platen a suflicient kinetic energy can be imparted to it even with a low speed or a short motion, and that the approaching speed of the platen can be held within so small a limit that, the noise resulting from the stroke will be extremely reduced.

A further advantage of the present invention will be found considering that, as will be better explained, itis possible to regulate within ample limits the time during which the paper is pressed against the type; moreover, this fraction of time will be longer than in the prior art models, withv out in the least lowering the typing speed. Also, the print is substantially improved, as it is well known that the longer the pressure the greater 55 the quantity of ink transferred from the ribbon marked rigidity to the movable parts which actuthe type firmly when thepaper high speed in order to obtain a kinetic energy' (placed as usual between the type and the paper) to the paper.

While the following specifications and the-accompanying drawings show an embodiment of the present invention, it is apparent that any other device which will perform on the above-mentioned principle may be regarded as suitable.

As'will be better explained later, the paper carrying platen is actuated by means of a. spring which is loaded, every time a print is made, by the so called universal bar. Therefore, it is the pressure of the typists finger on the key which causes the forward motion of the paper carrying platen; however, this motion can be obtained in many other ways. I

The type bar mechanism may be varied too; as a matter of'fact, any kind of connection will be suitable if capable of slowing down the motion of the type when the latter approaches the position 'in which a print is to be made and holding carrying platen is pressed against-it. I

In the accompanying drawings; Figure 1 is a. fragmentary sectional view showing the type bar mechanism in the position 1 of rest;

Fig.2 is a similar view showing the type bar mechanism in the printing position;

Fig. 3 is a'similar view showing the type ha mechanism in the position in which a print is not yet made but the type bar is held standing while the platen is beginning its forward motion; and r Fig. 4 and 5 are detail views of the linkage used to determine the forward motion of the platen.

With reference to Fig. 1, the key lever l is pivoted at 2 and, through lever 3 pivoted at I, rocks lever 5 about its fulcrum B.- The end of lever 5 carries a stud I slidably positioned in a slot 8 cut in the lever 9 pivoted at Ill. The slot 8 is so designed in correspondence with the operating lever 5 that the speed of lever 9, very slow at the beginning of its stroke, is evenly accelerated as the stud 'l approaches the hearing or pivot ll) of the type lever 9, again reduced as the. stud moves away from pivot l0 and flnally stopped in the printing position when the longi-J 'tudinal axis of the slot is tangent to the circle described by the stud I. It will be noted that in this position a further pressure on the key will only hold the type still, without effecting a backward movement of the type. Consequently, this structure will easily withstand the thrust from the paper carrying platen.

The platen is fixed to the frame |2 of the carriage by means of a parallel linkage composed of two cranks l3 and H and a T-shaped connecting rod l5 which will restrict motion of the 5 platen 'to a horizontal direction, perpendicular to the axis of the platen. A slot 31 is formed in the upper vartical portion of connecting rod l5 which provides a bearing for the shaft of the paper carrying platen so that the latter can assume a vertical motion, whereby each one of the types carried by the type lever can strike on the platen.

A bar linkage of this type is provided at both ends of the paper carrying platen and the two connecting rods or bars l5 are coupled together by a rod l6 of the same length as the platen. This rod I6 is engaged by a forked lever pivoted at l6 which serves to impart to the paper carrying platen a small transverse motion toward and away from the type without interfering with the lateral shift of the whole carriage. A spring l9 urges lever against a stop 20 and the platen toward the position in which a print will be made. The type levers 9 are cam-shaped in the proximity of their bearing, so that they can operate the universal bar 2|. As is well known, the

universal bar actuates the escapement and the For this operation, any suitable mechanism can be used. In the mechanism shown in -the drawings, lever I1 is controlled by a toggle linkage composed r two links 22 and as. Link 22 is piv- 40 otally connected to the end of lever l1 and link 23 is pivoted on the frame at 24. Link 23 is forkshaped at one end (see Figs. 1 and 5) and supports (in the proximity of, and perpendicularly to, shaft 26) a swinging lever 26 provided with 45 two lugs 21 and 28. Lever 26 is pivotally mounted on stud 25 so that lugs 21 and 28 may alternatively be shifted to register with two other lugs 29 and 36 provided on the moving plate 3|. Cranks 32 and 33 are pivotally mounted at their 50 lower ends to the frame of the machine and carry at-their upper ends the plate 3|. Motion is imparted from the universal bar 2| to plate 3| by means of a rod 34 and a lever 35 pivoted at 36.

55 Fig. 4 represents a front view of the swinging lever 26 and shows a section of the lugs 29 and 36 of plate 3|.

In the position of rest, as shown in Fig. 1, the links 22 and 23 are out of alignment and lug 21 60 on the swinging lever is opposite lug 29 of plate 3|. When plate 3 actuated by the universal bar, advances, lug 29 engages lug 21 and compels link 23 and the swinging lever 26 to revolve around stud 24. The two links 22 and 23 are now in 65 the same line, as shown in Fig. 3, and they compel lever H to rotate ina clockwise direction around bearing l8, loading the spring I9 and shifting the paper carrying platen to a position away from the type.

70 Upon further motion of the universal bar and the consequent advance of plate 3|, the toggle links 22 and 23 pass over their dead center position and lever I1 is permitted to rotate counterclockwise under the action of spring l9, bringing 75 the whole system in the position shown in Fig. 2

and pushing the paper carrying platen against the type, as the type lever 9 has in the meantime reached its final position. An impression is made and spring 39, pulling on lever 5, causes it to rotate clockwise to return the type lever mecha- 5 nism to its rest position, while spring 36 returns the universal bar and all the parts connected to it to their rest position.

On account of the sudden swinging of links 22 and 23, the lug 21 of swinging-lever 26 is disl0 engaged from lug 29 of plate 3| and lug 28 is shifted to a position alongside of'lug 36 which it retains until plate 3| is returned to the rest position together with the universal bar.

'At the next stroke, in order to obtain the same 16 movement of the various parts it is necessary that lug engage against lug 28 of swinging lever 26. Therefore, lever 26 must be shifted to move lug 28 into the path of travel of lug 36, while lug 21 must be moved to a position out of 20 the path of travel of lug 29. This is effected by a small leaf spring 4| horizontally fixed on the typewriter frame at 42. Its free end is engaged between two studs and 36 provided on arm flofthe swinging lever 26; the latter, as already 25 stated, is pivoted at 25 on the fork-shaped extremity of rod 23. The leaf spring is also engaged between two studs 43 and 44 provided on link 22. When the links 22 and 23, which compose the toggle linkage, are shifted upwards or 30 downwards, the leaf spring is bent in the same direction and actuates, through studs 46 and 46, the swinging lever in such a way that lug 2'! will be in the path of lug 29 when the linkage is shifted upwards, while lug 28 will be in the path 35 of lug 36 when the linkage is shifted downwards.

When the toggle linkage, during the operation of the typewriter, suddenly alters its position, the elasticity of the spring 4| allows the lugs 21 or 28 of swinging lever 26 to slide laterally on plate 3|, thus taking the right position with regard to the path of travel of plate 3| when the return stroke is nearly completed.

As already stated, the above-described mechanism isonly one of the many mechanisms for carrying out the present invention.

The forward motion of the paper carrying platen is, in the described example, obtained through the links 22 and 23 by means of the thrust of spring l9 in such a way that the acceler- 50 ation of said platen is positive. With other sys: tems, this acceleration may be negative or even zero, i. e., the paper carrying platen will advance with a constant speed.

The different ways of eflecting this mechanism are to be determined with reference to the weight of the platen, in correspondence with the various characteristics which it is desired that the typewriter possess. This may preferably be eminently dynamic (corresponding to a quick mo- 00 tion of the paper carrying platen) or eminently static (low motion of the platen, but high thrust between paper and type) in consequence of which the typewriter will be more or less noiseless with reference to other characteristics.

Anyway, it shall be understood. that my invention is based on the simultaneous movement of a type bar mechanism which will bringthe type into the printing position with a reduced motion and hold it firmly for a fraction of time while another mechanism, controlled by the universal bar which is pressed by the typist, serves to push forward the paper carrying platen to press it against the type.

Incidentally, it should be noted that the initial I position of the P p r rryi platen may be .16

possessing a residual speed, or just when the type is standing still, or even when it has already begun its backward motion. In the latter case,

the action of printing is effected through the differential speed of the type bar and .the paper carrying platen.

I claim:

1 In a typewriter of the character described. a plurality of type, means for advancing the type to a printing position, a platen shiftable toward and away from the printing position of the type, and means operable upon advancing the type from a position of rest to the printing position to shift the platen away from the printing position and then advance the same to the printing position to engage the type.

2. In a typewriter of the character described, a plurality of type, means for advancing the type to a printing position, a platen shiftable toward and away from the printing position of the type, and means including a toggle linkage operable upon advancing the type from a position of rest to the printing position to shift the platen away from the printing position and then advance the same to the printing position to engage the type.

3. In a typewriter of the character described, a plurality of type, means for advancing the type to a printing position, a platen shiftable toward and away from the printing position of the type,

. resilient means urging said platen to the printing position, and means operable upon advancing the type to the printing position for shifting the platen away from the printing position and allowing it to return under the action of the resilient means. t

4. In a typewriter of the characterdescribed, a plurality of type, means for advancing the type to a printing position, a platen shiftabie toward and away from the printing position of the type, resilient means urging said platen to the printing position, and means including a toggle linkage operable upon advancing the type to the printing position for shifting the platen away from the printing position and allowing it to return under the action of the resilient means.

5. In a typewriter of the character described, a plurality of type bars, means for advancing the type bars to a printing position, a "platen shiftable towards and away from the type of the type bars when the latter are in printing position, re silient means urging said platen toward the printing position, a universal bar actuated by the type bars, and means actuated by said universal bar for shifting the platen away from theprinting position during advance of the type bars, to the printing position and allowing the same to return under the action of the resilient means when the type bars arrive at the printing position.

6. In a typewriter of the character described, a plurality of type bars, means ior'advancing the type bars to a printing position, a platen shiftable towards and away from the type of the type bars when the latter are in printing position, resilient means urging said platen toward the printing position, a universal bar actuated by the type bars,

and means including a toggle linkage actuated by said universal bar for shifting the platen away from the printing position during advance of the type bars to the printing position and allowing the same to return under the action of the rosili- I ent means when the type bars arrive at the printing position.

7. In a typewriter of the character described, a plurality of type bars, means for advancing the type bars to a printing position, a platen shiftable towards and away from the type of the type bars when the latter are in printing position, resilient means urging said platen toward the printing position, a universal bar actuated by the type bars, a toggle linkage comprising a pair of connected links, the first of which has its free end connected to the platen and the second of which has its free end mounted on a stationary pivot, and means actuated by said universal bar during advance of the type bars to a printing position for shifting said linkage from a position wherein the links are at an angle to each other through a' position wherein the links are aligned, to move the platen away from the printing position, to a position wherein the links are again at an angle to each other. to allow the resilient means to return the platen tolthe printing position. v

8. In a typewriter of the character described, a plurality of type bars, means for advancing the type bars to a printing position, a platen shiftable towards and away from the type of the type bars'when the latter are in printing position, resilient means urging said platen toward the printing position, a universal bar actuated by the type bars, a toggle linkage comprising a pair of connected links, the first of which has its 'free end connected to the platen and the second of which has its free end mounted on a stationary pivot, a rocker arm carried by'said second link and shlftable in a plane perpendicular to the center line of the second link, lugs carried by the ends of said rocker arm, and means actuated by said universal bar for engaging one of said lugs to shift the linkage through its dead center to move the platen away from the printing position and when the latter are in printing position, resilient means urging said platen toward the printing position, a universal bar actuated by the type bars, a toggle linkage comprising a pair of connected links, the first of which has its free end connected to the platen and the second of which has its free end mounted on a stationary pivot, a rocker arm carried by said second link and shiftable in a plane perpendicular to the center line of the second link, lugs carried by the ends of said rocker arm, a member provided with a pair of lugs to engage the lugs on said rocker arm, means'actuated by said universal bar for moving said member toward said rocker arm to shift the toggle linkage through its dead center and move the platen away from the printing position and allow it to return under the action of the resilient means, and means associated with said toggle linkage and operable upon passage of said linkage through its dead center for shifting said rocker arm to place the lug at one end in the path 01 travel of a lug on the member and to place the lug on the other end out of the path of travel of a lug on said member.

CAMILLO OLIVETTI.

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