US2119928A - Noise-damping device for powerdriven typewriters - Google Patents

Description

June 7, 1938.

A. SAL'Z'BERGER NOISE DAMPING DEVICE FOR POWER DRIVEN TYPEWRITERS Filed Feb. 17, 1957 HHHHIIIH.

Inventor- A-nczrezs s aZzZQrgB/ IHHHHII.

Afforneys Patented June 7, 193 8 NOISE-DAMPING DEVICE FOR- POWER- I DRIVEN TYPEWBIITEBS Andreas Salzberger, Eriurt, Germany, assignor to Olympia Biiromaschinen-werke A. G Erfnrt, Gel-mam Application February '17, 1931, Serial No. 126,283 In Germany February 21, 1936 7 Claims.

This invention relates to power-driven typewriting machines withnoise-dampenedimpression of the kind described in my U. S. Letters Patent No. 2,059,537, in whichthe type-levers are positive- 1y actuated by the intermediary of an eccentric and in which the thus actuated typelever when having arrived in the proximity ofitsupperdeadcentre position is engaged by a rotary pressingon member which transmits additional power to it and presses it with correspondingly increased ,force against the platen or paper roller.

In order to attain with type-writing machines of the above kind an increased writing speed, it is indispensably requisite that the co-operation of the type-lever lifting device with the pressingon device be unobjectionable and take place without the generation of noise. In other words, the

type-lever and all members oscillating together,

with it must be accelerated positively and gradually, without being thrown or flung at the commencement of its lifting movement, and this movement must be gradually retarded towards the end, so that no blow proper is produced when the type contacts with the paper-on the platen and the additional pressing-on of the type upon the paper takes place in the proper moment.

In the above mentioned patent type-levers and intermediate levers of usual design are used,

these members being coupled with one another,

by means of joints comprising pins and slots in which thepins are guided, the entire system being actuated by a lever provided with a roller held against an eccentric by means of a spring.

I Springs are, however, no reliable members in 3 a type-writing'machine and-are only adapted to prevent flinging under certain conditions. Be-

sides, at the return motion of the rods and links these members are not in all cases taken along with the driving members concerned, and the 40 joint pins guided in slots, as already mentioned,

are subject to undesired additional accelerations which partly cause disturbances and, apart from diflicult adapting work, give rise to rattling noises especially at a higher writing speed.

45 Now, the-above mentioned drawbacks and disadvantages of the known mechanism dealt with in the preceding paragraphs are obviated in and by my present invention, the chief characteristic feature of which is that the race path of the cc- 5,, centric co-operates with an oscillatable member provided at its opposite ends with small blocks or, maybe, small rolls bearing on said race path, said oscillatable member being in driving connection with an intermediate lever connected with the i type-lever by toothed segments, of which one is provided at the type-lever, and the other at the 1 free end of said intermediate lever.

This arrangement does not onlypresent the advantage that the driving power is not loaded at all with the springs hitherto necessary for the 5 return movement of the levers, but it is, besides, now rendered possible to make use of only one size of the mentioned intermediate levers, as all their supporting points can lie concentrically with re: spect to the circularly arranged supporting points of the type-levers. It is to be understood that toothed type-levers and toothed intermediate levers are known per se.

Concerning the noise-dampening another improvement resides therein that another member is likewise able to contact elastically with the race path of the eccentric is co-ordinated to one of the first-mentioned blocks or rolls, the object of said other member being to compensate small diflerences of distance and it is preferably hinged to so the circularly curved oscillatable member and is. arranged ahead of the block or roll at the adjacent end of this member in such a manner that it imparts to the eccentric an additional rotary movement when the eccentric is in an approxig5 mate dead-centre position.

The invention is illustrated diagrammatically and by way of example on the accompanying drawing of which Fig. 1 is a side view oi the en.- tire mechanism concerned, and Fig. 2 is a side view showing a modification. V

On the drawing, i denotes the type-lever which is provided at its rear end with a circularly curved toothed sector la, the teeth 0! which lie concentrically with respect to the fulcrum 2 of said lever. Said sector la meshes with another toothed circular sector 30. provided at the free end of an intermediate lever 3' and lying concentrically with respect to the fulcrum 3b of this lever.

4 denotes the eccentric disc to which is turnably attached at one of its sides the known catch-pawl 5 which is moved into operative position by means, of a pawl I attached to the free end of the keylever 6, and by two double-armed intermediate levers 8 and 9. These members (1, 8, 9) and their manner of operationare known, for which reason I abstain from entering into details concerning them. In the drawing the parts hitherto mentioned are shown in their position of rest.

As regards now the transmission of motion from the eccentric 4 to the type-lever l, (at the type end of which is visible a particularly shaped curved, downwardly directed projection lb intended ior co-oneration with a specially provided 56 stance a small roll I! which bears on the circumferential race path of said eccentric. Illa denotes the upper leg of this lever, Hlb the lower one. The leg Illa of the lever I0 is jointed at I to one end oi a link l3, the-other end of which is hinged to the toothed segment 3a of the intermediate lever 3, whereby the lever I0 is connected also with the key-lever l by the intermediaryof the two toothed sectors, as appears clearly from the drawing.

The outer circumference of the eccentric disc I is not accurately circular, but its shape is, anyhow, such that the width between the rolls I2 is always the same. 3

As has already been mentioned, small pivoted blocks l 9, Fig. 2, may be used instead of the small rolls l2, but irrespective of whether rolls or blocks are employed, there arises, especially if the writing speed is comparatively high, a rattling noise owing to the continual change of direction as soon asthe distance between the rolls or blocks and the eccentric varies even only very slightly. I obviate said noise in my present improved mechanism by the following contrivance:

The pivot H which connects the link I3 with the leg Illa of .the double-armed lever Ill supports also a double-armed lever l5 which carries at one arm a race-roll I l 8 bearing likewise on the circumferential race path of the eccentric 4, and being at its other end connected with one end of a helical tensile spring H, the other end of which is attached to an arm I00 forming part of the lever l0 so that the roll I6 is pressedagainst the eccentric. Thereby the lower roll I! is .also pressed against the eccentric and,-owing to the co-operation of the two upper rolls, the lever I0 is completely prevented from making jerky movements if there eventually should arise a small diflerence between the diameter of the eccentric and the-distance between the rolls II.

An important feature resides, finally, in that the additional roll I6 is not arranged at a side of the adjacent roll l2, but ahead of the same as regards the direction of rotation of the eccentric, in consequence whereof the roll l6 tends to turn the eccentric in clockwise direction about its axis l8 when the eccentric is in its lower dead-point position, as in the drawing. Owing to this action, the eccentric is secured in place when it is in its position of rest, that is to say, the interengaging hooks of the pawls 5 and 8 are firmly pressed against one another, but instantly after the pawl 9 has been released by a depression of the keylever B the rotary motion of the eccentric is' initiated.

The mechanism canbe designed to operate particularly noiselessly by substituting turnable or oscillatable blocks IQ for the rolls H, as has already been mentioned, but in such a case it is requisite to lubricate the circumferential race of the eccentric.

It must be mentioned that the eccentricdisc 4 and the double lever (III) are provided with grooves or holes or the like on as many places as possible to,avoid unnecessary swing-masses.

I claim:-- 1. A mechanism for obtaining noise-dampened imprints of the type-levers of a power-driven type-writing machine, comprising in combination .with the type-levers a power-driven rotating desaid oscillating member is pivotally arranged and pivoted blocks are provided at the ends of said member engaging said eccentric disc.

3. A mechanism as specified in claim 1 in which a second member is provided pivotally arranged on said first member, the one end of which yieldingly engages the eccentric disc:

' 4. A mechanism for obtaining noise-dampened imprints of the type-levers of a power-driven type-writing machine comprising, in combination with the type-levers, a power-driven rotating device adapted to lift the selected type-lever and comprising a shaft, an .eccentric disc and. means adapted to couple saidshaft with said disc, an

oscillating-member engaging said eccentric disc.

on opposite points, an intermediate lever pivotmediate lever with said type-lever to eifect-a contemporaneous swinging movement and a second oscillating member pivoted on said first mentioned one and yieldingly engaging said eccentric disc.

5. A mechanism as specified in claim4 in which the point of engagement of the said second member with the eccentric disc is arranged ahead of the adjacent point of contact of the said first oscillating member.

6. A mechanism as specified in claim 4 in which rolls are provided on the ends of said members engaging the eccentric disc.

7. A mechanism as specified in claim 4 in which the point of engagement of the said second member with the eccentric disc is arranged ahead of the adjacent point of contact of the said first oscillating member in such a manner that said second member tends to turn the eccentric disc when the latter is near to its dead-point position.

ANDREAS SALZBERGER.

, ally arranged and connected with said oscillating member. means adapted to couple said inter--

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