US2045997A - Typewriting machine - Google Patents

Description

June 30, 1936. R v. REPPERT TYPEWRITING MACHINE Original Filed Dec. 18, 1933 m w l 0 n. 4 m w IX. 0 N L.. 2 4k 3 N mm x 2 Q |||l-HMHN MHHHMH UHMHHI m R 2 .2 mm v Q 9 2 k IN V EN TOR.

BY' Z Q ATTORNEY Patented June 30, 1936 PATENT OFFICE 2,045.99: TYPEWBITING MACHINE Richard V. Reppert, Binghamton, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Original application December 18, 1933, Serial No. 702,856. Divided and this application September 26, 1934, Serial No. 745,542

4 Claims.

The present invention relates to power operated typewriting machines and is a division of my copending application Serial No. 702,856 filed December 18, 1933.

The broad object of the invention is to provide a simple and effective device for controlling the impact force of the type bars or other printing instrumentalities whereby a typewriting machine may be readily adjusted to the quality or thickness of the paper or the number of typewritten copies desired.

Another object is to provide an impact controlling device which is easily incorporated in machines now in use.

Various other objects, advantages, and features of the invention will be pointed out in the following description and claims or will be apparent from a studyof the drawing which represents a vertical section of a power operated typewriter.

While this invention has been illustrated in the drawing in connection with the power type bar action disclosed in my copending application above mentioned, the present invention is capable of bing used in other typewriting machines now on the market or already in use. As the specific construction of the power type bar action is not of particular importance, so far as an understanding of the present invention is concerned, only a brief general description of its operation will be ven herein.-

, In manually operated typewriting machines, the force of impact is easily regulated by the operator who learns by experience the proper amount of pressure or speed of the fingers in striking on the keys. When single sheets are being typed, alight pressure or blow is preferable and sufilcient to produce clear imprints without cutting the paper. When a number of carbon copies are desired, the operator increases the force applied to the keys in proportion to the number of copies required.

The situation is diflerent in modern high speed power operated typewriting machines as the keys a merely operate or release mechanisms which subsequently connect the type bars or other printing instrumentalities to a power driver or universal actuator of some sort. The pressure required to operate the keys and the amount that they may be depressed is constant regardless of the nature of the work to be done and it is immaterial how hard or how fast the keys are struck.

The practice in the art varies in respect to Y how the force or the blow is regulated. In some machines the force of the blow may be varied by changing the duration of time the type bars are connected to the power operator so that they may remain under control of the power operator for a longer period when one or more carbon copies are desired than when Writing on a single sheet. As the number of carbon copies desired is increased, the machine may be adjusted so that the type bars are connected to the power operator for progressively longer periods. In other machines the same results are obtained by increasing the speed of the power operator in accordance with the number of copies desired, as by cutting out resistance in series with the driving motor. Both of these methods are used in commercial machines.

The first method is objectionable as it requires a very careful adjustment of the machine and the parts necessary for its accomplishment are subject to wear and also because the degree of adjustment is extremely limited by such practical considerations as the size and proportions of the parts of the power system.

The second method is objectionable as, while it is the simplest of all, it requires that the machine be increased in speed beyond normal requirements in producing carbon copies thereby introducing wear problems and narrowing the time allowed for proper response of the parts to the limit of safety for reliable operation.

The present invention aims to provide a method which is intermediate the two methods in the senses of requiring fewer parts than the first method and having the simplicity of the second method, while retaining the beneficial features of both. The problem of wear on the power driver and connected parts will be eliminated so far as any efiect upon the regulating of the force of the blow is concerned, the amount of wear being no greater than would be the case if no impact controlling mechanism were provided.

A convenient method of regulating the force of the blow without providing many additional parts subject to wear or derangement consists in taking advantage of the energy absorbing properties of the usual spring actuated universal bar directly actuated by the type bars and commonly used in commercial machines like the Underwood, for example.

In the drawing there is shown a pivoted type bar I mounted and operated by a sub-lever 2 in a manner now commonly employed in many commercial machines such as the Underwood. The specific means for operating type bar l is immaterial but for convenience it has been shown in connection with a power type bar action like that disclosed in copending application Serial No. 702,856. In this mechanism, the depression of a key 4 causes a detent 5 carried by the key lever to move to the left, thereby permitting a spring 6 to rock an element 1 counterclockwise.

A toothed'disk or star wheel 8 rotatably mounted on element 6 is thus caused to positively engage the teeth of a constantly rotating power actuator 9 which may be driven by a motor in the usual way.

The disk 8 is rotated by the actuator 9 andits initial rotation causes element 6 to be relatched by detent 5 while its subsequent rotation causes sub-lever 2 to be rocked clockwise by a cam finger l0 secured to said lever and in the path of the teeth in disk 8. Clockwise movement of the sub- I lever 2 causes the type bar to move in an are the right hand side plate of the machine.

until it strikes the platen A spring l2 connected to sub-lever 2 restores the type bar and sub-lever after each operation. The proportions of the parts and their relative positions are such that at a reasonably low speed of the power operator 9 there will be sufficient impact force of the type bars to take care of the heaviest work which the machine may be required to perform. Preferably the parts of the power drive mechanism, notably cam finger l0 and disk 8 are so related that no driving force is imparted to the type bar by actuator 9 beyond the point where the type bar operatively engages the universal bar hereinafter. ,to be described. This condition is not essential but is prefered as with it the load on the power actuator will be nearly always constant, at least as far as the operation of the type bars is concerned, regardless of the adjustment of the impact controlling device. In some cases, particularly machines designed for extra heavy duty as where a very large number of carbon copies is desired, it may be necessary to keep the type bar under the influence of the power actuator for a longer period in order that the maximum force of impact may be as great as possible.

Each type bar [has a shoulder or heel l3 which is adapted, when the type bar is near the platen l I, to strike a universal bar M. The latter is of a form commonly used in the art, it being found in Underwood machines, for instance, and ordinarily controls the carriage escapement or letter spacing mechanism. When struck by the heel I 3 of a type bar, the universal bar moves a small amount rearwardly of the machine (to the left in the drawing) against the tension of a spring l5. Normally the spring l5 exerts only slightly more tension on the universal bar HI than is necessary to assure restoration of the universal bar when the type bar is restored by spring II2 to provide a fair margin of safety. It is evident that the resistance offered by universal bar II to the movement of the type bars will normally be fairly V constant in value with a given size of spring and a fixed point of connection of the spring to the frame (if the machine Means is provided, according to the present invention, for varying the tension of the spring I5 in order that the amount of energy absorbed by the spring may be varied thereby controlling the force of impact of the type bar. Spring IS instead of being fixedly mounted in the usual way, is anchored to the free end of an arm l6 secured to a shaft ll. The latter is journaled in the framework of the machine and extends toward Adjacent the right hand side frame there-is secured to shaft II a worm sector I? with which cooperates a worm l9 secured to a shaft 20 journaled in the framework. The shaft 20 extends through the front plate of the machine conveniently near the keyboard and secured to this shaft is a knob or finger piece 2| having a suitable index or pointer 22. The latter cooperates with'a suitable scale on a plate 23 secured to the front plate or the scale may be placed directly on the front plate.

By rotating knob 2| by hand, the operator of the machine can increase or decrease the tension of spring l5 thereby decreasing or increasing the force of impact of the type bars.

Obviously, as the tension of spring ISincreases the resistance offered by the universal bar ll to the movement of the type bars as they approach the platen will increase and the force of impact will be decreased thus weakening the impressions produced by the type bars. When the universal bar is used to operate the escapement mechanism and/or the ribbon vibrator as is usually the case, the spring l5 must always have a certain amount of tension and in such cases it will be desirable to provide suitable limit stops to prevent the knob 2| from being set to place spring I5 under less tension than necessary for proper operation of the escapement mechanism and/or ribbon vibrator and to prevent placing spring I5 under too great a tension. In machines having a separate universal bar for operating the ribbon vibrator These stops have not been shown as they are purely a matter of judgment and skill in construction.

One of the important features of the construction shown in-the drawing is its simplicity which requires very few parts. Another feature of importance is the fact that the invention may be readily applied to existing power driven typewriting machines not equipped with impact controlling means as by very slight changes in the design of the parts the mechanism herein described can be easily manufactured as an attachment since most power driven typewriters have a universal bar like for operating either the escapement mechanism or ribbon vibrator or both.

Other very important features of the construction are the facts that it need not impose any additional load on the power drive mecha;- nism or interfere with the proper operation of the power drive mechanism or cause wear therein.

The present invention has been illustrated and described as embodied in a specific form in connection with a specific type of power type bar action; however it is limited neither to the form nor type of power type bar action shown as the invention may take other forms. or be modified in detail, or be used in connection with other forms of power type bar action. Accordingly it is desired that the following claims be limited in scope only by the prior art.

What is claimed is:

1. In combination, a type bar, power means for operating the type bar, a universal bar actuated by the movement of the typebar, a spring acting on said universal bar in a direction to cause the universal bar to retard movement of the type bar and reduce its velocity, and a manually adjustable tension regulating device connected to the spring and operable at will to regulate the tension of the spring whereby to control the velocity of the type bar, said device comprising a pivoted arm to which the spring is connected, a shaft having a finger piece for turning the shaft and a pointer cooperating with a fixed scale, and a worm and sector connection between the arm and shaft.

2. In combination, a platen adapted to support a record sheet, a printing member movable toward the platen to efiect an impression, power means for moving said member, means for retarding the movement of the member toward the platen including a spring, and a manually adjustable tension regulating device connected to, the spring and operable at will to regulate the tension of the spring whereby to regulate the impact pressure of the printing member on the record sheet, said device comprising a rotatable arm to which the spring is connected, a rotatable finger piece, and a worm and sector driving connection between said finger piece and arm.

3. In combination, a platen adapted to support a record sheet, a printing member movable toward the platen to effect an impression, power means for moving said member, means for retarding the movement of the member toward the platen including a spring, and a manually adjustable tension regulating device connected to the spring and operable at will to regulate the tension of the spring whereby to regulate the impact pressure of the printing member on 5 the record sheet, said device comprising a rotatable finger piece, and worm and sector means connecting said finger piece and spring whereby rotation of the finger piece changes the tension of the spring.

4. In combination, a platen adapted to support a record sheet, a printing membermovable toward the platen to effect an impression, power means for moving said member, means for retarding the movement of the member toward the platen including a spring, and a manually adjustable tension regulating device connected to the spring and operable at will to regulate the tension of the spring whereby to regulate the impact pressure of the printing member on the record sheet, said device comprising a rotatable finger piece, a worm actuated by said finger piece, and a member having a toothed relation to the worm and connected to said spring whereby rotation of the worm by said finger piece varies the tension of said spring.

RICHARD V. REPPERT.

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