US3774745A - Apparatus for adjusting the impact force of types - Google Patents

Abstract

A control bar extending across the type actions of an electric typewriter, has a lowercase abutment and an uppercase abutment which are placed in an operative position, respectively, by the case shift key for differently limiting the free inertia movement of a driven lever, and thereby the impact force of the type faces, either by setting a stop spring engaged by the driven lever at the end of its inertia movement, or by effecting separation of the coupling means of the driven lever from the power roll for determining the moment in which the inertia movement of the driven lever with the type bar starts.

Description

United States Patent 1 Fuchs [111 3,774,745 1 Nov. 27, 1973 APPARATUS FOR ADJUSTING THE IMPACT FORCE OF TYPES [75] Inventor: Hans Fuchs, Wilhelmshaven,

Germany [73] Assignee: Olympia Werke AG, Wilhelmhaven,

' Germany [22] Filed: June 3, 1971 21 Appl. No.: 149,438

[30] Foreign Application Priority Data June 13, 1970 Germany P 20 29 332.7

52 US. (:1. 197/17 [51] Int. Cl B4lj 23/08 [58] Field of Search 197/17, 16, 98

[56] References Cited UNITED STATES PATENTS 2,796,966 6/1957 Toeppen.... 197/17 3,393,786 7/1968 Heidt 197/17 3,259,223 7/1966 Heidt et al. 197/17 3,393,788 7/1968 Dodge 197/17 3,250,366 5/1966 Rix et a1. 197/17 3,458,024 7/1969 Schaefer 197/ 17 3 ,204,746 9/1965 Wolowitz 197/17 X 2,750,022 6/1956 Long 197/17 FOREIGN PATENTS OR APPLICATIONS 1,190,008 5/1963 Germany 197/17 UX 1,192,662 7/1963 Germany 196/17 UX Primary Examiner-Robert E. Pulfrey Assistant ExaminerR. T. Rader Attorney-Michael S. Striker [57] ABSTRACT A control bar extending across the type actions of an electric typewriter, has a lowercase abutment and an uppercase abutment which are placed in an operative position, respectively, by the case shift key for differently limiting the free inertia movement of a driven lever, and thereby the impact force of the type faces, either by setting a stop spring engaged by the driven lever at the end of its inertia movement, or by effecting separation of the coupling means of the driven lever from the power roll for determining the moment in which the inertia movement of the driven lever with the type bar starts.

7 Claims, 5 Drawing Figures PAIENTEDNUVIE'? 19/5 3.774.745

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IN VE N TOR" nus Fuel/5 APPARATUS FOR ADJUSTING THE IMPACT FORCE OF TYPES BACKGROUND OF THE INVENTION The present invention relates to apparatus for adjust ing and setting the impact force of the type bars of electric typewriters and other business machines. In order to obtain a uniform appearance and density of all characters typed on a typewriter, the impact force exerted by each type face on the platen, must be proportional to the area of the respective character. For example, a capital M requires a greater impact force than a period.

Apparatus is known for adjusting the impact force of uppercase type faces and lowercase type faces differently, and for adjusting the impact force of each type action individually.

The apparatus according to the prior art provides a bar turnable between two positions corresponding to the uppercase and lowercase type faces, and having two rows of adjustable stop screws individually determining the impact forces of the uppercase character type faces and the lowercase character type faces.

The apparatus of the prior art has the disadvantage that the adjustment of the impact forces of the type faces can only take place after the shiftable bar has been assembled together with the adjustable stop screws, whereupon each adjustable stop screw is individually adjusted for uppercase characters and lowercase characters. Since the individual adjustment can be carried out only from the bottom of the typewriter, it is necessary to lift and again put down the typewriter to adjust each screw and then trying out the results of the adjustment by operating the respective type action. As a result, the adjustment of the impact forces of all type faces is a very time consuming operation.

It is one object of the invention to provide an apparatus for adjusting the impact forces on type faces, which permits a quick individual'adjustment of the impact force of each type in the lowercase position as well as in the uppercase position.

Another object of the invention is to provide an apparatus for adjusting the impact forces of types having uppercase and lowercase type faces collectively and individually.

Another object of the invention is to provide an apparatus for adjusting the impact force of types which permits adjustment and testing without lifting of the typewriter.

With these objects in view, the present invention provides control means including a lowercase abutment and an uppercase abutment of different heights which correspond to the different impact forces of uppercase type faces and lowercase type faces, and furthermore adjusting means for individually adjusting each type action.

This arrangement permits a simple and quick adjustment of the impact force of each type face, since after the assembly of the control means with the two abutments which are common to several type actions, only each type action has to be individually adjusted. The different friction conditions in the several type actions are equalized by providing an adjusting member for each type action. In one embodiment, groups of individual abutments are arranged in two rows in the longi tudinal direction of a control bar which is shifted in the usual manner by the case shift means under the control of the shift key. Preferably, the control bar consists of a lightweight synthetic material, so that the control bar with the abutments can be replaced by other control b'ars, according to the fonts of type faces used. For the adjustment of the type actions, a simple construction according to the present invention comprises resilient adjustable stop means which are engaged by the drive lever of the respective type action and resiliently displaced for a distance limited by one of the abutments of the control bar. The resilient stop means serve the purpose to dampen the energy of the type action according to the area of the type face which is to produce the printing impact, and on the other hand to dampen the rebound of the type actions or parts of the same to such an extent that no inertia movement beyond the correct position can take place during the return movement of the type action whereby an undesired double actuation of the typewriter is prevented. An effective damping is. obtained in accordance with the invention, by providing resilient stop means which consist of superimposed leaf springs.

In a preferred embodiment of the invention, a typewriter is used which has a power roll by which all type actions are actuated with a constant force, and in which a resilient means is provided as a brake for regulating the constant force in accordance with the size of the respective type face.

The apparatus of the invention is advantageously used with an electric typewriter which includes a power roll; a row of type actions, each of which includes a type bar having a lower case type face and an upper case type face, a driven lever, coupling means movably mounted on the driven lever and cooperating with the power roll so that the driven lever is accelerated until the coupling means separates from the power roll and the driven lever freely moves in an inertia movement along a pathremoving the type bar toward a printing position; and case shift means having a lowercase position and an uppercase position for rendering the lowercase type face and the uppercase type face operative, respectively, and which include a shift key for shifting the type bar segment and the carriage with the platen relative to each other.

The apparatus of the inventioncomprises an adjustable, preferably resilient, stop means correlated with each type action and located in the path of the respective driven lever for terminating its free inertia movement; and control means including a lowercase abutment and an uppercase abutment of different heights, said control means being operated by the case shift means to place the respective abutment in an operative position.

The abutment in the operative position cooperates with a part of the type action, either with the coupling means or with the driven lever, to determine the length of the inertia movement of the driven lever so that the driven lever moves different'distances in the inertia movement, and the lower and upper type faces exert different impact forces when the lowercase abutment or theuppercase abutment is in the operative position.

Th novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. The invention itself, however, both as,

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary perspective view illustrating a type action adjusted in accordance with one embodiment of the invention;

FIG. 2 is a fragmentary side view of parts of the embodiment of FIG. 1;

FIG. 3 is a fragmentary sectional view illustrating a modified control means which could be used in the embodiment of FIGS. 1 and 2;

FIG. 4 is a fragmentary side view illustrating another embodiment of the invention; and

FIG. 5 is a fragmentary side view illustrating a third embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. I and 2, only a single type action of a row of type actions is illustrated, and includes a driven lever 9 mounted for rotation on a shaft 11 and being connected by a wire connector 13 with a type bar 15 which carries a type 15c with a lowercase type face and an uppercase type face 151;. FIG. 1 further snows a shaft 17 on which a key lever 18 carrying a key I9 is mounted for angular movement, only one key 19 and key lever 18 being shown to cooperate with the illustrated type action.

Key lever 18 has a projecting portion 21, and is biassed by a spring 22 to a normal position. A control lever 23 is mounted for angular movement on a shaft 25 and abuts a tensioned leaf spring 31. Control lever 23 has a cam follower arm 27 and is urged by leaf spring 31 against the cam portion 39 of a coupling means 33 which is rotatably mounted on driven lever 9, and cooperates with a rotary power roll 37. When a key 19 is operated, control lever 23 is displaced in counterclockwise direction by projection 21 so that arm 27 turns coupling means 33 to a position engaging the power roll 37 so that coupling means 33 is rotated, and driven lever 9 is angularly displaced to operate type bar 15 until the coupling means 33 separates from the power roll whereupon driven lever 9, connecting wire 13, and type bar 15 move freely in an inertia movement type bar 15 moving toward the platen, not shown.

The construction and actuation of the type action is not an object of the present invention, and explained and descfibed in detail in the copending application Rix ct Ser. No. 62,781, entitled Type Action Drive.

The driven lever 9 of each type action, has an arm with an end portion 41 cooperating with a spring finger 3. Spring fingers 3 are the prongs of a comb structure which consists of three superimposed spring combs 45, 47, 49 which are secured in a frame portion 43. Accordingly, each spring finger 3 consists of superimposed leaf springs 3a, 3b, 3c.

Adjusting screws 2 are mounted on the frame portion 43, and it is apparent from FIG. 2, that each spring finger 3 can be bent and adjusted by adjustment of respective screw 2. The end portion 41 of driven lever 9 cooperates with the end of the respective spring finger 3 which is located in the path of move :rnt of end portion 41 of driven lever 9 when the i e bar 15 approaches the printing area upon an ac. 1 on of the respective type action. Each spring finger '5 1d adjusting screw 2 constitutes an adjustable res stop means for the driven lever 9 of the respective type action, permitting individual adjustment of each type action.

Since the adjusting screws 2 are arranged in a row under the keyboard formed by type levers 18 and types 19, as best seen in FIG. 1, adjusting screws 2 are accessible from the front of the typewriter, and can be individually adjusted while the typewriter is in a normal position in which it is possible to operate the respective key 19 directly after adjustment in order to check whether the imprint made by the respective type face 15a or 15b is satisfactory. Repeat actuation mechanism, not shown, may be used for obtaining successive impacts of the respective type face 15a or 15b, while the respective screw 2 is being adjusted, so that the moment in which the correct impact force is obtained is clearly apparent from the successive imprints.

Due to the fact that the individual resilient stop means 3 of each type action consists of superimposed leaf springs 3a, 3b and 30, on the one hand a high damping and absorption of the rebound energy of the type action is obtained, so that an undesired double action of a type action is desirably avoided. On the other hand, the leaf springs 3a, 3b, 3c require little force for adjustment of the respective adjusting screw 2.

The spring fingers 3 abut in a normal position of the apparatus, on an eccentric stop bar 51 which extends across all spring fingers 3 which is mounted on a shaft 53. for turning movement, as best seen in FIG. 2. Depending on the angular position of the eccentric stop bar 51, each spring finger 3 can be bent downward by the respective adjusting screw 2 until abutting stop bar 53. A lever 55 is connected with the eccentric stop bar 51 for angular movement, and lever 55 is provided with arresting recesses 61 engaged by an arresting pawl 63 mounted on the frame of the apparatus, not shown. A link connects lever 55 with a manual lever 59 which can be turned about a pivot 65 between a number of positions in which lever 55 and eccentric stop bar 53 are angularly displaced so that the point at which each spring finger 3 abuts the stop bar 51 is displaced along the length of the respective spring finger 3.

Eccentric stop bar 51 serves for simultaneously varying the impact force of all type actions associated with the spring fingers 3, respectively, as may be required for producing different numbers of copies. This adjustment can be carried out after each spring finger 3 has been adjusted by the respective adjusting screw 2 in accordance with the area of the type faces associated with a second type action.

In the position of manual lever 59 illustrated in FIG. 2, when the eccentric stop bar 51 is placed in the position shown in solid lines, the resilient spring fingers 3 permit the greatest impact force, while in the position of the stop bar 51 and lever 55 shown in broken lines, the smallest impact force is produced by the type actions.

The spring fingers 3 abut the eccentric stop bar 51 with a pretension, which can be varied by adjusting screws 2 in accordance with the area of the type faces of the respective type action. Due to the adjusting screws 2 and to the eccentric stop bar 51, the ends 67 of the spring fingers 3 can be adjusted to higher and lower positions so that the end portions 41 of the driven levers 9 engage the ends 67 of spring fingers 3 sooner or later when driven lever 9 moves in a free inertia movement after separation of the coupling means 33 from the power roll 37. Since type bar IS with type 15c moves with driven lever 9 in the inertia movement, the impact force is adjusted.

Under the free ends 67 of the spring fingers 3, a control bar 1 having two longitudinally extending angularly spaced abutments la and 1b is mounted for angular movement on a shaft 69. Control bar 1 is connected for angular movement with a lever arm 4 which is pivotally connected with a link 6 which is part of a case shift means, not shown, which include a case shift key, not shown, for setting the typewriter to type lowercase characters by the use of type faces 15a or uppercase characters by the use of type faces 15b. The case shift means, of which link 6 is a part, are entirely conventional and not an object of the invention, and consequently not illustrated in detail. I

It will be understood that by operation of the shift key, not shown, control bar 1 will be turned so that instead of the lowercase abutment, the uppercase abutment will engage the ends 67 of the spring fingers 3.

The abutments 1a and 1b of control bar 1 preferably consist of longitudinal row of abutments, each engaging one of the spring fingers. In the modified embodiment shown in FIG. 3, each of the two abutments of a control bar 10, consists of a row of adjustable screws 10a and 10b which permits further individual adjustment of the spring fingers 3 separately for the lowercase type faces and the uppercase type faces. The adjustment of the abutment screws 10a, 19b may be carried out by an automatic apparatus in accordance with the used font of the type faces a, 15b. The individual adjustments of the entire type action, is obtained by adjustment of the respective adjusting screws 2.

When a key 19 and key lever 18 is operated, the respective control lever 23 is turned in counterclockwise direction while the energy stored in the respective springs 31 isreleased'so that the coupling'means 33 with the coupling cam 35 is placed in a position in which coupling means 33 is engaged and rotated by power roll 37. Due to the eccentric position of cam 33 on the'driven lever 9, the same is driven in clockwise direction. When coupling means 33 separates from power roll 37, parts 9, 13 and 15 of the type action start a free inertia movement whose kinetic energy is limited due to the cooperation between the end portion 41 of driven lever 9 with the pretensioned spring finger 3, and furthermore due to the fact that the displacement of each spring finger 3 is limited in two different end positions, depending on which of the abutments 1a, 1b of control bar 1 is operative and cooperates with the respective spring finger 3. Depending on the position of the shift key, the links 6 and 4, and the type segment 14, the lowercase type face 150 or the uppercase type face 15b is effective.

In the above described embodiment of FIGS; 1 and 2, the adjustment of each type action is carried out by stopping the end portion 41 of driven lever 9 at different adjusted points. However, it is also possible to adjust the moment in which the free inertia-movement of driven lever 9 with type bar 15 begins so that the amount of energy driving the type action in the free inertia movement is varied, together with the length of the distance which the driven lever 9 moves in the free inertia movement.

The embodiments of FIGS. 4 and 5 have the same type action, which is different from the type action of the embodiment of FIGS. 1 and 2. A support 85 has a journal 89 on which a driven lever 77 is mounted for angular movement. Lever 77 is connected by wire 91 with a type bar 93 which is constructed as described for type bar 15 shown in FIG. 1. As shown in FIG. 5, a key lever 97 provided with a key 99, is mounted on a shaft 95 which is supported in the frame of the machine, not shown. Each key lever 97 has an actuating arm 101 which cooperates with an abutment 103 on a coupling lever 71 which is mounted on driven lever 77 for angular and straight movement, and is biased by a spring 105 which connects driven lever 77 with coupling lever 71.

Coupling lever 71 has a cam portion 107 which cooperates with the power roll 75. Coupling lever 71 has an arm 105 whose end portion 111 cooperates with a stationary cam 113 which is a part of support 85.

In order to adjust the impact and printing force, a

. control edge 115 of arm 109 cooperates with an adjusting screw 73 mounted on a fixed bar 117. The position of coupling lever 71 in which the edge 1 15 abuts the respective screw 73, is shown in broken lines. A screw 73 is provided for each type action and cooperates with the respective coupling lever 71 to limit its movement.

The driven lever 77 has an end portion 119, corresponding to the end portion 41 in the embodiment of FIGS. 1 and 2, which cooperates with the respective spring finger 121, which corresponds to spring finger 3 in the embodiment of FIGS. 1 and 2. An eccentric stop bar 125, and a control bar 123 with a lowercase abutment and an uppercase abutment 123a and l23b are provided, and are angularly displaced as explained in detail with reference to FIGS. 1 and 2 for. eccentric stop bar 53 and control bar 1.

The embodiment of FIG. 4 operates as follows: When a key lever 97 is shortly depressed by pressure on key 99, see FIG. 5, the actuating arm 101 displaces coupling lever 71 due to engagement with abutment 103 so that the cam portion;107 is engaged by power roll 75, and the arm 109 with end portion 111 is lifted off the control cam 113 on support 85. The power roll turns coupling lever 71', and accelerates driven lever 77 and type bar 93 until the control edge 115 of arm 109 of coupling lever 71 engages the adjusted screw 73. When coupling lever 71 is stopped in this manner .it separates from power roll 75, and no force is transmitted from the power roll 75 to the cam portion 107. Consequently, the moment of separation of coupling lever 71 from power roll 75, and the start of the free inertia movement of the type action, depends on the adjusted position of the respective adjusting screw 73. By adjustment of the several screws 73 respectively correlated with the several type actions, the parts 77, 91, 93 of each type action can be supplied with the same amount of' energy, and receives the driving impulses.

At the moment in which the engagement between cam portion 107 of coupling lever 71 and the power roll 75 is interrupted, driven lever 77 starts a free inertia movement together with wire link 91 and type bar 93. In order to brake the type actions individually in accordance with the size of the type faces thereof, irrespectiveof the fact that all type actions are driven by the same amount of energy as determined by adjustment of screws 73, the end portion 119 of each driven lever 77 cooperates with the respective spring finger 83 whose resilient displacement is controlled by the control bar 123 in accordance with the position of the case shift means, and by the stop bar 125 in accordance with the number of copies which have to be made.

FIG. illustrates a third embodiment of the invention, whose type action has been described above. In the embodiment of FlG. 5, the control bar 79 with a lowercase abutment 79a and an uppercase abutment 79b is mounted for cooperation with the control edge 115 of arm 109 of coupling lever 71. When control edge 115 engages abutment 79a in the broken line position of coupling lever 71, cam portion 107 of coupling lever 71 separates from power roll 75, and the free inertia movement of driven lever 77 is started. When control bar 79 is shifted by thecase shift means, not shown, to the other angular position in which abutment 79b cooperates with control edge 115, the separation of the coupling lever. 71 from the power roll 75 takes place at another moment so that a different amount of energy is transmitted to the type action, and the free inertia movement of driven lever 77 is started at another moment and has a different length than when abutment 79a was in the operative position.

The individual adjustment for each type face is effected by adjusting screws 83 cooperating with spring fingers 81 as described in detail with reference to FIGS. 1 and 2. An eccentric stop bar 125 also cooperates with the spring fingers 81 for simultaneously adjusting all type actions to different impact forces. The mechanism 55, 57, 59, by which stop bar 51 is turned, is not shown in FIGS. 4 and 5. The links 6 and 4, by which control bar 1 is connected with the case shift means are provided for control bars 123 and 97 in the embodiments of FIGS. 4 and 5, but not shown for the sake of simplicity.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of apparatus for adjusting the impact force of types differing from the manner described above.

While the invention has been illustrated and described as embodied in a control bar having a lowercase abutment and an uppercase abutment for simultaneously setting all type actions, which are individually adjusted by resilient stop means, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

1. Apparatus for adjusting the impact force of types, comprising: a power roll; a row of type actions, each type action including a type bar having a lowercase type face and an uppercase type face, a driven lever, and coupling means movably mounted on said driven lever and cooperating with said power roll so that said driven lever is accelerated until said coupling means separates from said power roll and said driven lever freely moves in an inertia movement along a path for moving said type bar toward a printing position; case shift means having a lowercase position and an uppercase position for rendering said lowercase type face and said uppercase type face operative, respectively; adjustable resilient stop means correlated with said type actions located in the path of the respective driven lever for terminating its free inertia movement; a unitary control bar extending across said type actions and having a row of fixed lowercase abutments and a row of fixed uppercase abutments forming part of said control bar and adapted to engage said resilient stop means, the radial heights of said abutments corresponding to the areas of the respective type faces, pairs of said lowercase and uppercase abutments being angularly spaced from each other and having different radial heights corresponding to the areas of the associated lowercase and uppercase type faces, means mounting said control bar for angular movement, and means connecting said case shift means with said unitary control bar for turning said control bar between a lowercase position in which said lowercase abutments are in an operative position adapted to engage said resilient stop means, and an uppercase position in which said uppercase abutments are in an operative position adapted to engage said resilient stop means, the abutments in said operative position cooperating with parts of said type actions, respectively, to determine the length of the inertia stroke of said driven levers so that said driven levers move different distances in said inertia movement, and said lower and upper type faces exert different impact forces when said lowercase abutments and said uppercase abutments of different radial height are in said operative position, respectively; and a separate turnable eccentric stop bar engaging said resilient stop means for adjusting the same.

2. Apparatus for adjusting the impact force of types, comprising: a power roll; a row oftype actions, each type action including a type bar having a lowercase type face and an uppercase type face, a driven lever, and coupling means movably mounted on said driven lever and cooperating with said power roll so that said driven lever is accelerated until said coupling means separates from said power roll and said driven lever freely moves in an inertia movement along apath for moving said type bar toward a printing position; case shift means having a lowercase position and an uppercase position for rendering said lowercase type face and said uppercase type face operative, respectively, an adjustable resilient stop means correlated with each type action and located in the path of the respective driven lever for terminating its free inertia movement, each adjustable resilient stop means including a spring finger and an adjustable screw engaging said spring finger for varying the tension thereof; a unitary control bar extending across said type actions and having a row of fixed lowercase abutments and a row of fixed uppercase abutments forming part of said control bar and adapted to engage said spring fingers, the radial heights of said abutments corresponding to the areas of the respective type faces, pairs of lowercase and uppercase abutments being angularly spaced from each other and having different radial heights corresponding to the areas of the associated lowercase and uppercase type faces, means mounting said control bar for angular movement, and means connecting said case shift means with said control bar for turning said control bar between a lowercase position in which said lowercase abutments are in an operaiive position adapted to en- 9 gage said spring fingers, and an uppercase position in which said uppercase abutments are in an operative position and adapted to engage said spring fingers, the abutments in said operative position engaging the respective spring fingers for varying the tension thereof, said spring fingers cooperating with parts of said type actions, respectively, to determine the length of the inertia movement of said driven levers so that said driven levers move different distances in said inertia movement, and said lowercase and uppercase type faces exert different impact forces when said lowercase abutments and said uppercase abutments of different radial height are in said operative position, respectively; and a separate turnable eccentric stop bar engaging said spring fingers for adjusting the same.

3. Apparatus as claimed in claim 2 wherein each spring finger consists of a plurality of superimposed leaf springs.

4. Apparatus as claimed in claim 3 wherein said stop means include a spring comb whose prongs are formed by said spring fingers.

5. Apparatus as claimed in claim 2 wherein said coupling means is said part of'said type action so that said coupling means is engaged and separated from said power roll, by the abutment which is in said operative position whereby said inertia movement of said driven lever is started at different moments when different abutments are in said operative positions.

6. Apparatus as claimed in claim 2 wherein said control means includes a control bar, and wherein said lower and uppercase abutments are rows of adjustable screws, respectively, whereby a pair of screws cooperates with each type action.

7. Apparatus as claimed in claim 2 comprising a keyboard; and wherein said adjustable stop means are located under said keyboard accessible from the front of thesame.

Claims (7)

1. Apparatus for adjusting the impact force of types, comprising: a power roll; a row of type actions, each type action including a type bar having a lowercase type face and an uppercase type face, a driven lever, and coupling means movably mounted on said driven lever and cooperating with said power roll so that said driven lever is accelerated until said coupling means separates from said power roll and said driven lever freely moves in an inertia movement along a path for moving said type bar toward a printing position; case shift means having a lowercase position and an uppercase position for rendering said lowercase type face and said uppercase type face operative, respectively; adjustable resilient stop means correlated with said type actions located in the path of the respective driven lever for terminating its free inertia movement; a unitary control bar extending across said type actions and having a row of fixed lowercase abutments and a row of fixed uppercase abutments forming part of said control bar and adapted to engage said resilient stop means, the radial heights of said abutments corresponding to the areas of the respective type faces, pairs of said lowercase and uppercase abutments being angularly spaced from each other and having different radial heights corresponding to the areas of the associated lowercase and uppercase type faces, means mounting said control bar for angular movement, and means connecting said case shift means with said unitary control bar for turning said control bar between a lowercase position in which said lowercase abutments are in an operative position adapted to engage said resilient stop means, and an uppercase position in which said uppercase abutments are in an operative position adapted to engage said resilient stop means, the abutments in said operative position cooperating with parts of said type actions, respectively, to determine the length of the inertia stroke of said driven levers so that said driven levers move different distances in said inertia movement, and said lower and upper type faces exert different impact forces when said lowercase abutments and said uppercase abutments of different radial height are in said operative position, respectively; and a separate turnable eccentric stop bar engaging said resilient stop means for adjusting the same.

2. Apparatus for adjusting the impact force of types, comprising: a power roll; a row of type actions, each type action including a type bar having a lowercase type face and an uppercase type face, a driven lever, and coupling means movably mounted on said driven lever and cooperating with said power roll so that said driven lever is accelerated until said coupling means separates from said power roll and said driven lever freely moves in an inertia movement along a path for moving said type bar toward a printing position; case shift means having a lowercase position and an uppercase position for rendering said lowercase type face and said uppercase type face operative, respectively, an adjustable resilient stop means correlated with each type action and located in the path of the respective driven lever for terminating its free inertia movement, each adjustable resilient stop means including a spring finger and an adjustable screw engaging said spring finger for varying the tension thereof; a unitary control bar extending across said type actions and having a row of fixed lowercase abutments and a row of fixed uppercase abutments forming part of said control bar and adapted to engage said spring fingers, the radial heights of said abutments corresponding to the areas of the respective type faces, pairs of lowercase and uppercase abutments being angularly spaced from each other and having different radial heights corresponding to the areas of the associated lowercase and uppercase type faces, means mounting said control bar for angular movement, and means connecting said case shift means with said control bar for turning said control bar between a lowercase position in which said lowercase abutments are in an operative position adapted to engage said spring fingers, and an uppercase position in which said uppercase abutments are in an operative position and adapted to engage said spring fingers, the abutments in said operative position engaging the respective spring fingers for varying the tension thereof, said spring fingers cooperating with parts of said type actions, respectively, to determine the length of the inertia movement of said driven levers so that said driven levers move different distances in said inertia movement, and said lowercase and uppercase type faces exert different impact forces when said lowercase abutments and said uppercase abutments of different radial height are in said operative position, respectively; and a separate turnable eccentric stop bar engaging said spring fingers for adjusting the same.

3. Apparatus as claimed in claim 2 wherein each spring finger consists of a plurality of superimposed leaf springs.

4. Apparatus as claimed in claim 3 wherein said stop means include a spring comb whose prongs are formed by said spring fingers.

5. Apparatus as claimed in claim 2 wherein said coupling means is said part of said type action so that said coupling means is engaged and separated from said power roll, by the abutment which is in said operative position whereby said inertia movement of said driven lever is started at different moments when different abutments are in said operative positions.

6. Apparatus as claimed in claim 2 wherein said control means includes a control bar, and wherein said lower and uppercase abutments are rows of adjustable screws, respectively, whereby a pair of screws cooperates with each type action.

7. Apparatus as claimed in claim 2 comprising a keyboard; and wherein said adjustable stop means are located under said keyboard accessible from the front of the same.

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