US1802391A - Typewriting machine - Google Patents

Description

Apr;1 28, 1931- A. E. OSWALD I 1,802,391

TYPEWR ITING MACHINE Filed July 15, 1926 4 Sheets-Sheet l In ven for:

Aria/nay April 28, 1931- A. E. OSWALD 1,802,391

TYPEWRITING MACHINE Filed July 15; 1926 4 Sheets-Sheet 2 lm/emor:

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Afro/we April 28, 1931. A. E. 'OSWALD TYPEWRITING MACHINE Filed July 15, 1926 4 Sheets-Sheet 3 In vemor':

Afro/we April 28, 1931. A. E. OSW ALD TYPEWRITING MACHINE Filed July 15, 1926 4 Sheets-Sheet 4 Hfforney Patented Apr. 28, 1931 UNITED STATES PATENT OFFICE ALFRED E. OSWALD, 0F EACKENSACK, NEW JERSEY, ASSIGNOR TO UNDERWOOD EL- LIOTT FISHER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE TYPEWRITING MACHINE Application filed July 15,

This invention relates to mechanically operated typewriting machines in which the keys are depressed part way to set the typebar driving mechanism.

It has been proposed to operate the typebars by means of a complicated cam-mechanism.

It is one of the objects of this invention to simplify the driving of the type-bar. There is provided a continuously revolving shaft of iron or the like, which is surrounded by an electromagnetic coil'through which an electric current is caused to flow. The shaft protrudes at both ends of the coil and co-operates with a U-shaped armature straddling the coil and contacting with the shaft. The armature is mounted on a sliding member which carries a cross-bar designed to engage a pawl operatively connected to each type-bar, and uponoperation of a type-key the pawl is thrown in the path of the slide which picks it up and swings the type-bar. The depression of a key is also effective to close an electric circuit through the coil in a manner to magnetize the shaft and to consequently generate a magnetic fiow through the shaft which attracts the armature and rolls it on the shaft. This, of course, will move the slide upon which the armature is mounted and the type-key which has been partly depressed will be automatically swung to its typing position. When the slide reaches the end of its travel, the electric circuit through the coil is interrupted and the slide is returned to its normal position by means of a spring. The magnetic flux between the magnetized revolving shaft and its associated armature is great and although the attraction, and consequent friction of the two members, is constant, the driving power of the shaft may be increased by increasing its speed. The speed may also be controlled to determine the force of the type blows against the platen.

' It will be understood that owing to the peculiar construction of the Underwood type- 1926. Serial No. 122,537.

action the key-depression is very light at the beginning of the stroke and increases gradually as the key is further depressed. In this invention advantage is taken of this condition. The first portion of the key depression is used to set the driving mechanism, which is subsequently effective to completely swing the type-bar associated with the key.

According to one feature of the invention,

means are provided to limit the depression of the keys to thereb improve their touch by preventing the col apsing of the keys under the fingers. To this end there is provided a special keyboard overlying the regular keydepressing the type-keys, which are picked by I the driving mechanism after being partly depressed.

Another feature of this invention relates to means for rendering the typewriting machine manually operable. when the electric power is cut off. To this end there is provided a depressible button which moves the operating slide to ineifective position. The machine may be removed from its driving mechanism in case it is desired to operate it by hand while the electric power is cut ofi'.

This invention may be used in connection with typewriting machines having a carriagereturn mechanism of the type disclosed in the patent to Henry LQPitman, No. 1,580,326, dated April 13, 1926. However, since it is desired to rotate the electric motor continuously to drive the type-keys, the starting switch with which the carriage-return mechanism is usually provided is eliminated, and

the motor lead wires are connected to terminal blocks in the driving mechanism.

The slide which operates the type-bars is mechanically returned to its normal position by means of a spring. In'case of accidental misuse of the machine the slide may not reach the end of its travel in which case the circuit would remain closed and the parts would be strained. In this invention means are provided whereby the circuit may be opened by depressing a button to thus permit the slidereturning spring to actuate and to normalize the machine.

Owing to the enormous scale in which typewriting machines are made, even slight changes in the design of simple parts are costly because they always involve the discarding and building of tooling equipment. In view of this it is considered an important feature of this invention that a standard machine may be taken out of stock and transformed into an electric typewriter by simply attachin a few clamps to the type-keys. Thus, old machines be electrically driven by simply purchasing an inexpensive base into which the driving mechanism is built.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a cross-sectional view, in eleva-' tion, of an Underwood typewriting machine having the automatic type-key-driving mechanism applied thereto.

Figure 2 is a cross-sectional view through line 22 of Figure Figure 3 is a plan View of the driving mechanism with the machine removed.

Figure 4 is a cross-sectional view through line 4-4 of Figure 1, showing the back of the typewriter and the carriage-return mechamsm.

Figure 5 is a cross-sectional view through line 5-5 of Figure 3.

Figure 6 is a cross-sectional view through line 6-6 of Figure 3.

Figure 7 shows one form of the invention in which a clamp is provided for utilizing a standard key-lever.

Figure 8 is a detail cross-sectional view, showing a brush contacting with the rotating driving shaft.

Figure 9 is an operating view, showing one of the key-levers partly depressed, the temporary switch being closed.

Figure 10 is an operating view, showing a type-bar partly swung by the action of the driving mechanism.

Figure 11 shows one form of the invention in which a special keyboard is provided to limit the depression of the keys.

Figure 12 is a diagrammatic view, showing the electrical connections.

The Underwood typewriting machine is provided with a traveling carriage 20, upon which a platen 21 isrotatably mounted. The

carriage is slidably mounted on rails 22 and 23, and its traveling movement is controlled by means of escapement-mechanism 24. The escapement-mechanism is operated by a universal bar 25, which is struck by type-bars 26 operatively connected to depressible keys 27. The keys are mounted at the ends of levers 28 pivotally mounted on a shaft 29 and operate a bell-crank 30, which swings the typebars.

Owing to the peculiar construction of this type-action, the key-depression is very light at the beginning of the stroke, but it gradually becomes harder as the key is further depressed. It is one of the objects of this invention to mechanically operate the type-bars during the time when the depression of the keys is harder. To this end, each type-bar is provided with a bell-crank 31 pivotally mounted on a cross-shaft 32, which is fast to the frame of the machine 33 by. means of screws 34. One end of the bell-crank is provided with an elongated slot 35, which engages a pin 36 carried by the lever 28. The lower arm of the bell-crank 31 extends downwardly and carries at the end thereof a pawi 37 fast to a stud 38 pivotally mounted on the arm. Said pawl is normally held in the position shown in Figure 1 by means of a spring 39. It will be understood that there is one bell-crank for each key, as shown in Figure 2.

The key-driving mechanism is mounted on a base 40 under the typewriter and includes a slide 11 mounted on supporting studs 42 and 43 fast to the base 40. The slide is held in place by means'of screws 4: 1 and carries a cross-plate 45 fast to the slide by means of rivets 46. The cross-plate extends the full width of the machine, the forward end thereof being bent upwardly to form a ledge or hook 47. The slide is held in its normal position, as shown in Figure 1, by means of a spring 48 mounted on a spring-stud 49 and fast to the end of the slide.

In order that the slide 41 may be automatically reciprocated upon depression of any one of the keys, there is provided a rotating shaft 50 made of magnetizable material, such as'soft iron, supported on insulated brackets 51. The rotating movement is imparted to the shaft by means of an electric motor 52 and a driving mechanism including pulley 53 and 54, and a belt 55., The pulley 54 is fast to the shaft by means of a screw 56, while the pulley 53 is mounted on a motor shaft 57. The shaft 50 is surrounded with anelectromagnetic coil 58mounted onthe base by means of end brackets 59 and screws 60. This coil is effective to magnetize the shaft when an electric current is caused to flow therethrough.

The operating connection between the rotating shaft 50 and the slidedl includes a plate 61 slidably mounted on the slide 41 and held in its normal position by means of a spring 62 mounted between spring-studs 63 and 64. The spring-stud 63 has a flange which serves as means for guiding the sliding plate 61 and cooperates with another stud 65,

which is slidably mounted on the slide 41. The end of the plate 61 is provided with a bracket 66 fast thereto by means of a screw 67 surrounded with insulating material 68,

ture is held in the position shown in Figure 1 by gravity, and is supported by pins 71 fast to the brackets 59. It will be noted that there is a gap between the shaft and the armature, so that when the shaft is rotating the armature is not affected by its rotation until the shaft is magnetized. The armature is of U-shaped construction and straddles the coil 58 so as to contact with the shaft at both sides of the coil, thus providing for a maxifn'um magnetic flow and a maximum adherence of the armature to the shaft.

Each key-lever is depressed in a manner to swing the bell-crank 31 so that the rear end 72 of the pawl 37 will strike a bail-,piece 73 pivotally mounted on a stud 75 carried by bent ends 74 of the cross-plate 45. The bent ends slide on the base and serve as a means for laterally positioning the slide 41. Said bailpiece is held in the position shown in Figure 1 by means of springs 76 carried by studs 77 and 78. These springs are stronger than the spring 39, and, for this reason, upon swinging the bell-crank 31, the pawl 37 will be swung to the position shown in Figure 9. However, upon swinging the bell-crank 31 further, the tension of thespring 7 6 will be overcome, thereby swinging the bail-piece 73 to the position shown in Figure 9. The bail-piece is effective to close a switch 79, which temporarily magnetizes the shaft 50 by closing an electric circuit through terminals 80, 81 and 82, the coil 58 and the terminals 83 and 84. The current also flows through a switch 85, the construction and purpose of which will be explained later.

The flow of current through the circuit just described, and shown in Figure 12, is effective to magnetize the shaft 50 which attracts the armature 70 as shown in Figure 10. When the armature is attracted by the shaft a magnetic circuit is closed which flows through the armature and through the shaft. This powerful attraction between the shaft and the armature is effective to roll the armature on the shaft, thereby moving the operating slide 41 rearwardly, as indicated by the arrow in Figure 10, but since thepawl 37 has been swung in the path of the slide 41, the pawl will be picked up by the slide in a manner to swing the bell-crank 31, and thereby complete the depression of the typekey 27 associated with the bell-crank.

After the slide 41 reaches the end of its travel it is necessary to interrupt the circuit so as to permit the spring 48 to retract the slide to its normal position. In order to facilitate the breaking of this circuit, it is proposed to short circuit the current as indicated by dotted lines 86 in Figure 12, when the armature contacts with the shaft 50, which in turn contacts with a brush 87 at the top thereof. Said brush is mounted on a block 88 of insulating material, which is secured to the base 40 by means of a screw 89, and serves also as a terminal-block for the negative side of the main and motor circuit. It will be understood from the foregoing that when the armature is attracted by the shaft, the current does not flow through the terminal 80, but through the brush 87, the shaft 50, the armature 70, through the coil 58 which is connected to the armature by means of a screw 90, and out of the coil through terminal 83, switch 85, and terminal 84. Immediately after the slide 41 starts moving, the switch 79 is opened by the action of the spiing 76. It is then only necessary to interrupt the last-mentioned circuit in order to demagnetize the shaft 50, and to permit the actuation of the spring 48. To this end there is provided a plate 91 of insulating material which overlies the armature 70 and interposes the shaft and the armature when the latter reaches the end of its travel, to thereby interrupt the electrical connection between the shaft and the armature. In order to pro tect the wearing surface of the plate 91, which is of soft material, there may be provided an overlying plate 92 of sheet-metal. plates are fast to the armature by means of screws 93.

The switch 85 serves as a means for holding the main line normally closed, and for facilitating the manual temporary interruption of the current in case the type-bars or any part of the mechanism gets jammed. The switch, which is fully illustrated in Figure 3, is mounted on a block of insulating material 94, fast to the base by means of screws 95. One end of the terminal 84 is fastened to the block by means of a screw 96 and a Both nut 97. The head of the screw 96 contacts 1 key. The spring 98 is bent rearwardly to the position shown in dot-and-dash lines in Figure 3. The movement of the bar 103 is limited by means of a pin 104 and two prongs 105 forming an integral part of the bar. The other end of the bar is fitted in a slot in the block and is held in place by the head of one the screws 95.

One of the advantages of this invention is 3 that the machine may be manually operated, when desired, in case the electrical power is cut off. To this end means are provided whereby the operating slide 41 may be moved rearwardly so as to permit the unobstructed swinging movement of the bell-crank 31. The

slide may be moved by means of a key 106, mounted at the end of a link 107, which is connected by means of a pin 108 to an arm 109 pivotally mounted on a shoulder-screw 110 fast to the base as shown in Figure 6. The end of the arm 109 is operatively connected to operate the slide by means of a stud 111. The link 107 may be latched in its operated position by engaging a notch 112 against the edge 113 of a slot in the base through which the link protrudes to the outside of the casing.

The power required for driving the shaft 50 is supplied by the electric motor 52 which serves also as the motive power for returning the carriage. The end of the motor-shaft 57 carries a worm 114 which engages with a worm-gear 115 fast to a shaft 116 journaled on a supporting bracket 117. The inner end of the shaft 116 carries a gear 118 which engages with a rack 110 mounted on the carriage 20. The gear 118 is slidably mounted on the shaft 116 and may be moved into engagement with teeth 120 of a clutch-member 121, said clutch-member being fast to the shaft 116. The means for sliding the gear 118 is not shown in this invention, but is fully illustrated in said patent to Pitman.

The switch indicated generally by the numeral 79 serves as a means for temporarily closing the circuit through the coil 58 so as to magnetize the shaft 50 which attracts the armature and closes the main circuit. It will be understood that a switch of any approved design could be used for this purpose. In the design adopted, there is provided a pair of blocks of insulating material 122 upon which spring-leaves 123 are mounted by means of screws 124 and nuts 125. The screws are insulated from the slide 41 by means of washers 126. Each leaf carries, at the end thereof, contact points 12 Tthrough which the current passes when the two contact points are short circuited by means of a metal-plate 128 which may be provided with contact points 129 to eliminate sparking. Said plate 128 is carried by the bail-piece 73 to which it is secured by means of screws 130 and an intervening plate 131 of insulating material.

In order that a standard typewriting machine of the Underwood type may be utilized in connection with this invention, there may be provided a series of clamps of the type illustrated in Figure 7. Said clamps are secured to the key-levers 28 in a position such as shown in dot-and-dash lines in Figure 1 by means of a shoulder-screw 132 which takes the place of the pin 36 shown fast to the keylever of special construction. The screw 132 is also effective to hold a bracket 133 in place by means of a brace 134 which receives the screw 132.

The key-depression may be limited when desired by means of a special keyboard shown in Figure 11. The keyboard is provided with keys 135 having stems slidably mounted in holes in a frame consisting of an upper plate 136 and a lower plate 137, both plates being held together by means of rivets 138. The frame is fitted to the machine-frame and the ends 139 of the key-stems are upset or enlarged to prevent accidental displacement of the keys. In order to prevent clicking of the special keys, there may be provided felt Washers 140 which limit the key-depression. It will be understood that the machine is operable without the special keyboard, but then the depression of the regular keys is not limited.

The motor 50 is provided with leads 141 and 142, which are secured to the terminalblocks 88 by means of screws 143. Supply leads 144 and 145 are also secured to the terminal-blocks by means of the screws 143. The main line may be provided with a snapswitch 146 to cut off the current. This switch may be secured to the machine near the keyboard to facilitate its operation.

. Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. A power-driven typewriting machine including type-bars, depressible type-keys associated with the type-bars, and means for automatically completing the depression of the keys, to thereby operate the type-bars after the keys have been partly depressed, said means including a continuously revolving shaft, means controlled by the keys to magnetize said shaft, and an armature c0- operating with the shaft, said armature being operatively connected with the partlydepressed key in a manner to swing the typebar associated with the depressed key.

2. An automatic typewriting machine including, in combination, type-bars, depressible type-keys therefor, key-driving mechanism, and means controlled during the first part of the key-depression for setting the driving mechanism, said key-driving mechanism including an operating slide, means for operatively connecting the slidewith thepartly-depressed key, and means for reciprocating the slide, said last-mentioned means including a spring for holding the slidiin its normal position, an armature pivotally mounted on the slide, a revolving magnetizable shaft co-operating with said armature, means, controlled by the key being depressed, for closing an electrical circuit effective to magnetize said shaft, the shaft being effective to attract the armature and to roll it thereon to thereby draw on the operating slide, and means for interrupting the flow of current, to thereby demagnetize the shaft and to permit retracting movement of the operating slide.

3. In a typewriting machine having typebars and depressible keys therefor, means controlledduring the first portion of the keydepression for automatically completing the depression of the key, said means including a bell-crank operatively connected with each key, a pawl carried by each bell-crank, a sliding member, a source of power, and means for swinging the pawl associated with the bell-crank in the path of the sliding member, said last-mentioned means being also effective to connect the sliding member with the source of power.

4. The combination of means forautomatically driving the keys and type-bars of a typewriting machine, said means including, in combination, an operating slide, a revolving shaft, an electromagnetic coil surrounding the shaft, the latter protruding at the ends of the coil, an armature carried by the slide, said armature straddling the coil and being normally held in close proximity'to the v shaft, and means for selectively connecting the keys with the slideand for causing the coil to magnetize the shaft in a manner to attract the armature and to roll it thereon, to thereby move the slide therewith.

5. The combination with a typewriting machine having a traveling carriage, typebars, and type-keys therefor, of a continuously running motor, mechanism operatively connected to the motor for returning the carriage, and electromagnetic means co-operative with said motor to automatically drive the type-bars upon partly depressing the type-keys.

6. In a typewriting machine having typebars and depressible keys therefor, means controlled during the first portion of the keydepression for automatically completing the depression of the key, said means including a bell-crank operatively connected with each key, a pawl carried by each bell-crank, a sliding member, a source of power, a revolving shaft of magnetic material running on insulated bearings, an electromagnetic coil surrounding the shaft, a by-pass armature of magnetic material for closing a magnetic circuit through the shaft and the armature, said armature being pivotally mounted on said sliding member, and means for swinging the pawl associated with the bell-crank in the path of the sliding member, said lastmentioned means being also effective to initiate a flow of electrical current through the coil.

7 A power-driven mechanism for the type-bars of a typewriting machine including, in combination, an operating slide, an armature of magnetic material carried by said slide, a revolving shaft of magnetic material, co-operating with said armature to roll it on the shaft, means for magnetizing said shaft during the first portion of the key-depression, and means for moving an interposing member in the path of the slide during the first portion of the key-depression, said interposing member being effective to swing the type-bar associated with the partly-depressed key upon operation of the slide.

8. A power-driven mechanism for the typebars .of a typewriting machine including, in combination, an operating slide, an armature of magnetic material carried by said slide, a revolving shaft of magnetic material, co-operating with said armature to roll it on the shaft, means for magnetizing said shaft during the first portion of the key-depression, means for moving an interposing member in the path of the slide during the first portion of the key-depression, said interposing member being effective. to swing the type-bar associated with the partly-depressed key upon operation of the slide, means controlled by the slide for causing the shaft to be demagnetized in a manner to permit retracting movement of the slide, and a spring to retract the slide to normal position.

9. A power-driven mechanism for the type-bars of a typewriting machine including, in combination, an operating slide, an armature of magnetic material carried by said slide, a revolving shaft of magnetic material, co-operating with said armature to roll it on the shaft, means for magnetizing said shaft during the first portion of the key-depression, means for moving an interposing member in the path of the slide during the first portion of the keydepression, said interposing member being effective to swing the type-bar associated with the partly-depressed key upon operation of the slide, means controlled by the slide for causing the shaft to be demagnetized in a manner to permit retracting movement of the slide, and means for returning the slide to its normal position.

10. A power-driven mechanism for a typewriting machine having type-bars and keylevers therefor, said mechanism including, in combination, an operating slide having a keylever-driving cross-bar, an interposing member vibrated by each key-lever into the path of the slide during the first portion of a keydepression, and means for conveying motion to the slide, said means including a revolving shaft, an armature adjacent the shaft but levers therefor, said mechanism including, in combination, an operating slide having a keylever-driving cross-bar, an interposing member movable by each key-lever into the path of the slide during the first portion of a key depression, means for conveying motion to 'the slide, said meansincludmg a revolving shaft, an armature adjacent the shaft but spaced therefrom, an electromagnetic coil surrounding the shaft," a source of electric power, and a switch for temporarily closing an electrical circuit through the coil, said switch being closed by any one of the keys during the first portion of their, depression, and means for short circuiting the current through the shaft and through the armature when the latter is attracted by the'shart.

12. A power-driven mechanism for a typewriting machine having type-bars and keylevers therefor, said mechanism including, in

' combination, an operating slide having a keylever-driving cross-bar, an interposing member movable by each key-lever mto the Path of the slide during the first portion of the key-' depression, means for conveying motion to the slide, said means including a revolving shaft, an armature adjacent the shaft but spaced therefrom, an electromagnetic coil surrounding the shaft, a source of electric power, and a switch for temporarily closing an electrical circuit through the coil, said switch being closed by any one of the keys during the first portion of their depression, and means for short circuiting the current through theshaft and through the armature when the latter is attracted by the shaft, said last-mentioned means including a terminalblock, and a brush carried by the terminalblock and contacting with the shaft-x 13. A power-driveirmechanism for a type- "writing machine having type-bars and keylevers therefor, said mechanism including, in combination, an operating slide, an interposing member movable by each key-lever into the aath of the of tlie key-depression, means for conveying motion to the slide to drive the key-levers,

- said means including a revolving shaft, an

armature adjacent the shaft but spaced therefrom, an electromagnetic coil surrounding the shaft, a'source of electric power for exciting the coil, and a switch for temporarily closing an electrical circuit through; the coil, said switch being closed by any one of the keys during the first portion of their depression, means for short circuiting the current through the shaft and through the armature when the latter'is attracted by the shaft, and

means for "automatically interrupting the determined position.

14. A power-driven mechanism for a type writing machine having type-bars and keylevers therefor, said mechanism including, in combination, an operating slide, in interposing member movable by each key-lever into the path of the slide during the first portion of the key-depression, means for conveying motion to the slide, to drive the key-levers, said means'including a revolving shaft, an armature adjacent the shaft but spaced therefrom, an electromagnetic coil surrounding the shaft, :1 source of electric power, and a switch for temporarily closing an electrical circuit'through the coil, said switch being closed by any one of the keys during the first portion of their depression, means for short circuiting the current t'hroughthe shaft and through the armature when the latter is attracted by the shaft, and means for automatically interrupting the electrical circuit when the slide reaches a predetermined position, said last-mentioned means including a thin plate of insulating material movable with the armature to become effective to separate the armature from the shaft.

15. A typekey-driving mechanism for a typewriting machine having type-bars and type-keys therefor, said mechanism including, in combination'a bell-crank associated with each key, a pawl carried by each bellcranl an ol'ieratingslide having a ledge arranged to engage the pawl carried by the depressed key only, a normally open switch, a bail-piece operable by any one of the pawls upon'operation of its associated bell-cranli to close the switch, and an electromagnet whose circuit is controlled by said switch, said magnet including a revolving shaft operable to attract said slide upon closingof said switch and move the same to cause it to engage the pawl thrown in its path'by the partly-depressed key in a manner to complete the depression of the key and the swinging ofits associated type-bar to type.

16. A type-key-driving mechanism for a typewriting machine having type-bars and ing, in combination, a bell-crank associated Slide during the first POI'tiOII with each key, a pawl carried by each bell-r crank, an operating slide having a ledge arranged to engage the pawl carried by the depressed key only, a bail-piece operable by any one of the bell-cranks upon operation of itsiassociated key, said bail-piece being carried by the slide, a normally open switchhaving one terminal on said bail-piece and closable, upon swinging the bell-crank, to move the bail-piece, and means, controlled by said switch, for driving the slide to thereby cause the complete depression of the partly-depressed key and its associated type-bar.

17. A type -key-driving mechanism for it ewritin machine havin t )e-b d electrical clrcuitswhen the slide reachesapreyp g b yl an type-keys therefor, said mechanism including, in combination, a bell-crank associated with each key, a pawl carried by each bellcrank, an operating slide having a ledge arranged to engage the pawl carried by the de' ressed key only, a bail-piece operable by any one of the bell-cranks upon operation of its associated key, said bail-piece being carried by the slide, a normally open switch having one terminal on said bail-piece and closable upon swinging the bell-crank, to move the bail-piece, means, controlled by said switch, for driving the slide to thereby cause the complete depression of the partly-depressed key and its associated type-bar, said means including a revolving iron shaft, an iron armature associated with the shaft, said armature being pivotally mounted on the slide and being in close proximity to the shaft, and an electromagnetic coil surrounding the shaft, the electrical circuit being closed through the coil and the switch to magnetize the shaft and its associated armature, and means for restoring said slide to normal position.

18. A type-key-driving mechanism for a typewriting machine having type-bars and type-keys therefor, said mechanism including, in combination, a bell crank associated with each key, a pawl carried by each bellcrank, an operating slide having a ledge arranged to engage the pawl carried by the depressed key only, a bail-piece operable by any one of the bell-cranks upon operation of its associated keys, said bail-piece being carried by the slide, a normally open switch having one terminal on said bail-piece and closable, upon swinging the bell, to move said bailpiece means, controlled by said switch, for driving the slide to thereby cause the complete depression of the partly-depressed key and its associated type-bar, said means including a revolving iron shaft, an iron armature associated with the shaft, said armature being pivotally mounted on the slide and being in close proximity to the shaft, and an electromagnetic coil surrounding the shaft, the electrical circuit being closed through the coil and the switch to magnetize the shaft and its associated armature, means for interrupting the electrical circuit when the slide which is rolled on the shaft reaches a predetermined position, and means for restoring the slide to its normal position.

19. In a typewniting machine having type-bars, depressible type-keys associated with said type-bars, and depressible keylevers connected to said bars and keys, the combination of a continuously rotating shaft, means for depressing said key-levers, a unit actuating member for operating said means, including a driven slide and a keylever-driving cross-bar, means set into operation upon the partial depression of a key to effect coupling between said shaft and said actuating member to cause said firstmentioned means to completethe depression of the corresponding key-lever to swing the associated type-bar to typing position, and means for restoring said actuating member to normal position.

20. In a typewriting machine having type-bars, type-keys, and depressible keylevers connected to said bars and keys, the combination of a continuously rotating shaft, means for depressing said key-levers, a single actuating member for operating said means, electromagnetic means set into operation upon partial depression of a key to effect coupling between said shaft and said actuating member to cause said first-mentioned means to complete the depression of the corresponding key-lever to swing the associated type-bar to typing position, and means for restoring said actuating member to normal position.

21. In a typewriting machine having type-bars, type-keys, and depressiblekeylevers connected to said bars and keys, the combination of a continuously rotating shaft, means for depressing said key-levers, a single actuating member for operating said means, electromagnetic means set into operation upon partial depression of a key to effect coupling between said shaft and said actuating member, to cause said firstmentioned means to complete the depression of the corresponding key-lever to swing the associated type-bar to typing position, means for rendering said electromagnetic means inoperative, and means for restoring said actuating member to normal position.

22. In a typewriting machine having type-bars, type-keys, and depressible keylevers connected to said bars and keys, the combination of a key-lever-actuating memher, an electromagnet including a cylindrical core spaced from said actuating member, means for rotating said core, a switch operable upon partial depression of a key to close an electric circuit exciting said electromagnet to attract the actuating member to said core, and means connected to the key-levers and placed in the path of the actuating member upon partial depression of a key, to cause complete depression of the corresponding key-lever to swing the associated typebar to typing position.

23. In a typewriting machine having type-bars, type-keys, and depressible keylevers connected to said bars and keys, the combination of a key-lever-actuating member, an electromagnet including a cylindrical core spaced from said actuating member, means for rotating said core, a switch operable upon partial depression of a key to close an electric circuit exciting said electromagnet to attract the actuating member to said core, means connected to the key-levers and placed in the path of the actuating member to cause complete depression of the partially-depressed key-lever to swing the associated type-bar to typing position, and means for returning said actuating member to normal position, including means rendered operative by the movement of said actuating member by said core to break the exciting electric circuit to. release the actuating member from said core.

24. In a typewriting machine having type-bars, type-keys, and depressible keylevers connected to said bars and keys, the combination of a key-lever-actuating member including an armature, an electromagnet including a cylindrical core spaced from said actuating armature, means for rotating said core, a switch operable upon partial depression of a key to close an electric circuit to excite said electromagnet and attract the actuating armature to said core, means connected to the key-levers and placed in the path of the actuating member to cause complete depression of the partially-depressed key-lever to swing the associated type-bar to typing position, and means for returning said actuating member to normal position, including means for short-circuiting the exciting current through the core upon contact of the latter with the actuating armature, and for shunting the switch upon initial movement of said armature by said rotating core, and means rendered operative upon further movement of said armature to break the electric contact between said armature and said core.

25. In a key-operated machine, the combination with a depressible key, of means operable upon partial depression of said key to complete the depression thereof, said means including an instrumentality actuated upon depression of said key, a continuously rotating shaft, an excitable coil for magnetizing the shaft, an actuating member engageable with said instrumentality, and means operable upon partial depression of the key toexcite the coil and establish an electro-magnetic field for said rotating shaft to couple said actuating member and cause the actuating member to complete the movement of said instrumentality and its associated key.

26. In a key-operated machine, the combination with a depressible key, of means operable upon partial depression of the key to complete the depression thereof, said means including an instrumentality actuated upon depression of said key, a continuously rotating shaft, an excitable coil for magnetizing the shaft, a movable slide, a pawl connected to said instrumentality and movable upon partial depression of the key into the path of the slide, a normally open coil exciting circuit, a switch operable upon partial depression of said key to close said circuit to excite the coil and establish an electromagnetic field for the shaft effective to attract and couple said slide to said shaft, and thereby complete the movement of said instrumentality and its associated key through engagement of the slide with said pawl, and means for returning the slide to normal position.

bination with a depressible key, of means operable upon partial depression of the key to complete the depression thereof, said means including an instrumentality actuated upon depression of said key, acontinuously rotating shaft, an excitable coil for magnetizing the shaft, a movable slide, a pawl connected to said instrumentality and movable upon partial depression of the key into the path of the slide, a normally open coil exciting circuit, a switch operable upon partial depression of said key to close said circuit to establish an electromagnetic field for the rotating shaft effective to attract and couple said slide to said shaft, and thereby complete the movement of said instrumentality and its associated key through engagement of the slide with said pawl, means operable by the movement of the slide for shunting the coil exciting circuit to cut out the switch, without demagnetizing the coil, means movable with the slide for opening the coil exciting circuit to demagnetize the coil, and means for returning the slide to normal position.

28. The combination with a key-operated machine, an auxiliary keyboard'having keys arranged to overlie and contact the keys of the machine, means for limiting the depression of the keys of said auxiliary keyboard to substantially less than the stroke of the keys of the machine, and power means for automatically completing the depressions of the keys of the machine.

29. In a key-operated machine having keys and key-levers actuated thereby, the combination with a key-driving member for each key including a pawl moved by the key into the path of a driven member upon partial depression of the key, and power-driven means set in motion by the partial depression of said key to drive said member to complete the depression of the key, of manually-operated means for moving said member at will beyond the range of movement of said pawls to permit the manual operation of the machine wholly by the keys.

30. In a typewriting machine, the combination with a system of type-actions, each including a type-bar, of key-controlled electromagnetic means for operating any typeaction, said operating means including a reciprocatory common actuator and a revolving cylindrical device against which the common actuator may be magnetically drawn and held with force sufficient to enable the cylindrical device to drive the actuator in one direction, together with the selected type-bar, by means of friction between the cylindrical device and the actuator; and means for returning the actuator to normal position.

31. In a typewriting machine, the combination with a system of type-actions, each including a type-bar, of key-controlled electromagnetic means for operating any typeaction, said operating means including a reciprocatory common actuator and a revolving cylindrical device against which the common actuator may be magnetically drawn and held with force sufficient to enable the cylindrical device to drive the actuator in one direction, together with the selected type-bar, by means of friction between the cylindrical device and the actuator; and means brought into action by the actuator at the conclusion of the printing stroke, for automatically terminating the driving of said actuator by said cylindrical device.

32. In a typewriting machine, the combination with a system of type-actions, each including a type-bar, of key-controlled electromagnetic means for operating any typeaction, said operating means including a reciprocatory common actuator and a revolving cylindrical device against which the common actuator may be magnetically drawn and held with force sufficient to enable the cylindrical device to drive the actuator in one direction, together with the selected type-bar, by means of friction between the cylindrical device and the actuator, means brought into action by said actuator when driven by said cylindrical device, to automatically effect demagnetization of said electromagnetic means, thereby to release the operated actuator, and means to return the actuator to normal position independently of the cylindrical device.

33. In a typewriting machine, the combination with a system of type-actions, each including a type-bar, of a reciprocatory armature forming a driver universal to all the type-actions, and key-controlled electromagnetic means for operating the driver, said operating means including a revolving cylindrical device against which the armature is magnetically drawn and held with sufficient friction to enablethe cylindrical device to drive the armature together with the selected type-bar.

34. In a typewriting machine, the combi nation with a type-bar and a key, of electromagnetic means foroperating said type-bar, including a constantly-revolving magnetizable device, a reciprocatory actuator in the form of an armature, normally separated by a gap from said revolving device, means controlled by said key to magnetize said revolving device and thereby cause said armature to close said gap and to be magnetically held against the revolving device with force suflicient to enable the latter to drive the armature and type-bar by means of friction; means being provided for terminating the control of the revolving device over the armature and type-bar, and means to return the armature and type-bar to normal positions.

35. In a key-controlled typewriting machine having a power-driven shaft and a typeaction to be driven by the shaft, including a type-bar; an actuator, a member operated

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