US2283565A

US2283565A - Typewriting machine

Info

Publication number: US2283565A
Application number: US332538A
Authority: US
Inventors: Michelsen William Otto
Original assignee: Royal Typewriter Co Inc
Current assignee: Royal Typewriter Co Inc
Priority date: 1940-04-30
Filing date: 1940-04-30
Publication date: 1942-05-19
Anticipated expiration: 1959-05-19

Description

May 19, 1942. w. o. MlcHz-:LSEN

TYPEWRITING MACHINE Filed April 30, 1940 5 Sheets-Sheet l uw w Y .m s @MyW L R im M @J A Mvg@ uw www mw. mv 4 W u m .00 X www www Nm NNN @N QF@ N @NNN mm wm@ www E@ D@ .NQ l; f UHMWIVMIII mw mm RNW @ww mw. 4 Nl f. \@\mmw www NW mw if@ wm n ME e mw www w um @n 1 L; @D :O2 Nw mm NWNQQQ n l. e@ uwmwmwumm mwN Sw mmf@ @1 mw .mwr

May 19, 1942.

w. o. MlcHELsEN TYPEWRITING MACHINE FiledApril so, 1940 5 Sheets-Sheerl 2 INVENTOR Wil/iam O. Mieke/sew May 19, 1942 W. o1 MICHELSEN 2,283,565

TYPEWRITING MACHINE Filed April so, 1940 5 sheets-sheet s May 19, 1942.

Filed April 30,` 1940 W. O. MICHELSEN TYPEwRITNG MACHINE 5 sheets-sheet 4 @im l@ Q57 125 lNvENToR 129 $126 AWill/'afm O. Micha/sen ATTORNEYS May 19, 1942 vv. o. MICHELsx-:N

\ TYPEWRITING MACHINE Filed April so, 1940 5 Sheets-Sheet 5 Patented' May 19, 1942 untreu .STATES y PATENT oFFlcE.

TYPEWBITNG MACHINE William Otto Mlchelsen, Woodhaven, N.y Y., as-

signor to Royal Typewriter Company, Inc., New York, N. Y., a corporation of New Yorkz Application april 3o, 1940, `serial No. 332,533`

' 32 claims. ,(ci la7-s6) This invention relates to typewriting machines and more particularly to typewriter carriage driving. mechanism, especially carriage return driving mechanism.

An important object of the invention is to provide a simple, sturdy, typewriter carriage return mechanism capable of being inexpensively constructed and readily attached externally to the base frame of a typewriter in such a manner that it willnot interfere with the servicingof the usual `or standard typewriter mechanism.

Another object is to provide a power-driven typewriter carriage?` return mechanism controllable by a single key which may be adapted selectively, by means of a finger lever or other seriage return key momentarily. In some instances,

however, it is convenient to set the selector device to adapt the carriage return key to effect sustained carriage movement only during the or is greatly reduced just prior to the carriages reaching the extreme limit of its return travel, that is, just prior to the engagement of the carriage-mounted margin stop with the frame.

mounted center stop.

Another object is to provide shock absorbing means adapted to be effective' for retarding'the carriage only when the carriage is moved relatively rapidly and being ineffective to retard the carriage substantially when the carriage is `moved relatively slowly, as by hand.

Another object is to provide an improved and durable mechanism for transmitting drive from an electric motor or other power source to a typewriter carriage for eecting return move.

ment of the carriage, the drive connections being simple, certain lin operation and free from gears, special clutches, and other parts requiring time the key is held depressed. With this latter arrangemet/ the power-driven carriage return mechanism may be vcoordinated eiciently and conveniently with the use of tabulating mechanism such as is provided in standard typewriters.

Thus, during -tabulatingoperationa the carriage return key is held depressed to effect return of the carriage to a point just beyond the particular tabular stop which is to function inthe setting of the carriage for the next tabulating operation, and the carriage return key is then released, bringing the carriage to rest before it moves on to the extreme limit of its return travel. The usual tabular key is then depressed, causing the carriage to move a relatively short distance inletter spacing direction before it' is arrested by the tabular stop.- It is apparent that by' this arrangement considerable time is saved due to eliminating the useless continuing of the car- A riage to the limit of its return movement.

A further object is to provide an improved shock absorbing means adapted to retard the carriage as it approaches theY end of its return travel but the retarding action-of which ceases expensive machining, fitting and assembling operations.

Other objects will become apparent from a reading of the following description, the appended claims, and the accompanying drawings, in which:

Figure 1 is a plan view showing conventional parts of a typewriter with line spacing mechanism and with carriage return mechanism embodying the invention attached thereto;

Figure 2 is an end elevation of the typewriter and mechanism shown in Figure 1 Figure 3 is a partial rear view, mainly in elevation but with some parts in section, showing power-operated` carriage return mechanism andl carriage retarding or braking mechanism;

Figure 4 is a rear elevational viewof power driving and control mechanismv with parts broken away and some parts shown in section;

Figure 5 is a view in end elevation looking in the direction of the arrow 5 in Figure 4, with some parts broken away and others shown in section;

Figure 6 is afragmentary view, partly in lelevation and partly in section, showing vcarriage retarding or braking mechanism, the section be- .ing taken on the line 6 6 of Figure 7;

Figure 7 is a fragmentary view, partly in top plan and partly in section, the section being taken on the line l--l of Figure 6;

Figure 8 is a vertical section taken on the line 8-8 of Figure 7 .and drawn on an enlarged scale;

Figure 9 is a section, taken on the line 9-9 of Figure 1, showing a driven friction wheel'or drum and associated spring', other parts being omitted;

Figure 10 is a perspective view of a control switch;

Figurell is a section taken on the line II-II of Figure 10;- l

Figure 12 is a perspective view, on an enlarged scale, of certain operating .parts comprising the carriage return control mechanism illustrated in .Figures 4 and V5, the housing and supporting parts being omitted;

A roller 24 on the'bell crank lever through an oblong slot-25 formed in a bell crank lever 26 pivoted as at 21' on the shelf I8, the arrangement being such that rocking of the bell crank lever 28 will, through the roller and slot I9 extends up connection 24-25, effect rocking of the bell crank Figure 13 is a section 4on the line I3-,I3 of y Figure 12;

Figure 14 is a perspective view drawn on an enlarged scale showing a brake arm bell crank and associated parts;

Figure 15 is a fragmentary perspective view of a part of a margin stop;

Figure 16 is a perspective view of a clip slide wear-resisting margin stop attachment; and

Figure 17 is a perspective view of a margin stop body with the clip slide attachment aillxed and return movements. The carriage is provided with the usual top rail 3 supported on the bottom rail I by means of ball bearings 8, and is equipped with rollers 5 adapted to roll upon and support the carriage on the rear rail 2. A platen C, rotatably `mounted on the carriage in a, known manner, is equipped with a ratchet wheel arranged to cooperate with a pawl 1 carried by a rock ,arm 8 adapted to be rocked in the usual manner for eecting line spacing movements of the platen. A margin stop bar 3, supported at the rear of the carriage, mounts the usual margin stops, one (I8) of which is shown as being of a known construction which includes an abutment screw II adapted to engage a center stop I2 and buffer I3 thereon when -the carriage reaches the end of its return movement. An escapement rack It, supported on the carriage, is in mesh with an escapement pinion I5, rotation oi which is controlled by suitable escapement mechanism, not shown. Keys I8 are arranged to effect operation of the usual and known kinds of typewriter mechanism which includes tabulating mechanism, not shown, but parts of which are housed within a tabular finger,` cover I1. The parts thus far described are of known form and some other parts shown in' the drawings, but not specifically referred to by lreference characters herein, will readily be recognized 'as constituting theusual typewriter equipment and construction.

Figures l and 3 illustrate mechanism for -eflfecting line spacing movements of the platen aulever I8, thrusting of the link 2l, and rocking of the line spacing arm 8 and p'awl 1. The short arm 28 of the bell crank lever 28 is bent so -as to pass downwardly through a lslot 28l in the' shelf I8 below which it is connected to one end of a, spring 29, the other end of which is connected to a post 38 mounted on the under side of the shelf I8. The long arm 3| ofl the bell crank lever 28 isconnected at 32 -to a draw band v33 adapted to be pulled or drawn to the right. as viewed in Figure 1, after the completion of the typing of' aline for effecting, first, the line spacing movement of the platen and then the pulling of the carriage to the right or in the return direction. A stop armv 34 is adjustably secured to the shelf by meansof a screw 35 and is provided with an ear 36 adapted to be engaged by a pin 31 on the arm 3| of the bell crank lever 28when the lever is swung in a clockwise direction as viewed in Figure 1. To provide for manual line spacing of the platen C when desired,

a line spacing handle 38 is pivoted on the carprovided with a. pin 48 riage as at 39 and is which extends into'a slot 4I in a link 42 plvotally connected to the line space rock arm 28 at 23.

In operation, when a typed line has been completed, mechanism for drawing. the band 33 to the right isset in operation, in a manner to` be described, so as to pull the band 33 and rock the bell crank lever 26 clockwise until the pin 31 engages the ear 38 on the stop arm 34. During this rocking of the bell crank lever 28, the bell crank lever I9 will be rocked counterclockwise,thereby-rocking the arm 8 which, through the pawl 1 engaging the ratchet wheel 8, imparts rotary line spacing movement to the platen. It will be observed that thepower operated actuation of the-line spacing mechanism will not move'the line space handle 38, the handle being permitted to remain at rest by the pin and slot lost motion connection 404I.. When the rockingof the bell crank lever 26 is arrested by engagement of the pin v31 with the stop arm ear' `38, further movement ofthe band 33 willdraw the carriage to the right.

tomatically just prior to the commencement of line spacing mechanism shown herein includes a bracket or shelf I8 secured to the typewriter carriage and serving to mount a bell crank lever I8 pivotally mountedon the shelf as at'28. A .link 2|, pivotally connected to the bell crank lever I 8 as at 22,'extends forwardly for pivotal connection at 23 to the line spacing rock arm 8.

. as being 'formed in two parts,I the first part i The present invention relates more4 particularly to improved power operated mechanism for drawing or pulling the band 33 vand for con-V trolling the driving and retarding of the carriage as will'now be described. A mechanism housing L generally designated 43Ais provided with a mounting plate 44 which is supported on the frame A of the machine by three studs or posts 45. 'Ihe plate 44 is formed with a flange. which sup-,I ports a friction drum and winding reel housing 41 comprisingv a plate 41 and a cover 41. A pintle 48 is secured to the flange 48 and plate 41 by means of a nut 49 and is formed with a reduced outer'end 58 to' which the cover 41.b is secured by a screw 50. A self-ailing bearing sleeve 5I, surrounding the reduced pintle portion 58, mounts a winding reel 52 and a driven friction wheel or drum 53 which is secured to the winding reel 52 by rivets 54. The drum 53 -is shown comprising a disc 55 having a peripheral flange 58 and having eight fingers 51 struck down from the web of the disc, each fingerbeing vformed` aaaases 82 which clears anvenlar'ged part 83' of the pintle.

free from contact therewith so that the entire assembly of the winding reel 52 and friction drum 53 is journaled on the self-oiling bearing 5|.

The draw band 33 extends from the bell crank 28 over a guide pulley 84 journaled on `a bracket 85 mounted on the tabular finger cover I1 and is wound onv the reel 52, being secured thereto by a screw 88. A clock type spring 81, anchored as at 88 to one of the ngers 51, is secured to the pintle as at 89, the arrangement being such that the spring constantly tends to rotate the drum 53\ and reel 52 in a direction to maintain the draw band 33 taut irrespective of the position of the carriage on the frame.

Referring now to the mechanismV for rotating the friction wheel or drum 53 and the reel 52, the mechanism housing plate 44 is provided with two ea'rs or standards 10 on which va cradle 1| is rockably mounted by lugs 12 supported by pivot screws 13. A n electric motor 14, secured to the cradle 1| by mounting screws 15, has a shaft 18 provided with a driving friction wheel 11 much smaller than the driven friction wheel or 'drum 53 and preferably b eing formed of suitable resilient material, such as rubber.. The cradle 1| is provided with an extension or ear 18 to which is connected one end of a coil spring 19 anchored,

at its outer end on a post 80 fixed to the mounting plate 44. Normally, the spring 19 holds the ear 18 up and thus holds the cradle 1| and the motor 14 in a position -such that the friction wheel 11 is out of engagementwith the friction wheel 53.

` Control mechanism is provided for rocking the cradle and the motor 14 from non-drive eiiecting position to drive effecting position in which the driving friction wheel v11 frictionally engages the driven wheel 53, the control mechanism also preferably being adapted to start the motor just after engagement ofthe

wheels

11 and 53 vhasbeen eected. In the control mechanism shown, an arm 8| underlying the cradle 1| is formed with an ear 92 which entends up into an opening 83 in the cradle 1| to form a pivotal connectionl anism to be described for rocking the cradle and motor to drive effecting position, the arm 8| with its extension 81 therefore constituting a master control member;`

As previously stated, the cradle 1| and motor normally are held by the spring 19 in non-drive eie'cting positions. For pressing down on the extension 81 of the arm 8| to move the cradle and motor to drive effectingl positions, a bell crank lever 88 is pivotally mounted as. at 89 and is formed with an arm 90 having a swell portion 9| positioned above the extension 81 of the arm l 88 is pivoted as at 93 to the rear end of a thrust link 9,4, the front end of which is pivotally connected as atA 95 to a carriage return key 98 pivoted on the frame A by means of a screw 91.

' In operation, 'when the ykey v98 is depressed, the

link 94 is thrust rearwardly rocking the bell v crank lever 88 clockwise, as viewed in Figure,Y 5,

and causing the swell 9| to depress the extension 81. and rock the arm 8|, the cradle 1| and the motor clockwise, as viewed in Figures 3 and 4,'

thus bringing the driving friction wheel 11 into drive eecting engagement with the driven` friction wheel 53. Adjustable eccentrics 98 and 99 are positioned respectively above and below the free end of thearm 90 of the bell crank lever 88 for limiting the rocking movement of the lever 88. A wrap springl|00 `urges the bell crank 88 toits non-drive effecting position.,

It oftenwill be desirable for' the carriage to be returned. all of the way to the limit of its return movement upon a momentary depressing of the carriage return key 98 without its being necessary to hold the key depressed during the entire carriage return travel. For accomplishing this purpose a holding or latch element |0| is pivotally mounted as at |02 on a bracket |03 mounted for vertical adjustment on the plate 44 by means of screws |04 having threaded engagement with the plate and passing through slots |05 in the bracket. |03. The.latch is formed with a nose |08 which is adapted to be projected over the extension 81- of the arm 8| under ,the urge of a spring |01 secured at one end to the upper part of the latch and at its other end to an earl08 on the bracket |03. The latch |0| normally is free to be rocked by the spring |01 as soon as `the extension 81 of the arm 8| is moved below the level of the nose |08, at` which time the nose passes over the extension 81 and comes will be described later.

.Thus, in operation, when the extension 81 of the arm 8| has been pressed vdownwardly by depressing the carriage return key 98, the spring |01 will rock the latch clockwise, as viewed in Figures 3 and 4, into holding engagement withthe extension 81 so that after the carriage return key is released the drive friction wheel 11 will be maintained in drive eiecting engagement with the driven friction wheel 53. In some instances, however, as when tabulating operations are to be performed, it is desired to render the latch |0| ineffective. For this purpose selector means are provided for conditioning the control mechanis'm to eect sustainedcarriage return movement only during continued depression of the carriage return key98 or, alternatively, to condition the control mechanism for effecting sustained and complete carriage return movement following only momentary depressing of the carriage return key 98. In the form shown, the selector mechanism includes a bar formed` friction washer ||1a on the plate 44 and having The other arm 92 of the bell crank lever` a forwardly extending handle IIB conveniently disposed toward the front of the typewriter. The rear end of'the bar is ybent as shown in Figure l. to. form a :latch engaging portion Il!! adaptedto be projected into the path of the lower end of the latch when the bar is moved to the rear, as viewed' in Figure 1, .and` to the right, as viewed in Figure 5, by depression of the selector handle ||8, ,fthe larrangement being such that when the bar' is thus shifted, the latchengaging portion ||9 will preventmovement of the so relatively disposed with relation to the point of engagement of-the wheel 11 with the wheel 53 thata 'tangent T-T common to the two

wheels

11 and 53 at their point of engagement passes betweenA the axis of the motor pivots 13 and'the axis of 'rotation' of the friction wheel 53. Consequently, rotation of the driving friction l wheel 11 in the direction of the arrow a in Figures 3 and 4, when the wheel 11 is engaged with the wheel 53,' will tend to rock the motor clockwise, as viewed in Figures 3 and 4, so as to hold the wheel 11 in driving engagement with the wheel 53. This holding force, together with the .light pressure exerted by the spring 86 which provides a floating connectionbetween the motor and the arm 8|, assures the maintaining of y, proper pressure contact between the

wheels

11 and 53 without its being necessary to use a spring 86 capable of exerting the` entire force required to hold the two wheels in proper driving pressure contact. The use of a light spring 86, thus made possible, results in requiring a lighter key touch for setting the wheel 11 in'proper driving contact with the wheel 53 than would be required if the parts were not so relatively disposed'that the rotation of the driving wheel 11- I tends to make it hug or pull up vagainst the driven wheel 53.

Although the mechanism for line xspacing the platenand returning the carriage may be con- 'trolled entirely by the rocking'of the motor 14, it is desirable for'the motor to be stopped when the

friction wheels

11 and 53 lare not engaged for effecting carriage return travel. To this end,

"a switch |20 in circuit with the motor is adapted t be operated automatically so as to start' the motor just after the driving wheel 11 has engaged the drivenwheel 53, and to stop. the motor just before the drivingwheel 1l becomes di's,

'-Normally, the arm |29 is spring-urged by its own resiliency to an elevated position with the contact point |30 thereon disengaged from the contact screw 33. For automatically closing the switch and the motor circuit when the motor is rocked to drive eifecting position, a plungeror push rod |35 'ofnon-conducting material is .mounted in a bushing |36 secured to-the top iliange- |33.of the switch body, the lower enlarged end |31 of the plunger being disposed above and in contact with the spring arm |29 and the upper end of the plunger being rounded and disposedunder and for engagement with the extension 81 of the master control member or arm 8|. The connecting member |21 is provided with` Abindingor attaching screws |21 and |21 for connecting the arm |29 and contact point |30 in the motor circuit and to a condenser, respectively. The connecting member |3| is provided with binding or attaching screws |3|a and |3|b for uconnecting the contact screw |33 in circuit with the motor and to a condenser, respectively. A cut-01T switch |38, likewise, may be. connected in circuit with the motor as may be a line resistor element |39 and a condenser and fuse, not shown. Y

In operation, and assuming the cut-off switch |38 to be closed, the control switch |20 normally would be open so that the motor will not run. When, however, the extension 81 of the master control arm 8| is moved downwardly in the manner already described it will depress the plunger |35 and move the spring arm |29 downwardly to close the contact point |30 upon the contact screw |33 after the driving-friction wheel 11 has been moved into drive effecting engagement with the driven friction wheel 53; When the exten-- sion 81 of the master control member 8| is al- I lowed to move upwardly, the plunger |35 and spring arm I 29 also will be permitted to move upwardly to open the switch |20 before the driving mounted at the left and rear of the typewriter.

emanan,

continuous escape of uid during ascent o! the piston by restricting the escape sufliciently to cause the building up of a cushioning fluid pres*- sure tending to yieldably resist rocking of the brake lever |49 and thereby retarding the carriage. Inasmuch as the margin stop I must engage the upper end |56 of the brake lever |49 at each return. movement of the carriage and will slide on the lever end |56, the parts will be Accordingly, the extreme upper end |56 of the'brake lever preferably is hardened and the margin stop I0 is provided with a protective slide or abutment generally designated |51. slide |51 and its mode of attachment to the margin stop is illustrated most clearly in Figures 15,

16 and 17. As shown in Figure 15, the margin stop, which may be of known construction, is

formed or provided with a lower plate portion |58 which is the portion which would engage the end |56 of the brake arm |49 were the margin stop not provided with a protective member. The

In order that the latch |0| of the power drive control mechanism will be disengaged from the master vcontrol member 8| to effect stopping of the carriage drive in response to the carriages reaching the end of its return travel, means are provided for moving the thrust link |09 in response to rocking of the brake lever |49. A screw |63, connected to the link |09, is mounted to fil element' |69 is sumciently stiff to resist closing during relativelyslow raising of the piston |46, such as4 would take place during a gradual manually effected return movement of the carriage.y

In order to raise the flap valve |69 just prior to the carriages reaching the extreme end of its return travel, a pin |1|, with its head disposedbelow the flap valve |69, extends down through The construction of the the piston web in position to be engaged by an abutment or ear |12 carried by the extension |5| ofthe lever |49. Preferably; the abutment or ear |12 is formed with a slot |13 receiving a pin |14 secured to the extension |5| and a screw |15 having threaded connection with the extension |5|, thearrangement being such that the abutment or ear |12 may be positioned adjustably so as to engage the pin |1| at diierent times with respect to position of the carriage on the frame. When the carriage reaches a predetermined position,'just prior to the engagement of the margin stop I0 with the center stop I2, the abutment |12-wi1l lift the pin |1| and open the fluid release valve .|69 so as to permit relatively rapid escape of fluid from within the cylinder |44 and thereby todiscontinue the retarding action. Releasing of the fiuid pressure takes place 'at about the same time that the brakev arm end |56 slides under the margin stop clip |51 and thus prevents straining or lifting of the margin stop rod` by the brake. arm. If desired, the flap valve |69 may normally be closed when the parts are at rest. but the described'arrang'ement, whereby the building up of some pressure in the cylinder is required to closethe flap valve, has the advanslide in a slot |64 in the plate |40 thereby supmeans of a screw |66L` The arrangement is such that when the bell crank brake lever |49 is rocked during return movement of the carriage it will engage the bushing |65 to shift the thrust link |09 (to theleft .as viewed in Figure 3) to rock the latch |0| and disengage the latch nose |96l from the master control member 8|. A U-shaped extension |61 at the top of the plate |40 acts as a guide for the brake' lever |49 at the end of carriage return movement, and a stop pin |618 limits rocking of the lever |49 by the spring |41.

In accordance with an important feature of the invention, the dash pot is provided with means for releasing pressure built up in the cylinder |44 just prior to engagement of the margin stop I0 with the center stop |2 so Aas to discontinue the retarding action of the dash potl and assure movenent of the carriage completely' to the end of its return travel. In the form shown, the piston |46 is provided with a fluid release valve port or -opening-|68 and with a cooperating ap valve element |69 secured to the top of the piston by a screw |10. The flap valve' tage of offering less resistance to slow manual movement of the carriage as sometimes is necessary when it is desired to position the carriage at some intermediate point on the frame.

In some instances it maybe desirable to disable the retarding mechanism entirely and, for this purpose, a disabling lever |16 pivotally mountedas at |11.on the plate |40 is provided with a resilient orleaf spring arm |18 secured to the lever by screws |19 and with a handle.|80 which extends beyond the typewriter frame A so as to be readily accessible to the operator.

Normally, the disabling lever |16 is in the position indicated infull lines in Figure 3, wherein it will have no effect upon the rocking of the bell crank lever |49. When it is desired to disable the retarding mechanism the disabling lever |16 is rocked to the position shown in-Figure 6, wherein the upper end of the spring arm |18 is positioned 'to be disposed under an ear |8| on the arm |50 of the brakelev'er |49 so as to hold the brake lever in its extreme rocked position.

Consequently, if the disabling lever. should be moved to the operative position shown in Figure l 6 while the bell crank |49 is in the position shown in full lines in Figure 3 with the piston |46 in its lower position, subsequent rocking of the bell crank lever |49 (counterclockwise'as viewed in Figure 3) will cause the ear |8| to engage l'the inclined face of the spring arm |16, as illustrated in dotted lines in Figure 8, so as to cam the latter away from the ear |8| and permit the ear. to move up over the spring arm |18 after which the latter will snap in under the ear |8|, as shown in full lines in Figure 8, thereby' coming to a position in which it will hold the brake lever |49 the friction wheel 11 has .being subjected to any retarding action.

position and will open the switch |20.

Operation v If it is desired that the drive and control and retarding mechanisms be conditioned to effect sustained carriage return movement upon the momentary depressing of the -carriage return key 86 without its being necessary to hold the key depressed, the selector. device ||6 will be moved' to the full line position, shown in Figure 5, so as to withdraw the latch engaging portion I|8 of the bar i|| from the path of the latch l0 I. The disabling leverl16 will be moved to the position slown-in full lines in Figure 3 and the cut-on switch |88 will be closed. When the typing of a line has been completed, the carriage-return key 86 will be depressed momentarily vseas to cause the swell porti'on 8| on the arm 80 of the lever 88 4 to press downwardly on the extension 81 of the master controlmember 8|, thereby. rocking the motor 14 about its pilvots 13 (clockwise as viewed in Figures 3 and 4) bringing the yfriction wheel 11 into engagement 'with the .friction wheel 53,

pressing downwardly, on the plunger |35 to close the circuit-through the switch |20, and effecting movement'of the latch nose |06 over the prov,iection 81 on the control arm 8|. ',The mechanism'is so timed that the-motor will start after been placed in operative engagement with the friction wheel 58. Driving of the wheel 58 and the reel 52 will wind up the draw band 88 which ilrstV will rock the lever 26 to effect line spacing of the platen in the manner previously described. When the lever 26 is stopped by the stop arm' 84 movement of the band 33 will drive the carriage in the return di.- rection. When the carriage reaches a `predetermined position` during its return travel, the margin stop I with' the protective slide |51 will engage the upper end |58 of the bell crank -|48 so as to rock the latter in response to further carriage return movement, thereby moving the piston |46 upwardly and closing the flap valve |60. The carriage will then continue to move .against the resistance of the fluid cushion in the cylinder |44. When the carriage reaches a predetermined position Just prior to its arriving' at the extreme end of its return travel, corresponding to a distance of about onefourth of an inch between the margin stop abutment screw Vand the .center stop I2, the ear |12 on thekbell crank lever |48 will engage the pin I1| and raise the flap valve |68 .so as to eilect a quick release ofiluid from the cylinder |44, thus allowing the carriage to m'ove the remaining distance without When center stop. The carriage will reboundsliglitly and come to rest with the margin' stop screw in the position indicated in dotted Alines in Fig- If it is desired that the drivingand control mechanism .be conditioned to eil'ect sustained carriage return movement only while the carriage return key 86 is held depressed, for example, to save time in performing tabulating operations, theselector device I I8 is rocked tothe position shown in dotted lines in Figure so as to project the latch-engaging portion II8 of the bar |II.into the path of the latch |0|. To eiect l a -return movement oithe carriage the key 86 will'be depressed and it will have to be held de'- pressed during the entire time it is desired that the carriage travel in the return direction.

Otherwise, the operation will-be the same as described above.

If it is desired that the retarding mechanism be disabled or rendered inenective, the disabling lever |16 is moved to the position shown in Figure 6, so as to plac'e the spring arm |18 under the ear |8I', thereby preventing rocking of the bell crank lever |48 and downward movement of the piston |46.

The foregoing recapitulation of the operation has reference to the normal functions performed Vunder most conditions of use. However, in some instances, the left'margin stop I0 may be 'moved to the right of the center stop (as viewed in Fig.- ure .1) by pressing the usual margin release key (not shown) to shift the center stop I2'to the rear of the path of the marginstop, after which' the. carriage may be -movedto the right in the return direction either .manually or by means. of

,the carriage return mechanism disclosed herein. Also, .theleft margin stop I 0 may b e moved to the right past the center stop 2 without moving the carriage by being slid along the4 rack 8 either' manually or by stop-positioning means such as is shown in the copending application of Henry J; H'art, Serial No. 232,869, led October 1, 1938,

. now Patent 2,208,367. If the left margin stop is Amoved tothe right of the center stop I2 and thus beyond its normal position'of engagement. with the brake arm |55, the end |56 of the brake arm will slip from under the slide I 51, and the bell crank |48 will be' returned to its inoperative position shown in full lines in Figure 3. If writing is then resumed, the left margin stop i0 will approach the end |56 of the brake arm |55 from theright as viewed in Figure 1- and from the left as viewed in Figure 3, and eventually a beveled edge |86. on thesslide' 51 stop will engage a rounded edge |81 on the end I 56 of the arm |55, and will cam the arm end mit the margin stop |0 and appended slide |51 to proceed to the left as viewed in Figure 3 until the arm end |56 clears the ear |60 on the slide |51, after which the arm end I 56 will snap fori ward again to its normal position in the'path of the slide ear 60.

- In order to`permit this rearward movement of the bell crank lever |48 engages the sleeve |65 on the arm end 56, the arm |55 is yieldable. The U-sl'iaped extension or guide |61 previouslyY re ferred to serves to steady or support the yield'- able arm |55 against lateraly deflection during -normal operations after the arm end |56 ceases to have contact under pressure with the margin stop slide ear |60,

carried by the-margin If the margin release key (not shown) is held effecting position dependent on said manually operable device, said disabling means including a i settable selector adapted when moved to a set position to maintain said'disabling means effective for preventing operation of said holding element,

- and means for releasably holding said selector in However, before the carriage reaches its extreme 7 position to be stopped by engagement of the end plate |88 with the screw |89, the end plate |88 will engage a portion |9| of the brake arm |55 as shown in Figure 14, thereby rocking the arm counter-clockwise as viewed in Figures 3 and 14, thus retarding the carriage, and finally shifting the link |09 to discontinue the carriage return drive in the manner already described.

It will be apparent that mechanism embodying the novel features hereinbefore described pcssesses the advantage of being free fromgears, clutches, and other driving parts requiring accurate machining, tting, and assembling. The absence of such parts also makes for smooth and quiet operation, and the number of parts, which is very small as compared to prior carriage return mechanisms, renders the construction economical to manufacture and service. The small number of wearing parts also requires very little lubrication. The parts of the carriage drive mechanism arereadily accessible and the mechanism is adapted to be applied to existing typewriters in such a manner as not to interfere with the servicing of the usual or standard typewriter parts.

The mechanism disclosed herein embodies the invention in a practical and the at present preferred form, but it will be understood that various changes may be made without` departing from the invention as defined in the claims,

I claim:

1. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and ,return movements; power-operated means for driving the carriage in return movement direction; and mechanism for controlling said poweroperated means comprising a manually-operable key, connections between and associated with said key and said power-operated means for effecting operation of lsaid power-operated means A.and sustained carriage return drive during continued manual depression of said key, selectively operable holding means for maintaining said power-operated means operative to effect sustained carriage return drive following momentary depression of said key, a selector movable to two set positions for rendering said holding means respectively operable or inoperable, and means for mounting said selector for releasably maintaining it in either of its set positions.

2. In a typewritngmachine, a frame; acarriage mounted thereon for letter-spacing and return movements; power-operated means for driving the carriage in return movement direction; 1

and mechanism for controlling said power-operated means comprising a master control member, a manually operable device for moving said master control member to drive-effecting position, a holding element for maintaining said master control member in drive-effecting position, disabling means operable at will for preventing operation of the holding element-to thereby make holding of the master control member in drivesaid set position.

3. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; power-operated means for driving the carriage in return movement direction; mechanism for controlling said power-operated l.means comprising a manually operable device, said mechanismbeing adapted to be conditioned for effecting sustained carriage drive only during continued manual holding of said device or to be conditioned 'for effecting sustained carriage return drive following momentary actuation'of the manually operable device, means including a selector movable to two set positions selectively to condition the control mechanism foi` effecting sustained carriage return drive only during continued manual holding of s aid device or to condition the control mechanism for effecting sustained carriagereturn drive following momentary actuation of the manually operable device, and means for releasably maintaining said selector in either of its two set positions, depending upon which it has been moved to.

4. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; power-operated means for driv-l ing the carriage in return movement direction;

and mechanism for controlling said p'ower-op- V erated means vcomprising a master control member, a manually operable device for moving said master control member to drive-effecting position,

la holding element for maintaining said master control member in vdrive-effecting position, 'a selector movable to two set positions selectively to disable the'holding element and thereby to condition the control mechanism for effecting sustained carriage return drive only during continued Lmanual holding of said device or to enable said holding element and thereby condition the control mechanism for effecting sustained carriage return drivey following momentary actuation of the manually operable device, 'and means for releasably maintaining said selector lin either kof its set positions, depending upon which it has been moved to.

5. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacingand return movements; .power-operated means for driving the carriage in return movement direction; and mechanism for controlling said power-operated means comprising a master control member, a manually operable device for moving said master control member to drive-effecting position, a latch movable to inactive position and to active position in which it holds the master control member in drive-effecting position, and selectormeansincluding a part normally in a set position in which it permits unobstructed operation of the latch to condition the mechanism for eifectingfsustained carriagereturn drive following momentary actuation of the manually operable device, said partbeing movable to a set position in which it prevents operative engagement of the latch with the master control member to thereby condition the mechanism for effecting sustained carriage return drive only during con-` tinued manual holding of said device, and means for releasably maintaining said part in either of I mechanism for controlling of carriage return movement,

has

able to drive-.effecting and non-drive-eilecting.

positions, a manually operable device for moving said member to drive-effecting position, a latch for releasably holding said member in drive-eiecting position, means for retarding the carriage during the last part of its return movement and for releasing said latch at the end o f carriage return. movement, and disabling means operable selectively to disable only the latch or to disable both the latch and the retarding means.

7. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and .return movements; power-operated means for driving the carriage in return direction; and said power-operated means comprising a master ,control member movable to drive-eiecting and non-drive-eiectingpositions, a manually operable device for moving said member to drive-effecting position,

a latch for releasably" holding said member in drive-effecting position, means for retarding the carriage during the last part of its return movement and for releasing said latch at the end said latch without disabling said retarding means, and means for disabling said retarding means and locking said' latch in released position.

. 8. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; power-operated means for driving the carriage in return direction; and mechanism for V'controlling said power-operated means comprising a master control member movable to drive-effecting and non-drive-effect ing positions, a manually operable device for moving said member to driveeffecting position, a latch Vfor releasably holding said member in means for' disablingA `pivotedon said frame,

dash pot element, anabutment on said carriage engageable with said b ellcrank lever for rocking the latter to move said dash pot elementagainst the uid cushion when the carriage 'approaches the end of its return l link connected to said latchand having. a part mounted for adjustame positioning pn-said 1mi; and being engageable vby r said bell crank lever when the carriage is substantially at the extreme end of its return travel for shifting said link and thereby releasing said latch.

'10; In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; power-operated means for driving the `carriage in return movement direction; and mechanism for controlling said poweroperated means including a margin stop on said carriage, a member movably mounted on .said frame and being disposed in the path of the mare gin stop during carriage return movement,and

- a hardened metallic protective slide attachedgto said margin stop for engaging said member' to effect movement thereof and control of. said power-operated means, said 'protecti ve `slideconfi-g prising a lower plate portion extending under, the margin stop, ears extending upwardly from said plate portion and adjacent the ends of said margin stop, and a return-bent Vextensionof; said plate portion which overlies the margin stop. 1l, In a typewriting machine, a frame; acarriage mounted thereon for letter-spacing and return movements; power-operated means for driving the carriage in retum'movement direction; and mechanism for. controlling said poweroperated means including a bell crank lever a part on the carriage l engageable with said lever for rocking it, and

drive-effecting position, a dash pot device including an element movable against a iluid cushion, a bell crank lever pivoted on said frame and being 'operatively connected to said movable dash pot-element, an abutment on said carriage engageable with said bell crank lever for rocking the latter to move said dash pot element against the iluid cushion when the carriage ap'- pi'oaches-the end of its return movement, and a thrust link connected to said latch and having a part engageable by said bell cranklever when the carriage is substantially at 'the extreme end of .its return travel for shifting said link and thereby :releasing sai-d latch.

9. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; power-.operated means for driving the carriage in return direction; and

mechanism for controlling said power-operated means comprising a master control member movablev to drive-effecting and non-drive-eil'ecting positions, a manually operable device for moving said member to drive-effecting position, a

t latch forI releasably holding said member in drive-effecting position, a dash pot device including an element movable against a fluid of its travel including a cylinder element, apiston` cushion, a bell crank lever Apivoted on said frame and being operatively connected to said movable operated means a disabling member mounted for movement on said frame and having a spring leaf latch portion adapted when in operative position to extend under a part of said bell crank lever for maintaining said bell crank in which' it will not be operatively engaged by said carriage part, said and said `latch portion being inclined withrespec'.I to each other whereby said bell crank lever part may be moved to a position to be held by said latch portion after the latter has been moved "to operative positicn.

12. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; power-operated means for driving the carriage in return movement direction; andmechanism for controlling saidpowerincluding a bell crank lever pivoted on said frame, a part on the carriage engageable with said lever for rocking it, an earl on said lever, and a disablingv lever pivotedon` 13. In a typewriting element, and means positively lever in a position bell c'rank lever; part' said 'ear may `be ,movedto a position to be held by said latch portiomafter the latter has been moved to operative` 'positio n machine, a frame; a .carriage mounted thereon. for letter-,spacing and, return travel; anddash pot mechanism for cushioning the stopping of the carriage at one end operated -in re. sponse to carriage movement for relieving pres- 'sure in the cylinder when the carriage reaches a predeterminedposition just prior to its reachelement, one of said elements being mounted on the frame, actuating means connected to the other of said elements and being adapted to be operated by carriage movement as the carriage approaches said end of its travel to eiect fluidcushioned movement of the piston relatively into the cylinder and retarding of the carriage, a i'luid release* valve associated with one of said dash pot elements, and'means responsive tc arrival of the carriage at a predetermined position just prior to its reaching said end of its travel for opening said release valve.

15. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return travel; and dash pot mechanism for cushioning the stopping of the carriage at o ne vend of its travel including a cylinder element, a piston elemen't, one of said elements being mounted on thev frame, actuating means connected to the other of said elements and being adapted to be operated by'carriage movement as the carriage approaches said end of its travel to eiect fluidcushioned movement of the piston relatively into the cylinder and retarding of the carriage, a uid escape valve associated with one of said dash pot elements for permitting steady restricted escape of uid from the cylinder during relative movement of the piston therein, a uid release 'valve associated with one of said dash pot elements, and means responsive to arrival of the vcarriage at a predetermined position just prior to its reaching said end of its travel for opening said release valve.

16. In a typewritingmachine, a frame; a carriage mounted thereon for letter-spacing and return travel; and dash pot mechanism for cushioning the .stopping of the carriage at one end of its travel including a cylinder element, a piston element, one of said elements .being mounted on .the frame, actuating means connected to the other of said elements and being adapted to be operated by carriage movement las the carriage f ,approaches said end of its travel to effect uid- 'cushioned movement of the piston relatively into the cylinder and retarding of the-carriage, a I

constantly open uid escape valve associated with one of said dash pot elements for permitting steady restricted escape of fluid from the cylinder during relative movement of the piston therein, and a uid release valve associated with one of said dashpot elements and being normally open to permit relatively unrestricted escape of iiuid from said cylinder, said 'release valve being adaptedv to close in response to pressure built up in the cylinder during only rapid movement 'of the piston relatively into the cylinder.

17. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return travel; and dash pot mechanism for cushioning the stopping of the carriage at one end of its travel including a cylinder element, a piston element, one of said elements being mounted on the frame, actuating means connected to the operated by carriage movement as the carriage 'said dash pot elements and being normally open l to permit relatively unrestricted escape of fluid from said cylinder, -said release valve being adapted to close in response to pressure built up in the lcylinder -during only rapid movement of the piston relatively into the cylinder, and means responsive to arrival of the carriage at a predetermined position just prior to `its reaching said end of its travel for positively opening said release valve irrespective of amount of pressure in the cylinder.

18. In a typewriting machine, a lframe; a carr'iage mounted thereon for letter-spacing and return travel; and dash pot mechanism for cu'shioning the stopping of the carriage at one end of its travel including a cylinder element, a piston element, one of said `elements being mounted on the frame, an abutment mounted on the carriage, a bell crank lever pivoted on the frame and being operatively connected to the other of said dash pot elements, `said lever being adapted to be engaged and rocked by said abutment to eiect `huid-cushioned movement of the piston relatively into the cylinder and retarding of the carriagewhen the carriage approaches said end of its travel, a iiuid release valve associated with one of said dash pot elements, and means including a part on said bell crank lever for opening said valve when the carriage has arrived at a predetermined position'just prior to its reach- 4 ing said end of its travel.

19. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return travel; power-operated means for moving the carriage in return direction; a stop on said frame; a stop on said carriage engageable with,

said frame stop for limiting return movement of said carriage; and carriage-retarding mechanism including-a cylinder mounted on said frame, a piston reciprocable in said cylinder, an actuating member connected to said piston and being engageable by a part on the carriage when the latter approaches the end of its return travel for moving the piston into the cylinder, ,movement of the actuating member and travel of the carriage being resisted by building up of pressure in the cylinder, a release valve carried by said piston, and means engageable and movable by said actuating member just prior to engagement of said carriage-mounted stop with said framemounted stop for opening said release valve.

. j 2,01 In a typewriting machine, a frame; a car- -riage mounted thereon for letter-spacing and return travel; power-operated means formoving the. carriage in return direction; a stop on said frame; a stop on said carriage engageable with said frame stop for limiting return movement of said carriage; and carriage-retarding mechanism other of said elements and being adapted to be n approaches said end of its travel to eect fluid.-

cushioned movement of the piston relatively into including a cylinder mounted on said frame, a

piston reciprocable in said cylinder, a bell crank lever pivoted'on said frame, means connecting the piston to one end of the bell crank lever,.the

'other end of said lever being engageable by said carriage-mounted stop as the carriage vapproaches the vend of its return travel for rocking. the bell crank lever and moving the piston into the cylin-l der, a constantly open fluid escape valvefor said cylinder, a iiuid release valve for said cylinder including aiiap valve element normally in open position hut adapted to be closed by predetermined pressure in the cylinder, and a pin engageable by said lever just prior to engagement of said carriage-mounted stop with said framemounted stop for positively opening said flap valve element.

21. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return travel; power-operated means for movingA der, a constantly open uid escape valve for said cylinder, a uid release valve for said' cylinder including a flap valve element normally in open position but adapted to be closed'by predetermined pressure in the cylinder, a pin foropening said fiap valve element, and a pin-operating part adjustably positioned o n said lever and engageable with said pin just prior to engagement of said carriage-mounted stop with said framemounted stop.

22. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; and means for driving the carriage to effect return movements comprising a friction drum, a driving connection between said drum and carriage, a motor pivoted to rock about an axis'parallel to the drum axis of rotation, said motor having a shaft with its axis parallel to said drum axis, a friction wheel on the motor shaft, and-means for rocking said motor to effect engagement and disengagement of said friction Wheel and friction drum, the motor pivot and the point of engagement of said friction wheel and said friction drum being so relatively disposed and the direction of rotation of said friction wheel being such as to cause the driving force exerted by the friction wheel to tend to rock the motor and hold the friction wheel in driving engagement with the friction drum.

23. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; and means for driving the carriage to effect return movements comprising a friction drum, a-driving connection between said drum and carriage, a motor pivoted to rock about an axis parallel to the drum axis of rotation, said motor having a shaft with its axis parallel to said drum axis, a friction wheel on the motor shaft, a spring yieldably urging said motor to rock to a position in which the friction wheel and drum are out of operative engagement, and means for rocking said motor against the urge of 'said spring to a position in which the friction wheel and drum are -in operative engagement,

the motor pivot and the point of engagement of said friction wheel and said friction drum' being so relatively disposed and the direction of rotation of said friction wheel being such as to cause the driving force exerted by the friction wheel to tend to rock the motor 4and hold the friction wheel in driving engagement with the friction drum.

24. In a. typewriting machine, a frame; a carriage mounted thereon for letter-spacing and reshaft, a spring yieldably urging said motor to rock turn movements; and means for driving the carriage to effect return movements comprising a friction drum, a driving connection between said drum and carriage, a motor pivoted to rock about an axis parallel to the drum axis of rotation, said motor having a shaft with its axis parallel to said drum axis, a friction`wheel on the motor to a position in which'the friction wheel and drum are out of operative engagement, means for rocking said motor against the urge of said 'spring to a position in which the friction wheel and drum are in operative engagement, the motor pivot and the point of engagement of said friction wheel and said friction drum being so relatively disposed and the direction of rotation of said frictionwheel being such as to cause the driving force exerted by the friction wheel to tend to rock the motor and hold the friction wheel in driving engagement with the friction drum, and' a latch for maintaining said motor in said last named position.

25. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacingand return movements; and means for driving the carriage to effect return movements comprising a shaft, a spring yieldably urging said motor to rock to a position in which the friction wheel and drum are out of operative engagement, and means for rocking said motor against the urge of said spring to a position in' which Athe friction wheel and drum are in operative engagement, the axes of said motor pivot, said motor shaft, and said drum being so disposed that a tangent common to said friction wheel and said drum at their :point of engagement passes between said motor pivot axis and said drum axis.

26. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; and means for driving the carriage to effect return movements comprising a driven wheel, a carriage-driving connection between said wheel and said carriage, a motor pivotally mounted for rocking movement and having a shaft, a driving wheel on said shaft, an arm movably connected to said motor at a first point and at a point spaced from said first point having a limited floating movement connection to said motor, and means for moving said arm to rock the motor to engage and disengage the driving and driven wheels.l

27. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; and means for driving the carriage to effect return movements comprising a driven wheel, a carriage-driving connection between said wheel and said carriage, a motor pivotally mounted for rocking movement and having a shaft, a driving wheel on said shaft, an arm pvotally connected to said motor at one point and at a point spaced from said pivotal connection point having a limited oating movement connection to said motor, and means for moving `said arm to rock the motor to engage and disengage the driving and driven wheels.

28. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; and means for driving the carriage to effect return movements comprising a driven wheel, va carriage-driving connection beaasaes tween said wheel and said Qarriage, a motor pivotally mounted for rocking movement and having a shaft, a driving wheel on said shaft, an arm movably connected to said motor at a rst point and at a point spaced from said first point having a limited floating movement connection to said motor, a spring for yieldably urging said motor to rock in a direction to eiect disengagement of said driving andy driven Wheels, and an operating member engageabie with said arm for rocking it and said motor in the opposite direction to effect engagement of said driving and. driven wheels.

29. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; and means for driving the' carriage to effect .return movements comprising a driven wheel, a carriage-driving connection netween said wheel and said carriage, a motor pivotally mounted for rocking movement and having a shaft, a driving wheel on said shaft, an arm pivotally connected at one of its ends to said motor, a spring anchor connected to said motor,

a spring interposed between saidanchor and an' intermediate portion of the arm,l and means for pressing the. opposite end of the arm to compress the spring and thereby rock said motor to effect engagement of said driving and driven wheels.

30. In a typewriting machine, a frame; a carriage mounted thereon for letter-spacing and return movements; pov1eroperated means for driving the carriage in return direction; and mechanism for controlling said powerd-operated means including a lever pivoteoi on said frame and adapted, when rocked, to stop the carriage return drive, a margin stop on said carriage normally engageable with said lever when the margin stop reaches a predetermined position during the return travel of said carriageA for so rocking said lever, and means whereby said margin stop can be moved in carriage return direction beyond its position of engagement with said lever, said lever being yieldable transversely to its plane vof rocking and said lever and said margin stop being cooperatively formed to, have camming engagement with each other for deilecting said lever laterally out of the path of said stop when said stop is moved in letter-spacing direc tion after having been moved in return direction beyond its normal position of engagement .with said lever. i

3l. In a typewriting machine, a frame; a carriage `mounted thereon for letter-spacing and return movements; power-operated means for driving the carriage inreturn direction; and mechanism for controlling said power-operated means including a. lever pivotedon said frame and adapted, when rocked, to stop the carriage return drive, a margin stop on said carriage normally engageable with said lever when the margin stop reaches a predetermined position during the return travel of said carriage for so rocking said lever, means whereby said vmargin stop can be moved in carriage return direction beyond its position of engagement with said lever, said lever being yieldable transversely to its plane of rocking and said lever and said margin stop being cooperatively formed to have camming engagement with each other for deecting said lever laterally out of the path of said stop when said stop is moved in letter-spacing direction after having been moved in return direction beyond its normal position of engagement' with said lever, and a guide on-said frame adapted to receive and support against lateral deflection `a portion of said yieldable lever when the latter has been engaged by said stop and rocked thereby to drivestopping position.

32. In a typewritingmachine, a frame; a carriage mounted thereon for letter-spacing and return movements; power-operated means for driving the carriage in return movement direc= tion; and mechanism for controlling said power operated means including a margin stop on said carriage, a member movably mounted on said frame and being disposed in the path of the margin stop during carriage return movement, and

a protective slide clip-attached to said margin' stop for engaging said member to eect Inovement thereof and control of said power-operated means, said protective slide comprising a plate portion adapted to -lie against a rsurface ofl the margin stop and a spring iinger exten from said plate portion and over an'opposed surface of the margin stop. Y