US2284017A - Typewriting machine - Google Patents

Description

May `26, 1942. H. l.. PITN'IAN TYPEwRTING MACHINE Filed April 19, 1939 3 Shets-Sheet 1 No, mm, mw mv. vh

mi E MS um INVENToR ANh w P L W EN..

ORNEY 3 Sheets-Sheet 2 INVENTOR HENRY L. P/7-'MAN BY a ATTORNEY May 26, 1942. H. l.. PITMAN TYPEWRITING MACHINE Filed April 19, 1939 May A26, 1942. H. 1.. PrrMAN TYPEWRI'IQING MACHINE Filed Arpril 19. 1939 3 Sheets-Sheet 5 LFLI INVENTOR HENRY L. P/rMA/v BY /G ATTO RNEY

Patented May 26, 1942 TYPEWRITING MACHINE Henry L. Pitman, Hartford, Conn., assignor to Underwood Elliott Fisher Company, New York, N. Y., a corporation of Delaware Application April 19, 1939, Serial No. 268,767

fol. 197-73) 17 Claims.

This inventionv relates to typewriting machines and more particularly to their case shifting mechanisms. A

An object of the invention is, generally, to provide improved means responsive to operation of the case shift key for effecting the case shifts.

The case shift may be transient as for merely typing the initial letter of a word in capital or upper case. The case shift may also be sustained, by bringing case-shift-lock mechanism into play, as for typing successive characters in upper case or capitals.

Another object of the invention is to enable the typist to control at will, conveniently and eX- peditiously, a transient case shift or a sustained case shift. To this end the invention relieves the typist ofv the necessity of operating or selecting secondary or alternative keys such as a caseshift-lock key and, as is necessary in certain prior machines, a case-shift-release key,

The determination of transient or sustained case shift may be accomplished, as will hereinafter appear, by a simple diiference in manipulations of one and the same case shift key. Thus, a depression and immediately following release of the case-shift key by the typists finger may determine a sustained case shift. The same key may be redepressed and immediately released for ending the sustained case shift and effecting return to lower case condition; A

For a. transient case shift the typist may operate this same shift key as is done ordinarily, that is, by depressing the case shift key preparatory to typing 4one upper case character and then releasing the key to effect return to lower case condition when said upper case character has been typed.

The invention employs a, power drive as distinguished from manual effort for moving the case shiftable part, which in the present instance is a case shiftable platen frame.

Another feature of the invention is in a correlation of the power drive with the before mentioned features of simple case shift key operaltion.

Still another object of the invention is to carry it out by simple, inexpensive and reliably operating mechanisms and, moreover, to make such mechanisms readily applicable to existing designs of typewriting machines.

A typewriter usually has two case shift keys on opposite sides of the keyboard so that either the left hand or right hand of the typist may effect the case shift. 'Ihe invention deals with having either one of such two keys operative as above described for determining tained case shift.

Theforegoing and other objects, features and a transient or susadvantages will be apparent from the followingV description of an illustrative operative embodiment of the invention.k Y

" gaging a roller 2| on the In the accompanying drawings:

Figure 1 is a cross sectional side view of a type, writing machine including mechanisms embodying the invention. Y

c Figure 2 is a perspectiverof the mechanisms embodying the invention, some of the parts being broken away and sectioned to bring out details clearly.

. Figure 3 is a` partly` sectioned side elevation showing the relative positions of the parts during a case shifting operation when the keyis held depressed.

Figure vi is a partly sectioned side elevation showing the relative positions of the parts consequent to operation and release of the key forA a sustained case shift,

The typing machinevframework I0 has front and rear rails I l, |2 for a typing carriage I3. Type bars I4 having lower and upper case type I5 are i actuatabl'elabout a fulcrum I6 to print tgainst a revoluble platen I'ljournaled in a frame I8. Said frame I8 is movable up and down in the typing carriage I3 for case shifting the platen relatively to the types I5. A shift rail 20, en-

platen frame I8, is

movable up and down in that it is part of "a frame rockable about pivots 22 in the framework and`comprisi`ng side plates 23 and a tie rod 24. Left hand .and'right hand case. shift keys' L and R, respectively, are on opposite sides of the keyboard. The key L is on a shift lever 25 that has a fulcrum rod 26 in the framework and that is normally upheld by a spring '2l against the top of its guide slot in a front comb plate 28. The shift lever 25 has a pin 3l to engage a cam arm 32 fixed to a transverse rock shaft 30. The key R is on a shaftlever 29 connected to said rock shaft 30 .whichv is journaled in the framework. An arm 33 fixed to said rock shaft 3B has a wrist pin 33a engaging a downwardly open slot 34 of the right shift lever 29. Said lever 29 alsohas a horizontal rearwardly open slot 35 for embracing the rock shaft 30. The relatively transverse slots 34, 35 provide for articulating `the right shift lever 29 to the pin 33a and the rock shaft 3B. The top of the slot 34 and the wrist pin 33a form a one-way connection by which depression of the right shift lever 29 from normal position rocks the shaft 30 counter-clockwise. A spring 36 43 to rock the latter counter-clockwise of Figure- 1 about a fulcrum support 44 on the framework. The coupling rack 43 is thus rocked for engaging its teeth with a continuously power driven toothed snatch roll 4E journaled vin the Vframework. The resulting stroke of the coupling rack or actuator 43 toward the rear of the machine rocks the shift rail frame 20, 23, -24` clockwise# of Figure 1 to lift the platen frame I8V to placeV the platen |1 in the dotted line or upper case position, Figure 1. The connections-for this purpose-include a lever 41 and a pull link48 pivotedthereto at 49.V vSaid pull link 48 has allost motionconnection, comprising-a stud 58 on the `plate 2.3

and a slot 5| in the link, to said-frame 20, -23, 24. Said lever 41 is fulcrumed-ontherod l28 in the framework and-has a pin-and-cam slot connection.54 to the coupling rack 43.

The coupling rack 43 is driven-in an extensive stroke by the snatchroll 45 sothat rotation of the latter through a comparatively large angle is ltaken to effect at moderate'speed the power case shift of the frame 20, 23, 24, and the platen frame |8. Said coupling rack 43, therefore,hasV

an extensive series of rack teeth 55 that supplement the leading teeth 56 which are embodied in a piece 51 pivoted tothe coupling rack at 58.

The feature of thus extensively driving acoupling rack such as 43 is disclosed in my copending applicationSerial No. 266,995 filed April' 10, 1939. Said co-pending application also dis- 2U, 23, 24. The counter-clockwise rocking of the shaft 39 effected by depressing either one of the case shift levers 25, 29, effects this forward movement of the link 14 for unlocking the shift rail frame. For adjustingV its length, the link f V65 thus cooperates with said latch arm 64 to detent said shift rail frame in upper case position, as in Figure '4, to maintain the platen I1 in upper case position.

At the Figure 4 forward position of the latch arm 64, its stud 18 is over a horizonta1 lift arm 84 thatV is madeV integral with the pendent link 12'and thus has become depressed by the forward displacement of the link 14. This forward displacement of thelink 14 is maintained as long as the typists finger keeps either one `of the shift levers, 25, 29, ydepressed Aand correspondcloses devices for keeping thecoupling'rack Vin engagement withthe snatchl rollduring'its extensive rearwarddrive. n'Said-devices include a n 59 on the coupling rack and a keeperplate 60 over'which the fin 59 rides inthe 'rearward snatch-roll-driven stroke ofthe coupling rack.-

Saidiin will havepassedbeyondsaid plate 60 by the ltime the coupling rack 43 'is 'deflected downwardly by engagement with an abutment 6| on `the framework to disconnect said vcoupling rack from the snatch roll at'the'end of the case shift. In the return stroke of the coupling rack 43, its fin-59 may pass under saidplate 60 which is supported upon a cross 'bar 62 of the` framework.

'For latching the Vshift rail frame 28,23, 24 in lower case position, a shoulderv 63 of a detentror latch arm 64 pivoted on the stud 58 of said frame engages an upstanding detent lip 650i a-bar 66 adjustably secured by screws 61 upon a platform 68 bentY laterally from a'bracket '69 which may. be supported by the framework.V An upturned ear10'of'said bar 66 has pivoted thereto at: 1| a pendent link 12 to which is pivoted at 13 a link 14 extending forwardly'toapivotal connection 15 withthe arm `33 that is fastpnthe rock shaft30.

A hexagonnuteccentrically and, therefore; adjustably secured tothe link 14 vby ra screw v16 constitutes a cam 11 that is normally immediately behind a companion stud or roller 18 on the latcharm 64 so that forward movement of said link f14 immediately raises said -latch arm B4 clear of thelip uilto-relea'se the shift rail frame ingly keeps the shaft 38 and its link-controlling arm 33 turned to the Figure Sposition.

. Whenrthe typists finger is taken off the depressed shift lever, the latter-returns to normal position by means of its spring and concomitantly the shaft 30, urged by a suitable spring 86 which may be applied to thelink 14 as in Figure 4, returns to normal position. The .rearward return of the link Y14 to normal position rocks the lift arm` 84 counter-clockwise to raise the latch arm 64 clear vof the lip 65. It results that the Shift frame 20, 23, 24 and the platen-frame AI8 return to lower casev position by gravity. Withr return ofthe shift'rail frame-to normal position, the coupling rack 43 also returns forwardly to nor-r mal position and concomitantly the lever 41and link 48 also return tonormal positions.

It will be apparent from the description thus far given that maintenance of the platen in upper case-position to which it has been power shifted rbymeans of the snatch roll 48 depends on keeping either Yshift lever, 25 or 29, depressed by the typists-finger. This mode of operation is usually employed when the shift vtoupper case is to be maintained only transiently as for writing only one character in upper case. f

S'For effecting a shift toupper case and sustainingsuch shift vas for writing successive characters in upper case, the typist merely depresses either shift lever, 25 or 29, momentarily as by giving it a simple downward tap. This tap, followed by immediate release and restoration of the operated shift lever, is nevertheless effective to rock the coupling rack 43 into engagement with thev snatch roll 46 so thatthe're results immediately a snatchV roll driven rearward stroke of said coupling rack and, correspondingly, the lever 41 is immediately turned counter-clockwise. The mechanism for sustaining the case shiftrisas follows. A

A cam plate 81 has guide slots 88, 89 for foreand-aft movements-on supports comprising a stu'd'or rod 90 on the framework and a stud 9| on the bracket 69. A pivot nut 92 eccentrically and therefore adjustably secured to said cam plate 81 by a screw carriesanfarm-93 against a rear end of which a finger 94 of-A the lever 41 bears so Athat the coin'iter-clockwisev rocking of said levermoves saidv cam plate 81 forwardly.

IAT latch lever 95 extends forwardly `from the fulcrum'rod 26-inthe framework and has a rollerorstud 96 which in the normal positions of the parts, Figures 1 and 2, occupiesa cam notch 91 of the cam plate 81. VSaid latch lever 95 has a pin 98 for engaging a latch hooked cam end 99 of the arm 33 of the rock shaft 30.

By a small initial portion of its snatch-rolldriven counter-clockwise movement, the` lever 41 moves the cam plate 81 correspondingly forward a small distance owing to the engagement of the lever finger 94 with the cam plate arm 93, the latter being stopped as at |I, Figure 3, against clockwise rotation on the cam plate 81. By this forward movement of the cam plate 81 to the Figure 3 position, its cam notch 91 engages the stud 96 of the latch lever 95 to depress the latter about the fulcrum rod 26. By such depression of the latch lever 95, its pin 98 engages and rocks the arm 33, and the shaft 30, counter-clockwise to draw the link 14 forwardly so that the cam nut 11 on said link lifts the latch arm 64 on the shift rail frame clear ofthe lip 65.- This enables the further Vcounter-clockwise movement of the lever 41, acting through the link 48, to rock the shift rail frame to ,upper case position. Until the latch arm 64 is lifted by the link cam 11 clear of the lip 65, the accompanying forward movement of the link 48 has no effect on the f shift rail frame owing to the 'lost motion con nection 50, 5| of said link to said frame.

If a sustained or prolonged case shift is desired, either one of the shift levers 25, 29 will have been given a downward tap and will have been immediately returned to normal position by its spring 21 or 36. In that event the latch hook- 99 of the arm 33 latches, under theA urge ofthe link spring 86,V over the pin 98 of the derail frame, and the platen frame I8, to return to normal or lowercase positions as by gravity..

Referring again now to a transient case shift,

for which the typists linger keeps either shift lever depressed, as in Figure 3, it is to be noted that this keeps the latch hook 99 suiiciently forward of the pin 96 on the latch lever 95 so that said hook cannot latch down said latch lever. Said latchlever 95 in that event is merely depressed idly by the forward movement of the cam plate 81 and becomes restored again when said cam plate 81 becomes restored consequently to its above described release from the linger 94 of the counter-clockwise driven lever 41. A horizontal slot I 04 in the cam plate 81 enables the latter to be moved forwardly relatively to the latch lever stud 96 at least up to the point at which said cam plate becomes released from the lever linger 94.

In the instant machine, the coupling rack 43 is so connected to the shift rail frame 20, 23, 24 that said rack after it has become disengaged from the snatch roll 46 by encounter with the abutment 6| remains rearwardly positioned as in Figure 4 as long as the shift rail frame is in upperA case position. lI'hus, depression of either shift lever 25, 29 to release said shift rail to return to` lower case does not entail an idle lstroke of the coupling rack 43 bythe snatch roll inasmuch as the frontend of said couplingy rack is out of operative range of the dog 4| on the arm of the rock shaft 30. Should either shift lever happen to be depressed so that the tab 42 of said dog 4| is in the path of the forward end of the' forpressed latch lever 95. This keeps the latch lever Y 95 down and in position to hold the arm 33,and

hence the link 14, sufficiently forward so that theV lift or releaser arm 84 -is sufficiently below the stud 18 of the shift rail frame latch arm 94 to permit said arm 94 to drop `finally into latching engagement with the lip 65, as in Figure 4, to sustain the completed case shift.

Before the snatch-roll-driven counter-clockwise stroke of the lever 41 is completed its finger 94, moving downwardly as well as forwardly, slips oif the arm 93 on the cam plate 81 wherefore the latter becomes restored rearwardly by a spring |02 to normal position, Figure 4, in which it is stopped by the stud 9|. This restoration of the mover or cam plate 81 brings its cam notch 91 back over the stud 99 of the depressed and latched lever 95 so that eventually the latter may rise to normal position again.

For terminating the sustained or latched upper case condition in which the parts are as in Figure 4, the typist merely depresses and immediately releases either one of the shift levers 25, 29. Such depression of either shift lever rocks the shaft 39 counter-clockwise sufficiently to move Figure 3.

the latch hook 99 oif the pin 98 of the latch lever turn clockwise to normal position under the pull of the spring 89 on thelink 14, said link concomitantly moving rearwardly to normal position. By such spring-urged rearward movement of the link 14,-the releaser arm 84, connected thereto, is lifted to raise the shift rail lframe latch arm 64 clear of the lip 65 to cause the shift wardly returningA coupling rack 43, the latter will merely turnv said dog clockwise about its pivot and upon restoration of the operated shift lever, `the dog, urged by a spring |05, will turn back to normal position against a stop |06 on the arm 39.

As the lever 41 rocks clockwise back to normal position, its finger 94 may idly rock the overlying arm 93 counter-clockwise onits pivot 92 until said arm 93, urged by a spring |01, drops topl'ace its rear end in front of said finger again as in In the returned or normal position, Figure 1,' of said lever 41, a shoulder |98 thereu of stops against an abutment |09 on the framework. A draw Aspring ||0 anchored to theframework tends to rock the coupling rack 43 clockwise about its fulcrum support 44 and thus tends'to keep said coupling rack normally disengaged from the snatch roll 46.V For its snatch roll driven stroke and return stroke, said coupling rack 43 is' slidably movable endwise on said fulcruming support 44. vThe framework may have stops for limiting the` down strokes of the shift levers 25, 29. The cam plate 81 may'have suitable lateral guides such as flanges or collars, not

shown, on its* supporting studs 90, 9|. The coupling rack 43 is laterally guidedfby a comb plate l2 on the framework and bythe llever 41 and by a bracket H3 that includes the fulcruming support 44, said bracket being on vthe framework. f

It will be seen now that case shifting is easily and expeditiously controllable yby the typist -through the medium of either one of the simple maintenance thereof,Y the. typist depresses either shift lever 25 o`r129 vandthe resulting upper case shift may be maintained only so long as the typists ngerkeeps the shift-lever depressed, say, while typing only one upper case character inasmuchas release of the shiftlever after typing said character' causes restorationrofthe parts to normal or lower case position..V For these several features of .case'shift control there are only two shift levers, right and left,1and either one of these may even be omitted except that it is desired to enable the typist to control the case shift by using. optionally 'either ther-ight hand or the left hand. Y

Variations may be resorted to within the 'scope of the invention and portions of the improvements may beusedwithout others. Y

What is claimed is: N v l Y l. In a typing machine, the combination` of a shiftable part, a shift key, power means,respon sive to movement of said key to 'operated position, to shift saidpart, said shifted part tending to return to normal position, a detent operative to maintain said partV in shifted position, a re-'" leasingr device tendingV to respond tolreturn of said key from said operated position to release said part from said detent, and means conditioned by the shifting of said part, depending on immediate return ofthe key from operated position, to disable said releasing device, whereby to determine sustained maintenance of said partin shifted position. Y

2.` In a typing machine, the combination of a shiftable part, a. shift key, power means, responsive tomovementof said keyk to operated posi-` the shift of saidpart to move said releaser tok retracted position and coincidentally interlock Y with and hold said releaser in retracted position independently of said key ifsaid key is immediately returned from operated position, said releaser being disengageable, bymeans of said connection, from said 'latch element by a second movement of said key to operatedV position so as Y to be: effective to .release said part in response to y normal position, a detent operative to maintain to immediate or delayed return of said key from tion, to shift said part, said shifted part tending to return to normal position, a detentop'erative to maintain said part in shifted position, a releasng'device tending to respond to return of VsaidV key from said operated position to frelease Y said part fromy said'detent, and means' and a holding `latch therefor conditioned concomitantly with the shifting -of said part, depending Y on immediate return Aofthe key fromoperated position, to disablesaid releasing device todeterminejsustained maintenance of said part inY Y of said key following said second, movement.

3.7In a typing machine, the combination of a shiftablepart, a shift key, power means, responsive to movement ofsaid key Vto, operated position, to shift said part,A said shifted-part tending said part in shifted position, and means acting differently under control of said key according its operated: position to` determine, respectively, non-release or release of said part from said detent through such return of said key. Y

` 6.r In a typing machine, the combination of a shift key, a part shiftable from a normal position by power in response to movement of said key to operated position, said part tending to returnlto normal position, a detent operative to maintain said 'part in shifted position, ,a spring-urged releaser held retracted by'said key when the latter is in 'operatedV position and moved by its spring to release said part from said detent when said key `is Yreturned vto'normal position, and means controllable differently by said key according to immediate ,or delayed return of said key from its operated position to block or permit; respectively,

the movement of theretracted releaser by its spring to release said-part from said detent.

7. In a typing-machine, the combination of a shift key, apart shiftableV from a normal position by power in response tomovement of said key vto operated position, said part tending to return to normal'position, a detent operative to maintainsaidlpart in shifted position, a releasing `device movable to ineective position by movement of 4said key to operated position and responsive to return of-said key from said operated position tow release said part from said detent, a'latch element movable to move said reto return to normal positioma detent operative to` maintain said lpartshifted position, a

spring-urged releaser having a xone-wayV operative connection to saidgkey. so asA toberetracted when the latterisinoperated position'and to be l spring moved to release said partffrom said detent When said key is returned-to lnormalposition, and alatch element operatively connectedA to said part andv releaserso astobemovedgwith the'shift of saidrvpart toA move `said releaser-,to retracted position and coincidentally interlock with and hold said releaser in retractedjpositrion Y diately returned from'op'erated position. s l s ris-In a typing machine, the combination'gofa independentlyofA saidk'ey if said key is immeleasing device toineifective position vand coincidentally "to interlock with and hold said releasing device invineiective. position if said key has beenreturnedto normal position immediatelyjafter-'its movement to operated position,and a movery actuatable for-so movingv said latch element, said mover having a disconnectible operative connection with said part so as to be actuated and then become automatically.disconnected from said-part duringtheshift of said part, said connectionV becoming effective again by the re-v turnof said part to normalposition, means being provided vtoV disengage said interlocked latch shiftableparta shift key, power means,` respons sive to movementof said key to Voperated position, toshift said part, saidshifted part tending to returnito normal positionha; detent operativeelementandreleasing device atwill, Y e

, 8. In aV typing machine, ythe combination of a shiftable part, a shiftkey, a power drivenactuat- Y ing means movable-in a power stroke by said driver at operation of said key tomove said part from a normalposition to a shifted position, said part tending to return to normal position, two detent members interlockable in two different relative positions to lock said part in normal position or shifted position, and means responsive to movement of said actuating means to disengage one detent member from the other preparatory to shifting said part, said actuating means having a lost motion operative connection to said part so that an initial portion of the power movement of said actuating means effects disengagement of said detent members before said part is moved by said actuating means, one of said detent members having an operative connection with said disengaging means and becoming free of said latter operative connection when said part becomes shifted so as to permit said detent members to cooperate to maintain said part in shifted position, means being provided to disengage said detent members for return of said part to normal position.

9. In a typing machine, the combination of a shiftable part, a shift key, a power driver, actuating means movable in a power stroke by said driver at operation of said key to move said part from a normal position to a shifted position, said part tending to return to normal position, two detent members interlockable in two different relative positions to lock said part in normal position or shifted position, and means responsive to movement of said actuating means to disengage one detent member from the other preparatory to shifting said part, said actuating means having a lost motion operative connection to said part so that an initial portion of the power movement of said actuating means effects disengagement of said detent members before said part is moved by said actuating means, one of said detent members having an operative connection with said disengaging means and becoming free of'said latter operative connection when said part becomes shifted so as to permit said detent members to cooperate to maintain said part in shifted position, and means operative under control of said key to disengage said detent members for return -of said part to normal position.

10. In a typing machine, the combination of a shiftable part, a shift key, a power operable driver, an actuator linked to said part and engageable with said driver by the movement of said key to operated position, said actuator becoming disengaged from said driver upon having effected a shift of said part from normal position, a detent operative to maintain said part in shifted position, a releaser held retracted by said key when the latter is in operated position, aV

spring urging. said releaser to disengage said shifted part from lsaid detent when said key is returned to normal position, a latch element operatively connected to said actuator and releaser so as to be moved to move said releaser to retracted position and coincidentally to interlock with and hold said releaser in retracted position independently of said key if said key is returned immediately to normal position, said key in its operated position holding said releaser from interlocking with said latch element, and means effecting return of said latch element to normal position if it does not interlock with said releaser.

11. In a typing machine, the combination of a shiftable part, a shift key, a power mechanism responsive to movement of said key to an operated position to shift said part from a normal position to a shifted position, and a lock mechanism controlled partly by said key and partly by'said power mechanism to effect and determine lsustained or transient maintenance of said part in shifted position in correspondence to immediate or delayed return of said key from its operated position.

12. In a typing machine, the combination of a shiftable part, a shift key, means, including a power-device, to shift said part by power from a normal position to a shifted position as a result of movement of said key to operated position, and a lock mechanism controlled partly by the shifting of said part by said means and partly by said key, to effect and determine sustained or transient maintenance of said part in shifted position in correspondence, respectively, to immediate or delayed return of said key from its operated position.

13. -In a typewriter; a shiftable part, a shift key, power mechanism to shift said part as a result of operation of said key, and shift-lock mechanism controlled partly by said key and partly in concomitance with the shift of said part by said power mechanism to determine maintenance of said part in shifted position or restoration of said part in accordance with immediate or delayed return of said key from an operated position. l

14. In a machine of the character described, the combination of a shiftable part, a shift key, power mechanism responsive to movement of said key to operated position to shift said part,

said part tending to return to normal position,

a detent to maintain said part in shifted position, a releaser tending in response to return of the key, torelease said part from said detent, a block, and a connection between said part and block whereby said block is interposed automatically, in accompaniment with the shifting movement of said part, to disable said releaser if the key has been immediately returned, said connection being constructed so as to be automatically disrupted when the block has been interposed so that the block is capable of returning and hence failing to disable said releaser if the return of the key is delayed. Y

15. In a case shift mechanism, the combination of a case-shiftable part, a case-shift key, power mechanism enabled by movement of said key to operated position to shift said part, said part tending to return to normal position, a detent to maintain said part in shifted position, a releaser tending in response to the return vof said key to release said part from said detent, and means controlled partly by the shifting movement of said part and partly by said key so as to disable said releaser or to permit said releaser to function, depending, respectively, on immediate or delayed return of said key.

16. In a case shift mechanism, the combination of a case-shiftable part, a case-shift key, power mechanism enabled by movement of said key to operated position to shift said part, said part tending to return to normal position, a detent to maintain said part in shifted position, a releaser tending in response to the return of said key to release said part from said detent, and means controlled partly by the shifting movement of said part and partly by said key so as to disable said releaser or to permit said releaser to function, depending, respectively, on immediate or delayed return of said key, provision being included for re-enabling said disabled releaser at will for consequent release of said shifted part from said detent.

detent said part in shifted position and to fcontrol said actuator to prevent its engagement by said key atv aV second operation of' said key, and means responsive to such second operation of said key to release said detent means.

HENRY L. PITMAN.

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