US3554348A

US3554348A - Key lock shift mechanism

Info

Publication number: US3554348A
Application number: US679753A
Authority: US
Inventors: John F Herrmann
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1967-11-01
Filing date: 1967-11-01
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12

Abstract

A key lock mechanism for a keyboard wherein a shift key lever and a key lock lever are mutually coupled by bridging members spanning intermediate key levers to latch and unlatch the shift key lever for deriving a compact, shallow keyboard.

Description

United States Patent [56] References Cited UNITED STATES PATENTS 3/1919 Trone...........................

[ 72] Inventor John F. Herrmann Pittst'ord, N.Y. [21 Appl. No. 679,753

197/9sux 197/98 1,423,443 7/ 1 922 Loomis. 2,168,441 8/1939 Doty........ 2,226,931 12/1940 Helmond. 2,229,400 1/1941 Vickery... 2,737,281 3/1956 Leonard 2,797,790 7/ 1 957 B1odgett.. 3,194,493 7/1965 Brewer.... 3,327,828 6/1967 Primary Examiner-Emest T. Wright, Jr.

[22] Filed Nov. 1,1967 [45] Patented Jan. 12, 1971 [7 3 Assignee The Singer Company a corporation of New Jersey [54] KEY LOCK Sm" MECHANSM Attorneys-George W. Killian, Patrick J. Schlesinger, Charles R. Lepchinsky and Jay M. Cantor 6 Claims, 3 Drawing Figs.

ABSTRACT: A key lock mechanism for a keyboard wherein a utually coupled by B4lj 5/22 shift key lever and a key lock lever are m [50] 197/7l,72, bridging members spanning intermediate key levers to latch and unlatch the shift key lever for deriving a compact, shallow keyboard.

PAT E NTED JAN 1 2191i INVENTOR.

JOHN F. HERRMANN BY ATTORNEY 1 KEY LOCK SHIFT MECHANISM The present invention relates to a keyboard mechanism and, more particularly, to a key lock mechanism for a key board mechanism.

Although the present invention is suited for more general applications, it is particularly adapted for use in a key lock shift mechanism for a typewriter keyboard. Shift and unshift functions in an electric keyboard are well known to those skilledin the art. In the past, complex electronic shift and shift lock devices have been used to lock the shift key when in a downor shifted position. Other attempts have used mechani- "cal means which includea lock mechanism mounted directly on the shift key lever. Although the prior art mechanisms have operated satisfactorily for the purpose intended, they have the disadvantage of being complex and costly.

7 Accordingly, it is anobject of the-present inventionto provide a new and improved key lock shift'mechanism which avoids one or more of the disadvantages and limitations of prior art mechanisms.

It is a further object of the invention to provide a novel key lock shift mechanism of compact and relatively simple construction and which exhibits smooth yet firm key manipulation together with quiet operation.

It is yet a further object of the invention to provide an improved keyboard mechanism possessing high versatility for numerous and diverse applications, combined with consistent dependability over prolonged periods of operation.

wherein said first shift key lever, when actuated, generates a code indicative of the fact that succeeding codes are to beinterpreted as representing upper caseletters and characters;

and wherein said second shift key lever, when actuated, generates a code indicative-of the fact that codes generated subsequent thereto are to be interpreted'ascodes representing lowercase letters and'characters. The named first shift key lever 'may appropriately be designated a shift key lever and the second shift key lever may appropriately be designated the unshift'key lever. The shift key lever and the unshift'key lever are coupled by a rocker arm lever'which is pivotal at a midt'point ora't somepoint along its length. The rocker arm lever coacts with the-shift and unshift'key lever-to maintain an out "ofphase relationship so that the operation of one of thekey levers produces one of the codes'and the-return-of that key lever-effects the operation 'of the other key lever through the rocker arm-to produce the other code.ln accordance with the irivention, the "key-lock shift mechanism includes a key lock leverwhich is disposed parallel to the shiftand' unshift'key 'levers in spaced relationship so that-other keylevers may be interposed therebetween and said key lock lever rests against a stop bar when the key levers are in the normally up position.

, Also included is a pawl rotatably mounted on the key lock leverandnormally urged in a clockwise direction towards'the stop bar'by a biasing spring. The pawl includes an arm positinned-in cooperative relationshipwith the'key lock lever-for urging-the key lock lever downwards when the pawl is rotated counterclockwise. The key lock lever includes a first tab bridging other key levers disposed between the shift key lever and the key lock lever. The first tab is coupled to the shift key lever so that the shift key mechanism is urged in a downward position whenever the shiftlockkey lever is urged in the same direction. The shift key lever includes a second *bridging memberwhich coacts with the pawl to' rotate it-in a'counterclockwise direction wheneverit is depressed in a downward position' to keep the pawl from engaging the stop barand converselywhenthe key lock lever is depressed within its limitof travel, the pawl is decoupledfrom theshift-keylever and rotated against the stop bar to retain the key lock lever and the keyshiftlever in the down or shifted position.

Other and further objects and advantages of the invention will appear as the detailed description thereof proceeds in the light of the drawing forming a part of this application and'in which:

FIG. 1 is a schematic view of one embodiment of the key lock shift mechanism embodying the present invention with some parts removed and others broken away to better illustrate the invention; 7

FIGS. 2 and 3 are fragmentary perspective views of the key lock shift mechanism in latched and unlatched positions, respectively.

The present invention may beembodied in a variety of different' typewriter keyboards and, is shownbyway of example in FIGS. l--3, in one embodiment of the structure shown in US. Letters Pat. No. 3,327,828 entitled "Keyboard Mechanism Having Latch'Meansf issued June 27,1967, to Hugh St. Lawrence Dannatt and assigned to the same assignee as the'present application. Only the structure necessary to show the invention is illustrated in FIGS. l'3. For a more complete description of the keyboard mechanism, reference may be made to the above-mentioned patent whichis he'reby incorporated by reference.

Referring now more particularly to FIGS. 1-3 of the drawing, a key lock shift mechanism-embodying the present invention is shown in a keyboard structure comprising a base plate 12, spacer bar 15, upper case or shift key levers l8 and 18b and a lower case or unshift key-lever 18a. The'key levers l8 and Home positioned in spaced relation andare supported for pivotal-motion on rod 21 and haveintegrally'formed and laterally extending rear arms 19 and 19a, respectively, which are received in individual co'rnbslots 20 and 20a of the spacer bar 15. The key levers 18,18a, and 181; are aligned with comb teeth 22 of the'spacer bar 15. The 'shiftkey lever 18 and the unshift key lever have similar features and structures which for the convenience-of the reader will be similarly numbered except that a small letter a will be added to each element associated with the unshift key 180. In the following description, the operation of the shift lever 18 will be described. However, it follows that the operation .of the unshift key lever 18a is alsodescribed by substituting the phrase unshift key lever 18a for the phrase shiftkey lever 18" and adding an aafter the numerical designation for the appropriate elements. Exceptions to this general rule will either be obvious or noted-herein. Thekey levers 18,180,181 18c are biased upwardly against a-common transverse stop'bar 23, by a comb spring 24. To minimize congestionin the vdrawing, spring 24 is shown under'key lever l8c onlyrltshouldbe understood that similar biasing springs24 are providedQunder each of the similar key leverssuchas18,1180, etc. The-unshift a plurality of key levers (not shown) which are retained in a spaced parallel arrangement. I

Elongated pawl .39 has a central longitudinal ,slot wand zis supportedfor angular and'longitudinalmovementongtheesigde of key lever "18 by enlarged hear vheadstud 41 ext eriding through the sIot40uEac'h pawl .39 isprovidedwith projection 42 which anchors-one end of bias spring; other end of which is received in aperture of projectio provided 'on the adjacent and associated key lever 11 The spring 43 biases the pawl 39 in aclockwise direction normally to engage, inthe-rest position of its associated'key lever :18, the'fo'rward end of the pawl 39 with the stop bar-23. fl'he rear end of each pawl'39 is bent over laterally to provide-anactuating'projection '45 whichextends through an aperture 460i the key lever '18 and into engageable' relation with the forwardgend of a slide member47 associated with key leverl8 andsupported for pivotal and longitudinal movement in -a manner now to be considered.

As just indicated, there is associated with key lever 18 a slide member 47. The slide member 47 is positioned in sideby-side relation with its associated key lever 18 but is maintained in slight spaced relation to the associated key lever 18 by a small dimple 48 pressed laterally from the slide member 47 and also by a short longitudinal extending plateau 49 likewise pressed laterally from the slide member 47. The dimple 48 and plateau 49 minimizes the frictional engagement between the slide member 47 and its associated key lever 18. The slide member 47 is pivotally supported on the rod 21 which is received in elongated slot 51 of each slide member 47 to permit a limited amount of longitudinal movement of the slide member 47. While the rod 21 could support and guide the rear end of each slide member 47 in its longitudinal movement, the sides of the slide member slot 51 would in such case preferably need to be polished to minimize the frictional forces involved. In practice, it is preferred to form slot 51 slightly wider than the diameter of the rod 21. The slide member 47 is provided at its rear end with overturned ear 38 which is engaged by the slightly overturned end of an individual tooth of a comb spring plate 57, secured to a sloping rear edge of the spacer bar as shown, to provide a bias force urging movement of the slide member 47 in a rearward direction and urging movement. of the rear end if the slide member 47 in a downward direction. The slide member 47 is normally latched against such rearward movement, however, by slide member latch portion 58, which engages latch roller 59 individual to the slide member 47. The latch roller 59 is rotatably journaled on a wire 60.

Upon finger depression of the shift key button 30 pivotally to depress the associated key lever 18, the pawl actuating projection 45 of the pawl 39 associated with the depressed key lever 18 engages the forward end of the associated slide member 47 and pivots it about the pin 52 while moving it slightly forward to disengage the slide member latch portion 58 from its associated latch roller 59. Upon latching disengagement of the latch portion 58 and latch roller 59, an interlock portion 62 of the slide member 47 begins to be inserted between balls 63 of an interlock structure formed by the balls 63 in a manner well known to those skilled in the art and which forms no part of the invention.

As will be evident from the drawing, the latch portion 58 of the slide member 47 has a sharply pointed nose configuration for engagement with its associated latch roller 59. So long as the apex or nose of the latch portion 58 is above the axis of the roller support wire 60, the spring bias force exerted by the comb spring plate 57 on the slide member 47 tends to move the latch portion 58 on its associated latch roller 59 upward into fully latched position of the slide member 47. Thus, if finger pressure on the shift key button 30 in pivoting the slide member 47 in the manner just explained should be released at any time prior to the time when the slide member latch portion 58 is positioned with its nose an incremental distance above the axis of the roller wire 60, the'slide member 47 will restore to fully latched position. As soon as the slide member 47 has been pivoted by finger button pressure sufficiently far that the nose of the latch portion 58 is an incremental distance below the axis of the roller wire 60, the bias force exerted by the comb spring plate 57 on the slide member 47 will cause the nose of the latch portion 58 to ride down on the now rotating latch roller 59. The slide member 47 will now begin to move longitudinally to the rear, with the latch portion 58 continuing in engagement with the now rotating latch roller 59. While this is occurring, the interlock portion 62 of the slide member 47 moves down between and rearwardly through the interlock balls 63 and the rearward longitudinal movement of the slide member 47 continues until halted by engagement of the rod 21 with the forward edge of the slide member slot 51.

The lower edge of the slide member 47 is provided with coding teeth 69 for generating coded signals in a manner described in the aforesaid Hugh St. Lawrence Dannatt US. Pat. No. 3,327,828. By providing one or more coding teeth 69 at preselected ones of the tooth positions on the slide member 47 and by omitting coding teeth from all other tooth positions thereon, the slide member 47 can, by its longitudinal movement, generate a unique code indicative of the desired shifting action and which will identify the upper case or lower case character of subsequently generated codes. The slide member 47 was unlatched for the described movement by manual manipulation of the shift key button 30.

One coding tooth 69 at a preselected tooth position is provided on all of the slide members including slide members 47 and 470 so that one common code element is generated in response to the unlatched longitudinal motion of any of the slide members such as 47 and 47a. This common code element is so controlled that it is generated later and terminated earlier than any of the other code elements generated by the remaining coding teeth 69 of any of the other slide members similar to 47 and 47a of the keyboard. The common code element also initiates a cycle of operation of the associated equipment which utilizes each coded element generated by typical slide members such as 47 and 47a. The associated equipment, after progressing through a portion of its cycle of operation, supplies return electrical energization to the keyboard to effect latch restore movement of a latch restore bail 7 The latch restore bail is comprised by a rod 743% 75 and drive member 76. In particular, the latch restore bail E is movably pivoted between a rearmost position shown i n full lines and a forward position. This is accomplished by mechanical connection of the arm 75 through a rotary solenoid operated actuator 81 as more fully disclosed in the cited Hugh St. Lawrence Dannatt U.S. Pat. No. 3,327,828.

The solenoid actuator 81 is normally maintained energized by the associated equipment to which coded data infomration is supplied by manual manipulation of the keyboard mechanism including the key shift mechanism. The latch restore bail is thus normally maintained in its rearmost position. i

The key shift mechanism includes a rocker ann lever connected between the shift key lever 18 and the unshift key lever 18a at 101 and 102, respectively. The rocker arm 100 is pivotally mounted on the pivot pin 104 which is rotatable in a bushing 106 fixed to the bracket 108. The pivot pin 104 is fixed along the length of the rocker arm lever 100 such that the length A of one side of the rocker arm lever 100 is greater than the length B of the other side of the rocker ann lever 100. in other words, A B, to compensate for the spring forces in the key shift mechanism generated by the comb spring plate 24.

The rocker arm lever 100 includes a set of upper and lower tabs 111 and 112 which are coupled to the shift key lever 18 and another set of upper and lower tabs 113 and 114 which are coupled to the unshift key lever 180. It has been found that by having the upper and

lower tabs

111, 112, 113, 114 coupled to their respective key levers 18, 18: a positive carnming of the shift key lever 18 and unshift key lever can be achieved. It should be understood, however, that the rocker arm lever 100 can achieve the same results by the use of the upper tabs 1 11 and 113 only or slots on the ends of the rocker arm lever 100 to receive the shift key lever 18 and the unshift lever 18a. The rocker arm lever 100 couples the shift key lever 18 to the unshift key lever 18a in phase opposition or, in other words, the shift key lever 18 is out of phase with the unshift key lever 180 as will be shown hereinafter. For this purpose, a means such as a bail 116 and a spring 117 fastened to base plate 12 urge the shift key lever 18 to a normally unlatched or rest position as shown by FIG. 1 while the unshift key lever 18a is disposed in the down position as shown by FIG. 1.

The key shifl mechanism also includes another shift key lever 18!; which is of similar construction to the shift key lever 18 except that the slide mechanism 47 and pawl 39 together with the associated structure is omitted since shifi key lever 18b is coupled to shift key lever 18 and hail 116. The shift key lever 18b includes a button 3017 similar to the button 30 of the shift key lever 18. The shift key lever 18b is pivotally mounted on the rod 21 and is urgedto the up positionby the spring 117 in a manner similar to the shift key lever 18.

The sequence of operations of the shiftkey lever 18 and the unshift key lever 18a is more fullydescribed in the copending application of Hugh St. Lawrence Dannatt entitled Key Shift Mechanism," Ser. No. 5 9,754, filed Nov. 1, 1967, and assigned to the same assignee as the present application. The shift key lever 18 and the unshift key lever 18a are basically the same and operate in the same manner. The shift key lever 18 is shown as being disposed in a normally up position as shown in FIG. 1, while at the same time the unshift key lever 18a is shown as being normally disposed in the down position of FIG. -1. The shift key lever 18 and the unshift key lever18a operate in asimilar manner to provide a code representing upper case and lower case'characters, and figures respective- 1 FIG. 1 illustrates the normal latched position of slide member 47 prior to manual pivotal actuation of the'shift button30 and the shift key lever 18, the latter thus engaging the stop bar 23 and the latch portion 58 of the slide member 47 being in full latching engagement with its associated latch roller 59. The latch restore bail 73 is held in its rearrnost position at this time by energization of the solenoid actuator 81 as earlier described. At the same time the unshiftkey lever 18a is normally held in the positionas shown in FIG. 1.

The shift key lever 18 may be manually depressed sufficiently far that the associated pawl 39 engages and pivots the slide member 47 beneath its point of latched engagement with thea ssociated latch roller 59. The nose of the latch portion 58 of the slide member 47 accordingly is moved below the axis of the roller wire 60, so the that latching engagement can no longer be maintained by reason of the rearward force exerted by an associated finger of the comb spring plate 57 on the slide i member 47. Since the slide member 47 is movable downward and longitudinally in a rearward direction, the nose of the latching portion 58 of the slide 'member 47 continues to engage and rotate the latch roller 59 thus to minimize any frictional forces which may be associated with the unlatching operation and thereby reduce the downward force necessarily a exertedon the key lever 18 to effect unlatching of the slide member 47. It may be noted, as illustrated in FIG. 1, that the force exerted by the actuating projection 45 of the pawl 39 on i the end of the slide member 47 maintains the pawl 39 substantially nonpivoted on the shift key lever 18 not notwithstanding the bias force exerted by the spring 43 on the pawl 39. The interlock portion 62 of the slide member 47 may be moved between adjacent balls 63 of the interlock structure to prevent similar. unlatching of any other slide member including the slide member 47a associated with unshift key lever 18a. The .unshift key lever 18a is out of phase with shift key lever 18 but follows the same sequence of operation as the shift'key lever The latch restore bail E restores any unlatched slide membersuch as members For 47a to the latched position, the action of slide member 47 will be described and it will be understood that the action of slide member 470 could be identically described by substituting theletter a after the numbers designating the appropriate elements. As the slide vanes (not shown) are pivoted by the coding teeth 69 against the bias. spring force of the code selector contacts (not shown). This bias force tends to pivot the slide member 47 upwardly at its forward end; the upper edge surface of its latch portion 58 accordingly tends to continue to maintain rolling I edeof 7 l member 47 moves rearwardly to its rea'rmost position, coding It will be recalled that a solenoid actuator 81 is deenergiz ed by the associated equipment as the latter initiated a cycle of operation and in response thereto the restore bail 73 is pivotally displaced in a forward direction causing it to e hgage the downwardly projecting restore portion 90 provided on the lower edge of the slide member 47 so that continued forward motion of the restore bail rod 74 moves the slide member 47 in a forward direction toward its relatchable position with the associated latch roller 59. The slide restore portion 90 has a sloping cam surface 91 which when engaged by the restore bail rod 74 exerts a pivotal upward force on the forward end of the slide member 47 to lift it into latchable engagement with the associated latch roller 59. Here again the continued engagement of the upper flat surface of the latch portion 58 with the latch roller 59 minimizes the frictional forces involved in the slide restore operation. The forward end of the slide member 47 while moving in a forward direction engages the side of the pawl actuating projection 45 and forces the pawl 39 forwardly on the shift key lever 18 against the tension of the spring 43 so that the slide member 47 may move in a forward direction to a fully latched position without engagement of the pawl actuating projection 45 with the upper end surface of the slide member 47. As the latch restore bail A continues its forward movement, the restore bail rod .74 begins to ride under the nose of the slide restore portion 90 and thus forcibly moves the forward end of the slide member 47 upwardly toward latching engagement of its latch portion 58 with the latch roller 59. The restored bail rod 74 moves beneath the slide restore portion 90 just after the nose of the latch portion 58 of the slide member 47 is elevated an incremental amount above the axis of the latch roller support wire 60. at which time the sloping edge surface of the latch restore portion 58 lifts the slide member 47 upward to fully latched position on the latch roller 59 by reason of the rearwardly directed force exerted by the comb spring plate 57 (FIG; 1) on the slide member 47. This disengages the slide restore portion 90 and restore bail rod 74 so that the restore bail 73 thereafter completes its forward motion without restraint by any of the latched slide members such as slide member 47. In summary, it should by observed that after depressionof shift key button 30 and the consequent depression of shift key lever 18, the slide 47 went through a cycle of motion wherein it was first moved toward the rear of the structure and then restored to the front and a latched position by the action of restore bail rod74. Thus, the slide member 47 may complete its cycle of motion even though the shift key lever 18 is held in a downward position. Furthermore, in response to the downward motion of the shift key lever 18 the unshift key lever 18a at the same timeundergoes a complimentary displacement and is now in the up position and is prepared tobe depressed by the rocker arm lever 100. in other wo'rds, the unshift key lever 18a is nowis in the same position thatgthe shift key lever 18 was at thestart (FIG. 1).

With the shift key lever 18 held in a'fully depressed or down position, the slidemember 47.may be restored to afully latched position with its interlock portion 62,out of engagement with the interlock balls 63. While the restore bail rodf7 4 underlies therestore portion 90 of all slide memberssuc-h as 47 and 470 it thereby locks them against pivotal motion unlatched position until the restore bail rod 74, hasiagain moved rearwardly sufi'iciently far as to no longer underli the restore portion 90 of any slide members. such as 476; 471;. Thus deenergization of the solenoid actuator 81, as by removal of power from the associated data utilizingeqpipment, causes the restore bailrod 74 to move to. its fors valrdv most position. where it locks all slide members such as .47 against motion in response to manual manipulation of their associated key levers (such asl8). The pawl 39 remains longitudinally displaced on the key lever 18 with the pawl actuating projection 45 yet in side abutting relation to the. end of the latched slide member 47 so that the latter cannot again be .un latched by the pawl 39 until the key lever 18 is once more restored to its normal uppermost or nonoperated position to reestablish the overlapping raation between the pawl actuating projection 45 and the end of the slide member 47 as illustrated in FIG. 1. Even though the shift key lever 18 remains so depressed for a prolonged interval, other key levers of the keyboard may be manually depressed to pivot and unlatch their respective associated slide members similar to slide 47 as soon as the restore bail rod 74 has been moved rearwardly by reenergization of the solenoid actuator 81. The unshift key lever 18a follows the same operation as that shown for the shift key lever 18 but with an out of phase, or complementary, relationship.

From the operation of the shift key lever 18 and the unshift key lever 18a, it may now be seen that the rocker arm lever 100 couples the shift key lever 18 and the unshift key lever 18a in phase opposition for upper case and lower case characters, respectively.

In accordance with the invention, the key lock mechanism includes a key lock lever 18c which is substantially of the same structure as the key levers 18, 18a, except that the key lock lever 18c includes a bridging member or tab portion 121 which coacts with the projection 35 of the key shift lever 18 for depressing the shift key lever 18 as a unit. The key lock lever 18c is pivotally mounted on the rod 21 and is urged in a clockwise direction by the comb spring plate 24. There exists a first adjustable space between the projection 35 and the tab portion 121. This first space is effectively a built-in time delay for the sequential operation of the key lock lever 18c and the shift key lever 18. That is, when the key lock lever 18c is operated, the tab portion 121 moves through the space before it coacts with the projection 35. The key lock mechanism also includes a locking member 122 which is pivotally mounted on the key lock lever 180 by a pivot pin 124. The locking rriember 122 is retained laterally by a washer member 125 in a manner well-known to those skilled in the art. The locking member 122 is yieldingly urged in a clockwise direction by a spring 126. The spring 126 is retained at end 129 in an aperture 127 in the key lock lever 18c and is retained at the other end by an upturned portion 128 coacting with the locking member 122. The locking member 122 includes a notch portion 130 which coacts with the bar 23 for retaining the key lock member 18c in a depressed position which in turn retains the key shift member 18 in a depressed position by the tab 121 acting on the vertical projection 35. The key lock mechanism also includes a bridging member 131 which is fixed to a vertical projection 132 of the key shift lever 18 and includes a portion 133 which coacts with the locking member 122 to retain or urge the locking member 122 in a counterclockwise direction when the key shift lever 18 is depressed. The tab 121 and the bridging member 131 bridge other key levers, such as key lever 9 shown in fragmentary view. This gives added flexibility to the design of the keyboard. The portion 133 of the bridging member 131 is positioned in cooperative relationship with the locking member 122 such that the locking member 122 engages the bar 23 when the key lock lever 18c moves at the end of its limit of travel. Another or second space or second clearance exists between the locking member 122 and the portion 133 of the bridging member 131. This second space or second clearance is greater than the adjustable space or clearance between the tab 121 and projection 35 and provides a time delay between the operation of the key lock lever 18c and the shift key lever 18. The depression of the shift key lever 18 releases the key lock mechanism. This second clearance or spacing allows the locking member 122 to rotate clockwise to engage the stop bar 23 when the key lock lever 18c is depressed. However, when the shift key lever 18 is operated before the key lock lever 180; it closes the second space or second clearance between portion 133 and member 122 and exerts a counterclockwise force on the locking member 122 to retain'it in a substantially counterclockwise position to avoid engagement with the bar 23 during its upward travel.

FIGS. 2 and 3 show the locking member 122 in a locked position and in an unlocked position, respectively. It should be noted that when the locking member 122 is in the lock position, the portion 133 of the bridge member 131 is spaced from the locking member 122 by the second clearance which is sufficient for the notch to engage the bar 23. Referring to FIG. 3, the locking member 122 includes a tab portion 137 which coacts with the key shift lever 18 for depressing the key lock lever when a force is exerted on the locking member 122 by the portion 133 of the bridging member 131.

In the operation of the key lock mechanism, the shift key lever 18 may be locked in a shift position by the depression of the lock button 134. When the lock button 134 is depressed, the tab portion 121 moves through the small clearance between the vertical projection 35 and the tab portion 121 to effect a short time delay during which the space between the portion 133 and the locking member 122 increases. This may be seen by observing the position of the pin 124 on the key lock lever18 as it is depressed. Since this distance is increased and the locking member 122 is biased in a clockwise direction, the notch 130 engages the stop bar 23 locking the key lock lever 18c and the shift key lever 18 in the shifted position. During this shift operation, the shift key lever 18 and the unshifi key lever 18a together with their associated

slide members

47, 47a operate in the manner set forth hereinbefore. When it is desired to unlock the shift key lever 18, the shift key button 30 is depressed so that the bridging member 131 and the portion 133 rotate the locking member 122 in a counterclockwise direction to disengage the notch 130 from the stop bar 23. The comb spring plate 24 continuously urges the key lock lever 180 in an upward direction. Thus, the pivot pin 124 is also moved in an upward direction to decrease the gap or space between the portion 133 and the locking member 122 to a point at which it contacts the portion 133. This in turn urges the locking member 122 in a counterclockwise direction to keep the notch 130 away from the stop bar 23 and thus permits the shift key lever 18 to return to the unshifted position as previously described.

From the foregoing description, it may be seen that the key lock mechanism provides for the positioning of additional key levers between the key lock lever 18c and the shift key lever 18. Thus, greater variety in the arrangement of the keyboard can be achieved by the utilization of the present invention.

While there has been described a specific form of the invention for purposes of illustration, it is contemplated that numerous changes may be made without departing from the spirit of the invention.

I claim:

1. A key lock mechanism for a keyboard having a plurality of key levers including a shift key lever which is movable between a normally unshifted position and a shifted position. said key lock mechanism comprising:

a. a key lock lever mounted in spaced relationship to said shift key lever for movement between corresponding normally unshifted and shifted positions;

b. a fixed bar;

c. locking means including a spring biased locking member pivotally mounted on said key lock lever for latching said key lock lever in said corresponding shifted position when moved thereto;

d. a first bridging means mounted on said key lock lever and coupled to said shift key lever for urging said shift key lever to said shifted position; and

e. second bridging means mounted on said shift key lever and coupled to said locking member for decoupling said locking member from said fixed bar when said shift key lever is shifted before said key lock lever.

2. The invention defined in claim 1 wherein said key lock lever is spaced from said shift key lever by at least one key lever.

3. The invention defined in claim 1 wherein said key lock lever is spaced from said shift key lever by at least one key lever and said first and second bridging means span said one key lever.

4. The invention defined in claim 1 further including a lock button on said key lock lever for operating said key lock lever.

and said shift ke of said tab portio y lever being responsive to the displacement n.

6. The invention defined in claim member is pivotally disposed on a piv lock lever 1 wherein said locking ot pin fixed to said key

Claims

1. A key lock mechanism for a keyboard having a plurality of key levers including a shift key lever which is movable between a normally unshifted position and a shifted position, said key lock mechanism comprising: a. a key lock lever mounted in spaced relationship to said shift key lever for movement between corresponding normally unshifted and shifted positions; b. a fixed bar; c. locking means including a spring biased locking member pivotally mounted on said key lock lever for latching said key lock lever in said corresponding shifted position when moved thereto; d. a first bridging means mounted on said key lock lever and coupled to said shift key lever for urging said shift key lever to said shifted position; and e. second bridging means mounted on said shift key lever and coupled to said locking member for decoupling said locking member from said fixed bar when said shift key lever is shifted before said key lock lever.

5. The invention defined in claim 1 wherein said first bridging means includes a substantially horizontal tab portion and said shift key lever being responsive to the displacement of said tab portion.

6. The invention defined In claim 1 wherein said locking member is pivotally disposed on a pivot pin fixed to said key lock lever.