US2727688A - Keyboard control mechanism - Google Patents

Description

Dec. 2o, 1955 H, P, LUHN 2,727,688

KEYBOARD CONTROL MEOHANISM Filed OCL. l, 1951 4 Sheets-Sheet l ATTORNEY 4 Sheets-Sheet 2 Filed Oct. l 1951 Inl-Il-IJIIIII lNVENTOR HANS P LUHN /v//ZA/m,

ATTORNEY Dec. 20, 1955 H. P. LUHN KEYBOARD CONTROL. MECHANISM 4 Sheets-Sheet 3 Filed Oct. l, 1951 F l G 4 ATTO RN EY Dec. 20, 1955 H. P LUHN 2,727,688

KEYBOARD CONTROL MECHANISM Filed OCT.. l, 1951 4 Sheets-Sheet 4 INVNTOR HANS P. LUHN ATTO RNEY United States Patentg O KEYBOARD CONTROL M EcHANlsM Hans P, Luhn,y Armonk, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application October 1, 1951, Serial No. 249,112

17 Claims. (Cl. 23S- 145) This invention relates to an improved keyboard structure. More particularly, the invention relates to electric keyboards.

It is an object of the invention to provide a keyboard having a reset mechanism of a highly exible nature. This objective is attained in a keyboard having a plurality of denominational banks of keys and a latching bail associated with each key bank for latching a depressed key in operative position by providing in such structure means for manually resetting any given bank of keys, and electromechanical means to which the resetting devices of the respective banks may be selectively connected for either manual or electromechanical resetting of such selectively connected bank, without in any way impairing the individual manual reset function.

It is a further object of the invention to provide in a keyboard of the kind indicated, positive means for preventing depression of a vkey of any given bank wherein a key has previously been depressed. This objective is attained by providing -an improved key latching mechanism having means adapted to coact with a lock-out shoulder on the 'key stems etective when .one key has been'depressed to interpose a lock-out lug in the path of the lock-out shoulder on the key stems of the remaining keys. A second key cannot be depressed, therefore, in any given bank unless a key previously depressed in such bank has been released.

It is a further object of the invention to provide in a keyboard improved key releasing or reset mechanism and particularly such mechanism for the 'release of depressed keys that is electromechanically operated only upon deenergization of an electromagnetic reset control device.

It is a further object of the invention to provide key stemlocking meansthat will `prevent the simultaneous depression of ladjacent keys.

It is a further object of -theinvention to provide improved indicating means that will show at a glance the position of any depressed keys.

Other objects and 'advantages of the invention will appear asfthe particular description thereof proceeds in light of ythe drawings forming a part of this application, and in which drawings:

Fig. l is a plan view of thekeyboard; Y

Fig. 2 is a cross-sectional View through the keyboard on line 2--2 of Fig. 1; l n v Fig. 3 is a sectional View through a bank of keys on line 3-3 of Fig. 2; l y v Fig. 4 is an enlarged, fragmentary view of a key bank showing in particular the key control bail and associated -mechanism for controlling operation of the bail;

2,727,588 Parenteel wee. 26, 1955 Fig. 8 is a sectional View on line 8 8 of Fig. 7; and

Fig. Sa is a modied key stem.

The keyboard device i@ includes a plurality of key banks, each bank containing a plurality of keys. Herein the keyboard is illustrated as consisting of twelve banks of denominational keys i2. Each bank of keys is supported on a separator casting M which has formed on opposite faces thereof key latching bail guide channels 16 adapted to receive therein for sliding movement a pair of key latching bails Opening through opposite faces of the separator casting litare a plurality of cavities 2i), in which key return springs may be located. Opening through the lower edge of the casting 1.4 are spaced key stern guide slots 22.

A plurality of keys i2 are mounted for reciprocating movement on each face of the separator casting 14. Suitable guide webs may be provided to restrain the keys to a xed, reciprocatory path.

Each of the keys l2 may be formed of a light-conducting material, such as for example, methyl methacrylate resin which is known by the trade-name Lucite Lucite has the property of conducting light rays along the length of a body thereof without material loss in a lateral'direction. The Lucite key proper is fixed to a key stem 212-, which includes a downwardly extending terminal portion 26. in one form of the invention, a Lucite lightconducting member Z3 is adapted to overlie the key stems and hold them in operative position with respect to the separator casting i4. The light-conducting member Ztl is attached to the separator casting by means of screws 3@ at each end thereof. The light-conducting member 2S is notched to provide accommodation for the inner terminus i251 of each key. in its non-depressed position, the Lueite head of the key if. is free of its related notch in the light-conducting member Ztl. However, when a key is depressed, the inner terminus 12a thereof moves into overlapping relation with a face of its related notch in the light-conducting member 28. This arrangement permits the passage of light from a suitable source along the light-conducting member 28 and into the key l2 so that the face of a depressed key will be illuminated while in depressed position.

A light shield 32 is interposed between the separator casting M and each of the associated light-conducting members 2li. The light shield includes a laterally bent ange 54 which is generally coincident with the bottom edge of the light-conducting member Furthermore, the shield includes key shielding projections 36 which extend upwardly between adiacent keys and erectively prevent transmission of light from one key to another.

Each of the key stems 245 includes a laterally extending lug 38 which is adapted to enter the spring retaining cavity 2i) provided for the respective keys. The lug is adapted to contact one end of a compression spring itl seated at its other end against the bottom wal of the return spring cavity 20. it will appear, therefore, that the keys are normally spring-biased to inoperative or non-depressed position, operation or depression of a key being against the force of the compression spring di).

The key terminal 26 has an int` rned end which is adapted to enter the guide slot 22 and thereby stabilize the reciprocatory movement of the key mechanism. Each key stem has attached to the face thereof a Contact closing boss 44 which serves the dual function of closing a pair of contact points, as will be pointed out in greater detail hereinafter, and of limiting the upward movement of the 4key under the influence of the key return spring Kid. The

upper face of the contact closing boss de is adapted to abut the ange 34 of the key shield 32 when the key is held in its inoperative position by the key return spring The length of the key terminal 26 is such that Contact between Contact closing boss ed and the key shield flange 34 is established before the inturned guide finger 42 comes into full contact with the end wall of the key stem guide slot 22.

It will be noted by reference to Figs. 3 and 4 that the contact closing boss 44 has an outwardly flared face which is adapted to contact an extending end 46 of a leaf spring contact member 48, thereby moving the contact member 48 against an inturned end S0 of a companion spring leaf contact S2, thereby closing the contact points. The contact member 52. is provided with an incurled end 54 at which suitable electrical connections may be made.

It will be appreciated that an electrical contact device such as described in the foregoing paragraph is associated with each of the denominational keys of the keyboard, a plurality of such, for example, being shown in Fig. 2 of the drawings. Each plurality of contact points constituting an assembly for a single bank of keys is supported on an insulating contact support strip 56. The latter is attached to the separator casting 14 by means of screws 58 passing through the ends of the contact support strip 56 and into the separator casting 14.

It will be evident from the foregoing that whenever a key 12 is depressed against the tension of the key return spring 40, the contact closing boss 44, carried by the key stem 24, will move into contact with the contact strip terminal 46 and move the same laterally into contact with the inturned end 50 of its companion terminal strip 52, thereby establishing an electrical circuit through the contact strips.

Means have been provided herein for holding an operated key in depressed position. This means consists in the key latching bail 18 which is designed to cooperate with means on the key terminal 26, whereby the bail 18 is shifted in its guide channel 16 and wherein certain of the key terminal and bail surfaces coact to latch a depressed key in its depressed position and at the same time effectively lock the remaining keys of the bank against operation until the depressed key has been released.

With more specific reference to Fig. 4 of the drawings, it will be noted that the key latching bail 18 is a channellike member which includes a laterally extending key lock-out ange 60 and a laterally extending bail operating ange 62. The flanges 60 and 62 are parallel in respect to each other and extend outwardly from the face of the key latching bail 18.

The bail operating flange 62 has formed therein a series of bail lugs 64, there being one such lug for each of the associated key stems. Each of the key terminals 26 has formed therein a bail cam 66, which is adapted to contact the bail lug 64 and reciprocate the key latching bail 18 in its guide channel 16. Furthermore, the key terminals 26 have formed therein a latch shoulder 68 over which the bail lug 64 will engage when a particular key has been depressed. ln this regard it is to be noted that the key latching bail 18 is biased into key latching position because the upper end 7 0 thereof is connected to a spring contact member 72. It is clear from the foregoing that when a key is depressed, its bail cam 66 will contact the bail lug 64 and reciprocate the key latching bail 18 against the tension of the spring contact 72. Complete depression of the key will position the same with its latch shoulder 68 in a plane below the bail lug 64, whereupon the key latching bail 18 will move under the inuence of the spring contact 72 to engage the bail lug 64- over the latch shoulder 68. This is effective to retain the depressed key in its depressed position against the tension of its key return spring 40.

Appropriate mechanism has been provided herein for releasing latched keys in all or a selected number of the key banks. By reference to Fig. 4 of the drawings it will be seen that the lower end of the key bail 18 has a pair of flanges 74 and 76 which serve rotatably to mount a bail control member 78. The bail control member 78 is in the form of a pin having a square upstanding shaft 80 which is of suicient length to enter a square socket in an operating knob 82. The operating knob 82 is located for sliding movement in a frame slot 84 by means of a pair of stop collars 86 and 88. The body 90 of the operating knob 82 located immediately below the stop collar 86 is squared to t the width of the frame slot 84. When, therefore, the square body 90 is seated in the frame slot 84, the operating knob 82 may be moved without turning from one end of the slot 84 to the other for manual control. Rotation of the knob 82 in its normal position is cffectively prevented by the squared body 90. Provision has been made for rotating the knob 82 and its associated pin and to this end the stop collar 88 is spring-pressed against the under side of the frame 92 by means of a spring 94 which rests on a fixed collar 96. The body of the operating knob 82 below the collar 88 and the body is cylindrical and the connection between the shaft socket of the operating knob 82 and the squared end 80 of the pin 78 is telescopic, so that the operating knob 82 may be lifted axially in respect to the shaft 80 against the tension of the spring 94, thereby presenting the cylindrical surface of the operating knob 82 within the frame slot 84. This position permits turning of the knob 82 and the consequent turning of the pin 78 and its shaft 80.

Certain selective bail control mechanism has been provided herein, whereby each bail may be latched against release, whereby it may be selectively operated by either manual means or by electromechanical means, and whereby it may be selectively operated by one of a plurality of combined mechanical and electromechanical means. The control mechanism involved is best shown in Figs. 2 and 4 of the drawings. Located transversely at the bottom of the keyboard are a pair of restoring bails 98 and 100. These bails are generally U-shaped to provide at their ends a pivot bearing 102 about which they may rock. The pivot bearings 102 are supported on a pair of diametrically opposite bearing lugs carried by the frame structure 92. The bail 98 has an upwardly extending operating arm 104 attached to one end thereof, while the bail has an identical operating arm extending from the opposite end thereof. A solenoid 106 is located at each side of the keyboard for electromechanically rocking the bails 98 and 100. The solenoid 106 in Fig. 2 of the drawings has a core 108 to which the operating arm 104 of the restoring bail 98 is pivoted. The operating arm of the bail 100 disposed at the opposite side of the keyboard is similarly connected to its operating solenoid. It follows, therefore, that when the solenoid 106 is energized and its core 108 is drawn inwardly, the operating arm 104 and consequently its connected operating bail 98 will be rocked about the bearing point 102 in a counterclockwise direction or downwardly, as shown in Fig. 2 of the drawings. An identical function follows in respect to the restoring bail 100 when its operating solenoid is energized. The foregoing structure provides means for electromechanically rocking the restoring bails 98 and 100. Such rocking movement may be utilized to selectively release one or more key latching bails and consequently depressed keys in a key bank controlled by such bails.

Herein, each of the bail control members and particularly the shaft 80 thereof has provided a laterally projecting lug 110 and a pair of angularly spaced projecting lugs 112 and 114. Each of the lugs 110, 112 and 114 is spaced along the axis of the shaft 80 so that appropriate rotation of the shaft will bring a selected one of the lugs into cooperative relation with an intended cooperating element. Specifically, when the operating knob 82 is in the position shown in Figs. 2 and 4 of the drawings, the projection 110 on the shaft 80 will lie in contact with the restoring bail 100, so that counterclockwise movement of the restoring bail 100 will move the key bail 18, associated with that particular control mechanism, into key releasing position. As heretofore described, the operating knob 82 may be lifted against the tension of the spring 94 to permit rotative movement thereof. By rotating the knob 82, the projection 114 may be brought into registration with the restoring bail 98, whereby rocking movement of this latter bail in a counterclockwise direction about its pivot point afanes@ 102, Fig. 2, will actuate thekey late hing bail 18 to. release a depressed key. 1t will be observed that in neither of the described positions of the operating knob 82 is the knob latched against manual operation to release avkey latched by the key latching bail under the control of the knob. Consequently, the key latching bail may be selectively operated either electromechanically or manually in either of the positions described.

Should it be desired positively to latch the depressed key of a given bank against release without further manual manipulation, the control knob S2 may be further rotated to bring the projection 112 into abutting relation against an inturned iiange 116 formed in the support frame 92. Such position of the parts will prevent movement of the operating knob 32 in the frame slot 84 until the knob is again lifted and turned to take the projection 112 out of contact with the flange 116. lt will be furthermore noted that the operating lever 104 associated with the restoring bails 98 and 100 have a restoring button 118 aixed thereto so that the restoring hails 98 and 100 may be manually rocked simply by depressing the appropriate restoring button 118.

lt has been intimated heretofore that the keyboard is so constructed as to prevent the depression of a key of any given bank of keys while another key in that bank is depressed. To this end the key lock-out ilange 60 of the key latching bail 1S has formed therein a plurality of lock-out lugs 12b which constitute interposers adapted to lie in the path of a lock-out shoulder 122 on each key terminal 26 whenever the key latching bail 18 has been moved downwardiy by depression of a key in the key bank under its contro-l. The parts referred to are best seen in Fig. 4 of the drawings, where the lower key is in depressed position and the bail lug 64 overlies vthe latch shoulder et; of the depressed key. The remaining keys of the bank shown in Fig. 4 are now positively blocked against depression by reason of contact between'the key lock-out lugs 12b and the associated lock-out shoulders 122. Upon release of the depresed key, however, the key latching bail 1S will move upwardly under the influence of the spring contact 72, whereby the lock-out lugs 120 will move out of the operative zone of the lock-out shoulders 122. Under these conditions another key of the bank may be depressed.

lt has been described heretofore that the light conducting member 2S is adapted to provide illumination for a depressed key in one form of the invention. In that form of the invention an elongated lamp 124 is mounted on a frame bracket 126. The lamp 124 extends across the width of the keyboard, and therefore constitutes a common light source for illuminating each of the light-conducting members 23 in the keyboard. For the purpose of providing distinctive illumination for the several key banks, there is interposed between each of the light-conducting members 28 and the lamp 124 a four-sided light lter 128. A. cylindrical end of the filter element 128 is mounted in the bracket 126, and a cylindrical operating shaft 13b extends through a positioning plate 132 attached to the frame 92. 'f his mounting permits manual rotation of the lter elements 128. Two adjacent, angularly disposed sides ot' the filter element 128 constitute suitable color filters, as for example, red on one side and green on the other. lhus, by positioning the iilter element 128, either one or the other of the color tiltery surfaces may be interposed between the lamps 124 and the light conducting member 28 associated with the particular lte'r. By reference to Fig. l oi the drawings, it will be noted that each of the key banks has associated therewith a color filter so that an operator may by means of colored light distinguish one bank or group of banks from any other bank or group of banks.

'ln Figs. Z through 4 of the drawings is illustrated a' key latching mechanism wherein the key lock-out flange and the bail operating iiange are unitary. ln Figs. through Sor the drawing is shown a comparable structure in which the key lock-out flange and the bail operating ange constitute separate although interconnected elements. By this latter arrangement there is achieved an extra control over the keys which is particularly eiective during the electrical readout cycle of the keyboard. lt is contemplated that compatible elements of the first described form of the invention be embodied in the modied form and vice versa, but only such parts of the mechanism in the modified structure that ditt'er from the iirst will be described in detail herein.

In the modied form of the invention the key latching bail channel los accommodates a key latching structure consisting of a key lock-out iange 61M and a separate bail operating ange 62a. The bail operating ange 62a has a series of laterally projecting bail lugs 64a which as seen in Fig. 5 of the drawings are normally positioned at the forward key stem edge at bail cam surface 66a. Since the bail operating iiange 62a is free to slide in the key latching bail channel 16a, it is apparent that depression of any of the keys 12a will force the bail operating ange 62a downwardly as viewed in Figs. 5 through 7. The upper end of the key latching hail 18a integral with the flange 62a has an upturned portion 121 including a laterally projecting iinger 12in which is in contact with the Spring arm '72a of a normally closed contact point. it follows, therefore1 that any downward movement of the key latching bail 13a will be against the tension of the Contact spring arm 2n. lt is further apparent that the spring arm 7211 will tend to return the key latching bail 18a to its normal position whenever released.

The key stems are provided with latch shoulders 68a which are adapted to engage under the related bail lugs 64a to latch in depressed position any key that has been operated. The structure thus far described is sufficient to latch a key in depressed position.

As in the first described form of the invention, there is provided in the modified form of the invention means for locking out all other keys of a bank when one key of the bank has been depressed. in this regard reference is had to the key rock-out Flange tribal and particularly to the laterally extending lock-out ings 12th: extending therefrom and into proximity to the key stems. .in the modified form of the invention a lock-out lug 12110 cooperates with each of the non-operated key stems to lock them in normal position whenever any key in the bank has been depressed. The edge 12de of each key stem constitutes a camming surface which cooperates with an associated lock-out lug 12de to move the key iock-out flange 69a downwardly as viewed in Figs. 5 through 7, and thereby position the remaining lock-out lugs 12tlg under the lockout shoulders 122@ of the undepressed key stems. By inspection of the drawings it wiil be seen that the normal position of the key stem camming surfaces 66a and 124a in reference to the related bail lugs 64a and lock-out lugs 12th? is such that the key latching bail 18a is operated immediately upon the initial portion of the key depression, whereas the key lock-out iiange 641m is not picked up for operation until the key has been depressed through substantially half its stroke. Thus, upon depression of a key, the depressed key itself is latched in depressed position and all other keys of the bank are latched against depression.

'Ihe key lock-out fiange ou@ is mounted for free movement in the key latehing bail channel 16a against the tension ol' a spring 12651 which has one end thereof attached to the key lock-out ilange den and the other end thereof to a stud 12851 which is fixed in the separator casting 14a and extends through an elongated slot 134i@ at the end of the key lockout flange 60a. it will be seen that the key lock-out flange 66a tends to return to normal position under the inuence of the spring 126e.

The bail release post 8bit is mounted in the end of the key lock-out ilange oda; and since the key lock-out flange 60a and the key latching bail 18a are separate elements, some means must be provided for transmitting bail release avances motion from the key lock-out fiange 60a to the key latching bail 18a. It will be recalled in connection with the first described form of the invention that each key has a return spring 40 associated therewith. In similar manner the modified form of the invention has key return springs 40a associated with each of the key stems so that when a depressed key stem is released from the influence of the bail lug 64a, the stem will return to its normal position. In order to operate the key latching bail 18a for the release of a depressed key from the infiuence of the bail lug 64a that is holding it in depressed position, there is provided in the modified form of the invention an interlock between key lock-out flange 60a and the key latching bail 18a. The upstanding portion 121 of the key latching bail 18a has pivoted thereto a pawl 13241. The pawl has an upwardly disposed nose 134 which is adapted to engage a laterally extending lug 136 formed at the end of the key lock flange 60a.

The nose 134 of the pawl 132e is normally out of engagement with the lug 136 but is so designed as to move into engagement with the lug whenever the key latching bail 18a is operated by depression of a key. To the end that this function may follow, the pawl 132:1 has formed therein a cam slot 137 which cooperates with a stud 138 that is fixed in the separator casting 14a from which it extends into the cam slot 137 of the pawl 132a. Thus, whenever the key latching bail 18a is moved downwardly under the infiuence of key operation as viewed in Fig. 6 of the drawings, the nose 134 of the pawl 132 will be elevated into the path of the key lock-out flange lug 136. With the foregoing structure in mind, it is apparent that downward or releasing movement of the key lock-out fiange 60a will be transmitted to the key latching bail 18a so that the latter will be drawn downwardly to disengage the bail lug 64a from restraining contact with the latch shoulder 68a of a depressed key.

The release post 80a is attached to the key lock-out ange 60a for better control of the keyboard during readout thereof. It was noted in connection with the first described form of the invention that energization of the release solenoid 106 functions to release depressed keys in any banks connected therewith for such purposes. In that form of the invention, however, release of the depressed keys followed immediately upon enerso that full key release does not take place until the j readout function has been completed.

The mechanism that permits this operation, and to which the modified form of the invention is directed involves the lock-out lugs 120H and an upper surface 122b of the lock-out shoulders 122a. By reference to Fig. 6 of the drawings it will be observed that key depression has resulted in the latching of the depressed key 12a in depressed position by engagement of the bail lug 64a with the latch shoulders 68a and the locking out of the remaining keys by the interposition of the lock-out lugs 120H into the path of the lock-out shoulders 1220 of the remaining keys of the bank. In this position as viewed in Fig. 6 the lock-out lug 12fia immediately to the rear of the depressed key stern is so positioned as to afford no interference to the return of the depressed key to normal position. During release movement of the latching bail 18a, however, the key lock-out fiange 60a is moved downwardly and such movement is sufficient to position the lock-out lug 120e immediately to the rear of the depressed key into overlying and blocking relation with the upper edge 122b of the key lock-out shoulder 122a thereof, so that the depressed key stem is prevented from returning to normal position until the key lock-out flange 60a is released for full return under the influence of its return spring 126e. The position of the parts just described is best shown in Fig. 7 of the drawings.

It will be noted by reference to Fig. 7 of the drawings that initial movement of the key lock-out fiange 60a will pick up, for movement therewith, the key latching hail 18a by virtue of the pawl interlock 132:1. By reference to Fig. 6 of the drawings it will be seen that the lock-out shoulder 122e of the depressed key is spaced slightly below the lock-out lug e to the rear of the depressed key. Therefore, when the key latching bail 18a is moved downwardly to release a latched key, the bail lug 64a will be withdrawn from blocking contact with the latch shoulder 68a of a depressed key stem, and the stem will move upwardly under the influence of its related spring 40a. However, before the latch shoulder 68a has been released, the lock-out lug 120e behind the depressed key is moved into blocking position in respect to the upper edge 122b of the lock-out shoulder. In this position the Contact button 44:1 is still effective to hold closed the contacts 46 and 50 (as in Figs. 2 and 3), and the complete return of the key to normal position does not follow until the key lock-out flange 60a is released and returned to its normal position by means of its return spring 126a.

Study of keyboard operation discloses that errors committed thereon generally involve the depression of adjacent keys. In the belief that most operational errors resulting from incorrect key depression may be eliminated by rendering it impossible to depress adjacent keys there has been embodied in the modified form of the invention a key stem lock effective for this purpose. Reference to Figs. 5 through 7 of the drawings will show a hall lock cooperating with both of adjacent keys to prevent simultaneous depression of adjacent keys of a given bank. The ball lock 140 is retained in an aperture formed in the guide web 142 constituting a part of the separator casting 14a. In facing surfaces of adjacent keys and at the area of the ball retaining aperture in the guide web 142 is a generally arcuate recess 144 for accommodating the locking ball 140. The size of the generally arcuate recesses 144 when opposite each other is sufficiently larger than the diameter of the ball 140 to permit free operation of any one only of the keys. However, should an attempt be made to depress adjacent keys, the ball 140 will engage the adjacent keys and prevent depression thereof. Fig. 5 illustrates the normal position of the ball lock 140 when neither of its related keys has been depressed. In Figs. 6 and 7 the second key from the bottom of the bank has been depressed, and consequently these figures will illustrate the locking function of each associated ball 140 in respect to the adjacent key, i. e. the key at the bottom of the bank and the key which is third from the bottom. It will be noted that the ball 140 has by contact with the normal face of the depressed key been moved laterally into full engaging contact with the face of the recess 144 in the lower key of the bank. When the ball 140 occupies the position illustrated in Figs. 6 and 7, depression of either of the locked keys is prevented by the locking balls 140 in addition to the locking means including the lugs 120a.

As a further aid to accurate keyboard operation, there has been provided herein a visual indication to assist the operator in quickly locating any key he may have depressed. The visual aid in the modified form of the invention is mechanical in nature and wholly independent of the illumination of depressed keys as described in connection with the rst form of the invention. Reference to Figs. 5 through 8 will show that each key of a bank excepting the bottom key of such bank has a target 146 on the lower edge thereof. The keyboard casmamas ing above the upper key is preferably upturned to provide a surface on which targets for the upper row of keys is provided. The target or spot 146 is in contrast with the key stem itself so that when exposed it will mark the position at which a key of the bank has been depressed. The contrasting spot 146 is so positioned on each of the keys that it is hidden from View by the key immediately in front of it until such key is depressed. Depression of a key will, however, expose the indicating spot or target 146 on the key immediately to the rear of the depressed key and will visually indicate the location of the depressed key. Figure 8a shows a modified target that includes the number of the key directly 'torward thereof.

In the principal form of the invention the key stems are retained in the separator casting channels by means of the light transmitting element 28. inasmuch as the form illustrated in Figs. through 8 of the drawings, however, is designed for use in an unilluminated keyboard, a key retaining member 28a of any suitable form may be substituted for that shown in Figs. 2 and 3 of the drawings. This member also serves to conne the locking balls 14@ in position in their associated recesses. T be modied keyboard differs also in respect to the manner in which a bank of keys may be locked against reset. In the modied form of the invention a flange .llos is provided for contact with a lateral stud 12a ot' the operating stem 80a to inhibit the necessary nal upward movement of the key lock-out flange during release thereof.

Having described the invention in an operative form, what is claimed as new and patentable is the following:

l. ln a keyboard, a bank of keys, a key latching mechanism associated with said bank for sliding movement in respect thereto, a control member mounted on the end of said mechanism, an actuating bail for operating said control member for releasing a depressed and latched key, means for manually actuating said control member for operating its related key latching mechanism, and means associating said control member and said actuating bail for the actuation of said control member by said actuating bail.

2. in a keyboard, a bank of keys, a key latching mechanism associated with said bank for sliding movement in respect thereto, a control member mounted on the end of said mechanism, an actuating bail for operating said control member for releasing a depressed and latched key, means for manually actuating said control member for operating its related key latching mechanism,

means associating said control member and said actuating bail for the actuation of said control member by said actuating bail, and means for locking said control member against actuation.

3. in a keyboard, a bank ot' keys, a key latching mechanism associated with said bank for sliding movement in respect thereto, a control member mounted on the end of said mechanism, a pair of actuating bails for operating said control member for releasing a depressed and latched key, means for manually actuating said control member for operating its related key latching mechanism, means selectively associating said control member and said actuating bails for the selective actuation of said control member by either of said actuating bails.

i.. in a keyboard, a bank ot keys, a key latching bail associated with said bank for sliding movement in respect thereto, a control member mounted on the end of said bail, an actuating bail for operating said control member for releasing a depressed and latched key, means for manually actuating said control member for operating its related key latching bail, means associating said control member and said actuating bail for the actuation of said control member by said actuating bail, and electromechanical means for operating said actuating bail.

5. ln a keyboard, a bank of keys, a key latching bail associated with said bank for sliding movement in respect thereto, a control"membermounted. on the` end of said bail, an actuating bail" for operating said control member for releasing a depressed and .latched key, a` rotatable pin for associating said control member and said actuating bail for the actuation of said control member by said actuating bail when said pin is in one rotational position, means for manually actuating said control member for operating its related-key latching bail, and means for lockingV said control member against actuation when said pin is in another rotational position.

in keyboard, a bank of keys, a key latching bail associated with said bank for sliding movement in respect thereto, a control membermounted on the end of said bail, an actuating bail for operating said control member for releasing a depressed and latched key, a rotatable pin carried by said control member, an abutment extending laterally from said pin for associating said control member and said actuating bail for the actuation of said control member by said actuating bail when said pin is in one rotational position, means for manually actuating said control member for operating its related key latching bail, and a second abutment extending laterally from said pin for locking said control member against actuation when said pin is in another rotational position.

7. ,En a keyboard, a plurality of banks of keys, a key latching bail associated with each of said banks for sliding movement in respect thereto, a control member mounted on an end of each of said hails, an actuating bail common to said control members, means for manually actuating said control members for operating their related key latching bails, wd means for selectively associating said control members and said actuating bail for the actuation of said control members by said actuating bail.

8. ln a keyboard, a plurality of banks of keys, a key latching bail associated with each of said banks for sliding movement in respect thereto, acontrol member mounted on an end of each of said bails, an actuating bail common to said control members, means for manually actuating said control members for operating their related key latching balls, means for selectively associating said control members and said actuating bail for the actuation of said control members by said actuatbail, and means for locking said control members against actuation.

9. ln a keyboard, a plurality of banks of keys, a key latching bail associated with each of said banks for sliding movement in respect thereto, a control member mounted on an end of each of said bails, a pair of actuating bails common to said control members, means for manually actuating said control members for operating their related key latching bails, and means for selectively associating each of said controlmernbers respectively and either of said actuating bails for'the selective actuation of each of said control members by a. selected one of said actuating bails.

lo. in a keyboard, a plurality of banks of keys, a key latching bail associated with each of said banks for sliding movement in respect thereto, a control member mounted on an end of each of said bails, a pair of actuating bails common to said control members, means for manually actuating said control members for operating their related key latching bails, means for selectively' sociating each of said control members respectively and either of said actuating bails for the selective actuation of each of said control members by a selected one of said actuating bails, and individual electromechanical means for selectively operating said actuating bails rel spectively.

1i. in a keyboard, a plurality of banks of keys, a key latching bail associated with each of said banks for sliding movement in respect thereto, a control member mounted on an end of each of said balls, an actuating bail common to said control members, a rotatable pin for selectively associating each of said control members and said actuating bail for the actuation of said control members by said actuating bail when said pin is in one rotational position, means for manually actuating said control members for operating their related key latching bails, and means for locking said control members against actuation when said pin is in another rotational position.

12. In a keyboard, a plurality of banks of keys, a key latching bail associated with each of said banks for sliding movement in respect thereto, a control member mounted on an end of each of said bails. an actuating bail common to said control members, a rotatable pin carried by each of said control members, an abutment extending laterally from said pin for selectively associating said control members and said actuating bail for the actuation of said control members by said actuating bail when said pin is in one rotational position, means for manually actuating said control members for operating their related key latching bails, and a second abutment extending laterally from said pin for locking said control members against actuation when said pin is in another rotational position.

13. In a keyboard, a key bank support, a plurality of keys mounted on said support for reciprocatory movement in a fixed path, a key stem ixed to each key, a key latching bail common to said keys mounted for sliding movement in said support, a pair of spaced, parallel flanges on said bail, a latch shoulder on each of said stems, bail lugs in one of said llanges, means on each of said stems cooperating with said bail for engaging a lug and the latch shoulder of a key during depression thereof, a key lock-out shoulder on each of said stems, and key lock-out lugs on the other of said flanges operative upon sliding movement of said bail and movable into locking relation to said lock-out shoulders on nonoperated keys.

14. In a keyboard, a key bank support, a plurality of keys mounted on said support for reciprocatory movement in a xed path, a key stem fixed to each key, a key latching bail common to said keys mounted for sliding movement in said support, a latch shoulder on each of said stems, lugs on said bail, means on each of said stems cooperating with said bail for engaging a lug and the latch shoulder of a key during depression thereof, a lock-out shoulder on each of said stems, a lock-out bail mounted for sliding movement in said support, a surface on each key stem operative on said lock-out bail for moving said bail in said support upon depression of a key, and means on said lock-out bail and movable therewith into locking relation to said lock-out shoulders on nonoperated keys.

l5. In a keyboard, a key bank support, a plurality of keys mounted on said support for reciprocatory movement in a fixed path, a key stem fixed to each key, a key latching bail common to said keys mounted for sliding movement in said support, a latch shoulder on each of said stems, lugs on said bail, means on each of said stems cooperating with said bail for engaging a lug and the latch shoulder of a key during depression thereof, a

lock-out shoulder on each of said stems, a lock-out bail mounted for sliding movement in said support, a surface on each key stem operative on said lock-out bail for moving said bail in said support upon depression of a key, means on said lock-out bail and movable therewith into locking relation to said lock-out shoulders on non-operated keys, and means for moving said bails to key stem release position,

16. In a keyboard, a key bank support, a plurality of keys mounted on said support for reciprocatory movement in a xed path, a key stem fixed to each key, a key latching bail common to said keys mounted for sliding movement in said support, a latch shoulder on each of said stems, lugs on said bail, means on each of said stems cooperating with said bail for engaging a lug and the latch shoulder of a key during depression thereof, a lock-out shoulder on each of said stems, a lock-out bail mounted for sliding movement in said support, a surface on each key stem operative on said lock-out bail for moving said bail in said support upon depression of a key, means on said lock-out bail and movable therewith into locking relation to said lock-out shoulders on non-operated keys, means connected to said lock-out bail for moving the same to key stem release position, and a separable connection between said key latching bail and said lock-out bail for imparting movement to said key latching bail upon movement of said lock-out bail.

17. In a keyboard, a key bank support, a plurality of keys mounted on said support for reciprocatory movement in a fixed path, a key stem xed to each key, a key latching bail common to said keys mounted for sliding movement in said support, a latch shoulder on each of said stems, lugs on said bail, means on each of said stems cooperating with said bail for engaging a lug and the latch shoulder oi' a key during depression thereof, a lock-out shoulder on each of said stems, a lock-out bail mounted for sliding movement in said support, a surface on each key stem operative on said lock-out bail for moving said bail in said support upon depression of a key, a lug on said lock-out bail, means on said lock-out bail and movable therewith into locking relation to said lock-out shoulders on non-operated keys, means for moving said key latching bail to key release position, and means interconnecting said key latching bail and said lock-out bail whereby key release movement of said key latching bail is transmitted to said lock-out bail to position said lockout bail lug in blocking relation to the lock-out shoulder of a depressed key.

References Cited in the le of this patent UNITED STATES PATENTS 769,614 Kelling Sept. 6, 1904 1,040,705 Leppert Oct. 8, 1912 1,808,213 Eichenauer June 2, 1931 1,810,399 Horni June 16, 1931 2,176,640 Payne Oct. 17, 1939 2,210,099 Shipley Aug. 6, 1940 ...tsaar-e

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