US2135377A - Telegraph transmitter - Google Patents

Description

Nov. 1, 1938. R. F. DIRKES ET AL TELEGRAPH TRANSMITTER Filed Aug. 22, 1935 5 Sheets-Sheet l llllll INVENTORS RF. DIRKES BY 6. I. RQBERTS ATT RNEY Nov. 1, 1938. R. F. DIRKES ET AL TELEGRAPH TRANSMITTER Filed Aug. 22, 1935 5 Sheets-Sheet 2 QB PM INVENTOIE RF. DIRKES G. LROBERTS 1938. R. F. DIRKES ET AL 2,135,377

TELEGRAPH TRANSMITTER Filed Aug. 22, 1955 5 Sheets-Sheet 3 IIII-lllll YINVENTORS RF. DIRKES BY G'. l. ROBERTS ATTORNEY Nov. 1, 1938. R. F. DIRKES ET AL TELEGRAPH TRANSMITTER Filed Aug. 22, 1935 5 Sheets-Sheet 5 O 3 5 I w G 5 I 7 F. m a 5 I A 5 & w 9 Iw9 M R44 Ml" a2d xv n I u I z 5. 12:5 8 M a 9 4 3 a s 1 1 G 5 I In F 6/ 6 w 7 5 ZK A 2 w 7 4 a w 5 INVENTORS R F DIRKES BY 6.]. ROBERTS -T' ME ATTORNEY Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE 2,135,377 TELEGRAPH TRANSMITTER Application August 22, 1935, Serial No. 31,402

'24 Claims.

This invention relates to transmitters for printing or selective telegraphs and more particularly to apparatus of this nature which is integral with and controlled by an associated keyboard.

The preferred embodiment of this invention is adapted for use with a telegraph system known as the simplex or start-stop system, wherein the signals comprise permutations of impulses corresponding to two different line conditions extendmg throughout a definite number of time intervals. The selecting intervals or impulses of each signal are preceded by a starting impulse or interval of uniform line condition-and followed by a stopping or rest impulse or interval which is always the same and of opposite line condition from that of the starting impulse.

It is a custom in telegraph practice to further distinguish the two different line conditions by referring to them as intervals during which marking or spacing impulses are transmitted. The marking impulses correspond to intervals during which current is transmitted and the spacing impulses correspond to intervals during which no current is transmitted. In the preferred embodiment of the invention the transmitting mechanism is adapted to transmit a spacing impulse for the start impulse and a marking impulse for the rest impulse. V

A simplex system may be operated from a distributor transmitter in conjunction with a tape transmitter and a perforated tape. However, from the standpoint of economy and reduced equipment required, it is more often desirable to operate simplex systems directly from a unit comprising a combined keyboard and distributor transmitter. Accordingly, one of the objects of this invention is to provide a keyboard controlled transmitting mechanism of improved efficiency and durability which will transmit to a telegraph circuit combinations of code impulses corresponding to and representing, according to a predetermined arrangement, actuated key levers.

Another object of this invention is to provide a keyboard transmitter in which it is impossible to depress more than one key lever at a time.

Still another object of this invention is to provide a keyboard transmitter in which it is impossible to depress a subsequent key lever until the complete transmission of the code combinations of impulses representing the previously depressed key lever.

Still another object of this invention is to provide a keyboard transmitter in which, if an actuated key lever is held depressed for a length of time longer than is necessary for the transmission of the associated code combinations of impulses, said code combinations of impulses will not be repeated. i

These and further objects of this invention will hereinafter appear.

The preferred embodiment of this invention contemplates the employment of a mechanism selectively responsive to the actuation of keys and key levers for controlling a plurality of current controlling contacts in various combinations, ac-

cording to the signal character to be transmitted, in conjunction with a distributor mechanism for distributing the current impulses to a telegraph circuit in the proper sequential order.

The main structural part of the machine comprises a hollow cast metal base or frame upon and in which the various combinations and subcombinations of the associated mechanisms and parts are mounted. The keys and key levers are arranged in substantially the same manner as those of an ordinary typewriter and are adapted to actuate a series of permutation or selecting bars in various combinations according to the actuated key lever. The selecting bars are provided with beveled slots therein in a manner well known in the art and are operatively engaged with asso- .ciated individual members which in conjunction with an independently rotatable cam sleeve and a series of contacts, transfer the combinations of mechanical selections of the selecting bars, according to a predetermined arrangement, into associated and corresponding combinations of electrical impulses.

As hereinbefore stated, this invention is adapted to operate in conjunction with a simplex signaling code, and five time intervals are employed during which combinations of impulses are transmitted, exclusive of the starting and stopping impulses. It is to be understood, however, that with modifications the invention may be adapted to operate in conjunction with other codes.

The maximum number of possible combinations of impulses available with a five unit code is 32 and in order to transmit the requisite number of characters comprising numerals, letters, punctuation marks and printer functions, case grouping of signals is employed. Accordingly two case shift signals are employed called a shift signal and an unshift signal. As is well known to those versed in the art, the shift and unshift signals are printer functions. The purpose of the shift sig- 1 nal is to position the receiving recorder so that the following received combinations of impulses will be properly recorded in the figures group. The purpose of the unshift signal is to position the receiving recorder so that the following re ceived combination of impulses will be properly recorded in the letters group. Thus, two characters may be common to one key lever and which of these two characters will be recorded is dependent on the last case shift signal transmitted. Some of the selections are common to both case groups such as the letter space signal and some punctuation marks.

A more complete and thorough understanding of the invention may be had from the following detailed description taken in conjunction with the accompanying drawings forming a partof this specification showing preferred and modiiied embodiments thereof in'which:

Figure 1 is a plan view of a preferred embodiment oi the invention in which the front of the machine is shown at the bottom of the draw- Figure 2 is a front elevational view thereof;

Figure 3 is a left end elevational view thereof;

Figure 4 is a right end elevational view thereof Figure 5 is a sectional view taken on the line 5-5 of Figure 1; I

Figure 6 is an enlarged fragmentary sectional view taken on line 8-8 of Figure 3;

Figure 7 is an enlarged fragmentary sectional view taken on line 1-1 of Figure 3;

Figure 8 is an enlarged fragmentary sectional view taken on lines 8-8 of Figures 1 and 8;

Figure 9 is an enlarged fragmentary sectional view taken on line 3-8 of Figure 3 showing a part of the mechanism in its normal condition;

Figure'10 is a view showing the mechanism shown in Figure 9 in its operated position;

Figure 11 is a circuit diagram of the preferred embodiment of the invention;

Figure 12'is a circuit diagram of a modified form of the invention; and

Figure 13 is a fragmentary sectional view similar to that of Figure 7 showing the location of an addition contact adapted to be used in conjunction with the modified form of the invention. 4

Referring first to Figure 1 in which some of the mechanism is shown dotted, there is provided a hollow case base or frame II comprising the main structural part of the invention upon and in which the various mechanisms and elements of the invention are mounted. As is evident from Figure 1, the arrangement of the character keys issubstantially the same as that of any wellknown three row typewriter keyboard. The keys 2! are mounted on the front end of associated ke'y levers 28 which are pivotally mounted at their rear ends on a rod 23 which is supported in a series of brackets 34, one of which is better shown in Figure 9, attached to the inside of the base II. The rod 23, (Fig. 1) is provided with nuts 25 in threaded engagement with the ends thereof which prevents the rod from moving longitudinally. The key levers 25 are prevented from moving longitudinally and are guided in their vertical movement by vertical slots 21 and 15 (Figs. 2 and 5) individual to each key lever in front and rear guide plates 28 and 3| respectively. The front guide plate 28 is attached to a front vertical section of the base II by screws 32. Right and left selecting bar guide brackets 33 and 34 (Figs. 1, 8 .and 5) are attached to the inside of the base by screws 35 and 35 respectively and, attached to them by screws" is the rear guide plate 3|. Each key lever 28 is provided with a single wire spring-38 (Figs. 1 and 5) which tenth to elevate the front end thereof. One end of each spring 38 is engaged in a notch 38' in its associated key lever, theother end-being located in an individual hole in a spring mounting bar 35 attached to the inside of the base by screws 4|. Situated directly beneath and extending horizontally in a direction at right angles to the key levers are a series of five selecting bars indicated in general at 42 in Figure 6 and individually by reference characters 42a to 42a in Figures 1 and 5. The selecting bars 42 are adapted to slide transversely-and are guided by individual slots 43 and 44 (Figs. 1 and 5) in the guide brackets 33 and 34 respectively. Rollers 45 individual to each selecting bar are pivotally supported on rods 48 (Fig. 3) in the selecting bar guide brackets 33 and 34 and upon these rollers the selecting bars rest, thereby permitting said bars to slide with a minimum amount of friction. Each of the selecting bars 42 has thereon a different arrangement of upwardly extending bevelled projections 41 (Fig. 6) which are so arranged that the bars will slide transversely from left to right in various combinations as various key levers are depressed. When any one of the key levers 25 is depressed, the lower edge of the lever engages the bevelled projections 41 of the selecting bars 42 and actuates them transversely in accordance with a predetermined (Fig.8) secured in the brackets 5| and 52 are pivotally mounted a group of five selecting bar levers indicated in general at 54 in Fig. 6 and individually by reference characters 54a. to 546 in Figs. 1 and 5. An arm 55 (Fig. 6) of each selecting bar. lever extends downwardly through a hole in the base 2| and is engaged by a U- shaped slot 58 in the left end of an associated selecting bar 42. Thus transverse movement of the selecting bars 42 causes the selecting bar levers 54 to rock about their pivot mounting point. The selecting bar levers are kept in alignment with their respective selecting bars by the slots 43 in the left selecting bar mounting bracket 33 and spacers 51 (Fig. 5) on the lever pivot rod 53.

The transmitting mechanism of the preferred embodiment above mentioned will now be described. Its principal function is to transfer the mechanical selections of the selecting bars into corresponding sequential electrical impulses. It

performs this function by means of an independently rotatable cam sleeve, a series of contacts, contact levers and associated parts.

A horizontal transmitting cam shaft 58 (Figs. 3, 5 and 8) is journaled at the front end in a flanged bushing 53 (Fig. 8) supported in the bracket 5| by a nut 80. A bracket fil secured to the base II by screws 52 supports a bearing sleeve 53 by means of nuts 84 which serves as another journal for the shaft 58 adjacent the rear end thereof. A gear hub 85 is attached adjacent the rear end of the shaft 58 for rotation therewith by a screw 58. Secured to the gear hub 85 by screws such as 81 is a helical gear 88 adapted to mesh with another helical gear or pinion 89 on the drive shaft 1| of an electric motor M. The electric motor M is arranged for continuous rotation and therefore the transmitting cam shaft will be continuously rotated by means of the gears 58 and 58. Loosely mounted on the front section of the transmitting cam shaft 58, which is of reduced diameter, is a cam sleeve 12 in abutting relation with the flanged bushing 59. A series of might disc cams 13a to 13f, 14 and 15 disposed on the cam sleeve 12 in a predetermined arrangement between intermediate spacers 16 are clamped for rotation therewith by a nut 11 in threaded engagement with the end of the cam sleeve. tated with the transmitting cam shaft 58 by means of a hereinafter described ratchet or grab clutch. The clutch comprises a driving member or sleeve 18 and a driven member or sleeve 8|. The driving member 18 is fixed to the shaft 58 for continuous rotation therewith by a screw 19. Teeth 82 disposed on the left face (Figs. 5' and 8) of the driving sleeve 18 are adapted to operatively engage similar teeth 83 disposed on the right face of the driven member 8|. The driven member 8| loosely mounted on the shaft is operatively engaged with the cam sleeve 12' by. means of inter-engaging tooth members 84. The

driven member 8| is thus engaged with the cam sleeve 12 for rotation therewith, but is adapted to slide along the transmitting shaft 58 to bring its teeth 83 into or out of engagement with the teeth 82 on the driving member 18. The means by which the driven member 8 I is actuated along the shaft 58 will be hereinafter described. A circular coiled spring 85 disposed between flanges 86 and 81 on the driven member and cam sleeve respectively normally tends to keep the driven member 8| engaged with the driving member 18.

The left edge of the flange 86 of the driven member 8| as seen in Figure 3, extends axially to form a side cam surface 88 which is adapted to operatively engage a cam follower 89. In the normal or rest position of the cam sleeve 12, the cam follower 89 is engaged with the wide part of the cam surface 88 and thus holdsthe sleeve member 8| to the front as shown in Figure 3 and its teeth out of engagement with the teeth on the driving member 18.

A transmitter start magnet mounting bracket 9| (Figs. 1 and 7) is attached to the left top section of the keyboard base 2| by screws 92. Attached to a vertical section 93 of the bracket 9| by screws 95 is a magnet base 94 and a transmitter magnet composed of two electro-magnetic coils 96. An armature lever 91 (Figs. 3, 7 and 8) is pivotally mounted adjacent the center thereof on a pin 98 supported by the bracket 9|. Rigidly attached adjacent the lower end of the armature lever 91, is the start magnet armature 99 in operative relation with the pole pieces |0| of the start magnets 96. A spring I02 (Figs. 1 and 7) attached to the lower end of the armature lever 91 normally keeps the armature lever in its unoperated position whereupon the cam follower 89 (Fig. 3) integral with the upper end thereof is adapted'to engage or be in the path of the side cam surface 88. Upon the energization of the magnet 96, the armature lever 91 is rocked in a clockwise direction as seen in Figure 7 to cause the disengagement of the cam follower 89 (Fig. 3) and the side cam surface 88. Thereupon the driven member 8| is free to slide along the shaft 58 by action of the spring 85 and bring its teeth 83 into engagement with the teeth 82 on the driving member 18. The driven member 8| and the cam sleeve 12 will thereupon rotate with the transmitting cam shaft 58 until the clutch members are forced apart as will be hereinafter described in conjunction with the description of the means for energizing the start magnet 96 to initiate the rotation of the cam sleeve 12.

Pivotally mounted at their lower ends on a the cam sleeve 12.

The cam sleeve 12 is adapted to be rorod I08 supported in the brackets 5| and 52 (Fig. 8) are fivecontact lever hammers I04 in operative relation with associated cams 13a to 13c on These hammers I04 will be rocked about their pivot mounting point as is evident fom Figure 6, in the desired sequential order by their associated cams as the cam sleeve 12 revolves. They are kept aligned with their associated cams by spacers I05 intermediate with each hammer. In operative relation with each hammer I04 (only one of which is shown in Fig. 6) are associated T-shaped contact levers IBM to |06e (Fig. 1) which have the right top part thereof bifurcated to receive the rod I01 (Fig. 6) onto which they are urged by springs I08 individual to each'lever. The rod I01 and a rod I 09 to which the stationary ends of the springs I08 are attached are secured in the upper part of the brackets 5| and 52. A set of six spring contacts Illa to If (Fig. 3) normally tending to open by means of their spring tongues are mounted between insulating bars 2 attached to the brackets 5| and 52 by screws-H3 (Fig. 6). Individual pieces of insulating material III attached to the upper end of each spring tongue IIIa to la press against the left top arm I I0 of associated contact lever I06. In the rest position of the cam sleeve 12 the cam 13], as shown in Figure 2, actuates a rest contact lever 6 which is pivoted on the rod I03 so that the upper end thereof engages the insulating material III on the tongue of contact |I|,f to close said contact. The contact levers I06a to |06e (Fig. 1) are adapted to be actuated by their associated hammers I04 and cams 13a to 136 respectively (Fig. 8) to close the contacts II Ia to I I Ie in predetermined arrangements as will be hereinafterdescribed. The downwardly extending arm of each vcontact lever I06 (Fig. 6) is adapted to be operatively engaged with a vertical projection II 4 on the left end of a substantially horizontal arm of its associated selecting bar lever 54.

. A U-shaped universal bar II5 (Figs. 1, 5 and 10) pivoted at the ends on the rod 23 normally has the top edge of the cross part thereof held in contact with the bottom edge of the key levers 26 by a spring II5' attached to a pin H1 in the universal bar and to a spring post H8 in the base 2|. The universal bar 5 is adapted to be rocked about its pivot point whenever the key lever 26 is actuated. A bracket 9 (Figs. 9 and 10) attached to the left side of the universal bar II5 carries a pivot pin I2I, on which is loosely mounted a transmitter start magnet contact operating member I22. Another bracket I23 fixed to the underside of the base 2| by screws I24 has in its lower end a shoulder screw I25 upon which the tongue I26 (best shown in Fig. 5) of a contact I 21 is pivotally and insulatively mounted. The back stop of the contact is insulatively mounted on a bracket I28 attached to the bracket I 23. A spring I29 insulatively attached to the tongue I26 and to a spring post I3I in the bracket I23 tends to keep the tongue in contact with its back stop. With the cam sleeve 12 in its rest position (Fig. 9) the contact operating member I22 is adapted to operatively engage with the tongue I26 to open the contact I21 when an actuated key lever nears the limit of its downward movement. Referring to the circuit diagram (Fig. 11) the contact I21 is shunted around the coils of the transmitter start magnet 96. Thus when the contact I21 is open the magnet 96 will be energized which as hereinbefore described actuates the armature lever 81 (Fig. 3) to disengage the cam follower 89 and side cam surface 88 which initiates the rotation of the'cam sleeve I2.

The operation of the various mechanisms on the actuation of a key lever will now be described in conjunction with the transmission of its associated code combination of impulses. As sume that a key lever 26 representing the letter A" is to .be depressed and according to a prearranged signaling code its respective five Impulses are I and 2 marking and 3, 4 and 5 spacing. In the preferred embodiment the marking position of the selecting bars 42 is to the left as seen in Figure 6 and the spacing position is to the right. Accordingly the beveled edges 41 on the selecting bars are so arranged that when the A" key lever is depressed the selecting bars 42a and 42b (Fig. 1) will be slid to the left into their marking position and the selecting bars 42c to 42: will be slid to the right into their spacing position. With a selecting bar 42 (Fig. 6) in its marking or left position, itsassociated selecting bar lever 54 will be in its marking position as shown by the full lines in Figure 6. Similarly when a selecting bar is in its spacing or right position its associated selecting bar lever 42 will be in its spacing position as shown by the dotted lines in Figure 6.

Assume that the A key lever is depressed and after the selecting bars 42a to 42c have practically reached their respective positions the contact I21 (Fig. 5) is opened and, as described, causes the disengagement of the side cam surface 88 (Fig. 3) and cam follower 89. The driven member 8l of the clutch is thereupon free to slide to the left by action of the spring 85 and cause its teeth 83 to engage the teeth 82 on the driving member 18 whereupon thecam sleeve I2 will rotate with the shaft 58. When the cam sleeve is in its predetermined rest position, the cam 13] (Fig. 2) actuates the rest contact lever II8 to close its associated rest contact III] which as shown in the circuit diagram Figure 11 completes the circuit from battery to line. Referring again to Figure 11, battery I32 is connected through appropriate resistance I34 over conductor I35 to the tongue of contacts Illa to IIIe in parallel, and thence over conductor I36 to the contact I21 in parallel with the coils 96 of the transmitting start magnet and then over conductor I31 to the tongue of contact If. The back stops of the contacts Illa to III! are connected in parallel to the outgoing line or telegraph circuit I38. Shortly after the cam sleeve I2 starts to rotate, the high part of cam I3! (Fig. 2) passes out of engagement with the rest contact lever H6 and allows the contact III! to open by means of its spring tongue. Before the high part of any of the other cams 13a to He (Figs. 6 and 8) engage their respective hammers I84, there is an interval equal to about one-seventh of a revolution of the cam sleeve when all the contacts Illa to II If are open. As this disconnects the battery I32 (Fig. 11) from the line I38, there is therefore shortly after the start of every revolution of the cam sleeve an interval in which no current is transmitted to the line I38 and it is known as the start impulse. This conforms with the code combination of impulses employed in which a no current or spacing impulse is transmitted for the start impulse. As-the cam sleeve rotates further the high part of cam 130 (Fig. 6) starts to engage its associated hammer I84 and rock it -IIIG.

in a counter-clockwise direction about its pivot. The hammer in turn starts to rock its associated contact lever ma in a clockwise direction with the rod I81 serving as a pivot. As will be remembered, the selecting bar 42a was actuated to its marking position and consequently the selecting bar lever 54a will be-in its marking position. With the selecting bar lever in this position, the lower end of the contact lever M611. is adapted to operatively engage the projection II4 on the right arm of the selecting bar lever 54a as the cam 13a and associated hammer rock the contact lever. Therefore as the hammer I84 is rocked further the lower end of the contact lever I86a will engage the projection H4 and thereafter the contact lever l86a will rock in a counter-clockwise direction with the lower end thereof in contact with the projection I I4 acting as a pivot point. The bifurcated upper end of the contact lever will slide to the left on rod I81 and allow the arm II8 to close the contact As there is but little clearance between the lower end of the contact lever and the projection II4, the contact lever will be rocked in a counter-clockwise direction to close the contact Illa shortly after the cam 13a starts to engage the hammer I84. The hammer I84 remains in contact with the high part of the cam 13a for about one-seventh of the revolution of the cam sleeve and consequently keeps the associated contact Illa closed for a substantially equal length of time. The hammer I84 in passing out of engagement with the high part of the cam 13a allows the attached spring I88 to return the contact lever I86a and associated hammer I84 to their normal unoperated position whereupon the contact la is allowed to open by action of its spring tongue. Referring again to Figure 11, it is evident that while contact Illa is closed, battery I32 is connected to the line I38 and thus an interval of current is transmitted. This corresponds to the first impulse, which is marking, of the code combination of impulses of the selected character representing the letter A. As the high part of the cam 13a is passing out of engagement with its associated hammer I84, the high part of the cam 13b starts to engage its associated hammer I84. The selecting bar lever 54b being in its marking position, the contact IIIb will be closed by its associated contact lever I86b, in the same manner as contact Illa was closed and thus transmit to the sending circuit another marking impulse which corresponds to the second impulse of the code combination of impulses representing the letter A. In the preferred embodiment of the invention the contacts I Ila to I I Ie and earns ciated hammer about its pivot mounting point.

As described above, the selecting bars 42c to 42s in their spacing position will actuate their 8550-.

ciated selecting bar levers 54c to, 546 to their spacing position. This renders the projection M4 onsaid selecting bars, as shown by the dotted selecting bar lever inFigure 6, out of the path and therefore unengageable with the lower ends of their associated contact levers I060 to I06e. Thus as the hammer I04 rocks in a counterclockwise direction it will cause its associated contact lever I06c to pivot about the rod I01 with practically no horizontal movement of the arm H and therefore contact IIIc will remain open. Referring again to the circuit diagram Figure 11, all the contacts In to If being open allows a no current impulseto be transmitted to the line which corresponds to the third impulse of the code combination of impulses representing the letter A. Contacts II Id and Ira are allowed to remain open as the high part of their respective cams engage their associated hammers in the same manner as contact II Ic was allowed to remain open. Accordingly the fourth and fifth impulses are impulses of no current and are transmitted to the line and correspond to the fourth and fifth impulses representing the selecting character. Referring to Figures 2, 5, 6 and 11, as the cam sleeve 12 nears the end of its revolution, the hammer I04 associated with the cam I3e disengages the high part of said cam whereupon the high part of cam 13) actuates its associated rest contact lever I I6 to again close the rest contact If. This connects battery to the line and thus transmits the marking rest impulse. While the cam 13 is engaged with its contact lever II6, the cam sleeve I2 will be brought to rest in its predetermined rest position at the completion of one revolution thereof as will be hereinafter described. Referring to Figure 11 in conjunction with the above paragraphs, it is evident that shortly after the cam sleeve started to revolve there was an interval when all the contacts II I a to III I were open. Thus an interval of no current was transmitted which corresponds to the start impulse of the signal. On the following two intervalscontacts II Ia and I I Ib respectively were closed and consequently transmitted to the line two intervals of current. As no contacts were closed for the next three intervals, three intervals of no current were transmitted. On the last part of the revolution of the cam sleeve the contact I I I ,1 was again closed to transmit the rest impulse of the signal. Thus the five impulses representing, according to a predetermined arrangement, the letter A preceded by a spacing start impulse and followed by a marking rest impulse were transmitted.

Pivotally mounted on pins I39 and MI (Figs. 2, and 6) in the brackets 5I and 52 respectively, is a U-shaped selecting bar lever lockingmember I42. A roller cam follower I 43 pivotally carried on a shoulder screw I44 in an arm of the member I42 is inoperative relation with the cam I4 on the cam sleeve I2. The cross section I45 (Fig. 6) of the locking member I42 is wedge-shaped and is adapted to be operatively engaged with the hooked upright arms I46 of the selecting bar levers 54. A spring I41 attached to the locking member tends to keep the cam follower I43 engaged in its associated cam I4. When the cam sleeve I2 is in its rest position, the cam follower I43 is engaged with the high part of the cam I4 and therefore the cross section I45 of the locking member is out of engagement with the hooked ends I46 of the selecti'ngbar levers. When the cam sleeve I2 has rotated a few degrees from its rest position, the high part of the cam I4 passes out of engagement with the follower I43 and the spring I4! is allowed to raise the locking member I42. Thereupon its wedge section I45 will engage with either the right or left side of the hooked ends I46 of the selecting bar levers 54a. to 546, depending on their respective positions as shown in Figure 6 by the dotted outline of the wedge section I45 and a hooked end I46. Near the end of the revolution of the cam sleeve I2, the high part of -the cam 14 again engages the cam follower and actuates the locking member I42 to disengage. the wedge section I45 thereof from the hooked ends I46 of the selecting bar levers. The locking member I42 thus holds the selecting bar levers in their actuated positions during substantially the whole revolution of the cam sleeve I2 and prevents them from moving during the transmission of the code combination of impulses which their position represents.

A mechanism is provided whereby a subsequent key lever can not be depressed until the transmission of the code combination of impulses corresponding to the previously actuated key lever has been completely transmitted, which prevents the subsequent code combination of impulses from breaking in on the previous combination of impulses. This mechanism called the safety device also provides means whereby the code combination of impulses transmitted will not be repeated if its associated key lever is held depressed for a longer length of time than is necessary for the transmission of said impulses. Thus if repeat signals are desired, the key lever must be returned to its, normal position and depressed again at the end of the transmission of the first combination of impulses as allowed by the safety device which will now be described.

Pivoted on a shoulder screw I48 (Fig. 1) in the bracket 52 is a bell crank I49 (Figs. 9 and Pivotally carried on a shoulder screw I5I in an arm of the bell crank I48 is a roller cam follower I 52 in operative relation with the cam I5. A spring I53 attached to the bell crank keeps the cam follower I52 engaged with the cam I5. The downwardly extending arm of the bell crank I 48 extends through a hole in the base 2| and carries on the lower. end thereof a pin I54 on which is pivoted the left end of a link I55. The right end of the link I55 is pivoted on a pin I56 carried in the upper end of a lever I 51. The lever I51 is fixed for rotation therewith to a rod I58 supported by a bracket I59 (Figs. 3 and 5) which in turn is attached to the underside of the base 2 I. Also fixed to the rod I58 for rotationtherewith is a collar I 6| and a hammer I62 which is in operative relation with the contact operating member I22 (Figs. 9 and 10). Pivotally mounted on the end of the rod I58 is a universal bar stop arm I63 which is limited in its pivoting with respect to the collar I6I (Fig. 5) by,a notch I64 (Figs. 9 and 10) in the stop arm engaging with a pin I65 carried in the collar I6I. A spring wire I66 coiled about the collar has one end engaged by the stop arm I63 and tends to rotate the stop arm in a clockwise direction as seen in Figs. 9 and 10 so as to keep the left side of the notch I64 against the pin I 65. A retractile spring I61 attached to the contact operating member I22 and to a bracket I68 attached to the universal bar I I5, keeps the hammer I62 and contact operating member I 22 engaged. Fig. 9 shows the position of a part of the safety mechanism when the transmitter cam sleeve I2 is in its rest position. The depression of a key lever, as heretofore described, actuates the universal bar H5 and contact operating member I22 to open the contact I21 during the last part of the stroke of said key lever 26, whereby to initiate the rotation of the cam sleeve 12. Shortly after the cam sleeve starts rotating, a notch m in the cam is passes out of engagement with the follower III and consequently rocks the bell crank I, and by means 'of the link Ill and arm ill. rocks the rod I" and collar Iii in a clockwise direction into the position shown in Fig. 10. For this cycle of operation of the keyboard, it will be assumed that the actuated key lever 20 was released immediately after being depressed. whereupon the key lever and universal bar Ill will return to their normal position. Now, as the hammer I" and stop arm I rock withthe rod lll,-the hammer I! will allow the-spring ill to pull the contact operating member in out of operative relation with the'tongue I! of the contact ill and the stop arm I will be in a position with the upper end thereof beneath the universal bar Iii. Therefore, no key leve'r ll can be depressed an appreciable amount since they are blocked by the universal bar "I coming-in contact with the top of the stop arm I. As is apparent from the shape of the cam ll-the stop arm "I and hammer I62 will remain as shown. in Fig. 10 for practically the complete revolution of the cam,

,(Fig. 3) to return to its unoperated position.

whereupon the cam follower II integral with the upper end thereof, will be in the path of the side cam surface ll. As the cam sleeve II nears the end of a'revolution, the cam follower 00 engages the side cam surface I and due to the shape of the side cam surface, causes the driven member-li to slide to the right on the transmitting cam shaft and consequently disengage itsteeth 83 from the teeth I! on the driving member ll. 'Ihe'driven member ll continues to rotate due to its inertia until a further projection of the side cam surface 08 engages the cam follower II and stops the cam sleeve 12 and associated parts in their predetermined rest position. From the above description it is apparent that a second key lever can be operatively actuated only after the completion of the on of the code combination of impulses corresponding to the preceding actuated key lever. Ihis prevents the premature starting of ton of a second combination of impulses before the complete transmission of the preceding combination.

The operation of the safety mechanism will now be described in coniunction with the transmission of a combination of impulses when the associated actuated key lever is held down for a length of time longer than is necessary for the transmission of said impulses. The rotation of the cam sleeve .will be initiated as'usual by the actuation of a key lever, whereupon it proceeds to transmit the representative combination of the hammer I02 rotating with the rod ill allows the spring i" to slide the lower end of the contact operating member iii to the right and out of engagement with the tome I28 of the contact ill. The contact if'l then closes and causes the cam sleeve I2 to be stopped when it reaches its predetermined rest position as hereinbefore de-. scribed. As the rod Ill rotates from its first position, the spring I brings the top of the universal bar stop arm I against the side of the universal bar II! where it remains until the rod in rotates into its normal position as the cam follower ill drops into the notch in the cam ll at the end of the revolution of the cam sleeve.

As'thero'd Ill and the hammer I" rotateto their normal position, the hammer rocks the con-v tact operating member If! and causes the lower end thereof to come in contact with the side of.

the contact tongue. if. and further rotation of the hammer I62 causes the slot in the upper end of the contact operating member I22 to slide on the pin lfi. Thus the contact I21 cannot be opened to initiate the rotation of. the cam sleeve I! for another cycle of operation until the actuated key lever has been returned to its normal position. When the universal bar ill finally rises, it causes the contact operating member- If! to disengage with the side of the contact tongue I" and allows the spring I" to return it to its normal position where it is again in operative relation with the upper face of the contact tongue, as shown in Fig. 9. If, in the above described cycle of operation, the depressed key lever had been released during the transmission of its associated combination of impulses, the spring I" would have urged the universal bar stop arm I beneath the universal bar III and as described in the first cycle of operation, prevented the actuation of the same or another key lever until after the combination had been completely transmitted. The key levers controlling the release 'of the cam sleeve are therefore adapted to be actuate only when the cam sleeve has very nearly mpletedits revolution or is in its predetermined rest position. As an appreciable length of time is required to actuate a key lever, the cam sleeve is certain to be brought to a stop in its predetermined rest position at the end of every revolution before it can again be released.- This assures that the associated recorder will start every cycle of operation in correct phase relationship with the transmitting keyboard.

This keyboard is intended primarily for use in conjunction with an associated recording unit i to'the recording unit.- It is to be understood,

however, that the "keyboard may be used as a separate unit by providing a motor M to continuously rotate the gear 68, such a motor being shown in Fig. 3. v'I'he combined units may be used to alternately receive or transmit in which case the selector magnet of the. recorder is connected in series with the outgoing line.

A Bakelite block Ill (Figs. 1 to 4) mounted on posts I'll, is attached to the base II by screws I'll. Attached to the Bakelite block "8 are a series of spring clips I18 which are adapted to make electrical connections with similar clips on 15 the associated recorder unit. Four posts 'II'I secured in the four corners of the base 2| serve as guides for a silencing cover used to keep dust and dirt out of the combined units. A series of four rubber feet I18 attached to the underside of the base casting prevents the keyboard from resting directly on a table or other supporting means. Ample space is provided in the rear of the keyboard housing for attaching resistances and condensers that may be used in conjunction with a motor governor. The letter space key lever 26', which is the first key lever from the left, engages with a pin I19 (Figs.' 1 and 3) on the left arm of a space key lever operating member I8I. The space key operating member supports an elongated space key I82 at the center of the keyboard and is pivotally mounted on screws I83 (Figs. 2 and 5) in blocks I84 attached to the keyboard base 2I.

A modification is shown in Fig. 13 which is adapted to be used in conjunction with the preferred form of the invention. The modification consists of a contact I85 which is connected in series with the rest contact I I If as shown in the modified circuit diagram (Fig. 12). This contact I85 is insulatively mounted by screws I86 to the start magnet mounting bracket 9| and is closed in its normal position. The tongue of the contact has an insulating block I81 attached to its upper end which is adapted to be operatively engaged by a contact operating member I88 attached to the upper end of the armature lever 91. When the start magnet 96 is deenergized, the contact I85 will be closed by action of its spring tongue and when the start magnet is energized, the contact operating member I88 is adapted to open the contact I85 simultaneously with the release of the cam sleeve I2 and prior to the opening 'of the contacts If by the cam 13). Referring to the modified circuit diagram (Fig. 12) it can be seen that when contact I85 is opened, it initiates the start impulse. The initiating of the start impulse by the contact I85 permits the contact I I If to be opened later in the cycle but, of course, prior to the transmission of the first selecting impulse.

It is obvious, of course, that various other modifications of the apparatus and circuits shown and described herein may be made without departing from the spirit or essential attributes of the invention and it is desired, therefore, that only such limitations shall be placed thereon as are imposed by the prior art or are specifically set forth in the appended claims.

What is claimed is:

1. In a keyboard transmitter, a rotatable sleeve member, a plurality of key levers, a plurality of code bars operative to various combinations of settings by said key levers, a plurality of rockable members individual to each of said code bars and operated in accordance with the position of said code bars, a set of transmitting contacts, a set of contact operating members, a set of associated actuators for said contact operating members operable by said rotatable sleeve member, and means whereby said contact operating members are selectively operated by said associated actuators to operate said contacts in accordance with the positions of said rockable members.

2. In keyboard transmitting apparatus for telegraphs employing a definite interval startstop code, a set of selecting bars, a set of transmitting contacts and a rest contact, a distributor mechanism normally actuating said rest contact to transmit a rest impulse and adapted upon the movement of said distributor mechanism from a normal position to invariably transmit a start impulse and thereafter cooperating with means controlled by said selecting bars to selectively actuate said transmitting contacts to transmit impulses corresponding to the settings of said selecting bars and invariably thereafter again actuate said rest contact to transmit another rest impulse, electrical means for initiating the operation of said distributor mechanism andmeans for bringing said distributor mechanism to normal condition after each operation thereof.

3. In a permutation keyboard for telegraphs and the like, a set of transmitting contacts, a set of contact operating members adapted to pivot about one of two points thereof, means for determining the pivot points of said contact operating members, and means for pivoting said contact operating members about determined pivot points to selectively actuate said contacts.

4. A permutation keyboard mechanism comprising a rotatable cam sleeve, a group of key levers, a set of selecting bars, a plurality of transmitting contacts, a plurality of contact operat ng members, means controlled by said selecting bars to variably condition said contact operating members for operation, and means operated by said rotatable cam sleeve for invariably actuating said contact operating members to variably operate said transmitting contacts.

5. In a telegraph transmitter, a group of key levers, a universal bar adapted to be operated by any one of said key levers, a rotatable distributor mechanism, means controlled by said universal bar to initiate the rotation of said distributor mechanism, means operated by said distributor mechanism to stop the rotation thereof at the end of one revolution and means controlled by said distributor mechanism and cooperating with said universal bar to prevent subsequent operation of a key lever during the rotation of said distributor mechanism.

6. In apparatus for telegraph systems employing signals separated by space intervals and each comprising a starting interval and a definite number of selecting intervals, a plurality of current controlling contacts, key levers, a plurality of permutation bars selectively responsive to actuated ones of said key levers, a plurality of contact controlling members, a plurality of members operable by said permutation bars cooperating with said contact controlling members, an independently. rotatable cam sleeve, a plurality of rockable members for selectively actuating said contacts in accordance with the position of said permutation bars, electrically controlled means for releasing for rotation said cam sleeve simultaneously with the positioning of said permutation bars and means for stopping said cam sleeve at the completion of one revolution.

'7. In a keyboard transmitter, a rotatable cam sleeve, a bank of key levers, a set of contacts selectively and indirectly operated by said cam sleeve to transmit code combinations of impulses, and electromagnetic means-controlled by said key levers to initiate the rotation of said cam sleeve and means operated by the above men mal condition after each operation thereof,

means operated by said electro-magnetic means toinitlateastartimpulsetoprecedeeachcombination of impulses and means operated .by said distributor mechanism to follow each combination of impulses with a rest impulse.

9. In a telegraph transmitter, an independently rotatable member, means for rotating said member, electromagnetic means for rendering said last named means operable to rotate said member, means for stopping the rotation of said rotatable member in a predetermined point in its rotation, a group of current controlling contacts, a series .of pivoted members, means operated by said rotatable member to sequentially actuate said series of pivoted members, and means operated by said pivoted members to selectively and sequentially operate said group of current controlling contacts.

10. In a telegraph transmitter, a rotatable member with a plurality of cams prearranged thereon, means'for rotating said member, means for rendering said last mentioned means operable, means for invariably stopping the rotation of said member alter one revolution thereof, a plurality of rockable members, means operable by said cams to sequentially actuate said -roclrable members, a set of current controlling contacts and means operated by said rockable members whereby said set of current controlling contacts are selectively and sequentially operated in combinations according to the code combinations of impulses to be transmitted.

11. In a telegraph transmitter for transmitting code combinations of impulses, a group of members having two varieties of motion but normally restrained from motion, a transmitting contact individual to each member of said group, means operative to actuate said members in successive order and solely mechanically operated means to restrain the movement of said members in one variety of motion and thereby compel the movement of said members in the other variety of motion in combinations according to the signal to be transmitted.

12. In a keyboard transmitter, a set of key levers, an independently rotatable member, a set of current controlling contacts, a series of contact levers having two varieties of motion, means operable by said rotatable member to sequentially actuate said contact levers in one variety of motion and means controlled by the actuation of one of said key levers to restrain the movement of said contact levers in said first variety of motion and to compel the movement thereof in a second variety of motion whereby said contacts are actuated in combinations corresponding to the actuated key lever.

13. A telegraph transmitter comprising a rotatable cam sleeve, a series of variably operable current controlling'contacts, an associated series of elements having two varieties of motion but normally restrained from motion by two unequal nations according to the signal to be transmitted.

14. In a telegraph signaling mechanism for transmitting telegraphic code impulses of the start-stop variety, a series of key levers, an independently rotatable member for controlling the transmission of said code impulses, means for limiting the operation of said key levers, an elec tro-magnetic mechanism, means controlled by the operation of anyone of said key levers to tatable member jointly with the initiating of a start impulse, means for rendering said electromagnetic means nonoperative during the rotation of said rotatable member and means whereby said electro-magnetic controlled means invariably stops the rotatlon of said rotatable member after one cycle thereof.

15. In a signaling transmitter, an independently rotatable distributor, means operable by said distributor to transmit combinations of a definite number of line condition impulses, means independent of said distributor to invariably initiate, prior to the transmission of said combinations of line conditions, the transmission of an impulse of uniform line condition and means operable by said distributor to terminate said impulse of uniform line condition.

16. In a signaling transmitter, a rotatable distributor mechanism, means operable by said distributor mechanism to transmit code combinations of impulses, and means independent of said distributor mechanism to invariably precede each combination of impulses with an impulse of uniform condition.

17. In apparatus for telegraph systems employing a definite interval code, a group of transmit- 18. In a telegraph mechanism for transmitting combinations of a definite number of impulses preceded by a starting impulse and followed by a resting impulse, a setof transmitting contacts equal in number to the impulses in said combinations, 9. rest contact, a start contact in series with said rest contact, a rotatable member cooperating with means to selectively control said transmitting contacts, means for releasing said rotatable member, means cooperating with said start contact to invariably transmit a start impulse, means operable by said rotatable member whereby said start contact is normally positioned and means for invariably operating said rest contact to transmit a rest impulse after ac- .tuation of said transmitting contacts.

19. In a. telegraph transmitter for transmitting combinations of a definite number of impulses separated by space impulses and preceded by starting impulses, a set of current controlling contacts, an associated set of controllers therefor, an independently rotatable member, means cooperating with said rotatable member and said contact controllers to selectively and sequentially control said contacts, a start magnet forinitiating the rotation of said rotatablemember and means operable directly by said start magnet to transmit said starting impulse.

20. In a telegraph transmitter, an independently rotatable distributor mechanism, a magnet for controlling the rotation of said distributor mechanism, a first contact adapted to render said magnet energized whereby said distributor mechanism is released for rotation, means for actuating said first contact, a second contact, means controlled=by said magnet after the release of said distributor mechanism whereby said second contact is actuated to interrupt the circuit to said magnet whereupon said magnet controlled means is conditioned to stop the rotation of said distributor mechanism after one cycle thereof and means operable after a predetermined amount of rotation of said distributor mechanism to render said first contact actuating means unoperable during the remainder of the cycle of operation of said distributor mechanism.

21. In a keyboard transmitter, a distributor mechanism, magnetic means for controlling said distributor mechanism, a set of key levers, a universal bar operable by said key levers, a contact for controlling said magnetic means, means carried by said universal bar to operate said contact and means operable by said distributor mechanism for rendering said contact operating means unoperable during the operation of said distributor mechanism.

22. A keyboard transmitter comprising an independently rotatable member, a bank of key levers, a universal bar operable on the actuation of any one of said key levers, magnetically operated means for initiating and stopping the rotation of said rotatable member, a contact for controlling said magnetic means, a contact operating member carried by said universal bar, means operable when said rotatable member is normally positioned whereby said contact operating member is adapted to actuate said contact to initiate the rotation of said rotatable member, and means operable by said last mentioned means whereby said contact operating member is rendered unoperative with respect to said contact during the rotation of said rotatable member whereupon said magnetic means is rendered operable to stop the rotation of said rotatable member at a predetermined point in its rotation.

23. In apparatus for telegraph systems employing a definite interval code, a group of transmitting contacts, a set of key levers, a rotatable member, means cooperating with said rotatable member to selectively and sequentially actuate said contacts to transmit combinations of impulses according to the actuated key lever, means to concomitantly release said rotatable member and initiate a start impulse prior to the operation of said contacts, means operable by said rotatable member to terminate said start impulse and other means operable by said rotatable member to invariably transmit a rest impulse following the transmission of said combination of ROBERT F. DIRKES. GEORGE I. ROBERTS.

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