US2028508A - Ciphering apparatus - Google Patents

Description

Jan. 21, 1936. n-

CIPHERING APPARATUS S Sheets-Sheet 1 Filed Aug. '7, 1931 FIG. I

T T R Y H! m W R E E 0 v K T m T H A a Jan. P H|TT CIPHERING APPARATUS Filed Aug. '7, 1931 3 Sheets-Sheet 2 was FIG. 2

FIG. 3

INVENTOR PARKER HITT ATTORNEY Jan. 21, 1936. P Hm 2,028,508

CIPHERING APPARATUS Filed Aug. 7, 1931 3 Sheets-Sheet 3 INVENTOR PARKER HITT ATTORN EY Patented Jan. 21, 19.36

2,028,508 'cirnsamo Armm'ms Parker Hitt, New York, N. Y., assignor to International Communications Laboratories, Inc., New York, N. Y., a corporation of New York Application August 7, 1931, Serial No. 555,649

15 Claims.

This invention relates to cipher apparatus and more especially to cipher typewriters.

As the art ofcommunicating systems has developed, there has been an increasing tendency to employ cipher and code to render communi-' cations unintelligible to unauthorized persons during transmission. It is also desirable in employing cipher or code, to write in spaced groups of five or ten letters each, because of the reduced rates charged for transmitting this type of communication. Cipher writing offers several advantages over code writing in that a person may express himself directly in cipher while in code he is limited to the meaning of the code words available. The coding and decoding of a communication consumes a great amount of time, if a relatively complete code is employed, and if a brief or simple code is used, it is difiicult to express the exact meaning desired. A mistake in one letter of a code word will vary the meaning of or render meaningless several words of a message, while a mistake in one letter of a cipher word or group will result in a mistake of only one letter of a word in the received communication.

According to one aspect, the invention, as embodied in a ciphering typewriter, may be said to comprise a selecting mechanism, a plurality of reversing means adapted to co-operate therewith to modify the action of the selecting mechanism in such a way that its operation becomes that of a ciphering device, and a mixer or, cipher controller comprising a plurality of gear operated cams for controlling the operation of the reversing means during ciphering operations in accordance with a desired code.

By means of a cipher typewriter constructed in accordance with the present'invention, a communication maybe typewritten in cipher and after its transmission by any convenient means may be deciphered by a second cipher typewriter constructed and adjusted in the same manner as is the first cipher typewriter.

One feature of this invention resides in an arrangement for typewriting a communication wind a spring motor, which is employed to drive a cipher controller or mixer, embodied in the apparatus constructed in accordance with this invention. I

Another feature isto provide a cipher type- 5 writer of 'the'portable type which is compact, light, economical to construct and efficient in its operation.

Other features and advantages will become apparent from the following description, taken 10 in connection with the accompanying drawings wherein one embodiment of the invention is illustrated.

In the drawings:

Figure 1 is .a diagrammatic view, in perspec- 15 tive, of the arrangement of selecting and ciphering mechanism, cipher controller or mixer mechanism, and reversing means, embodied in a ciphertypewriter constructed in accordance with this invention;

Figure 2 is a detail, in elevation, of operating and holding bail mechanism included in the selecting and ciphering mechanism shown in Figure 1 and a ratchet drive device for the mixer or cipher" controller mechanism also shown in 25 Figure 1;

Figures 3 and 4 are details, in elevation, of a modified form of operating mechanism for the operating bail mechanism illustrated in Figure 2;

Figure 5 is perspective of a spring motor for driving the bail operating mechanism shown in Figures 3 and 4;

Figure 6 is an end elevation of a portion of a typewriter carriage feeding mechanism and parts associated therewith; and

Figure 7 is a detail, in plan, of a part shown in Figure 6.

Fig. 8 shows the rack and pinion of Fig. 6 in close mesh.

Fig. 9 shows the rack and pinion of Fig. 6 partially disengaged.

Referring to Figure 1, five pairs of permutation bars, designated ID to ID inclusive from front to rear, are shown positioned in a plane below a key 20, representative of all the keys of a typewriter; but one key 20, pivoted on shaft 29, being shown for the sake of clearness of illustration. One end of each of these permutation bars is biased against a stop 2| by springs 22 and the 5 bars are notched according to any desired code with the peculiarity that the notching on one bar is complementary to that on the other bar of a pair. Two forms of notches 23 and 24 are cut in the bars, notches 23 being square cut to receive the keys 26 without causing movement of the bar in which it cut, and notches 24 being bevelled as at 25, on the side away from stop 2|, so that a key 26 pressed down on a bevel will move the bar containing notch 24 away from stop 2| and square-cut as at 23 to receive the keys 28 without causing movement of the respective bars. Thus, if the key 20 is depressed, bar III will not move and bar II will move away from stop 2|. The depression of any key 20 will cause five of the ten permutation bars to move away from stop 2| and the other complementary five will definitely remain against stop 2|. 1

Above the set of permutation bars, just described, is a second set of five permutation bars 26 each bar of the second set being arranged above the center of a pair of complementary bars of the first set. The bars 26 each have one end similarly biased against a stop 21 by springs 28. On the opposite end of each bar 26 is pivoted at 3| a swinging lever or gate 30 which depends in position to co-operate in front of one bar or the other of a complementary pair of the lower permutation bars, as for example, l6 and H, or,

, l8 and I9. Thesegates 30 are positioned in front of the ends of the lower permutation bars by levers 32, the rearmost lever 32 only being shown rotated against the pressure of spring 40, if lever 36 is rotated in the direction shown by arrow 4|. The position of lever 36 is determined by the position of a pin 42 engaged in a slot 43 formed in the end of lever 36 opposite the point 31. Pin 42 is mounted on a triangular plate 44 and at the other two points of the triangle, the upper ends 45 and 46 of levers 41 and 49 project through plate 44. The levers 41 and 49 are pivoted on a shaft 56 and each lever has a projection 52 extending laterally therefrom and bearing against the periphery of one of a pair of notched wheels or cams 54 and 55 mounted on a shaft 60 to rotate freely thereon. The projections 5| and 52 are urged into engagement with the notched wheels by tension springs 53 engaging the lower end of each lever 41, 49.

If the projection 5| is engaged in a notch in cam 54 and projection 52 is not engaged in a notch in cam 55,v then the triangular plate 44 will take up such a position that pin 42 is deflected in the direction of arrow 56, moving lever 36 with it and placing the point 31 in the position shown in Figure 1 with reference to the cam 35.

If projection 52 is in a notch in cam 55 and projection 5| is not in a notch in cam 54, then the triangular plate 44 will be so moved that pin 42 will be deflected in the direction of arrow 4| and the lever 36 will be thrown over with it so that point 31 rests on the other side of the cain surface 35 and the position of lever 32 will not be changed. If, on the other hand, projections 5| and 52 both rest in notches in the cams 54 and 55, then the triangular plate 44 will be moved, by the action of springs 53, so that pin 42 will be deflected in the direction of arrow 51 and, similarly, if projections 5| and 52 are both out of notches on cams 54 and 55, then the triangular plate 44 will be moved, against the action of springs 53, so that the pin 42 will be deflected in the direction of arrow 58. In either of the last two cases, lever 36 will be so moved that the projection 31 will rest on the point of projection 35 and will force the lever 32 over, against the action of spring 46, so that the lower end, designated 39, of the rear gate 36 will then rest in front of permutation bar 8 instead of in front of permutation bar I9. Since one or the other of these permutation bars will be moved upon the depression of any key 20, and since the positions of gates 36 are determined by the notching of the cams 54 and 55, it will be seen that the upper permutation bars 26 will be moved or not moved according to conditions determined jointly and independently by the choice of the key 29 to be depressed and by the notching on the cams 54 and '55.

Permutation bars 26 are differentially notched according to the selected code so that the notches therein, designated 6|, correspond with the notches 23 and 24 of the even-numbered lower permutation bars. For any given position of permutation bars 26, one line of notches 6| is setup so that a seeker 62 can enter the aligned notches under the bias of a spring 63.

Reference may now be had to Figure 2. When the permutation bars 26 are lined up, a Single seeker 62'is in a position to enter the aligned notches in these'bars, .but each of the seekers is held down by a holding bail 64, which is pivoted at 65 and is held in the position shown by the operating bail 66 for a purpose and in a manner to be described later. .Each seeker 62 has on its lower end a hook 61 and is pivoted on bar 68 at 69. The spring 63 tends to throw the seeker up into the notches, unless the bail 64 holds it out. When a seeker goes up into the ,notches, a hook 61 engages a bar 18 which is a part of the operating bail, 66. Bar 68 is held in the position shown by a spring 1| and its pivot 12,-and is connected by a suitable linkage 13 to a type bar 14 so that, when bar 68 is depressed, a type bar 14 will strike against a platen, not shown. The operating bail 66 is pivoted to two bars 15 which carry between them a universal bar 16 which is held in the position shown by a spring 11. This universal bar 16 goes under all of the keys 20 so that when any one of them is depressed, the operating bail 66 is pulled down against the pressure of the spring 11. As the bail is pulled down, one of the seekers- 62 will be in a position to ride into a line of notches 6| in permutation bars 26, since the holding bail 64 will turn about pivot 65 when the pressure of the operating bail 66 is removed from it. When a seeker 62 is caused to enter a line of notches through the'pull of its associated spring 63, the hook 61 will engage with bar on ball 66 and the bar 68 will be pulled down, causing the type bar 14 to be operated through linkage 13 and a letter to be recorded on a sheet of paper carried by the typewriter carriage, not shown. The depression of any key 26 also causes a lever 18 to be rotated in a clockwise direction about its pivot 80, which in turn causes the rotation of a lever 8| in a counter-clockwise direction about its pivot 82 and against the pull of a spring 83. A pawl 84 will then be lifted up and engage the next adjacent tooth of a ratchet 85. When any key 26 is released the universal bar 16 will follow it under the action of spring 11 jointly with spring 83, the latter causing the pawl 64 to move the ratchet 85 through one tooth. This ratchet wheel 85 is (Fig. 1) are attached and constitutes the common drive for the notched cams 54 and 55 and similar cams controlling the motion of. the other lever arms 32.

A modified form of mechanism for moving the operating bail 66 is illustrated in Figures 3 and I 4, wherein the operation of any key 20 is shown as moving down a universal bar 81; which, in turn, releases a latch 88 so that a shaft 90 can rotate in the direction of the arrow. A spring 9I will cause the latch 88 to engage a detent 94 on shaft 99, after one revolution of said shaft, since a fiat spring 92 carried by the universal bar 81 will have slipped down over the point of latch 88 and will not engage with this latch until said universal bar has again reached its full upward position. The single rotation of shaft 90 causes a downward and an upward pull of the operating bail 66 by means of a cam eccentric 93 fastened to shaft 90, the cam being held between two rollers 95 and 96 mounted in the bars at the top and bottom of the cam 93. During the first half of the revolution of shaft 90, cam 93 will press,downwardly on roller 96 and pull the bail 66 in a downward direction. During the second half of the revolution of shaft 90 the cam 93 will bear against the upper roller 95 and will lift the bail 66 up to its initial position. Shaft 90 may be driven by spring motor or by an electric or other continuously driven motor and suitable clutch mechanism. I

A preferred type of spring motor is shown in Figure 5 wherein 91 is the carriage of a typewriter which carries the platen 96. Against this carriage, bears a lever I00, which rotates about a bearing IN. This lever is tonnected to one end of a shaft I02 upon the other of which is fixed a segmental rack I03 provided with gear teeth I04 which engage with a pinion I05 integral with a ratchet I06. Around the shaft I02 there is coiled a spiral spring I01 which tends to keep the lever I in the position shown. A gear wheel I08, mounted on the same shaft with pinion I and ratchet I06 so as to rotate freely relative thereto, bears on its surface a pawl IIO which engages the ratchet I06 so that the pressure of spring I01 gives gear I08 a tendency to turn in the direction shown by the arrow. Gear I08 engages with a pinion II2 which is fixed to the same shaft with a gear 3. Gear II3 engages in a right angle relation with a gear II 4 which is mounted on shaft 90, above described. With reference to the action of the spring motor, the carriage 9'! is illustrated in Figure 5 as being at its extreme right-hand (looking at the rear of the platen) position in which a line of writing has just been completed. The operator, in normal operation of the typewriter, must cause the paper to be shifted one or more lines and manually return the carriage to the initial or starting position. In so doing the lever I00 will be swung through a distance of about 6 inches against the tension of the spring I01 causing the rack I03 to turn the pinion I05 and ratchet I06. The pawl IIO will yield and the wheel I08 will remain in position. As soon as the operator has completed the return of the carriage, the full pressure of the spring I01 will be transmitted from ratchet I06 through pawls H0 and III to gear I08 and thence 'to shaft 90, which then is in a position to operate, as shown in Figures 3 and 4.

It is the accepted practice among communication companies to designate as a cipher message a group or groups of unpronounceable characters. A charge ismade for the maximum combination of ten successive characters as a word. However, at a recent conference in Madrid this maximum combination was reduced to five characters and such change will be effective in 1934. It is desirable, therefore, when writing cipher with this machine, to have the cipher in groups of five or ten letters without requiring the operator to so space said groups;

To attain this end, means shown in Figures 6, 7, 8, and 9 are provided. The platen 98 on the carriage 91 of a typewriter is of well-known form. The movement of this carriage is controlled by a rack I I5 pivoted at I25 and held by a spring II6 against a stop I" on the carriage 91 so that its teeth engage in close mesh with the teeth of a pinion II8 mounted on the same shaft with the carriage driving ratchet wheel I20. Lever I25A, a projection of the rack H5, is used to completely disengage manually the rack from the pinion. This mechanism is a well-known driving and spacing mechanism used on typewriters. To cause the carriage to space automatically in five letter groups, the rack I I5 has been cut away, as illustrated in Figure '7, so as to leave groups of four teeth separated by spaces where there had been two teeth. For ten letter groups, nine teeth would be separated by spaces where two teeth had been cut away. A lever I22, pivoted at I23 and having a roller I 2I at its upper end, serves to partially disengage the rack I I5 as it turns about pivot I 25, so that the teeth of the rack and pinion will be in loose mesh and the carriage to which the rack is attached will automatically jump through one space whenever a spacing of the rack arrives at the pinion II8, the lever 22 being held in key-depressed position at this time by a key I24. Since the partial disengagement of the rack I I 5 from the pinion I I8 has to be rather definite in amount, an adjustment screw I26 is provided to hold pivoted lever I3I in position, and a latch I21 holds thelever I22 against an adjustable stop screw I32 for such time as the five letter grouping is desired.

Referring now to Figs. 8 and 9, a detailed description of the co-operation of rack H5 and pinion II8 when the machine is writing either plain text or cipher will now be given.

When the lever I22 is not depressed the rack and pinion are in close mesh (Fig. 8) and the machine will space in anormal manner for plain text, that is, the rack will advance one tooth for each depression of a lever 20 or the spacing bar (not shown)--. Tension is supplied to the rack II5 by a spring (not shown) in the direction of the arrow and it is held in position by the teeth of the pinion II8. This pinion is of such diameter that four teeth of the rack normally engage four teeth of the pinion. Thus, it can readily be seen that the removal of two teeth, such as C and D, fromthe rack will in no way aflect its regular movement since teeth B and E will still be in mesh with teeth H and L of the pinion.

When lever I22 is depressed, the rack and pinion are partially disengaged and the machine will now space in groups 'of five or ten characters according to the construction of the rack, as previously described. Fig. 9 shows a rack I I5 designed to allow the machine to print in groups of five characters which results in a cipher mes-' sage suitable for transmission by a communication company. The pinion is now spaced away from the rack such a distance as provided for by the adjustment of lever I 3| and stop screws I 32 and I26 (Fig. 6), so that only two teeth of one engage two teeth of the other. In the position shown it is assumed that three characters have already been printed and teeth E and F of the rack will now be held by teeth J and K of the pinion.

After the fourth character is printed the rack is allowed to advance one tooth and will then be held only by tooth J of the pinion in contact with tooth E of the rack. Since there are no teeth on the rack atpoints M and N tooth H of the pinion merely enters the space between teeth B and E of the rack.

After the fifth character is printed, the pinion H8 turns about its axis a distance sufficient to allow the rack to space one tooth. In so doing tooth J of the pinion moves to the position designated L in the drawings, where it is no longer holding the rack. Consequently, the rack moves to the right until tooth 13 comes in contact with tooth O of the pinion which is now in the position designated J on the drawings.

When the sixth character is printed it will be in a position corresponding, to point M on the rack, and, since the last was printed at a point corresponding to tooth E, it can readily be seen that after the fifth character is printed, the machine automatically allows the rack H5 carrying the platen 98 to space. a

If there are thirty-two keys 2B and thirty-two type bars M, and all the gate levers are held so that they engage the even numbered lower per- 'mutation bars, then the notching in the upper and lower permutation bars is such that if a key A is depressed then the seeker 62, connected by linkage to the type bar A, will find that the notches 6B are so lined up that it and it alone could enter the notches, whereupon the ball 66 will cause the letter A to be printed. This is the normal operation of the selecting mechanism whereby the depression of any keycauses theoperation of its own type bar. However, if the gates 30 are free to take up a position in front of either an oddnumbered or an even-numbered lower permutation bar, depending upon the notching of the cams E i and 55, then it will be evident that the depression of a key A, for example, will also certainly find one or more of the gates 30 in such a position that they will bear against an oddnumbered lower permutation bar, in which event the upper permutation bars 28 will be so lined up that a seeker, other than that connected by linkage to type bar A, will find its way into the lined up notches-6i, whereupon the bail 66 will cause this other letter. to be printed. Thus, the normal operation of the selecting mechanism is modified and oiphering effected.

The action of the notched cams 56 and 55 and the method of'setting them is fully described in United States Patent No 1,848,291, granted to the present applicant March 8, 1932, for a ciphering and deciphering apparatus, said application being assigned to the same assignee as is the pres ent application. Briefly, the means for operating the notched cams 5d and 55 comprise a gear 928 fixed to each of these cams, the gears being operated by a common pinion fixed; to the shaft 86, or a number of equally sized gears 830, each having the same number of teeth, fixed to said shaft 86 and individually co-operating to drive the gears fixed to the notched cams St or 55 and to the other cams employed to actuate the reversing means for operating the other gate levers 30. The gear I28, fixed to one of the notched cams 56 and 55, has a number of teeth different from the number on any one of the other similar'gears. Since there are ten of these gears fixed to the five pairs of notched cams and since each of these gears has a difierent number of teeth, this mechanism will variably drive themeans for 'reversingthe gate levers 30. It is to be noted, however, that the notches cut in cams 56 and 55 are so arranged relative to the teeth of the gears I28, fixed to these cams, that the projections 5i and 52 are either definitely in, ordefinitely out, of the notches in these cams at the completion of each step of rotation of the shaft 86 by the mechanism shown in Figure 2. It is also to be noted that the gears 528 may be dis-engaged from the gears I30 so that the gears H28 and the cams 54! and 55, fixed thereto, may

be manually rotated to the desired adjusted positions to set or adjust the cams according to some prearranged keyword or arrangement of characters. Such a device is shown and described in U. S. Patent 1,848,291, supra, wherein the gears 2, attached to the shaft 8 co-operating with gears i5 and cam 51, correspond to gears H30, attached to shaft 86 co-operating with gears I28 and cams 56 and/or 55 of the present application. When deciphering a message, the cams of the cipher controller of the deciphering apparatus must be set or adjusted to the same positions as those of theciphering apparatus.

As many changes could be made in the above described arrangements and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that 'all matter contained in the above description, or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a oiphering apparatus, a set of permutation bars arranged in pairs, a second set of permutation bars, means associated with each bar of said second set and adapted to co-operate with one bar or the other of each pair of bars of said first set, reversing means for-controlling the operation of said first named means and means for variably operating said reversing means.

2. In a cipheringapparatus, a selecting device having a set of permutation bars arranged in pairs, a second set of permutation bars, means for moving one bar of each pair of said firstnamed permutation bars, the combination of reversing means, means for variably operating said reversing means, and means responsive to the operation of said reversing means for determining which bars of said second-named set of permutation bars will move upon movement of one bar of each pair of said first-named set.

3. In a ciphering typewriter, a set of notched permutation bars arranged in pairs, keys adapted to co-operate with said bars to move longitudinally one or the other of the bars of each pair, a

. movement of one bar of each pair of lower bars will move or not move" bars of the second set according to the position of said gates, reversing means for controlling the position of the gates in front of one bar or the other of each pair of bars 1 of said first set, and means for variably operating said reversing means.

4. In a oiphering apparatus, a selecting device having a plurality of movable selecting elements, means for moving certain of said movable semeans for variably operating said reversing means, a second set of movable selecting elements', means responsive to'the movement of said reversing means to cause said certain movable selecting elements to move selected ones of said second set of selecting elements, andmeans responsive to the movement of said first-named means for intermittently rotating the means for variably operating said reversing means.

5. In a ciphering apparatus, a plurality of keys, a selecting device. having a first and a second set of selectingelements, a plurality of reversing means, means for variably operating said reversing means, any one of said keys being adapted to move predetermined elements of the first set, and means responsive to said reversing means for determining which of the elements of the second set will be moved by the selected elements of the first set moved upon the operation of any key.

6. In a ciphering' device, a selecting device having a firstand a secondflset of inov'able selecting elements, mechanicalyreversing means comprising a shif table membergrneans comprising cams and gears for variably's'hifting said mem her, and means responsive ,to'the 'shifting of said member for determiningfwhich of the elements of the second'set-will move upon movement of certain of the elements" of the flrs t-Tset;

7. In a ciphering' devicl-"a "'selectin 1 having afirst {and a second setof; movable selecting elements, mechanical reversing Sineans comprising a g 'movable plate having afpin projecting therefrom, means comprising eams" and gears for variably movingsaidgpl'ate'to shift said pin in four directions, and means responsive to the shiftingo'f said pin for' determining which of the elements of the second set will move upon,

movement of certain eleinents of the first set.

8. In a ciphering typewriter, the combination of a plurality of keys, a plurality of pairs of longitudinally'movablepermutation bars engageable by said keys, a plurality of type bars, and. a selecting device comprising a plurality of selecting elements, a gate connected to each selecting element and having a portion movable into and out of the path of one or the other of the corresponding pair of permutation members, means co-operating with said selecting elements to cause the operation of a type bar upon the operation of its own key, a reversing means forcontrolling the position of said gates whereby upon operation of a key the permutation bars co-operate with the positioned gates to modify the operation of the selecting elements and said first-mentionedmeans causing theoperation of a type bar not corresponding to the operated key, and means for variably operating said reversing means.

9. In a ciphering typewriter, a set of permutation bars notched according to a selected code and arranged in pairs, the notching of one bar being complementary to that of the other bar of a pair, keys adapted to co-operate with the notches of said bars to move longitudinally one or the other of the bars of each pair, a second set of permutation bars, one for each pair of the first permutation set, difierentially notched according to the selected code and each normally coupled to one of the respective pairs so as to to the operation of said reversing means for determining which bars of said second-named set of permutation bars will move upon movement of onebar of each pair of said first-named set to cause the alignment of notches in the bars of said second-named set for the reception of a seeker associated with a type bar correspondin to a key other than the key operated. 10. In a typewriter, the combination of a plurality of type bars, a plurality of keys, a set of permutation bars settable by said keys, a type bar operating lever connected to each type bar and pivotally mounted at one end, a seeker pivotally connected to each type bar operating lever and controlled by a setting of said permutation bars, a pull bar operated by any one of the keys, means normally preventing engagement of said seekers with the permutation bars, means responsive to movement of the pull bar to free the seekers for cooperation with the permutation bars ,so that the latter may select the seeker of the type bar to be actuated, and means carried by each selected seeker and moved thereby into engagement with the pull bar during movement thereof to couple the pull bar to the type bar operating lever connected to said cooperating seeker whereby further, movement of the pull bar actuates the type bar.

11. In a typewriter, the combination of a plurality of type bars, a plurality of keys, a set of permutation bars settable by said keys, a type bar operating lever connected to each type bar and pivotally mounted at one end, a seeker pivotally connected to each type bar operating lever, means normally engaging each seeker for holding it out of operative relation with the permutation bars, a pull bar operated by any one of said keys, means controlled by movement of the pull bar for rendering the holding means inefiective, means operating when said holding means is rendered ineffective to move the seekers into operative relation with the set of permutation bars so that the latter may select the seeker of the type bar to be actuated, and means controlled by the selected seeker and moved thereby into engagement with the pull bar after a predetermined movement of the latter to couple said pull bar to the type bar operating lever of the type bar corresponding to the selected seeker whereby further movement of said lever actuates the type bar.

12. In a typewriter, the combination of a phirality of type bars, a plurality of keys, a set of permutation bars settable by said keys, a type bar operating lever connected to each type bar and pull bar operated by any one of the keys, means normally preventing engagement of said seekers with the permutation bars, means rendered effective during a predetermined movement of said pull bar to free the seekers for cooperation with the permutation bars so that the latter may select the seeker of the type bar to be actuated, and means connected to each selected seeker and moved thereby into engagement with the pull bar after said predetermined movement of the latter for coupling the pull bar to the type bar operating lever corresponding to said cooperating seeker whereby further movement of the pull bar actuates the type bar.

13. In a typewriter, the combination of a plurality of type bars, a plurality of keys, a set of permutation bars settable by said keys, a type bar operating lever connected to each type bar and pivotally mounted at one end, a seeker pivotally connected to each type bar operating lever and controlled by the permutation bars when set, a pull bar operated by any one of the keys, means operating under control of the pull bar to move the seekers into operative relation with the set of permutation bars so that the latter may select the seeker of the type bar to be operated, and an individual arm provided with a hook connected to each seeker, said hook being moved by the selected seeker into engagement with the pull bar after a predetermined movement of said bar to couple the pull bar and type bar operating lever whereby further movement of the pull bar actuates the type bar corresponding to the selected seeker.

14. In a typewriter, the combination of a plurality of type bars, a plurality of keys, a set of permutation bars settable by said keys, a type bar operating lever connected to each type bar and pivotally mounted at one end, a seeker pivotally connected to each type bar operating lever and controlled by the permutation bars when set, a pull bar operated by any one of the keys, a coupling link provided with a hook. pivotally mounted on each type bar operating lever'and connected to the seeker individual thereto, and means effective upon movement of the pull bar to move the seekers into operative relation with the set of permutation bars so that the latter may select the seeker of the type bar to be operated, said hook being moved by the selected seeker into engagement with the pull bar after a predetermined movement of the latter whereby further movement of said pull bar actuates the type bar corresponding to the selected seeker.

15. In a typewriter, the combination according to claim 14 wherein said means comprises a. coiled spring connected at opposite ends to the type bar operating lever and to the seeker pivotally mounted thereon.

PARKER HITT.

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