US2089666A - Step movement mechanism for typewriters and the like - Google Patents

Description

w. c. ROE 2,089,666

STEP MOVEMENT MECKHANISM FOR TYPEWRITERS AND THE LIKE Aug. 10, 1937.

3 sheets-sheet 1 Original Filed Feb. 5, 1952 gas INVENTOR.

ATTORNEY.

Aug. 10, 1937. w. c. ROE 2,089,655

STEP MOVEMENT MECHANISM FOR TYPEWRITERVS AND THE LIKE Original Filed Feb. 5, 1932 5 Sheets--Sheeil 2 INVENTOR.

M'/mm. C. oe.

BY 5W@ @M ATTORNEY.

W. C. ROE

Aug. 10, 1937.

STEP MOVEMENT MECHANISM FOR TYPEWRITERS AND THE LIKE Original Filed Feb. 5, 1932 INVENTOR, h/i//zam C P06.

ATTORNEY.

Patented Aug. 10, 1937 vUNITED STATES PATENT OFFICE STEP MOVEMENT MECHANISM FOR TYPE- WRITERS AND THE LIKE William C. Roe, Elyria,

Ohio, assignor, by

mesne assignments, to Printel Communication Systems, Inc., New York, N. Y., a corporation of New York 13 Claims.

selective current impulses; this class of apparatus being sometimes referred to as telegraphic typewriters.

The invention relates more particularly to elec- H, trically controlled mechanisms of the step movement class for effecting a step by step positioning movement of the type cylinder or other corresponding element of the receiver.

This application is divisional from my appli- 1:, cation Serial No. 591,224 led February 5, 1932,

patented Feb. 19, 1935, No..1,991,416, for improvements in Receivers for the electrical transmission of intelligence. In that application is illustrated and described a complete receiver of the class above referred to and an velectrical system for controlling the same and reference may be had thereto for a complete description of parts of the system and apparatus herein more briefly described or referred to.

It is an object of the present invention to provide an improved apparatus of the kind referred to in which transmitted electrical impulses may actuate a letter printing `type selective apparatus whereby, in an improved manner, to translate the impulses into letters and words.

Another object is to provide in a receiver of the class comprising a type cylinder or the like having a plurality of characters thereon and adapted to be selectively moved to position it selectively 35 with respect to the characters thereon, an improved positioning mechanism therefor responsive to a variety of predetermined electrical impulses transmitted thereto.

Another object is to provide in a receiver of 40 the class referred to, having a type cylinder or the like movable rotatively and axially' to position it selectively with respect to the characters thereon, an improved positioning mechanism therefor.

45 Another object is to provide an improved stepmovement mechanism.

Another object is to provide an improved stepmovement mechanism responsive to electrical impulses.

a Another object is to provide a step-movement mechanism for selectively positioning the type cylinder or the like of a telegraph typewriter or the like in response to the reception of electrical impulses or groups of impulses and in which, to

5,-, position the type cylinder, it may be moved rotatively or axially and in these directions separately or concurrently.

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention is fully disclosed in the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a view in some respects diagrammatic illustrating a part of an embodiment of my invention, whereby a type cylinder which I may employ may be selectively moved to printing position and returned to a normal position;

Fig. 2 is a fragmentary view taken from the plane 2 of Fig. 1;

Fig. 3 is a view taken from plane 3 of Fig. 2;

Fig. 4 is a view to an enlarged scale of a ratchet element which I may employ and illustrated in Fig. 1;

Fig. 5 is an elevational view with parts broken away for clearness, of an apparatus in which my invention may be embodied, and illustrating also in actual structural form, certain parts which. are illustrated diagrammatically in Fig. l;

Fig. 6 is a fragmentary view taken from the plane 6 of Fig. 5;

Fig. 'l is a top plan view of an actual embodiment of my invention, with parts broken away to simplify the drawings;

Fig. 8 is a fragmentary view taken from plane 8 of Fig. 'l and with parts omitted for simplicity;

Fig. 9 is a fragmentary view taken from plane 9 of Fig. 5, with the parts drawn to a smaller scale, approximately half of the scale of Fig. 5;

Fig. l0 is a fragmentary view taken from plane I0 of Fig. 5.

In general, the apparatus in which my invention is embodied comprises a type cylinder l, mounted for rotary movement on its axis and also for movement longitudinally of its rotary axis. The cylinder hasa cylindrical surface thereof divided up into preferably 42 divisions in each of which may be provided a type character, number or letter. By rotating the cylinder and/or moving it longitudinally, any one of the characters may be brought into position to be printed upon a strip of paper as will be more fully described or referred to hereinafter.

The mechanism to be fully described hereinafter for rotating and reciprocating the cylinder I, is actuated by electrical impulses transmitted to the apparatus from the remote or sending station. Preferably, the impulses are transmitted over two circuits, the impulses on one circuit functioning to rotate the type cylinder l, and those of the other functioning to move it longitudinally; and in either case, the apparatus responds to each single impulse to rotate the cylinder a single space or division or to move it longitudinally a single space or division.

In Fig. 1 I have illustrated in semi-diagrammatic form an apparatus embodying the general principles of my invention, and in the other iigures have illustrated the same mechanism but more as it actually appears in a preferred form when produce'd for practical or commercial purposes.

Referring to Fig. 1, I have reproduced at 1 and 8 two impulse receiving magnets, each having associated therewith an armature 35 and 38 pivotally supported at 31-31 one end of each being adapted to be attracted by the magnet and the other end of each having a finger 38-38 engaging an arm 38-38 of a pair of bell cranks "-48, pivoted at 4i-4|. The other arms 42-42 of the similar bell cranks 48-48, are bifurcated at their free ends to provide ngers,43-44, provided each at the free ends thereof with downwardly projecting pawls 45 and 48. These pawls straddle elongated longitudinally movable ratchet pieces 41-41 provided on their lateral edges with longitudinally extending rows of teeth 85 and l: respectively, engageable by the pawls 45 and 4 Extending downwardly from the ratchet pieces 41-41 are pins 81-81 engaged upon their rearward sides `by the upper free ends of springs 88-88, see Figs. 5 and 10. The springs 88 are preferably formed from nat steel strips supported and disposed to exert a forward resilient thrust on the pins 81, thrust portions 88-88 being provided on the upper free ends of the springs 88 and interposed between the springs and the pins 81, whereby, in all relative operative positions of the pins 81 and springs 88, the thrust of the spring may be transmitted from the upper extreme end of the spring.

'I'he lower ends of the springs 88 are rigidly connected as by screws 1l to a head 1| rotatably supported in ball bearings 12. but adapted, in a manner to be described, to take up a normal position such as that illustrated in Fig. 5, in which the springs 88 are bent to continuously exert a forward thrust on the pins 81 and the ratchet pieces 41.

In connection with the apparatus thus far described, when a magnet such as the magnet 1 is energized with one or more impulses, the armature 35 thereof will be rocked clockwise and correspondingly rock the bell crank 4I counterclockwise against the clockwise torque o1' a spring 15. The spring 18 normally maintains the pawl 4l against the teeth 85, and the pawl 48 out of engagement with the teeth 88, and the pieces 41 are continuously resiliently pruned forward by the springs 88 as above described. Therefore, upon energization of the magnet 1, say, by one impulse, the pawl 48 will be moved into engagement with a tooth 88 to transfer the ratchet piece holding function from the pawl 4l to pawl 48.

When the magnet 1 is de-energized at the end of the said impulse, the spring 15 returns the pawl 48 toward the teeth 85, but the rearwardly inclined edge, such as the edge 18, of the tooth 88, permits a slight forward movement of the ratchet piece 41 during the inward movement of the pawl 48 and outward movement of the pawl 48 so that during the return of the pawl 45 toward a small distance by the spring 88 so that the pawl 45ss it returns, engages the next sucend oi.' the link 48 ceeding tooth 85 and the ratchet piece 41 will thus be advanced a distance corresponding to one tooth space. Thus also, upon energizing the magnet 1 with a succession of impulses, the bell crank 4l will be vibrated back and forth, in one direction by the magnet i and in the other by the spring 15, and the ratchet piece 41 will be stepped forwardly rapidly a corresponding number of teeth or steps.

In the forward ends of the ratchet pieces 41 are provided upstanding pins 48 over which are looped links 48 and 58 having elongated slots 18 and 19 respectively therein. At the outer free is pivoted as at 5| the arm 52 of a bell crank 53 pivotally mounted at 54. A spring 55 constantly exerts a counter-clockwise torque on the bell crank 53. The other arm 63 of the bell crank has a head or pin portion disposed in the annular groove 8i of a shifting head 82 formed integrally with or connected to the type cylinder i, axially movable upon a supporting shaft 83 but splined or otherwise connected therewith to rotate with the shaft 83. The shaft 88 is supported in adjustable rotational bearings 84 and 85.

As will now be apparent, when the upper ratchet piece 41, as viewed in Fig. i, is stepped forwardly as above described, the pin 48 will advance in the slot 18 o1' the link 48 or tend to advance therein due to the exceedingly rapid forward movement of the pin 48 and due also to the stepped or intermittent character of its movement. At the same time, the spring 55 will rock the bell crank 53 counter-clockwise and move the type cylinder i along the shaft 83, the

extent of the movement being determined by the extent of movementvof the pin 48 which in turn is determined by the number of teeth or steps of advancement of the ratchet piece 41.

By means of the link and pin connections, 48-48, the intermittent movement of the ratchet piece 41 may go on freely unhampered by the inertia of the type cylinder and the parts connecting it with the ratchet teeth, and these latter parts may move with a steady or continuous movement, effected by an independent source of power, namely the spring 55. At the end of movement of the ratchet piece 41, whereat the end of the slot 18 engages the pin 48, the type cylinder i is accurately brought to rest at a position corresponding to the movement of the ratchet piece 41, which, in accordance with the selective number of impulses, positions the cylinder longitudinally with respect to a character thereon.

At the outer end of the link 58, a rack bar 55 is connected, and mounted to move longitudinally in unison with the link 58. A connecting rod 51 is pivotally connected to the rack bar 55 at 56 at one end and at the other end is pivoted as at 58 to a crank arm 59 pivotally supported at 80. A spring 8| continually exerts resilient torque clockwise on the arm 59 and thus, acting through the connecting rod 51, exerts a longitudinal resilient thrust toward the left as viewed in Fig. 5, on the rack bar 55'. The rack bar 55 has rack teeth 81 on the under side thereof meshed with the teeth of a gear 88 secured to the shaft 83 in any suitable manner and rotatable therewith.

As will now appear, when the ratchet piece 41, the lower one as viewed in Fig. 1, is projected for- Wardly with the intermittent rapid movement above described, the pin 48 thereof will advance in the slot 18. Concurrently therewith, the link 58 and rack bar 55'- will be pulled forwardly with a steady or continuous movement by the spring 5|,

thereby rotating the gear 88 and the shaft 83 'and the type cylinder I;` and the extent of rthe rotational movement of the type cylinder I will be determined by the extent of movement of the 5 l ratchet piece 41 and pin 48, the movement being finally stopped, after the ratchet piece 41 stops moving, by engagement of the end of the slot 19 with the pin 48; and the rapid intermittent movement of the ratchet piece 41 will not be interfered with by the relatively great inertia of the other parts mentioned, associated therewith, but the rotary movement of the type cylinder I will be accurately determined and will rotate the type cylinder I, one or more divisions thereof as described hereinbefore.

Since it is desired for 4each impulse In the magnets 1 and 8 to respectively rotate the type cylinder by an amount equal to one division thereof and to move it longitudinally an amount equal to one division, the pitch diameter of the gear 88 must be proportioned so that it will turn the type cylinder I one division for each tooth or each step movement of the corresponding ratchet piece 41;

and the ratio of the length of the bell crank arms 52 and 63 must be proportioned so that the longitudinal movement given to the type cylinder I will be correct for one complete division thereof for each tooth space or step of movement of the ratchet piece 41.

1" Where, as illustrated in Fig. 1, the longitudinal movement of the type cylinder I is in a direction at right angles to the longitudinal movement of the ratchet pieces 41, the bell crank arms 52 and B3 are preferably disposed at substantially 37 a right angle to each other and the pivot point 54 is preferably disposed so that the total movement of the bell crank arm will be substantially equal amounts on the opposite sides of corresponding center lines; for example, the bell crank arm 40 63 may move from one extreme position to the other, equal amounts on opposite sides of a horizontal line through the pivot 54, and the bell crank arm 53 correspondingly will move substantially equal amounts on opposite sides of vertical center line through the said pivot.

. By this provision, equal steps on the ratchet pieces 41 will effect equal steps on the type cylinder I. At the same time, the bell crank arm 63 may be longer than the bell crank arm 52 whereby any desired magnification of movement of the type cylinder I may be effected in correspondence to any suitable distance between the steps of the ratchet pieces 41. Again, if it be desired to move the type cylinder unequal amounts as, for example, where some of the characters may occupy more longitudinal length on the cylinder, correspondingly the teeth spaces on the ratchet pieces 41 may be variable. Furthermore, although the lever arm 52 moves around a supporting pivot 54 and therefore its angular movement for two steps adjacent the left-hand end of the ratchet piece 41 is greater than for successive teeth, nevertheless, by the arrangement of the lever arms above described, this is exactly compensated for in the movement of the type cylinder I; and for equally spaced teeth on the ratchet piece 41y the steps taken by the type cylinder I will be equal.

Referring again to Fig. 4, which illustrates one of the ratchet pieces 41 to an enlarged scale, I have shown the preferred form of the teeth 65 and 66. The teeth 65 comprise each a pawlengaging portion 65 disposed substantially at a right angle to the direction of movement of the ratchet piece 41 and a rearwardly inwardly inclined portion disposed at an angle of approximately 45 with the portion 65'. The teeth 66 comprises each a pawl-engaging portion 66', rearwardly outwardly inclined at an angle of approximately 30 from the direction of movement and a rearwardly inwardly inclined portion 66", at an angle of approximately 45, the shape of the teeth 85 and 68 thus provided being clearly illustrated in Fig. 4. I find that teeth of these forms cooperate more effectively and positively in conjunction with the pawls 45 and 46 respectively than other shapes, but as will be understood by those skilled in the art, the teeth 65 and 66 may be, in form, considerably varied from that illustrated in Fig. 4 without detracting unduly from a. positive accurate ratcheting function thereof.

The type cylinder I may be mounted on the shaft 83 to rotate and move axially thereon by various mechanical arrangements, but I prefer the construction illustrated in Figs. 1, 2 and 3. As illustrated in these figures, the type cylinder has longitudinal grooves between the longitudinally disposed series of character supporting portions. In one of these grooves is disposed a key 82' preferably in the form of a slender rod, an end of which is mounted slidably in a bore 8| in the head 82, and is secured at one end in a suitable recess in a flange 83' of the gear 88. The key 82' is thus rigidly connected to the gear 88, rotates with it and formsl a key or feather for guiding the longitudinal movements of the type cylinder I, and also serves as a means to rotate the type cylinder I to communicate thereto rotary or oscillatory movement of the gear 88.

By this construction, the key or feather 82' may be disposed at a relatively great radial distance from the shaft 83 to reduce to a negligible amount any tendency of the cylinder I to jam thereupon; and the type cylinder I may be relatively loosely mounted upon the shaft 83 and have a relatively loose engagement with the key 82 whereby the type cylinder may in every case move freely and with great rapidity to its selected position.

At I0 is an electro-magnet having an armature 89 pivotally supported at 90 and provided on its free end with an anti-friction wheel or roller 92 engaging an inclined portion 93 of a switch indicated generally at 94. The armature 89 is maintained in its counter-clockwise position against the tension of a spring 89 by the engagement therewith of one arm 9| of a bell crank 98 pivotally supported at 99. The other arm |00 of the bell crank carries, pivoted at its free end as at |04, an equalizing bar |05 bridging and engaging the pins 48.

The electric system and circuits by which the elements of the receiver herein described are operated, constitute no part of the present invention, that part of the invention being more fully described and illustrated in the above mentioned patent application, Serial No. 591,224. It will suffice here to say that upon energization of the magnets 1 and 8 by impulses, these impulses energize the magnet I0 and attract the armature 89, freeing it from the end of the bell crank arm 9|. When, as above described, the pins 48--48, either or both of them, move forwardly, they will leave their engagement with the equalizing bar |05 and the bell crank 98 will be free to be rotated clockwise around its pivot 99, as, for example, by a tension spring |06, to a position such as that in broken lines at When impulses cease, the energization of the magnet Cil I8 ceases (as described in said application) and the spring 88' will retract the armature 88. Movement of the armature 88 will be stopped on the end of the arm 8|.

when the bell crank is rotated counter-clockwise upon the restoring of the ratchet piece 41 in a manner to be described, the end of the arm 9| will engage and slide over a cam surface Iiii, im the armature 8! moving it counter-clockwise, and will hold it in this position by engagement with armature 88 on the relatively elevated portion |82.

As more fully described in said patent application, clockwise movement of the armature 89 will close the switch 84 and counter-clockwise movement will open it. The switch 84 controls energization and operation of a printing magnet indicated generally at I8, see Figs. 1 and. 5 disposed under the type wheel I and, in connection with an inking ribbon |84 and a paper strip |25, prints each selected character of the type wheel I upon the paper strip, the ribbon |84 and strip |28 being fed forwardly after each character is printed.

The operation of the printing magnet i2 also operates a switch shown generally at 21 which controls the energization of a restoring magnet I4, as described in said pending application.

The function of the restoring magnet I4 is to restore the parts mechanically and electrically to their original or normal condition after the printing of a character and in preparation for the printing of the next successive character. This will now be described.

It will be observed that at the time of energizing the magnet, I4, thertype cylinder I is in some one oi its selective positions and therefore, the ratchet pieces 41-41 are in one or another of their forwardly stepped positions.

A depending armature |88, Fig. 5, is pivotally mounted as at |88 to swing toward and from the magnet I4, a pole piece |48 being provided on the armature |38 upon which the ilux of the magnet I4 may act. The lower end of the armature |88 is pivotally connected to the two legs I4I-I4I of a U-shaped link |42, a pin |48 extending through the legs of the link and through the armature |38. A slot |44 in the legs |4I permits longitudinal movement of the ends of the pin |43 therein and a spring |45 is placed between the lower end of the armature |88 and the closed end of the link |42, whereby movement of the amature |88 may be initiated in quick response to the energization of the magnet I4 and without waiting for the inertia of the associated parts to be overcome. and movement of the armature transmitted to the link by the armature |88 may be cushioned to avoid shock and, for purposes of absorbing inertia of parts connected to the link |42, to permit the full stroke of the armature |88 to precede the movement of the said moved parts.

The legs I4I of the link |42 are pivotally connected as at |46 to the lower end of a lever |41 pivotally supported intermediate its ends and adjacent the pivot |46 on a ball bearing support 12. The opposite end of the lever |41 more remote from the bearing 12 is, as shown in Figs. 5 and 10, provided with a transverse bar 48 normally disposed forwardly of the pins 61 which depend from the ratchet pieces 41. And the lever |41 is also provided with a laterally extending pin |49 between the bar |48 and the bearing 12.

Upon attraction of the armature |38 by the :,osaece magnet I4 in the clockwise direction as viewed in Fig. 5, movement is transmitted through the link |42 to the lever |41, rocking it clocklf/ise around the bearing 12, causing the bar |48 o move to the right and engage the pins 81 in whatever forward position they may have been electively disposed, and to move them back to their normal position, during which movement thel pins 48 and the links 49 and 50 operate through the bell crank 58 and through the rack bar 55 to restore the printing cylinder to its normal position. The springs 58 and 8| continuously act tending to move the links 48 and 88 forwardly and thus, acting through the pins 48, exert forward thrust on the ratchet pieces 41-41, but upon the cornpletion of the rearward movement of the ratchet pieces 41, by means of the lever |41 as described, the ratchet pawls 45-48 will retain the ratchet pieces 41 in their rearmost or normal position.

The rearward movement of the pins 48 acts upon the equalizing bar IIII to rock the bell crank 88 counter-clockwise causing the end of the arm 8| thereof to move over the cam |8| against the tension of the spring |88, into a position to engage the portion |02 of the armature 88 in which position it may be subsequently held by a shoulder |82' on the armature. Thus the switch 84 is opened and held opened.

As will presently be referred to again, the magnet |4 will be de-energized after the lever |41 has moved through its stroke to reset the ratchet pieces 41, and to retract the lever |41 to a position suitable for its next operation, a spring |41' is provided connected at one end to the lever |41 and at its opposite end to a suitable point n the stationary frame of the apparatus, the spring functioning to exert a counter-clockwise torque on the lever |41. When the ratchet pieces 41 have been restored to their reset position and held there by the pawls as above described, the springs 88 are under tension and by their own reaction upon the head 1| tend to rotate the lever I 41 clockwise in opposition to the tendency of'the spring |41'. When the ratchet pieces 41 are ratcheted ahead, the tension in the springs I8 is gradually released, enabling the spring |41 to over-power the springs 88 and retract the lever |41. By suitably proportioning the tension of the springs 68 and |41', so that they suitably counter-balance each other, the retractive effort of the springs |41' will only be able to retract the bar |48 a relatively short distance from the pins 61, and as the pins advance with the ratchet pieces 41, the bar |48 will retreat ahead of them so that the bar |48 is at all times a relatively constant and relatively small distance away from the pins. Therefore, at each energization of the magnet I4 and resetting movement of the bar |48, the bar |48 moves only a short distance to engage the pin 61 whether the ratchet pieces have been moved ahead one notch or one tooth, or the complete range of teeth; and therefore, the bar v |48 engages the pins with the minimum of impact. The lever I 41 thus has a floating movement which maintains the bar |48 in readiness to eil'ect a resetting action in the minimum of time after energization ofjthe magnet I4, as well as with the minimum of shock.

At the completion of the operation of the restoring magnet |4 as above described, its own energizing circuit may be broken by the switch 84 or by the system of circuit and contacts and connections shown and described in said pending application and thereupon all the parts of the apparatus which have not heretofore been reset now move to their normal or reset positions and the entire apparatus is ready for another character printing cycle of movements.

It is to be observed that by sending impulses to both magnets 1 and 8 simultaneously, the type cylinder will rotate and move longitudinally, both movements occurring concurrently and thus the type cylinder is moved to its selective position with a screwing movement on all or a part of its selection movement.

By reference to Figs. 5, '1, 8, and 10, which illustrate an actual apparatus in which my invention may be embodied, and which apparatus has been developed into somewhat diagrammatic form in Fig. 1, it will be seen that the apparatus may conveniently be assembled upon a frame comprising a base portion 300, a floor portion 30| spaced vertically thereabove and a vertical wall portion 303 standing on or arising from an intermediate portion of the floor 30|.

As shown in Fig. '7 and partly in Fig. 5, the mechanism for selectively moving the type cylinder I may conveniently be mounted upon the floor portion 30|; and as shown in Fig. 5, the magnets I3, I4 and 'I and 8 may conveniently be disposed between the floor portion 30| and the base 300, the magnet |3 and its frame being conveniently suspended from the under side of the floor portion 30|, as may also the magnet |4 and its frame, and magnets 1 and 0, see also Fig. 7, may conveniently be disposed on the upper side of the base 300.

The magnet as indicated in Fig. '7 may be disposed at right angle to the floor portion 30| and may be disposed generally thereunder. To avoid complications of the drawings, this magnet has been illustrated in a horizontal position in Fig. 1, but it is believed that the construction thereof and of the correlated parts will be clear from Fig. 'l without further illustration or description.

In Fig. 5 a single magnet I4 is illustrated. In some instances I may employ two magnets, in which case the second magnet would be disclosed directly behind the magnet |4 illustrated in Fig. 5. In such case also it would be preferred to provide two magnetic circuits one for each magnet. As described hereinbefore the magnet circuit of the electro-magnet I4 comprises a horizontal element 3|| by which it may be supported on the oor portion 30|, a depending leg 3|2 and magnet core and magnet armature |40; and these parts are preferably duplicated except as' to the armature |40 when two windings are employed.

Such a two magnet construction is shown in Fig. 9 which may be considered as viewed from the plane 9 of Fig. 5, with the parts broken away at the pivotal bearing |39. The two magnet windings I4a|4a have a common yoke 320 and the armature |40 may be attracted by both magnet windings I4a|4a. The armature |40 has a central head portion 32| thereon transversely through which extends a short pin 322, the ends of the pin mounting the inner race elements 323--323 of ball bearings, the outer race elements of which 324-324 are supported in suitable bores in arms 325-325 of the common yoke 320.

The pin 322 corresponds to the pivot bearing element |39 in Fig. 5. By this construction the armature |40 may pivot around the ball bearings described and furthermore, which is an important feature of this construction, the magnetism from the magnets |4a|4a flows not only through the armature |40 and yoke 320 but on its way from one to the other ows into the head 32| and sends through the inner and outer bearing elements 323 and 324 and through the balls such as 326 therebetween.

'Ihe magnetism by attracting the balls and their race elements int'o tight engagement with each other, eliminate every trace of lost motion in these bearings, and at the same time, due to the ball type of bearing. does not introduce friction thereby; and furthermore, by this construction, a continuous magnetic path of low reluctance is provided, the only air gap being that between the cores of the magnets |4a,-|4a and the armature |40. Thus, a very efficient as well as silent and lost motion proof magnetic circuit and armature mounting is provided having properties particularly suitable and advantageous in mechanisms of the kind under consideration.

The actual construction of the armature 35 of the magnets 1 and 8 is to be particularly noted. In the preferred construction, the armature comprises a portion 3|5 disposed oppos-ite the core of the magnet, which portion is pivotally supported at 31, and a relatively slender rod portion 35 rising vertically therefrom, the upper end of which as plainly shown in Figs. 5 and l engages the arm 39 of the bell crank-form ratchet pawl supporting pieces. By supporting the magnet 1 on the base 300 and the ratcheting mechanism referred to upon the spaced oor 30|, a considerable length of rod portion 35 may be provided which makes it possible to so proportion the length and diameter of the rod portions 35 that they may bend under the force applied thereto by the windings 1 and 8. Thus for a considerable movement of the upper ends of these rod portions 35 it is only necessary to move the armature portion 3|5 a very slight distance and. the armature portion 3|5 may respond immediately to the impulses, followed by movement of the rod portion, the rod portion functioning as a resilient rectilinear bar spring. It will be observed that this movement of the rod portion 35 is distinctly different from that of an armature portion which merely moves under the influence of magnetism and is retracted by a spring, and in which the inertia of the parts must be continuously overcome, during their vibration, by the direct pull of the magnet.

The rod-like portions 35 have a natural frequency or period of vibration which may be made to correspond to the rate at which the impulses occur, and thus the effect of the magnetic impulses from the magnets 1 and 8 may be described as that of keeping the rod-like armatures in vibration rather than of bodily moving them.

The armatures 35 may be retracted in any suitable manner but I prefer to retract them by springs 3|63|6, Fig. 7, acting through the bell crank arms 39-39.

Having thus described my invention, I am aware that numerous and extensive departures may be made from the embodiment herein i1- lustrated and described, but without departing from the spirit of my invention.

I claim:

1. In a step-movement escapement selective mechanism for electrically actuated typewriters or the like, a ratchet piece comprising a body portion having parallel rows of teeth on opposite sides thereof, a double pawl having a tooth normally in engagement with the teeth of the rst row and a pawl'normally laterally spaced from the teeth of the second row, means for constraining the 'ratchet piece to move forward longitudinally. means for transversely reciprocating the pawl teeth. the teeth of the first row provided with a surface at right angles to the direction of movement and a surface at an angle of approximately 45 to the direction of movement, and the teeth of the second row provided with two faces at angles of approximately 45 to the direction of movement.

In a step movement escapement selective mechanism for electrically actuated typewriters or the like, a ratchet piece-comprising a body portion having a predetermined direction of movement, and provided with two rows of teeth, a 15 double pawl having a tooth engageable with the teeth of one row and a pawl engageable with the teeth of the other row, means for reciprocating the pawl teeth. the teeth of the first row provided with a surface at right angles to the direction of movement portion and a surface at an angle of approximately 45 to the direction of movement, and the teeth of the second row provided with two faces at angles of approximately 45 to the direction of movement.

3. In a step movement escapement selective mechanism for electrically actuated typewriters or the like, a ratchet piece comprising a body portion having two rows of teeth thereon, means for constraining the body portion to move forwardly in generally the direction of the teeth rows, a double pawl having two teeth alternately movable into the path of the rows of teeth upon reciprocation thereof, means for reciprocating the pawl teeth, the teeth of one row having each a surface extending from the body portion at an angle sufficiently near 90 with the path of movement of the teeth that when engaging one pawl toothin its path, it will stop movement of the body portion, and the teeth oi' the other row hav- 40 ing each a surface extending from the body portion at an angle sufficiently less than 90 with the path of movement that upon engaging the other pawl tooth in its path the tooth will tend to move said pawl tooth out of said engagement 45 and out of the path of movement of the ratchet teeth.

4.\In a step movement escapement selective mechanismfor electrically actuated typewriters or the like, a ratchet piece comprising a body 50 portion having two rows of teeth thereon, means for constraining the body portion to move forward in generally the direction of the teeth rows,

a double pawl having two teeth alternately movable into the path of the rows of teeth upon 55 reciprocation thereof, mea'ns for reciprocating the pawl teeth, means for constraining the body portion to move forward in generally the direction of the teeth rows, the teeth of one row having each a surface extending from the body portion 60 at an angle to the path of tooth movement sufficiently near 90 that when engaging one pawl tooth in its path, itvwili stop movement oi' the body portion, and the teeth of the other row having each a surface extending from the body portion at an angle sufficiently less than 90 to the path of movement that upon engaging the other pawl tooth the said teeth of the row will tend to move said pawl tooth out of said engagement 70 and out of the path of movement, and the teeth of both said rows having other surfaces extending from the body portion at an angle suficiently less than 90 that upon movement of the body portion in the reverse direction, the said teeth of 75 the body portion tend to move an engaged `pawl ing it to move in the tooth out of engagement and out of the path of movement.

5. In a step movement mechanism an element having a row of ratchet teeth, resilient means constraining it to move in the direction of the tooth row, a pawl and means to oscillate it to engage and disengage successive teeth of the row to permit a step bystep movement of the element in said direction, means for restoring the element by movement in reverse direction comprising an abutment on the element, an oscillatory arm connected to the resilient means and engageable with the abutment in one direction of oscillation to move the elements and in the other direction of oscillation disengaging the abutment and tensioning the said resilient means and means to oscillate the arm.

6. In a step movement mechanism an element having a pair of parallel rows of ratchet teeth, resilient means constraining the element to move in the direction of the tooth rows, a pawl and means to oscillate it to engage and disengage the successive teeth of the two rows alternately, tov permit a step by step movement of the element in said direction, means for restoring the element by movement in the reverse direction comprising an abutment on the element, an oscillatory arm connected to the resilient means and engageable with the abutment in one direction of oscillation,

and in the other direction of oscillation disen-` gaging the abutment and tensioning the said resilient means and means to oscillate the arm.

7. In a step movement mechanism an element having a row oi.' ratchet teeth. means constraindirection of the tooth row, a pawl and means to oscillate it to engage and disengage successive teeth to permit a step by step movement of the element in said direction, a mechanism controlled by movement of the element comprising a member having a telescopic connection with the step mechanism element and independently constrained to move relative thereto.

8. In a step movement mechanism an element having a pair of parallel rows of ratchet teeth, means constraining the element to move in the direction of the tooth rows, a pawl and means to oscillate it to engage and disengage the successive teeth of the two rows alternately to permit a step by step movement of the element in said direction, a mechanism controlled by movement of the element comprising a member having a telescopic connection with the said element and independently constrained to move relative thereto.

9. In a step movement mechanism a pair of elements having each a row of ratchet teeth, means constantly and independently constraining the elements to move in the direction of the tooth rows, a pawl associated with each element and means to oscillate it to engage and disengage the successive teeth of the element to permit a step by step movement of the element in said direction, an abutment on each element, a bridging element, means yieldably maintaining the bridging element in bridging engagement with both abutments, and a mechanism connected to the bridging element operable by movement thereof communicated thereto by movement of either or both step movement elements.

10. In a step mechanism a pair of elements each having a pair of parallel rows of ratchet teeth, means constraining each element independently of the other to move in the direction of the tooth rows, a pawl associated with each element 30 ing the element to move in and means to oscillate it to engage and disengage the successive teeth. of the two rows alternately of the associated element to permit a. step by step movement of each element in the said direction independently of the step movement of the other element, an abutment on each element, a bridg" ing element, means yieldably maintaining the bridging element in bridging engagement with said abutments, and a mechanism connected to the bridging element operable by movement thereof, communicated thereto by movement of either or both oi said step movement elements.

1l. l'n a step movement mechanism for typewriters and the like, a pair of elements having each a` row of ratchet teeth, means constantly and independently constraining the elements to move in the direction o the tooth rows, a pawl associated with each element and means to oscillate it to engage and disengage the successive teeth of the element to permit a step by step movement of the element in said direction, a multi-character cylinder movable selectively to printing positions by rotary and axial movements thereof, separate means ior moving the cylinder axially and rotatively, and means connecting said toothed elements respectively to said cylinder moving means.

l2. n a step movement mechanism, an element having a row of ratchet teeth, means constrainthe direction of the tooth row, an oscillatory bell-crank-form pawl, means to oscillate it by one arm thereof, the pawl having a portion of the other arm engageable and disengageable with successive teeth upon oscillation thereof and normally constrained in the direction to engage the teeth, and upon oscillation permitting a step by step movement of the element in the direction `of the tooth row and the means to oscillate the bell-crank being a resilient reed-like extension of an electro-magnetic vibratory armature overlapping the said bell-crank arm at an angle thereto. l

13. ln a step movement mechanism, an element having a pair of parallel rows of ratchet teeth, means. constraining the element to move in the direction of the tooth rows, an oscillatory bellcrank-form pawl, means to oscillate it by one arm, the pawl having a portion on the other arm engageable and disengageable with successive teeth of the two rows alternately upon oscillation thereof and normally constrained in the direction to engage the teeth oi one row, and upon oscillation permitting a step by step movement of the element in the direction of the tooth rows, the means to oscillate the bell-crank being a resilient reed-like extension of an electromagnetic vibratory armature overlapping the said bell-crank arm at an angle thereto.

WILLIAM C. ROE.

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