US2130229A - Printing mechanism - Google Patents

Description

sept. 13, 1938.

NJ. A. cLosE ET AL PRINTING MECHANISM Filed May 15, 1956' 5 Sheets-Sheet l RNS INVENTOR` SePt- 13, 1938- J. A. cLosE ET Al.

PRINTING MECHANISM F'i1 ed May l5., 1956 5 Sheets-Sheet 2 INVENTORS,

Sept. 13, 1938. J. A. cLosE ET A1.

PRINTING MECHANI S M Filed May 15, 1956 5 Sheets-Sheet 3 ooooooo oooooooooooO a ooooooooooo ooooooooooo oooooooooooo ooooooooooo m em n .A

Sept. 13, 1938. J. A.'c| osE ET Al.

PRINTING MECHANISM Filed May l5, 1936 5 Sheets-Sheet 4 Sept. 13, 1938. i, A. CLOSE ET Al.

yPRINTING MECHANI'SM Filed May 15, 193e 5 Sheets-Sheet 5 Patented Sept. 13, 1938 `UNITED STATES PRINTING MECHANISM James il. Close, Dn Bois, and Sidney R. Colline,

' Clearfield, Pa..

Application May'is, 193s, serial No. vasos 14 Claims.

This invention relates to mechanism for I printing and more particularly is Vconcerned with f apparatus adapted to print .desired insignia upon tracings, drawings, show-cards, and other relatively large individual sheet material.- o

Heretofore a number of mechanisms have been. provided for printing or typing on relatively small pieces of sheet material. These specifically include the typewriter and like apparatus. However, in the printingof tracings, drawings and show-cards of considerable size no automatic printing mechanism has been employed, and it has been the usual practice to either print by hand or to'employ individual rubber stamps for applying each letter. lNeedless to say, the hand methods are relatively slow, cumbersome, and entail high labor costs. In addition, the resulting job is often unsatisfactory due, of course, to the lack of uniformity of hand work and to the fact that, unless painstaking care is exercised by the skilled artisan, the resulting printing may be messy with improperly or poorly formed let-V ters, as will be appreciated.

It is the general object of our invention to L avoid and overcome the foregoing and other diiliculties of prior known apparatus by the provision of an improved form of automatic keyboard control printing device particularly adapted to apply desired insignia, for example, letters ao and numerals, upon relatively large sheets such as tracings, drawings, and cards. A

Another object of our invention is to provide a mechanism for typing or printing in combination with a blue-printing apparatus for producing blue-prints from a typed-on tracing, for example.

Another object of our invention is the provision of novel means for selecting any desired insignia to be printed which means are rapidly and accurately controlled by a keyboard.

Another object of our invention is to provide printingor typing apparatus of the character indicated in which the particular style, size and shape of the type employed is readily interchangeable with any desired type.

vision of typing mechanism'having a typing bed or plate which is transparent.

The foregoing and other objects of the invention which will become evident as the description proceeds are achieved by the combination of a transparent plate with means for releasably securing a sheet to be printed on 'the plate. vAvshaft extending substantially parallel to the plate supports'a printing-wheel toAwhich the individual type insignia are removably fas- Another object of our invention is the pro` tened and means are provided `for changing the angular position of the wheel to present any desired insignia adjacent the plate. lMechanism is included in the combination for moving the shaft parallel to the plate with other lmeans for 5".

moving the wheel along the shaft to thereby provide for printing the selected insignia at any point on the sheet. Additional means for relatively moving the wheel and plate towards each other to effect the printing of the sheet are like- 1o wise incorporated in the combination.

- In the accompanying drawings Fig. 1 is a front elevation of one embodiment of apparatus constructed in accordance with the principles of our invention. Fig. 2 is a vertical transverse crossl5 sectional view of the apparatus illustrated in Fig.

1. Fig. 3 ls a sectional plan-view oi' the apparatus of Figs. 1 and 2 with the section being taken on line III-III of Fig. 2. Fig; 2, inciden'- tally, is taken'substantially on line lI-II of Fig. 20

3. Fig. 4 is an enlarged sectional plan view of. the electrical control mechanism forming a part of our invention and taken substantially on line IV--IVof Fig. 2. Fig. 5 is a vertical transverse cross-sectional View of the electrical control 25 mechanism as taken on line V-V of Fig. 4. Fig.

6 is'a wiring diagram of the electrical connections for part of the apparatus.

Referring to the drawings, the numeral I 0 indicates generally a casing usually made of wood 30 paneling secured to a suitable irn frame and having a transparent screen or printing bed I2 ordinarily made of plate glass and mounted in a. frame I 4 secured in an opening inthe front of the casing. 'l'he screen I2 may be oset relative 35 to the front of the casing, as best seen in Fig. 3, and is `mounted for movement relative to the casing so that the back of the screen can be A readily exposed. 'I'his is preferably accomplished by securing the frame I4 to the casing along one 40 vertical side by hinges I6 with `,the other side of the frame being releasably secured, as by fastenings I8, to the casing so that when 4desired the fastenings' I8 can be loosened and the screen moved like a door outwardly of the casing to 45 expose the back side of the screen.

The tracing, drawing, placard, or the like. which is to be printed is removably secured to the screen I2 in any suitable manner. We pre1'- erably utilize-rubber-covered rollers 20 adapted 50 `to be moved to opposite ends of the screen or to positions over the edges of the sheet material held on the screen. The rollers 20 are received at their ends in slotted bars 22 extending vertically of and secured to the frame Il. Its structure readily permits the rollers 26 to be moved by hand to any desired holding position to thereby .removably secure the sheet material to the back side of the screen I2.

Adjustably mounted and positioned in the casing I6 is a printing mechanism forming part of our invention and indicatdgenerally by the numeral .26. The mechanism includes horizontally extending rails 36 and 32 which are secured at their ends to vertically extending members 34 fastened to the ends of the casing I6. 'I'he rails 36 and 32 support a carriage 36 having wheels 36 and 46 engaging' with tracks 36 and 32, respectively. The carriage 36 carries bearings 42 and 44 which rotatably journal a vertically extending shaft 46. Feathered to'the shaft 46 is a printing-wheel or disc 48 which is formed with a grooved periphery adapted to removably mount type 56 of any desired sizor character. Ordinarily the type 56 is of semi-hard rubber or, if desired, can be made of metal and backed with a cushioning strip of rubber.

The vertical position of the printing-wheel 46 on the feathered shaft 46 is controlled by vertically extending screws 54 and 56 which are journaled at their ends inthe frame 36 and which carry a yoke 56 having threaded hubs 66 engaging with the threaded portions of the screwsl 54 and 56. The yoke 56 has a central hub portion 62 surrounding the shaft 46 but formed with an elongate opening 64 therein which permits movement of the shaft 46 towards the screen I2, as hereafter described. The lower ends of the screws 54 and56 are connected by a shaft 66 and suitable bevel gears 66 and 1.6, and means are provided for driving the shaft 66. These means' preferably will function regardless of the position of the carriage 36 on the tracks 36 and 32 and, in the embodiment of our invention illustrated, clude a reversible motor 14 mounted on the bottom of the casing I6and driving a shaft 16 extending along the bottom forward portion of the casing.

A driving connection between shafts 16 and 66 v is provided by securing a frame 16 to the bottom ofthe carriage 36, which frame not only` Journais the shaft 66 but also journals an idler shaft 66 and extendsto and surrounds the shaft 16. The shaft 16 is splined longitudinally and carries a gear 62 meshing with a gear 64 on the idler shaft 66 which, in turn, meshes with a gear 66 upon the shaft 66 carried with the carriage 36. By this mechanism even though the position of the carriage 36 on the tracks 36 and 32 is changed, the frame 16 moves the gear 62 along the splined shaft 16 so that a drive to the shaft 66 is effected. i

Means may be incorporated with the drive positioning the yoke'56 so vthat the exact vertical printing position of the printing-wheel 46 with respect to the .transparent screen I2 is indicated at .all times. These means may comprise vertically extending shafts 36'positioned at each end of the casing I6 and connected by beveled gears|62 to the shaft 16. The shafts 66 are threaded and carry nuts 94 .which are connected by a quickly removable gauge wire 66. The'oifset of the transparent screen I2, as best seen'in Fig. 3,

positions the gauge wire 96 in front of the glass, and, as will be evident, the arrangement of the parts is such thatas the printing-wheel 46 is moved up and down on the shaft 46 the gauge wire 66 likewise moves up and down in front of the transparent screen |2 in suitable slots between the casing and the screen so that the verbical height of the printing-wheel behind the screen is indicated.

The yoke 56 preferably carries rollers or other means for inking the printing-wheel 46 and in the embodiment of the invention illustrated the yoke pivotally supports arms 61 having self-linking rollers 96 mounted on their ends. A tension spring 99 connects the arms 61 .resiliently together and serves yieldably to hold the inking rollers 66 against the periphery of the printingwheel.46. We further contemplate the use of inking ribbons rather than rollers as will be understood.

Any desired mechanism for controlling the lateral position of the carriage 36 on the tracks 36 and 32 can be utilized but we preferably employ a motor |66 which is mounted upon the bottom of the casing I6 and which drives a screw |62 journaled in suitable supporting bearings |64 secured to the bottom of the casing I6. The carriage, as best seen in Fig. 2 of the drawings, is formed with a downwardly extending bracket |66 which is threaded and receives the screw |62. 'I'his manner of operation of the motor |66 moves the carriage 36 in one direction or the other upon the tracks 36 and 32. In order to indicate the lateral position of the carriage 36, arms |61 and I61a are secured respectively to the top and botytom of the carriage and are connected by a quickly releasable gauge wire |66 which is positioned in front of the screen I2 and extends through slots formed between the screen and casing.

, As above stated, the shaft 46 carrying the printing-wheel 46 is journaled in bearings 42 and 44 which are carried in the frame 36 for^move ment to and from the transparent screen I2 to effect the printing of any sheet material thereon. Preferably the movement of the bearings 42 and 44 to and from the screen I2 is controlled by electric magnets |I6 with tension springs ||2 being provided to return the bearings 42 and 44 to a position against stops ||4 secured to the carriage. As best seen in Fig. 6, the magnets ||6 are connected to a source of electric current by an operating key. or jack switch IIS.

'I'he control or selector apparatus for determining the position of `the printing-wheel 46 is indicated generally by the numeral |26 and, as best seen in Figs. 4l and 5 of the drawings, includes a housing |22 of non-magnetic material surrounding the .shaft 46 and carrying a plurality of stator' pole magnets |24 arranged in a double circle as shown in Fig. 4. The shaft 46 carries diametrically extending rotor magnets generally in thelforrn of two'pairs |26 and |26. The' rotorlmagnets are formed with pole pieces extending into closely-,spaced relationship with the pole pieces of the stator magnets |24.-

The operation of the selector mechanism vis controlled by a keyboard indicated as a whole by the numeral |36 and operative to electrically energim the rotor magnets |26 and |26 and any selected set of stator magnets I24-so as to swing the'printing-wheel 46 to a position so that the insigne to be printed corresponds to the particular insigne key operated. More particularly, Fig. 6

illustrates diagrammatically the wiring connectionsl of our selector mechanism. The numeral I 34 indicates the electrical input line connected by a four-way, single-throw, jack switch |36 to the stator and rotor magnets respectively. The jack switch |36 is controlled by a particular key |36 marked, for example, with the letter Q, The .key is, of course, positioned with various other keys on the keyboard control mechanism 30. f

From the jack switch |36 electrical leads |48 extend to one diametrically opposite set of stator magnets |24 and, as seen in the diagram, the opposite magnets are wound oppositely so that they present opposite poles both at their tops and bottoms. From the jack switch |36 electrical leads |42 extend to a two-pole double-throw jack switch |44 operative by a. shift key |46 on the keyboard control mechanism |30, as hereafter more fully described. From the jack switch |44 electrical leads |48 are connected to slip rings |50 carried by the shaft 46 and electrically connected to the rotor magnets |26 and |28, as indicated. I'he rotor magnets |26 are oppositely wound so that a north pole is providedlat one end and a south pole at the other and the rotor magnets |28 are also wound oppositely but with their positions reversed so that a south pole is provided at one end and a north pole at the other with the north pole of rotor magnets |26 being above the south pole of rotor magnets |28 and vice versa.

It will .be recognized from the foregoing that when key'|38, for example, representing the letter Q, is depressed upon the control keyboard |30, the rotor magnets |26 and |28 are energized and that a certain diametrically opposite pair of stator magnets is also energized. Thus through magnetic attraction of unlike poles, the. rotor magnets |26 and 28 rapidly swing shaft 46 and thus printing-wheel 48 to a position to bring the letter Q to printing position opposite thetransparent screen i2. In an exactly similar manner the remaining keys of the control mechanism |30 are connected to the rotor and stator magnets so that by pressing the proper key the letter to be printed and carried by the printing-wheel 48 is moved to printing position.'

An important part of our inventive concept is the provision of reversing mechanism for changing the polarity of either the rotor magnets |26 and |28 or the field magnets |24. Ordinarily this is accomplished by the provision of the doublepole, double-throw jack switch |44 connected in the electrical leads |42 to the rotor magnets and operated by the key |46 above described. It will be recognized that operation of the jack switch |44 changes the polarity of the rotor magnets |26 and 28 in accordance with known practice. Accordingly, we mount lower case letters on the printing-wheel through an arc of 180 and provide upper case or capital letters upon the 180 of remaining surface. Thus when "shift key |46 is depressed the jack switch |44 functions to change the polarity of the rotor magnets |26 and |28 to bring the portion of the wheel carrying the capital letters to printing position with the proper capital being selected by the particular energized stator magnets |24. Normally when the shift key |46 is up, the polarity of the rotor magnets is unchanged and lower case letters are printed as will be understood. In operation the shift key |48 is used like the ordinary shift key on a typewriter, for example, and this key may be either locked in capital printing position or merely held down during the printing of capitals.

It should be understood that we contemplate making the jack switch |36 of a single-throw, double-pole construction or even of a single-pole, single-throw construction, and connecting the electrical leads |42 from the rotor magnets |26 directly with the input |34 at all times the machine is being operated. This modification, oi.' course, reduces the electrical switching and wiring costs and is generally advisable. For purposes of simplyillustrating the inventive principles the wiring diagram has, however, been made as illustrated. We also contemplate providing bars which extend below each line of keys on the keyboard control mechanism |30 so that when any key is operated the bar below the key is moved to operate a jack switch electrically connecting the rotor magnets in the electrical circuit.

The electrical selector mechanism just described provides a relatively inexpensive but rapidly operating and efficient mechanism for moving the printing-wheel 48 to position to print any desired insignia. By the use of the shift key arrangement either one half or the other half of the printing-wheel can be utilized. Ordinarily the strength of the combined rotor magnets 26 and |28 and the stator magnets |24 is entirely ample to swing the shaft 46 and printing-wheel 48 as desired even though the rotor magnets are stopped at a position a considerable arcuate distance from the particular stator magnets energized. -We do, however, contemplate providing contact plates between the rotor and stator magnets so that, if the arcuate distance from the rotor magnets is suiliciently great from the selected stator magnets energized, certain of the stator magnets closer to the rotor magnets will be energized. This shunting arrangement lies wellwithin the skill of the ordinary electrician and accordingly it has not been illustrated or described in detail. v

Associated with the shaft 46 and the selector mechanism |20 are means for insuring accurate positioning of the printing-wheel 48 before and during the printing. 'Ihese means may compose a disc |60 secured to the shaft 46 and formed with an upstanding edge flange |62 carrying a plurality of V-shaped notches spaced in accordance with the spacing of the letters upon the printing-wheel 48. A bracket |64 secured to the housing |22 is formed with a tapered guide |66 which in the normal non-printing position of the y shaft 46 is spaced just inwardly of the ange |62.

However, when magnets ||0 are energized to move the shaft 46 and printing-wheel 48, toward the transparent screen I2, the tapered guide |66 engages in one of the notches positively aligned with the letters on the printing-wheel. Continued movement of the` shaft 46 towards the transparent screen I2 causes a thicker part of the guide |66 to engage in the selected notch and 'in this manner a. very accurate placement of the letter on'the printed sheet is assured. K

We preferably include means in the apparatus for indicating the particular angular position of the printing-wheel 48 and in the form of our invention illustrated these means comprise an indicatilig-wheel |14 which is substantially identical to the printing-wheel 48 except that thev diameter of the indicating-wheel may' be slightly smaller. 'Ihe indicating-wheel is adapted to have mounted upon its periphery in exactlythe same manner as the printing-wheel 48 the vari-y in printing position, the printing letter Q car-y ried by the printing-wheel 48 actually is in printing position. `Ordinarily the indicating-wheel |14 is positioned closely adjacent to the transparent screen I2 so that its characters can be seen by the operator even though a translucent' or opaque sheet is held in printing position upon an upper part of the transparent screen I2. We also contemplate extending the transparent screen I2 down suillciently low so that the indicating-wheel can be positioned at the lower portion of the screen so as not to interfere with the placing of sheet material to be printed upon the upper portion of the screen. Again, a separate transparent window may be provided in the front of the casing I0 opposite the indicating-wheel |14.

While for the sake of clearness and ease of illustration the indicating-wheel |14 and the guide disc |60 have been shown and described as independent oi' each other, we preferably unite them in the commercial form ofY our printing mechanism. More specifically, the disc |60 is inverted and secured to the under side of the wheel |14 and the tapered guide |66 is fastened on the upper side of bracket |64 so as to engage with the flange |62, so that the function of the parts is retained as will be understood.

Since our improved printing apparatus includes a transparent screen or plate upon which the material to be printed is held during the printing operation, our apparatus adapts itself particularly to associated blue-printing and like operations. Accordingly, we provide upon the carriage 86 blue-printing lights which may com-v prise vertically directed light sources |80 positioned at one or both ends of the carriage. In all events if a blue-printing operation is desired either in conjunction with or separate from the printing operation, the material to be blueprinted is placed upon the transparent screen I2 and one or both of the light sources |80 are energized and the carriage 36 is moved along in front of the screen by operation of the motor |00 to achieve the desired result. The blue-printing lights, suitably reduced in intensity as by a rheostat, may be used for illuminating the printing screen before, during, or after printing, and we further may include other illuminating means for the same purpose.

It is believed4 that the operation of the apparatus will be understood from the foregoing description. Briey summarizing, however, when using the apparatus to print upon tracings, drawings, placards, and the like, the fastening means .I8 at one side of the transparent screen I2 andr l in place and the gauge wires 96 and, |08 are reconnected. Now an operator seated at the control mechanism can readily position the printing-wheel at a position shown by the gauge wires 86 and |08 so that the printing mechanism,

when' operated prints the desired insignia at the proper place on the tracing. Now the particularf letter or other insignia desired as indicated upon the keyboard' |30 is selected by depressing the particular key as, for example, that shown at |88 in Fig. 6, and with the letter selected the printing key ||6 forming a part of the keyboard |30 is depressed to energize magnets ||0 which pull shaft 46 and printing-wheel 48 toward the transparent screen I2 to positively force the particular printing insignia against the tracing carried by the screen. The motor |00 is then actuated by a spacing key |84 to move the carriage 36 one or more spaces along the tracing. No details of the spacing key have been illustrated, other than in Fig. 6, as the key merely comprises a switch for the motor |00. We do, however, contemplate making the spacing automatic with the incorporation of a controlled timing or operating switch on the motor so that the motor once started spaces any preselected distance and then stops. Likewise the motor 14 controlling the vertical position of the printing-wheel 48 relative to the screen I2 can also be energized by operation of af'spacing key |86 to position the printing-wheel vertically of the tracing. The next letter or other insignia to be printed is then selected by depressing the proper key uponl the control mechanism |30 and the printing operation lis repeated. In this manner as many letters and the like can be printed upon the tracing or other sheet material held-as may be desired.

The letters carried by the printing-wheel can be readily changed as to particular size or characteristic as will be understood. The apparatus functions in a'substantially rapid and automatic manner to print accurately upon tracings and other similar sheet materials. In addition, the blue-printing mechanism can readily be used in `conjunction with the printing operation. We contemplate employing the blue-printing Vlight sources |80 as means for illuminating a tracing from the rear to assist in proper positioning of the tracing for printing. Likewise, mirrors can be incorporated in the apparatus in order to more properly position the printing-wheel at the desired printing station. We also contemplate broadly-providing a transparent screen or window at the back side of the casing I0 and then pomtioning the control mechanism |30 at such window and. operating the mechanism while looking through the window to insure the proper positioning of the printing-wheel.

Any portions of the mechanism which are apt to be magnetically affected are made of non-m88- netic material where such effect is undesirable. Likewise the printing-wheel 48, indicating-wheel |14, and the disc |60 are made of aluminum or other light weight material to reduce the inertia thereof to facilitate easy and rapid operation of the apparatus. Q

While in accordance with the patent statutes one particular embodiment of our invention has been illustrated and described in detail, it should be understood that the invention is not limited thereto or thereby but is defined in the appended claims.

. We claim:

1. In combination, a plate, means for releasably securing a sheet to be printed on the plate, a shaft adjacent the plate, a printing-wheel carried by the shaft, electrical magnet means for changing the angular position of the wheel to present any desired insignia in juxtaposition to the plate, electrically driven screw means for moving the shaft parallel to .the plate, electrically driven screw means for moving the wheel along the shaft and relative to the plate, and electrical solenoid means for relatively moving the wheel and plate bodily towards each other to effect printing` of the sheet.

2. In combination, a screen, means for releasably securing a sheet to be printed on the screen, a shaft extending-substantially parallel to the screen, a printing-wheel carried by the shaft,

electrical selector magnet means for changing the angular position of the wheel to present any desired insignia adjacent the screen, electrically 3.A printing apparatus comprising a casing,A

a plate glass window removably forming a part of a wall of the casing, means for mounting a piece of sheet material to be printed. on the back of the Window, a carriage, means slidably mounting the carriage inthe casing for movement parallel -to the Window, means controlling the lateral position of the carriage, a shaft, bearings journaling the shaft in the carriage in vertical position, a printing-wheel carried by the shaft, a plurality Vof printing insignia carried by the wheel, means controlling the vertical position of the wheel on the shaft, rotor magnets carried by the shaft, stator magnets mounted in a ring around the rotor magnets and supported by the carriage, a keyboard connected to the magnets and adapted to control the supply of electric current to any selected set of magnets upon operation of any key to move a selected insigne to printing station, and mem-s for moving the shaft bearings toward the window to effect a printing operation.

4. A printing apparatus 'comprising a` plate glass Window, means for mounting a piece of sheet material to be printed on the back of the window, a carriage, means slidably mounting the carriage for movement parallel to the window, means controlling the lateral position of the carriage, a shaft, bearings journaling the shaft in the carriage in vertical position, a printing-wheel carried by the shaft, a plurality of printing insigniar carried by the wheel, means controlling the ver tical position of the wheel on the shaft, rotor magnets carried by the shaft, stator magnets mounted in a ring around the rotor magnets and supported by the carriage, a keyboard connected to themagnets and adapted to control thesupply of electric current .to any selected set of magnets upon operation of any key to move a selected and adapted to control the supply of electric curtrolling the lateral position of the carriage, a

insigne to printing station, and means for movl ing the shaft bearings toward the window to effect a printing operation.

5. A printing apparatus comprising a plate glass window, means for mounting a piece of sheet material to be printed on the back of the window, a carriage, means slidably mounting the carriage for movement parallel to the window, means controlling the lateral position of the carriage, a shaft, bearings journaling the shaft in the carriage, a printing-wheel carried by the shaft, a plurality of printing insignia carried by the wheel, means controlling the position of the wheel on rent to any selected set of magnets upon operation of any key to move a selected insigne to printing station.

7. A printing apparatus comprising a casing, a plate glass window removably forming a part of a wall of the casing, quickly releasable means mounting the window in the casing, means for mounting a piece of sheet material to be printed on the back of the window, a carriage, means slidably mounting the carriage in the casing for movement parallel to the window, means conshaft, bearings journaling the shaft in the carriage in vertical position parallel to the wind/ow, a printing-wheel carried by the shaft, a plurality of printing insignia carried by the wheel, means controlling the vertical position of the wheel on the shaft, means for controlling the angular position-of the Wheel, and means for moving the shaft bearings toward the window to effect a printing operation.

8. Printing mechanism comprising a plate adapted to support the material to be printed, an arcuate member, printing insignia removably mounted on the arcuate member, a plurality of pairs of rotor magnets movable with the arcuate member, a plurality of pairs of stator magnets defining a xed circle surrounding the rotor magnets, meansfor supplying electric currentto the rotor magnets and one selected pair of stator magnets, means for changing the direction of current iiow in the rotor magnets, means for moving the arcuate member against the plate to effect a printing operation, means for positively centering the arcuate member and the plate, and means indicating the position of the arcuate member relative to the plate.

9. Printing mechanism comprising a plate adapted to support the material to be printed, an arcuate member, printing insignia mounted on the arcuate member, rotor magnets movable with the arcuate member, a plurality of pairs of stator magnets dening a xed circle surrounding the rotor magnets, means for supplying electric current to the rotor magnets and one selected pair of stator magnets, means for changing the'direetion of current ow in the rotor magnets, means for moving the arcuate member against the plate to effect a printing operation, means for positively centering the arcuate member and the plate, and

means indicating the position of the arcuate member relative to the plate.

10. Printing mechanism comprising a plate adapted to support the material to be printed, an

Varcuate member, printing insignia mounted on the shaft, rotor magnets carried by the shaft,'

stator magnets mounted in a ring around the rotor magnets and supported by the carriage, a keyboard connected to the magnets and adapted tocontrol the supply of electric current to any the arcuate member, rotor magnets movable with the arcuate member, a plurality of pairs of stator magnets dening a fixed circle surrounding the rotor magnets, means for supplying electric current to the rotor magnets and one selected pair selected set of lmagnets upon operation of 'any l key to move a selected`insigne to printing station, and means for moving the shaft bearings toward the window to eifect a printing operation.

6. A printing apparatus comprising a shaft, a printing-wheel carried by the shaft, a plurality o! printing insignia carried by the wheel, means controlling the position ofthe wheel on 4the'shaft rotor magnets carried by the sham-stator mag- I nets mounted in a ring around the rotor magnets, and a keyboard connected to the magnets 'of stator magnets,'means for moving the arcuate member against the plate to eiect a printing operation, and means for positively centering the arcuate member and the plate.

11. -Printing mechanism comprising a plate adapted to support the. material to be printed, an arcuate 'member,` printing insignia mounted on the arcuate member, rotor magnets movable with the arcuatefmember, a plurality of pairs of stator ra'glits e'nig a xed circle surrounding the rotor magnets, means for supplying electric current to the rotor magnets and one selected pair of stator magnets, and means for moving the arl cuate member against the plate to eiect a printing operation.

12. Printing mechanism comprising a plate adapted to support the material to be printed, an arcuate member, printing insignia mounted on the arcuate member, rotor magnets movable with the arcuate member, a plurality of pairs of statorI magnets defining a ilxed circle surounding thel the arcuate member, rotor magnets movable with the arcuate member, a plurality of pairs of stator rotor magnets, means for supplying electric current to the rotor magnets and one selected pair of stator magnets, and means indicating the position vof the arcuate member relative to the plate.

14. In combination, a plate, means for releasably securing a sheet to be printed on the plate, a printing-wheel mounted adjacent the plate,

means for changing the angular position of the wheel to present any desired insignia in juxtaposition to the plate, means for moving the wheel parallel to the plate in two directions at -right angles to each other, means for relatively moving the wheel and plate towards each other to eiect printing of the sheet, and meansl comprising wires crossed infront of the plate for indicating the position of the wheel in front of the plate.

JAMES A. CLOSE.

SIDNEY R. COLLINS.

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