US2359617A - Magnetic recording apparatus - Google Patents

Description

Oct. 3, 1944.

J. W. BRYCE MAGNETIC RECORDING PPARATUS 9 Sheets-Sheet l Filed Nov. 29, 1941 INVENTOR.

ATTORNEY.

Oct. 3, 1944. J. w. BRYCE MAGNETIC RECORDING `APPARATUS Filed Nov. 29, 1941 9 Sheets-Sheet 2 TOR INV ,d

BY A

MHK/fw A TTORNEY Oct. 3, 1944. J. w. BRYcE v 2,359,617

MAGNETIC RECORDING APPARATUS Filed Nov. 29, -194l 9 Sheets-Shea?I 3 IN VEN TOR Y fw f ATTORNEY Oct. 3, 1944. J. w. BRYCE l 2,359,617

MAGNETIC RECORDING APPARATUS Filed Nov. 29; 1941 9 sheets-sheet 4 INVENTOR IA TTOHNEY Oct. 3, 1944. J. w. BRYCE 2,359,617

MAGNETIC RECORDING APPARATUS Filed Nov. 29, 1941 v9 Sheets-Sheet 5 naz IN V TOR BY I l ATTORNEY 9 Sheets-Sheet 6 J. W. BRYCE MAGNETIC RECORDING APPARATUS Filed NOV. 29, 1941 Ill.

INVENTOR 2' a@ TGRNEY Oct. 3,' 1944.

Oct. v3, 1944.

VJ. W. BRYCE MAGNETIC RECORDING APPARATUS Filed Np'v. 2911941 9"shee`tssheet 8 ATTORNEK 0a. 3, 1944, J. w. BRYCE 2,359,617

MAGNETIC RECORDING APPARATUS Filed Nov. 29, '1941 9 Sheets-Sheet 9 Flo-13g. 60

9o 12o 15a fao 21o 240 27o 30o 33o `a60 IN VE TOR ATTORNEY Patented Oct. 3, 1944 MAGNETIC RECORDING APPARATUS James W. Bryce, Glen Ridge, N. J., assigner to International Business Machines Corporation, New York, N. Y., a corporation of New York Application November 29, 1941, Serial No. 421,079

4 Claims.

This invention relates to magnetic recording apparatus, and particularly to such apparatus wherein discrete magnetic impressions or representations are recorded, on a magnetizable sheet, at different 4code or index point positions for representing the data desired. to be recorded.

An object of the present invention resides in the provision of an'improved and simplified apparatus for recording discrete magnetic data representations.

To this end, a keyboard control unit and a recording unit are provided, wherein a plurality of instrumentalities are selectively manipulated, at will, in the keyboard unit, in accordance with the data to be recorded, for controlling differentially settable devices, which devices, in turn, cause individual printing means and magnet selector means to be set at diierent positions for representing the data. Suitable means are provided for rendering the printing means operative to print the data at predetermined line spaces on the magnetizable sheet. Intermittently operable sheet feeding means are provided and called into action to present the sheet to the magnetic recording station upon complettion of the printing operation. A plurality of groups of recording magnets are provided at the recording station which are supported by cyclically operable positionable means for placing the said magnets in a recording or non-recording position. Sheet feeding operations are effected while the magnets are in a non-recording position. In the recording position, the magnetizable sheet is wedged between the magnet pole-pieces and a backing plate member of suitable magnetic material. The magnets are selectively connected in control circuits by the differentially settable magnet selector means, so that individual capacitor means are effective upon their discharge to energize the selected magnets of each related group, and thereby effect recording of discrete magnetic representations at predetermind code positions on the magnetizable sheet. Switching means are provided, which are operated in timed relationship with the printing means, the sheet feeding means, and the `magnet positioning means, for alternately connecting the individual capacitor means to individua-1 charging and discharging circuits, the latter circuits including the selected recording magnets, so that the selected recording magnets of each group are energized upon the discharge of the related capacitor means.

one or more coded discrete magnetic impressions or representations on a magnetizable sheet.

Another object of the present invention resides in the provision of cyclically operable means for placing a group of recording magnets in recording and non-recording positions, the operation of which is under control of the will of the operator.

Another object of the present invention resides in the provision of an improved magnetic recording apparatus wherein the magnetizable sheet is wedged between the pole-pieces of a group of magnets and a backing plate member of suitable magnetic material, whenever-the said magnets are placed in a, recording position.

Another object of the present invention resides in the provision of an improved magnetic recording apparatus wherein intermittently operable sheet feeding means are provided for advancing the said sheet only at such times when the group of magnets are in a non-recording position.

Still another object of the present invention resides in the provision of means operated in timed relationship with the magnet positioning means for effecting the discharging of the said condensers only at the times when the recording magnets are in a recording position.

Still another object of the present invention resides in the provision of an improved recording unit wherein a plurality of recording magnets are retained in spaced relationship in a common member of magnetic material.

Still another object of the present invention resides in the provision of an improved recording unit wherein a common backing plate member of magnetic material is positioned opposite the group of spaced recording magnets in order to concentrate the flux in separate perpendicular paths in the magnetizable sheet.

Still another-object resides in the provision of improved magnetic recording apparatus wherein the data is printed on predetermined line spaces on the sheet at one station, and recorded magnetically at Ipredetermined areas on the sheet at another station, whereby each area containing the magnetic representations bears a xed linear relationship to the related area or line space in which the printed data is formed.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a perspective View of the keyboard control unit with the attached recording unit.

Fig. 2 is an end view, partially in section, of the units shown in Fig. 1, with the cover plates removed.

Fig. 3 is a sectional View of the recording unit,

along the lines 3 3 inFig. 8.

Fig. 4 is asectional view of the recording unit, taken along the lines 4 4 in Fig. 8.

Fig. 5 is a sectional View, taken along the lines 5 5 of Fig. 8.

Fig. 6 is a sectional View, taken along the lines 6 6 in Fig. 3.

Fig. '1 is a sectional view, taken along the linesV 1 1 in Fig. 8.

Fig. 8 is an elevational view, partly in section, of the recording unit.

Fig. 9 is a detail view showing the various settings of the conducting arms of the magnetV selector means.

Fig. 10 is a detail view of the recording magnets in the recording position.

Fig. 11 is a circuit diagram showing the circuit connections of the machine.V

Fig. 12 is a timing chart.

Fig.Vr 13 is a fragmentary view of the record sheet.

Fig. 14 shows the combinational code used herein for representing the data.

Fig. 15` is a sectional view of the record sheet.

Keyboard control unit Referring now to Figs. 1 and 2, the keyboard control unit, generallydesignated by the refer` ence character A, willv be described brieily. It will be understood, 'as the description progresses, that the purpose of this unit is merely to provide manipulative instrumentalities, such as keys 20, for eiecting the selection of predetermined control elements in the magnetic recording unit; in

accordance with the selected keys. For illustrative purposes, a-specic and well known type of keyboard Vcontrol unit, which is called into operation at will, is shown for exercising the desired selective control over the said recording unit. Ob;- viously, other types of'manipulative control units can be used to effect such selective control, therefore, due to the fact that a keyboard control unit of the cash register type is employed in the present embodiment, it is not to .be construed that the present invention is limited solely to be controlledby such mechanism.

The construction and operationV of the illus.-

trated keyboard control unit is well known, and

as mentioned is of the cash register type, therefore, the brief general description to-be given now Y is believed sufficient for complete comprehension `of the present invention.

The structure of this keyboard control unit issimilar to the structure shown and described in U. S. Patent No'. 1,816,263, dated July 28, 1931, thus',.for a complete and detailed description of the mechanism of the presentV keyboard control' unit, reference should be made to this last mentioned-patent.

A plurality of similarly constructed banks of keys areprovided, three banks of amount designa- -tion keys, andone bank of' classication designation keys. The keys comprising each bank are slidably mountedV in separate key frames 2l, i

. to the normal undepressed positions.

"frio Each depression of the said motor` bar causes the motor driven cam shaft 24 to be driven through one complete rotation by a train of well known mechanism, which is described in detail in the said Patent No. 1,816,263. Upon rotation of the said cam shaft 24, a restraining and restoring bar 25 is rocked first in a clockwise direction, and then a counterclockwise direction. During the rocking of the said bar 25 in the clockwise direction, an actuator 26 is permitted to be rocked, under the influence of a spring 21, until stopped by the end of a depressed key 20, or by a zero stop pawl, in the event no key in a bank is depressed. After the actuator 26 has been positioned under control of one of the keys 20, the said actuatorand bar 25 are restored to' their home positions.

Pivoted on the crossrshaft or rod 28, adjacent each of' the segmental actuatorsV 26, is a companion segment 29 provided with teeth 3|! identical and concentric with the teeth 3| of each related actuator 26. Each indicator segment 29 is also provided with teeth` 32, which mesh with a related -gear 33. Each ofthe gears 33 provided is secured to one end of a cross shaft 34 or one of the nested sleeves 35 surrounding the said cross shaft 34; Each gear 33 also meshes with a related `gear 36, which gear 36' meshes with the related pinion 31 secured to a corresponding indicator wheel 38. ,e

The mechanism provided in the present keyboar-d control' unit for adjusting the indicator wheels 38 is of the type in which the indicatorsY are always rst brought to zero, and then adjusted to their new positions under control of the provided differential mechanism.

Each indicator segment 29 is provided with an abutting face 40, so, as the restraining and. restoring bar 25 is rocked, in a clockwise direction, it contacts the abutting ,faces of such of the indicator segments 29, as may stand in other than their home positions, to restore them and all of the, corresponding indicators 38 to their zero positions.

It Will be remembered that during the forward movement of the restraining and restoring bar 25, the adjacent actuators 26, are under. control of the depressed keys 20. After all of the indicator segments 29 have been set to their Zero positions, and the actuators 26 are adjusted, common control pinions (not shown) are adapted to engagev the teeth30 and 3| of the segments 29 and actuators 26, respectively. After this engagement, the restraining and restoring bar 25 is returned to its home position, thereby returning all of the actuators 26 to their home positions. Since the related actuators 26 and segments 29 are nowengaged with a common control pinion,

it is apparent that the segments 29 are positioned differentially to-adjust the related indicators 38, by means of gears 33 and 36, to different positions 'to indicate the selected amount represented bv the depressed keys 20.

Thus, it is seen, upone operation of the manipulative instrumentalities, by depressing the selected keys 20andthe motor bar 23 (or if de; sired by turning theV crank 4I instead of calling in the said `motor -bar), the cam shaft .24fis rotated one revolution to set-or adjust the corresponding indicator Wheels 33 from their home or Zero positionsto different positions to indicate the amount or data represented by the.y selected and depressed keys. It should be remembered too that each'correspondinggear 36 isr also differentially positioned to control the positioning of the related indicator. It should be mentioned, also, that secured to the said cam shaft 24 is a gear 42 which meshes with an idler gear 43, both of which are set into operation, upon rotation of the cam shaft. The purpose of this drive will be explained presently, in conjunction with the description of the recording unit.

Recording unit The recording unit, generally designated by the reference character B (Figs. 1-3) is arranged as a distinctly separate and detachable unit from the keyboard control unit A. Certain control elements, which will be described later, of the recording unit are adapted to engage the differentially positioned gears 36 and the idler gear 43 of the keyboard control unit A, when the said recording unit B is attached to the said unit A.

I'he recording unit B comprises, generally, two sections, namely, the magnetic data recording section, and the data printing section. By means of the magnetic recording section, the selected data, represented by the depressed keys 20, are recorded magnetically upon a strip or sheet of magnetizable material. The magnetic representations or impressions representing the selected data are discrete magnetic impressions formed on the magnetizable record sheet at predetermined code or index point positions. These coded magnetic impressions will be referred to as discrete magnetic index points to distinguish from the well known form of sound tracks represented by the continuous magnetic impressions recorded on suitable magnetizable materials.

In addition to recording magnetically theselected data, this data is also printed on the magnetizable record sheet by means of the said printing section. It will be seen that the printed data is disposed so as to bear a xed linear relationship with the magnetic index points representing the data and corresponding to the said printed data. It has been found by experiment that this provision is a necessary one, because in the machines adapted to be controlled by the magnetized sheets or strips formed by the present invention, it is important that certain indicating marks, such as the printed data, be provided, in order to assure that the magnetized sheets are properly positioned, in the machines to be controlled thereby, with respect to a xed reference point in the controlled machine. Therefore, in addition to interpreting the magnetic index points, the printed data become fixed indicating marks, which bear a xed linear relationship to the magnetic data index points, whereby it can be determined whether or not the said magnetized sheets are properly positioned in the machines controlled by such sheets or strips. A controlled machine of this character is described and claimed in Patent 2,302,002, issued November 1'1, 1942.

Magnetizable 'record sheet-Referring now to Figs. 13-15, a suitable magnetizable record sheet or strip 50 is shown to comprise a paper carrier or base 5! which is coated with magnetizable granular material 52, and a layer of paper 53 suitable for receiving printed impressions covering the said magnetizable material. To this end, suitable metal powder or filings may be suspended or mixed in any suitable binder and sprayed or coated on one of the plies or layers of paper. This binder may contain suitable adhesive material in order to bond securely the magnetizable material to both plies of paper, and

thus form a unitary structure of the three layers of material. If preferred, other types of magnetizable record material can be used, for example, one of the types shown in Figs. 4 to 9 of U. S. Patent No. 2,254,931.

In Fig. 13, a fragmentary section of the continuous record sheet 50 is shown and comprises individual records formed thereon at equally spaced intervals, which are indicated by the reference characters a-c. Each individual record comprises a line of printed data, as indicated by the reference character 54, which printed data correspond to the magnetically recorded data, and a plurality of discrete magnetic index points, indicated by the reference character 55. Obviously, the magnetic impressions on the record sheet are not visually discernible, but are merely indicated, by the shaded areas l55, to show the code positions of certain of the data representing magnetic impressions. code employed to represent various data is shown in Fig. 14. The code or index point positions for the available columns on the record sheet are shown by the cross marks in the first individual record a on the sheet. It is to be noted that the printed data 54 of each record is disposed at a predetermined and fixed location on each record, and that the magnetic index points are disposed in a predetermined and xed area on each record. The linear relationship between the line of printed data -54 and the magnetic index points 55 is a fixed relationship, which arrangement will be described in more detail hereinafter. It should be mentioned too, that the usual marginal or:

feed perforations 56 are provided in the instant record sheet 50.

Record feeding leaner-Referring now to Figs. 2 4, and 8, it is seen that the record sheet 50 is fed from a supply roll S0 over the idler rollers 6l, past the printing station generally designated 62, the magnetic recording station generally designated 63, idler roller 64, sprocket feed roller B5 to the take-up roll 66. The record sheet is fed, once each cycle, near the end of each cycle, as indicated in the timing chart (Fig. 12). feeding operation occurs between the printing operation and the magnetic recording operation, the purpose of which will become apparent. The mechanism for effecting the intermittent record sheet feeding operations will now be described.

The idler gear 43, which is driven by gear 42 on the cam shaft 24, meshes withra gear 61 secured to the main shaft 68 of the recording unit, and suitably supported therein by the side plates 49. Also, secured to the said main shaft 68 is a mutilated driving gear 69, the teeth 1D of which, engage, during the rotation of shafts 24 and 68, the teeth 1I of the mutilated gear 12, thereby effecting a partial rotation of gear 12, for each revolution of gear B9. The said mutilated gear 12 is secured to the sprocket feed roller B5, which roller 65 in turn is rotatably mounted on a stud shaft 13 suitablysupported by the intermediate plate 14. The teeth 1|] and 1! of gears 69 and 12, respectively, are arranged so that, for each partial rotation or intermittent movement of gear 12 and feed roller 65, the record sheet 55 is advanced a predetermined distance D, as indicated in Fig. 13.

An expedient friction drive for the take-up roll 66 is provided, and comprises a gear 15 also secured to gear 12 which meshes with an idler gear 16 rotatably supported by the arm 11 which gear 16 in turn meshes with gear 18 rotatably mounted on a. stud shaft 19 carried by the said The combinational arm 11. Secured to gear 18 is a rol1er 80 provided with suitable friction 'rolls 8|. The arm 11 ispivotally supported by the stud shaft 13 and by means of spring 82 is urged in a counterclockwise direction (as Viewed in Fig, 4) so that the driven friction rolls 8| always engage and effect positioning of the take-up roll 86, during the intermittent record feed operations.

Magnetic recording means.-Referringnow to Figs. 3, 4, 8 and'lO, the means for electingthe magnetic recording of the selected data on VVthe magnetizable sheet 50 at the generally designated magnetic recording station 63 will now be Y described.

A plurality of individual recording magnets 85 are provided, each of which has'a slightly protruding pole-piece 86, which pole-pieces are rectangularly shaped as shown in Fig. 8. These recording magnets are supported by a common retaining block 81 of suitable magnetic material, such as softiron, which block 81 is provided with a plurality of spaced apertures 88= for receiving and retaining the indiw'dual magnets. A plurality of vertically arranged columns or rows of apertures 88 are provided, each column or row having, in the instant case, four equally spaced apertures. The individual magnets 85retained by a column or row of four apertures (see Fig'. 8) will be referred to as a group of recording magnets. The arrangement of the said apertures is such that each magnet of a group is spaced vertically so as to correspond to the vertically spaced index point positions of a column indicated in Fig. 13, and the individual groups of magnets of each column are spaced horizontally to correspond to the individual columns of index point positions indicated in Fig. 13.

The retaining block 81 is mounted on a member 8S constructed of suitable electrical insulating material, which member in turn is secured to one arm of a bell crank lever 90. The said lever 90 isV rotatably mounted on a sleeve 9| supported by the cross shaft or rod 92. The othery arm of bell, crank lever` 90r is pivotally connected to one end of a cam follower arm 93, the other end of which is bifurcated to partially surround the shaft 68'. A cam roller 9!! is suitably disposed on the said follower arm 93, which cam roller 94 rides on the periphery of the cam element 95, the latter being secured to shaft 68.

The normal or,home position of the mechanisrn just described is shown in Figs. 3 and 4, whereby the said retaining block 81 and the groups of magnets 85 supported thereby are maintained in a position so that the pole-pieces 86 of the magnets 85 are held away from the magnetizable record sheet 50. This position of the groups of recording magnets 85 will be referred to as a non-recording position.

Now, upon rotation of the shaft 68, the cam element 95, near the end of each cycle of rotation of shaft 68, causes the cam follower arm 93 to be raised to its uppermost position and thereby cause the retaining block 81 and the groups of magnets, supported by the bell crank lever 90, to be partially rotated in a clockwise direction. Due to this operation, the magnets are positioned in what will be termed hereinafter as the recording position, i. e., the magnets are positioned, as shown in Fig. 10, so thatthe pole-pieces 86 of the magnets 85 contact the magnetizable record sheet 50 at the index point positions of the individual records as indicated in Fig.'13.

At the said recording station 63, the magnetizable record sheet 50 rests againsta backingplate or block 96V of suitable magnetic material, such as soft iron, which is supported by one of the side plates 49 and the intermediate plate 14. The said backing plate member 96 israrranged to extend beyond the area, both verticallyl and horizontally, to be recorded on the said magnetizable record sheet. Thus, it is seen, particularly in Fig. 10, that when the groups of magnets 85 are positioned in the recording position,'the polepieces 86 thereof not only are placed in intimate contactlwith the magnetizable sheet 50 butfactuallywedge` the magnetizable sheet between the said pole-pieces and backing plate member.

When the said magnets 85 are positioned in the described recording position, means'tobe described later herein are effective to select certainA magnets of each group and connect these se lected magnets to circuit energizing means to energize the selected magnets, and thus cause discrete magnetic impressions to be recordedin the code or index point positions;` on the magnetizable sheet in accordance with the selected data set up on the keys of the keyboard control unit. It has been determined, by experiment, that, by using a backing plate of highly permeable material having low retentivity characteristics, on the side of the highly retentive record sheet opposite the magnet pole-pieces, greater concentration of the magnetic eld or flux,- in a path perpendicular to the surface of the record sheet is obtained. It is to be noted that not only is the surface of the backing plate against the record sheet greater'in area than the area to be recorded onthe record sheet, but also that the thickness of the backing plate is substantially the same as the lengthof the entire pole-piece of each magnet. For static recording of the type described herein, that is, the type of magnetic recording on record sheets wherein the latter are held stationary during the recording operation, and wherein discrete magnetic impressions are formed, it has been found desirable to employ backing plates of relatively greater thicknessin order to prevent spreading of the iiux between the designated index point positions.

Recording magnet selector means.-Referring now to Figs. 5, 6, 8 and 9, Vthe individual means for eecting the selection of certain magnets of each group Will be explained. Each of the said individual means` comprises an arcuaterbank of fixed contacts |00, which contacts are disposed, at equally spaced positions, in an electricallyA insulating segmental member |0I. In addition thereto, each segmental member |0| is provided with a common elongated contact member |02. An individual-bank of contacts |00 and |02 is provided for each column of data to be recorded on the magnetizable sheet, or stated in other Words, a bank of the said contacts is provided for each vertically arranged group of magnets 85. The individual segmental members carrying the said contacts are held in a suitably spaced relationship by the individual spacing blocks |03, which assembly is suitably secured to one of the side Plates 49.

Individual sets of spaced conductingv means |04- are provided for each arcuate bank of contacts and |012. Each set, in the instant case, consists of six radial conducting arms |05 which form an integral part of the common arcuate Vconducting segment |06, which arms are arranged to engage and connect predetermined ones of the contacts |00 to the common elongated contact |02 depending upon the settings of each of the set of conducting arms. In Fig. 9,

the different combinations of the connection of the contacts to the common conducting contact |02 are shown for each setting of the rotatable conducting arms |05.

Each of the said common arcuate conducting segments |06 is fixed to an individual arcuate insulating strip |01, which in turn is secured to a suitable annular member |08. With reference now to Fig. 6, the individual annular members |08a.-d are shown to be connected to individual actuating means which will now be described. Member |085; is secured to a sleeve |09a which sleeve in turn is fixed to a shaft IIO supported at its ends by the side plates 49. Alsol fixed to the shaft [I0 is another sleeve I|I to which a segmental gear ||2a, is secured. Members IllSb to |08d are secured to the ends of the nested sleeves |092; to |09d, respectively, which sleeves |09bd surround the said shaft IIO and have secured thereto the segmental gears II2b, |I2c, and |I2d, respectively. Each of the said segmental gears IIZa-d is arranged to mesh with a corresponding indicator drive gear 36.

It is remembered, upon operation of the keyboard control unit, that the positioning of the said gears 36 is under control of the selected and depressed keys 20, and that the gears 36 are differentially positioned in accordance with and corresponding to the selected keys. Since the segmental gears IIZw-d are in constant mesh with the said gears 36, gears IIZa-d, sleeves I09a/-d and connected conducting arms |05 are differentially positioned or set in accordance with the settings of the gears 36. Thus, it is understood that various combinations of the contacts |00 of each bank are selected in accordance with the selected keys 20, which combinations of selected contacts are representative of the selected data. It will be described later herein, how the magnets 85 which are connected to the individual contacts |00, and selected by the described selector means, are energized to effect the recording of the magnetic index points representing the selected data.

Printing means-Referring now to Figs. 4, 6 and 8, it is seen that individual type segments I I 5a to 5d are also secured to the differentially positioned sleeves |II, |0919, |090, and |09d, respectively, so that the individual type elements |I6, disposed on the said type segments, are' selectively presented to the printing position, at the printing station 62, to permit printing of the selected data on the magnetizable sheet 50 in accordance with the selection of the data keys 20, whenever the said sleeves and related segmental gears II2a-d are operated. In view of the detailed description just set forth regarding the positioning of the said sleeves, further description regarding the positioning of the related type segments I I 5cl-d is not deemed necessary.

In order to eect printing of the data upon the magnetizable sheet, the following means are provided. A print control cam element ||5 is secured to the shaft 68 for cooperating with the cam follower arm |I6 which is provided with a cam roller I I1, the latter riding on the periphery of cam element II5. The cam follower arm |I6 is bifurcated at one end and partially surrounds shaft 68, the other end of said arm being pivotally connected to an extension arm II'I of a bell crank lever I |8 which lever is rotatably mounted on the cross rod 92. The depending arm |l9 of lever ||8 is provided with a camming surface |20 against a which a stud I2I, fixed on an extension arm |22 of a lever |23, is urged by means of spring |24. Lever |23 is pivotally mounted on cross rod 92 and at its upper extremity is provided with a transverse bail or hammer |25, which bail carries a suitable printing bar |26, which in the instant case consists of rubber material. The said bail and bar extend transversely across the faces of the-type segments II5, so that the positioned type elements ||6 are engaged thereby, at the printing station 62, when the said hammer arrangement is released to effect printmg.

Now, upon rotation of the said shaft 68, the cam element ||5, near the end of each cycle of rotationv of shaft 68 (namely, the 265 point in the cycle, see Fig. 12), causes the cam follower arm II6 to be raised to its uppermost position, causing the print hammer arrangement to be in the maximum cocked position. The cam follower arm II6 is constantly urged in a downwardly direction, as viewed in Fig. 4, by the spring |21 secured to bell crank lever ||8 and the intermediate frame 14. As the cam follower arm is raised by cam element II5, the depending arrn ||9 is partially rotated in a clockwise direction, thereby permitting the spring urged lever |23 land hammer arrangement including bail |25 and bar |26 to be partially rotated in a clockwise direction. At the 2'65" cycle point, the cam roller II'I drops from the high point of cam ||5 to release the spring urged hammer arrangement, whereupon the bar |26, directed in a counterclockwise direction, is momentarily forced against the magnetizable sheet 50, which in turn is forced against the positioned type elements to effect printing of the data accordingly,

The usual inked ribbon medium |28 is provided between the type segments and the magnetizable sheet, which ribbon medium is advanced to and from the printing station by mechanism old and well known. A ribbon feed actuating mechanism is provided, and briefly comprises a pivoted lever |29 (see Figs. '7 and 8) having a pair of spaced arms |30 and |3I, which arms are provided with cam lrollers |32 and |33, respectively. The said rollers |32 and |33 ride on the peripheries of complementary cam elements |34 and |35, respectively, the latter being fixed t0 shaft 68. The cam actuated lever |29 operates the pivoted link |36, which link in turn actuates the ribbon feed mechanism generally designated |31, at the times indicated in Fig. 12, during the rotation of shaft 68.

It was mentioned hereinbefore, that the magnetizable sheet is fed one time each machine cycle, i. e. for each complete rotation of shaft cated by the reference characters a to c. Immediately after recording the selected data in the predetermined line space presented to the printing station 62, the sheet 50 is advanced, by the feed mechanism described herein, a fixed distance, indicated by the reference character D in Fig. 13. Thus, the next line space for receiving the printed data is presented to the said printing station, which printed data is recorded during the cycle following the just mentioned sheet feeding operation.

The predetermined area in which the magnetic index points are recorded is a fixed distance from the corresponding line of printed data. 'I'his area is presented to the magnetic recording station Ihe magnets 85 are held in the recording posi- Y tion from the 335 cycle point to the 345 cycle "l point. Individual switching means are provided for controlling the energization of the recording magnets at approximately the 340 'cycle point,

'which willnow be described.

'Switching means-Referring now to Figs. Y5, l'

8 and 11, a plurality of individual switching vmea'nsfiare provided, such Vas camr` operated contacts'lato l'dd and IMa. to fldl'd, the former being a group of normally closed contacts, and the latter-a group of normally `opened contacts. The contact assembly generallydesignated by 4the reference character |42, is suitably mounted on one of the side lplates 49. Theoperation's of each set of -contacts of thementioned-groups are under control of a 4single and common Vcam element |43 which is secured to'the'shaft 68. The

said cam element 43 Yis provided with la single notch or depression |44, which, during'operation ofthe shaft-68, is effective yatapproximately'the f338 rto 342 cycle points to permit thepivoted AfollowerV arm |45 to be partially rotated ina clockwise direction, due to the action of the camming element |56 momentarily dropping vinto the said notch |44. Upon partial'rotation` of the follower arm U35, the group-of normally closed contacts Iot-d are opened momentarily and the groupof normally opencontacts Ulla/d are `closed momentarily.

Thus, it will be seen, in-connection with the `description of the circuit diagram, that theoperated groups of contacts are'eiective'to' control the energizaticn ofthe vrecording.magnets l85, when the v-latter are in the recording position. It is seen that the operation of theswitch- 'ing means just described is effected'in timed 'relationship with the operated sheet feeding means, dataprinting means, and the positoningmeans for the recording magnets.

Operation Referring now to Figs. 11 and 127,the operation of the machinewill be described in conjunc "tion with the circuit diagram. It is-seen that an individual Contact |00 of each 'magnet selector 'means is connected Ito an individualmagnet coil `|35.

The magnet coils are connected in groups of fours in the individual condensers ISM,` |501),

1'|5|Jc, and |5807., which condensers, in turn, are `connected to the normally closed'contacts. I'40'a, |4l|b, |400, and Mild, respectively. The last'm'e'ntioned contacts, in'turn, are `connected Lbyi' the common conductor to one terminal of a" suit- Vable power supply, such as the`rectier unit, 'designated by the referencecharacter |53. (The other terminal of the power supply is connected bythe common conductor V|52 tol the common terminals of each'group of' magnets`85, andlone lterminal of'each related condenser. Each elongated contact |02 of the said selector means-(is connected to a corresponding one Aof the groupof Vnormally open contacts |4|a to Ld. llla'ch-group of four magnets 85 in Fig. l1, correspondsgto the `individual'magnets of each vertical groupor Acolumnshovvn in'Fig.-8.

For-'the idescribed conditions, vit is seen that the output circuit ofthe rectier unit |453 is connected directlyto the individual condensers |50a to d by means of the related switching means, namely the individual'sets of normally closed contacts |4a. to d, respectively, to charge the saidcondensers. These individual charging circuits are maintained throughout the machine cycle until approximately the 340 cycle point, at'which time the described charging circuits are disconnected from the said rectier unit, by virtue of the opening of contacts |40a to d, and individual discharging kcircuits are established,by virtue of the closure of the contacts |4|a to d. The magnets of each group are selectively connected to the individualand related discharging circuits by means of said magnet yselector means. The selection of the magnets 85 of each group depends upon the settings of the annular members |08a tod and the related conducting arms |05.

Upon closure of the contacts |4|a to d, the condensers |5066 to d are connected to the individual discharging circuits, which circuits include certain selected magnets 85 of each group, to effect energization of the selected magnets due tothe discharging of the related condensers.

In summarizing, it might'be desirable to trace the operations of the main control elements described hereinabove, and the control circuits of the machine for a specic example, therefore, let us assume that the data 0.12R is set up on the manipulative instrumentalities of the keyboard control unit by depressing the corresponding data keys 20 in'each of the banks or orders. Upon depression of the motor bar. 23 (or operation of the crank 4|) thecam shaft 24 is set into operation to `cause the' indicator gears 36 to beset at different positions by the described differentially settable means inaccordance with the settings of the depressed data keys 20. The said gears 36 Vin turn cause the typesegments ||5a, to d and the corresponding annular'members |08arto d to be set or positioned accordingly to represent the selected data. The shaft 6B of the recording unit is also set into operation to elect the following sequential and timed operations (l) operation of the ribbon feed mechanism, (2) cooking or setting of the print-hammer arrangement during the to 265` cycle points, (3) printing of the setup data (01.12B) on-the record sheet 50 at the 265' cycle point, by releasing the-said vmagnets85 into recording positionduring the 250 to 335 cyclepoints, andV maintaining the saidvmagnets in recording position during the 335 to 345 cycle points, and (6) rendering the individual switching means operable approximately atV the 340 cycle point, under control `of the common control means, such-as cam 9MB', which is operated in timed relationship with-the above-mentioned elements to open the setsvof contacts |4011 tod and'close the sets of contacts In this manner, the individual condensers `|50a to Qdi` are Valternately connected to :the rectifier `unit- 53 to be charged,and.to the selectedlmagnets-85` of each related group'to energizelthese fmagnets by the condenser discharges.

In Fig. 11,*the annular niemberslSa-toffd andthe corresponding` conducting arms -'|!05 \are shown l in the proper ,positionsfor vrepresenting the selected data 0.12R. Now upon closure of the said contacts |4|a to d the condensers |50a to d are connected in the following discharging circuits respectively: (1) one terminal of the charged condenser |50a to contacts |4|a, conducting segment |02, conducting arms |05, engaged contacts |00, related magnets 85-I and 85-3 to the other side of condenser |50a, energizing said selected magnets to effect recording of the magnetic impressions in the iirst and third index point positions to represent the character R, as indicated in Fig. 13 by the shaded areas; (2) one terminal of the charged condenser |50b to contacts MIb, conducting segment |02, conducting arms |05, engaged contact |00, related magnet 85-3 to the other terminal of the said condenser |5012, energizing the selected magnet to effect recording of the magnetic impression in the third index point position to represent the character 2 as indicated in Fig. 13; (3) the terminal of the charged condenser |500 to contacts |4|c, conducting segment |02, conducting arms |05, engaged contact |00, related magnet 85--4 to the other terminal of the said condenser |500, energizing the selected magnet to effect recording of the magnetic impression in the fourth index position to represent the character 1, as indicated in Fig. 13; and (4) one terminal of the charged condenser |50d to contacts Mld, conducting segment |02, conducting arms |05, engaged contact |00, related magnet 85| to the other terminal of the said condenser |5011, energizing the selected magnet to effect recording of the magnetic impression in the first index point position to represent the character 0, as indicated in Fig. 13.

Immediately upon the discharging of the condensers |50a to d, the contacts |4|a to d are opened and contacts |40a to d are closed to connect the said condensers to the described charging circuits, in order to charge the condensers for further recording operations. The positioned groups of magnets 85 are also returned to their non-recording positions during the 345 to 360 cycle points, so that during the following cycle of operation, the desired data can be printed on the proper line space, and the record sheet then be advanced to the magnetic recording station as described.

Thus, it is seen that discrete magnetic index points are recorded in different index point positions to represent the desired and selected data set up on the keyboard control unit. By employing the condenser discharge principle for energizing the selected magnets, as inexpensive and simplified apparatus is provided for producing the necessary magnetizing currents. Also, magnetizing forces of constant values are produced by employing this principle, which is important, in order to insure that the remanent fields of each of the magnetic index points are approximately of the same relative magnitude. Another feature residing in the present case, due to the use of the condenser discharge principle, is protection aiforded to the recording magnets. The windings of these magnets necessarily must be of a limited current carrying capacity, since they must be restricted in size, due to the required close spacing thereof; and therefore, if,

for some reason, the connection between the power supply and the recording magnets (contacts Mld-d) were to become fixed or stuck for a. relatively long time, the recording magnets would be subjected to the magnetizing currents possibily sufiiciently to burn out their windings, if the condenser discharge principle were not employed.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that Various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A magnetic recording apparatus for recording coded discrete magnetic representations on a magnetizable sheet comprising a plurality of recording magnets, a common retaining block of magnetic material provided with a plurality of spaced apertures for receiving the said recording magnets, means for supporting the said block and magnets on one side of the magnetizable sheet, a common backing plate member of magnetic material, and means for supporting the backing plate member on the other side of the said sheet opposite the said recording magnets.

2. In an apparatus for recording discrete magnetic code spots on a magnetizable sheet material, a backing member of magnetic material of high permeability and low retentivity, a supporting member adjacent thereto,- a group of recording magnets mounted on said supporting vmember and having protruding pole pieces facing said backing member, one of said members being movable outward from the other member, to provide a gap between said pole pieces and said backing member to receive the magnetizable sheet material; means to move said movable member torward the other member tQ squeeze the magnetizable sheet material between said pole pieces and said backing member, and means to energize said recording magnets.

3. In an apparatus for recording discrete magnetic code spots on a magnetizable sheet material, a backing member of magnetic material of high permeability and low retentivity, a supporting member adjacent thereto, a group of recording magnets mounted on said supporting member and having protruding pole pieces facing said backing member, one of said members being movable outward from the other member, to provide a gap between said pole pieces and said backing member to receive the magnetizable sheet material, means to feed the magnetizable sheet material intermittently through Said gap, means to move said movable member toward the other member to squeeze the magnetizable sheet material between said pole pieces and said backing member, means to energize said recording magnets; and means to operate said feeding means, said moving means, and said energizing means in timed relation, so that said recording means is energized while said magnetizable sheet material is squeezed between said pole pieces and said backing member and during intermissions in the operation of said feeding means.

4. Apparatus as described in claim 2, wherein selective control means are provided to select one or more of said recording magnets for simultaneous operation by said energizing means.

JAMES W. BRYCE.

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