US3618120A

US3618120A - Magnetic drum assembly

Info

Publication number: US3618120A
Application number: US829850A
Authority: US
Inventors: Richard B Hanbicki
Original assignee: Madatron Corp
Current assignee: Madatron Corp
Priority date: 1969-05-15
Filing date: 1969-05-15
Publication date: 1971-11-02
Anticipated expiration: 1988-11-02

Abstract

A compact, lightweight magnetic drum assembly driven by synchronous motor means. The motor and drum assembly are respectively supported by separate mounting plates. A shaft for rotatably mounting the drum assembly is supported in a recess provided in the drum assembly mounting plate. The drum assembly is rotatably mounted upon the shaft. The rotor assembly is directly mounted upon and secured to the drum assembly so that the two components effectively form one rotating assembly. One of the mounting plates adjustably receives a magnetic head assembly, the adjustability allowing proper alignment of the magnetic heads relative to the magnetic surface of the drum as well as providing the proper air gap therebetween.

Description

United States Patent [72] Inventor Richard B. Hanbicki 2,915,358 12/1959 Richards 346/74 MD Princeton Junction, N.J. 3,119,102 1/1964 Braen B4G/174.1 F [21] Appl. No. 829,850 3,174,152 3/1965 Maclay. 346/74 MD [22] Filed May 15, 1969 3,390,385 6/1968 Ehalt 346/138 [45] Patented Nov. 2, 1971 Primary Examiner-Terrell W. Fears [73] Assignee lglillglporatm Assistant Examiner-Howard W. Britton Continuation-impart of application Ser. No. Anomeynostrolenk Faber' Gerb & soe 731,421, May 23, 1968, now abandoned.

[54] MAGNETIC DRUM ASSEMBLY ABSTRAT: A compact, lightweight magnetic drum as- 10 Claims 15 Drawing Figs sembly driven by synchronous motor means. The motor and drum assembly are respectively supported by separate mount- [52] U.S. Cl 346/74 MD, lng plates- A Shaft folrotatably mounting the drum assembly ls 340/1 74-1 F 346/138 supported in a recess provided in the drum assembly mounting [5I] Int. Cl G0ld15/'l 2, plato The drum assmnbly ls rotatably mounted upon the shaft G1 lb 5/4861 1b 5/76 The rotor assembly is directly mounted upon and secured to [50] Field ofSearch 346/74 M, the drum assembly so that the two components effectively 74 MD 138; 340/174-1 F form one rotating assembly. One of the mounting plates adjustably receives a magnetic head assembly, the adjustability [56] References Cited allowing proper alignment of the magnetic heads relative to UNITED STATES PATENTS the magnetic surface of the drum as well as providing the 2,905,933 9/1959 Canepa B4G/174.1 F proper air gap therebetween.

2 i l l, nl" i6 Z6.: 262 5; /4 l y' 276 g 'U15 27a. 'j

K /e 27d PAH-immuun 19H 3.618 120 SHEET l UF 4 PATENTEB Nnvz mx SHEET u UF 4 MAGNETIC DRUM ASSEMBLY This application is a continuation-in-part of application Ser. No. 731,421, filed May 23, 1968, now abandoned.

yThe present invention relates to magnetic storage means, and more particularly to a novel magnetic drum assembly which is of lightweight, compact size and of the utmost simplicity of design.

There exist a variety of applications wherein storage means must be provided for any one of a variety of purposes. One typical example is a character display assembly, as set forth in detail in copending application Ser. No. 718,553, filed Apr. 3, 1968, by the instant inventor and assigned to the assignee of the present application. One objective of the character display system described therein is to achieve optimum compactness in arrangement and overall dimensions to allow adaptability of the display system within any type of system requiring a visual display capability. The character display system described in the above-mentioned copending application employs a memory means for storage of character and/or symbol information signals. The memory system to be described hereinbelow lends itself admirably to use in the character display system of the above-mentioned copending application in that it is compact in size, light in weight and has a simplicity of design to assure its reliability in operation and ease in disassembly for inspection and/or maintenance activities.

The magnetic memory means of the present invention is comprised of a synchronous motor designed to drive the memory drum at a predetermined substantially constant angular velocity. The motor is mounted upon one member comprising a mounting assembly.

The synchronous motor drives a rotor assembly mounted upon and rotatable with a shaft joumaled within at least one bearing assembly, which is secured to said one member. The magnetic drum is comprised of a substantially cylindricalshaped member open at one end and being provided with an annular-shaped surface which is press-fitted with a cooperating flange provided on the rotor assembly, thereby securely mounting the rotor upon the cylindrical member for direct rotation therewith. No mechanical engagement is required between the motor and the rotor-drum assembly. The cylindrically shaped member surrounds the rotor assembly and is positioned in close proximity to the synchronous motor so as to greatly minimize the overall width of the assembly measured along the longitudinal axes of the cylindrical member, shaft and synchronous motor, all of which axes are coincident with one another.

The mounting assembly movably receives a magnetic head assembly. The adjustability feature facilitates alignment of the magnetic heads relative to the drum surface as well as facilitating adjustment for providing the desired airgap between the magnetic heads and the drum surface.

It is, therefore, one object of the present invention to provide a novel magnetic drum memory assembly which is light in weight, compact in design and of the utmost simplicity.

Another object of the present invention is to provide a novel magnetic memory storage means comprised of a synchronous motor, a rotor assembly, and a cylindrical-shaped magnetic drum member directly mounted to the rotor assembly so as to completely surround the rotor assembly and Ie in close proximity to the synchronous motor to provide a very compact arrangement.

Yet another object of the present invention is to provide a novel magnetic memory storage means comprised of a synchronous motor, a rotor assembly, and a cylindricalshaped magnetic drum member directly mounted to the rotor assembly so as to completely surround the rotor assembly and lie in close proximity to the synchronous motor to provide a very compact arrangement and wherein the assembly is mounted upon a two-piece housing provided with means for adjustably mounting a magnetic head assembly thereto, facilitating alignment between the drum surface and the magnetic heads, and further facilitating the provision of a proper airgap therebetween.

These as well as other objects of the present invention will become apparent when reading the accompanying description and drawings in which:

FIG. 1 is a perspective view showing the fully assembled housing.

FIG. 2a is a view of the housing assembly of FIG. l looking in thedirection 2-2'.

FIG. 2b is an elevational view of the housing assembly of FIG. l in which a portion thereof is broken away to expose the head assembly.

FIG. 2c is a view of the housing assembly of FIG. l looking in the direction shown by arrows 2'-2' and with the housing cover plate removed.

FIG. 3 is a sectional view of the assembly taken along the lines 3-3 of FIG. 2b.

FIG. 4 is a perspective view showing the magnetic head retainer clip also shown in FIG. 2a, 2b and 3.

FIG. 5a is a top view, partially sectionalized, of another preferred embodiment ofthe present invention.

FIGS. 5b and 5c are side and end views, respectively, of the embodiment of FIG. 5a.

FIG. 5d is a sectional view taken along the lines A-A of FIG. 5b.

FIG. 6a shows a plan view of a housing for mounting the drum-rotor assembly and magnetic head assembly comprising still another preferred embodiment of the present invention.

FIG. 6b is a sectional view of FIG. 6a looking in the direction of arrows A-A.

FIG. 6c is a sectional view of FIG. direction of arrows B-B.

FIG. 6d is an end view of the embodiment shown in FIGS. 6ta-6c.

FIG. 7 is a plan view of a housing portion employed with the assembly portion of FIG. 6a.

Refcning now to FIGS. l, 2a-2c, 3 and 4, there is shown therein a magnetic drum assembly l0 comprised of a housing 1l and housing cover plate l2. Housing Il has a substantially U-shaped configuration formed by a central portion lla integrally joined with substantially spaced parallel sides 1lb and llc (note especially FIG. 3). The central portion lla and sides 1lb and llc` are each provided with a pair of marginal edges 13a through 13e, respectively, which are bent or otherwise formed so as to provide curved portions defining grooves for slidably receiving the cooperating edges of cover plate l2 which likewise has a substantially U-shaped configuration which is defined by a central portion or top cover plate portion 12a integrally formed with sides 12b and I2C, respectively. The upper and lower edges of sides 12b and l2care slidably received between the grooves formed by edges 13b-13e. The forwardmost edges of sides 12b and 12C are received within the grooves defined by curve portions l3a,l3a so that when the cover plate 12 is in the fully assembled position, as shown in FIG. l, the housing assembly substantially conceals and seals the components arranged within the interior of the housmg.

A synchronous motor 14, positioned within the housing assembly, is secured to side llc in the manner best shown in FIGS. 2c and 3 by providing

suitable fastening members

15,15 passing through suitable openings in side llc and

spacers

16,16 which fasteners threadedly engage suitable openings provided in the flanged portion.l4a,14a of the motor assembly. A centrally located opening 17 is provided within motor 14 for receiving a bearing assembly 18 in which a first tapered end 19a of shaft 19 is mounted. The synchronous motor is further provided with a plurality of arcuate-shaped projections l4b arranged at spaced intervals around an imaginary circle whose center lies on the longitudinal axis 24. The projections are pole pieces which generate the desired electromagnetic field for rotation of the rotor assembly 26. The projections may be of differing arcuate length and have differing spacings therebetween to produce the desired revolving field. The pole pieces may be of different lengths and spacings. The opposite tapered end l9b of shaft 19 is joumaled within a 6a looking in the bearing assembly which, in turn, is press-tted within a recess 22 provided in triangular-shaped bearing mount 2l, as best shown in FIGS. 2b and 3. The bearing mount 21 is formed from a substantially flat, triangular-shaped plate which is bent or otherwise formed to provide a substantially circular-shaped recess 22 having a small opening 23 whose center lies on the longitudinal axis 24 for shaft 19. The comers 21a-21e of the bearing mount are bent to extend toward the interior surface of side 1lb which is provided with three openings 25a-25C for respectively receiving the bent ends 21a-21e` of lthe bearing mount. The tapers of each of the bent ends act to center the bearing mount relative to the associated openings in face plate l lb.

The rotor assembly 26 for motor 14 is comprised of a central portion 26a (which may be formed of aluminum) having an opening 26b so as to be press-fitted to shift 19. The central portion 26a is secured to an outer ring portion 26C having an outwardly bent cylindrical-shaped flange 26d. The revolving magnetic eld developed by motor 14 reacts with the outer portion 26e` (formed of a suitable ferromagnetic material) causing rotation (at a constant predetermined speed) of rotor assembly 26 which is free to so rotate together with the freewheeling shaft 19.

A magnetic drum assembly 27 is comprised of a central portion 27a having a central opening 27b whose center is coincident with the longitudinal axis 24 of shaft 19. An annularshaped groove or depression 27e` is provided in central portion 27a and is designed so that its surface, which lies furtherest away from the longitudinal axis 24 on the convex side of the depression, makes a firm press-fitting with the interior surface of cylindrical-shaped flange 26d provided in rotor assembly 26. The central opening 27b may also be designed to be pressfitted upon shaft 19. It should be noted that the drum assembly 27 completely surrounds the rotor assembly 26 and further surrounds a portion of synchronous motor 14, thereby greatly reducing the width of the assembly measured along the longitudinal axis 24.

The central portion 27a of the magnetic drum assembly is integrally formed with a cylindrical portion 27d whose exterior surface may be coated in any conventional fashion with a magnetic material capable of being driven by a suitable magnetic recording head into either one of two opposite saturation states. One suitable material which may be employed is a modified gamma iron oxide referred to as MO-9858 and is available from the Charles Pfeizer Company of Easton, Pennsylvania.

Energization of motor 14 generates a revolving magnetic field, causing rotation of rotor assembly 26 due to the magnetic coupling therebetween which, in turn, causes rotation of shaft 19 and magnetic drum assembly 27. The bearing

assemblies

18 and 20 provide for freewheeling mounting of the shaft 19 and further acts to prevent any wobbling or eccentricity in the rotation of

elements

26, 19 and 27.

Surface portion lla of housing ll is provided with a pair of narrow, elongated slots 28a and 28b and a slot 28e located between slots 28a and 28b. A retaining clip 29 (note especially FIG. 2a) is employed for positioning and securing a magnetic head assembly 35 to housing ll, which clip is comprised of a central portion 30 having integrally formed, downwardly and inwardly depending

legs

31 and 32 whose distal ends 31a and 32a, respectively, are bent inwardly in themanner best shown in FIGS. 2b and 4. Central portion 30 is provided with a rectangular-shaped opening 33.

The magnetic head assembly is mounted to housing 1l in the following manner:

Sides

31 and 32 of retainer clip 29 are inserted into the two elongated slots 28a and 28b, respectively. The magnetic head assembly 35 may be positioned against the interior surface of housing side lla so that its connecting terminals 36 are free to pass through the slot 28C in surface 11a. The retainer clip 29 which is formed of a suitable resilient material is then pressed downwardly in the direction shown by arrows 37-37 until the inwardly

bent portions

31a and 32a embrace the diagonally aligned surfaces 35a and 35h of the magnetic head assembly in the manner shown best in FIG. 2b. The central portion 30 of retainer clip 29 is curved, causing the embracing

flanges

31a and 32a to firmly secure the magnetic head assembly 35 in position.

It should be noted that the elongated slots 28a and 28b provide more than sufficient clearance for passage of the sides 3l and 32 of retainer clip 29 therethrough. The magnetic heads 38 can be seen to be positioned to the right of vertical phantom line 39 which coincides with the diameter of magnetic drum assembly 27 and passes through its axis of rotation 24. The clearance of elongated slots 28a and 28b and likewise the clearance of slot 28C allows the magnetic head assembly 35, together with retainer clip 29, to be moved in either of the opposing directions shown by

arrows

39 and 40 in order to adjust the gap between magnetic heads 30 and the magnetically treated surface 27d of magnetic drum assembly 27. The resiliency of retainer clip 29 serves to maintain the alignment of the magnetic head assembly 35 once it is accurately positioned.

It should be noted that if the magnetic drum assembly requires disassembly for inspection, maintenance or other purposes, the removal of the cover plate assembly l2 from the main housing 11 does not in any way affect the relative positioning between the magnetic head assembly 35 and the magnetic drum assembly 27. Removal of the cover plate l2 provides access to interior components along three sides to facilitate inspection and/or maintenance ofthe magnetic drum assembly.

The mounting of the magnetic drum assembly 27 directly upon the rotor assembly 26 so that the

elements

26 and 27 may be considered as one entity, greatly diminishes the overall size of the magnetic drum assembly, eliminates the need for an output shaft coupling the motor to the magnetic drum and further reduces overall size and weight of the assembly. Magnetic drum assemblies of the type described herein which have been produced to date have housing outer dimensions of 2% inches by 2.3 inches by 1.25 inches. As many as seven separate tracks have already been provided on such drum surfaces and additional tracks may be provided by further judicious arrangement of the magnetic head assembly. The dimen sions set forth above are merely exemplary, and it should be noted that further reductions in size are possible, depending only upon the needs of the user.

FIGS. 5a through 5d show another preferred embodiment of the present invention. Memory system 50, shown in this figure, is comprised of a first mounting plate 5l having a plurality of apertures 52 (preferably four in number) for securing a second mounting plate 53 in spaced, parallel fashion thereto. The spaced, parallel alignment of the mounting plates 5l and 52 is achieved by means of a plurality of spacers 54 (shown best in FIG. 5c), each of which is provided with a pair of tapped apertures 54a and 54b. The openings S2 in mounting plate 5l receive a threaded fastener 55 for threadedly engaging the tapped opening 54a of an associated spacer 54. Mounting plate 53 is provided with suitable openings 56 (preferably four in number), each receiving a threaded fastener which threadedly engages the tapped opening 54b of an associated spacer 54. If desired, lockwashers 58 may be provided to maintain the rigid fastening between fasteners 57 and spacers 54.

Mounting plate 5l is further provided with a centrally located opening 59 for receiving a shaft 60 presstitted into the baseplate and thereby prevented from experiencing any rotational movement. A first thrust-washer 6I is mounted upon shaft 60 and is positioned immediately adjacent the lefthand face of baseplate 51 (relative to FIG. 5d). A cylindricalshaped drum member 62 provided with a pair of

sapphire bearings

63 and 64 secured within suitable cavities provided in the cylinder, is mounted upon shaft 60. The centrally located opening 65 of cylinder 62 has an internal diameter which is slightly greater than the outer diameter of shaft 60. A second thrust-washer 66 is positioned upon shaft 60 adjacent the lefthand face of drum 62 relative to FIG. 5d. An interference fit retainer 67 is mounted near the le-hand end of shaft 60 relative to FIG. 5d and provides a slight clearance between the thrust-washer 66 and the sapphire bearing 64 so as to limit the linear movement of drum 62 relative to shaft 60 to a very slight amount while allowing freewheeling rotation of drum 62 upon shaft 60. The sapphire bearings are preferably forcefitted into the cavities provided in drum 62, and thereby act to seal the hollow interior between the outer periphery of shaft 60 and the inner periphery of opening 65. Two or three microdrops of oil placed within this hollow interior region remain captured within the interior space which acts as an oil reservoir for lubrication purposes. The oil captured in this manner will remain therein for the life of the unit.

Drum 62 is provided with a circular-shaped outer periphery 68 having a magnetic coating 69 of substantially uniform thickness deposited thereon. The drums are preferably produced by coating the cylinder surface with a magnetic material. The coating 69 is sheared and trued to be perfectly concentric. The shearing operation is perfonned by a suitable cutting tool on a machine which may be or resemble a lathe. After shearing, the coating 69 is then lapped to provide a perfectly smooth surface of a thickness of the order of l mil. lf desired, a diamond shearing tool may be employed for shearing and truing the magnetic surface to be perfectly concentric and thereby eliminate the need for the lapping operation.

Drum 62 is provided with an annular-shaped cavity 70 along its left-hand surface (relative to FIG. 5d) so as to form a substantially cylindrical portion 71 of reduced diameter relative to the outer diameter of drum 62. Portion 71 is adapted to receive a cylindrical-shaped rotor member 72 having an outwardly projecting flange 73 which is force-fitted upon portion 71 of drum 62.

A motor 73 is mounted within a hollow opening 74 provided in motor mounting plate 53 and is secured thereto by suitable fastening means 75,75. The leads 76 of motor 73 are provided for coupling to a suitable AC power source.

The stator 77 of motor 73 extends outwardly from the motor toward rotor 72, and is provided for developing a moving flux field for rotation of rotor 72. The motor employed herein is a drag cup motor. Energization of the stator sets up a magnetic field which slightly magnetizes amature (i.e. rotor) 72 which then drags around following the rotating flux eld generated by the stator. Since the rotor is force-fitted upon drum 62, both drum 62 and rotor 72 rotate in unison about shaft 60 when motor 73 is energized. It should be noted that no mechanical coupling exists between the shaft 60 and motor 73. Concentricity of the motor stator 77 and rotatable rotor 72, while not absolutely required, is obtainable by judicious location of mounting plate 53 relative to baseplate 51.

Baseplate 51 is further provided with an aperture 78 for receiving elongated pin 79 which is force-f1tted into opening 78. A rigid elongated plate 80, which supports a magnetic head assembly to be more fully described, is provided with an opening 81 for receiving pin 79 which pivotally mounts member 80 to baseplate 51. Member 80 is retained upon pin 79 by means of a retainer clip 82 which substantially prevents any linear movement between pin 79 and member 80.

The right-hand end of member 80, relative to FIG. 5a, is provided with an opening 82 for receiving an elongated threaded member 83 having an outer diameter greater than the inner diameter 82 so as to be freely movable within opening 82. Baseplate 51 is provided with an opening 84 for threadedly engaging the end portion of threaded member 83 which is provided with a head portion 83a for tightening the head mounting assembly for a purpose to be more fully described. The opening 82 in member 80 may either be circular and of an inner diameter substantially greater than the outer diameter of threaded member 83, or may be oval in shape or an elongated slot so as to permit a certain degree of pivotal movement in either of the directions shown by arrow 85 for the purpose of enabling adjustment of the airgap between the magnetic heads and the drum magnetic surface.

Member is provided with a rectangular-shaped slot 86 for receiving a magnetic head assembly 87 which is clamped and thereby rigidly held within slot 86 by means of a strap member 88 rigidly fastened to member 80 by fastening means 89,89.

As shown best in FIG. Sb, the airgap G between magnetic head assembly 87 and magnetic surface 69 is simply and accurately obtained by pivoting the head assembly mounting member 80 about pin 79 until the appropriate signal strength is obtained. As was previously described, the angle through which member 80 may rotate about pin 79 is controlled by the shape of the opening 82 of member 80, which opening is of a configuration sufficient to allow suitable movement of the magnetic head assembly relative to the cooperating magnetic surface 69 to assure a proper airgap setting. Alignment between the magnetic head assembly 87 and the magnetic surface 69 is obtained by precisely positioning the longitudinal axis of pin 79 and shaft 60 through precise location of the

openings

78 and 59 in baseplate 51 respectively receiving pin 79 and shaft 60. Threaded member 83 may be provided with a lockwasher 90 (see FIG. 5c) to indefinitely retain the magnetic head assembly at the proper airgap setting.

The openings 91 in baseplate 5l are employed to mount the memory assembly upon a suitable supporting surface or framework through the use of fastening means and rubber grommets (not shown) to isolate vibration.

FIGS. 6a6d show still another preferred embodiment of the present invention in which the magnetic memory is mounted and effectively sealed within a housing to keep the unit dirt free and further to enable the unit to be utilized as a plugin assembly for applications in which changes in stored contents thereof may be made without performing erasure and write-in operations (i.e., for use, for example, as a read-only" memory). Obviously, the modular plug-in design may also be utilized as memory devices in systems requiring both read-in and read-out capabilities.

The embodiment of FIGS. 6a-6d is comprised of a first housing member 101 having a hollow and relatively shallow interior 102 defined by the base 101a and upwardly extending sidewalls I01d. FIG.- 7 shows a top plan view which may be considered in conjunction with FIGS. 6a-6d for a better understanding of this embodiment.

The base portion 101a of housing member 101 is provided with an opening 103 surrounded by a raised surface area 104. The drum mounting assembly of FIGS. 6a-6d is substantially identical to that shown in FIG. 5d, for example, and therefore like numerals will be designated to identify like components. As was previously described with respect to FIG. 5d, shaft 60 is force-fitted into opening 103 and first supports a washer 6l and drum 62 thereupon. Drum 62 is provided with a pair of jewel bearings, only one of which (bearing 64) is shown in FIG. 6b. A second washer 66 and retainer ring 67 is then mounted upon shaft 60. Obviously, the other detailed features of the drum and its mounting assembly discussed with respect to FIG. 5d may be and preferably are incorporated in the drum and mounting assembly of the embodiment of FIGS. 6a-6d.

The base portion 101a of housing member 101 is further provided with a slightly raised surface area

101b having openings

105 and 106. Opening 105 receives a pin 106 (see FIG. 6c) force-fitted into the opening and pivotally supporting a magnetic head structure which is comprised of a magnetic head assembly 108 mounted within the central portion of a supporting structure 109 having outwardly extending arms l09a and 109b which are joined at their inward ends to the central portion 109e` and integrally joined at their outer ends to hollow cylindrical members 110 and 111 respectively. Pin 106 passes through the hollow opening of cylindrical member 110 and is secured in this position by means of a washer 112 and retainer ring 113. The opposite cylindrical member 111 receives a threaded fastener 112 which threadedly engages a tapped opening 113 in housing base portion I01a. The outer diameter of threaded number 112 is substantially less than the inner diameter of the opening in cylindrical member 111 so as to permit a significant amount of play therebetween for adjustment of the airgap in substantially the identical manner as was described with respect to the magnetic head assembly shown best in FIGS. a and 5b. Thus, by adjusting the assembly for the precise airgap desired and tightening the head 112a of threaded fastener 112, the desired airgap may be maintained indefinitely. Obviously, a lockwasher may be provided between head 112a and the top surface of cylindrical member 1 11. The central portion 109C may be provided with a suitable hollow opening for receiving and positioning the magnetic head assembly 108. The magnetic head assembly 108 may be permanently molded within the support structure 109 or, alternatively, may be fitted within the opening and provided with a clamping bracket in much the same manner as that shown in FIG. 5a with the precise positioning of the clamping bracket being dependent only upon the needs of the user.

FIG. 7 shows the housing member 101 as being provided with a plurality of bosses l 14a-1 14feach of which is provided with a tapped aperture or, alternatively, with an aperture capable of being tapped by means of a self-tapping screw. Each of these bosses are in alignment with associated openings (not shown) provided in a flat board 1 15 which is preferably a board of the printed circuit variety in that it is formed of a suitable insulating material and has conductive areas such as, for example, areas 116 for establishing electrical circuitry and/or connections between and among various components of the memory system. The specific printed circuit configuration may assume any one of a variety of arrangements wherein packaging inner-electrode capacitances and mechanical limitations are usually taken into account in such printed circuit layouts.

Printed circuit board 115 is positioned upon housing 101 as shown in FIGS. 6a6d, and receives a plurality of either threaded fasteners or self-tapping screws 117a-l17f which cooperate with the associated openings in the printed circuit board and the bosses 114a-l l4f respectively, to enable the printed circuit board to be rigidly fastened to housing portion 101 and thereby provide a sealed housing for the components of the memory which is substantially dirt free and is easy to handle, remove, and/or replace from peripheral equipment for reasons which will be described more fully hereinbelow.

Printed circuit board 115 is further provided with an opening of a substantially large diameter for receiving motor 118 which is secured to printed circuit board 115 by fastening means 119a and 119b which extend through openings in flange 118a of motor 118. The opening in printed circuit board 115 provides sufficient clearance for the projection therethrough of the stator assembly 118C, as shown best in FIG. 6b.

The motor 72 is force-fitted upon the drum member 62 in the same manner as was described with respect to FIG. 5d and, in operation, is slightly magnetized upon energization of motor 118 and is then dragged around, following the rotating flux field set up by the motor stator 77.

The adjustment of the airgap between the magnetic head assembly 108 and the drum surface is performed through the use of a separate assembly (not shown in the present application) which is comprised of a motor similar to motor 118 for rotating rotor 72 and drum 62. The leads (not shown) for the magnetic head assembly are coupled into test circuitry for viewing purposes preferably by an oscilloscope, for example, the readout signals while adjusting the airgap dimension. After suitable adjustment, screwhead 112a is tightened and the airgap adjustment is thereby fixed.

After the airgap adjustment is made, the leads of the magnetic head assembly are wired to appropriate conductive surfaces ofthe type shown by numeral 116. Likewise, the leads of motor 118 are wired to appropriate conductive surfaces of the printed circuit board so that all of the input power leads and output signal leads are available along the upper edge of printed circuit board 115 for connection to peripheral circuitry which may be provided with an edge connector 120 shown at the top of FIGS. 6a and 6d. The edge connector 120 may be permanently affixed to the peripheral circuitry which utilizes a memory assembly of the type 100. The memory assembly is extremely advantageous for use in systems in which specific preprogrammed information may be inserted through the insertion of an assembly 100 containing recorded information required for performing the desired program. Programs may be changed by removing one such assembly and replacing it with another. Obviously, the same advantages may be derived in cases where the memory assembly 100 is employed as a memory which is capable of performing erasure and rewriting of data, as well as equipment utilizing assembly 100 as a ready-only memory.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

What is claimed is:

l. A compact magnetic drum assembly comprising:

synchronous motor means for generating a revolving magnetic field;

a rotor assembly adapted to be rotatably driven by said synchronous motor positioned in close proximity thereto;

a magnetic drum assembly comprising a cylindrical member open at one end thereof being firmly secured to said rotor assembly in a manner such that the rotor assembly in a portion of said rotor means lies within the interior of said cylindrical drum;

housing means having a hollow interior for receiving said motor, rotor and drum assembly;

said synchronous motor means being secured to one face of said housing;

a magnetic head assembly;

retainer means secured to said housing for adjustably positioning the magnetic head assembly to said housing in order to provide a predetermined airgap between the surface of said magnetic drum assembly and said magnetic head assembly;

said housing means being comprised of a first housing member and a cover plate;

said housing member being comprised of a substantially flat central portion having first and second integrally formed sides depending therefrom;

the opposite edges of each of said sides being bent to form receiving grooves for slidably receiving said cover plate;

said cover plate being comprised of a flat central portion having first and second sides integrally fonned therewith and depending therefrom, the edges of said first and second sides being adapted to be slidably received by the grooves provided along the marginal edges of the first and second sides of said housing member.

2. The assembly of claim 1 wherein the flat central portion of said housing member is provided with first and second elongated slots and a third rectangular-shaped opening positioned between said first and second elongated slots;

a substantially C-shaped retainer clip having first and second sides depending from and integrally formed with a curved central portion;

said sides of said retainer clip extending through said first and second elongated slots and having inwardly bent flanges at their distal ends for embracing a magnetic head assembly to rigidly secure said magnetic head assembly to said housing member.

3. A magnetic drum assembly comprising:

a first mounting plate;

a shaft having a first end secured to said first plate;

a drum mounted to rotate about said shaft;

a second mounting plate secured to said first mounting plate arranged in spaced parallel fashion thereto with said drum being positioned between said plates;

a motor having means for generating a revolving magnetic field in the region between said plates;

an annular-shaped rotor secured to the face of said drum adjacent said second plate;

said second plate having an opening;

said motor means being mounted to said second plate within said opening and in close proximity to said rotor for rotating the rotor and the drum about said shaft;

a magnetic pattern being provided on the periphery of said drum;

a magnetic head assembly being adjustably secured to said first plate for enabling adjustment of the airgap between said drum periphery and the magnetic head assembly;

the second end of said shaft being positioned a spaced distance away from said motor means and said second plate to enable rotation of said drum and said rotor without the necessity of obtaining critical alignment between said shaft and said motor.

4. The assembly of claim 3 wherein said second plate is a printed circuit board having a plurality of conductive coatings for selectively electrically connecting said motor means and magnetic head assembly thereto;

said printed circuit board having a first end extending beyondthe adjacent end of said first housing member;

said conductive surfaces extending to the first end of said printed circuit board for facilitating releaseable connection to an edge connector assembly.

5. The assembly of claim 3 wherein said magnetic head assembly is comprised of an arm having a first end pivotally mounted to said first mounting plate and having an opening near the second end of said arm;

fastening means passing through said opening for securing said arm to said first mounting plate;

said opening being larger than the diameter of said fastening means for enabling adjustment of said airgap;

a magnetic head structure secured to said arm intermediate the ends thereof.

6. The assembly of claim 3 wherein said motor means is further comprised of' stator means extending toward said drum and surrounding said rotor;

said drum being provided with an annular-shaped cavity surrounding said rotor to provide adequate clearance for said stator means.

7. A magnetic drum assembly comprising:

a first housing member having a hollow interior and being open along one surface thereof;

a shaft having a first end secured to the base of said housing member;

a substantially flat insulating member adapted to fit over the open face of said housing member forming a hollow enclosure;

a drum mounted to rotate about said shaft and positioned within said enclosure;

an annular-shaped rotor being secured to the face of said drum adjacent said insulating member;

said insulating member having an opening;

motor means having means for generating a revolving magnetic field;

said motor means being secured to said insulating member and positioned within said opening in close proximity to said rotor;

a magnetic pattern being provided on the periphery of said a magnetic head assembly being adjustably secured to said first housing member within said enclosure for enabling adjustment of the airgap between said drum periphery and said magnetic head assembly.

8. The assembly of claim 7 wherein said magnetic head assembly is comprised of an arm having a first end pivotally mounted to said housing member and having an opening near the second end of said arm;

fastening means passing through said opening for securing said arm to said first housing member;

a magnetic head structure secured to said arm intermediate the ends thereof.

9. The assembly of claim 7 wherein said motor means is further comprised of stator means extending toward said drum and surroundingsaid rotor' said drum being provided with an annular-shaped cavity surrounding said rotor to provide adequate clearance for said stator means.

10. A magnetic drum memory including a hollow housing;

a cylindrical drum having a shaft supported by a first interior surface of said housing; said drum being rotatably mounted thereto;

the free end of said shaft extending toward a second interior surface parallel to said first interior surface;

a magnetic material being provided on the outer periphery of said drum;

said memory being characterized by providing a motor secured to said second interior surface and positioned to one side of said drum;

said one side of said drum having a cylindrical-shaped recess facing toward said motor;

said motor having a stator for generating a rotating magnetic field at least partially extending into the region of said recess;

an annular-shaped rotor secured to said drum adjacent said recess and lying within the region of said rotating magnetic field for rotating said rotor and said drum in unison;

the free end of said shaft being positioned a spaced distance from said motor and said second surface thereby avoiding the need for accurately and precisely centering said motor relative to said mounting means;

an adjustable magnetic head assembly for selectively writing or reading information in the magnetic material.

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Claims

1. A compact magnetic drum assembly comprising: synchronous motor means for generating a revolving magnetic field; a rotor assembly adapted to be rotatably driven by said synchronous motor positioned in close proximity thereto; a magnetic drum assembly comprising a cylindrical member open at one end thereof being firmly secured to said rotor assembly in a manner such that the rotor assembly in a portion of said rotor means lies within the interior of said cylindrical drum; housing means having a hollow interior for receiving said motor, rotor and drum assembly; said synchronous motor means being secured to one face of said housing; a magnetic head assembly; retainer means secured to said housing for adjustably positioning the magnetic head assembly to said housing in order to provide a predetermined airgap between the surface of said magnetic drum assembly and said magnetic head assembly; said housing means being comprised of a first housing member and a cover plate; said housing member being comprised of a substantially flat central portion having first and second integrally formed sides depending therefrom; the opposite edges of each of said sides being bent to form receiving grooves for slidably receiving said cover plate; said cover plate being comprised of a flat central portion having first and second sides integrally formed therewith and depending therefrom, the edges of said first and second sides being adapted to be slidably received by the grooves provided along the marginal edges of the first and second sides of said housing member.

2. The assembly of claim 1 wherein the flat central portion of said housing member is provided with first and second elongated slots and a third rectangular-shaped opening positioned between said first and second elongated slots; a substantially C-shaped retainer clip having first and second sides depending from and integrally formed with a curved central portion; said sides of said retainer clip extending through said first and second elongated slots and having inwardly bent flanges at their distal ends for embracing a magnetic head assembly to rigidly secure said magnetic head assembly to said housing member.

3. A magnetic drum assembly comprising: a first mounting plate; a shaft having a first end secured to said first plate; a drum mounted to rotate about said shaft; a second mounting plate secured to said first mounting plate arranged in spaced parallel fashion thereto with said drum being positioned between said plates; a motor having means for generating a revolving magnetic field in the region between said plates; an annular-shaped rotor secured to the face of said drum adjacent said second plate; said second plate having an opening; said motor means being mounted to said second plate within said opening and in close proximity to said rotor for rotating the rotor and the drum about said shaft; a magnetic pattern being provided on the periphery of said drum; a magnetic head assembly being adjustably secured to said first plate for enabling adjustment of the airgap between said drum periphery and the magnetic head assembly; the second end of said shaft being positioned a spaced distance away from said motor means and said second plate to enable rotation of said drum and said rotor without the necessity of obtaining critical alignment between said shaft and said Motor.

4. The assembly of claim 3 wherein said second plate is a printed circuit board having a plurality of conductive coatings for selectively electrically connecting said motor means and magnetic head assembly thereto; said printed circuit board having a first end extending beyond the adjacent end of said first housing member; said conductive surfaces extending to the first end of said printed circuit board for facilitating releaseable connection to an edge connector assembly.

5. The assembly of claim 3 wherein said magnetic head assembly is comprised of an arm having a first end pivotally mounted to said first mounting plate and having an opening near the second end of said arm; fastening means passing through said opening for securing said arm to said first mounting plate; said opening being larger than the diameter of said fastening means for enabling adjustment of said airgap; a magnetic head structure secured to said arm intermediate the ends thereof.

6. The assembly of claim 3 wherein said motor means is further comprised of stator means extending toward said drum and surrounding said rotor; said drum being provided with an annular-shaped cavity surrounding said rotor to provide adequate clearance for said stator means.

7. A magnetic drum assembly comprising: a first housing member having a hollow interior and being open along one surface thereof; a shaft having a first end secured to the base of said housing member; a substantially flat insulating member adapted to fit over the open face of said housing member forming a hollow enclosure; a drum mounted to rotate about said shaft and positioned within said enclosure; an annular-shaped rotor being secured to the face of said drum adjacent said insulating member; said insulating member having an opening; motor means having means for generating a revolving magnetic field; said motor means being secured to said insulating member and positioned within said opening in close proximity to said rotor; a magnetic pattern being provided on the periphery of said drum; a magnetic head assembly being adjustably secured to said first housing member within said enclosure for enabling adjustment of the airgap between said drum periphery and said magnetic head assembly.

8. The assembly of claim 7 wherein said magnetic head assembly is comprised of an arm having a first end pivotally mounted to said housing member and having an opening near the second end of said arm; fastening means passing through said opening for securing said arm to said first housing member; said opening being larger than the diameter of said fastening means for enabling adjustment of said airgap; a magnetic head structure secured to said arm intermediate the ends thereof.

9. The assembly of claim 7 wherein said motor means is further comprised of stator means extending toward said drum and surrounding said rotor; said drum being provided with an annular-shaped cavity surrounding said rotor to provide adequate clearance for said stator means.

10. A magnetic drum memory including a hollow housing; a cylindrical drum having a shaft supported by a first interior surface of said housing; said drum being rotatably mounted thereto; the free end of said shaft extending toward a second interior surface parallel to said first interior surface; a magnetic material being provided on the outer periphery of said drum; said memory being characterized by providing a motor secured to said second interior surface and positioned to one side of said drum; said one side of said drum having a cylindrical-shaped recess facing toward said motor; said motor having a stator for generating a rotating magnetic field at least partially extending into the region of said recess; an annular-shaped rotor secured to said drum adjacent said recess and lying within the region of said rotating magnetic field for rotating said rotor and saId drum in unison; the free end of said shaft being positioned a spaced distance from said motor and said second surface thereby avoiding the need for accurately and precisely centering said motor relative to said mounting means; an adjustable magnetic head assembly for selectively writing or reading information in the magnetic material.