US3872454A

US3872454A - Skewed core matrix

Info

Publication number: US3872454A
Application number: US424296A
Authority: US
Inventors: Michael F Boice; Niels Krag
Original assignee: Electronic Memories and Magnetics Corp
Current assignee: Electronic Memories and Magnetics Corp
Priority date: 1973-12-13
Filing date: 1973-12-13
Publication date: 1975-03-18
Anticipated expiration: 1992-03-18

Abstract

A magnetic core memory of the type that has ring-shaped cores arranged in columns and rows and strung with wires along the axes of the columns and rows, wherein the axes of the columns are oriented at an angle of less than 90* with respect to the axes of the rows to thereby increase the width of the ''''stringing window'''' so that wires can be more easily strung through the cores. A preferred array has column axes oriented at approximately 77* from the row axes.

Description

United States Patent Boice et al.

[ Mar. 18, 1975 SKEWED CORE MATRIX inventors: Michael F. Boice, Torrance; Niels Krag, Pacific Palisades, both of Calif.

Electronics Memories & Magnetics Corporation, Hawthorne, Calif.

Filed: Dec. 13, 1973 Appl. No.: 424,296

Assignee:

Us c1. 340/174 M, 29/604 1111. c1 011C 5/02, G110 11/06 Field of Search 340/174 M, 174 MA; 29/ 04 References Cited UNITED STATES PATENTS H1966 Gutwinetal..... ..340/174MA 1/1973 Sell et al. 340/174 M FOREIGN PATENTS OR APPLICATIONS 275,140 0/1970 U.S.S.R. 340/174 M Primary Examiner-James W. Moffitt Attorney, Agent, or F irm Lindenberg, Freilich, Wasserinan Ros en & Fernandez 57 ABSTRACT A magnetic core memory of the type that has ringshaped cores arranged in columns and rows and strung with wires along the axes of the columns and rows,

wherein the axes of the columns are oriented at an angle of less than 90 with respect. to the axes of the rows to thereby increase the width of the stringing window so that wires can be more easily strung through the cores. A preferred array has column axes oriented at approximately 77 from the row axes.

4 Claims, 6 Drawing Figures SKEWED CORE MATRIX BACKGROUND OF THE INVENTION This invention relates to magnetic core arrays, and more particularly to an arrangement of the cores in such arrays.

Magnetic core memories commonly utilize large numbers of ring-shaped cores arranged in rectangular arrays and strung with wires along the axes of the rows and columns. High capacity memories of small size and cost are produced by utilizing large numbers of very small cores, a typical memory section including many thousands of cores arranged on a substrate. The use of small cores gives rise to problems in stringing wires through them. Some of the smaller cores may have an outside diameter such as 14 mils (thousandths of an inch), a hole diameter of 8 mils, and a thickness of 4 mils. With such a core oriented at 45 to the row and column axes, the stringing window or opening as viewed along either axis, may be less than threethousandths inch. Such a small stringing window hampers the stringing of wires through the cores, inasmuch as the smallest available and practical needles utilized to project wires through cores are'three-thousandths inch in diameter. Needles smaller than this are hard to procure and furthermore they become damaged very easily. Also, two wires are often strung along the column axes, and it is often desirable to utilize large gauge wires, so that a large stringing window along at least one axis is very desirable. The problem of stringing the wires and accommodating large gauge wires is further compounded in the case of certain cores which are unusually thick. A core array design which enlarged the stringing window to facilitate the stringing of wires and to permit the accommodation of larger diameter wires,

would facilitate the production of high density core arrays.

SUMMARY OF THE INVENTION on a substrate, in substantially straight rows and columns, and with wires extending through the cores along the axes of the rows and columns. The axes of the columns are oriented at an angle of less than 90 to the axes of the rows in order to enlarge the stringing window along the axes of the columns, so that the column wires are more easily projected through the cores and so that larger diameter wires can be utilized.

In one core array, the cores are oriented at slightly more than the conventional 45 to the row axes to slightly widen the stringing window along the row axes, eventhough this slightly decreases the stringing window along the column axes. However, the column axes are oriented at approximately 77 to the row axes, instead of the conventional 90. This results in a very large increase in the stringing window along the column axes, so that large diameter wires can be strung therealong to increase the speed of the memory. The use of an angle of approximately 77 results in only a moderate increase of the core spacing and overall array size, while providing a very large increase in the size of the stringing window along the column axes.

best be understood from the following description when read in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial perspective view of a magnetic core memory constructed in accordance with the invention; FIG. 2 is a plan view of a portion of the array of FIG.

FIG. 3 is a greatly enlarged partial sectional top view of another array constructed in accordance with the invention, wherein a thick core is utilized;

FIG. 4 is a plan view of the entire array of FIG. 1;

FIG. 5 is a greatly enlarged partial sectional top view showing one core of the array of FIG. 2; and

FIG. 6 is a plan view of a portion of an array constructed in accordance with another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a magnetic core memory 10 which includes a support or substrate 12 of insulative material with an array 14 of ring-shaped magnetic core 16 positioned on the substrate. A group of row wires 18 extends through the cores along the row axes 20, while a group of column wires 22 extend through the cores along the column axes 24. FIG. 2 illustrates the orientation of the cores as seen in a plan view. In a conventional core array, the axes of the columns and. rows are oriented at to one another so that the row and column wires extend at 90 (although an additional wire may be utilized which may extend at 45 to the row and column axes). However, in accordance with the present invention, the row and

column axes

20, 24 are oriented at an angle C which is less than 90 and more than 45.

The memory 10 is constructed by first mounting the cores on the substrate 12, and then stringing wires through the cores. One row wire 18'may be strung through each row of cores, and then one or two column wires may be strung through each column of cores. Both stringing processes are difficult, but the stringing of the column wires may be especially difficultbecause the holes of the cores are already partially occupied by the row wires. The stringing is typically accomplished by welding the front end of each wire to the rear end of a needle and projecting the needle through the row or column of cores, so that the needle can then be pulled to draw the wire through the cores. The stringing window or width of the path along which the needle must move is typically very small. FIG. 2shows the width W, along the row direction and the width W along the column direction. The cores are oriented at an angle A of approximately 45 with respect to the row axes, to provide a considerable width of stringing window along both the column and row axes. If each column axis 24 were at 90 to each row axis 20, then the stringing windows would be the same in both directions, and both stringing windows would be small. However, by angling the column axis 24 at an angle B of at least a few degrees away from the perpendicular, a greatly increased column stringing window is obtained.

An understanding of the magnitude of the advantage gained by utilizing column axes oriented at less than 90from the row axes, can be gained by considering the increase in the stringing window, for a typical kind of core array. FIG. 5 illustrates a portion of an

array utilizing cores

16a, 16b, 16c which are of the typical smaller size which has an outer diameter D, of 14.5 mils (thousandths of an inch), an inner or hole diameter D, of 8 mils, and a thickness T of 4 mils. The angle A of the core orientation with respect to the row axis 20 is 46. For a prior art typical array wherein an angle A of 45 is utilized, the width W, of the row stringing window is slightly less than 3 mils. As a result, difficulty may be experienced in projecting a needle of 3 mils diameter through the row of cores when stringing the row wires. By increasing the angle A to 46, a stringing window width of slightly more than 3 mils is obtained, which facilitates the projection of a standard 3 mil needle through the rows of cores.

In a prior art array, a core adjacent to core 16a in the same column, would be at the position 16b wherein the center b of one core was directly under the center 30a of the other core, so that the column axis at 24: would be at 90 to the row axis 20. As a result, the width W, of the column stringing window would be less than 3 mils, so that the stringing of column wires could not be managed, especially if the row wires had been already strung. However, by utilizing column axes at angles of less than 90, alarger column stringing window is obtained, which not only facilitates the stringing of the column wires, but which permits multiple large diameter wires to be utilized along the column axes.

One choice of column axis 24w employs an angle of 77 from the row axis 20. For this angle, the center of the adjacent core 16b is moved from the position 30b to the position 30w. This direction of core movement is required because it insures that the adjacent core 16c of the same row as core 16b will remain clear of the core 16a, the direction of movement being along the axis of the hole of the core 16b. With the core 16b moved so its center is at the position 30w, a large increase in the column stringing width is obtained, the stringing window increasing from about 2.8 mils to 4.7 mils, or in other words increasing by about 70%. This much larger stringing window facilitates the stringing of column wires through cores which have already been strung with row wires, and also permits the use of larger gauge wires along the column direction.

The movement of the center of core 16b from the position 30b involves an increase in the vertical spacing S, of the cores in a direction perpendicular to the row axis 20. However, a substantial vertical spacing isnecessary to keep the row stringing windows clear of interference from the cores lying in adjacent rows. For example, if the core 16b is positioned with its center at 30b, row wires cannot be strung through the core 16b v because of interference from the bottom of the core 16a. A downward movement, to at least the position 30w, is required to eliminate such interference with row stringing. Thus, an angle of approximately 77 really does not add to the required vertical spacing of the cores, and yet it results in a greatly increased width of column stringing window. A further slight decrease in the angle C of the column axis to about 70, at the orito 5.6 mil, or in other words about 20%. The vertical spacing S undergoes an increasefrom about 8.5 mils to 10.1 mils or about 20%. A still further decrease below 70, in the angle C of the column axis with respect to the row axis, is normally not desirable. A further decrease to 65 as indicated by the line 242, results in an increase of the column stringing window to 6.2 mils, or in other words about 30% as compared to the stringing window at 77. However, the vertical spacing increases to about 12.1 mils or about 40% as compared to the angle of 77. An angle between 77 and 90 can be utilized, although there is no advantage to that in the case of the cores of the dimensions shown in FIG. 5. At an angle C of 85, as represented by the line 24a, the column stringing window is about 3.6 mils, which is about halfway between the stringing window width obtained for 90' and 77.

The use of column axes angled at less than 90 to the row axes results in an increase in the size of the entire array, where the array is mounted on a rectangular substrate, as shown in FIG. 4. This is because the angling of less than 90 results in a horizontal shift between the uppermost and lowermost row of cores. However, the amount of increase is generally not prohibitive, and it is often possible to utilize the areas at 40 and 42, which are not occupied by cores, to hold other components which must be'mounted on the substrate.

Magnetic cores are produced in a variety of sizes, although the most common sizes commercially used in magnetic core arrays normally range from about 14 mils to about 30 mils in outside diameter. The most common type of binary core has relative dimensions of the type illustrated for the core of FIG. 5, with an outer diameter D, of about 14 times a unit length, and an inside diameter D, about eight times the unit length, and a thickness T about four times the unit length, the unit length used in the example described earlier herein being 1 mil. Thus, for a core of about 30 mil outside diameter, a typical inside diameter is about 16 mils and a typical thickness is about 8 mils. Cores have been recently developed which can be utilized in more than two different states, and these multi-state cores have a somewhat greater thickness in relation to their outside and inside diameters than the cores of FIG. 5. The increased thickness of such cores results in a smaller stringing window for a given orientation of the cores. However, by skewing the array so that the orientation of the column axes are at less than 90 to the row axes, a great increase in the column stringing window is obtained.

FIG. 3 illustrates cores 50a,- 50b which have a thick ness dimension T about 50% greater than for the cores of FIG. 5, in relation to the inside and outside diameters. Thus, for a 30 mil outside diameter and 16 mil inside diameter core, the thickness T,,, is about 12 mils instead of 8 mils. The stringing window is about 2.8

entation of line 24y, can be utilized to obtain a moderate increase in the column stringing window at the cost of a moderate increase in the vertical spacing. With the center of the core 16b moved from the position 30w to 30y, the stringing window increases .from about 4.7 mil mils along a column axis 52 at an angle C of 90 from the row axes 54. For such a core, a substantial increase in the stringing window along both the row and column axes may be required. This can be achieved by increasing the core orientation angle A from 45 to 50, to increase the row stringing window to about 4.4 mils, and by decreasing the column angle from 90 to about to obtain an 8 mil column stringing window for this core orientation.

Thus, the invention provides an arrangement for an array of magnetic cores, which facilitates the stringing of wires through the cores and which enables the use of larger diameter wires. This is accomplished by orienting the columns of the array of less than 90 to the axes of the rows. For a typical binary core, a column axis at about 77 (i.e., between 75 and 80) with respect to the row axis provides a maximum increase in column stringing window width, with little if any increase in required vertical spacing of the cores. A rotation of the column axes away from the 90 or perpendicular direction should be at least a few degrees. A ro-- tation of more than about (to an angle C of 70) is normally not necessary where the core is oriented at about 45 from the row axis. A rotation of the column axes through much less than 70 normally is not useful because the cores then interfere greatly with one another unless the spacing of the cores is greatly increased. A larger increase in the spacing of the coreswill defeat the major purpose of the rotation, which is to obtain a large stringing window while maintaining a small size of core array. The theoretical lower limit of the angle C is 45, at which the stringing-window is a maximum and equal to the diameter of the hole in the core, but in which the required spacing of the cores increases without limit. Of course, the cores can be oriented in the manner shown in FIG. 6, in which case the angle C is taken as illustrated in that Figure between the

axes

50 and 52.

Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art and consequently it is intended that the claims be interpreted to cover such a plurality of magnetic cores arranged in substantially straight rows and columns on the support, with the axes of the columns oriented at an angle less than 90 and more than 45 to the axes of the rows, each core having a hole and each core oriented with the axis of its hole angled at least several degrees from both the column axis and from the row axis on which the core lies; and

a plurality of wires extending through the cores along the axes of the rows and along the axes of the columns.

2. A magnetic core memory comprising:

a support;

a plurality of magnetic cores arranged in substantially straight rows and columns on the support, with the axes of the columns oriented at an angle of between 70 and 85 to the axes of the rows; and

,3. In a magnetic core memory which includes ringshaped cores arranged in substantially straight rows and columns on a support, and in which wires are strung through the cores along the axes of the rows and columns, and in which each core has an outer diameter of approximately 14 units, a hole diameter of approximately 8 units, and a thickness of approximately 4 units, wherein said unit is a linear dimension fixed for the array, the improvement wherein:

the axes of the columns are oriented at 'an angle B with respect to the axes of the rows, where B is between 70 and 85, whereby to greatly increase the stringing window while minimizing the increase in the size of the array. 7

4. In a magnetic core memory which includes ringshaped cores arranged in substantially straight rows and columns on a support with the cores angled approximately from the row axes, and in which wires are strung through the cores along the axes of the rows andcolumns, and in which each core has an outer diameter of approximately 14 units, a hole diameter of approximately 8 units, and a thickness of approximately 4 units, wherein said unit is a linear dimension fixed for the array, the improvement wherein:

the axes of the columns are oriented at an angle of 77 with respect to the axes of the rows.

Claims

1. A magnetic core memory comprising: a support; a plurality of magnetic cores arranged in substantially straight rows and columns on the support, with the axes of the columns oriented at an angle less than 90* and more than 45* to the axes of the rows, each core having a hole and each core oriented with the axis of its hole angled at least several degrees from both the column axis and from the row axis on which the core lies; and a plurality of wires extending through the cores along the axes of the rows and along the axes of the columns.

2. A magnetic core memory comprising: a support; a plurality of magnetic cores arranged in substantially straight rows and columns on the support, with the axes of the columns oriented at an angle of between 70* and 85* to the axes of the rows; and a plurality of wires extending through the cores along the axes of the rows and along the axes of the columns.

3. In a magnetic core memory which includes ring-shaped cores arranged in substantially straight rows and columns on a support, and in which wires are strung through the cores along the axes of the rows and columns, and in which each core has an outer diameter of approximately 14 units, a hole diameter of approximately 8 units, and a thickness of approximately 4 units, wherein said unit is a linear dimension fixed for the array, the improvement wherein: the axes of the columns are oriented at an angle B with respect to the axes of the rows, where B is between 70* and 85*, whereby to greatly increase the stringing window while minimizing the increase in the size of the array.

4. In a magnetic core memory which includes ring-shaped cores arranged in substantially straight rows and columns on a support with the cores angled approximately 45* from the row axes, and in which wires are strung through the cores along the axes of the rows and columns, and in which each core has an outer diameter of approximately 14 units, a hole diameter of approximately 8 units, and a thickness of approximately 4 units, wherein said unit is a linear dimension fixed for the array, the improvement wherein: the axes of the columns are oriented at an angle of 77* with respect to the axes of the rows.