Patent GB-1055890-A (GB)
Title: Magnetic devices for use in information handling apparatus
IPC: H03K17/80
Filed: 1963-12-05
Abstract: 1,055,890. Magnetic storage apparatus. RADIO CORPORATION OF AMERICA. Dec. 5, 1963 [Dec. 11, 1962], No. 48154/63. Heading H3B. [Also in Division G4] A storage device for a code converter coinprises a stack of magnetic core laminations each defining a closed magnetic flux path and each being provided with a plurality of apertures, arranged in accordance with a code, certain apertures in the laminations registering with apertures in other laminations of the stack so that current passed through conductors threaded through the aligned apertures selectively change the magnetic state of different ones of the core structures. Each lamination 26 is as shown in Fig. 3 and is provided with a rectangular central opening 28, apertures in the form of notches being provided which extend into the lamination from the opening 28 and the exterior surface. The laminations are arranged in two stacks 34, 36 to form a code conversion device 20 for use in a printer, the laminations being separated by magnetic shields, with the input legs 30 of the laminations facing each other. The apertures in the various laminations are aligned and input, strobe and read-out windings are threaded therethrough as shown, the arrangement being such that if a current is passed through a conductor threaded through an aperture on the inside of the closed flux path the core is saturated whereas if the conductor is threaded through an aperture on the outside the core is not saturated. Signals applied to conductors passing through the inside strobe notches induce by transformer action output signals in conductors which pass through inside read-out notches, if the core is unsaturated. As shown in Fig. 1, the code conversion device is used to operate a printing head 22, e.g. print a character A, Fig. 2 (not shown), the input code for the bits D0 to D5 " 0 " " 0," " 0," " 1," " 0," " 0" being applied to AND gates 10, 12 together with an enable signal to reset all the transistor bi-stable circuits 18 except that connected to the D3 bit. The bi-stable circuits are arranged so that the "1 " output causes a current to flow through input windings, Fig. 4, 50, 54, 58, 62, 66, 70 and a " 0 "output causes current to flow through windings 52, 56, 60, 64, 68, 72 of the three laminations forming the group of "A". Thus the input code for the bits D0, D1, D2, D4, D5 causes current to flow through windings 52, 56, 60, 68, 72 which pass through outside apertures and hence do not saturate the lamination. Similarly the current flowing due to bit D3 flows through winding 62 passing through an outside aperture and has no effect on the magnetic state of the core Hence none of the laminations of the group forming the character A are saturated whereas laminations of the other groups will be since they have different input aperture patterns. A sequence of five strobe pulses is then applied to windings 88, 90, 92, 94, 96 and 88<SP>1</SP>, 90<SP>1</SP>, 92<SP>1</SP>, 94<SP>1</SP>, 96<SP>1</SP>. The first strobe pulse through windings 88, 88<SP>1</SP> results in output signals corresponding to bits R3 to R7 being induced in read-out windings 78 to 86 only, windings 74, 76 passing through outside notches. The output signals R3 to R7 operate the lower five styli of the print head 22 to print five dots in the lower five rows of the first column. A second strobe pulse through windings 90, 90<SP>1</SP> causes signals R2, R4 to be induced between winding 90<SP>1</SP> and read-out windings 76<SP>1</SP>, 80<SP>1</SP> respectively so that the second and fourth styli of the head are driven to print the second column. A lamination (not shown) for the third column is then read out by the third strobe pulse. The fourth and fifth strobe pulses read out the first and second laminations again. After a time delay by circuit 16 the next succeeding character is applied to the AND gates 10, 12. Noise pulses which are induced into the laminations when they change states are cancelled because the read-out windings on the two stacks have an opposite winding sense.