The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 13, 1979
Filed:
Jun. 30, 1977
Mitchell S Cohen, Ossining, NY (US);
Emerson W Pugh, Mt. Kisco, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
These improved current controlled transfer switches are particularly useful for changing the propagation path of very small bubble domains without requiring large amounts of transfer current. The underlying principle is that the transfer operation occurs when the magnitude of the magnetic drive field used to move bubble domains has diminished to a small value, or is zero. This means that the magnetic field due to current in the switch does not have to overcome the effect of the drive field and therefore can be very small while still being effective. This is termed a 'start/stop' operation and in one embodiment, current-assisted transfer is achieved by utilizing a change in the sequence of the magnetic drive field (generally an in-plane rotating field) at the time of transfer. In another embodiment, a continuous 'three-quadrant' magnetic drive field is used instead of the customary 360.degree. rotating drive field. This three-quadrant field cycle is also the normal cycle for bubble storage operations and bubble motion elsewhere in the magnetic circuit is not disturbed by the switching operation because all devices are designed to operate with only one type of drive field cycle, which is the three-quadrant cycle. Switches operating in accordance with these principles do not have to have a particular design; in fact, several different designs are illustrated.