Magnetic latch mechanism and method particularly for linear and rotatable brakes

The method of selectively and alternatively magnetically latching and unlatching a first member to and from a second member and magnetically unlatching and latching the first member to a third member, said method comprising the steps of:

• (1) providing a magnetic-flux-conductive part of the second member;
• (2) establishing a permanent magnetic flux within a part of the third member;
• (3) magnetically latching the first member to the third member by only the permanent magnetic flux within a part of the first member;
• (4) selectively establishing an electromagnetic magnetic flux within a part of the first member which when established is in magnetic flux interactive relation with the permanent magnetic flux, the electromagnetic flux when established being of predetermined magnetic polar orientations;
• (5) the electromagnetic magnetic flux, when having the predetermined magnetic polar orientations established, modifying the effect of the permanent magnetic flux so the net effective magnetic flux magnetically decreases the magnetic attraction of the first member to the third member;
• (6) then further modifying the effect of the permanent magnetic flux by the electromagnetic flux so the net effective magnetic flux is such that the magnetic attraction of the first member to the third member is eliminated, causing the first member to be magnetically unlatched from the third member, and moving the first member into magnetic latching engagement with said second member;
• (7) then maintaining sufficient electromagnetic flux within the part of the first member to keep the first member magnetically latched to the second member;
• (8) generating a signal in response to a requirement that the first member be magnetically unlatched from the second member and be magnetically latched to the third member;
• (9) and disestablishing the electromagnetic flux and reestablishing the permanent magnetic flux as the only active magnetic flux and moving the first member by magnetic force generated only by the permanent magnetic flux into magnetic latching engagement with the third member and completing a magnetic flux circuit for the permanent magnetic flux through the magnetic-flux-conductive part of the third member and the part of the first member in which the permanent magnetic flux is established.

The method of selectively and alternatively magnetically latching and unlatching a first member to and from braking relation with a second member and magnetically unlatching and latching the first member to and from braking relation with a third member, and controllably decreasing the magnetic latching of the first member to the third member thereby decreasing the braking relation between the first member and the third member, said method comprising the steps of:

• (1) providing a magnetic-flux-conductive part of the second member;
• (2) establishing a permanent magnetic flux within a part of the third member;
• (3) magnetically latching the first member to the third member by only the permanent magnetic flux within a part of the first member;
• (4) selectively establishing an electromagnetic flux within a part of the first member which has two modes of establishment, one of which is by full energization of electromagnets in the first member causing immediate unlatching of the first member with the third member and movement of the first member into magnetic latching engagement with the second member, and the other of which is by incremental energization of electromagnets in the first member, decreasing the magnetic latching of the first member with the third member only until the braking action between the first and third members is such that braking still occurs but movement between the first and the third members which was totally braked is controlled in small increments until the first member reaches a desired position with respect to the third member;
• and
• (5) when the second mode of establishment is practiced, deenergizing the electromagnets and again fully establishing the braking relation between the first and third members, repeating step (3);
• (6) and when the first mode of establishment is practiced, (7) selectively establishing an electromagnetic magnetic flux within a part of the first member which when established is in magnetic flux interactive relation with the permanent magnetic flux, the electromagnetic flux when established being of predetermined magnetic polar orientations;
• (8) the electromagnetic magnetic flux, when having the predetermined magnetic polar orientations established, modifying the effect of the permanent magnetic flux so the net effective magnetic flux magnetically decreases the magnetic attraction of the first member to the third member;
• (9) then further modifying the effect of the permanent magnetic flux by the electromagnetic flux so the net effective magnetic flux is such that the magnetic attraction of the first member to the third member is eliminated, causing the first member to be magnetically unlatched from the third member, and moving the first member into magnetic latching engagement with said second member;
• (10) then maintaining sufficient electromagnetic flux within the part of the first member to keep the first member magnetically latched to the second member;
• (11) generating a signal in response to a requirement that the first member be magnetically unlatched from the second member and be magnetically latched to the third member;
• (12) and disestablishing the electromagnetic flux and reestablishing the permanent magnetic flux as the only active magnetic flux and moving the first member by magnetic force generated only by the permanent magnetic flux into magnetic latching engagement with the third member and completing a magnetic flux circuit for the permanent magnetic flux through the magnetic-flux-conductive part of the third member and the part of the first member in which the permanent magnetic flux is established.