Magnetic anchoring apparatus

• US 4,090,162 A
• Filed: 10/14/1975
• Issued: 05/16/1978
• Est. Priority Date: 10/16/1974
• Status: Expired due to Term

• Current Assignee: Angelo Grandini, Bruno Zaramella, Michele Cardone
• Original Assignee: Angelo Grandini, Bruno Zaramella, Michele Cardone
• Inventors: Cardone, Michele, Grandini, Angelo, Zaramella, Bruno
• Primary Examiner(s): Harris, George
• Application Number:
  US05/622,369
• Time in Patent Office: 945 Days
• Field of Search: 335/289, 335/290, 335/291, 335/294, 335/295, 335/284
• US Class Current: 335/289
• CPC Class Codes: B23Q 3/1546 using permanent magnets
• CPC Class Codes: H01F 2007/208 combined with permanent magnets
• CPC Class Codes: H01F 7/04 Means for releasing the attractive force

Abstract

Magnetic apparatus for securing ferromagnetic pieces to lifting equipment, conveying devices and machine tools. The apparatus comprises a first nonreversible magnetopermanent core; a second reversible magnetopermanent core coacting with the former on a same magnetic yoke defining part of the work securing surface, and a solenoid wound about said reversible core and supplied with direct current in either direction for a period of time sufficient to cause said reversible core to follow a portion of the hysterisis loop thereof to generate an electromagnetic field for inverting the polarization of said core, thus enabling respective activation or deactivation of the work securing surface.

Claims

1. Magnetic apparatus for holding ferromagnetic pieces, comprising:

magnetopermanent cores defining a magnetic circuit having a work surface and including a first non-reversible magnetopermanent core of an anisotropic ceramic type material, a second reversible magnetopermanent core member of a melted type anisotropic material having a magnetic remanence greater than twice the magnetic remanence of said first core and a coercitivity less than one-third of said first core;

a magnetic yoke defining part of said work surface and coacting with said first and second magnetopermanent cores;

a polarization inverting solenoid surrounding said second reversible core for generating electromagnetic fields for inverting the polarization of said second core and respectively activating or deactivating said work surface;

said non-reversible core is interposed between said yoke and an indirect induction polar element to form a direct induction polar element, said first non-reversible core having a direction of magnetization perpendicular to said polar elements;

said second reversible core member is aligned with said yoke and has a direction of magnetization perpendicular to said first non-reversible core; and

further comprising a ferromagnetic crown common to said polar elements and opposite said work surface.

2. Magnetic apparatus for holding ferromagnetic pieces, comprising:

magnetopermanent cores defining a magnetic circuit having a work surface and including a first non-reversible magnetopermanent core of an anisotropic ceramic type material, and a second reversible magnetopermanent core member of a melted type of anisotropic material having a magnetic remanence greater than twice the magnetic remanence of said first core and a coercitivity less than one-third of said first core;

a magnetic yoke defining part of said work surface and coacting with said first and second magnetopermanent cores;

a polarization inverting solenoid surrounding said second reversible core for generating electromagnetic fields for inverting the polarization of said second core and respectively activating and deactivating said work surface;

said second reversible core is aligned with and has a direction of magnetization parallel to said yoke and including two non-reversible cores opposite said yoke and positioned between the latter and an associated indirect induction polar element; and

said two non-reversible cores being arranged against said yoke with respective directions of polarization opposite to one another and perpendicular to the latter; and

further comprising a ferromagnetic crown opposite said work surface.

3. Magnetic apparatus for holding ferromagnetic pieces, comprising:

magnetopermanent cores defining a magnetic circuit having a work surface and including a first non-reversible magnetopermanent core of an anisotropic ceramic type material, and a second reversible magnetopermanent core member of a melted type anisotropic material having a magnetic remanence greater than twice the magnetic remanence of said first core and a coercitivity less than one-third of said first core;

a magnetic yoke defining part of said work surface and coacting with said first and second magnetopermanent cores;

a polarization solenoid surrounding said reversible core for generating electromagnetic fields for inverting the polarization of said second core and respectively activating or deactivating said work surface;

a plurality of first polar elements spaced apart from one another;

a ferromagnetic support common to said first polar elements;

a plurality of second polar elements alternately interposed between said first polar elements and defining slots parallel to one another, each defining a common magnetic yoke;

said reversible core member being surrounded by a respective inverting electromagnet and arranged between each of said second polar elements and said ferromagnetic support;

said non-reversible core arranged in each of said slots with a polarization direction perpendicular to said polar elements thereby defining a work surface activated by polar elements alternately of opposite polarity;

said polar elements and said reversible core member being secured by fastening screws; and

spacers of paramagnetic material being superimposed with respect to said non-reversible core member and locked by a transverse tie-rod.

4. An apparatus according to claim 3, wherein said polar elements extend beyond said non-reversible core member to the apparatus work surface.

5. An apparatus according to claim 3, wherein the empty spaces between the parts comprising the apparatus are filled with an epoxy resin.