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US 4,048,851 AGranted
Axial and annular magneto-elastic dynamometers
AssigneeSoletanche
InventorJean Louis Portier
Life of this patent
Estimating the term…
Abstract
An apparatus and method for measuring stresses or forces by measurement of variations of the magnetic properties of ferromagnetic substances under stress conditions. This is carried out by providing a ring of ferromagnetic material between two parallel faces on or between which the stresses are exerted, the ring defining a magnetic circuit, providing an electric coil within and around the ring, passing a current through the coil and measuring changes in the properties of the current to measure variations in the magnetic properties of the ring.
Claims12
A stress measuring device, comprising:
- a plurality of U-shaped pieces joined together to form a ferro-magnetic core having an uninterrupted annular cylindrical shape, each U-shaped piece having a base portion and a pair of leg portions extending from said base portion, adjacent ones of said U-shaped pieces being located with respect to each other such that the base portion of one U-shaped piece lies adjacent the open end of the next adjacent U-shaped piece said adjacent U-shaped pieces together defining a central annular duct within said core;
- and
- means for detecting a compressive stress axially applied to said ferro-magnetic core, comprising an electric winding located in said annular duct in the form of a ring substantially surrounded by said core such that two ends of said winding comprising electrical leads extend out from said duct through an opening in a wall of said core.
A stress measuring device, comprising:
- a ferro-magnetic core having an uninterrupted annular cylindrical shape;
- an annular duct formed in said core, said duct having a substantially rectangular cross-section, the interior walls of said core defining said duct being substantially parallel with corresponding outer walls of said core;
- a pair of annular recesses formed in top and bottom outer walls of said core, each of said recesses being defined by radially inner and outer upstanding leg portions of said core such that a compressive force applied to said device is exerted substantially exclusively on said upstanding leg portions, said recesses having a width substantially the same as the width of said annular duct;
- means for detecting said compressive force axially applied to said ferro-magnetic core, comprising an electric winding located in said annular duct in the form of a ring substantially surrounded by said core, such that two ends of said winding comprising electrical leads extend out from said duct through an opening in a wall of said core;
- and
- an annular resilient ring located in each of said recesses.
3 more elements
A stress measuring device, comprising:
- a ferro-magnetic core having an uninterrupted annular cylindrical shape;
- an annular duct formed in said core, said duct having a substantially rectangular cross-section the interior walls of said core defining said duct being substantially parallel with corresponding outer walls of said core;
- means for detecting a compressive force axially applied to said ferro-magnetic core, comprising an electric winding embedded in an insulating material in said annular duct in the form of a ring substantially surrounded by said core, such that two ends of said winding comprising electrical leads extend out from said duct and through an opening in a wall of said core, said winding and insulating material being spaced from one interior wall of said core lying substantially parallel to an outer wall thereof to which said axial compressive force is applied;
- and
- a resilient ring located in the space between said winding and said one interior core wall to substantially prevent compression of said winding and insulating material when said axial compressive force is applied.
2 more elements
A stress measuring device, comprising:
- a ferro-magnetic core having an uninterrupted annular cylindrical shape;
- a plurality of through holes formed in and extending between parallel inner and outer axial walls of said core, wherein all of said through holes lie in a single plane between and substantially parallel to two axially opposite end faces of said core which define the load bearing faces of said core;
- and
- means for detecting a compressive force axially applied to said ferro-magnetic core, comprising an electrical winding composed of at least one conductor threaded through said holes in said axial walls of said core.
1 more element
A stress measuring device, comprising:
- a ferro-magnetic core having an uninterrupted annular cylindrical shape, said core having axially opposed end faces defining the load bearing surfaces of said core;
- beadings extending axially from said end faces, said beadings containing means for securing said measuring device to a force transmitting member;
- a first set of through holes extending axially between said end faces in a first circumferential plane lying radially outward of said beadins;
- a second set of through holes extending axially between said end faces in a second circumferential plane lying radially inward of said headings;
- and
- means for detecting a compressive force applied to said load bearing end faces, said means comprising an electrical winding composed of at least one conductor threaded through said axially extending holes.
3 more elements
Dependencies are inferred from the claim text.