US 4,227,313 AGranted

Compasses

OwnerJohn B. Hennessyinventor

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Abstract

A compass includes a chamber, a card, needle or the like together with suspension means which suspend the card, needle or the like within the chamber. Magnet mounting means are engaged with the card, needle or the like and a magnet is engaged with the magnet mounting means in such a manner that in use the magnet may rotate at least in a plane normal to the plane containing the card, needle or the like, and such movement does not cause any substantial movement of the card, needle or the like.

Claims8

Dependent claims

A compass comprising:

an enclosed chamber;
a flat card, needle or the like positioned within said chamber;
said chamber comprising a cylinder having upper and lower end walls;
pivot suspension means, operably connected between said card, needle or the like and said upper end wall of said cylinder, for allowing said card, needle or the like to pivot within said cylinder about an axis perpendicular to said card, needle or the like;
said chamber containing therein liquid means for floating said card, needle or the like within said cylinder and for causing said card, needle or the like to rise upwardly against said pivot suspension means;
magnet mounting means engaged with and depending from said card, needle or the like within said chamber;
a magnet supported by said magnet mounting means within said chamber in a manner such that in use said magnet is rotatable at least in a plane normal to the plane of said card, needle or the like, such rotation not causing any substantial movement of said card, needle or the like;
said magnet mounting means and said magnet being free of any support from or connection to any walls of said chamber, whereby said card, needle or the like, said magnet mounting means and said magnet are supported within said chamber against said pivot suspension means solely by said liquid means;
said upper and lower end walls of said cylinder being positioned and dimensioned such that in directions normal to the plane of said card, needle or the like there are small clearances between said card, needle or the like and said end walls, whereby said end walls form means for limiting any tilting movement of said card, needle or the like with respect to said axis;
and
said chamber further comprising an extension depending from the mid point of said cylinder, said magnet mounting means extending from said card, needle or the like into said extension, said magnet being pivotally affixed to said magnet mounting means, and the dimension of said extension being such that the diameter of said extension in a plane substantially parallel to the plane of said card, needle or the like is substantially less than the diameter of said cylinder in the plane of said card, needle or the like.

8 more elements

Dependencies are inferred from the claim text.

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Abstract

A compass comprising:

an enclosed chamber;
a flat card, needle or the like positioned within said chamber;
said chamber comprising a cylinder having upper and lower end walls;
pivot suspension means, operably connected between said card, needle or the like and said upper end wall of said cylinder, for allowing said card, needle or the like to pivot within said cylinder about an axis perpendicular to said card, needle or the like;
said chamber containing therein liquid means for floating said card, needle or the like within said cylinder and for causing said card, needle or the like to rise upwardly against said pivot suspension means;
magnet mounting means engaged with and depending from said card, needle or the like within said chamber;
a magnet supported by said magnet mounting means within said chamber in a manner such that in use said magnet is rotatable at least in a plane normal to the plane of said card, needle or the like, such rotation not causing any substantial movement of said card, needle or the like;
said magnet mounting means and said magnet being free of any support from or connection to any walls of said chamber, whereby said card, needle or the like, said magnet mounting means and said magnet are supported within said chamber against said pivot suspension means solely by said liquid means;
said upper and lower end walls of said cylinder being positioned and dimensioned such that in directions normal to the plane of said card, needle or the like there are small clearances between said card, needle or the like and said end walls, whereby said end walls form means for limiting any tilting movement of said card, needle or the like with respect to said axis;
and
said chamber further comprising an extension depending from the mid point of said cylinder, said magnet mounting means extending from said card, needle or the like into said extension, said magnet being pivotally affixed to said magnet mounting means, and the dimension of said extension being such that the diameter of said extension in a plane substantially parallel to the plane of said card, needle or the like is substantially less than the diameter of said cylinder in the plane of said card, needle or the like.

8 more elements