Magnetic friction device

Claim 2

Apparatus for x-ray examination of a body that is supported in a predetermined position including an x-ray source operative to project a beam of radiation into said body, support means, and image receptor means for receiving the x-ray image emergent from said body, and improved means for mounting said receptor means to said support means in a manner that lets said receptor means be moved relative to the support means and x-ray source by applying a predetermined force and that holds said receptor means in a fixed position when said force is discontinued, comprising: one member coupled to said receptor means and another member coupled to said support means, means for holding said members in proximity with each other with a gap between them and permitting one member to move in parallelism with the other, one of said members having a planar surface defined by a magnetic material, the other member having a surface defined by a nonmagnetic material and having a recess presented toward the planar surface of the magnetic material, a permanent magnet element having a planar surface and being contained in the recess of the nonmagnetic material, said element being movable in a direction perpendicular to its planar surface for being attracted to the magnetic surface to develoop a frictional force that must be overcome to move one member relative to the other, said magnet element being comprised of a polymer containing magnetized particles.

Claim 3

The apparatus according to claim 1 wherein the polymer comprising the magnet element is vinyl.

Claim 6

The apparatus according to claim 4 wherein said antifriction bearing elements are composed of nylon.

Claim 8

In combination with x-ray apparatus wherein a body to be examined is supported on a substantially horizontal plane between a radiographic film changer and an x-ray source that projects a beam through said body to the film changer, and the film changer is mounted to an arm that is supported for swinging through an arc about a horizontal axis that is generally parallel to the x-ray beam path, improved means for mounting said film changer to said arm in a manner that permits rotating it to a predetermined attitude relative to said horizontal plane to compensate for changes in its attitude resulting from swinging through an arc where said mounting means provides for holding said film changer in said attitude when said force is discontinued, said mounting means comprising: one member having a planar surface and coupled to said film changer and another member having a planar surface and coupled to said arm, means for holding said members in proximity with each other with a gap between them while permitting one member to rotate in parallelism with the other, the one member being comprised of magnetic material and the other member being comprised of nonmagnetic material and having a recess presented toward the surface of the magnetic material, a permanent magnet element having a planar surface and contained in the recess, said element being movable in a direction perpendicular to its surface for being attracted to the magnetic surface to develop a frinctional force that holds the members in a fixed relationship and which force must be overcome by said predetermined force to cause rotation, said magnet element being comprised of a polymer containing magnetized particles.

Claim 9

In combination with x-ray apparatus wherein a body to be examined is supported on a substantially horizontal plane between a radiographic film changer and an x-ray source that projects a beam through said body to the film changer, and the film changer is mounted to an arm that is supported for swinging through an arc about a horizontal axis that is generally parallel to the x-ray beam path, improved means for mounting said film changer to said arm in a manner that permits rotating it to a predetermined attitude relative to said horizontal plane to compensate for changes in its attitude resulting from swinging through an arc where said mounting means provides for holding said film changer in said attitude when said force is discontinued, said mounting means comprising: one member having a planar surface and coupled to said film changer and another member having a planar surface and coupled to said arm, means for holding said members in proximity with each other with a gap between them while permitting one member to rotate in parallelism with the other, the one member being comprised of magnetic material and the other member being comprised of nonmagnetic material and having a recess presented toward the surface of the magnetic material, a permanent magnet element having a planar surface and contained in the recess, said element being movable in a direction perpendicular to its surface for being attracted to the magnetic surface to develop a frinctional force that holds the members in a fixed relationship and which force must be overcome by said predetermined force to cause rotation, said magnet element being comprised of a polymer containing magnetized particles.

Claim 10

The apparatus according to claim 7 wherein said polymer is vinyl.

Claim 13

The apparatus according to claim 10 wherein said bearing elements are composed of nylon.

Claim 14

X-ray apparatus comprising: A u-shaped member including a base section mounted for rotation in a vertical plane about a horizontal axis and a pair of arm sections extending from the base section on opposite sides of said axis and generally parallel to it, a first member mounted to said base member, said first member being composed of magnetic material and having a planar surface to which said horizontal axis is perpendicular, a second member and a radiographic film changer mounted to said second member, said second member being composed of nonmagnetic material and having a planar surface in which there are recesses presented toward the planar surface on the magnetic first member, means coupling said members for relative rotation with a gap between them, a permanent magnet element in at least some of the recesses in the nonmagnetic second member, said element being movable in a direction perpendicular to the planar surface of the magnetic first member for being attracted to the planar surface of the magnetic first member to develop a frictional force that must be overcome to rotate one member and the film changer thereon relative to the other and said force being sufficient to hold said film changer in a fixed position when rotation is discontinued, said magnetic element being comprised of a polymer containing magnetized particles, said film changer being arranged to receive an x-ray image emergent from a body that is supported in a horizontal position between said arm sections.

Claim 15

X-ray apparatus comprising: A u-shaped member including a base section mounted for rotation in a vertical plane about a horizontal axis and a pair of arm sections extending from the base section on opposite sides of said axis and generally parallel to it, a first member mounted to said base member, said first member being composed of magnetic material and having a planar surface to which said horizontal axis is perpendicular, a second member and a radiographic film changer mounted to said second member, said second member being composed of nonmagnetic material and having a planar surface in which there are recesses presented toward the planar surface on the magnetic first member, means coupling said members for relative rotation with a gap between them, a permanent magnet element in at least some of the recesses in the nonmagnetic second member, said element being movable in a direction perpendicular to the planar surface of the magnetic first member for being attracted to the planar surface of the magnetic first member to develop a frictional force that must be overcome to rotate one member and the film changer thereon relative to the other and said force being sufficient to hold said film changer in a fixed position when rotation is discontinued, said magnetic element being comprised of a polymer containing magnetized particles, said film changer being arranged to receive an x-ray image emergent from a body that is supported in a horizontal position between said arm sections.