Device for centering an x-ray film cassette

Claim 2

Apparatus for centering an X-ray cassette with respect to a central point on a support table thereof, comprising first and second rings mounted on said table for rotation about said point, two four-bar parallelogram linkages, each comprising one pair of parallel rods having near and remote ends, a clamp member pivotally secured to said remote ends, and the near ends pivotally secured to said support table, the two linkages positioned such that said clamp members are mutually parallel and on opposite sides of said point, a drive link connecting each linkage to said first ring, a pair of 2-bar linkages, such comprising a first arm having a first end pivotally secured to said table and a far end, and a second arm having a first end pivotally secured to said second ring and a far end, said far ends pivotally secured together in a junction, said 2-bar linkages positioned such that the two junctions are on opposite sides of said point and define a line between them generally parallel to and midway of said parallel clamping members, an actuating lever pivotally mounted to said apparatus, and resilient means connecting said lever to said rings whereby movement of said lever in one direction resiliently urges said rings to rotate in a corresponding direction, and thereby move said clamping members and junctions symmetrically toward said point, and vice versus.

Claim 3

Apparatus according to claim 1 further comprising a hub on said table formeD as a round cylindrical post, with said rings situated rotatably about said hub.

Claim 4

Apparatus according to claim 1 further comprising means for locking said lever in a selected position.

Claim 5

Apparatus according to claim 1 wherein said clamp members and junctions respectively have a distance apart corresponding to the degrees of rotation of said rings, the apparatus further comprising at least one switch on said table and at least one switch actuator rotatable with said rings, drive means for displacing said table laterally, whereby sufficient rotation of said rings for said switch actuator to contact and activate said switch, and thereby activate said drive means for displacing said table.

Claim 6

Apparatus for centering an X-ray film cassette with respect to a central point on a support table thereof, comprising a first member mounted on said table for rotation about a point on said table, a second member mounted similarly as the first member for rotation about the same point, a pair of linkages each defining a parallelogram of four links consisting of a first link fixed relative to said table, a second link being a clamping member spaced from the first link, and two parallel links pivotally connecting the first and second links, these linkages positioned such that said clamping members are parallel, spaced spart about said point, and movable symmetrically toward and away each other, first means connecting said first member and said two linkages, whereby rotation of the first means causes said movement of said clamping members, a pair of secondary linkages, each comprising a first bar having one end pivotally secured to said table and a far end, and a second bar having one end pivotally secured to said second member and a far end, with said far ends pivotally secured together at a junction, said junctions being spaced apart symmetrically about said point and movable toward and away from each other, a lever pivotally mounted to said apparatus, and resilient means interconnecting said lever and said first and second members, whereby movement of the lever in one direction resiliently urges said members to rotate about said point in a corresponding direction, and thereby causes said clamping members and junctions to move symmetrically as defined.

Claim 7

Apparatus for centering an X-ray film cassette with respect to a central point on a support table thereof, comprising a first member mounted on said table for rotation about a point on said table, a second member mounted similarly as the first member for rotation about the same point, a pair of linkages each defining a parallelogram of four links consisting of a first link fixed relative to said table, a second link being a clamping member spaced from the first link, and two parallel links pivotally connecting the first and second links, these linkages positioned such that said clamping members are parallel, spaced spart about said point, and movable symmetrically toward and away each other, first means connecting said first member and said two linkages, whereby rotation of the first means causes said movement of said clamping members, a pair of secondary linkages, each comprising a first bar having one end pivotally secured to said table and a far end, and a second bar having one end pivotally secured to said second member and a far end, with said far ends pivotally secured together at a junction, said junctions being spaced apart symmetrically about said point and movable toward and away from each other, a lever pivotally mounted to said apparatus, and resilient means interconnecting said lever and said first and second members, whereby movement of the lever in one direction resiliently urges said members to rotate about said point in a corresponding direction, and thereby causes said clamping members and junctions to move symmetrically as defined.