Patient support having auto contour

1. A patient support apparatus comprising

a frame,

at least one drop rail coupled to the frame and tiltable relative to the frame,

a seat section supported by the at least one drop rail to tilt therewith,

a thigh section situated, at least in part, above the at least one drop rail, and

a head section coupled to the frame and coupled to the at least one drop rail, the head section being raiseable and lowerable to tilt the at least one drop rail relative to the frame, wherein the seat section is mounted on the at least one drop rail for translation along the at least one drop rail as the head section is raised and lowered and further comprising a link coupled to the frame and coupled to the seat section to move the seat section along the drop rail as the at least one drop rail tilts during raising and lowering of the head section, wherein the head section is coupled to the frame for pivoting movement about a first axis, the at least one drop rail is coupled to the frame for pivoting movement about a second axis, and the thigh section is coupled to the seat section for pivoting movement about a third axis located between the first and second axes.

2. The apparatus of claim 1 , wherein the head section is coupled to the at least one drop rail so that the weight of a patient supported on the seat section exerts a force on the head section in a direction urging the head section to raise.

3. The apparatus of claim 1 , wherein the at least one drop rail has a longitudinally extending slot in which a pin coupled to the head section is received, a roller is mounted on the pin for rotation, and the roller rolls on the at least one drop rail as the head section is raised and lowered.

4. The apparatus of claim 3 , wherein the pin and the roller move toward a head end of the slot when the head section is raised and the pin and the roller move toward a foot end of the slot when the head section is lowered.

5. The apparatus of claim 1 , further comprising a linkage coupled to the head section and coupled to the thigh section, the linkage having a first mode of operation in which the seat and thigh sections remain substantially parallel as the at least one drop rail tilts, and the linkage having a second mode of operation in which the thigh section tilts relative to the seat section as the at least one drop rail tilts.

6. A patient support apparatus comprising

a frame,

at least one drop rail coupled to the frame and tiltable relative to the frame,

a seat section supported by the at least one drop rail to tilt therewith,

a thigh section situated, at least in part, above the at least one drop rail,

a head section coupled to the frame and coupled to the at least one drop rail, the head section being raiseable and lowerable to tilt the at least one drop rail relative to the frame, wherein the seat section is mounted on the at least one drop rail for translation along the at least one drop rail as the head section is raised and lowered and further comprising a link coupled to the frame and coupled to the seat section to move the seat section along the drop rail as the at least one drop rail tilts during raising and lowering of the head section, and

a linkage coupled to the head section and coupled to the thigh section, the linkage having a first mode of operation in which the seat and thigh sections remain substantially parallel as the at least one drop rail tilts, and the linkage having a second mode of operation in which the thigh section tilts relative to the seat section as the at least one drop rail tilts, wherein the head section is movable between a lowered position in which the head section is generally horizontal and a raised position in which the head section extends generally upwardly relative to the frame, the head section having an intermediate position between the raised position and the lowered position, and when the linkage is in the second mode of operation a cam acts on the thigh section as the thigh section moves relative to at least one drop rail from a first position generally parallel to the at least one drop rail to a second position wherein the thigh section is raised upwardly relative to the drop rail.

7. The apparatus of claim 1 , wherein the link is pivotably coupled to the seat section and pivotably coupled to the frame.

8. A patient support apparatus comprising

a frame,

at least one drop rail coupled to the frame and tiltable relative to the frame,

a seat section supported by the at least one drop rail to tilt therewith,

a thigh section situated, at least in part, above the at least one drop rail, and

a head section coupled to the frame and coupled to the at least one drop rail, the head section being raiseable and lowerable to tilt the at least one drop rail relative to the frame, wherein the seat section is mounted on the at least one drop rail for translation along the at least one drop rail as the head section is raised and lowered and further comprising a link coupled to the frame and coupled to the seat section to move the seat section along the drop rail as the at least one drop rail tilts during raising and lowering of the head section, wherein the at least one drop rail comprises a pair of laterally spaced drop rails, each drop rail has a foot end portion pivotably coupled to the frame, the pair of laterally spaced drop rails tilt downwardly from a first position generally parallel to the frame to a lowered second position as the head section is raised, and each drop rail has a head end portion that is lower in elevation than the foot end portion when the drop rail is in the lowered second position.

9. A patient support apparatus comprising

a frame,

at least one drop rail coupled to the frame and tiltable relative to the frame,

a seat section supported by the at least one drop rail to tilt therewith,

a thigh section situated, at least in part, above the at least one drop rail,

a head section coupled to the frame and coupled to the at least one drop rail, the head section being raiseable and lowerable to tilt the at least one drop rail relative to the frame, wherein the seat section is mounted on the at least one drop rail for translation along the at least one drop rail as the head section is raised and lowered and further comprising a link coupled to the frame and coupled to the seat section to move the seat section along the drop rail as the at least one drop rail tilts during raising and lowering of the head section, and

a linkage having a cam supported by the frame, the linkage also including a roller assembly interposed between the thigh section and the cam, and cam moving beneath the roller assembly to move the roller assembly thereby to tilt the thigh section relative to the at least one drop rail.

10. The apparatus of claim 9 , wherein the cam has a first portion that moves beneath the roller assembly to raise the thigh section as the head section moves upwardly from a lowered position generally parallel to the frame to an intermediate position, and the cam has a second portion that moves beneath the roller assembly to lower the thigh section as the head section moves further upwardly from the intermediate position to a raised position.

11. The apparatus of claim 9 , wherein the roller assembly is coupled to the frame for movement in a generally vertical direction, the roller assembly includes a top roller positioned to contact the thigh section, and the roller assembly includes a bottom roller positioned to contact the cam.

12. The apparatus of claim 9 , wherein the linkage comprises a lockable device coupling the cam to the head section, the lockable device being unlocked when the linkage is in a first mode of operation so that the cam remains generally stationary beneath the roller assembly as the head section is raised and lowered, and the lockable device being locked when the linkage is in a second mode of operation so that raising and lowering of the head section moves the cam beneath the roller assembly.

13. The apparatus of claim 12 , wherein the lockable device comprises a spring clutch including a housing coupled to the head section, a coil gripping spring received inside the housing, and a connecting rod, the connecting rod has a first portion received inside the gripping spring, the connecting rod has a second portion coupled to the cam, the spring clutch is lockable so that the gripping spring constricts around the connecting rod to couple the head section to the cam, the spring clutch is releasable so that the gripping spring loosens its grip on the connecting rod to decouple the head section from the cam.

14. The apparatus of claim 12 , further comprising at least one handle coupled to the head section and movable between a locking position and a releasing position, the lockable device being locked when the at least one handle is in the locking position, and the lockable device being unlocked when the at least one handle is in the releasing position.

15. The apparatus of claim 14 , further comprising a member and a cable extending from the member to the lockable device, the cable is pulled to unlock the lockable device when the at least one handle moves from the locking position to the releasing position.

16. The apparatus of claim 12 , wherein the at least one handle includes first and second notches corresponding to the locking and releasing positions of the handle, respectively, and further comprising a locking member coupled to the head section and a spring biasing a locking portion of the locking member into one of the two notches to prevent the handle from moving when the head section is raised, and wherein a post extending from the frame displaces the locking member to disengage the locking portion from the associated notch to free the handle for movement when the head section is moved to the lowered position.

17. The apparatus of claim 1 , wherein the thigh section is pivotably coupled to the seat section.

18. The apparatus of claim 17 , wherein the thigh section extends beyond a foot end portion of the at least one drop rail.

19. The apparatus of claim 17 , further comprising a foot section pivotably coupled to the thigh section, the foot section pivoting relative to the thigh section as the drop rail tilts during raising and lowering of the head section.