Power operated rotary excision tool

1. A power operated dermatome comprising:

a blade housing having a skin deflector to prevent excised skin from tearing as it is removed from the dermatome;

an annular rotary knife blade supported for rotation about an axis of rotation by the blade housing, the annular rotary knife blade having an inner region and comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper end of the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade portion forming a cutting edge of the annular rotary knife blade, the inner wall and the outer wall of the lower blade portion converging in a direction proceeding toward the cutting edge;

wherein the inner wall of the lower blade portion and the inner wall of the upper body portion are radially spaced apart, and at the upper end of the lower blade portion, are connected by a shoulder surface that extends transversely to the axis of rotation of the annular rotary knife blade.

2. A rotary knife blade assembly rotatable about a central axis of rotation in a power operated dermatome, the rotary knife blade assembly comprising:

a rotary knife blade comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper end of the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade portion forming a cutting edge of the rotary knife blade, the inner wall and the outer wall of the lower blade portion converging in a direction proceeding toward the cutting edge;

wherein the inner wall of the lower blade portion and the inner wall of the upper body portion are radially spaced apart and connected by a shoulder surface that extends transversely to the central axis of rotation of the rotary knife blade, the inner wall of the lower blade portion being substantially planar between the cutting edge and the shoulder surface; and

a continuous rolling bearing structure in contact with the bearing race of the outer wall of the upper body portion of the rotary knife blade, the continuous rolling bearing structure forming a convex outer surface of the rotary knife blade assembly and projecting radially outwardly from the outer wall of the upper body portion of the rotary knife blade.

3. The rotary knife blade assembly of claim 2 wherein the inner and outer walls of the lower blade portion of the rotary knife blade are frustoconical.

4. The rotary knife blade assembly of claim 2 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade extends orthogonally to the central axis of rotation of the rotary knife blade.

5. The rotary knife blade assembly of claim 2 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade is substantially planar.

6. A rotary knife blade assembly rotatable about a central axis of rotation in a power operated dermatome, the rotary knife blade assembly comprising:

a rotary knife blade comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper end of the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade portion forming a cutting edge of the rotary knife blade, the inner and outer wall converging in a direction proceeding toward the bottom surface of the lower blade portion;

wherein the inner wall of the lower blade portion and the inner wall of the upper body portion are radially spaced apart and connected by a shoulder surface that extends transversely to the central axis of rotation of the rotary knife blade, the inner wall of the lower blade portion being substantially planar between the cutting edge and the shoulder surface; and

a continuous rolling bearing structure in contact with the bearing race of the outer wall of the upper body portion of the rotary knife blade, the continuous rolling bearing structure forming a convex outer surface of the rotary knife blade assembly and projecting radially outwardly from the outer wall of the upper body portion of the rotary knife blade.

7. The rotary knife blade assembly of claim 6 wherein the inner and outer walls of the lower blade portion of the rotary knife blade are frustoconical.

8. The rotary knife blade assembly of claim 6 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade extends orthogonally to the central axis of rotation of the rotary knife blade.

9. The rotary knife blade assembly of claim 6 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade is substantially planar.

10. A rotary knife blade assembly rotatable about a central axis of rotation in a power operated dermatome, the rotary knife blade assembly comprising:

a rotary knife blade comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper end of the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade section forming a cutting edge of the rotary knife blade and defining a cutting plane of the rotary knife blade, the bottom surface of the lower blade portion extending along the cutting plane of the rotary knife blade;

wherein the inner wall of the lower blade portion and the inner wall of the upper body portion are radially spaced apart and connected by a shoulder surface that extends transversely to the central axis of rotation of the rotary knife blade, the inner wall of the lower blade portion being substantially planar between the cutting edge and the shoulder surface; and

a continuous rolling bearing structure in contact with the bearing race of the outer wall of the upper body portion of the rotary knife blade, the continuous rolling bearing structure forming a convex outer surface of the rotary knife blade assembly and projecting radially outwardly from the outer wall of the upper body portion of the rotary knife blade.

11. The rotary knife blade assembly of claim 10 wherein the inner wall and the outer wall of the lower blade portion converge in a direction proceeding toward the bottom surface of the lower blade portion.

12. The rotary knife blade assembly of claim 10 wherein the inner and outer walls of the lower blade portion of the rotary knife blade are frustoconical.

13. The rotary knife blade assembly of claim 10 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade extends orthogonally to the central axis of rotation of the rotary knife blade.

14. The rotary knife blade assembly of claim 10 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade is substantially planar.

15. A rotary knife blade rotatable about a central axis of rotation in a power operated dermatome, the rotary knife blade comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper end of the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade portion forming a cutting edge of the rotary knife blade, the inner wall and the outer wall of the lower blade portion converging in a direction proceeding toward the cutting edge;

wherein the inner wall of the lower blade portion and the inner wall of the upper body portion are radially spaced apart and connected by a shoulder surface that extends transversely to the central axis of rotation of the rotary knife blade, the inner wall of the lower blade portion being substantially planar between the cutting edge and the shoulder surface.

16. The rotary knife blade of claim 15 wherein the inner and outer walls of the lower blade portion of the rotary knife blade are frustoconical.

17. The rotary knife blade of claim 15 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade extends orthogonally to the central axis of rotation of the rotary knife blade.

18. The rotary knife blade of claim 15 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade is substantially planar.

19. A rotary knife blade rotatable about a central axis of rotation in a power operated dermatome, the rotary knife blade comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper end of the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade portion forming a cutting edge of the rotary knife blade, the inner and outer walls of the lower blade portion converging in a direction proceeding toward the bottom surface of the lower blade portion;

wherein the inner wall of the lower blade portion and the inner wall of the upper body portion are radially spaced apart and connected by a shoulder surface that extends transversely to the central axis of rotation of the rotary knife blade, the inner wall of the lower blade portion being substantially planar between the cutting edge and the shoulder surface.

20. The rotary knife blade of claim 19 wherein the inner and outer walls of the lower blade portion of the rotary knife blade are frustoconical.

21. The rotary knife blade of claim 19 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade extends orthogonally to the central axis of rotation of the rotary knife blade.

22. The rotary knife blade of claim 19 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade is substantially planar.

23. A rotary knife blade rotatable about a central axis of rotation in a power operated dermatome, the rotary knife blade comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper end of the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade section forming a cutting edge of the rotary knife blade and defining a cutting plane of the rotary knife blade, the bottom surface of the lower blade portion extending along the cutting plane of the rotary knife blade;

wherein the inner wall of the lower blade portion and the inner wall of the upper body portion are radially spaced apart and connected by a shoulder surface that extends transversely to the central axis of rotation of the rotary knife blade, the inner wall of the lower blade portion being substantially planar between the cutting edge and the shoulder surface.

24. The rotary knife blade of claim 23 wherein the inner wall and outer wall of the lower blade portion converge in a direction proceeding toward the bottom surface of the lower blade portion.

25. The rotary knife blade of claim 23 wherein the inner and outer walls of the lower blade portion of the rotary knife blade are frustoconical.

26. The rotary knife blade of claim 23 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade extends orthogonally to the central axis of rotation of the rotary knife blade.

27. The rotary knife blade of claim 23 wherein the shoulder surface that connects the inner wall of the lower blade portion and the inner wall of the upper body portion of the rotary knife blade is substantially planar.

28. A rotary knife blade assembly rotatable about a central axis of rotation in a power operated dermatome, the rotary knife blade assembly comprising:

a rotary knife blade comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade portion forming a cutting edge of the rotary knife blade, the inner and outer walls converging in a direction proceeding toward the bottom surface of the lower blade portion;

wherein the inner walls of the lower blade portion and the inner wall of the upper body portion are radially spaced apart and connected by a shoulder surface extending transversely to the central axis of rotation of the rotary knife blade and at least a portion of the inner wall of the upper body portion extending substantially parallel to the central axis of rotation of the rotary knife blade; and

a continuous rolling bearing structure in contact with the bearing race of the outer wall of the upper body portion of the upper body portion of the rotary knife blade, the continuous rolling bearing structure forming a convex outer surface of the rotary knife blade assembly and projecting radially outwardly from the outer wall of the upper body portion of the rotary knife blade.

29. A rotary knife blade rotatable about a central axis of rotation in a power operated dermatome, the rotary knife blade comprising:

an upper body portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, the outer wall of the upper body portion including a bearing race extending radially inwardly into the outer wall, the upper body portion including a driven gear; and

a lower blade portion extending from the upper body portion, the lower blade portion including an inner wall and a radially spaced apart outer wall and an upper end and an axially spaced apart lower end, a bottom surface of the lower blade portion extending along the lower end of the lower blade portion, an intersection of the bottom surface and the inner wall of the lower blade portion forming a cutting edge of the rotary knife blade, the inner and outer walls converging in a direction proceeding toward the bottom surface of the lower blade portion;

wherein the inner wall of the lower blade portion and the inner wall of the upper body portion are radially spaced apart and are connected by a shoulder surface extending transversely to the central axis of rotation of the rotary knife blade and at least a portion of the inner wall of the upper body portion extending substantially parallel to the central axis of rotation of the rotary knife blade.