Power operated rotary knife

1. A power operated rotary knife comprising:

a two-part annular rotary knife blade rotating about an axis of rotation and defining a knife blade bearing surface, the knife blade including an annular carrier portion, an annular blade portion and an attachment structure;

a blade housing including an inner wall defining a blade housing bearing surface; and

a blade-blade housing bearing structure disposed between the knife blade bearing surface and the blade housing bearing surface;

the knife blade carrier portion including a first end and an axially spaced apart second end, an outer wall and a radially inward spaced apart inner wall extending respectively between the first end and the second end, and a set of gear teeth;

the knife blade blade portion including a first end and an axially spaced apart second end, an outer wall and a radially inward spaced apart inner wall extending respectively between the first end and the second end, and a cutting edge at the blade portion second end, the blade portion configured to be received in a nested relationship by the carrier portion; and

the knife blade attachment structure for releasably securing the blade portion to the carrier portion, the attachment structure including a plurality of projections extending from one of the outer wall of the blade portion and the inner wall of the carrier portion and a plurality of sockets disposed in the other of the outer wall of the blade portion and the inner wall of the carrier portion, each of the plurality of projections being received in a respective different one of the plurality of sockets to releasably secure the blade portion to the carrier portion.

2. The power operated rotary knife of claim 1 wherein the knife blade bearing surface comprises a bearing race extending radially into the outer wall of the carrier portion.

3. The power operated rotary knife of claim 2 wherein the bearing race is axially spaced from the first end of the carrier portion.

4. The power operated rotary knife of claim 1 wherein the set of gear teeth is formed in the outer wall of the carrier portion and is axially spaced from the first end of the carrier portion.

5. The power operated rotary knife of claim 2 where in the set of gear teeth is axially spaced from the bearing race.

6. The power operated rotary knife of claim 1 wherein each of the plurality of sockets includes a projection receiving opening and a camming surface extending from the projection receiving opening, the plurality of projections and the plurality of sockets configured and positioned relative to each other such that when the blade portion is received in nested relationship by the carrier portion and the blade and carrier portions are properly rotationally aligned, each of the plurality of projections is received into a respective projection receiving opening of the plurality of sockets and, upon rotating the blade portion with respect to the carrier portion in a direction of rotation to a locked position, each of the projections of the plurality of projections moves along a path of travel within a respective socket of the plurality of sockets and is axially displaced by the camming surface of the socket such that the outer wall of the blade portion and the inner wall of the carrier portion are urged toward each other and the blade portion is secured to the carrier portion.

7. The power operated rotary knife of claim 6 wherein the direction of rotation of the blade portion with respect to the carrier portion to move to the locked position is opposite in rotational direction to a direction of rotation of the blade in a rotary knife.

8. The power operated rotary knife of claim 6 wherein a direction of rotation of the blade in a rotary knife is counterclockwise when viewed from the blade central axis axially above the first end of the carrier portion and the direction of rotation of the blade portion with respect to the carrier portion is clockwise when viewed from the blade central axis axially above the first end of the blade carrier.

9. The power operated rotary knife of claim 1 wherein the inner and outer walls of the blade portion are substantially parallel.

10. The power operated rotary knife of claim 1 wherein the inner and outer walls of the blade portion include frustoconical portions.

11. The power operated rotary knife of claim 1 wherein the inner and outer walls of the blade portion are substantially frustoconical.

12. The power operated rotary knife of claim 1 wherein the plurality of projections extend from the outer wall of the blade portion and the plurality of sockets extend into the inner wall of the carrier portion.

13. The power operated rotary knife of claim 12 wherein the plurality of projections comprise radially outwardly extending projections.

14. The power operated rotary knife of claim 12 wherein the plurality of projections comprise projections that extend outwardly from a general extent of the outer wall of the blade portion.

15. The power operated rotary knife of claim 11 wherein each the plurality of sockets comprises a recess extending radially into the inner wall of the carrier portion.

16. The power operated rotary knife of claim 15 wherein the recess of each of the plurality of sockets has a longitudinal extent that is substantially parallel to the first end of the carrier portion.

17. The power operated rotary knife of claim 11 wherein each of the plurality of sockets comprises an opening extending through the inner and outer walls of the carrier portion.

18. The power operated rotary knife of claim 17 wherein the recess of each of the plurality of sockets has a longitudinal extent that is substantially parallel to the first end of the carrier portion.

19. The power operated rotary knife of claim 1 wherein the plurality of projections extend from the inner wall of the carrier portion and the plurality of sockets extend into the outer wall of the blade portion.

20. The power operated rotary knife of claim 19 wherein the plurality of sockets comprises an opening extending through the inner and outer walls of the carrier portion.

21. The power operated rotary knife of claim 20 wherein the recess of each of the plurality of sockets has a longitudinal extent that is substantially parallel to the first end of the blade portion.

22. The power operated rotary knife of claim 1 wherein each socket of the plurality of sockets includes a first surface and a spaced apart camming surface proceeding toward the first surface and further includes a first, opening region, a second, tapering region, and a third, locking region, the first, opening region defining a projection receiving opening.

23. The power operated rotary knife of claim 1 wherein the blade portion comprises a steel stamping.

24. The power operated rotary knife of claim 1 wherein the plurality of projections includes four projections and the plurality of sockets includes four sockets.

25. The power operated rotary knife of claim 1 wherein the plurality of projections includes six projections and the plurality of sockets includes six sockets.

26. An annular rotary knife blade for rotation about an axis of rotation in a power operated rotary knife, the rotary knife blade comprising:

an annular carrier portion including a first end and an axially spaced apart second end, an outer wall and a radially inward spaced apart inner wall extending respectively between the first end and the second end, the carrier portion including a set of gear teeth and a knife blade bearing surface;

an annular blade portion including a first end and an axially spaced apart second end, an outer wall and a radially inward spaced apart inner wall extending respectively between the first end and the second end, and a cutting edge at the blade portion second end, the blade portion configured to be received in a nested relationship by the carrier portion; and

an attachment structure for releasably securing the blade portion to the carrier portion, the attachment structure including a plurality of projections extending from one of the outer wall of the blade portion and inner wall of the carrier portion and a plurality of sockets disposed in the other of the outer wall of the blade portion and the inner wall of the carrier portion, each of the plurality of projections being received in a respective different one of the plurality of sockets to releasably secure the blade portion to the carrier portion.

27. The annular rotary knife blade of claim 26 wherein the knife blade bearing surface comprises a bearing race extending radially into the outer wall of the carrier portion.

28. The annular rotary knife blade of claim 27 wherein the bearing race is axially spaced from the first end of the carrier portion.

29. The annular rotary knife blade of claim 26 wherein the set of gear teeth is formed in the outer wall of the carrier portion and is axially spaced from the first end of the carrier portion.

30. The annular rotary knife blade of claim 27 where in the set of gear teeth is axially spaced from the bearing race.

31. The annular rotary knife blade of claim 26 wherein the inner and outer walls of the blade portion are substantially parallel.

32. The annular rotary knife blade of claim 26 wherein the plurality of projections extend from the outer wall of the blade portion and the plurality of sockets extend into the inner wall of the carrier portion.

33. The annular rotary knife blade of claim 32 wherein the plurality of projections comprise radially outwardly extending projections.

34. The annular rotary knife blade of claim 32 wherein the plurality of projections comprise projections that extend outwardly from a general extent of the outer wall of the blade portion.

35. The annular rotary knife blade of claim 32 wherein each the plurality of sockets comprises a recess extending radially into the inner wall of the carrier portion.

36. The annular rotary knife blade of claim 35 wherein the recess of each of the plurality of sockets has a longitudinal extent that is substantially parallel to the first end of the carrier portion.

37. The annular rotary knife blade of claim 26 wherein each of the plurality of sockets comprises an opening extending through the inner and outer walls of the carrier portion.

38. The annular rotary knife blade of claim 37 wherein the recess of each of the plurality of sockets has a longitudinal extent that is substantially parallel to the first end of the carrier portion.

39. The annular rotary knife blade of claim 26 wherein the plurality of projections extend from the inner wall of the carrier portion and the plurality of sockets extend into the outer wall of the blade portion.

40. The annular rotary knife blade of claim 39 wherein the plurality of sockets comprises an opening extending through the inner and outer walls of the carrier portion.

41. The annular rotary knife blade of claim 40 wherein the recess of each of the plurality of sockets has a longitudinal extent that is substantially parallel to the first end of the blade portion.

42. The annular rotary knife blade of claim 26 wherein each of the plurality of sockets includes a projection receiving opening and a camming surface extending from the projection receiving opening, the plurality of projections and the plurality of sockets configured and positioned relative to each other such that when the blade portion is received in nested relationship by the carrier portion and the blade and carrier portions are properly rotationally aligned, each of the plurality of projections is received into a respective projection receiving opening of the plurality of sockets and, upon rotating the blade portion with respect to the carrier portion in a direction of rotation to a locked position, each of the projections of the plurality of projections moves along a path of travel within a respective socket of the plurality of sockets and is axially displaced by the camming surface of the socket such that the outer wall of the blade portion and the inner wall of the carrier portion are urged toward each other and the blade portion is secured to the carrier portion.

43. The annular rotary knife blade of claim 42 wherein the direction of rotation of the blade portion with respect to the carrier portion to move to the locked position is opposite in rotational direction to a direction of rotation of the blade in a rotary knife.

44. The annular rotary knife blade of claim 42 wherein a direction of rotation of the blade in a rotary knife is counterclockwise when viewed from the blade central axis axially above the first end of the blade carrier and a direction of rotation of the blade portion with respect to the carrier portion is clockwise when viewed from the blade central axis axially above the first end of the blade carrier.

45. The annular rotary knife blade of claim 26 wherein the inner and outer walls of the blade portion include substantially frustoconical portions.

46. The annular rotary knife blade of claim 26 wherein the inner and outer walls of the blade portion are substantially frustoconical.

47. The annular rotary knife blade of claim 26 wherein each socket of the plurality of sockets includes a first surface and a spaced apart camming surface proceeding toward the first surface and further includes a first, opening region, a second, tapering region, and a third, locking region, the first, opening region defining a projection receiving opening.

48. The annular rotary knife blade of claim 26 wherein the blade portion comprises a steel stamping.

49. The annular rotary knife blade of claim 26 wherein the plurality of projections includes four projections and the plurality of sockets includes four sockets.

50. The annular rotary knife blade of claim 26 wherein the plurality of projections includes six projections and the plurality of sockets includes six sockets.