Braiding machine and methods of use

1. A braiding system, comprising:

a plurality of elongate members each having an upper portion and a lower portion, wherein individual elongate members are configured to receive individual filaments;

an upper drive unit configured to act against the upper portions of the elongate members; and

a lower drive unit configured to act against the lower portions of the elongate members,

wherein the upper and lower drive units are configured to act against the upper and lower portions of the elongate members in synchronization, and wherein the upper and lower drive units are configured to act against the upper and lower portions of the elongate members to (i) drive the elongate members radially inward, (ii) drive the elongate members radially outward, and (iii) move the elongate members along an arcuate path with respect to a longitudinal axis coaxial with the upper and lower drive units.

2. The braiding system of claim 1 wherein the upper drive unit constrains the upper portions of the elongate members, and wherein the lower drive unit constrains the lower portions of the elongate members.

3. The braiding system of claim 1 wherein the upper and lower drive units are substantially identical.

4. The braiding system of claim 1 wherein the upper and lower drive units are mechanically synchronized to move together.

5. A braiding system, comprising:

a plurality of elongate members each having an upper portion and a lower portion, wherein individual elongate members are configured to receive individual filaments;

an upper drive unit configured to act against the upper portions of the elongate members, wherein the upper drive unit includes (a) an outer assembly having outer slots and (b) an inner assembly having inner slots; and

a lower drive unit configured to act against the lower portions of the elongate members, wherein the lower drive unit includes (a) an outer assembly having outer slots and (b) an inner assembly having inner slots,

wherein the upper and lower drive units are configured to act against the upper and lower portions of the elongate members in synchronization, and wherein individual ones of the elongate members are constrained within individual ones of the inner and/or outer slots.

6. The braiding system of claim 5 wherein the number of outer slots of the upper and lower drive units is twice as great as the number of inner slots of the upper and lower drive units.

7. The braiding system of claim 5 , further comprising:

at least one outer drive mechanism configured to drive at least a portion of the elongate members from the outer slots to the inner slots; and

at least one inner drive mechanism configured to drive the portion of the elongate members from the inner slots to the outer slots.

8. The braiding system of claim 1 wherein the upper portions of the elongate members are proximate to an upper end of the elongate members, and wherein the lower portions of the elongate members are proximate to a lower end of the elongate members.

9. A braiding system, comprising:

a drive unit including—

an outer assembly including at least one outer cam and outer slots;

an inner assembly coaxially aligned with the outer assembly, the inner assembly including an inner cam and inner slots;

a plurality of elongate members, wherein individual elongate members are constrained within individual inner and/or outer slots;

an outer drive mechanism configured to rotate the at least one outer cam to drive at least a subset of the elongate members from the outer slots to the inner slots; and

an inner drive mechanism configured to rotate the inner cam to drive the subset of the elongate members from the inner slots to the outer slots.

10. The braiding system of claim 9 further comprising a drive system for rotating the inner assembly relative to the outer assembly.

11. The braiding system of claim 9 wherein the inner and outer assemblies are substantially coplanar.

12. The braiding system of claim 9 wherein the number of outer slots is different than the number of inner slots.

13. The braiding system of claim 9 wherein—

the outer assembly further includes (a) a first outer cam, (b) a second outer cam, and (c) outer drive members radially aligned with the outer slots, wherein rotation of the first outer cam drives a first set of the outer drive members radially inward, and wherein rotation of the second outer cam drives a second set of the outer drive members radially inward; and

the inner assembly further includes inner drive members radially aligned with the inner slots, wherein rotation of the inner cam drives the inner drive members radially outward.

14. The braiding system of claim 13 wherein the first and second outer cams each include a radially-inward facing surface with a first periodic shape, and wherein the inner cam has a radially-outward facing surface with a second periodic shape.

15. The braiding system of claim 14 wherein the first and second periodic shapes are different.

16. A method of forming a tubular braid, comprising:

driving upper end portions of a first set of elongate members of a plurality of elongate members radially inward, while synchronously driving lower end portions of the first set of elongate members radially inward;

rotating the first set of elongate members in a first direction; and

driving the upper end portions of the first set of elongate members radially outward, while synchronously driving the lower end portions of the first set of elongate members radially outward.

17. The method of claim 16 , further comprising:

driving upper end portions of a second set of elongate members of the plurality of elongate members radially inward, while synchronously driving lower end portions of the second set of elongate members radially inward;

rotating the second set of elongate members in a second direction; and

driving the upper end portions of the second set of elongate members radially outward, while synchronously driving the lower end portions of the second set of elongate members radially outward.

18. The method of claim 16 , further comprising:

positioning individual filaments in corresponding ones of the elongate members; and securing the filaments to a mandrel.

19. The method of claim 16 , wherein driving the first set of elongate members radially inward includes driving the elongate members radially inward toward a central axis, and wherein the method further comprises constraining the elongate members such that the elongate members do not move in a direction parallel to the central axis.