1. A swing lock mechanism for a crane having an upper works, a lower works, and a swing bearing connecting the upper works and the lower works so as to allow the upper works to be rotatable with respect to the lower works, the lower works further comprising a gear with teeth thereon for use in causing rotation of the upper works; the swing lock mechanism comprising: aj a swing lock segment comprising teeth adapted to intermesh with said gear teeth when the swing lock segment is in an engaged position, b) a piston actuatably mounted in a cylinder, the cylinder being secured to the upper works and the piston being connected to said swing lock segment so as to move said swing lock segment into and out of said engagement position upon actuation of the piston and cylinder, and c) a connector link connected to said swing lock segment, said connector link having a means for rigidly holding said swing lock segment is in its engaged position to thereby prevent the swing lock segment from disengagement when resisting a swing torque.

2. The swing lock mechanism of claim 1 further comprising at least one spring normally biased to force said swing lock segment into its engaged position.

3. The swing lock mechanism of claim 2 further comprising a latch to hold said swing lock segment in a disengaged position against the bias of said spring until said latch is forced out of its latching position during reengagement of said swing lock segment.

4. The swing lock mechanism of claim 1 further comprising a slotted connection between the piston and

the swing lock segment such that the piston can be in a fully extended position even if the teeth on the swing lock segment are not meshed with the gear teeth.

5. The swing lock mechanism of claim 1 further comprising two side plates extending downwardly on opposite sides of the swing lock segment and secured to said upper works such that the side plates prevent the upper works from rotating when said swing lock segment is in its engaged position.

6. The swing lock mechanism of claim 1 wherein the piston and cylinder comprise either an air cylinder or a hydraulic cylinder.

7. The swing lock mechanism of claim 1 wherein the rigid holding means comprises a foot attached to said connector adapted to fit in a hole in a rigid portion of the swing lock mechanism.

8. A crane having an assembly for allowing quick separation of crane upper works from crane lower works comprising: a) an adapter plate secured to the upper works by link members extending from the adapter plate to the body of the upper works; b) one or more horizontal-load bearing pins extending through apertures in the base of the upper works and the adapter plate; c) a swing bearing first race bolted to the bottom of the adapter plate; d) a swing bearing second race, with drive teeth integrally formed thereon, bolted to the lower works; and e) a swing lock mechanism actuatable into and out of a position wherein the mechanism engages the

drive teeth of the second race to prevent rotation between the upper works and the lower works.

9. The crane of claim 8 wherein the swing lock mechanism comprises a swing lock segment having teeth adapted to intermesh with the drive teeth when the swing lock segment is in an engaged position.

10. The crane of claim 9 wherein the swing lock mechanism further comprising a piston in a cylinder for withdrawing and engaging said swing lock segment.

11. The crane of claim 9 wherein the swing lock mechanism further comprises at least one spring normally biased to force said swing lock segment into its engaged position.

12. The crane of claim 9 wherein the swing lock mechanism further comprises a connector link connected to said swing lock segment, said connector link having a foot extending from one end thereof adapted to 'fit into a hole when said swing lock segment is in its engaged position to thereby prevent the swing lock segment from disengagement when resisting a swing torque.

13. The crane of claim 12 wherein the swing lock mechanism further comprises a latch to hold said swing lock segment in a disengaged position against the bias of said spring until said latch is forced out of its latching position during reengagement of said swing lock segment.

14. The crane of claim 12 wherein the swing lock mechanism further comprises a slotted connection between the piston and the swing lock segment such that the piston can be in a fully extended position even if

the teeth on the swing lock segment are not meshed with the drive teeth.

15. The crane of claim 8 wherein the swing lock mechanism comprises: a) a swing lock segment comprising teeth adapted to intermesh with said teeth of said second race when the swing lock segment is in an engaged position, b) a piston actuatably mounted in a cylinder, the cylinder being secured to the upper works and the piston being connected to said swing lock segment so as to move said swing lock segment into and out of said engagement position upon actuation of the piston and cylinder, and c) a connector link connected to said swing lock segment, said connector link having a foot extending from one end thereof adapted to fit into a hole in a rigid portion of said swing lock mechanism when said swing lock segment is in its engaged position to thereby provide a rigid contact between the teeth of the swing lock segment and said gear teeth.

16. The crane of claim 8 wherein the adapter plate is generally rectangular and comprises four tangs, one of each extending from each corner of the adapter plate.

17. The crane of claim 16 wherein the links each comprise two strap members spaced so that the tangs fit between the straps and rest on a bolt extending through a block welded between the ends of the straps extending below the tangs.

18. The crane of claim 8 wherein the link members are pinned to the body of the upper works.

19. The crane of claim 8 further comprising reinforcing ribs extending vertically downward from the bottom of the adapter plate, including a circular rib concentric with said swing bearing first race.

20. The crane of claim 8 further comprising shear blocks wherein said one or more horizontal-load bearing pins and shear blocks are adapted for transferring horizontal and torque loads between said upper works and said adapter plate.

21. The crane of claim 8 wherein the adapter plate comprises a plate member with apertures therethrough such that power generating means on the upper works can effectuate rotation of the upper work relative to the lower works.