ACTUATOR
An actuator includes an outer sleeve with at least a pair of helical slots coiling in a first direction, an inner sleeve with at least a pair of helical slots coiling in a second, opposite direction, and a driver including bearings received through the helical slots of the inner sleeve and into the helical slots of the outer sleeve.
1 . An actuator comprising:
an outer sleeve with at least a pair of helical slots coiling in a first direction;
an inner sleeve with at least a pair of helical slots coiling in a second, opposite direction; and
a driver including bearing surfaces received through the helical slots of the inner sleeve and into the helical slots of the outer sleeve.
2 . The actuator of claim 1 in which the helical slots of the inner sleeve wrap at least partially around the inner sleeve.
3 . The actuator of claim 1 in which the helical slots of the outer sleeve wrap at least partially around the outer sleeve.
4 . The actuator of claim 1 in which the helical slots of the outer sleeve have a constant pitch.
5 . The actuator of claim 4 in which the helical slots of the inner sleeve have a constant pitch.
6 . The actuator of claim 5 in which the constant pitch of the helical slots of the outer sleeve is different than the constant pitch of the helical slots of the inner sleeve.
7 . The actuator of claim 1 in which the helical slots of the outer and inner sleeve have a non-constant pitch.
8 . The actuator of claim 7 in which the non-constant pitch of the helical slots of the outer sleeve is different than the non-constant pitch of the helical slots of the inner sleeve.
9 . The actuator of claim I in which there are at least four helical slots in the outer sleeve and four helical slots in the inner sleeve.
10 . The actuator of claim 1 in which in which the driver includes a cross-member supporting said bearing surfaces thereon.
11 . The actuator of claim 10 in which the driver further includes a piston extending from the cross-member.
12 . The actuator of claim 10 in which the bearing surfaces are roller bearings and there are a pair of roller bearings on each end of the cross-member, one inner roller bearing of each pair for a helical slot in the inner sleeve, one outer roller bearing of each pair for a helical slot in the outer sleeve.
13 . The actuator of claim 12 in which said bearings are journal bearings.
14 . The actuator of claim 1 in which said slots are tapered.
15 . The actuator of claim 14 in which said bearings are conical bearings.
16 . The actuator of claim 1 in which in the driver is hydraulically driven.
17 . The actuator of claim 1 in which the driver is electrically driven.
18 . The actuator of claim 1 in which the driver is mechanically driven.
19 . The actuator of claim 1 in which the driver includes at least two cross members.