Actuation of a device comprising mechanical arms
Some embodiments of the invention relate to a mechanism for actuating a shaft having two degrees of freedom, comprising: a first actuator configured to rotate the shaft around the shaft axis, and a second actuator configured to bend the shaft using one or more elongated elements attached to the shaft, wherein actuation of the first actuator indirectly manipulates the elongated elements controlled by the second actuator, thereby affecting operation of the second actuator. Some embodiments relate to motorized actuation of a system comprising at least one surgical arm.
1. An actuating mechanism comprising:
a first gear operably coupled to a threaded screw, said first gear configured to rotate said screw around its screw axis;
first and second rider elements coupled to threading of said threaded screw, wherein said first rider element is attached to a first elongated element and said second rider element is attached to a second elongated element;
a shaft having a long axis, said screw axis of said screw and said long axis of said shaft being colinear with each other;
a second gear configured to rotate said shaft around said long axis of said shaft; and
a housing in which the threaded screw is received, the housing being disposed around said long axis of said shaft, the housing having therein designated elongated grooves within which each of the first and second elements are positioned, said elongated grooves being configured such that actuation of the second gear does not twist the elongated elements about the long axis of said shaft;
wherein rotation of said threaded screw moves said rider elements in opposing directions along said long axis of said shaft, tensioning said first elongated element and releasing tension of said second elongated element or vice versa.
2. The mechanism according to claim 1 , wherein rotational movement of said rider elements around the screw is limited by one or more protrusions configured on an internal face of the housing.
3. The mechanism according to claim 2 , wherein (i) each of said first and second elongated elements is respectively and proximally attached at to said respective rider element, and (ii) each of said elongated elements is respectively and distally attached to said shaft at a location distal to a flexible joint of said shaft.
4. The mechanism of claim 3 wherein said second gear is located distal to said first gear.
5. The mechanism of claim 4 wherein both of said first and second riders are located distal to the first gear and proximal to the second gear.
6. The mechanism according to claim 1 , wherein (i) each of said first and second elongated elements is respectively and proximally attached to its respective rider element, and (ii) each of said elongated elements is respectively and distally attached to said shaft at a location distal to a flexible joint of said shaft.
7. The mechanism of claim 6 wherein said second gear is located distal to said first gear.
8. The mechanism of claim 7 wherein both of said first and second riders are located distal to the first gear and proximal to the second gear.
9. The mechanism of claim 1 wherein said first and second riders are both disposed in a location, along the shaft axis, that is in between the first and second gears.