Extension joint for a marine drive
An extension joint device for a marine drive comprises a first cylinder and a second cylinder which is telescopically extendable and retractable relative to the first cylinder to adjust a length of the extension joint. Together, the first and second cylinders define a sealed cylindrical cavity which is extended and retracted upon extension and retraction of the second cylinder relative to the first cylinder, respectively. an electrical connector extends through the extension joint, the electrical connector having a helical shape in the sealed cylindrical cavity which is extended and compressed upon extension and retraction of the second cylinder relative to the first cylinder. A slip ring, through which the electrical connector extends, is configured to permit rotation of a first portion of the electrical connector relative to a second portion of the electrical connector, thereby facilitating compression and extension of the helical shape.
1 . An extension joint device for a marine drive, the extension joint device comprising:
a first cylinder;
a second cylinder that is telescopically extendable and retractable relative to the first cylinder to adjust a length of the extension joint device;
wherein together the first and second cylinders define a sealed cylindrical cavity which is extended and retracted upon extension and retraction of the second cylinder relative to the first cylinder, respectively;
an electrical connector extending through the extension joint device, the electrical connector having a helical shape in the sealed cylindrical cavity which is extended and compressed upon extension and retraction of the second cylinder relative to the first cylinder; and
a slip ring through which the electrical connector extends, wherein the slip ring is configured to permit rotation of a first portion of the electrical connector relative to a second portion of the electrical connector, thereby facilitating compression and extension of the helical shape.
2 . The extension joint device according to claim 1 , wherein the slip ring is disposed on one end of the sealed cylindrical cavity.
3 . The extension joint device according to claim 1 , wherein the slip ring comprises a stationary part and a rotatable part which is rotatable relative to the stationary part.
4 . The extension joint device according to claim 3 , wherein the rotatable part is disposed in the sealed cylindrical cavity.
5 . The extension joint device according to claim 3 , wherein the slip ring comprises an annular contactor and a point contactor which remains coupled to the annular contactor as the rotatable part is rotated relative to the stationary part.
6 . The extension joint device according to claim 1 , wherein the electrical connector comprises a first connector cable and a second connector cable which are intertwined to form a double helical shape.
7 . The extension joint device according to claim 6 , further comprising sliding seals between the first cylinder and the second cylinder.
8 . The extension joint device according to claim 1 , further comprising an actuator configured to move the second cylinder relative to the first cylinder.
9 . The extension joint device according to claim 8 , wherein the actuator comprises a hydraulic pump which pumps a hydraulic fluid into an annulus between the first and second cylinders so as to move the second cylinder relative to the first cylinder.
10 . The extension joint device according to claim 1 , further comprising a locking mechanism movable into and between an unlocked position in which the second cylinder is extendable and retractable relative to the first cylinder and a locked position in which the second cylinder is fixed relative to the first cylinder.
11 . The extension joint device according to claim 10 , wherein the locking mechanism is configured to selectively secure the second cylinder in one of a plurality of positions relative to the first cylinder.
12 . The extension joint device according to claim 1 , wherein the electrical connector comprises an over-molded wire, and further comprising a protective sheath containing the electrical connector, wherein the protective sheath reduces frictional abrasion of the electrical connector during movement of the second cylinder relative to the first cylinder.
13 . The extension joint device according to claim 12 , wherein the electrical connector comprises a first connector cable and second connector cable which are intertwined, and wherein the protective sheath includes a first helical sleeve and a second helical sleeve on the first and second connector cables, respectively, wherein the first and second connector cables and first and second protective sheaths forming a double helical shape.
14 . The extension joint device according to claim 12 , wherein the protective sheath has a helical shape and contains the helical shape of the electrical connector.
15 . The extension joint device according to claim 14 , wherein the helical shapes of the protective sheath and the electrical connector are extended and compressed upon extension and retraction, respectively, of the second cylinder relative to the first cylinder.
16 . The extension joint device according to claim 13 , wherein the protective sheath is made of an abrasion resistant material that is elastically deformable.
17 . The extension joint device according to claim 1 , further comprising a protective sheath, the protective sheath having a helical shape and containing the helical shape of the electrical connector.
18 . The extension joint device according to claim 17 , wherein the helical shapes of the protective sheath and the electrical connector are extended and compressed upon extension and retraction, respectively, of the second cylinder relative to the first cylinder.
19 . The extension joint device according to claim 17 , wherein the protective sheath has an upper helical section and a lower helical section, wherein the upper helical section is formed in a first circumferential direction about a vertical axis defined by the cylindrical cavity and the lower helical section is formed in a second circumferential direction about a vertical axis that is opposite the first circumferential direction.
20 . The extension joint device according to claim 19 , wherein the upper helical section extends from a top end that is fixed relative to the vertical axis to a bottom end that is connected to the lower helical section;
wherein the lower helical section extends from a top end that is connected to the lower end of the upper helical section to a bottom end of the lower helical section that is fixed relative to the vertical axis; and
wherein extension and retraction of the second cylinder relative to the first cylinder causes a connection point between the upper helical section and the lower helical section to move about the vertical axis in the first circumferential direction and the second circumferential direction, respectively.