초록 ▼

An axially extensible and retractable structure including a plurality of cylindrical, threadedly engaged elements rotatable relative to one another for movement between axially extended and retracted positions together with a plurality of non-rotatable, telescoping segments. Preferably, none of the

An axially extensible and retractable structure including a plurality of cylindrical, threadedly engaged elements rotatable relative to one another for movement between axially extended and retracted positions together with a plurality of non-rotatable, telescoping segments. Preferably, none of the threads is exposed on the outside of the structure as the elements are moved between their extended and retracted positions. The structure is described in several embodiments, some with the telescoping segments positioned within the threaded elements, and some with the threaded elements within the segments which, in one embodiment, is adapted to support another element such as a boat sail, along its axial length. Also disclosed is a preferred method for fabricating the threaded elements utilizing relatively strong, light-weight materials such as carbon fiber impregnated with a curable epoxy resin.

대표청구항 ▼

1. A telescoping, axially extensible and retractable structure comprising: a) a first, hollow, tube-like member having internal and external walls and elongated on a central axis between first and second ends; b) first stop means extending inwardly from said internal wall of said first member ad

1. A telescoping, axially extensible and retractable structure comprising: a) a first, hollow, tube-like member having internal and external walls and elongated on a central axis between first and second ends; b) first stop means extending inwardly from said internal wall of said first member adjacent said first end; c) means defining a first, helical thread on said internal wall of said first member extending substantially from said second end to said first stop means; d) a second, hollow, tube-like member, positioned at least partially within said first member, having internal and external walls and elongated on said central axis between third and fourth ends; e) means defining a second, helical thread on said external wall of said second member extending substantially from said fourth end to a predetermined position less than half the distance to said third end, said first and second threads being mutually engaged for relative axial movement of said first and second members in response to relative rotation thereof; f) second stop means extending inwardly from said external wall of said second member adjacent said predetermined position; and g) means for effecting relative rotation of said first and second members to produce said relative axial movement thereof between a relatively retracted position, wherein said second and fourth ends are substantially adjacent one another, and a relatively extended position, wherein said first and second stop means are in mutual contact, whereby both said first and second threads remain externally unexposed throughout the range of said relative axial movement of said first and second members. 2. The invention according to claim 1 and further comprising: a) third stop means extending inwardly from said internal wall of said second member adjacent said third end; b) means defining a third, helical thread on said internal wall of said second member extending substantially from said fourth end to said second stop means; c) a third, tube-like member, positioned at least partially within said second member, having an external wall and elongated on said central axis between fifth and sixth ends; d) means defining a fourth, helical thread on said external wall of said third member extending substantially from said sixth end to a fixed position less than half the distance to said fifth end, said third and fourth threads being mutually engaged for relative axial movement of said second and third members in response to relative rotation thereof; e) fourth stop means extending inwardly from said external wall of said third member adjacent said fixed position; and f) means for effecting relative rotation of said second and third members to produce said relative axial movement thereof between a relatively retracted position, wherein said fourth and sixth ends are substantially adjacent one another, and a relatively extended position, wherein said second and third stop means are in mutual contact, whereby both said third and fourth threads remain externally unexposed throughout the range of said relative axial movement of said second and third members. 3. The invention according to claim 2 and further including a payload supported upon said fifth end. 4. The invention according to claim 3 wherein said central axis is substantially vertical, whereby said payload is moved between lowered and raised positions during said relative axial movement of said first, second and third members. 5. The invention according to claim 4 and further including means defining an internal passageway extending between said fourth and fifth ends, and a flexible cable extending through said passageway. 6. The invention according to claim 5 wherein said payload comprises electrical apparatus and said cable effects an electrical connection to said electrical apparatus. 7. The invention according to claim 1 wherein said first member is reciprocally rotatable, and further comprising means for restraining rotation of said second member. 8. The invention according to claim 7 and further comprising a multi-segment, telescoping tube, elongated on said central axis, extending between a fixed end and a movable end, and further including means connecting said movable end to said third end. 9. The invention according to claim 8 wherein said tube is non-rotatable, and said means for restraining rotation of said second member comprises said tube and the connection of said movable end thereof to said third end. 10. The invention according to claim 9 and further including a flexible cable extending through said tube. 11. The invention according to claim 10 wherein said tube is positioned substantially entirely within said second member when said first and second members are in said relatively retracted position. 12. The invention according to claim 10 and further including electrical apparatus supported on and movable with said movable end of said tube, and wherein said cable provides an electrical connection to said electrical apparatus.