Fiber optic rotary coupling and devices
First Claim
Patent Images
1. A retractor/dispenser system for optical fiber cable, in which the cable is continuous and kept at a radius of curvature in excess of an established minimum, the system comprising:
- a housing having a central axis and including a first outlet port for withdrawing and returning optical cable from the housing, and a second outlet port for a fixed end of the optical cable;
a rotatable cable spool concentric with a central axis in the housing, the cable spool having an annular surface for winding optical fiber thereon, the annular surface having a radius of curvature at least greater than the minimum bending radius;
at least one fiber optic cable wrapped around the periphery of the annulus and including at least one cable end extending through the first port, the wrapped cable having an insulated jacket section extending with optical continuity to a section of substantially smaller diameter at a transition region;
an interleaved and co-extensive length of coil spring and length of smaller diameter cable coupled to the transition region of the cable, and wrapped about the spool, the lengths of the wrapped spring and cable alternating radially within the interleaved structure which is helically concentric with the central axis, one end of the spring being fixed to the spool at one radius and the other being coupled to the housing at a greater radius from the central axis, such that the interleaved cable/spring structure provides, by expansion or contraction of the helical form between the coupled ends, a variable length of cable for accommodating changes due to rotation of the spool as cable is extracted at the first port, andanother section of cable coupled with optical continuity to the fixed end to the interleaved spring/cable combination and extending from the housing at the second port to provide a fixed end for external interconnection.
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Abstract
In this invention, a fiber optic rotary joint and applications of such to retractable fiber optic cables is described. The fiber optic rotary joint consists of a spiral arrangement of a spring and optical fiber pair placed between rotating inner and outer diameters. The fiber optic rotary joint provides a finite number of turns of a fiber optic cable about a primary axis. These turns can be used, for example, with a rotating spool to provide a continuous retractable and extendable cable.
194 Citations
22 Claims
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1. A retractor/dispenser system for optical fiber cable, in which the cable is continuous and kept at a radius of curvature in excess of an established minimum, the system comprising:
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a housing having a central axis and including a first outlet port for withdrawing and returning optical cable from the housing, and a second outlet port for a fixed end of the optical cable; a rotatable cable spool concentric with a central axis in the housing, the cable spool having an annular surface for winding optical fiber thereon, the annular surface having a radius of curvature at least greater than the minimum bending radius; at least one fiber optic cable wrapped around the periphery of the annulus and including at least one cable end extending through the first port, the wrapped cable having an insulated jacket section extending with optical continuity to a section of substantially smaller diameter at a transition region; an interleaved and co-extensive length of coil spring and length of smaller diameter cable coupled to the transition region of the cable, and wrapped about the spool, the lengths of the wrapped spring and cable alternating radially within the interleaved structure which is helically concentric with the central axis, one end of the spring being fixed to the spool at one radius and the other being coupled to the housing at a greater radius from the central axis, such that the interleaved cable/spring structure provides, by expansion or contraction of the helical form between the coupled ends, a variable length of cable for accommodating changes due to rotation of the spool as cable is extracted at the first port, and another section of cable coupled with optical continuity to the fixed end to the interleaved spring/cable combination and extending from the housing at the second port to provide a fixed end for external interconnection. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for controllably rotating a length of optical fiber cable to extract and rewind the cable, while maintaining optical continuity and avoiding excessive stress and optical distortion in the cable, comprising:
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a base unit disposed about an axis and including a surface for a helically looped optical cable disposed about the central axis; a rotatable body concentric with the axis of the base unit and rotatable with respect thereto, the rotatable body having a concentric surface with greater than a predetermined minimum radius for winding optical fiber thereon; an interleaved structure comprising a length of coil spring and a cable length having multiple turns wound about the central axis and disposed in the base unit, the interleaved structure being helically wound on the rotatable body about the central axis with the turns of spring and cable disposed in radially alternating turns, one end of the interleaved structure being fixed to the base unit at a given radius from the axis and the other end being coupled to the rotatable body at a radius greater than the given radius, and the interleaved structure being free to expand and contract circumferentially in response to angular displacement. - View Dependent Claims (9, 10, 11)
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12. A cartridge system for supplying and retracting jacketed optical fiber cable while maintaining optimal continuity along the optical fiber between a fixed port and a supply/extraction port on the cartridge, comprising:
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a housing having an outer periphery including at least one spaced apart fiber cable port, one of which is a control port for extraction and retraction of cable; a shaft disposed along a central axis in the housing and coupled to the housing; a cable spool within the housing rotatable about said shaft, the spool including a cable winding support annulus concentric with the central axis and having a radius from the central axis greater than a predetermined minimum bending radius for the optical fiber; the cable spool also including a pair of spaced apart generally planar elements transverse to the central axis and comprising a reel body having a perimeter with ratchet teeth and a reel cover spaced apart from a superior side of the reel body, the reel body including an inner transition aperture extending between superior and inferior surfaces of the reel body and within the annulus; a power spring helically wrapped about the central axis within the annulus and having a fixed end engaged to the shaft and a movable end engaged to the annulus; the system also including an annular mandrel on the inferior side of the cable spool and concentric with the central axis, the mandrel having a radius from the central axis that is greater than the predetermined minimum bending radius; a spiral spring adjacent the inferior side of the reel body and disposed about the mandrel, the spiral spring being coupled at one end to the mandrel and at a second end to the reel body adjacent its perimeter; an optical cable including a number of varying diameter sections that are optically continuous and include a first section of jacketed fiber wrapped about the annulus; a second section of the optical fiber cable being a small diameter section, unjacketed or with a small diameter cover, and interleaved with the spiral spring along its length between the end fixed to the mandrel and the end fixed to the reel body, the second section being coupled to the first via the transition port in the reel body; a number of separate attachment elements coupling the optical fiber to the spiral spring at spaced apart points therealong; a third section of optical fiber cable, the third section being jacketed and extending from the second section of fiber cable to provide a fixed optical fiber cable terminal; a pawl mechanism disposed to engage the ratchet teeth to retain the reel body in a selected angular position; wherein when the free end of the jacketed cable is withdrawn from the control port and cable is unwound from the spool, the spool rotation winds up the power spring at the same time that the spiral spring is wound to provide a compensating length of fiber within the housing by the variation in radius of the turns in the interleaved structure. - View Dependent Claims (13, 14, 15)
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16. In a retractable/extendable device for fiber optic lines, a rotation buffering unit for providing a variable length section of fiber optic line enabling extension and retraction with optical continuity, as fiber optic line is unwound from or wound upon the device, comprising:
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a body having a mandrel rotatable about a central axis, the mandrel having a radius from the central axis that is greater than a predetermined minimum bending radius for the optical fibers; an interleaved spring/optical fiber structure disposed on the body about the mandrel, the spring comprising a strip of compliant material helically wound about a central axis, the strip having a height-to-thickness ratio selected to provide a height substantially greater than the optical fiber thickness, the thickness of the spring being proportioned to the height of the strip material and its elasticity, to provide torque and spring compliance in selected ranges, the structure also including at least one optical fiber positioned coextensively along the helical spring at an intermediate height region thereof, and being affixed thereto at spaced apart locations along its length, one end of the spring being fixed to the body and the other end being coupled to a fixed point at a greater radial distance from the central axis than the mandrel, the spring and interleaved fiber combination being radially and circumferentially movable between limits outside the mandrel, whereby rotation of a length of fiber optic line coupled to an end of the interleaved structure is accommodated by radial expansion or tightening of the helical spring and interleaved fiber between the two ends thereof. - View Dependent Claims (17, 18, 19)
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20. A device for allowing bending of an optical fiber while maintaining more than a predetermined minimum allowable bending radius in the fiber between a pair of attachment points, comprising:
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a flat spring member having a high cross-sectional aspect ratio of height to thickness, and an intermediate region along the height dimension of the cross-section, the spring member being curvilinear and continuous along its length with greater than the minimum bending radius between the pair of attachment points, and at least one optical fiber disposed along the length of the spring member and attached thereto at intermediate regions of the height of the spring member, and spaced therealong, the spacings being such that the fiber curves between the pair of attachment points are no less than the minimum allowable bending radius despite lengthwise changes in the curvilinear shape of the spring member. - View Dependent Claims (21, 22)
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Specification