Flexible shaft for transfer of rotary motion

Abstract

A flexible shaft, having a first end and, a second end and capable of being bent about its axis while transferring rotary motion from a device to tool is disclosed. The shaft, manufactured from a rigid material, has at least one flexible segment having two sinuous slots ascending in a helical path from a common start point in opposite rotational directions. In other segments the slots can be a single helical slot, double helical slots, parallel or crossing, or circumferential. The helical paths can vary within each segment or from segment to segment.

What is claimed is: 
     
         1 . A flexible shaft, said flexible shaft being a rigid material and comprising:
 a. a rigid first end, said rigid first end being capable of receiving an instrument to impart rotary motion,   b. a rigid second end, said rigid second end being dimensioned to receive a tool to receive and transmit said rotary motion,   c. a body between said rigid first end and said rigid second end, said body having:
 an outer surface, 
 an inner cavity having a surface, 
 a longitudinal surface, 
 at least one segment, each of said at least one segment having a segment proximal end and a segment distal end, 
 at least two helical sinuous slots within at least one of said at least one segment, each of said at least two helical sinuous slots forming interlocking teeth and having:
 a width, 
 a depth from said outer surface to said inner cavity, 
 a common start point, said common start point having a circular end, said start point being a first predetermined distance from said rigid first end, and 
 at least one end point, each of said at least one end point having a circular end, said at least one end point being a second predetermined distance from said rigid first end, 
 
 a first of said at least one segment having said at least two helical sinuous slots cut in a helical sinuous path along said longitudinal surface of said first of said at least one segment and ascending in a first direction, a first of said helical sinuous slots ascending from said common start point in a first rotational direction and a second of said helical sinuous slots ascending from said common start point in a second rotational direction, said helical sinuous slots crossing paths along said longitudinal surface to enable flexibility within said at least one segment, 
   wherein said rotary motion is transferred by said interlocking teeth locking with adjacent teeth to transfer said rotary motion from said rigid first end to said rigid second end while said body is unbent or bent about an axis.   
     
     
         2 . The flexible shaft of  claim 1  wherein a third helical slot ascends another of said at least one segment in a helical path along said longitudinal surface from a first start point to a first end point in first a rotational direction. 
     
     
         3 . The flexible shaft of  claim 2  wherein an unslotted segment separates said first of said at least one segment and said another of said at least one segment. 
     
     
         4 . The flexible shaft of  claim 1  wherein said end point is a single point. 
     
     
         5 . The flexible shaft of  claim 1  wherein said end point is multiple points spaced from one another 
     
     
         6 . The flexible shaft of  claim 2  further comprising a fourth helical slot ascending said another of said at least one segment from a second start point to a second end point in said first rotational direction, said first start point and said second start point and said first end point and said second end point being spaced from one another and said fourth helical slot ascending in a path parallel to said third helical slot. 
     
     
         7 . The flexible shaft of  claim 6  wherein an unslotted segment separates said first of said at least one segment and said another of said at least one segment. 
     
     
         8 . The flexible shaft of  claim 1  wherein another of said at least one segment comprises multiple circumferential sinuous slots, each of said multiple circumferential sinuous slots having a start point and an end point. 
     
     
         9 . The flexible shaft of  claim 8  wherein an unslotted segment separates said first of said at least one segment and said another of said at least one segment. 
     
     
         10 . The flexible shaft of  claim 1  wherein another of said at least one segment comprises a pair of helical sinuous slots cut along said longitudinal surface, ascending in a first direction, said pair of said helical sinuous slots ascending from a common start point, a first of said pair of helical sinuous ascending in a first rotational direction and a second of said pair of helical sinuous slots ascending in a second rotational direction, said helical sinuous slots crossing paths along said longitudinal surface to enable flexibility within said another of said at least one segment. 
     
     
         11 . The flexible shaft of  claim 10  wherein an unslotted segment separates said first of said at least one segment and said another of said at least one segment. 
     
     
         12 . The flexible shaft of  claim 1  wherein another of said at least one segment comprises a pair of helical sinuous slots cut along said longitudinal surface, ascending in a second direction from said common start point, a first of said pair of helical sinuous slots ascending in a first rotational direction and a second of said pair of helical sinuous slots ascending in a second rotational direction, said helical sinuous slots crossing paths along said longitudinal surface to enable flexibility within said another of said at least one segment. 
     
     
         13 . The flexible shaft of  claim 1  wherein each of said at least one sinuous slot has a helical angle from the group of about 30 to 85 degrees from the longitudinal axis or about 45 to 75 degrees from the longitudinal axis 
     
     
         14 . The flexible shaft of  claim 1  wherein at least one of said at least one sinuous slot has a depth perpendicular to a plane tangent to the outer surface of said body. 
     
     
         15 . The flexible shaft of  claim 1  wherein at least one of said at least one sinuous slot has a depth at an angle with a plane tangent to the outer surface to form an undercut. 
     
     
         16 . The flexible shaft of  claim 1  wherein said angle is in the range of about one to about 75 degrees. 
     
     
         17 . The flexible shaft of  claim 1  wherein said angle is in the range of about 30 to about 45 degree 
     
     
         18 . The flexible shaft of  claim 1  wherein at least one of said at least one sinuous slot has a width of about 0.005 to about 0.25 inches. 
     
     
         19 . The flexible shaft of  claim 1  wherein at least one of said at least one sinuous slot has a width of about 2.5% to about 20% of a diameter of said body. 
     
     
         20 . A flexible shaft, said flexible shaft being a rigid material and comprising:
 a. a rigid first end, said rigid first end being capable of receiving an instrument to impart rotary motion,   b. a rigid second end, said rigid second end being dimensioned to receive a tool to receive and transmit said rotary motion,   c. a body between said rigid first end and said rigid second end, said body having: an outer surface,
 an inner cavity having a surface, 
 a longitudinal surface, 
 at least one segment, each of said at least one segment having a segment proximal end and a segment distal end, 
 at least two helical sinuous slots within at least one of said at least one segment, each of said at least two helical sinuous slots forming interlocking teeth and having:
 a width, 
 a depth from said outer surface to said inner cavity, 
 a common start point, said common start point having a circular end, said start point being a first predetermined distance from said rigid first end, and 
 at least one end point, each of said at least one end point having a circular end, said at least one end point being a second predetermined distance from said rigid first end, 
 a first of said at least one segment having two helical sinuous slots cut in a helical sinuous path along said longitudinal surface of said first of said at least one segment and ascending in a first direction, a first of said helical sinuous slots ascending from said common start point in a first rotational direction and a second of said helical sinuous slots ascending from said common start point in a second rotational direction, said helical sinuous slots crossing paths along said longitudinal surface to enable flexibility within said at least one segment, 
 a second of said at least one segment have at least one sinuous slot, each of said at least one sinuous slot being selected from the group comprising multiple circumferential slots, single helical sinuous slot, multiple parallel helical sinuous slots having spaced start points and end point, two helical sinuous slots having a single start point and a single end point, two helical sinuous slots having a single start point and two spaced end point, two helical sinuous slots ascending from said common start point with opposing rotational directions or said first of said at least one segment and said second of said at least one segment being separated by an unslotted segment, 
 
   wherein said rotary motion is transferred by said interlocking teeth locking with adjacent teeth to transfer said rotary motion from said rigid first end to said rigid second end while said body is unbent or bent about an axis.