Apparatus for tightening threaded fasteners

Abstract

According to a first aspect of the invention we provide an apparatus for torsionally coupling a threaded fastener and a torque output device including:—a first coupling member: rotatably and threadedly engagable with the threaded fastener; rotatably and taperedly engagable with a second coupling member; non-rotatably engagable with an action portion of the torque output device; the second coupling member non-rotatably engagable with a reaction portion of the torque output device; and wherein the first coupling member, when rotated by the action portion of the torque output device, applies a load to the threaded fastener. Advantageously apparatus with alternative geometries for torsion coupling allow for more efficiently and evenly distributed load stress distribution; higher torsion strength; and lower fastener mass and volume.

What is claimed is: 
     
         1 - 14 . (canceled) 
     
     
         15 . An apparatus for coupling a threaded fastener and a torque input device including:
 a first coupling member having a tapered external surface; and   a second coupling member having an inversely tapered internal surface non-rotatably engagable with the tapered external surface of the first coupling member.   
     
     
         16 . An apparatus according to  claim 15  wherein a load bearing surface area between the first and the second coupling members is increased without increasing the diameter of the apparatus. 
     
     
         17 . An apparatus according to  claim 15  claim wherein a load bearing surface area between the first and the second coupling members is in three dimensional space rather than a two dimensional plane. 
     
     
         18 . An apparatus according to  claim 15  wherein the tapered external surface of the first coupling member and the inversely tapered internal surface of the second coupling member are angled. 
     
     
         19 . An apparatus according to  claim 15  wherein the tapered external surface of the first coupling member and the inversely tapered internal surface of the second coupling member are shaped as frustums of an angled stepped cone. 
     
     
         20 . An apparatus according to  claim 15  wherein the tapered external surface of the first coupling member and the inversely tapered internal surface of the second coupling member are shaped as frustums of an angled stepped cone having variable step quantities, dimensions, geometries, angles and/or intervals. 
     
     
         21 . An apparatus according to  claim 15  wherein the first coupling member substantially surrounds the second coupling member. 
     
     
         22 . An apparatus according to  claim 15  wherein the torque input device is either pneumatically, electrically, hydraulically or manually driven. 
     
     
         23 . An apparatus according to  claim 15  wherein the first coupling member is non-rotatably engagable with an action portion of a torque input device. 
     
     
         24 . An apparatus according to  claim 15  wherein the second coupling member, when rotated by an action portion of the torque input device, applies a load to the threaded fastener. 
     
     
         25 . An apparatus for coupling a torque input device and a threaded fastener of the kind having a shank with a tapered axial bore, the apparatus including a coupling member having an inversely tapered external surface, non-rotatably engagable with the tapered axial bore of the threaded fastener. 
     
     
         26 . A geometry for coupling a threaded fastener and a torque input device including:
 a first coupling member having a tapered external surface; and   a second coupling member having an inversely tapered internal surface non-rotatably engagable with the tapered external surface of the first coupling member.