Patent ID: 6247883
Filing Date: 2001-06-19
Classification: F16B

Abstract:
A blind bolt for securing a plurality of workpieces at a desired clamp load with the workpieces having aligned openings therein and having an accessible side surface and a blind side surface and adapted to be installed by a relative axial force applied by an installation tool from the accessible side surface of the workpieces, said blind bolt comprising:a pin member having an elongated pin shank terminating at one end in an enlarged pin head, said pin head including a sleeve engaging surface on an underside thereof, an angle between said sleeve engaging surface and said elongated pin shank being between approximately 88-90.degree.;a generally elongated tubular sleeve adapted to receive said pin shank, said tubular sleeve including a first sleeve shank portion adapted to be located in the aligned openings in the workpieces and a second sleeve shank portion being located on said pin shank between said pin head and said first sleeve shank portion and arranged to engage said sleeve engaging surface of said pin head, said second sleeve shank portion having a band portion of a predetermined axial length, said band portion having a hardness less than the hardness of the first sleeve shank portion;engaging means operatively connected with said tubular sleeve and including an engaging structure adapted to be engaged by the installation tool whereby the relative axial force can be applied by the installation tool between said pin member and said engaging means to clamp the workpieces together at a relative axial force of a first magnitude;said second sleeve shank portion being radially deformable at said band portion between said pin head and the blind side surface of the workpieces in response to the relative axial force of a second magnitude less than said first magnitude to form an enlarged bulbed blind head for reacting against the blind side surface and a sleeve leg section extending between said blind head and said sleeve engaging surface for a preselected length;a load bearing means for transmitting the relative axial force of said second magnitude to said second sleeve shank portion through said first sleeve shank portion and responsive to a third magnitude of relative axial force less than said first magnitude and greater than said second magnitude with said first sleeve shank portion moving out of an axial load bearing relationship with said pin head whereby said blind head will engage the blind side surface such that said first magnitude of relative axial force and the final clamp load applied to the workpieces will be substantially between said pin, said blind head and said engaging means;said load bearing means adapted to be located generally externally of the aligned openings at the accessible side surface of the workpieces; securing means on said pin shank;said engaging means including an engaging structure operable with said securing means for connecting said pin member and said engaging structure together; andwherein said sleeve leg section expands radially outwardly upon application of the relative axial forces, said preselected length of said sleeve leg section being such that said sleeve leg section expands sufficiently to increase the length of a shear line through said blind head between the workpieces and said pin head to continuously include said preselected length of said sleeve leg section.