Back to results
US 4,389,145 AGranted
Method of tapping dual thread fasteners
AssigneeRussell, Burdsall & Ward Corporation
InventorTerry D. Capuano
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeRussell, Burdsall & Ward Corporation
InventorTerry D. Capuano
Estimating the term…
An internally threaded fastener, such as a nut, includes a body having an axially extending opening with a side wall. A coarse internal thread convolution is formed in the side wall of the nut body. A fine thread convolution is also formed in the side wall of the nut body. The turns of the coincident coarse and fine thread convolutions are intermingled to enable them to engage a fastener having either a coarse or a fine external thread. An improved tap has a first section for forming the fine thread convolution and a second section for forming the coarse thread convolution. The two sections of the tap are interconnected in a coaxial relationship by a connector section having an axial extent which is less than the axial extent of the coincident coarse and fine thread convolutions. When a plurality of nuts are to be tapped, the fine thread convolution is tapped first. This enables a leading nut to be moved away from a following nut during tapping of a coarse thread convolution in the leading nut and the tapping of a coarse thread convolution in the following nut.
A method of forming an internally threaded fastener having coincident coarse and fine thread convolutions with intermingled turns, said method comprising the steps of providing a body having an axially extending opening, providing a single tap having a first section for forming a thread convolution with a first pitch and a second section axially aligned with the first section for forming a thread convolution with a second pitch which is different than the first pitch, tapping in the side wall of the opening with the first section of the tap a first internal thread convolution having the first pitch by effecting axial movement between the tap and the body, and thereafter tapping in the side wall of the opening a second internal thread convolution of the second pitch coincident with the first thread convolution and having turns intermingled with turns of the first thread convolution, said step of tapping a second thread convolution being performed with the second section of the single tap by continuing the axial movement between the tap and the body.
A method of sequentially tapping a plurality of nut bodies having axial openings extending through the nut bodies, said method comprising the steps of providing a tap having a first section for forming a thread convolution with a first pitch and a second section for forming a thread convolution with a second pitch which is greater than the first pitch, moving a first nut body and the tap axially relative to each other at a first speed while forming a thread convolution having the first pitch in the first nut body with the first section of the tap, moving a second nut body and the tap axially relative to each other at the first speed while forming a thread convolution having the first pitch in the second nut body with the first section of the tap, and moving the first nut body axially away from the second nut body by moving the first nut body and the tap axially relative to each other at a second speed which is greater than the first speed while forming a thread convolution having the second pitch in the first nut body with the second section of the tap and while continuing to form a thread convolution having the first pitch in the second nut body with the first section of the tap.
Dependencies are inferred from the claim text.