초록 ▼

The method of rivet installation creates a preload on the workpieces being joined. The installation steps include inserting a rivet into two or more workpieces to be joined and engaging the head of the rivet with an upper two piece tooling assembly while engaging the tail of the rivet with a counter

The method of rivet installation creates a preload on the workpieces being joined. The installation steps include inserting a rivet into two or more workpieces to be joined and engaging the head of the rivet with an upper two piece tooling assembly while engaging the tail of the rivet with a counterbore provided in a lower tool. In phase one of installation, which follows these engagement steps, the lower tool exerts a compressive force upon the rivet tail, thereby deforming the tail to form a lower upset head. In phase two of installation, an inner retractable pin of the two piece tooling assembly is withdrawn from contact with the rivet head while an outer ring tool of the tooling assembly exerts a compressive force upon peripheral portions of the rivet head, thereby deforming the rivet head periphery to form an enlarged rim comprising an upper upset head. This deformation of the rivet head periphery produces a preload. Both phase one and phase two of installation are executed in one continuous motion.

대표청구항 ▼

1. A method of installing a rivet to provide an axial preload on two or more workpieces joined by the rivet, the rivet having a shank, a head on one end of the shank and a tail on the other end of the shank, the method comprising the steps of: inserting the rivet tail and shank through aligned ho

1. A method of installing a rivet to provide an axial preload on two or more workpieces joined by the rivet, the rivet having a shank, a head on one end of the shank and a tail on the other end of the shank, the method comprising the steps of: inserting the rivet tail and shank through aligned holes in two or more stacked workpieces with the rivet tail extending beyond the face of one of the workpieces; providing a two piece tooling assembly comprising an outer tool and an inner tool, with said outer tool having an end face with a cylindrical opening therein in which said inner tool is slidably mounted, and positioning said two piece tooling assembly proximate the rivet head; providing a tool having a counterbore surface and positioning said counterbore surface proximate the rivet tail; engaging said rivet head with said tooling assembly such that said inner tool exerts an axially compressive force upon the rivet head and the outer tool exerts a compressive force upon peripheral portions of said rivet head, and engaging said rivet tail with said counterbore surface while said tool assembly engages said rivet head; deforming said rivet tail with an axially compressive force supplied thereto by said counterbore surface, said step of rivet tail deformation continuing until material comprising the rivet tail is deformed radially outwardly to form a first upset head having a diameter which is greater than that of the rivet shank and the diameter of the hole through the adjacent workpiece; discontinuing the axially compressive force applied to the rivet head by removing the inner tool from contact therewith while said outer tool and said counterbore surface continue to supply compressive force to said peripheral rivet head portions and said first upset head, respectively; and applying continued compressive force upon said peripheral rivet head portions using said outer tool until material comprising said peripheral rivet head portions begins to flow radially outwardly in a manner creating an enlarged rim about said rivet head; and increasing the compressive force upon the rim to further flatten and deform the peripheral rivet head portions, thereby forming a second upset head. 2. A method as set forth in claim 1, wherein the step of providing a tool having a counterbore surface includes providing a tool with a counterbore surface defined by one piece continuous surface. 3. A method as set forth in claim 1, further including the steps of: providing a rivet having a manufactured head of a predetermined thickness "X"; and spacing an end surface of the inner tool above the end face of the outer tool by a distance equal to "X" during execution of the steps of engaging said rivet head with said tooling assembly, engaging said rivet tail with said counterbore surface, and deforming said rivet tail to form the first upset head. 4. A method as set forth in claim 1, further including an initial step of providing a rivet having a top head portion that is larger in diameter than said shank, and a central head portion between said top head portion and said shank, said central head portion having a rim about its periphery that is larger in diameter than said top head portion and that is also larger in diameter than said shank. 5. A method as set forth in claim 4, wherein the step of engaging said rivet head with said tooling assembly includes the steps of contacting said rim with said outer tool and contacting said top head portion with said inner tool such that said inner tool is aligned concentrically with the aligned holes in said workpieces. 6. A method as set forth in claim 1, further including an initial step of providing a solid one-piece ductile rivet. 7. A method of installing a rivet to provide an axial preload on two or more workpieces joined by the rivet, the rivet having a shank, a head on one end of the shank and a tail on the other end of the shank, the method comprising the steps of: inserting the rivet tail and shank through aligned holes in two or more stacked workpieces with the rivet tail extending beyond the face of one of the workpieces; providing a two piece tooling assembly comprising an outer tool and an inner tool, with said outer tool having an end face with a cylindrical opening therein in which said inner tool is slidably mounted, and positioning said two piece tooling assembly proximate the rivet head; providing a tool having a counterbore surface and positioning said counterbore surface proximate the rivet tail; engaging said rivet head with said tooling assembly such that said inner tool exerts an axially compressive force upon the rivet head while the outer tool simultaneously exerts a compressive force upon peripheral portions of said rivet head, and engaging said rivet tail with said counterbore surface while said tool assembly simultaneously engages said rivet head; deforming said rivet tail with an axially compressive force supplied thereto by said counterbore surface, said step of rivet tail deformation continuing such as to cause material comprising the rivet tail to be deformed radially outwardly to form a first upset head having a diameter which is greater than that of the rivet shank and the diameter of the hole through the adjacent workpiece; continuing application of an axially compressive force supplied to said rivet tail by said counterbore surface such that rivet tail deformation allows said tool having a counterbore surface to contact the workpiece face through which said rivet tail extends; discontinuing the axially compressive force applied to the rivet head by removing the inner tool from contact therewith, said step of discontinuing being executed such that discontinuance of the axially compressive force occurs when the tool having a counterbore surface contacts said workpiece face; continuing to supply compressive force to said peripheral rivet head portions and said first upset head using said outer tool and said counterbore surface, respectively, while executing said discontinuing step; applying continued compressive force upon said peripheral rivet head portions using said outer tool until material comprising said peripheral rivet head portions begins to flow radially outwardly in a manner creating an enlarged rim about said rivet head; and increasing the compressive force upon the rim to further flatten and deform the peripheral rivet head portions, thereby forming a second upset head. 8. A method as set forth in claim 7, wherein the step of providing a tool having a counterbore surface includes providing a tool with a counterbore surface defined by a one piece continuous surface. 9. A method as set forth in claim 7, wherein the step of increasing the compressive force upon the rim includes forming a second upset head having an outside diameter, said outside diameter having a size that is relatable in a predictable manner to the amount of axial preload achieved. 10. A method of installing a rivet to provide an axial preload on two or more workpieces joined by the rivet, the rivet having a shank, a head on one end of the shank and a tail on the other end of the shank, the method comprising the steps of: inserting the rivet tail and shank through aligned holes in two or more stacked workpieces with the rivet tail extending beyond a first face of a first workpiece of the stacked workpieces and the rivet head protruding from a second face of a second workpiece of the stacked workpieces; providing a two piece tooling assembly comprising an outer tool and an inner tool with said outer tool having an end face with a cylindrical opening therein in which said inner tool is slidably mounted, and positioning said two piece tooling assembly proximate the rivet head and adjacent to said second face; providing a tool having a counterbore surface and positioning said counterbore surface proximate the rivet tail and adjacent to said first face; engaging said rivet head with said tooling assembly such that said inner tool exerts an axially compressive force upon the rivet head while the outer tool simultaneously exerts a compressive force upon peripheral portions of said rivet head, and engaging said rivet tail with said counterbore surface while said tooling assembly simultaneously engages said rivet head; deforming said rivet tail with an axially compressive force supplied thereto by said counterbore surface, said step of rivet tail deformation continuing such as to cause material comprising the rivet tail to be deformed radially outwardly to form a first upset head having a diameter which is greater than that of the rivet shank and the diameter of the hole through the adjacent workpiece; continuing application of an axially compressive force supplied to said rivet tail by said counterbore surface such that rivet tail deformation allows said tool having a counterbore surface to contact said first face; discontinuing the axially compressive force applied to the rivet head by removing the inner tool from contact therewith, said step of discontinuing being executed such that discontinuance of the axially compressive force occurs simultaneous with contact of the first face by the tool having a counterbore surface; continuing to supply compressive force to said peripheral rivet head portions and said first upset head using said outer tool and said counterbore surface, respectively, while executing said discontinuing step; applying continued compressive force upon said peripheral rivet head portions using said outer tool until material comprising said peripheral rivet head portions begins to flow radially outwardly in a manner creating an enlarged rim about said rivet head; and increasing the compressive force upon the rim to further flatten and deform the peripheral rivet head portions, thereby forming a second upset head; wherein said initial step of inserting the rivet through the workpiece includes the step of providing a solid one-piece ductile rivet that is not of a bi-metallic construction. 11. A method of installing a rivet as set forth in claim 10, wherein said step of providing a solid one-piece ductile rivet includes providing a rivet having a top head portion that is larger is diameter than said shank, and a central head portion between said top head portion and said shank, said central head portion having a rim about its periphery that is larger in diameter than said top head portion and that is also larger in diameter than said shank; and wherein said step of engaging the rivet head with the tooling assembly includes engaging the top head portion with the inner tool while simultaneously engaging the central head portion with the outer tool.