Blind rivet setting system and method for setting a blind rivet then verifying the correctness of the set

A system for setting a blind rivet and evaluating the acceptability of the set, said rivet being of the type having a frangible tubular body and an elongated mandrel that includes an enlarged head and a stem extending rearwardly of the head and through said frangible tubular body, said system comprising:

• a blind rivet setting tool, said tool including a body, said body having a long axis, said tool having a mandrel engaging mechanism for engaging said stem of said mandrel, said engaging mechanism being reciprocable in the axial direction along said long axis of said body, said tool further including force applying means for acting on said engaging mechanism to forcibly move said mechanism in said axial direction to cause the head of the mandrel to deform the tubular body and create a secondary head and to thereafter break the stem of the mandrel from the head and complete the rivet setting process;
• a transducer operatively associated with said tool for measuring the force applied by said force applying means to move said engaging mechanism during the rivet setting process and producing a series of force output signals related thereto including a first force output signal at a first interval of the rivet setting process and a second force output signal at a second interval of said setting process;
• and
• a control circuit for receiving said first and second force output signals and determining the difference therebetween and comparing said determined difference with a predetermined desired value.

A system for setting a blind rivet and evaluating the acceptability of the set, said rivet being of the type having a frangible tubular body and an elongated mandrel that includes an enlarged head and a stem extending rearwardly of the head and through said frangible tubular body, said system comprising:

• a blind rivet setting tool, said tool including a body, said body having a long axis, said tool having a mandrel engaging mechanism for engaging said stem of said mandrel, said engaging mechanism being reciprocable in the axial direction along said long axis of said body, said tool further including a piston assembly operatively connected to said engaging mechanism to forcibly move said mechanism in said axial direction to cause the head of the mandrel to deform the tubular body and create a secondary head and to thereafter break the stem of the mandrel from the head and complete the rivet setting process;
• a transducer for measuring the movement of said engaging mechanism in said axial direction and producing a first displacement output signal related to the position of said engaging mechanism at a first interval of the setting process and a second displacement output signal related to the position of said engaging mechanism at a second interval of the setting process;
• and
• a control circuit for receiving said first and second displacement output signals and determining the difference therebetween and comparing the determined difference with a predetermined desired value.

A method for setting a blind rivet having a mandrel defining an axis and for evaluating the acceptability of the set, said method including the steps of:

• engaging the mandrel with an axially moveable mandrel engaging mechanism;
• setting the blind rivet in a desired position by forcibly displacing the mandrel engaging mechanism in the axial direction;
• measuring the force applied to said mandrel engaging mechanism during the setting process;
• measuring the axial displacement of said mandrel engaging mechanism during said setting process;
• determining the total energy used during said rivet setting process from said force and displacement measurements;
• and
• comparing the determined total energy with a predetermined desired value.

A method for setting a blind rivet having a mandrel and for evaluating the acceptability of the set, said method including the steps of:

• setting a blind rivet in a desired position with a blind rivet setting tool, said tool having a mandrel engaging mechanism for forcibly driving the mandrel;
• measuring the force of said mandrel engaging mechanism applied to said mandrel of said blind rivet at a first interval of the setting process;
• measuring the force of said mandrel engaging mechanism applied to said mandrel of said blind rivet at a second interval of said setting process;
• determining the difference between said force applied at said first interval and said force applied at said second interval;
• and
• comparing said determined force difference with a predetermined desired value.

A method for setting a blind rivet having a mandrel and for evaluating the acceptability of the set, said method including the steps of:

• setting a blind rivet in a desired position with a blind rivet setting tool, said tool having an axially movable mandrel engaging mechanism for forcibly driving the mandrel in the axial direction;
• measuring the axial movement of said mandrel engaging mechanism between a first interval of said setting process and a second interval of said process;
• and
• comparing the measured movement with a predetermined desired value.