Method and apparatus for fillet formation under the head of a headed pin type fastener

In a pin type structure having an elongated pin shank with an enlarged pin head at one end, apparatus for rolling a fillet radius at the juncture of the pin head and pin shank, said apparatus comprising:

• a roller assembly,
• a pin feeder, and
• a push rod assembly,
• said roller assembly including a plurality of roller subassemblies,
• each of said roller subassemblies including a rotatably supported roller,
• said roller having a generally circular contour and terminating at its radially outer end in a circumferential arcuate tip having a contour for forming the fillet radius,
• said roller subassemblies adapted to be mounted with said rollers oriented to define an input opening having a central axis for receiving the pin shank with said rollers engaging the juncture at the pin head and pin shank,
• said pin feeder operatively associated with said roller assembly and having an outlet end locatable substantially in line with said central axis of said input opening to periodically have a pin moved into said input opening,
• said push rod assembly operatively associated with said roller assembly and including a push rod adapted to be moved along said central axis into engagement with the pin head when located in said input opening,
• said push rod being rotatable and adapted to engage the pin head at a preselected magnitude of force against said arcuate tips of said rollers and to rotate the pin at a preselected speed of rotation whereby the fillet radius is roll formed by said arcuate tips at the juncture of the pin head and pin shank,
• said push rod assembly including load means for selectively setting the desired magnitude of rolling force applied by said push rod against the head of the pin in roll forming the fillet,
• said push rod assembly including load detection means for measuring the magnitude of the rolling force applied by said push rod against the head of the pin in roll forming the fillet and in providing a reject signal whereby a pin on which the measured rolling force is outside of a preselected range of the rolling force will be rejected.

In a pin type structure having an elongated pin shank with an enlarged pin head at one end and having a final fillet radius of a preselected contour at the juncture of the pin head and pin shank,

• said pin structure with said final fillet radius being produced by the process including the steps of:
• forming a pin blank having an enlarged pin shank with an enlarged pin head at one end and an initial fillet radius at the juncture of the pin shank and pin head of the pin blank,
• said process comprising the steps of providing rolling apparatus including:
• a roller assembly, and a push rod assembly,
• providing said roller assembly to have a plurality of roller subassemblies with each of said roller subassemblies including a rotatably supported roller,
• each of said rollers having a generally circular contour and terminating at its radially outer end in a circumferential arcuate tip having a contour for forming said final fillet radius by engagement with said initial fillet radius,
• locating said roller subassemblies with said rollers oriented to define an input opening having central axis for receiving the pin shank with said rollers engaging said initial fillet radius at the juncture of the pin head and pin shank,
• providing said push rod assembly with a rotatable push rod adapted to be moved along said central axis into engagement with the pin head when said pin blank is located in said input opening,
• actuating said push rod to engage the pin head at a preselected magnitude of force against said arcuate tips of said rollers as engaged with said initial fillet radius and to rotate said pin blank at a preselected speed of rotation whereby said final fillet radius is roll formed by said arcuate tips at the juncture of said pin head and said pin shank,
• measuring the magnitude of the rolling force applied by said push rod against the head of the pin for roll forming the final fillet radius and in providing a reject signal where a pin blank on which the measured rolling force is outside of a preselected range of the rolling force.

In a pin type structure having an elongated pin shank with an enlarged pin head at one end, apparatus for rolling a fillet radius at the juncture of the pin head and pin shank, said apparatus comprising:

• a roller assembly,
• said roller assembly including at least three roller subassemblies,
• each of said roller subassemblies including a rotatably supported roller,
• said roller having a generally circular contour and terminating at its radially outer end in a circumferential arcuate tip having a contour for forming the fillet radius,
• said roller subassemblies adapted to be mounted with said rollers oriented to define an input opening having a vertical axis for receiving the pin shank with said rollers engaging the juncture at the pin head and pin shank,
• adjustable support means for holding said roller subassemblies in a preselected orientation relative to each other to provide said arcuate tips at said outlet with a predetermined diameter for rolling the fillet radius on a pin shank of a predetermined diameter, said support means having adjustment means operatively connected with said roller subassemblies whereby said roller subassemblies can be simultaneously moved in unison to vary the magnitude of the preselected diameter for rolling the fillet radius on pin shanks of different diameters.

In a pin type structure having an elongated pin shank with an enlarged pin head at one end, apparatus for rolling a fillet radius at the juncture of the pin head and pin shank said apparatus comprising:

• a roller assembly,
• said roller assembly including at least three roller subassemblies,
• each of said roller subassemblies including a rotatably supported roller,
• said roller having a generally circular contour and terminating at its radially outer end in a circumferential arcuate tip having a contour for forming the fillet radius,
• said roller subassemblies adapted to be mounted with said rollers oriented to define an input opening having a central axis for receiving the pin shank with said roller engaging the juncture at the pin head and pin shank,
• adjustable support means for holding said roller subassemblies in a preselected orientation relative to each other to provide said arcuate tips at said outlet with a predetermined diameter for rolling the fillet radius on a pin shank of a predetermined diameter, said support means having adjustment means operatively connected with said roller subassemblies whereby said roller subassemblies can be simultaneously moved in unison to vary the magnitude of the preselected diameter for rolling the fillet radius on pin shanks of different diameters.

In a pin type structure having an elongated pin shank with an enlarged pin head at one end, apparatus for rolling a fillet radius at the juncture of the pin head and pin shank, said apparatus comprising:

• a roller assembly,
• said roller assembly including a plurality of roller subassemblies,
• each of said roller subassemblies including a rotatably supported roller,
• said roller having a generally circular contour and terminating at its radially outer end in circumferential arcuate tip having a contour for forming the fillet radius,
• said roller subassemblies adapted to be mounted with said rollers oriented to define an input opening having a vertical axis for receiving the pin shank with said rollers engaging the juncture at the pin head and pin shank,
• each of said rollers of said roller subassemblies including adjustment means pivotally supporting each said roller for selective adjustment of the angle of the longitudinal plane of each of said rollers relative to a plane transverse to the axis of said opening,
• said adjustment means providing adjustment of said angle over a range of from around 22° to around 40°.