초록 ▼

A two part fastener of the lockbolt type is provided in which the pintail portion is provided with a rollback type land immediately adjacent the breakneck groove having a diameter generally no greater than the root diameter of the pull grooves provided thereon. This reduced diameter rollback type la

A two part fastener of the lockbolt type is provided in which the pintail portion is provided with a rollback type land immediately adjacent the breakneck groove having a diameter generally no greater than the root diameter of the pull grooves provided thereon. This reduced diameter rollback type land prevents the separated pintail from interfering with operation of the tool jaws during setting of a subsequent fastener so as to enable the length of the pintail to be reduced to a minimum thereby reducing the cost of materials while enabling use of conventional installation tools.

대표청구항 ▼

A two part fastener for securing a plurality of workpieces together comprising a pin member and a collar member, said pin member being made of an exotic material such as titanium alloy and having an elongated shank portion terminating on one end in an enlarged head, said shank portion having a plura

A two part fastener for securing a plurality of workpieces together comprising a pin member and a collar member, said pin member being made of an exotic material such as titanium alloy and having an elongated shank portion terminating on one end in an enlarged head, said shank portion having a plurality of lock grooves, a pintail portion and a breakneck groove between said lock grooves and said pintail portion, said pintail portion having a plurality of pulling grooves and a rollback land disposed between and immediately adjacent each of said breakneck groove and said pulling grooves, said collar member being adapted to be located on said shank portion in surrounding relationship with said lock grooves and adapted to be swaged into engagement with said lock grooves by action of a pulling tool, the pulling tool having multitooth jaw means for engaging said pulling grooves and an anvil for engaging and swaging said collar, said jaw means being of a non-self-releasing structure and being actuable from a forwardmost position in which it engages said pulling grooves to a readwardmost position, said collar being swaged by said anvil in response to relative movement of said jaw means from said forwardmost position toward said rearwardmost position, and said pulling tool being further operative in said relative movement to separate said pintail portion from said shank portion at said breakneck groove subsequent to said collar being swaged, said severed pintail being moved at least partially axially through said jaw means in response to application of said jaw means to a pin member of a subsequent fastener and by engagement of its severed end with the shank portion of such pin member of said subsequent fastener, said rollback land having a diameter generally no greater than the root diameter of said pulling grooves and wherein said pintail portion has a maximum length generally defined by the formula A≤B-C wherein A is the length of said pintail portion measured from the terminal end thereof to approximately the juncture point between said breakneck groove and said rollback land, B is the distance from the collar engaging sheet line of said workpieces to the most distant pintail engaging portion of said jaw means when said jaw means are in said forwardmost position and said anvil is in initial engagement with said collar member and C is the distance from the collar engaging sheet line to approximately the juncture point between said breakneck groove and said rollback land.