Self-plugging blind rivet

• US 5,248,231 A
• Filed: 10/08/1992
• Issued: 09/28/1993
• Est. Priority Date: 10/09/1991
• Status: Expired due to Term

• Current Assignee: Avdel Systems Limited (Fontana Luigi SpA)
• Original Assignee: Avdel Systems Limited (Fontana Luigi SpA)
• Inventors: Browne, Laurence A., Denham, Keith
• Primary Examiner(s): Wilson, Neill R.
• Application Number:
  US07/957,776
• Time in Patent Office: 355 Days
• Field of Search: 411/34-38, 411/43, 411/69, 411/70
• US Class Current: 411/43
• CPC Class Codes: F16B 19/1054 the pull-mandrel or the like being frangible

Abstract

A self-plugging blind rivet 10 comprises a tubular body 14 having a preformed head 34 at one end, and in the bore 36 of which a headed stem 12 is disposed. The stem 12 projects from the head 34 end of the body 14, and the head 18 of the stem 12 is substantially enclosed by a region 42 of the body 14 remote from the preformed head 34. The head 18 of the stem 12 abuts a shoulder 44 provided by a region 43 of the body 14 in which the diameter of the bore 36 is reduced and the wall is thickened. Axially spaced apart annular grooves 46, 48 in the external surface of the body 14 define between them a portion 50 which will collapse to form a blind head when the body 14 is compressed axially by pulling the stem 12 while supporting the preformed head 34. Finally, the stem head 18 may be pulled into the reduced diameter region 40 of the bore 36 and thereby cause the blind head to be reshaped and forced into compressive engagement with work being fastened. The stem head 18 remains securely enclosed by the body 14, whereby its loss is prevented.

Claims

1. A self-plugging blind rivet comprising a tubular rivet body and an elongate stem;

the body having an elongate shank, a radially enlarged pre-formed head at one end of the shank and an axial bore extending through the head and shank;

the stem comprising an elongate shank having a breakneck adjacent to one of its ends, and a radially enlarged stem head at the said one end, the breakneck dividing the stem into a stem-tail, and a plug including the stem head;

characterised in that the shank of the stem has a substantially constant diameter throughout its length, and the enlarged stem head has a diameter smaller than the external diameter of the shank of the body;

the shank of the body has a thin-walled portion adjacent to the pre-formed head, a thick-walled portion spaced from the pre-formed head by the thin-walled portion, and a counterbored portion extending from the thick-walled portion to the tail-end of the shank;

the bore of the body has a region of reduced diameter intermediate between its ends, in which the shank of the stem is a push-fit, a main region extending from the head end of the bore to the reduced region and in which the shank of the stem is clearance fit, and a counterbored region within the said counterbored portion of the shank and extending from the reduced region to the tail-end of the body, the shank of the body presenting an annular abutment face at the junction of the reduced and counterbored regions of the bore;

the stem head is disposed in the counterbored region and in abutment with the abutment face;

the external surface of the shank of the body is generally cylindrical, with the counterbored portion having been deformed so as to substantially enclose the head of the stem,

and the external surface of the shank of the body is provided with a narrow folding groove at a position intermediate between the pre-formed head and the thick-walled portion, and a stop groove in the thick-walled portion at a position close to that end of the thick walled portion nearest the thin-walled portion, the folding groove and the stop groove being spaced apart and defining a collapsible portion of the shank between them at which portion the shank will, under axial compression between the pre-formed head and the abutment face, collapse preferentially to form a blind head, whereby, on pulling the stem relative to the body to set the rivet in a workpiece, the collapsible portion will bulb and fold, and then the stem head will enter the region of reduced diameter, thereby radially expanding the thick-walled portion and forming an annular rib and deforming the folded collapsible portion so that it tends to move towards the pre-formed head, and then the breakneck will break.

2. A self-plugging blind rivet as claimed in claim 1, wherein the abutment face of the stem head is flat.

3. A self-plugging blind rivet as claimed in either of claims 1 or 2, wherein the stop groove is of part circular shape in cross-section.