GB1604727A

GB1604727A - Blind fasteners

Info

Publication number: GB1604727A
Application number: GB23103/78A
Authority: GB
Original assignee: Huck Manufacturing Co
Current assignee: Huck Manufacturing Co
Priority date: 1977-07-19
Filing date: 1978-05-26
Publication date: 1981-12-16
Also published as: JPS5439757A; FR2398210A1; CA1096667A; IL54963A; BR7804559A; FR2398210B1; JPS62369B2; DE2829984C2; NL7807284A; SE439344B; BE868926A; SE7807009L; IL54963A0; DE2829984A1

Description

(54) BLIND FASTENERS (71) We, HUCK MANUFACTURING COM- PANY a Corporation organized and existing under the laws of the State of Michigan, United States of America, of 2500 Bellevue Avenue, Detroit 7, State of Michigan, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention deals with a blind fastener of a selected metal for joining together a plurality of work pieces.

One of the main difficulties Th blind fasteners has been in providing a construction which would assure uniform preload values for a variety of grips corresponding to the total thickness of the work pieces to be joined. Illustrative of prior attempts are disclosed in U.S. Patents Nos. 3,702,088; 3,148,578; 3,288,016 and 3,880,042.

According to the present invention, a blind fastener is provided of a selected metal for joining together a plurality of work pieces over a wide range of material thicknesses comprising a hollow tubular sleeve having a preformed head at one end and an open tubular extension at the other end, a solid pin including a shank disposed within said tubular sleeve and having pull means formed thereon projecting out of the preformed head on the sleeve and having a solid blind head-forming portion projecting out of said other end of said sleeve, said blind head-forming portion comprising a plurality of spaced ribs forming grooves therebetween, said ribs having a greater outer diameter than the internal diameter of the tubular extension, said internal diameter permitting the ribs to be collapsed within said sleeve for a portion of the sleeve contained within the workpieces adjacent that surface of the workpiece most proximate to the said other end of the sleeve.

In the preferred form the ribs are formed by spaced annular grooves. An alternate way would be the formation of such ribs as a spiral thread.

Depending upon the grip or material thickness with which the fastener is used, the ribs will progressively engage the end of the sleeve, form the blind head, and collapse or progressively fold back as the head is formed. At the end of the stroke, depending on the grip, pull pressure builds up to break the pin at the breakneck to complete setting of the fastener.

In the embodiment illustrated the pin and sleeve are preferably locked together as disclosed in the above U.S. Patent 3,288,016.

Other known ways of providing the interlock may be used.

The invention will now be described with reference to specific embodiments and illustrated in the accompanying drawings wherein: Figure 1 is a side elevational view of a fastener with parts sectioned and parts in elevation and in assembled relation with a pair of workpieces to be fastened together at nominal grip and with the fastener depicted prior to being set; Figure 2 is a view similar to Figure 1 depicting the fasteners at an early stage of its being set; Figure 3 is a view similar to Figure 2 at a further stage; Figure 4 is a view similar to Figures 2 and 3 at the final set stage, with the pin tail broken off and with the pin and sleeve interlocked; and Figure 5 is a view similar to Figure 4 with the fastener finally set in workpieces of maximum thickness or maximum grip.

Referring to Figures 1 to 4, a fastener 10 is shown in assembled relationship with a pair of workpieces 12 and 14 to be joined together. The fastener 10 comprises a tubular sleeve 16 with a central bore 18 and solid pin 20 extending therethrough.

The sleeve 16 has a frusto-conically shaped head 22 at its forward or outside end which mates with a countersunk bore 24 in the outer face of the workpiece 14. The sleeve 16 has a cylindrical body portion 26 which extends rearwardly through and sub stantially beyond opening 28 in rear or inner workpiece 12.

The bore 18 terminates adjacent the head 22 in an annular shoulder 30 which provides material for interlocking the pin 20 and the sleeve 16 and also provides a positive stop for limiting the movement of the pin 20 relative to the sleeve 16 as disclosed in the aforementioned U.S. Patent 3,288,016.

The pin 20 as assembled to the sleeve has a head end generally indicated at 32, a shank portion 34, a lock groove 36, a breakneck groove 38, and a pull portion 40 formed of annular pull grooves in the usual way.

The present invention lies in the construction of the head end 32 of the pin 20, its arrangement with respect to the inner end of the sleeve and its function in forming the blind head for the accommodation of different grips.

The head end portion 32 comprises a plurality of annular ribs 42, 43, 44 and 45 and terminating in an end rib 46. Such ribs are formed by spaced annular grooves 48 the root diameters of which are less than the diameter of the shank portion 34. The ribs are also preferably shaped to have a pyramidal cross-sectional configuration tapering inwardly to have a base portion of greatest strength. This permits the controlled and progressive bending of the ribs as the fastener is set.

By controlling the depth, or root diameters, of the grooves 48 and/or the transverse width or configurations of the grooves, the cross-sectional configuration of the ribs may be likewise varied to vary the resistance to deflection or bending of such ribs. Thus, sleeve expansion or head formation may be varied for a desired design as well as load resistance at any portion of the installation cycle.

The rib 42 is stronger than ribs 43, 44 and 45 because the diameter of shank 34 is greater than the root diameter of adjacent groove 48. In the embodiment illustrated, ribs 43, 44 and 45 have uniform resistance to bending. But, variation in such bending resistance could be accomplished by varying the root diameters of grooves 48. The end rib 46 preferably has the greatest width dimension so that it is the strongest and not bendable at the end of the setting stroke.

Referring to Figure 2, the blind head has been formed and the first rib 42 collapsed or folded back. In Figure 3, at a further step in the setting cycle, the pin 10 has moved further into the sleeve and ribs 42 and 43 folded back or collapsed. In Figure 4, the pin 10 has been moved to its complete set position, the interlock adjacent shoulder 30 has occurred, and the pin broken at the breakneck 38. For this grip, ribs 42 and 43 have folded back and rib 44 is beginning to fold back.

Referring to Figure 5, workpieces 13 and 15, corresponding to members 12 and 14, are thicker and may be considered as illustrative of maximum grip. Thus, when finally set, ribs 42, 43, 44 and 45 have all collapsed backwardly.

WHAT WE CLAIM IS: 1. A blind fastener of a selected metal for joining together a plurality of work pieces over a wide range of material thicknesses comprising a hollow tubular sleeve having a preformed head at one end and an open tubular extension at the other end, a solid pin including a shank disposed within said tubular sleeve and having pull means formed thereon projecting out of the preformed head on the sleeve and having a solid blind head-forming portion projecting out of said other end of said sleeve, said blind headforming portion comprising a plurality of spaced ribs forming grooves therebetween, said ribs having a greater outer diameter than the internal diameter of the tubular extension, said internal diameter permitting the ribs to be collapsed within said sleeve for a portion of the sleeve contained within the workpieces adjacent that surface of the workpiece most proximate to the said other end of the sleeve.

2. A blind fastener according to claim 1, wherein the number of ribs which fold back is selected on the basis of the variation in the material thickness of the plurality of workpieces desired so as to be proportional to said thickness.

3. A blind fastener according to claim I or 2, wherein grooves between the ribs are of a smaller root diameter than the diameter of the pin shank.

4. A blind fastener according to any one of the preceding claims, wherein the last following rib of the head forming portion is of the greatest strength and the first leading rib is of a strength more resistant to deflection than the remaining ribs intermediate the last following rib and the first leading rib.

5. A blind fastener according to claim 4, wherein the remaining intermediate ribs are of uniform resistance to deflection.

6. A blind fastener for joining together a plurality of work pieces over a wide range of material thicknesses substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

22 in an annular shoulder 30 which provides material for interlocking the pin 20 and the sleeve 16 and also provides a positive stop for limiting the movement of the pin 20 relative to the sleeve 16 as disclosed in the aforementioned U.S. Patent 3,288,016.

The pin 20 as assembled to the sleeve has a head end generally indicated at 32, a shank portion 34, a lock groove 36, a breakneck groove 38, and a pull portion 40 formed of annular pull grooves in the usual way.

The present invention lies in the construction of the head end 32 of the pin 20, its arrangement with respect to the inner end of the sleeve and its function in forming the blind head for the accommodation of different grips.

The head end portion 32 comprises a plurality of annular ribs 42, 43, 44 and 45 and terminating in an end rib 46. Such ribs are formed by spaced annular grooves 48 the root diameters of which are less than the diameter of the shank portion 34. The ribs are also preferably shaped to have a pyramidal cross-sectional configuration tapering inwardly to have a base portion of greatest strength. This permits the controlled and progressive bending of the ribs as the fastener is set.

By controlling the depth, or root diameters, of the grooves 48 and/or the transverse width or configurations of the grooves, the cross-sectional configuration of the ribs may be likewise varied to vary the resistance to deflection or bending of such ribs. Thus, sleeve expansion or head formation may be varied for a desired design as well as load resistance at any portion of the installation cycle.

The rib 42 is stronger than ribs 43, 44 and 45 because the diameter of shank 34 is greater than the root diameter of adjacent groove 48. In the embodiment illustrated, ribs 43, 44 and 45 have uniform resistance to bending. But, variation in such bending resistance could be accomplished by varying the root diameters of grooves 48. The end rib 46 preferably has the greatest width dimension so that it is the strongest and not bendable at the end of the setting stroke.

Referring to Figure 2, the blind head has been formed and the first rib 42 collapsed or folded back. In Figure 3, at a further step in the setting cycle, the pin 10 has moved further into the sleeve and ribs 42 and 43 folded back or collapsed. In Figure 4, the pin 10 has been moved to its complete set position, the interlock adjacent shoulder 30 has occurred, and the pin broken at the breakneck 38. For this grip, ribs 42 and 43 have folded back and rib 44 is beginning to fold back.

Referring to Figure 5, workpieces 13 and 15, corresponding to members 12 and 14, are thicker and may be considered as illustrative of maximum grip. Thus, when finally set, ribs 42, 43, 44 and 45 have all collapsed backwardly.

WHAT WE CLAIM IS: 1. A blind fastener of a selected metal for joining together a plurality of work pieces over a wide range of material thicknesses comprising a hollow tubular sleeve having a preformed head at one end and an open tubular extension at the other end, a solid pin including a shank disposed within said tubular sleeve and having pull means formed thereon projecting out of the preformed head on the sleeve and having a solid blind head-forming portion projecting out of said other end of said sleeve, said blind headforming portion comprising a plurality of spaced ribs forming grooves therebetween, said ribs having a greater outer diameter than the internal diameter of the tubular extension, said internal diameter permitting the ribs to be collapsed within said sleeve for a portion of the sleeve contained within the workpieces adjacent that surface of the workpiece most proximate to the said other end of the sleeve.
2. A blind fastener according to claim 1, wherein the number of ribs which fold back is selected on the basis of the variation in the material thickness of the plurality of workpieces desired so as to be proportional to said thickness.
3. A blind fastener according to claim I or 2, wherein grooves between the ribs are of a smaller root diameter than the diameter of the pin shank.
4. A blind fastener according to any one of the preceding claims, wherein the last following rib of the head forming portion is of the greatest strength and the first leading rib is of a strength more resistant to deflection than the remaining ribs intermediate the last following rib and the first leading rib.
5. A blind fastener according to claim 4, wherein the remaining intermediate ribs are of uniform resistance to deflection.
6. A blind fastener for joining together a plurality of work pieces over a wide range of material thicknesses substantially as herein described with reference to the accompanying drawings.