US3675817A

US3675817A - Fastening device

Info

Publication number: US3675817A
Application number: US116372A
Authority: US
Inventors: Donald Lake; Badger Perrin; Frederick J Nolan
Original assignee: TRW Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1971-02-18
Filing date: 1971-02-18
Publication date: 1972-07-11
Anticipated expiration: 1989-07-11
Also published as: GB1344772A; CA951551A

Abstract

A fastening device known as a tack attached burr. A low profile shell has a tack receiving and retaining vise seated therein. The vise includes a hollow shank having an upper end bearing against the undersurface of the crest of the shell and an opposite outwardly flared end which merges into a peripheral flange. The flange is turned back toward the upper end of the shank and the crest of the shell. The shell is crimped over the vise and has an inwardly turned rim at its end opposite the crest. The rim underlies a substantial area of the flange on the vise and extends downwardly away from the shell crest and terminates in a free circular edge defining a tack receiving opening in axial communication with the shank of the vise.

Description

United States Patent Lake et al. July 11, I972 [54] FASTENING DEVICE Primary Examiner-Remard A. Gelak [72] 3? j s z f g' z gs Anomey-Philip E. Parker, James R. OConnor, Hall &

i z gh e c o ater l-loughton and Gordon Needleman [73] Assignee: TRW Inc., Cleveland, Ohio [57] CT [22] Filed: Feb. 18, 1971 A fastening device known as a tack attached burr. A low profile shell has a tack receiving and retaining vise seated [21] 1 16,372 therein. The vise includes a hollow shank having an upper end bearing against the undersurface of the crest of the shell and 52 us. Cl ..24 9s 85 37 JutwardlY flaed end Whih merges E 1 4 peripheral flange. The flange is turned back toward the upper [58] Field of Search ..24/95 90 A 90 R 90 PR- end Shank and The shell is mind 85/37 over the vise and has an inwardly turned rim at its end opposite the crest. The rim underlies a substantial area of the flange on the vise and extends downwardly away from the [56] References Cmd shell crest and terminates in a free circular edge defining a UNITED STATES PATENTS tack receiving opening in axial communication with the shank of the vise. 548,143 10/1895 Shipley.... ..24/95 563,460 7/1896 Dowse ..24/95 5 Claims, 5 Drawing Figures P'A'TENTEDJUL 11 I972 3.675.817

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IO 8' 5o 2 22 24 26 34 I2 "52 36 I Fl G. 5

' INVENTORS DONALD LAK BADGER PER FREDERICK J. NOLAN ATTORNEY FASTENING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a tack attached fastener which is generally known as a burr. Such fasteners would properly be found in U.S. Patent Office Class 24, Subclass 94, entitled Buttons and Fasteners Deflecting Prong or Rivet."

2. Description of the Prior Art The prior art includes a number of tack attached buttons and burrs. In most cases a separate anvil seated within a capped button or burr shell is utilized to effect axial and/or radial deformation of the leading end of the tack shank. In many instances the prior art devices require extensive skewing and/or coiling of the tack shank to achieve a secure attachment. In a few instances the crest of a dome-shaped burr or button acts as the anvil for tack shank deformation. However, the last mentioned devices usually employ tack retainers or vises which are relatively expensive in that specialized tooling and costly secondary operations are required for their manufacture. The prior art devices are also generally characterized by what is best termed a high profile construction that has proved acceptable for buttons and burrs attached to Work clothes, rugged footwear and similar articles wherein styling and overall attractiveness are of secondary importance to durability. However, in the more fashion and style conscious high quality apparel and leather goods trade, the need for a low profile burr construction which retains the requisite durability and strength in attachment of the earlier designs has long existed. The principal objective of the presently disclosed burr is to satisfy that need.

SUMMARY OF THE INVENTION The illustrated embodiment of a burr comprises a shallow, low profile shell having a dome defining a closed crest at one end and an inwardly turned rim at its opposite end. The rim merges with the dome in a relatively sharp bend and terminates in a free edge defining an opening providing an entrance to the interior of the shell. A vise secured within the shell includes a hollow shank having inverted funnel-like sec tions which merge intermediate the length of the shank in a necked section of greatly reduced diameter. The upper end of the shank bears against the undersurface of the shell crest and in cooperation therewith defines a tack shank clinching chamber. The opposite end of the shank opens into communication with the shell opening defined by the rim and merges into a peripheral flange which extends radially outwardly of the shank and longitudinally back toward the upper end of the shank and the crest of the shell. The flange terminates in an outer edge which is braced against the inner wall of the shell adjacent the bend. The rim underlies a substantial area of the vise flange and extends downwardly in a direction away from the shell crest to its opening defining edge.

DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of two fragmentary swatches of leather secured in overlapping relationship by a burr and tack attachment;

FIG. 2 is a perspective view of the burr and tack on opposite DESCRIPTION OF THE PREFERRED EMBODIMENT As best depicted in FIGS. 4 and 5 of the drawing the burr 2 comprises two major components, to wit a shell 4 and a vise 6, the latter being secured within the shell.

The shell 4 includes a dome-shaped upper portion 8 lying on a radius selected to provide a very low profile configuration. The dome 8 defines a crest 10 at its upper end and merges at a relatively sharp bend 12 into an inwardly turned rim 14 at its end opposite the crest. The bend 12 lies on a radius which is substantially shorter than that of the dome 8. The rim 14 terminates in a free, generally circular edge 16 which defines an opening 18 providing an entrance to the shell. The extreme lower end of the rim is bevelled at 20 to provide a smooth facing surface, the purpose of which will be further described hereinafter.

Vise 6 has a hollow shank including what might best be described as an upper funnel-like section 22 and a lower, inverted funnel-like section 24, which sections merge intermediate the length of the shank in a necked section 26 of reduced diameter. The shank sections define a tack receiving passageway 28 which is in axial communication with the opening 18 of the shell. The upper end of the shank section 22 is butted against the internal surface of the crest 10 of the shell and cooperates therewith to define a tack shank clinching and retaining chamber 30. The vise shank might further be properly described as having a longitudinal concavo-convex configuration as is best seen in the cross sectional views of FIGS. 4 and 5.

Adjacent its lower end the shank section 24 merges into a peripheral flange 32 which extends radially outwardly from the shank and is turned back toward the shank section 22 and the crest of the shell. The outer end 34 of the flange bracingly engages the internal surface of the shell at the bend l2 and the extreme upper edge of the flange lies generally coplanar with the necked section 26 of the shank. The rim 14 of the shell is crimped or coiled around the flange 32 and underlies a substantial area thereof but, as best seen in FIG. 4, the terminal edge 16 of the rim is spaced considerably from the entrance to the passageway 28 of the vise shank.

The component parts heretofore described are formed from sheet metal, for example carbon steel, and are usually copper coated for decorative purposes. Ideally, the shell is burnished or otherwise treated to remove sharp edges, particularly at the inner end and lower face of the rim 12. The parts are generally of cylindriforrn configuration and are symmetrical about the longitudinal axis of the vise shank.

A burr according to the invention may be attached to leather goods, apparel, upholstery, etc., purely for decorative purposes. It may also function in conjunction with the tack 36 as a fastener combination whereby sections of a garment are secured or a leather strap end is secured in a fold, or a strap is fastened to an article such as a ladys handbag or in any similar assembly. The only real limitation on its effective utilization as a fastener is that the material must be capable of being pierced by the tack. The attachment may be carried out with hand tools or automatic machinery.

A typical tack 36 used with the burr includes a head 38, a shank having a sharp point 42 and a decorative cap 44 which is curled over the head 38.

The burr 2 and tack 36 are fastened together in a typical installation by piercing the sections of material to be secured, as depicted in the drawings the

leather swatches

46,48, with tack point 42 and shank 40, inserting the shank 40 into the passageway 28 in the vise 6, and then clinching the leading end of the tack in the chamber 30. During the clinching operation the shell 4 is supported by an appropriate die and the end of the tack is forced against the undersurface of the crest 10 of the shell whereby it is deformed both axially and radially into an enlarged head 50. The enlarged head 50 engages both the undersurface of the crest 10 of the shell and the internal wall of the upper shank section 22 of the vise and is in effect trapped in the chamber 30 above the necked portion 26 of the vise shank. Thus the

swatches

46,48 are bound tightly together as depicted in FIG. 5, the smooth bevelled surface 20 of the shell rests against the outer surface of the swatch 48 whereby potential tearing or marring of the leather material is substantially reduced, the deformed end of the tack forms an additional brace to inhibit potential crushing of the burr shell, for example, during a cleaning or pressing operation, and the flange 32 of the vise is placed under a radially directed force which further tensions the outer edge 34 thereof against the wall of the shell at the bend 12.

It will be observed that in the assembly the shank of the vise tightly, circumferentially grips in excess of one-half the length of the shank 40 of the tack disposed within the confines of the burr. Thus a secure attachment which will effectively resist accidental separation is realized. It will further be observed that the inverted funnel-like configuration of the lower section 24 of the vise shank is particularly adapted to guide the tack shank into the vise during the assembly operation, and that the spacing of the terminal edge 16 of the shell rim from the entrance to the vise shank effectively precludes premature bending or skewing of the tacking shank by reason of its accidentally engaging the lower edge of the shell during assembly. While the objective of providing an efficient burr attachment having a very low profile has been realized, it is significant to note that thedisclosed shell configuration results in a slight gap 52 between the confronting surface of the swatch 48 and the bend 12 of the shell in the assembly (see FIG. 5 in particular). Thus the burr is adapted to function as a button over which a perforated strap, for example, may be passed or around which twine or string may be wound in the manner of a pouch or envelope fastener.

The foregoing detailed description of the invention is to be interpreted in an illustrative as opposed to a limiting sense in that it is contemplated that the disclosed preferred embodiment might well be altered or modified without departing from the spirit of the invention, the scope of which is best defined by the claims which follow.

We claim: 7

1. A burr which is adapted to be secured to a workpiece by a fastening means such as a tack, comprising a low profile shell, said shell having a domelike portion defining a closed crest at one end of said shell and an inwardly turned rim at its opposite end, said rim merging with said domelike portion at a bend, said rim extending inwardly from said bend and terminating in a free edge, said free edge defining an opening providing ingress to the interior of said shell, and a vise secured within said shell, said vise including a shank defining a tack receiving passage, said shank having a first end portion proximate the said rim of said shell opening into axial communication with the said opening in said shell and a second end portion bearing against the undersurface of the crest of said domelike portion of said shell, said second end portion cooperating with the undersurface of said crest to define a tack shank clinching chamber, said first end portion of said shank merging into a peripheral flange extending laterally outwardly from said shank and longitudinally back toward said second end portion of said shank and said domelike portion of said shell, said flange terminating in a free edge lying substantially above the said opening in said shell and bracingly engaging the internal wall of said shell adjacent the said bend therein.

2. A burr according to claim 1 wherein the radius of said bend in said shell is substantially shorter than the radius of the said domelike portion of said shell.

3. A burr according to claim 1 wherein said rim extends downwardly as well as inwardly from said bend and said free edge of said rim is directed away from the said crest of said shell.

4. A burr according to claim 1 wherein both said first and second end portions of said shank are flared outwardly in a funnel-like configuration with respect to the longitudinal axis of said shank, and said end portions merge in a necked portion of reduced width intermediate the length of said shank.

5. A burr according to claim 1 wherein the said rim of said shell underlies a substantial portion of the flange on said vise and the free edge of said rim terminates at points spaced substantially, radially outwardly from the said first end portion of said shank to provide for unimpeded entrance of a tack into said tack receiving passage in said xise

Claims

5. A burr according to claim 1 wherein the said rim of said shell underlies a substantial portion of the flange on said vise and the free edge of said rim terminates at points spaced substantially, radially outwardly from the said first end portion of said shank to provide for unimpeded entrance of a tack into said tack receiving passage in said vise.