US2818901A

US2818901A - Threaded insert with prongs extending from an end flange

Info

Publication number: US2818901A
Application number: US467924A
Authority: US
Inventors: Philip D Becker; Henrik S Johnsen
Original assignee: United Carr Fastener Corp
Current assignee: United Carr Fastener Corp
Priority date: 1954-11-10
Filing date: 1954-11-10
Publication date: 1958-01-07
Anticipated expiration: 1975-01-07

Description

1 j P. D. BECKER ET AL 2,818,901

THREADED INSERTEWITH PRONGS EXTENDING FROM AN END FLANGE Filed Nov. 10, 1954 2 Sheets-sheaf 1 \NvENToRs;

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Jan"; 1958 P. D. BECKER; ET AL 2,818,901

THREADED INSERT WITH PRONGS EXTENDING FROM AN END FLANGE Filed Nov. 10', 1954 Y 2 Sheets-Sheet 2 FacafZ F168.

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THREADED INSERT WITH PRONGS EXTENDING FROM AN END FLANGE Philip D. Becker, Hingham, and Henrik S. Johnsen, Medford, Mass., assignors, by mesne assignments, to United- Carr Fastener Corporation, Boston, Mass., a corporation of Delaware Application November 10, 1954, Serial No. 467,924

1 Claim. (Cl. 151-41.73)

This invention relates generally to fastening devices and has particular reference to a device for attachment to a panel to receive a cooperating fastener member.

111 the manufacture of certain types of flanged fastening devices, such as flanged nuts having a drawn threaded barrel, it has been desirable to form prongs from the flange to enable the device to be attached to a piece of wood or similar material.

Such devices are satisfactory for many applications, but in some cases it is desirable to provide prongs of greater length than has heretofore been practical, and in some cases it has been found that the prongs cause splitting of the wood during attachment.

It has heretofore been customary to provide longer prongs by increasing the dimensions of the flange from which the prongs are formed; however, this requires a wider strip of metal to form the larger flange and consequently increases the amount of scrap and the cost of the device. Longer prongs, so formed, also have the disadvantage that they tend to break at the junction with the flange, where the amount of working of the metal during forming is greatest and where the bending is greatest, which requires that the prongs be considerably widened at this point. However, prongs so widened have a greater tendency to cause splitting of the wood during attachment.

The object of the invention is to provide a flanged fastening device having prongs of suitable length formed from the flange in a manner requiring a minimum size of flange.

A further object of the invention is to provide a flanged fastening device having prongs formed from the flange in which means is provided to resist breaking of the prongs at the junction with the flange.

Other objects of the invention will, in part, be obvious, and will, in part, appear hereinafter.

In the drawing:

Fig. 1 is a top plan view of a fastening device embodying the features of the invention;

Fig. 2 is a view in side elevation of the fastener of Fig. 1;

Fig. 3 is a bottom plan view of the fastener of Fig. 1 assembled with a support panel;

Fig. 4 is a view in section taken on line 4--4 of Fig. 3;

Fig. 5 is a top plan view of a die used in forming the prongs from the flange;

Fig. 6 is a view in transverse section of a punch for use with the die of Fig. 5;

Fig. 7 is a view in transverse section of the assembled punch and die of Figs. 5 and 6 during the initial step of shearing the prongs from the flange;

Fig. 8 is a view in section taken on line 88 of Fig. 7;

Fig. 9 is a view in transverse section of the punch and die after the completion of the prong forming operation; and

Fig. 10 is a view in section taken on line 10-10 of Fig. 9.

eferring to the drawing, there is illustrated a fastenited States Patent 0 2,818,901 Patented Jan. 7, 1958 ing device 10 of the type commonly known as a flanged nut, which comprises a drawn barrel 12 having an mternal aperture 14 threaded to receive a bolt and an attachrng flange 18 disposed at one end of the barrel.

To permit attachment of the device 10 to a panel 20, a series of prongs 22 are formed in the outer periphery of the flange and are bent to extend substantially perpendicular thereto.

The prongs 22 are formed by a shear 24 which initiates at a point 25 spaced inwardly from the periphery and extends on an are generally circumferentially and progressing gradually radially outwardly. In the illustrated embodiment the are along which the shear extends has a radius R1 which is approximately the same as the radius R2 of the flange, and the center C1 of the arc is offset from the center C2 of the flange so that the arc' intersects the periphery of the flange in such a manner as to provide a tapered end portion terminating in a sharppoint 26.

To assist in the forming of the prongs in a manner to appear hereinafter and to prevent the tendency of the prongs to break at the junction with the base during at tachment, an embossed circular groove 27 is provided in the flange which passes through the initial points 25 at the inside edge of the prongs.

The preferred method of forming the prongs is best illustrated by reference to Figs. 5 through 10 in which is shown a die 28 and a punch 30 which have cooperating

shearing edges

32 and 34. The shearing edges 32 of the die progress circumferentially and inwardly and terminate at a rounded bending nose 36 which extends generally radially.

To form the prongs, the flanged nut is placed on the die, and the punch driven down onto the flange to force it through the die, shearing the flange along the cutting edges (see Figs. 7 and 8). As the punch is forced down further, the rounded nose 36 bends the prongs upwardly, and in doing so, tends to tear the metal at the base of the prong. Such tearing usually proceeds a distance about equal to the thickness of the metal of which the flange is formed. To insure that such tearing will proceed in the proper direction, that is circumferentially, and will not tend to extend across the base of the prong, the embossed circular groove 27 is provided in a suitable position to be at the inside edge of the junction of the prong with the base, so that the flange will tear along the line of weakness provided by the groove. As the punch is forced downwardly, the ends of the prongs, in turning upwardly, ride against the outer surface of the punch so that they are at least partially straightened. It has been found advantageous to stop the punch before the prongs are completely straightened, so that after completion of the operation, the prongs are curved slightly inwardly and I also slightly circumferentially (see Fig. 10). This structure has been found desirable for controlling the direction the prongs travel when being driven through a panel.

The method of forming of the prongs illustrated and described hereinbefore is particularly advantageous in cases where it is desired to secure a nut to a relatively thin piece of wood, without the barrel protruding therefrom. In such cases a relatively short barrel is required with long thin prongs for piercing completely through the wood without causing splitting.

As illustrated in Fig. 4, the fastener may be secured to a piece of wood 40 having an aperture 42 extending therethrough by driving the prongs through the wood and curling the ends over on the opposite side thereof, with the barrel 12 being disposed in the aperture 42. If desired, :1 prong positioning groove 44 may be provided about the aperture 42 to insure that the barrel is properly positioned to enter the aperture.

In the illustrated embodiment the groove extends completely around the tflange sin ce it is convenient to form the prongs in a secondary operation after the forming of the nut, without the necessity of orienting the nut in the die. However, it will be obvious that in some cases the ,embossedgroove need he formed in the flange only at the, egract positions needed. Although the illustrated embodiment utilizes three prongs, this is exemplary .only sinceother numbers may he used.

Sinc ce t in oth r obvious modifications .may he made in th devieewi hon sdepar ing from the scope ,of the in.- ntien, i intended tha all matter contained herein be interpreted in an illustrative and not in a limiting sense.

We claim:

A fastening de /ice for attachment to a panel -.to receive a cooperative fastener element comprising a center hrea ed as ne portion, an att ching flange disposed b u t e fas en por on and being substantiall perpend e la t th axis o the ta t n r po tion, a series of atta hin pr n ext nd ng substant ally p rp n i ular rom t e pl n pf t e flange sai p ong h being formed from the periphery of the flange by a shear extendinggenerally.circumferentially and progressing gradually radially outwardly therefrom to intersect the outer periphery of the flange and to form an arcuate portion, and a circumferential groove in said flange and disposed at the inside edge of the base of the prongs intersecting the ends of the shear whereby stresses occurring at the base of the prongs are directed circumferentially.

R fe ence Ci in he file of this P t nt UNITED STATES PATENTS 1,493,501 Rice May 13, 1924 2,102,558 Johnson Dec. 14, 1937 2,108,399 Allen .1 Feb. 15, 1938 2,284,081 Beggs May 26, 1942 FOREIGN PATENTS 11 6 ,35, 6 Great Britain June 11, 1918 449,422 Great Britain June 26, 1936