Expanding Nail

Abstract

An expanding nail which is split longitudinally from the tip end thereof to form two shank halves which squeeze together when the nail is driven through a member and expand to anchor the nail to the member. In a preferred embodiment, the shank halves have inner faces which slant inwardly from the tip end to bases of the shank halves to provide sufficient thickness of material in the shank at the bases of the shank halves to withstand flexure. The tips of the shank halves have outwardly slanting surfaces which act to squeeze the tip together when the nail is driven, and the shank halves have barbs spaced along the length thereof to receive material between the barbs so that the barbs catch on the material and hold the nail firmly in place. The nail is particularly suitable for attaching wallboard such as gypsum board to metal studs in building construction.

Description

BACKGROUND OF THE INVENTION

In building construction at the present time, it is becoming more and more common to use metal studs in the shape of channels in place of solid wooden studs, particularly in building interior walls in buildings. Screws or rivets are sometimes used to attach wallboard to the metal studs. The wallboard is usually a drywall known as gypsum board. It is believed that economies and a reduction in the time required to construct such walls could be achieved if automatic nailing equipment could be employed to attach wallboard to metal studs. Ordinary nails will not lock the wallboard to a metal stud, so a suitable type of self-clinching or self-fastening nail would be desirable.

It is an object of the present invention to provide a nail which can be driven through wallboard and a metal stud, and which will automatically anchor itself to the stud to hold the wallboard firmly in place.

Another object of the invention is to provide a nail with an expandable shank having barbs spaced along the length thereof in a manner to receive an edge of the stud through which the nail is driven between the barbs so that the barbs will catch on the stud edge and lock the nail in place.

Another object of the invention is to provide a nail with a split shank having tips which automatically squeeze together when the nail is driven to permit the nail to pass relatively easily through members such as wallboard and a metal stud.

A further object of the invention is to provide a nail with a split shank constructed such that the shank halves can squeeze together and spread apart without breaking the shank halves at their bases.

A further object of the invention is to provide an expanding nail with barbs on shank halves of the nail which barbs can pass relatively easily through material into which the nail is driven but which prevent the nail from being withdrawn from the material, thus allowing the nail to be driven through two members to fasten the members together and anchor the nail in place.

Other objects of this invention will appear from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

On the drawings:

FIG. 1 is an elevational view of an expanding nail in accordance with one embodiment of the invention;

FIG. 2 is an end view of the nail of FIG. 1 looking at the tips of the nail;

FIG. 3 is an end view of the nail looking at the head of the nail;

FIG. 4 is a fragmentary elevational view of the shank of the nail rotated 90.degree. relative to FIG. 1;

FIG. 5 is a view illustrating the manner in which the tips of the nail squeeze together as the nail is driven through wallboard and a metal stud;

FIG. 6 is a view similar to FIG. 5 but showing the nail in an expanded and anchored condition after it has been driven through the wallboard and metal stud;

FIG. 7 is an elevational view of a nail in accordance with another embodiment of the invention, this nail having a flat shank and also a flat head;

FIG. 8 is an end view of the nail of FIG. 7 looking at the tips of the nail;

FIG. 9 is another end view of the nail of FIG. 7 looking at the head of the nail; and

FIG. 10 is a plan view of the nail of FIG. 7.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring first to FIGS. 1 through 4, the nail 10 has a round, flat-topped head 12 with a curved rim 14 and a tapering neck 16 which is generally conical. The nail also has a shank generally designated 18, and the shank includes a continuous base portion 20 and two shank halves 22 and 24. The shank halves 22 and 24 have inner surfaces 26 and 28 which face each other across a recess 30, and the surfaces 26 and 28 extend from the tips 32 and 34 of the nail to base portions 36 and 38 of the shank halves located where the shank halves merge into the continuous base 20.

The purpose of the recess 30 is to allow the shank halves 22 and 24 to squeeze together, particularly at the tips 32 and 34, when the nail is driven through members such as wallboard and a metal stud. This means that the shank halves 22 and 24 must flex inwardly as the tip portions squeeze together and flex outwardly when the nail expands after it is driven through the members. This flexing of the shank halves imposes a strain on the base portions 36 and 38 which can cause the base portions to break if the material is too weak at this point. For this reason, it has been found to be very desirable to make the base portions 36 and 38 relatively thick to provide sufficient material and strength to withstand flexure. Therefore, the inner surfaces 26 and 28 of the shank halves are made to slant inwardly toward each other from the tips 32 and 34 to the base portions 36 and 38, thus defining a tapering recess which leaves sufficient thickness of material in the base portions 36 and 38 to withstand flexing. It can be seen that the recess 30 has been made very narrow at its inner end 40 so as to maximize the thickness of the material at 36 and 38.

The tips 32 and 34 of the shank halves have surfaces 42 and 44 leading from the relatively narrow edges of the shank and which are rounded and which taper or flare outwardly from the tips toward the head of the nail. These flared surfaces 42 and 44 act as cams against which the material into which the nail is driven thrusts to press the tips 32 and 34 together when the nail is driven through material, as will be described further. Tip 34 has lead-in side surfaces 46 and 48, and tip 32 also has lead-in side surfaces 50 and 52, and these lead-in side surfaces all lead from the respective opposite side surfaces of the shank and taper outwardly to form sharp points at the tips of the shank halves.

The shank halves 22 and 24 also have barbs 54 and 56 spaced along the length thereof, and these barbs serve to anchor the nail to material through which it is driven, as will be described further. The barbs 54 and 56 are spaced apart a substantial distance, and it may be noted that in the embodiment illustrated in FIGS. 1 through 4 there are longitudinal surfaces 58 and 60 at the roots of the barbs which separate the barbs from each other. The spacing of the barbs is sufficient to permit the edge of a steel stud to enter between any given pair of barbs after the nail has been driven through the stud so that the shank halves can expand outwardly and catch the edge of the stud between the barbs so that the nail cannot be easily withdrawn from the stud. It may also be seen in FIG. 1 that the barbs 54 and 56 have slanting surfaces which face the tips of the nail, and level surfaces which face the head of the nail. The slanting surfaces such as 62 allow the nail to pass through material through which it is driven relatively easily, and the level surfaces such as 64 cause the barbs to catch on the material so that it cannot be withdrawn easily. The angle of the slanting surfaces 62 preferably is in the range from 30.degree.-60.degree. , an angle of 45.degree. being shown.

The barbs 54 and 56 shown in FIg. 1 may be machined from a cylindrical shank, and the recess 30 may also be machined if desired. However, the barbs may be formed by other techniques such as cold heading if desired. In the nail as shown in FIGS. 1 and 4 the opposite side surfaces 66 and 68 at the lateral extremes of the recess 30 are formed flat, thus leaving shoulders at 70 and 72 in FIG. 4.

FIGS. 5 and 6 illustrate the manner in which the nail 10 may be driven through wallboard 74 (gypsum board) and a section 76 of a steel stud to anchor the wallboard to the stud. Stud section 76 may for example be 0.02-inch-thick steel which is relatively soft so that the nail can penetrate it. FIG. 5 shows the nail 10 as it is just entering the wallboard 74. It may be seen that the slanting surfaces 42 and 44 at the tips of the nail cause the tips to squeeze together forming a single point which allows the nail to pass easily through the members 74 and 76. As previously mentioned, the slanting surfaces 62 on the barbs 54 and 56 allow the barbs to pass easily through the members 74 and 76. FIG. 6 shows the nail 10 after the shank has passed through the wallboard 74 and the steel stud 76. The tip of the nail has pierced the steel stud 76, thus forming an opening with an edge which presses against the shank halves of the nail. The shank halves tend to expand or spread outwardly, or at least press outwardly if not actually expanding, so as to urge the shank halves against the edge 80 of the stud 76. The edge 80 enters in between two sets of barbs 54 and 56 so that the flat surfaces 64 on these barbs catch on the edge 80. This makes it very difficult to withdraw the nail 12 from members 74 and 76, and effectively anchors the wallboard 74 to the stud 76. The nail head 12 may be driven in to the point where it is flush with the top surface of the wallboard 74 or even recessed slightly without breaking the surface material of the wallboard.

The barbs 54 and 56 as shown in FIGS. 1 and 2 have curved edges, but it will be understood that the barbs are not restricted to this particular configuration. For example, they could be pointed if desired. In any event, it is believed to be desirable to have the slanting surfaces 62 and level surfaces 64 on the barbs. Surfaces 64 could slant in the same direction as surfaces 62 but at a different angle.

FIGS. 7 through 10 show another embodiment of the nail, and since it is very similar to the embodiment of FIGS. 1 through 4, the same reference numerals have been used for like parts. The main difference of the nail of FIGS. 7-10 as compared to that of FIGS. 1-4 is that in the nail of FIGS. 7-10 both the shank and the head are flat. This allows the nails to be stacked very closely together, for example in an automatic nailing apparatus, to conserve space in the apparatus. The nail of FIGS. 7 through 10 has the same tapered shank halves 22 and 24 with sharp point tips 32 and 34, a tapered recess 30 defined by inner surfaces 26 and 28 on the shank halves, tapered surfaces 42 and 44 flaring outwardly from the tips 32 and 34, and base portions 36 and 38 which merge into the continuous base 20 of the nail. The barbs 54 and 56 have slanting surfaces 62 and level surfaces 64 like those in the embodiment of FIGS. 1 to 4. As previously mentioned, the only significant difference is that the entire nail of FIGS. 7 through 10 is formed flat as by stamping, so it is conceptually very similar to cutting a section out of the middle of the nail of FIGS. 1 to 4.

It is apparent from the foregoing description that the invention provides a self-fastening nail which anchors itself to the material through which it is driven. The nail is particularly suitable for use in attaching wallboard to metal stud members in constructing buildings of various types, and the nail will anchor wallboard to a metal stud member very firmly. The split shank halves of the nail squeeze together as the nail is being driven to permit the nail to pass relatively easily through the material, and the shank halves are self-biased outwardly and have barbs which catch on the material, particularly a metal stud member, after the nail has been driven into that material.

Claims

Having thus described my invention, I claim:

1. A nail especially suitable for securing a relatively easily penetrable member such as wallboard to a relatively harder sheet metal support such as a stud, comprising:

a shank having relatively flat sides and opposite narrow edges, with a member-retaining head at one end of the shank and a sharp penetrating point at the extremity of an opposite end portion of the shank and of a hardness adapted to be readily driven into an imperforate sheet metal support to pierce a hole therein for the nail shank;

nail-anchoring barbs along an edge of the shank adapted to interlock with an edge defining the nail-pierced hole;

said shank edge and barbs being on a portion of the shank partially longitudinally separated and normally spread a limited distance from an adjacent portion of the shank and said portions being resiliently deflectable relative to one another to facilitate piercing of the sheet metal support during driving of the nail, followed by resilient biasing of the barbed portion toward said shank edge to assure thorough interlocking of a barb with the hole edge;

slanting cam surfaces on said opposite end portion leading from said narrow edges to said point; and

slanting lead-in surfaces on said opposite end portion leading from said flat sides to said point.

2. A nail according to claim 1, said shank portions comprising shank halves separated by a slot extending from a solid portion of the shank adjacent to said head to and through said tip, and the halves being movable toward one another during driving of the nail to provide a substantially single point toward which said cam and lead-in surfaces taper to facilitate piercing of the sheet metal support.

3. A nail according to claim 1, in combination with the penetrable member lying against a sheet metal support such as a stud, the nail being driven into the member and support to an extent wherein engagement of the barb with the hole edge holds the head countersunk within an outer face surface of the member.

4. A nail especially suitable for securing a relatively easily penetrable member such as wallboard to a relatively harder sheet metal support such as a stud, comprising:

a shank having relatively flat sides and opposite narrow edges, with a member-retaining head at one end of the shank and a sharp penetrating point at the extremity of an opposite end portion of the shank and of a hardness adapted to be readily driven into an imperforate sheet metal support to pierce a hole therein for the nail shank;

nail-anchoring barbs along an edge of the shank adapted to interlock with an edge defining the nail-pierced hole;

said shank edge and barbs being on a portion of the shank partially longitudinally separated and normally spread a limited distance from an adjacent portion of the shank and said portions being resiliently deflectable relative to one another to facilitate piercing of the sheet metal support during driving of the nail, followed by resilient biasing of the barbed portion toward said shank edge to assure thorough interlocking of a barb with the hole edge;

slanting cam surfaces on said opposite end portion leading from said narrow edges to said point;

slanting lead-in surfaces on said opposite end portion leading from said flat sides to said point; and

a tapered neck of substantial length connecting said shank with said head and joining the head adjacent to its rim.

5. A nail according to claim 4, in which said head has a circular perimeter defined by said rim and said neck is frustoconical.

6. A nail according to claim 4, wherein said head is flat-sided in alignment with said relatively flat sides of the shank.