IN A POWERED FASTF.NFR DRIVING TOOL

BACKGROUND OF THE INVENTION

5

1. Field of the Invention

The present invention relates generally to nails adapted to formed into a strip for

use in powered nailing tools, and in particular, to an improved round head nail

10 capable of being collated in a compact fastener strip.

2. Description of the Prior Art

15 The use of pneumatic nail driving tools have become very popular where it is

necessary to fasten pieces of wood together. Workers in industries such as house

construction regularly use these tools to increase productivity as well as improve

the appearance and quality of their work.

-0 Pneumatically powered nail driving tools typically use collated strips of nails in

which the shanks of the nails are adhered in a parallel relationship at an angle,

such that the lead nail can be individually separated from the strip and driven into

a workpiece. It is important that the shanks of adjacent nails be positioned as

close together as possible in order to allow the optimum number of nails in the

strip, so that the nailing tool can be used without requiring frequent reloading.

One method commonly used to increase the number of nails in a strip is to employ

a nail head which is shaped such that it allows the shanks of adjacent nails to

contact each other. These types of nails, which are taught in U.S. Patent Nos.

2,940,081 and 3,481,526, are often referred to as clipped, or D-headed, nails.

Although nails of this construction are very adequate for securely holding

workpieces, it is sometimes a perception that the holding power of such nails is

inadequate, as the nail does not have a complete circular head.

Several attempts have been made to develop a collated nail strip which contains

nails having full round heads. U.S. Patent No. 3,358,822, which issued December

19, 1967 to R.F. O'Connor, teaches a nail strip which uses eccentric full round

headed nails. U.S. Patent No. 4,234,991, which issued November 25, 1980 to W.

Lange, teaches a nail strip in which the full round head of each nail is inclined

approximately 15 degrees to the plane normal to the axis of the nail shank. U.S.

Patent No. 5,056, 976, which issued October 15, 1991 to Sygnator et al., teaches a

nail having a head with two planar surfaces where the circumferential edge

conforms to a complete circle. U.S. Patent No. 5,395,197, which issued on

March 7, 1995, teaches a nail having a non-circular head defined by at least two

dissimilar convex curved shapes. U.S. Patent No. 5,482,419, which issued on

January 9, 1996, to H. Leistner, teaches a nail with an offset reinforced full head

with reinforcing ridges along each side of the nail shank.

Although these prior art references all teach full round headed nails capable of

being collated into a nail strip, each has different deficiencies in the complexity of

its design or manufacturability.

SUMMARY OF TFTE INVENTION

It is therefore an object of the present invention to provide a nail which can be

collated in a compact strip without using a clipped head design.

It is a further object of the present invention to provide a nail with an essentially

full round head which is easily manufactured and provides excellent holding

power within a workpiece.

These and other objects of the present invention are accomplished by a novel nail

design having a cylindrical shank and a head with a generally circular shape

which is truncated by a straight edge which forms a chord to the circular shape

such that the total surface area of the head is between 85 and 95 percent of the

total area contained in a complete circular head of the same size. The shank of

the nail is positioned tangent to the straight edge of the head.

BRIEF DESCRIPTION OF THF. DRAWINGS

FIG. 1 is a side elevational view of the nail of the present invention;

FIG. 2 is a frontal view of the nail of FIG. 1;

FIG. 3 is a top view of the nail of FIG. 1;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1 ;

FIG. 5 is an enlarged view of the head of the nail of FIG. 1; and

FIG. 6 is a side elevational view of a strip of nails each formed according to the present

invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring more particularly to the drawings, there is shown therein a nail, generally

indicated at 10, which embodies the principles of the present invention. Nail 10 has a generally

cylindrical shank 12 and an offset head 14 formed perpendicular to and integral with shank 12.

The opposite end of shank 12 from head 14 terminates in a workpiece penetrating point 16.

Point 16 may be configured from a series ef faces 16a, or may be v-shaped in cross-sectional

configuration, conically shaped, or any other configuration which is well known in the art.

Shank 12 may also contain a series of parallel gripper die marks 18 which may be formed onto

shank 12 during the manufacturing process.

Head 14 has an upper surface 20, a circumferential edge 22. and a lower surface 24.

Head 14 is of a substantially circular configuration which terminates in a flat planar edge 26.

Edge 26 forms a chord which intersects the circle which is formed by the configuration of upper

surface 20 of head 14 as can be clearly seen in FIG. 3. The position of edge 26 is selected such

that the surface area of upper surface 20 is between 85 to 95 percent of the total surface area of a

completely circular nail head of the same size. Ideally, the surface area of upper surface 20 is

approximately 90 percent of a full circular head of the same size.

Head 14 is affixed to shank 12 of nail 10 such that edge 26 is tangential to the periphery

of the cylindrical shank, as can be clearly seen in FIG. 4. This corifiguration allows nails 10 to

be collated with the adjacent shanks contacting one another, thus allowing a nail strip to be

formed containing the maximum number of nails, if possible.

Edge 22 may be a fiat edge, or it can be a curved surface, as can be clearly seen in FIG. 5.

Lower surface 24 of head 14 contains a notched poπion 28 on each side of shank 12 extending

outwardly from edge 26 along the periphery of head 14. Notched portion 28 extends around

shank 12 of nail 10 such that it surrounds approximately 180 degrees of shank 12 on the side

which is tansent to edse 26.

A reinforcing support or fillet 30 is provided on lower surface 24 of head 14 and contacts

cylindrical shank 12 of nail 10 about its periphery. Fillet 30, which is created during the

formation of nail 10, consists of a first support 32 and a second support 34. First support 32

contacts shank 12 about the section of shank 12 away from edge 26, while second support 34

extends from the point of tangency of shank 12 with edge 26 away from edge 26 in both

directions until it contacts first support 32, as can be best seen in FIG.4.

FIG. 6 shows a nail strip 35 made up of a plurality of nails manufactured according to

this invention. Referring now to FIG. 6, nails 10 are arranged such that shank 12 of each nail

contacts the shank of both the preceding nail and also the following nail. Points 16 of the nails

are arranged such that a plane through points 16 forms an angle of between approximately 25 to

40 degrees with the plane of shank 12. Ideally, the strip angle is between 30 and 35 degrees.

The fasteners of strip 35 are held in position by a suitable collating means 36. Collation means

36 may be an adhesive tape, a wire which is mechanically fastened to each nail 10, or any other

method which is known in the art. Strip 35 can be used in a conventional powered nail driving

tool which has a magazine using the same angle at which the nails are collated.

While the invention has been shown and described in terms of a preferred embodiment,

it will be understood that this invention is not limited to this particular embodiment, and that

many changes and modifications may be made without departing from the true spirit and scope

of the invention as defined in the appended claims.