Fastener tool

A fastener tool is provided for attaching a protective strip to a corner formed by two intersecting walls. The fastener tool includes a handle for being gripped by a user. First and second fastener guns are supported by the handle at a predetermined angle in relation to each other and to the intersecting walls. The first and second fastener guns drive respective fasteners into the protective strip and intersecting walls thereby attaching the strip to the corner. A trigger mechanism is connected to the handle for actuating the first and second fastener guns.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION 
This invention relates to a fastener tool. The invention is particularly 
useful by dry wallers for applying a corner bead to a corner formed by two 
intersecting walls. The corner bead is a relatively narrow strip of metal 
or plastic formed at a right angle, and attached to the sheet rock of the 
intersecting walls before plastering. The corner bead defines the outside 
edge of the wall corner, and serves to protect the edge from chipping and 
cracking. The corner bead is typically attached to the wall corner by 
fasteners, such as nails or staples. 
Dry wallers commonly use a standard compressed-air powered staple gun or 
nail gun to drive the fasteners into each outer side of the corner bead 
and intersecting walls. To properly attach the corner bead, the user 
drives one fastener into an outer side of the corner bead and first wall, 
and then shifts the fastener gun to the other wall to drive a second 
fastener into the opposite outer side of the corner bead and second wall. 
This procedure is repeated throughout the entire length of the corner bead 
until a generally equal number of fasteners are applied to each wall and 
each outer side of the corner bead. Use of the standard, prior art 
fastener gun in this manner is time consuming and inefficient. Mistakes 
and misfiring frequently occur in an attempt to speed up this process. 
The present invention addresses these and other limitations of prior art 
fastener guns by providing a tool which includes two fastener guns mounted 
perpendicular to each other for simultaneously driving fasteners into each 
outer side of the corner bead and intersecting walls without shifting the 
tool between the adjacent walls. By moving the invention vertically along 
the length of the corner bead and actuating a trigger mechanism, the user 
can properly attach the corner bead in a fraction of the time required 
using conventional tools. Moreover, since the invention does not require 
shifting between adjacent walls, the user expends much less energy, and is 
less likely to make mistakes or misfires. 
SUMMARY OF THE INVENTION 
Therefore, it is an object of the invention to provide a fastener tool for 
applying a protective strip to a corner formed by two intersecting walls. 
It is another object of the invention to provide a fastener tool which 
properly attaches the protective strip to the wall corner with a single 
vertical pass of the tool along the wall corner. 
It is another object of the invention to provide a fastener tool which 
properly attaches the protective strip to the wall corner without shifting 
the tool between the adjacent, intersecting walls. 
It is another object of the invention to provide a fastener tool which 
reduces user mistakes and misfiring of fasteners as the protective strip 
is applied to the wall corner. 
It is another object of the invention to provide a fastener tool for 
attaching the protecting strip in a more efficient manner relative to that 
of conventional tools. 
These and other objects of the present invention are achieved in the 
preferred embodiments disclosed below by providing a fastener tool for 
attaching a protective strip to a corner formed by two intersecting walls. 
The fastener tool includes a handle for being gripped by a user. First and 
second fastener driver means are supported by the handle at a 
predetermined angle in relation to each other and to the intersecting 
walls. The first and second fastener driver means drive respective 
fasteners into the protective strip and intersecting walls thereby 
attaching the strip to the corner. Trigger means is connected to the 
handle for actuating the first and second fastener driver means. 
According to one preferred embodiment of the invention, the first and 
second fastener driver means are disposed substantially perpendicular to 
each other for inserting fasteners into the protective strip and 
intersecting walls. 
According to another preferred embodiment of the invention, a mounting shoe 
is connected to the handle and the first and second fastener driver means 
for engaging the protective strip and holding the protective strip against 
the corner as the fasteners are applied to the protective strip and 
intersecting walls. 
According to yet another preferred embodiment of the invention, the 
mounting shoe is an angled segment of substantially L-shaped 
cross-section. 
According to yet another preferred embodiment of the invention, the first 
and second fastener driver means include respective magazines for storing 
fasteners. Each of the magazines are attached to the mounting shoe. 
According to yet another preferred embodiment of the invention, the first 
and second fastener driver means are first and second compressed-air 
actuated fastener guns. 
Preferably, the fastener gun is a compressed-air actuated staple gun. 
According to another preferred embodiment of the invention, the handle 
includes a hollow grip section communicating with a source of compressed 
air. A hollow cross member is connected to the grip section for directing 
the compressed air into respective chambers of the first and second 
fastener guns. 
According to yet another preferred embodiment of the invention, firing 
means located in respective chambers is actuated by the trigger means, and 
operates to fire the respective fastener guns.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE 
Referring now specifically to the drawings, a fastener tool according to 
the present invention is illustrated in FIG. 1 and shown generally at 
reference numeral 10. The fastener tool 10 is particularly useful by dry 
wallers for applying a protective strip, such as a metal corner bead 11, 
to the outside edge of a corner 12 formed by two adjacent, intersecting 
walls 13 and 14 of sheet rock. The corner bead 11 is applied to the wall 
corner 12 before plastering by driving fasteners 15 (See FIGS. 2 and 3), 
such as staples or nails, into the corner bead 11 and walls 13 and 14. The 
fasteners 15 are inserted into each outer side 11A and 11B of the corner 
bead 11 and the adjacent walls 13 and 14 to ensure proper attachment of 
the corner bead 11 to the wall corner 12. 
As shown in FIGS. 1-4, the fastener tool 10 includes a handle 18, a 
mounting shoe 19, and first and second compressed-air or gas powered 
fastener guns 20A and 20B. The fastener guns 20A and 20B may be either 
staple guns or nail guns commonly known and used in the art. As best shown 
in FIGS. 1 and 4, the fastener guns 20A and 20B are connected to the 
handle 18 and mounting shoe 19 in perpendicular relation to each other for 
simultaneously driving fasteners 15 into the outer sides 11A and 11B of 
the corner bead 11 and intersecting walls 13 and 14. The fastener guns 20A 
and 20B include respective magazines 21A and 21B for storing the fasteners 
15. The magazines 21A and 21B are connected to the mounting shoe 19 by 
bolts, welding, or other suitable means. 
According to one embodiment, the mounting shoe 19 forms a substantially 90 
degree angle to fit adjacent the outside edge of the wall corner 12. The 
mounting shoe 19 acts to hold the corner bead 11 in position, and to align 
the fastener guns 20A and 20B such that the fasteners 15 are properly 
driven into the corner bead 11 and intersecting walls 13 and 14. In an 
alternative embodiment, a mounting shoe can be shaped to fit against a 
soft or curved wall corner, and may also include a crimper (not shown) for 
shaping the corner bead prior to attachment to fit the particular wall 
corner. 
As best shown in FIG. 1, the handle 18 of the fastener tool 10 includes a 
hollow grip section 22 and a communicating hollow cross member 23 joined 
to the grip section 22. The cross member 23 is joined at opposite ends to 
respective chambers 25A and 25B of the first and second fastener guns 20A 
and 20B. The grip section 22, cross member 23, and chambers 25A and 25B 
are fluidly connected together for receiving and containing compressed 
air. 
An air supply hose 30 is attached to the grip section 22, and communicates 
with a source of compressed air for injecting compressed air into the 
hollow grip section 22, cross member 23, and chambers 25A and 25B. The air 
supply hose 30 and compressed air source provide the required air pressure 
necessary to operate each of the fastener guns 20A and 20B. 
A trigger mechanism 32 is located on the grip section 22 of the handle 18 
for being depressed by a user to simultaneously fire each of the fastener 
guns 20A and 20B. As shown in FIG. 1, when the trigger mechanism 32 is 
depressed, a linkage assembly 33 actuates respective firing means 40 of 
the fastener guns 20A and 20B. 
The term "firing means" is defined herein as the critical interior element 
(or elements) of the compressed-air powered fastener gun which is actuated 
by the trigger mechanism in order to fire the gun. The firing means may be 
any such means employed by conventional fastener guns of the prior art. 
According to one embodiment, the firing means 40 includes a valve rod 41 
actuated by the trigger mechanism 32 when the trigger mechanism 32 is 
depressed. Although only the valve rod 41 is shown, it is understood that 
an identical valve rod operating in an identical manner is located in the 
chamber 25B of the fastener gun 20B. When actuated, each valve rod 41 
moves as indicated at 31, and cooperates with an assembly of interior 
O-rings and valves (not shown) to direct a burst of compressed-air from 
the respective chambers 25A and 25B to drive the fasteners 15 into the 
corner bead 11 and walls 13 and 14. Such firing means 40 is common in the 
art, and has been employed in compressed-air powered fastener guns such as 
that disclosed in U.S. Pat. Nos. 3,871,556 and 4,117,767. Alternative gun 
firing means are disclosed in U.S. Pat. Nos. 3,815,475 and 3,106,136. The 
complete disclosure and teachings of each of these prior patents are 
incorporated herein by reference. 
With regard to FIG. 1, when the trigger mechanism 32 is depressed, the 
linkage assembly 33 moves as indicated by the direction arrow 34 to 
actuate in unison the respective valve rods 41 of the fastener guns 20A 
and 20B. The actuated valve rods 41 cause the fastener guns 20A and 20B to 
fire simultaneously with sufficient force to drive the fasteners 15 into 
the corner bead 11 and intersecting walls 13 and 14. 
As will be appreciated by those of skill in the art, the particular means 
of firing the fastener guns 20A and 20B is not critical to the invention. 
Consequently, the linkage assembly 33 may include any structure operable 
to actuate the firing means 40 of the fastener guns 20A and 20B when the 
trigger mechanism 32 is depressed. 
In an alternative embodiment (not shown), the fastener tool may simply 
include two conventional fastener guns connected to a mounting shoe by 
suitable brackets or welding. Each fastener gun includes a separate 
compressed-air supply source and trigger mechanism. Thus, instead of 
firing the fastener guns simultaneously with a single trigger mechanism, 
as described above, the user would depress the trigger mechanism of each 
gun to drive the fasteners into the opposing sides of the corner bead and 
intersecting walls. The fastener tool of this embodiment may further 
include a center handle welded to the mounting shoe for allowing the user 
to hold the tool against the wall corner with one hand while depressing 
the trigger mechanism of each fastener gun with the other hand. 
A fastener tool is described above. Various details of the invention may be 
changed without departing from its scope. Furthermore, the foregoing 
description of the preferred embodiment of the invention is provided for 
the purpose of illustration only and not for the purpose of 
limitation--the invention being defined by the claims.