Note: Descriptions are shown in the official language in which they were submitted.
CA 02306618 2004-06-22
NOSEPIECE SHIELD FOR COMBUSTION POWERED TOOL
RELATED APPLICATION
This application is related to Canadian Patent File No. 2,273,465 filed June
2, 1999 and entitled NOSEPIECE SHIELD FOR COMBUSTION POWERED TOOL.
BACKGROUND OF THE INVENTION
The present invention relates generally to portable combustion powered
fastener driving tools and specifically to a shield to protect a workpiece-
contacting
element of a nosepiece of such tools.
Portable combustion powered tools utilized for driving fasteners into
workpieces are described in commonly assigned patents to Nikolich U.S. Pat Re.
No.
32,452 and U.S. Pat Nos. 4,522,162; 4,483,473; 4,483,474; 4,403,722;
5,197,646; 5,263,439;
5,558,264 and 5,687,899, all of which may be referred to for further details.
Similar
combustion powered nail and staple driving tools are available commercially
from ITW-
Paslode of Vernon Hills, Illinois under the IMPULSE~ brand.
1
CA 02306618 2000-04-26
Such tools incorporate a generally pistol-shad tool housing e~aclosing a small
internal combustion engine. The engine is powered by a canister ofpressutized
fuel gas, also
called a fuel cell. A battery-povc~ered electronic power distribution unit
produces the spark
for ignition, and a fan located in the co~oabustion chamber provides for both
an e~cient
combustion within the chamber, and facilitates scavenging, including the
exhaust of
combustion by products. The engine iuacludes a reciprocating piston with an
elongated, rigid
driver rod disposed within a cylinder body.
A valve sleeve is axially reoipmoal about tha cylinder and, through a linkage,
moves to close the combustion cl~nber when a work contact element at the end
of the
linkage is pressed against a workpiece. This pressing action also triggers a
fuel metering
valve to introduce a spcCified volume of fuel into the closed wmbustion
chamber.
Upon the pulling of a trigger switch, which causes the ignition of a charge of
gas in the combustion chamber of the engine, the piston and driver rod arc
shot downward
to impact a positioned fastener and drive it into the workpiece. The pisto~a
then ndiros to its
original, or "ready" position, through differential gas pmessturs within the
cylinder: Fasteners
are fed magazine-style into the nosepiece, where they are held in a properly
positioned
orientation for receiving the impact of the driver rod. Upon ignition of the
combustible
fueUait m~iictu~te, the combustion in the ohambe~r causes the acceleration of
the piston/driver
rod assennbly and the penetration of the fastener iunto the workpiece if the
fastener is present.
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CA 02306618 2004-06-22
The nosepiece of the tool includes a pair of upper and lower guide members
for guiding the driver rod towards the uppermost nail of a nail strip.
Fasteners are
guided to the workpiece by a workpiece end of the nosepiece.
A disadvantage of conventional combustion powered tools of this type is
that the nosepiece is not enclosed by the housing. Therefore, in some
applications,
damage can occur to the nosepiece if, for example, a workman dropped the tool.
Also,
the nosepiece is adjustable to vary the depth that the fastener is driven into
the
workpiece. These adjustments are typically made by the operator of the tool.
Thus,
there is a need to protect the nosepiece and the corresponding components of
the
nosepiece, from external forces. There is also a need to protect the depth
adjustment
from inadvertent impact or interference by the operator or others. In
addition, there
is a need to provide protection to the nosepiece of a combustion powered tool
of the type
which is used to drive fasteners into drywall channel. Drywall channel
provides a
generally restricted area for operational manipulation of combustion tool
nosepieces.
As a consequence, this invention seeks to provide an improved portable
combustion powered fastener driving tool with a shield to protect the
nosepiece of the
tool from impact.
Further, the present invention seeks to provide an improved portable
combustion powered fastener driving tool with a nosepiece shield containing
access
openings for access to the nosepiece depth adjustment.
3
CA 02306618 2004-06-22
The present invention further seeks to provide an improved portable
combustion powered fastener driving tool with a nosepiece shield configured to
be
operable within the confines of drywall channel while still permitting the
unobstructed
operation of the nosepiece.
BRIEF SUMMARY OF THE INVENTION
The above-listed objects are met or exceeded by the present combustion
powered tool for driving fasteners featuring a shield which is fixed to the
tool housing
and is configured to encompass the nosepiece without impairing its operation
for use in
narrow tracks such as drywall tracks. Access openings are provided in the
shield to
provide access to the fastener driving depth adjustment mechanism.
The invention provides a combustion powered tool comprising a housing
having a main chamber, a power source having a combustion end and a lower end
enclosed in the main chamber and a rod driven by the combustion end of the
power
source with means for feeding fasteners sequentially for engagement with the
rod. A
nosepiece has a tool end, a workpiece end opposite the tool end and depending
from the
lower end of the power source. The nosepiece is configured for receiving the
rod from
the lower end of the power source and for guiding the rod toward a workpiece.
A
workpiece-contacting element is slidably mounted on the nosepiece and
protecting means
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CA 02306618 2004-06-22
is provided for protecting the nosepiece and the workpiece-contacting element,
the
protecting means being constructed and arranged to define a cavity between the
nosepiece and the protecting means and having an upper portion. The upper
portion
includes a rear opening for circumscribing a portion of the nosepiece and is
tapered from
a top end to a transition point and has a lower portion depending from the
transition
point and has a small diameter necked down configuration.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a fragmentary side view of a combustion powered fastener tool
with the present nosepiece shield, partially cut away for purposes of clarity;
FIG. 2 is a fragmentary side view of a combustion powered fastener tool,
partially cut away for purposes of clarity, with an exploded view of the
present nosepiece
shield;
FIG. 3 is an isolated side view of the present nosepiece shield;
FIG. 4 is an isolated top view of the present nosepiece shield showing the
retaining ring;
FIG. 5 is an isolated back view of the present nosepiece shield;
FIG. 6 is an isolated view of an alternative embodiment of the present
nosepiece shield;
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CA 02306618 2000-04-26
FIG. T is a side elevational view of a combustion powered tool suitable for
use
with an alternate embodiment o~ the pzcscnt nosepiece shield,
FIG_ 8 is a front perspective elevational view of the nosepiec shield of FIG.
7
shown assembled on a tool, with portions omitted for clarity;
FIG. 9 is a front elevations) vicwv of the nosepiece shield of FIG. 8;
FIG. 10 is a bottom view of the nosepiece shield of FIG. 8;
FIG.11 is a section taken along the line 11-11 of FIG. 10 and in the direction
indicated generally; and
FIG. 12 is a rear clevational vices of the nosepiece shield of FIG. 8.
DETAILED DESCRIPTION OF ~ IN«EN'ITON
Referring now to FIGS. l and 2, a combustion~owcred tool of the type suitable
for use with the present invention is generally designated 10. The tool 10 has
a housing 12
including a maim power source chamber 14 dimensioned to enclose a self-
contained internal
combustion power soune 16, a fuel cell charnbcr 18 (show in phantom) generally
parallel
with and adjacent the main chamber 14, and a handle portion 20 extending
fi~oxn one side of
the fuel cell chamber and opposite the main chamber.
In addition, a fastener magazine 22 is positioned below the handle pvrtiot~
and
extends to a nosepiece 26 depending from a lower end 28 of the main chamber
14.
Preferably the magazine 22 accommodates a strip of nails, as shown, but
alternatively rnay
6
CA 02306618 2004-06-22
accommodate a coil of nails as shown in U_S_ Patent No. 5,558,264. A battery
(not shown)
is provided for providing electrical power to the tool 10, and is xeleasably
housed in a tubular
comp$rnnent (not shown) located iw the handle portion 20.
As used herein, "lower" and "upper" are used to iefcr to the tool 10, 102 in
its
S operational orientation as depicted in FIGS. 1, 2 and ?, and "fiont" is used
to refer to the Left
side of the tool 10,102 as depicted in FIGS. I, 2 and ?; however it will be
understood that
this invention may be used in a variety of orientations depending on the
application.
Opposite the lower end 2$ of the maim chamber is a combustion end 30, which is
provided
with a plurality of air intake vents 32.
A pressurized liquid hydrocarbon fuel, such as MAP~,~LS contained within a
fuel cell (not shown) and pressurized by a propellant as is known in the art.
A fluid
communication is established between the fuel cell and the valve. In a
preferred
embodiment, a mechanically operated valve is used, such as that currently
arrailable iua an
IIvIPULSE~ toot sold by 1TW-Paslode. In other embodiments, an elcetro-magnetic
solenoid
type fuel metering valve may be used.
Returning to the ~anain chamber 14, a cylinder head 34 is disposed at the
combustion end 30 of the main chamber, and defines an upper end of a
combustion chamber
36, also located at the upper and of the chamber, and provides a mounting
point for a head
switch 38 (shown in phantom), a spark plug 40, an electric fan motor 42, axed
a sealing O-ring
44.
7.
CA 02306618 2000-04-26
A main or combustion chamber fan 46 is attached to an armature or power
shaft 48 of the motor 42 at a first end SO of the armature. Located within the
combustion
chamber 36 to axially rotate, the fan 46 thus enhances the combustion process
by mixing the
fuel and air, and also facilitates cooling and scavenging- 'fhc fan motor 42
is controlled by
the head switch 38, as disclosed in mop detail in the prior patents
incorporated by reference.
The fan 46 serves as a main air flow enhancing device for exihanciug the flow
of air within
the combustion chamber 36.
A generally cylindrical, reciprocating valve member or valve sleeve 52 is
moved within the mama chamber 14 by a workpiex-contactmtg element 54 slidably
mounted
on an outside of the nosepiece 26 using a link~agc 56. Sidcvv~alls of the
combustion chamber
36 are defined by the valve n~acmber 52, the upper end of which sealingly
engages the O-ring
44 to seal the upper end of the combustion chamber. A lower portion 58 of the
valve
member 52 eircunnscribes a generahy oYlindrical cylinder body 60. An upper end
of the
cylinder body 60 is provided with azi exterior O-ring 62 which engages a
corresponding
IS portion 64 of the valve member $2 to seal a lowtY' end of the combustion
chamber 36.
Within the cylinder body 60 is reciprocally disposed a piston 66 to which is
attached a rigid, elongated driver and 67 used to drive fasteners 68 (shown
hidden in FIG. 1 ),
transported from the rtiaga2ine 22 and suitably positioned in the nosepiece
26, into a
wotlopiecc. As a trigger 69 is pulled, a signal is generated from the central
electrical
z0 distn-bvtion and control unit (not shown) to cause a discharge at a spark
gap of the spark phi8
8
CA 02306618 2000-04-26
40, which ignites fuel which has been injected into the combustion chamber 36
and
gar frag~nentcd by the fan 46. In response, the piston 66 is driven toward a
lowtr
end of the c~rlinder 60. As the piston 66 approaches the lower ead, the driver
rod 67 will be
guided into the xiosepiece 26 and impact a fastener 68 held above a workpiece
by the
nosepiece. Impact of the driver rod 67 drives the fastener into a workpiece ar
substrate.
~'o regulate the use of fiuel, the fnin~g of the tool 10 will not occur unless
the
nosepiecx 26 is pressed against a workpiecc. Suclt placement causes the
linkage 56 to be
pushed upward, which moves the valve mcmbex 52 to seal the combustion chamber
36, and
also moves linkages (not shown) which operate the mechanical fuel valve.
Details
to concerning sealing of the crnnbustion chamber 36, and related mechanisms
may lx found in
the previously mentioned Ndcolich patents, which are incorporated by
reference.
A lower end of the cylind,cr body b0 defines a seat 70 for a bumper 71 which
defines the lower limit of travel of the piston 66. At the opposite c~nd of
the cylinder body
60, a piston stop ring 72 is axed to limit the upward travel of the piston,
66.
Referring now to FIG. 2, a shield 73 of a preferred embodiment of the present
invention protects the xiostpiece 26 with its comcspoZ~ding components. At a
tool end 74 of
the nosepiece 26 is a retaining ring 75 fixed to the lower end 28 of the power
source 16 by
at least one screw 76 or other threaded fastener. The nosepiece 26 fiuther
includes a pair of
front and rear guide mcrnbers 78 and 79 disposal below the retaining ring 75.
In a preferred
2o embodiment, the rear guide member 79 is actually a fxont surface of the
magazine 22.
9
CA 02306618 2004-06-22
Mating surfaces (not shown) of the front and rear guide members 78 and 79 are
formed
with semi-circular grooves. Upon assembly of the nosepiece 26, the semi-
circular grooves
of the mating surfaces form a guide passage (not shown) having a cross
sectional shape
corresponding to the shape of and coaxial with, the driving rod 67 and
fasteners 68 for
guiding the driving rod and the fasteners.
Through the guide passage, the fasteners 68 are guided to the workpiece,
which is located at the workpiece end 80 of the nosepiece 26. A rear end
portion of the
semi-circular groove of the rear guide member 79 is tapered to form a notch
(not shown)
for receiving the fastener 68 from the magazine 22. The nosepiece 26 also
includes the
workpiece-contacting element 54 which extends generally vertically in spaced,
generally
parallel relationship to a front surface 81 of the front guide member 78. A
lower portion
82 of the linkage 56 is fixed to the workpiece contacting element 54 by at
least one and
preferably two depth of drive adjustment screws 84. The screws 84 pass through
a
vertically extending slot 86 in the workpiece contacting element 54. By
temporarily
loosening the screws 84, the relative vertical position of the element 54 and
the linkage
portion 82 may be adjusted as is known in the art. Further details of the
nosepiece
arrangement may be found in U.S. Patent No. 5,687,999 which may be referred to
for
further details.
Referring now to FIGS. 3 and 4, the shield 73 has a top end
88, a bottom end 90 and a generally tubularshape configured
to
circumscribe the nosepiece 26. The shield 73 is preferably
of
durable construction and can be manufactured example,from 16-
for
CA 02306618 2000-04-26
gauge 1050 cold rolled steel. The use of other equivalent engineered.
materials or metals is
also contemplated The retaining nn8 75 is fastened to the top end 88 of the
shield 73, and
ys gored for attachment to the lower end 28 of the power source 16. In length,
the shield
73 is configured so that when the nosepiece 26 is pushed against the
workpiece, and the
.~,~iece contacting element 54 is completely retracted, the bottom eQd 90 of
the shield 73
occupies a position substantially flush with the workpiece. A longitudinal
pcriphet'ai wall
92 of the shield 73 is inclined from the top end 88 to the ~~' end 90 to form
a geae~ally
hollow inverted. conical shape~ Tbas shape accommodates the nosepiece 26, the
movement
of the workpie~~l~~g element S4, the linkage portion 82, and the screws 84,
yet
1 o provides good visibility of the worlcpiece.
fore specifically; the retaining ring 75, which is a previously existing
component of the tool 10, has a generally circular shape with notches 75a def
ned therein to
accommodate parts of the nosepiece 26, and the direr rod 67. Additionally, the
r~in~n~g
ring 75 contains a hole 91 for accepting the screw 76 to attach the retaining
ring 75 to the
15 lower end 28 of the power source 16. To fasten the shield ?3 to the
retaining ring 75, the
shield 73 is preferably 'welded ~~g 'tee top etld 88 to at least 75% of a
perimeter of the
~g ring 75. Alternatively, the shield 73 could be stamped or molded in one
piece, or
nnolded into a die cast housing which could be part of the main body.
To protect the four sides 93 of the nosepiece 26 {best seen in FICr2), the
shield
20 73 is constructed and an-anged to cover at least three of the sides, the
fourth side being
11
CA 02306618 2000-04-26
abuttingly engaged by the fastener magazine 22_ Rearward facing edges 92a, 92b
of the wall
92 def ne a space for accommodati~otg the magazine 22.
A.s shown in FIG S, at least one access aponi~dtg 94 (preferably three are
provided) in the shield 73 is provided for access to the drive adjustment
screws $4 on the
nosepiece 26. Each access opening 94 is constructed and arranged so that only
one of the
drive adjustment screws 84 can be accessed at a time. Fort' example, one of
the screws 84 can
be accessed while the nosepiece 26 is in an unretxacted position, and the
other can be
accessed when the nosepiece 26 is ~cetracted, as occurs when the tool is
pressed against the
workpiece. Multiple access openings 94 are pravidod to allow the same
nosepiece shield 73
to be used on a variety of tools 10. Furthermore, the shield 73 is constructed
to define a
cavity 95 between the nosepiece 26 and the shield 73 to allow the drive
adjustment.
F1G. 6 shows an alternative embodiment of the present shield whicb is
generally designated 73a. Shared components between the shields 73 a~ad 73a
are indicated
with the identical reference numerals. The shield 73a is designed for use on a
smaller
combustion type tool tiled for driving fasteners 68 into more delicate
workpioccs such as in
him work. An opening 96 is provided in the shield 73a for access to a depth
adjustment of
the nosepiece 26. A, notch 98 in the shield 73a allows access to a screw 99
(shown in FIG.
1) for the fastener magazine 22. As is the case with the shield 73, the shield
73a has a
generally curved lower edge 100 which allows the tool to be angled relative to
the workpiece
for application when the fastener 68 needs to be driven on an angle. It is
contemplated that
12
CA 02306618 2000-04-26
over. such openings and notches 94, 96, 98, may be added when necessary to fit
combustion
powered tools of various configurations.
Referring now to FTGs. 7 and 8, a combustion powered tool designed for use
with an alternate embodiment of the shield 73 is generally designated I02. The
tool 102 is
similar in operation to the tool 10, and corresponding components are
designated with
identical reference numbers- p m~ d~~ f~'~ of the tool 102, which is
preferably sold by TTW Reamsct/Red Head of Wood Dale, IL under the t~rad~rk
'fR.AI~AST~, is that it is dcsigaed specifically for driving spccialized
fasteacrs known as
pins tbrongh drywall track 104 and into concrete, steel or other substtatc
matcrial. In this
1 o manner, the drywall track, which is basically steel formed into an open
topped "U" chatmel,
is secured to the substrate, and may klave supporting metal vcrtical wall
supports or studs
and; evcatually drywall mounted to it.
Accordingly, the tool 102 has a noscpiece 106 wbuich is configured to operate
the same as the nosepiece 26 and with .corresponding components, including a
tool end 74
and a workpiece end 80, and in addition, is spccially designed to havc a
s~analler diameter
profile to be easily insettable into the opcn uppcr end of the drywall track
104. In addition,
and referring now to FIGS. 8 and 11, a workpiecc contacting element 108 has
been speciaFy
designed to fit within a smaller working diameter, as described below. To
provide the
protective advantages of the nosepiece shield 73 to the tool 102, a modified
shield is
provided, and is generally designated 110.
13
CA 02306618 2000-04-26
Referring now to FIGS. 8-12, the shield 110 is designed to protect the
nosepiece 106 and the workpiece contacting element 108 from damage, and has a
top end
112, a bottom end 1I4, and a generally tubular shape configured to
circumscrt'be the
nosepiece 106. The shield 110 is preferably of durable construction, and can
be
S manufactured, for example, franc 16-gauge 1050 cold rolled steel. The use of
other
oquivalent engineered materials or metals is also coat~mplated, and. it is
further contemplated
that the shield 110 may be molded into a die cast housing which could be part
of the main
body.
At the top end 112, the shield 1 x 0 is provided with a generally Planar,
radially
inwardly projecting flange 116 which defncs a central opening 118 (best seen
in FIG. 8)
configured to circumscn'be an upper end of the nosepiece 106. In addition, the
flange 116
serves as the attachment point for the shield 110 to the lower end 28 of the
power sout~ee 16.
An opening 120 (best seen in F1~G. 8) is ptovidod in the flange 116 for
receiving a threaded
fastener 76 or other type of fastener for securing the shield 110 to the tool
102.
In: overall shape, the shield 110 is generally conical, having an upper
portion
122 and a lower portion 124. The upper portion 122 tapers from a relatively
wide point at
the top end 112 to a shoulder 126 which acts as a h~asition point between the
upper portion
122 and the Lower portion 124. In comparison to the upper portion 122, the
lower portion
is smaller in diameter, havin8 a "necked down" con~guratian, and is generally
cylizidrical
14
CA 02306618 2000-04-26
in Shape, an interior 128 of the lower portion being inn communication with an
interior 130
of the upper portion 122.
Referring now to FIG. 12, a rear opening 132 of the shield 110 is defined by
rear edges I34 of the upper portion 122, the shoulder 126 and a top segment of
the lower
portion 124. In configuration, the rear opening 132 is designed to cir~umscn-
be the upper
end of the nosepiece 106 (best seen in FIG. 7).
Refcnring now to FIGS. 8-10 and 12, opposite the rear opening 132 is an access
opening 136 in the upper pardon 122. The access opening 136 is provided for
access to the
drive adjustment screws 84 on the nosepiece 106. In the preferred embodiment,
the access
opening 136 is configured to be large enough to access both adjustment sciews,
however it
is contemplated that the shape and/or number of openings 136 may change to
suit the
application.
Referring now to FIGS. 8 and .11, while the upper end 122 is substantially
spaced from a majority of the nosepiece 106, and, like the shield 73, defines
the cavity 95
between the shitcld anti the nosepiece, the lower end 124 is dimensioned to be
su~ciently
small in diameter to be easily inserted into the open upper and of the drywall
track 104 to
accurately place the pins where nxded. Further~aaore, the lower end 124 is
also dimensioned
so that the operator or user can easily see where the pin will be driven,
without unnecessary
obstructions from the shield 110. Thus, the lower end 124 is preferably
dimensioned to be
of a diameter just large enough to slidingly accommodate the movement of the
worlcpiece
CA 02306618 2000-04-26
contaetin~ element 108 relative to the nosepiece lb6 to allow those components
to freely
operate, yet not provide additional space to obstruct the ability of the
nosepiece 106 to be
readily inserted into the drywall track.
Tn addition, like the shield 73, the shield i 10 is configured so that when
the
nosepiece 106 is pushed against the workpiece, and the workpicce contacting
element 108
is completely retracted, the bo~a~. ~d x 14 of the shield 110 occupies a
position
substantially Mush with the worl~iece.
Whle a particular ambo~t~t of the shield for the nosepiece of a combustion-
powered tool of the invention has been shown and d~-bed, it will be
appreciated by those
1 o skilled iu the art that chaages and modifications may be made thereto
without departing from
the invention in its bmader aspects and as set forth in the following claims.
16
