Note: Descriptions are shown in the official language in which they were submitted.
CA 02501582 2002-03-22
This application is a division of Canadian Patent File No.
2,378,270 filed March 22, 2002.
BACKGROUND OF THE INVENTION
The present invention relates generally to improvements in
fastener driving tools, and specifically to such tools used in the
installation of
trim, other decorative applications and finishing applications utilizing
relatively
small fasteners, fasteners made of relatively thin wire stock, and/or used
with
relatively small and/or delicate workpieces. The foregoing will generally be
referred to as "trim applications." Include in the present tool are several
features intended to make the manufacture, use andlor repair of such tools
more efficient.
Portable combustion powered tools for use in driving fasteners
into workpieces are described in commonly assigned patents to Nikolich, U.S.
Patent Nos. Re. 32,452; 4,403,722; 4,483,4?3; 4,483,4?4; 4,552,162; 5,197,646
and 5,263,439, all of which may be refqred to for further details. Such
combustion powered tools particularly designed for trim applications are
disclosed in commonly assigned U.S. Patent No. 6,016,622, which may be
referred to for further details. Similar combustion powered nail and staple
driving tools are available from ITW-Paslode under the IMPULSE~ brand.
CA 02501582 2002-03-22
Such tools incorporate a generally pistol-shaped tool housing
enclosing a small internal combustion engine. The engine is powered by a
canister
of pressurized fuel gas also called a fuel cell. A battery-powered electronic
power
distribution unit or electronic sending unit produces the spark for igaidon,
and a
S fan located in the combustion chamber provides for both an efficient
combustion
within the chamber, and facilitates scavenging, including the exhaust of
combustion by-products. The engine includes a reciprocating piston having an
elongate, rigid driver blade disposed within a piston chamber of a cylinder
body.
A wall of the combustion chamber is axially reciprocable about a
valve sleeve and, through a linkage, moves to close the combustion chamber
when
a workpiece contact element at the end of a nosepiece, or nosepiece assembly,
connected to the linkage is pressed against a workpiece. This pressing action
also
triggers the introduction of a specified volume of fuel gas into the
combustion
chamber from the fuel cell.
Upon the pulling of a trigger, which causes the ignition of the gas in
the combustion chamber, the piston and the driver blade are shot downward to
impact a positioned fastener and drive it into the workpiece. As the piston is
driven downward, a displacement volume enclosed in the piston chamber below
the piston is forced to exit through one or more exit ports provided at a
lower end
of the cylinder. After impact, the piston then returas to its original or
"ready"
position through differential gas pressures within the cylinder. Fasteners are
fed
into the nosepiece from a supply assembly, such as a magazine, where they are
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CA 02501582 2002-03-22
held in a properly positioned orientation for receiving the impact of the
driver
blade.
One operational characteristic of such tools employed in trim
applications is that commercially available fasteners are typically provided
in
elgongate strips of individual fasteners held together with adhesive, not
unlike
conventional office staples. It is common for such fasteners to become jammed
in
the nosepiece. Thus, provisions are made in known trim-type fastener driving
tools for the user to access the interior of the nosepiece to remove the
jammed
fasteners.
In one known embodiment, a front plate of the nosepiece assembly
is pivotable outward to permit full access to the interior of the nosepiece.
The
front plate is preferably pivotable to at least 90° relative to the
vertical operational
axis of the tool for enabling the operator to pull out the jammed fasteners
perpendicularly to the action of the piston. One drawback of such an
arrangement
is that if the operator neglects to relieve the spring pressure of the
magazine
r
against the fasteners, once the jam is cleared, additional fasteners may be
uncontrollably ejected from the nosepiece, potentially causing injury or
damage.
Another operational characteristic of known trim-type fastener
driving tools is that, to avoid user fatigue, designers are constantly
..trying to
improve the ergonomics of the tool, including reducing weight and adjusting
balance. One aspect of such a design objective is that the nosepiece has been
moved closer to the combustion chamber to reduce the height of the tool. A
3
' CA 02501582 2002-03-22
drawback of this type of design is that the pivoting action of the front plate
is
restricted, and can no longer reach a fully open position. This restricts
access to
the jammed fasteners, in that the user must work around the partially opened
front
plate to access the jam. However, an advantage of this restricted pivoting
action is
that if the magazine spring force has not been disconnected, upon clearing of
a
jam, fasteners ejected from the nosepiece are deflected by the front plate to
avoid
injury andlor damage.
Another operational characteristic of such tools is that significant
impact forces are generated in the combustion and driving of the driver blade.
Also, the tools are sometimes dropped from a height during use or transport.
These impacts have been known to damage the sensitive electronic components of
the tool, such as, but not limited to the electronic sending unit. To reduce
such
impacts, it is known to apply a shock absorbing caulk around the sending unit,
which in some tools is located inside the handle portion. However, a drawback
of
this technique is that the caulk is messy to apply during manufacturing, and
also
makes service and repair of the sending unit more difficult.
Still another operational characteristic of such tools is that it is
important to avoid firing the tool when the magazine is empty of fasteners: If
so,
the driver blade can cause a mark in the workpiece, which is very undesirable
in
appearance-intensive trim applications. It is known to provide magazines with
indicators of the impending depletion of the fasteners in the magazine.
However,
these known devices do not provide the number of fasteners remaining just
prior
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CA 02501582 2002-03-22
to the emptying of the magazine. Since operators of such tools often change
the type
andlor length of fasteners, it is desirable to have an accurate indication of
when the
magazine will become depleted.
Thus, the present invention seeks to provide an improved fastener
driving tool which provides for the deflection of ejected fasteners upon the
clearance
of a fastener jam, and also is fully operable for the clearance of more
complicated
jams, or jams of longer fasteners.
Another aspect of the present invention seeks to provide an improved
fastener driving tool which has a relatively sham profile, but is also fully
accessible
for clearing jammed fasteners.
Still another aspect of the present invention seeks to provide an
improved fastener driving tool in which the handle portion provides shock
absorption
to the electronic sending unit without the use of shock absorbing caulk.
A further aspect of the present invention is to provide an improved
fastener driving tool having a fastener magazine with an indicator of the
number of
fasteners remaining just before the magazine is depleted.
B,~tIEF SU11~MA,RY OF THE INVENTION
More particularly the invention in one aspect provides a powerful tool
constructed to axially drive a driver blade to impact and drive a fastener
into a
workpiece, comprising a nosepiece assembly including a black plate and a front
plate
combining to define a path for the driver blade, the front plate being
pivotably
moveable relative to the back plate between a closed position in which the
front plate
and the back plate are in contact with each other, and an open position. A
stop on the
front plate retains the front plate in a deflecting position and prevents
pivoting action
S
CA 02501582 2002-03-22
of the front plate to the open position. A disengagement means is provided for
disengaging the stop for enabling the front plate to reach the open position,
the
disengagement means being a noncircular pivot bore on the front plate defining
a first
pivot axis enabling engagement of the stop, and a second pivot axis enabling
disengagement of the stop.
Another feature of the invention provides a trim-type fastener driving
tool, which features a front plate which is pivotable relative to the
nosepiece to permit
access, and which has two jam clearing positions: a first position which
deflects
fasteners ejected after the jam is cleared, and a second, fully accessible
open position
which permits axial extraction of jammed fasteners. In addition, the handle
portion
is preferably provided in its interior with a resilient cushion for protecting
a delicate
item stored within the handle, such as an electronic sending unit, which
avoids the use
of shock-absorbing caulk. Preferably, the cushion is part of a resilient
gripping
surface found on the outside of the handle. Also, the magazine is preferably
provided
with an indicator of the number of fasteners remaining just before the
magazine
becomes depleted.
In an alternate embodiment, a powered tool constructed to axially drive
a driver blade to impact and drive a fastener into a workpiece includes a
handle
portion with an outer surface at least partially defining a grip, and an inner
surface at
least partially defining a chamber, preferably for an electronic sending unit.
The
handle portion includes a substrate having at least one aperture, and an
overmold
configured for forming a gripping surface on the outer surface, the overmold
also being configured for extending through at least one of the apertures
6
CA 02501582 2002-03-22
mto the chamber for forming at least one resilient mounting point for the
electronic sending unit.
In a further alternate embodiment, a powered tool constructed to
axially drive a driver blade to impact and drive a fastener into a workpiece
includes a nosepiece assembly including a back plate defining an aperture
through
which fasteners are fed for engagement with the driver blade, a front plate at
least
partially covering the aperhue, and a magazine for dispensing fasteners to the
aperture. The magazine has an indicator for indicating how many fasteners are
remaining just prior to the magazine becoming empty.
BRIEF DESCRIPTION OF THE SEVERAL VIEVYS OF THE DRAWINGS
FIG. 1 is a fragmentary perspective view of the present tool,
illustrating the nosepiece assembly and the magazine;
FIG. 2 is a side view of the structure of FIG. 1;
FIG. 3 is a side view of the tool of FIG. 1, with portions omitted for
clarity;
FIG. 4 is a side view of the tool of FIG. 1 illustrating the deflection
position;
FIG. 5 is a view of the tool of FIG. 4 shown in a first partially
disengaged position;
7
CA 02501582 2002-03-22
FIG. 6 is a view of the tool of FIG. 4 shown in a second partially
disengaged position;
FIG. 7 is a view of the tool of FIG. 4 shown in a fully opened
position;
FIG. 8 is a verkical section of the handle portion showing the
electronic sending unit exploded away; and
FIG. 9 is a perspective view of the embodiment of FIG. 8.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIGs. 1 and 2, a combustion powered tool suitable
for driving trim-type fasteners is fragmentarily shown and generally
designated
10. It will be understood that features described below are particularly
suitable for
trim-type fasteners, however it is also contemplated that they may find
application
with combustion powered tools used for other applications. The general
appearance and operational details of such combustion powered tools for both
general and trim-type applications are described in greater detail in the
patents
which have been incorporated by reference.
In FIG. 1, the main illustrated components are a nosepiece assembly
12 and a fastener magazine 14. The tool 10 is shown in a generally vertical
orientation, with fasteners 16 driven through a lower end 18 of the nosepiece
assembly 12 into a workpiece 20, however other orientations of the tool 10 are
8
CA 02501582 2002-03-22
contemplated as known in the art. Opposite the lower end 18 is an upper end 22
of
the nosepiece assembly 12.
Included in the nosepiece assembly 12 are a generally planar back
plate 24 and a generally planar front plate 26, which combine to define a path
or
track 28 for a driver blade 30. The track 28 extends the full length of the
nosepiece assembly 12 to the lower end 18. A front plate support 32 is secured
to
the back plate 24, preferably by fasteners (not shown) passing through
corresponding bores 34 in the support and the back plate. The main purpose of
the
front plate support 32 is to provide a pivot point or axis 36 for the front
plate 26.
However, other arrangements providing such a pivot axis are contemplated,
including providing a pivot point integrally formed on the back plate 24. In
the
preferred embodiment, the pivot axis 36 is defined by a pair of spaced, co-
axial
bosses 38 each defining a throughbore 40. At least one of the throughbores 40
is
internally threaded or otherwise configured for lockingly receiving a pivot
pin 42.
An upper end 44 of the front plate support 32 also helps define the track 28.
r
As described above, an important concern of users of such fastener
tools 10 is that there should be access to the interior of the nosepiece
assembly 12
to enable the clearance of jammed fasteners. Specifically, there is an
aperture 46
(shown hidden in FIG. 3) in the back plate 24 through which fasteners 16 are
urged from the magazine 14. This aperture 46 often becomes filled or jammed
with at least one fastener 16 and must be cleared for the resumption of normal
9
CA 02501582 2002-03-22
operation of the tool 10. In the preferred embodiment, such access is obtained
by
having the front plate 26 be pivotable relative to the back plate 24.
Referring now to FIGs. 1-3, this pivoting action begins from a closed
position in which the front plate 26 and said back plate 24 are in contact
with each
other, which is also the normal operating position of the tool 10. The closed
position is maintained by a releasable spring clamp (not shown) which, in the
preferred embodiment, is an over-center cam type well known in the art of trim-
type fasteners for this purpose. The clamp is mounted to eyelets 48 on the
front
plate 26, retainer arms 50 on the back plate 24, and a recess 52, also located
on the
front plate. Other mounting formations are contemplated for securing any
suitable
clamp in operational relationship to the nosepiece assembly 12.
In the preferred embodiment, the pivoting action is obtained by an
upper end of the front plate 26 being provided with a pivot bore 54 which is
preferably noncircular, and which accommodates the pivot pin 42. The pin is
shown with a hex recess 56, and is preferably threaded at its tip to engage
the
throughbore 40 in the left boss 38L, after it slidingly passes through the
throughbore 40 in the right boss 38R and the pivot bore 54. While the above-
described arrangement is preferred, other structures for obtaining a pivoting
relationship between the front plate 26 and the rear plate 24 are
contemplated,
such as, but not limited to having the pin 42 fixed to the front plate and
engaged in
U-shaped grooved bores 40, having two bores 40 on the front plate and the
pivot
CA 02501582 2002-03-22
bore 54 on the rear plate, and having the two bores 40 located elsewhere on
the
nosepiece assembly 12 or on the tool 10.
Referring now to FIGs. 3 and 7, the front plate 26 is generally freely
pivotable between the closed position (FIG. 3) and an open position (FIG. 7).
In
the present application, the "open position" will be referred to as a fully
open
position of the front plate 26 is which fasteners 16 jammed in the aperture 46
are
extractable along a longitudinal axis "L" (FIG. 7) generally perpendicular to
the
plane of the back plate 24. In the preferred embodiment, the front plate 26 in
the
open position is at an angle a of least 90°, however other angles are
contemplated
depending on the height of the fasteners 16.
As described above, one drawback of prior art trim-type tools is that
in some cases, the user forgets to release the spring bias exerted by the
magazine
14 against the fasteners 16 ready to be driven by the driver blade 30. Upon
the
extraction of the jammed fastener, the remaining fasteners (sometimes in strip
form, as seen in FIG. 7) can be ejected from the aperture 46 under force,
which
may cause injury and/or damage.
Referring to FIG.I, an important feature of the present nosepiece
assembly 12 is a stop 58 configured for preventing the otherwise free pivoting
action of the front plate 26 to the open position and creating an interim
deflecting
position for the front plate 26 between the closed position and the open
position.
In the preferred embodiment, the stop 58 is secured to the front plate
2~, preferably integrally, and projects generally radially from the pivot bore
54.
11
CA 02501582 2002-03-22
the stop 58 also takes the general form of a right angle, having a pair of
walls 60.
Other types of attachment and configuration for the stop 58 are contemplated
as
are known in the art for enabling the stop to engage the nose assembly 12 for
preventing the front plate 26 from reaching the open position.
Referring now to FIGs. 1 and 4, the stop 58 engages a surface 62 on
the front place support 32 to define an interim or deflection position. This
position
is so named because of the way an inner surface 64 of the front plate 26 will
deflect any ejected fasteners 16 which are released by the user pulling the
jammed
fastener from the aperture 46. The deflection position, in which an angle a is
preferably in the range of 69-?0°, tends to protect the user and
surrounding
property from injury and/or damage from ejected fasteners. A fragmentary
fastener strip 16 is shown being ejected and deflected along a path 65. The
deflection position is also useful in deflecting broken pieces of jammed
fasteners
which may be ejected from the aperture 46. In addition, in many cases a jam
may
be cleared without opening the front plate 26 to the open position (FIG. ?).
Referring to FIGs. 1 and 3-?, another feature of the present tool 10 is
that it has a relatively low profile, in that the nosepiece assembly 12 is
mounted
relatively close to the combustion chamber (not shown). Due to this
arrangement,
special efforts must be made to provide the front plate 26 with the ability to
pivot
fully to the open position (FIG. ?). In addition, to reach the open position,
the
nosepiece assembly 12 is preferably equipped with a structure for enabling the
disengagement of the stop 58 from the surface 62.
12
CA 02501582 2002-03-22
In the preferred embodiment, the disengagement structure takes the
form of the noncircular pivot bore 54, which defines a first pivot axis 66 for
pivoting action to the deflecting position (FIG. 4), and a second pivot axis
68
(FIGs. 6 and 7) for enabling disengagement between the stop 58 and the surface
62 for achieving the open position. In addition, the pivot bore 54 also
defines a
transition surface 70 to allow the user to shift the front plate 26 downward
and
forward so that disengagement is achieved. This shift can be seen in FIG. 5,
where it is evident that the stop 58 has now been moved beneath the surface
62.
Referring now to FIG. 6, once disengagement has occurred, the front
plate 26 is now free to pivot about the second axis 68 to the open position
(FIG.
7), in which the stop 58 is totally out of contact with the front plate
support 32. It
will also be seen from FIG. 3 that the pivot bore 54 is generally heart-
shaped,
although other noncircular shapes are contemplated for achieving the dual
pivot
points and the above-described disengagement.
Referring now to FIGs. 1 and 2, another feature of the present front
plate 26 is at least one aiming formation 72 for facilitating the location of
the
nosepiece assembly 12, aad specifically the lower end 18 relative to the
workpiece
for accurate placement of fasteners 16. The aiming formation resembles the
rear sight of a firearm, and defines a pair of bars between which the fastener
will
20 be placed by the driver blade 30. Additional aiming formations are
contemplated
which enhance line of sight accuracy in the placement of fasteners 16.
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CA 02501582 2002-03-22
Refen~ing now to FIG. 2, still another feature of the present tool 10 is
that the magazine 14 is provided with an indicator 74 for indicating how many
fasteners are remaining just prior to the magazine becoming empty. Preferably,
the present indicator 74 will not be elective until there are only about 15 or
fewer
fasteners left in the magazine 14, with the number vatsring depending on the
type
and size of fastener employed in the tool 10.
More specifically, the preferred form of the indicator 74 utilizes a
follower 76 which is a known component of magazines, being used to exert the
spring force upon the strip of fasteners to urge them toward the aperture 46.
1'he
magazine 14 also includes at least one window 78 which provides a rough
indication of the number of fasteners remaining, and may also be provided with
a
visual indicator or scale 80 of the number of remaining fasteners. As the
number
of fasteners 16 in the magazine 14 dwindles, the follower 74 will become
visible
through the window 78. It is preferred that the indicator 74 take the form of
a
series of spaced dots or marks 82, each representing a fastener. As the dots
82
disappear behind a wall 86 of the magazine 14 as the follower approaches the
aperture 46, the user can count the remaining dots to determine the number of
remaining fasteners. It is also preferred that the very last dot 84,
representing the
last fastener in the magazine 14, be differentiated as by size or color, from
the
other dots, to alert the user to reload the magazine. It is also preferred
that a
reference line 88 is provided on the magazine wall 86 associated with, and
14
CA 02501582 2002-03-22
preferably adjacent the row of dots 82 to facilitate the user's identification
of the
number of remaining fasteners 16.
Referring now to FIGs. 8 and 9, another feature of the present tool
relates to the construction of a handle portion 90 which provides a grip for
the
5 user, and which also defines a chamber 92. The handle portion 90 includes an
outer surface 94 for providing the grip, and an inner surface 96 for defining
the
chamber 92.
In the preferred embodiment, the handle portion 90 more specifically
includes a relatively stiff or rigid substrate 98 defining the inner surface
96 and the
10 chamber 92, and having at least one aperture 100, and an overmold 102
configured
for forming a gripping surface on the outer surface 94. An important feature
of the
present handle portion 90 is that the overmold 102 is configured for extending
through the at least one aperture 100 into the chamber 92.
As is known in the art, tools of many types, and other consumer
articles are made with overmolds of relatively more resilient material to
enhance
gripping. Using known molding technology, the substrate 98 is made of a
relatively stiff or rigid material, such as ABS polycarbonate, or the like,
and the
overmold 102 is made of a relatively resilient material, such as an elastomer.
As
an example only of the relative resiliencies of the substrate 98 and the
overmold
102, the preferred substrate has an approximate Durometer Shore Hardness of
85,
and the overmold approximately 45. Although many materials are suitable,
provided they have the desired resilience, a preferred overmold material, due
to its
CA 02501582 2002-03-22
ability to bond well with ABS polycarbonate, is provided by Diamond Polymer of
Ohio, under the trademark SOFT FLEX.
While it is well known to provide gripping surfaces by overmolding,
an additional feature of the present handle assembly 90 is that the overmold
102
also provides a shock absorbing function to an article located within the
chamber
92, such as the electronic sending unit 104 of the present tool 10. More
specifically, during the molding process, the overmold 102 flows through the
apertures 100 and forms along akeady existing structural support ribs 106, to
form
a cushion distance 'D' by projecting past and preferably radially inwardly
beyond
the relatively stiff ribs 106. In this manner, the overmold 102 forms at least
one
resilient mounting point 108 for the sending unit 104.
As best seen in FIG. 9, the ribs 106 are generally "U"-shaped to
partially circumscribe the sending unit 104 and more snugly retain it within
the
chamber 92. Through the use of the overmold 102 creating the resilient
mounting
points 108, a tight friction fit is provided for the sending unit 104 which
also
protects against shock impact, and is an integral piece of the gripping
surface on
the outer surface 94.
Thus, it will be seen that the present tool 10 features a pivot
stop/disengagement mechanism for providing both an open position and an
interim, deflecting position. The former is useful for clearing difficult jams
and/or
jams of larger fasteners, and the latter is useful for deflecting stray
fasteners
released during the clearance of more normal jams. In addition, an indicator
has
16
CA 02501582 2002-03-22
been provided on the magazine follower which accurately indicates the number
of
fasteners remaining just before the magazine becomes empty. Further, the
handle
portion is configured so that the same resilient material forms a soft grip,
while
providing a shock absorbing function to fragile components located within the
handle portion.
While specific embodiments of the trim-type fastener driving tool
of the present invention have been shown and described, it will be appreciated
by
those skilled in the art that changes and modifications may be made thereto
without departing from the invention in its broader aspects and as set forth
in the
following claims.
17
