Note: Descriptions are shown in the official language in which they were submitted.
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This application is a division of application 260,210 filed
August 31, 1976.
This invention relates to a driving tool for a fastener and, more
particularly, to a barrel assembly for retaining fasteners in proper alignment
for driving and releasing them when driven.
In my United States patent 3,920,169, issued NovembeT 18, 1975, I
disclosed a feed mechanism and a barrel assembly for feeding a replaceable
strip of fasteners into and through the barrel assembly and a clamping means
for separating the fasteners from the strip upon impact by the driver of the
driving tool. The clamping means for separating the fastener from the strip
comprised a floating bushing positioned at the bottom end of the barrel and
which upon contac'c with the workpiece retracted upward into the barrel to en-
gage the strip prior to removal of the fastener therefrom by the driver.
While this concept has proven successful, it does present one drawback,
namely, the bushing is in a rather vulnerable location. The bushing engages
the workpiece prior to every impact and the bushing is exposed to damage from
the fastener should the fastener be out of alignment and thereby driven
against the bushing rather than through the bushing bore. The bushing is,
therefore, subjected to rough operating conditions because of its vulnerable
positioning at the end of the barrel.
In my United States patent 3,973,605, issued August 10, 1976, I
further disclosed another barrel assembly ln whlch guide fingers extended
through the barrel wall near the end thereof so as to align fasteners within
the barrel bore and thereby permit rapid and accurate installation of the
fasteners. While this invention has also proven satisfactory for most
applications, certain fastener installations present demanding torquing
conditions so that the fastener must be firmly held during its initial entry
into the workpiece. Such a fastener is the self-drilling and tapping screw
in which the fastener actually drills its own hole in sheet metal before the
tapping threads begin to engage the workpiece. Because of the high torque
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requirements of the drilling operation, the fastener tends to skid or walk
along the workpiece before penetrating and this causes the fastener to be set
out of position and may also cause a marred workpiece surface. This latter
condition is totally unacceptable in many applications such as exposed metal
siding, etc.
I have now improved upon the concepts disclosed in my earlier iden-
tified applications and I have combined those improvements into a single
barrel assembly, although either improvement can be utilized independent of
the other.
The previously referred to application 260,210 discloses and claims
an assembly for attachment to a driving tool having a driver for setting fast-
eners carried by a strip comprising: A. a sleeve adapted for attachment to the
driving tool; B. a barrel retractably mounted to the sleeve for retraction
therein and having a bore and aligned entry and exit trackways through a wall
thereof and into the bore to accommodate the strip; C. a movable bushing
having a strip engaging end and positioned within the sleeve with said end
extending into the barrel bore for slidable engagement therewith; and D.
means associating with the bushing to urge said bushing between a first
position wherein said bushing end is out of engagement with the strip and a
second position wherein the bushing end clamps the strip against the trackways
to permit the driver to extract the fastener in a setting stroke.
According to the present invention there is provided in a driver
having a barrel with a wall to define a barrel bore to accommodate fas~eners
positioned therein and driven therethrough, the improvement comprising a
carriage assembly including a sleeve slidably positioned in the barrel bore
near the end thereof and having spaced slots therethrough; means pivota]ly
connected in the slots and extending into the bore to center and hold a
fastener therein, said sleeve movable from a first position wherein the
pivotal means are rigidly held from pivoting by engagement with the barrel
wall; and a second position wherein the means are aligned with openings through
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the barrel wall to permit pivotal movement so that the fastener can pass
therethrough.
In the accompanying drawings which illustrate an exemplary embodi-
ment of the present invention:
Figure 1 is an isometric of my barrel assembly;
Figure 2 is an exploded view of my barrel assembly showing the
various components thereof;
Figure 3 is a section taken along the longitudinal axis of my
barrel assembly;
Figure 4 is an enlarged view, partly in section, through a portion
of the assembly showing the bushing in its relaxed position;
Figure 5 is an enlarged section of the bushing in Figure 4 in a
strip engaging position;
Figure 6 is an enlarged viewl partly in section, showing the carri-
age assembly in its extended position;
Figure 7 is a bottom view showing the carriage assembly; and
Figure 8 is a section taken along lines VIII-VIII of Figure 7.
My barrel assembly, generally designated 10, is adapted for attach-
ment to a standard driving tool ~not shown) of the type used to drive fasten-
ers into workpieces. These fasteners are generally of the type carried within
a plastic strip having side rails, and the strip may or may not provide a
washer for the final fastener assembly. The fasteners may be nails, screws,
or some other type which can be set by the torquing or impacting of a driver
integrally connected to the driver tool.
The various components of my barrel assembly 10 can thus be seen in
Figures 1 and 2. An internally threaded coupling 12 connects at one end to
the driver ~not shown) and at the other end to externally threaded sleeve 14.
Sleeve 14 includes a plurality (three) of parallel and equally spaced elonga-
ted slots 32 extending along its longitudinal axis. One such slot 32 includes
a connecting transverse slot 34 which, along with the slot 32, forms a bayonet
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type connection for the bushing 20 as will be described hereinafter.
Retractably operable within sleeve 14 is barrel 16 (~igures 1-3).
Barrel 16 includes a plurality of lugs 38 which connect at right angles to
barrel 16. Lugs 38 extend through the slots 32 of sleeve 14 to retain the
barrel 16 within the sleeve 14 and to be slidable along slots 32 during the
retraction of barrel 16 within sleeve 14. The barrel wall 45 of barrel 16
has extending therethrough an elongated fastener opening 40, an entry
trackway 42 in registry with the fastener opening 40 and an exit trackway 44
which is in alignment with the entry trackway 42, Figures 3 and 4. Three
relatively short, equally spaced and parallel elongated slots 46 extend
~hrough the barrel wall 45 adjacent the end thereof and carriage retention
and alignment opening 48 also extend through the barrel wall 45 near the end
thereof.
A bushing 20 is positioned with the sleeve 14, Figures 2 and 3. The
bushing 20 includes an enlarged annular head section 50 having a recess 52
therein and an elongated, annular column 56 which extends into the barrel 16.
A lift pin 54 is connected to and extends outwardly from the enlarged head
50 and rides in the slot 32 of sleeve 14 and forms the bayonet connection
with the transverse slot 34. Annular column 56 terminates in a bottom edge 58
which extends about the majority of the circular cross section of column 56.
A tang 60 formed by an extension of column 56 extends outward from the bottom
edge 58 in the area of the circular cross section which does terminate as
bottom edge 58.
A coil spring 26 is positioned at one end within the recess 52
formed in the enlarged head 50 of bushing 20 and is biased against the
driving tool (not shown) at the other end, Figures 2 and 3. A second, much
shorter coil spring 28 is positioned adjacent the bottom of enlarged head
of bushing 20 and against the ~op of barrel 16. Coil spring 26 functions
to maintain barrel 16 in an extended position. In a similar manner, coil
spring 28 functions to maintain bushing 20 in an extended position relative
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to barrel 16. The relative biasing strengths of the springs are important.
In the fully extended and relaxed position the short coil spring 28 must be
of sufficient strength to overcome the preload of the larger spring 26 so as
to space bushing head 50 from barrel 16, Figure 3. In the driving position
the larger spring 26 must be of sufficient strength to overcome the preload
of short spring 28 so as to provide the clamping function of the bushing 20
to be described hereinafter, Figure 5.
In the relaxed or extended position the bushing bottom edge 58 is
spaced slightly above or rearward of the entrance and exit trackways 42 and 44,
respectively, and the tang 60 extends into the line of travel formed by the
respective trackways. Lift pin 54 permits hand movement of the bushing 20 so
that the tang 60 can be moved completely out of the line of exit and entry
trackways and the lift pin 54 can be further moved into the transverse slot 34
so as to lock the bushing 20 out of line with the entrance and exit trackways
42 and 44, respectively to permit loading of the strip 78, Figure 1.
Carriage 22 is positioned within the free end of barrel 16, Figures 2
and 3. Carriage 22 includes three equally spaced and parallel slots 62 extend-
ing longitudinally from the one end of carriage 22 throughout most of the axial
extent thereof. Slots 62 are spaced so as to be in alignment with slots 46 of
barrel 16 and this alignment is maintained by a pin 64 which connects to and
extends outwardly from carriage 22 through single, elongated opening 48 in the
barrel wall 45. Pin 64 also retains carriage 22 within the barrel 16. Three
individual fingers 66 are respectively pivotally connected within the slots 62,
Figures 2 and 7. This pivotal comlection is made as follows. Holes 76 extend
through opposing sides of slot 62 in the carriage 22 and a pivot pin 68 extends
through the slot 76 and through a hole 70 in finger 66, Figure 2. The finger
66 includes an abutment position 72 adapted to abut and slide along the wall
45 of barrel 16. A distal portion 74 extends angularly outward from the abut-
ment portion 72 of each finger 66 and into the central bore of the annular
carriage 22, Figure 8.
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An end ring 24 is threadably mounted to the end of barrel 16 and a
coil spring 30 is positioned between annular ring 24 and the carriage 22.
Spring 30 functions to maintain carriage 22 in an extended position away from
the end of the barrel 16 so that the abutment portion 72 of each finger 66 is
rigidly positioned against the wall 45 of the barrel 16 so as to prevent rota-
tion of the fingers 66, Figures 3 and 8.
The barrel assembly is illustrated as accommodating a plurality of
fasteners 80 maintained on a strip assembly 78J which is generally plastic,
Figure 1. The strip assembly 78 is made up of a strip 88 including side rails
90 having plastic washers 94 axially spaced and held therebetween by webs 99.
Strip 88 terminates at its leading end in a tab 92 which facilitates loading.
The fasteners 80 are illustrated as having a hex fastener head 84 terminating
in a metal washer 86 adjacent the plastic washer 94. Extending through the
washer 94 is shank 82 terminating in a drill point 96.
The loading of the fastener strip assembly 78 is best illustrated in
Figures 1 and 4. The bushing 20 is hand lifted and locked through pin 54 into
transverse slot 34 so that the tang 60 is out of line with the entry and exit
trackways 42 and 44J respectively. The strip 78 is then fed through the entry
trackway 42 and out of the exit trackway 44. An initialJ elongated space 98
is provided between the first washer 94 and the tab 92. When this initial
space 98 is roughly in line with the bushing 20J the bushing is hand moved out
of transverse slot 34 and the spring 26 causes the tang 60 to drop into space
98. The tab 92 is then gripped and pulled forward by hand until the first
fastener 80 is arrested by its engagement with tang 60. Since fasteners 80 of
the type illustrated have a hex head 84, the tang 60 is dimensioned so as to
engage the round metal washer portion 86. This assures that each fastener 80
will be engaged in the same position, since engaging the hex head 84 could
result in different positions depending on the orientation of the hex head.
The tang 60 not only stops the fastener 80 but tang 60 locates the fastener 80
with respect to the bore of the barrel 16, Figure 4.
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1058429
The barrel assembly 10 is then positioned against the workpiece
(not shown) and the driving tool is pushed forward thereagainst. The barrel
16 is forceably retracted into sleeve 14 and at the same time the bushing edge
58 is forced against the rails 90 of the strip assembly 78 so as to rigidly
hold and clamp the rails 90 against the bottom surfaces of the entry and exit
trackways 42 and 44, respectively, Figure 5. In this position the strip is
locked in place with the fastener 80 in proper alignment for setting. The
socket 36 of the driver 13 engages the head 84 of the fastener 80 and continued
advancement disengages the fastener and washer 94 from the webs 99 and rails
90. The fastener 80 is then driven down the bore of the barrel 16 where it is
aligned and held by the three fingers 66 and, more particularly, the distal
portion 74 which forms an internal bore.
Further continued forward movement of the driving tool causes the
fastener 80 and more particularly the plastic washer 94 to push against the
fingers 66 and to cause the carriage 22 to move forward contracting the spring
30 when the preload of spring 30 is overcome. During this movement the fingers
66 cannot pivot since abutment portion 72 is in intimate contact with wall 45.
As the carriage 22 continues to move forward along the wall 45 of barrel 16,
the abutment portion 72 of the fingers 66 comes into registry with the slots
46 through the barrel wall 45, Figure 6. When this occurs the fingers 66 are
free to pivot about pivot pins 68 thereby permitting the fastener 80 and plas-
tic washer 94 to pass through the fingers 66 and into final driven position
into the workpiece.
It should be noted that the carriage 22 can be employed with any
barrel in which a fastener is being driven and it is not limited to the partic-
ular barrel assembly 10 illustrated herein. Carriage 22 is particularly useful
with self-drilling and tapping screws where the initial torquing of the fast-
ener meets substantial resistance as the hole is being drilled in a metal work-
piece. It is during this initial period that the fastener has a substantial
tendency to skid or walk along the workpiece surface and it is for this reason
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that the fastener must be rigidly held at this stage of the setting operation.
Once the tapping threads engage the hole, ~he fastener need not be so rigidly
held and the torquing requirements are less for the final setting operation.
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