Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
127C1 6g~
FASTENER FEEDER AND DRIVER APPARATUS
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates to a fastener
feeder and driver apparatus for use with a fastener
driving tool, and more particularly, to a new and
improved pneumatically operated feeder and driver
assembly for manipulating rotary entry fasteners,
such as screws, which are to be driven into a workpiece.
B. Descri~tion of the Prior Art
Power tools are used in a number of appli-
cations for driving threaded or rotary entry fasteners
into a workpiece. For example, drywall panels, metal
panels or the like have to be affixed to wood or metal
studs or other support elements in constructing inter-
nal walls of a building. Rotary entry fasteners,
such as screws, can be used to affix such panels to
the support elements by driving the fasteners through
the panels into the support elements. In many appli-
cations, a power screwdriver is used for driving the
screws through the panels and into the support ele-
ments. These screwdrivers may be electrically or
pneumatically powered. In either case, the power
screwdriver may include a housing with an integral
handle and a rotary driving bit extending from the
housing. In a conventional fastener driving operation,
the bit is adapted to be mated with a slot structur~
~a~
63076-lO~1
in the heacl of the fastener to be driven. As the screwdriver is
moved toward the workpiece, the end of the bit becomes disposed in
the slot structure of the screw and the screw is rotated and
driven into the ~orkpiece. In order to position the fasteners for
driving by the bi~ of the screwdriver, individual fasteners may be
manually placed against the workpiece and held there until the
screwdriver bit engages the fastener and the screw begins its
penetration into the workpiece. Alternatively, the fastener might
be held against the bit by having the driver bit magnetized.
Manual handling of individual fasteners in this manner is slow,
inconvenient and undesirable.
The assignee of record of the present applica~ion has
developed fastener feeding and driving apparatus to feed and
properly position individual fasteners so that they can be driven
into a workpiece by a power screwdriver. Two such devices are
disclosed in United States Patent Nos. 3,910,324 and 3,930,297.
The feeder mechanism disclosed in those patents are of the
mechanical type that advance a flexible strip or carrier of
fasteners from a housing containing a coiled strip of fasteners.
These feeder mechanisms rely on the force exerted by the operator
during the driving stroke to feed the fasteners and the fasteners
which are to be driven do not extend out from the workpiece
engaging surface of the nose assembly so that it is difficult to
precisely locate the fastener vis-a-vis the location, such as a
predrilled hole, on the workpiece where the fas~ener is to be
inserted.
lZ70~
63~7~-1041
SU~5l~ARY_OF THE INVENTION
The inven~ion provides an assembly for driving fasteners
into a workpiece, the fasteners being removably retained on a
carrier and having an end portion adapted to engage the workpiece,
a fastener driving means including a driver operable along a
predetermined path through a driving stroke during which one of
said fasteners is driven into the workpiece, a fastener feeding
means on said assembly for feeding individual ones of said
fasteners in sequence into said predetermined path, mechanical
fastener retaining means for releasably retaining one of said
fasteners in said predetermined path, and control means coupled to
said fastener driving means and said fastener feeding means for
effecting synchronized operation of said driver and the fastener
feeding means, said control means having cycles of operation, each
of said cycles including a first static mode during which said one
of said fasteners is releasably retained in said fastener
retaining means, a second mode during which said driver removes
said one of said fasteners from said fastener retaining means and
drives said one of said fasteners into the workpiece and a third
mode during which said fastener feeding means feeds an additiona
fastener into said predetermined path and said driver engages and
transfers said additional fastener from said carrier to said
fastener retaining means such that said control means is in said
first static mode.
An embodiment of the invention comprises a pneumatically
controlled and operated fastener feeder and driver apparatus for
supplying and positioning fasteners, such as screws having a head
1~37(~601
63076 1041
and a threaded shank portion, so that the fasteners can be driven
into a workpiece by the power screwdriver. A supply of fasteners
in strip 'orm is maintained in a magazine assembly and individual
fasteners are fed into a nose assembly of the fastener feeder and
driver apparatus. When a fastener is positioned in the nose
assembly, a portion of the threaded shank of the fastener projects
from the nose assembly so that it can be properly positioned with
respect to the workpiece into which the fastener is to be driven.
Upon actuation of the power screwdriver, a bit which engages the
fastener to be driven pushes and rotates the fastener thereby
3a
~27~6~
forcing it into the workpiece. Once the fastener has
been inserted into the workpiece to a proper depth,
pneumatically cont~olled mechanisms of the feeder and
driver apparatus moves the fastener driving tool and
thereby the bit away from the workpiece during a fire
mode and a first portion of a return mode of the feeder
and driver assembly. During a second portion of the
return mode, the fastener strip is incrementally advanced
by a pneumatically controlled feed mechanism so that a
next one of the fasteners on the s~rip is positioned with-
in the nose assembly. Thereafter the feeder and driver
mechanism moves the fastener driving tool with the bit
toward the fastener so that the fastener is removed from
the fastener strip and positioned so as to extend out
from the nose assembly for driving into the workpiece.
BRIEF DESCRIPTION OF TH~ DRAWINGS
Many other objects and advantages of the
present invention will become apparent from consider-
ing the following detailed description in conjunction
with the drawings in which:
FIG. 1 is a side view of a fastener feeder
and driver apparatus embodying the present invention;
FIG. 2 is a front view of the fastener feed-
er and driving apparatus of FIG. l;
FIG. 3 is a sectional view taken along line
3-3 of FIG. l;
FIG. 4 is a sectional view taken along line
4-4 of FIG. 3;
FIG. 5 is a sectional view taken along line
5-5 of FIG. 3;
FIG. 6 is a partial sectional view of the
fastener feeder and driver apparatus of FIG. l illus-
trating the apparatus irl its static or ready mode;
FIG. 7 is a partial sectional view of the
fastener feeder and driver apparatus of FIG. l illus-
trating the apparatus when a screw is being driven
into a workpiece;
~2~ 6~
FIG. 8 is a partial sectional view of the
fastener feeder and driver apparatus of FIG. 1 illus-
trating the apparatus when another screw is being
incrementally advanced into the nose assembly of the
fastener feeder and driver apparatus;
FIG. ~ is a schematic diagram of the air
cixcuitry for the feeder and driver mechanism portion
of the fastener feeder and driver apparatus of FIG. 1
in the static or ready mode of the fastener feeder
and driver apparatus;
FIG. 10 is a schematic diagram of the air
circuitry for the feeder and driver mechanism portion
of the fastener feeder and driver apparatus of FIG. 1
in the fire mode of the feeder and driver apparatus;
FIG. 11 is a schematic diagram of the air
circuitry for the feeder and driver mechanism portion
of the fastener feeder and driver apparatus for FIG.
1 during a first portion of the return mode of the
fastener feeder and driver apparatus; and
FIG. 12 is a schematic diagram of the air
circuitry for the feeder and driver mechanism portion
of the fastener feeder and driver apparatus of FIG.
1 during the second portion of the return mode of the
fastener feeder and driver apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now more specifically to the draw-
ings, therein is disclosed a fastener driving tool 20
having attached thereto a feeder and driver assembly
which is generally designated as 22 and which embodies
the present invention. The feeder and driver assembly
22 includes a magazine assembly 24 in which is housed
a fastener strip 26 comprised of a carrier member 28
and a plurality of fasteners 30. The fastener strip
26 is fed into a nose assembly 32 of the feeder and
driver assembly 22 wherein one of the fasteners 30,
such as a fastener 30a (FIG. 6), is positioned so
that it can be driven into a workpiece (not shown),
1;Z7C~6(~
such as a wall panel or the like. The fastener 30a is
driven into the workpiece by a driver member or bit 3
which is rotated by the fastener driving tool 20. A
pneumatically operated feeder and driver mechanism 36
forming a part of the feeder and driver assembly 22
is attached to a front end 38 of the fastener driving
tool 20 and has the nose assembly 32 mounted thereon.
~ s will be described in more detail herein-
after, the feeder and driver assembly 22 is normally
in a standby or static mode as illustrated in FIG. 6
of the drawings with a fastener 30a disposed in and
projecting from the nose assembly 32 so as to be in a
position to be driven into a workpiece~ Upon the
actuation of a trigger 40 of the fastener tool driv-
lS ing 20, the bit 34 is rotated and an operator of thetool 20 pushes the fastener driving tool 20 towards
the workpiece so that the fastener 30a is forced to
the left as illustrated in FIG. 7 of the drawings and
is driven into a workpiece. Once the fastener 3Qa is
inserted into the workpiece to a proper depth as deter-
mined by an adjustable stop screw 42, the feeder and
driver mechanism 36 moves the fastener driving tool
20 and thereby the bit 34 to the right as viewed in
FIG. 1 during a fire mode and a first portion of a
return mode of the feeder and driver assembly 22. As
a result, the bit 34 is returned to the position illus-
trated in FIG. 8 of the drawings. During a second
portion of the return mode, the fastener strip 26 is
incrementally advanced so that the next one of the
fasteners 30, such as fastener 30b, is positioned in
the nose assembly 32 as illustrated in FIG. 8 of the
drawings. Thereafter, the feeder and driver mechanism
36 moves the fastener driving tool 20 and thereby the
bit 34 toward the fastener 30b whereby the fastener
30b is removed from the fastener strip 26 and advanced
to a position illustrated in FIG. 6 with respect to
6~
the fastener 30a. The feeder and driver assembly 22
is again in its static or ready mode so that the fas-
tener 30b can be driven into a workpiece.
The fastener driving tool 20 shown in FIG.
1 is a pnuematic power screwdriver and is adapted to
drive fasteners, such as the fasteners 30, which in
the disclosed embodiment are screws, into drywall
panels and the metal or wood studs onto which such
panels are mounted. The fastener driving tool 20
includes a housing 44 from which extends a handle
portion 46. Air from a pressurized source of air,
such as a compressor, is supplied to a pnuematically
operated motor (not shown) located in the housing 44
and enables the motor to provide a rotary motion to a
bit holder 48 through a clutch 50 when the trigger 40
is depressed. While the disclosed fastener driving
tool 20 is pnuematically operated, standard electric
screwdrivers can be used as the driving tool in the
same manner as the disclosed pnuematically operated
screwdriver 20.
The front portion 38 of the fastener driv-
ing tool 20 is secured to a mounting block 52 forming
a part of the feeder and driver mechanism 36, which
mounting block 52 has an opening 54 into which the
front end 38 of the fastener driving tool 20 can be
positioned. Upon being so positioned, a retaining
screw 56 compresses the opening 54 so as to hold the
front end 38 of the fastener driving tool 20 in the
opening 54.
The feeder and driver mechanism 36 also has
a cylinder housing 58 in which is disposed pnuematic
circuitry for controlling the operation of the feeder
and driver assembly 22. As can be best seen in FIGS.
4 and 5 of the drawings, the cylinder housing 58 in-
cludes guide cylinders 60 and 62. A guide rod 64 is
movably mounted within the cylinder 60 by a bearing
66 and is attached to the mounting block 52 by a screw
7~i6~1
68. Another guide rod 70 is mounted to the mounting
block 52 by a screw 72 and moves within the cylinder
62 in the cylinder housing 58. The 4uide rods 64 and
70 aid in guiding the mounting block 52 as it moves
relative to the cylinder housing 58 during the opera-
tion of the feeder and driver mechanism 36.
The cylinder housing 58 also includes an
extend cylinder 74 in which is movably mounted an
extend piston 76 having an O-ring 78 to seal a por-
tion of the cylinder 74. The extend piston 76 isalso secured to the mounting block 52 by a screw 80.
During the fire mode and a portion of the return mode,
the extend piston 76 causes the mounting block 52 to
move to the position shown in FIGS. 4 and 5.
The feeder and driver mechanism 36 includes
a retract rod 82 which is secured to the mounting
block 52 by a screw 84. A retract piston 86 is mov-
ably mounted about the retract rod 82 and a piston
seal 88 forms a seal about the rod 82. ~ fastener 90
attached to the end of the retract rod 82 forces the
retract piston 86 to move to the right as viewed in
FIG. 5 as the retract rod 82 moves in that direction.
The retract piston 86 travels within a retract cylin-
der 92 within the cylinder housing 58. The retract
rod 82 pulls the mounting block 52 to its static posi-
tion during the second portion of the return mode.
A fastener strip feeder mechanism 94 is
disposed within the cylinder housing 58. The feeder
mechanism 94 includes a pawl cylinde. 96 which extends
vertically in the cylinder housing 58 and in which is
movably mounted a pawl piston 98. A feed pawl 100 is
mounted within the pawl piston 98. The movement of
the piston 98 within the pawl cylinder 96 is control-
led by a feed piston 102 which is movably mounted
within a feed cylinder 104. A chain link 106 is se-
cured to the feed piston 102 by a feed pin 108 and a
fastener 110. The chain link 106 is attached to a
12 706~
feed pivot plate 112 which pivots on a pivot 114 with-
in a cavity 116 in the cylinder housing 58. The pivot
plate 112 is attached to the pawl piston 98 by another
chain link 118. Since the feed piston 102 is secured
to the pawl piston 98 by means of the chain links 106
and 118 and the pivot plate 112, movement of the pis-
ton 102 from left to right in FIG. 4 translates into
an up and down motion of the piston 98 within the
feed cylinder 96. As a result, the cylinder housing
58 occupies a minimum amo~nt of space between its
front end 120 and its rear end 122 such that the en-
tire length of the feeder and driver assembly 22 is
minimized.
The cylinder housing 58 also houses a stop
valve 124 disposed within a stop valve cylinder 126.
The stop valve 124 is actuated by the stop screw 42
and controls the extent to which the mounting block
52 moves towards the front end 120 of the cylinder
housing 58 while one of the fasteners 30 is being
driven into a workpiece.
The cylinder housing 58 in addition has a
channel 128 through which the driver bit 34 extends
(FIG. 5). The driver bit 34 is held in the bit holder
48. A spring 130 is disposed about the bit holder 48
between the cylinder housing 58 and the mounting block
52. The spring 130 is compressed as the mounting
block 52 is moved towards the front end 120 of the
cylinder housing 58 during the installation of one of
the fasteners 30 and assists in returning the mount-
ing block 52 to the position shown in FIGS. 4 and 5of the drawings during the fire mode and the first
portion of the return mode.
A cover plate 132 is secured to the rear
end 122 of the cylinder housing 58 by fasteners 134
and 136. In order that personnel are not exposed
during the operation of the fastener feeder and driver
assembly 22 to the rods 64 and 70, the pistons 82 and
i27(}6~1
76 and the bit holder 48, the feeder and driver
assembly 22 includes a guard 138 which is attached to
the mounting block 52 by sGrews 140 and 142 and moves
about the cylinder housing 58 when the mounting block
52 moves relative to the cylinder housing 58 during
the operation of the feeder and driver assembly 22.
The magazine assembly 24 is maintained rela-
tive to the driving tool 20 by securing it to the
mounting block 52 by means of a downwardly projecting
0 leg 144 which is secured to the mounting block 52 by
a fastener 146. The leg 1~4 is attached to a socket
148 projecting from a housing 150 of the magazine
assembly 24. The housing 150 preferably is formed of
a relatively lightweight, yet strong material such as
a suitable plastic or the like. The housing 150 is
generally circular in outline so that it can receive
the fastener strip 26 when it is rolled into a coil.
In this connection, a lower peripheral wall 152 of
the housing 150 may be swung about a hinge 154 and is
2 latched in a closed position by a latch assembly 156.
When the latch 156 is released, the door 152 can be
swung about the hinge 154 so that the inner part of
the housing 150 is accessible and can be filled with
a coiled fastener strip 26. When the door 152 is
again secured in its closed position as shown in FIG.
1 of the drawings, a portion of the fastener strip 26
is fed out of the housing 150 to the nose assembly
32. The portion of the fastener strip 26 extending
between the housing 150 and ~he nose assembly 32 is
twisted through a substantial angle so that there is
no interference between the fastener strip 26 and a
workpiece and the fastener strip 26 can flex as the
driving tool 20 and the magazine assembly 24 moves
relative to the nose assembly 32.
As illustrated in connection with fasteners
30a, 30b and 30Cr each fastener 30 includes a shank
portion 158, at least a portion of which is threaded,
~Z7Q6(~1
11
a tip 160 at the entry end of the shank portion 158
and a head 162 at the opposite end of the shank lS8.
The head 162 is provided with a drive slot structure
which is complementary to a tip portion 164 of the
driver bit 34. When the tip portion 164 of the bit
34 is inserted into the complementary drive slot of
the head 162, the rotation of the driver bit 34 causes
the fastener 30 to be rotated in accordance with known
practices.
The fastener strip 26 is of the type dis-
closed in United States Patent No. 3,885,669, assign-
ed to the assignee of record of the present applica-
tion. The fastener strip 26 includes the carrier
member 28 which is in the form of an elongated strip
of flexible plastic material. The carrier member 28
is continuous throughout the length of the fastener
strip 26 and, as illustrated in connection with the
fastener 30c in Fig. 1, includes a tab 166 which ex-
tends from one side of the carrier strip 28 and which
is designed to receive the fastener 30c in a slot
located in the tab 166 such that the fastener 30c i5
frictionally retained therein with the shank portion
158 of the fastener 30c extending generally parallel
to the plane of the carrier member 28. The fastener
strip 26 can be provided with a tab extending from
the other end of the carrier member 28 in order that
the fasteners 30 are more securely affixed to the
fastener strip 26. The carrier member 28 also is
provided with a series of openings 168, one of which
openings is longitudinally placed along the carrier
member 28 between each of the tabs 166. The openings
168 are adapted to receive the feed pawl 100 in order
for the fastener strip 26 to be incrementally advanced
during the operation of the feeder and driver assembly
22.
As previously indicated, the feeder and
driver mechanism 36 which forms a part of the feeder
127&6~1
12
and driver assembly 22 is a pneumatically operated
mechanism. Pressurized air from an air reservoir~
such as a compressor or the like, is supplied to a
port 170 on the lower portion of the cylinder housing
58 via an appropriate hose or the like (not shown).
The operation of the pneumatically operated feeder
and driver mechanism 36 will become more apparent
with reference to FIGS. 9-12 which disclose in schema-
tic form the pneumatic circuitry for the feeder and
driver mechanism 36 during various modes or phases of
the operation of the feeder and driver assembly 22.
More specifically, and with reference to
FIG. 9 of the drawings, the feeder and driver assembly
22 is shown therein in its static or ready mode so
that one of the fasteners, such as the fastener 30a
shown in FIG. 6, is ready for being driven into a
workpiece. In this regard, the fastener 30a is held
in a nose chuck 172 consisting of jaws 174 and 176.
The jaws 174 and 176 are biased to hold the fastener
30a as shown in FIG. 6 so that the fastener 30a has a
portion of its shank 158 extending out from a nose
guard 178. When the feeder and driver assembly 22 is
in the static mode disclosed in FIGS. 6 and 9 of the
drawings, the bit 34 has its tip portion 164 inserted
into the head 162 of the fastener 30a. Advantageously,
since the top 160 of the fastener 30a extends out
from the workpiece engaging surface of the nose guard
178 prior to being driven into a workpiece, the fas-
tener 30a may be positioned within a pilot hole in
the workpiece into which it is to be driven or against
the workpiece, if no pilot hole is formed therein,
prior to the fastener 30a being rotated and driven by
the bit 34. It is noted that when the fastener 30a
has been positioned as shown in FIG. 6, the fastener
30a has been removed from the fastener strip 26 as
will be discussed in more-detail below.
6~
13
When the feeder and driven assembly 22 is
in its static mode as illustrated schematically in
FIG. 9, reservoir air (i.e., pressurized air) is sup-
plied through an air duct 180 to the portion of the
cylinder 104 between an O-ring 182 sealing the cylin-
der 104 and O-ring 184 on the feed piston 102. The
reservoir air is also supplied through a duct 186 to
the portion of the cylinder 126 between O-rings 188
and 190 on the stop valve 124 and from there through
another duct 192 to the portion of the feed cylinder
104 between an O-ring 194 on the feed piston 102 and
an O-ring 195 which seals the cylinder 104 along the
cover plate 132. That portion of the feed cylinder
104 is connected via a duct 196 to the retract cylin-
der 92 so that reservoir air is supplied to the re-
tract cylinder 92 between the piston seal 88 and the
retract piston 86.
Air vents 198, 200, and 202 are provided in
the cylinder housing 58 to connect various portions
of the pneumatic circuitry to atmosphere. In the
static mode illustrated in FIG. 9, the air vent 198
vents that portion of the stop valve cylinder 126
between the O-ring 190 and an O-ring 204 to atmosphere.
Since that portion of the stop valve cylinder 126
between the O-rings 190 and 204 is connected to the
extend cylinder 74 by a duct 206, the portion of the
extend cylinder 74 to the left, as viewed in FIG. 9,
of the O-ring 78 on the extend piston 76 is at atmo-
spheric pressure. The air vent 200 connects the por-
tion of the stop valve cylinder 126 to the left, as
viewed in FIG. 9, of the O-ring 188 to atmosphere. A
duct 208 connects that portion of the stop valve
cylinder 126 and therefore the vent 200 to the por-
tion of the extend cylinder 74 to the right of the o-
ring 78. Consequently, the en~ire extend piston
cylinder 74 is at atmospheric pressure. The air vent
202 is coupled to the feed piston cylinder 104 between
6~1
14
the O-rings 184 and 194 resulting in that portion of
the piston cylinder 104 being maintained at atmospheric
pressure.
In the static mode, the retract rod 82 posi-
S tions the mounting block 52 as illustrated in FIG. 9
of the drawings due to the fact that reservoir air
supplied to the cylinder 92 forces the retract piston
86 against a spacer 210. In addition, the feed piston
102 positions the pawl piston 98 and consequently the
feed pawl 100 in the position shown in FIG. 9 such
that one of the fasteners 30 will be in alignment
with the driver bit 34. The feed piston 102 is placed
in this position due to the fact that reservoir air
supplied to the larger diameter of the feed piston
102 between the O-rings 194 and 195 overcomes the
force exerted by the reservoir air that is supplied
to the smaller diameter portion of the feed piston
102 between the O-rings 182 and 184. Since the entire
extend cylinder 74 is vented to atmosphere, the extend
piston 76 is allowed to move within the cylinder 74
as the mounting block 52 is moved to the left in FIG.
9 by the retract piston 82. The stop valve 24 is in
its ready mode as shown in FIG. 9 due to the presence
of reservoir air between the O-rings 188 and 190.
When the feeder and driver assembly 22 is
in its static mode, an operator can drive a fastener,
such as the fastener 30a shown in FIG. 6, into a work-
piece. This is accomplished by the operator actuating
the trigger 40 so that the fastener driver tool 20
rotates the bit holder 48 which in turn causes the
driver bit 3~ to rotate. The operator then pushes
against the handle 46 of the fastener driving tool 22
causing the mounting block 52 to move toward the work-
piece. This movement of the mounting block 52 forces
the bit holder 48 and the bit 34 to push against the
fastener 30a and the fastener 30a is thereby installed
into the workpiece. During this process, the fastener
127~6~1
30a forces open the jaws 174 and 176 of the nose chuck
172 as illustrated in FIG. 7 of the drawings. Once
the fastener 30a has been driven into the workpiece
an appropriate distance, an end 212 of the stop screw
42 engages a stem 214 of the stop valve 24 projecting
through the cover plate 132. As a result, the stop
valve 24 is moved to the position shown in FIG. 10 of
the drawings initiating what can be termed the fire
mode of the feeder and driver assembly 22.
The stop screw 42 can be adjusted relative
to the mounting block 52 and locked in place by a
lock nut 216. Consequently, the stop valve 124 acts
as a depth control to determine the depth to which
one of the fasteners 30 will be driven into a work-
piece. More specifically, the location of the mount-
ing block 52 when the fire mode is initiated as illus-
trated in FIG. 10 of the drawings determines the ex-
tent to which the bit 34 has driven a fastener, such
as the fastener 30a in F~G. 7, out from the nose
assembly 32 into a workpiece. If the stop screw 42
is adjusted so that the end 212 of the stop screw 42
is further to the left as viewed in FIG. 9, the end
212 will engage the stem 214 when the mounting block
52 is further to the right as viewed in FIG. 9. In
this event, the fasteners 30 being driven into a work-
piece will not be driven into the workpiece as deep
as when the stop screw 42 is adjusted so that the tip
212 of the stop screw 42 is further to the right as
viewed in FIG. 9.
When the stop valve 124 is moved towards
the position shown in FIG. 10 of the drawing, the O-
ring 188 passes the air vent 200 such that the duct
192 is vented to atmosphere resulting in the venting
to atmosphere of the portion of the feed cylinder 104
between the O-ring 194 and the piston seal 195. Since
reservoir air is still supplied through the duct 180
to the feed piston 104 between the O-rings 182 and
6~
16
184, the feed piston 102 will move in the direction
indicated by the arrows in FIG. 10 of the drawings.
This movement of the feed piston 102 causes the feed
pivot plate 112 to pLvot about the pivot 114 pulling,
via the chain link 118, the pawl piston 98 downwardly,
as viewed in FIG. 10, in the feed cylinder 96. When
the pawl piston 98 moves in this manner, the feed
pawl 100 moves downwardly as viewed in FIGS. 1 and 10
along the carrier member 28 of the fastener strip 26
that is held against the feed pawl 100 in the nose
assembly 32. However, since the feed pawl 100 has a
cam surface 218 which permits the pawl 100 to slip
past the opening 168 in the carrier member 28 when
the feed piston 98 is moved as illustrated in FIG.
10, the feed pawl 100 does no~ move the fastener strip
26.
As the feed piston 102 moves to the right
as viewed in FIG. 10, the O-ring 194 passes the air
duct 196 so that the air duct 196 becomes vented to
atmosphere because it is now connected to the air
vent 202. Consequently, the retract cylinder 92 be-
tween the retract piston 86 and the piston seal 88 is
placed at atmospheric pressure so that the retract
piston 86 can be moved towards the piston seal 88.
The movement of the stop valve 124 also results in
the movement of the O-ring 190 past the duct 186 so
that reservoir air is now supplied to the stop valve
cylinder 126 between the O-rings 190 and 204. Reser-
voir air is also supplied via duct 206 to the extend
cylinder 74 to the left of O-ring 78 as viewed in
FIG. 10~ Since the extend cylinder 74 to the right
of the O-ring 78 is maintained at atmospheric pres-
sure, via an opening in the cover plate 132 about the
extend cylinder 74, the extend piston 76 is forced to
the right as viewed in FIG. 10 of the drawings. The
movement of the extend piston 76 in this manner forces
the mounting block 52 to the right as viewed in FIG.
6(~i
17
10. This movement of the mounting block 52 is guided
by the guide rods 64 and 70.
~ he mounting block 52 continues to move to
the right. FIG. 11 of the drawings schematically
illustrates the feeder and driver mechanism 36 at a
point in time during what can be termed a first por-
tion of the return mode of the feeder and driver
assembly 22. During this portion of the return mode,
reservoir air continues to be supplied to the extend
cylinder 74 forcing the extend piston 76 further to
the right as viewed in FIG. 11. As the mounting block
52 moves to the right as viewed in FIG . 11, the fas-
tener 90 on the retract rod 82 engages the retract
piston 86 and moves it away from the spacer 210 so as
to move it toward the piston seal 88 as illustrated
in FIG. 11 of the drawings. During this portion of
the return mode of the feeder and driver assembly 22,
the feed piston 102 is maintained in the position
shown in FIG. 11 so that the feed pawl 100 is in its
lowered position illustrated in FIG. 11 and is in
alignment with the next one of the openings 168 in
the carrier member 28 of the fastener strip 26 so
that it will be in a position to incrementally
advance the carrier member 28 when the feeder and
driver assembly 22 enters the second portion of its
return mode. The stop valve 124 remains in its
depressed or actuated position due to the fact that
reservoir air continues to be supplied to the stop
valve cylinder 126 between O-rings 190 and 204 and
the remaining portions of the stop valve cylinder 126
are maintained at atmospheric pressure. It is noted
that at the point in time during the return mode illus-
trated in FIG. 11, the O-ring 78 on the extend piston
76 is still to the left of the duct 208. As the ex-
tend piston 76 is forced further to thç right as view-
ed in FIG. 11, the O-ring 78 will move past the duct
208 resulting in the feeder and driver assembly 22
~27~6~
transferring into the second portion of its return
mode.
As the e~tend piston 76 moves to the right
as viewed in FIGS. 11 and 12 of the drawings and the
O-ring 78 passes the duc~ 208, reservoir air in the
extend cylinder 74 is communicated via duct 208 to
the portion of the stop valve cylinder 126 to the
left of O-ring 188. The stop valve 124 is thereby
forced toward the right in FIG. 12 to its ready posi-
tion illustrated in FIG. 12. When the stop valve 124
has been so moved, the portion of the stop valve
cylinder 126 to the left of O-ring 188 is vented to
atmosphere because it is now in communication with
the air vent 200. In addition, the portion of the
extend cylinder 74 to the left of the O-ring 78 is
also vented to atmosphere because it is coupled to
the air vent 200 through the lefthand portion of the
stop valve cylinder 126 and the duct 208. Since no
reservoir air is supplied to the extend cylinder 74,
the extend piston 76 will cease moving to the right
as viewed in FIG. 12 such that the mounting block 52
no longer will be moved in that direction. At this
point in time, the bit holder 130 has also been re-
tracted to the right in FIG. 12 so that the bit 34 is
positioned as illustrated in FIG. 8 of the drawings.
Once the stop valve 124 is returned to its
ready position illustrated in FIG. 12, reservoir air
that is being supplied via the duct 186 to the stop
valve cylinder 126 between the O-ring 188 and 190 is
now supplied to the duct 192 because the duct 186 is
now in communication with the portion of the stop
valve cyl.inder 126 between the O-rings 188 and 190.
Consequently, reservoir air is supplied to the feed
piston cylinder 104 between the O-rings 194 and 195.
Since the feed piston 102 has a larger diameter in
3 the area of the O-ring 194 as compared to the diameter
of the feed piston between the O-rings 182 and 184,
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19
the feed piston 104 is forced to move to the left as
viewed in FIG. 12 of the drawings. This results in
the movement of the feed assembly 94 such that the
pivot plate 112 is pivoted about the pivot 114 as
shown by the arrow on the pivot plate 112 in FIG. 12.
The feed piston 98 moves upwardly in the feed cylinder
96 so that feed pawl 100 also is moved upwardly in
FIG. 12 to the position shown in FIG. 12. The move-
ment of the feed pawl 100 in this manner results in
the cam surface 218 engaging one of the openings 168
in the carrier member 28 of the fastener strip 26 and
the fastener strip 26 is incrementally advanced up-
wardly as viewed in FIG. 1 of the drawings. The incre-
mental advance of the fastener strip 26 in this manner
results in the next one of the fasteners 30 to be
positioned in alignment with the bit 34 as illustrated
in FIG. 8 of the drawing.
As the feed piston 104 is moved in this
manner, the O-ring 194 passes the duct 196 and reser-
voir air is supplied from the feed cylinder 104 through
the duct 196 to the retract cylinder 92 between the
retract piston 86 and the piston seal 88. The supply-
ing of reservoir air to the retract cylinder 92 in
this manner forces the retract piston 86 to move to
the left as viewed in FIG. 12 and the retract piston
86 engages the fastener 90 forcing the retract rod 82
to also move towards the left as viewed in FIG. 12 of
the drawing. Movement of the retract rod 82 forces
the mounting block 52 to also move to the left as
viewed in FIG. 12.
The movement of the mounting block 52 is
not inhibited by the extend piston 76 because the
extend cylinder 74 is maintained at atmospheric pres-
sure since the air vent 198 is now coupled to the
leEthand portion of the extend cylinder 74 through
the duct 206. As the mounting block 52 moves to the
left in FIG. 12 toward its static or ready position
~;27(~
as illustrated in FIG. 9 of the drawings~ the blt
holder 130 and therefore the bit 34 are moved toward
the fastener 30b as shown in FIG. 8 which has been
positioned in the nose assembly 32 in alignment with
the bit 34 by the incremental advance of the carrier
member 28 of the fastener strip 26 due to the movement
of the feed pawl 100.
The mounting block 52 will proceed to move
toward the rear end 122 of the cylinder housing 58
due to the continued supplying of reservoir air to
the retract cylinder 92 between the retract piston 86
and the piston seal 88. The mounting block 52 will
come to its static or ready position as lllus~rated
in FIG. 9 when the retract piston 86 engages the spacer
210. Prior to the mounting block 52 being positioned
as illustrated in FIG. 9 of the drawings, the tip 164
of the bit 34 will engage the head 162 of the fastener
30b forcing the fastener 30b be removed from the slot
in the tab 166 on the carrier member 28 in which the
fastener 30b is held. The fastener 30b is then forced
between the nose jaws 174 and 176 until it reaches
the position illustrated in connection with the
fastener 30a in FIG. 6 of the drawings. The bit 34
and the fastener 30b will be positioned as shown in
FIG. 6 when the mounting block 52 is positioned as
shown in FIG. 9 with the retract piston 86 against
the spacer 210. ~t this point in the operation of
the feeder and driver assembly 22, the feeder and
driver assembly 22 is now in its static or ready posi-
tion to again be actuated by an operator installing
the next screw 30b into a workpiece.
Since the fastener driving tool 20 and the
feeder and driver mechanism 36 can be operated by
pressurized air supplied by a portable compressor or
the like, the feeder and driver assembly 22 can be
utilized at a construction sight or any other location
where a source of pressurized air is available. More-
lZ~
21
over, the feeder and driver assembly 22 can be maderelatively lightweight and not cumbersome as compared
to a mechanism which would require an electric motor
or the like to operate the feeder and driver mechanism.
Although the present invention has been
described with reference to one preferred embodiment
thereof, it will be apparent that other modifications
and embodiments can be devised by those skilled in
the art which will fall within the spirt and scope of
the present invention.
