Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02325790 2000-11-14
WIRE PULLER
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to the field of an apparatus for applying pulling
force.
More specifically the invention relates to an apparatus for placement of
conductive wire.
2. Background Art
Supplying buildings with electricity and communications involves threading
lines,
or cable, through conduit. Typically, the path that cable must travel through
conduit
includes changes in elevation and turns around corners. Generally, the
procedure used to
run cable involves first threading lightweight flexible lines through the
entire length of
conduit. Heavier lines are then pulled through, by attaching them to one end
of the
lighter line and pulling the lighter line through at the other end of the
conduit. This
procedure may need to be repeated until a line is threaded which can bear the
weight of
the target cable, when is then attached and pulled through.
To thread heavier lines, lighter lines must be pulled through first. The
pulling
force required can be significant depending on the weight of the heavier lines
and
distance traveled. The pulling force can also increase with the bends and
turns in the
conduit. Thus, there is a need to substitute machine force for human force to
reduce the
human effort required in this procedure.
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Others have substituted machine force for human force in pulling cable through
conduit. Oleson, U.S. Patent 3,190,616, discloses a cable threading apparatus.
Newell,
U.S. Patent 3,968,952, discloses an assembly for pulling a line. Straight,
U.S. Patent
4,270,734, discloses a portable wire puller. Lucas, U.S. Patent 4,456,225
discloses a
cable pulling apparatus. Carter et al., U.S. Patent 4,497,470, discloses a
powered cart
mounted cable puller.
Each of the named apparatus includes a dedicated motor; however, dedicating a
motor in most cases adds bulk, weight, and cost. Therefore, the need to
substitute
machine force for human force in pulling wire without significant bulk,
weight, and cost
is not met by these apparatus.
Others have applied the use of hand-held power drills for winding. Cole, U.S.
Patent 4,196,864 discloses a line winding tool set. Sossamon, U.S. Patent
4,951,890
discloses a drill-operated adapter for unwinding fishing lines from reels.
Jones, U.S.
Patent 5,149,056 discloses a wire puller for electrical conduits.
These apparatus attach to a power drill, utilizing the power of the drill to
pull
cable and wind it onto various sized and shaped spindles. However, they are
often
insufficient for use with the various weights and lengths of cable threaded
through
conduit. Further, these apparatus share a problem, in that an operator must
exert differing
degrees of stabilizing force to hold the drill during the winding process. In
summary, the
prior art apparatus have proven to be cumbersome, and to be very limited in
the capacity
of line that may be wound onto their spindles.
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DISCLOSURE OF INVENTION
Thus, it can be seen from the above discussion that it would be an improvement
in
the art to provide a line puller which can be driven by a multiple use motor
so that the
weight and cost of the apparatus is minimized. Also it would be an improvement
if the
line puller could be positioned such that the operator does not have to exert
a stabilizing
force while the wire is pulled, and is not limited in line winding capacity.
According to the present invention, an apparatus for pulling line through
conduit
is disclosed, to which a power drill or other portable power tool may be
attached as the
motor force. The apparatus includes a frame having a drive shaft mounting
portion and a
power tool restraint portion, wherein the power tool restraint portion is
adapted to register
a portable rotary power tool, such as a power drill, with the frame. A drive
shaft is
mounted with the frame in the drive shaft mounting portion, wherein the drive
shaft may
be rotated about its longitudinal axis and a first end of the drive shaft is
sized to be
coupled with a rotary output of the power tool. A frame switch having an "off'
position
and an "on" position is also mounted on the frame, the frame switch engaging a
power
switch on the power tool when the frame switch is moved from the "off'
position to the
"on" position and when such a tool is mounted in the restraint portion and
coupled to the
drive shaft. The stand and frame can be disassembled for easy transport.
The wire pulling apparatus is located near a conduit opening, or junction box,
through which the line is to be pulled. The power tool is positioned onto the
wire pulling
apparatus. For example, if the power tool is a power drill it is positioned
such that the
jaws of the drill fit around one end of the drive shaft, and such that the
frame switch can
be used to depress the trigger switch on the drill. The chuck of the drill is
used to couple
the drill jaws to the drive shaft. The drill switch lever of the frame switch
is rotated to
actuate the drill that turns the drive shaft. The line to be pulled is then
wrapped at least
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once around a spool attached to the drive shaft and maintained taut by the
wire puller
operator, to allow the turning of the drive shaft to pull the line through the
conduit and
out of the junction box.
The foregoing and other features and advantages of the present invention will
be
apparent from the following more particular description of preferred
embodiments of the
invention, as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
Preferred embodiments of the present invention will hereinafter be described
in
conjunction with the appended drawings, where like designations denote like
elements,
and:
FIG. 1 is a side plan view of an embodiment of the present invention;
FIG. 2 is a top plan view of an embodiment of the present invention; and
FIG. 3 is a top plan view depicting the operation of an embodiment of the
present
invention.
FIG. 4 is a partially broken away front plan view of a wire puller according
to the
present invention.
FIG. 5 is a partially broken away side plan view of the wire puller of FIG. 4.
FIG. 6 is an isometric view of the wire puller of FIG. 4 including a stand for
supporting the forearm portion of the frame.
FIG. 7 is an isometric view of a mounting bracket attached to the wire puller
of
FIG. 4.
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BEST MODES FOR CARRYING OUT THE INVENTION
According to an embodiment of the present invention, a wire puller that
utilizes
the motor force of a standard right-angle power drill is disclosed. However,
those skilled
in the art will appreciate that any of several portable rotary power tools,
such as power
wrenches, can be used with the present invention. The wire puller can be
operated by a
single operator and disassembled to fit into a hand-held case. The hand-held
case for the
embodiment shown in FIGs. 1-3, measuring approximately 12 inches wide, by 21
inches
long, by 7 inches high, facilitates transport of the wire puller to a location
where line is to
be pulled. A typical location at which line is pulled is a junction box at the
end of a
length of conduit. The wire puller is assembled in close proximity to the
junction box.
Assembly of the wire puller shown in FIGs. 1-3 includes the steps of attaching
the
wire puller frame to its stand, resting the forearm frame portion of the wire
puller on the
junction box opening, positioning the power drill such that one end of the
wire puller
drive shaft fits into the jaws of the drill, and such that the trigger switch
of the power drill
can be depressed by rotating the wire puller drill switch lever, and
tightening the power
drill chuck over the drive shaft. Thus, the only attachment of the power drill
to the wire
puller is the drill jaw to drive shaft coupling. This sole point of attachment
allows the
power drill to be easily detached from the wire puller, when needed for other
drill uses.
Operating the assembled wire puller with attached power drill requires only a
single operator. Operation does not require the wire puller operator to hold
the power
drill, because the attached drill is tightly coupled to the drive shaft and
supported by the
wire puller frame. Nor does operating the wire puller require the operator to
depress the
drill trigger switch to start and stop line pulling. Instead, the operator
controls the starting
and stopping of the line pulling by grasping and releasing a taut hold on the
line.
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To operate the wire puller, the operator first actuates the power drill, by
rotating
the drill switch lever on the wire puller. When the drill is actuated, the
drive shaft and
attached spool rotate. To pull line, the operator wraps the line to be pulled
around the
rotating spool, for at least one revolution. The wrapping creates a frictional
coupling of
the spool to the line, which allows the rotating spool to pull the line. As
long as the wire
puller operator keeps the line taut against the rotating spool, the wire
puller pulls line. To
stop pulling line, the wire puller operator need only relax the grip on the
line, to stop the
frictional coupling between the spool and the line. Thus, after initial
actuation of the
drill, line pulling can be started and stopped without starting and stopping
the drill.
Thus, the disclosed wire puller is easy to transport, assemble, and operate. A
standard right-angle drill fits easily onto the wire puller to provide the
motor force to pull
line. Only a single operator is needed to operate the wire puller. The
operator need not
hold the drill, nor control line pulling from the trigger switch on the drill.
Instead, once
the drill is actuated, the operator need only keep the line taut on the
rotating spool to start
line pulling, and relax the line to stop line pulling. And while the wire
puller is not
operational, the drill can easily be detached from the wire puller to serve
other drill uses.
Referring now to FIG. 1, a side view of an embodiment of the present invention
is
depicted. Wire puller 100 includes a stand 180 and a frame 170. Stand 180
includes a
base 190, a series of hollow square tubes 188 and 184, and a series of pins
176 and 186.
Those skilled in the art will recognize that stand 180 can include any number
of pieces
which together stabilize frame assembly 170.
Base 190 rests on a floor, or surface, of the location where the line is to be
pulled.
The top of base 190 contains a sleeve, shaped to receive square tube 188.
Square tube
188 is hollow to slidably receive square sleeve 184. Square sleeves 188 and
184 have a
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series of matched sets of holes on opposite sides. The holes are suitably
sized and spaced
to allow square sleeves 188 and 184 to be fastened together by pin 186 at
differing
heights. Those skilled in the art will recognize that a number of types of
adjustable
height mechanisms can be used in place of two hollow square sleeves fastened
together
with pins for this and other embodiments described herein.
Square sleeve 184 is attached to frame assembly 170 via pivot bracket 175 and
pin
176. Sufficient clearance is necessary between square tube 184 and pivot
bracket 175 to
allow frame assembly 170 to rotate such that forearm frame portion 150 can
tilt
downward or upward from the top of square sleeve 184. Thus, attaching the
stand to
frame assembly 170 prevents movement of the frame assembly in any direction
other
than that of the pivot. Pin 176 is inserted through one side of pivot bracket
175, through
square tube 184, and then through the second side of pivot bracket 175.
Forearm frame
portion 150 is configured to be able to rest on the edge of ajunction box. In
this manner,
the wire puller stand provides one leg of horizontal support for frame
assembly 170, and
the junction box (not shown) provides a second leg of horizontal support.
Frame assembly 170 suitably includes a forearm frame portion 150, a drive
shaft
mounting frame portion 210 (shown in FIG. 2), and a drill restraint frame
portion 140.
Forearm frame portion 150 includes a narrow arm-like extension of frame
assembly 170
and spool 160. The drive shaft mounting frame portion includes a drive shaft
130, a
housing 120, and a spool 110. Drill restraint frame portion 140 includes a
bracket 142 for
holding a standard right-angle drill against frame assembly 170, and a frame
switch
including a drill switch lever 145 having a drill switch actuator 147.
Although the frame
switch preferably includes drill switch lever 145, the frame switch can be any
of various
other switch configurations, such as a sliding switch. Those skilled in the
art will
recognize that frame assembly 170 can take many shapes to serve the functions
of the
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present invention. Those skilled in the art will also recognize that although
drill restraint
frame portion 140 has been adapted for a standard right-angle drill, drill
restraint frame
portion 140 can be adapted for various sizes and shapes of drills.
Spool 160 is mounted on the narrow arm-like extension of frame assembly 170.
When positioned a short distance into the junction box, spool 160 facilitates
the pulling
of the line by guiding the line towards spool 110. For instance, conduit
connecting to a
junction box typically runs from a direction other than perpendicular to the
opening of the
junction box. By running the line over spool 160, the line is guided from the
direction it
travels through the conduit, towards spool 110, which is a direction more or
less
perpendicular to the opening of the junction box. Thus, spool 160 minimizes
any friction
created by the pulling of the line out from the junction box.
Drive shaft 130 is the sole attachment for the power drill, and rotates to
effect the
pulling of line. Drive shaft end 132 is sized to receive the jaws of the power
drill. Drive
shaft 130 runs through housing 120 which suitably contains bearings to
facilitate the
rotating of drive shaft 130 around its longitudinal axis. Housing 120 is
mounted on frame
assembly 170. Spool 110 is mounted on drive shaft 130, on the end opposite of
drive
shaft end 132, where the power drill attaches. When at least one revolution of
line is
placed around spool 110, the turning of drive shaft 130 pulls the line through
the conduit.
Drill restraint frame portion 140 is designed to allow drill switch lever 145
to
actuate the drill, when the drill has been coupled to drive shaft end 132.
Bracket 142 is
mounted on frame assembly 170. Bracket 142 serves to prevent the power drill
from
spinning around drive shaft 130 during actuation, when the jaws of the power
drill are
coupled with drive shaft end 132. Drill switch lever 145 is attached both to
bracket 142
and frame assembly 170. Rotating drill switch lever 145 ninety degrees serves
to depress
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the drill trigger and thus actuates the power drill, when the drill is coupled
to drive shaft
end 132 and held within bracket 142.
Referring now to FIG. 2, a top view of the assembled wire puller according to
an
embodiment of the present invention is depicted. The three portions of frame
assembly
170 are all clearly visible, namely: forearm frame portion 150, drive shaft
mounting
frame portion 210, and drill restraint frame portion 140.
FIG. 2 shows how the narrow arm of frame assembly 170 extends outwardly and
is suitable to be placed into a junction box. When forearm frame portion 150
is
positioned to rest on the edge of a junction box, spool 160 serves to minimize
any drag
friction created by pulling the line out from the junction box towards spool I
10.
FIG. 2 shows drill switch lever 145 in the "off' position, that is, the
position in
which drill switch actuator 147 will not actuate the power drill. The wire
puller operator
rotates drill switch lever 145 to rotate drill switch actuator 147 to actuate
and to shut off
the power drill, once the power drill is coupled to drive shaft end 132 and
held between
bracket 142 and frame assembly 170.
Referring now to FIG. 3, a top view according to an embodiment of the present
invention is depicted. Power drill 320 is preferably a standard right-angle
drill, and is
positioned such that power drill jaws 328 receive drive shaft end 132. Power
drill handle
322 fits between bracket 142 and frame assembly 170. Power drill chuck 326
tightens to
couple power drill jaws 328 to drive shaft end 132. The drill jaw to drive
shaft coupling
is the only attachment of power dri11320 to the wire puller.
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FIG. 3 shows the wire puller in operation. Drill switch lever 145 and drill
switch
actuator 147 are in the "on" position, thus depressing power drill trigger
switch 324 and
actuating power drill 320. Actuating power drill 320 rotates drive shaft 130
and spool
110. The wire puller operator wraps line 310 around spool 110 for at least one
revolution. The wire puller operator then holds line 310 taut to establish
frictional
coupling between spool 160 and line 310. As the wire puller pulls line 320 out
of the
junction box, the wire puller operator accepts the feed to maintain the
frictional coupling
of line 320 and spool 110. The wire puller operates to pull line while the
power drill is
actuated and the line is frictionally coupled to spool 110. To cease pulling
line 310, the
operator need only release the grip on line 310 to stop the frictional
coupling between
spool 110 and line 310. Thus, line pulling can start and stop without the need
to rotate
drill switch lever 145, after initial actuation of power dril1320.
In summary, the wire puller apparatus is easily assembled from pieces which
fit
into a hand-held case, measuring approximately 12 inches wide, by 21 inches
long, by 7
inches high. The wire puller is assembled and optimally positioned in close
proximity to
a junction box or other location, from which the line is to be pulled. Forearm
frame
portion 150 suitably rests on the edge of an electrical junction box. Spool
160 in forearm
frame portion 150 extends into the junction box and serves to minimize the
friction
created by pulling the line out of the junction box. Drive shaft end 132 is
sized to be
received within power drill jaws 328. Power drill 320 is positioned in drill
restraint
frame portion 140 to receive drive shaft end 132 and to allow drill switch
lever 145 and
drill switch actuator 147 to actuate power dril1320. Power drill chuck 326
couples power
drill 320 to drive shaft end 132.
To operate the wire puller, the operator actuates power dri11320 by rotating
drill
switch lever 145. When power drill 320 is in operation, it tums drive shaft
130 and spool
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110. The operator runs line 310 over spool 160, towards spool I 10. The
operator then
wraps line 310 around spool 110 for at least one revolution, to establish a
frictional
coupling between spool 160 and line 310. As long as the operator maintains a
taut hold
of line 310, line 310 will be pulled out of the junction box. To cease pulling
line 310 or
reduce the speed with which the line is being pulled, the operator need only
lessen the
grip on line 310 to reduce or disengage the frictional coupling between spool
110 and line
310. Thus, line pulling can start and stop without the need to rotate drill
switch lever
145, after initial actuation of power dri11320, and perhaps even more
importantly, the
tension on the line is infinitely variable and in complete control of the
operator.
Referring now to FIGS. 4-5, in an alternative embodiment of the present
invention, wire puller 400 includes a frame 470 and a stand 480 that supports
frame 470.
Stand 480 includes a base 490, a bracket 475 fixed to base 490, and a square
tube 488 that
is pivotally connected within bracket 475 by a pin 476 that extends through
holes in
opposing sides of bracket 475 and through holes in opposing sides of tube 488.
The
pivotal connection formed by pin 476 allows the entire wire puller 400
(excluding base
490) to pivot relative to base 490.
Frame 470 includes a drill restraint portion 440 that extends from square tube
488
to form a bracket 442. Bracket 442 receives handle 322 of power drill 320 so
as to
register power drill 320 with frame 470. Bracket 442 may be sized differently
and may
be positioned differently with respect to square tubing 488 to accommodate
different
models and types of power tools.
In the embodiment shown, a frame switch that includes a switch lever 445,
which
includes an eccentric switch actuator 447 is attached to drill restraint
portion 440. Switch
lever 445 pivots between an "on" position wherein it engages a power switch or
trigger
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switch 324 of power dri11320 (as shown in FIG. 4) and an "off' position where
it does
not engage trigger switch 324. In the embodiment shown, in the "on" position
switch
actuator 447 pivots into engagement with trigger switch 324 when switch lever
445 is
pivoted and continuously remains in that position until a user pivots it back
into the "off'
position. However, the frame switch could be some type of switch that does not
include
switch lever 445, such as a sliding switch, so long as it is easily moved from
the "on"
position to the "off' position and it remains in the "on" position without
constant force
from a user.
Square tube 488 is preferably secured to a housing 420 to form a drive shaft
mounting frame portion 510 of frame 470. Tube 488 may be secured to housing
420 by
welding or by any of many other well known methods, such as by bolts or
screws. In this
embodiment, housing 420 houses a transmission 422. Transmission 422 includes a
drive
shaft or input shaft 430 and an output shaft 434. Input shaft 430 includes an
end 432 that
is sized to mate with jaws 328 of chuck 326 of power dril1320. If some other
type of
power tool, such as an air wrench were used with wire puller 400, end 432
would be sized
and shaped in a manner so that it could be coupled with the rotary output of
that power
tool.
Transmission 422 preferably is such that the rotational speed of output shaft
434
is less than the rotational speed of input shaft 430. Also, transmission 422
is preferably
as light, durable, strong, and compact as possible. In the embodiment shown,
transmission 422 also includes a worm gear 424 that is fixed to an end 433 of
input shaft
430 opposite from end 432. Worm gear 424 preferably engages a helical gear
426.
Helical gear 426 is fixed to an end 436 of output shaft 434. A spoo1410 is
mounted on
an end 437 of output shaft 434 opposite from end 436. Thus transmission 422
transmits
torque from input shaft 430 to output shaft 434, and reduces the rotational
speed so that
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the torque of output shaft 434 is greater than the torque of input shaft 430.
Preferably, in
this embodiment the ratio of the rotational speed of input shaft 430 to the
rotational speed
of output shaft 434 is 10:1. Those skilled in the art will appreciate that
well-known gears,
bearing systems, and gear attachment systems may be used in transmission 422
as
described herein.
Depending on the desired output torque and the input torque of power dri11320,
the desired ratio may be different. A greater ratio would be desirable if the
input torque
of power drill 320 were less or if the necessary torque for pulling wire were
greater. In
fact, it may even be desirable in some situations to have the rotational speed
of output
shaft 434 exceed the rotational speed of input shaft 430. The worm gear-spur
gear
configuration used in this embodiment is light, compact, durable and strong.
However,
other types and configurations of transmissions could be used. For example, a
planetary
gear system might be desirable to produce ratios that are far in excess of the
10:1 ratio in
the embodiment described herein. Alternatively, a system of chains or belts
may be used.
Forearm frame portion 450 extends from, and is fixed to housing 420. More
particularly, a square tube (not shown) is fixed to housing 420 and extends
opposite from
square tube 488. A square tube 454 has a first end 455 and an opposing second
end 456.
First end 455 slides over the square tube that is fixed to housing 420. A pin
457 extends
through aligning holes in opposing sides of the square tubes to fix square
tube 454 to the
square tube that is fixed to housing 420. Second end 456 receives a square
tube 458, and
a pin 459 extends through aligning holes in second end 456 and square tube 458
to fix
square tube 454 to square tube 458. Preferably square tube 458 has multiple
holes along
its length so that it can be slid to any of multiple positions, thereby
adjusting the length of
forearm portion 450.
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A spoo1460 is attached to an end of square tube 458 opposite from its
attachment
with square tube 454. Thus, by adjusting the length of forearm portion 450 as
described
above, the position of spoo1460 relative to base 490 and the distance between
spool 460
and spool 410 is adjusted. Such adjustment is advantageous to allow wire
puller 400 to
be used in various different environments where lines need to be pulled.
Wire puller 400 preferably includes a support to prevent wire puller 410 from
rotating about pin 476 and to fix spoo1460 at a height. Referring to FIG. 6,
the support
can be a stand 520 that includes a pair of legs 522, 524. Each leg 522, 524 is
attached to
forearm portion 450. Preferably, legs 522, 524 are attached to opposing sides
of spool
460 by a pin 462 that also supports spoo1460 within forearm portion 450. Pin
462
extends through a hole in leg 522, through opposing holes in forearm portion
450,
through spool 460, and through a hole in leg 524. An additional bolt or pin
526 extends
through a hole in leg 522 and an aligned hole in forearm portion 450 to
prevent leg 522
from freely pivoting about pin 462. Likewise, a bolt or pin 528 extends
through a hole in
leg 524 and an aligned hole in forearm portion 450 to prevent leg 524 from
freely
pivoting about pin 462.
Each leg 522, 524 includes a square tube 530, 532 that extends away from
forearm portion 450, and a slightly larger square tube 534, 536 that extends
from square
tube 530, 532, respectively. Square tube 534 slides over square tube 530 and a
pin 538
extends through opposing holes in square tube 530 and square tube 534 to
secure tubes
530 and 534 together. Square tube 536 slides over square tube 532 and a pin
540 extends
through opposing holes in square tube 532 and square tube 536 to secure tubes
532 and
536 together. Tubes 534, 536 and/or tubes 530, 532 may each include multiple
holes so
that the tubes can be adjusted relative to each other to adjust the overall
length of legs
522, 524.
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Legs 522, 524 preferably each include a hinge 550 (hinge for leg 524 not
shown)
that allows the leg to pivot so that it will slope downwardly and outwardly.
However, the
outward slope of legs 522, 524 is constrained by a chain 560 that extends
between legs
522, 524. Although stand 520 has been described herein with particularity,
those skilled
in the art will understand that any of several other configurations for the
stand are
possible. For example, the legs 522, 524 could be fixed at a definite outward
slope rather
than being pivotally attached by hinges 550.
Referring to FIG. 7, alternatively, the support may be a mounting bracket 600.
Mounting bracket 600 includes arms 610, 612 that attach to forearm portion
450, and
form an extension of forearm portion 450. Preferably, arms 610, 612 define
holes that
receive pin 462 on opposing sides of spool 460. A pin 620 extends through
holes in
opposing sides of forearm portion 450 and through holes in arms 610, 612 to
prevent
bracket 600 from freely pivoting about pin 462. Preferably, arms 610, 612 also
support a
spool 630 therebetween. When in use with mounting bracket 600, a line is
preferably
guided by spool 630, rather than spool 460.
An adapter 640 is adapted to be secured to an opening of a conduit from which
wire is being pulled, and is preferably attached to bracket 600. Adapter 640
includes a
threaded tube 642 that engages a threaded end of a conduit. Adapter 640 also
includes a
tongue 644 fixed to tube 642 that slides into a slot 650 in bracket 600. A
bolt then
engages bracket 600 and tongue 644 to secure tongue 644 within slot 650 and
thereby to
fix adapter 640 to bracket 600. Bracket 600 keeps wire puller 400 from moving
relative
to an opening in a conduit from which wire is being pulled, whether the
conduit is above
ground or below ground.
CA 02325790 2000-11-14
Referring now to FIGs. 4-7, assembly of wire puller 400 includes the steps of
attaching forearm portion 450 to housing 420, attaching either stand 520 or
mounting
bracket 600 to forearm portion 450, positioning power drill 320 such that end
432 of the
wire puller drive shaft fits into jaws 328 of drill 320, and such that trigger
switch 324 of
power drill 320 can be depressed by rotating frame switch lever 445, and
tightening
power drill chuck 326 over drive shaft 430. Thus, the only attachment of the
power drill
to wire puller 400 is the drill jaw to drive shaft coupling. As described
above, this sole
point of attachment allows the power drill to be easily detached from the wire
puller,
when needed for other drill uses.
The wire puller is assembled and optimally positioned in close proximity to a
junction box or other location, from which the line is to be pulled. Unlike
the
embodiment shown above, forearm portion 450 of wire puller 400 is supported by
a stand
520 or a mounting bracket 600. Spool 460 or spool 630 in forearm frame portion
450 is
preferably aligned with an opening of a conduit from which the line is being
pulled to
minimize friction in pulling the line out of the conduit by adjusting the
position of base
490, pivoting wire puller 400 relative to base 490, and adjusting the length
of forearm
portion 450. Drive shaft end 432 is sized to be received within power drill
jaws 328.
Power drill 320 is positioned in drill restraint frame portion 440 to receive
drive shaft end
432 and to allow drill switch lever 445 and drill switch actuator 447 to
actuate power drill
320. Power drill chuck 326 couples power drill 320 to drive shaft end 432.
In operation, wire puller 400 operates in the same manner as wire puller 100
described above. More specifically, referring to FIG. 4, drill switch lever
445 and drill
switch actuator 447 are in the "on" position, thus depressing power drill
trigger switch
324 and actuating power dri11320. Actuating power drill 320 rotates drive
shaft 430 and
spool 410. The wire puller operator wraps line 310 around spool 410 for at
least one
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1 ~I
revolution. The wire puller operator then holds line 310 taut to establish
frictional
coupling between spool 460 and line 310. As the wire puller pulls line 320 out
of the
junction box, the wire puller operator accepts the feed to maintain the
frictional coupling
of line 320 and spool 410. The wire puller operates to pull line while the
power drill is
actuated and the line is frictionally coupled to spoo1410. To cease pulling
line 310, the
operator need only release the grip on line 310 to stop the frictional
coupling between
spoo1410 and line 310. Thus, line pulling can start and stop without the need
to rotate
drill switch lever 445, after initial actuation of power dril1320.
Wire puller 400 is more advantageous than wire puller 100 if a larger force is
required to pull the line. This is particularly true in light of transmission
422 for reducing
the rotational speed and thereby increasing the torque of wire puller 400.
Also, the
support that is included in wire puller 400 increases the wire puller's
ability to withstand
larger forces. Wire puller 400 is not as compact as wire puller 100, but it is
still extremely
compact and light, especially when it is disassembled.
Wire puller 400 or wire puller 100 may include an additional spool adjacent to
spoo1460 or 160. In this configuration, line 310 will extend over spool 460 or
160 and
under the additional adjacent spool so that the line forms an "S"-shaped
pattern. This
configuration is advantageous to keep line 310 aligned on the spools while it
is being
pulled from various directions, such as different heights or from the side of
the spools.
The additional adjacent spool is preferably mounted on the forearm portion
adjacent to
spoo1460 or 160 on the side opposite from spool 420 or 120, respectively.
While the invention has been particularly shown and described with reference
to
preferred embodiments thereof, it will be understood by those skilled in the
art that
various changes in form and details may be made therein without departing from
the
17
CA 02325790 2000-11-14
spirit and scope of the invention. Accordingly, unless otherwise specified,
any
dimensions of the apparatus indicated in the drawings or herein are given as
an example
of possible dimensions and not as a limitation.
18
