Note: Descriptions are shown in the official language in which they were submitted.
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Descr~ption
ROTAR~ CUTTER TOOL
Technical Field
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This invention relates to a rotary cutting tool
5 particularly adapted to easily cut "BX"- or "FLEX"-type
spirally-wound electrical cable armor or other elongated
articles.
Background Art
According to many local building codes, electrical
10 wiring which is not enclosed within a building's walls must
be protected in an armored sheath. This is normally done
by running the wire through either a relatively rigid,
although shapable, metallic conduit or by encasing the wire
in a flexible armor sheath. This flexible armor sheath is
15 commonly referred to as "BX", which is supplied with the
necessary wire conductors already encased therein, or
"FLEX", which is a flexible armor sheath into which the
necessary wires are introduced on site. Most commonly,
these flexible armor sheaths are constructed of a
20 helically-wound metallic, or reinforced nonmetallic,
material. Because of its helical construction, such an
armor sheath is difficuIt to cut with ordinary tools.
Various tools, such~ a~ those shown in U.S. Pat. Nos.
2,176,646 and 3,453,917, have been designed to p~ovide a
25 longitudinal cut along such helically-wound cable armor.
C. A. Thatcher (U.S. Pat. No. 25176~646) discloses a tool
for clamping cable armor in place and providing; a
longitudinal cut in the sheath. This device is relatively
large and is cumbersome for a worker to carry while on a
30 jobsite. It is a~so too large to conveniently be used in
clo~e quarters. ~ ~
F. J. Perry (U.S.~ Pat. ~No. 3,453,917) shows a rotary
cutter for flexible cable armor which clamps the sheath
into place and creates a longitudinal cut.
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Each of the above-described devices is limitea to a
specific use and does not allow the user to select the
angle at which the sheath is cut. Despite the disclosure
of these prior art devices, the heretofor most common
5method of cutting such cable armor is with an ordinary hack
saw. The cable sheath is held in one hand while the other
hand directs the saw diagonally across a helical strand of
the sheath until it is completely cut through one turn of
the helix. The sheath is then bent away from the cut line
lOto separate the helical turns. Although a hack saw has a
wide variety of alternative uses, it is still relatively
large to be carried on a worker's tool belt and can be
difficult to use in close quarters. Also, this method o~
cutting is slow and fatiguing to the worker. The hack saw
15blade is prone to slipping from its position on the sheath,
resulting in a jagged cut edge or injury to the worXer's
fingers.
Disclosure of the Invention
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The present invention provides a cutting tool with a
20rotary cutting element operably supported on a frame. The
cutting element rotates about an axis to present a
peripheral cutting edge. A pair of spaced-apart workpiece-
contacting elements are supported by the frame and
positioned on opposite sides of the cutting element,
25substantially axially spaced therefrom. The workpiece-
contacting elements make contact with spaced-apart portions
of an elongated workpiece radially outwardly of the cutting
edge~ The workpiece-contacting elements are yieldable
toward the cutting edge to an extent sufficient to allow
30relative movement of the cutting edge into cutting contact
with the workpiece while the workpiece-contacting elements
remain in contact with the workpiece.
The workpiece contacting elements may be in the form of
a pair of spaced-apart forks. Each fork includes a base and5a pair of tines extending from the base. Each tine has an
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outer end portion such that a space is defined be-tween each
pair of tines. The tines projec-t from the bases a distance
sufficient to position end portions of the tines outward o~
the rotary cutting element's rotary cutting edge. A pair
5Of yieldable guide members, each of which spans between the
tines of a fork, are placed against spaced-apart portions
of an elongated workpiece and are yieldable to an extent
sufficient to permit relative movement of the cutting
element into cutting contact with the workpiece. The
yieldable guide members remain in contact with the
workpiece as it is cut and brace the workpiece against
movement which is substantially tangential to the cutting
element.
The a~is of the rotary cutting element may be
5adjustable relative to the workpiece-contacting elements or
guide members to provide the workpiece with a substantially
transverse or slightly oblique cut. The
outwardly-extending tines or workpiece-contacting elements
normally protect the rotary cutting element ~rom
20inadvertent contact with other objects or surfaces.
It is an object of this invention to provide a
hand-held, multipurpose cutting tool which can be
conveniently carried by a worker and safely used,~even in
close quarters.
It is also an object of this invention to provide a
rotary cutting tool for c~tting eIongated objects, such ~as
armored cable sheath, without the necessity of engaging the
article in a clamping mechanism. The present invention
provides a guide; m~eans which facilitates ~he positioning of
30elongated articles to be moved into cutting contact with
the rotary cutting element.
Brief Description of the Drawinq:
Like reference numeràls are used to designate likesParts throughout the various ~igures o~ the drawing, and:
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Fig. 1 is a pictorial view of the cu-tting tool
according to the preferred embodiment of the invention;
Fig. 2 is a fragmentary enlarged view of a cutter head
portion fo the tool, shown engaging a portion of electrical
5 cable armor;
Fig. 3 is an end view of the cutting tooL showing the
blade in a first angled position;
Fig. 4 is a fragmentary side view of the tool showing
the cutter wheel in the first angled position;
Fig. 5 is a side view similar to Fig. 4, showing the
cutter wheel in a straight position and with -the guide
forks removed;
Fig. 6 is a view taken substantially along lines 6-6 of
Fig. 4, showing the attachment of a presser spring on a
15 fork and a cross-section of a ball bushing with a portion
of the cutter axle extending therethrough;
Fig. 7 is a sectional view taken substantially along
line 7--7 of Fig. 4, showing the attachment of a guide fork
to a support member;
Fig. 8 is a side view of the tool's cutter head with an
angled cutter wheel shown engaging a section of cable
armor;
Fig. 9 is a sectional view taken substantially along
line 9--9 of Fig. 8, showing a portion of cable armor cut
25 accordin~ to the engagement shown in Fig. 8;
Fig. 10 is a fragmentary, angled side view showing the
drive engagement of bevel gears;
Fig. 11 is a front view similar to Fig. 3, in which the
cutter wheel is shown in a straight position; and
Fig. 12 is an end view similar to Figs. 3 and 11,
wherein the cutter wheel is shown in a second angled
position.
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Best Mode for Carr~ing out the Invention
Referring to the various figures of the drawing, and
first to Fig. 1, therein is shown at 10 a cutting tool
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according to the preferred embodiment o~ the invention.
The cutting tool 10 includes a rotary cutting element in
the form of a circular blade 12 rotatably mounted on an
axle 14. The axle 14 extends between opposite side
5 portions 16, 18 of a support frame or yoke.
The side portions 16, 1~ of the frame e~ten~ forwardly
in a substantially parallel direction from the tool body
20. The tool body 20 includes a motor housing 22 and a
battery housing 24 which also serves as a grip handle. An
10 electric motor 19 which is powered by a rechargeable
battery pack 21 and is operated by a trigger switch 23 is
the preferred means for rotatably driving the blade 12. A
preferred drive connection will be further described in
detail later.
Referring now also to Figs. 2, 4, 8 and ~0, each side
portion 16, 18 is provided with a -fork 25, 27 which
includes a pair of outwardly-extending tines 26, 28, 30,
32. Each pair of tines extends from a base portion 34, 36
which is part of, or attached to, the side portions 16, 18.
20 The side portions 16, 18 and forks 25, 27 are spaced apart
substantially axially from the cutting blade 12. Extendin~
between each pair of tines 26, 28, 30, 32 are resiliently
yieldable guide members. In preferred form, these yield-
able guide members are coil springs 38, 40 having ends
25 attached to outward end portions of the tines 26, 28,
30, 3~.
As shown in Figs. 4 and 8, the forks 25, 27 project
outwardly beycnd the cutting edge of the blade 12. In this
manner, the blade 12 i8 normally substantially protected
30 from inadvertent contact with other objects or surfaces.
The forks 25, 27 are set wide enough to shield the blade
not only forwardly but also on top and bottom sides. Rear
blade shields 42, 44, which are preferably constructed from
transparent materiaI, may~be provided to further protect
35 the hands ~nd eyes of the worker u~ng the tool 10.
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In use, ~n elongated workpiece 46 is positioned to
extend substantially parallel to the axle 14 between
respective pairs o~ tines 26, 28, 30, 32 and against the
resiliently yieldable guide ~embers (springs 38, 40). The
S tool 10 is then moved toward the workpiece 46, deflecting
the guide springs 38, 40 until the blade 12 comes into
cutting contact with the workpiece 46. The springs 28, 40
resiliently bend and stretch to substantially conform with
the shape of the workpiece 46 and to provide a "bed" or
10 bight against which the workpiece 46 rests so that the
workpiece 46 will resist tangential movement relative to
and caused by the rotating cutting blade 12. A "cradling"
e~fect created by the resilient guide members 38, 40 also
facilitates proper alignmen~ of the workpiece 46 relative
15 to the cutting blade 12.
According to one aspect of the invention, the angle at
which the cutting element 12 contacts the workpiece 46 may
be adjusted to be either perpendicular or angled to provide
either a transverse or an oblique cut in the workpiece 46.
20 Normally, when the workpiece 46 is "BX" or "FLEX"
helically-wound flexible cable armor, the cutting blade 12
is positioned to contact the workpiece 46 slightly angled
from perpendicular. The tool 10 is illustrated with the
cutting blade 12 in this position in Figs. 1-4, 8 and 10.
25 This angle, shown as "A" in Figs. 3 and 9, provides a cut
47 substantially across a single turn of the
helically-wound sheath 46. Angle A represents the degree
to which the axis of the cutting blade 12 is rotated from
perpendicùlar relative to the direction of the side
30 portions 16,:18, forks 25, 27, and guide springs 38, 40.
This angle A is typically approximately 25. If the tool
10 is to be used only for cutting the above-described type
of workpiece 46, the axle 14 may be permanently secured in
this position relative to the guide means. However, to
35 maXe the tool 10 usable ~or a plurality o~ cutting
purposes, the axle 14 may be constructed to be adjustably
positioned between the side portions 16, 18.
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The preferred means for adjusting the angle of the
cutting blade 12 is to support opposite end portions 46, 48
of the axle 14 in floating bearings 50, 52 which are
slidably positionable along slots 54, 56 formed in the
soppOsite side portions 16, 18.
Referring now to Fig. 6, each floating bearing 50, 52
is in the form of a ball bushing 58 having a central bore
60 -through which an end portion 46 o~ the axle 14 extends.
The ball bushing 58 is captured in a socket 62. The socket
1062 is notched (at 64) to be slidably held within the slot
54, 56. The floating bearing 50, 52 may be infinitely
positionable along the length of the slot 54, 56 or may
also be releasably held at definite positions, such as at
extreme opposite ends, along the slot 54, 56 by detents
15(not shown), or the like.
The illustrated embodiment includes slots 54, 56 which
extend from a central, aligned position to oppositely-
directed positions. This allows the axle 14 and blade 12
to be positioned as shown in Figs. 3 and 11, and infinitely
20therebetween. If desired, the slots 54, 56 may extend in
both directions from a central location to allow the axle
14 and blade 12 to be angled in the opposite direction, as
shown in Fig. 12. Such an angle would not be desirable for
cutting BX or FLEX, but could be desirable for other
25cutting purposes.
In preferred form, the circular cutting blade 12 is
driven by a battery-powered electric motor 19 having a
drive shaft 66 which extends substantially perpendicular to
the axle 14 and axis of the cutting blade 12. The drive
30energy is transferred to the cutting wheel 12 through a
pair of complementary~bevel gears 68, 70. The driven gear
70 is mounted along with the cutting blade 12 on a hub or
bearing 72. In this mbodiment, the axle 14 is fixed in
place and the~bearing 72, along with driven gear 70 and
35cutting blade 12, rotate thereon. The bevel gears are held
into lntermeshing contact by coil springs 74, 76. In this
manner, drive gear 68 is relatively fixed in place while
driven gear 70 is longitu~inally positionable along the
axle 14. This allows the driven gear 70 to align itself
against the drive gear 68 as the axle 14 is adjusted in
5 position from ~hat shown in Fig. 11 to that shown in either
of Figs. 3 or 12. Gearing ratios may be selec~ed as
necessary to provide proper power and speed. It is
preferred that ~he electric motor 19 is selected to rotate
at approximately 2,700 - 3,000 rpm. The cutting blade 12
lOis selected to operate at variable high speeds.
According to another aspect of the invention, the forks
25, 27 may be removable to allow varied uses of the cutting
tool 10. In preferred form, each fork 25, 27, including
its respective tines 26, 28, 30, 32 and presser spring 38,
15 40, is attached to the side portion 16, 18 of the support
frame by screws 78, 80. The base portions 34, 36 of the
Eorks 25, 27 are provided with a groove 82 which mates with
a corresponding groove on the outward edge of the side
portions 16, 18 of the frameO This provides a detachable,
20but rigid, connection between the members. The forks 25,
27 may also be moved to expose the cutting blade 12 in
other manners (not shown) such as providing a hinge
connection between the forks 25, 27 and respective side
portions 16, 18 of the frame, or by pivotally connecting
25the tines 26, 28, 30, 32 to their respective base portions
34, 36. Without the protective extensions of the tines 26,
28, 30, 32, the cutting blade 12 may be exposed for use in
close quarters or for cutting sheet materials. The cutting
blade 12 may be interchangeable as needed to cut wood,
30metal, plastic, or other materials~
It is to be understood that the aspects and features of
this invention may be practiced in many forms other than
the preferred, illustrated embodiment. Therefore, my
patent protection is to be measured and limited only by the
35appended claim or claims, interpreted according to accepted
doctrines of claim interpretation, including the doctrine
oE equivalents.
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