Note: Descriptions are shown in the official language in which they were submitted.
CA 02243833 1998-07-17
TOOL FOR REMOVING INSULATION FROM WIRES
Field of the Invention
The present invention relates to the filed of hand tools
for stripping insulation from electrical wires and cables.
Hackc~round of the Invention
There exists a need .for a tool that can be used to quickly
and effectively remove insulation, such as plastic
(polyethylene, PVC, etc.) from electrical wires and cables.
Many tools and techniques intended to be used to accomplish
this task exist, but there are drawbacks associated with each.
For instance, a common type of tool for stripping insulation
comprises a metal strip with a sharpened notch cut in it. The
insulated wire is placed in the notch, and the strip then drawn
to the end of the wire, to pull the insulation away. Such a
tool is limited in its application, though, since the size of
the notch will match only a limited number of wire sizes.
Wire stripping pliers are also known. These are provided
with heads that have aligned notches to close over a wire, and
cut the insulation, to permit it to be pulled away. Again,
however, the notches are sized to particular wire sizes, and
so such a tool has limited usage. That is, if the notches are
closed over a wire that is too large, the wire may be cut by
-1-
CA 02243833 2001-07-26
the notches. If they are closed over a wire that is too small,
the insulation will not be caught.
Moreover, in cable construction, it is common to find an
insulating or protective layer over two or three wires, and
other elements, including strength elements, braided
cushioning, and the like. To connect a cable, then, it is
often necessary to cut. away several layers, of insulation,
sheathing and fibrous elements, before the insulated wires
requiring connection are exposed. Therefore, it is common for
l0 electricians to carry all purpose knives, with sharp cutting
edges for cutting away layers.
In view of the faregoing, the object of the present
invention is to provide a simple and effective tool for
stripping insulation from wires of a variety of sizes, without
damaging the metal core of the wire. A further object of the
present invention is to provide an all purpose knife with a
piercing and cutting blade for stripping the outer, fill, and
strength elements from a cable, and an integral insulation
stripping blade for stripping the insulation from wires,
regardless of the gauges of the wire, or the thickness of the
insulation thereon.
CA 02243833 2001-07-26
In a broad aspect, then, the present invention relates to
a tool for stripping insulation from wire, said tool having a
handle and a knife blade extending therefrom, said knife blade
having a flat surface and a sharp edge, a secondary blade being
provided on said knife blade, the secondary blade being formed
as a lateral projection of a portion of said knife blade and
being offset from the knife blade, the secondary blade extending
substantially parallel to the sharp edge of said knife blade.
Brief Description of the :Drawings
In drawings that illustrate the present invention:
Figure 1 is a perspective view of a tool according to a
first embodiment of the present invention;
Figure 2 is a side view of the tool shown in Figure 1 from
the blade edge thereof;
Figure 3 is a front view thereof;
Figure 4 is a side view of a second embodiment of the
present invention;
Figure 5 is a side view of a third embodiment of the present
invention;
Figure 6 is a cross-sectional view, through line IV-IV in
Figure 3;
Figure 7 is a cross-sectional view, similar to Figure 6,
showing a second form of insulation stripping blade in connection
with the tool of the present invention; and
-3-
CA 02243833 2001-07-26
Figure 8 is a cross-section view, similar to Figure 6
showing a third form of insulation stripping blade in connection
with the tool of the present invention.
-3a-
CA 02243833 1998-07-17
Detailed Descriytion of the Drawincts
Referring to the drawings, Figures 1 - 3 and 6 illustrate
the most basic embodiment: of the present invention. The tool
1 of the present invention may, as illustrated in these
drawings, have an overall shape resembling a utility knife,
with a handle 2, and a blade 3. The blade has a cutting edge
4, and a piercing point 5. In a knife of this sort, the blade
edge 4 is, preferably, generally concavely curved in the region
of the point 5, to permit the point to be drawn over a
substrate to be cut, such as the sheathing for a cable.
The blade 3 is provided with a centrally located
insulation skinning element 6, which is formed integrally with
the blade, by the offsetting of a portion of the blade, and the
sharpening of the edge '7 thereof . The edge 7 , as shown in
Figure 4, is substantially parallel to the blade 3 of the tool,
so that the edge 7 of th.e insulation skinning element can be
drawn over a wire to remove insulation therefrom, in the manner
of a plane.
The skinning element 6 of the blade may be formed by
punching the element 6 into the blade, and then sharpening the
edge 7 thereof.
As illustrated in Figure 7, in a second form, a version
of the embodiment illustrated in Figures 1 - 3 and 6, suitable
-4-
CA 02243833 1998-07-17
for right or left-handed use is provided. In this embodiment,
elements 6 and 8 are offset from different sides of the blade,
an equal distance, to provide oppositely directed sharp
skinning edges 7 and 9. Edge 7 is suitable for use with the
handle in one hand, and edge 9 suitable for use with the other
hand.
In this regard, it will be noted that depending on the
user, and their preference, element 7 or element 9 may be
considered right-handed, and vise-versa. That is, a right-
handed user may choose to grasp handle 2 with the right hand,
and skin a wire from beneath same, exerting pressure with the
right thumb on the wire to bring it to bear against the edge
7 of element 6. Alternat=ively, the user may grasp the handle
2 in the right hand, and press downwardly on an insulated wire
resting on a work surface, and skin the insulation off of it
by moving the edge 7 against the insulation. In either event,
it will be observed that for a left-handed user, the oppositely
directed edge 9 will be utilized.
In a third form as shown in Figure 8, the tool has a blade
3 that has two elements ~, 10, with cutting edges 7, 11 offset
different depths. This feature is useful in circumstances
wherein two thicknesses of insulation are frequently
encountered. This circumstance occurs, for instance, in
residential construction.
-5-
CA 02243833 1998-07-17
Figures 4 and 5 illustrate useful combination tools
embodying the present invention.
In Figure 4, the tip of blade 3 is formed as a slotted
screwdriver head 13. Near the base of the blade, a small
circular aperture 12 is :formed in the blade. Aperture 12 is
useful in assisting an electrician to bend the end of a wire
into a loop for connection to an electrical switch, outlet,
panel, or the like.
In the embodiment illustrated in Figure 5, blade edge 4
is cured, as is preferred by some persons. Slotted screwdriver
head 13 is also formed at the tip of the blade, and aperture
12 is provided at the base of the blade. Moreover, a notch 14
is formed on the back edge of the blade, for quick removal of
small amounts of insulation from wires.
Utilizing the tool of Figures 4 or 5, then, an electrician
can prepare and install a cable to a switch panel, outlet or
the like without changing tools.
It is to be understood that the examples described above
are not meant to limit the scope of the present invention. It
is expected that numerous variants will be obvious to the
person skilled in the field to which the present invention
pertains without any departure from the spirit of the
-6-
CA 02243833 1998-07-17
invention. The appended claims, properly construed, form the
only limitation upon the scope of the invention.
