Precision small wire and untwisting tool

A multi-purpose hand tool for use with fine gauge insulated wire. The hand tool can be used to cut wire, to cut and strip insulation from wire and to untwist twisted pairs of wire. The insulation cutting and stripping portion of the tool has an alignment guide for the wire which floats relative to the cutting blade for accuracy of alignment of the wire with the insulation stripping aperture. The wire untwisting means includes plastic pads carried by the tool members and movable into closely spaced relationship with each other upon closing of the tool to engage and straighten the wires of a twisted pair of wires pulled between the pads.

SUMMARY OF THE INVENTION 
This invention is concerned with a precision hand tool useful for cutting 
and stripping the insulation of an insulated wire, for untwisting a pair 
of twisted wires and for cutting insulated wires. It is particularly 
concerned with such a multi-purpose tool for use with fine gauge insulated 
wire. 
An object of this invention is a hand tool having means for cutting and 
stripping the insulation of an insulated wire of fine gauge without 
nicking the wire. 
Another object of this invention is a hand tool having insulation stripping 
means for fine gauge wire in which the wire is aligned with the insulation 
cutting blade by a floating wire guide. 
Another object is a tool having means for untwisting a twisted pair of fine 
gauge wires. 
Another object is a hand tool having wire untwisting means consisting of a 
pair of plastic pads that engage and straighten the wires of a twisted 
pair of wires pulled between the pads. 
Another object is a precision hand tool capable of simultaneously stripping 
a pair of fine gauge insulated wires. 
Other objects may be found in the following specification, claims and 
drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 of the drawings shows a hand held tool 11 which may be used for 
cutting and stripping insulation from wire of fine gauge. The tool is 
especially useful in stripping insulation of synthetic plastic which is 
extremely tough and difficult to cut. The tool includes two elongated 
members 13 of almost identical construction. Conveniently, these members 
may be metal stampings. Each elongated member includes a handle portion 15 
and a wire cutting blade portion 17. The blade portion of each member is 
offset both from the axis of the handle portion and laterally from the 
plane of the handle portion. The offset of the blade portion from the 
plane of the handle portion is equal to one half the thickness of the 
handle portion so that the blade portions are flush with each other when 
the handle portions are aligned as shown in FIG. 2. The elongated members 
13 are pivotally connected by a rivet 19 extending through openings (not 
shown) formed in the offset portions of the members. Each wire cutting 
blade portion includes an arcuate slot 21 and a projecting pin 23 each 
located on opposite sides of the rivet opening. The pin 23 may be force 
fitted into a suitable hole (not shown) formed in the member. The 
projecting pin of one member fits into the slot of the other member with 
the pin and slot forming stop means to limit opening pivotal movement of 
the elongated members 13 relative to each other. 
A projection 27 is formed on an edge of each handle portion. These 
projections are similarly located on each handle portion so that they move 
into contact with one another when the handles are pivotally moved 
together. A semi-cylindrical groove 29 is formed at the contacting edges 
of each projection. The groove 29 extends partially through the thickness 
of the handle portion 15. The groove terminates in a semi-cylindrical 
cutting edge 31. The groove and cutting edge may be formed by drilling 
through the handle portion so that only the tip of the drill extends out 
of the handle portion. In order for the cutting edges 31 on the pair of 
handle portions to be located on the same side of the tool, it is 
necessary for the grooves to be drilled from opposite sides of each of the 
handle portions. 
When the projections 27 come together upon actuation of the tool, the 
semi-cylindrical grooves 29 and cutting edges 31 form an insulation 
supporting tube and insulating cutting element having an aperture. The 
cutting aperture has a diameter no less than the diameter of the core 
portion of the wire to be stripped and the insulation supporting tube has 
a diameter no less than the outside diameter of the insulation jacket of 
the wire. 
A wire alignment guide 41 formed of a suitable plastic such as nylon is 
mounted on the insulation cutter edge side of the tool. The wire alignment 
guide includes an elongated rectangular base 43 which extends between the 
handle portions 15. Stubs 45 formed on the base extend through arcuate 
slots 47 formed in the handle portions 15. Spring like locking grippers 49 
fit over the stubs and hold the wire alignment guide in position on the 
tool. The opposite side of the base 43 from the stubs has an upstanding 
cylindrical projection 51 formed thereon. An opening 53 extends axially 
through this projection and the base. The opening has a funnel shaped 
entrance 55 which merges with a cylindrical passage 57. The cylindrical 
passage has a diameter substantially equal to the outside diameter of the 
insulation of the wire to be stripped. 
The arcuate slots 47 in which the wire alignment guide rides are located on 
the same circle as the semi-cylindrical grooves 29 and cutting edges 31. 
The slots are formed so that the ends of the slots will contact the stubs 
45 of the wire alignment guide to center the cylindrical passage 57 of the 
guide with the cutting aperture as the projections 27 contact each other. 
A pair of wire untwisting pads 61 are mounted on projections formed on the 
handle portions 15 adjacent to the projections 27. The pads 61 are formed 
of a suitable relatively soft plastic such as nylon and are of identical 
construction. Each has an outwardly extending portion 63 at one end 
thereof which overlaps the other pad 61 when the handle portions are moved 
together upon closing movement of the tool. The faces 65 of the pads are 
moved close to but not in contact with each other upon closing of the 
tool. The pads may be closed on a pair of twisted wires to thereby form a 
restricted passage for the wires. 
A compression spring 69 fits over projections 71 formed on the handle 
portions 15 to bias the handle portions away from each other. Insulating 
sheaths 73 fit over the handle portions outwardly of the compression 
spring 69. The insulating material may be vinyl or other suitable 
material. 
A modified form of wire alignment guide and insulation cutting and 
stripping projections is shown in FIGS. 5 and 6 of the drawings. The 
modified guide and cutting projections are provided to simultaneously 
strip two wires. The modified alignment guide 81 is formed of a suitable 
plastic and includes a base 83, stubs 85 to opposite ends of the base 
which extend through the arcuate slots 47 formed in the handle portions 15 
of the tool 11. Locking members 49 fit over the stubs to hold the wire 
alignment guide 81 in position of the cutting tool. The wire alignment 
guide has a generally cylindrical upstanding projection 87 formed on the 
base 83 on the side opposite to the stubs 85. A pair of openings 89 extend 
axially through the projection and the base 83. Each opening has a funnel 
shaped entrance 91 which connects with a cylindrical passage 93. The 
diameter of the cylindrical passage 93 is approximately equal to the 
outside diameter of the insulation of the wire to be stripped. 
The projections 101 formed on the handle portions 15 each have a pair of 
spaced semi-cylindrical grooves 103 with each groove having a 
semi-cylindrical cutting edge at one end thereof. When the projections 101 
are brought together, the grooves 103 formed insulation supporting tubes 
and insulation cutting apertures. Whereas in this example, the 
semi-cylindrical grooves and cutting edges are of the same diameter, as 
would be necessary for cutting both strands of the twisted pair of wires, 
it should be understood that these grooves and cutting edges could be of 
different diameters for use with wires of different diameters. 
The use, operation and function of this invention are as follows: 
The multi-purpose hand tool 11 of this invention is intended for use with 
fine gauge insulated wire of the type commonly used in electronic devices. 
Wire of this type ranges in size from 18 to 32 A.W.G. and smaller. The 
wire core in usually covered with a synthetic plastic insulation. This 
insulation is very thin and very tough and is exceedingly difficult to 
remove without nicking the wire core. These wires frequently are found in 
twisted pairs, especially in electronic communication devices. 
The blades 17 of this multi-purpose tool are used to cut wire. These 
blades, which are shown as having a 90.degree. cutting angle as would be 
obtained from a stamping, may also be provided with a tapered cutting 
edge. In addition to use in cutting, the tool of this invention may also 
be used for stripping insulation from the ends of wires. The end of the 
wire to be stripped is inserted into the funnel shaped entrance 55 of the 
wire alignment guide 41. The wire is pushed through the guide so that it 
extends between the insulation cutting blades or projections 27 formed on 
the handle portions 15 of the elongated members 13. The moving together of 
the handle portions 15 of the tool will force the wire alignment guide 41 
into alignment with the semi-cylindrical cutting edges 31 of the 
insulation cutting blades. The semi-cylindrical grooves 29 formed in the 
projections 27 are also centered upon and engage the insulation covering 
the wire thereby providing support for the insulated wire while the 
insulation is being cut by the cutting edges 31. The cutting edges 31 cut 
through the insulation but stop short of the core of the wire. With the 
handle portions 15 held together, the insulation is stripped from the wire 
by moving the tool relative to the wire. 
The modified form of tool shown in FIGS. 4, 5 and 6 of the drawings may be 
used to simultaneously strip insulation from both wires of a pair of 
wires. Additionally, the wire stripping cutting elements 103 may be of 
different sizes so that wires of different diameters may be stripped 
either simultaneously and individually. 
The tool of this invention may also be used for untwisting pairs of twisted 
wires. The wires are untwisted by inserting them between the wires 
untwisting pads 61 which are formed of a soft plastic such as nylon. When 
the wires are positioned between the pads, the handle portions 15 are 
moved together moving the pads towards each other and trapping the pair of 
twisted wire between the faces 65 of the pads and the overlapping portions 
63 of the pads. With the faces 65 of the pads held in close proximity of 
one another, the twisted wire is pulled between the pads. The pads engage 
the wires and tend to parallel the wires and untwist them. 
The compression spring 69 urges the handle portions 15 apart which carries 
the blades 17 to their open position. The amount of opening of the blades 
is controlled by the stop members 23 which ride in the slots 21 formed in 
the blade portions.