Hand tools abstract
A method for insulating hand tools includes the application of
a first and a second coating of protective insulating material along
the handle of the tool. Inserting the end of the handle into a heat
shrinkable end cap and providing heat to the cap to shrink it and
thus seal the end of the tool. The added protection this end cap
provides is both as an additional insulation as well as an increase
in the impact strength of the tool.
Hand tools claims
1. A method for protecting insulated hand tools, comprising:
providing an uninsulated hand tool, said hand tool having at least
one handle, said handle having an end;
applying a first protective coating over the majority of said handle
and said end;
applying a second protective coating over said first protective
inserting said end into a heat shrinkable end cap; and
providing heat to said end cap thereby shrinking said cap about
said end to form a seal.
2. The method of claim 1 wherein said first coat is a first color
and said second coat is a second color.
3. The method of claim 2 wherein said first color is white and
said second color is orange.
4. A method for protecting insulated hand tools as defined in claim
1 wherein said first and said second are comprised of a PVC based
5. A method for protecting insulated hand tools as defined in claim
1 wherein said end cap includes an inside surface, said inside surface
having an adhesive thereon.
Hand tools descriptionBACKGROUND OF THE INVENTION
The present invention relates generally to a method for providing
protection to insulated tools, and more particularly to the utilization
of end caps on the bottom handles of insulated tools to increase
the impact test performance of the tool.
In order to reduce the chance of injury, particularly electrical
shock, where a tool may make contact with an energized source, tools
have historically been insulated upon their handle portion. Such
insulation must meet current American Society for Testing and Materials
(ASTM) standards for both a voltage insulation rating as well as
an impact test performance. At the time of this writing, the current
voltage insulation rating is 1000 volts, and the current impact
test standards require a 2 meter equivalent ambient impact test
followed by a 0.6 meter equivalent cold temperature (-25.degree.
C.) impact test.
The use of a typical insulated tool, although inadvertently, most
certainly includes mishandling or slippage which leads to a dropping
thereof. Such dropping, when subjected to a substantial impact,
as onto a hard surface from a substantial height may cause the insulation
on the handle ends to become damaged. Additionally, a premature
wearing down with which such a tool may be subjected to may cause
user dissatisfaction. These situations in turn requires the tool
to be prematurely removed from service.
Accordingly, it is a general object of the present invention to
provide a new and improved method for providing protection to insulated
It is a more specific object of the present invention to provide
an end cap upon the bottom handles of insulated tools to increase
the impact test performance thereof.
Another object of the present invention is to provide a cost-effective
solution to the wear and tear problem of insulated tools.
These and other objects, features and advantages of the present
invention will be clearly understood through a consideration of
the following, detailed description.
SUMMARY OF THE INVENTION
The invention is directed to a method for protecting insulated
hand tools, which method comprises applying a first protective coating
along the handle portion of a tool; applying a second protective
coating over the first protective coating; inserting the end of
the handle of the tool into a heat shrinkable end cap; and providing
heat to shrink the cap around the end to provide a seal thereon.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention which are believed to be
novel are set forth with particularity in the appended claims. The
invention, together with the further objects and advantages thereof,
may best be understood by reference to the following description
taken in conjunction with the accompanying drawings, in the several
figures of which like reference numerals identify like elements,
and in which:
FIG. 1 is a frontal view of a typical forged steel handle pliers
FIG. 2 is a frontal view of the pliers of FIG. 1 with a first protective
coating on the handles thereof;
FIG. 3 is a frontal view of the pliers of FIG. 2 with a second
protective coating on the handles thereof;
FIG. 4 is a frontal view of the pliers of FIG. 3 constructed in
accordance with the principles of the present invention;
FIG. 5 is a cross-sectional view of one of the handles of FIG.
4 depicting each layer of protection;
FIG. 6 is an exploded view of one of the handles of FIG. 4 depicting
the relative dimensions of each layer of protection;
FIG. 7A illustrates a handle of FIG. 3 and an expanded end cap
of the present invention;
FIG. 7B illustrates the application of heat onto the end cap of
FIG. 7A when the handle is inserted thereto;
FIG. 8 illustrates the fully recovered (after heating) end cap
of FIG. 7B as it seals the handle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, and particularly to FIG. 1 a typical
forged steel handle pliers 10 includes a pair of opposed handle
portions, a left handle 12 and a right handle 14 pivotal about
a flush rivet 16. Actuation of these handle portions about the rivet
pivots the corresponding jaw portions, the left jaw 18 corresponding
to the right handle 14 and the right jaw 20 corresponding to the
left handle 12. Each jaw portion includes a gripping portion 22
and a cutting portion 24. Although the preferred embodiment illustrates
a long-nose pliers for use with the present invention, it will be
understood that this long-nose pliers is for illustration purposes
and the present invention is not deemed to be limited to the application
thereof. Other insulated tools for which the present invention is
applicable includes, but in no way is limited to, all varieties
of pliers, crimping tools, stripping tools, and cable cutters.
FIG. 2 illustrates the use of a first coating 26 over the handles
of the pliers 10. Typically, in the case of a regular set of pliers,
this first coating is designed to give the user a better grip for
a more precise or stronger hold. However, for insulation and purposes
of the present invention, the first coating 26 as shown in FIG.
2 is provided to protect the user as an insulating cover. The common
means in the tooling industry for applying this first coat, comprised
of a PVC based plastisol, is by dip molding. This plastisol dipping
method requires a dip molding for the initial application of the
first coating followed by the correct curing temperature for an
amount of time such that the plastisol bonds with the steel handle.
Whatever the method and however applied, this first coat results
in a covering (typically colored) cast on the metal handles of the
pliers. This insulating covering is designed to be irremovable.
The high-dielectric white inner coating is bonded to the tool and
makes sure of an immediate, definitive and total insulation of the
FIG. 3 is illustrative of the use of a second coating 28 applied
over the first 26. This second coat is again comprised of a PVC
based plastisol and is designed to be irremovable and flame retardant.
This coating is applied not only for its flame-retardant and impact-resistant
properties, but also, secondarily, as a wear-and-tear, indicating
source. In particular, as this second coat 28 is typically orange
and the first coat 26 is typically white, if the orange coating
28 cracks, breaks or becomes damaged enough so as to enable the
white inner layer to become visible, this is indicative of an unsafe
tool and one that must be immediately destroyed.
Application of this second coat 28 is much like the first. A plastisol
dipping method is used which requires a dip molding for the initial
application of the second coating followed by the correct curing
temperature for an amount of time such that the second coat of plastisol
bonds with the first.
What results is depicted in FIG. 3. This outer coating may include
ridges 30 on the outer surface of the handle portions to aid in
the gripping of the tool. Integral guards 32 are employed to help
prevent hand contact with the conductive parts of the tool.
The method of the present invention is utilized to protect these
coated ends and prolong the life of the insulated tools in general.
This is accomplished by providing end caps 36 over the ends 34 of
the outer covering, as shown in FIG. 4.
The steps used to accomplish the method of the present invention
are depicted as completed in order through FIGS. 1-4. FIGS. 5 and
6 illustrate those steps as a cross-sectional view and an exploded
view respectively depicting each layer of protection and the relative
dimensions thereof. As shown in FIGS. 5 and 6 the right handle
14 of the pliers 10 is first bonded with the high-dielectric white
inner coating 26. Over the inner coating 26 the outer flame retardant,
impact-resistant coating 28 is applied. Finally, the end caps 36
are applied to the ends 34 of the outer coating according to the
principles of the present invention.
The end caps 36 for use in the present invention are preferably
heat shrinkable with adhesive in order to provide the tightest weather-tight
seal over the ends 34 of the handles. The end caps used by the preferred
embodiment are commercially available through Raychem Corporation
and designated type 101A052. However, other heat shrinkable end
caps may be used, such as those provided by 3M Electrical Specialties
Division and the like. Although the preferred application method
of the present invention involves the heat shrinking of the caps
36 over the ends 34 it should be understood that the present invention
is not intended to be limited thereto. Other means of applying the
caps 36 may include the use of an adhesive material, a vacuum fit,
or any other similar means.
The heat shrinking of the cap is illustrated in FIG. 7. FIG. 7A
shows a handle of a pair of pliers including the outer coating 28
and ridges 30 along with an expanded (before heating) end cap 38.
FIG. 7B shows the end 34 of the handle inserted into the expanded
end cap 38 and the subsequent application of heat thereto by a heating
source 40. This heating source may be in the form of a blower (preferred),
a heating chamber or any similar means. After heating, as shown
in FIG. 8 the expanded end cap 38 (FIG. 7B) becomes fully recovered
36 and shrinks to seal around the end of the handle and creates
a smooth covering with no loose ends.
Thus, a method for providing protection to insulated tools has
been described. The method requires minimal effort on the part of
the manufacturer, making it a very cost-effective way to enhance
the operation of and prolong the life of insulated tools. Furthermore,
these caps not only provide for extra insulation, but increase the
impact test performance well past both the ambient and cold standards
of the ASTM.
While a particular embodiment of the invention has been shown and
described, it will be obvious to those skilled in the art that changes
and modifications may be made therein without departing from the
invention in its broader aspects, and, therefore, the intent in
the appended claims is to cover all such changes and modifications
as fall within the true spirit and scope of the invention.