Note: Descriptions are shown in the official language in which they were submitted.
CA 02334425 2001-02-06
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ERGONOMIC DRYWALL KNIFE
Field of the invention
The present invention relates to a drywall knife.
More particularly, the present invention relates to an ergonomic drywall
knife for use in drywall applications and the like, said drywall knife
comprising an
ergonomic rubberized handle which is lightweight, enables comfortable and
multiple hand gripping and has a long-lasting logo. Furthermore, the blade of
the
drywall knife is mounted to the handle without the use of fasteners.
Background of the invention
Drywall knives are very well known in the art. They generally consist of a
manipulative handle onto whiclh a blade is securely mounted. The drywall knife
can be used by workers to carry out various tasks on drywall and the like. The
blade is usually mounted onto the handle by means of fasteners such as bolts
and
nuts and/or rivets. This is a costly way of manufacturing and assembling
drywall
knives since using fasteners calls for added parts and added assembly steps.
Therefore, it would be useful to provide a drywall knife whose blade is
mounted
onto the handle without the use of fasteners.
It is also known in the art that workers employing drywall knives usually
work for long periods of time aind the nature of their work requires them to
have
their arms in a usually extended manner so as to be able to carry out their
tasks
on drywalls and the like. Furthermore, they often need to use their drywall
knives
in order to plaster and smooth out drywall with a usually thick and heavy
pastelike
mixture, this too being also ven/ tiring on the workers' arms. Therefore, it
would be
very useful to provide a drywall knife which is inherently lightweight due to
its
design.
It is also known in the art that these same workers need to use drywall
knives in order to cut, plaster, or finish drywalls and the like, and the
various tasks
needed to be carried out often require the drywall knives to be manually
gripped
by the workers in different manners. However, most of the drywall knives in
the art
are of unwieldy nature because: of their shape and size, having often rough
edges,
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which make handling of the drywall knives cumbersome and/or strenuous on
workers' hands. Therefore, it would be very useful to provide a drywall knife
with
an ergonomic handle enabling comfortable and multiple hand gripping.
It is further known in the art that manufactures often display information on
the products they sell by mearis of labels secured to these same products or
by
simply printing the information onto the products. However, very often, the
labels
are deteriorated or become cietached and the prints fade out after a while.
Furthermore, this additional step of having to label a product after it has
been
manufactured constitutes additional costs. Therefore, it would be very useful
to
provide a drywall knife having a handle which is manufactured by a molding
process which is capable of producing a sign on the handle of the drywall
knife
while the handle is molded, said sign lasting all throughout the working life
of the
drywall knife handle.
US patent No. 5,956,799 granted on September 28t", 1999 to Panaccione
et al. describes an ergonomic putty knife and scraper handle manufactured from
at
least two different hardness injection molded polymers having a plurality of
harder
longitudinal ribs embedded in a softer overlay but exposed on both top and
bottom
surfaces in strategic locations. The longitudinal ribs provided non-binding
contact
with fabric surfaces to ease thE> insertion and removal of the handle into and
from
a user's pocket for temporary storage of the tool when not in use. When
employing
the tool for its intended purpose, however, the user enjoys the comfort,
efficiency
and safety of an ergonomic handle offering a "soft touch" to thumb and fingers
in
those locations requiring superior grippability.
US patent No. 5,615,445 granted on Aprillst, 1997 to Kelsay et al.
describes a taping knife which includes a blade with an elongated handle
secured
to the blade. The plastic handle includes a durable inner member and a
grippable
outer core. The hollow inner member is formed from adjoining member halves
which have an inner structural support network of ribs. The handle component
parts sealably interlock and are secured together upon formation of the outer
grippable core whose material flows into certain ribbed network compartments
and
secures the interlocking parts together.
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US patent No. 5,850,663 granted on December 22"d, 1998 to Hardy et al.
describes an ergonomic handle for a spreading tool designed to permit and
encourage the user to grasp the handle with his/her fore and middle fingers
extended onto the blade. The extended fingers are fully supported by an arch
in
the head of the handle, which combined with its comfortable gripping portion
for
the palm, thumb, ring and little fingers, allows proper alignment of the wrist
and
increased leverage on the blade while working the tool, yet minimizes fatigue,
pain and the potential for injury.
None of the above-mentioned patents disclose or suggest an ergonomic
drywall knife which is inherently lightweight due to its design and whose
blade is
mounted onto the handle without the use of fasteners, while enabling
comfortable
and multiple hand gripping and displaying a long-lasting logo.
Summary of the invention
A main object of the present invention is to provide a drywall knife which
satisfies some of the above-mentioned needs.
In accordance with the invention, the above object is achieved by a drywall
knife, said drywall knife comprising:
a handle having an elongated inner core comprising a longitudinal axis, a
transverse axis, a front end, a rear end and first and second opposite
surfaces
extending from the rear end to the front end of the inner core along the
longitudinal axis thereof; and
a blade securely mounted to the front end of the inner core;
the improvement wherein:
the inner core of the handle comprises rows of recesses extending along
the first surface of the inner core each of said recesses having an opening
facing
said first surface so as to reduce the overall weight of the drywall knife,
said
recesses further defining a set of intersecting ribs shaped, positioned and
sized
so as to ensure rigidity of the handle while maintaining said reduced overall
weight of the drywall knife, and
said inner core further comprises a lid hingedly mounted to the first surface
of the inner core, said lid being positioned and sized to be folded about an
axis
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parallel to the longitudinal axis of the inner core so as to cover said rows
of
recesses, the inner core with the lid in folded position being covered with a
covering material so as to facilitate hand gripping of the drywall knife.
Preferably, the front end of the inner core is provided with a slit extending
along the transversal axis of the inner core. The slit preferably comprises
two
shoulders extending parallel to the longitudinal axis of the inner core and
defining
an insertion slot into which the blade of the drywall knife is securely
inserted. The
blade of the drywall knife preferably consists of a thin plate having an edge
provided with a fishbone comprising tooth edges. The fishbone is devised to be
inserted into the insertion slot at the front end of the inner core so that
when the
fishbone is inserted into the slot, the tooth edges grip into the shoulders
and
prevent the blade from being removed from the inner core of the drywall knife.
This preferred feature permits to mount the blade onto the handle without the
use
of fasteners.
Preferably also, the front end of the inner core is preferably slanted onto
the blade in such a manner that a user of the drywall knife can rest his or
her
hand onto the front end of the inner core and onto the blade in a
substantially flat
manner. Moreover, the inner core preferably comprises a first finger support
portion adjacent the front end of the handle on one of the first and second
opposite surfaces of the inner core for supporting at least one extended
finger of
the user's hand holding the drywall knife. Preferably also, the inner core
further
comprises a second finger support portion adjacent the front end of the handle
on
the other one of the first and second opposite surfaces for supporting at
least one
other extended finger of the user's hand. Preferably also, each finger support
portion respectively comprises two finger-shaped recessed cavities, each
finger-
shaped recessed cavity being used for optionally supporting a user's finger
when
holding the drywall knife. The above-mentioned features are primarily intended
to
allow for a more comfortable hand grip and also to enable various hand grips
of
the drywall knife. This gives to the drywall knife an ergonomic handle
enabling
comfortable and multiple hand gripping.
Preferably also, the second surface of the inner core of the handle is
provided with a protuberance comprising an outer surface having at least one
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groove in the shape of a sign. Preferably also, the second surface further
comprises at least one channel leading within the inner core to the at least
one
groove, such that when the inner core is covered with the covering material,
the
outer surface of the protuberance is not covered by the covering material and
5 thus remains visible and the at least one channel and the at least one
groove of
the second surface of the inner core are both filled-up with the covering
material
to produce the at least one sign on the outer surface of the protuberance of
the
second surface. The sign on the protuberance of the second surface is
preferably
selected from a group consisting of names, words, numbers, logos, trademarks
and symbols conveying information. This feature permits to manufacture the
handle by a molding process which is capable of producing a sign on the handle
of the drywall knife while the handle is molded, the sign lasting all
throughout the
working life of the drywall knife handle.
According to another aspect of the present invention, there is also provided
a drywall knife comprising:
a handle having an elongated inner core comprising a longitudinal axis, a
transverse axis, a front end, a rear end and first and second opposite
surfaces
extending from the rear end to the front end of the inner core along the
longitudinal axis thereof; and
a blade securely mounted to the front end of the inner core;
the improvement wherein:
the inner core of the handle comprises rows of recesses extending along
the first surface of the inner core, each of said recesses having an opening
facing
said first surfaces so as to reduce the overall weight of the drywall knife,
said
recesses further defining a set of intersecting ribs shaped, positioned and
sized
so as to ensure rigidity of the handle while maintaining said reduced overall
weight of the drywall knife,
said inner core further comprises a lid hingedly mounted to the first surface
at the inner core, said lid being positioned and sized to be folded about an
axis
parallel to the longitudinal axis of the inner core so as to cover said rows
of
recesses, the inner core with the lid in folded position being covered with a
covering material so as to facilitate hand gripping of the drywall knife;
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5a
the front end of the inner core is slanted onto the blade in such a manner
that a user of the drywall knife can rest his or her hand onto the front end
of said
inner core and onto said blade in a substantially flat manner;
the inner core comprises a first finger support portion adjacent the front
end of the handle on one of said first and second opposite surfaces of the
inner
core for supporting at least one extended finger of a user's hand holding the
drywall knife;
the inner core comprises a second finger support portion adjacent the front
end of the handle on the other one of said first and second opposite surfaces
for
supporting at least one other extended finger of the user's hand,
each finger support portion respectively comprising two finger-shaped
recessed cavities;
the inner core with the lid in folded position is covered with a covering
material so as to facilitate hand gripping of the drywall knife, said inner
core being
covered with said covering material in such a manner that each finger support
portion is left uncovered; and
the front end of the inner core is transversely wider than the rear end.
The invention and its advantages will be better understood by reading the
following non-restrictive description of a preferred embodiment thereof, made
with
reference to the accompanying drawings.
Brief description of the drawings
Figure 1 is a perspective view of the ergonomic drywall knife according to
a preferred embodiment of the invention.
Figure 2 is a side elevational view of the drywall knife shown in Figure 1
being held by the hand of a user according to a first preferred hand grip.
Figure 3 is a top plan view of the drywall knife shown in Figure 1 being
held by the hand of a user according to a second preferred hand grip.
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Figure 4 is an exploded view of the second end and the blade of the drywall
knife shown in Figure 1.
Figure 5 is a perspective top view of the inner core of the handle of the
drywall knife shown in Figure 1, said inner core being shown with the lid
open.
Figure 6 is a perspective view of what is shown in Figure 5.
Figure 7 is a perspective view of what is shown in Figure 6, the inner core
being shown with the lid closed thereon.
Detailed description of a preferred embodiment of the invention
In the following description, the same numerical references refer to similar
elements. Moreover, although the present invention was primarily designed for
a
drywall knife, it could be used With other types of tools and/or objects of
different
fields, e.g. with putty knives, paint scrapers, drywall saws, ping-pong
rackets, etc.,
as apparent to a person skilled in the art. For this reason, expressions such
as
"drywall knife" and/or "blade" and any other references and/or other
expressions
equivalents thereto should not be taken as to limit the scope of the present
invention and include all other objects with which the present invention could
be
used.
The ergonomic drywall knife 1 according to the preferred embodiment of the
invention shown in the accompanying drawings comprises a handle 3 having an
elongated inner core 5 comprising a longitudinal axis 7, a transverse axis 9,
a front
end 11, a rear end 13 and first and second opposite surfaces 15, 17 extending
from the rear end 13 to the front end 11 of the inner core 5 along the
longitudinal
axis 7 thereof. The drywall knife 1 further comprises a blade 19 securely
mounted
to the front end 11 of the inner core 5.
In accordance with the inivention, the inner core 5 of the handle 3 comprises
at least one recess 21 having an opening facing the first surface 15 so as to
reduce the overall weight of the drywall knife 1, and the inner core 5 further
comprises a lid 23 hingedly mounted to the first surface 15 of the inner core
5, the
lid 23 being positioned and sized to be folded about an axis 25 parallel to
the
longitudinal axis 7 of the inner core 5 so as to cover the at least one recess
21.
_._....~,__._. _ .._ ._ __ _. _ ...
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Preferably, the inner core 5 is made of one single material. Preferably also,
the inner core 5 is obtained through molding in such a manner that the front
end
11, rear end 13, first and secorid opposite surfaces 15, 17, and lid 23 are
integral
to one another, that is, are macie of a single piece. It is worth noting
however that
the lid 23 and/or any other ccimponent of the inner core 5 may be operatively
affixed to the latter by other suitable means, such as fasteners for example,
as
apparent to a person skilled iri the art, without departing from the scope of
the
present invention. For illustrative purposes thereof only, the lid 23 may be
mounted to the inner core 5 by means of an actual hinge, for example.
As better shown in Figures 5 to 7, the front end 11 of the inner core 5 is
preferably provided with a slit 27 extending along the transversal axis 9 of
the
inner core 5. The slit 27 preferably comprises two shoulders 29 extending
parallel
to the longitudinal axis 7 of the inner core 5 and defining an insertion slot
31 into
which the blade 19 of the drywall knife 1 is securely inserted.
As better shown in Figures 1 to 4, the blade 19 of the drywall knife 1
preferably consists of a thin plate 33 having an edge 35 provided with a
fishbone
37 comprising toothed edges 39. The fishbone 37 is devised to be inserted into
the
insertion slot 31 at the front end 11 of the inner core 5 so that when the
fishbone
37 is inserted into the slot 31, the toothed edges 39 grip into the shoulders
29 and
prevent the blade 19 from being removed from the inner core 5 of the drywall
knife 1.
It is worth noting that the handle 3 and blade 19 could also be secured to
one another by other suitable rneans if need be, as apparent to a person
skilled in
the art, such as fasteners, insert-molding of the handle 3 onto the blade 19,
press
fitting, or friction retention, for example.
As better shown in Figure 4, the edge 35 of the blade 19 whose fishbone 37
is inserted into the insertion slot 31 of the front end 11 is preferably the
rear edge
opposite to the front edge of the blade 19, the latter being primarily used
for
contacting a work surface (not shown). It is worth noting however that the
edge 35
whose fishbone 37 is inserted into the insertion slot 31 need not necessarily
be
opposite to the working edge, and may be adjacent thereto for exampCe, as
apparent to a person skilled in the art. The edge 35 is preferably provided
with an
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extruded reinforcement 41. The extruded reinforcement 41 preferably encases
the
edge 35 so as to stiffen the blade 19 transversely while allowing longitudinal
flexibility. The extruded reinforcement 41 may be attached to the blade 19 by
any
suitable means, such as welding, riveting, or swaging for example. Preferably
also,
the blade 19 is made of steel and the extruded reinforcement 41 is made of
aluminium.
As better shown in Figures 2 and 3, the front end 11 of the inner core 5 is
preferably slanted onto the blade 19 in such a manner that a user of the
drywall
knife 1 can rest his or her hand 43 onto the front end 11 of the inner core 5
and
onto the blade 19 in a substantially flat manner. This is primarily intended
to allow
for a more comfortable hang grip of the drywall knife 1.
As better shown in Figures 5 to 7, the inner core 5 preferably comprises a
first finger support portion 45 adjacent the front end 11 of the handle 3 on
one of
the first and second opposite surfaces 15, 17 of the inner core 5 for
supporting at
least one extended finger 47a of a user's hand 43 holding the drywall knife 1.
Preferably also, the inner core 5 further comprises a second finger support
portion
49 adjacent the front end 11 of the handle 3 on the other one of the first and
second opposite surfaces 15, 17 for supporting at least one other extended
finger
47b of the user's hand 43.
In the preferred embodirrient of the invention, the inner core 5 with the lid
23
in folded position is covered with a covering material 51 so as to facilitate
hand
gripping of the drywall knife 1. The inner core 5 is in use covered with the
covering
material 51 in such a manner that each finger support portion 45, 49 is left
uncovered, as better shown in Figures 1, 3 and 4.
It should be understood that although the covering material 51 offers
several advantages which are discussed hereinbelow, the drywall knife 1
according to the present invention could adequately be used without the use of
a
covering material 51, as apparent to a person skilled in the art. However, it
is
believed that the covering material 51 offers a better and more comfortable
hang
grip of the drywall knife 1.
Preferably, each finger support portion 45, 49 respectively comprises two
finger-shaped recessed cavities 53, each finger support portion 45, 49 being
used
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preferably for alternatively supporting the user's index and middle fingers
respectively. More particularly, the same two index and middle fingers 47 of a
user's hand 43 can either rest against the finger-shaped recessed cavities 53
of
the first finger support portion 45 or those of the second finger support
portion 49
so as to operate the drywall knife 1. Furthermore, the drywall knife 1 is
preferably
symmetrical so as to allow the drywall knife 1 to be operated by a left-hand
person
or a right-hand person. Moreover, as better shown in Figures 2 and 3, the
present
invention enables various hang grips of the drywall knife 1 such that the at
least
one finger 47a and the at least one other finger 47b may be respectively the
user's
thumb and index fingers 47, as better shown in Figure 3. For example, as
illustrated in Figure 3, the user's index may rest against a recessed cavity
53 of the
first finger support portion 45 vuhile his or her thumb rests on the recessed
cavity
53 which is diametrically located on the second finger support portion 49.
Moreover, the handle 3 and finger support portions 45, 49 are preferably
designed
to suggest to unexperienced users the various hang grips which may be adopted
so as to ensure proper handling and operating of the drywall knife 1.
According to another embodiment of the invention and as better shown in
Figures 6 and 7, the second surface 17 of the inner core 5 of the handle 3 is
provided with a protuberance 55 comprising an outer surface 57 having at least
one groove 59 in the shape of' a sign 61. Preferably also, the second surface
17
further comprises at least one channel 63 leading within the inner core 5 to
the at
least one groove 59, such that when the inner core 5 is covered with the
covering
material 51, the outer surface 57 of the protuberance 55 is not covered by the
covering material 51 and thus i-emains visible and the at least one channel 63
and
2EI the at least one groove 59 of the second surface 17 of the inner core 5
are both
filled-up with the covering material 51 to produce the at least one sign 61 on
the
outer surface 57 of the protuberance 55 of the second surface 17, as better
shown
in Figure 1. The sign 61 on the protuberance 55 of the second surface 17 is
preferably selected from the group consisting of names, words, numbers, logos,
trademarks and symbols conveying information.
Preferably, the inner core 5 is made of polypropylene and the covering
material 51 is made of santoprene, and preferably also, the inner core 5 has a
CA 02334425 2001-02-06
colour different from that of the covering material 51 so that the sign 61
produced
forms a visual contrast with the protuberance 55 of the second surface 17 of
the
inner core 5.
As better shown in Figure 5, the recess 21 preferably comprises two rows
5 each having preferably seven recesses and each row preferably extends along
the
longitudinal axis 7 of the inner core 5. However, it should be understood, as
apparent to a person skilled in the art, that there could be several recesses
21 and
that these recesses 21 need not necessarily extend parallel to the
longitudinal axis
7 of the inner core 5. As also better shown in Figure 5, the at least one
recess 21
10 with openings facing the first surface 15 preferably form a set of
intersecting ribs
62, thereby allowing a substantially hollow inner core 5 so as to reduce the
overall
weight of the drywall knife 1 while providing the latter with adequate
mechanical
properties. It is worth mentioning that the intersecting ribs 62 need not
necessarily
be orthogonal to one another, and may take on any other various shapes, sizes,
and patterns, as apparent to a person skilled in the art, so as to provide the
inner
core 5, and thus the handle 3, with an adequate longitudinal, transversai, and
torsional rigidity, while maintainiing a reduced overall weight of the drywall
knife 1.
As better shown in Figure 6, the lid 23 is preferably provided with a
protuberance 65 having an outer surface 67. The outer surface 67 is preferably
not
covered by the covering material 51, as better shown in Figure 3.
As better shown in Figures 5 to 7, the rear end 13 of the inner core 5
preferably comprises a hole 69 extending through the inner core 5 from the
first
surface 15 to the second surface 17 thereof. The hole 69 is preferably not
covered
by the covering material 51, as better shown in Figures 1 and 3. This hole 69
may
be used to hang the drywall kriife 1 onto a suitable attachment, as apparent
to a
person skilled in the art.
Preferably, the front end 11 of the inner core 5 is transversely wider than
the rear end 13, as better shown in Figures 5 to 7.
As may now be appreciated, the present invention is a substantial
improvement over the drywall knives known in the art. Firstly, the ergonomic
drywall knife 1 according to the invention is advantageous in that it is
inherently
lightweight due to its design. The row of recesses 21 and lid 23 assembly of
the
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inner core 5 enable to reduce the overall weight of the handle 3. Furthermore,
unlike most of the drywall kniives known in the art, the present invention, as
explained earlier, comprises a blade 19 which is mounted onto the handle 3
without the use of fasteners, thereby reducing manufacturing parts, assembling
steps, and production costs. Another substantial improvement of the present
invention over the drywall knives known in the art is that the handle 3 of the
present invention is an ergoriomic rubberized one enabling comfortable and
multiple hand gripping to maximize gripping effort, reduce hand fatigue and
give
total hand protection. Indeed, the ergonomic rubberized handle 3 maximizes
grip
and reduces hand fatigue. Furthermore, the recessed curves give total hand
protection. Moreover, the built-.in cavities 53 allow maximum gripping effort
and
comfort. Finally, the recessed fiinger angles maximize flexibility and
control.
Of course, numerous modifications could be made to the above-described
embodiments without departing the scope of the invention as defined in the
appended claims.
