DOUBLE-ENDED DUAL-MECHANISM RETRACTABLE BLADE UTILITY KNIFE

COUTEAU UNIVERSEL A LAMES RETRACTABLES, A DEUX MECANISMES D'ACTIONNEMENT ET A DEUX EXTREMITES UTILES

English Abstract

A double-ended dual mechanism retractable blade utility knife (10). The knife
(10) includes two separately actuable mechanisms
(382, 386) which allow extension and retraction of one or both blades (28, 34)
independently of one another. The cutting surfaces (30, 31)
of the respective blades (28, 34) are oriented towards opposite sides of the
knife (10), thereby facilitating rotation of the knife (10) within
the user's hand in order to change which blade (28, 34) is currently being
used. The independent nature of the dual mechanisms allows
both of the blades (28, 34) to be held in the extended position. A storage
area (72) is further provided behind each of the mechanisms for
the storage of spare blades (29).

French Abstract

Couteau universel (10) à lames rétractables, à deux mécanismes d'actionnement et à deux extrémités utiles, qui possède deux mécanismes d'actionnement (382, 386) séparés permettant l'extension et la rétraction d'une ou des deux lames (28, 34) indépendamment l'une de l'autre. Les surfaces de coupe (30, 31) des lames (28, 34) respectives sont orientées vers des côtés opposés du couteau (10), ce qui facilite la rotation du couteau (10) dans la main de l'utilisateur, selon la lame (28, 34) que ce dernier veut utiliser. L'indépendance des deux mécanismes entre eux permet le maintien simultané des deux lames (28, 34) dans la position étendue. En outre, une zone de réserve (71) située derrière chacun des mécanismes est destinée au stockage de lames de rechange (29).

Claims

9
What is claimed is:
1. A double-ended dual-mechanism retractable blade utility knife,
comprising:
a housing having a longitudinal axis;
a first blade having a first cutting surface;
a second blade having a second cutting surface;
first blade carrier means for carrying the first blade and for sliding along
the
longitudinal axis of the housing; and
second blade carrier means for carrying the second blade and for sliding
along the longitudinal axis of the housing;
wherein the first and second blade carriers slide along the longitudinal axis
of the housing independently of one another such that the first and second
blades
may be extended in opposite directions;
wherein the first cutting surface of the first blade is positioned on a first
side of a
longitudinal plane which is perpendicular to a side surface of the blades; and
wherein the second cutting surface of the second blade is positioned on a
second
side of the longitudinal plane which is perpendicular to a side surface of the
blades.
2, The utility knife of claim 1, further comprising:
a first space formed in the housing adjacent the first blade carrier means,
the first space sized to allow storage of first spare blades; and
a second space formed in the housing adjacent the second blade carrier
means, the second space sized to allow storage of second spare blades.
3. The utility knife of claim 1, wherein each of the first and second blade
carrier means comprise:
a first portion shaped to engage a blade and to prevent relative movement
between the first portion and the blade along the longitudinal axis.

4. The utility knife of claim 3, wherein each of the first and second blade
carrier means further comprise:
a flexible arm coupled to the first portion; and
a tab formed on a distal end of the flexible arm;
wherein the tab engages indentations in the housing which limit travel of
the blade carrier along the longitudinal axis.
5. A double-sided dual mechanism retractable blade utility knife, comprising:
a housing having a longitudinal axis;
a first blade having a first cutting surface;
a second blade having a second cutting surface;
first blade carrier means for carrying the first blade and for sliding along
the
longitudinal axis of the housing;
a first space formed in the housing adjacent the first blade carrier, the
first
space sized to allow storage of first spare blades;
second blade carrier means for carrying the second bIade and for sliding
along the longitudinal axis of the housing; and
a second space formed in the housing adjacent the second blade carrier, the
second space sized to allow storage of second spare blades;
wherein the first and second blade carriers slide along the longitudinal axis
of the housing independently of one another such that the first and second
blades
may be extended in opposite directions; and
wherein the first cutting surface of the first blade is positioned on a first
side of a
longitudinal plane which is perpendicular to a side surface of the blades; and
wherein the second cutting surface of the second blade is positioned on a
second
side of the longitudinal plane which is perpendicular to a side surface of the
blades.
6. The utility knife of claim 5, wherein each of the first and second blade
carrier means comprise:
a first portion shaped to engage the blade and to prevent relative movement
between the first portion and the blade along the longitudinal axis.

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7. The utility knife of claim 6, wherein each of the first and second blade
carrier means further comprise:
a flexible arm coupled to the first portion; and
a tab formed on a distal end of the flexible arm;
wherein the tab engages indentations in the housing which limit travel of
the blade carrier along the longitudinal axis.

Description

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DOUBLE-ENDED DUAL-MECHANISM
RETRACTABLE BLADE UTILITY KNIFE
TECHNICAL FIELD OF THE INVENTION
The present invention generally relates to utility knives and, more
particularly, to
a double-ended dual-mechanism retractable blade utility
knife.
BACKGROUND OF THE INVENTION
Utility knives which incorporate a retractable, replaceable razor blade have
been
popular in many applications for years. There are deficiencies, however, in
the prior
art designs which limit their usefulness in certain applications. For example,
in the
roofing trade it is generally necessary for the roofer to carry two such
utility knives.
One knife is equipped with a straight razor blade for cutting felt paper and
the like,
while the other knife is equipped with a hooked blade for cutting shingles and
the like
which have a granulated surface. Neither of these knives are well adapted for
cutting
the other type of material, therefore it is necessary for the roofer to carry
both types of
knives.
Carrying two knives, however, is inconvenient, especially when working on a
roof. Whenever it is necessary to switch knives, the user must retract the
first blade
and stow the first knife, take out the second knife and extend the second
blade. This is
extremely inconvenient during applications where use of both knives in
alternating
succession is routinely required.
There have been attempts in the prior art to solve this problem. For example,
U.S. Patent No. 5,093,994 to Karas discloses a double-ended utility knife.
This knife,
however, still exhibits most of the problems encountered with using two
separate

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knives. To switch blades, the knife must be turned around, the first blade
must be
retracted and the second blade must be extended. Turning the knife around is
generally a two-handed operation.
There is therefore a need in the prior art for a utility knife that allows use
of two
different blades without requiring the cumbersome manipulations required by
prior art
knives during blade changes. The present invention is directed toward meeting
this
need.

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SUMMARY OF THE INVENTION
The present invention relates to a double-ended dual-mechanism retractable
blade
utility knife. The knife includes two separately actuable mechanisms which
allow
extension and retraction of one or both blades independently of one another.
The
cutting surfaces of the respective blades are oriented towards opposite sides
of the
knife, thereby facilitating rotation of the knife within the user's hand in
order to change
which blade is currently being used. The independent nature of the dual
mechanisms
allows both of the blades to be held in the extended position. A storage area
is further
provided behind each of the mechanisms for the storage of spare blades.
In one form of the invention, a double-ended dual-mechanism retractable blade
utility knife is disclosed, comprising a housing; a first blade carrier
operative to carry a
first blade and to slide along a longitudinal axis of the housing; and a
second blade
carrier operative to carry a second blade and to slide along the longitudinal
axis of the
housing; wherein the first and second blade carriers may be slid along the
longitudinal
axis of the housing independently of one another.
In another form of the invention, a double-sided dual-mechanism retractable
blade
utility knife is disclosed, comprising a housing; a first blade carrier
operative to carry a
first blade and to slide along a longitudinal axis of the housing; a first
space formed in
the housing adjacent the first blade carrier, the first space sized to allow
storage of first
spare blades; a second blade carrier operative to carry a second blade and to
slide along
the longitudinal axis of the housing; and a second space formed in the housing
adjacent
the second blade carrier, the second space sized to allow storage of second
spare
blades; wherein the first and second blade carriers may be slid along the
longitudinal
axis of the housing independently of one another; and wherein a first cutting
surface of
the first blade is positioned on a first side of the longitudinal axis; and
wherein a
second cutting surface of the second blade is positioned on a second side of
the
longitudinal axis.

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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of an exterior of the utility knife of the
present
invention.
FIG. 2A is a side elevational view of an interior of one half of the knife of
FIG. 1.
FIG. 2B is a side elevational view of an interior of a second half of the
knife of
FIG. 1, illustrating the actuation mechanisms.
FIG. 3 is a side elevational view of a blade carrier of the present invention.
FIG. 4 is a side elevational view of the blade carrier of FIG. 3 with a
straight razor
blade mounted thereon.
FIG. 5 is a cross-sectional view of the utility knife of the present
invention.

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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
For the purposes of promoting an understanding of the principles of the
invention,
5 reference will now be made to the embodiment illustrated in the drawings and
specific
language will be used to describe the same. It will nevertheless be understood
that no
limitation of the scope of the invention is thereby intended, such alterations
and further
modifications in the illustrated device, and such further applications of the
principles
of the invention as illustrated therein being contemplated as would normally
occur to
one skilled in the art to which the invention relates.
Referring now to FIG. 1, there is illustrated a first embodiment of the
present
invention, indicated generally at 10.
The two ends of the utility knife 10 are identical, with one end being
inverted
about the longitudinal knife axis with respect to the other end. Therefore,
identical
reference numbers are used herein to denote identical parts, with the suffix
"a" or "b"
added to denote on which end of the knife 10 the part is located.
With reference to FIGS. 2A-B, the utility knife 10 includes two mating housing
halves 12 and 14 which are held together by a transverse threaded fastener 16
which
passes through the hole 18 and threadably engages the hole 20 which is formed
as a
portion of the housing half 14. The two housing halves 12, 14 form a first
open
channe122a in which is located a first actuating lever 24a. Movement of the
first
actuating lever 24a to the left in FIG. 2B causes a first blade (illustrated
in phantom at
28) to be extended from a slot formed in the first end 26 of the utility knife
10. The
first blade 28 includes a first cutting surface 30 facing downward in FIG. 2b.
Conversely, movement of the first actuating lever 24a to the right in FIG. 2B
causes
the first blade 28 to be retracted completely within the housing 10.
Similarly, a second
open channel 22b is formed by the mating housing halves 12, 14 transversely
and
longitudinally opposite from the open channel 22a. A second actuating lever
24b is
disposed within the second open channel 22b and is operative to extend a
second blade
(illustrated in phantom at 34) from an open slot in a second end 36 of the
utility knife

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when the second actuating lever 24b is moved to the right in FIG. 2B. The
second
blade 34 includes a second cutting surface 31 facing upward in FIG. 2b.
Movement of
the second actuating lever 24b to the left in FIG. 2B operates to retract the
second
blade 34 completely within the utility knife 10.
5 Each of the actuating levers 24a and 24b is attached to respective first and
second
blade carriers 38a and 38b, as illustrated in FIG. 2B. Because the
configuration of first
blade carrier 38a is identical to the configuration of second blade carrier
38b, such
configuration is illustrated in FIGS. 3 and 4 without the use of "a" and "b"
suffixes.
For example, reference to blade carrier 38 in FIGS. 3 and 4 should be
understood to
10 apply to both first blade carrier 38a and second blade carrier 38b. An
analogous
numbering scheme is used to refer to the elements in FIG. 5 that are common to
both
the first and second sides of the knife 10. Referring now to FIGS. 3 and 4,
the blade
carrier 38 is preferably formed from metal and includes raised transverse
surfaces 40,
42 and 44 which operate to limit movement in three directions of a blade
28.mounted
thereon (see FIG. 4). Movement of the blade 28 is further prevented by a tab
46 which
fits into a notch 48 formed into the blade 28. The blade 28 has two such
notches 48
which allow for reversing of the blade 28 within the blade carrier 38 for
extended
blade life. The blade 28 is of the type standardly used in this art.
Referring once again to FIGS. 2A-B, the first blade carrier 38a is maintained
in a
retracted position by engagement of a first tab formed on the first end 50a of
the first
blade carrier 38a with a first indentation 52a formed in the housing halves
12, 14.
Similarly, the first blade carrier 38a is maintained in an extended position
by
interaction between the first tab formed on the first end 50a and a second
indentation
54a notch 54 formed in the housing halves 12, 14. The first tab formed on the
first end
50a of the first blade carrier 38a is moved from first indentation 52a to
second
indentation 54a (and vice versa) by depressing the first actuating lever 24a,
which
causes the first arm 51 a to flex, thereby disengaging the first tab formed on
the first
end 50a from the first and second indentations 52a, 54a. Engagement of the
first tab
formed on the first end 50a with the first and second indentations 52a and 54a

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therefore operates to securely maintain the first blade carrier 38a (and hence
the first
blade 28) in either the retracted or extended position.
The second blade carrier 38b is maintained in a retracted position by
engagement
of a second tab formed on the second end 50b of the second blade carrier 38b
with a
third indentation 52b formed in the housing halves 12, 14. Similarly, the
second blade
carrier 38b is maintained in an extended position by interaction between the
second tab
formed on the second end 50b and a fourth indentation 54b formed in the
housing
halves 12, 14. The second tab formed on the second end 50b of the second blade
carrier 38b is moved from third indentation 52b to fourth indentation 54b (and
vice
versa) by depressing the second actuating lever 24b, which causes the arm
second 51b
to flex, thereby disengaging the second tab formed on the second end 50b from
the
third and fourth indentations 52b, 54b. Engagement of the second tab formed on
the
second end 50b with the third and fourth indentations 52b and 54b therefore
operates
to securely maintain the second blade carrier 38b (and hence the second blade
34) in
either the retracted or extended position.
Referring now to the cross-sectional view of FIG. 5, it will be appreciated
that
when the housing halves 12, 14 are coupled together, the blade carrier 38 is
maintained
within a longitudinal sliding track formed by protrusions 56, 58, 60 and 62
formed
integrally with the housing half 12 and by protrusions 64, 66, 68 and 70
formed in the
housing half 14. These protrusions from the housing halves 12, 14 form top and
bottom C-channel tracks in which the blade carrier 38 runs. It will be
appreciated by
those skilled in the art that the exact configuration of such tracks is not
critical to the
present invention, merely that some means for limiting the motion of the blade
carrier
38 be provided within the housing halves 12, 14.
As best illustrated in FIG. 5, an indentation 72 is formed in the housing half
14
behind the blade carrier 38 in order to provide a space for storage of spare
blades 29.
The spare blades 29 may be first blades 28 and/or second blades 34, both of
which will
fit in this storage space. T'he spare blades 29 are stored in an inverted
position as
compared to the blade in the blade carrier 38.

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It will be appreciated by those skilled in the art that the utility knife 10
of the
present invention exhibits several advantages over prior art utility knives.
First, the
utility knife 10 allows independent extension and retraction of two blades.
This is a
particularly desirable feature when two different blades, such as a straight
blade and a
hooked blade, need to be used repeatedly during the same project. A further
advantage
of the dual-mechanism of the utility knife 10 is that it allows the cutting
surfaces 30,
31 of the two blades 28,34 to be oriented in opposite directions. Such an
orientation of
the cutting surfaces 30, 31 facilitates single-handed reorientation of the
utility knife 10
in the user's hand in order to position the other blade for use. Such
reorientation
simply involves rotating the knife in the user's hand about an axis extending
through
the fastener 16. Such a flipping motion is easily accomplished with one hand.
When
both blades 28, 34 are left in the extended position, the user may easily
switch between
blades 28,34 by simply rotating the utility knife 10 with a single hand.
By comparison, the prior art double-ended utility knives required that one
blade
be retracted and the other blade be extended whenever the user desired to
switch to the
other blade. Furthenmore, the cutting surfaces on the prior art double-ended
utility
knives face in the same direction, thereby making it extremely difficult to
reorient the
knife for use with the other end without employing both of the user's hands.
Another
useful feature of the utility knife 10 of the present invention is the
provision of a
somewhat wider handle than is customary in such knives, with the inclusion of
the
cavity 72 behind each blade carrying mechanism which allows for the storage of
spare
blades 29 on both sides of the knife 10. Not only does this increase the
number of
spare blades 29 which may be carried in the knife 10, it also facilitates
carrying spare
blades 29 for both types of blades (e.g. a straight blade 28 and a hooked
blade 34).
While the invention has been illustrated and described in detail in the
drawings
and foregoing description, the same is to be considered as illustrative and
not
restrictive in character, it being understood that only the preferred
embodiment has
been shown and described and that all changes and modifications that come
within the
spirit of the invention are desired to be protected.

Representative Drawing