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United States Patent 5,953,821
September 21, 1999
Folding tool, such as foldable
knife AbstractA folding tool including a U-shaped handle and
a tool element adapted to lie within the handle in its closed
position, a tang at one end of the tool element fitted pivotally
around a pivot axis between the two prongs of the handle,
said pivot axis extending parallel to the plane defined by
the tool element, wherein a locking leg extending parallel
to the prongs is resiliently suspended on the inner side of
the first prong such that a free end of the leg can be pressed
towards the first prong against the action of a spring force.
The locking leg is provided with locking means adapted to
engage with an engagement part of the tang for locking the
tool in its 180.degree. opened position, the locking state
being disengaged by pushing the free end of the locking leg
towards the first prong.
Inventors: Imagical Design
Appl. No.: 900093 Filed: July 25, 1997 U.S. Class: 30/161;
30/155 Intern'l Class: B26B 001/04 Field of Search: 30/155,160,161,340,342,344
References Cited [ReferencedBy]
U.S. Patent Documents557818 Apr., 1896 Hotchkiss 30/161. 701686
Jun., 1902 Day 30/161. 971057 Sep., 1910 Luce 30/161. 1397018
Nov., 1921 Priestman 30/155. 4066514 Jan., 1978 Penman 30/161.
4083110 Apr., 1978 Goldin et al. 30/155. 4536959 Aug., 1985
Ross 30/161. 4730394 Mar., 1988 Sonner, Jr. 30/161. 4947551
Aug., 1990 Deisch 30/161. Foreign Patent Documents 95799 Apr.,
1897 DE 30/161. 100 224 Apr., 1912 DE 30/161. Primary Examiner:
Payer; Hwei-Siu Attorney, Agent or Firm: Bachman & LaPointe,
P.C.
Claims
1. A folding tool comprising
a U-shaped handle and a tool element adapted to lie within
the handle in its closed position, a tang at one end of the
tool element being fitted pivotably around a pivot axis between
a first prong and a second prong of the handle, said pivot
axis extending parallel to the plane defined by the tool element,
wherein a locking leg extending parallel to the prongs is
resiliently suspended on the inner side of the first prong
such that a free end of said leg can be pressed towards said
first prong against the action of a spring force, said locking
leg being provided with locking means adapted to engage with
an engagement part of the tang for locking the tool in its
180.degree. opened position, the locking state being disengageable
by pushing the free end of the locking leg towards said first
prong.
2. The tool of claim 1,
wherein the locking means comprise an elongated slit formed
in the locking leg and facing the second prong.
3. The tool of claim 1,
wherein the tool element is a bladed knife.
4. The tool of claim 1,
wherein the tool element is a bladed knife having a blade
with one longitudinal cutting edge facing the second prong.
5. The tool of claim 1,
wherein the longitudinal backside edge of the tool element
comprises a straight part extending from the pivot axis in
the direction away from the tang, and wherein the locking
leg is provided with a complementary straight part which during
closing snugly fits with the straight part of the tool element,
said straight part of the tool element being sharp-edged to
provide a guillotine action.
6. The tool of claim 1,
wherein the locking leg is biased in the direction of the
second prong.
7. The tool of claim 1,
wherein a slide is guided and arranged on the first prong
gear the free end of the locking leg, said slide being slidable
along the first prong from a first to a second position and
vice versa, in the first position the slide being arranged
in the interspace between the locking leg and first prong
to hinder the pressing of the locking leg towards the first
prong, in the second position the slide being arranged outside
said interspace allowing said pressing.
8. The tool of claim 1,
wherein the locking leg is formed by folding back an elongation
of the first prong.
9. The tool of claim 1,
wherein the pivot axis is arranged near the outer ends of
the prongs and at a distance from the free outer end of the
tang.
10. The tool of claim 1,
wherein the pivot axis is arranged at a distance from the
free outer end of the tang, such that in the closed position
the tang projects from the handle.
11. The tool of claim 10,
wherein on the one hand the upper and/or lower edge of the
tang and on the other hand that part of the respective neighbouring
prong extending between the pivot axis and the free outer
end of the prong are shaped such that during rotation of the
tool element a guillotine or plier action is provided therebetween.
12. The tool of claim 1,
wherein said part of the tang for locking the tool in its
180.degree. opened position is arranged on the side of the
tang facing the first prong and is provided with a first engagement
edge for engagement with the locking means, said locking means
being provided with a complementary shaped second engagement
edge.
13. The tool of claim 12,
wherein the second engagement edge is arranged at the free
end of the locking leg.
14. The tool of c1aim 12,
wherein the second engagement edge is formed by the end face
of the free end of the locking leg.
15. The tool of claim 12,
wherein said part of the tang is multi-lateral and centered
around the pivot axis.
16. The tool of claim 15,
wherein said part of the tang is square.
17. The tool of claim 12,
wherein said part of the tang is multi-lateral and wherein
the locking means comprise a cutout, the enclosing inner edge
of which forms the complementary shaped second engagement
edge.
18. The tool of claim 17,
wherein said part of the tang is square.
19. The tool of claim 1,
wherein the tang is provided with a slot in which the tool
element is slotted in a releasable manner.
Description
BACKGROUND OF THE INVENTION
This invention relates to a folding tool comprising a U-shaped
handle and a flat tool element adapted to lie within the handle
in its closed position and being pivotable around an axis
into an open position. The pivot axis extends parallel to
the plane spaned by the flat tool element and between the
prongs of the handle. Such folding tools, especially in the
form of foldable bladed knifes, are generally known, see for
example U.S. Pat. Nos. 4,083,110 and 1,397,018. For locking
the bladed knife in its open position, the U-shaped handle
is fabricated from resilient materiel, such that a spring
force resulting from the resilient material must be overcome
on order to increase the distance between the prong ends.
As will be clear, such a spring fore can be used to provide
a locking engagement between the prongs and the tang ot the
knife blade. According to U.S. Pat. No. 1,397,018 said locking
engagement ia possible by employing a handle with an internal
rounded or U-shaped groove in which the tang edges can engage.
Such a locking mechanism is also used in U.S. Pat. No. 4,083,110,
see especially FIG. 3. One of the problems encountered with
such foldable bladed knifes is that the prong ends must be
pushed away from each other in order to disengage the locking
and to be able to bring the bladed knife back into its closed
position. This is difficult, if not impossible, to accomplish
with one hand.
SUMMARY OF THE INVENTION
Briefly described the invention is concerned with a folding
tool of the type comprising a U-shaped handle and a tool element
adapted to lie within the handle in its closed position, a
tang at one end of the tool element being fitted pivotably
around a pivot axis between the two prongs of the handle,
which pivot axis extends parallel to the plane defined by
the essentially flat tool element. One object of this invention
is to provide an improved folding tool of the aforementioned
type. A further object of this invention is to provide a folding
tool of the aforementioned type which can be operated easily
by one hand. Another object of this invention is to provide
a folding tool, which is inexpensive to construct and manufacture.
A still further object of this invention is to provide a folding
knife with a U-shaped handle and an essentially flat knife
blade. A further object of the invention is to provide a folding
tool having a reliable locking mechanism, of which the locking
force can, if necessary, be increased by means of the operating
hand. A folding tool which is especially easily to operate
by one hand is according to the invention obtained by providing
a locking leg extending parallel to the prongs, which locking
leg is resiliently suspended on the inner side of the first
prong such that a free end of said leg can be pressed towards
said first prong against the action of a spring force, and
in which said leg is provided with locking means adapted to
engage with an engagement part of the tang for looking the
tool in its 180.degree. open position, the locking state being
disengageable by pushing the free end of the locking leg towards
said first prong. The locking leg can easily be manipulated
by means of a finger of the hand gripping or enclosing the
U-shaped handle. The locking leg can be manipulated even without
loosening the grip on the U-shaped handle. If the U-shaped
handle is gripped very tightly, for example the prongs of
the U-shaped handle being pressed towards each other, this
will possibly increase the force needed for disengaging the
locking state, but it will not make the disengaging impossible
because the locking leg is virtually independent from the
prongs by means of its suspension. A locking mechanism which
is reliable in function, and easily to construct, is obtained
by providing the locking leg with an elongated slit facing
the second prong. The elongated slit can take up or enclose
a side edge of the tang of the tool element. This elongated
slit can in the same manner also provide fog a locking in
the closed position, in which case the elongated slit will
take up a part of the tool element. By providing a bladed
knife as the tool element, a very functional foldable bladed
knife is obtained according to the invention. A foldable bladed
knife, which is easy and safe to use, is according to the
invention obtained if the tool element is a bladed knife having
a blade with at least one longitudinal cutting edge at the
side of the second prong. In use, the thumb of the hand gripping
the unfolded foldable knife is resting on the upper or first
prong. To disengage the locking mechanism of the bladed knife,
it is only necessary to squeeze between the thumb and a further
finger, for example the index finger, the first prong and
the free end of the locking leg. If desired also at the side
of the first prong a cutting edge can be provided so that
a double edged cutting blade is obtained. A very advantageous
guillotine effect is obtained if the longitudinal backside
edge of the tool element comprises a straight part extending
from the rotational axis in the direction away from the tang,
and if the locking leg is provided with a complementary straight
part which during closing and/or in the closed position snugly
fits with the straight part of the tool element, and if the
straight part of the tool element is sharp-edged to provide
a guillotine action. This sharp-edged feature could also be
obtained by a cutting edge, or example if a double edged cutting
blade is used. In order to improve the locking mechanism,
it is further advantageous if the locking leg is biased in
the direction of the second prong, such that in the locking
state the engagement between the locking leg and the tang
of the tool element is more solid and firm. In order to be
able to further improve the engagement and locking between
the locking leg and the tang, it is according to the invention
very advantageous if a slide is guided and arranged on the
first prong near the free end of the locking leg, said slide
being slidable along the first prong from a first to a second
position and vice versa, in the first position the slide being
arranged in the interspace between the locking leg and first
prong to hinder the pressing of the locking leg towards the
first prong, in the second position the slide being arranged
on a place, for example outside said interspace, allowing
said pressing. With such an embodiment, the slide can be moved
to its first position, after which the engagement and locking
can be improved by squeezing the prongs of the handle by means
of the hand in which the handle is held. By means of the slide
it is assured that the squeezing action on the prongs is transferred
to the locking leg and thus is utilized for improving the
locking and engagement between the locking leg and the tang.
This slide also restricts sideways movement of the locking
leg. Also other means are conceivable for improving the engagement
and locking by arranging a distance member in the interspace
between the locking leg and the first prong. In order to reduce
the manufacturing costs it is according to the invention advantageous
if the locking leg is formed by folding back an elongation
of the first prong. In this manner the locking leg and the
handle can be made out of one piece of preferably a resilient
material. The resistance against bending moments exerted on
the knife blade or flat tool element and thus also the locking
of the locking mechanism is further improved if the rotational
axis is arranged near the outer ends of the prongs and at
a distance from the free outer end of the tang. By increasing
the distance between the free outer end of the tang and the
rotational axis, resistance to the bending moment is increased.
In order to increase the efficiency of use, it is according
to the invention advantageous if the rotational axis is arranged
at a distance from the free outer end of the tang, such that
in the closed position the tang projects from the handle.
By this it becomes possible to open the folding tool by pushing
the projected tang against a further object, such as a table
top, a stone, a leg, etc. A simple, effective and reliable
locking mechanism is obtained if said part of the tang for
locking the tool in its 180.degree. opened position is arranged
on the side of the tang facing the first prong and is provided
with a first engagement edge for engagement with the locking
means, said locking means being provided with a complementary
shaped second engagement edge. In this way a locking having
a so-called positive fit is obtained. Advantageously thc second
engagement edge is arranged at or near the free end of the
locking leg. According to a special embodiment the second
engagement edge can be formed by the end face of the free
end of the locking leg. An advantageous positive fit is to
be obtained if said part of the tang is multi-lateral, preferably
square, and centered around the pivot axes. This provides
the possibility to lock the tool element in intermediate positions
between its closed and 180.degree. opened position. In case
of a square part, there is provided a locking possibility
in a 90.degree. opened position. According to a further preferred
embodiment the positive fit is improved if said part of the
tang is multi-lateral, preferably square. and if the locking
means comprise a cutout, the enclosing inner edge of which
forms the complementary shaped second engagement edge. Other
objects, features and advantages of the present invention
will become apparent upon reading the following specification,
when taken in conjunction with the accompanying drawings.
These drawings show some preferred embodiments.
BRIEF DESCRIPTION OF THE
DRAWINGS
FIG. 1 is a schematic side view of a foldable knife according
to the invention, showing the blade of the knife in its 180.degree.
opened position. FIG. 2 is a schematic side view of a second
embodiment of a foldable knife according to the invention,
showing the blade or the knife in its 180.degree. opened position.
FIG. 3 is a schematic side view of still a further embodiment
of a foldable knife according to the invention, showing the
blade of the knife in its closed position. FIGS. 4 and 4A
are schematic perspective views of still further embodiments
of a folding tool according to the invention, in which the
tool element (not shown) is exchangeable.
DESCRIPTION OF SOME PREFERRED
EMBODIMENTS
Throughout the several figures alike parts are indicated by
alike reference signs. FIG. 1 illustrates a first embodiment
of a folding tool, in casu a foldable knife, according to
the invention. The tool comprises a U-shaped handle 1 having
two prongs 2 and 3. An essentially flat tool element, in casu
a bladed knife 4, is adapted to lie within the handle 1 in
its closed position, as is indicated by dashed dotted lines.
At one end of the bladed knife 4 is provided a tang 5. This
tang 5 is fitted pivotally around a pivot axis 6 between the
two prongs 2, 3 of the handle 1. The pivot axis 6 extends
parallel to the plane defined by the bladed knife 4, in this
case extends through the plane defined or spanned by the bladed
knife 4. The pivotally fitting of the tang between the two
prongs of the hand1e is realized by means of two pivot pins
7. Those pivot pins 7 are in the form of screws. Referring
to FIGS. 2 and 3 it will, however, be clear that the pivot
pin can also be provided in a different way, for example by
means of a screw bolt 8 with a nut 9, or rivet (not shown).
As far as described up to now with respect to the drawings
the folding tool does not essentially differ from folding
tools, especially foldable knives, known from the prior art.
According to the invention the folding tool is provided with
a locking leg 10. In the embodiment according to FIG. 1 the
locking leg 10 is fixed, for example welded or riveted, to
the first or upper prong 2 near its base side 11 opposite
its free end. The locking leg 10 is made of a resilient material,
such that when it is pressed upwardly (arrow A) towards or
against the upper prong a resilient reactive force is introduced.
Near its free end 12 the locking leg 10 is provided with an
aperture through which the upper pivot pin 7 essentially freely
extends. On its side opposing the lower or second prong 3
the locking leg 10 is provided with locking means in the form
of a slanting part 20 having an elongated slit 13, which in
this case in fact is a throughgoing slit which is also open
on the upper side of the locking leg 10 facing towards the
upper prong 2. As will be clear from FIG. 1, the knife blade
4 can be brought in a locking state, in which the upper backside
of the tang 5 is engaged within the elongated slit 13. It
will also be clear that by pressing the locking leg 10 upwardly,
as is indicated by arrow A, in the direction of the upper
prong 2, the locking state will be disengaged, so that the
knife blade 4 can be rotated over 180.degree. back to its
closed state, indicated by dashed dotted lines. By making
the part 20 of the locking leg 10 slanting or angled and having
the upper side of the tang 5 essentially straight, a guiding
effect is obtained, which helps to bring the knife blade in
its locking state. A similar guiding affect can of course
be obtained by providing the tang with a slanting protrusion
21 and having the locking leg 10 essentially straight (see
FIG. 3) or by providing both the tang and the locking leg
with a slanting part. On its lower side the knife blade 4
is provided with an ordinary longitudinal cutting edge 14
lying at the side of the second or lower prong 3. During use
the hand of a user will enclose the handle 1 and the thumb
of the user will, at least when cutting, normally rest on
the upper prong 2 near the pivot pin 7. In order to disengage
the locking state it suffices to push with the index finger
against the underside of the locking leg 10 in the direction
of the arrow A. As will be clear this can be done with one
and the same hand holding the knife during use and essentially
without altering the grip of the knife. The same index finger
can after disengaging the locking mechanism be used to push
against the backside of the tang 5 in order to rotate the
knife blade 4 out of its 180.degree. opened position. Next
the knife blade 4 can easily be turned further to its closed
position, in which the knife blade 4 lies within the handle
1, in which contact with the cutting edge 14 is prohibited.
In order to lock the knife blade in its closed state (the
dashed dotted lines), one can make use of the same principle
as is used for the locking in its 180.degree. opened position.
For this purpose the same slit 13 or a further slit (not shown)
can be used. FIGS. 2 and 3 show two further embodiments, which
especially differ by the shape of the locking leg 10. The
locking legs 10 according to FIGS. 2 and 3 are formed by folding
back an elongation of the first or upper prong 2. This will
be clear from the Figures. This provides the possibility to
manufacture the handle 1 and locking leg 10 out of one piece
of for example a resilient metal. A spacer element 22 can
be arranged between the prong and locking leg near the place
of the folding back. FIG. 2 further shows a slide 15 being
slidably arranged on the upper prong 2. The slide 15 can upon
manipulation by means of a finger slide from a first position
(dotted lines) to second position (solid lines) and vice versa.
In the first position, the slide lies in the interspace between
the locking leg and first prong and can, if desired, contact
both, so that pressing of the locking leg towards the first
prong (in the direction of arrow A) is prohibited. In this
first position the locking engagement between the locking
leg 10 and the upper backside of the tang 5 is increased and
can further be increased by squeezing the upper prong 2 and
lower prong 3 between the one hand gripping the tool during
use. In order to be able to disengage the locking state, first
the slide 15 has to be moved to its second position, then
the locking leg 10 can be pushed upwardly and the knife 4
can be rotated back to its closed position. Also other means
are conceivable for improving the engagement and locking by
arranging a distance member in the interspace between the
locking leg and the first prong. FIG. 3 shows a third embodiment
of a foldable knife according to the invention in its closed
state. The free outer end of the tang 5 projects in this closed
state from the handle, such that the knife blade can easily
be rotated by striking or pressing with said projecting free
outer end against an object, such as a table or a rock. Further
referring to FIG. 3, the third embodiment shows a knife blade
4 with a longitudinal backside edge comprising a straight
part 16 extending from the rotational axis 6 in the direction
away from the tang 5. The locking leg 10 is provided with
a complementary straight part. As shown in FIG. 3 the straight
parts 16 and 17 snugly fit with each other, when the tool
is in its closed state or closed position. Further the straight
part 16 of the knife blade 4 is essentially sharp-edged. With
the term "sharp-edged" is meant that this edge 16
is essentially not rounded but has sharp corner edges, so
that when the knife blade 4 is brought into its closed position
there is provided a guillotine effect between the straight
part 16 and the straight part 17 enabling to cut through for
example a piece of paper It will be clear that this also provides
for the possibility to cut through a rope, a cable, etc. For
cutting through a rope or cable there could further be provided
a small cutout or recess in the locking leg 10 in which the
cable or rope can be accommodated during the closing of the
knife blade 4 so that its position is fixed during the cutting
through. Further referring to FIG. 3, this embodiment shows
an alternative for the locking of the knife blade into its
closed position. The locking leg 10 io provided with two protruding
bulges 23 (only one of them is to be seen) between which the
knife blade is enclosed in its closed position. FIG. 4 shows
a schematic perspective view of a folding tool according to
the invention. This folding tool comprises a U-shaped handle
31 having an upper prong 32 end a lower prong 33 and a locking
leg 40 which is mounted on the upper prong 32 in a manner
alike the locking leg 10 of the embodiment according to FIG.
1. Between the ends of the prongs 32 and 33 extends a pivot
axis 39 around which the tang 35 is rotatable by means of
pivot pins 37. The upper pivot pin 37 is at its base provided
with a multi-lateral part, in this case a square part 34.
This square part 34 in fixed relative to the tang 35 and centered
on the pivot axis 39. At its free end the locking leg 40 is
provided with an engagement edge, the so-called second engagement
edge. The first engagement edge is formed by the vertical
sides of the square part 34. The second engagement edge 36
is essentially complementary shaped with each side of the
square part 34. It will be clear from FIG. 4 that in case
of engagement between engagement edge 36 and one of the sides
of engagement edge 34 a so-called positive fit is obtained.
This positive fit can be disengaged by pressing the locking
leg 40 in the direction of the upper prong 32. Upon this disengagement
of the positive fit, the tang 35 can be rotated to its desired
position. It will be clear that by virtue of the square part
34 a positive fit is possible after each time the tang 35
is rotated over 90.degree.. By making the multi-lateral part
34 for example hexagonal more locking positions are obtained,
in this case one locking position for each 60.degree. of rotation.
The tang 35 of the embodiment according to FIG. 4 is provided
with a cavity 38 in which a tool element can be slid. This
so-called slotting connection between the tang 35 and the
tool element (not shown in FIG. 4) provides for an easy manner
to interchange between different tool elements. In such a
case there will be provided for a non-permanent fixation between
the tool element and the tang 35. It will also be possible
to provide for a permanent fixation between the tool element
and the tang 35, in which case the embodiment according to
FIG. 4 still provided the advantage that many different kinds
of foldable tools can be manufactured with a minimum of standard
parts. FIG. 4A is similar to FIG. 4 wherein the locking means
comprise a cutout 42 formed in the locking leg 40, the enclosing
inner edge of which forms the complementary shaped second
engagement edge. While the invention has been described in
detail with particular reference to three preferred embodiments
thereof, it will be understood that variations and modifications
can be effected within the spirit and scope of the invention
as described herein before and as defined in the appended
claims. For example it will be clear that if in its closed
position the tang extends beyond the ends of the prongs, said
extending part of the tang can be provided with a further
tool, such as for example a screw driver blade, a bottle opener,
a can or tin opener, a cross-head screw driver tip, etc. The
so-called guillotine effect can of course also be obtained
between the sharp knife side of a knife blade and the neighbouring
prong as well as between the tang and one or both prongs.
Further the tool element can be pivoted in two directions.
It will also be clear that the handle can be provided with
extra features, such as a wooden or plastic grip part. Even
if the handle and prongs are made very stiff, a good functioning
of the folding tool according to the invention is still possible
by virtue ot the separate locking leg.
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