Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to hand tools with foldout blades, and, more
particularly, to such hand tools with multiple foldout locking blades.
Hand tools with multiple deployable blades have long been known
and used in the home, in the workplace, and in sporting applications. A
folding
pocket knife having two blades is an example. The blades are carried inside
a handle for storage, and are selectively opened, one at a time, when required
to perform specfic functions.
Pocket knife-like devices, such as those produced by Wenger and
Victorinox and commonly called "Swiss Army" knives, use this same principle
extended to a plurality of tools carried within the body of the knife on axles
located at either end of the knife. Such implements typically incorporate a
variety of types of blade-type tools" such as one or more sharpened blades,
a screwdriver, an awl, a file, a bottle opener,' a magnifying glass, etc.
Generally, Swiss Army knives are designed to be sufficiently small and tight
for carrying in a pocket and are therefore limited as to the strength and
robustness of their structure.
In recent years, devices known generically as "combination tools"
have been developed and widely marketed. Such combination tools typically
include a jawed mechanism such as a pliers or a scissors, and deployable
handles having implements pivotally folded into the handles. The implements
may include slot screwdrivers, Phillips-head screwdrivers, knife blades, can
openers, awls, and the like. The implements are folded into the handles for
storage or when the jaw mechanism is to be used, and pivoted open as
necessary. Designs and features of combination tools have been extensively
patented. Combination tools are available commercially from a number of
manufacturers, such as Buck Knives, SOG, Leatherman, and Gerber. These
combination tools are used by a variety of persons, such as repairmen,
outdoorsmen, handymen, and hobbyists. The combination tools, while of
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about the same size, are mechanically more robust than the multi-bladed
knives generally known as "Swiss Army" knives. The combination tools have
substantial jaw mechanisms, and, at least in some cases, the fold-out
implements may be positively locked into place to avoid unintended closing
and injury to the user.
One useful feature of some conventional folding knives is the
ability to positively lock the blade in the open position to prevent an
unintentional closure during service that could cut the hand of the user.
Lockbacks, sidelocks, axle locks, and other types of locks are known in the
art.
Another useful feature is the biasing of the blade toward its closed position
from angular orientations close to the closed position. Such biasing acts as
a detest to prevent the blade from unintentionally folding open when carried
or when another blade is already open and in use. The blade may also be
biased toward its open position from angular orientations close to the open
position. In either case, the biasing effect gives a secure feel to the
closing
and opening of the blades. Cam, backspring, ball detest, and other types of
biasing structures are known in the art.
Positive locks used in conjunction with biasing structures are
desirable features of knives, and have recently been utilized in knives having
multiple blades rotating in the same direction on a common axle. (When the
term "blade" or "blade tool" is used herein in reference to deployable tools
received into the handle of a combination tool, knife or other type of tool,
it
refers to any relatively thin tool that is folded into the handle, regardless
of the
utilization of the tool. Such a "blade" therefore includes, but is not limited
to,
a sharpened knife blade, a serrated blade, a screwdriver, an awl, a bottle
opener, a can opener, a saw, a file, etc.) Existing approaches have internal
structures that require a great deal of space when adapted for use on several
side-by-side blades, or the locking release controls take up too much space
or are inconvenient. For example, a typical combination tool has three, four
or more blades folding from a common axle in each handle, where the width
of the handle -the required envelope size within which the entire structure
must fit -is on the order of about 1 inch or less. The sides of the handle,
the
blades, and any locking and biasing mechanism must fit within that width, and
an externally accessible lock releasing structure must also fit on the outside
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of the handle within that width. If the width of the handle of the hand tool
is
increased significantly above about 1 inch, the combination tool will no
longer
be comfortable in the hand.
There is a need for an approach to locking and biasing mukiple,
side-by-side blades of combination tools, knives, and other types of hand
tools
where the blades pivot on a common axis. The present invention fulfills this
need, and further provides related advantages.
The present invention provides a hand tool wherein multiple
blades pivot on a single axle. The blades are each positively locked into
their
open positions by a single locking mechanism. The blades are also biased
toward their closed positions and their open positions. When one blade is
opened, the others stay in their closed positions. The opened blade is
positively locked and later unlocked without moving the other blades from
their
closed positions. In a preferred form of the invention, the hand tool is a
handle
of a combination tool having a pair of handles deployably joined to a jaw
mechanism. The combination tool embodying the invention is suited for
attachment to a key ring or the like, but is also permits the use of a nut-
grasping feature in a pliers head. The handles are sculpted for comfortable
grasping during service. The handles are provided with convenient detents in
the closed and open positions.
In accordance with the invention, the hand tool comprises a tool
body having a pair of oppositely disposed sides, an axle extending
transversely between the sides of the body at one end of the tool body, and
a plurality of blades supported on the axle. Each blade includes a base having
a peripheral surface and an implement extending outwardly from the blade
base, and further has a bore through the blade base with the axle extending
through the bore so that the blade base and thence the blade is rotatable on
the axle between a closed position wherein the blade is contained within the
tool body and an open position wherein the blade extends from the tool body.
There is a notch in the peripheral surface of the blade base. A locking
mechanism is slidably movable relative to the axle and includes a locking bar
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that engages the notch of the blade base when the blade is in the open
position. The locking mechanism further includes means for biasing the
locking bar into engagement with the peripheral surface of the blade base,
wherein the biasing means comprises a portion of the tool body.
There is, additionally, means for biasing one of the blades toward
the open position while biasing all others of the blades toward the closed
position. This biasing means preferably takes the form of a first cam surface
on the peripheral surface of each blade base at a location adjacent to the
notch, having a first cam maximum surface height and a first cam maximum
surface height angular position, and a second cam surface on the peripheral
surface of the blade base at a location remote from the notch, having a
second cam maximum surface height and a second cam maximum surface
height angular posfion located about 110 to about 120 degrees from the first
cam maximum surface height angular position. The first cam maximum
surface height is preferably about the same as the second cam maximum
surface height.
Thus, the invention provides a lockinglbiasing mechanism that
positively locks any one of the blades into its open position while biasing
the
remaining blades toward their closed positions. The locking mechanism has
a single release that releases the blade that is locked into-the open
position.
As the selected blade is opened or closed against its biasing force, the other
blades remain in their closed positions under the influence of their biasing
forces. Subsequently, a different blade may be selected for opening, with the
same results and performance.
In the preferred form of the invention, the hand tool comprises a
pliers jaw mechanism lying in a jaw mechanism plane. The jaw mechanism
includes a first jaw piece having a first jaw body, a first lug extending
therefrom, and a first jaw piece external lateral surface. The jaw mechanism
also includes a second jaw piece having a second jaw body, a second lug
extending therefrom, and a second jaw piece extemai~lateral surface. The first
jaw piece and the second jaw piece are pivotably joined together to pivot
about
a jaw axis between a first jaw position wherein the jaw pieces are closed
together in a facing relationship, and a second jaw position wherein the jaw
pieces are not closed together. The tool further includes a first handle lying
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in the jaw mechanism plane and pivotabiy engaged by a first handy axle pin
to the first lug. The first handle pivots in the jaw mechanism plane about a
handle axis that is parallel to the jaw axis, between a first handle closed
position wherein the first handle is adjacent to the second jaw piece, and a
first
handle open position wherein the first handle is extended away from the first
jaw piece. The first handle has a first handle external lateral surface having
a dished shape to conform to at least a portion of the second jaw piece
external lateral surface. The hand tool further includes a second handle lying
in the jaw mechanism plane and pivotably engaged by a second handle axle
pin to the second lug. The second handle pivots in the jaw mechanism plane
about a handle axis that is parallel to the jaw axis, between a second handle
closed position wherein the second handle is adjacent to the first jaw piece,
and a second handle open position wherein the second handle is extended
away from the second jaw piece. The second handle has a second handle
external lateral surface having a dished shape to conform to at least a
portion
of the first jaw piece external lateral surface.
The first lug and the second lug have facing protrusions thereon
at locations remote from the jaw bodies, adjacent to the pivotable
engagements of the respective handles to the lugs. The protrusions are
dimensioned so that when the jaw pieces are closed together, the tips of the
protrusions overlap. An aperture is thereby defined that may be used to attach
the hand tool to a key ring or the like, independently of the jaw feature so
that
the jaw may be provided with a faceted nut-engaging aperture.
A detest mechanism is desirably provided to urge each handle
toward its respective open or closed position. A detest is distinct from a
lock,
wherein the handle would be positively locked into the open or closed
position.
In the present case, the detest for each handle is defined in relation to the
handle axis. The detest includes a handle cam surface locally defining the
surface of the handle and disposed laterally adjacent to the handle axis. The
handle cam surface includes a closing handle cam surface having a handle
cam surface first distance from the handle axis, an opening handle cam
surface remote from the closing handle cam surface and at about the handle
cam surface first distance from the handle axis, and an intermediate handle
cam surface disposed between the closing handle cam surface and the
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opening handle cam surface and being a handle cam surface second distance
from the handle axis, wherein the handle cam surface second distance is less
than the handle cam surface first distance. The handle cam surface second
distance is from about 0.002 inches to about 0.012 inches less than the
handle cam surface first distance. With this detent mechanism, the lug of the
jaw piece comprises a lug cam rider surface positioned in a facing
relationship
to the handle cam surface and disposed to ride thereon as the handle is
moved between the handle closed position and the handle open position. The
opening handle cam surface terminates in a handle shoulder remote from the
intermediate handle cam surface, and the lug cam rider surface includes a lug
shoulder disposed to engage the handle shoulder when the handle is in the
handle open position.
Other features and advantages of the present invention will be
apparent from the following more detailed description of the preferred
embodiment, taken in conjunction with the accompanying drawings which
illustrate, by way of example, the principles of the invention. The scope of
the
invention is not, however, limited to this preferred embodiment.
The accompanying drawings iilustrate the invention. In such
drawings:
FIGURE 1 is a top plan view of a combination tool embodying the
present invention, with the handles in a closed position;
FIGURE 2 is a top plan view similar to that illustrated in FIG. 1,
illustrating various blades partially or fully extended from the handles;
FIGURE 3 is a top plan view of the hand toot illustrated in FIGS.
1 and 2, with the handles in the open position;
FIGURE 4 is a detail of the area indicated by the number 4 in FIG.
1, illustrating a cam and detent structure for the handles;
FIGURE 5 is a partially fragmented perspective view of a handle
of the combination tool of FIGS. 1-3;
FIGURE 6 is another perspective view of the handle of the
combination tool of FIGS.1-3, wherein a blade has been pivoted into an open
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position, the locking mechanism is shown, and the handle has been inverted
from the view of FIG. 6;
FIGURE 7 is an end view of the handle of FIG. 6 with all blades
pivoted to their closed position, taken generally along the line 7-7 of FIG.
6;
FIGURE 8 is an elevational sectional view taken generally along
the line 8-8 of FIG. 6;;
FIGURE 9 is an elevational view of a blade base;
FIGURE 10 is a perspective view of a locking mechanism housing
including a locking bar designed to engage the blade base;
FIGURES 11A-E are a series of schematic elevationat views of
the operation of the locking and biasing mechanism as the blade is operated,
wherein FIG. 11 A shows the blade in the fully open and positively locked
position, FIG. 11 B shows the blade after manual unlocking but while biased
toward the open position, FIG.11C shows the blade at an intermediate biased
toward the closed position, FIG.11 D shows the blade approaching the closed
position, and FIG. 11 E shows the blade in the closed position;
FIGURE 12 is a schematic elevational view of operation of the
locking mechanism with two blades, one open and positively locked and the
other closed; and
FIGURE 13 is a schematic plan view illustrating a blade in a
closed position within the handle.
As shown in the drawings for purposes of illustration, the present
invention is concerned with a combination tool, generally designated by the
reference number 20. The combination tool 20 includes a jaw mechanism 22
having a first jaw piece 24 and a second jaw piece 26. The first jaw piece 24
and the second jaw piece 26 are pivotably joined together at a jaw pivot 28.
The first jaw piece 24 and the second jaw piece 26' lie in a jaw mechanism
plane. The jaw pivot 28 permits the first jaw piece 24 and the second jaw
piece 26 to pivot between a closed position (as illustrated} with the jaws in
a
facing relationship, and an open position.
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The first jaw piece 24 includes a first jaw body 30 and a first lug
32 extending therefrom. The first jaw piece 24 has an outwardly bowed first
jaw piece external lateral surface 34, whose shape is generally dictated by
the
shape of the first jaw body 30. The second jaw piece 26 includes a second
jaw body 36 and a second lug 38 extending therefrom. The second jaw piece
26 has an outwardly bowed second jaw piece external lateral surface 40,
whose shape is generally dictated by the shape of the second jaw body 36.
The jaw bodies 30 and 36 may define ~ any type of tool with a
jawed pivoting structure. Preferably, as illustrated, the jaw bodies 30 and 36
cooperatively define a pliers with a grasping tip 42 and a faceted nut-
grasping
aperture 44. As will be discussed subsequently, the nut-grasping aperture 44
is not used for attachment of the hand tool to a key ring, and it therefore
may
be furnished with facets useful in grasping a nut or other object. A wire
cutter
48 is formed by regions of reduced thickness adjacent to the nut-grasping
aperture 44. The jaw bodies 30 and 36 could instead cooperatively define
other types of jawed, pivoting structures, such as a scissors, a wire
stripper,
or other type of pliers.
A first protrusion 48 extends from the first lug 32 toward the
second lug 38 at a location remote from the ftrst jaw body 30. A second
protrusion 50 extends from the second lug 38 toward the first lug 32 at a
location remote from the second jaw body 36. The first protrusion 48 and the
second protrusion 50 are in a facing relationship to each other and overlap
when the jaw mechanism 22 is closed. When the jaw mechanism 22 is
closed, as illustrated in FIGS. 1-4, the first protrusion 48 and the second
protrusion 50 cooperatively define an aperture 52. When the jaw mechanism
22 is closed and the handles are folded and detented into the closed position,
as in FIG. 1, the aperture 52 is locked closed such that it may be used to
attach the hand tool 20 onto a key ring or other ring.
Two handles 54 and 54' forming channel sections, are deployably
connected to the jaw mechanism 22. The first handle 54 is pivotably engaged
by a first- handle axle pin 55 to the first lug 32. The first handle 54 rnay
thereby pivot in the jaw mechanism plane between a first-handle closed
position illustrated in FIGS. 1 and 2, where the first handle 54 lies
immediately
adjacent to the second jaw piece 26, and a first-handle open position
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illustrated in F1G. 3, where the fin;t handle 54 is extended away from the
first
jaw piece 24 and the second jaw piece 26.
The first handle 54 has a first-handle external lateral surface 56
with a dished shape 58. The dished shape 58 serves two purposes. When
the first handle 54 is pivoted to the closed position as illustrated in FIGS.
1 and
2, the dished shape 58 closely conforms to the second jaw piece external
lateral surface 40, so that there is a close fit between the first handle 54
and
the second jaw piece 24. This close fit permits the combination tool 20 to be
compact in its closed state. When the first handle 54 is pivoted to the open
position as illustrated in FIG. 3, the dished shape 58 provides a sculpted
grip
that is comfortable to hold and allows the user to apply a substantial force
to
the jaw mechanism.
The second handle 54' is pivotably engaged by a second-handle
axle pin 55' to the second lug 38. The second handle 54' may thereby pivot
in the jaw mechanism plane between a second-handle closed position
illustrated in FIGS. 1 and 2, where the second handle 54' lies immediately
adjacent to the first jaw piece 24, and a second-handle open position
illustrated in FIG. 3, where the second handle 54' is extended away from the
first jaw piece 24 and the second jaw piece 26.
The second handle 54' has a second-handle external lateral
surface 56' with a dished shaped 58'. The dished shape 58' serves the same
purposes as the dished shape 58 of the first handle 54, discussed above.
A desirable feature of the combination tool 20 is the ability to
controllably retain the handles 54 and 54' in the open position or the closed
position with a mild retention force that initially resists movement away from
the respective position but then is overcome with sufficient force so that the
handle may be rotated. This mechanism is generally termed a "detent"
mechanism. A detent mechanism is distinct from a positive lock which must
be unlocked before the handle can be pirroted. The closing detent mechanism
holds the handles in the closed position so that they do not unintentionally
open in the pocket of the user and also so that the aperture 52 does not
unintentionally open when it is retained to a key ring. The opening detent
mechanism holds the handles in the open position so that the user of the tool
may conveniently operate the jaw mechanism. Many detent mechanisms are
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known in the art, but some are relatively expensive and others are structured
so that, if the hand tool were scaled to a small size, the detent mechanism
would be too small and fragile to be practical.
Both handles 54 and 54" are provided with a detent structure, and
only one will be described in detail with the understanding that the other is
identical. FIG. 4 illustrates the detent mechanism for the first handle 54. In
FIG. 4, the axle pin 55 is removed to reveal a first pivot aperture 60 through
the first handle 54.
The end of the first handle 54 adjacent to the first pivot aperture
60 is locally contoured to form a first-handle cam surface 62 which is
disposed
laterally adjacent to the first pivot aperture fi0. The first-handle cam
surface
62 has three separate but continuous regions. A closing first-handle cam
surface 64 is positioned at a first distance R, from the first pivot aperture
60.
An opening first-handle cam surface fib is remote from the closing first-
handle
cam surface 64 and generally spaced about 165 degrees away from the
closing first-handle cam surface 64. The opening first handle cam surface 66
is positioned at a second distance R2 from the first pivot aperture 60. The
value of R2 is about the same as the value of R, in the preferred embodiment.
An intermediate first-handle cam surface 68 is disposed between the closing
first-handle cam surface 64 and the opening first-handle cam surface 66. The
intermediate first-handle cam surface 68 is positioned at a third distance R3
from the first pivot aperture 60. The difference between the values of R9 and
R, determines the force required to move the first handle 54 from the
intermediate position to the closed position, and the difference between the
values of R3 and R2 determines the force required to move the first handle 54
from the intermediate position to the open position. The value of R3 is less
than the value of R, and R2, by an amount of from about 0.002 inches to
about 0.012 inches, and most preferably by an amount of about 0.008 inches.
These relative values may be selected to produce the desired closing and
opening force characteristics.
A "back" side 70 of the opening first-handle cam surface 66,
remote from the intermediate first-handle cam surface 68, is positioned at a
fourth distance R4 from the aperture fi0. A "back" side 72. of the closing
fist-
handle cam surface 64, remote from the intermediate first-handle cam surface
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68, is positioned at a fifth distance RS from the aperture 60. The value of R4
is less than the value of RZ, and the value of RS is less than the value of
R,.
The greater the difference between the value of R4 and R2, the greater the
retention force holding the handle 54 in the open position. The greater the
difference between the value of R, and R5, the greater the retention force
holding the handle 54 in the closed position. The differences are preferably
from about 0.002 inches to about 0.012 inches, and most preferably about
0.004 inches.
The shapes of the cam surfaces 64, 66, 68, 70, and 72, and the
transitions between the cam surfaces 64 and 68, and between the cam
surfaces 66 and 68, may be relatively gradual or more steeply inclined,
depending upon the exact nature of the detesting force that is desired. In the
embodiment of FIG. 4, the side of the cam surface 64 remote from the cam
surface 68 is relatively steeply inclined at an incline surface 74 having an
angle of about 30 degrees to the local radius. The transition between the cam
surfaces 66 and 68 is gradual, and no relatively narrow point of transition
can
be easily identfied.
The first lug 32, which is pivotably joined to the first solid body
handle 54 at the first pivot aperture 60 (by the first handle axle pin 55),
has a
first-lug cam rider surface 76 positioned in a facing relationship to the
first-
handle cam surface 62. The first-lug cam rider surface 76 rides along the
first-
handle cam surface 62 as the first handle is rotated between the first-handle
closed position and the first-handle open position. When the first handle 54
is in or rotationally near its closed position as illustrated in FIGS. 1 and
2, the
interfering cam relationship tends to urge the first handle 54 toward the
closed
position. When the first handle 54 is in or rotationally near its open
position
as illustrated in FIG. 3, the interfering cam relationship tends to urge the
first
handle 54 toward the open position. In both cases, the urging force can be
overcome by rotational force applied by the user. The previously discussed
shape of the cam surface 62 is selected so that the 'required rotational force
is sufficiently large so as to pravide a sufficient retaining or detesting
force, but
not so large that the required force to overcome the detest is uncomfortable
for the user. The differences between the values of R, and RZ, on the one
hand, and value of R3, on the other, determines the force required to move the
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handle 54 to the respective closed or open position. A difference value of
about 0.008 inches has been found to provide the best compromise between
these competing considerations. The shape of the intermediate first-handle
cam surface 68 may be selected to give any desired "feel" to the opening and
closing motion. Preferably, the intermediate first-handle cam surface 68 is of
approximately constant distance fram the aperture 60 from near the closing
first-handle cam surface 64 and near the opening first handle cam surface 66
so that the force required to rotate the handle 54 through this region is
approximately constant to provide a smooth rotational feel for the user.
The closing caroming action is provided by the contact between
the first-lug cam rider surface 76 and the closing first-handle cam surtace
64.
The relatively steep inclination angle, preferably about 30 degrees, of the
first-
lug cam rider surface 76 is selected to provide a positive retention detenting
force in the closed position yet also produce a distinct and controlled
spacing
S, between the first handle 54 and the first lug 32, and a distinct and
controlled spacing S2 between the dished shape 58 of the first handle 54 and
the second jaw piece external lateral surface 40, when the first handle 54 is
in the closed position as shown in FIG. 4. In one preferred embodiment, S,
is about 0.005 inches and S2 is about 0.010 inches. This design approach
produces a face of the combination tool with a close spacing between the
handles and the jaw mechanism, so that the face is substantiaify continuous
and coplanar. Secondly, when the combination tool is manufactured, there
are inevitably small dimensional variations. During the service life of the
tool,
the mechanism may wear with repeated use. The described approach of the
relation between the first-lug cam rider surface 76 and the closing first-
handle
cam surface 64 results in retention of a smooth caroming action and a close
fit, as exemplified by the values of S, and S2, both initially and after
extended
service.
A first-handle stop shoulder 78 is preferably provided at the end
of the opening first-handle cam surface 66 remote from the intermediate first-
handle cam surface 68. A cooperating first-lug stop shoulder 80 is provided
at the end of the ftrst-handle 54. 'UVhen the first handle 54 is pivoted to
the
open position, the stop shoulders 78 and 80 contact each other to limit the
extent of rotation. When the first handle 54 and the second handle 54' are
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grasped to operate the jaw mechanism 22, the grasping force is reacted
through the shoulders 78 and 80, providing a strong, secure grip.
In the combination tool 20 and those available commercially, it is
common practice to affix a plurality of blade tools 82 in each of the handles
54
and 54' to increase the utility of the combination tool. The blade tools 82
are
pivotably connected by a tool pivot axle 84 to the handles 54 and 54' at the
ends remote from the pivot pins 55 and 55'. Each of the blade tools 82 can
be closed to lie within the channel sections of the handles 54 and 54' or
opened to extend from the respective handle to perform their function or
positioned at an intermediate position, as shown in FIG. 2. When the term
"blade" or "blade tool" is used herein in reference to deployable tools
received
into the handle of the combination tool or other type of tool, it refers to
any
relatively thin tool that is folded into the handle, regardless of the
utilization of
the tool. Such a "blade" therefore includes, but is not limited to, a
sharpened
knife blade, a serrated blade, a screwdriver, an awl, a bottle opener, a can
opener, a saw, a fife, etc. This terminology is used to distinguish the tool
folded into the handle from the overall hand tool, in this case of the
combination tool 20.
The combination tool 20 has at least two, and more typically thn~e
or more of the blade tools 82 arranged on the axle 84 of each handle 54 and
54', as seen in FIGS. 2 and 5 for the case of three blade tools 82a, 82b, and
82c, all of which open in the same rotational direction. FIG. 5 also shows the
channel-shaped section of the handle 54, having two sides 86a and 86b and
a web 88 connecting the two sides 86a and 86b. The tool pivot axle 84
extends between the two sides 86a and 86b.
In the preferred approach, one of the sides 86a has a cut-down
region 90 to permit easy manual access to the blade tools 82 when they are
to be opened. The blade tools 82 are arranged so that the longest of the
blades 82c is adjacent to the side 8fib which is not cut-down, and the
shortest
of the blades 82a is adjacent to the side 86a having a cut-down region 90.
FIG. 6 illustrates the handle 54 in a view inverted from the FIG. 5
and with one of the blade tools 82c opened by rotating it on the pivot axle
84.
In normal use, only one of the blade tools 82 is opened at a time, with the
others remaining closed and within the handle 54. If the generally flat blade
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tools 82 were positioned too closely adjacent to each other in a touching
contact, as is the case in some commercially available combination tools, the
friction between the touching surfaces of adjacent blade tools would tend to
cause a blade tool to be unintentionally dragged open as one of the other
blade tools was intentionally opened. In the present approach, illustrated in
FIG. 7, a washer 92, is placed between each pair of blade tools 82 and
between the last blade tool on the axle and the interior of the side 8fi of
the
handle 54. Because the width dimension D of the handle 54 is typically small,
on the order of about'/Z inch, conventional thick metal washers are preferably
not used. Instead, the washer 92 is preferably made of a polymeric material,
most preferably polypropylene, polyethylene, or polytetrafluoroethylene
(Teflon), about 0.010 inch thick. Such washers can be prepared economically
by a cutting or stamping process on a sheet of Teflon adhered to a substrate
carrier with a pressure-sensitive adhesive, to produce annular washer shapes.
The individual washers are peeled off the substrate carrier and affixed to the
opposite sides of the blade tools 82 overlying a bore 94 through which the
tool
pivot axle 84 passes. The washer may also be obtained as a separate article
and assembled with the blade tools 82 and the axle. In another approach, the
washer may be formed as a raised annular area of the blade tool surrounding
the bore 94.
FIG. 8 shows a preferred form of the locking and biasing
mechanism. The blade tool 82 includes a blade base 96 and an implement
98 extending outwardly from the blade base 96. The implement may be any
generally flat, operable type of implement such as a sharpened knife blade
(as illustrated), a serrated blade, a screwdriver, an awl, a bottle opener, a
can
opener, a saw, a file, etc. The implement 98 is preferably integral with the
blade base 96, although it can be made detachable.
The blade base 96, shown in greater detail in FIG. 9, is generally
flat and thin, on the order of about 0.05 to about 0.20 inches thick, and
includes the bore 94 extending therethrough and the washer 92 around the
bore. (The blade bases of the various blade tools need not be of the same
thicknesses). The tool pivot axle 84 extends through the bore 94. The blade
base 96 is laterally bounded generally on three sides by a peripheral surface
100, and contiguous with the implement 98 on the fourth side. The peripheral
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surface 100 includes a generally straight-sided, flat-bottomed nc~trch 9D2.
Immediately adjacent to the notch 102, on the side remote from the implement
98, is a first cam surface 104. More remote from the notch 102 is a second
cam surface 106. The first cam surface 104 is characterized by a first cam
maximum surface height measured as a maximum distance to the peripheral
surface 100 along a radius from the center of the bore 94 of C1 and passing
through the first cam surface 104. The second cam surface 106 is
characterized by a second cam maximum surface height measured as a
maximum distance to the peripheral surface 100 along a 'radius from the
center of the bore 94 of C2. In the preferred approach, C2 is approximately
the same as C1, and in the preferred embodiment on the order of
approximately 0.220 inches. The height of the peripheral surface is reduced
between the first cam surface 104 and the second cam surface 106. In a
preferred embodiment, the first cam maximum surface height of the first cam
surface 104 is positioned about 6 degrees away from the adjacent edge of the
notch 102. The second cam maximum surface height of the second cam
surface 104 is positioned about 118.5 degrees from the first cam maximum
surface height.
FIG.10 illustrates a locking mechanism 108 which, when properly
positioned over an end 110 of the handle 54 opposite its connection to the jaw
mechanism 22, is movable relative to the tool pivot axle 84 to releasably lock
the blade tools 82 supported therein in the open position. The locking
mechanism 108 includes a lock housing 112 which is positionable on the tool
handle 54 and which provides a locking bar 114 capable of engaging the notch
102 of the blade base 96 when the blade is in the open position, and a lock
disengagement pad 116 opposite the locking bar 114. The lock housing
further includes a pair of oppositely disposed elongated apertures 118 which
slidably receive therein ends of the toot pivot axle 84. The locking mechanism
108 performs its function in connection with a cantilevered end section 120 of
the web 88 which serves to bias the locking bar 114 'rnto engagement with the
peripheral surtace 100 of the blade base 96.
More particularly, the lock housing 112 is situated on the tool
handle 54 to be slidabie relative to the tool pivot axle 84 such that the end
120
of the web 88 contacts the locking bar 114 to urge it into engagement with the
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peripheral surface 100 of the blade base 96. When a selected blade tool 82
is rotated from the closed position into the open position, the locking bar
114
is confcgured to seat within the notch 102 and thereby prevent the blade tool
82 from being counterrotated back into its closed position without the locking
bar 114 first having been displaced from the notch 102. This is accomplished
by applying a force to the lock disengagement pad 118 toward the handle 54
and in the direction of the locking bar 114. Application of such a force
causes
slidable movement of the lock housing 112 relative to' the tool pivot axle 84
to
remove the locking bar 114 from the notch 102 against the biasing force of the
end section 120 of the web 88. With the locking bar 114 disengaged from the
notch 102, the blade tool 82 may then be rotated from its open position to the
closed position within the handle 54. In the absence of a force applied to the
disengagement pad 116, the end 120 of the web 88 exerts a constant biasing
force against the locking bar 114 that maintains the locking bar in engagement
with the peripheral surface 100 of the blade base 96.
Additionally, as can best be seen in FIG. 9, there is desirably a
shoulder 122 on the implement 98 that is in facing relation to a terminal end
124 of the web 88. This engagement of the shoulder 122 to the end 124
provides an additional interference restraint of the blade tool 82 that
resists
rotation of the implement 98 past its fully open position. This additional
restraint is particularly valuable where the implement 98 is of a type where
it
is forced in such a direction during service, such as a blade having a
sharpened edge that is forced downwardly during cutting operations. The
blade tool 82 is preferably dimensioned so that there is a gap of about 0.005
inches between the shoulder 122 and the end '124 of the web 88 when no load
is applied to the blade tool. When a sufficient load is applied to produce a
0.005 inch deflection, the shoulder 122 contacts the end 124 to stop any
further movement.
FIGS.11A through 11 E depict the operation of the lockinglbiasing
mechanism in a series of views as a single blade tool 82 is moved from the
open and positively locked position (FIG. 11A) to the closed and biased closed
position {FIG.11 E). In FiG.11A, the blade tool 82 is open, and the locking
bar
114 is received into the notch 102, forming a positive lock of the blade tool
82
into the open position.
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In FIG. 11 B, the lock disengagement pad 116 has been
depressed to push the locking bar 114 out of the notch 102, and the user of
the tool has manually rotated the blade in a counterclockwise direction by
about 10 degrees. The blade tool 82 remains biased toward the open
position, because the locking bar 114 rests against the sloping cam surface
104a that slopes back toward the notch 102.
After only a slight additional rotation of the blade tool 82 in the
counterclockwise direction, FIG. 11 D, the locking bar 914 has passed the
first
cam maximum surface height location 104b and is contacting the portion of
the first cam surface 104c that slopes away from the notch 102. If the blade
tool 82 is released at this point, it tends to move toward the closed position
rather than the open position.
Further counterclockwise rotation of the blade tool 82 brings the
locking bar 114 into contact with the second cam surface 106 as shown in
FIG. 11 D. An additional counterclockwise rotation of the blade tool 82 brings
the locking bar 114 into contact with the portion 106a of the second cam
surface 106 that slopes toward the closed position and thereby biases the
blade 82 toward the closed position, as shown in FIG. 11 E. The blade 82 is
thereby forced toward the closed position and retained there. To move the
blade 82 away from the closed position, as shown in of FIG. 11 E and back
toward the orientation of FIG. 11 D requires that the user manually overcome
the bias force resulting from the reaction of the locking mechanism 108 and
its locking bar 114 against the cam surface 106a.
A comparison of the effects on the blade tool 82 of the reaction
between the locking bar 114 and the peripheral surface of the blade base 96
in FIGS. 11A and 11 E illustrates the difference between "positive locking" of
the blade tool and "biasing" of the blade tool. in FIG. 11A, the reception of
the
locking bar 114 into the notch 102 provides a positive lock from which the
blade tool 82 cannot be moved by the application of any ordinary manual force
to the blade tool 82. Intentional release of the positive lock by manually
pressing the pad 116 is required in order to move the blade tool 82 from its
positively locked position. On the other hand, the biasing of the blade tool
82
toward a position, illustrated for the biasing toward the closed position in
FIG.
11 E, is produced in the preferred embodiment by a cam action which can be
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readily overcome with ordinary manual force on the blade tool. This
distinction
befinreen positive locking and biasing is important. Biasing is readily
achieved
for blade tools 82 in a confined space, but positive locking is difficult to
achieve
in a confined space such as that available in a typical combination tool
wherein several blade tools are supported in a narrowly confined space in
each handle.
One feature of the present approach is that the blade tool selected
for opening and use is positively locked into the open position, while the
remaining blade tools that have not be selected remain biased toward their
closed position. This feature is illustrated in FIG. 12, which superimposes
views of an open and posi~vely locked blade tool 82 and a closed and biased
closed blade tool 82'. At the same time that the locking bar 114 is received
into the notch 102 of the positively locked blade tool 82, the locking bar 114
rests against the slope 104a of the second cam surface 104' of the biased
closed blade tool 82'. The locking bar 114 both positively locks the blade
tool
82 open and biases the blade tool 82' closed. The same bias-closed effect is
operable for all of the blade tools which are not open and in use. In a
typical
case wherein there are three blade tools such as shown in FIGS. 2 and 5-7,
there is a single blade tool 82 which is open and positively locked and two
blade tools 82' which are biased closed.
A further feature is that the blade tool 82' remains biased toward
the closed position as the blade tool 82 is opened and closed. At an
intermediate stage of rotation of the blade tool 82 between its closed and
open
positions, the locking bar 114 continues to rest against the slope 104a' of
the
second cam surface 104' of the closed blade tools 82', biasing them toward
the closed position. The closed blade tools 82' therefore do not
unintentionally
open as the intentionally opened blade tool 82 is rotated. With this camming
approach, there may be a small range of the rotation of the blade tool 82 (as
the locking bar 114 passes over the top of the second cam 104) where the
locking bar 114 is raised off the slope 104a' to release the biasing of the
blade
tools 82' toward the closed position. This small range of release of biasing
is
not noticeable to most users of the combination tool as they close or open the
blade tool 82 in a smooth motion, and for most orientations of the tool.
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Most of the discussion of the rotation of the blade tools in relation
to FIG.11 has been in regard to the closing of the pn:viously opened blade
tool
82. The present approach provides an advantage when the selected blade
tool 82 is being opened as well. If FIG. 13 is viewed as one moment during
the opening of the selected blade tool 82 (i.e., clockwise rotation of the
blade
tool 82), the biasing force of the locking bar 114 on the cam surfaces 104a'
tends to retain the other blade tools 82' in the closed position. The
cooperation of this biasing action on the blade tools 82' and the use of the
washers 92 to reduce the frictional forces between the blade tool 82 that is
being manually rotated and the blade tools 82' which are to remain closed
causes the blade tools 82' to either remain in the fully closed position or to
rotate back to the fully closed position after a small rotation away from the
fully
closed position. Thus, the user of the tools is afforded the convenience of
opening, positively locking, later manually unlocking, and closing any of the
selected blade tools while the others of the blade tools are automatically
retained in the closed position.
Although a particular embodiment of the invention has been
described in detail for purposes of illustration, various modifications and
enhancements may be made without departing from the spirit and scope of
the invention. For example, although the lockinglbiasing mechanism has been
discussed in relation to the blade tools of the combination tool 20, it is
equally
applicable to other hand tools which have openable blade tools. Accordingly,
the invention is not to be limited except as by the appended claims.
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