Cross-Reference to Related Applications
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This application is a continuation-in-part of my
copending patent application entitled "Open End Ratchet
Wrench," Serial No. 09/114,628, filed on July 13, 1998,
which is a continuation-in-part of application Serial No.
09/036,349, filed on March 6, 1998, both of which are
hereby incorporated herein by reference.
Background
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This invention relates to ratchet wrenches, and
more particularly to open-end ratchet wrenches that can
be placed on a workpiece from the side.
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There are many occasions when it is desirable to
apply torque to a workpiece (such as nuts, bolts, and in-line
hydraulic fittings) in order to, for example, rotate
the workpiece with respect to a threaded member. Two
well known tools for rotating workpieces are ratchet
wrenches and open-end crescent wrenches. Ratchet
wrenches are typically close-ended devices that
completely encircle the workpiece and are thus installed
on the workpiece from the top (or bottom, depending upon
the orientation of the workpiece). By contrast, open-end
wrenches can be installed from the side of the workpiece.
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Open-end wrenches are particularly useful in small
spaces where there may only be sufficient room to install
the wrench from the side. Moreover, in confined spaces,
there is often insufficient space to accommodate the
ratchet mechanism of typical close-ended ratchet
wrenches. In addition, open-end wrenches are a must for
tightening/ loosening in-line fittings of hydraulic or
fuel lines, which can only receive a wrench from the
side.
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Typical open-end crescent wrenches lack a ratchet
mechanism. As a result, during a tightening or loosening
operation, the wrench must be removed from the workpiece
after it has rotated the workpiece a relatively small
amount (such as 30 degrees), and then replaced thereon at
a different angle for continued rotation. This procedure
is repeated (often many times) until the workpiece is
completely tightened or loosened.
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Open-end ratchet wrenches that resemble typical
crescent wrenches have been developed for confined and
in-line fitting applications. Some open-end ratchet
wrenches employ numerous spring-loaded rollers, cams, or
pawls for engaging the workpiece; others use an insert
shaped to fit over the workpiece and engage an internal
ratchet mechanism. Some of these wrenches encircle the
workpiece to such an extent that, even though the
wrenches have open ends, they must actually be installed
vertically from above or below the workpiece.
Another open-end ratchet wrench, described in my
U.S. Patent No. 5,456,143, includes a pair of elongated
plates that are pivotally mounted to a pair of spaced
jaws on the wrench handle. A spring mounted on the
handle engages the plates and biases them toward each
other so that the plates grasp and turn the workpiece
when the handle is rotated in a driving direction. The
spring bias is overcome when the handle is turned in the
opposite direction, allowing both plates to pivot on the
jaws and slide over the faces of the workpiece in a
ratcheting manner.
Summary
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This invention features, in a general aspect, a
wrench having a pair of jaws disposed on a handle and
spaced to define an opening for a workpiece, and a pair
of plates each of which includes a workpiece engaging
surface adjacent the opening; the plates are mounted on
the jaws for selective movement between: a) a first
position in which the plates are substantially immobile
with respect to each other so that rotation of the handle
in a first direction causes the plates to grasp the
workpiece between the engaging surfaces and turn the
workpiece in the first direction, and b) and a second
position in which a first one of the plates is pivotable
with respect to a second one of the plates so that
rotation of the handle in a second, opposite direction
causes pivoting of the first plate and allows the
engaging surfaces to slide over the workpiece, thereby
allowing the workpiece to remain stationary. Thus, the
wrench tightens (or loosens) the workpiece when rotated
in the first direction, and slips over the workpiece in a
"ratcheting" manner when rotated in the second, opposite
direction.
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The invention unites features of an open end
wrench and a ratchet wrench in a wrench that is rugged
and simple to make. The wrench has a minimal number of
moving parts and thus is much easier to manufacture (and
repair) than wrenches which use many individual pawls or
rollers to provide ratcheting. In preferred embodiments,
the plates each engage the workpiece over a relatively
large surface area, thereby maximizing torque
transmission and minimizing contact stresses imposed on
the wrench and the workpiece. This reduces the risk of
damage to the wrench and the workpiece.
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The spacing between the jaws and the configuration
of the elongated plates permit the plates to operate the
workpiece while engaging only four faces of the workpiece
and encircling the workpiece through an arc of only 240
degrees. As a result, the wrench can easily be inserted
onto and removed from the workpiece from the side for
ease of use in cramped spaces. In preferred embodiments,
the ratcheting operation is assisted by a spring which
biases one of the plates toward the opening, which makes
turning the workpiece fast and easy while requiring no
clearance behind the workpiece.
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Preferred embodiments may include one or more of
the following additional features.
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The plates are mounted for the selective movement
in response to rotation of the handle. No separate
locking or unlocking mechanism is needed to change the
operating state of the wrench. For example, after
turning the workpiece in the first direction, the wrench
is simply rotated in the opposite direction to move the
plates to the second position for ratcheting.
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The first plate is mounted to a first one of the
jaws so that the distal end of the plate is substantially
immobile in the first position, and is pivotable with
respect to the second plate in the second position. In
one embodiment, only the first plate pivots, and it moves
away from the opening and the second plate. In another
embodiment, both plates pivot away from the opening and
each other.
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The plates are substantially immobile with respect
to each other in the first position in that they cannot
spread apart from each other. To further avoid slippage
when driving the workpiece, in one embodiment one or both
of the plates are mounted so that when in the first
position the distal ends of the plates are movable toward
each other. This enhances the gripping strength of the
plates against the workpiece, and is particularly useful
for driving an undersized workpiece.
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A distal pin on the distal end of the first plate
is received by a slot disposed in a distal region of the
first jaw. Alternatively, the distal slot is in the
first jaw, and the distal pin is on the plate. In each
case, the distal pin is disposed in a first portion of
the distal slot when the plate is in the first position,
and is disposed in a second portion of the distal slot
when the plate is in the second position.
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The first portion of the distal slot is oriented
so that the engagement of the distal pin therein holds
the distal end of the first plate substantially immobile
with respect to the second plate when the wrench is
rotated in the first direction, and the second portion of
the distal slot is oriented to allow the distal end of
the first plate to pivot with respect to the second plate
when the wrench is rotated in the second direction. In
one embodiment, the distal slot is "V" shaped; that is,
the distal slot has a pair of acutely-angled lobes. The
base of the "V" is oriented either toward or away from
the handle.
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A proximal pin on the proximal end of the first
plate is received by a slot disposed in a proximal region
of the first jaw. The proximal slot and the first
portion of the distal slot are oriented (preferably along
a common arc of curvature) to allow the selective
movement of the first plate between the first and second
positions. The center of the common arc of curvature is
disposed in the opening. The second portion of the
distal slot is arranged transversely to the arc of
curvature.
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The proximal pin is also mounted to the proximal
end of the second plate. A distal pin at a distal end of
the second plate is received by a slot disposed in a
distal region of the second jaw. This distal slot is,
with the proximal slot, oriented to allow the selective
movement of the second plate between the first and second
positions.
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The plates and the spring are arranged so that
turning the wrench over with respect to the workpiece
reverses operation of the wrench in the first and second
directions. That is, with the wrench turned over, the
wrench tightens or loosens the workpiece when rotated in
the second direction, and produces the ratcheting action
when rotated in the first direction.
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As an alternative to the dual-lobe approach, the
distal slot associated with the first plate is oriented
transversely to an arc of curvature centered in the
opening, with a first portion of the distal slot
intersecting the arc and a second portion of the distal
slot being positioned radially inside of the arc. The
distal pin is disposed in the first portion of the distal
slot in the first position, and is movable into the
second portion of the distal slot in the second position
to cause the first plate to pivot with respect to the
second plate.
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One of the advantages of this embodiment of the
wrench is additional manufacturing simplicity. The
transverse distal slot is easier to lay out and cut than,
e.g., the dual-lobe (e.g., V-shaped) slots of the above-discussed
embodiments, and may be more resistant to wear
over the long term.
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The first and second portions of the distal slot
are at opposite (distal and proximal) ends of the distal
slot. The first and second portions of the distal slot
may be curved or straight.
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The distal slot may also include a region oriented
to receive the distal pin and cause the first plate to
move toward the second plate and further grip the
workpiece when the handle is rotated in the first
direction. This region of the distal slot is positioned
radially outside of the arc. In one embodiment, the
first portion and the region are at a distal end of the
distal slot, and the second portion is at a proximal end
of the distal slot; in another embodiment, the first
portion and the region are at a proximal end of the
distal slot, and the second portion is at a distal end of
the distal slot.
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A proximal pin on proximal end of the first plate
is received by a proximal slot disposed in a proximal
region of the first jaw. The proximal pin is disposed in
a first portion of the proximal slot in the first
position, and is movable into a second portion of the
proximal slot in the second position. The first plate
pivots about the proximal pin away from the second plate
in the second position. The first and second portions of
the proximal slot are oriented along the arc.
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A spring is positioned to bias the first plate to
return from the second position toward the first
position.
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The wrench also includes a second distal pin on
one of a distal end of the second plate or a distal
region of the second jaw, and a second distal slot
disposed in the other one of the distal end of the second
plate or the distal region of the second jaw. The
second distal pin is disposed in a first portion of the
second distal slot in the first position, and is movable
into a second portion of the second distal slot in the
second position. The first and second portions of this
distal slot are also at opposite ends of the second
distal slot.
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In one embodiment, the second distal slot is
oriented along the arc so that the second plate does not
pivot with respect to the first plate as the second
distal pin moves from the first portion to the second
portion of the second distal slot. In another approach,
the second distal slot is oriented transversely to the
arc, with the first portion thereof intersecting the arc
and the second portion thereof being positioned radially
inside of the arc, so that the second plate pivots with
respect to the first plate as the second distal pin moves
from the first portion to the second portion of the
second distal slot.
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The first and second portions of the second distal
slot may be curved or straight. The second portions of
the distal slots are located at opposite ends thereof.
Each of the distal slots also comprises a region oriented
to receive the respective distal pin and cause the first
and second plates to move toward each other and further
grip the workpiece when the handle is rotated in the
first direction. These regions are positioned radially
outside of the arc and are located at opposite ends of
the respective distal slots. The first and second plates
pivots about the proximal pin away from each other in the
second position.
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Although the plates can have different
configurations, it may be advantageous in some
embodiments to configure the plates to be identical.
This significantly simplifies manufacture and, along with
the manner in which the plates are movably mounted to the
jaws renders the wrench easily scalable in size. Each
plate preferably has a plurality of the engaging
surfaces, and each surface is elongated so as to engage a
face of the workpiece over a major portion of a length of
the face. The engaging surfaces are flat. The engaging
surfaces are arranged to define an angle therebetween
equal to an angle between adjacent faces of the
workpiece. In one embodiment, the portion of each plate
that includes the workpiece engaging surface has an
enlarged thickness relative to another portion of the
plate.
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Other features and advantages of the invention
will become apparent from the following detailed
description, and from the claims.
Drawings
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Fig. 1 is a top plan view of an open-end ratchet
wrench.
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Fig. 2 is a side view of the wrench of Fig. 1.
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Fig. 3 shows the wrench of Fig. 1 with the front
face plate removed to illustrate a pair of elongated
plates that are pivotally mounted on the wrench.
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Figs. 4 and 5 are plan and side views,
respectively, of one of the plates shown in Fig. 2.
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Fig. 6 illustrates another embodiment of the
wrench being used to turn a workpiece in the driving
direction (D). Figs. 7 and 8 show the operation of the
wrench of Figs. 6 in the non-driving (ratcheting)
direction (R).
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Fig. 9 is a top plan view of another embodiment of
an open-end ratchet wrench.
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Fig. 10 shows the wrench of Fig. 9 with the front
face plate removed to illustrate a pair of elongated
plates that are pivotally mounted on the wrench.
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Figs. 11A, 11B and 12A, 12B are plan and side
views, respectively, of the plates shown in Fig. 10.
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Fig. 13 is a cross-sectional view of the head of
the wrench of Fig. 9 engaged with a workpiece (W) and
placed against a surface (S).
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Figs. 14A and 14B show an alternative
configuration of the elongated plates shown in Fig. 10.
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Figs. 15A-15C and 16A-16B illustrate another
embodiment of the wrench.
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Figs. 17A-17E are useful in understanding an
alternative configuration for one of the movable plates
of the wrench.
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Figs. 18-20C illustrate another embodiment of the
wrench.
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Figs. 21-23C illustrate yet another embodiment of
the wrench.
Detailed Description
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The wrenches of this invention are similar to
those of my U.S. Patent No. 5,456,143 ("the '143 patent")
and my copending U.S. patent application Serial No.
08/728,627 ("the '627 application"), both of which are
entitled "Open End Ratchet Wrench" and are incorporated
herein by reference. The wrenches of the present
invention have many of the advantages of the wrenches of
the '143 patent and the '627 application, plus additional
advantages that have been discussed or that will become
apparent.
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Referring to Figs. 1-3, open-end ratchet wrench 15
includes a pair of arcuate jaws 16, 17 at the end of an
elongated handle 18. Jaw 16 is somewhat larger than jaw
17 and protrudes more markedly from handle 18 than does
jaw 17 for purposes to be described. Jaws 16, 17 and
handle 18 are defined by a pair of face plates 20, 22
(Fig. 2). A central plate 24 is sandwiched between face
plates 20, 22 in handle 18 to provide space in jaws 16,
17 for a pair of elongated plates 26, 28 that are movably
mounted to face plates 20, 22 within jaws 16, 17 in a
manner described below. Plates 20, 22, 24 are secured
together in handle 18 in any suitable way, such as by
screws (not shown). The components of wrench 15 are made
of tool steel or hardened steel for ruggedness.
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One of the advantages of wrench 15 is its simple
construction. Front and back plates 20, 22 are identical
to each other, and elongated plates 26, 28 are also
identically constructed. Thus, wrench 15 is easy to
manufacture, and can easily be scaled up or down in size
(i.e., enlarged or miniaturized with respect to standard-sized
open-end wrenches).
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As best shown in Figs. 1 and 2, face plates 20, 22
extend longitudinally beyond the distal end 25 of central
plate 24 to form a generally "C" shaped head 19 in which
arcuate jaws 16, 17 are disposed. Jaws 16, 17 are
laterally spaced from each other by any suitable amount
to partially encircle a central opening 21 for receiving
a workpiece (e.g., the head of a bolt, a nut, or an in-line
fitting) by no more than 240 degrees. As a result,
sufficient spacing S is provided between the tips and
workpiece-engaging surfaces of plates 26, 28 to allow
wrench 15 to be inserted onto the workpiece from the side
rather than from above (or below) the workpiece.
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Figs. 4 and 5 show elongated plate 26 separately
from the remainder of wrench 15. As discussed, plates
26, 28 are identical, and thus plate 28 is not separately
shown. Elongated plates 26, 28 are curved (more
specifically, reniform, or kidney, shaped) and are
slightly thinner than central plate 24 so that they may
move easily between face plates 20, 22. The inner
concave sides of elongated plates 26, 28 (i.e., the sides
of plates 26, 28 that oppose each other) are notched to
define a series of cusps 30, each of which is defined by
a pair of flat surfaces 30a, 30b. Each plate 26, 28
includes three notches 31 defined by adjacent cusps 30 of
the plate, and plates 26, 28 define another, central
notch 31 at the junction between the plates. Elongated
surfaces 30a, 30b that meet at a notch 31 are oriented at
an angle that matches the angle defined by a pair of
adjacent faces of the workpiece (which, for a hexagonal
bolt head or nut, is 120 degrees).
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Plates 26, 28 provide a total of sixteen surfaces
30a, 30b and eight cusps 30 arranged over an arc of 240
degrees (Fig. 1). As a result, the arrangement of
surfaces 30a, 30n on plates 26, 28 corresponds to a so-called
"12-point" design. (That is, if the plates were
to be extended to define a 360 degree figure, they would
provide twelve cusps 30 or "points," and twenty four
surfaces 30a, 30b. The term "12-point" design is
commonly used for socket wrenches to describe the number
of "points" defined by the socket.)
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The proximal ends of elongated plates 26, 28 are
stepped-down in thickness at a shoulder 29 to define a
shelf 29a at the base of each plate 26, 28. Shelves 29a
are approximately one-half of the thickness of the
remainder of each plate. A pair of round holes 31a, 31b
are formed in each plate 26, 28, one (hole 31a) in the
distal region of the plate, the other (31b) in shelf 29a.
As discussed below, holes 31a, 31b receive pins that also
pass through face plates 20, 22 for movably mounting
elongated plates 26, 28 in wrench head 19.
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Because of their identical shape, when plates 26,
28 are mounted within jaws 16, 17 with their elongated
surfaces 30a, 30b facing each other, one plate (e.g.,
plate 26) will be face-up, and the other (plate 28) will
be face-down. As a result, shelves 29a of the two plates
will overlap with each other, with their holes 31b
aligned in registry.
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When elongated plates 26, 28 are in their rest
position (shown by Figs. 1 and 2), their elongated
surfaces 30a, 30b extend into central opening 21 by an
amount sufficient to engage and grasp the faces of a
hexagonal workpiece when holding a hexagonal workpiece in
the position shown in Fig. 3 or in a position rotated by
30 degrees from that shown in Fig. 3. Each elongated
surface 30a, 30b is configured to engage a face of the
workpiece over a major portion (such as at least 54%) of
the length of the face. Elongated plates 26, 28 are
restrained in their movement and held between face plates
20, 22 by three pins 32, 34, 36 which pass from face
plate 20 to face plate 22 through respective slots 42,
44, 46 in face plates 20, 22 and round holes 31 in
elongated plates 26, 28. Pins 32, 36 are secured within
the distal holes 31a of respective plates 26, 28, while
pin 34 is secured within the aligned proximal holes 31b
of plates 26, 28. As discussed below, pin 34 is held
sufficiently loosely within hole 31b of plate 26 to allow
plate 26 to pivot about pin 34 during ratcheting.
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Slots 42, 44, 46 in face plate 20 are identical to
and are aligned in registry with corresponding slots 42,
44, 46 in face plate 22. Slots 42 are located in a
distal region of jaw 17, slots 44 are positioned in a
proximal base 23 of the jaws in wrench head 19, and slots
46 are located in a distal region of jaw 16. Slots 42,
44 are oriented along a common arc of curvature centered
at the center C of workpiece W (Fig. 3). (Center C is
also the center of wrench head 19.) Slot 46 comprises a
pair of lobes 48, 50. Inner lobe 48 is oriented along
the same arc of curvature as slots 42, 44. Slots 42, 44
and inner lobe 48 of slot 46 each define an arc length of
10-12 degrees.
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Outer lobe 50 of slot 46 is transverse to, and
extends radially outwardly from, lobe 48. In particular,
outer lobe 50 extends along an arc centered at a point 45
(Fig. 1) that corresponds to the center of pin 34 when
the pin is positioned on the opposite side of slot 44
(shown as pin 34' in dashed lines in Fig. 1). As
explained below, pin position 34' corresponds to the
"unlocked" or ratcheting position of elongated plates 26,
28. Outer lobe 50 extends from a distal end at the
distal end of inner lobe 48, to a proximal end that is
radially spaced from that of inner lobe 48, along an arc
length of 9-10 degrees. As a result, the overall
configuration of slot 46 is V-shaped. Jaw 16 is enlarged
with respect to jaw 17 in the manner discussed above to
provide room for V-shaped slot 46 without unduly
weakening jaw 16.
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A leaf spring 50 (Fig. 2) is placed in base 23 of
head 19 at the end of handle 18. One end 52 of leaf
spring 50 is captured within an angled (with respect to
the central longitudinal axis of handle 18) groove 54 in
central plate 24. The opposite end 56 of leaf spring 50
engages the curved outer surface 27 of plate 26, thereby
biasing plate 26 inwardly towards the center C of wrench
head 19 and against workpiece W (Fig. 3).
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When wrench 15 is in the position shown in Fig. 3,
pin 36 engages the proximal ends of inner lobes 48 of
slots 46, pin 34 engages the inner (with respect to
opening 21) surfaces of slots 44 at the right-most ends
(as seen in Fig. 3) of slot 44, and pin 32 is located at
the distal ends of slots 42. Elongated plates 26, 28
thus are in a "locked" position and are immobile relative
to each other when wrench 15 is turned in a driving
direction D (e.g., clockwise, as shown in Fig. 3).
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The operation of the wrench is described in more
detail below with reference to the embodiment of Figs. 6-8.
But briefly, after jaws 16, 17 are slid onto
workpiece W from the side, wrench 15 is rotated in
driving direction D to turn workpiece W. As handle 18 is
turned in the driving direction, pressure develops
between workpiece W and surfaces 30a of plates 26, 28.
This pressure urges plates 26, 28 and pins 32, 36
outwardly and away from center C, and also urges the
proximal ends of plates 26, 28 and pin 34 inwardly toward
center C. These motions are prevented by the engagement
of pins 32, 36 with the distal and proximal surfaces of
slots 42, 46, and the engagement of pin against the inner
and right-most end surfaces of slots 44. Accordingly,
plates 26, 28 remain immobile with respect to each other
in jaws 16, 17, grasp workpiece W between them at
elongated surfaces 30a and rotate workpiece W in driving
direction D.
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When handle 18 is turned in the opposite (e.g.,
counterclockwise) direction from arrow D, ratcheting
occurs. That is, plates 26, 28 slide over the surface of
the workpiece, allowing the workpiece to remain
stationary. This operation is explained in detail below
with respect to Figs. 7 and 8. Briefly, however, when
handle 18 is first rotated in the ratcheting direction,
pins 32, 34 travel to an "unlocked" position at the
opposite ends of respective slots 42, 44 along the common
arc of curvature of the slots. That is, pins 32, 34 move
to the proximal end of slot 42 and the left-most end of
slot 44, respectively. Likewise, pin 36 moves within
inner lobe 48 of slot 46 to the opposite (i.e., distal)
end of lobe 48 (which also corresponds to one end of
outer lobe 50, as discussed above). As a result,
elongated plates 26, 28 rotate around center C with
handle 18 until pins 32, 34, 36 reach the ends of slots
42, 44 and slot lobe 48, respectively. This operation
requires approximately 10-12 degrees of handle rotation,
which corresponds to the arc length of the slots.
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With pins 32, 34, 36 positioned as just described,
plates 26, 28 are "unlocked" and are ready for
ratcheting. As handle 18 is rotated further
counterclockwise (e.g. by 30 degrees for the 12-point
configuration shown in Fig. 3), the engagement of plate
26 against workpiece W causes plate 26 to pivot outwardly
from center C about centerpoint 45 (Fig. 1) of pin 34 as
each corner of the workpiece slides across an elongated
surface 30a or 30b of plate 26. Plate 28 remains
stationary during the pivoting motion of plate 26. The
pivoting motion of plate 26 is constrained by outer lobe
50 of slot 46. That is, pin 36 travels within outer lobe
50 as plate 26 pivots.
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Leaf spring 50 biases plate inwardly toward center
C. Thus, as the corners of the workpiece move toward
notches 31, spring 50 urges plate 26 to pivot inwardly
around centerpoint 45 of pin 34 in position 34', and back
into full engagement with the workpiece surfaces. In the
12-point design shown in Fig. 3, approximately 30 degrees
of handle rotation are needed to ratchet jaws 16, 17
around one corner of a hexagonal workpiece.
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Because of the symmetrical construction of wrench
15, the driving and ratcheting direction can be reversed
simply by turning wrench 15 over with respect to the
workpiece (i.e., so that jaw 15 is on the right when
viewed from above). In this orientation, the driving
direction D is counterclockwise, and the ratcheting
direction R is clockwise.
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Other embodiments are within the scope of the
following claims.
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For example, the wrench may have elongated plates
with more or fewer workpiece grasping surfaces.
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Figs. 6-8 show a wrench 115 with so-called "6-point"
design in which jaws 116, 117 respectively support
elongated plates 126, 128 that each have two workpiece
engaging surfaces 130. Surfaces 130 are each
sufficiently long to engage a face of workpiece W along
the entire length of the face. Surfaces 130 define an
angle of 120° and a notch 131 therebetween. In other
respects, wrench 115 is identical to wrench 15, and thus
the other components of wrench 115 have been given the
same reference numerals as the corresponding components
of wrench 15.
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In operation, after wrench 115 is inserted onto
workpiece W from the side, handle 20 is turned in a
driving direction (D, Fig. 6) (e.g., clockwise) to rotate
workpiece W. As discussed above for wrench 15, plates
126, 128 are in the "locked" position because of the
position of pins 32, 34, 36 in respective slots 42, 44,
46. Thus, as handle 20 is turned in direction D,
pressure develops between workpiece W and surfaces 130 of
plates 126, 128. This pressure urges plates 126, 128 and
pins 32, 36 outwardly and away from center C, and the
proximal ends of plates 126, 128 and pin 34 inwardly
toward center C. This motion is prevented by the
engagement of pins 32, 36 against the distal and proximal
ends, respectively, of slots 42, 46, as well as by the
engagement of pin 34 against the inner and right-hand end
(as viewed in Fig. 6) of slot 34. Accordingly, plates
126, 128 remain immobile with respect to each other in
jaws 116, 117, grasp workpiece W therebetween, and turn
the workpiece in response to the handle rotation.
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Referring to Fig. 7, the ratcheting operation is
performed by turning handle 20 in the opposite direction
R (counterclockwise, in this example). As handle 20 is
first moved in direction R, pressure develops between
workpiece W and surfaces 130 of plates 126, 128. This
force causes pins 32, 34, 36 to slide to the opposite
ends of slots 42, 44 and inner lobe 48 of slot 46,
respectively, thereby causing plates 126, 128 to rotate
within jaws 116, 117 along the common arc of curvature of
these slots. When pins 32, 34, 36 reach the opposite
ends of the respective slots (which occurs after
approximately 10°-12° of handle rotation), elongated
plates 126, 128 are in the "unlocked" position for
ratcheting.
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Referring to Fig. 8, further rotation of handle 20
in direction R around workpiece W causes additional
pressure to be exerted against plates 126, 128 by
workpiece W. This pressure causes plate 126 to pivot
about pin 34 outwardly with respect to the workpiece and
the remainder of jaw 116. This motion is constrained by
pin 36, which travels in outer lobe 50 of slot 46. As a
result, elongated surfaces 130 of plates 126, 128 slide
around the corners of workpiece W, allowing the workpiece
to remain stationary.
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Once jaws 116, 118 have been rotated approximately
60° to a new ratcheting position (i.e., as a corner of
the workpiece W slides into an adjacent notch 131),
biasing spring 50 urges plate 126 to pivot inwardly about
pin 34 so that pin 36 travels to its unlocked position at
the distal end of lobes 48, 50. If further ratcheting is
desired, the user continues to rotate handle 20 in
direction R. Otherwise, the user resumes rotating handle
20 in driving direction D. For the initial few degrees
of rotation in direction D, plates 126, 128 will not turn
the workpiece but will instead rotate to their "locked"
position as pins 32, 34, 36 move to the ends of the slots
as shown in Fig. 6. Thereafter, further rotation of
handle in the driving (e.g., clockwise) direction will
cause plates 126, 128 to grasp and turn the workpiece.
-
Still other embodiments are within the scope of
the claims.
-
For example, the positions of the distal pins and
slots may be reversed. That is, referring to Fig. 3,
pins 32, 36 may be formed in the face plates, and slots
42, 46 defined in the distal regions of plates 26, 28.
-
Figs. 9 and 10 show an open-end ratchet wrench 215
having such a reversed distal pin-slot construction.
Wrench 215 is similar in construction to wrench 15, and
includes a pair of arcuate jaws 216, 217 at the end of an
elongated handle 218. Jaw 216 is somewhat larger than
jaw 217 and protrudes more markedly from handle 218 than
does jaw 217, for the reasons discussed above. Jaws 216,
217 and handle 218 are defined by a pair of face plates
220, 222, and a central plate 224 is sandwiched
therebetween in handle 218 to provide space in jaws 216,
217 for a pair of elongated plates 226, 228. Elongated
plates 226, 228 have the same curved shape as plates 26,
28 of wrench 15, and are movably mounted to face plates
220, 222 with the reversed distal pin-slot construction.
That is, the distal slots are in elongated plates 226,
228 (rather than in the face plates that define jaws 216,
217), and the distal pins are secured to face plates 220,
222 (rather than to the elongated plates).
-
More specifically, elongated plate 228 includes a
curved distal slot 242 that receives a pin 232 secured
within round holes 231 in face plates 220, 222. A V-shaped
distal slot 246 of elongated plate 226 includes a
pair of lobes 248, 250 and receives a pin 236 which is
secured within round holes 231 in face plates 220, 222.
As will be appreciated by comparing Fig. 10 with Fig. 3,
V-shaped slot 246 is arranged oppositely with respect to
V-shaped slot 46 of wrench 15. That is, the base of the
"V" of slot 246 is oriented toward the handle and the
proximal end of elongated plate 226 (rather than away
from the handle and toward the distal end of the plate,
as is slot 46 in Fig. 3). A proximal pin 234 is secured
within holes 233 in the proximal ends of plates 226, 228
(which, as discussed below, are aligned with each other)
and is received by proximal slots 244 in face plates 220,
222 (only one of which is shown in Fig. 9).
-
Slots 242, 244 and lobe 248 of slot 246 are
oriented along the same arc of curvature centered at
workpiece center C and define an arc length of 10-12
degrees. Lobe 250 of slot 246 is transverse to and
extends radially inwardly from lobe 248 along an arc
centered at the center of hole 233 in plate 226 (see Fig.
11A) that corresponds to the center of pin 234. Lobe 250
curves radially inwardly toward the workpiece from a
proximal end at the proximal end of lobe 248 to a distal
end that is radially spaced from that of inner lobe 248,
along an arc length of 9-10 degrees.
-
A leaf spring 250 (Fig. 10) is placed in base 223
of the wrench head at the end of handle 218. One end 252
of leaf spring 250 is captured within a groove 254 in
central plate 224 (groove 254 is shown angled with
respect to the central longitudinal axis of handle 218,
but it may be straight instead). The opposite end 256 of
leaf spring 250 engages the curved outer surface of
elongated plate 226, thereby biasing plate 226 inwardly
towards the center C of the wrench head and against
workpiece W.
-
Elongated plates 226, 228 are shown apart from the
remainder of wrench 215 in Figs. 11A and 11B (top views),
Figs. 12A and 12B (side views), and Fig. 13 (a cross-sectional
view). Except for their different distal slot
configuration, plates 226, 228 are constructed
identically to each other. As with the elongated plates
of wrench 15, plates 226, 228 are kidney-shaped and
provide a total of sixteen workpiece engaging surfaces
230a, 230b and eight cusps 230 arranged over an arc of
240 degrees. As a result, the arrangement of surfaces
230a, 230b on plates 226, 228 corresponds to a so-called
"12-point" design. (That is, if the plates were to be
extended to define a 360 degree figure, they would
provide twelve cusps 230 or "points," and twenty four
workpiece engaging surfaces 230a, 230b.) Surfaces 230a,
230b alternate with each other along plates 226, 228, as
shown in Fig.s 11A and 11B.
-
The proximal end of each elongated plate 226, 228
is stepped-down in thickness at a shoulder 229 to define
a shelf 229a at the base of the plate. Shelves 229a are
approximately one-half of the nominal thickness T of each
plate 226, 226. The regions of plates 226, 228 which
include workpiece engaging surfaces 230a, 230b are
thickened with integral flanges 237, 239, respectively,
as best seen in Fig. 13 (the spacing between the
elongated plates and face plates 220, 222 is shown
exaggerated for ease of viewing). Flanges 237, 239
increase the contact area of surfaces 230a, 230b with the
workpiece for increased strength.
-
Because of their identical shape, when plates 226,
228 are mounted within jaws 216, 217 with their elongated
surfaces 230a, 230b facing each other, one plate (e.g.,
plate 226) will be face-up, and the other (plate 228)
will be face-down. As a result, shelves 229a of the two
plates will overlap with each other, with their holes 233
aligned in registry to receive pin 234.
-
The user operates wrench 215 in the same manner as
described above for wrench 15. To briefly reiterate,
after jaws 216, 217 are slid onto workpiece W from the
side, wrench 215 is rotated in a driving direction (e.g.,
clockwise in Figs. 9 and 10) to turn workpiece W. Figs.
9 and 10 show wrench 215 in the "locked" position, in
which pin 232 is located at the proximal end of slot 242,
pin 234 is positioned at the right-most end of slot 244,
and pin 236 is disposed at the distal end of slot lobe
248. As the user turns handle 218 in the driving
direction, pressure develops between workpiece W and
surfaces 230a of plates 226, 228. This pressure urges
plates 226, 228 (and hence slot lobe 248 and slot 242,
respectively) outwardly and away from center C, and also
urges the proximal ends of plates 226, 228 and pin 234
inwardly toward center C. These motions are prevented by
the engagement of the surfaces of slot 242 with pin 232,
the engagement of the surfaces of slot lobe 248 against
pin 236, and the engagement of pin 234 against the inner
and right-most end surfaces of slots 244. Accordingly,
plates 226, 228 remain immobile with respect to each
other in jaws 216, 217, grasp workpiece W between them at
elongated surfaces 230a, and rotate workpiece W in the
driving direction.
-
When handle 218 is turned in the opposite (e.g.,
counterclockwise) direction, ratcheting occurs, in which
plates 226, 228 slide over the surface of the workpiece,
allowing the workpiece to remain stationary. Ratcheting
is performed as follows. When handle 218 is first
rotated in the ratcheting direction, pressure applied by
the workpiece to engaging surfaces 230b causes plates
226, 228 to remain stationary while handle 218 rotates.
As a result, slot 244 slides over pin 234 until pin 234
reaches position 234' at the left end of slot 244 (as
shown in Fig. 9). At the same time, pins 232, 236 (which
are held within jaw arms 216, 217) slide through slot 242
and slot lobe 248, respectively, along the common arc of
curvature of the slots until pin 232 reaches the distal
(i.e., upper) end of slot 242 and pin 236 reaches the
proximal (i.e., lower) end of slot lobe 248. Movement of
wrench 215 to this "unlocked" position (which can be
thought of either as rotating plates 226, 228 clockwise
relative to handle 218, or turning handle 218
counterclockwise relative to plates 226, 228) requires
approximately 10-12 degrees of handle rotation, which
corresponds to the arc length of the slots.
-
As handle 218 is rotated further counterclockwise
(e.g. by 30 degrees for the 12-point configuration shown
in Figs. 9 and 10), workpiece W exerts pressure against
engagement surfaces 230b, which in turn applies an
outwardly directed pressure against plate 226. This
outward pressure causes plate 226 (and thus slot 246) to
pivot outwardly from center C about centerpoint 245 (Fig.
9) of pin 234 in position 234' as each corner of the
workpiece slides across an elongated surface 230a or 230b
of plate 226. Plate 228 remains stationary during the
pivoting motion of plate 226. The pivoting motion of
plate 226 is constrained by lobe 250 of slot 246. That
is, slot lobe 250 slides over pin 236 as plate 226
pivots.
-
Leaf spring 250 biases plate 226 inwardly toward
center C. Thus, as the corners of the workpiece move
toward notches 231, spring 250 urges plate 226 to pivot
inwardly around centerpoint 245 of pin 234 in position
234', and back into full engagement with the workpiece
surfaces. In the 12-point design shown in Fig. 9,
approximately 30 degrees of handle rotation are needed to
ratchet jaws 216, 217 around one corner of a hexagonal
workpiece.
-
Because of the symmetrical construction of wrench
215, the driving and ratcheting direction can be reversed
simply by turning wrench 215 over with respect to the
workpiece (i.e., so that jaw 216 is on the right when
viewed from above). In this orientation, the driving
direction is counterclockwise, and the ratcheting
direction is clockwise.
-
Among other advantages, placing distal slots 242,
246 in elongated plates 226, 228 allows V-shaped slot 246
(and hence pin 236) to be positioned radially further
away from centerpoint C (i.e., toward the outer periphery
of plate 226). In part, this is because lobe 250 of slot
248 curves inwardly toward the workpiece, rather than
outwardly away from the workpiece (as with lobe 50 of
wrench 15). As a result, less torque is applied to all
of the pins 232-236 as they move peripherally, thereby
reducing the risk of shearing the pins and adding to the
overall strength of wrench 215.
-
It should also be noted that lobe 250 is smaller
than lobe 50 of wrench 15 (Fig. 3), for the following
reason. Although the curvature of each lobe 50, 250 is
centered about the respective proximal pin, lobe 250 is
located radially closer to proximal pin 234 than lobe 50
is to proximal pin 34. This allows lobe 250 to define a
shorter length than lobe 50, even though the arc angles
of two lobes are the same. Because of the relatively
shorter length of lobe 250, it does not cut into lobe 248
as much as lobe 50 cuts into lobe 48. As a result, pin
236 is more fully seated within V-shaped slot 246, which
reduces the chance of plate 226 being forced from lobe
248 to lobe 250 during driving. Moreover, because pins
232, 236 are secured at both ends to plates 220, 222, the
pins are less likely to bend or diverge when wrench 215
applies large driving forces to the workpiece.
-
In addition to increasing the surface contact with
the workpiece and increasing the strength of plates 226,
228, flanges 237, 239 reduce wear on both surfaces 230a,
230b and the workpiece surfaces. Moreover, as shown in
Fig. 13, the workpiece is fully captured between plates
226, 228 to a completely seated position when wrench 215
is flush against a surface S that abuts workpiece W.
This reduces the risk of wrench 215 slipping off of the
workpiece.
-
Wrench 215 may have more or fewer workpiece
engaging surfaces. For example, referring to Figs. 14A
and 14B, elongated plates 226', 228' each have only two
workpiece engaging surfaces 260. As discussed above,
with this configuration, wrench 215 would have a so-called
"6-point" design (as discussed above for Figs. 6-8).
Each surface 260 includes driving portions 230a' and
adjacent ratcheting portions 230b'. That is, during the
driving operation, portions 230a' exert pressure against
the workpiece to rotate the workpiece as handle 218 is
turned. During ratcheting, the workpiece exerts pressure
against portions 230b' to cause plate 226 to pivot.
-
Referring to Figs. 15A-15C and 16A-16B, the
movable plates need not be identical or symmetrical with
respect to the central longitudinal axis of the wrench.
Wrench 315 has a pair of differently configured movable
plates 326, 328 positioned in jaws 316, 317 at the distal
end of handle 320. Plate 326 (shown apart from the wrench
in Fig. 16A) is smaller than plate 328 (Fig. 16B).
Either of the distal pin-slot arrangements discussed
herein can be used in this embodiment. In the embodiment
of wrench 315 shown in the figures, distal slots 342, 246
are in plates 326, 328, and distal pins 332, 336 are
mounted in the face plates of the wrench.
-
Plates 326, 328 include proximal holes 333, which
are aligned and receive proximal pin 334, which in turn
passes through a proximal slot 344 in the face plates of
the wrench. Wrench 315 operates in the same way as
discussed above for wrench 314. Fig. 15A shows wrench
315 in the locked position, in which distal pin 336 is
captured within lobe 348 of slot 346. Figs. 15B and 15C
illustrate wrench 315 during ratcheting, in which distal
pin 336 moves back and forth within lobe 350 of slot 346.
(Figs. 15B and 15C are drawn as if the front face plate
of the wrench has been removed, but the spring which
engages plate 326, as in the other embodiments, is not
shown.)
-
Among other advantages, proximal pin 334 is
positioned relatively closely to slot lobe 350 compared
with the other embodiments. This allows the length of
lobe 350 to be reduced, and the angle between lobes 348,
350 to be increased. As a result, more material is
present at the junction 360 (Fig. 16A) between the lobes,
which provides greater holding power to maintain pin in
lobe 348 (i.e., in the locked position) when the user
applies large driving forces to the workpiece.
-
Referring to Figs. 17A-17E, the V-shaped distal
slot of any of the embodiments of my wrench can be made
smaller than has been illustrated in other figures.
Consider, for example, plate 226 of wrench 215, which is
shown in Fig. 17A. Fig. 17B shows how distal pin 236
moves in slot lobes 248, 250 when wrench 215 is moved
between the "locked" and "unlocked" positions. It will
be appreciated that pin 236 does not travel all the way
to the base of the "V" shape. As illustrated in Fig.
17C, 246 could be reduced in size while still
accommodating the motion of pin 236. The new
configuration of slot 246', with lobes 248' and 250', is
shown in Fig. 17D (and in plate 226 in Fig. 17E).
Because of the small size of slot 246, during ratcheting
plate 226 opens (i.e., pivots outwardly away from the
workpiece) while the wrench is being rotated to the
unlocked position, rather than remaining stationary until
the plate is fully unlocked, as in the embodiments
described above.
-
Among other advantages, reducing the size of the
V-shaped slot minimizes the amount of material that is
removed from the plate, which increases the strength of
the wrench. In addition, the smaller slot more
positively directs the distal pin around the junction
260' (Fig. 17E) between the lobes when the wrench is
moved between the locked and unlocked positions. As a
result, the pin is returned to the locked position even
more positively than in the other embodiments.
-
Referring to Figs. 18A and 18B, the slot for the
pivotable plate need not be dual lobed, as in previously
described embodiments. Wrench 415 has a pair of
differently configured elongated movable plates 426, 428
positioned in jaws 416, 417 at the distal end of handle
418. Plates 426, 428 include respective distal slots
446, 442, which receive distal pins 436, 432,
respectively, mounted in the face plates 420, 422 of the
wrench. Plates 426, 428 include proximal holes 433,
which are aligned and receive proximal pin 434, which in
turn passes through a proximal slot 444 in the face
plates of the wrench. (Alternatively, as in previously-described
embodiments, the positions of distal slots 442,
446 and pins 432, 436 can be reversed -- that is, distal
slots 442, 446 can be formed in the wrench face plates,
and pins 423, 436 can be affixed to plates 426, 428.)
-
Referring also to Fig. 19, the geometry of distal
slots 442, 446 is shown in detail. Distal slot 442 of
plate 428 includes a distal segment 442a that extends
between points 470, 472, and a contiguous proximal
segment 442b that extends between points 470, 474. Point
470 represents the position of the center of pin 432 at
the junction between segments 442a, 442b, and points 472,
474 represent the positions of the center of pin 432 at
opposite ends of segments 442a, 442b.
-
Distal segment 442a extends and is centered along
an arc of curvature 476. Arc 476 is centered in the
opening between the jaws at point C (the center of
workpiece W), and measures 27 degrees between points 470,
472. Proximal segment 442b curves outwardly with respect
to distal segment 442a and forms an approximately 3
degree extension of arc 476 proximally of point 470, so
that the total arc length of slot 442 is 30 degrees. As
a result of the outward curvature, point 474 is offset
radially outwardly from the path defined by arc 476
(which is centered at the center of pin 434) by
approximately 1-2 degrees (along an arc centered at the
center of pin 434). Thus, when pin 432 moves between
points 470, 474 in segment 442b, plate 428 simultaneously
moves 3 degrees along arc 476 and 1-2 degrees inwardly
toward the workpiece.
-
Distal slot 446 of plate 426 includes a proximal
segment 446a that extends between points 480, 482, and a
contiguous distal segment 446b that extends between
points 482, 484. Point 482 represents the position of
the center of pin 436 at the junction of segments 446a,
446b, and points 480, 484 represent the position of the
center of pin 436 at the opposite ends of segments 446a,
446b. Slot 446 extends generally along an arc of
curvature 486 that is concentric with arc 476 -- that is,
arcs 476, 486 define different segments of a circle
centered at point C. The arc length of slot 446 is also
30 degrees (27 degrees for segment 446a, 3 degrees for
segment 446b). For purposes to be described, however,
proximal segment 446a of slot 446 is transverse to arc
486 rather than being centered along arc 486.
Specifically, proximal segment 446a spirals inwardly by
approximately 7-8 degrees as segment 446a extends
proximally from point 482 to point 480. As a result,
point 480 is offset by an arc of approximately 7-8
degrees (centered at the center of pin 434) radially
inwardly from the path defined by arc 486.
-
Distal segment 446b curves outwardly with respect
to proximal segment 446a and forms an approximately 3
degree extension of arc 486 distally of point 470, so
that the total arc length of slot 446 is 30 degrees. As
a result of the outward curvature, point 484 is offset
radially outwardly from the path defined by arc 486 by
approximately 1-2 degrees (arc 486 is also centered at
the center of pin 434). Accordingly, when pin 436 moves
between points 482, 484 in segment 446b, plate 426
simultaneously moves 3 degrees along arc 486 and 1-2
degrees inwardly toward the workpiece.
-
Proximal slot 444 includes curved segments 444a,
444b (Fig. 18) centered along another segment of the same
arc of curvature as arcs 476, 486. (That is, slot 444
and arcs 476, 486 are different segments of a circle
centered at point C.) Unlike distal slots 442, 446, both
segments of proximal slot 444 follow the same arc.
Segment 444a defines an arc length of 27 degrees, and
segment 444b forms a 3 degree extension of segment 444a
for purposes to be described. Proximal slot 444 is
positioned so that with elongated plates 426, 428 in
their at-rest position (shown in Fig. 18A and discussed
below), pin 434 is located at the junction of segments
444a, 444b.
-
Elongated plates 426, 428 are kidney-shaped, and
each has distal and proximal workpiece engaging surfaces
430a, 430b that meet at a notch 431. As a result, the
arrangement of surfaces 430a, 430b on plates 426, 428
corresponds to the "6-point" design discussed above. The
overlapping, proximal ends of elongated plates 426, 428
are each stepped-down in thickness at a shoulder 429 to
define a shelf 429a at the base of the plate. Shelves
429a are approximately one-half of the nominal thickness
of each plate 426, 428. The proximal end 429a of plate
426 includes a hole 464 that receives one end of a coil
spring 450. The opposite end of spring 450 is attached
to a post 462 mounted in wrench handle 418 distal of
center plate 424.
-
Referring to Figs. 20A-20C, spring 450 biases
plates 426, 428 to their at-rest position, in which
distal workpiece engaging surfaces 430a of plates 426,
428 are parallel to each other and are separated by a
spacing S approximately equal to the width of the
workpiece (Figs. 18, 20A). During use, the user engages
wrench 415 with the workpiece (not shown) by sliding jaws
416, 417 onto the workpiece from the side. With plates
426, 428 in the positions shown (i.e., plate 426 on the
left and plate 428 on the right), the user turns handle
418 in the clockwise direction (Fig. 20B) to drive or
rotate the workpiece, and turns handle 418 in the
counterclockwise direction (Fig. 20C) to perform the
ratcheting operation.
-
Note that when plates 426, 428 are in their at-rest
position, spring 450 positions pins 432, 434, 436 at
the junctions between the pair of segments of respective
slots 442, 444, 446 (the position of pin 444 is shown in
Fig. 18A). In particular, pin 432 is located at point
470 (Fig. 19), and pin 436 is disposed at point 482.
-
As the user rotates the handle 3 degrees in the
driving direction, the force applied against the
workpiece compresses spring 450 and moves pins 432, 434,
436 to their fully seated positions at the opposite ends
of slot segments 442b, 444b, 446b. Because segments
442b, 446b are positioned radially outwardly of
respective arcs 476, 486, the movement of pins 432, 436
into segments 442b, 446b (to points 474, 484,
respectively) causes elongated plates 426, 428 to pivot
towards each other about pin 434 to grip the workpiece.
In other words, the spacing S' between distal workpiece
engaging surfaces 430a decreases from at-rest spacing S.
Among other advantages, this gripping feature allows
wrench 415 to firmly grasp and rotate a slightly
undersized workpiece. In addition, the gripping action
helps compensate for possible spreading apart by jaws
416, 417 as wrench 415 tightens the workpiece, which
might otherwise allow plates 426, 428 to open slightly
and slip over the workpiece.
-
The motion of plates 426, 428 during ratcheting is
seen by comparing Figs. 20A and 20C. As the user rotates
the handle counterclockwise from the at-rest position
(Fig. 20A), the force applied against workpiece W causes
pins 432, 434, 436 to travel in slots 442, 444, 446,
against the biasing of spring 450, toward the opposite
ends of slot segments 442a, 444a (Fig. 18), 446a.
Because slot segment 442a is centered along arc 476 (Fig.
19), plate 428 moves in a circular path with respect to
workpiece center C. In contrast, because slot segment
446a spirals inwardly with respect to arc 486 (Fig. 19),
plate 426 pivots about pin 434 and spirals outwardly away
from plate 428 and workpiece center C. In other words,
plate 426 spreads apart from plate 428 by 7 degrees (the
offset of point 480 from arc 486, Fig. 19), thereby
allowing the workpiece engaging surfaces of plates 426,
428 to slide across the corners of the workpiece.
-
Fig. 20C shows plates 426, 428 in their fully open
position during ratcheting. At this point, the user has
rotated the wrench handle in the ratcheting direction by
approximately 27 degrees (i.e., the arc length of slot
segments 442a, 444a, 446a) away from the at-rest position
(or 30 degrees from the gripping position shown in Fig.
20B). When the workpiece engaging surfaces have slid
sufficiently around the corners of the workpiece, spring
450 returns plates 426, 428 to their at-rest position
(Fig. 20A). The user may then either continue the
ratcheting operation, or may instead drive the workpiece
by rotating the handle clockwise.
-
One of the advantages of this embodiment of the
wrench is additional manufacturing simplicity. Spiral
slot 446 is easier to lay out and cut than, e.g., the V-shaped
slots of the above-discussed embodiments, and may
be more resistant to wear over the long term.
-
If the gripping feature is not desired, slot
segments 442b, 444b, and 446b can be eliminated. (Or,
alternatively, slot segments 442b and 446b can be
positioned so that points 474, 484 lie on arcs 476, 486,
respectively.
-
Features of wrench 415 may be applied to the other
embodiments discussed herein. For example, extensions
similar to slot segments 442b, 444b, 446b may be formed
in the slots of the other embodiments of the wrench to
provide the gripping feature.
-
Distal slot 446 may have other configurations in
which point 480 is located radially inside of arc 486 (so
that plate 426 pivots outwardly during ratcheting) and
point 484 is positioned radially outside of arc 486 (to
provide the gripping feature). For example, slot 446 can
define a straight line between points 480 and 484.
-
Although only distal slot 446 has been described
as being transverse to the arc of curvature 486 along
which it generally extends, slot 442 may also (or
instead) be oriented transversely to arc of curvature
476. For example, segment 442a may curve inwardly with
respect to arc 476 so that point 472 (Fig. 19) is
positioned radially inside of arc 476. Orienting both
slots 442, 446 transversely to the arcs would allow both
plates 426, 426 to pivot outwardly away from each other
about pin 434 during ratcheting. As a result, the amount
by which each plate pivots and the amount of handle
rotation needed to move the plates to the fully open
position during ratcheting can be reduced by half,
thereby reducing the stresses applied to spring 450.
-
Fig. 21 shows a wrench 510 in which the distal
slots 542, 546 of both plates 528, 526 are oriented
transversely to the arcs of curvature 576, 586 along
which the slots generally extend. Arcs 576, 587 are
centered at the center C of the opening between jaws 516,
517. The proximal slot 544 (Fig. 23A) extends along the
same arc of curvature as arcs 576, 586, and includes two
concentric segments 544a, 544b.
-
The distal segment 542a of slot 542 is offset
radially inwardly from arc 576 so that when pin 532 is
positioned at the distal end of the slot (point 572),
plate 528 is pivotable away from the workpiece about
proximal pin 534. The proximal segment 542b of slot 542
is offset radially outside of arc 576 to provide the
gripping feature discussed above when pin 532 is
positioned at the proximal end of the slot (point 574).
Pin 532 is shown located at the junction of segments
542a, 542b (point 570), which intersects arc 576.
-
Slot 546 is linear between its proximal and distal
ends (defined by points 580, 584, respectively). The
proximal segment 546a of slot 546 is positioned radially
inwardly of arc 586 so that when pin 536 is positioned at
the proximal end of the slot (point 580), plate 526 is
pivotable away from the workpiece about proximal pin 534.
The distal segment 546b of slot 546 is offset radially
outside of arc 586 to provide the gripping feature
discussed above when pin 536 is positioned at the distal
end of the slot (point 584). Pin 536 is shown located at
the junction of segments 546a, 546b (point 582), which
intersects arc 586. The proximal end of plate 526 is
connected to a spring similar to that shown in Fig. 18B.
-
The operation of wrench 510 is illustrated by
Figs. 22A-22C and 23A-23C (which are identical except
that the latter set of figures show the uppermost plate
of wrench 510 and slot 544).
-
In the starting position (Figs. 22A, 23A), the
spring (not shown) biases plates 526, 528 into their at
rest position, with workpiece engaging surfaces 530a
thereof oriented parallel to each other, and pins 532,
534, 536 are located at the junctions of the two segments
of respective slots 542, 544, 546. As shown in Figs.
22B, 23B, when the user rotates the wrench handle in the
clockwise direction (e.g., by 3 degrees as discussed
above for wrench 415), pins 542, 544, 546 are moved into
slot segments 542b, 544b, 546b, thereby providing the
gripping action against the workpiece (not shown)
discussed above.
-
When the user rotates the handle in the opposite
direction, as shown in Figs. 22C, 23C, the forces applied
against the workpiece engaging surfaces by the workpiece
cause pins 532, 534, 536 to travel to the opposite ends
of respective slots 542, 544, 546. In particular, pins
532, 536 are moved to the distal and proximal ends,
respectively, of slot segments 542a, 546a. Because the
distal end of slot segment 542a and the proximal end of
slot segment 546a are positioned radially inwardly of
arcs 576, 586, the movement of pins 532, 536 therein
causes each plate 526, 528 to pivot outwardly away from
center C. After the wrench handle has been rotated
sufficiently (e.g., by 45 degrees) to slide the workpiece
engaging surfaces sufficiently around the corners of the
workpiece, the spring returns plates 526, 528 to their
at-rest position (Figs. 22A, 23A).
-
In other embodiments, the elongated surfaces of
the movable plates may be curved (e.g., convex with
respect to opening 21) rather than flat. Other numbers
and angular arrangements of elongates surfaces may be
used.
-
The wrench handle need not be in-line with, or in
the same plane as, the jaws, as is shown in the figures.
Instead, as is typical with open-end wrenches, the handle
may be offset at an acute angle to the jaws, either in
the plane of the jaws, or out of the plane of the jaws,
or both. The groove for the biasing spring may be
parallel to the handle axis; indeed, the spring may be
fixed to the handle in other ways.
