Note: Descriptions are shown in the official language in which they were submitted.
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RATCHET FOR REMOVING DAMAGED FASTENERS
FIELD OF INVENTION
The present invention relates to the removal of threaded fasteners. In
particular, the invention relates to the removal of fasteners having flat
faces for
applying torque, where the surfaces have been rounded off or otherwise
damaged through corrosion or wear.
BACKGROUND OF THE INVENTION
Threaded fasteners that have an arrangement of faces for applying torque
to the fastener may become worn or damaged through use. When this occurs,
the tools designed to rotate a threaded fastener can no longer securely grip
the
fastener to apply the torque. A conventional tool slips over the rounded or
damaged corners and does not succeed in rotating the fastener.
A selection of extraction tools designed to remove such damaged
fasteners exist in the prior art. These tools generally use a plurality of
teeth to
engage the fastener. Such "teeth" may be in the form of a plurality of splines
(CA
2391276) or grooves (e.g. US 6598498) that bite into the faces of the fastener
so
as to grip it securely. When the teeth are made up of a selection of faces,
constant use of the tool may result in the buildup of fastener bits between
them,
as well as the dulling of the "biting" edge. Curved arcuate grooves are known
in
the prior art (e.g. US 6598498) but as edges of a fairly small area continue
to
perform the work, are still susceptible to dulling with time.
Many such tools are in the form of an attachment meant to be attached to
a socket wrench (e.g. US 6598498, US 5551320, CA 2232458, CA 2391276, or
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CA 2261087). Such prior art is difficult to use in tight or narrow locations,
and
separate attachments require a separate extraction tool, increase the
complexity
of the fastener removing process, and, due to their size, are easily lost or
misplaced.
Threaded fasteners come in a variety of shapes and sizes. A large set of
wrenches may be required for the removal of different kinds of fasteners,
which is
inconvenient and expensive.
SUMMARY OF THE INVENTION
It is the object of the present invention to overcome the above
disadvantages by having the capacity to remove four different sizes and shapes
of fasteners while retaining the ability to fit into smaller areas.
Additionally, the
helical ridges may be angled in a counter-clockwise direction to assist in the
fastener removal process which may extend the life of the tool.
The invention is directed to a ratcheted wrench for removing threaded
fasteners having a first end and a second end and a handle extending between
the first and second ends, comprising:
a first double-sided fastener extraction head at the first end with
differently sized receiving areas to accommodate differently sized fastener
heads;
a second double-sided fastener extraction head at the second end
with differently sized receiving areas to accommodate differently sized
fastener heads;
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a pair of reversible ratchets, one at each of the first and second
ends, independently permitting each of the first and second extraction
heads to selectively engage the wrench handle or rotate freely relative to
the wrench handle when rotated in a first direction about an axis of
rotation of either the first or the second extraction head.
The invention is further directed to the wrench described above, wherein
each of the receiving areas comprises a plurality of helical ridges that twist
relative to the axis of rotation, and optionally, intersecting faces of each
of the
helical ridges meet at an angle greater than 90 .
The invention is further directed to the wrench described above, wherein
all helical ridges in each of the receiving areas twist relative to the axis
of rotation
of the most proximate extraction head in a first direction.
The invention is further directed to the wrench described above, wherein
each of the differently sized receiving areas are differently sized from all
of the
others, such that the wrench can accommodate four differently sized fastener
heads.
In an alternative embodiment of the wrench described above, the helical
ridges in the receiving areas of the first extraction head twist relative to
the axis
of rotation of the first extraction head in a first direction, and the helical
ridges in
the receiving areas of the second extraction head twist relative to the axis
of
rotation of the second extraction head in a second direction. Further, in this
alternative embodiment, a first receiving area on the first extraction head
and a
first receiving area on the second extraction head are both sized to
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accommodate a first fastener head, and a second receiving area on the first
extraction head and a second receiving area on the second extraction head are
both sized to accommodate a second fastener head, such that the wrench can
accommodate two differently sized fastener heads that can be rotated in both
the
first and second direction.
BRIEF DESCRIPTION OF THE FIGURES
Fig. 1 illustrates a top view of the invention, displaying the wrench shape,
the workings of the reversible ratchet mechanism and the fastener extraction
mechanism.
Fig. 2a illustrates a side view of the invention, displaying the four
differently sized fastener extraction mechanisms as well as the reversible
ratchet
mechanism. Fig. 2b illustrates a side view of the invention, displaying the
two
differently sized fastener extraction mechanisms, each of which rotates in
both
directions, as well as the reversible ratchet mechanism.
Fig. 3 is an exploded perspective view of the embodiment of a head of the
wrench, focusing on the reversible ratchet mechanism.
Fig. 4 is a detailed close up of the top of the head of the wrench, with Figs.
4a and 4b illustrating the way in which the pawl's position and thus the
direction
of the ratchet may be switched.
Fig. 5 is a detailed close up of the pawl used with the ratchet.
Fig. 6 is a section view of the extraction head of the invention,
demonstrating the angled circular arcs used to remove the damaged fastener.
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Fig. 7 is a perspective view of the fastener extraction head, demonstrating
the angled circular arcs used to remove the damaged fastener.
Fig. 8 is a perspective view of the extraction head and the extraction head
cover.
DETAILED DESCRIPTION OF INVENTION
The present invention consists of a wrench with a ratchet mechanism for
the purpose of removing threaded fasteners that have been damaged. The
wrench is double sided and reversible, and has four differently sized and
shaped
apertures so as to accommodate four different sizes and shapes of damaged
fasteners. Each end of the wrench has a toothed gear wheel inside, the centre
of
which is cut so as to serve as a fastener extraction head having two receiving
areas. In one embodiment, each receiving area is defined by six circular
arcuate
cuts or bores which are angled counter-clockwise as the cuts progress into the
aperture. The intersections of the arcuate cuts form sharp ridges which dig
into a
damaged fastener so as to engage it, to apply torque to the fastener to remove
it
or rotate it.
An embodiment of the present invention is shown in Figures 1 and 2a.
The fastener extracting wrench has a handle with double sided fastener
extracting heads 17 and 28 on each end. The wrench is preferably made out of
carbon or stainless steel, but any other material of comparable hardness and
strength may be used as well.
Handle 1 is found in the centre of the wrench. The ends of the wrench
may have two apertures 13 and 14 passing through the ends of each fastener
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extraction head (17 and 28). The fastener extracting heads 17 and 28 defining
these two apertures contain four different sizes and shapes of receiving areas
.
Figure 2a clearly depicts the four different sizes and shapes of receiving
areas 6,
15, 10, and 16. The wrench can thus extract four different sizes of damaged
fasteners.
Another embodiment of the present invention is shown in Figure 2b. The
wrench in this embodiment can both tighten and loosen fasteners of two
different
sizes. The ends of the wrench have two double sided fastener extracting
mechanisms 17 and 28 having two apertures 13 and 14 which contain two
different sizes of receiving areas: 33 and 34 at one size, twisted in opposite
directions, and 35 and 36 at a second size, twisted in opposite directions.
The
wrench can thus extract or tighten two different sizes of damaged fasteners.
The reversible nature of the wrench allows the tool to be used to tighten
damaged fasteners or to remove fasteners with threads that are spun in the
opposite direction.
Figures 3, 4, 4a and 4b demonstrate the workings of the ratchet
mechanism. Aperture 13 includes two compartments 18 and 19 as well as cavity
20. Compartment 18 is indented from the top to create ledge 21. The fastener
extraction head having a gearwheel 11 mounted in compartment 18 in such a
way that the fastener extraction head is free to rotate. A ring of teeth 22
encircles the gear wheel 11's periphery.
To secure gear wheel 11 and pawl 2 within compartments 18 and 19, one
piece ring faceplate 27 may be provided. The first opening 28 is configured to
the
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size and shape of compartment 18, and the rounded tail 29 aligns with
compartment 19. Figure 8 demonstrates how faceplate 27 is secured. Faceplate
27 is pushed into compartments 18 and 19. Within a recess in the head of the
wrench, is placed an engagement means 32, which is biased such that when
cover 27 is positioned into the compartment 18, the engagement means expand
to partially fit within a corresponding recess 37 in faceplate 27.
Pawl 2 is mounted in compartment 19. Figure 5 shows the shape of pawl
2 in detail. Pawl 2 has two sets of two triangle teeth 23 and 24, which engage
with gear wheel 11's ring of teeth 22 as shown in Figures 4, 4a and 4b. Pawl 2
also has two arcuate indentations 25 and 26 which allow for reversing the
ratchet's direction, with the aid of ball 4 and spring 5. Ball 4 is preferably
made of
steel but can be made of other metals as well. Ball 4 fits into arcuate
indentations 25 and 26 so as to direct the placement of pawl 2 (as shown in
Figures 4a and 4b) and so the direction in which gear wheel 11 rotates. Switch
3, with the addition of peg 30, is used to control ball 4 and spring 5.
In operation of the invention, any one of the receiving areas 6, 10, 15, or
16, as shown in Figure 2a, may be positioned over the fastener to be
extracted.
The ratcheting mechanism works as follows. When a fastener is to be extracted
by the tool, gear wheel 11 must be locked in position by pawl 2 when handle 1
is
being turned in the direction that loosens the engaged fastener. When handle 1
is turned in the opposite direction, gear wheel 11 spins through and torque is
no
longer applied to the fastener. Considering fastener conventions, the fastener
would generally be extracted when the receiving area in question is turning in
a
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counter-clockwise direction. Pawl 2 should be positioned so as to ensure that
this
occurs - the receiving area must be locked when handle 1 is rotated in a
counter-clockwise direction, thus removing the fastener.
Figures 4a and 4b demonstrate the two different positions of pawl 2. In
Figure 4a, receiving area 16 is placed over the fastener and handle I is
rotated
counter-clockwise. While such rotation is occurring, gear wheel 11 is locked
and
does not spin, due to the position of pawl 2: pawl 2's teeth are locked with
the
teeth of gear wheel 10. Torque is therefore applied to the fastener, and
removal
occurs. When the handle is then rotated in a clockwise direction, gear wheel
11
spins through, torque is not applied to the fastener, and handle 1 is brought
back
down to starting position.
If a fastener of a different size or shape (matching receiving area 6 in
Figure 2a, for example) then needs to be removed, the wrench is then simply
flipped over and switch 3 pivoted by the user, thus causing peg 30 to cause
ball 4
and spring 5 switch the position of pawl 2. Receiving area 6 may now be placed
over the fastener to be removed and operation of the wrench can occur as
above.
Each of receiving areas 6, 16, 10, and 15 are cut into the centres of gear
wheels 11 and 31. The receiving areas are cut in such a way so as to
facilitate
the removal of damaged or rounded fasteners. In particular, each of receiving
areas 6, 16, 10, and 15 are cut into a number of arcs angled counter-
clockwise.
Figures 6 and 7 show receiving areas 6 and 15 cut into 6 such arcs (to match a
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sided fastener). When the receiving area is placed over the damaged fastener,
the intersections of the arcs cut into the fastener's flat faces and force the
fastener to turn when torque is applied to the handle 1 of the wrench. The
counter-clockwise angle of the arcs aids in facilitating the removal of the
fasteners. The number and angle of arcs is variable, depending on the type of
fastener that needs to be removed, and each of receiving areas 6, 16, 10, and
15
may be cut and sized differently so as to accommodate 4 different sizes and
shapes of fasteners.
The foregoing description illustrates only certain preferred embodiments of
the invention. The invention is not limited to the foregoing examples. That
is,
persons skilled in the art will appreciate and understand that modifications
and
variations are, or will be, possible to utilize and carry out the teachings of
the
invention described herein. Accordingly, all suitable modifications,
variations and
equivalents are intended to fall within the scope of the claims.
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