Note: Descriptions are shown in the official language in which they were submitted.
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CERTIFICATE OF MAILING BY EXPRESS MAIL
Express Mail mailing label number ER 605187754 US
I certify that this correspondence is being deposited with
the United States Postal Service "Express Mail Post Office
to Addressee" service under 37 C.F.R. 1.10 on the date in-
dicated below and is addressed to Commissioner for Patents,
Alexandria, VA 22313-1450
Heather Cruz-Santiago
(Typed or printed name of person mailing paper or fee)
Signature
Date of Deposit
DAMAGED BOLT AND SCREW
REMOVING DEVICES
This patent application claims the benefit of U.S. Provisional Patent
Application
No. 60/465,506, filed on April 25, 2003 and U.S. Utility Patent Application
No.
10/831,391 filed April 23, 2004.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of hardware tool bits, and more
particularly, the present invention relates to a device for removing damaged
fasteners
still embedded or otherwise engaged with a workpiece.
2. Description of the Prior art
The use of fasteners, such as screws, bolts, and other threaded joining
devices
continues to increase. However, the more a fastener is used, the more likely
that it
becomes rounded off, broken, or otherwise rendered useless. At that point, the
fasteners must be removed, and/or the workpiece replaced or abandoned.
A myriad of screw removing bits exist. Generally, the bits are typical in that
each
bit has a first end and a second end. The first end is adapted to be received
by a
rotating tool shaft, such as the shaft of a screw driver, either manually or
power-driven.
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The second end of the bit is configured to impart rotational torque to the
fastener while
the latter is still held fast by the workpiece.
The second end of the bit mimics the end of a standard drill bit. Several
broken
bolt extractors feature a left-handed cutting edge. For exampie, U.S. Patent
No.
4,777,850 discloses two such edges. However, such devices still require
considerable
power to impart the rotational torque necessary to "bite" into the fastener to
begin left-
handed extraction.
U.S. Patent No. 6,595,730 B2 awarded to Bergamo on July 22, 2003 discloses a
bit for removing damaged screws. This device is designed to engage the
exterior
surface of the fasteners and not interior surfaces of the fastener. As such,
"purchase"
of the fastener by the device is relegated to that exterior surface.
Another example of a prior art extraction device is the tool disclosed in
German
patent DE 19526631 Al. The tool depicts two cutting edges that drill a hole in
a
"frozen" screw/bolt or rivet when rotated in a first direction. The two
cutting edges also
are suitable for loosening the same fastener after drilling the hole in the
fastener
thereby providing a single tool that performs two functions to reduce the
extraction time
to remove a fastener from a workpiece. The problem with this tool is that a
recess must
be present in the fastener to better facilitate removal from the workpiece.
The German
tool cannot be used to remove a fastener having a slotted surface
configuration unless
the fastener includes a recess with a depth sufficient to allow the two
cutting edges to
insert therein. Otherwise, the slotted head fastener would be damaged during
removal.
A need exists in the art for a broken bolt or broken screw extraction device
to
facilitate easier removal of fasteners held tight by a workpiece. The device
should be
able to be utilized with hand-actuated handles or with electrically activated
(including
battery operated) tools. The device should engage as much of the interior
surface of a
wayward fastener so as to decrease the likelihood of a spin off of the device
from the
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fastener while concomitantly increasing the likelihood of extraction of the
fastener with
minimal force required.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a broken bolt or broken
screw
remover that overcomes many of the disadvantages of the prior art.
It is a further object of the present invention to provide a broken bolt/screw
remover that requires only low levels of torque to extract a fastener. A
feature of the
invention is that the fastener has a pair of generally radially projecting
cutting edges,
with each of the cutting edges defining an angle with respect to the axis of
the remover.
An advantage of the invention is that the different cutting edge angles
enhance the bite
of the bit into interior surfaces of the fastener. The cutting edges also can
contain
serrations running substantially perpendicular to the longitudinal axis of the
cutting edge
to provide additional purchase of the fastener. The serrations allow the bit
to effectively
extract wayward fasteners at torque speeds of as low as 0.25 RPM to as high as
typical
RPM values of commercially available electric screw drivers and power tools.
Hand-
actuated screw drivers for example are typically turned one quarter turn per
wrist roll
such that 30 RPM is typical for a non-powered hand tool.
Yet another object of the present invention is to provide a broken bolt/screw
remover which also has drilling function. A feature of the invention is that
it comprises a
left-handed countersink drill bit containing serrations which extend generally
longitudinal
to the axis of the bit. An advantage of the invention is that the drilling
feature of the
remover causes more interior surfaces of the fastener to be made available to
the
cutting edges of the serrations, and assures withdrawal of the remover with
the fastener
attached to the bit while the threaded cavity in the workpiece is left intact.
Still another object of the present invention is to provide a step drill with
fastener
remover capabilities. A feature of the invention is a plurality of generally
longitudinally-
extending serrations interposed between axially spaced steps in the drill bit.
These
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serrations extend in a left hand cutting fashion. An advantage of the
invention is that
this one embodiment can be utilized to extract fasteners having a myriad of
different
shank diameters.
Briefly, the invention provides a bit for removing a broken fastener having a
direction of engagement, said bit comprising an elongated shaft with a
longitudinal axis,
said shaft having a first end, and a second end, said first end terminating in
a tip; a
plurality of nonlinear cutting edges extending radially from said tip, said
cutting edges
configured to cut into the fastener when the bit is rotated in a direction
opposite to the
fastener's direction of engagement; and said second end of the shaft
configured to be
io received by a tool which provides rotational torque.
BRIEF DESCRIPTION OF THE DRAWING
The foregoing invention and its advantages may be readily appreciated from the
following detailed description of the invention, when read in conjunction with
the
accompanying drawing in which:
FIG. 1 aa is an elevational view of the invented bit, in accordance with
features
of the present invention;
FIG. 1 ab is a top view of FIG. 1 aa taken along the line 1 ab-1 ab;
FIG. lac is an elevational view of FIG. laa rotated 180 degrees around its
longitudinal axis, in accordance with features of the present invention;
FIG. I ba is an elevational view of the invented bit with serrated regions, in
accordance with features of the present invention;
FIG. 1 bb is a top view of FIG. 1 ba taken along the line 1 ba-1 ba;
FIG. 1 bc is an expanded view of the invented bit with serrated regions
depicted
in FIG. 1 ba, in accordance with features of the present invention
FIG. lca is an elevational view of an alternate invented bit with serrated
regions,
in accordance with features of the present invention;
FIG. 1 cb is a top view of FIG. 1 ca taken along the line 1 cb-1 cb;
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FIG. 1cc is an elevational view of an alternate invented bit with serrated
regions,
in accordance with features of the present invention;
FIG. 1cd is a top view of FIG. 1ca taken along the line 1cd-1cd;
FIG. 1 da is a detailed view of the serrated regions depicted in FIG. 1 ba, in
5 accordance with features of the present invention
FIG. 1db is a detailed view of an alternate configuration of the serrated
regions
depicted in FIG 1 ba, in accordance with features of the present invention;
FIG. 2a is an elevational view of an easy out bit further defining a left
handed drill
bit with serration portions, in accordance with features of the present
invention;
FIG. 2b is an expanded view of the cutting edge of FIG. 2a, in accordance with
features of the present invention;
FIG. 3a is a side view of a step drill bit with cutting threads, in accordance
with
features of the present invention;
FIG. 3b is a side view of an alternate step drill bit with serration portions,
in
accordance with features of the present invention;
FIG. 3c is a top view of FIG. 3b taken along the line 3c-3c;
FIG. 4a is a perspective view of an alternative fastener extraction device, in
accordance with features of the present invention;
FIG. 4b is a top view of FIG. 4a taken along the line 4b-4b;
FIG. 5a is a modified spade flat, in accordance with features of the present
invention;
FIG. 5b is an alternate modified spade flat, in accordance with features of
the
present invention;
FIG. 6a is an elevational view of a modification of the invented bit, in
accordance with features of the present invention;
FIG. 6b is a top view of FIG. 6a taken along the line 6b-6b.
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FIG. 7A is an elevation view of a extraction tool depicting non-linear cutting
surfaces, in accordance with features of the present invention;
FIG. 7B is an exploded view of figure 7A showing details of cutting-edge
serrations, in accordance with features of the present invention;
FIG. 8 is a view of FIG 7A taken along line 8-8.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a bit configuration and various bit/threaded
configurations on a single device to allow for easier fastener extraction.
FIG. 1aa provides salient features of the invented bit, the bit designated
to generally as numeral 10. As with any typical bit, the bit generally
comprises a shaft 12
with a first end 13 terminating in a tip 19. While the tip 19 is depicted as
generally
pointed, standard split tips also can be utilized such that the cutting
surfaces 14 are not
coplanarly aligned with each other or with the tip. This split point
configuration
minimizes and even prevents "walk out" of the bit from the workpiece. As such,
the
is configuration serves as a means for maintaining the bit on the fastener
during rotational
motion of the bit.
A second end 15 of the bit is configured to be received by a tool which
imparts
rotating torque, including but not limited to a chuck, or collet (or some
other means for
imparting torque). As such, a cross section of the second end can be circular,
20 hexagonal, polygonal or any convenient shape to facilitate the tip being
acted upon with
rotational torque.
The bit typically comprises two longitudinally extending notches 16, each of
the
notches terminated on one side with a leading or cutting edge 14. The other
side of the
notch is bounded by a noncutting edge 17. Both the cutting edge 14 and
noncutting
25 edge extend from a point proximal to the axis to the bit periphery. Only
one or more
than two extending notches are acceptable, but, for the sake of specificity,
the following
discussion will focus on two-notched configurations. The cutting edge 14 faces
in a
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counter-clock-wise direction for extracting a fastener with a clockwise
direction of
engagement and conversely for a counterclockwise fastener. Between the cutting
edge
and noncutting edge is a biting or traction-enhancing surface 18 which can be
described as a section of a frusto-conically-shaped region. The biting surface
is bound
by the cutting edge 14 and noncutting edge 17.
The cutting edge 14 defines an angle to the longitudinal axis of the bit. The
opposite side of the bit shown in FIG. 1 ac defines a very similar
configuration, except
that its cutting edge 14b is arranged at an angle () to the axis of the bit
that is different
than the angle . FIG. 1 ab is a top view of FIG. 1 aa taken along the line 1
ab-1 ab.
Surprisingly and unexpectedly, the inventor has found that the difference in
the
cutting edge angles facilitates greater bite into the shank of the broken
fastener. The
first angle can differ from the second angle by as much as 50 percent. For
example,
whereas the first angle is 45 degrees, the second angle is 30 degrees.
Ideally, the
sum of the angles is such that any remaining slot of a broken fastener can
simultaneously contact at least portions of each of the cutting edges 14 and
14b. While
the cutting edges depicted in FIG. 1 aa are rectilinear, in an alternative
embodiment the
cutting edges define a spiral configuration oriented opposite to the
fastener's direction
of engagement.
As an alternative to the bit having a straight cutting edge 14b as depicted in
FIGS 1aa and 1ac, one of the edges 14a or more edges can be serrated, curved
or
both. Serrated edges are depicted in FIG. 1 ba. (FIG. 1 bb is a top view of
FIG. 1 ba
taken along the line 1 bb-1 bb.) The serrations 15 start along at least a
substantial length
of the cutting edge, and extend transversely from the cuffing edge in a right
handed
direction (i.e. opposite the direction of the small arrow labeled B, and
circumferentially
parallel to the periphery of the bit. The serrations can extend completely
across the
frusto-conical surface 18 so as to terminate on the noncutting edge 17 (See
FIGS 1 ba
and 1ca) , or else the serrations can stop on the surface 18 between the
cutting edge
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14 and noncutting edge 17 (See FIG. 1 cc and FIG1 cd which is a top view of
FIG. 1 cc
taken along the line 1 cc-1 cc). The serrations define on the surface 18 a
series of teeth
15 with gaps 19 between the teeth, as shown in the detail in FIG. 1 bc. A
device with
more than one ing surface with serrations provides additional purchase synergy
as
discussed infra.
FIG. 1ca is analogous to FIG. lac except it is the biting surface at an angle
with
respect to the axis that bears the serrations FIG. lcb is a top view of FIG.
1ca taken
along the line 1 cb -1 cb.
The inventors have found that having one cutting edge serrated, and the
to immediate next cutting edge smooth enhances "bite" of that smooth cutting
edge into
the fastener for easier extraction from the workpiece. This alternating
serrated/smooth
cutting edge configuration provides a double action whereby the serrated edge
roughens the topography of the fastener surface, thereby serving as a means
for
enhancing purchase of the smooth cutting surface with the fastener.
A plurality of cutting edges on the same bit can be serrated (even on adjacent
edges as opposed to a smooth edge intermediate two serrated edges), with one
configuration having edges biting into the fastener at different axial
locations from each
other. The inventive feature of varying the angle of attack of the edges
(e.g., the angles
and , discussed supra) will minimize the possibility of adjacent serrated
edges
destroying the carcass of the fastener before the bit can anchor into the
carcass for
removal.
There are many possible variations in the configuration of the serrations. For
instance, a possible embodiment is where serrations are provided on two
cutting edges
that are at the same angle with respect to the bit axis, with the serrations
defining two
sets of teeth 15 with separated by gaps 11. FIGS 1 da and 1 db depict two
possible
variations within this embodiment. In FIG 1da corresponding teeth 15a'-15b',
15a"-15b",
15a"'-15b"', etc ... on the two surfaces are azimuthally aligned across a
notch 16 while
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in FIG 1db corresponding teeth are axially displaced with respect to those on
the other
side of the notch so as to be azimuthally aligned with the gaps 11 on the
other side.
The staggered serration configuration provides a means for serrations biting
at different
radial and axial regions of the fastener. In other words, serrations which are
s azimuthally aligned with each other are those serrations which are
positioned the same
radial distance from the longitudinal axis of the bit.
Furthermore, it should be noted that the invented bits need not terminate into
a
sharp apex. Rather, bits terminating in rounded or blunted apexes are suitable
for
fasteners having particularly large-diameter shanks or for fasteners where a
central
io cavity has been fashioned during a previous attempt to extract the
fastener. FIG 6a
depicts an exemplary embodiment of such a blunted apex bit where the biting
surfaces
18 are inclined at different angles with respect to the axes (See FIG. laa)
and may also
comprise serrations (See FIG. 1 ba). FIG. 6b is a top view of FIG. 6a taken
along the
line 6b-6b.
15 FIG. 2a depicts an embodiment of the invented broken fastener remover,
designated as numeral 20, which comprises a standard "easy out" configuration
(whereby the easy out defines a tapering, left handed spiral). This embodiment
comprises a plurality of left-handed cutting surfaces 22 terminating in a
drill bit 28. The
bit 28 can have the configuration described in FIGS laa and 1ba.
20 Also, the fastener remover bit 20 with the easy out configuration can
include a
plurality of serrations 24 along the cutting surface(s) 22 of the bit 20,
these cutting
surfaces defining helical regions extending circumferentially along the
periphery of the
bit 20. The serrations can exist along one or more than one of the cutting
edges 14 of
the bit. A salient feature of this embodiment is a plurality of left hand
serrations 24
25 which extend preferably (but not necessarily) parallel to the longitudinal
axis of the
shank 12 of the bit. These serrations bite in to the recess of the screw head.
FIG. 2b
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depicts a detail of a cutting edge 14 showing that the serrations 24 define
teeth 25 on
the cutting edge 14 of the spiral cutting surface 22.
FIGS. 3a and 3b depict a fastener removal bit designated as numeral 30. This
removal bit 30 has a first end 31 adapted to be received by a rotating handle
or chuck,
5 or collet (not shown). A second end 32 of the removal bit 30 terminates in a
bit
configuration 39 similar to that depicted in FIGS. 1aa-1ba. Generally, the
cutting region
of the removal bit comprises a step drill configuration 32 and serration edges
33
positioned intermediate the steps 34 of the configuration such that the
serrations extend
radially from radially-facing surfaces of the steps. Also, these serration
edges 33
lo generally extend parallel to the longitudinal axis of the bit 30, defining
a left hand
(counter-clockwise) drill cutting configuration.
In FIG. 3a, the steps 34 are axially spaced and otherwise arranged so that
various fastener shank diameters can be accommodated with the removal bit 30.
As
such, steps have self-tapping screw threads 37 which are spaced apart to
provide the
is anchoring necessary to withdraw the fastener in an axial direction once the
bit is buried
into the fastener shank, while the threaded cavity in the workpiece is left
intact.
FIG. 3b depicts an alternative step drill bit 73, wherein the steps 34 are
configured to comprise counter-clockwise cutting edges 74 and biting surfaces
78.
More specifically, the bit 73 has a first end that terminates in a tip 72 with
two or more
notches 71 extending longitudinally along the shaft 31 from the tip, said
notches
separated by a plurality of cutting edges 79, said edges 74 arranged on biting
surfaces
75 which are positioned along the axis and successively radially displaced
further from
the axis in a direction from the first end to the second end. The cutting
edges are 79
configured to cut into the fastener in progressive radial steps when the bit
is rotated in a
direction opposite to the fastener's direction of engagement at the same time
as the
cutting edges cut azimuthally into the fastener. Depending regions of said
surfaces 75
comprise a plurality of teeth 76, each of said teeth defining one cutting edge
74
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adapted to bite the fastener in a direction along the longitudinal axis of the
fastener.
Thus each of the steps 34 constitutes a hole saw that bites into the fastener
as the drill
bit advances into the fastener. FIG. 3c is a view of FIG. 3b taken along line
3c-3c. The
embodiment described in FIG. 3b may also comprise features described in
conjunction
with the embodiments described in FIGS 1 aa and 3a. Thus the bit 73 may
comprise
serration edges protruding from said surfaces 75 and self-tapping screw
threads on one
or more of said surfaces. Also, two or more cutting edges 79 may have
dissimilar
angles with respect to the axis.
FIG. 4a depicts another bit, designated generally as numeral 40 and FIG. 4b is
a
io top view of FIG. 4a taken along the line 4b-4b. This bit comprises a "glass
drill" 44 in
the shape of a solid rod, terminating with a carbide insert 42. The insert 42
consists of
a 2-notch bit as depicted in FIGS. 1 aa and 1 ba in the limit where each of
the notches
43 is between 150 and 180 degrees. Thus the present embodiment resembles a
flat
"spade" bit positioned transversely to the longitudinal axis of the rod. The
distal end of
ts the insert defines a plurality of left handed cutting edges 14, each which
may or may
not be at the same angle relative to the longitudinal axis of the rod.
Optionally, one or
both of these edges define biting surfaces that contain serrations 15
extending
transversely from the cutting edge. Each of these edges are configured in a
left handed
configuration, so that right-hand fasteners are extracted thereby. However,
and with all
20 bits depicted herein, the cutting edges can be configured as right-hand
facing so as to
facilitate removal of left-handed fasteners. FIG. 4b is a view of FIG. 4a
taken along line
4b-4b.
The invented screw/bolt remover configuration can be integrally molded with
other typical tool bits. For example, and as depicted in FIG. 5a, elements of
the
25 invented configuration depicted in FIGS. laa and 1ba can be integrally
molded with a
typical spade flat bit (FIG. 5a is a view of spade flat shown in slot of
broken fastener) to
optimize an already familiar tool. A typical spade drill comprises a shank
adapted to be
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received in the chuck, or collet of a torque-imparting tool, the shank
terminating in a flat
cutting element often called a "spade flat." The spade flat typically
comprises cutting
edges parallel to the shank and a cutting tip aligned with the shank and/or
side cutting
tips parallel to the shank but laterally displaced from the axis of the shank.
In FIGS 5a and 5b the spade flat hybrid 50 is depicted as positioned at the
slot of
a broken screw 54, the screw countersunk into a workpiece 56. In operation,
the
cutting edges 14 of the spade flat hybrid 50 burrow into the head 58 of the
screw. The
center of the slot of the screw is shown as a pilot hole for the user of the
hybrid bit 50.
In Fig. 5a the invented hybrid tool, designated as numeral 50 defines cutting
edges 14 in a counter-clockwise facing position of the spade flat 52 and on a
tip 51
similar to either of the configurations depicted in FIGS. 1 aa and I ba. The
bit 50 also
comprises side cutting tips 53.
In Fig. 5b the spade flat terminates in a triangular cutting element 59.
As with the embodiments depicted in FIG. 1, the spade flat can alternatively
include a non-cutting edge and a biting surface, having either a smooth or
serrated
topology.
The spade flat depicts a 1/4" size. However, this is for example only. Rather,
a
myriad of spade flat sizes are suitable, depending on the diameter of the
residual
fastener head 58 or shank remaining.
Another embodiment of a spade flat is depicted in FIG. 5b where the cutting
edges 14 assume a triangular shape.
It should be noted that the above described embodiments all depict left handed
cutting configurations. However, if left handed fasteners are to be removed,
then the
herein disclosed embodiments with right handed cutting configurations would be
utilized.
It should be further noted that the opposed cutting edges in each of the above-
disclosed embodiments generally are configured at angles to the longitudinal
axis of the
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respective bit which are either identical to each other, or different from
each other, on
the same bit.
As mentioned supra, the cutting 14 and non-cutting edges 17 of the bit can be
curved (i.e., nonlinear), as depicted in FIGS. 7 and 8. Referring to the top
elevation
view of FIG. 8, the first and second nonlinear cutting edges 14a and 14b
cooperate with
the first and second non-cutting edges 17a and 17b to form angles A and B
which
correspond to the radial arc of the notches 32, 34. The notches 32, 34 are
shaped and
reminiscent of the flutes or relief surfaces of left hand drill bits. While
the flutes of the
illustrated embodiment extend generally along a straight line and
longitudinally and
parallel to the longitudinal axis of the bit, curved flutes are also suitable
variants. Such
flutes define an extended helix or spiral along a longitudinally extending
section of the
periphery of the bit and about its circumference. These curved flutes are
further
defined by serrations along their edges or rims which face in a direction the
bit is to be
rotated to extract fasteners. Thus, for job requiring extraction of right-hand
fasteners,
the serrations would be found on flute edges which face in a counterclockwise
direction.
As with the cutting and noncutting edges of the other embodiments in this
invention, the cutting and noncutting edges define a frusto-conical surface of
the bit
such that the surface lies intermediate the cutting and respective noncutting
edge.
Although FIG. 8 depicts angles A and B having equal magnitudes, the angles A
and B
subtended by the notches respectively may vary to cooperate with design or
damaged
configurations of the slot portions of the fastener 18. This substantially
congruent
engagement results between the first and second extending notches of the
fastener
engagement end 16 and the slot portions of the fastener to provide increased
torque
from the tool 10 to the fastener.
Also, where serrations 36 are provided on the curved cutting surfaces, such
serrations may be lineal, arcuate, segmented, radial or combinations thereof.
Further,
when the serrations 36 include a lineal configuration, the longitudinal axis
of the
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serrations 36 may be orientated perpendicularly, parallel or inclined to the
longitudinal
axis of the tool 10. (See FIG. 7B.)
Optionally, instead of, or in addition to the serrations extending across the
fastener engaging surfaces 24, 26, serrations 36 also are provided which
extend along
interior wall portions 33, 35 of the notches 32, 34 from the corresponding
cutting edges
20, 22. As with the serrations extending across the fastener engaging surfaces
24, 26,
the serrations 36 may extend across only a portion of the wall portions to
both enhance
engagement with a corresponding slot portion of the fastener 18 and maintain
structural
integrity of the tool 10.
Also, the invented bits can be configured to include a means for preventing
the
bits from dislodging from broken fasteners once engagement with said fasteners
occurs. In this regard, "finders" may be installed. These are accessories
associated
with, and co-axial to, the shanks of the bits and in slidable communication
therewith.
Generally configured as cylinders or tubes, the finders are adapted to slide
over the
1s periphery of a fastener which is held fast in a work piece. As such, the
finders maintain
the bit in a position coaxial to the longitudinal axis of the fastener to
assure adequate
embedding of the bit into the fastener. The finder also prevents jumping or
skipping of
the bit from the fastener to adjacent surfaces of the workpiece, thus
preventing marring
or scuffing of said workpiece.
Another addition to the invented device is the positioning of a collar or
radial
projection about the circumference of the device. The collar or projection
would be
positioned intermediate the first and second end of the device and serve as a
means
for preventing penetration of the device into the fastener beyond the distance
defined
by the tip 19 of the device and the position of the collar.
While the invention has been described in the foregoing with reference to
details
of the illustrated embodiment, these details are not intended to limit the
scope of the
invention as defined in the appended claims.
