U.S. patent application number 11/623051 was filed with the patent office on 2008-07-17 for grinding assemblies for use with handheld power tools.
Invention is credited to Mark Tretter, Dennis Clifford Woods, Dennis David Woods.
Application Number | 20080171498 11/623051 |
Document ID | / |
Family ID | 39361359 |
Filed Date | 2008-07-17 |
United States Patent
Application |
20080171498 |
Kind Code |
A1 |
Woods; Dennis David ; et
al. |
July 17, 2008 |
Grinding Assemblies for use with Handheld Power Tools
Abstract
Grinding assemblies for use with handheld power tools are
disclosed herein. More specifically, the assemblies disclosed
herein can include a hub, disc, grinding surface and locking nut
and can be used with most available handheld grinders for grinding
flat surfaces.
Inventors: |
Woods; Dennis David;
(Escondido, CA) ; Woods; Dennis Clifford;
(Murrieta, CA) ; Tretter; Mark; (Escondido,
CA) |
Correspondence
Address: |
BAUMGARTNER PATENT LAW
4370 NE HALSEY ST, STE #124
PORTLAND
OR
97213
US
|
Family ID: |
39361359 |
Appl. No.: |
11/623051 |
Filed: |
January 12, 2007 |
Current U.S.
Class: |
451/342 ;
451/511 |
Current CPC
Class: |
B24B 23/00 20130101;
B24D 9/085 20130101; B24B 45/003 20130101 |
Class at
Publication: |
451/342 ;
451/511 |
International
Class: |
B24B 45/00 20060101
B24B045/00; B24D 13/20 20060101 B24D013/20; B24D 9/08 20060101
B24D009/08; B24D 7/16 20060101 B24D007/16 |
Claims
1. A grinding assembly for attachment to a rotating spindle on a
handheld power tool, comprising: a hub having a vertically
traversing channel opening to a topside and underside of said hub
and configured to attach to said rotating spindle, and wherein said
underside of the hub includes a concave recess; a disc having a
substantially planar topside and underside surrounding a
concavo-convex frustum having an aperture and configured to conform
to said concave recess on the underside of the hub, such that said
aperture aligns with the underside opening of the hub; and a
locking nut having a top-opening hollowed shaft connected to a base
having a solid back, wherein said shaft is configured to fit
through the disc aperture and the underside opening of the hub to
attach to said rotating spindle such that the back of the locking
nut is within the concave recess of the hub and does not protrude
past the substantially planar underside of the disc.
2. The grinding assembly of claim 1, further comprising a grinding
surface configured to be attached to said disc.
3. The grinding assembly of claim 2, wherein said grinding surface
is attached to said disc by said locking nut.
4. The grinding assembly of claim 1, wherein the hub includes a
plurality of grooves around an outer surface.
5. The grinding assembly of claim 4, wherein the hub comprises
bean- shaped grooves on said outer surface.
6. The grinding assembly of claim 1, wherein said concavo-convex
frustum comprises a plurality of slots around said aperture.
7. The grinding assembly of claim 1, wherein said vertically
traversing channel in said hub, is partially threaded at a thread
count of 11 threads per inch.
8. The grinding assembly of claim 1, wherein the underside of the
hub includes a flat outer periphery.
9. A hub for attachment to a rotating spindle on a handheld power
tool, comprising a stem connected to a base having a concave
recessed underside, wherein a central aperture configured to attach
to said spindle vertically traverses from a topside opening of said
stem and opens to the underside of the base, and wherein said base
includes a plurality of grooves on an outer surface.
10. The hub of claim 9, wherein said base is shaped as a truncated
cone.
11. The hub of claim 9, wherein the aperture is threaded.
12. The hub of claim 11, wherein said aperture comprises a thread
count of 11 per inch.
13. The hub of claim 9, wherein said plurality of grooves are
bean-shaped.
14. The hub of claim 9, wherein said underside comprises a
substantially flat outer periphery that surrounds said concave
recess.
15. An assembly for attachment to a rotating spindle on a handheld
power tool, comprising: a hub having a vertically traversing
aperture opening to a topside and underside of said hub and
configured to attach to said rotating spindle, and wherein said
underside of the hub includes a concave recess; and a locking nut
comprising a back end and a shaft, wherein said shaft is configured
to fit through the underside opening of the hub to attach to said
rotating spindle such that the back end of the locking nut fits
within the concave recess of the hub.
16. The assembly of claim 15, wherein said back end of the locking
nut comprises a solid back.
17. The assembly of claim 15, wherein said vertically traversing
aperture and said rotating spindle are threaded such that said hub
can be screwed onto said rotating spindle.
18. The assembly of claim 17, wherein said vertically traversing
aperture includes a top section that is threaded such that said hub
can be screwed onto said rotating spindle and a smooth bottom
section configured to receive said shaft of the locking nut.
19. The assembly of claim 15, wherein said hub includes a stem and
a base in the shape of a truncated cone.
20. The assembly of claim 18, wherein said base includes a flat
surfaced underside.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to grinding
assemblies and attachments for use with a handheld power tool, such
as an angle grinder. In general grinding assemblies and the
attachments described herein can be used to more easily smooth hard
surfaces and alleviate dust build up on the power tool.
BACKGROUND
[0002] In the construction and remodeling industry, after concrete
foundation is laid and hardened, it is still rough and needs to be
smoothed. Large grinders are generally used to smooth out rough
concrete floors and working areas, see U.S. Pat. No. 5,908,224, to
Santos. The grinding surfaces of many grinders designed for large
working surfaces are often configured such that they cannot
adequately grind close to a wall or other obstruction. Users of
these large grinders typically need to provide adequate clearance
between the devices's grinding surface and the wall or obstruction.
This disadvantageous design leaves an unfinished or rough working
surface area near the wall or obstruction. In addition, large
grinders are difficult to move. They are especially difficult to
move up stairways in order to smooth upper level floors. For the
above reasons, it can be advantageous to utilize a smaller,
handheld grinder having a flat grinding surface that is capable of
accessing floors and working areas that are otherwise difficult to
grind.
[0003] However, designs for many handheld grinder attachments are
problematic. For example, many handheld grinders have a rotating
grinding surface attached by a nut that protrudes past the plane of
the grinding surface. This design is disadvantageous for grinding
flat surfaces, such as floors, because the grinding surface of the
grinder must be used at an angle. If a user laid the grinding
surface flat against the working surface, the protruding nut would
be grinded down. Grinding a flat surface at an angle with a
handheld grinder is also problematic as it will cause the rotating
grinding surface and/or underlying disc pad to warp. Accordingly,
this technique places excessive stress on the grinding surface
quickly and requires the user to replace the grinding surface
frequently.
[0004] Further problems with current grinders is that many utilize
a rubber or low-grade plastic disc pad that wears down easily,
creates wobble when grinding, and also results in the user
replacing the grinding surfaces frequently.
[0005] Additional problems are created when the nut, grinding
surface, or underlying disc pad are configured to have an opening
facing the working surface that allows dust created from the
grinding to enter into the rotating spindle. Minimizing the amount
of dust contacting the spindle is highly desirable because the dust
can quickly build up and harden, thus making it difficult to detach
and attach parts to the grinder. Dust can also cause damage to the
spindle.
[0006] An additional problem with conventional handheld grinders
and attachments is that they are susceptible to overheating because
they do not have an adequate cooling system for their rotating
parts. A further problem of previous grinding attachments is that
they are not configured to be attached to most available handheld
grinding units.
[0007] Accordingly, there is a need in the art to provide grinding
assemblies for handheld grinders that minimize the above problems
associated with conventional grinder attachments. Accordingly, one
object of the invention is to provide new and improved grinding
assemblies that are durable and can be used flush against flat
working surfaces. A further object of the invention is to provide
grinding assemblies that minimize dust from contacting the rotating
spindle. Still a further object of the invention is to provide
grinding assemblies that cool the rotating parts and grinder as it
rotates. Still a further object of the invention is to provide
grinding assemblies that are capable of being universal, such that
it can attach to most, if not all, available handheld grinders.
SUMMARY OF THE INVENTION
[0008] According to certain embodiments, the teachings herein
disclose grinding assemblies for handheld grinders. In certain
embodiments, the grinding assemblies are configured to be used
against a flat working surface, such as a floor, for example. In
further embodiments, the grinding assemblies help prevent dust from
contacting and collecting on the rotating spindle. In other
embodiments, the grinding assemblies provided herein are configured
to cool the rotating parts and the grinder as it grinds. In still
further aspects, the grinding assemblies described herein can be
attached to and used with most, if not all, manufactured handheld
grinders.
[0009] The teachings herein are directed to grinding assemblies for
attachment to a rotating spindle on a handheld power tool, and
include a hub having a vertically traversing channel opening to a
topside and underside of said hub and configured to attach to said
rotating spindle, and wherein said underside of the hub includes a
concave recess, a disc having a substantially planar topside and
underside surrounding a concavo-convex frustum having an aperture
and configured to conform to said concave recess on the underside
of the hub, such that said aperture aligns with the underside
opening of the hub, and a locking nut having a top-opening hollowed
shaft connected to a base having a solid back, wherein said shaft
is configured to fit through the disc aperture and the underside
opening of the hub to attach to said rotating spindle such that the
back of the locking nut does not protrude past the substantially
planar underside of the disc.
[0010] According to preferred embodiments, the grinding assemblies
provided herein can further include a grinding surface configured
to be attached to said disc, such as through a locking nut, for
example. According to further embodiments, the hub includes a
plurality of grooves around an outer surface, such as bean-shaped
grooves, for example. In other more specific aspects, the grinding
assemblies provided herein can include a concavo-convex frustum
that includes a plurality of slots around said aperture.
[0011] In other preferred aspects said vertically traversing
aperture in said hub, is partially threaded at a thread count of 11
threads per inch and is configured to screw onto a spindle having a
5/8 inch diameter. Other preferred aspects relate to the underside
of the hub having a flat outer periphery.
[0012] Further embodiments are directed to a new improved hub for
attachment to a rotating spindle on a handheld power tool, having a
stem connected to a base having a concave recessed underside,
wherein a central aperture configured to attach to said spindle
vertically traverses from a topside opening of said stem and opens
to the underside of the base, and wherein said base includes a
plurality of grooves on an outer surface.
[0013] In more specific embodiments, the base is shaped as a
truncated cone. In further embodiments, the aperture is partially
threaded, such as a thread count of 11 per inch. In other
embodiments the hub can include bean-shaped grooves, for example.
The hub's underside can also include a substantially flat outer
periphery that surrounds said concave recess.
[0014] Further embodiments are directed to assemblies for
attachment to a rotating spindle on a handheld power tool, and
including a hub having a vertically traversing aperture opening to
a topside and underside of said hub and configured to attach to
said rotating spindle, and wherein said underside of the hub
includes a concave recess; and a locking nut comprising a shaft
configured to fit through the underside opening of the hub to
attach to said rotating spindle such that the locking nut fits
within the concave recess of the hub. In even more preferred
embodiments, the locking nut has a solid back.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] It will be appreciated that the drawings are not necessarily
to scale, with emphasis instead being placed on illustrating the
various aspects and features of embodiments of the invention, in
which:
[0016] FIG. 1 is an exploded view of one embodiment of a preferred
grinding assembly and an angle grinder.
[0017] FIG. 2 is an angled view of a preferred hub of a grinding
assembly.
[0018] FIG. 3 is an angled view of a preferred locking nut of a
grinding assembly.
[0019] FIG. 4 is an angled view of a preferred disc of a grinding
assembly.
[0020] FIG. 5 is a cross-sectional view of a spindle secured to a
hub and locking nut.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0021] Embodiments of the present invention are described below. It
is, however, expressly noted that the present invention is not
limited to these embodiments, but rather the intention is that
modifications that are apparent to the person skilled in the art
and equivalents thereof are also included.
Grinding Assemblies
[0022] In preferred embodiments, the teachings herein are directed
to new and improved grinding assemblies for use with a handheld
angle grinder. Embodiments of the invention will now be described
with reference to the accompanying figures, wherein like numerals
refer to like elements throughout. The terminology used in the
description presented herein is not intended to be interpreted in
any limited or restrictive manner simply because it is being
utilized in conjunction with a detailed description of certain
specific embodiments of the invention.
[0023] FIG. 1 provides a particular advantageous embodiment of a
handheld grinder 2 and a grinding assembly. According to this
preferred non-limiting embodiment, the grinding assembly typically
includes four pieces: a hub 20, a disc 30, grinding surface 40, and
a locking nut 50. Other grinding assemblies provided herein can
include fewer or more pieces.
Handheld Grinder
[0024] The grinding assemblies described herein can be coupled to
available handheld grinders or other power tools having with a
rotating spindle. FIG. 1 depicts one embodiment of an angle grinder
that is compatible with the assemblies provided herein. Those with
skill in the art will readily recognize that most available
grinders can be used with the teachings herein. The assemblies are
not limited to being attached to the specific grinder depicted in
FIG. 1. The angle grinder in FIG. 1 includes an extension cord 14
compatible with an electrical outlet, a handle 8, an ON/OFF trigger
4, a housing 12 that includes an electric motor, a gear box 16, and
a rotatable spindle 6 for connecting to a grinding assembly or
other attachment. In general, a power source provides power to the
electric motor that in turn drives the appropriate gears configured
to rotate the spindle 6. Although not depicted in FIG. 1, many
angle grinders that can be used with the teachings herein often
have a second handle that protrudes from the side of the housing 12
or gearbox 16.
[0025] In preferred embodiments, the grinding assemblies provided
herein are attached to the threaded spindle 6 of the grinder 2.
While spindle length can vary according to different models of
angle grinders, the current standard in the industry for many
spindles is a thread count of 11 per inch and a 5/8 inch diameter.
Accordingly, in preferred embodiments, and as will be discussed in
more detail below, the grinding assemblies provided herein are
configured to attach to spindles with this standard thread count
and diameter, regardless of the spindle's length. Those with skill
in the art will readily appreciate that the dimensions of the
grinding assemblies described herein can readily be adapted to
attach to non standard, or unique spindles having differing thread
counts, diameters and lengths, including diameters of 1/4 inch and
3/8 inch, for example.
[0026] The grinding assemblies described herein can be used with
any suitable handheld power tool or grinder, non-exclusively
including an angle grinder. Non-exclusive examples of handheld
grinders that the grinding assemblies described herein can be used
with include those disclosed in Design Pat. No. D522,826 to
Aglassinger, U.S. Pat. No. 6,632,128, to Berger et al., and U.S.
Pat. No. 6,120,362 to Etter et al., and D527,966 to Hayakawa et
al., for example. All of these patents are expressly incorporated
herein by reference in their entireties.
[0027] In preferred embodiments, the handheld power tools, to be
used with the grinding assemblies provided herein are sufficiently
lightweight, such that they can be lifted by a user's hands and be
easily moved from one working area to another. While preferred
embodiments herein are directed to the terms "grinder" and
"grinding", the assemblies described herein can be configured with
any suitable power tool to smooth a workable surface, including
tools commonly referred to as sanders. Nonexclusive uses of the
assemblies provided herein include grinding concrete, drywall,
plastics, fiberglass, hybrid materials, and sanding wood, for
example. In more specific embodiments, the assemblies herein can be
used to smooth flat working surfaces, such as floors, including
rough, unfinished concrete floors, for example.
Hub
[0028] In preferred embodiments, the hub 20 includes a stem 22 and
a base 28 in the shape of a truncated cone. In advantageous
aspects, the stem 22 is configured to connect with the threaded
spindle 6 of the handheld grinder 2 such that the spindle 6
functions as an axis upon which the hub 20 rotates around. In
preferred embodiments, the hub's stem 22 includes an aperture 24
(or channel) that continues through the base 28 and opens to the
underside of the hub 20. In more specific aspects, the aperture 24
includes threads 25 configured to screw onto the threads of the
spindle 6. In even more specific embodiments, the aperture 24 has a
thread count of 11 threads per inch, and is configured to screw
onto spindles having a 5/8 inch diameter, the standard thread count
and diameter for many spindles in the industry. Skilled artisans
will recognize that the dimensions of the hub and its components
described herein can readily be adapted to attach to spindles
having differing thread counts, diameters and lengths, including
diameters of 1/4 inch and 3/8 inch, for example.
[0029] In more specific embodiments, the bottom of the aperture 24,
opening to the underside of the hub 20, is configured to receive
the shaft 52 of a locking nut 50. According to even more specific
embodiments, it is preferred that the aperture 24 is not entirely
threaded. It is instead preferred that the top of the aperture has
between 2, 3, 4, or 5 threads 25, and the bottom of the aperture
has a non-threaded or smooth section to receive the shaft 52 of the
locking nut 50. According to this preferred embodiment, the locking
nut 50 is not screwed into the aperture 24, but slid into it. This
smooth section in the aperture can preferably correspond to the
approximate height of the locking nut's shaft 52, and can
non-exclusively be approximately 7/8 or or 1 inch in height, in
advantageous aspects.
[0030] FIG. 5 depicts the shaft 52 of a preferred locking nut 50
securing a spindle 6 within the aperture 24 of a hub 20. This
depiction is provided only to show a general view of how the
locking nut 50 secures the rotating spindle 6. In preferred working
embodiments, the grinding assembly could include a disc 30 and a
grinding surface 40 secured between the hub 20 and the locking nut
50.
[0031] The underside of the hub preferably includes a generally
flat surfaced periphery 27 and an inner concave recess 23. More
specifically it is preferred that they are both concentric to the
aperture 24, in the middle of the underside of the hub 20. The
generally flat-surfaced periphery 27 is preferably approximately
1/8 inch in width (measuring from the outer rim of the base towards
the aperture 24), but can be any suitable distance non-exclusively
including approximately 1/16, 3/16, 1/4, inches, for example. The
concave recess 23 preferably recesses (rises) towards the center
aperture 24. In preferred embodiments, the concave recess 23 is
configured to conform to the shape of the frustum center 36 on the
topside of the disc 30 such that the periphery 27 of the hub lays
level on the topside 34 plane of the disc 30. In even more
preferred embodiments, the concave recess 23 rises toward the
aperture at a 25 degree angle. In further embodiments, the concave
recess can rise at various other angles including the approximate
range of 15-60 degrees (e.g., 15, 20, 30, 35, 40, 45, 50, and 55
degrees).
[0032] Those with skill in the art will readily appreciate that the
aperture's 24 height, diameter and/or thread count can be modified
to accommodate other spindles having non-standard thread counts and
diameters. Similarly, the hubs and locking nuts described herein
can attach to a particular rotating spindle by any suitable means
available.
[0033] In preferred embodiments, the base 28 of the hub 20 includes
grooves 26 for enhancing airflow. These embodiments are desirable
as they help alleviate dust build up within the grinder and its
components, including the bearings, for example. The grooves are
also helpful for cooling down the grinder and its components. While
any suitable shape of groove capable of enhancing air flow can be
used with the hubs provided herein (e.g., circular, rectangular,
elliptical, square, curved), in preferred embodiments, the grooves
26 are rounded and curved as depicted in FIG. 2. The shape of the
grooves shown in FIG. 2 will be referred to as "bean-shaped" for
simplicity. In more specific embodiments, the hub can include 1, 2,
3, 4, 5, 6, 7, 8, 9, 10, or more grooves capable of enhancing air
flow. In more preferred embodiments, the hub 20 includes six
bean-shaped grooves 26 around the base 28.
[0034] In more specific aspects, the hub-enhanced air flow can work
in conjunction with a hood cover and vacuum system that is coupled
to the grinder to remove the generated dust. In general, a vacuum
system sucks out grinder-generated dust and includes a hose in
working operation with the handheld grinder.
[0035] The hub 20 can be of any suitable height to accommodate a
particular length spindle. In preferred non-exclusive embodiments
the hub 20 has a total height from its underside periphery 27 to
the top of the stem 22 of approximately 1 and 5/8 inches. In other
preferred non-exclusive embodiments, the diameter of the underside
of the base 28 is approximately 2 and 1/2 inches.
[0036] The hub 20 can be made of any suitable metal, alloy, or
plastic, but in preferred embodiments, the hub 20 is made out of
steel, aluminum, or high-grade plastic. Metals and alloy based
parts can be manufactured according to any suitable technique in
the art, including but not limited to casting (e.g., investment or
die casting). Aluminum is a particularly desirable material to be
used with the hub 20 as it can dissipate heat evenly and
quickly.
Disc
[0037] In preferred embodiments, the grinding assemblies described
herein include a disc 30 that acts as a support backing for the
grinding surface 40. In other preferred embodiments, the disc 30
contains a generally flat topside 34 and underside 32 with the
exception of a concavo-convex frustum center 36. In more specific
embodiments, the center frustum 36 is raised (convex) on the
topside of the disc 30 and is recessed (concave) on the underside
of the disc 30. In more preferred embodiments, the topside of the
frustum 36 is configured to conform to the concave recess 23 of the
hub 20. In more advantageous embodiments, the topside of the
frustum 36 is raised at a 25 degree angle. In further embodiments,
the frustum can rise at various other angles including the
approximate range of 15-60 degrees (e.g., 15, 20, 30, 35, 40, 45,
50, and 55 degrees).
[0038] In still further embodiments, the frustum 36 contains an
aperture 38 that aligns with the hub's aperture 24, such that the
shaft 52 of the locking nut 50 can fit through both apertures (38
and 24). In more specific embodiments, the disc's aperture 38 can
be approximately 3/4 inch in diameter.
[0039] In certain embodiments, the frustum can be a solid piece
without slots (not shown), in other embodiments, the frustum can
include slots 37 that separate multiple wedges 39. These slots 37
allow the disc 30 to have more flexibility during grinding, such
that it minimizes stress resulting from a quickly rotating spindle
6.
[0040] In certain embodiments, the disc 30 is configured to be
secured between the hub 20 on its topside and the grinding surface
40 and locking nut 50 on its underside. In further embodiments, the
top of the frustum 36 is configured to fit within the concave
recess 23 on the underside of the hub, while the hub's outer
periphery 27 lays level on the top flat surface 34 of the disc 30.
Under this preferred configuration, when the spindle 6 is screwed
into the threads of the hub 20 and the locking nut 50, the disc 30
is secured between the two pieces.
[0041] In other preferred embodiments surface of the disc 30 is
relatively thin, having a thickness of approximately 1/16 of an
inch. Other non-exclusive approximate thickness can include 1/8 and
3/16 of an inch, for example. Skilled artisans will recognize that
the dimensions of the disc 30 provided herein can readily be
adapted to accommodate different dimensions of spindles, locking
nuts, grinding surfaces, and hubs.
[0042] In advantageous embodiments, the disc 30 can be made of any
suitable metal, alloy, or plastic, but in preferred embodiments,
the disc 30 is made out of steel, aluminum or high-grade plastic.
Metals and alloy based parts can be manufactured according to any
suitable technique in the art, including but not limited casting
(e.g., investment or die casting). Aluminum is a particularly
desirable material to be used with the disc 30 as it can dissipate
heat evenly and quickly.
Grinding Surface
[0043] The grinding assemblies provided herein can be used to
smooth any hard surface including concrete, asphalt, wood,
fiberglass, for example, and a suitable grinding surface 40 can be
used accordingly. Suitable grinding surfaces are readily available
in the art and can non-exclusively include grinding paper and sand
paper, for example. In general grinding surfaces include some type
of abrasive material, or grit, on the surface to be used to smooth
down a working surface. Suitable grinding surfaces non-exclusively
include coarse, medium, fine, very fine, extra fine, and super fine
sanding paper, for example. In certain embodiments, the grinding
surface 40 can include any suitable abrasive including ceramic,
aluminum oxide, alumina oxide, garnet, or silicon carbide, for
example. Any suitable grinding surface that can be used to smooth a
hard surface can be used with the teachings herein.
[0044] While the grinding surface can be attached to the disc's
underside 32 by any suitable means, in preferred embodiments, the
grinding surface 40 has a center aperture 42 configured to allow
the shaft 52 of the locking nut through. According to this
configuration, the grinding surface can be tightly secured against
the disc 30 through the use of the locking nut 50. In further
embodiments, the grinding surface includes multiple slots 44 around
the aperture 42, so the center of the grinding surfaced will be
held within the recess on the underside of the frustum 36. In still
further embodiments, the hubs and locking nuts described herein can
be used with any rotatable grinding, sanding, or cutting
attachment.
Locking Nut
[0045] In preferred embodiments, the locking nut 50 functions to
secure the grinding surface 40 and the disc 30 to the hub 20 and
the spindle 6 of the handheld grinder 2. In more specific
embodiments, the locking nut 50 can include a hollow, threaded
shaft 52 having an upward opening 58 connected to a base 53 having
a generally flat back 56. In more preferred embodiments, the
opening 58 does not continue to the back 56 of the locking nut 50.
In advantageous embodiments, the base 53 can be the shape of a
truncated cone, rising towards the shaft 52. In preferred
embodiments the angle of the base 53 is equivalent to the angle of
the frustum 36 of the disc 30, including 25 degrees for example. In
further embodiments, the base can rise at various other angles,
including the approximate range of 15-60 degrees (e.g., 15, 20, 30,
35, 40, 45, 50, and 55 degrees). In other embodiments, the base can
be flat, having a single height.
[0046] In preferred aspects, the shaft 52 is configured to attach
to the spindle 6. In more specific embodiments, it is preferred
that that the inside of the shaft 52 is threaded to screw onto the
spindle 6. While spindle length can vary according to different
models of angle grinders, the current standard in the industry for
many spindles is a thread count of 11 per inch and a 5/8 inch
diameter, including diameters of 1/4 inch and 3/8 inch, for
example. Accordingly, in preferred embodiments, the threaded shaft
is configured to attach to spindles with this standard thread count
and diameter, regardless of the spindle's length. In preferred
embodiments, the shaft is approximately 1 inch long and can
non-exclusively include 9, 10, 11, or 12 threads.
[0047] In further preferred embodiments, the back 56 of the locking
nut 50 is a planar, solid piece, without holes, to prevent dust or
debris from entering into the shaft 52, the hub 20, or the spindle
6. This particular embodiment of a "closed nut" is advantageous as
it substantially prevents dust build up in the spindle 6, which can
damage the spindle 6 and make removing grinding attachments
difficult. Preferred non-exclusive dimensions include a back 56
with a diameter of approximately 1 and 1/2 inches, a shaft 52 with
a 3/4 inch outer diameter, and a total height of the nut 50 (shaft
and base) at approximately 1.145 inches.
[0048] In other preferred embodiments the back 56 of the nut
includes means for unlocking the nut. In more preferred
embodiments, the means are notches 54 along the circumference of
the base 53. A wrench, or other suitable tool, can be used with
said means for unlocking the nut.
[0049] In more specific aspects of the teachings herein, the
locking nut 50 is configured to be secured with the spindle 6 such
that the back 56 of the locking nut 50 is secured within the
concave recess on the underside of the frustum 36, and within the
underside recess 23 on the hub 20. Under these preferred
configurations, the locking nut's back 56 does not protrude past
the plane of the grinding surface 40, or the planar underside 32 of
the disc 30. Accordingly, under this advantageous configuration,
the user can direct the entire grinding surface flat against a
working surface without grinding the back 56 of the locking nut
50.
[0050] While most preferred embodiments herein relate to grinding
assemblies for grinding or sanding, skilled artisans will also
recognize that the hub 20 and the locking nut 50 could also be used
with any suitable cutting attachment.
[0051] In advantageous embodiments, the locking nut 50 can be made
of any suitable metal, alloy, or plastic, but in preferred
embodiments, the locking nut 50 is made out of steel, aluminum, or
high-grade plastic. Metals and alloy based parts can be
manufactured according to any suitable technique in the art,
including but not limited to casting (e.g., investment or die
casting). Aluminum is a particularly desirable material to be used
with the locking nut 50 as it can dissipate heat evenly and
quickly.
[0052] Skilled artisans will recognize that the dimensions of the
locking nut 50 provided herein can readily be adapted to
accommodate different dimensions of spindles, discs, grinding
surfaces, and hubs.
[0053] The invention may be embodied in other specific forms
besides and beyond those described herein. The foregoing
embodiments are therefore to be considered in all respects
illustrative rather than limiting, and the scope of the invention
is defined and limited only by the appended claims and their
equivalents, rather than by the foregoing description.
* * * * *