U.S. patent application number 10/939174 was filed with the patent office on 2006-03-16 for buffing pad with graded flexibility and replaceable working face.
Invention is credited to Scott S. McLain.
Application Number | 20060053576 10/939174 |
Document ID | / |
Family ID | 35115690 |
Filed Date | 2006-03-16 |
United States Patent
Application |
20060053576 |
Kind Code |
A1 |
McLain; Scott S. |
March 16, 2006 |
Buffing pad with graded flexibility and replaceable working
face
Abstract
A rotary buffing and finishing pad assembly includes a polymeric
foam cushioning layer that has a graded compression load deflection
which is interposed between a backing plate and a relatively thin
performance layer that is removably attached to the foam cushioning
layer. Alternate constructions for providing a graded cushioning
effect are also disclosed.
Inventors: |
McLain; Scott S.;
(Mukwonago, WI) |
Correspondence
Address: |
Joseph J. Jochman;ANDRUS, SCEALES, STARKE & SAWALL, LLP
Suite 1100
100 East Wisconsin Avenue
Milwaukee
WI
53202-4178
US
|
Family ID: |
35115690 |
Appl. No.: |
10/939174 |
Filed: |
September 10, 2004 |
Current U.S.
Class: |
15/230 |
Current CPC
Class: |
B24D 13/147 20130101;
B24D 9/085 20130101 |
Class at
Publication: |
015/230 |
International
Class: |
A47L 25/00 20060101
A47L025/00 |
Claims
1. A rotary surface buffing and finishing apparatus of the type
providing flexible cushioned support for a high performance surface
contacting face, said apparatus comprising a polymeric foam
cushioning layer having a graded compression load deflection that
decreases from a rear face to a front face and providing the
primary cushioned support, and a relatively thin performance layer
providing the entire high performance surface contact, said
performance layer removably attached to the foam cushioning
layer.
2. The apparatus as set forth in claim 1 including a backing plate
attached to the rear face of the foam cushioning layer and
supporting the foam cushioning layer.
3. The apparatus as set forth in claim 2 wherein the backing plate
has a circular front face and is rotatable on a center axis
perpendicular to the front face; the foam cushioning layer being of
circular shape and having one-half of a hook and loop fastener
attached to its front face; and; the performance layer having a
rear face carrying the other half of the hook and loop fastener and
having an operating face selected to provide a surface contact
optimized for a given buffing or finishing operation.
4. The apparatus as set forth in claim 3 wherein the fastener
halves are heat laminated to the respective faces of the foam
cushioning layer and the performance layer.
5. The apparatus as set forth in claim 3 wherein the fastener
halves are glued to the respective faces of the foam cushioning
layer and the performance layer.
6. The apparatus as set forth in claim 3 wherein at least one of
the interface between the fastener halves and the respective faces
of the foam cushioning layer and the performance layer is provided
with a barrier material to prevent migration of liquid and compound
from the performance layer to the foam cushioning layer.
7. The apparatus as set forth in claim 6 wherein the barrier layer
is between the rear face of the performance layer and the other
half of the fastener.
8. The apparatus as set forth in claim 1 wherein the performance
layer is selected from the group consisting of open cell
polyurethane foam, non-woven fibers, tufted wool, knitted wool,
polymeric microfibers, and combinations thereof.
9. The apparatus as set forth in claim 3 wherein the front face of
the foam cushioning layer is generally planar and terminates in an
outer edge that is upwardly rounded, a portion of the one-half of
the fastener is positioned on the rounded outer edge, and the other
half of the fastener on the performance layer is dimensioned to
extend over said outer edge to engage the portion of said one-half
of the fastener and impart a cup shape to the performance
layer.
10. A rotary surface buffing and finishing apparatus comprising: a
backing plate having a circular front face and a back face having a
center attachment hub for driving rotation on an axis perpendicular
to the front face; an intermediate foam cushioning layer having a
rear face attached to the front face of the backing plate and a
front face carrying one-half of a hook and loop fastening system,
said foam cushioning layer having a graded compression load
deflection that decrease from the rear face to the front face ;
and, a performance layer of buffing and finishing material having a
rear face carrying the other half of the hook and loop fastening
system for removable attachment to the front face of the cushioning
layer, and a front buffing and finishing face selected to provide a
desired surface finish only when attached to said cushioning
layer.
11. The apparatus as set forth in claim 10 wherein the cushioning
layer is molded to the backing plate.
12. The apparatus as set forth in claim 11 wherein the backing
plate comprises a molded nylon and the cushioning layer comprises a
molded urethane.
13. A surface buffing and finishing apparatus of the type providing
flexible cushioned support for a high performance surface
contacting face, said apparatus comprising: a polymeric foam
cushioning layer having a rear face and a front face and providing
the primary cushioned support; a relatively thin performance layer
providing the entire high performance surface contact, said
performance layer removably attached to the foam cushioning layer;
a backing plate attached to the rear face of the foam cushioning
layer and supporting the foam cushioning layer, the backing plate
having a flexible peripheral edge; the foam cushioning layer being
of circular shape and having one-half of a hook and loop fastener
attached to its front face; the performance layer having a rear
face carrying the other half of the hook and loop fastener; the
front face of the foam cushioning layer terminating in an outer
edge that is upwardly rounded, a portion of the one-half of the
fastener being positioned on the rounded outer edge, and the other
half of the fastener on the performance layer is dimensioned to
extend over said outer edge to engage the portion of said one-half
of the fastener and impart a cup shape to the performance
layer.
14. The apparatus as set forth in claim 13 wherein the interface
between said other fastener half and the performance layer is
provided with a barrier layer to prevent migration of liquid and
compound from the performance layer to said fasteners and the foam
cushioning layer.
15. The apparatus as set forth in claim 13 wherein the hardness of
the backing plate and the foam cushioning layer are chosen to
provide a graded flexibility for a selected finishing operation.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention pertains to rotary or dual action
buffing and finishing pads made of polymeric foam material and,
more particularly, to a composite pad construction that includes an
intermediate cushioning layer having a graded compression load
deflection and a relatively much thinner performance layer that
provides the necessary surface finishing function, but can be
easily and inexpensively replaced when worn or damaged.
[0002] Polymeric foam buffing pads have been used for many years to
perform a variety of buffing and finishing functions for painted
and clear coat surfaces in the automobile and other industries. As
the construction of foam buffing pads evolved, it became apparent
that open cell polyurethane foam materials provided the best
performance. Currently, reticulated open cell polyurethane foams
are the most desirable polymeric foams for buffing and finishing
functions. However, reticulated open cell polyurethane foam
materials are also the most expensive. This material provides a
combination of surface finishing performance and cushioning effect
that has made reticulated open cell polyurethane foams the most
desirable polymeric foam in the buffing and finishing industry.
[0003] Typical polyurethane foam pads range in size from less than
6 inches to greater than 8 inches (about 150-200 mm) in diameter,
and 1.25 to 1.75 inches (about 30-45 mm) in thickness. The
thickness of the material, in particular, is necessary to provide
proper cushioning for the desired finishing operation. However,
only a small part of the surface contacting face of the pad is
actively used for the desired buffing or finishing operation.
SUMMARY OF THE INVENTION
[0004] In accordance with the present invention, most of the
cushioned support for a polyurethane foam buffing and finishing pad
is provided by polymeric foam material that does not directly
contact the surface to be finished, is made of less expensive
material, and may be provided with a graded density, graded
flexibility, or graded levels of compression load deflection. This
composite pad construction provides performance that is identical
to a monolithic reticulated open cell polyurethane foam pad, but at
considerably less cost. A relatively thin performance layer, made
of the more expensive polyurethane foam, is removably attached to
the less expensive foam cushioning layer.
[0005] Thus, a rotary buffing and finishing apparatus of the type
that provides flexible cushioned support for a high performance
contacting face, includes a polymeric foam cushioning layer that
has a graded compression load deflection that decreases from a rear
face to a front face and provides the primary cushioned support. A
relatively thin performance layer provides the entire high
performance surface contact and is removably attached to the foam
cushioning layer.
[0006] The apparatus of the present invention preferably includes a
backing plate that is attached to the rear face of the foam
cushioning layer and supports the foam layer. The backing plate and
the cushioning layer may comprise an integrally molded urethane
material that provides the graded compression load deflection that
varies from a relatively hard but somewhat flexible backing plate
to a much softer front face for attachment to the performance
layer.
[0007] In a preferred embodiment, the backing plate has a circular
front face that is rotatable on a center hub with an axis
perpendicular to the front face, the foam cushioning layer is also
of a circular shape and has one-half of a hook and loop fastener
attached to its front face. A performance layer, which is also
circular in shape, has a rear face that carries the other half of
the hook and loop fastener and a front operating face that is
selected to provide a surface contact optimized for a given buffing
or finishing operation. The performance layer may be selected from
the group consisting of reticulated open cell polyurethane foam,
non-woven fibers, tufted wool, knitted wool, polymer microfibers,
and combinations thereof.
[0008] The hook and loop fastener halves may be heat laminated or
glued to the respective faces of the foam cushioning layer and the
performance layer. Either one of the interfaces between the hook
and loop fastener halves and the faces of the cushioning layer or
performance layer, preferably the latter, may be provided with a
barrier material to prevent migration of liquid and compound from
the performance layer to the foam cushioning layer.
[0009] In one embodiment of the apparatus, the front face of the
foam cushioning layer is generally planar and terminates in an
outer edge that is upwardly rounded. A portion of the half of the
hook and loop fastener is positioned on the rounded outer edge and
the other half of the fastener on the performance layer is
dimensioned to wrap around the outer edge to engage the portion of
the first half of the fastener. This imparts a cup shape to the
performance layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a rotary buffing and
finishing pad assembly of the present invention mounted on the
drive shaft of a power driving machine.
[0011] FIG. 2 is a top plan view of the assembly shown in FIG.
1.
[0012] FIG. 3 is an exploded view of the assembly shown in FIGS. 1
and 2.
[0013] FIG. 4 is a bottom plan view of the cushioning layer of the
assembly taken on line 4-4 of FIG. 3.
[0014] FIG. 5 is an assembled elevation view of the apparatus of
FIG. 3.
[0015] FIG. 6 is a sectional detail of FIG. 5.
[0016] FIG. 7 is an elevation view of an alternate embodiment of
the invention, partly in section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] In FIGS. 1-4, a rotary buffing and finishing tool assembly
10 includes a one-piece hub 11 and backing plate 12, carrying an
intermediate cushioning layer 16 to which is releasably attached a
relatively thin circular performance layer 13 that provides surface
contact for the buffing or finishing operation. The hub 11 is
preferably made of a hard plastic, such as a molded nylon, and
includes a central nut 14 insert molded into the hub to provide
connection to a power driving tool. The integral backing plate 12
extends radially outwardly from the hub 11 and has a generally
conical front face 15 that ends in a flattened outer edge 19. The
cushioning layer 16, preferably of a polymeric foam material, is
attached to the hub and the front face 15 of the backing plate and
also extends upwardly around the peripheral edge 19 of the backing
plate 12 to form a rounded outer edge 17. The front face 18 of the
cushioning layer 16 is generally flat and has attached thereto a
circular fastener layer 20 comprising one-half of a hook and loop
fastener (typically the hook half). In the embodiment shown, the
rounded outer edge 17 of the cushioning layer 16 has attached
thereto an outwardly facing thin fastener strip 21, also comprising
the same hook and loop fastener material as the circular fastener
layer 20.
[0018] The performance layer 13, comprising a reticulated open cell
polyurethane foam in the example shown, is cut in the shape of a
thin circular disc. The thickness of the performance layer 13 may
be about 3/8 inch (about 10 mm), but the thickness may vary
considerably, particularly if the performance layer is selected
from an entirely different material as will be discussed
hereinafter. The rear face 22 of the performance layer 13 has
attached thereto a circular fastener layer 23 comprising the other
half of the hook and loop fastener (typically the loop half), i.e.
complimentary to the circular fastener layer 20 on the front face
of the cushioning layer 16. In this embodiment, the diameter of the
performance layer 13 is larger than the diameter of the cushioning
layer 16. The outer edge of the polyurethane foam performance layer
13 is turned upward and wrapped around the rounded outer edge 17 of
the cushioning layer. The edge of the circular fastener layer 23 on
the rear face of the performance layer 13 engages the fastener
strip 21 on the rounded outer edge 17 of the cushioning layer to
hold the performance layer in a cupped shape, as shown.
[0019] The cushioning layer 16, in the embodiment shown, is molded
directly to the hub and backing plate 11, 12. In accordance with an
important aspect of the present invention, the cushioning layer 16
is formed with a graded compression load deflection that decreases
from a rear face 24 in contact with the front face 15 of the
backing plate to the front face 18 where it is attached to the rear
face of the performance layer 13. The term "compression load
deflection" is used in the polymeric foam industry as a measure of
the compressibility of a foam material. In one standard test, the
compression load deflection (CLD) is measured at 40% compression of
a test piece. For one fully reticulated open cell polyurethane
foam, a CLD of 0.65 to 1.25 psi (about 4.5 to 8.6 kPa) is typical.
The average density of this foam is 2.4 lbs./ft..sup.3 (38.5
kg/m.sup.3). However, in accordance with the present invention, the
cushioning layer 16 is preferably made of a foam material that is
less expensive than the material used for the performance layer.
The cushioning layer 16 is molded such that its compression load
deflection (or equivalent property) decreases from the rear face 24
(adjacent the backing plate 12) to the front face 18 (where it is
attached to the rear face of the performance layer 13). The
polymeric foam from which the cushioning layer 16 is formed
provides a cushioning effect that is virtually the same as it would
be if the combined cushioning layer and performance layer were made
of a single monolithic piece of high performance reticulated open
cell polyurethane foam. Foam materials, such as molded
polyurethane, that are far less expensive than the high performance
foam layer 13, may be used. The backing plate 12 may also be made
of a material which, though significantly harder than the foam
cushioning layer 16, retains a flexibility that adds to the
cushioning effect. A satisfactory result may be obtained with a
construction utilizing a flexible backing plate 12 and a cushioning
layer 16 that comprises a material of uniform hardness across its
full depth. In general, whether the graded cushioning effect
provided by the components of the subject invention is measured by
compression load deflection, durometer or density, the key is that
such property decreases from the backing plate to the front face 18
of the cushioning layer 16.
[0020] In the embodiment shown and referring particularly to FIGS.
3 and 6, the graded CLD (or graded durometer) of the cushioning
layer 16 is provided by joining two separate layers of polyurethane
foam having different CLDs (and densities). A first layer 33 of
higher CLD polyurethane foam is molded to the hub and backing plate
11, 12 and second layer 34 of a lower CLD polyurethane foam is
molded directly to the first layer 33. In one example of a pad of
the type shown in FIG. 3, molded polyurethane foam layers 33 and 34
having respective durometers (Shore A) of about 30 to 32 and 10 to
15 were used to form a cushioning layer 16 having a diameter of 4.5
inches (about 115 mm). The second layer 34 had a uniform thickness
of about 1/2 inch (about 13 mm), and the thickness of the upper
layer 33, though having a variable cross-section, also averaged
about 1/2 inch (13 mm) in thickness. The first layer 33 is also
molded to extend around the flattened outer edge 19 of the backing
plate, as shown.
[0021] When the performance layer 13 becomes excessively worn or
torn, or becomes plugged with buffing or finishing compound, the
thin performance layer 13 may simply be peeled away from the
cushioning layer 16 and replaced. This results in a considerable
saving where a monolithic high performance foam buffing pad, having
a typical thickness in the range of 1.25 to 1.5 inches (about 32 to
40 mm), would otherwise have to be discarded.
[0022] Each of the circular fastener layers 20 and 23 (as well as
the fastener strip 21) normally includes an adhesive layer that is
used to adhere the fastener layers to the surfaces being joined. In
the assembly of the present invention, however, the adhesive layers
are preferably eliminated and the hook and loop fastening pieces
are adhered directly to the respective foam cushioning layer and
foam performance layer by flame lamination or other suitable
heating or gluing process.
[0023] It is also desirable, in certain applications, to provide
the interface between one of the fastener layers 20 or 23 and the
respective foam layer 16 or 13, preferably the performance layer 13
and fastener layer 33, with a layer 35 of an impervious barrier
material. This prevents migration of finishing liquids or compounds
from the performance layer 13 into the foam cushioning layers 16. A
layer of barrier material would thus protect the foam cushioning
layer, and when applied to the rear face 22 of the performance
layer 13, will also protect the fastener layers 20 and 23 from
contamination and plugging.
[0024] The unitary hub and backing plate 11, 12 can also be molded
separately and the cushioning layer 16 also formed separately and
attached to the front face 15 of the backing plate 12. Attachment
of the foam cushioning layer to the backing plate can be permanent,
as by gluing or heat bonding, or demountable as with a hook and
loop fastening system.
[0025] In FIG. 7, there is shown an alternate embodiment of a
replaceable performance layer 25 that is also mounted on a modified
backing plate 26 via an intermediate cushioning layer 27. As in the
preferred embodiment, one-half of a hook and loop fastener 29 is
attached to the rear face 28 of the performance layer 25 and the
other half 36 to the front face 30 of the cushioning layer 27
permitting easy replacement of the performance layer. The
peripheral edge of the cushioning layer 27 is provided with a
frustoconical edge surface 32. The performance layer 25 may be the
same size, shape and material as in the previously described
embodiment. This arrangement provides a performance layer with a
relatively square peripheral edge for certain buffing and finishing
operations on surfaces having an abrupt change in contour. The
cushioning layer 27 is made with the same graded compression load
deflection as the cushioning layer 16 of the previously described
embodiment.
[0026] As may be seen best in FIGS. 6 and 7, the backing plates 12
and 26 have relatively thin sections from the flattened outer edge
19 all the way to their juncture with the hub 11. Although the
molded plastic hub and backing plate is relatively hard, as
compared to the various foam materials, the thin section of the
backing plate adds an additional measure of flexibility to the
buffing and finishing assembly. It is believed that this additional
flexibility enhances the overall performance and permits the use of
heavier, more dense and higher CLD foam materials in the cushioning
layers 16 and 27, as compared to a single monolithic block of
reticulated open cell polyurethane foam such as comprises the
performance layers 16 and 25.
[0027] In certain applications, the flexible backing plate 12 may
be used with a cushioning layer of monolithic construction not
having a graded density or CLD. The flexible backing plate operates
to replace the more dense and higher CLD layer 33 of the preferred
embodiment. The backing arrangement thus provides a graded
flexibility that serves to simulate the graded CLD of the preferred
embodiments.
[0028] The thin performance layers of reticulated open cell
polyurethane foam that characterize the previously described
embodiments may be replaced with performance layers of other
materials using the same cushioning layer and back-up plate
arrangements previously described. Thus, performance layers of
tufted wool, knitted wool, non-woven fibers, polymer microfibers,
and combinations thereof, all in relatively thin sections, may be
used. As with the previously described performance layer
embodiments, these alternate performance layers should also be
provided with a layer of barrier material to prevent contamination
of the fastener system and the cushioning layer.
* * * * *