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BACKGROUND OF THE INVENTION
I. Field of the Invention
This invention relates generally to apparatus for facilitating the repair
and refurbishment of damaged surfaces, and more particularly to a kit
including a plurality of sandpaper supporting devices which may readily be
adapted to conform to the characteristics of the work area to be finished
in an abrading operation, the device being either hand operated or machine
powered.
II. Discussion of the Prior Art:
In auto body repair or in the repair of fiberglass hulls on marine craft,
damaged areas are generally filled with a metal or plastic and, following
that, a rotary grinder may be used to grind down the filling material
until the original lines or contours are approximated. Following that, a
hand sanding operation is generally carried out in repeated steps and with
finer and finer grit abrasive paper until the surface being treated is
smooth, free of waves and ready for painting.
It has been found difficult to create an acceptable surface when a sheet of
sandpaper, either folded or unfolded, is held in the palm of the body
repairman's hand and rubbed back and forth across the area being
refinished. Any irregularities tend to show up as surface imperfections
when the painting has been completed. Irregular patterns often result from
hand-held abrasive paper as do waves and finger marks due to the
non-uniform pressure being applied. It is also known that sandpaper can be
mounted on a sanding block having a planar surface, but oftentimes such
blocks are too inflexible to permit the abrasive sheet to conform to the
contours of the surface being treated, especially if the surface is curved
rather than flat.
Not only should the sanding block be of a predetermined flexibility, but,
moreover, blocks of varying width and length dimensions are needed if the
labor involved is to be reduced. That is to say, where large surfaces,
such as marine hulls, automotive side panels, trunk lids and hoods are
involved, a longer and wider sandpaper supporting block may be employed
such that larger areas can be abraded in a few passes of the hand sanding
apparatus, thus saving on labor costs. Shorter blocks may generally become
useful where sharper corners or surface transitions are encountered.
The 3M Company of St. Paul, Minn., is a major supplier of abrasive papers
to automobile body shops and marine repair facilities. These sandpapers
come in varying grits and generally are dispensed from a roll, the rolls
coming in two different width dimensions. The non-abrasive surface of the
papers are generally coated with an adhesive, facilitating the securement
of the paper to a sanding block. When it becomes necessary to change the
paper to obtain a different abrasive grit, it has been the practice in the
past to peel off the original length of abrasive paper from the sanding
block and then replace it with a new piece having the desired grit. When
it is considered that the first piece being replaced may still have from
50% to 90% of useful life and that the environment of a body shop is
extremely dusty and dirty, the partially used piece of sandpaper often
becomes totally unusable when the adhesive backing becomes coated with
dust and dirt so that it cannot be reapplied to the sanding block at a
later time. Thus, while it would be advantageous to be able to reuse
sandpapers whose abrasive qualities have not been totally used up, this
has heretofore been impossible because once the partially used piece of
sandpaper has been stripped from its sanding block and allowed to sit in a
dusty environment, its adhesive backing loses its tackiness.
Prior art sandpaper supporting blocks also incorporate a variety of styles
of handles for facilitating their gripping and manipulation of the sanding
blocks during use. For example, for shorter sanding blocks, only a single
handle member may be required. Longer sanding blocks, e.g., those about
21/2 feet in length, will generally have two handles spaced along the
length dimension of the sanding block. Then, too, the shape of the handle,
e.g., its height or contour may vary depending upon the surface or
surfaces to be abraded and the desires of the user. With prior art sanding
arrangements, it has been necessary to provide a large multiplicity of
sanding blocks, given the many permutations and combinations of block
length, block width, handle location and handle geometry. This
necessitates an inordinately high number of sanding blocks, each equipped
with its own handle (or set of handles) to accommodate the variety of
contours that may be encountered during a body finishing operation.
SUMMARY OF THE INVENTION
In accordance with the present invention, all of the foregoing drawbacks of
prior art sandpaper supporting devices for surface refinishing are
obviated In particular, the sandpaper medium can be readily removed and
replaced with one of a different grit without wasting a partially worn
segment of sandpaper. Moreover, different sandpaper holding devices are
provided with replaceable handles of a limited number of styles, allowing
the operator to select the sanding block size and handle style to suit his
immediate needs.
The present invention provides a kit in which a plurality of plate members
of differing width and length dimensions are provided as are a plurality
of handle members of differing size and shape configuration. Means are
provided for rapidly securing and removing the handle members onto or from
any of the selected plate members with the securing means allowing the
handles to be located at any of a number of desired locations along the
length of t hat plate member.
The adhesive backed sandpaper is arranged to be attached to a base which,
in turn, removably attaches to the plate member bearing the handles. The
base can be stripped away from the plate member carrying the handles and a
new base member having a sandpaper of a differing grit can then be
substituted. Thus, the adhesive backing on the sandpaper is not exposed to
dirt and contamination when a paper of a different grit is substituted.
This allows an already used, but not yet worn out, abrasive paper to be
reused, thus reducing cost.
OBJECTS
It is accordingly a principal object of the present invention to provide a
new and improved sanding system for facilitating the repair and
refurbishment of damaged surfaces.
Another object of the invention is to provide, as a kit, a plurality of
sandpaper supporting devices, which may readily be adapted to conform to
the characteristics of the work area to be finished in an abrading
operation, and having means for releasibly attaching one or more handle
members to the supporting device.
Yet another object of the invention is to provide, as a kit, a plurality of
sandpaper supporting devices in which the abrasive medium can be removed
from the supporting device without exposing the adhesive coating on the
sandpaper to contamination.
The foregoing objects and advantages of the invention will become apparent
to those skilled in the art from the following detailed description of a
preferred embodiment, especially when considered in conjunction with the
accompanying drawings in which like numerals in the several views refer to
corresponding parts.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the hand sanding apparatus of the present
invention;
FIG. 2 is a cross-sectional view of the apparatus of FIG. 1 taken along the
line 2--2;
FIG. 3 is a cross-sectional view taken along the line 3--3 in FIG. 1;
FIG. 4ak and FIG. 4b are cross-sectional views taken along the line 4--4 in
FIG. 3 with the hand grip locking latch in its two operating positions;
FIG. 5 is a side view of the airfile adapter usable with the hand sanding
apparatus of FIG. 1; and
FIG. 6a and FIG. 6b are views taken along the line 6--6 in FIG. 5 with the
slide plate in the locked and unlocked dispositions, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1, there is indicated generally by numeral 10 one
member of a hand sanding kit useful in the repair of damage to automobiles
and fiberglass boat hulls. The general purpose of the device of FIG. 1 is
to support, i.e., back-up, a sheet of abrasive material such as sandpaper.
The members of the kit would be of varying length, but otherwise would be
substantially identical. Hence, it should only be necessary to describe
the constructional features of one member of the kit for the reader to
have an overall comprehension of the invention.
The device 10 comprises a first, generally flat, somewhat rigid plate
member 12 of a predetermined length and width dimension and exhibiting a
limited degree of flexibility in a direction transverse to the length
dimension of the tool. By way of example, and not as a limitation, the
plate member may be 2.75 inches in width and, depending upon the
characteristics of the workpiece to be abraded, may be of a length
anywhere in the range of from about 6 inches to 36 inches. Again, without
limitation, the plate member 12 may be fabricated from sheet metal such as
aluminum or cold rolled steel, but I have found that a polycarbonate
plastic sheet material, such as that sold under the trademark LEXAN.RTM.,
possesses the characteristics of being easy to work with, relatively low
in cost, and being very rugged and able to hold up over a substantial
period of time.
Integrally molded with the plate member 12 and extending parallel to the
length dimension thereof are a pair of rails 14-14. Alternatively, the
rails 14 may be thermally or adhesively bonded to the base plate 12 and
function to provide a desired degree of flexibility to the assembly so
that a certain degree of manual forces required to bend or otherwise
distort the tool so as to conform to the surface of the workpiece to be
abraded.
Also secured to the upper exposed major surface of the plate member 12 are
pairs of transversely extending ribs identified in FIG. 1 by the numerals
16 through 22. As shown in the cross-sectional view of FIG. 3, the ribs 16
through 19 are under cut to allow a handle means indicated generally by
numeral 24 to be releasibly attached to the upper surface of the plate
member 12 at predetermined discrete locations along the length dimension
thereof. For example, and as indicated by the dotted lines, the handle
means 24 can be dropped vertically downward as shown in FIG. 3 and latched
to the base member by inserting the rearwardly projecting tab 26 on the
handle means into the undercut portion of the rib 19 at which point a cam
actuated latch yet to be described can be deployed to fit within the
undercut portion of the rib 17. The rib 18 will then fall within a
transverse notch 28 formed in the base portion 30 of the handle means 24.
Alternatively, the tab 26 can be selectively inserted into the undercut
portion of the rib 18 with rib 17 fitting in the slot 28 and the cam
actuated tab deployed in the cutout portion of the rib 16.
Depending upon the length of the tool, it may have only one such handle
means as at 24. However, for base plates of a predetermined greater
length, it is found convenient to provide a second handle means as at 32
which itself is releasibly attachable to the upper surface of the base
plate 12 in the same fashion that the handle means 24 is secured. Thus,
the handle means 32 can be selectively deployed at a desired position
along the length of the tool so as to provide a desired degree of control
to the tool when using both hands to manipulate it much like a carpenter's
plane.
As best seen in the cross-sectional views of FIGS. 2 and 3, mating strips
34 and 36 of Velcro.RTM. hook and loop material are adhered to a second
major surface of the plate member 12, i.e., its under surface, and to the
upper surface of a further flexible planar sheet 38. The sheet 38 may be
fabricated from an appropriate material including metals or plastics, but
LEXAN polycarbonate plastic is again preferred for the reasons already
indicated. Adhered to the under side of the sheet 38 is a layer 40 of
resilient pad material such as knobby NEOPRENE to which an adhesive coated
sheet of sandpaper (not shown) can be adhered. Because of the use of the
Velcro hook and loop material, the plate 38, pad 40 and the sandpaper
adhered to it can be removed as a unit from the plate member 12 and
replaced with a similar assembly only containing an abrasive sheet having
a different grit. Thus, as the need demands, the type of sandpaper can be
substituted or replaced without having to throw the first sheet away
before it has been completely used. As shown in FIG. 3, the views of FIGS.
4a and 4b illustrate the underside of the hand grip means 24. The base or
pedestal portion 30 of the handle means 24 has a rivet or pin 42 as an
axis passing through it and through a latch plate 44 to which a thumb
lever 46 is attached. By manipulating the thumb lever 46, a portion of the
latch plate 44 can be either made to project outwardly from the end 48 of
the pedestal 30 or be retracted relative to it. Thus, in installing the
handle 24 onto the base plate 12, the lever 46 would be positioned so that
the latch plate is retracted. Then, the user would deploy the tab portion
26 of the pedestal into the undercut portion of one of the ribs with the
sides of the pedestal being straddled by the longitudinal rails 14. Next,
by rotating the latch lever 46, the nose portion of the latch plate 44 can
be made to project into a mating undercut portion of a rib to firmly lock
the handle means to the plate member 12.
It is also contemplated that the sanding apparatus of FIG. 1 can also be
utilized with a so-called airfile. As those familiar with tools used in
the automobile and marine repair business appreciate, an airfile is a
device that can be connected to a source of compressed air and used to
rapidly reciprocate a backup member supporting a sheet of abrasive
material. This, of course, facilitates the sanding operation in that the
operator need merely guide the reciprocating tool over the surface to be
treated and need not himself provide the back and forth motion to achieve
the abrading result. The airfile apparatus, however, is completely rigid
and generally would not conform to curved surfaces. In accordance with the
present invention, an adapter shown in FIGS. 5, 6a and 6b can be used in
place of the handle means 24 and 32 of FIG. 1 to join an airfile to the
base plate 12 in such a fashion that flexure of the base plate 12 can
still take place.
With reference to FIG. 5, the airfile adapter member is indicated generally
by numeral 50 and is seen to include a planar base 52 which, as indicated
below, is releasibly attachable to the upper exposed surface of the plate
member 12 in a somewhat similar fashion to the manner in which the handle
members 24 attach. The adapter 50 also includes first and second side
walls 54 and 56 projecting perpendicularly to the planar base 52. The side
walls have a sloping contour and go from a minimum height at the opposed
ends of the side walls to a maximum height approximately midway along the
length dimension of the side walls. A channel-shaped member 58 having a
planar airfile attachment surface 60 is pivotally supported between the
side walls 54 and 56 for limited rotation about an axis provided by a pin
62 disposed approximately at the maximum height location of the side walls
54 and 56 and passing through aligned apertures. Thus, the surface 60 can
rock, to a limited degree, in the clockwise and counterclockwise direction
when viewed in FIG. 5.
FIGS. 6a and 6b illustrate a preferred way of securing the airfile adapter
50 to the upper surface of the plate member 12. As can be seen in this
Figure, longitudinal grooves are cut in the planar base portion 52 to
permit a rectangular side plate 64 to be fitted therein for longitudinal,
reciprocal movement. The side plate 64 includes a perpendicularly
extending pin 66 which cooperates with a horseshoe-shaped slot 68 formed
in the latch plate 44. Thus, the pin 66 and the horseshoe-shaped slot 68
comprise a cam and follower arrangement so that when the latch plate 44 is
deployed as indicated in FIG. 6a, the end 70 of the slide plate 64 extends
outwardly beyond the side walls 54 and 56 of the adapter 50 and can thus
be positioned within the undercut portion of a rib 16-22 on the base
member 12. When the end 70 extends outwardly as indicated in FIG. 6a, the
nose portion of the cam 44 also projects outwardly from the forward end of
the adapter and it, too, would then fit within an undercut portion of a
mating transverse rib to latch the adapter in place.
With reference to FIG. 6b, then, when the latch plate 44 is rotated so that
its nose portion no longer projects outwardly relative to the forward end
of the adapter, the end 70 of the slide plate is also retracted, allowing
the adapter to be lifted free of the base member.
The threaded stud 72 extending upwardly from the airfile attachment surface
60 is intended to pass through a mating bore on the airfile so that a nut
can be used to secure the airfile to the adapter. In a typical situation,
two such adapters would be used with a base plate assembly and the airfile
would span the distance between the studs 72 on the pair of adapters. By
providing the ability for the airfile attachment surface to pivot relative
to the side walls 54 and 56 thereof, a limited degree of flexure of the
assembly supporting the abrasive sheet can take place even though the
airfile attachment itself is inflexible.
Thus it can be seen that there is provided by this invention a kit
including a plurality of abrasive paper backup members of uniform width
but varying lengths and constructed so as to be usable with removal
handles which can be readily joined to any one member of the kit when that
member is selected for use. Each of the members includes a removable base
which allows abrasive sheets of differing grits to be readily attached to
the sanding apparatus as called for by the particular application but
without leaving the replaced abrasive sheet in a dust ladened environment
and thus rendered unsuitable for future use.
This invention has been described herein in considerable detail in order to
comply with the Patent Statutes and to provide those skilled in the art
with the information needed to apply the novel principles and to construct
and use such specialized components as are required. However, it is to be
understood that the invention can be carried out by specifically different
equipment and devices, and that various modifications, both as to the
equipment details and operating procedures, can be accomplished without
departing from the scope of the invention itself. For example, it will be
recognized that there are alternative ways of removably fastening handle
members to the flexible plates and bases other than the cam and latch
arrangement specifically illustrated herein. One such variation is that
Velcro hook and loop material may be used to releasibly bond the handles
to the sanding plates.
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