Abrasive sheets

An abrasive sheet such as sandpaper has standard dimensions to fit 1/3, 1/2 or 1/4 sheet sanding machines having dust extraction facilities. The sheet has perforated delineated separable or frangible areas adapted to be removed by the user to form one pattern of an array of patterns of holes in the sheet to correspond with the holes in the sole plate of the particular model of abrading or sanding machine which the user is employing. This enables one sheet to be used with several different models. Such an arrangement also ensures that the unperforated portions of the sole plate of the abrading machine are covered by unseparated frangible areas of the abrasive sheet. This is accomplished by defining the frangible areas using circular configurations of perforations. A method for using the abrasive sheet includes the steps of separating the appropriate frangible areas from the abrasive sheet and connecting the sheet to the sole plate so that the pattern of separated frangible areas matches the pattern of dust extraction holes in the sole plate of a particular abrading machine.

BACKGROUND OF THE INVENTION 
This invention relates to abrasive sheets for use in power sanding machines 
having vacuum dust extraction. Sanding machines, by their very nature, 
generate considerable quantities of dust, and many presently available 
models provide vacuum extraction facilities which minimize the spread of 
dust. Orbital sanding machines achieve this by sucking the dust through 
the sanding machine as it is being generated. For this purpose the sole 
plate of the sanding machine is provided with numerous holes through which 
the dust can be extracted. The present invention relates particularly to 
machines which employ this method of dust extraction. Needless to say, the 
sheets of abrasive used by machines of this type need to have holes which 
correspond with the holes in the sole plate. Since machines made by 
different manufacturers tend to have different patterns of holes in their 
respective sole plates, each sanding machine requires its own 
specially-adapted abrasive sheets having the appropriate matching holes. 
It has been suggested to provide sheets which have holes pre-punched in 
them to match all configurations of holes presented by the various 
manufacturers' sole plates. However, this is not a solution because the 
holes in the abrasive sheet which do not coincide with holes in the sole 
plate of any given machine will expose portions of the base of that 
machine's sole plate. Since the base of the sole plate is normally a soft 
rubber-like material (for example neoprene rubber) to cushion the abrasive 
sheet against the surface being sanded, it is not protected against the 
heat which may be generated if it were to be allowed to make direct 
contact with the worksurface. 
Thus it is an object of the present invention to provide abrasive sheets 
which can be employed on a variety of different machines while allowing 
the dust extraction facility to be employed but without suffering from the 
aforementioned problem. 
SUMMARY OF THE INVENTION 
In accordance with the present invention there is provided a sheet of 
abrasive material, such as sandpaper, of standard dimensions for use on a 
variety of different machines, said sheet having a plurality of separable 
or frangible areas delineated by perforations enabling selected ones of 
said areas to be separated from the sheet to form holes in said sheet 
according to one desired pattern of an array of patterns of areas suitable 
for a particular abrading or sanding machine to which said sheet is to be 
fitted. 
Of course, where the machine in question is not of the type incorporating 
dust extraction, or if for any reason the user does not wish to employ the 
vacuum dust extraction facility of his/her machine, then none of said 
areas is separated from the sheet. In that event the sheet performs as an 
ordinary sheet of abrasive. 
On the other hand, the perforated areas are provided so that they may be 
pushed out by the user according to the pattern of holes formed on his/her 
particular machine. 
Preferably the sheet is provided with instructions on one surface, for 
example, its front surface, indicating to the user which areas should be 
removed to suit particular machines. 
The term "of standard dimensions" as used herein refers, for example, to 
the standard sheet sizes of sandpaper in the United Kingdom as set down in 
BS871. Several sanding machines are adapted, on the whole, to employ 
sheets of abrasive which conform to these standards. However, it should be 
appreciated that the scope of the present invention is not limited by 
particular standards as such, but rather by the sizes of sheets generally 
or widely adopted in a particular market at any given time. Also it is not 
intended to limit the application of the present invention geographically; 
it will have utility in any country in which abrading machines of the type 
discussed above are used. 
Also in accordance with the present invention is a method for using the 
abrasive sheet including the steps of separating the appropriate frangible 
areas from the abrasive sheet and connecting the sheet to the sole plate 
so that the pattern of separated frangible areas matches the pattern of 
dust extraction holes in the sole plate of a particular abrasive machine, 
then using the machine to abrade a workpiece.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1, the back of a sheet 1 of sandpaper is shown. The sheet is 
provided with a plurality of perforated delineated or punch-out areas 2, 
2' forming an array of patterns of areas such that any of such areas may 
be pushed or punched out to form said pattern of holes in the paper. The 
punch-out areas 2, 2' need not be circles. Depending upon the sanding 
machines, areas 2,2' may be oval, rectangular, or any geometry necessary 
to match the holes in the various sole plates contemplated to be in use in 
a given market. 
In the first embodiment, Sheet 1 is sized to fit a particular range of 
orbital sanding machines, that is to say, those which employ 1/3-sheet 
sizes according to British Standard 871. 1/2-sheet or 1/4-sheet sanding 
machines are also available. The array of patterns, and indeed sizes, of 
said punch-out areas 2, 2' are arranged to correspond with a plurality of 
different sanding machines within the size range for that sheet. 
Thus the pattern of punch-out areas 2, for the 1/3-sheet machine, 
corresponds to the size and arrangement of holes in the sole plate of an 
orbital sander provided with dust extraction facilities marketed, for 
example, by the assignee of the present applicants, while the size and 
pattern of punch-out areas 2' correspond with a competitor's model. 
Additional patterns could be added as desired, even with such overlapping 
as may be necessary to accommodate further models as may be, or as may 
become, available. As a result, said array 4 of patterns of various 
configurations is generated. 
The punch-out areas 2, 2' are separately identified on the back of the 
Sheet 1 by printed indicia such as "A" and "B" as shown, preferably 
together with instructions shown schematically, as 5 to the user to push 
out those areas marked A, B or C, etc., according to the model which the 
user is about to operate. Thus there may also be printed on the sheet 1 a 
list of models together with the respective letter or other suitable 
symbol or indicium identifying which holes are to be formed. In any event, 
it is evident that the user need not push out any holes if desired. 
Accordingly, the perforations are arranged so that the punch-out areas 2, 
2' are not so easily separated from the sheet 1 as to be dislodged during 
a normal sanding operation. For the disclosed embodiment, a suitable 
perforation size is about one millimeter long; the perforations are also 
spaced apart about a millimeter. 
In a second embodiment, as shown in FIG. 2, sheet 11 is provided with a 
similar array 14 of oval-shaped areas 12, 12'. A third embodiment is shown 
in FIG. 3, in which another similar array 24 of rectangular areas 22, 22' 
is formed in sheet 21. 
The front (not shown) of the sheet 1 appears as an ordinary sheet of 
sandpaper. Moreover, sheets may be provided ready-cut into 1/3 or 1/2 or 
1/4 sizes, as desired, or in full-size sheets, preferably with separable 
or frangible perforated delineations dividing the sheet into the 1/3-, 
1/2- or 1/4-sheet sizes. An example is shown schematically in FIG. 4, in 
which a whole sheet 30 is formed of two half-sheets 31 separated by 
perforation line 36. Arrays 34 of separable areas 32, 32' are also shown 
schematically. 
The above-described embodiments, of course, are not to be construed as 
limiting the breadth and scope of the present invention. Modifications, 
and other alternative constructions, will be apparent which are within the 
spirit and scope of the invention as defined in the appended claims.