Note: Descriptions are shown in the official language in which they were submitted.
216788
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POLE MOUNTED VACUUM SANDER
BACKGROUND OF THE INVENTION
The invention relates to tools for manual sanding
and more particularly to a pole-mounted sanding device
provided with a vacuum connection for drawing off the dust
created by the sanding action.
The sanding of wood, drywall or plaster is
typically accomplished using a sanding block which is hand-
held and to which sheets of sand paper can be removablyattached. The dust generated by the sanding action, par-
ticularly in the case of drywall, falls freely in the work
area and therefore requires subsequent cleanup.
Various devices have been designed to provide a
vacuum connection to the sander head to pick up the dust
generated by the sanding action in the vicinity of the
sander head. The present applicant's United States Patent
no. 5,283,988 issued February 8, 1994 discloses a vacuum
sander of the type comprising means for connecting a source
of vacuum, a base for attaching a back-up pad and means for
releasably attaching an abrasive, air-permeable sheet. In
that device, the back-up pad was designed with a raised
perimeter provided with a plurality of grooves extending
from the outer edge to an inner chamber, which improved the
ability of the device to pick up dust around the edges of
the sanding surface.
Mehrer U.S. Patent no. 4,062,152, discloses a
sander which is connected to a vacuum source by a hollow
tubular handle. A porous abrasive sheet is mounted on the
front surface of a backing plate which has a number of
bores which provide an air passageway from the abrasive
sheet to a manifold which in turn communicates with the
tubular handle by a hollow sleeve universally mounted on
the sander body. A problem with pole mounted vacuum
sanders however is that one longitudinal edge of the sander
head tends to lift off the wall as the head is moved up or
down, causing it to lose suction and contact with the wall.
There remains a need therefore for a pole mounted
vacuum sander which has a universal joint connection
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between the pole and the sander head which is secure enough
to prevent the sander head from losing contact with the
surface being sanded during use.
SUMMARY OF THE INVENTION
The present invention provides a pole mounted
sanding device for sanding a working surface, where the
device is of the type comprising a base for attaching a
back-up pad, means for releasably attaching an abrasive
sheet to the base and universal means for connecting the
pole to the base. The universal joint means includes a
contact surface on the pole and a camming surface mounted
on said base whereby the pole can be pivoted between a
first position wherein the pole is perpendicular to the
broad surface of the back-up pad and the contact surface is
spaced from the camming surface to a second intermediate
position where the contact surface bears against the
camming surface to a third position where the pole is
angled to the broad surface of the back-up pad and the
contact surface is spaced from the camming surface or bears
against the camming surface with less force than in the
intermediate position. Preferably the device is of the
type comprising means for connecting a source of vacuum to
the base and the abrasive sheet is air permeable.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate a preferred embodi-
ment of the invention:
Fig. 1 is a perspective view of the invention;
Fig. 2 is a partial cross-section of the inven-
tion taken along lines A-A of Figure 6, with clamping bars
removed;
Fig. 3 is a partial cross-section of the inven-
tion taken along lines B-B of Figure 6;
Fig. 4 is a cross-sectional view as in Figure 2,
with the pole mount angled to one side;
Fig. 5 is a side view of the invention shown in
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Figure 1 with the flexible boot removed to illustrate the
operation of the camming element;
Fig. 6 is a top view of the invention shown in
Figure 1 with the flexible boot and universal assembly
5 removed and air passages shown in dotted outline; and
Figure 7 is a bottom view of the back-up pad.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
The pole mounted vacuum sander of the invention
is designated generally by reference numeral 10. It com-
prises a base member 12 of moulded plastic which has a
hollow, upwardly extending air chamber section 14 with
central aperture 16, the periphery 18 of which forms a lip
to receive the edge of a flexible rubber boot 17. Base
15 member 12 is provided with two holes 11 and 13 (Fig. 6)
which communicate with the interior 15 of chamber 14. Base
12 is provided at either end thereof with a clamp 19,
consisting of clamping bar 20, wing nuts 22 and bolts 24
which are of standard construction, for releasably securing
20 a sheet of abrasive, air-permeable mesh (not shown) of the
type sold by the 3M Company for use as a gyproc filler mesh
sanding pad. Fixed to the bottom of base 12 is a moulded
neoprene rubber backing pad 23, also provided with two
holes 25 and 27 (Fig. 7) which are co-extensive with holes
25 11 and 13 in base 12. Pad 23, as disclosed in applicant's
United States Patent no. 5,283,988, has a series of raised
support ridges 29 and raised perimeter 130 which extend
upwardly from the inner recessed surface 31 of pad 23.
Perimeter 130 is provided with regularly spaced ridges 135
30 and grooves 137 forming a rippled surface.
Pipe connector 30 is a hollow tube of moulded
plastic provided with threads 32 which receive the threaded
end of a hollow pole tnot shown) which in turn is connected
to a standard shop vacuum hose. The hollow interior 35 of
35 pipe connector 30 iS also tapered to directly receive a
vacuum hose and communicates along the hollow central axis
37 into the hollow chamber 19 formed under boot 17. Pipe
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connector 30 has an aperture 34, in a section of the
connector 31 of reduced diameter, opening to the interior
of pipe connector 30. A series of ratchet ridges 33 are
provided along the upper edge of section 31 and an annular
collar 36 (not shown in Fig. 2 through 6) having a cutout
rotates in section 31. The interior surface of collar 36
also has a series of ridges so that enough friction exists
between ridges 33 and collar 36 to retain collar 36 in a
set rotational position until an appropriate rotational
force is applied. In this way the flow of air through
aperture 34 can be regulated by rotation of collar 36.
When a source of vacuum is connected to pipe connector 30,
the degree of vacuum applied to the base of the sander is
thus regulated by rotating collar 36, permitting the amount
of suction applied to the wall to be varied in the event
that the pad is sticking to the wall due to overly great
suction, for example.
Pipe connector 30 also is provided with a groove
40 which receives the upper edge of flexible rubber boot
17. Pipe connector 30 is connected to base 12 by a univer-
sal connection as follows. The lower end of pipe connector
30 is bifurcated, having two parallel extensions 42 which
pivot on rivet 44 which extends through T-element 48. T-
element 48 is connected to a cylindrical tube 50 which
similarly pivots on rivet 52 which extends through and is
secured in base 12.
As illustrated in Fig. 5, T element 48 has an
upper camming surface 60, the central surface portion 62 of
which follows a circular arc 63, but the outer surface
portions 64 of which extends outwardly beyond the arc of
radius 63. Roller 56 is mounted between extensions 42 for
rotation on pin 58 and is positioned so that when pipe
connector 30 is in the position shown in Figure 2, roller
56 clears surface portion 62 without contact, but in the
position shown in Figure 5, roller 56 bears tightly against
surface portion 64. Due to the shape and material of T-
element 48, and cut-outs 70, and the shape of surface
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portions 64, the ends of T element 48 give slightly under
pressure and once the roller is in the position shown in
Figure 5 it tends to bind in that position and increased
rotational force is required to move it out of that posi-
tion to a raised position.
In operation, a pole attached to a source of
vacuum is secured to pipe connector 30 and vacuum sander 10
is raised into position on a wall, for example. The pole
and attached pipe connector 30 are then pivoted to the
position shown in Fig. 5 to tighten the pole into position
and the sander can then be operated on the wall without
undue releasing from the wall surface. To permit a freer
universal movement of the sander 10, the pole is rotated
upwardly to bring roller 56 out of contact with T element
48.
As will be apparent to those skilled in the art,
various modifications and adaptations of the structure
above described may be made without departing from the
spirit of the invention, the scope of which is to be
construed in accordance with the accompanying claims.
