Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to rotary sanders a~d in
particular to an improved suction device for use in such
a sander. ~ - `
Substantial problems have been encountered in grinding
fiberglass such as in automobile bodies. When ground,
fiberglass is very sticky and it cuts into small string-like
portions and plugs up air channels in conventional vacuum
housings. It also sticks to automobile bodies and it is very
hard to clean the surface on which it i~ stuck~ When grbund ;;
with a coarse disc, fiberglass also brleaks up into small pieces
and chunks and it is difficult to draw the heavy particles
through normally available air suction channels. Further,
flberglass normally has to be cut with a high speed machine
and the additional centrifugal force applied by such machines
tends to throw the material away from the ground surface and
from the area of suction.
Another problem involved Witll normally available
vacuum housings is that if an operator is applying suction
with a pipe from a large chamber over the grinding mechanism,
the suction is not concentrated powerfully to one point where
it is needed.
In other words, to a great extent, most of the time
when grinding is being done, only part of the back-up pad and
abrasive disc is placed on the surface to be ground. The
remainder of the back-up pad is held upwardly and is away
from the ground surface. With pipe from a large suction chamber
over the grinder, the large heavy particles ground from the
surface tend to fall out and settle on that point and the
suction being dispersed only carries the lighter particles
away from the ground surface and into the vacuum apparatus.
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SUMMARY OF THE INVENTION
In the present apparatus, most of the vacuum apertures
in the back-up pad are covered and the suction or vacuum is
directed in the main to the spot that the operator is grinding
50 that the operator has a powerful suc~ion on the spot that
is being cut by the abrasive material.
In accordance wi~h one broad aspect of the present
inventionr there is provided an improved suction housing for
rotary sanders comprising a suctlon housing for connection to
a drive head and which includes a back-up pad mounted within
~he housing for rotation therein. The pad has a plurality of
elongated apertures extending completely through the surface
thereo and are adapted for alignment with apartures of like
formation in an abrasive disc which is secured to the bottom of
a pad. The housing includes a bottom wall spaced above and ~ -
ovexlying a substantial portion of the upper surface of the pad
and a collection chamber contiguously formed with said bottom
wall including side walls and a top wall which is spaced
~ubstantially above the pad. The co:Llection chamber occupies
only a small portion of the surace area of the pad to thereby
apply suction on the pad in a concentrated area and an exhaust -
suction pipe extends from the upper wall of the collection
chamber for connection to a vacuum applying apparatus.
In the present invention, the suction housing is so
designed a~ to reach almost to the very edge of the back-up pad
and the vacuum pipe occupie~ an important place on top of the
suction housing. All grinders turn to the right and drive the
ground material to the rîght as well thereby throwing all the
ground material to the rlght when the material goes beyond the
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periphery of the grinding pa~. In the present invention suction
i8 applied completely through the back-up pad an~ in order to
prevent the ground material to fly at a tangent beyond the back-up
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pad, a collection chamber .is provided immediately above the
edge of the pad which is applied to the surface to be ground.
Dust particles rom their own weight stick to the left side
of the apertures under the influence of centrifugal force and
therefore the weight of the ground material ~ends to go to the
lPft. With an angular disposition of the suction pipe from
right to left, the vacuum draws the material through the holes
in the same direction as the material originally intended to
take. Th~ pswer and direction of the vacuum together with the
weight of the ground material work together with the centriugal
force to draw the material better and faster from the sanded
surface through the vacuum tube.
The invention is illustrated in the accompanying drawings
in which:
. Figure 1 is an exploded view in perspective of the
improved vacuum housing assembly;
Figure 2 is a view of the bottom surface of the
housing, and
Figure 3 is a perspective view of the housing in
assembled form.
Re~erring to Figure 1, the assembly generally indicated
at 10 includes a vacuum housing 12, back-up pad 14 and abrasive
disc 16~ Housing 12 comprises a peripheral wall 18 having a
bottom wall or plate 20 (Figure 2) and a central upstanding
collar 22 adapted to be secur~d to a drive housing 24 (Figure 3)
by means o~ a strap or the like 26. As seen in all figures,
the housing 12 includes a collectox chamber 28 which includes
an opening 30 in the plate 20, side walls 32 and a top wall 34
from which a vacuum pipe or exhaust pipe 36 extends at an angle.
30 . The back-up pad 14 has an upper surface 38 of solid
material such a~ a hard plastic and has an aperture 4 0 threaded
to engage the abovementioned drive member. The pad 14 has a
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plurality of apertures 42 which are elongated in form and extend
completely through the back-up pad as shown in the small ~
cut-away portion thereof and which lie~very-near~the extreme
outer edge of the pad so a3 to be in registry with similar
holes 44 in the abrasi~e disc 16 sh~wn in Figure 1. Disc 16 i~
applied to the bottom surface of pad 14 by centering-means;and
i5 held thereon by the snap ring 46 which engages the fabric
skirt 48 on the abrasive disc 16 and which secures the skirt
into the peripheral groove S0 in the pad 14 as shown in Figure
3.
The disc 14 is pro~ided with an upstanding flange 52
which fits within the depenaing portion 54 of the side wall 18
of the housing 12 to prevent any outside air from entering the
confines of the housing and this is enhanced by means of a
resilient band 56 which is pIaced on the outside of the suction
chamber and which extends downwardly o~er the skirt thereof to
effectively seal off any outside air to be drawn into the
confines of the chamber.
The plate 20 (Figure 2) is spaced slightly above the
upper surface of the apertures 42 so that they are not
completely sealed off as some ground material may not be
completely drawn in by the collector chamber 28 due to the
high speed of rotation of the pad 14 and some material may pass
by the chamber on the first revolution but be picked up on the
next.
It will be appreciated that with the collector chamber
28, most of ~he suction applied through exhaust pipe 36 is
concentrated in the area where it ~s mostly needed, the area
being ground by the operator. it has been found that in
concentrating the ~acu~ in this manner, all ground material
i~ instantly drawn through the paper, ba~k-up pad and int~ the
suction chamber 28 to preven~ the material from clogging the
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suction holes in the pad and disco - -
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