U.S. patent number 3,638,362 [Application Number 05/057,643] was granted by the patent office on 1972-02-01 for portable grinder apparatus.
Invention is credited to Gottlieb Stoll.
United States Patent |
3,638,362 |
Stoll |
February 1, 1972 |
PORTABLE GRINDER APPARATUS
Abstract
A portable grinding apparatus has a working plate movably
mounted on a casing and oscillatable by a motor carried by the
casing. The plate includes a top member having downwardly directed
flanges and a bottom member adapted to carry on its lower surface
on abrasive material and closing the open bottom of the top member.
A pipe for connection to a suction device extends through the top
member into the interior of the space between the top and bottom
members. The bottom member and the grinding material have aligned
holes to allow the flow of air and entained chips through the space
to the outlet pipe.
Inventors: |
Stoll; Gottlieb (73 Esslingen
am Neckar, DT) |
Family
ID: |
5741160 |
Appl.
No.: |
05/057,643 |
Filed: |
July 23, 1970 |
Foreign Application Priority Data
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Jul 29, 1969 [DT] |
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P 19 38 350.7 |
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Current U.S.
Class: |
451/353; 451/357;
451/456 |
Current CPC
Class: |
B24B
55/105 (20130101) |
Current International
Class: |
B24B
55/00 (20060101); B24B 55/10 (20060101); B24b
023/00 () |
Field of
Search: |
;51/17MT,17R,273,177,17T,17TL |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Armstrong; William R.
Claims
Having thus fully described my invention, what I claim as new and
wish to secure by Letters Patent is:
1. A portable grinding apparatus comprising, in combination, a
casing, a driving motor within said casing having a drive shaft, a
working plate movably mounted and supported on said casing so as to
be movable within a single plane, s driving connection between said
drive shaft of said driving motor and said working plate, said
driving motor causing said working plate to perform an oscillating
movement within a plane rectangular to the axis of said drive
shaft, a grinding element, said grinding element being mounted on
the underside of said working plate turned away from said driving
motor, said grinding element being releasably attached to said
working plate, a suction device for sucking up the chips produced
during grinding operation, means connecting said suction device
with at least a portion of the space adjacent the said working
plate, wall means cooperating with said working plate and forming
therewith a hollow space, through bores in said working plate, said
through bores extending from said hollow space to the underside of
said working plate turned away from said drive motor, thereby
enabling said hollow space to communicate with the outer atmosphere
and the space adjacent the underside of said working plate, a
suction opening in said wall means, said suction opening serving to
connect said hollow space with a suction device.
2. The portable grinder apparatus set forth in claim 1 in which the
said grinding element is a flexible abrasive material and in which
the said through bores project downwardly through the bottom
surface of the said working plate and through the flexible abrasive
material.
3. The portable grinder apparatus set forth in claim 2, wherein the
said suction device forms part of the said grinder apparatus and is
driven by the latter's drive motor.
4. The portable grinder apparatus set forth in claim 2, wherein the
said suction device is a separate, independently driven device,
said apparatus including, connected to the said suction opening, a
flexible suction line.
5. The portable grinder apparatus set forth in claim 1, wherein the
working plate is substantially rectangular and the through bores
extend at right angles in relation to the plane of the abrasive
element and are equally spaced along at least two lines arranged
symmetrically in relation to the longitudinal middle axis of the
said working plate and in parallel relation to the longitudinal
edges of the said working plate.
6. The portable grinder apparatus set forth in claim 1, wherein the
suction opening is located within the rear portion of the working
plate and on the upper surface opposite the grinding elements and
extends through the longitudinal middle plane of the working plate
which forms a right angle with the plane of the grinding element,
the longitudinal middle plane forming the plane of symmetry of the
suction opening.
7. The portable grinder apparatus set forth in claim 1, wherein the
said working plate is divided along a plane extending essentially
in parallel to the plane of the grinding element, and wherein said
working plate comprises on the one hand an upper portion suspended
on the housing of the grinder apparatus, and, on the other hand, a
bottom portion which is detachably connected with the upper portion
along the plane of division, the upper portion comprising an
essentially box-shaped frame which is open towards the plane of
division facing the plane of division, with the suction openings
extending upwardly through such frame, while the bottom portion
comprises a flat plate which rests on the free edges of the frame
which face the plane of division and whose rectangular dimensions
correspond essentially to the rectangular dimensions of the frame
and which is in contact with the edges of the frame, thus closing
the cavity existing between the frame and the plate, and which is
detachably connected with such edges and which is formed of a
material which resists bending and torsion.
8. The portable grinder apparatus set forth in claim 7, wherein the
plate forming the bottom portion comprises, on its surface opposite
the cavity, a rigidly mounted plate of resilient material, which
carries on its surface opposite the cavity the grinding element
which comprises a web of abrasive paper, clamping members mounted
on the frame releasably engaging said web, and in that the flat
plate as well as the resilient plate and the abrasive paper are
provided with aligned passage bores, which connect the cavity
existing between the upper portion and the bottom portion with the
bottom surface of the abrasive paper.
9. The portable grinder set forth in claim 8, wherein at least part
of the passage bores which extend essentially vertically in
relation to the plane formed by the abrasive paper are provided
with a shunt opening extending from one side of the bottom portion
into the passage bore and serving to direct air drawn off from the
zones adjacent the sides of the working plate into the associated
passage bore.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a portable grinding apparatus with a
suction arrangement for the removal of chips.
SUMMARY OF THE INVENTION
The present invention relates to a portable grinder apparatus and
more particularly to an apparatus in which a housing encases a
drive motor which sets into oscillating movement a working plate
which is movably suspended on said housing and which carries on its
lower surface an easily exchangeable grinding medium, such as
abrasive paper or a web of grinding cloth, the said oscillating
movement being contained in a single plane, and in which the
produced chips are removed by a suction device.
The primary object of the present invention is to provide a
grinding apparatus of the kind with only small space requirements
and with the aid of which also small angles and corners can be
worked wherein the outer edge of abrasive paper is allowed to reach
right into angles, corners or the like.
Another object of the invention is to provide a portable grinder
apparatus of the type described above in which the working plate
comprises a hollow space within itself, the latter being
interconnected on the one hand with passage openings projecting
downwardly through the bottom of the working plate and also through
the abrasive paper and, on the other hand, with a suction opening
connecting it with the above mentioned suction device.
Yet another object of the invention is to provide a device of the
kind in question in which all components of the suction device are
extremely simple and obtainable at low cost.
A still further object of the invention is to provide a device of
the character described with which the suction effect is also
considerably improved due to the shorter suction paths, which are
of importance flat when working even surfaces but still more when
working curved surfaces, in which case the suction paths of the
device of the invention are even shorter, which again considerably
increases the suction power.
Another object of the invention is to provide a device of the
above-mentioned character with which the arrangement can be used
with portable grinders of any type, wherein the suction device may
be part of the portable grinder and driven by the latter's own
drive motor, or else a separate, independently driven suction
device which is connected to the suction opening of the working
plate through an essentially flexible suction line. In the latter
case, the suction devices may take any form, from domestic vacuum
cleaners to industrial vacuum cleaners, the selection of the device
and, thus, the suction power depending on the material to be ground
in each individual case.
Other objects and advantages will appear hereinafter and while I
show herewith and will describe a preferred form of construction, I
desire it to be understood that I do not limit myself to such
preferred form but that various changes and adaptations may be made
therein without departing from the spirit of my invention as
hereinafter claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details and advantages of the invention will become
apparent from the following drawings, in which:
FIG. 1 is a side elevation of a portable grinder according to the
invention with a detached sheet of abrasive paper;
FIG. 2 is a partial vertical cross section along the longitudinal
axis of the grinder shown in FIG. 1 and
FIG. 3 is a diagrammatic representation of and a vertical cross
section through part of the grinder shown in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, a portable grinder 1 comprises a drive motor
enclosed in a housing 2, the said drive motor setting a working
plate 3 which is movably suspended on the said housing 2 into an
essentially straight-lined or slightly curved oscillating movement
within plane 4, in which a grinding agent, such as a sheet of
abrasive paper or grinding cloth 5 is located which rests on the
lower surface A of the working plate 3 when the device 1 is in
operating condition and which is held against the working plate by
clamping means 6 which provide for easy exchangeability. A knob 7
is mounted on the housing 2 at the front end of the device 1, while
the rear side of the housing carries a rigid shank or handle 8
which serves to hold the device, as is the case also with knob
7.
In the device of the invention, the working plate 3 comprises a
cavity 9 opening on the one hand on the bottom surface A of the
working plate 3 through passage openings. 11, 11' or bores
extending essentially perpendicularly to the plane of the abrasive
paper 5 and penetrating through the latter at 10, 10', and being
connected on the other hand through a suction opening 12 with a
suction device not shown in the drawing. The said suction device
may either be part of the grinder 1 and driven by the latter's own
drive motor, or else consist of a separate unit which has its own
drive and is, therefore, driven independently of the grinder 1 and
which is connected to the suction opening 12 of the working plate
3. The connection between the suction device and the grinder may
consist, for instance, of a flexible suction line 13. As is
apparent from the drawings, the cavity 9 extends essentially over
the whole face of the working plate 3. In the essentially
square-shaped working plate 3, the passage openings 10, 10', 11,
11', are equally spaced along two lines arranged symmetrically in
relation to the longitudinal middle axis of the working plate 3 and
in parallel relation to the longitudinal edges of the working plate
3, the suction opening 12 of the cavity 9 in the working plate 3,
which is connected to the suction device, extending conveniently
through the longitudinal middle plane of the working plate 3
rectangular to the plane 4 of the abrasive paper 5, and being
arranged within the rear portion of the working plate 3 beneath the
handle 8 mounted on the housing 2 and being contained within the
upper surface B turned away from the abrasive paper 5 of the
working plate 3. Depending on the space available, the suction
opening 12 may be provided either at a right angle to the plane 4
or at an angle different from a right angle in relation to the rear
portion of the working plate 3 extending underneath the handle 8.
As is apparent in particular from FIGS. 1 and 2, a tubular
connection socket 19 is provided on the working plate 3, which
forms an extension of the suction opening 12 in the direction
towards the upper surface B of the working plate 3 and which serves
to connect with the suction line 13.
The working plate 3 is subdivided along a plane 20 essentially
parallel to the plane 4 and comprises on the one hand an upper
portion 21 which is suspended and mounted on the housing 2 of the
grinder 1 and which consists of an essentially box-shaped frame 23
which is open towards the plane of division 20 and which contains
on its upper surface the suction opening 12, and comprises, on the
other hand, a bottom portion 22 which is detachably connected to
the upper portion 21 along the plane of division 20 and which
comprises a flat plate 24 consisting, for instance, of metal such
as steel or aluminum which rests on the frame edges 23 facing the
plane of division 20, the said plate bearing against the frame
along the frame edges, whereby the cavity 9 comprised between the
frame 23 and the plate 24, is sealed, the said plate being further
detachably connected, for instance, by means of screws 25 inserted
from the upper frame surface B. The plate 24 comprised in the
bottom portion 22 is provided with passage bores 26, 26' which also
extend through the abrasive paper 5 at 10, 10' (FIG. 3) and which
interconnect the cavity 9 existing between the frame 23 and the
plate 24 with the bottom surface A of the working plate 3 and,
thus, with the area in which chips are encountered during the
grinding of workpieces. The plate 24 forming the bottom portion 22
has on its surface opposite the cavity 9 a rigidly connected, for
instance, glued-on plate 27 of resilient material, such as rubber
or plastic, which carries on its surface opposite the cavity 9 a
web of abrasive paper 5 (FIG. 3) which is made easily exchangeable
by means of the clamping members 6 provided on the frame 23, the
stiff, for instance, metallic plate 24, the resilient plate 27 and
the abrasive paper 5 being provided with flush passage bores 26,
26', 11, 11' and 10, 10', which interconnect the cavity 9 existing
between the upper portion 21 and the bottom portion 22 with the
bottom surface A of the abrasive paper 5 carrying the abrasive
grain and which thereby serve to open the cavity 9 to the exterior
on the side of the surface A.
At least part of the flush passage bores 10, 11, 26 which are
provided essentially perpendicularly relative to the plane 4 of the
abrasive paper, is provided with shunt openings 28, 28' extending
from one side (edges 15, 16) of the bottom portion 22 into the
passage bore 10, 11, 26, which shunt openings serve to direct air
drawn off the zones adjacent the sides of the working plate 3
(arrows 29, 29' in FIG. 3) into the associated passage bores. As
is, furthermore, apparent from FIG. 3, air containing grinding
chips is drawn off from the bottom surface A through the passage
bores 10, 11, 26 or 10', 11', 26' (arrows 30, 30'). The two
indrafts 29, 30 or 29', 30' mix within the passage bore and proceed
in accordance with the suction effect in the direction of the
arrows 31, 31' towards the suction opening 12. In the embodiment
shown in the drawings, each passage opening 10, 11, 26 or 10', 11',
26' is provided with such a shunt opening 28, 28'. As is apparent
from FIG. 3, the shunt opening 28, 28' are provided between the
resilient plate 27 and the abrasive paper on that surface of the
said resilient plate which faces the abrasive paper 5. The said
shunt openings take thereby essentially the form of a groove which
extends essentially within the plane 4 formed by the abrasive paper
5 and whose sides diverge towards the abrasive paper. The said
shunt openings 28, 28' serve the purpose to draw off any chips that
may be encountered at the sides of the working plate 3 and, at the
same time, to prevent any excessive adhesion between the abrasive
paper 5 and the workpiece surfaces caused by the vacuum existing in
the passage bores 10, 11, 26 or 10', 11', 26'.
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