U.S. patent number 3,885,355 [Application Number 05/380,618] was granted by the patent office on 1975-05-27 for pneumatically driven grinder.
This patent grant is currently assigned to Ushio Co., Ltd.. Invention is credited to Masakazu Kakimoto.
United States Patent |
3,885,355 |
Kakimoto |
May 27, 1975 |
Pneumatically driven grinder
Abstract
The air motor has substantially the size of a standard fountain
pen and includes an extruded cylindrical casing formed with a
circular cross-section eccentric inner surface which has annular
grooves in its forward part and a smooth surface, substantially
coincident with the bases of the grooves, in its rear part. The
grooves constitute air supply and exhaust passages, a retainer
groove and a pin groove. A front retainer closes the forward end of
the casing and has a tongue projecting into the retainer groove to
maintain a predetermined angular orientation in the casing, and a
rear retainer is seated against the ribs defining the grooves in
the forward portion of the casing and has a tongue projecting into
the retainer groove to maintain a relative angular orientation with
respect to the front retainer. A motor cylinder is mounted in the
casing between the two retainers and has air supply and exhaust
ports communicating with the air supply and exhaust passages,
respectively. A vane type rotor is rotatably supported in the two
retainers, through bearings, and is eccentric to the motor
cylinder. The forward end of the rotor is formed with a shaft by
means of which a grinder or another tool can be secured to the
rotor. The portion of the casing rearwardly of the rear retainer
constitutes an air supply and control chamber in which there is an
air filter means, and the air passing through the filter means
flows through supply passages in the rear retainer into the air
supply passage. A connection is provided at the rear of the casing
for connecting the air motor to a source of air under pressure, and
a manually operable grip threaded on this connection controls the
supply of air under pressure to the supply and control chamber. In
a modification of the air motor, the exhaust air flows rearwardly
along the exterior surface of the motor cylinder and through sound
absorbing means to exhaust ports leading to the atmosphere or to an
exhaust line.
Inventors: |
Kakimoto; Masakazu (Aichi-gun,
JA) |
Assignee: |
Ushio Co., Ltd.
(JA)
|
Family
ID: |
27281821 |
Appl.
No.: |
05/380,618 |
Filed: |
July 19, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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274905 |
Jul 25, 1972 |
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Foreign Application Priority Data
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Feb 19, 1972 [JA] |
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47-17424 |
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Current U.S.
Class: |
451/359;
451/295 |
Current CPC
Class: |
F01C
21/186 (20130101); F01C 1/3442 (20130101); B24B
23/028 (20130101) |
Current International
Class: |
F01C
1/00 (20060101); B24B 23/00 (20060101); B24B
23/02 (20060101); F01C 1/344 (20060101); B24b
023/02 () |
Field of
Search: |
;418/15,47,70,181,270
;415/503 ;51/134.5F,17PT,17T ;251/122 ;173/163 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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997,904 |
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Aug 1952 |
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FR |
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842,253 |
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Jul 1960 |
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GB |
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Primary Examiner: Whitehead; Harold D.
Attorney, Agent or Firm: McGlew and Tuttle
Parent Case Text
This is a division of application Ser. No. 274,905 filed July 25,
1972.
Claims
What is claimed is:
1. A grinder driven by an air motor comprising, in combination, a
tubular extrusion defining a relatively elongated tubular casing
having a circular cross-section inner surface which is eccentric to
the axis of said casing and which is formed with angularly spaced
longitudinal grooves extending through at least a portion of the
length of said casing and defining air supply and exhaust passage
means; means dividing the interior of said casing into a front
motor chamber having said grooves therein and a rear air supply and
control chamber, a tubular motor cylinder in said motor chamber
having a smooth cylindrical outer surface engaging the circular
cross-section inner surface of said casing and having radial ports
communicating with said air supply and exhaust passage means; an
air pressure rotated cylindrical rotor rotatably mounted in said
motor cylinder; a shaft projecting from the front end of said rotor
for connection to a tool to be driven by said motor; said dividing
means having ports connecting said supply and control chamber to
said air supply passage means; exhaust port means connecting said
exhaust passage means to atmosphere; a connection at the rear of
said casing for connecting said air motor to a source of air under
pressure, a manually operable control valve controlling
communication between said connection and said supply and control
chamber; the front end of said casing being externally threaded; a
grinder housing threaded onto the front end of said casing; a first
bevel gear secured to said shaft and disposed in said grinder
housing; a second bevel gear meshing with said first bevel gear;
anti-friction means rotatably mounting said second bevel gear in
said grinder housing for rotation about an axis perpendicular to
the axis of said first-mentioned shaft; and means securing a
grinder to said second bevel gear.
2. A grinder driven by an air motor, as claimed in claim 1, in
which said second bevel gear has a relatively elongated hub
threaded at its outer end; a retainer threaded on the hub of said
second bevel gear; said means securing said grinder to said second
bevel gear comprising a bolt engaged with said grinder and
extending through a central opening in said retainer and having a
threaded end engaged in a threaded axial bore in the hub of said
second bevel gear.
Description
FIELD AND SUMMARY OF THE INVENTION
This invention relates to air motors of the rotary type operated by
compressed air, and to an air-operated grinder operable by the air
motor.
The objective of the invention is to provide an air motor of high
efficiency which can be manufactured in mass production or at a
reduced cost.
Another objective of the invention is to provide an air motor of
small size, only a little larger than a standard fountain pen, and
which is extremely convenient to use.
A further object of the invention is to provide a small-size
grinder operatively connected to the small-size air motor.
For an understanding of the principles of the invention, reference
is made to the following description of typical embodiments thereof
as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is an axial sectional view of the air motor;
FIG. 2 is a cross-sectional view taken on the line 2--2 of FIG.
1;
FIG. 3 is a cross-sectional view taken on the line 3--3 of FIG.
1;
FIG. 4 is a cross-sectional view taken on the line 4--4 of FIG.
1;
FIG. 5 is a cross-sectional view similar to FIG. 4 but illustrating
the rotor in a different angular position;
FIG. 6 is a side elevation view, partly in section, illustrating
one form of air grinder connected to the air motor;
FIG. 7 is a view similar to FIG. 6 illustrating another form of
grinder connected to the air motor;
FIG. 8 is a view, similar to FIG. 1, illustrating a modified form
of the air motor;
FIG. 9 is a cross-sectional view taken on the line 9--9 of FIG. 8;
and
FIG. 10 is a cross-sectional view taken on the line 10--10 of FIG.
8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIGS. 1 through 5, an air motor embodying the
invention includes a cylindrical casing 1, a motor cylinder 2, and
a rotor 3 rotatable in cylinder 2. The motor further includes an
air supply valve member 4 having a connection member for connecting
the air motor through a hose 5, indicated in dot and dash lines, to
a source of air under pressure. The air flows from valve member 4
through an filter 6 and through air supply ports in a back retainer
8. From the ports in back retainer 8, the air flows through an air
supply passage a and through air supply ports 13 into motor
cylinder 2 to drive the vaned rotor 3 which is eccentric with
respect to motor cylinder 2 and carries radially displaceable vanes
or blades 15. Air leaves motor cylinder 2 through air ports 14 and
flows through air passages b, b to exhaust ports 9 in front
retainer 7, from which the exhaust air is discharged to atmosphere.
As stated, the air motor, generally indicated at A, is a small size
air motor, having dimensions only slighly larger than those of a
standard fountain pen.
Tubular or cylindrical casing 1 is formed of a suitable material,
such as aluminum, by extrusion, during which the eccentric circular
cross-section inner surface of casing 1 is formed with longitudinal
grooves a, b, b, c, and d, the grooves being spaced angularly from
each other. After the extrusion operation, the rear half of the
casing 1 is machined to remove the ribs defining the longitudinal
grooves, so as to have a relatively smooth inner surface with an
inner diameter slightly larger than the base diameter of the
longitudinal grooves.
Longitudinal groove a constitutes an air supply passage and
longitudinal grooves b constitute exhaust passages. Groove c is a
locking or retaining groove, and groove d, is a pin groove for
receiving a retaining pin. Front retainer 7 is seated against a
shoulder at the forward end of casing 1, and rear retainer 8 is
seated at a shoulder formed by the machining of the rear half of
the casing 1. Rear retainer 8 divides the casing into a front motor
chamber I and a rear air supply and control chamber II. Chamber I
is provided with the longitudinal grooves a, b, b, c, and d, and
chamber II does not have any grooves.
Front and back retainers 7 and 8 are provided with respective
projecting tongues 7' and 8' engaged in retainer or locking groove
c, so as to maintain a predetermined angular relation between the
front and back retainers. In this predetermined angular relation,
exhaust ports 9, 9 of front retainer 7 are aligned with respective
exhaust grooves b, while the front ends of grooves a, c, and d are
blocked or closed by front retainer 7. In the predetermined angular
relation orientation, the air supply port 10 in back retainer 8 is
aligned with air supply passage or groove a, whereas the rear ends
of grooves b, b, c, and d are closed by back retainer 8. Front
retainer 7 and back retainer 8 mount anti-friction bearings which
rotatably support the motor rotor 3, and front retainer 7 is
maintained in position by a front cover 11 threaded on to casing 1.
Back retainer 8 is maintained in position by the valve member 4
threaded into casing 1 and this valve member also retains filter 6
clamped in position.
The motor cylinder 2 is disposed in the front motor chamber I, and
clamped between the front retainer 7 and a rear retainer 8. Motor
cylinder 2 is retained in a predetermined orientation by means of a
pin 12 engaged in the longitudinal groove d and in a longitudinal
groove in the outer surface of motor cylinder 2. In this
predetermined orientation of motor cylinder 2, axially spaced air
supply ports 13 are in communication with air supply passage or
groove a, and axially spaced exhaust ports 14 are in communication
with both exhaust grooves or passages b.
As mentioned, rotor 3 is rotatably mounted in the anti-friction
bearings in front retainers 7 and back retainer 8, in such a
fashion that it rotates eccentrically in motor cylinder 1. Also as
mentioned, rotor 3 has the radially reciprocable blades 15 mounted
therein. A drive shaft 16 extends from the front end of rotor 3 to
project outwardly of the front end of the motor for connection to a
grinder or the like to be driven by the motor.
The valve member 4 retains back retainer 8 in position through the
medium of a ported plug 17 engaged between valve member 4 and back
retainer 8. The filter 6 is located in the path of air supply from
hose 5 into the air supply and control chamber II. A manually
operable grip 18 is threaded onto valve member 4 so that its inner
end may be displaced axially relative to the valve seat 4' on valve
member 4 to control the cross sectional areas of air supply ports
4". It will be noted that manually operable grip 18 extends
rearwardly from the rear end of casing 1.
To operate the motor, the air hose 5 is connected to a source of
air under pressure, and grip 18 is manually turned to open the air
flow ports 4". Air under pressure then flows through the interior
of valve member 4 and through air ports 4" to flow through filter 6
and the ports or plugs 17 to the air supply port 10 in rear
retainer 8. The air flows into air supply passage or groove a and
through inlet ports 13 in with the interior of motor cylinder 2
where it acts on blades 15 to rotate rotor 3. The air is discharged
from motor cylinder 2 through exhaust ports 14 into exhaust
passages or grooves b and then is discharged to atmosphere through
ports 9, 9 in front retainer 7. Thus, rotor 3 rotates to rotate the
shaft 16.
Referring to FIGS. 6 and 7, as shown in FIG. 6, the air motor A is
connected to operate a grinder by inserting the grinder shaft 21
into shaft 16 and retaining the grinder shaft in position by means
of chuck 22. When the air motor is operated, a grinding stone 23 at
the tip of the shaft 21 is rotated through shaft 16 and shaft
21.
In the embodiment of the invention shown in FIG. 7, a grinder
housing 24 is screwed onto the front end of air motor A. A bevel
gear 27 secured to the output shaft of motor A meshes with a bevel
gear 25 which is rotatably mounted in housing 24 to rotate about an
axis perpendicular to the axis of the output shaft of motor A. A
grinding disc 26 is secured to the hub of bevel gear 25 by a headed
retaining screw or bolt 28. As indicated in FIG. 7, the manually
operable grip 18 may be knurled if desired.
In the embodiment of the invention shown in FIGS. 8, 9 and 10, the
casing 1 is formed essentially the same as is the casing 1 of the
embodiment of the invention shown in FIGS. 1 through 5. That is,
the air supply groove a, the air exhaust grooves b, the retainer or
locking groove c and the pin groove d are formed only in the front
half or motor chamber of the casing, and the rear half or supply or
control chamber of the casing does not have these grooves. Front
retainer 31 and back retainer 32 are formed with respective tongues
31' and 32' extending into retainer groove c to lock the retainers
with a predetermined relative angular orientation. The motor
cylinder 2, rotor 3, and control valve member 4, together with
manually operable grip 18' are essentially the same as in the
embodiment of the invention as shown in FIGS. 1 through 5, so that
further description thereof is not believed necessary.
In this embodiment of the invention, the rearwardly facing surface
of front retainer 1 is formed with an arcuate groove 33
interconnecting the forward ends of the two exhaust passages b with
the retainer passage c. Front retainer 31 blocks the forward ends
of air supply groove or passage a and pin groove b.
Back retainer 32 is formed with an air supply port 34 communicating
with the air supply passage a, and supplied with air under pressure
through radial passages 39 communicating with a supply pipe 40 in
turn communicating with the valve member 4 having the valve seating
surface 4' cooperating with grip 18' to define the ports 4". Back
retainer 32 is also formed with two exhaust ports 35 each
communicating with a respective air exhaust passage b, and the
forward surface of back retainer 32 is formed with an arcuate
groove 36 interconnecting the rear ends of the two exhaust passages
b and the retainer groove c.
As in the embodiment of the invention shown in FIGS. 1 through 5,
back retainer 32 divides casing 1 into a front motor chamber and
the rear air supply and control chamber. The rear air supply and
control chamber, in the embodiment of the invention shown in FIGs.
8, 9, and 10, contains a sound arrester 37, and is formed with the
exhaust ports 38 through the wall of casing 1. While exhaust ports
38 discharge to atmosphere, the design can be changed so that the
exhaust air is discharged when exhaust pipe or hose communicating
with ports 38.
As distinguished from the embodiment of the invention shown in
FIGS. 1 through 5, in the embodiment of the invention shown in
FIGS. 8, 9, and 10, the air discharged through exhaust ports 14 of
motor cylinder 2 flows rearwardly through exhaust passages or
grooves b, with part of the exhaust air flowing into arcuate groove
33 and then rearwardly through retainer groove c. At the back
retainer 32, the air flowing through exhaust grooves or passages b
and that by-passed through retainer groove c flows into arcuate
passage or groove 36 and thence through discharge port 35 and
arrester 37 to be discharged through exhaust ports 38 in casing 1.
Thus, the retainer groove c serves as a by-pass exhaust passage,
and it is also possible to provide by-pass exhaust passages or
grooves in addition to retainer groove c.
In the embodiment of FIGS. 8, 9, and 10, the air discharged from
motor cylinder 2 flows rearwardly over the outer surface of the
cylinder, thus preventing overheating of the cylinder due to the
high speed rotation of rotor 3. Additionally, the arrester 37 is
very useful in preventing or reducing noise during operation.
With the present invention and with the inner surface of
cylindrical or tubular casing 1 formed with the longitudinal
grooves for air supply and exhaust, stop or retainer, and the like,
the supply and exhaust passages and the others are formed as parts
of the casing and are formed at the same time as the casing is
formed by extrusion. Thus, the air motor of the present invention
overcomes the shortcomings of conventional air motors in which the
cylinder is molded and formed with an extremely complicated
exterior surface. That is to say, that the present invention
enables both the casing 1 and the motor cylinder 2 to be
manufactured by mass production methods and produced at the lowest
cost.
As the air supply and the exhaust passages are shaped in the form
of grooves, the air under pressure flowing through these passages
flows quite smoothly with little resistance. As a result, the
driving force of the rotor can be greatly increased with a
corresponding great increase in the efficiency of the motor.
Moreover, as the interior of tubular casing 1 is divided into two
chambers, namely the front motor chamber and the rear air supply
and control chamber with the valve member 4, the air motor A can be
a little larger in size than the standard fountain pen. As the
control of the air flow, including fine adjustment of the air flow,
is effected by rotating the grip 18 or 18', the casing 1 can be
handled manually thus enabling elaborate grinding work to be
performed efficiently. The advantages in using the air motor of the
present invention cannot be over emphasized.
As the air supply and control chamber is provided with a filter
through which the compressed air flows through the air supply
passage, the motor cylinder 2 can be prevented from becoming filled
with dust, so that a high efficiency can be maintained for many
hours.
While specific embodiments of the invention have been shown and
described in detail to illustrate the application of the principles
of the invention, it will be understood that the invention may be
embodied otherwise without departing from such principles.
* * * * *