U.S. patent number 3,631,631 [Application Number 05/004,533] was granted by the patent office on 1972-01-04 for pneumatic abrasive cutting apparatus.
This patent grant is currently assigned to Dental Gold Company. Invention is credited to Jean I. Greenstein.
United States Patent |
3,631,631 |
Greenstein |
January 4, 1972 |
PNEUMATIC ABRASIVE CUTTING APPARATUS
Abstract
An apparatus which utilizes a stream of gas to propel fine
particles which is particularly useful in the manufacturing of
dental restorations for functions such as cutting, cleaning and
polishing, is disclosed. An abrasive powder is forced from a
container by a stream of gas which first passes through the powder.
The gas, after passing through the powder, flows through a tube
disposed in the powder and then to a nozzle. An orifice disposed
through the wall of the tube provides an even and continuous
injection of powder into the stream of gas.
Inventors: |
Greenstein; Jean I. (Encino,
CA) |
Assignee: |
Dental Gold Company (Los
Angeles, CA)
|
Family
ID: |
21711250 |
Appl.
No.: |
05/004,533 |
Filed: |
January 21, 1970 |
Current U.S.
Class: |
451/90;
451/99 |
Current CPC
Class: |
B24C
7/0046 (20130101); B24C 7/0053 (20130101) |
Current International
Class: |
B24C
7/00 (20060101); B24c 003/06 () |
Field of
Search: |
;51/8,12 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Swingle; Lester M.
Claims
I claim:
1. A pneumatic abrasive cutting apparatus comprising:
a closed vessel having a lower end and an upper end, adaptable for
containing an abrasive;
a source of gas under pressure;
a check valve interconnecting said lower end of said vessel and
said source of gas such that gas may flow into said vessel;
a tube mounted in said vessel from said upper end of said vessel to
said lower end of said vessel, said tube having at least one
orifice disposed through its wall; and
a nozzle, coupled to the end of said tube disposed at said lower
end of said vessel;
whereby abrasive from said vessel is drawn into said orifice by the
flow of gas through said tube and is delivered to said nozzle under
pressure.
2. The pneumatic abrasive cutting apparatus defined in claim 1
wherein said orifice is disposed through the wall of said tube near
the lower end of said vessel.
3. The pneumatic abrasive cutting apparatus defined in claim 2
wherein a regulator, to regulate the flow of gas, is interconnected
between said source of gas and said check valve.
4. The pneumatic abrasive cutting apparatus defined in claim 3
wherein said vessel is connected to vibration means, for vibrating
an abrasive in said vessel.
5. The pneumatic abrasive cutting apparatus defined in claim 4
wherein said vessel contains a manually removable top which
sealingly engages said vessel to allow said vessel to be readily
loaded with abrasive.
6. A pneumatic abrasive cutting apparatus comprising:
a base;
a platform movably coupled to said base;
a first and second closed vessel, each having a lower end and an
upper end for containing an abrasive, both mounted on said
platform;
a source of gas under pressure;
regulator means, for regulating the flow of gas from said source of
gas, connected to said source;
a first check valve connected to the lower end of said first
vessel, for allowing gas to flow into said vessel;
a second check valve connected to the lower end of said second
vessel, for allowing gas to flow into said vessel;
a first tube mounted in said first vessel from said upper end of
said vessel to said lower end of said vessel, said tube having at
least one orifice disposed through its wall;
a second tube mounted in said second vessel from said upper end of
said vessel to said lower end of said vessel, said tube having at
least one orifice disposed through its wall;
a first valve interconnecting said regulator with said first check
valve;
a second valve interconnecting said regulator with said second
check valve;
control means for selectively opening and closing said first and
second valve;
a first nozzle, coupled to the end of said first tube disposed at
said lower end of said first vessel;
a second nozzle, coupled to the end of said second tube disposed at
said lower end of said second vessel; and,
a vibrator, coupled to said platform for vibrating the contents of
said first and second vessels;
whereby material from said first and second vessels may be
selectively delivered to said first and second nozzles.
7. The pneumatic abrasive cutting apparatus defined in claim 6
including a foot control for allowing gas to flow from said vessels
to said nozzles.
8. The pneumatic abrasive cutting apparatus defined in claim 6
wherein said orifice in said first and second tubes is disposed
near the bottom of said first and second vessels.
9. In a pneumatic cutting apparatus utilizing a source of gas under
pressure to force an abrasive from a closed container, the
improvement comprising:
a check valve interconnecting said source of gas with the bottom of
said container, adaptable for allowing gas to flow into said
container; and
a tube disposed from the upper end of said container to the lower
end of said container, said tube having at least one orifice
disposed through its wall, near the bottom of said container;
whereby a line coupled to said lower end of said tube receives a
flow of gas containing said abrasive.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the field of pneumatic abrasive devices,
particularly those utilized in the dental field.
2. Prior Art
Numerous devices have been disclosed in the prior art which utilize
a stream of gas to propel an abrasive powder. These types of
devices have been used in dentistry for polishing, cleaning and
cutting dental restorations. One such device is disclosed in U. S.
L. Pat. No. 3,084,484.
One of the principal problems with the prior art devices is that
they do not provide a continuous, constant flow of powder.
Typically, these devices become clogged and do not provide an even
flow of powder in the stream of gas.
SUMMARY OF THE INVENTION
A pneumatic apparatus which utilizes a continuous stream of gas to
propel fine particles is described. The fine particles which are
typically an abrasive powder are forced from a container or vessel
by the stream of gas. A tube which is coupled to a nozzle is
disposed in the powder such that its upper end is above the level
of powder in the vessel. An orifice is disposed through the wall of
the tube near the bottom of the vessel. A stream of gas is injected
into the lower end of the vessel through a check valve; this gas
flows through the powder in the vessel and then into the upper end
of the tube. As the gas flows through the tube, it causes powder in
the vessel to be drawn into the stream of gas and to be
subsequently delivered to the nozzle. The vessel is mounted on a
platform and subjected to vibrations which agitate the powder in
the vessel and assist in preventing the device from becoming
clogged.
BRIEF DESCRIPTION OF THE DRAWING
The drawing illustrates in schematic form a pneumatic abrasive
dental apparatus wherein the apparatus utilizes two vessels which
are both illustrated in a cross-sectional view.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawing, an abrasive powder or the like is stored
containers or vessels 10 and 14 and is pneumatically pumped to
nozzles 53 and 52, respectively. The vessels 10 and 14 may be
ordinary metal vessels which are adaptable for sealingly containing
a powderlike substance. Lid 11 threadingly engages vessel 10. An
O-ring 12 which is disposed about an upper edge of vessel 10,
between the vessel and lid, assures that the vessel is sealed and
adaptable for being slightly pressurized. Likewise, vessel 14 has a
lid 15 which threadingly engages vessel 14 and sealingly engages
vessel 14 by means of O-ring 16. While in the drawing, both vessels
10 and 14 are illustrated as generally cylindrical members, they
may in fact have any shape provided that they have an upper and
lower end in which the tubes 18 and 20 may be disposed.
Vessel 10 contains a cylindrical tube 18 which is disposed from the
upper end of the vessel to the lower end of the vessel. A small
orifice 21 is disposed through the wall of tube 18, near the bottom
of vessel 10, thus allowing material 24 to flow from the interior
of the vessel to the interior of tube 18. While in the present
embodiment only a single orifice 21 is illustrated, a plurality of
orifices may be utilized. Likewise, a tube 20 is disposed from the
upper end of vessel 14 to the lower end of that vessel, and an
orifice 23 is disposed through the wall of tube 20 near the lower
end of vessel 14. The vessels 10 and 14 and the tubes 18 and 20 may
be ordinary metal parts manufactured utilizing commonly known
techniques. The tubes 18 and 20 in the presently preferred
embodiment of the invention have an inside diameter of
approximately one-eighth inch.
The lower end of tube 18 is coupled to flexible tube 48 via line
46; the lower end of tube 20 is coupled to flexible tube 49 through
line 47. The tubes 48 and 49 are coupled to nozzles 52 and 53,
respectively. The nozzles 52 and 53 may be any commonly known
nozzle adaptable for handling a stream of gas containing a fine
powder. A handpiece 50 is coupled to nozzle 52 in order that that
nozzle may be readily manually utilized. Likewise, a handpiece 51
is coupled to nozzle 53. The lines 46 and 47, flexible lines 48 and
49, and the nozzles 52 and 53 may be ordinary parts, which are
commercially available.
A pinch valve 60 is disposed across both lines 48 and 49 and
prevents the passage of gas through these lines, unless the valve
is actuated, by pinching the flexible lines. Valve 60 may be an
electrically or pneumatically operated valve or valves similar to
valves 42 and 40 and may be used in place of valve 60.
Line 37 is coupled to a source of gas under pressure. The source of
gas may be any one of numerous commercially available gas sources
such as those produced by a pump or hose which are provided from a
storage tank. The gas which is provided to line 37 under pressure
may be carbon dioxide, nitrogen or similar inert gases. Air may
also be utilized in the present application. The gas applied to
line 37 should be dry and substantially free of moisture. In the
presently preferred embodiment, gas at a pressure of 80-90 p.s.i.
has been found to be satisfactory for the operation of the
apparatus. Regulator 38 which is coupled to line 37, may be any
ordinary regulator adaptable for regulating and adjusting the flow
of gas. The gas flowing through regulator 38 is adjustable by means
of knob 39. The output from regulator 38 is coupled to T-coupler 54
and the output from coupler 54 is coupled to valves 40 and 42.
Valves 40 and 42 may be ordinary valves which selectively allow or
prevent the passage of gas. In the preferred embodiment of the
present invention, valves 40 and 42 are electrically operated
valves.
Switch 61, an ordinary electrical switch, is coupled to valve 42 by
lead 43 and to valve 40 by lead 41. Switch 61 provides a means for
selectively opening either valve 40 or 42 and hence allowing gas to
flow into either vessel 10 or 14, as indicated by the left (L) and
right (R) position on switch 61.
The output from valve 42 is coupled to the lower end of a vessel 14
via line 55 and check valve 36. The output from valve 40 is coupled
to the lower end of vessel 10 via line 56 and check valve 34. Check
valves 34 and 36 may be ordinary check valves which allow a stream
of gas to pass in only one direction. Valves 34 and 36 allow gas
from valves 40 and 42, respectively, to flow into vessels 10 and
14, respectively, but prevent gas or other materials from flowing
out of the vessels into lines 55 and 56. Valves 34, 36, 40 and 42,
lines 55 and 56, T-coupler 54, and regulator 38 may be ordinary
parts which are commercially available.
Foot control 45 which is coupled to valve 60 via line 62 and
provides a means for opening pinch valve 60, may be an ordinary
foot control commonly known in the prior art. In the presently
preferred embodiment, valve 60 is a pneumatically operated valve
and is actuated with gas from line 37; foot control 45 provides a
means for controlling the flow of gas to valve 60.
Vessels 10 and 14 are rigidly coupled to platform 26 and platform
26 is coupled to base 29 via springs 30. Thus, platform 26 is able
to vibrate relative to the base 29. A vibrating means 32 is coupled
to platform 26 and is adaptable for vibrating platform 26, thus
causing the contents within vessels 10 and 14 to be agitated.
Vibrating means 32 may be a commercially available electrically
operated vibrator or may be a pneumatically operated vibration
means which is operated from the source of gas under pressure
supplied to line 37.
While in the presently preferred embodiment of the present
invention only a single regulator means 38 is illustrated coupled
to line 37, it is within the scope of the present invention to
utilize two regulator means. For example, one regulator means could
be coupled into line 55 and the other into line 56. This would
allow the gas flowing into each of the vessels 10 and 14 to have a
separate flow control.
In the presently preferred embodiment, two vessels 10 and 14 are
utilized. Each of these vessels in this embodiment are utilized to
contain a different material. It is of course within the scope of
the present invention to utilize a single vessel or a greater
number of vessels on a single platform. Also, any number of vessels
may be coupled to a single nozzle by utilizing T-connectors and
additional valves.
In order to utilize the disclosed apparatus, an abrasive material
is placed in either or both of the vessels 10 and 14 by removing
lids 11 and 15, respectively. Any type of fine abrasive powder may
be utilized; for example, aluminum oxide, glass shot, sand,
sapphire dust, or similar material may be placed within these
vessels. The vessels should be filled such that the level of
material placed within the vessel is below the upper end of the
tubes 18 and 20 as is illustrated in the drawings. After an
abrasive material is placed within the vessel, the lids are
tightened onto the vessels to seal the vessels.
Assume that a source of gas has been applied to line 37 and that
valve 40 is opened and also that foot control 45 is depressed,
opening pinch valve 60, gas will flow through line 56 and check
valve 34 into material 24 illustrated within vessel 10. The gas
flows through the material 24, causing the material to be somewhat
loosened and agitated, and then flows into tube 18 as is
illustrated by flow lines 57. This occurs since the ambient
pressure at nozzle 53 is less than the pressure of the gas applied
to vessel 10. As the gas flows downward in tube 18, it causes
material 24 to be drawn into orifice 21 and injected into the
stream of gas. It has been found that by utilizing a tube such as
tube 18, and an orifice 21, and by passing the gas through the
material 24 before it enters the upper end of the tube 18, a
continuous and even flow of material 24 is injected into the stream
of gas. Additionally, the vibrator 32 which is operated during this
time, causing the materials 24 and 25 in vessels 10 and 14,
respectively, to vibrate, assists the flow of the materials 24 and
25 into the stream of gas.
To utilize the apparatus, the nozzles 52 and 53 may be held
manually in the proximity of a workpiece and the stream of gas
containing the abrasive material when contacting the workpiece
cuts, polishes, or removes materials, depending on the type of
abrasive used and the hardness of the workpiece. Different types of
abrasives may be placed within vessels 10 and 14 so that the
apparatus may be utilized to perform different functions; for
example, an abrasive adaptable for cutting may be placed within
vessel 10 and an abrasive adaptable for polishing may be placed
within vessel 14. The selection of the material placed within the
vessels 10 or 14 is of course made by switch 61 which will
alternately allow gas applied to line 37 to flow either into vessel
10 or vessel 14, and cause either material 24 or material 25 to be
delivered to the nozzles. The rate at which the gas flows through
the apparatus and hence, the rate at which the abrasive material
within the vessels is delivered to a nozzle, may be readily
controlled by knob 39 of regulator 38.
The apparatus is particularly useful in dental laboratories for
such applications as the manufacturing of dental restorations where
there is a requirement to remove, cut, or polish hard materials
such as ceramic, steel, copper, brass, gold platinum, glass and
similar materials. Some typical applications to which the apparatus
may be utilized in the dental industry are carving porcelain,
rolling fossa, removing porcelain, removing surface oxide and
polishing.
* * * * *