Abrading – Machine – Sandblast
Reexamination Certificate
2000-03-08
2001-08-21
Banks, Derris H. (Department: 3723)
Abrading
Machine
Sandblast
C451S090000, C433S088000
Reexamination Certificate
active
06277003
ABSTRACT:
TECHNICAL FIELD
This invention relates to gas abrasive technology. More particularly, it relates to methods and apparatus for supplying a gas stream of abrasive particles to abrade a surface and to control the flow of such a stream to the surface to be abraded. The invention is particularly useful for dental applications.
BACKGROUND
The use of gas abrasive in the dental industry has considerably reduced the pain and general unpleasantness involved in dental procedures. Traditional gas abrasive delivery systems worked much like a salt shaker. They were basically chambers which would be vibrated in order to force the abrasive out of the holes at the bottom of the chamber. Another type of gas abrasive delivery system vibrated the abrasive to flow up through a circular track to bring sand up through the top of the chamber. These systems had the common problem of excessive noise and vibration. Systems can be found which avoid the excessive noise and vibration by blowing gas over the top of the abrasive to create a dust cloud which could be blown or sucked out to the end piece. These systems had severe difficulty with abrasive flow control. The apparatus of this invention provides a gas abrasive delivery system having a more consistent flow pattern of the gas/abrasive stream. Also provided is a unique double-action pinch valve for controlling the flow of the gas/abrasive stream.
SUMMARY OF THE INVENTION
One aspect of this invention is an apparatus for dispensing a pressurized stream of gas having particles suspended therein, which apparatus comprises:
a container having a top portion and a bottom portion for holding the particles in a powder form;
a closure means for the container so that the container can be pressurized by a gas;
an interior chamber inside the container having at least one abrasive particle passage towards the bottom of the interior chamber through which the abrasive particles can enter the interior portion of the interior chamber;
a gas inlet line leading into the container;
an interior tube located inside the container having inlet and outlet ends and connected at its inlet end to the gas inlet line, the outlet end of the interior tube being directed downwardly into the interior of the interior chamber; and
an outlet passage leading from the interior of the interior chamber to the outside of the container.
Another aspect of this invention is a double acting pinch valve that comprises:
an unitary container;
gas inlet port leading into the container;
a pinch bar having a first contact side and a second contact side;
a first passage for a first flexible tube leading past the first contact side of the pinch bar;
a second passage for a second flexible tube leading past the second contact side of the pinch bar;
a tension means for retaining the pinch bar in a first position sufficient to pinch closed a first flexible tube in the first passage; and
an air pressure actuatable means within the container that, upon providing a pressurized gas to the gas inlet port, moves the pinch bar from the first position to a second position sufficient to open the first flexible tube in the first passage and pinch closed the second flexible tube in the second passage.
Yet another aspect of this invention is a double acting pinch valve comprising:
a unitary container;
a gas inlet port leading into the container;
a first, movable pinch bar having a first contact portion and a second contact portion;
a first passage for a first flexible tube leading past the first contact portion of the movable pinch bar;
a first pinch seat in contact with the second contact portion of the movable pinch bar;
a second, fixed pinch bar;
a second passage for a second flexible tube leading past the fixed pinch bar;
a second pinch seat juxtaposed to the fixed pinch bar such that the second flexible tube is positioned therebetween;
a translation means connected to the movable pinch bar;
a first tension means associated with the translation means for retaining the translation means in a first position sufficient to maintain the movable pinch bar to hold open the first flexible tube in the first passage,
a second tension means for maintaining the second pinch seat in a position sufficient to pinch closed the second flexible tube against the fixed pinch bar;
an air pressure actuatable means within the container that, upon providing a pressurized gas to the gas inlet port, moves the translation means from the first position to a second position sufficient to compel the movable pinch bar to pinch closed the first flexible tube in the first passage and to simultaneously compel the first pinch seat to contact the second pinch seat and open the second flexible tube in the second passage.
Another aspect of this invention is an apparatus for directing a pressurized stream of gas/abrasive particles against a surface, which apparatus comprises:
(a) a container having a top portion and a bottom portion for holding the particles in a powder form, the container having
a closure means for the container so that the container can be pressurized by a gas;
an interior chamber located inside the container having at least one abrasive particle passage towards the bottom of the interior chamber through which the abrasive particles can enter the interior portion of the interior chamber;
a gas inlet line leading into the container;
an interior tube located inside the container having inlet and outlet ends and connected at its inlet end to the gas inlet line, the outlet end of the interior tube being directed downwardly into the interior of the interior chamber; and
an outlet passage leading from the interior of the interior chamber to the outside of the container.
(b) a handpiece with a nozzle for directing a pressurized stream of gas/particles against a surface,
(c) a transmission tube connecting the handpiece and the outlet passage from the container, wherein the transmission tube has a valve between the outlet passage and the handpiece nozzle to regulate the flow of gas/particles stream therethrough, and
(d) a source of pressurized gas connected to the gas inlet line leading into the container.
Another aspect of this invention is a gas abrasive apparatus for directing a pressurized stream of gas/abrasive particles against a surface, which apparatus comprises:
(a) a source of a pressurized stream of abrasive particles suspended in a gas;
(b) a handpiece with a nozzle for directing the pressurized stream of gas-suspended particles against a surface;
(c) a first flexible transmission tube connecting the handpiece with the pressurized stream of gas-suspended particles;
(d) a double acting pinch valve that acts upon the first flexible transmission tube and that comprises:
a unitary container;
a gas inlet port leading into the container;
a first, movable pinch bar having a first contact portion and a second contact portion;
a first passage for the first flexible transmission tube leading past the first contact portion of the first pinch bar;
a first pinch seat in contact with the second contact portion of the first pinch bar;
a second, fixed pinch bar;
a second passage for a second flexible transmission tube leading past the second pinch bar;
a second pinch seat juxtaposed to the second pinch bar such that the second flexible tube is positioned therebetween;
a translation means connected to the first pinch bar;
a first tension means associated with the translation means for retaining the translation means in a first position sufficient to maintain the first pinch bar to hold open the first flexible tube in the first passage,
a second tension means for maintaining the second pinch seat in a position sufficient to pinch closed the second flexible tube against the second pinch bar;
an air pressure actuatable means within the container that, upon providing a pressurized gas to the gas inlet port, moves the translation means from the first position to a second position sufficient to compel the first pinch bar to pinch closed the first flexible tube in the first passage and to simultaneously compel the first pinch seat to contact the second pi
Blake Thomas S.
Bruns Craig R.
Fernwood Mark S.
Swihart Stephen L.
Banks Derris H.
Danville Engineering
Godward LLP Cooley
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