Zero-suckback device for disposable high-speed turbine dental drill handpiece
View Patent ↗A zero-suckback device for a disposable high-speed turbine dental drill handpiece includes two units respectively installed at two ends of the head of the handpiece. On one side of the handpiece head where a drill pin is installed, one unit consists of an elastic shaft sealing casing which is centrally embedded with a central framework made of hard substances and a non-elastic shaft sealing casing, and a lip portion of the elastic shaft sealing casing fits a wind wheel shaft with a tapered end. On the cover side of the handpiece head and between a button housing and a head housing, an O-shaped sealing ring is installed, and a one-way ball valve is installed at the center of the button housing. Suckback prevention measures are adopted at both sides of the handpiece head, so matters sucked back can be controlled to be a very low level, nearly zero.
1. A handpiece head comprising a zero-suckback device for a disposable high-speed turbine dental drill handpiece, the zero-suckback device jointly comprising;
a first suckback prevention device installed on a side of the handpiece head equipped with a drill pin; and
a second suckback prevention device installed on a side of the handpiece head equipped with a head cover,
wherein the head cover comprises a head housing and a button housing; a power wind wheel and a wind wheel shaft which drive the drill pin to rotate are disposed in a space formed by fastening the handpiece head and the head cover; the wind wheel shaft is supported by two bearings; O-shaped rubber damping rings are disposed between the bearings and the handpiece head; the wind wheel shaft is provided with the head cover at the upper end; a neck of the head is provided with a water duct, an air intake passage and an air exhaust passage; and an opening of the air intake passage is positioned at the power wind wheel;
wherein the second suckback prevention device comprises an annular clamping slot disposed between the head housing and the button housing and positioned on an inner side of the head housing, the clamping slot internally embedded with an O-shaped sealing ring; and a one-way air exhaust mechanism provided in the button housing;
wherein the O-shaped sealing ring and the one-way air exhaust mechanism together prevent contaminants from entering into the button housing;
wherein the wind wheel shaft disposed in the handpiece head has one end connected to the drill pin while the end is a conical brake face, a lower end of the wind wheel shaft is retractably disposed in the handpiece head;
wherein the first suckback prevention device comprises an elastic shaft sealing casing and a non-elastic shaft sealing casing on an end face connected to one side of the drill pin, the elastic shaft sealing casing is centrally formed with a drill pin hole with a size which is a little greater than a size of an outer diameter of the drill pin, an outer edge of the non-elastic shaft sealing casing is in connected with an outer edge of the handpiece head through screw threads, the non-elastic shift sealing cover is centrally formed with a drill pin hole with a size which is a little greater than the size of the outer diameter of the drill pin;
wherein a thickness of the elastic shaft sealing casing close to a central portion is greater than a thickness of a ring-shaped portion between the central portion and the edge of the elastic shaft sealing casing, an inner surface of the central portion of the elastic shaft sealing casing is a tapered face matched with a brake surface of the wind wheel shaft; and
wherein the elastic shaft sealing casing is disposed in the non-elastic shaft sealing casing, and a shape of the inner wall of the non-elastic shaft sealing casing is matched with the exterior shaft of the elastic shaft sealing casing in the inflated state.
2. The handpiece head according to claim 1 , wherein the handpiece head and the head cover are made of metal or rubber plastic materials.
3. The handpiece head according to claim 1 , wherein the elastic shaft sealing casing is made of rubber or rubber plastics.
4. The handpiece head according to claim 1 , wherein the non-elastic shaft sealing casing is made of metal or hard plastic materials.
5. The handpiece head according to claim 1 , wherein the O-shaped sealing ring between the head housing and the button housing is made of rubber, plastic or rubber plastic materials.
6. The handpiece head according to claim 1 , wherein the one-way air exhaust mechanism is a one-way ball valve, comprising vent holes which are formed in a center of the button housing and a valve body which is disposed on the button housing, positioned in the dental drill handpiece and corresponds to the vent hole; the valve body contains a valve ball inside; and an exhaust opening is formed at the lower end of the valve body and communicates with an interior of the dental drill handpiece.
7. The handpiece head according to claim 6 , wherein a quantity of the vent holes is 2-8.
8. The handpiece head according to claim 7 , wherein the quantity of the vent holes is 4.
9. The handpiece head according to claim 6 , wherein the valve body is a copper or stainless steel product.
10. The handpiece head according to claim 6 , wherein the valve ball is a metal or rubber plastic product.
11. The handpiece head according to claim 1 , wherein on one side of the non-elastic shaft sealing casing, the elastic shaft sealing casing is internally embedded with a hard central framework.
12. The handpiece head according to claim 11 , wherein the outer diameter of the hard central framework is a little smaller than that of the central portion of the elastic shaft sealing casing, and the size of the inner diameter is a little greater than the size of the outer diameter of the drill pin.
13. The handpiece head according to claim 11 , wherein the hard central framework is made of metals, hard rubber plastics or hard plastics.
14. The handpiece head according to claim 11 , wherein the hard central framework is a metal ring.