Prophy head

Details Prophy head Prophy head

2000-02-29

2001-11-13

Wilson, John J. (Department: 3732)

Dentistry

Apparatus

Having motor or means to transmit motion from motor to tool

C433S116000

Reexamination Certificate

active

06315559

ABSTRACT:

FIELD OF ART
This invention relates to a prophy head which is a head portion of a prophy handpiece for use in removing dental plaque, dental calculus, dental stains, and the like, settled on dental surfaces and interdental spaces, as well as in polishing dental surfaces and interdental spaces.
BACKGROUND OF THE INVENTION
A prophy handpiece equipped with a prophy head is for use in removing dental plaque, dental calculus, dental stains, and the like, settled on dental surfaces and interdental spaces, or in polishing dental surfaces after removal of dental calculus and the like by a scaler, or after patch-up of the dental surfaces or the like with a photo-polymerized resin.
FIG. 5
is a cross sectional view showing the construction of a conventional prophy head
50
, which is coupled to a sheath, not shown, having a motor accommodated therein. A housing section
51
of the prophy head
50
is formed of a head portion
51
a
and a mouthpiece
51
b
, and having a shaft (screw shaft)
52
therein. When it is used, a polishing brush
1
like one shown in
FIG. 1
is attached to the shaft
52
. In the thus formed prophy head
50
, a rotary output from the motor accommodated in the sheath is transmitted via driving force transmitting means consisting of a driving shaft
53
a
, a driving gear
53
b
, and an output shaft gear
53
c
, to the shaft
52
, and the thus transmitted output rotates the brush
1
with an abrasive applied thereto, to thereby carry out required polishing work. In place of the brush
1
, a rubber cup
2
like one shown in
FIG. 2
may be used.
When the prophy head is used, contaminants such as tooth debris, blood and/or saliva can easily enter the interior of the head portion
51
a
through a gap between the shaft
52
and the mouthpiece
51
b
. In other words, the gap can become a contaminant intrusion port. If the entered contaminants are allowed to accumulate therein, a bearing
54
and the gear
53
c
can be disadvantageously eroded. To cope with this disadvantage, an O-ring
55
is disposed on the periphery of the shaft in the head in order to close the gap.
However, the O-ring
55
seals the gap in a manner being in contact with the shaft
52
, and therefore driving of the shaft
52
can cause heat generation at the O-ring and wear-out of the same. In addition, a portion of the shaft
52
in contact with the O-ring
55
can wear as well. Therefore, the sealing performance of the O-ring can be deteriorated with the lapse of time, and further the durability of the O-ring and the shaft member can be damaged.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a prophy head which is capable of preventing intrusion of contaminants into a head portion thereof and includes a dust control mechanism which is good in durability, for preventing the intrusion of contaminants. The above and other objects of the present invention will become more apparent from the following description.
According to the present invention, there is provided a prophy head comprising a shaft for holding a polishing member, a bearing for supporting the shaft, housing means for retaining the bearing, driving-force transmitting means for transmitting driving force to the shaft to rotate the shaft, and rotary dust control means rotating integrally with the shaft for preventing intrusion of contaminants through a gap between an inner surface of a lower end of the housing means and an outer periphery of the shaft,
wherein said rotary dust control means has a surface extending radially outwardly from said outer periphery of the shaft and placed downwardly beyond said lower end of the housing means, and a surface placed in close proximity with said inner surface of the lower end of the housing means.
The prophy head according to the present invention has the rotary dust control means rotating integrally with the shaft, for preventing intrusion of contaminants into the head portion through the gap between the outer periphery of the shaft for rotating the polishing member and the inner surface of the lower end of the housing means including a mouthpiece or the like.
The rotary dust control means has a surface which extends radially outwardly from the outer periphery of the shaft and is placed downwardly beyond the lower end of the housing means, and a which is placed in close proximity with the inner surface of the lower end of the housing means. The surface of the rotary dust control means which is placed in close proximity with the inner surface of the lower end of the housing means is out of contact therewith.
The rotary dust control means constructed as above rotates integrally with the shaft, to thereby blow away contaminants in a radially outward direction of the shaft, more specifically in a tangential direction of the shaft. Therefore, the intrusion of contaminants through the contaminant intrusion port into the head portion can be prevented. Downward protrusion of the rotary dust control means to place its surface downwardly beyond the lower end of the housing means may assume a very small length insofar as the blown contaminants can be prevented from directing toward and entering the intrusion port. In addition, the rotary dust control means may be formed separately from the shaft, or formed integrally with the shaft by allowing part of the shaft to protrude radially outwardly from the same.
The rotary dust control means may be designed to have a collar portion, of which surface define an extension of the radially extending surface placed downwardly beyond the lower end of the housing means, so that a surface of the collar portion further extends radially outwardly to cover at least partly the lower end of the housing means. In this design, the contaminant intrusion port is covered with the collar portion in a manner being out of contact therewith. As a result, the intrusion of contaminants can be prevented more effectively, and a contaminant blowing effect can be more enhanced by centrifugal force of the collar portion.
The polishing member generally includes a polishing brush, a rubber cup, or the like. The prophy heads are broadly divided into a screw type in which the polishing brush is screwed into the shaft, and a knob type in which the rubber cup is installed on the knob portion of the shaft in a manner covering the same.
The bearing is usually a metal bearing, but it may be a ball bearing as well. The housing means includes the mouthpiece which is detachably connected to the lower end of the head portion.
According to the present invention, the prophy head may optionally has an additional stationary dust control means for further preventing intrusion of contaminants into the head portion so that a space of a depression defined by the rotary dust control means, the shaft, and the bearing is almost filled with the stationary dust control means without contacting with the surfaces of the rotary dust control means and the shaft defining the space. The stationary dust control means may be fixed to the lower portion of the bearing. It may be formed of a separate member and attached to the bearing, or alternatively formed by allowing part of the bearing to protrude downwardly.


REFERENCES:
patent: 2791835 (1957-05-01), Staunt
patent: 5642995 (1997-07-01), Bailey
patent: 5676542 (1997-10-01), Lingenhole et al.
patent: 54-69699 (1979-05-01), None
patent: 8-66411 (1996-03-01), None

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