Dentistry – Apparatus – Having motor or means to transmit motion from motor to tool
Reexamination Certificate
1999-04-15
2001-03-20
Wilson, John J. (Department: 3732)
Dentistry
Apparatus
Having motor or means to transmit motion from motor to tool
C433S126000
Reexamination Certificate
active
06203322
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a dental appliance and, more specifically, to a dental prophylaxis angle (commonly called a “prophy angle”).
Dental prophy angles typically include a hollow head on the end of a tubular body. One such angle is disclosed in Kraenzle U.S. Pat. No. Re 34,997. A drive shaft within the body drives a rotor in the head of the angle. At the rearward end of the angle, i.e., the end remote from the head, the drive shaft is driven by a drive mechanism. A prophylaxis cup (“prophy cup”) is attached to the rotor. These angles are commonly constructed of lightweight, inexpensive plastic so that they are disposable and may be discarded after use, thus obviating the expense and inconvenience of sterilization. Inexpensive plastic materials do not lend themselves easily to use in connection with an angle which is sturdy and easily assembled and which operates smoothly and consistently. Designers of plastic prophy angles are continuously trying to improve such angles to make them more sturdy, operate more smoothly, operate with less friction, and to improve efficacy for cleaning and polishing teeth.
SUMMARY OF THE INVENTION
It is an object of this invention, therefore, to provide an improved dental appliance, more particularly, to provide an improved prophylaxis angle which is economical to manufacture, easily assembled, of sturdy construction, pleasing in appearance, and which operates smoothly and consistently.
Briefly, therefore, the invention is directed to a dental prophy angle having a forwardly opening forward end formation with a closure therefor which overlap each other when the closure is applied to the end formation, and cooperative locking elements for securing the closure in fixed position on the forward end formation.
In another aspect the invention is directed to a dental prophy angle having a closure and a forwardly opening end formation and a sealing rim for sealing the mating interface between the closure and the end formation.
The invention is also directed to a dental prophy angle having a cylindric bearing surface for a rotor, which surface has at least two bearing discontinuities therein formed by mating surfaces of a closure and a recessed end formation. The bearing discontinuities are engageable by a rotor ridge on the rotor upon rotation of the rotor, and the mating surfaces lie in planes which extend non-radially with respect to the rotor.
The invention is further directed to a dental prophy angle having a rotor bearing and a drive shaft bearing, one of which has a juncture discontinuity thereon formed by mating components of the angle. The juncture discontinuity has a segment which is not parallel to a longitudinal axis of the rotor bearing or drive shaft bearing on which lies the juncture discontinuity.
In another aspect the invention is directed to a dental prophy angle having a cylindric bearing surface for the rotor having a juncture discontinuity thereon formed by mating surfaces of a closure and a recessed end formation. The juncture discontinuity has a segment which is not parallel to the axis of the rotor.
The invention is further directed to a dental prophy angle having a drive shaft having a longitudinal axis, first and second opposite ends, and a first section on one side of a plane extending through the shaft generally transverse to the longitudinal axis. The first section extends from the plane to the first end of the shaft, and there is a second section on an opposite side of the plane extending from the plane to the second end of the shaft. The first section of the shaft has an outside diameter which does not substantially increase along the first section in a direction from the plane to the first end and the second section of the shaft has an outside diameter which does not substantially increase along the second section in a direction from the plane to the second end. As such, the shaft may be formed as an integral molded part in a mold having a parting line corresponding to the plane, the drive shaft being configured for insertion, rear end first, into the bore from the forward end of the tubular extension.
Still further, the invention is directed to a dental prophy angle having a drive shaft having an elongate shape and a longitudinal axis extending through a bore in the angle, which drive shaft is inserted into said bore, rear end first, from the forward end of the tubular extension, and which drive shaft is a molded piece having a mold parting line extending circumferentially of the shaft and not longitudinally of the shaft.
The invention is also directed to a dental prophy angle having a rotor rotary in a chamber on an axis transverse to the axis of a bore in the angle, the rotor having a driven gear with gear teeth adapted for engagement with the gear teeth of said drive gear. The rotor has a generally vertical cylindric section extending generally parallel to the rotor axis, the cylindric section being sized for engagement by the forward end of the drive shaft over a substantial area thereof to limit the forward movement of the drive shaft toward the rotor and thus limit the forward force applied to the driven gear by the driving gear.
In another aspect the invention is directed to a dental prophy angle having a rotor rotary in a chamber on an axis transverse to the axis of a bore in the angle, with the rotor having a driven gear with gear teeth adapted for engagement with gear teeth of a drive gear, and the rotor having a generally vertical cylindric section extending below the driven gear and generally parallel to the rotor axis. The cylindric section is sized for engagement by the forward end of the drive shaft over a substantial area thereof to limit the forward movement of the drive shaft toward the rotor and thus limit the forward force applied to the driven gear by the driving gear.
The invention is further directed to a dental prophy angle having a drive shaft having a longitudinal axis, first and second opposite ends, and a first section on one side of a plane extending through the shaft generally transverse to the longitudinal axis. The first section extends from the plane to said first end of the shaft, and a second section on an opposite side of the plane extends from the plane to the second end of the shaft. The first section of the shaft has an outside diameter which does not substantially increase along the first section in a direction from the plane to the first end and the second section of the shaft has an outside diameter which does not substantially increase along the second section in a direction from the plane to the second end. As such, the shaft may be formed as an integral molded part in a mold having a parting line corresponding to said plane. The drive shaft also has two spaced-apart shaft bearing surfaces which contact two spaced-apart bore bearing surfaces inside the tubular extension.
In another aspect the invention is directed to a dental prophy angle having an elongate one-piece hollow body of molded plastic material comprising a tubular handle and a tubular extension extending from the handle at one end thereof. There is a gate imperfection on an external surface of the elongate hollow body which is covered over and hidden from view upon securement of the rotor and drive shaft in place, the gate imperfection being remote from bearing surfaces for the rotor and the drive shaft.
Other objects and features of the invention will be in part apparent and in part pointed out hereinafter.
REFERENCES:
patent: Re. 34997 (1995-07-01), Kraenzle
patent: 144744 (1873-11-01), Cottrell
patent: 170178 (1875-11-01), Locke
patent: 186471 (1877-01-01), Gilbert
patent: 186504 (1877-01-01), Starr
patent: 207079 (1878-08-01), Starr
patent: 301936 (1884-07-01), Swasey
patent: 307686 (1884-11-01), Starr
patent: 319110 (1885-06-01), Miller
patent: 341925 (1886-05-01), Lemassena
patent: 361806 (1887-04-01), Ballard
patent: 362808 (1887-05-01), Wood
patent: 387581 (1888-08-01), Custer
patent: 391302 (1888-10-01), Deane
patent: 409837 (1889-08-01), Hardie
patent: 425897 (1890-04-01), Mo
Bumgarner Melba
Senniger Powers Leavitt & Roedel
Wilson John J.
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