US2924012A

US2924012A - Dental handpiece

Info

Publication number: US2924012A
Authority: US
Publication date: 1960-02-09
Anticipated expiration: 1977-02-09

Description

United States Patent DENTAL HANDPIECE Charles A. Ellis, Rochester, N.Y., assgnor to Ritter Company, Inc., Rochester, N.Y., a corporation of Delaware Application January 9, 1958, SerialNo. 707,964

3 Claims. (Cl. 32--27) This invention relates to dental handpieces, andmore particularly to a dental handpiece having an adjustable head, one object being the provision ofk a moresatisfactory handpiece of this nature.

Dental handpieces generally comprisea cylindrical body portion adapted :to be held by the dentist, a means for holding ayburr or other dental tool, and meansfor imparting-rotary motion to the dentaltool. In the case of. handpieces having self-contained source of power such as the air turbine driven handpiece described in the.y Charles A. Ellis application for patent on Dental Handpiece Drive Mechanism, Serial No. 680,454, led August27, 1957, the air driven turbine or other source of power is con: tained within the grip portion of the handpiece and transfers rotary motion directly to the tool. However, ithas been found ythat it is often desirable to adjust theangle between the gripping portion of the handpiece,A andv the tool so as to enable the operator to conveniently Work on certain portions of the patients teeth. It is therefore desirable to have a dental handpiece containingaprovision for varying the angle between the gripping.v portion and the tool and the provision of such a. handpiece, is an object of this invention.

Provision of a handpiece having means forvaryingthe angle of the gripping portion and the-tool must contain a provision for the transmission of power through this varying angle and the provision of such transmission means is another object; of this invention. Other objects of this invention include the provision of a dental handpiece of the above description which'is relatively simple, Positive in operation and easy to maintain.

Other objects and advantages of my inventiorrzwill be particularly set forth in the claims and will be apparent from the following description, when taken in connection with the accompanying drawings, in which:

Fig. 1 is a bottom plan view of a dental handpiece embodying this invention;

Fig. 2 is a cross-sectional View of the handpiece of Fig. 1 taken substantially along lines 2-2 in the direction of the arrows;

Fig. 3 is a cross-sectional view taken substantially along lines 3 3 of Fig. 1 in the direction of the arrows;

Fig. 4 is a cross-sectional view taken substantially along lines 4 4 of Fig. 2 in the direction of the arrows; and

Fig. 5 is a fragmentary side elevational View, partially cut away, of a dental handpiece embodying this invention.

A dental handpiece embodying the present invention for the reception of a dental tool, and transmission means for transferring the rotary motion of said turbine means -to said ltool holding means.

Referring now to the drawings, 10 is a casing which is :shown as being of substantially cylindrical shape but which 2, may be tapered and serrated as: i`s Well, known inthe art for providing a convenient and'. comfortable gripping surface. A block 1-2 (Fig. 2.)A containing, theturbine. drive elements. is mounted in casing 10. Block. 12 contains a cavity 14-which is adapted toM contain a turbine. rotor 16 on a shaft 17 rotatably mounted in bearingsv 18- in line with the longitudinal axis of casing10'.

Suitable passageways

20 and 22 are provided in block 12 for the ow of air to and from turbine rotor. 16. An` air line4 24which communicates with.A a. suitable source of. compressed air (not shown) is connected to-passage. 20 for providinga source of air to drive. turbine, 16. An eccentric stud. 24 is mounted on and extends forwardly from the frontend of shaft 17 of turbine 16 for. purposes hereinafter to be described. StudZA ispreferably. an. integral part of shaft 17, but it may be separately madeand fastenedl tothe shaft.

A removable inner casing-2.6 (Fig,` 2) is inserted in the fore part of casing 10. Casing 26'contains. mechanism hereinafter described, for transmittingthe motion of turbine 16to. a dental burr. orother tool.. Casing26 and its. associated mechanism is. removable from outer casing 10 as a unit, so thatvarious transmission means and head mechanism may. besubstitutedfor the one to.. be shown. I

The power transmission mechanism in casing 26 comprises an internally toothedcringgear 28. mounted on the interior surface of the casingas` shownin Fig. 2, meshing with a pinion gear 30. GearA 30.is. bored. to receive a bearing32. on stud.24. A4v forwardly extending shaft.34 forms anintegral part ofpiniongear. 30. The forward end of shaft. 34 is .supported in. a. ball bearing36.(Fig..2) mounted on the interior.- of. afplugSSr-which. closesthe forward end of inner. case.26. Whenrturbinel rotates, eccentric stud24 movespinion gear tlinacircular path, and pinion 30` rolls aroundfon. the interior teeth of xed ring gear` 28, thus imparting,thecombinationvof.a rotary and a rocking motionto shaft34. Bearing 36 is-loose enough to. rotationally` supportA shaftk 34k and Vallow this limited rocking motion. A pinion gear35is mountedon the frontend of shaft 34. Pinion gear. 35T may either be formedgas an integral parttof. shaftv 34,-or itmay be separately made and fastened. I to the1shaft, if desired.

The. casing holdingthe dental tool comprises a sube stantially cylindricalshell. mounted on. a saddle-'shaped block .38. Block 38.carries apair.of.outwardlyextending threaded trunnions or studs 40 which engage a pair of forwardly extending triangular shaped ears 42 (Figs. 1 and 5) forming integral portions of casing 10. Ears 42 are clamped against block 38 by means of a pair of ad justing nuts 44 threadedly engaging studs 40. The outer surface of block 38 and the inner surfaces of ears 42 may be serrated in a circular pattern as indicated at 46 in Fig. 5, so that when nuts 44 are drawn tight to force ears 42 against block 46, the latter parts are `securely locked against rotation.

A shaft 4S is mounted in casing or shell 36 on a pair of bearings 5t) and 52 as shown in Fig. 2. The lower end of shaft 48 contains a tapered hole 54 for the reception of the shank of a burr or other dental -tool 56. A crown gear 53 is rigidly mounted on shaft 48 with its teeth in engagement with gear 35 on the end of shaft 34. Thus, rotary motion is transferred from shaft 34 through gear 35 to gear 5S, which in turn causes rotation of shaft 48, driving dental tool 56.

It will be appreciated that since eccentric 24 imparts a rocking motion to gear 30, gear 35 will also have a limited rocking as well as a rotary motion. However, since bearing 36 is relatively nearer to gear 35 than it is to gear 30, this rocking motion of gear 35 will be relatively small. Suiicient clearance is allowed between the teeth and gear 35 and crown' gear 58 so that this rocking motion does not interfere with the functioning of these parts. In any case, since shaft 48 is held by

bearings

50 and 52, the rocking motion of shaft 34 does not interfere with the alignment thereof. l

Studs 40 on block 38 are carefully positioned so that they are in line with the pitch line of crown gear 58. Thus, when casing 36 is adjusted by rotating the same about studs 40, the relation between

gears

35 and 58 is not disturbed. The edges of the teeth of crown gear 58 are slightly beveled so that the change in angle between gear 58 and gear 35 does not interfere with the transmission of power between these two gears. Thus, the rotary motion imparted to shaft 34vby means of eccentric 2'4 is transmitted through gear 35 to crown gear 58 irrespective of the angle at which shaft 4S is adjusted with respect to casing 10. For this reason, angle of dental tool 56 may be adjusted relative to casing 10 so that the dentist may work at the most convenient angle for the job being carried out.

, It will be appreciated that under certain circumstances, that the dentist may wish to have a straight handpiece, that is, a handpiece having the tool substantially in line with the axis of casing 10. Should this be the case, inner casing 26 may be simply slid out of casing 10 and a new casing 26 having a different type of tool supporting head attached thereto may be substituted. Further, should gears 28 or 30, crown gear 58, or pinion 35 wear, or otherwise become inoperative, and require adjustment or replacement, this can be most conveniently accomplisbed by sliding inner casing 26 out of outer casing 10, and substituting an entirely new assembly consisting of a new casing 26 and associated parts, while the old casing 26 with its associated parts may be returned to the factory for repair or adjustment as desired. Thus, the removability of casing 26, which carries all the operative parts ofthe dental handpiece with the exception of the turbine, allows the removal of these parts for adjustment or repair, or replacement, and at the same time allows a different type of tool supporting mechanism to be substituted for the one shown. This greatly increases the exibility of the tool herein described, as well as greatly simplifying the maintenance and replacement of the `operative parts.

Thus, it will be seen that this invention carries out its stated objects. The dental handpiece herein disclosed shows a self-contained handpiece which is adjustable within limits in order to provide the most convenient angle between the hand held instrument and the dental tool so that the dentist may conveniently work on any y 4 part of the patients teeth. It is simple and rugged in construction, and so designed that the change in angle between the bore and the handpiece does not effect the internal power transmitting parts.

While there has been shown and described the preferred forms of mechanisms of the invention, it will be apparent that various changes and modiiications may be made therein, particularly in the form Iand relation of parts, without departing from the spirit of the invention as set forth in the appended claims.

I claim:

l. A dental handpiece comprising, in combination, an elongated body portion, a turbine element mounted in said body portion for rotation about an axis substantially parallel to the longitudinal axis of said body portion, an eccentric element mounted on said turbine element, gear means rotatably mounted on said eccentric element, internally toothed gear means fixed to said body portion engaging said rotatably mounted gear means, a shaft having one end attached to said rotatably mounted gear means, second gear means mounted on the other end of said shaft, a driven shaft, gear means on said driven shaft meshing with said second gear means, and means on said driven shaft for gripping a dental tool.

2. A dental handpiece comprising, in combination, an elongated body portion, a turbine element mounted in said body portion for rotation about` an axis substantially parallel to the longitudinal axis of said body portion, an eccentric element mounted on said turbine element, a gear rotatably mounted on said eccentric element, an internal` gear means xed to said body portion and engaging said rotatably mounted gear means, a shaft having one end attached to said rotatably mounted gear means, second gear means mounted on the other end of said shaft, trunnion means engaging said body portion, a housing mounted on said trunnion means for limited rocking motion, a driven shaft in said housing, and crown gear means on said driven shaft for engaging said second gear means, with the pitch line of said crown gear means lying substantially on the axis of said trunnion means.

3.y A dental handpiece claimed in claim 2 and including means for locking said housing in adjusted position.

Case et al Mar. 8, 1898 Iseman July 29. 1941