US 2201190 A
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Description (OCR text may contain errors)
May 21, 1940- c. D. MAsTRUD 2,201,190
DENTAL DEVICE Filed Jan. 5, 1939 Patented May 21, 1940 UNITED STATES PATENT OFFICE Conrad D. Mastrud, Chicago, Ill.
Application January 3, 1939, Serial No. 248,986
This invention relates to improvements in dental devices.
One object of the invention is,l to provide power means for operating a toothbrush or like appli- 5 Gator or massaging device in relatively small paths in the plane of the portion of the gums or teeth being treated whereby the eifect of the treatment can be concentrated uniformly upon a denite part or parts of the gums or teeth without excessive rubbing or abrading action which may tend to injure affected tissues. In the treatment of many dental cases, l1v have found that delicate massage of the gums is of denite benefit, but that it is best applied by an applicator such as a brush moving in a very restricted path over the gums so as not to abradethe high points or ridges of the tissue surface and inadequately treat the low points or valleys between the ridges. The amplitude of movement of the brush should be such that when the flexible bristles'are placed against the gums the individual bristles will be restricted to substantially rotary paths close to the longitudinal axis of the respective bristles and hence will not be drawn from the low points over the high points. By thus localizing the action of the bristles, the gum surface including the tissue in the embrasure spaces between the teeth can be massaged uniformly by the sides of the bris`l tles without injuring the tissue of the high portions by substantial relative movement of the free ends of the bristles. 'Ihe capability of the improved deviceto massage or clean in Well defined localized areas by holding the operating member for a brush or the like relatively stationary, enables the user easily to avoid treating a sore or tender spot in the gums while obtaining the benefit of the massaging action on closely adjacent tissues.
Another object of the invention is to provide a brush operating member to and from which brushes or similar massaging oreleaning means can be readily attached or detached, the shanks or handles of which brushes extend axially from the operating member and are operated thereby and cooperate with the operating member to prevent the entrance of water, cleansing paste, or other foreign substance into the adjacent end of the operating member and the mechanism carried thereby.
A further object of the invention is to provide an operating member provided with mechanism adapted to be actuated by an electric motor, for example, which mechanism transmits power from the motor to a brush or the like carried by the operating member, and translates the rotary action of the motor into circular or elliptical motion in the brush whereby the free ends of the bristles move in rather minute paths in the plane of the bristle ends. i
Another object of the invention is to provide a 5 brush operating member comprising a hand manipulatable casing which is light in weight and the mechanism in which is adapted to be actuated by an electric motor via a flexible shaft, in which member is provided means to prevent ro- `10 tation of the casing of the operating member by the exible shaft when the member is laid down with the motor running.
A further object of the invention is to provide a brush operating member comprising a casing and' l5 a brush actuating arm extending exteriorly of the casing and means cooperating with said member for guiding the same and preventing entrance of foreign matter into the casing or passage of lubricant therefrom. y
Other objects relate to various features of constructionand arrangement of parts which will be apparent from a consideration of the following specification and accompanying drawing where- Fig. 1 is a side elevation of a dental device embodying the present improvements;
Fig. 2 is a sectional view taken on line 2-2 of Fig. 1;
Fig. 3 is a sectional view taken on line 3-4-3 of 30 Fig. 2;
Fig. 4 is a sectional view taken on line 4-4 of Fig. 2; j
, Fig. 5 is a section taken on line 5-5 of Fig. 2;
Fig. 6 is a section taken on line 6-6 of Fig. 2.
In Fig. 1 of the drawing, a handvmanipulatable casing l0 is shown provided with mechanism4 therein for operating a massaging or cleaningde vice,rsuch as a toothbrush, indicated by numeral 40 I I. The mechanism within the casing I0 preferably is operable by means of a flexible shaft l2 comprising an outer nonrotatable sheath l2a and a driven shaft 12b Within the latter which in turn is connected to an electric motor, not shown in 45 detail, but housed within a casing I3, the casing preferably being provided with a base I3a which supports the motor when the same is placed upon a table or other horizontal support, and which may be provided with an eye I3b by means of 50 which the motor may be supported in thevertical position shown in Fig. 1 when desired. The casing Hl in the form illustrated comprises two mat- .ing sections |0a and Illb` secured together by means of screws I4 or the like. Horizontally ds- 55 posed within the casing is a shaft I 5 which is supported by a suitable bearing or journal I6. The rear end of the shaft I5a is tubular and of somewhat greater diameter than the remainder of the shaft. The tubular portion I5a is slotted as at |51) for the reception of a driving end I7 which is secured to the forward end of the flexible shaft I2b. The member I7 is provided with a pin I8 disposed diametrically thereof, the ends of which are receivable in the slots |577 to provide a driving coupling connection between the drive shaft I2b and the shaft I5. The rear portion of the interior of the casing member Ilia, as shown in Fig. 2, is provided with recesses or cavities I9 and 20 beneath which is a bridging member 2I which forms one support for the bearing or journal IB.
Disposed approximately centrally of the casing IB is a bevel gear 22 having teeth which mesh with the teeth of a pinion 23 mounted on the forward end of the shaft I5. The gear 22 is provided with a lower axial extension 22a which is journaled in a bearing member 24, and at the opposite side is provided with a co-axial shaft extension 25 which is journaled in a bearing member 26 carried by the casing section Ilia. Beneath the journal or axial extension 25 is an eccentric or cam member 27 which may be made as a portion of thegear or as a portion of the shaft comprising sections 22a and 25. The eccentricity of the member 27 with respect to the axis of the shaft is quite small. For dental purposes, where brushes areemployed for providing the desired massaging and cleaning action, I have found that an eccentric off-set from the axis of the shaft a distance of less than 1/20 ofv an inch is satisfactory, so that the maximum throwy of the eccentric or cam is less than le of an inch. The degree of eccentricity may be varied, but for massaging purposes I have found the above best suited for the purposes mentioned.
This eccentric member 27 determinesone diameter of the circular or elliptical path through which th'e bristles move during operation of" the device, and-hence, as stated above, an eccentric of small throw is desirable( In the embodiment of the structure disclosed, a sleeve 28 is carried by the eccentric 27 into which extend diametrically opposite studs 23a. Upon the studs are pivotally mounted the extremities of arms of the yoke 29 which constitute the rear end of an operating arm indicated generally by the numeral 33.' The arm`3IB` is disposed Within a longitudinal passage 3l formed in the forward portion of the casing, and has its extreme forward end disposed outwardly of the casing. This forward end, indicated by numeral 36a, preferably is provided with opposite convergent .nat sides 35h, while the upper and lower surfaces Sc are rounded and also convergent. A catch is carried by the end 36a, which may be in the form of a pair of balls SIIC, portions of which are spring-pressed beyond the at surfaces 3073y for inter-engagement within a socket of a removable toothbrush or like applicator, as will be describedhereinafter.
The varm 3D is provided with a pivotal guide member within ,the passage 3| at a point adjacent the forward end of the casing I. This `guide member preferably is in the form of a ball 32 which seats in a spherical recess 33, one-half of which is formed in each of the casing sections Ilia and Ilib. The ball is provided with a rearwardly projecting sleeve 34 through which said arm extends. Surrounding the arm 3B, adjacent the forward end of the sphericalpivoting member 32, sealing means are provided for preventd ing the entrance of foreign matter along the arm into the recess in the member 32, through which the arm projects. This member, which is indicated by the numeral 35, may be in the form of a molded washer of exible material such as sponge or other rubber, which is retained in position by means of an annular ring 36 which frictionally seats over the forward reduced end of the casing I0.
In operation, the flexible shaft I2b effects rotation of theshaft I5, the pinion 23 on the end of which causes rotation of the gear Z2 and, likewise, of the eccentric or cam member 27. The rotation of the eccentric about the axis of the pinion produces rotary movement of the rear end of the arm with the result that the arm not only moves to and fro or longitudinally within the recess 3|, but it has a pivotal movement imparted thereto by the bearing 32, the bearing pivoting about an axis parallel with the axis of the gear 22 is viewed in Fig. 2. The flexible sealing member 35 compresses and expands in response to the described movement of the arm for maintaining a constant seal around the arm 34, and is retained against inward displacement by spherical bearing 32 and against outward displacement by the flanged ring 3E during the operation of the arm.
A brush, such as indicated by numeral II, flares outwardly toward its rear end and preferably terminates in an annular flange 37 which prevents water or paste from iiowing beyond the end of the brush shank and finding its way into the interior of the shank and possibly from the f latter along the arm into the mechanism Within the casing. While the flexible sealing member 35 is designed to prevent the entrance of such matter, the flange 30 is an additional safeguard against the admission of cleansing powder or paste or such other matters as may cause the lubricant Within the casing from becoming fouled and hard, and thereby impairing the operation of the mechanism.
The shank IIa of the toothbrush is provided with a socket IIb, the walls of which are shaped in conformity with the walls 3th and 30o of the tang or forward end 30a of the arm 30. Small depressions 33 preferably are formed in opposite walls of the socket recess for receiving the prol,
jecting portions of the balls or catch members 30C for releasably retaining the brush in position on the arm. As shown in Fig. 2, `the rear extremity of the shank IIa is recessed as at 39 to accommodate the forward end of the casing I0 and in fact extends rearwardly of the said forward end for the purpose of guarding against the passage of foreign matter into contact with the forward end of the arm 30 from which it may possibly work past the sealing member 35 and into the ball 32. The recess 39 is of adequate length and diameter to accommodate the movement of the shank imparted thereto by the arm 3B during operation of the device.
The bristles 40 of the brush extend in a direction parallel with the axis of the gear 22 whereby that is, the diameterY extendingl transversely with reference-,to the longitudinal axis of the casing Ill is determined by the throw `of the eccentric in connection with the relative lengths of arm 30 between the pivot and brush and the pivot and yoke respectively. In the modification shown, the distance from the pivotal axis of the ball 32 to the bristles of the brush is somewhat greater than the distance from the axis of the ball 32 to the axis of the gear 22. Hence, with such an arrangement, the paths of movement of the bristles will be slightly elliptical, the major diameters extending transversely of the brush. Hence when the brush is held against the teeth with `the handle horizontal, in the manner of an ordinary toothbrush, and the device is set in operation, the bristles will move a slightly greater extent up or down, or longitudinally of the teeth, than in a direction transversely of the teeth whereby the embrasure spaces between the teeth may more effectively be cleaned. It will be seen that due to the relatively small major and minor diameters of the paths of movement of the base ends of the bristles, that upon application of the brush to the surface of the teeth and gums that the free ends of the bristles will remain stationary while the bodies of the bristles are swung around in a relatively small elliptical path with the brush back, whereby a localized area of the teeth or gums may be massaged or treated by the sides rather than the free ends of the bristles while the manipulatable handle IU is held stationary. It is thus possible by the use of this device to localize the treatment in relatively confined areas of the gums and avoid application to infected or tender spots or portions where such is desirable. At the same time, the relatively small diameters of the paths of movement of the individual bristle ends enables the flexible bristles to be pressed against a definite area of the gums including high and low spots, and treat all portions of such area substantially uniformly without causing the bristles to sweep across the high spots and impose excessive treatment on the latter, and insufficient massaging action on the low spots, as would be the case were the brush operated in a sweeping or reciprocating movement of greater amplitude.
As indicated, this massaging device may be hung up at a convenient position where it will be accessible to all members of the family, for example, each member having his own individual brush which can readily be attached to the tang or forward end 30d of the arm 30. The device likewise is useful in dental offices where brushes individual to particular patients may be provided and where brushes or applicators of different types may be employed for treating special cases.
As shown in Figs. 2 and 3, the sheath I2a of the flexible shaft I2 is provided with a terminal portion 4l provided with an annular flange 42 which seats in an annular recess 43 formed in the casing, one-half of such recess being formed. in each of the sections Illa and |012. The member 4| preferably is provided with a pin 44 which projects into an adjacent similar recess 45. A pin 46 or other stop member is provided in the recess 45 which limits the rotation of the casing I0 with reference to the member 4l to an angle slightly less than 360. Thus should the casing I0 be laid upon a table or other like support while the motor is running, the casing and brush will not be rotated about its longitudinal axis beyond the angle where the members 44 and 46 come into engagementisee Fig. 5). `The mechanism within the casing may be lubricated satisfactorily by placing oil or grease within the longitudinal passage through which the shaft l5 and. arm 3|] extend. A flexible retainer member 4l surrounding the arm 30 preferably is employed adjacent the rear end of the guide sleeve 34 to prevent migration of grease'used for the gear 22 and pinion 23 along the arm 30. Oil or lighter grease may be provided in the chamber 48 which constitutes an enlargement of the axial passage 3l and within which the sleeve 34 oscillates. Oil circulation openings 49 may be provided in the sleeve and ball member, as shown in Figs. 2 and 3. Escape of the lubricant outwardly of the casing is ini hibited by the flexible member 35.
While I have shown and described an embodiment of the invention for the purpose of illustra-tion, I do not Wish to be restricted specifically thereto as various changes may be made in the details of construction without departing from the spirit of the invention.
What I claim as new and desire to cover by Letters Patent is:
l. A power operated toothbrush comprising a handle constituting a casing, a brush carrying member extending into said casing, means within said casing for imparting movements to said member in both transverse and longitudinal directions, a pivotal mounting for said member within said casing arranged and adapted to support said member for sliding and rocking movements whereby the outer end of said member is caused to move in a substantially rotary path, said movement imparting means being so arranged and said mounting being so disposed with respect to the inner and outer ends of said member as to cause the base of each bristle of a brush carried thereby to move in a substantially circular path the maximum diameter of which is being restricted within the range where the frictional engagement of the free end of the bristle and teeth or gums will prevent substantial relative movement thereof, whereby cleaning and' massaging action is produced by the sides rather than the free ends of the bristles.
2. A power operated toothbrush comprising a handle constituting a casing, brush operating mechanism supported within said casing and including an eccentric having its axis of rotation extending transversely of said handle and a rigid brush operating arm having a sleeve operatively engaging said eccentric at one end and its forward end disposed outwardly of said casing, a'
pvoted bearing for said arm within said handle, the throw of said eccentric being of such proportions and said bearing being so disposed with respect to the ends of said arm as to cause the 4base of the bristles'of a brush carried thereby to move in a substantially circular path the maximum diameter of said path being restricted within the range where the frictional engagement of the free ends of the bristles with the teeth or gums will prevent substantial relative movement therebetween, whereby cleaning and massaging action is produced by the sides rather than the free ends of the bristles.
3. A power operated toothbrush comprising a hand manipulatable casing having an axial passage therethrough, a rotary driven shaft 'in said passage adjacent the rear end thereof, a motor, a flexible drive shaft operable thereby and having an end disposed in said passage, means coupling said drive shaft to said driven shaft, a pinion on said driven shaft, a gear meshing with said pinion for operation thereby and having the axis `thereof disposed transversely of said passage, a
cylindrical cam eccentrically mounted on said gear, an operable sleeve on said cam, a brush operating arm disposed in the forward portion of said passage and having the forward end thereof disposed outwardly of said casing, the rear end of said arm being operatively engaged by said sleeve whereby rotary movement is imparted to said end of the arm and to and fro movement of the arm as a whole is effected during operation of said gear, and a movable spherical bearing member in a forward portion of said passage through which said arm extends and oscillatable on an axis parallel with the axis of said gear for imparting rotary movement to the outer end of said arm and an applicator carried thereby, the throw of said eccentric being of such proportions and said bearing member being so disposed with respect to the ends of said arm as to cause the base of the bristles of a brush carried thereby to move in an elliptical path the maximum diameter of said path being restricted Within the range Where the frictional engagement of the free end of the bristles with the teeth and gums will prevent substantial relative movement thereof, whereby cleaning and massaging action is produced by the sides rather than the free ends of thebristles of a brush.
CONRAD D. MASTRUD.