US3578424A - Abrading machine for a preformed orthodontic band - Google Patents

Abstract

A MACHINE FOR FORMING A ORTHODONTIC INCISOR, CUSPID, BICUSPID OR MOLAR BAND IS PROVIDED. THE MACHINE IS PROVIDED WITH OPPOSED PERIPHERAL ABRADING WHEELS WHICH ARE PENDANTLY SUPPORTED WITH DRIVE MOTORS ON THE LOWER ENDS OF THE PENDANT ARMS AND A CONVEYOR MEANS MOVES THE BANDS INTO GRINDING POSITION.

Description

May 11, 1971 F, R, M|| ER ETAL 3,578,424

ABRADING MACHINE FOR A PREFORMED ORTHODONTIC BAND Filed Aug. 9, 1968 4 Sheets-Sheet l J0 waan May 11, 1971 F. R. MILLER ETAL 3,578,424

` ABRADING MACHINE FOR A PREFORMED ORTHODONTIC BAND Filed Aug. 9. 1968 4 Sheets-Sheet 2 ,....f Aw. 6. M ,Vf W \Ifu/na 4 new e F @M a@ MMM N. a .n w m ,ad WM v .Iv l u, r 4 dr a 1 MM Y wf M M ...xii 7 4.4 `Vf i May 11, 1971 F. R. MILLER ETAI- ED ORTHODONTIC BAND 4 4 sheets-sheet s Filed Aug. 9, 1968 fum May 11, 197l F. R. MILLER ETAL 3,578,424

ABRADING MACHINE FOR A PREFORMED ORTHODONTIC BAND Filed Aug. 9. 1958 4 Sheets-Sheet;

157'r 9 f7 .r/0

11 am y w y 220, i526. f@ Ms United States Patent Office 3,578,424 Patented May 1l, 1971 3,578,424 ABRADIN G MACHINE FOR A PREFORMED ORTHODONTIC BAND Frank R. Miller, Bradbury, and Raymond E. Dillberg,

Temple City, Calif., assignors to Ormco Corporation,

Glendora, Calif.

Filed Aug. 9, 1968, Ser. No. 751,555 Int. Cl. B24b 5 00 U.S. Cl. 51-89 5 Claims ABSTRACT OF THE DISCLOSURE A machine for forming an orthodontic incisor, cuspid, bicuspid or molar band is provided. The machine is provided with opposed peripheral abrading wheels which are pendantly supported with drive motors on the lower ends of the pendant arms and a conveyor means moves the bands into grinding position.

BACKGROUND OF THE INVENTION It is usual for the orthodontist to be supplied with a kit of tooth bands which are used in conjunction with other orthodontic devices and attachments. The tooth bands are fitted onto the teeth of the patient on a trial and error basis. The band must be ductile to permit it to be fitted exactly to the contours of the individual tooth. For sullicient strength and yet sutcient ductility the walls of the prior art bands have a thickness of the order, for example, of 3-6 mils.

The wall thickness of the prior art bands has created problems in the interproximal area since substantial tooth separation is required when the prior art bands are fitted into the mouth of the patient. This fitting can be painful, and the large wall thickness also results in a substantial space between the teeth to close after the bands have been removed. However, prior to the present invention, any attempt to provide a thinner band, especially for the molars, has resulted in a concomitant loss in strength of the band, which could not be tolerated.

In the practice of the present invention, however, the interproximal or mesial and distal sides of the band are thinned by a mild abrading or buing action. An appropriate metal such as stainless steel is used, so that the resulting thinning f the band at these areas is accompanied by a simultaneous hardening of the metal in the band so that no loss in strength is encountered. Although there is a loss in ductility in the buffed areas of the band, the remaining portions of the band which are unaffected by the bufling action provide the required ductility so as to permit the band to be fitted onto the tooth of the patient.

That is, the thinned walls of the band treated in accordance with the teaching of the present invention are strengthened by the abrading action. This means that there is no overall loss in strength of the band, and the remaining portion of the band remains sufficiently ductile to allow the necessary forming of the band over the tooth, as the band is fitted into the mouth of the patient. In the case of the molar bands, the upper or occlusal edge of the thinned parts is usually left in its original dimensions, so as to provide the orthodontist with a strong non-cutting edge to permit him to push the band down over the tooth without crumpling or bending of the edge.

Therefore, the hands formed by the machine of the present invention, having their interproximal portions thinned, are advantageous in that there is less total space between the teeth to close after the bands have been removed. Moreover, the application of the bands is less painful since there is less initial separation of the teeth required. This latter factor often results in less work for the orthodontist since, in many instances, the initial tooth separation step may be eliminated. Also, the use of the bands results in fewer problems of tooth relapse and rotation, as well as in greater patient comfort.

The improved buing or abrading machine to be described causes interproximal portions of the wall of the band to be thinned, by holding the band between a pair of buing or grinding wheels, or their equivalent, for a timed interval and determined pressure. The bufiing wheels are suspended as pendants and appropriate counterweights may be provided so that the Wheels bear against the sides of the band being treated with just the required amount of force so as to achieve the objective of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a typical preformed molar band which may be formed by the machine of the invention;

FIG. 2 is a top view of the preformed molar band of FIG. 1;

FIG. 3 is a side view, partly in section, showing the band of FIG. 1, as treated by the machine of the invention;

FIG. 4 is a front elevational view of an abrading machine for thinning the sides of the band of FIGS. 1 3, and which is constructed in accordance with the concepts of the invention;

FIG. 5 is a rear elevation of the machine of FIG. 4;

FIG. 6 is a fragmentary section showing a portion of one of the buffing wheels used in the machine of FIGS. 4 and 5, the other buing wheel having a similar construction;

FIG. 7 is a further front view of the machine of FIGS. 4 and 5, additionally showing a jig assembly in a withdrawn stand-by position;

FIG. 8 is a view like FIG. 7 of the machine and showing the jig assembly in an upright operative position, whereby tooth bands may be brought thereby between a pair of buing wheels in the practice of the invention;

FIG. 9 is a side view of the aforesaid jig assembly and showing its various internal components;

FIG. 10 is an end view of the jig assembly of FIG. 9 taken essentially along the line 10-10 of FIG. 9, and showing particularly a Geneva coupling which is used in the assembly;

FIG. 11 is a further end view of the jig assembly of FIG. 9 taken along the line 11-11 of FIG. 9, and showing particularly a cam operated control; and

FIG. 12 shows the details of a portion of the jig assembly which supports a tooth band, so as to convey the tooth band to the grinding wheels for buiiing purposes.

DETAILED DESCRIPTION OF THE INVENTION The tooth band shown in FIGS. l-3, as mentioned above, is a preformed molar band. The band is designated 10, for example, and, as shown, includes a distal side, a mesial side, a buccal side and a lingual side. When iitted in the mouth of the patient, for example, the buccal side is to the outside and the lingual side is to the inside. The tooth band also includes an upper edge, designated the occlusal edge, and a lower edge designated the gingival edge. In the practice of the present invention, and as best shown in FIG. 3, the mesial and distal sides are thinned by an abrading or buing action. In the case of the molar bands, the occlusal and gingival edges are preferably unthinned, so as to provide a surface for the orthodontist to force the 'band down over the tooth, with suicient edge strength to resist bending.

As mentioned above, an appropriate metal is used to form the bands, so that the bung and abrading action produces a simultaneous hardening of the metal in the band in the affected areas, so that there is no overall loss in strength. Moreover, the ductility of the remainder of the band is suflicient, so that the bands may be fitted onto the tooth, as easily as the prior art bands.l The resulting thinning in the interproximal contact areas provides the feature outlined specifically above.

The grinding machine of the invention is shown specifically in FIGS. 4-12. As shown in FIG. 4, for example, the machine includes a pair of buffing or abrading wheels 100 and 102, these wheels being rotatably mounted on the lower ends of a corresponding pair of arms 104 and 106. The arms, in turn, are pivotally mounted at their upper ends by shafts 108 and 110. The shafts are rotatably mounted in pillow block bearings 11211, 112b and 11411, 114b. The pillow blocks are mounted on a horizontal shelf 116 which is supported by supports 118. The supports 118, in turn, are mounted on an appropriate base 119. It will be appreciated, of course, that the wheels 100 and 102 may be replaced by other suitable abrading or buiiing means such as movable abrasive belts, or the like. Moreover, the abrading or buing means may be stationary and the bands rotated or otherwise moved relative thereto.

The buiiing wheels 100 and 102 in the illustrated ernbodiment are supported in a pendant manner on the arms 104 and 106, and are free to swing back and forth about the axes of rotation of the shafts 108 and 110. Drive motors 120 and 122 for the buing Wheels are also mounted on the lower ends of the pendant arms 104 and 106, behind the corresponding bufling wheels 100 and 102 in axial alignment, and with their drive shafts extending through the arms and mechanically coupled to the respective bufling or abrading wheels. The drive motors are connected to an appropriate electrical source through electrical leads 12011 and 12211 and through a switch 123.

The bufiing or abrading wheels 100 and 102 may each include a rim of hard rubber, plastic or felt as shown, for example, as 100a in FIG. 6. The rim may be impregnated with a grinding compound to enhance the actual abrading or buiiing action on the interproximal areas of each tooth band, as the band is held between the two bufting wheels. The force with which the buing wheels engage the band being buffed may be established, for example, by an appropriate setting of counterweights 122, 124 and 126, 128 on respective shafts 130, 132. The shafts 130 and 132 extend out from the upper ends of the respective arms 104 and 106.

A pair of uid cylinders 137 and 139 of any appropriate type responds to pressure in a line 136 (FIG. 5) to drive plungers against a pair of arms 10411 and 104k which extend down from the motors 120 and 122. This action serves to swing the two arms 104 and 106 in opposite directions and thereby separate the buiiing wheels 100 and 102. This action occurs, for example, between bufiing or abrading operations and when no buffing or abrading action is desired on the member placed between the buffing wheels 100 and 102, as will be described.

A jig holding assembly 200 for conveying the bands to be treated to the bufiing or abrading wheels 100 and 102 is best shown in FIGS. 7 and 8. `Of course, other suitable types of conveyors may be used. The jig assembly is hinged to the base 119 so that it may be tilted back (FIG. 7) to a standby position when not in use; or moved angularly to an upright position in which the tooth bands to be thinned by the bufling or abrading wheels 100 and 102 may be successively moved between the wheels by the jig assembly.

The jig assembly 200 rotatably supports a wheel 202, which is best seen in FIG. 11. The wheel 202 includes a series of radial members 204 which extend beyond the peripheral edge of the wheel 202, and whose extremities serve as support jigs for the bands to be thinned by the buiiing or abrading Wheels 100, 102. That is, each member 204 includes at its extremity a finger 20411 which extends radially beyond the periphery of the wheel. The

4 finger 20411 is positioned in facing relationship with another iinger 204b. The latter finger is integral with the wheel itself and is stationary. The fingers 20411, 204b serve as supports for the tooth band which is looped around the fingers.

Each member 20411 is pivotally mounted on a pin 205 in a bracket 203 on the side of the wheel 202 for movement normal to the plane of the wheel. The member 204 is biased out from the plane of the wheel by a spring 207, so that the fingers 20411, 204b are normally biased apart firmly to hold the band in its position around the fingers. The extent of displacement between the fingers is limited by a screw 209. Now, when the wheel 202 turns to move the band on the fingers 20411, 204b between the buffing wheels 100, 102, the interproximal sides of the band are buffed or abraded and thinned to the desired shape and dimension, as described in conjunction with FIGS. 1-3.

As the wheel 202 rotates, cam follower rollers 206 on the other end of the pivotally mounted members 204 engage a switch actuator 208 if there is no band about the fingers 20411, 204b. If there is a band around the fingers, it holds the rollers up out of engagement with the switch actuator and against the spring bias of the springs 207. When a roller 206 engages the switch actuator 208, a microswitch 230 is operated.

The operation of the microswitch 230 operates a solenoid valve 141 (FIG. 5) in the fluid line 136. This causes the iiuid cylinders 137, 139 to operate and spread the bufiing or abrading wheels 100, 102. This protects the lingers 20411 and 204b from being ground down by the bufiing or abrading wheels when no band is supported thereby.

The wheel 202 is mounted in a bracket 220 on a shaft 222. The shaft 222 is driven by an electric motor 224 which also is mounted on the bracket 220 (FIG. 9). The motor drive shaft 225 is coupled to the shaft 222 through a Geneva coupling or other such mechanism 226 (FIG. l0). This drive causes the Wheel 202 to rotate in an intermittent manner so that each tooth band supported on the fingers 20411, 204b at the end of its members 204 may be held in a bufiing or abrading position between the buffing or abrading wheels and 102 for a predetermined interval so that the desired bufiing or abrading action may proceed to predetermined dimensions.

The cam 208 is pivotally coupled to the microswitch 230 (FIG. 11). A wheel 232 is rotatably mounted on the cam 208 and is spring-biased by a spring 234 against a detent wheel 236. The detent wheel 236 is mounted on the shaft 222 to be driven by the motor 225 through the Geneva coupling or other mechanism 226. The detent wheel closes the microswitch while the tooth band held by the corresponding member 24 is moved between the bufiing or abrading wheels 100 and 102, so as to cause the bufling or abrading wheels to swing apart until the band is actually in position and ready for thinning.

As the wheel 202 turns, a cam 250 engages the cam followers 206 to pivot the members 204 about their pins 205 in FIG. 12 and close the fingers 20411 and 204b towards one another so that a band can be placed over the fingers at the loading station (for example, to the left in FIG. 11). Then, as the wheel 202 turns, the cam follower 206 moves oi the end of the cam 250 and the fingers 20411 and 204b are spring-biased apart by the spring 207 and against the inner edge of the tooth band placed thereon, firmly to hold the tooth band in place. As mentioned, if no tooth band has been placed over the fingers, the corresponding cam follower 206 next engages the switch actuator 208 in FIG. 11 to actuate the microswitch 230 and separate the bufiing or abrading wheels 100 and 102. This occurs as the corresponding member 204 approaches the bufling or abrading Wheels, and for the interval the corresponding member has its fingers 20411 and 204b in position between the wheels.

It will be appreciated, therefore, that the machine described above constitutes a convenient instrumentality for thinning the interproxirnal area of tooth bands, so that the tooth bands may exhibit the desired characteristics as described above. As pointed out previously, although a particular type of molar band is disclosed in FIGS. 1 3, the thinning principles of the present invention may be applied to any orthodontic tooth band in which the problems enunciated above are encountered.

Therefore, while the invention has been described in one of its aspects, other equivalent aspects may be practiced without departing from the spirit thereof. The following claims are intended to cover the various aspects of the invention.

What is claimed is:

1. A machine for bufiing or abrading selected portions of a thin-walled ductile orthodontic tooth band, said machine including:

-bracket support means;

first and second arms pivotally mounted at their upper ends to said bracket support means and extending vertically downwardly therefrom in side-by-side relationship;

grinding means comprising first and second bufling or abrading wheels rotatably mounted in side-by-side bufng or abrading relationship on the lower ends of said arms to be pendantly supported thereby from said bracket means to be free to swing back and forth about the respective pivotal axes of said arms and to engage such a tooth band with just the required amount of force to provide a bufiing or abrading action without crushing the band;

first and second drive motors for said bufling or abrading wheels respectively mounted on the lower ends of said arms and respectively mechanically coupled to said buing or abrading wheels; and

a conveyor assembly for moving successive thin-walled ductile orthodontic tooth bands to said grinding means to be buifed thereby without crushing.

2. The machine defined in claim 1 and which includes adjustable counterweights coupled to said arms to establish the force with which said first and second butfng or abrading wheels engage the aforesaid bands.

3. The machine defined in claim 1, in which said conveyor assembly includes a wheel having radially extending members providing support jigs for said bands, said support jigs being brought successively between said first and second buing or abrading wheels as said jig assembly rotates, an electric drive motor, and a coupling means intercoupling said drive motor and said conveyor assembly wheel to impart intermittent rotational movement to said conveyor assembly wheel.

4. The machine defined in claim 3 in which the extremities of said radially extending members extend beyond the periphery of said conveyor assembly wheel, and each includes a pair of fingers around which one of said bands may be positioned, and which separate from one another upon radial movement of the corresponding radially extending members to hold the band securely in place.

5. A machine for bufling or abrading selected portions of an orthodontic band, said machine including:

bracket support means; first and second arms pivotally mounted at their upper ends to said bracket support means and extending vertically downwardly therefrom in side-by-side relationship; first and second buting or abrading wheels rotatably mounted in side-by-side buing or abrading relationship on the lower ends of said arms t0 be pendantly supported thereby from said bracket support means; and a conveyor assembly for moving successive bands to said buing or abrading wheels to be butfed thereby, said conveyor assembly including a wheel having radially extending members providing support jigs for said bands, said support jigs being brought successively between said first and second buing or abrading wheels as said jig assembly rotates, the extrcmities of said radially extending members extending beyond the periphery of said conveyor assembly wheel, and each including a pair of fingers around which one of said bands may be positioned, and which separate from one another upon radial movement of the corresponding radially extending members to hold the band securely in place, and which includes cam followers on said members, and control means coupled to said arms to cause said buiiing or abrading wheels to swing away from one another, said control means having a switch actuator engaged by said cam followers in the absence of a band around the aforesaid fingers of said members to produce an actuation on said control means.

References Cited UNITED STATES PATENTS 2,691,254 10/1954 Robbins 5l-89 1,926,577 9/1933 Behle 5l-89 l,205,696 ll/l9l6 Beck 51-89 2,242,801 5/ 1941 Richardson 51-237X 3,430,388 3/1969 Gabrielli 51-l34 FOREIGN PATENTS 14,579 ll/1887 'Great Britain 51-89 322,913 10/1924 Great Britain 5l-89 HAROLD D. WHITEHEAD, Primary Examiner

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