Interchangeable Tool Operating Apparatus With Plural Motion

Motor-driven dental treatment devices have been used professionally, by dentists and dental hygienists, for a long time, and more recently they have been available for home use, and in portable forms using batteries that may be rechargeable. Examples are shown in U.S. Pat. Nos. 3,029,451; 3,145,404; 3,195,537; 3,220,039; 3,258,802; 3,275,919; 3,739,416; 3,757,419; 3,802,420; 3,921,298; 3,939,599; and 4,004,344. The prior devices provide a single form of motion; generally a rotatable brush or gum treatment tool is available; in some, tools for various purposes are available interchangeably. For example, U.S. Pat. No. 3,029,451 shows a dental tool 39 which can be formed for cleaning teeth or for gum massage, but in either case it rotates on a shaft 38; and U.S. Pat. No. 3,802,420 has as its object to provide a portable rotary hygiene device which is capable of removably mounting additional rotary work heads. In U.S. Pat. No. 3,848,336 a portable professional dental instrument shows provisions for interchanging prophylaxis tools and drills.

Dental stimulators are devices intended to be inserted between proximal surfaces of two adjacent teeth. The tapered rubber or plastic tip at the end of a toothbrush handle is a familiar example, which is shown in U.S. Pat. No. 2,141,969. Some have proposed to discharge cleaning fluids through an inter-proximal stimulator or massage implement; examples are shown in U.S. Pat. Nos. 2,187,560; 3,199,510; and 3,391,696. These are non-rotating devices for hand use only. Blasi U.S. Pat. No. 3,195,537 (mentioned above) shows a scheme for dispensing a dentifrice through a power driven rotary tooth cleaner and gum stimulator.

The present invention provides a novel tool operating apparatus, exemplified in a dental treatment device capable of driving alternatively at least a first tool and a second tool, each tool being intended to execute a different form of motion. The device comprises essentially a single tool driving means to which each of several different tools can be removably coupled. The driving means includes a drive shaft journaled in a support for rotation around its longitudinal axis. A portion of the shaft extending from the support is fitted with tool engagement means. One tool can be fitted over the shaft to engage the tool engagement means so as to rotate the tool with the shaft. A second tool can be fitted over the shaft, with means on the tool to engage the support so that the shaft can rotate within the tool, but the tool will not rotate with the shaft. The second tool has means for cooperating with the shaft so as to execute an oscillatory motion relative to the shaft axis. Tools capable of two optional forms of oscillatory motion are disclosed--in one the motion is parallel to the axis of the shaft; in another the motion is nutational. A tool engagement means in the form of a disc affixed to the shaft and lying in a plane that makes an acute angle with the rotational axis of the shaft is useful for engaging and/or driving a variety of tools. The drive shaft can be provided with a fluid passage along its rotational axis through which to provide a fluid such as a dental treatment agent, an endodontal treatment material, or other fluid to the tools, and each form of tool can be fitted with ducts for dispensing such an agent or material.

The support mounting the drive shaft can be affixed in a separable fashion in known ways, to any available drive mechanism, such as an electric motor, and thereby is useable interchangeably with other motor-driven tool operating apparatus, dental instruments, and the like.

FIG. 1 is a partially-exploded view of a dental treatment device employing two different tools;

FIG. 2 is a partial section of FIG. 1 showing the common tool-driving means;

FIG. 2A shows an alternative structure for a component of FIG. 2;

FIG. 3 is a similar section showing a rotational tool attached to the tool driving means;

FIG. 4 is an end view of the rotational tool on line 4--4 in FIG. 3;

FIG. 5 is a similar section showing an oscillatory tool attached to the tool driving means, the tool being in a retracted position;

FIG. 6 is a view like FIG. 5 showing the oscillatory tool in an extended position;

FIG. 7 is a section like FIG. 4, 5 or 6 showing a non-rotating tool that is adapted to execute a nutational motion;

FIG. 8 illustrates a variation of the non-rotational tool of FIGS. 5 and 6 as adapted for endodontal use;

FIG. 8A shows a tool that can be substituted in FIG. 8; and

FIG. 9 is an outline of one form of hand-held motor drive to which the invention can be attached.

FIG. 1 is a partially exploded schematic view of a dental treatment device 10, having a transmission shaft 12 fitted with a driving gear 14 in a housing 16, all adapted to be fitted to a driving motor (not shown) as will be explained. The transmission shaft drives a tool drive shaft 20 via bevel gears 22,24 on the end of the transmission shaft and a geared disc 28 fitted to the tool drive shaft, respectively. The geared disc has gear teeth 24 on one side (upper side in the figure) and is smooth on the opposite side 29. A tool-engagement disc 26 is fixed to the tool drive shaft in a region between the lower extremity 28 and a housing part 30 which supports the geared disc 28 at its flat side. A rectangular flanged boss 32 is fitted to the outer side of the housing part 30, for holding one of the tools 34 non-rotatably attached to the device. The tool engagement disc 26 lies in a plane making an angle other than a right angle with the rotational axis of the tool drive shaft 20. Another of the tools 36 is adapted to engage the tool engagement disc via an aperture 38, so as to rotate with the tool drive shaft 20. The non-rotatable tool 34 has an aperture 50 into which the tool drive shaft 20 and tool engagement disc 26 can fit, for driving the non-rotatable tool in an oscillatory path, as will be explained with the aid of FIGS. 5 and 6.

FIG. 2 shows the tool holding part of the device 10, enlarged to show details of the tool drive shaft 20 and its supporting and driving mechanisms. The geared disc 28 and the tool drive shaft 20 are shown as one piece, with an axial bore 40 through it. The forward end 42 of the housing 16 has a passage 44 mating with the upper end (in the figure) of the bore 40, for passing a dentifrice or other oral treatment agent into and through the bore. Such an agent can be introduced at a receiving aperture 46, which may be fitted with a directional valve (not shown) as will be described. The housing parts 42 and 30 may be made of a rigid plastics material, and may be fixed together with a cement, as is known. They may alternatively be made of metal. The lower part 30 has an upper flat surface 31 on which the lower smooth surface 29 of the geared disc 28 can be supported for rotation; if desired a low friction washer (not shown) of a material such as Teflon can be located between the confronting surfaces 29 and 31. The tool drive shaft 20 and its geared disc 28, and the transmission shaft 12 are preferably made of metals suitable for small mechanical parts which should have high mechanical strength. While the tool drive shaft 20 and the geared disc 28 are shown as one part, the shaft 20 can be made separable from the disc 28, as by threading the shaft into the disc (FIG. 2A), if it is desired to provide interchangeably a plurality of different tool drive shafts. The tool engagement disc 26 is shown with a cylindrical peripheral surface 27 which enhances the utility of the device for some purposes, as will be explained with reference to FIGS. 5 and 6. The lower extremity 28 of the tool drive shaft may extend beyond the tool engagement disc a distance that is suitable for the variety of functions it is desired to achieve, as will also be explained. The upper extremity of the tool drive shaft 20 engages in a socket 43 in the upper housing part 42.

Referring now to FIGS. 3 and 4, the rotatable tool 36 has a socket 39 within its aperture 38 for engaging the tool engagement disc 26; this socket embraces the periphery of the disc 26, so that the tool 36 rotates with the tool drive shaft 20. The rotatable tool has a bore 41 which registers with the bore 40 in the tool drive shaft, for conducting a treatment agent (when present) into a cup 37 at the lower extremity of the tool. At its upper end the rotatable tool abuts the lower surface 54 of the lower housing part 30.

The cup 37 has a design suitable for polishing teeth, or performing other oral or dental treatment, and may take any well-known form. As will be understood, the rotatable tool 36 can be made of soft rubber or a plastics material having similar resilient properties, so that it can be attached to the tool drive shaft 26, and removed from it, manually.

FIGS. 5 and 6 show the non-rotatable tool 34 fitted to the tool drive shaft 20. This tool is intended to execute an oscillatory motion parallel to the rotational axis of the tool drive shaft when the latter is rotating. In executing this oscillatory motion the tool 34 is alternately retracted toward the lower housing part 30 to which it is attached, as is shown in FIG. 5, and extended from the housing part 30 as is shown in FIG. 6. The extended position is shown by a dashed line outline 54 in FIG. 5.

The non-rotatable tool 34 is fitted to the lower housing part 30 by engaging the flanged boss 32 with an inwardly facing rim 51 that fits in a groove 31 in the boss. Like the rotatable tool 36, the non-rotatable tool may be made of resilient rubber or a plastics material that is resilient, so that it can be manually fitted to the flanged boss 32, and removed from it. The boss is made rectangular in plan, so that the tool 34 cannot rotate around the rotational axis of the tool drive shaft 20. Obviously, other means to prevent rotation of the non-rotatable tool 34 can be employed; the illustrated shape is easy and convenient to make.

Between the rim 51 and the main body of the non-rotatable tool 34 is a compliance part 52 which is elastically stretchable in the direction of the rotational axis of the tool drive shaft 20, and tends to restrain the tool in the retracted position shown in FIG. 5. Within this part 52 the tool 34 has return-limit rim 53 which comes to rest on the lower confronting surface 54 of the lower housing part 30 when the non-rotatable tool is in the fully retracted position shown in FIG. 5. At the lower end this tool tapers to a tip 55, for interproximal dental use, and a duct 57 which registers with the bore 40 in the tool drive shaft 20 conducts an oral or dental treatment agent (when present) to ducts 58,58 exiting near the tip 55. The bore 50 which receives the tool engagement disc 26 and shaft 20 has a diameter similar to that of the cylindrical peripheral surface 27 of the tool engagement disc, so that the latter disc can rotate within the bore 50 while making only slight contact with the walls of the bore. The bottom wall 56 of the bore 50 is slanted relative to the rotational axis of the tool drive shaft 20, at an angle which may be the same as the angle between the tool engagement disc 26 and that axis; however, these two angles need not necessarily be the same. Owing to the elasticity of the compliance part 52, the bottom wall 56 is at all times in contact with the limited portion 60 of the tool engagement disc which extends the greatest distance from the housing 42, 30. As the tool drive shaft rotates, that portion 60, which may be considered the contact point for driving the non-rotatable tool, moves in a circular path on the bottom wall 56, around the axis of rotation of the tool drive shaft. When the contact point 60 is at the part of the bottom wall 56 which is furthest removed from the rim 51, the tool is in its fully-retracted position, as is shown in FIG. 5. When the contact point 60 is at the part of the bottom wall which is nearest to the rim 51, the tool is in its fully-extended position, as is shown in FIG. 6. As the tool drive shaft 20 is rotated, the non-rotatable tool cyclically extends and retracts, thereby executing an oscillatory motion parallel to the axis of the tool drive shaft. This motion is suitable for dental treatment use as an interproximal stimulator.

It will be observed in FIG. 6 that when the tool 34 is in its fully-extended position the tool engagement disc 26, the bottom wall 56 and the wall of the aperture 50 define a chamber 62 which has its maximum volume. It will likewise be observed in FIG. 5 that when the tool 34 is in its fully-retracted position this chamber 62 has its minimum volume. During oscillation of the non-rotating tool 34, the volume of chamber 62 changes cyclically between the maximum and minimum limits, and the chamber is therefore useful as a pump. Recalling that the access opening 46 to the passage 44 may be fitted with a valve which allows fluid passage only into the bore 40 in the tool-drive shaft 20, the pump can be employed during expanding volume of the chamber 62 to bring a dental or oral treatment agent into the chamber via that bore. For that purpose, the exit ends of ducts 58 may be formed as slit-valves 59 (shown closed in FIG. 6), to reduce the opportunity of air to enter the chamber 62 during expansion of its volume. During contracting of the volume of the chamber 62, the access passage 46 will be closed and the treatment agent will be expelled through the ducts 58,58. To facilitate the pump action described, the lower end of the shaft 20 near the extremity 28 should fit loosely in the recess 56' that is shown in the bottom wall 56.

A one-way valve 64 is shown in the access opening 46 in FIG. 5, as an example of a suitable valve that is inexpensive to make. A tube 66, through which a supply of dentifrice or other dental or oral treatment agent may be furnished, has an end 68 which is closed but for a slit 64, fitted into the access opening 46, which functions as a socket for the end 68. When pressure in the tube 66 exceeds pressure in the connecting passage 44, the treatment agent will force the slit 64 open and the treatment agent will flow into the bore 40. This pressure condition can be brought about by applying increased pressure in the tube 66, as by an external pump (not shown), or by reducing pressure in the bore 40, as by expanding the volume of the chamber 62, in the manner described above; or both forces may be employed simultaneously.

FIG. 7 shows another embodiment of a non-rotatable tool 70, which resembles the non-rotatable tool 34 except that the bottom wall 72 of its bore 74 is not slanted relative to the rotational axis of the tool-drive shaft 20. That is, the contact point 60 of the tool engagement disc runs in a circular path on the bottom wall which, in the absence of stretching by the disc 26, is everywhere the same distance from the rim 51. When the tool 70 is installed on the groove 31 in the boss 32, the tool engagement disc stretches the compliance part 76 in a limited region corresponding to the location of the contact point 60 on the bottom wall 72, displacing the tip 78 away from the rotational axis of the tool drive shaft 20. The bottom wall 72 has a recess 82 in it to receive loosely the extremity 28 of the tool drive shaft 20, and the mating duct 80 in the tool 70 is opened sufficiently to receive a treatment agent from the bore 40, so that as the shaft 20 rotates the tip 78 will execute a nutational motion while receiving the treatment agent and dispensing it through ducts 84. The dotted line 79 illustrates a position in the nutational cycle of the tip 78. The cylindrical surface 27 of the tool engagement disc 26 can be maintained in contact with the wall of the bore 74 sufficiently to confine the treatment agent to the chamber 86 between the disc 26 and the bottom wall 72. In this case, it will be observed that the volume of that chamber 86 remains more nearly constant than does the volume of the chamber 62 in FIGS. 5 and 6.

FIG. 8 and 8A show an embodiment of the invention employing a variation of the second tool 34 in FIGS. 5 and 6 that is suitable for use in endodontal work. The remote portion of the tool, beyond the compliance part 52, including the pump chamber 62, is fitted at the end 92 with a socket 94 through which a duct 96 communicates with the pump chamber. A one-way valve 98 is fitted in the duct, for passing fluid out of the pump chamber 62 when the volume of the chamber is contracting; this valve closes when the volume of the chamber is expanding. A tube 102 is removably fitted in the socket for carrying fluid expressed from the pump chamber to a root canal in a tooth under treatment (not shown). A material intended to be introduced into the root canal is supplied, for example, through the bore 40 from a source (not shown) via the one-way valve 64 at access opening 46, as shown in FIG. 5.

A reamer 104, useful for preparing a tooth for root canal treatment, can be substituted for the tube 102. In that event, the duct 96 will be plugged and the pump action of chamber 62 will not be used, but the reamer will execute the oscillatory motion parallel to the rotational axis of the drive shaft 20 that is described above with reference to FIGS. 5 and 6. For endodontal purposes, the amplitude of this motion may desirably be in the range 2 to 3 millimeters. This can be achieved by choosing appropriate angles between the tool engagement disc 26 and the shaft 20, and between the bottom wall 56 and the shaft axis. As is mentioned above, the shaft 20 can be made separable from the geared disc 28 (FIG. 2A), enabling the user to select an appropriate angle for the tool engagement disc, depending on the use to which the apparatus is to be put.

FIG. 9 is a general illustration of a tool drive apparatus of the invention, as illustrated in FIG. 1 with the rotating tool 36 in place, attached to a housing 108 enclosing batteries 116 and an electric motor 114 having a shaft 112 fitted at its remote end with a driving gear 110 to which the gear 14 of transmission shaft 12 is meshed. Mounting means for detachably holding dental and other tools to a housing encasing a motor with or without batteries (the latter being, if desired, fitted with means to charge or recharge the batteries) are by now well-known, and are not illustrated. A flexible bottle 118 for supplying, for example, a dentifrice to the rotatable tool 36 via a tube 120 to the access opening 46 is also known per se in the prior art. A clamp 120 is suggested to hold such a device in place.

The illustration in FIG. 9 is by way of example only, and is in no sense intended to suggest any limitation on the uses to which the invention may be put. For example, tools having abrasive or felt-like surfaces, and treatment agents having abrasive or polishing properties, can be used in the laboratory, to aid in preparing crowns, bridges and dentures, or in the manufacture of jewelry. It is contemplated that all parts of the invention as illustrated in the drawings, except the transmission shaft 12 and the geared disc 28 and the tool-drive shaft 20 with tool engagement disc 26 may be made of plastics or rubber materials when the invention is intended for domestic use, as a dental care device, as to brush the teeth and to provide superior inderdental stimulation. On the other hand, it is contemplated that a more rugged professional version of the invention, or one requiring greater attention to miniaturization, will be made entirely, or more nearly entirely, of various metals, some of which may be selected for high tensile strength and/or corrosion resistance. Application of the invention to endodontal practice, for example, would require attention to miniaturization, as well as to ruggedization and sterilization. It is therefore to be understood that the description of embodiments herein is by way of example only, and not intended to limit the claims that follow.