Abstract:
A tool for rotating a component on a mechanism, to achieve linear and rotational movement of an element on the mechanism, involves three subassemblies mounted on the tool. Firstly, a reference unit that can engage with the mechanism to establish a stationary datum. Secondly, a drive assembly that can be rotated relative to the datum. Thirdly, an engagement member, selectively engaged between the component and the drive assembly for rotation of the component.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention pertains generally to adjusting tools. More particularly, the present invention pertains to tools that can be configured to cause a predetermined movement of a work object. The present invention is particularly, but not exclusively, useful as a tool for repositioning teeth in a dentition for subsequent use in the manufacture of a dental appliance. 
       BACKGROUND OF THE INVENTION 
       [0002]    In general, orthodontia is the branch of dentistry that is concerned with correcting and preventing irregularities of the teeth. In each case, the purpose is to have the upper and lower teeth meet with their respective cusps fitting close together. Stated differently, orthodontia involves the straightening of teeth in a dentition. As is well known, this process has heretofore most often required the use of wire braces. More recently, however, new systems for aligning teeth have been proposed. For example, U.S. patent application Ser. No. 11/230,323 for an invention entitled “Method and Apparatus for Repositioning Teeth”, which was filed by Kohani on Sep. 19, 2005, and assigned to the same assignee as the present invention (hereinafter the Kohani Application), discloses an orthodontic system in which a number of appliances are manufactured for sequential use. Importantly, successive appliances are manufactured with each one having a different predetermined configuration that will gradually reposition teeth of the dentition. 
         [0003]    To manufacture a series of orthodontic appliances, as suggested above, it is necessary to successively reposition several, or all, teeth in a dentition. In this endeavor, each tooth in the dentition needs to be considered for each appliance, and repositioned accordingly. In any event, the repositioning of each tooth must be done in accordance with a procedure that is prescribed by a trained orthodontist, and it must be done subject to his/her supervision. Despite the high level of knowledge and oversight that is required from the orthodontist, the actual manufacture of an orthodontic appliance is straight forward and, with proper instructions, can be accomplished by a trained laboratory technician. This, of course, requires the instructions be easily understood and the proper tool be provided for following the instructions. 
         [0004]    For the vast majority of orthodontic procedures, at least one tooth in the dentition needs to be moved fore or aft, left or right (i.e. in orthogonal directions) and/or rotationally about an axis defined by the tooth for each appliance in the series. Typically, the magnitude of tooth movements that are required between successive appliances will be small (e.g. &lt;1 mm or &lt;1°). Further, each tooth movement must have a known start point (i.e. the tooth location in the immediately preceding appliance). The Kohani Application recognizes these requirements and specifically provides for a model dentition in which individual teeth can be moved by external manipulation. 
         [0005]    In light of the above, it is an object of the present invention to provide a system for manufacturing a dental appliance wherein each prosthetic tooth in a model dentition can be individually repositioned without requiring the taking of a new impression each time the dentition is to be corrected. Another object of the present invention is to provide a tool for manufacturing a dental appliance wherein a simple rotation of the tool through an angle “θ” will result in a desired linear or rotational movement of a prosthetic tooth in a model dentition. Still another object of the present invention is to provide a system for manufacturing a dental appliance which is simple to use, relatively easy to manufacture and comparatively cost effective. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with the present invention, a tool is provided for rotating an adjustment component (e.g. a lead screw or a pinion) through a predetermined angle (θ). As intended for the present invention, this rotational movement results in the linear movement of a positioning element on an adjustment mechanism. The purpose here is to reposition a prosthetic tooth that is mounted on the element for subsequent use in the manufacture of a dental appliance. 
         [0007]    As envisioned for the present invention, the mechanism has two interactive elements that move in orthogonal directions. In this combination, each element is moved independently by its own adjustment component. For example, one component may be a rack and pinion type device, and the other may be a lead screw type device. Thus, in response to the rotation of a lead screw (or pinion), one orthogonal element of the mechanism will move the prosthetic tooth in an x-direction. A rotation of the pinion (or lead screw) of the other orthogonal element will then move it in a y-direction. These independent linear movements in the ‘x’ and ‘y’ directions are accomplished separately by directly engaging the tool with the respective adjustment component (pinion or lead screw). 
         [0008]    Mechanically, the rotation of the pinion (lead screw) through an angle “θ”, will result in a linear movement of the prosthetic tooth through a distance “d”. As mentioned above, depending on the element that is rotated, movement of the tooth may be in either the x-direction or the y-direction. In either case, the mathematical relationship is represented by the expression: “rθ=d”; wherein “r” is the radius of the rotated component (pinion or lead screw) measured in radians. As envisioned for the present invention, the desired tooth movement, “d”, is clinically predetermined. The angle of rotation “θ” required to achieve this movement can then be quantified by the mathematical expression. 
         [0009]    As envisioned for the present invention, the mechanism has an interactive element that provides for rotation of the tooth about the tooth&#39;s axis. Similar to the orthogonal elements, the rotation element is moved independently by its own adjustment component. For example, the rotational component may include a rotation arm (similar to a pinion) that is provided with a translating joint for connection to the rotation element. Thus, in response to the rotation of the rotation arm, the element of the mechanism will rotate the prosthetic tooth about its axis. This independent rotational movement about the tooth&#39;s axis is accomplished separately from the orthogonal movements by directly engaging the tool with the rotational adjustment component. Mechanically, the rotation of the arm through an angle “θ”, will result in a rotational movement of the prosthetic tooth through the same angle “θ”. 
         [0010]    For the present invention, the tool defines an axis, and it has essentially three interactive sub-assemblies. These are: a reference unit, a drive assembly and an engagement member. Functionally, the reference unit of the tool is engaged with the adjustment mechanism to thereby establish a stationary datum. The drive assembly, which is attached to the reference unit, can then be positioned relative to the reference unit as desired (e.g. positioned to establish the predetermined angle “θ”). Once the datum is established and the drive assembly has been properly positioned relative thereto, the engagement member is used to interconnect the drive assembly with the adjustment component that is to be rotated (pinion or lead screw). The drive assembly can then rotate the engagement member, together with the adjustment component (pinion or lead screw). This rotation continues, until the adjustment component has been rotated through the predetermined angle (θ). 
         [0011]    For rotational control, the tool includes a dial that is located at its proximal end. In detail, this dial identifies a fixed reference line and it has a moveable indicator. Specifically, when viewed together, the reference line and the indicator identify the angular relationship between the reference unit and the drive assembly. Importantly, the reference line and the indicator on the dial are, respectively, integral parts of the reference assembly and the drive assembly. 
         [0012]    Structurally, the drive assembly includes a base member. And, as implied above, the indicator on the dial is integrally connected to this base member. Further, the base member is formed with a tapered probe at its distal end, and it has a flange extending outwardly from the body of the base member. More specifically, the flange is distal the tapered probe. Structurally, the reference unit includes a key that extends from the tool in a distal direction. Importantly, the fixed reference line on the dial has an integrally fixed relationship with this key. On the other hand, as noted above, the indicator rotates on the dial together with the base member of the drive assembly. Consequently, when the indicator has been rotated through an angle “θ”, the flange will be positioned relative to the key, at the same angle “θ”. 
         [0013]    The engagement member of the tool is intended to simultaneously engage with the adjustment component (pinion or lead screw) on the adjustment mechanism, and with the drive assembly of the tool. Structurally, the engagement member is elongated and, preferably has a hex-head formed at its distal end. Its proximal end, on the other hand, is flared to establish a tapered cone. The engagement member also has a stem that extends axially in a proximal direction. As envisioned for the present invention, the stem is connected to the base member of the drive assembly in a manner that will allow the engagement member to freely rotate about the axis. It is also envisioned this connection will allow the engagement member to move axially through a limited distance, relative to the base member. Further, a spring is positioned on the stem to bias the engagement member and its hex-head in a distal direction from the base member. 
         [0014]    In the operation of the present invention, the key on the tool (i.e. reference assembly) is engaged with a keyway on the repositioning mechanism to establish the stationary datum. At the same time, the hex-head of the engagement member is engaged with the pinion (lead screw). During these engagements, the tool is in a first configuration wherein the engagement member and the drive assembly are disconnected. Next, while the tool is still in its first configuration, the indicator is positioned at the predetermined angle “θ” from the reference line. Note: this also positions the drive member at the angle “θ” from the reference line. The base member is then advanced farther in a distal direction, against the spring bias. This advancement establishes a friction engagement between the tapered probe on the base member and the tapered cone of the engagement member. It also places the tool in its second configuration. Once this friction engagement has been established (i.e. the second configuration for the tool), the drive assembly and hex-head can be rotated through the angle “θ”. Consequently, the adjustment component moves the prosthetic tooth through a distance “d” (recall: rθ=d), or rotates the prosthetic tooth about its axis by the angle “θ”. Note: rotation of the drive assembly can be done either manually, or electronically (if an internal battery is provided). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which: 
           [0016]      FIG. 1  is a perspective view of the system according to the present invention with portions shown in phantom for clarity; 
           [0017]      FIG. 2A  is a perspective view of the tool for the present invention positioned for engagement with a mechanism to move a work piece on the mechanism through a predetermined distance for purposes of the present invention; 
           [0018]      FIG. 2B  is a view of the tool shown in  FIG. 2A  when the tool is engaged with the mechanism for rotation of the tool through a predetermined angle; 
           [0019]      FIG. 2C  is a view of the tool shown in  FIG. 2B  after the tool has been rotated through the predetermined angle; and 
           [0020]      FIG. 3  is a schematic view of an adjustment component for use with the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Referring initially to  FIG. 1 , a system for repositioning a work piece in accordance with the present invention is shown, and is generally designated  10 . As shown, the system  10  includes a tool  12  and a mechanism  14 . More specifically, the tool  12  is selectively engageable with the mechanism  14  to manipulate the mechanism  14  for movement of the work piece (e.g. a prosthetic tooth  16 ). 
         [0022]    In detail, the tool  12  includes several essential subassemblies. These are: a reference unit  18 , a drive assembly  20 , an engagement member  22  and a dial  24 . As shown in  FIG. 1 , these various subassemblies are housed together in a casing  26  (shown in phantom). 
         [0023]    With specific attention to the reference unit  18  it will be seen in  FIG. 1  that this subassembly includes a key  28 . Importantly, the key  28  is affixed to a band  30  and, in turn, the band  30  is fixedly oriented relative to a reference line  32  on dial  24 . Further, it is seen that the key  28  extends from the tool  12  in a distal direction, and it is oriented substantially parallel to an axis  34  that is defined by the tool  12 . As intended for the present invention, the reference line  32  is an integral part of the reference unit  18  and is indicative of a stationary datum that is useable for monitoring and evaluating the operation of the tool  12 . 
         [0024]    In  FIG. 1 , the drive assembly  20  of tool  12  is shown to include an elongated base member  36  that defines the axis  34 . This base member  36  is formed with a tapered probe  38  at its distal end, and it is integrally attached to an indicator  40  that is moveable on the dial  24  relative to the reference line  32 . Accordingly, for purposes of the present invention, the drive assembly  20  (indicator  40 ) is able to rotate about the axis  34 , relative to the reference unit  18  (reference line  32 ). Thus, an observation of the relative positions of indicator  40  and reference line  32  on the dial  24  gives a visual indication of the angular relationship between the drive assembly  20  and the reference unit  18 . This angular relationship is indicated in the Figures by the angle “θ”. It will also be noted in  FIG. 1 , that the drive assembly  20  includes a flange  42 . Specifically, the flange  42  is mounted to extend outwardly in a radial direction from the base member  36 , and is located proximal the tapered probe  38 . Additionally, the drive assembly  20  is shown to include a connector  44  that joins the casing  26  with the base member  36 . Thus, the connector  44  can transfer a rotational force applied on the casing  26  to the base member  36  for rotation of the base member  36 . 
         [0025]    The engagement member  22  of tool  12  is shown, in  FIG. 1 , to be formed with a hex-head  46  at its distal end. As will be appreciated by the skilled artisan, however, the hex-head  46  is only exemplary, as various other engagement configurations could be used. In any event, the proximal end of the engagement member  22  is shown formed as a hollow tapered cone  48 . Specifically, the tapered cone  48  is dimensioned to receive the tapered probe  38  of the drive assembly  20  in a mating engagement. Specifically, the intention of the present invention is that the tapered probe  38  of the drive assembly  20  can be joined with the tapered cone  48  of the engagement member  22  for joint rotation, together. For this purpose, a friction engagement is envisioned, and textured mating surfaces on the cone  48  and probe  38  may enhance such an engagement. Other structural components that will accomplish this same purpose are envisioned for the present invention. 
         [0026]    Still referring to  FIG. 1 , the engagement member  22  is shown to have a stem  50  that extends along the axis  34  in a distal direction from the engagement member  22 . For purposes of the present invention, this stem  50  orients the engagement member  22  with the drive assembly  20 . When the engagement member  22  is not engaged with the drive assembly  20 , however, the stem  50  also allows the engagement member  22  to rotate independently about the axis  34 . Further,  FIG. 1  also shows that a spring  52  is positioned on the stem  50  to bias the engagement member  22  in a distal direction from the drive assembly  20 . 
         [0027]    As shown in  FIG. 1 , the mechanism  14  includes an element  54  that engages with an adjustment component  56  for movement of the element  54  back and forth in an x-direction, as indicated by the arrows  58 . Similarly, the mechanism  14  includes an element  60  that engages with an adjustment component  62  for movement of the element  60  back and forth in a y-direction, as indicated by the arrows  64 . Also, the mechanism  14  includes an element  65  that engages with an adjustment component  67  for rotational movement of the element  65  about the z-axis (i.e., the axis of the tooth  16 ), as indicated by the arrows  69 . While  FIG. 1  illustrates that the element  65  rotates about the z-axis, the element  65  may be designed for rotation about the x-axis or y-axis, if desired. Further, the mechanism  14  is formed with a keyway  66   a  adjacent the adjustment component  56 , a keyway  66   b  adjacent the adjustment component  62 , and a keyway  66   c  adjacent the adjustment component  67 . As envisioned for the system  10  of the present invention, the elements  54 ,  60  and  65  interconnect with each other in such a manner that causes the elements  54 ,  60 , and  65  to move together in the y-direction, while the element  54  can be moved independently of the elements  60 ,  65  in the x-direction, and the element  65  can be rotated independently of the elements  54 ,  60 . For this particular arrangement, the combination of element  54  and component  56  would preferably be a rack-and-pinion assembly of a type well known in the pertinent art (i.e. the rack is element  54 , and the pinion is component  56 ). On the other hand, the combination of element  60  and component  62  would preferably be a lead screw assembly, also of a type well known in the pertinent art. Further, the combination of element  65  and component  67  would preferably be a rotation-translating joint, also of a type well known in the pertinent art. 
         [0028]    For the operation of the system  10 , reference is collectively made to  FIGS. 2A ,  2 B and  2 C. For purposes of clarity in the illustration, element  65  and component  67  are not shown in the figures subsequent to  FIG. 1 . To begin, FIG.  2 A shows an initial contact between the tool  12  and the mechanism  14 . Specifically, this contact occurs when the hex-head  46  of the engagement member  22  is positioned in contact with the adjustment component  56 . Also, at this point, the key  28  of reference unit  18  can be aligned with the keyway  66   a  on the mechanism  14 . Further, the indicator  40  can be rotated to position the drive assembly  20  at a proper angle “θ”. 
         [0029]    After contact has been established between the tool  12  and the adjustment component  56 , the casing  26  is advanced in a distal direction toward the mechanism  14 . This places the tool  12  in a first configuration (see  FIG. 2B ), and engages the tool  12  with the mechanism  14  for rotation of the adjustment component  56 . More specifically, as shown in  FIG. 2B , when the tool  12  is in its first configuration, the tapered probe  38  of the drive assembly  20  is engaged with the tapered cone  48  of the engagement member  22 . Also, the key  28  of reference unit  18  is engaged with the keyway  66   a . Importantly, with the engagement of key  28  with keyway  66   a , a reference datum  68  is established for the tool  12 . The tool  12  can then be rotated toward the reference datum  68 , and through the angle “θ”, to change the tool  12  from its first configuration (see  FIG. 2B ) into a second configuration (see  FIG. 2C ). 
         [0030]    In  FIG. 2C , it will be seen that several aspects of the tool  12  have changed. For one, the flange  42  has been rotated through the angle “θ”. Specifically, with this rotation, the flange  42  is brought into contact with the key  28  (i.e. reference datum  68 ). Indeed, this contact ensures the tool  12  has rotated through the angle “θ”, and only through the angle “θ”. At the same time, the dial  24  gives a visual indication that the drive assembly  20  has rotated through the angle “θ”. The import of all this is, of course, that the adjustment component  56  has also been rotated by the engagement member  22  through the angle “θ”. The consequence of this will be best appreciated with reference to  FIG. 3 . 
         [0031]    In  FIG. 3 , the element  54  and the adjustment component  56  are taken as being exemplary of a mechanical movement for the prosthetic tooth  16 , as envisioned by the present invention. In this example, the element  54  is considered as being a rack, and the component  56  is considered as being a pinion, in a rack-and-pinion assembly. Then, if the pinion  56  has a radius “r” (as shown), and the angle “θ” is expressed in radians, the distance “d” that the element  54  will be moved by a rotation of the component  56  can be calculated from the expression d=rθ. A similar statement can be made for the consequence of rotating the component  62  through an angle “θ”. The overall result is that by using the tool  12  to selectively rotate the components  56 ,  62 , and  67 , the elements  54 ,  60 , and  65  can be moved, linearly, in the directions of arrows  58  and  64 . Further, rotation of the component  67  through an angle “θ” results in rotation of the element  65  through a substantially equal angle. The overall result is that by using the tool  12  to selectively rotate the components  56 ,  62 , the elements  54 ,  60  can be moved, linearly, in the directions of arrows  58  and  64 . Further, the tool  12  can be used to selectively rotate the component  67  to rotate the element  65  in the direction of arrows  69 . This respectively achieves predetermined movements of the elements  54 ,  60  through linear distances d x  and d y  and predetermined rotation of the element  65  through angle θ T , wherein angle θ is substantially equal to angle θ T  (see  FIG. 1 ). 
         [0032]    While the particular Tool for Use With a Tooth Repositioning Mechanism as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.