Abstract:
A mechanism for animated characters capable of visually communicating facial expressions is provided. The mechanism ( 10 ) has two mesh gears per upper or lower lip (FIG.  1   b ). One gear of each pair is rotated by a single drive ( 20, 22 ). Each gear has two guidance devices ( 60, 62, 56, 58 ). Rotation of any gear to which the elastomeric material ( 80 ) is connected via a guidance device results in the stretch or ability to retract the elastomeric material. Secondary guidance devices ( 64, 66, 68, 70 ) on a gear, when in contact with the elastomeric material, cause an inflection or deflection of the elastomeric material. Resulting stretch or bending of the elastomeric material mimics facial expressions.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the priority of U.S. Provisional Application Ser. No. 60/381,722 entitled “Expressive Feature Mechanism for Animated Characters and Devices” filed on May 17, 2002, and PCT/US03/15120 filed on May 14, 2003, the entire contents and substance of which are hereby incorporated in total by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a mechanical apparatus used to cause various expressions on the face of an animated character. 
   2. Description of Related Art 
   This invention pertains to an expressive feature mechanism used in an animated character. The goal of this invention is to achieve a full range of human-like and recognizable facial expressions. This goal has been addressed by others and has often led to the development of devices used in animated characters that have mouths, which open and close to mimic speaking or sucking. Examples of such work would be U.S. Pat. No. 4,808,142 by Berliner, which has a motor driven mouth actuator to move the mouth between open and closed positions. 
   U.S. Pat. No. 2,250,916 by Magruder uses electromagnetic coils to animate the upper and lower lip in synchrony to sound. 
   U.S. Pat. No. 3,841,020 by Ryan employs a complex set of levers and actuators that allow a range of facial expressions connected to the motion of a dolls arms. 
   U.S. Pat. No. 3,828,469 by Giroud describes a mechanism having two operating rods for moving upper and lower lips. 
   More recently issued patents describe techniques that allow for a greater control of lip motion. For example, U.S. Pat. No. 6,352,464 by Madland et al. describes a mechanism for an animated character. The Madland Patent describes a facial control system comprising of two lip chains embedded behind two lips. The lip chains are attached at either end as well as at a center portion. By positioning the movable center portion relative to the moveable ends various facial expressions can be achieved, however, the described mechanism does not allow for stretching of the lips as it occurs on human and animal faces. 
   Other methods such as the one described in U.S. Pat. No. 4,177,589 by Villa demonstrate a pneumatic mechanism to open and close the mouth. This method allows for a rounding of the lips but does not allow for a full range of expression such as a frown or broad smile. 
   Mechanisms such as U.S. Pat. No. 6,544,098 by Hampton are capable of some recognizable expressions but only with the addition of other actions such as drooping ears or closing eyes. 
   The current invention comprises a means to make animated characters with complex facial expressions in a minimal component, minimal cost mechanism. With the described invention it is possible to make a full range of motions with a minimum of moving components. 
   SUMMARY OF INVENTION 
   Briefly described, the invention comprises of a pair of wheels or meshed gears used to generate human-like expressions. On each wheel or gear there is an attachment point and a device for inflecting or deflecting an elastomeric or flexible material or device. The primary goal of the wheels or gears is to stretch or allow for contraction of the elastomeric or flexible material or device attached to a point along a radius. Meshing of the gears allows for a reduction of drive sources while maintaining bilateral symmetry of motion. Independent wheels allow for asymmetric motion. In a meshed gear mechanism, one gear and its attachment point mirror the other in the pair. If one gear in the pair turns clockwise, the other gear in the pair turns counterclockwise. Since attachment points mirror each other on each gear of a pair, rotation of the pair would either increase or decrease the distance between each attachment point. An elastomeric or flexible material or device encircling the attachment points stretches or contracts as the gears turn. The inflection-deflection devices offer an increase in the recognition of an exaggerated expression produced by the bending of the elastomeric or flexible material or device. 
   A more rudimentary expressive system can be produced without the bending of the elastomeric or flexible material or device between its attachment points. The elastomeric or flexible material or device can comprise a variety of conformations, ranging from a continuous band to a molded mask hiding and yet attached to the entire mechanism. The transmission of movement from the gears to the elastomeric or flexible material or device may also occur via indirect coupling such as magnetism. 
   The invention advantageously provides a moving lip mechanism for animated characters or devices that is simple in its design and construction. The device is capable of producing a range of motions in a range of speeds able to simulate a variety of expressions and mouth movements. With the synchronization of sound the device can simulate smooth, realistic vocalization. 
   This invention will be described further with reference to the following drawings. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1   a  is an isometric view showing a pair of dual gear single drive mechanisms using motors with non-integrated encoding with the elastomeric material in place around attachment points on each of the gears. 
       FIG. 1   b  is a support frame removed isometric view showing a pair of dual gear single drive mechanisms using motors with non-integrated encoding with the elastomeric material in place around attachment points on each of the gears. 
       FIG. 1   c – 1   e  are additional views showing a pair of dual gear, single drive mechanisms using motors with non-integrated encoding with the elastomeric material in place around attachment points on each of the gears. 
       FIG. 2  is an isometric view of an expression driving gear shown with an unused portion of its teeth removed. 
       FIG. 3   a – 3   l  are various top views showing the gear arrangement and relative position of the attachment points and inflection-deflection points to present the elastomeric material in an expression. 
       FIG. 4   a – 4   c  are isometric, top and side views respectively of a pair of dual gear, single drive mechanisms with the elastomeric material in place around attachment points on each of the gears. 
       FIG. 5   a – 5   c  are isometric, top and side views respectively of a single drive four gear, rack and pinion mechanisms with the elastomeric material in place around attachment points on each of the gears. 
       FIG. 6   a  is a isometric view showing a pair of dual gear, single drive mechanisms with an angular offset and the elastomeric material in place around attachment points on each of the gears. 
       FIG. 6   b  is an isometric view showing a pair of dual gear single drive mechanisms with an angular offset. 
       FIG. 6   c  is a front view showing a single dual gear, single drive mechanism with an angular offset. 
       FIG. 6   d – 6   e  are top and side views respectively showing a pair of dual gear, single drive mechanisms with an angular offset. 
       FIG. 7   a – 7   d  are isometric, front, side and top views respectively of a single drive, two gear, mechanism with the elastomeric material in place around attachment points on each of the gears and fixed points on the mechanisms frame. 
       FIG. 8  is an isometric view showing a pair of dual gear, single drive mechanisms with the elastomeric material being represented as a flexible mask in place around attachment points on each of the gears. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   During the course of this description, like numbers will be used to identify like elements according to the different views that illustrate the invention. 
   Referring to  FIGS. 1   a – 1   e , the mechanism  10 , according to the preferred embodiment, comprises a lower motor support frame  19 , an upper motor support frame  18  and a gear support frame  17 . The motor support frames secure two motors  20  and  22 , which in turn have small motor drive gears  24  and  26  respectively attached to their perspective drive shafts. Gears  24  and  26  mesh with reduction gears  28  and  30  respectively. The reduced diameters of reduction gears  28  and  30  mesh with primary expression driving gears  32  and  34  respectively. Positional sensing of the primary expression driving gear  32  is achieved by variable resistance or positional contacts on control board  40 . It is understood that other commercial means of encoding of position would be equally effective in positional sensing. Magnetic encoding, transmission slots counting, and reflective encoding are examples of other common methods of rotational encoding. Primary expression driving gears  32  and  34  in turn mesh with secondary expression driving gears  44  and  46  respectively. Each expression driving gear has one attachment point and one inflection-deflection pin affixed to a point in relation to the radius of each respective expression driving gear. Each gears attachment point and inflection-deflection pin are at a fixed degree apart from one another. In the case of primary expression driving gear  32 , it has attachment point  60  and inflection-deflection pin  66  affixed. In the case of primary expression driving gear  44 , it has attachment point  62  and inflection-deflection pin  64  affixed. In the case of primary expression driving gear  34 , it has attachment point  56  and inflection-deflection pin  68  affixed. In the case of primary expression driving gear  46 , it has attachment point  58  and inflection-deflection pin  70  affixed. Fitted around the four attachment points is elastomeric material  80 . To prevent the return rotation of the primary and secondary expression driving gears, gearlocks  82  and  84  fits into the teeth of secondary expression driving gears  44  and  46  respectively. Gearlock  82  is allowed to release secondary expression driving gear  44  by being pulled by solenoid  90  and pivoted on axis  86 . Gearlock  84  is allowed to release secondary expression driving gear  44  by being pulled by solenoid  92  and pivoted on axis  88 . 
     FIG. 1   a  of the preferred embodiment illustrates an isometric view of the preferred embodiment of the mechanism  10 . In this view, the attachment points  56 ,  58 ,  60 , and  62  for holding the elastomeric material  80  represent lips, in a smiling expression. As used in this disclosure the term “attachment point” could be a post, a pin or any other projecting means capable of contact with, support of, or attachment to elastomeric material  80 . In the preferred embodiment, power to the motors  20  and  22  (see also  FIG. 1   b ) is not applied once the desired position is sensed by control board  40 . Instead, position is maintained against the pull of elastomeric material  80  by securing against rotation with the gearlocks  82  and  84  (see also  FIG. 1   b ). Rotation of the motors and change in expression of  10  as represented by the position of  80  is allowed by the activation of solenoids  90  and  92 , see also  FIG. 1   b , and the pull back of respective gearlocks  82  and  84 . 
     FIG. 1   b  of the preferred embodiment shows the same isometric view as  FIG. 1   a  but with the removal of support frames  17 , 18 , 19  and circuit board  40  for clarity, see also  FIG. 1   a.    
     FIG. 1   c  and  FIG. 1   d  also describe the preferred embodiment and show a right side and front view of the mechanism  10 . These views give clear perspectives of the relative positions of reduction gears  28  and  30  to their meshed small motor drive gears  24  and  26  and primary expression driving gears  32  and  34 . 
     FIG. 1   e  also describing the preferred embodiment illustrates a top view of the mechanism  10 . This view would be the side that faces forward and represents the mouth of an animated character or design. 
     FIG. 2  describes an alternate embodiment of either the primary or secondary expression driving gear assemblies. In this figure, the gear  94  has been reduced in dimension to minimize overall construction size. Since only about 180 degrees of rotation is needed to reproduce most recognizable facial expressions, the non-meshed portions of the gear have been cut off. The support arm  94  would preferably be manufactured into a position that fits its need as a primary expression diving gear or secondary expression driving gear. 
     FIGS. 3   a – 3   l  illustrates examples of expression driving gear arrangements and their effect on the elastomeric material stretched around the attachment points.  FIG. 3   a ,  FIG. 3   b  and  FIG. 3   c  show arrangements approximating a smile.  FIG. 3   d  to  FIG. 3   g  show expressions ranging from surprise to talking intermediates.  FIG. 3   h – FIG. 3   k  shows arrangements emulating sadness and anger.  FIG. 3   l  shows the mechanism at rest. 
     FIGS. 4   a – 4   c  shows an alternate embodiment  11  of the preferred mechanism represented as  10  in  FIGS. 1   a – 1   e . In this embodiment, servo motors  100  and  102  replace the small motors as a means to drive the primary expression driving gears  104  and  106  respectively. This arrangement eliminates the need for a gearlock mechanism since position is maintained for as long as power is applied or until the servo receives instructions to reposition itself. The primary expression driving gears  104  and  106  mesh with secondary expression driving gears respectively. In this embodiment  11 , the attachment points  112 ,  114 ,  116 , and  118  are affixed directly to the expression driving gears  104 ,  106 ,  108  and  110 . 
   Referring to isometric  FIG. 4   a  and top view  FIG. 4   b  which illustrate a pair of dual gear single drive mechanisms, an elastomeric material  128  is placed in position in contact with attachment points  112 ,  114 ,  116 , and  118 . Gears  104  and  106  are attached to servo drives  100  and  102  respectively with integrated gear reduction and positional sensors. As motor drives  100  and  102  rotate, driving their attached gears  104  and  106  respectively, their meshed gears  108  and  112  in turn rotate in the opposite directions. The rotation of the meshed gears results in the radial displacement of the attachment points  112 ,  114 ,  116 , and  118 . As the gears  104 ,  106 ,  108 , and  110  rotate, the elastomeric material in contact with the attachment points  112 ,  114 ,  116 , and  118  gets pulled, or is allowed to contract, as the attachment points travel in a path defined by their placement on the gear&#39;s radius. In the event that the rotation of the gears  104 ,  106 ,  108 , and  110  causes the inflection-deflection points  120 ,  122 ,  124 , and  126  to travel beyond a point defined by a line drawn between the two attachment points  112 ,  114 ,  116 , and  118 , the elastomeric material will be stretched to accommodate the radial movement of the inflection-deflection points  120 ,  122 ,  124 , and  126 . 
     FIG. 4   c  is a schematic side view of a pair of dual gear single drive mechanisms. Clarity is further enhanced in  FIGS. 4   a  and  4   b  by showing the relative positions of the drives  100  and  102 , the gears  104 ,  106 ,  108 , and  110 , the attachment points  116  and  118 , the inflection-deflection points  122  and  126 , and the elastomeric material  128 . 
   Referring now to isometric  FIG. 5   a  and top view  FIG. 5   b  of a single drive four gear rack and pinion mechanisms  12 , an elastomeric material  150  is placed in position in contact with attachment points  160 ,  162 ,  164  and  166 . Pinion expression driving gears  152  and  155  are meshed with racks  144  and  146  that can be moved by the action of levers  136  and  138  respectively. Levers  136  and  138  are rotated on their fulcrums  140  and  142  respectively by the force applied by pin  134  as the result of the rotation of wheel  132 . As wheel  132  attached motor drive  130  rotates, the displacement of levers  136  and  138  causes the movement of a racks  144  and  146  to rotate its respectively matched pinion expression driving gear  152  and  154 . The secondary expression driving gears  156  and  158  rotate in the opposite direction of their meshed primary expression driving gears  152  and  154  respectively. The rotation of the meshed expression driving gears  152 ,  154 ,  156  and  158  result in the radial displacement of the attachment points  112 ,  114 ,  116 , and  118 . As the gears rotate, the elastomeric material  150  in contact with the attachment points  112 ,  114 ,  116 , and  118  gets pulled, or is allowed to contract, as the attachment points travel in a path defined by their placement on the gears radius. 
     FIG. 5   c  is a schematic side view of a single drive four gear rack and pinion mechanism  12 . Clarity is further enhanced from  FIG. 5   a  and  FIG. 5   b  by showing the relative positions of the drive  130 , the wheel  132 , levers  136  and  138 , racks  144  and  146 , the pinion expression driving gear  154 , the attachment points  112 ,  114 ,  116 , and  118 , the inflection-deflection points  120 ,  122 ,  124 , and  126 , and the elastomeric material  176 . 
     FIGS. 6   a ,  6   b ,  6   c  and  6   d  illustrate an alternate embodiment  13  of the preferred mechanism represented as  10  in  FIGS. 1   a – 1   e . In this alternative embodiment  13 , servo motors  180  and  182  replace the small motors as a means to drive the primary expression driving gears  184  and  186  respectively. This technique eliminates the need for a gearlock mechanism since position is maintained for as long as power is applied or until the servo receives instructions to reposition itself. The primary expression driving gears  184  and  186  mesh with secondary expression driving gears  188  and  190  respectively. In this alternative embodiment  13 , the expression driving gears  184 ,  186 ,  188  and  190  have their gear teeth set at an angle to allow the gears to rotate on separate planes. By setting the gears at an angle it is possible to better fit the model of a human or animal face, if desired. Attachment points  200 ,  202 ,  204  and  206  are affixed to support arms  194 ,  198 ,  196  and  192  respectively. Inflection-deflection points  212 ,  214 ,  208  and  210  are affixed to support arms  194 , 198 ,  196  and  192  respectively. The support arms  192  and  194  are affixed to primary expression driving gears  184  and  186  respectively. The support arms  196  and  198  are affixed to secondary expression driving gears  188  and  190  respectively. An elastomeric material  216  is placed in position in contact with attachment points  200 ,  202 ,  204  and  206 . 
   Referring to isometric  FIG. 6   a  illustrating a pair of dual gear single drive mechanisms, an elastomeric material  216  is placed in position in contact with attachment points  200 ,  202 ,  204  and  206 . Primary expression driving gears  184  and  186  are attached to servo drives  180  and  182  respectively with integrated gear reduction and positional sensors. As motor drives  180  and  182  rotate, driving their attached primary expression driving gears  184  and  186  respectively, their meshed secondary expression driving gears  188  and  190  in turn rotate in the opposite direction. The rotation of the expression driving gears  184 ,  186 ,  188  and  190  results in the radial displacement of the attachment points  200 ,  202 ,  204  and  206 . An elastomeric material  216  is placed in position in contact with attachment points  200 ,  202 ,  204  and  206 . As the expression driving gears  184 ,  186 ,  188  and  190  rotate, the elastomeric material  216  in contact with the attachment points  200 ,  202 ,  204  and  206  gets pulled, or is allowed, to contract as the attachment points  200 ,  202 ,  204  and  206  travel in a path defined by their placement on the expression driving gear&#39;s radius. In the event that the rotation of the attachment points  200 ,  202 ,  204  and  206  causes the inflection-deflection points  212 ,  214 ,  208  and  210  to travel beyond a point defined by a line drawn between two attachment points  200 ,  202 ,  204  and  206 , the elastomeric material will be stretched to accommodate the radial movement of the inflection-deflection points  212 ,  214 ,  208  and  210 . 
     FIG. 6   b  is an isometric view of alternative embodiment  13 . Primary expression driving gear  186  and meshed secondary expression driving gear  190  are shown rotated so that support arms  194  and  198  present attachment points  200  and  202  in a position that would reflect a smile similar to the one demonstrated in  FIG. 3   a . The inflection-deflection points  212  and  214  then contact the elastomeric material to further stretch the material in the form of a smile. 
     FIG. 6   c  is a side view of one servo drive  182  and one meshed pair of expression driving gears  186  and  190 . Removal of one drive and a meshed gear pair adds clarity to the view of how angular displacement of the expression driving gears  186  and  190  is achieved. The relative position of support arms  194  and  198  as well as attachment points  200  and  202  and inflection-deflection points  212  and  214  is visible. 
     FIG. 6   d  and  FIG. 6   e  are top and side views, respectively, of alternative embodiment  13 . Primary expression driving gear  186  and meshed secondary expression driving gear  190  are shown rotated so that support arms  194  and  198  present attachment points  200  and  202  in a position that would reflect a smile similar to the one demonstrated in  FIG. 3   a . The inflection-deflection points  212  and  214  then contact the elastomeric material to further stretch the material in the form of a smile. 
   Referring to  FIGS. 7   a – 7   d , the mechanism  14  further comprises of a lower motor support frame  234 , an upper motor support frame  232 , and a gear support frame  230 . The motor support frames secures one motor  236 , which in turn has a small motor drive gear  238  attached to the drive shaft. Gear  238  meshes with reduction gear  240 . The reduced diameter of reduction gear  240  meshes with primary expression driving gear  244 . Positional sensing of the primary expression driving gear  244  is achieved by variable resistance or positional contacts on control board  246 . It is understood that other commercial means of encoding of position would be equally effective in positional sensing. Magnetic encoding, transmission slots counting, and reflective encoding are examples of other common methods of rotational encoding. Primary expression driving gear  244  in turn meshes with secondary expression driving gear  242 . Each expression driving gear has one attachment pin and one inflection-deflection pin affixed to a point in relation to the radius of each support arm&#39;s respective expression driving gears at a fixed degree apart from one another. In the case of primary expression driving gears  242 , it has attachment point  252  and inflection-deflection pin  262  affixed. In the case of primary expression driving gear  244 , it has attachment point  254  and inflection-deflection pin  260  affixed. Attachment points  256  and  258  are fixed to an immobile point in such a way as to allow for attachment of elastomeric material  264 . Fitted around the four attachment points is elastomeric material  264 . To prevent the return rotation of the primary and secondary expression driving gears, gearlock  248  fits into the teeth of secondary expression driving gear  244 . Gearlock  248  is allowed to release secondary expression driving gear  244  by being pulled by solenoid  250  and pivoting around an axis. 
     FIG. 7   a  is an isometric view of the of the mechanism  14 . In this view, the attachment points  252 , 254 , 256 , and  258  are shown holding the elastomeric material  264 , representing lips, in a smiling expression. In this embodiment, power to the motor  236  is not applied once the position is sensed by control board  246 . Instead, position is maintained against the pull of elastomeric material  264  by securing against rotation with the gear lock  248 . Rotation of the motor and thus change in expression of  14  as represented by the position of  264  is effected by the activation of solenoid  250  and the pull back of gearlock  248 . 
     FIG. 7   b  of this embodiment illustrates a top view of the mechanism  14 . This view would be the side that faces forward and represents the mouth of an animated character or design. 
     FIG. 7   c  and  FIG. 7   d  of this embodiment show a side and top view of the mechanism  14 . These views give clear perspectives of the relative position of reduction gear  240  to its meshed small motor drive gear  238  and primary expression driving gear  244 . 
     FIG. 8  is a completed unit  15  illustrating placement of an elastomeric mask  220  around a pair of dual gear single drive mechanisms  11  as represented in  FIG. 4   a . In this figure the inflection-deflection points engage ridges or grooves embedded in the material of the mask&#39;s construction. Accordingly, the invention can include an elastomeric material which is either a circle with a hole therein, or wherein the attachment points and inflection-deflection pins touch the elastomeric material or engage ridges therein, or which the hole may be alternatively comprised of continuous elastomeric membrane material surrounded by elastic lip sections. 
   While the invention has been described with reference to the preferred embodiment thereof it will be appreciated by those of ordinary skill in the art that modifications can e made to the parts that comprise the invention without departing from the spirit and scope thereof.