Abstract:
A joint for use in toys, such as dolls, includes a first member including at least a portion of a ball and a second member including a socket which receives the at least a portion of the ball. A protrusion is formed on the first member adjacent to the ball such that when the ball is received in the socket a rotation about a longitudinal axis of the first member is permitted while at least partially restricting bending in a plane of the longitudinal axis.

Description:
FIELD OF THE INVENTION 
   The present invention generally relates to infrastructure for dolls and more particularly to joint structures for dolls and toys. 
   BACKGROUND OF THE INVENTION 
   Many doll skeleton include pivot joints for arms legs, shoulder and hips for dolls. In some instances these joints are simple hinges. Hinges provide limited motion and do not permit rotation relative to the longitudinal axis of a member to which the joint is attached. In some cases these joints have an additional rotational joint, which contributes to the degrees of freedom of the connection but creates an arbitrary and unnatural motion. 
   In other structures, linkages are employed which include a series of ball and socket joints. These provide sufficient flexibility to arms and legs of the doll, but don not limit the movement of these appendages when they are extended beyond natural ranges of motion. This is particularly true for structures including these ball and socket joints for the spine or backbone of the doll. Ball and socket joints employed in the backbone can often lead to unnatural contorsions not normally possible in humans. 
   Therefore, a need exists for a skeletal structure for dolls and toys, which limits motion of at least the backbone to provide a more natural motion for the doll or toy. 
   SUMMARY OF THE INVENTION 
   A joint for use in toys, such as dolls, includes a first member including at least a portion of a ball and a second member including a socket which receives the at least a portion of the ball. A protrusion is formed on the first member adjacent to the ball such that when the ball is received in the socket a rotation about a longitudinal axis of the first member is permitted while at least partially restricting bending in a plane of the longitudinal axis. 
   The first member may include longitudinal grooves, and the second member may include longitudinal grooves. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The advantages, nature, and various additional features of the invention will appear more fully upon consideration of the illustrative embodiments now to be described in detail in connection with accompanying drawings wherein: 
       FIG. 1  is an exemplary backbone portion of a toy skeleton in accordance with one embodiment of the present invention; 
       FIG. 1A  is a cross-sectional view taken at section line  1 A— 1 A of  FIG. 1 ; 
       FIG. 2  is a partial cross-sectional view of a spine joint in accordance with one embodiment of the present invention; 
       FIG. 3  is a partial cross-sectional view of a skeleton joint providing rotational motion in accordance with another embodiment of the present invention; 
       FIG. 4  is a partial cross-sectional view of a skeleton joint having rotational limits in accordance with another embodiment of the present invention; 
       FIG. 4A  is a front view of a skeleton joint similar to that in  FIG. 4  having rotational limits in accordance with another embodiment of the present invention; 
       FIG. 5  is a partial cross-sectional view of a skeleton joint having rotational and bending limits in accordance with another embodiment of the present invention; 
       FIG. 5A  is a front view of a skeleton joint similar to that in  FIG. 5  having rotational and bending limits in accordance with another embodiment of the present invention; and 
       FIG. 6  is a side view of a doll/toy having an infrastructure in accordance with the present invention. 
   

   It should be understood that the drawings are for purposes of illustrating the concepts of the invention and are not necessarily the only possible configuration for illustrating the invention. 
   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   The present invention provides infrastructures for toys and/or dolls having a joint or connection, which includes a natural range of motion and flexibility. In one embodiment, a backbone for an infrastructure includes a first compliant member having a first spherical portion formed thereon. An annular ring is formed adjacent to the first spherical structure at or near the connection point between the first spherical portion and the first member. A second member includes a hollow second spherical portion adapted to receive the first spherical member. The second spherical portion is permitted to rotate relative to the first spherical portion, and is limited by the annular ring. Further limitations on the relative motion may include a limit to the relation rotation between the spherical portions. This may be performed by adding tabs and slots in the respective members. In this way, a more natural range of motion is achieved while providing sufficient strength and flexibility in the infrastructure. 
   It is to be understood that the present invention is described in terms of a doll infrastructure. However, the present invention is broader and includes all dolls, stuffed animals, action figures or any other device or toy. 
   Referring now in specific detail to the drawings in which like reference numerals identify similar or identical elements throughout the several views, and initially to FIG.  1 , a skeleton portion or backbone  10  is illustratively depicted for a human doll. Backbone  10  includes connections for arms  12  and legs  14 . Connections for arms  12  and legs  14  are preferably integrally formed with a spine  24 . Connections  12  and  14  may be connected to links (not shown), which may be the same length or variable lengths. Each link may include a ball end and a socket end, which would correspond with a ball end  18  or a socket end  20  on backbone  10 .  FIG. 1  depicts ball ends  18  with a socket end connected to a neck portion  15 . 
   It is preferable that adjacent links are attached by inserting the ball end  18  into the adjacent link&#39;s socket end  20  to achieve a rotatable connection (see also e.g.,  FIG. 6 ). 
   Backbone  10  includes a spine  24 , which connects a shoulder portion  26  to a hip portion  28 . Shoulder portion  26  includes one of a ball end  18  and socket end  20  for each arm  12  and for a neck portion  15 . Hip portion  28  includes one of a ball end  18  and socket end  20  for each leg  14 . It is to be understood that other connectors or joints may be employed in addition to or instead of ball and socket joints. 
   In one embodiment, spine  24  includes a flexible rod. The rod includes a resilient material such as a plastic, which is capable of bending in the direction of arrow “A” into or out of the page and twisting in the direction of arrow “B”. In this way, relative motion is provided between hip portion  28  and shoulder portion  26 , when a force is applied to the skeleton. The flexible spine  24  provides a limited motion for the skeleton and avoids unnatural contortions of the spine  24 , which are prevalent in the prior art. In a particularly useful embodiment, spine  24  includes grooves  34  therein, which are preferably longitudinally oriented (see  FIG. 1A ). These longitudinal grooves  34  provide a reduction in cross-sectional area of spine  24  to permit torsional deflection while maintaining sufficient distances from the neutral axis for portions of the spine  24  such that sufficient bending resistance is maintained. In one embodiment, spine  24  is made from a flexible moldable plastic, such as polypropylene. Other plastics or polymer materials may also be employed. 
   In other embodiments, spine  24  may be made flat or have a cross-section with an aspect ratio to permit easier bending in a single axis while resisting bending in another axis (see  FIG. 1A ). 
   Referring to  FIG. 2 , a spine  124  is provided that includes multiple parts. A shoulder portion  126  is adapted to receive a hip portion  128  (or vice versa) in a socket  133 . Hip portion  128  includes a ball  130  and an annular ring  132  which serves to limit a bending motion of shoulder portion  126  relative to hip portion  128 , but permits rotation of shoulder portion  126  relative to hip portion  128 . In this way, rotational poses may be applied to the doll skeleton. In an alternate embodiment, annual ring  132  may be replaced with a set of pegs, protrusions, a shouldered portion or other increase in width or thickness of the spine portion adjacent to ball  130 . 
   Longitudinal portions  134  and  136  of shoulder  126  and hip portions  128  preferably include longitudinal grooves  34  (as described above with reference to  FIGS. 1 and 1A ). In this case, grooves  34  maintain bending resistance, but only apply torsional resistance when the rotational motion of spine  124  is limited. Limited spine motion will be described below. 
   It is to be noted that ball  130  may include a portion of a ball, as long as the joint provides a ball and socket motion. For example, an upper portion of ball  130  may be left off is that upper portion is not needed for engagement with the socket. 
   Referring to  FIG. 3 , a spine joint  202  includes a ball  204  and a socket  205 . Ball  204  has a ring  206  formed adjacent thereto. Ring  206  may include a plurality of different arrangements. For example, ring  206  may only be formed over a fraction of the circumference of spine  210 . In this way, joint  202  may permit rotation (arrow “D”) as well as a tilt angle (arrow “C”) between spine portions  210  and  212 . 
   In one embodiment, ring  206  exists over a range of the circumference of spine  210  for between about 5 degrees to about 180 degrees. The ring  206  may be oriented to provide a tilting angle “C” to simulate back movements normally permitted by a spine. In addition lateral movements and rotations are permitted. These complex motions can be design into the joint by varying the circumference of spine  210  covered by ring  206 . 
   Referring to  FIGS. 4 and 4A , a rotational limiter  302  is provided on ring  206 . Limiter  302  may include a protrusion or protrusions  304  formed on ring  206  or formed directly on spine. In  FIG. 4 , socket  305  includes an open slot  306  which when assembled on ball  204  permits protrusion  304  to fit therein. Protrusion  304  corresponds to slot  306  and permits rotation between socket  205  and ball  204  until a sidewall  308  of slot  306  is encountered by protrusion  304  during rotation. Once encountered, engagement of protrusion  304  and slot  306  prevent further rotation in the direction that caused engagement between the parts. Likewise, if rotated in the opposite direction, engagement between an opposite sidewall  308  of slot  306  and protrusion  304  will occur thereby limiting relative rotational motion between socket  305  and ball  204 . 
   Slot  306  may extend about the circumference of socket  305  from between about 0 degrees to about 170 degrees. A lower portion  310  of socket  305  should engage ring  206  around ball  204  to permit a stable joint that does not permit tilting between adjacent spine sections  210  and  212 . Motion permitted is rotational as indicated by arrow “F”. 
   Referring to  FIGS. 5 and 5A , a combined joint  402  includes the features described with reference to  FIGS. 3 and 4 . Joint  402  includes an open slot  404 . Slot  404  includes an opening  406  configured to permit an additional range of motion to the joint  402 . In this way, a protrusion or protrusions  408  can be maneuvered in the available space in slot  404  to permit a pre-determined motion for joint  402  in the directions of arrows “G” and “H”. Protrusions  403  and  408  may be formed as a portion of ring  206  as described earlier or may take the form of a geometric shape that provides support as well as limitations on the movement of joint  402 . 
   In one embodiment, protrusion  408  may include rounded edges to permit a smooth engagement with walls  410  of slot  404 . An exemplary embodiment includes slot  404  formed as a complex shape to permit joint  402  to bend forward, say up to about 30 degrees, permit rotation from left to right of about 90 degrees (extreme-to-extreme) about the axis of spine  212 . All other motions of joint  402  are prevented. However, if spine  210  and  212  are formed from a resilient bendable/twistable material then an additional deflection can be temporarily achieved to permit additional motion of the skeleton. 
   It is to be understood that the joints described herein may be employed in any joint of a doll or toy. For example, joint  402  may be employed in a knee joint, elbow joint, ankle joint, neck joint, shoulder joint, tail joint or any other joint. The joints may be employed in any toy, and are particularly useful in toys or dolls where the skeleton is hidden from view by an outer layer of fabric, rubber or other suitable material. 
   Referring to  FIG. 6 , a doll or stuffed animal  500  includes an internal skeleton  502  having joints  504  in accordance with the present invention. Skeleton  500  includes joints  504 , which may include a combination of joints as described above. A covering  508  that may include a fabric, plastic, rubber or other skin or fur-like material covers skeleton  502 . An optional stuffing material  506  may be provided to fill out covering  508 . In addition, spacers or fillers  510  may be employed to further fill out covering  508  or to provide a predetermined shape to doll  500 . Spacers  510  may be attached to skeleton  502  or be permitted to float freely within skeleton  502 . 
   Other features  512  may be attached to skeleton or infrastructure  502 . These features  512  may be internal or external to covering  508 . For example, features  512  may include hands, feet, a head, wings, or other features of the doll or animal  500 . 
   Having described preferred embodiments for doll and infrastructures therein (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments of the invention disclosed which are within the scope and spirit of the invention as outlined by the appended claims. Having thus described the invention with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.