Abstract:
Disclosed is a dual axis of rotation tablet arm storage mechanism. The mechanism includes a first rotor block rotationally secured to a second rotor block. Both rotor blocks travel within a dual walled track of the mechanism. In the use configuration, the walls of the track are adjacent to the second rotor and restrict the rotation of the second rotor to help stabilize the writing surface. While the disclosed tablet arm maintains the benefits of other tablet arm mechanisms, many other benefits are achieved such as a mechanism that is free of pinch points during operation. The disclosed mechanism includes a dual access rotation mechanism that also allows the elevational alignment of the tablet top surface to be adjusted while the table top is in use.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to multi-configuration table top surfaces and more particularly to storable tablet surfaces secured to chairs. 
       BACKGROUND OF THE INVENTION 
       [0002]    Storable writing surfaces secured to furniture have been the subject of numerous patents, such as Chancey Sherman&#39;s 1867 Letters U.S. Pat. No. 68,659, however the mechanisms disclosed in these references typically have numerous pinch points that could injure a child who sticks their fingers into the mechanism as it is operated. As a result, storable desk tops attached to chairs are rarely used in the early school years. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention provides an improved tablet arm rotation mechanism. While the present invention maintains the benefits of other tablet arm mechanisms, many other benefits are also achieved such as a mechanism that is free of pinch points during operation. The disclosed invention includes a dual axis rotation mechanism that also allows the elevational alignment of the tablet top surface to be adjusted while the table top is in use. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a lower perspective view of a tablet arm mechanism in a use configuration. 
           [0005]      FIG. 2  is a side elevational view of the tablet arm mechanism in a use configuration. 
           [0006]      FIG. 3  is an upper perspective view of a tablet arm mechanism in a storage configuration attached to a chair. 
           [0007]      FIG. 4  is an upper perspective view of a tablet arm mechanism attached to a chair and in the first step of transitioning from a storage configuration to a use configuration. 
           [0008]      FIG. 5  is an upper perspective view of a tablet arm mechanism attached to a chair and in the second step of transitioning from a storage configuration to a use configuration. 
           [0009]      FIG. 6  is an upper perspective view of a tablet arm mechanism attached to a chair and in a use configuration. 
           [0010]      FIG. 7  is a side perspective view of a tablet arm mechanism in a storage configuration. 
           [0011]      FIG. 8  is a front elevational view of a tablet arm mechanism in a storage configuration. 
           [0012]      FIG. 9  is a side elevational view of a tablet arm mechanism in a storage configuration. 
           [0013]      FIG. 10  is a side perspective view of a tablet arm mechanism in a first transition stage. 
           [0014]      FIG. 11  is a side elevational view of a tablet arm mechanism in a first transition stage. 
           [0015]      FIG. 12  is a front elevational view of a tablet arm mechanism in a first transition stage. 
           [0016]      FIG. 13  is a side perspective view of a tablet arm mechanism in a second transition stage. 
           [0017]      FIG. 14  is a side elevational view of a tablet arm mechanism in a second transition stage. 
           [0018]      FIG. 15  is a front elevational view of a tablet arm mechanism in a second transition stage. 
           [0019]      FIG. 16  is a side perspective view of a tablet arm mechanism in a use configuration. 
           [0020]      FIG. 17  is a side elevational view of a tablet arm mechanism in a use configuration. 
           [0021]      FIG. 18  shows an isolated view of a first rotor block and a second rotor block. 
           [0022]      FIG. 19  shows an isolated bottom plan view of a second rotor block. 
           [0023]      FIG. 20  shows a side-elevational cross-sectional view of a tablet arm mechanism in a storage configuration. 
           [0024]      FIG. 21  shows a side-elevational cross-sectional view of a tablet arm mechanism in a use configuration. 
           [0025]      FIG. 22  shows a lower perspective view of an exploded tablet arm mechanism. 
           [0026]      FIG. 23  shows an upper perspective view of an exploded tablet arm mechanism. 
           [0027]      FIG. 24  shows a side elevational view of an exploded tablet arm mechanism. 
           [0028]      FIG. 25  shows a front elevational view of an exploded tablet arm mechanism. 
           [0029]      FIG. 26  shows a front perspective view of a second exploded tablet arm mechanism. 
           [0030]      FIG. 27  shows a rear perspective view of a second exploded tablet arm mechanism. 
           [0031]      FIG. 28  shows an upper perspective view of a second exploded tablet arm mechanism. 
           [0032]      FIG. 29  shows a side elevational view of a second exploded tablet arm mechanism. 
           [0033]      FIG. 30  is an upper perspective view of a tablet arm mechanism in an auxiliary configuration while attached to a chair. 
           [0034]      FIG. 31  is a cross sectional view of a tablet arm mechanism with a downwardly angled tablet plate. 
           [0035]      FIG. 32  is a cross sectional view of a tablet arm mechanism with a level tablet plate. 
           [0036]      FIG. 33  is a cross sectional view of a tablet arm mechanism with an upwardly angled tablet plate. 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    The present invention may be used with any planar surface that is secured to a post and rotated from a vertical storage configuration to a horizontal use configuration. However, for descriptive purposes, the present invention will be described as in use as a tablet arm mechanism attached to a chair. 
         [0038]      FIG. 1  shows a tablet arm mechanism  10  with a connector piece  15  extending between a first side piece  20  and a second side piece  25 . The first side piece, the second side piece, and the connector piece form a base that can be secured to a seat. Rotationally secured between the first side piece  20  and the second side piece  25  is a first rotor block  30 . Rotationally secured to the first rotor block  30  is a second rotor block  35  that rotates relative to the first rotor block  30 . A tablet top may be secured directly to the second rotor block  35 , or a tablet plate  40  or tablet connection plate may be secured onto the second rotor block  35  to better support the load of the table top. 
         [0039]    The first side piece  20  includes a first wall  45  that is located a first distance  50  from a second wall  55  of the second side piece  25 . As can be seen in  FIG. 2 , the widths of both the connector piece  15  and the first rotor block  30  are substantially equal to the separation of the first wall  45  from the second wall  55 . While there may be minor gaps between the first rotor block  30  and the two walls ( 45 ,  55 ), it is expected that the tablet arm mechanism may be used in seating for young children and the gaps would be of insufficient size to allow children to put their fingers in the gaps. 
         [0040]    The first rotor block  30  rotates about a first axis of rotation  60  that is substantially perpendicular to both the first wall  45  and the second wall  55 . Each of the side pieces ( 20 ,  25 ) has an aperture ( 65 ,  70 ) that defines a channel  75  that extends parallel to the first axis of rotation  60 . The channel  75  is configured to clamp around the arm of a chair as shown in  FIGS. 3 through 6 . Since it is generally expected that the tablet arm mechanism will be clamped onto a horizontal chair arm, it is also expected that rotation of the first rotor block  35  will cause the tablet plate  40  to vertically adjust. 
         [0041]    As can be seen in  FIG. 2 , when the tablet arm mechanism is in a use configuration a portion of the second rotor block  35  is also directly located between both the first wall  45  and the second wall  55 . Additionally, like the first rotor block  30 , the second rotor block  35  has a width that is substantially equal to the first distance. The second rotor block  35  rotates about a second axis of rotation  65  relative to the first rotor block  30 . The second axis of rotation  65  is perpendicular to the first axis of rotation  60 , and in the illustrated example the first axis of rotation  60  is both always perpendicular and intersecting with the second axis of rotation  65 . While the second axis of rotation  65  is stationary relative to the first rotor block  30 , it should be appreciated that since the first rotor block  30  rotates relative to the chair, the second axis of rotation  65  moves with the first rotor block  30 . This movement is highlighted in  FIGS. 20 and 21 . 
         [0042]      FIGS. 3 through 6  illustrate how the first rotor block  30  and the second rotor block  35  operate in combination to move a table surface from a vertical storage configuration to a horizontally oriented use configuration. In  FIG. 3 , the tablet plate  40  is shown as substantially vertical with the distant end  80  located below the rotor end  85  of the tablet plate  40 . Moving from  FIG. 3  to  FIG. 4 , the second rotor block  35  is rotated until the distant end  80  and rotor end  85  of the tablet plate  40  are located at the same elevation. In  FIG. 5 , the second rotor block has rotated 180 degrees from the configuration shown in  FIG. 3  and the distant end  85  is located directly above the rotor end  85 .  FIG. 5  also shows the tablet arm mechanism with an additional table top attached to the tablet plate. In the transition from the configuration shown in  FIG. 3  to that of  FIG. 5 , the second rotor block  35  is rotating while the first rotor block  30  is substantially stationary. The first rotor block  30  may rotate a trivial amount, but the tablet plate  40  remains vertically oriented. Once the second rotor block  35  reaches the configuration shown in  FIG. 5 , the first rotor block  30  is allowed to rotate the tablet plate from the vertical orientation shown in  FIG. 5  to the horizontal orientation shown in  FIG. 6 . The second rotor block has a second width that is greater than the first distance and acts to block the second rotor block from entering the track between the first wall and the second wall while the tablet arm mechanism is in the configuration shown in  FIG. 4 . 
         [0043]      FIGS. 7 through 9  show an isolated view of the tablet arm mechanism  10  in the storage configuration shown in  FIG. 3 . As can be seen in  FIG. 7 , the first rotor block  30  has a cylindrical portion  90  and a block portion  95  that is connected to the second rotor block  35 . The cylindrical portion  90  is concentric around the first axis of rotation  60  such that as the first rotor block  30  rotates it is kept at a constant small separation from the connector piece  15 . By maintaining a constant minimally small separation, the chances of a young child having their fingers pinched during operation of the mechanism is substantially reduced.  FIG. 7  also highlights the first wall  45  of the first side piece  20 . As can be seen in  FIG. 7 , the first wall  45  is asymmetric about the first axis of rotation  60 . Shown in  FIG. 8 , the first wall  45  extends a horizontal distance  100  from the first axis of rotation  60 , a vertical distance  105  from the first axis of rotation  60 , and the vertical distance  105  is greater than the horizontal distance  100 . In  FIG. 8 , the second rotor block  35  is shown having a first height  133  parallel to the second axis of rotation. The tablet plate is secured to the second rotor block and is separated from the first rotor block by the first height  133 . 
         [0044]    The first wall  45  need not be made from a single unit. As shown in  FIGS. 7 and 8 , the first wall  45  is constructed from a first block of metal  110  and a second block of metal  115 . Other materials that could be used in the construction of the tablet mechanism include wood and polymers. 
         [0045]    Highlighted in  FIGS. 8 and 9 , the second rotor block  35  has a first flat side  120  and a second flat side  125  (not shown in  FIGS. 8 and 9 ) that are parallel to each other and both extend from a first convex side  130  to a second convex side  135 . The flat sides ( 120 ,  125 ) are separated from each other by approximately the first distance  50  and are of sufficient rigidity to prevent rotation of the second rotor block  35  relative to the first rotor block  30  when the tablet mechanism is in the use configuration with the tablet plate  50  horizontally oriented. While the flat sides ( 120 ,  125 ) act to inhibit rotation when the tablet arm mechanism is in the use configuration, the shape of the convex sides ( 130 ,  135 ) helps to prevent the creation of pinch points as the second rotor block  35  is rotated about the second axis of rotation. While it is contemplated that a second rotor block  35  could have four flat sides arranged in a rectangular configuration, utilization of four flat sides could create a pinch point between the second rotor block and the first block of metal  110  when the second rotor block is rotated. 
         [0046]    In addition to the first flat side  120  and the second flat side  125 , the illustrated second rotor block  35  has a flat rotation side  140  which is directly adjacent to a flat side of the cylindrical portion  90  of the first rotor block  30 . As with many of the features of the tablet mechanism, in the embodiment shown there is only a minimal gap between the flat rotation side  140  and the first rotor block  30  such that a small child using the tablet mechanism would not be able to pinch their fingers between the first and second rotor blocks. 
         [0047]      FIGS. 10 through 12  show isolated views of the tablet mechanism in the configuration shown in  FIG. 4 . The second flat side  125  of the second rotor block  35  which was not visible in  FIGS. 8 and 9  is shown in  FIGS. 10 through 12 . Highlighted in  FIG. 12 , there is a slight gap  145  between the flat rotation side  140  of the rotation mechanism and the curved outer wall  150  which allows for rotation of the second rotor block  35  about the second axis of rotation when the tablet plate is in a vertical orientation. On the curved inner wall  155  of the tablet mechanism, there is a concave region  160  which acts as an arm rest when the tablet arm mechanism is in the storage configuration. 
         [0048]      FIGS. 13 through 15  show the isolated tablet arm mechanism in the configuration shown in  FIG. 5 . While not contacting each other, the second flat side  125  of the second rotor block  35  is nearly coplanar with the first wall  45  of the first side piece  20  and the first flat side  120  of the second rotor  35  is nearly coplanar with the second wall  55  of the second side piece  25 . The first wall  45  and the second wall  55  form a track in which the first and second rotor blocks ( 30 ,  35 ) travel when the first rotor block is rotated. 
         [0049]      FIGS. 16 and 17  show an isolated tablet arm mechanism in the use configuration shown in  FIG. 6  where the main surface  165  of the tablet plate  40  is horizontally aligned. In the configuration shown, the first wall  45  is aligned with and directly adjacent to the first flat wall  125  of the second rotor block  35 . The second wall  55  is directly adjacent to the second flat wall  130  of the second rotor block  35 . The interaction of the adjacent walls acts to limit the rotation of the second rotor block relative to the first rotor block about the second axis or rotation  65 . When the mechanism is in the configuration shown in  FIG. 6 , if the second rotor rotates slightly, a portion of the first wall will contact the second rotor block, a portion of the second wall will also contact the second rotor block and rotation will be inhibited. The tablet plate  40  (and the optional table top mounted on the table plate) provide a substantial amount of leverage that can be applied to the second rotor block. It is expected that the tablet arm mechanism will be used in challenging environments, such as high schools, so the inventor contemplates the adjacent walls will be constructed from highly resilient material, such as hardened metals or a reinforced material. As shown in  FIGS. 8 ,  12 ,  15 , and  17 , the tablet plate  40  is always distant from both the first wall  45  and the second wall  55  in the illustrated example. 
         [0050]      FIG. 18  shows an isolated view of the first rotor block  30  and the second rotor block  35 . The first rotor block  30  includes a cylindrical portion  90  and a block portion  95 , at the intersection of the cylindrical portion  90  with the block portion, a first dowel  170  extends from a first side  175  of the first rotor block  30  while a second dowel  180  extends away from the first dowel at the second side  185  of the first rotor block  30 . In the illustrated example, the lengths of the dowels are substantially equal to the widths of the first and second side pieces. However, it should be appreciated that in some embodiments the dowels will be longer or shorter than the side pieces. It should also be appreciated that in alternate embodiments other devices or features will be used to rotatably secure the first rotor block between the first and second walls. The inventor also contemplates using shoulder bolts for the rotatable connections. In one example, the lengths of the dowels are less than the width of the side pieces ( 20 ,  25 ) such that the dowels are not readily visible when the tablet mechanism  10  has been fully assembled. The side pieces ( 20 ,  25 ) may have walls that abut with the ends of the dowels such that the dowels are completely hidden when the tablet mechanism is fully assembled. Extending from each of the dowels is a rotation limiter  190  that acts to restrict the rotation of the first rotor block  30  about the first axis of rotation  60 . In the illustrated example, the rotation limiters  190  are roughly in the shape of a wedge however other shapes, such as a cylindrical pin or a rectangular box extending away from the dowel ( 170 ,  180 ) perpendicular to the first axis of rotation  60  may also be used. In an exemplary embodiment, screws extend through the first and second side pieces ( 20 ,  25 ) into the track in which the rotation limiter travels, by decreasing the size of the rotation limiter&#39;s track, the mechanism can be adjusted such that the tablet plate is level when the tablet mechanism is in the use configuration. See  FIG. 27 , for further details. 
         [0051]    The block portion  90  has a rotor surface  187  adjacent to the second rotor block  35  that includes a semi-circular track  195  and a cylindrical hole  200 . The second rotor  35  includes a center pin  205  aligned with the second axis of rotation and adapted to be secured within the cylindrical hole  200  of the first rotor block  30 . The rotation pin  210  extends parallel to the center pin  205  and is configured to travel within the semi-circular track  195  of the first rotor block  30 . As with the rotation limiters on the dowels ( 170 ,  180 ), the rotation pin  210  acts to limit the rotation of the second rotor block  35  about the second axis of rotation. In the illustrated example, the rotation limiters  190  on the dowels ( 170 ,  180 ) limit the rotation about the first axis of rotation  60  to approximately 90 degrees while the rotation pin  210  on the second rotor block  35  limits the rotation about the second axis of rotation to about 180 degrees. Transitioning from the configuration shown in  FIG. 3  to the configuration shown in  FIG. 5  the second rotor block rotates approximately 180 degrees. 
         [0052]    While the second rotor block is shown with a rotation limiting pin and the first rotor block has wedge shaped structures, it should be appreciated that the type of rotation limiters may be switched between the rotors, or both rotor blocks may use wedges or both rotor blocks may use pins to limit rotation. The center pin of the second rotor block may be in the form of a screw or other fastener that extends fully through both the first rotor block  30  and the second rotor block  35 . 
         [0053]      FIG. 19  shows a bottom view of the second rotor block  35 . The second rotor block has a first width  215  and a second width  220  that are both perpendicular to the second axis of rotation  65 . The first width extends from the first convex surface  130  to the second convex surface  135  while the second width extends from the first flat side  120  to the second flat side  125 . The second width  220  is substantially equal to the separation of the first wall  45  from the second wall  55  (the first distance  50 ), while the first width  215  is substantially greater than the second width  220 . The second rotor block  35  is rotatable to a configuration where the first width  215  is parallel to the first axis of rotation (see  FIG. 4 ). Since the first width  215  is greater than the first distance  50 , the second rotor block  35  is prevented from moving directly between the first wall  45  and the second wall  55  which effectively inhibits rotation of the first rotor block about the first axis of rotation. With the exception of the pin, the illustrated second rotor block  35  is symmetric about the first width  215  and the second width  220  measured through the second axis of rotation  65 . 
         [0054]      FIGS. 20 and 21  show cross sectional views of the first rotor block  30  in both a storage configuration ( FIG. 20 ) and a use configuration ( FIG. 21 ). These figures highlight how in the storage configuration, the first rotor block  30  extends along the second axis of rotation  65  from the first axis of rotation  60  beyond a portion of the first wall  45  (not shown) and the second wall  55  to the rotor surface  187 . With the first rotor block extending past the curved first and second walls ( 45 ,  55 ) and the curved outer walls  150  of the side pieces, the second rotor block  35  is able to rotate about the second axis of rotation  65 . In the use configuration, the first and second walls ( 45 ,  55 ) extend adjacent to the first rotor block away from the first axis of rotation  60  parallel to the second axis of rotation  65  past the rotor surface  187  of the first rotor block  30 . The portions  225  of the first and second walls ( 45 ,  55 ) that extend from the rotor surface  187 , away from the first axis of rotation  60  parallel to the second axis of rotation  65  act to rotationally lock the second rotor block  35  when the tablet mechanism  10  is in the use configuration. As with the flat sidewalls of the second rotor block  35 , the portions  225  of the first and second walls ( 45 ,  55 ) that rotationally lock the second rotor block  35  may be reinforced with resilient materials. 
         [0055]      FIGS. 22 through 25  show an embodiment of the tablet arm with eight separable components. In the illustrated example, each of the side pieces ( 45 ,  55 ) is constructed from two blocks that are secured together with fasteners. Between the two side pieces is the connector piece  15 . Best illustrated in  FIGS. 20 ,  21 , and  25 , the connector piece  15  has a first edge  230  and a second edge  235  that both fully extend from the first wall  45  of the first side piece  20  and the second wall  55  of the second side piece  25 . Between the two edges ( 230 ,  235 ) the connector piece  15  has a concave surface  240  that extends between the two edges. The concave surface  240  is substantially defined by the cylindrical portion  90  of the first rotor block  30  and is approximately concentric with the first axis of rotation  60 . 
         [0056]      FIGS. 26 through 29  show an alternate embodiment of the tablet arm mechanism  10  with five separable components. In this embodiment, a first and second block ( 245 ,  250 ) each form half of each side piece ( 20 ,  25 ) and the connector piece  15 . Despite being formed from two components, the connector piece  15  includes two edges ( 230 ,  235 ) that fully extend from the first wall  45  to the second wall  55  parallel to the first axis of rotation. Additionally, the connector piece  15  has a concave surface  240  (made from two unique blocks of metal) that extends between the two edges ( 230 ,  235 ). As with the first wall and the second wall of the side pieces, it should be appreciated that the walls ( 45 ,  55 ) need not be formed from a single construction.  FIG. 27  shows the track  255  in which the rotation restrictors  190  of the dowels ( 170 ,  180 ) rotate.  FIG. 27  also shows holes  260  through both the first side piece  20  and the second side piece  25 . In order to provide a level tablet surface when the mechanism is in the use configuration, a user may advance screws through those holes which will limit how far the first rotor block  30  is able to rotate.  FIG. 27  also illustrates the channel  75  in the side pieces and connector piece that is used to clamp onto chairs or other furniture. The two side pieces ( 20 ,  25 ) and the connector piece  15  each have apertures that form the channel parallel to the first axis of rotation. As can be seen in  FIGS. 26 through 29 , the term “piece” is not limited to individually separable components and includes portions of a single object. 
         [0057]      FIG. 30  shows the mechanism in an auxiliary configuration that is achieved by rotating the first rotor block while the mechanism is in the configuration shown in  FIG. 3 . In the auxiliary configuration, the second flat side  125  of the second rotor block  35  is substantially coplanar with and directly adjacent to the second wall  55  of the second side piece  25 . The first flat side  120  is substantially coplanar with and directly adjacent to the first wall  45  of the first side piece  20 . 
         [0058]      FIG. 31 through 33  illustrate a tablet arm mechanism that is leveled based on a screw  265  passing through holes  260  and pressing against a rotation limiter  190 . As the screw  265  is rotated through the hole it extends out and hits the rotation limiter  190  which decreases the amount that first rotor block  30  is able to rotate. By limiting the rotation of the first rotor block  30 , the angle of the table top relative to horizontal may be adjusted. 
         [0059]    The inventor contemplates several alterations and improvements to the disclosed invention. Other alterations, variations, and combinations are possible that fall within the scope of the present invention. Although various embodiments of the present invention have been described, those skilled in the art will recognize more modifications that may be made that would nonetheless fall within the scope of the present invention. Therefore, the present invention should not be limited to the apparatus described.