Tablet arm mechanism

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.

FIELD OF THE INVENTION

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

Storable writing surfaces secured to furniture have been the subject of numerous patents, such as Chancey Sherman'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

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.

DETAILED DESCRIPTION

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.

FIG. 1shows a tablet arm mechanism10with a connector piece15extending between a first side piece20and a second side piece25. 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 piece20and the second side piece25is a first rotor block30. Rotationally secured to the first rotor block30is a second rotor block35that rotates relative to the first rotor block30. A tablet top may be secured directly to the second rotor block35, or a tablet plate40or tablet connection plate may be secured onto the second rotor block35to better support the load of the table top.

The first side piece20includes a first wall45that is located a first distance50from a second wall55of the second side piece25. As can be seen inFIG. 2, the widths of both the connector piece15and the first rotor block30are substantially equal to the separation of the first wall45from the second wall55. While there may be minor gaps between the first rotor block30and 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.

The first rotor block30rotates about a first axis of rotation60that is substantially perpendicular to both the first wall45and the second wall55. Each of the side pieces (20,25) has an aperture (65,70) that defines a channel75that extends parallel to the first axis of rotation60. The channel75is configured to clamp around the arm of a chair as shown inFIGS. 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 block35will cause the tablet plate40to vertically adjust.

As can be seen inFIG. 2, when the tablet arm mechanism is in a use configuration a portion of the second rotor block35is also directly located between both the first wall45and the second wall55. Additionally, like the first rotor block30, the second rotor block35has a width that is substantially equal to the first distance. The second rotor block35rotates about a second axis of rotation65relative to the first rotor block30. The second axis of rotation65is perpendicular to the first axis of rotation60, and in the illustrated example the first axis of rotation60is both always perpendicular and intersecting with the second axis of rotation65. While the second axis of rotation65is stationary relative to the first rotor block30, it should be appreciated that since the first rotor block30rotates relative to the chair, the second axis of rotation65moves with the first rotor block30. This movement is highlighted inFIGS. 20 and 21.

FIGS. 3 through 6illustrate how the first rotor block30and the second rotor block35operate in combination to move a table surface from a vertical storage configuration to a horizontally oriented use configuration. InFIG. 3, the tablet plate40is shown as substantially vertical with the distant end80located below the rotor end85of the tablet plate40. Moving fromFIG. 3toFIG. 4, the second rotor block35is rotated until the distant end80and rotor end85of the tablet plate40are located at the same elevation. InFIG. 5, the second rotor block has rotated 180 degrees from the configuration shown inFIG. 3and the distant end85is located directly above the rotor end85.FIG. 5also shows the tablet arm mechanism with an additional table top attached to the tablet plate. In the transition from the configuration shown inFIG. 3to that ofFIG. 5, the second rotor block35is rotating while the first rotor block30is substantially stationary. The first rotor block30may rotate a trivial amount, but the tablet plate40remains vertically oriented. Once the second rotor block35reaches the configuration shown inFIG. 5, the first rotor block30is allowed to rotate the tablet plate from the vertical orientation shown inFIG. 5to the horizontal orientation shown inFIG. 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 inFIG. 4.

FIGS. 7 through 9show an isolated view of the tablet arm mechanism10in the storage configuration shown inFIG. 3. As can be seen inFIG. 7, the first rotor block30has a cylindrical portion90and a block portion95that is connected to the second rotor block35. The cylindrical portion90is concentric around the first axis of rotation60such that as the first rotor block30rotates it is kept at a constant small separation from the connector piece15. 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. 7also highlights the first wall45of the first side piece20. As can be seen inFIG. 7, the first wall45is asymmetric about the first axis of rotation60. Shown inFIG. 8, the first wall45extends a horizontal distance100from the first axis of rotation60, a vertical distance105from the first axis of rotation60, and the vertical distance105is greater than the horizontal distance100. InFIG. 8, the second rotor block35is shown having a first height133parallel 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 height133.

The first wall45need not be made from a single unit. As shown inFIGS. 7 and 8, the first wall45is constructed from a first block of metal110and a second block of metal115. Other materials that could be used in the construction of the tablet mechanism include wood and polymers.

Highlighted inFIGS. 8 and 9, the second rotor block35has a first flat side120and a second flat side125(not shown inFIGS. 8 and 9) that are parallel to each other and both extend from a first convex side130to a second convex side135. The flat sides (120,125) are separated from each other by approximately the first distance50and are of sufficient rigidity to prevent rotation of the second rotor block35relative to the first rotor block30when the tablet mechanism is in the use configuration with the tablet plate50horizontally 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 block35is rotated about the second axis of rotation. While it is contemplated that a second rotor block35could 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 metal110when the second rotor block is rotated.

In addition to the first flat side120and the second flat side125, the illustrated second rotor block35has a flat rotation side140which is directly adjacent to a flat side of the cylindrical portion90of the first rotor block30. As with many of the features of the tablet mechanism, in the embodiment shown there is only a minimal gap between the flat rotation side140and the first rotor block30such that a small child using the tablet mechanism would not be able to pinch their fingers between the first and second rotor blocks.

FIGS. 10 through 12show isolated views of the tablet mechanism in the configuration shown inFIG. 4. The second flat side125of the second rotor block35which was not visible inFIGS. 8 and 9is shown inFIGS. 10 through 12. Highlighted inFIG. 12, there is a slight gap145between the flat rotation side140of the rotation mechanism and the curved outer wall150which allows for rotation of the second rotor block35about the second axis of rotation when the tablet plate is in a vertical orientation. On the curved inner wall155of the tablet mechanism, there is a concave region160which acts as an arm rest when the tablet arm mechanism is in the storage configuration.

FIGS. 13 through 15show the isolated tablet arm mechanism in the configuration shown inFIG. 5. While not contacting each other, the second flat side125of the second rotor block35is nearly coplanar with the first wall45of the first side piece20and the first flat side120of the second rotor35is nearly coplanar with the second wall55of the second side piece25. The first wall45and the second wall55form a track in which the first and second rotor blocks (30,35) travel when the first rotor block is rotated.

FIGS. 16 and 17show an isolated tablet arm mechanism in the use configuration shown inFIG. 6where the main surface165of the tablet plate40is horizontally aligned. In the configuration shown, the first wall45is aligned with and directly adjacent to the first flat wall125of the second rotor block35. The second wall55is directly adjacent to the second flat wall130of the second rotor block35. 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 rotation65. When the mechanism is in the configuration shown inFIG. 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 plate40(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 inFIGS. 8, 12, 15, and 17, the tablet plate40is always distant from both the first wall45and the second wall55in the illustrated example.

FIG. 18shows an isolated view of the first rotor block30and the second rotor block35. The first rotor block30includes a cylindrical portion90and a block portion95, at the intersection of the cylindrical portion90with the block portion, a first dowel170extends from a first side175of the first rotor block30while a second dowel180extends away from the first dowel at the second side185of the first rotor block30. 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 mechanism10has 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 limiter190that acts to restrict the rotation of the first rotor block30about the first axis of rotation60. In the illustrated example, the rotation limiters190are 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 rotation60may 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's track, the mechanism can be adjusted such that the tablet plate is level when the tablet mechanism is in the use configuration. SeeFIG. 27, for further details.

The block portion90has a rotor surface187adjacent to the second rotor block35that includes a semi-circular track195and a cylindrical hole200. The second rotor35includes a center pin205aligned with the second axis of rotation and adapted to be secured within the cylindrical hole200of the first rotor block30. The rotation pin210extends parallel to the center pin205and is configured to travel within the semi-circular track195of the first rotor block30. As with the rotation limiters on the dowels (170,180), the rotation pin210acts to limit the rotation of the second rotor block35about the second axis of rotation. In the illustrated example, the rotation limiters190on the dowels (170,180) limit the rotation about the first axis of rotation60to approximately 90 degrees while the rotation pin210on the second rotor block35limits the rotation about the second axis of rotation to about 180 degrees. Transitioning from the configuration shown inFIG. 3to the configuration shown inFIG. 5the second rotor block rotates approximately 180 degrees.

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 block30and the second rotor block35.

FIG. 19shows a bottom view of the second rotor block35. The second rotor block has a first width215and a second width220that are both perpendicular to the second axis of rotation65. The first width extends from the first convex surface130to the second convex surface135while the second width extends from the first flat side120to the second flat side125. The second width220is substantially equal to the separation of the first wall45from the second wall55(the first distance50), while the first width215is substantially greater than the second width220. The second rotor block35is rotatable to a configuration where the first width215is parallel to the first axis of rotation (seeFIG. 4). Since the first width215is greater than the first distance50, the second rotor block35is prevented from moving directly between the first wall45and the second wall55which effectively inhibits rotation of the first rotor block about the first axis of rotation. With the exception of the pin, the illustrated second rotor block35is symmetric about the first width215and the second width220measured through the second axis of rotation65.

FIGS. 20 and 21show cross sectional views of the first rotor block30in both a storage configuration (FIG. 20) and a use configuration (FIG. 21). These figures highlight how in the storage configuration, the first rotor block30extends along the second axis of rotation65from the first axis of rotation60beyond a portion of the first wall45(not shown) and the second wall55to the rotor surface187. With the first rotor block extending past the curved first and second walls (45,55) and the curved outer walls150of the side pieces, the second rotor block35is able to rotate about the second axis of rotation65. In the use configuration, the first and second walls (45,55) extend adjacent to the first rotor block away from the first axis of rotation60parallel to the second axis of rotation65past the rotor surface187of the first rotor block30. The portions225of the first and second walls (45,55) that extend from the rotor surface187, away from the first axis of rotation60parallel to the second axis of rotation65act to rotationally lock the second rotor block35when the tablet mechanism10is in the use configuration. As with the flat sidewalls of the second rotor block35, the portions225of the first and second walls (45,55) that rotationally lock the second rotor block35may be reinforced with resilient materials.

FIGS. 22 through 25show 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 piece15. Best illustrated inFIGS. 20, 21, and 25, the connector piece15has a first edge230and a second edge235that both fully extend from the first wall45of the first side piece20and the second wall55of the second side piece25. Between the two edges (230,235) the connector piece15has a concave surface240that extends between the two edges. The concave surface240is substantially defined by the cylindrical portion90of the first rotor block30and is approximately concentric with the first axis of rotation60.

FIGS. 26 through 29show an alternate embodiment of the tablet arm mechanism10with 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 piece15. Despite being formed from two components, the connector piece15includes two edges (230,235) that fully extend from the first wall45to the second wall55parallel to the first axis of rotation. Additionally, the connector piece15has a concave surface240(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. 27shows the track255in which the rotation restrictors190of the dowels (170,180) rotate.FIG. 27also shows holes260through both the first side piece20and the second side piece25. 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 block30is able to rotate.FIG. 27also illustrates the channel75in 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 piece15each have apertures that form the channel parallel to the first axis of rotation. As can be seen inFIGS. 26 through 29, the term “piece” is not limited to individually separable components and includes portions of a single object.

FIG. 30shows the mechanism in an auxiliary configuration that is achieved by rotating the first rotor block while the mechanism is in the configuration shown inFIG. 3. In the auxiliary configuration, the second flat side125of the second rotor block35is substantially coplanar with and directly adjacent to the second wall55of the second side piece25. The first flat side120is substantially coplanar with and directly adjacent to the first wall45of the first side piece20.

FIG. 31 through 33illustrate a tablet arm mechanism that is leveled based on a screw265passing through holes260and pressing against a rotation limiter190. As the screw265is rotated through the hole it extends out and hits the rotation limiter190which decreases the amount that first rotor block30is able to rotate. By limiting the rotation of the first rotor block30, the angle of the table top relative to horizontal may be adjusted.

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.