Abstract:
A mechanism and method for storing and deploying an expansion portion of a surface is provided. The mechanism is configured so as to raise and lower a storable expansion surface portion with respect to an adjacent surface portion, allowing the storable expansion surface portion to be stored behind the adjacent surface portion when a smaller surface area is desired.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a mechanism for mechanically expanding surface areas. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to making surfaces expandable—such as tabletops, whiteboards and blackboards, counters, podiums, platforms, and the like, where it is desired to have a plurality of surface area sizes and ease of change between smaller and lager surface areas is desirable. For purposes of example only, and not by way of limitation, the invention will be described in connection with one application, specifically: a table top. However the invention is applicable more broadly. 
       SUMMARY OF THE INVENTION 
       [0003]    The mechanism is configured so as to raise and lower a storable expansion surface portion with respect to an adjacent surface portion, allowing the storable expansion surface portion to be stored behind the adjacent surface portion when a smaller surface area is desired; and which brings the expansion surface portion forward so as to be coplanar with the adjacent surface portion when the adjacent surface portion is moved laterally outward, and allow the expansion surface portion and the adjacent surface portion to be positioned contiguously, thus enlarging the surface area by the area of the expansion surface area when desired. In one example, two adjacent surface portions which can be provided, comprising table surface portions at least one of which can be moved laterally, and the storable expansion portion can be moved forward into a use position coplanar with them, thus acting to add an extra table leaf in the center of the table. When at least one of the adjacent surface areas is moved inwardly, the storable expansion surface portion moves rearward to a storage position behind the adjacent surface portions. In one example this mechanism allows at least one of the adjacent surface portions to be moved into and out of position contiguous with the storable expansion surface portion when it is in the use position. This motion either creates a detent effect to hold said at least one adjacent surface in position contiguous with the storable expansion surface portion when the adjacent surface is moved toward the storable expansion surface portion while it is in the use position, or to reorder the mechanism to retract the storable expansion surface portion when the adjacent surface portion is moved outward away from said position contiguous with and beside the storable expansion portion in the use position. In the latter case when the adjacent surface portion is thereafter moved toward the storable expansion surface portion the storable expansion surface portion moves rearward with respect to the adjacent surface portions to a storage position behind them. This allows at least one of the adjacent surface portions to close over the storable expansion surface portion and move to a position coplanar with, and contiguous to, the other adjacent surface portion, thus shrinking the surface area by the area of the storable expansion surface portion. 
         [0004]    The above-described features and advantages of the present invention, as well as additional features and advantages, will be set forth or will become more fully apparent in the description that follows. Furthermore, the features and advantages of the invention may be learned by the practice of the invention, or will be obvious to one skilled in the art after referring to the invention description, as set forth hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    Various embodiments of the present invention are shown and described in reference to the numbered drawing wherein: 
           [0006]      FIG. 1  is an exploded view of an embodiment in an expandable table, certain details being excluded for clarity of presentation, i.e. certain elements on the far side of the table in the figure are omitted for sake of clarity, being mirror image identical in nature and position to elements shown on the near side, as well as pulleys and related structure pertinent to expanding the table top being omitted (it is shown in  FIG. 3 ), details of the mechanism shown in other figures are also omitted here in order to present the overall scheme more clearly; 
           [0007]      FIG. 2  is a more detailed exploded view of a surface expansion mechanism portion in one example embodiment; 
           [0008]      FIG. 3  is a more detailed bottom left isometric view of a pulley system for expanding/contracting the surface area of the table by moving one of two adjacent table surface area end elements; 
           [0009]      FIG. 3A  is a more detailed bottom left isometric view of a rack and pinion system for expanding/contracting the surface area of the table by moving one of two adjacent table surface area end elements; 
           [0010]      FIG. 4  is a cross-sectional view, taken along line  4 - 4  in  FIG. 1  of the illustrated elements in unexploded configuration; 
           [0011]      FIG. 5   a - g  is a series of elevational views of the relevant portions of the surface expansion mechanism with the order of elements altered for clarity of presentation (the reversing lever is shown behind the gate/guide/bridge element when it would actually be in front in the view), showing the interplay of the elements thereof in operation in expanding and contracting the surface area of the table via opening and closing the adjacent surface area table end elements, causing the storable expansion surface area table leaf portion to be raised and lowered, and more particularly showing the operation of a gate/guide bridge element in directing the path of an idler attached to the storable expansion surface table leaf portion just mentioned in raising and lowering same as the adjacent surface area table end portions are moved inward and outward in the illustrated example embodiment; 
           [0012]      FIG. 6  is a side-by side comparison exploded view of two example variations of the illustrated embodiment mechanism example; and 
           [0013]      FIG. 7   a - h  is a series of elevational views, analogous to those of  FIG. 5   a - g  showing operation of the second example embodiment shown in  FIG. 7 . 
       
    
    
       [0014]    It will be appreciated that the drawings are illustrative and not limiting of the scope of the invention which is defined by the appended claims. Further, like reference numbers refer to like (but not necessarily identical) elements throughout the figures and the example(s) and variations thereof illustrated in the figures. The embodiments shown accomplish various aspects and objects of the invention. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    With reference more particularly to  FIG. 1 , in the example embodiment shown a table  10  includes adjacent surface portion table end elements  12 ,  14  together defining a top surface  16  of the table of a first, smaller, size area. A storable expansion leaf surface portion element  18  is shown in a first, storage, position underneath the adjacent surface portion table end elements. It fits into a space  20  defined by a decreased thickness portion  22  of each of the two adjacent surface portion table end elements. Table end support arms  24 ,  26 ,  28 ,  30  are attached to the adjacent surface portion table end elements near their outward edges  32 ,  34 , and are positioned below the space  20  occupied by the storable expansion leaf surface portion element. The table end support arms are attached to inner rails  36 ,  38  of a table support structure  40  in a manner described below. The support structure also includes outer rails  42 ,  44 , notched, end rails  46 ,  48  and table legs  50 . The discussion will now be addressed to one side of the table (the near side) where more elements are shown. Many elements on the far side of the table in the drawing have been omitted (hidden behind other structure in the exploded view) for clarity of presentation of the overall configuration, as mentioned above. 
         [0016]    The table end support arms  24 ,  26  are attached to inner and outer sides of the inner rail  36  via liner glides (or slides)  52 ,  54 , respectively. They move through slots  56 ,  58  in the end rail elements  46 ,  48  when the adjacent surface portion table end elements  12 ,  14  are slid apart in expanding the table. The storable expansion leaf surface portion  18  is attached to the near side inner rail  36  of the support structure  40  in the figure via two expansion mechanisms  60 ,  62  as will be further described below, which are in turn attached to the support arms  24 ,  26 , which are themselves in turn slidably attached via the liner glides  52 ,  54  to the inner rail as just described. This can be further appreciated with reference to  FIG. 4  as well as  FIG. 1 . In one embodiments guide blocks  64  carried by the end rails  46 ,  48  can be provided to guide the movement of the storable expansion leaf surface portion and hold it in place centered over the support structure in the illustrated example. In another embodiment a expansion leaf centering arm  66  can be pivotably provided between the storable expansion leaf surface portion  18  and the support structure  40  to restrain sideways movement of said portion  18  while allowing vertical motion thereof. 
         [0017]    With reference to  FIG. 2  and to  FIG. 1 , the expansion mechanism  60 ,  62  is in each case configured to bring the storable expansion leaf surface portion  18  forward to be coplanar with the adjacent surface portion table end elements  12 ,  14  when expanding the top surface of the table  10 ; and to bring it back to a first storage position when collapsing the table example embodiment surface back down to a smaller size. The two mechanisms are disposed in orientation 180 degrees from each other, so as to function essentially identically when the adjacent table end surface elements  12 ,  14  are moving in opposite directions at the same time. Like arrangements are provided at the far side of the table illustrated adjacent expansion table end support arms  28 ,  30 , and again description of the near side does for those like arrangements at the far side as they are essentially identical. 
         [0018]    With particular reference to  FIG. 2 , an expansion mechanism  62  inner housing element  68  is rigidly mated to an outer housing element  70  with a gate/guide bridge element  72  and reversing lever element  74  pivotably disposed therebetween. This rigid mating can be by riveting, welding, fasteners, etc. In the illustrated embodiment the inner housing element is attached to a table end support arm  26 . A reverse lever spring  76 , which acts to bias the reverse lever to each of two positions in reversing movement of the bridge element, as will be described, is disposed between the inner housing element and the support arm ( 26  in  FIG. 1 ) in a cavity ( 78  in  FIG. 1 ) formed in the support arm. A bracket  80  rotatably carrying an idler  82 , for example via a bearing (conventional not shown) is coupled to the storable expansion leaf surface portion ( 18  in  FIG. 1 ), and is positioned adjacent the outer housing element, and can be in contact therewith via glides  84 ,  86  formed of a lubricous material, such as Teflon for example, attached to the bracket and outer housing element, respectively. In one example embodiment the expansion mechanism can be cut off as shown by a line  88  (outline) and this embodiment allows relative travel of any length between the support arm  26  and the rest of the table—allowing the mechanism to be used with multiple sizes of tables. When using a shortened version, more stiffness in the outer housing bracket element  70  may be required as a slot  92  therein then has an open end, making bending under certain conditions an increased possibility to be mitigated. Inclined guiding portions  90  defined by the outer bracket in this example guide the idler  82  into the slot  92  in the outer housing element in operation, as will be described hereafter. 
         [0019]    With reference to  FIGS. 1 ,  3  and  4 , the means for causing the adjacent surface portion table end elements  12 ,  14  to move in opposite directions to each other in a coordinated manner in one example embodiment can be appreciated. A system  94  of pulleys  96 ,  98  and cables  100 ,  102  connect said elements via the end support arms  24 ,  26 . The pulleys are mounted on the stationary inner rail  36  of the support structure  40 . Cable tie elements  104  fix the cables to the support arms so that when one arm moves, the other must move also, the same amount and in the opposite direction, as the cables move around the pulleys requiring this—and essentially no other movement—of one arm  24  with respect to the other  26 . Other means for providing this relative movement can be provided. For example with reference to  FIG. 3   a  a rack and pinion system  106  can be used including gear racks  108 ,  110  coupled to the support arms  24 ,  26  and a pinion gear  112  rotatably coupled to the inner support rail  36 . Note also that instead of the liner glides ( 52 ,  54  in  FIG. 3 ) a conventional tongue and grove slide arrangement  114  can be used in the example table  10  embodiment in providing the described relative movement. 
         [0020]    With reference to  FIG. 2  and to  FIG. 5(   a - g ) operation of the expansion mechanism  62  will now be further described with more particularity. When the table  10  is in the smaller table surface area (collapsed) configuration shown in  FIG. 1  the idler  82  is positioned as shown in  FIG. 5   a . As the table is expanded by pulling out the adjacent surface area table end elements ( 12 ,  14  in  FIG. 1) , the idler moves in the direction of the arrow  111  in the slot  92  defined by the outer bracket  70  toward an inclined portion  116  of the slot. The gate/guide bridge element  72  is disposed in an initial, or bridging position with a narrowed gate/guide portion  118  disposed across the inclined portion of the slot and resting against a stop pin  120  carried by the outer housing element  70 . The reversing lever  74  urges the bridge element to this position via a bridge element engaging pin  121  which extends toward and engages the bridge element. A spring engaging pin  122  extends out on the opposite side through the inner housing bracket member  68  through a slot  123  defining the limits of movement of said pin  122  and the reversing lever through which it passes. The reversing lever in turn is under the biasing influence of the reverse lever spring  76  disposed between an anchor pin  124  and the spring engaging pin  122 . This arrangement provides a two-position over-center functionality for the reverse lever, pivoting back and forth over a pivot pin element  123  which extends from the outer housing bracket element  70  through a pivot hole  125  in the bridge element  72  and like pivot hole  125  in the reversing lever to engage in a hole or recess in the inner housing element  68 . One position of the two positions of the over center arrangement is occupied when the mechanism is in this initial configuration, one where the lever element is “up” in the view(s). 
         [0021]    In the next FIG. ( 5   b ) the mechanism  62  has moved sufficiently with respect to the storable expansion leaf surface bracket  80  that the idler  82  is on the inclined or ramp portion  116  of the slot  92 . At this point the adjacent surface area table end elements ( 12 ,  14  in  FIG. 1 ) are moved aside sufficiently, and as the outer bracket passes by the idler, leaf bracket  80  and the storable expansion surface table leaf element  18  connected thereto urged upward by the ramping action of the idler on the inclined portion of the slot and is rising towards its deployed position coplanar with the adjacent surface area table end elements. The gate/guide/bridge element is tipping—against the bias of the reverse lever spring  76 —upward sufficiently to allow the idler to pass underneath it; however it will not tip sufficiently to trip over-center the position of the lever element  72  by reason of the idler passing underneath the narrowed guide portion  118  of the bridge element. Thus the biasing force on the gate/guide/bridge element remains that which tends to tip the narrowed portion  118  downward as the idler passes out from under it as shown by the arrow  132  into a short level continuation portion  134  of the slot. The end of movement of the idler in this direction  132  stops outward movement of the adjacent surface table end element(s). 
         [0022]    With reference now to  FIG. 5   c  the guide/gate bridge element  72  flips back to its original position after the idler  82  passes under the narrowed gate/guide portion  118 . It thus forms a “bridge” across the inclined (ramp) portion  116  of the slot  92 ; the bridge connecting the short level continuation portion  134  of the slot with a shelf portion  136  which supports the storable expansion surface table leaf element in the deployed position coplanar with the adjacent surface table end elements. Pushing the adjacent surface table end element(s) back towards the now deployed storable expansion surface table leaf element moves the outer housing  70  relative to the idler so that the idler moves across the “bridge” in the direction shown by the arrow  138  until the table surface is contiguous as the elements all are pushed against each other. The shelf portion now can support the leaf element and things placed thereon. 
         [0023]    Turning to  FIG. 5   d  at the same time the adjacent surface table end elements  12 ,  14  are approaching contact with the storable expansion surface table leaf element  18 , the idler is approaching the end of the shelf portion and contacting the reversing lever  74  which covers part of the shelf portion of the slot, pushes the reversing lever downward over-center to its other (down) position shown. This also forces the gate/guide bridge element to tip up to the position shown. This acts to bias the idler to the position at the end of the shelf portion shown in the figure. This is the position at which the table is at the deployed expanded position with the table surface expanded and its elements contiguous. The mechanism thus has a detent functionality holding the table in this configuration during use. The detent must be overcome for the tabletop elements ( 12 ,  14 ,  18 ) to separate preparatory to shrinking of the table top surface area and storage of the leaf portion. Note that the limits of movement of the bridge element  72  are established by an opening  140  through which the pins  120 ,  121  described above pass. Pin  120  prevents further upward tipping of the narrowed gate portion  118 , and pin  122  requires that the reversing lever move against the biasing force of the reversing spring  76  in order to allow the gate portion of the element to move back down, providing the detent function just mentioned. 
         [0024]    With reference to the next figure in the series ( 5   e ) to close the table  10  the ends  12 ,  14  are moved outward by pulling one of them out, overcoming the detent bias and moving the idler  82  back over the “bridge” of the guide/gate bridge element  72  thus tipped down by the idler rolling over it. Note that the bridge element is now biased to tip up, which it will when the idler moves in the direction shown by the arrow  142  onto the short level continuation portion  134  of the slot  92 . This allows the gate/guide bridge element to pivot back up, which it then does—as shown by the next figure ( FIG. 5   f ). This stops outward movement of the table end(s), and the user then pushes the table end being manipulated back toward the extension leaf element  18  in the center of the table  10  to close the table and store said element  18 . The inclined portion  116  of the slot and the narrowed gate/guide portion  118  of the bridge element  72  now urge the idler downward (lowering the leaf) in movement of the idler being downward, but strictly from the reference frame of the mechanism relative movement of the idler is in the direction of the arrow  144  shown. 
         [0025]    With reference to  FIG. 5   g  when the idler moves off the inclined (ramp) portion  116  of the slot  92  and moves along the slot in relevant movement to the housing bracket member  70  in the direction shown by the arrow  146  it contacts the reversing lever  74  (which is still biased to the down position by the reversing spring) which covers part of the slot. The idler moving past the reversing lever moves it upward, over-center, back to the first position, in turn also tipping the gate/guide bridge element to tip back down to its original position (ready for the next cycle) and now biased to that original position by the reversing lever engagement pin  121  as before described. Thus, the whole process is accomplished by moving the table end(s)  12 ,  14  out and back to deploy, and again out and back to store, the storable expansion table leaf element  18 . This is done with relative ease and, to a user, intuitive simplicity, heretofore unknown in the art at the time of filing this disclosure. 
         [0026]    Turning to  FIG. 6 , another example embodiment of the expansion mechanism  150  shown side-by-side with that  62  just described has the relative advantage of the elements being positionable internal to, and in-between the inner bracket housing element  68  and the outer bracket housing element  70 . The mechanism functions essentially the same as before described, but there are a few differences. The reversing lever  74 ′ ( 74  prime) of this other example embodiment is diamond shaped and is over-center biased by a (coincidentally also essentially diamond shaped) over-center cam plate  152  and biasing spring  154 . The spring engages at one end with the cam plate by hooking in a small spring engagement hole  156  adjacent a larger pivot pin hole  158  and at the other end through a spring engagement hole  160  in the reversing lever element  74 ′ into a slot  162  in the other end of the cam plate. The slot allows the spring to compress and expand as the cam plate and reversing lever over-center between two positions (up and down) for the reversing lever as described above. Note that the cam plate also covers part of the slot  92  in the outer housing  70 , and thus can correct a miss-positioning of the rest of the elements of the expansion mechanism with respect to the idler  82  position, should it occur. This will be further appreciated with reference to  FIGS. 7   a - h , analogous to  FIGS. 5   a - g , showing operation of the mechanism. 
         [0027]      FIGS. 7   a - d  are directly analogous to  FIGS. 5   a - d , and the same description of operation applies, with the exception that the function of the reverse lever spring ( 76  in  FIG. 2 ) is taken by the diamond shaped over-center cam plate  152  and biasing spring  154 .  FIG. 7   c  is the same as  FIG. 7   d , except that the intention is now to collapse the table  10 , rather than use it. In other words the end position for deployment is the beginning position for storage. The adjacent surface area table end element  14  is then pulled outward until the idler  82  is at the stop provided by the short level continuation  134  of the slot. This is shown at  FIG. 7   f , which is directly analogous to  FIG. 5   f , with its accompanying description. In  FIG. 7   g , the idler  82  is just beginning to move the reversing lever  74 ′ upward off the lower position and over-center towards the upper position, where it rests as shown in  FIG. 7   h —as the table end element  14  moves inward to its initial closed position shown therein. With reference to  FIG. 7   g  it can be appreciated that (as mentioned above) should the idler accidentally get into the position  160  in the channel  92  and the reversing lever element (and diamond shaped cam plate  152 ) are in the lower position, pulling the table end  14  out will move the cam plate and idler with respect to each other so as to reset the mechanism to the initial configuration shown in  FIG. 7   a , which is also the ending position shown in  FIG. 7   h.    
         [0028]    From the foregoing it will be appreciated that the invention provides the ability to easily and intuitively deploy and store an expansion surface portion from behind at least one adjacent surface portion to expand and contract the area of a surface to be used. Moreover, this functionality can be provided at reasonable cost in a mechanism that can be employed in useful articles as shown by the illustrated example(s) shown and described herein.