Patent Publication Number: US-2005120922-A1

Title: Folding work table

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to a table the legs of which fold, especially a table upon which manual work, such as sawing, is performed.  
      2. Description of the Related Art  
      U.S. Pat. No. 3,646,895, on line 69 of column 1 through line 3 of column 2, describes a Table with Folding Legs as follows:  
      “Table  10  when in use is supported by two sets of legs  17  and  21 . With respect to one set  17  of legs, each leg consists of two pivotally joined portions  16  and  18  which are joined by a pin fastener assembly  22 . When the table is folded, as shown in  FIGS. 1 and 3 , these upper leg portions  18  nest in a position parallel to and alongside the lower leg portions  16 . When this leg set  17  is extended, as shown in  FIGS. 2 and 4 , the respective portions  16  and  18  are pivoted into alignment and prevented from pivoting further than 180° by abutting a stop bracket  24  which is fastened to the upper leg portion  18  by using two screws  26 . In the other leg set  21 , each leg  20  is in one piece.  
      “The respective leg sets  17  and  21  are pivotally joined together on each side of the table by using a pin fastener assembly  28 , which is located so one set of legs  17  will extend lower than the other sets [sic] of legs  21  when the table  10  is folded, and when unfolded and in use, pin fastener assembly  28  holds the legs  16  and  20  together in their strong crossed, diagonal and triangular position.” 
      The device of U.S. Pat. No. 3,646,895, however, has no device to assist in the unfolding of the legs for the table and also has no wheels or handle to facilitate transporting the table when the legs have been folded.  
      The Folding Table of U.S. Pat. No. 5,335,604 is very similar to that of U.S. Pat. No. 3,646,895 except that the free ends of the shorter segment of the jointed legs are connected to one another with a bar.  
      Thus, as with U.S. Pat. No. 3,646,895, the table of U.S. Pat. No. 5,335,604 has no device to assist in the unfolding of the legs for the table and also has no wheels or handle to facilitate transporting the table when the legs have been folded.  
      Although the Worktable of U.S. Pat. No. 5,067,535 has a spring  28  to aid the unfolding of the legs for the table and wheels  30  to make transporting the table when the legs have been folded easier, the spring functions over only a limited range; and the legs to which the wheels are attached extend straight beyond the legs, creating a potential physical conflict with the ground or other objects when the wheels are utilized to push or pull the table.  
      Lines 37 through 39 in column 4 of U.S. Pat. No. 5,067,535 clarify, “Once the legs are moved past the dead center position, springs  28  serve to open the table the rest of the way.” And, on line 66 of column 3 through line 2 of column 4, the patent explains, “Front legs  17  and  19  are each equipped with one caster  30  on their rear sides facing rear legs  18  and  20 . These casters are positioned upwards on legs  17  and  19  such that when the legs are unfolded, they are positioned above the floor on which the table is set.” 
      Moreover, in the folding operation, legs of the table that are in contact with the surface upon which the table rests do not support some of the weight of the table until the table has been partially folded since lines 22 through 28 of column 4 in U.S. Pat. No. 5,067,535 declare, “When the table is in the partially folded-up position shown in  FIG. 5 , the user places the rear legs  18  and  20  on the floor, enabling the weight of the table, particularly when the saw or other tool is attached to tool mounting panel  3 , to overcome the restoring force of springs  28 , causing the table to be folded even further.” 
      Springs are also utilized in the Folding Table for Use with a Table Saw of U.S. Pat. No. 6,182,935. Such springs, though, merely serve, according to lines 3 through 5 in column 6, “ . . . to bias the actuator plate in the locked and lower position . . . ” (Lines 36 through 37 of column 5 explain that the “ . . . actuator plate  60  is . . . used to secure the leg mechanism  25  in the open and closed position . . . . ”) and, as stated in lines 10 through 12 of column 6, “ . . . to bias the legs into an open position when the actuator plate is in the released position . . . . ” 
      Significantly, however, a spring, unlike a piston within a cylinder, does not tend smoothly to resist reverse motion and has more tendency to break loose suddenly.  
      U.S. Pat. No. 6,240,987 applies to a Tool Supporting Device which has a folding main table and two folding auxiliary tables attached to one another as well as wheels for transporting the folded device.  
      The process for folding and unfolding involves significant manipulation, which would render having a tool attached to either the main table or one of the auxiliary tables during the folding process difficult. Furthermore, folding requires that the main table  12  be lifted in order to remove the hooks  42  from the mounting rod  36 ; and, as can be determined from  FIG. 1  and  FIG. 4 , the top of the main table is on the bottom after folding. These facts would provide an additional impediment to having a tool attached to the main table during the folding process. And a final impediment is created by the fact that the auxiliary tables  54  are adjacent to the main table  12  with at least one auxiliary table  54  being upside down after folding.  
      Although the Collapsible Portable Saw Stand of U.S. Pat. No. 6,578,856 can physically support a saw during the folding and unfolding process and possesses wheels to facilitate transportation of the folded stand and saw, it appears that considerable force would have to be used to unfold the stand when the saw is in place.  
      A user would have to hold a bar  26  to maintain two legs  20  on an angle while the user pulls a cord attached to a handle  38  in order to slide one end of a platform  18  holding the saw  12  up the two legs  20 .  
     BRIEF SUMMARY OF THE INVENTION  
      The present Folding Work Table is an improvement for the Table with Folding Legs of U.S. Pat. No. 3,646,895.  
      A first facet of the improvement is a power assist actuator (which comprises a housing having a closed first end, a bore with a piston slidably mounted within the bore, and a second end containing an aperture; pressurized fluid—preferably a gas—on a first side of the piston; and a rod having a first end connected to a second side of the piston, an intermediate portion passing through the aperture in the second end of the housing, and a second end) having a first end (which is also the first end of the housing) pivotally connected to the tabletop and a second end (which is also the second end of the rod) pivotally connected to a first one-piece leg. Preferably, a second power assist actuator also has a first end pivotally connected to the tabletop and a second end pivotally connected to a second one-piece leg. (The orientation of either or both power assist actuators can be reversed, i.e., the first end of a power assist actuator can be pivotally connected to a one-piece leg while the second end is pivotally connected to the tabletop.)  
      In unfolding the table, the vast majority of the weight of the tabletop and any item attached to the tabletop is borne by the one-piece legs while the power assist actuators push the tabletop away from the free end of each one-piece leg, i.e., the end that is not attached to the tabletop. This allows the two two-piece legs (which have two pivotally attached segments) to unfold (a process which involves the rotational movement away from the tabletop of a second end of the segment which has a first end pivotally attached to the tabletop and also includes the second segment rotating from an initial position where such second segment is substantially parallel to the first segment and passes substantially adjacent to the first end of the first segment to a position substantially one hundred and eighty degrees from such first position) and, consequently, enables the free ends of the two-piece legs to be placed on a support surface, such as a floor, thereby rotating the tabletop to a horizontal position.  
      During the folding of the table, the power assist actuators aid in preventing the tabletop and any attached tool from too rapidly rotating toward the free ends of the two-piece legs.  
      A second facet of the improvement involves the attachment of a wheel near the free end of each two-piece leg; bending the free end of each two-piece leg away from the tabletop; and having the angle of the bend, the dimensions of the two-piece legs, and the dimensions and point of attachment for each wheel such that the free ends of the two-piece legs will hold the wheels above the support surface when the two-piece legs have been unfolded to support the tabletop while having such free ends higher than the bottom of the wheels and providing ground clearance for the free end that is substantially equal to the radius of the wheel near that free end when the table has been folded. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       FIG. 1  is a perspective view of the first embodiment of the unfolded Folding Work Table.  
       FIG. 2  is a lateral view of the first embodiment of the unfolded Folding Work Table.  
       FIG. 3  is an end view of the first embodiment of the unfolded Folding Work Table.  
       FIG. 4  illustrates, in a cutaway view, a power assist actuator.  
       FIG. 5  depicts a pin utilized to maintain either or both two-piece legs in an unfolded position.  
       FIG. 6  depicts a pin utilized to maintain either or both two-piece legs in a folded position.  
       FIG. 7  is a perspective view of the second, wheeled, embodiment of the unfolded Folding Work Table.  
       FIG. 8  is a lateral view of the second, wheeled, embodiment of the Folding Work Table in a partially folded state with a tool attached to the tabletop.  
       FIG. 9  is a lateral view of the second, wheeled, embodiment of the Folding Work Table in a completely folded state with a tool attached to the tabletop. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      A first embodiment of the Folding Work Table includes, as illustrated in  FIG. 1 ,  FIG. 2 , and  FIG. 3 , two one-piece legs  1 ,  2 . A first end  3  of the first one-piece leg  1  is pivotally attached to a tabletop  4  having a first end  5 , a second end  6 , a first side  7 , and a second side  8 . Similarly, a first end  9  of the second one-piece leg  2  is pivotally attached to the tabletop  4  but at a point of attachment  10  which is closer to the second side  8  of the tabletop  4  than is the point of attachment  11  for the first end  3  of the first one-piece leg  1 .  
      Two two-piece legs  12 ,  13  also are included. A first end  14  of a first segment  15  of the first two-piece leg  12  is pivotally attached to the tabletop  4 . A second end  16  of the first segment  15  of the first two-piece leg  12  is pivotally attached to a first end  17  of a second segment  18  of the first two-piece leg  12 . Likewise, a first end  19  of a first segment  20  of the second two-piece leg  13  is pivotally connected to the tabletop  4  but at a point of attachment  21  which is closer to the second side  8  of the tabletop  4  than is the point of attachment  22  for the first end  14  of the first segment  15  of the first two-piece leg  12 . A second end  23  of the first segment  20  of the second two-piece leg  13  is pivotally attached to a first end  24  of a second segment  25  of the second two-piece leg  13 .  
      Also, the point of attachment  11  for the first end  3  of the first one-piece leg  1  is closer to the first end  5  of the tabletop  4  than is the point of attachment  22  for the first end  14  of the first segment  15  of the first two-piece leg  12 ; and the point of attachment  10  for the first end  9  of the second one-piece leg  2  is closer to the first end  5  of the tabletop  4  than is the point of attachment  21  for the first end  19  of the first segment  20  of the second two-piece leg  13 .  
      Furthermore, the first one-piece leg  1  is pivotally attached to the second segment  18  of the first two-piece leg  12  at a point  26  intermediate between the first end  17  and the second or free end  27  of the second segment  18 ; and the second one-piece leg  2  is pivotally attached to the second segment  25  of the second two-piece leg  13  at a point  28  intermediate between the first end  24  and the second or free end  29  of the second segment  25 .  
      The point of attachment  11  for the first end  3  of the first one-piece leg  1  is preferably near the first side  7  of the tabletop  4 , and the point of attachment  10  for the first end  9  of the second one-piece leg  2  is preferably near a second side  8  of the tabletop  4 .  
      As indicated above, when either two-piece leg  12 ,  13  is folded, the first segments  15 ,  20  are substantially adjacent to the bottom  30  of the tabletop  4  with such first segments  15 ,  20  substantially parallel to their respective second segments  18 ,  25  and having such second segments  18 ,  25  passing substantially adjacent to the first ends  14 ,  19  of their respective first segments  15 ,  20 . As the two-piece legs  12 ,  13  unfold, the second ends  16 ,  23  of the respective first segments  15 ,  20  rotationally move away from the bottom  30  of the tabletop  4 ; and the second segments  18 ,  25  rotate approximately one hundred eighty degrees in reference to their respective first segments  15 ,  20 .  
      Either the second end  16 ,  23  of the first segment  15 ,  20  or the first end  17 ,  24  of the second segment  18 ,  25  or both may extend beyond the point of pivotal connection  31 ,  32  of the second end  16 ,  23  of the first segment  15 ,  20  and the first end  17 ,  24  of the second segment  18 ,  25 . Preferably, attached either to the top  33 ,  34  of the first segment  15 ,  20  of at least one, and preferably both, of the two-piece legs  12 ,  13  on the portion  35 ,  36 , if any, of such first segment  15 ,  20  that extends away from the first end  14 ,  19  of the first segment  15 ,  20  beyond the point of pivotal connection  31 ,  32  of the second end  16 ,  23  of the first segment  15 ,  20  and the first end  17 ,  24  of the second segment  18 ,  25  or to the top  37 ,  38  of the second segment  18 ,  25  of at least one, and preferably both, of the two-piece legs  12 ,  13  on the portion  301 ,  302 , if any, of such second segment  18 ,  25  that, when the two-piece leg  12 ,  13  has been unfolded, extends away from the second end  27 ,  29  of the second segment  18 ,  25  beyond the point of pivotal connection  31 ,  32  of the second end  16 ,  23  of the first segment  15 ,  20  and the first end  17 ,  24  of the second segment  18 ,  25  is a stop  39 ,  40 . If the stop  39 ,  40  is attached to the top  33 ,  34  of the first segment  15 ,  20 , such stop  39 ,  40  extends over the second segment  18 ,  25  so that such second segment  18 ,  25  cannot rotate more than approximately one hundred eighty degrees from the folded position of such second segment  18 ,  25 . Similarly, if the stop  39 ,  40  is attached to the top  37 ,  38  of the second segment  18 ,  25 , such stop  39 ,  40  extends over the first segment  15 ,  20  so that such second segment  18 ,  25  cannot rotate more than approximately one hundred eighty degrees from the folded position of such second segment  18 ,  25 . (Alternatively, if the stop  39 ,  40  is attached to the second end  16 ,  23  of the first segment  15 ,  20  or the first end  17 ,  24  of the second segment  18 ,  25  on the opposite side of the point of pivotal connection  31 ,  32 , such stop  39 ,  40  must be attached to the bottom  201 ,  202  of the first segment  15 ,  20  of at least one, and preferably both, of the two-piece legs  12 ,  13  or to the bottom  203 ,  204  of the second segment  18 ,  25  of at least one, and preferably both, of the two-piece legs  12 ,  13 , in order to accomplish its function of limiting the rotation of the second segment  18 ,  25  of at least one, and preferably both, of the two-piece legs  12 ,  25  with respect to the first segment  15 ,  20  of such two-piece leg or legs  12 ,  25 .)  
      As discussed above, a first major improvement provided by the present invention to folding tables of this type is the employment of a power assist actuator  41 .  
      And, as seen in  FIG. 4  and explained above, the power assist actuator  41  comprises a housing  42  having a closed first end  43 , a bore  44  with a piston  45  slidably mounted within the bore  44 , and a second end  46  containing an aperture  47 ; pressurized fluid  48 —preferably a gas—on a first side  49  of the piston  45 ; and a rod  51  having a first end  52  connected to a second side  53  of the piston  45 , an intermediate portion  54  passing through the aperture  47  in the second end  46  of the housing  42 , and a second end  55 .  
      The power assist actuator  41  has, as indicated above, a first end  56  (which is also the first end  43  of the housing  42 ) pivotally connected to the tabletop  4  and a second end  57  (which is also the second end  55  of the rod  51 ) pivotally connected to a first one-piece leg  1 . Preferably, a second power assist actuator  58  also has a first end  59  pivotally connected to the tabletop  4  and a second end  60  pivotally connected to a second one-piece leg  2 . (The orientation of either or both power assist actuators  41 ,  58  can, however, be reversed, i.e., the first end  56 ,  59  of a power assist actuator  41 ,  58  can be pivotally connected to a one-piece leg  1 ,  2  while the second end  57 ,  60  is pivotally connected to the tabletop  4 .)  
      Then, as explained above, the power assist actuators  41 ,  58  facilitate the folding and unfolding of the table  100 .  
      Several further subsidiary options also exist.  
      In a first such option, a screw  61  is threadably mounted in the bottom  62  of one of the one-piece legs  1 ,  2  in order to further stabilize the table  100  when it is placed upon a somewhat uneven surface.  
      Also, one or more apertures  63  preferably exist in the first segment  15 ,  20  of one or both two-piece legs  12 ,  13 ; and one or more corresponding apertures  64  exist in the second segments  18 ,  25  of such two-piece leg or legs  12 ,  13  with such aperture  63  and corresponding apertures  64  being so located that, when the two-piece leg  12 ,  13  is unfolded, at least one aperture  63  and one corresponding aperture  64  of such leg  12 ,  13  are so aligned that a pin  65  can, as illustrated in  FIG. 5 , be inserted in such aligned aperture  63  and corresponding aperture  64  to facilitate maintaining the two-piece leg  12 ,  13  in the unfolded position and, when the two-piece leg  12 ,  13  is folded, at least one aperture  63  and one corresponding aperture  64  of such leg  12 ,  13  are so aligned that a pin  65  can, as shown in  FIG. 6 , be inserted in such aligned aperture  63  and corresponding aperture  64  to facilitate maintaining the two-piece leg  12 ,  13  in the folded position.  
      Additionally, either the first one-piece leg  1  or the first two-piece leg  12  can be closer to the first side  7  of the tabletop  4 ; and either the second one-piece leg  2  or the second two-piece leg  13  can be closer to the second side  8  of the tabletop  4 .  
      And, in order further to add stability to the table  100 , a crosspiece  66  is optionally attached between the similar enumerated components in any or all of the following sets: the first segments  15 ,  20  of the two-piece legs  12 ,  13 ; the second segments  18 ,  25  of the two-piece legs  12 ,  13  below the points of pivotal attachment  26 ,  28 ; and the one-piece legs  1 ,  2  below the points of pivotal attachment  26 ,  28 . (Of course, locating a crosspiece  66  in some areas may preclude either the one-piece legs  1 ,  2  or the two-piece legs  12 ,  13  from being completely parallel to one another or from touching the bottom  30  of the tabletop  4  along their entire length when in the folded position; this would, though, simply be one factor for consideration and not necessarily a deterrent to the use of a crosspiece  66 .  
      The second major improvement provided by the present invention to folding tables of this type is, as portrayed in  FIG. 7 ,  FIG. 8 , and  FIG. 9 , the utilization of a first wheel  67  rotably connected to the second segment  18  of the first two-piece leg  12  near the free end  27  of the second segment  18  of the first two-piece leg  12  and a second wheel  68  rotatably connected to the second segment  25  of the first two-piece leg  12  near the free end  29  of the second segment  25  of the second two-piece leg  13 . Near the point of attachment  69  of the first wheel  67  to the second segment  18  of the first two-piece leg  12 , the second segment  18  of the first two-piece leg  12  is bent away from the tabletop  4 , making a first angle α with respect to such second segment  18 . Similarly, near the point of attachment  70  of the second wheel  68  to the second segment  25  of the second two-piece leg  13 , the second segment  25  of the second two-piece leg  13  is bent away from the tabletop  4 , making a second angle β with respect to such second segment  25 . Preferably, the first angle α and the second angle β are substantially equal to one another.  
      The angles α and β of such bends; the dimensions of the first and second two-piece leg  12 ,  13 ; and the points of attachment  69 ,  70  of the first and second wheel  67 ,  68  as well as the dimensions of such wheels  67 ,  68  are, as discussed above, selected such that the free-ends  27 ,  29  of the second segments  18 ,  25  of the two-piece legs  12 ,  13  will, as depicted in  FIG. 7 , hold the wheels  67 ,  68  above a surface supporting the table  100  when the two-piece legs  12 ,  13  have been unfolded to support the tabletop  4  while, as shown in  FIG. 9 , having such free ends  27 ,  29  higher than the bottoms  71 ,  72  of the wheels  67 ,  68  and providing ground clearance for each free end  27 ,  29  that is preferably substantially equal to the radius  73 ,  74  of the wheel  67 ,  68  near such free end  27 ,  29  when the table  100  has been folded. (For purposes of illustration, a tool  75  is shown attached to the tabletop  4  in  FIG. 8  and  FIG. 9 .)  
      When there are no wheels  67 ,  68 , the free ends  27 ,  29  of the second segments  18 ,  25  of the two-piece legs  12 ,  13  as well as the free or second ends  76 ,  77  of the first and second one-piece legs  1 ,  2  are preferably bent outward in order to add additional stability to the table  100 . When there are wheels  67 ,  68 , the free ends  76 ,  77  of the first and second one-piece legs  1 ,  2  are bent outward sufficiently to avoid the wheels  67 ,  68 .  
      Furthermore, when a one-piece leg  1 ,  2  is inside the two-piece legs  12 ,  13 , either there can be no axle  78  extending between the wheels  67 ,  68  or such one-piece leg must be shaped to avoid an axle  78  extending between the wheels  67 ,  68  when the table  100  has been folded.  
      Especially when wheels  67 ,  68  are employed, it is preferable to have a handle  79  attached to the tabletop  4  near a first end  5  of such tabletop  4 . And, using any technique that is well known in the art, the handle  79  can preferably be extended from such first end  5  and locked into place. One example of such a well-known technique is having a tube  80  attached to the bottom  30  of the tabletop  4  with the handle  79  slidably mounted with the tube  80  in such a manner that a first end  81  of the handle  79  extends from a first end  82  of the tube  80  past the first end  5  of the tabletop  4  while a second end  83  of the handle  79  extends from a second end  84  of the tube  80  in substantially the opposite direction, viz., under the tabletop  4 ; a stop  85  attached to the second end  83  of the handle  79  precludes the second end  83  of the handle  79  from entering the tube  80  so that the handle  79  cannot slide from the tube  80 ; and a thumb screw  86  is mounted within a threaded aperture  87  of the tube  80  for locking the handle  79 , in position when such handle projects a desired distance from the tube  80 .  
      As used herein, the terms “substantially” and “approximately” indicate that one skilled in the art would consider the value modified by such terms to be within acceptable limits for the stated value. Also as used herein the term “preferable” or “preferably” means that a specified element or technique is more acceptable than another but not that such specified element or technique is a necessity.