Abstract:
Mobile folding restaurant booth style benches are provided, which may be arranged in opposed pairs to form restaurant style booths. An individual bench incorporates a mechanism for shifting the weight of the bench between a mobile base, which may be supported by swivel casters, and a stationary base, which may be supported by non-slip feet, actuated by pivoting a bench seat down from a folded storage position to an unfolded seating position. The weight shifting mechanism may include an engagement member, which is initially spaced apart from an actuator at a folded angle of the seat, and which contacts and begins transmitting force and movement to the actuator at a partially unfolded angle of the seat. Preferably, the bench further includes a biasing component that biases the stationary base upward relative to the mobile base, a locking mechanism that resists a force provided by the biasing component to retain the bench seat in the unfolded seating position, contoured shells or other covers for the seat and a seat back, and a back panel extending vertically above the seat back.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation in part of U.S. patent application Ser. No. 15/048,596, filed Feb. 19, 2016, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to mobile bench seating and, more particularly, to mobile bench seating styled such that opposed pairs of bench seating units arranged with a table between them resemble a typical restaurant booth. 
       BACKGROUND 
       [0003]    Many people enjoy booth style seating. Compared to a table with individual movable or attached stools or chairs, booth style seating can provide comfort and create intimacy in a public setting, with its typical wide, contoured or cushioned seats, high seat backs, and frequently a privacy panel extending above the top of the seat backs. Thus, booth seating is commonly included in the customer dining/lounge areas of restaurants, bars, coffee shops, and the like. However, booth style seating has been traditionally less common in school cafeterias and other institutional settings, where demands of mobility, efficient storage, and ease of cleaning often outweigh concerns regarding comfort and intimacy. Due to high seat backs, privacy panels, and the prevalence of unused bench surface between occupants which would otherwise be empty space between individual chairs or stools, booth seating is typically more bulky and heavier than individual seating, making it more difficult to move and store. Moreover, in addition to immobility, the typical positioning of booth seating next to a wall compounds the difficulty of cleaning on, around, and under booths. 
         [0004]    A need therefore exists for a booth style bench that can provide comfort and privacy without sacrificing mobility, space-efficient storage, and ease of cleaning. 
       SUMMARY OF THE INVENTION 
       [0005]    According to an aspect of the invention, a mobile folding bench is provided, which converts between a mobile folded storage position and a stationary unfolded seating position simply by pivoting a seat between the two positions. The bench comprises a generally vertically oriented seat back comprising a forward facing seat back surface configured to support the back of a sitting human occupant; a seat comprising a sitting surface configured to seat the human occupant, the seat disposed in front of the seat back; a mobile base comprising at least one mobile floor surface contacting support member; a stationary base comprising at least one stationary floor surface contacting support member; the seat back being supported by at least one of the mobile base and the stationary base; a base biasing member connected between the mobile base and the stationary base and biasing the stationary base in a generally upward direction relative to the mobile base; and a base lifting member operatively connected to the seat and configured to transmit a lifting force to the stationary base to lift the mobile base relative to the stationary base when the seat is moved from the folded position to the seating position, so that the folding bench is supported on the floor surface by the stationary support member. The mobile floor surface contacting support member may be any support member configured to facilitate lateral movement across a floor surface, such as a glide or swivel caster. The stationary base is movably coupled to the mobile base to permit at least vertical movement of the stationary base relative to the mobile base, and the stationary support member preferably inhibits lateral movement of the stationary base relative to the floor surface. The seat is supported by and pivotally coupled to the stationary base to move between a seating position in which the sitting surface is at a generally horizontal sitting angle and a folded position in which the sitting surface is at a generally vertical folded angle. The biasing member preferably provides a sufficient base biasing force to maintain the stationary support member at a vertical clearance distance above the floor surface when the mobile support member contacts the floor surface and the seat is in the folded position, so that the folding bench is supported on the floor surface by the mobile support member. 
         [0006]    In one embodiment, the folded angle of the sitting surface is inclined at least about 45° relative to the floor surface. 
         [0007]    In another embodiment, the seat back is supported by the stationary base. 
         [0008]    In yet another embodiment, the engagement member is integral to the seat. 
         [0009]    In still another embodiment, the bench further comprises an actuation member operatively connected to the mobile base, the engagement member configured to contact the actuation member and to transmit a lifting force from the stationary base to the mobile base through the actuation member during movement of the seat from the folded position to the seating position. The engagement member may be configured to contact the actuation member at an engagement position of the seat between the folded position and the seating position, to be spaced apart from the actuation member when the seat is between the folded position and the engagement position, and to remain in contact with the actuation member when the seat is between the engagement position and the seating position. A hook-shaped contact portion of the engagement member may have a curved profile configured to maintain generally vertical normal contact with a lower portion of the actuation member during pivotal movement of the engagement member and vertical movement of the actuation member. The actuation member may comprise a generally horizontal bar housed in a bushing, the bushing configured to be contacted by the engagement member and to rotate around the bar during movement of the engagement member in contact with the bushing to inhibit rubbing between the engagement member and the actuation member. The actuation member may be pivotally connected or integrally attached to the mobile base, or otherwise configured to move vertically in concert with the mobile base. 
         [0010]    In yet another embodiment, a generally downward facing surface of the seat is configured to abut a generally upward facing surface of the stationary base when the seat is in the seating position, to prevent over-travel of the seat past the seating position. The seat may additionally be supported on the floor surface by a leg that pivots from a stowed position adjacent to or stowed within the seat, when the seat is folded to the mobile storage position, to a generally perpendicular orientation relative to the seat extending downwardly to the floor surface when the seat is unfolded to the seating position. Alternatively, the upward facing surface of the stationary base may be an upward facing surface of a fixed leg beam joined to a top end of a fixed leg, and the fixed leg may be an elongate leg extending generally vertically from the fixed leg beam down to a non-slip foot at the bottom of the fixed leg which contacts the floor surface when the seat is in the seating position. The non-slip foot at the bottom of the fixed leg may be located generally below the upward facing surface of the fixed leg beam. For example, the foot may be located directly below the upward facing surface, or it may slightly offset therefrom, such as in a forward direction, to provide enhanced tipping prevention. 
         [0011]    In still another embodiment, the stationary base is connected to the mobile base by a sliding connection constraining the stationary base to generally vertical upward and downward movement relative to the mobile base. This sliding connection may comprise a smaller perimeter tube integral to one of the stationary base and the mobile base slidingly housed in a larger perimeter tube integral to the other of the stationary base and the mobile base. In this and other embodiments, the bench may further comprise a stop mechanism to limit vertical travel of the stationary base relative to the mobile base to movement between an uppermost position of the stationary base and a lowermost position of the stationary base. In particular, a generally horizontal pin may be carried by one of the smaller perimeter tube and the larger perimeter tube, the other of the smaller perimeter tube and the larger perimeter tube comprising a generally vertical slot slidably receiving the pin, the slot comprising an upper end and a lower end, the pin abutting against one of said ends of the slot at an uppermost position of the stationary base relative to the mobile base, and the pin abutting against the other of said ends of the slot at a lowermost position of the stationary base relative to the mobile base, to prevent upward movement of the stationary base from said uppermost position or downward movement of the stationary base from said lowermost position. 
         [0012]    In yet another embodiment, the bench further comprises a retention mechanism configured to be engaged when the seat is in the seating position and to resist movement of the seat away from the seating position or upward movement of the stationary base relative to the mobile base. The retention mechanism may, for example, comprise a locking pin engaging a locking hole in one or both of the stationary base and the mobile base when the seat is in the seating position and the stationary support member is contacting the floor surface, so that movement of the seat toward the folded position or downward movement of the mobile base relative to the stationary base requires a human user manually withdrawing the locking pin from the locking hole. Alternatively, the retention mechanism comprises a detent mechanism in which a rounded surface of a detent member carried by one of the stationary base and the mobile base is received by and generally horizontally biased into a detent recess carried by the other of the stationary base and the mobile base, so that movement of the seat toward the folded position or downward movement of the mobile base relative to the stationary base requires applying a force sufficient to dislodge the detent member from the detent recess, the base biasing force of the base biasing member being insufficient to dislodge the detent member from the detent recess. The latter detent mechanism has the advantage over the locking pin mechanism of facilitating passive engagement and disengagement triggered by the single motion of pivoting the seat. 
         [0013]    According to another aspect of the invention, a method of arranging restaurant booth style seating using two mobile folding benches and a table is provided. Each mobile folding bench may comprise any of the above-described combinations of elements according to the mobile folding bench aspect of the invention. The method comprises moving a first one of the benches having a first seat in the folded position and a first mobile base engaging a floor surface, to a position in which a first seat back surface of the first bench faces a first side of the table; unfolding the first seat to the seating position to cause a first mobile base of the first bench to disengage from the floor surface and a first stationary base of the first bench to engage the floor surface; moving a second one of the benches having a second seat in the folded position, having a second mobile base engaging a floor surface, to a position in which a second seat back surface of the second bench faces a second side of the table; and unfolding the second seat to the seating position to cause a second mobile base of the second bench to disengage from the floor surface and a second stationary base of the second bench to engage the floor surface. 
         [0014]    In one embodiment in which one or both of the mobile folding benches comprises a manually engaged retention mechanism such as a retractable locking pin mechanism, the method further comprises engaging the retention mechanism when the respective seat is in the seating position, the retention mechanism resisting the respective base biasing force of the respective base biasing member to retain the respective seat in the seating position and the respective stationary frame in engagement with the floor surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a front perspective view of a mobile folding bench according to an aspect of the invention, in a mobile, folded storage position, with seat back and seat shells removed to reveal its mechanisms. 
           [0016]      FIG. 1A  is a bottom plan view of a spring loaded ball component for use in a retention mechanism in a bench as in  FIG. 1 . 
           [0017]      FIG. 1B  is a perspective view of a ball recess component for use in conjunction with the spring loaded ball component shown in  FIG. 1A . 
           [0018]      FIG. 2  is a side elevation view of the bench shown in  FIG. 1  in an unfolded, stationary seating position, with the positions of seat back and seat shells depicted in phantom view. 
           [0019]      FIG. 3  is a side elevation view of the bench as shown in  FIG. 2 , in a partially folded position in which its mobile and stationary bases contact a supporting floor surface simultaneously. 
           [0020]      FIG. 4  is a side elevation view of the bench as shown in  FIG. 2 , in a partially folded position of initial engagement of an engagement member for shifting the bench from a mobile frame to a stationary frame. 
           [0021]      FIG. 5  is a side elevation view of the bench as shown in  FIG. 2 , in the mobile, folded storage position shown in  FIG. 1 . 
           [0022]      FIG. 6  is a side elevation view of an alternative embodiment of a mobile folding bench according to an aspect of the invention, in a stationary, unfolded seating position. 
           [0023]      FIG. 7  is a fragmentary perspective view of the left side of the bench shown in  FIG. 1 , in a partially folded position. 
           [0024]      FIG. 8  is a fragmentary perspective view of the bench as shown in  FIG. 7 , in a stationary, unfolded seating position. 
           [0025]      FIG. 9  is a perspective view of a seat back shell for use in a mobile folding bench according to an aspect of the invention. 
           [0026]      FIG. 10  is a perspective view of a seat shell for use in a mobile folding bench according to an aspect of the invention. 
           [0027]      FIG. 11  is a side elevation view of four mobile folding benches arranged around two tables to form a pair of adjacent restaurant style booths according to another aspect of the invention. 
           [0028]      FIG. 12  is a perspective view of a fixed-leg mobile bench according to another aspect of the invention, in a seating position. 
           [0029]      FIG. 13  is a right side elevation view of the mobile bench of  FIG. 12 , in a mobile storage position. 
           [0030]      FIG. 14  is a right side elevation view of the mobile bench of  FIG. 12 , in the seating position. 
           [0031]      FIG. 15  is a top plan view of the mobile bench of  FIG. 12 , in the seating position. 
           [0032]      FIG. 16  is a front elevation view of the mobile bench of  FIG. 12 , in the seating position. 
           [0033]      FIG. 17  is a perspective view of mobile and stationary frames of the mobile bench depicted in  FIGS. 12-16 . 
           [0034]      FIG. 17A  is a partial cutaway perspective view of slidingly mated uprights of a mobile and stationary frames shown in  FIG. 17 , respectively, housing a piston-cylinder assembly. 
           [0035]      FIG. 17B  is a partial cutaway perspective view of the mobile bench of  FIG. 12  in a mobile storage position, including a stop mechanism thereof. 
           [0036]      FIG. 18  is an exploded perspective view of a seat of the mobile bench depicted in  FIGS. 12-16 . 
           [0037]      FIG. 19  is an exploded perspective view of a seat back of the mobile bench depicted in  FIGS. 12-16   
           [0038]      FIG. 20  is a perspective view of a mobile booth comprising two mobile benches as depicted in  FIGS. 12-16  on opposite sides of a mobile table. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    With reference to the accompanying drawing figures, a mobile folding restaurant booth style bench according to the invention will now be described in detail. A mobile folding bench  10  according to the invention includes a mobile base embodied as a pair of caster frames  12   a ,  12   b  that engage a supporting floor surface FS when bench  10  is in a mobile, folded storage position, depicted in  FIG. 1 , to facilitate easy movement of bench  10  between a storage location and a use location. In addition, bench  10  includes a stationary base embodied as a footed stationary frame  14  that engages floor surface FS in an unfolded, seating position of bench  10  illustrated from the right side in  FIG. 2 . Notably, when in the seating position, bench  10  is solely supported by non-slip feet, including four non-slip feet  16  at four outwardly positioned corners of stationary frame  14  which bear most of the weight of bench  10 , and two non-slip feet  68  of a pivoting seat front leg member  62  (discussed in more detail below), which serve primarily to bear a portion of the weight of any bench occupants and to prevent an occupied bench  10  from tipping forward, as best understood with reference to  FIG. 2 . Thus, during normal use, bench  10  is fully immobilized and stabilized against tipping. The use of the terms “stationary frame” and “caster frames” is merely intended to be descriptive of the skeletal aspect of the respective bases of the illustrated embodiments, which may be formed from steel tubing, for example, and not to limit the invention to exclude stationary or mobile bases having a bulk solid or shell geometry. 
         [0040]    Illustrative linkage components and a sequence of folding bench  10  from the seating position to the folded position are shown in  FIGS. 2-5 . With reference to  FIG. 2 , a seat  18  of bench  10  is pivotally mounted to stationary frame  14 , and a seat back  20  of bench  10  is fixedly mounted to stationary frame  14 . The collective weight of seat  18  and seat back  20  is supported by stationary frame  14 . 
         [0041]    Mounting seat back  20  to stationary frame  14  has the benefit of maintaining a fixed relative height relationship between seat back  20  and seat  18 , which is also connected to stationary frame  14 . In addition, mounting seat back  20  to stationary frame  14  instead of to caster frames  12   a ,  12   b  allows caster frames  12   a ,  12   b  to be unattached to and independent of each other, allowing for independent suspension and thus smoother travel when moving bench  10  on casters  24 . This arrangement also inhibits the possibility of sliding mechanisms locking up due to tilting of a unitary caster frame in response to unevenly applied forces when folding and unfolding bench  10 . 
         [0042]    Notwithstanding certain disadvantages mentioned above, seat back  20  could alternatively be attached to caster frames  12   a ,  12   b . Although this would increase the amount of weight supported by caster frames  12   a ,  12   b  suspended above floor surface FS when bench  10  is in the seating position, it would in the same measure decrease the amount of force required from a suitable biasing component (described in more detail below as cylinder assembly  26 ) to support stationary frame  14  above floor surface FS. Thus, attaching seat back  20  to caster frames  12   a ,  12   b  instead of stationary frame  14  would have minimal if any net effect on the amount of effort required to deploy bench  10  in the seating position, which requires lifting the weight of caster frames  12   a ,  12   b  and opposing the biasing force tending to lift stationary frame  14 . An engagement member  22  fixedly attached to seat  18  supports caster frames  12   a ,  12   b  suspended above floor surface FS, applying a lifting force to each of a pair of actuators  23  that are operatively connected to each caster frame  12   a ,  12   b  to maintain a clearance C C  between casters  24  of caster frames  12   a ,  12   b  and floor surface FS. 
         [0043]    A suitable biasing component is operatively connected between stationary frame  14  and caster frames  12   a ,  12   b  so as to bias stationary frame  14  in an upward direction relative to caster frames  12   a ,  12   b . For example, the biasing component may be a compressed gas cylinder assembly  26 , including a piston  27  connected to each caster frame  12   a ,  12   b  and a cylinder  29  connected to stationary frame  14 , cylinder assembly  26  providing a biasing force tending to extend its length by forcing an increasing length of piston  27  out of cylinder  29 . Other suitable biasing components (not shown) may include, without limitation, solid state compression, tension, or torsion springs (such as a torsion bar), or magnets. 
         [0044]    Thus, to lift caster frames  12   a ,  12   b  from floor surface FS and lower stationary frame  14  into engagement with floor surface FS, engagement member  22  must bear the sum of the weight of caster frames  12   a ,  12   b  and the biasing force from cylinder assembly  26 , in turn transmitting these forces through seat  18  to stationary frame  14 . To retain bench  10  in this position, a sufficient moment must be applied to seat  18 , supplied either by the weight of an occupant sitting on seat  18  or by a suitable resistance or locking mechanism (discussed in more detail below), to counterbalance the resultant moment about a seat pivot joint  28  produced by the downward force of actuators  23  on engagement member  22 . 
         [0045]    Turning to  FIG. 3 , a partially folded intermediate position of bench  10  is depicted, in which seat  18  has been pivoted up, and thus engagement member  22  has been pivoted down, to permit the lowering of actuators  23  and caster frames  12   a ,  12   b  to a position in which the bottoms of casters  24  and feet  16  are aligned on the same horizontal plane, so that they contact floor surface FS simultaneously. Raising seat  18  further from this position shifts the weight of bench  10  fully onto casters  24 , while lowering seat  18  further from this position shifts the weight of bench  10  back to feet  16 . 
         [0046]    Next, as seat  18  continues to be raised, a loss of engagement position (or initial engagement position for the reverse, lowering sequence of seat  18 ) of engagement member  22  and actuators  23  is reached, as shown in  FIG. 4 . In this position, engagement member  22  and actuators  23  are touching, but no force is transmitted between them. This initial engagement/loss of engagement position corresponds to the maximum extension of cylinder assembly  26  and thus the highest position to which it can lift stationary frame  14  above caster frames  12   a ,  12   b . This highest position may, for example, be the position at which a variable biasing force equals the combined weight of stationary frame  14  and its attached components. In that case, the biasing force would be initially larger than the combined weight of frame  14  when seat  18  is fully unfolded, and would be reduced to a force equal to said combined weight as cylinder assembly  26  extended. 
         [0047]    More preferably, the highest position of the stationary frame is a fixed position in which a member or component of bench  10  meets an obstruction, which may correspond to piston  27  reaching the end of its travel or some other stop member abutting against a stop surface. This allows the biasing force to be substantially greater than the weight it supports throughout the relative movement of caster frames  12   a ,  12   b  and stationary frame  14 , providing fast lift assist action, without overshooting the desired highest position of stationary frame  14 . In the illustrated example, a stop pin  30  travels up and down with each caster frame  12   a ,  12   b , within a slot  32  formed in stationary frame  14 . When stop pin  30  reaches a bottom end  33  of slot  32 , as seen in  FIG. 1 , stationary frame  14  can be raised no higher and cylinder assembly  26  can extend no farther. The highest position of stationary frame  14  should be established so that engagement member  22  and actuators  23  are relatively positioned for effective force transmission at the initial engagement position, as also mentioned below. 
         [0048]    Continuing to pivot seat  18  upward from the loss of engagement/initial engagement position shown in  FIG. 4  to an approximately vertical orientation produces the folded position of bench  10  shown in  FIG. 5 , in which a clearance C F  is maintained between feet  16  and floor surface FS. As noted above, in this position stationary frame  14  floats above caster frames  12   a ,  12   b  on cylinder assembly  26 . An ancillary benefit provided by this arrangement is shock absorption; that is, if casters  24  roll over a bump (such as a doorway threshold) while a human user is transporting bench  10  in the folded position, the shock of the bump will be absorbed by a slight compression of cylinder assembly  26 , reducing any jolt felt by the user. 
         [0049]    Additional components and features supporting the folding of bench  10  between its seating and folded positions will now be described with reference to  FIGS. 1, 7, and 8 . 
         [0050]    As best shown in  FIG. 1 , each actuator  23  comprises an actuator column  34  connected at its lower end to the respective caster frame  12   a ,  12   b , a lift bar  36  integral to and extending horizontally from actuator column  34 , and a low friction contact bushing  38  rotatably mounted on lift bar  36 . Thus, as engagement member  22  pivots between the loss of engagement/initial engagement position and the seating position, and the point of contact between engagement member  22  and bushing  38  shifts with respect to engagement member  22 , bushing  38  slidingly rotates around lift bar  36 . Bushing  38  thus prevents rubbing and wear between engagement member  22  and lift bar  36 . Also, it will be noted that engagement member  22  comprises a curved contact region  40  providing contact with bushing  38  throughout the engaged range of motion. The upward concavity of contact region  40  helps to maintain approximately vertical transmission of force to actuators  23  throughout the pivoting of engagement member  22 . 
         [0051]    In alternative embodiments in which a contact region of an engagement member instead includes a contact region with a straight profile (not shown), the direction of a normal (perpendicular) contact force transmitted from the engagement member would inevitably deviate from vertical to some degree. The size of the angle by which the force transmission direction would deviate from vertical for a straight-profile contact region may be limited by appropriately establishing its initial angle (for example by adjusting parameters including the size, shape, and attachment location of the engagement member and/or setting the maximum height to which stationary frame  14  is raised in one of the ways described above) and limiting the angular range of motion of the engagement member through which it remains in contact with actuators  23 . 
         [0052]    In other embodiments, different force transmission components, such as pneumatics, hydraulics, magnets, or rack-and-pinion gear assemblies, for example, may be employed in lieu of a sliding normal contact engagement member to convert pivotal movement of seat  18  into relative vertical movement of caster frames  12   a ,  12   b  and stationary frame  14 , which may inherently avoid the problem of a varying direction of force transmission. In such embodiments, the alternative force transmission components may also be configured so that seat  18  can transmit force and movement to the frames not only when pivoting down (forcing stationary frame  14  down and caster frames  12   a ,  12   b  up), but also when pivoting up (forcing caster frames  12   a ,  12   b  down and stationary frame  14  up). A mechanism in which upward pivoting of the seat is converted to upward vertical movement of the stationary frame could substitute for a base biasing component, as the force required to raise the stationary frame could instead be provided by a user in folding the seat, and the bench could be retained in the folded position by a suitable locking mechanism, which may be similar to locking mechanisms discussed below for retaining the bench in the unfolded seating position. Alternatively, a biasing component may nonetheless be used to assist a user in raising the stationary frame, but need not provide a force equal to the entire weight of the stationary frame and its attached components if a lifting force is transmitted to the stationary frame by folding the seat. 
         [0053]    Optionally, as in the illustrated embodiment, each actuator column  34  may be connected to the respective caster frame  12   a ,  12   b  by a pivotal joint  44 , and slidingly retained in a sliding collar  46  fixed with respect to stationary frame  14 , collar  46  allowing column  34  some clearance to pivot but retaining column  34  in an approximately upright orientation. This connection arrangement of actuator column  34  permits column  34  to seek an angle in which the force transmission direction from engagement member  22  to actuators  23  is generally aligned with column  34 , to inhibit possible fatigue of column  34  due to repetitive bending stresses. 
         [0054]    In the illustrated embodiment, stationary frame  14  is constrained solely to vertical sliding movement relative to caster frames  12   a ,  12   b . This vertical sliding connection between caster frames  12   a ,  12   b  and stationary frame  14  is provided by smaller perimeter uprights  48  of caster frames  12   a ,  12   b  slidingly inserted into larger perimeter uprights  50  of stationary frame  14 , uprights  48  carrying one or more of the aforementioned stop pin  30  and uprights  50  having a corresponding one or more of the aforementioned slot  32  formed therein. As shown in the drawings, particularly  FIG. 1 , each of four uprights  48  carries a stop pin  30 , and each of four uprights  50  includes a corresponding slot  32 . 
         [0055]    As mentioned above, when bench  10  is in the seating position, a suitable locking mechanism may be employed to oppose or resist the tendency of cylinder assembly  26  to extend, thereby forcing seat  18  to pivot upward and lifting stationary frame  14  off of floor surface FS. A passive locking mechanism is preferred, being capable of providing sufficient resistance to maintain bench  10  in the seating position, but also capable of being disengaged by a sufficient lifting force applied to seat  18  without harming any components or requiring a separate action by a human operator, such as pulling out a pin or sliding a bolt before lifting. In addition, the passive locking mechanism preferably engages automatically when seat  18  is lowered to the seating position, without requiring an additional action such as inserting a pin or sliding a bolt. One such passive locking mechanism is a spring loaded ball detent locking mechanism  47   a ,  47   b , best shown in  FIGS. 1, 7, and 8 . Detent locking mechanism  47   a ,  47   b  includes a spring loaded ball component  53   a ,  53   b  attached to a plate  51   a ,  51   b  carried by seat  18 , which snaps into a recess  55   a ,  55   b  formed in a plate  57   a ,  57   b  carried by stationary frame  14  when bench  10  is in the seating position, requiring a threshold lifting torque on seat  18  greater than that provided by cylinder assembly  26  to dislodge or pop ball component  53   a ,  53   b  out of engagement with recess  55   a ,  55   b . Plate  51   a  having attached ball component  53   a  is shown in greater detail in  FIG. 1A , and plate  57   a  having recess  55   a  formed therein is shown in greater detail in  FIG. 1B . 
         [0056]    Certain features and components of bench  10  serve to prevent over-travel of seat  18  in the downward pivoting direction past its generally horizontal orientation in the seating position. Thus, it will be noted that slot  32  has an upper end  52  in addition to bottom end  33  already mentioned. Upper end  52  limits the upward travel of the respective caster frame  12   a ,  12   b , thus preventing downward pivoting over-travel of seat  18  from pivoting downward past its generally horizontal orientation in the seating position. Additionally, a generally flat top surface  54  of an upright  56  of stationary frame  14 , to which seat  18  is pivotally connected, abuts a flat bottom surface of panel  58  when seat  18  is in the seating position, also preventing downward pivoting over-travel of seat  18 . Finally, detent locking mechanism  47   a ,  47   b  may provide yet another redundant safeguard against downward over-travel of seat  18 , should the others fail. 
         [0057]    Notwithstanding the foregoing stop mechanisms, it may be desirable to provide front legs to support seat  18 , to enhance stability against forward tipping of bench  10  while also preventing undue bending stresses on a seat base panel  58  and/or shear stresses on hinge mounting plates  60  or other connections between seat base panel  58  and stationary frame  14  by bracing the front end of seat base panel  58  against floor surface FS. Thus, a pivoting seat front leg member  62  comprising a pair of seat front legs  64  is provided in the illustrated embodiment. A pair of guide links  66  are pivotally connected between each front leg  64  and the corresponding adjacent upright  56  of stationary frame  14 , to facilitate compact retention of leg member  62  in the folded position of bench  10  and to align each front leg  64  vertically in the seating position. Similarly to stationary frame  14 , front leg member  62  is provided with non-slip feet  68  to further inhibit sliding on floor surface FS. 
         [0058]    In addition to the components described in the above paragraphs, bench  10  may incorporate any suitable combination of panels, contoured shells, cushions or other appropriate seat cover structure to promote ergonomics, comfort, and/or aesthetic appeal. For example, as illustrated in  FIGS. 2-5 , seat back  20  may include a seat back shell  70 , as depicted in  FIG. 9 , and seat  18  may include a seat shell  72 , as depicted in  FIG. 10 . Seat back shell  70  and seat shell  72  may be formed from any suitable material, such as plastic, wood, or fiberglass. Seat shell  72  may be attached to seat base panel  58  in any suitable manner or may be integral thereto. Similarly, seat back shell  70  may be fixedly attached by any suitable connecting structure (not shown) to a seat back base panel  74  or may be integral thereto. In turn, seat back base panel  74  is attached to rear uprights  73  of stationary frame  14  by a suitable joint  75 . In the embodiment depicted as bench  10  having seat back shell  70  and seat shell  72 , joint  75  is preferably a fixed joint. For aesthetic and safety purposes, it may be desirable to substantially conceal and/or cover at least a substantial portion of engagement member  22  and/or actuators  23  inside seat back shell  70  and/or seat shell  72 . Thus, notches  76  (shown in  FIG. 9 ) are preferably provided in a bottom front edge of seat back shell  70 , and notches  78  (shown in  FIG. 10 ) in a bottom rear edge of seat shell  72 , to permit protrusion of some portion of engagement member  22  into the interior of seat back shell  70  when bench  10  is in the seating position, as illustrated in  FIG. 2 . 
         [0059]    In another embodiment depicted in  FIG. 6 , a bench  10 ′ includes an alternative seat back  20 ′ accommodated with a generally flat, contoured seat back panel  80  attached in a suitable manner to seat back base panel  74 , and an alternative seat  18 ′, which may comprise a contoured seat panel  82 . In bench  10 ′, seat back base panel  74  is attached to rear upright  73  by a joint  75 ′ which may be a fixed or adjustable pivot joint, in the latter case preferably providing friction or locking means to retain base panel  74  at a selected angle. Seat panel  82  may attach directly to front leg member  62  and stationary frame uprights  56  as shown in the drawing, or it may attach in a suitable manner to a seat base panel similar to seat base panel  58 . 
         [0060]    Finally, a privacy panel  84  is preferably provided to separate the seating space provided by one booth from that of adjacent booths and/or from common spaces or walking areas. In addition, a portion of privacy panel  84  extending above seat back shell  70  can be advantageously used to display printed designs, such as a school emblem or a restaurant logo. Thus, illustrated in  FIG. 11  is an example arrangement of two booths  86  arranged back-to-back adjacent a wall W, each booth  86  defined by a pair of benches  10  as previously described, facing opposite sides of a table  88 . 
         [0061]    Turning to  FIGS. 12-20 , in accordance with another embodiment, a fixed-leg bench  10 ″ will now be described. Fixed-leg bench  10 ″ includes a mobile base embodied as caster frames  90   a ,  90   b  that engages a supporting floor surface FS when bench  10 ″ is in a mobile, folded storage position, depicted in  FIG. 13 , to facilitate easy movement of bench  10 ″ between a storage location and a use location. In addition, bench  10 ″ includes a stationary base embodied as a footed stationary frame  92  that engages floor surface FS in an unfolded, seating position of bench  10 ″ illustrated from the right side in  FIG. 14 . 
         [0062]    When in the seating position, bench  10 ″ is solely supported, at four outwardly positioned corners of stationary frame  92 , by rear non-slip feet  94   a  and front non-slip feet  94   b . Bench  10 ″ differs from benches  10  and  10 ′ described above primarily in this regard; that is, instead of a pivoting seat front leg member  62 , bench  10 ″ employs the front two corner uprights of stationary frame  92  as fixed legs  95  having non-slip feet  94   b  at their lower ends. Preferably, fixed legs  95  are positioned sufficiently forwardly with respect to a seat  96  to prevent forward tipping during normal seating use of bench  10 ″, but without excessively expanding the depth dimension of bench  10 ″ in the folded mobile storage position. 
         [0063]    Seat  96  of bench  10 ″ is pivotally mounted to stationary frame  92 , and a seat back  98  of bench  10 ″ is fixedly mounted to stationary frame  92 . The collective weight of seat  96  and seat back  98  is supported at all times by stationary frame  92 . When seat  96  of bench  10 ″ is rotated to a seating position, a pair of engagement members  102 , which are fixedly attached to seat  96 , support caster frames  90   a ,  90   b  suspended above floor surface FS by applying a lifting force to a pair of actuators  104  that are operatively connected to caster frames  90   a ,  90   b . This maintains a clearance C C  between casters  100  of caster frames  90   a ,  90   b  and floor surface FS. 
         [0064]    As in bench  10  and bench  10 ′, a suitable biasing component is operatively connected between stationary frame  92  and caster frames  90   a ,  90   b  of bench  10 ″ so as to bias stationary frame  92  in an upward direction relative to caster frames  90   a ,  90   b . In particular, bench  10 ″ is shown to include four compressed gas cylinder assemblies  106 . Locations of the four gas cylinder assemblies  106 , each housed within a pair of slidingly mated tube uprights  107 ,  109  of caster frames  90   a ,  90   b  and stationary frame  92 , respectively, are indicated in  FIG. 17 . A partial cutaway view of tube uprights  107 ,  109  is shown in  FIG. 17A , revealing components of the respective gas cylinder assembly  106 , namely, a piston  108  connected to caster frames  90   a ,  90   b  and a cylinder  110  connected to stationary frame  92 . Each cylinder assembly  106  provides a biasing force tending to extend its length by forcing an increasing length of piston  108  out of cylinder  110 . With reference to  FIG. 17A , cylinder  110  is connected to a bolt  111  affixed to tube upright  109  of fixed frame  92 , and a lower end of piston  108  abuts a caster beam  115   a  of caster frame  90   a . Bolt  111  is slidingly retained in a slot  113  formed in inner tube upright  107  of caster frame  90   a , thus permitting vertical movement of tube upright  107  and tube upright  109  relative to each other. Optionally, the length of slot  113  may serve to define one or both limits of a relative range of motion permitted between tube uprights  107 ,  109 . Alternatively, slot  113  may extend beyond limits set by other mechanical relationships within bench  10 ″. For example, as in the illustrated embodiment of bench  10 ″ as discussed further below, seat  96  in the seating position may abut an upwardly facing surface, preventing further downward pivoting of seat  96 , or a bottom face of tube upright  109  may abut caster beam  115   a  of caster frame  90   a , to prevent further downward travel of bolt  111  in slot  113  before bolt  111  reaches the bottom of slot  113 . Likewise, an internal stop (not shown) of cylinder assembly  106 , the weight of stationary frame  92  equaling or surpassing the extension force of cylinder assembly  106 , or some other stop mechanism, may prevent further upward travel of bolt  111  in slot  113  before bolt  111  reaches the top of slot  113 . As with benches  10 ,  10 ′, other suitable biasing components (not shown) may include, without limitation, solid state compression, tension, or torsion springs (such as a torsion bar), or magnets. 
         [0065]    Thus, to lift caster frames  90   a ,  90   b  from floor surface FS and lower stationary frame  92  into engagement with floor surface FS, engagement members  102  must bear the sum of the weight of caster frames  90   a ,  90   b  and the total biasing force from cylinder assemblies  106 , in turn transmitting these forces through seat  96  to stationary frame  92 . As with benches  10 ,  10 ′, to retain bench  10 ″ in this position, a sufficient moment must be applied to seat  96 , supplied either by the weight of an occupant sitting on seat  96  or by a suitable resistance or locking mechanism, to counterbalance the resultant moment about a seat pivot joint  112  ( FIG. 17 ) produced by the downward force of actuators  104  on engagement members  102 . 
         [0066]    One skilled in the art will understand that a partially-folded weight-shifting position of bench  10 ″, in which casters  100  and non-slip feet  94   a ,  94   b  contact floor surface FS simultaneously, and a partially folded engagement/loss-of-engagement position, in which engagement members  102  gain and lose contact with actuators  104 , substantially resemble those positions of bench  10 , depicted in  FIGS. 3 and 4 . Seat front pivoting leg member  62  and guide links  66  of bench  10  do not transmit any forces or relative motion between stationary frame  14  and caster frame  12 , and thus their omission in bench  10 ″ does not affect the stages of shifting the weight of bench  10 ″ between caster frames  90   a ,  90   b  and stationary frame  92 . 
         [0067]    Thus, bench  10 ″ is depicted only in a fully unfolded seating orientation ( FIGS. 12, 14-16, 20 ) and a fully folded mobile storage orientation ( FIG. 13 ). In the folded position of bench  10 ″ shown in  FIG. 13 , a clearance C F  is maintained between feet  94   a ,  94   b  and floor surface FS. As noted above, in this position stationary frame  92  floats above caster frames  90   a ,  90   b  on cylinder assemblies  106 . 
         [0068]    Additional components and features supporting the folding of bench  10 ″ between its seating and folded positions will now be described with reference to  FIG. 17 . Each actuator  104  comprises an actuator column  114  connected at its lower end to a respective caster frame  90   a ,  90   b , a lift bar  116  extending horizontally in a medial direction from the upper end of actuator column  114 , a low friction contact bushing  118  rotatably mounted on lift bar  116  to engage a respective engagement member  102 . Thus, as engagement members  102  pivot between the initial engagement position and the seating position, and the point of contact between engagement members  102  and bushings  118  shifts with respect to engagement members  102 , bushings  118  slidingly rotate around lift bar  116 . Bushings  118  thus prevent rubbing and wear between engagement members  102  and lift bar  116 . Also, it will be noted that engagement members  102  comprise a curved contact region  120  providing contact with bushings  118  throughout the engaged range of motion. The upward concavity of contact region  120  helps to maintain approximately vertical transmission of force to actuators  104  throughout the pivoting of the respective engagement member  102 . Also, as noted above for bench  10 , different force transmission components, such as pneumatics, hydraulics, magnets, or rack-and-pinion gear assemblies, for example, may be employed in lieu of a sliding normal contact engagement member to convert pivotal movement of seat  96  into relative vertical movement of caster frames  90   a ,  90   b  and stationary frame  92 , which may inherently avoid any potential problems associated with a varying direction of force transmission. 
         [0069]    Optionally, as in the illustrated embodiment, each actuator column  114  may be connected to caster frames  90   a ,  90   b  by a pivotal joint  122 , and slidingly retained in a sliding collar  124  fixed with respect to stationary frame  92 , collar  124  allowing column  114  some clearance to pivot but retaining column  114  in an approximately upright orientation. This connection arrangement of actuator column  114  permits column  114  to seek an angle in which the force transmission direction from engagement members  102  to actuators  104  is generally aligned with column  114 , to inhibit possible fatigue of column  114  due to repetitive bending stresses. 
         [0070]    In the illustrated embodiment, stationary frame  92  is constrained solely to vertical sliding movement relative to caster frames  90   a ,  90   b . This vertical sliding connection between caster frames  90   a ,  90   b  and stationary frame  92  is provided by smaller perimeter uprights  107  of caster frames  90   a ,  90   b  slidingly inserted into larger perimeter uprights  109  of stationary frame  92 . 
         [0071]    As mentioned above, when bench  10 ″ is in the seating position, a suitable locking mechanism may be employed to oppose or resist the tendency of cylinder assemblies  106  to extend, thereby forcing seat  96  to pivot upward and lifting stationary frame  92  off of floor surface FS. A passive locking mechanism is preferred, being capable of providing sufficient resistance to maintain bench  10 ″ in the seating position, but also capable of being disengaged by a sufficient lifting force applied to seat  96  without harming any components or requiring a separate action by a human operator, such as pulling out a pin or sliding a bolt before lifting. In addition, the passive locking mechanism preferably engages automatically when seat  96  is lowered to the seating position, without requiring an additional action such as inserting a pin or sliding a bolt. One such passive locking mechanism is a spring loaded ball detent locking mechanism  126   a ,  126   b  substantially resembling detent locking mechanism  47   a ,  47   b  described above for bench  10 . 
         [0072]    Stationary frame  92  includes a pair of seat leg beams  135  extending forwardly from a pair of uprights  137  of stationary frame  92  to the upper ends of fixed legs  95 . Seat leg beams  135  are integrally attached to respective upper ends of fixed legs  95 , which in turn are also attached near their lower ends to a pair of leg beams  139 . Seat leg beams  135 , thus supported on floor surface FS by stationary frame  92  and fixed legs  95 , serve to brace seat  96  in its generally horizontal seating position. In particular, a generally flat top surface  136  of seat leg beams  135  abuts a flat bottom surface of a seat base panel  141  of seat  96  when seat  96  is in the seating position, to support the weight of seat  96  and any occupants, and to prevent over-travel thereof in a downward pivoting direction. Preferably, seat base panel  141  is reinforced at the location of abutment against seat leg beams  135 , such as by plates  143 . 
         [0073]    Likewise, a stop mechanism is preferably provided to prevent seat  96  from pivoting upward beyond a desired limit, such as to maintain a clearance between a seat back shell  145  and a seat shell  148  (both described below), as in the fully folded position of bench  10 ″ shown in  FIG. 13 . For example, as illustrated in  FIG. 17B , a stop tab  144  may be affixed to a seat pivot bushing  149 , and a stop post  151  may be affixed to an inner upright  157  of stationary frame  92  to obstruct further pivoting of seat pivot bushing  149  when stop tab  144  meets stop post  151 . 
         [0074]    In addition to the components described in the above paragraphs, bench  10 ″ may incorporate any suitable combination of panels, contoured shells, cushions or other appropriate seat cover structure to promote ergonomics, comfort, and/or aesthetic appeal. For example, as illustrated in  12 - 16  and  18 - 20 , seat back  98  may include a seat back shell  145 , and seat  96  may include a seat shell  148 , each formed from any suitable material and attached in any suitable manner, as described above for bench  10 . Also similarly to bench  10 , notches  150  (shown in  FIG. 19 ) are preferably provided in a bottom front edge of seat back shell  145 , notches  152  (shown in  FIG. 15 ) in a bottom rear edge of seat shell  148 , and notches  153  in a seat bottom cover panel  155  to permit varying degrees of protrusion of members  102 , actuators  104 , and seat leg beams  135  into the interiors of seat back shell  145  and seat shell  148  as bench  10 ″ is folded and unfolded. 
         [0075]    In bench  10 ″ as depicted, a seat back panel  154  is sized and shaped to approximately match an open back side of seat back shell  145 , as illustrated in the exploded view of  FIG. 19 . Alternatively, a seat back panel resembling privacy panel  84  of bench  10 , having a substantial area extending above seat back shell  145 , may be employed. Illustrated in  FIG. 20  is an example arrangement of a booth  156  defined by a pair of benches  10 ″ as previously described, facing opposite sides of a table  158 . Advantageously, table  158  is itself mobile, being supported on standard locking casters  160 . Thus, the entire booth  156  may be moved away to facilitate cleaning or storage thereof, cleaning adjacent floor and wall surfaces, or rearranging the layout of a dining area. 
         [0076]    While the invention has been described with respect to certain embodiments, as will be appreciated by those skilled in the art, it is to be understood that the invention is capable of numerous changes, modifications and rearrangements, and such changes, modifications and rearrangements are intended to be covered by the following claims.