Patent Publication Number: US-8118375-B2

Title: Height adjustable desk configured for stacking with legs detached

Description:
This application claims priority from GB No. 09000040.7 on Jan. 3, 2009 
     FIELD OF THE INVENTION 
     The present invention relates generally to desks and, more particularly, to an improved to a desk having removable legs and which provides a method to stack up the desks in a pre-assembled configuration. 
     BACKGROUND 
     School desks having height adjustment means are known in the art and are useful in providing economical, versatile desks that can be used in first grade school classes as well as in adult classes. 
     Noticeable examples of the prior art are U.S. Pat. Nos. 2008/0136296A1, to Westbrook et Al. (2008), U.S. Pat. No. 6,843,183 B2, to Strong (2005), U.S. Pat. No. 5,107,775, to Langlais (1992), U.S. Pat. No. 4,437,411, to Maxwell (1984), and U.S. Pat. No. 3,794,397, to Flototto (1974). 
     While these prior art devices generally offer a school desk having height adjustment means, they also entail one or more of the following disadvantages. 
     First, when disassembled, they are generally cumbersome to manipulate and difficult to efficiently stack up in a stable space-saving manner for storage or shipping purposes; 
     Also, their height adjustment means are generally visible and, thus, render the desk somewhat less visually aesthetic. 
     Finally, in some cases, they generally comprise complex components that are relatively expensive to produce. 
     Against this background, there exist a need for a new and improved desk that avoids the aforementioned disadvantages. It is a general object of the present invention to provide a new and improved desk. 
     SUMMARY OF THE INVENTION 
     In a broad aspect, the invention provides a desk, the desk comprising: a writing board, the writing board defining a top surface and a substantially opposed bottom surface; at least three sleeves, each of the at least three sleeves extending substantially away from the bottom surface, each of the at least three sleeves defining a respective free end substantially opposed to the bottom surface; at least three legs, each of the at least three legs being removably insertable into and securable to a respective one of the at least three sleeves; a first one of the at least three sleeves defining a ridge extending substantially longitudinally therefrom at the free end of the first one of the at least three sleeves and a second one of the at least three sleeves defining a recess extending substantially longitudinally thereinto at the free end of the second one of the at least three sleeves, the recess being configured and sized for substantially snugly receiving the ridge. Two of the desks are stackable on top of each other with legs detached therefrom by inserting the ridge of a first one of the two desks into the recess of a second one of the two desks and inserting the ridge of the second one of the two desks into the recess of the first one of the two desks. 
     In another broad aspect, the invention provides a desk, the desk comprising: a writing board, the writing board defining a top surface and a substantially opposed bottom surface; at least three sleeves, each of the at least three sleeves extending substantially away from the bottom surface, each of the at least three sleeves defining a respective free end substantially opposed to the bottom surface; at least three legs, each of the at least three legs being removably insertable into and securable to a respective one of the at least three sleeves. The free end of a first one of the at least three sleeves is shaped substantially complementarily to the free end of a second one of the at least three sleeves such that, with the at least three legs removed from the at least three sleeves, when a first one and a second one of the desks are stacked on top of each other with the first one of the at least three sleeves of the first desk engaging the second one of the at least three sleeves of the second desk at their respective free ends, movements of the two desks relatively to each other in a direction substantially parallel to the writing boards of the two desks is substantially prevented. 
     In some embodiments of the present invention, the desk generally comprises a writing board, a substantially tray-shaped book box for holding learning materials, a plurality of substantially cylindrically-shaped sleeve inserts paired with a corresponding number of substantially elongated legs, with each leg typically terminated with a conventional furniture leg glide or end cap. 
     The tray-shaped book box has a substantially square or rectangular horizontal configuration that is generally defined by a bottom wall, a front end wall and a pair of oppositely disposed side walls. The rear end defines an opening through which a student can stowaway learning and/or writing materials. Each corner of the tray-shaped book box is provided with a substantially vertically oriented substantially tubular sleeve. 
     A suitable configuration of a plurality of corresponding through holes along a lower distal end portion of the sleeves of the book box and the sleeve inserts, in cooperative relation with a plurality of height adjustment holes along an upper portion of the leg members, allows a relatively fast and easy way of adjusting the height of the desk using conventional fasteners, such as screws. 
     Furthermore, the tubular lower end of the sleeves on each side of the front of the desk are provided with an outer substantially circumferential ridge, while the tubular lower end of the sleeves on each sides of the rear end of the desk are provided with a compatibly shaped inner substantially circumferential recess. 
     Thus, two pre-assembled book box and writing boards may be paired for efficient space saving storage and/or shipping purposes by turning a first pre-assembled book box upside down on a stable surface and then firmly engaging on top of its upwardly extending sleeves the compatibly shaped sleeves of a second pre-assembled book box, this one in an upstanding attitude and with its front end directed in an opposite direction relative to the first pre-assembled book box turned upside down. 
     Hence, a plurality of thus paired pre-assembled book boxes may in turn be efficiently and stably stacked one on top of the other. 
     To complete a full assembly of a desk, sleeve inserts are inserted through the lower open end of each sleeve of a pre-assembled book box, as described above, followed with the insertion of the top end of legs in the lower open end of the thus inserted sleeve inserts. Suitable fastener, such as screws, may then be used to rigidly fasten the thus coaxially assembled sleeves, sleeve inserts and legs such that the desk may have a desired height. 
     In some embodiments of the invention, at least one leg includes a leg member and a substantially tubular sleeve insert, the sleeve insert being insertable in one of the sleeves, the leg member being insertable in the sleeve insert. The leg member is provided with at least two substantially longitudinally spaced apart leg apertures extending substantially laterally thereinto, the sleeve insert being provided with a sleeve insert aperture extending substantially laterally thereinto. When the leg is attached to the sleeve, one of the leg apertures, the sleeve insert aperture and the sleeve aperture are substantially in register with each other a fastener is inserted through the leg apertures, the sleeve insert aperture and the sleeve aperture. Selection of different leg apertures to attach the leg to the sleeve vary a length of the leg. Advantageously, a single fastener is used to adjust the length of the leg and to attach the leg to the sleeve. This fastener is conveniently located substantially adjacent to the writing surface. Also, this structure is relatively robust. 
     Some advantages of the present invention are to provide a height adjustable desk which is relatively durable and relatively easy to assemble; whose configuration and pre-assembly mode allows for relatively efficient space saving for storage and shipping; whose unique and novel way of adjusting the height of the desk through portions of the integrally formed book box of the desk renders the latter visually aesthetic since the fastening means used to adjust the height of each leg is substantially concealed from view; and which is relatively simple and economical to produce. 
     Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A , in a front-top perspective view, illustrates a desk according to an embodiment of the present invention; 
         FIG. 1B , in a rear-top perspective view, illustrates the desk of  FIG. 1A ; 
         FIG. 2 , in an exploded front-top perspective view, illustrates the desk of  FIGS. 1A and 1B ; 
         FIG. 3 , in a rear-top perspective view, illustrates a book box part of the desk shown in  FIGS. 1A to 2 ; 
         FIG. 4 , in an enlarged partial view taken along section line IV of  FIG. 3 , illustrates the top end opening of a sleeve part of the desk shown in  FIGS. 1A to 2 ; 
         FIG. 5 , in a front-bottom perspective view, illustrates the book box shown in  FIG. 3 ; 
         FIG. 6 , in an enlarged partial view taken along section line VI of  FIG. 5 , illustrates the bottom end opening of a front-end sleeve of the book box shown in  FIGS. 3 and 5 ; 
         FIG. 7 , in an enlarged partial view taken along section line VII of  FIG. 5 , illustrates the bottom end opening of a rear-end sleeve of the book box shown in  FIGS. 3 and 5 ; 
         FIG. 8 , in an enlarged partial view taken along section line VIII of  FIG. 5 , illustrates an underside portion of a front end flange part of the desk shown in  FIGS. 1A to 2 ; 
         FIG. 9 , in a perspective view, illustrates a sleeve insert part of the desk shown in  FIGS. 1A to 2 ; 
         FIG. 10 , in a perspective view, illustrates a leg member part of the desk shown in  FIGS. 1A to 2 ; and 
         FIG. 11 , in a perspective view, illustrates two book boxes such as the book boxes shown in  FIGS. 3 and 5 , the book boxes being shown in an oppositely disposed, storage configuration, where both book boxes are engaged through the lower ends of their sleeves. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A ,  1 B and  2  best show the various aspects of an embodiment of a desk  10  according to the present invention. Referring to  FIG. 1A , the desk  10  is usable as a school desk, but other uses are within the scope of the present invention. The desk  10  generally comprises a writing board  12 , a substantially tray-shaped book box  14  for holding learning materials, a plurality of cylindrically-shaped and substantially tubular sleeve inserts  16  paired with a corresponding number of elongated leg members  18 . Each leg members  18  is typically terminated with a conventional furniture leg glide or end cap  20 . 
     The writing board  12  is represented by a substantially rigid and planar element that may be constructed of a single molded material, a lamination of wood products and melamine laminates, or a variety of other materials. The writing board  12  defines a top surface  22  and a substantially opposed bottom surface  23 . In some embodiments, the top surface  22  of the writing board  12  may be provided with an elongated groove  24  generally disposed in a parallel fashion along an edge  26  of the writing board  12  that generally represents the front end  42  of the assembled desk  10 . Elongated groove  24  is suitably configured to stably hold in place an horizontally disposed pen or pencil laid therein when not in use, or to prevent such writing tools from freely rolling off the top surface  22  of the desk  10 . 
     The writing board  12  is suitably sized and shaped such that its peripheral edges typically slightly protrude the overall horizontal cross-section of the underlying book box  14 , described hereinafter. 
     Referring for example to  FIG. 3 , in some embodiments of the invention, the tray-shaped book box  14  is represented by an integrally formed one piece element comprising a substantially square or rectangular shaped bottom wall  28  delimited by a front end wall  30  and a pair of oppositely disposed side walls  32 . The bottom wall  28  is preferably provided with structural reinforcement rib patterns, such as the longitudinally disposed elongated ribs  34 , to help support relatively heavy books that may be stored thereon.  FIG. 5  illustrates some of these aspects from a different perspective. 
     The book box  14  further comprises at least three, but typically four substantially cylindrically-shaped sleeves  36  disposed along a generally vertical axis at each corner of the book box  14 . Each sleeve  36  therefore extends at the periphery of the book box  14 . Each sleeve  36  extends substantially away from the bottom surface  23  and is substantially perpendicular to the writing board  12 . 
     Peripheral ledges  38  are laterally outwardly extending from the upper edges of the front and side walls  30  and  32  respectively. The peripheral ledges  38  are provided with a plurality of vertical through holes  40  and cooperatively define a substantially planar fastening structure for stably fastening the book box  14  to the underside of the writing board  12  using any suitable means such as, for example, screws  41 , or the like (as illustrated in  FIG. 2 ). 
     The integrally formed book box  14  is preferably made of a suitably rigid material such as plastic using a conventional injection molding process. 
     Returning to  FIG. 3 , the front end wall  30  of the book box  14  generally represents the front end  42  of the assembled desk  10 , while the opposite, open end of the book box  14  generally represents the rear end  44  of the assembled desk  10  through which learning and/or writing materials may be stowed away in the interior space defined therein. 
     In some embodiments of the invention, an elongated open tray  45 , for holding writing tools or the like, is integrally formed along an inner bottom edge of the open rear end  44  of the book box  14 . 
       FIG. 8  shows a plurality of elongated lips  46  perpendicularly downwardly projecting from the underside of the ledge  38 , adjacent the front end wall  30 , and generally disposed in a substantially parallel fashion relative to the latter. In turn, each elongated lip  46  is provided with a plurality of relatively small and perpendicularly inwardly projecting notches or flanges  47 . Inwardly projecting flanges  47  have their distal ends extend suitably close along the surface of front end wall  30  such that the elongated straight edge of a sheet of paper, a relatively thin cardboard, or the like (not shown), may be slided upwardly there between and held in place in a tight-fit relation. Thus, the elongated lips  46  and notches  47 , in cooperative relation with the front end wall  30 , may conveniently form a clip element extending away from the bottom surface  23  of the writing board  12  (both not seen in  FIG. 8 ) and used to hold in place a piece of paper on which may be inscribed, for example, the name of the student occupying the desk, the name of a class team, the title of a school program, or the like. 
     As best illustrated in  FIGS. 6 and 7 , the sleeve  36  at each corner of the book box  14  defines a sleeve outer surface  48  a sleeve inner surface  50 . The sleeve inner surface  50  defines a substantially cylindrical passageway  51  having an upper end  52 , as shown in  FIG. 4 , and a lower end  54 , as best shown in  FIGS. 6 and 7 . The upper end  52  of the sleeves  36  preferably coincides with the peripheral ledges  38  defining the upper end of the book box  14 , while the lower end  54  of the sleeves  36  may slightly perpendicularly protrude from the underside surface of bottom wall  28  of the book box  14 , as best illustrated in  FIG. 5 . The lower end  54  is therefore a free end of the sleeve  36 . 
     The thus downwardly protruding portion of the lower end  54  is provided with a sleeve aperture  56  leading substantially laterally thereinto between the sleeve inner and outer surfaces  48  and  50 . The sleeve aperture  56  is therefore substantially adjacent the free end of the sleeve  36 . The purpose of the sleeve aperture  56  will be explained in cooperative relation with a preferred mode of assembly of the leg members  18  with the book box  14 , which will be described in more details below. The sleeve aperture  56  is disposed through an inwardly oriented portion of the sleeve outer surface  48 , as best illustrated in  FIG. 7 . 
     As better seen in  FIG. 4 , the upper end  52  of each sleeve  36  is provided with an optional, and relatively small slot  58  located, here again, at an inwardly oriented portion of the sleeve outer surface  48  of the sleeve  36 , as best illustrated in  FIG. 4 . Slot  58  may be optionally used for future alternate versions of sleeve inserts (not shown). 
     As best shown in  FIG. 6 , the sleeve inner surface  50  is typically provided with a plurality of circumferentially distributed elongated ribs  60  that are longitudinally extending substantially the whole length of each sleeve  36 . Elongated ribs  60  help ease the insertion of a sleeve insert  16  in the sleeve  36 . 
     Furthermore, the lower ends  54  of the pair of sleeves  36  on each side of the front wall  30  of the book box  14  have a different distal end configuration compared to the lower ends  54  of the pair of sleeves  36  on each side of the open rear end  44 . Thus, the pair of sleeves  36 , parallelly disposed on each side of the front end wall  30  of the book box  14  are both provided with an outer circumferential groove  62 , and therefore define a substantially annular ridge  63  extending substantially away from the sleeves  36 , as shown in  FIG. 6 , while the lower ends  54  of the pair of sleeves  36  parallelly disposed on each side of the rear open end  44  are both provided with an inner circumferential groove  64 , as shown in  FIG. 7 , the groove  64  being a substantially annular recess extending substantially longitudinally into the sleeves  36 . the inner circumferential groove  64  is configured and sized for substantially snugly receiving the ridge  63 . 
     The outer circumferential groove  62  of the pair of lower ends  54  at the front end  42  of the desk are compatibly shaped to be engageable with the inner circumferential grooves  64  of the pair of lower ends  54  at the rear open end  44  of the desk. It is to be understood that the compatibly shaped circumferential grooves  62  and  64  may be inversely disposed relative to the front and rear end of the desk or can be laterally opposed. The purpose of the compatibly shaped inner and outer circumferential grooves  62  and  64  respectively will be explained in cooperative relation with a convenient stacking method of the book boxes  14 , which will be described more below. 
       FIG. 9  shows a sleeve insert  16  that is represented by a substantially tubular hollow member that is preferably made of a suitably rigid material such as, for example, metal, a suitably rigid plastic, or the like. Sleeve insert  16  is generally defined as having an insert upper end  66 , an insert lower end  67 , an outer cylindrical surface  68  and an inner cylindrical surface  69 . Sleeve insert  16  has a pair of longitudinally spaced apart, adjacent through holes  70  and  71 , also referred to as sleeve insert apertures, that extend laterally through outer surface  68  that is relatively near the insert lower end  67  of the sleeve insert  16 . Both through holes  70  and  71  typically have equivalent diameters. 
     Sleeve insert  16  has an overall length that is preferably slightly longer than the overall length of the sleeves  36  of the book box  14  described above, and a diametrical cross-section that is suitably sized such that it may be fully inserted, preferably in a snug-fit relation, through either the upper end  52 , or lower end  54 , of a sleeve  36 , with its insert lower end  67  thereof oriented downwardly relative to the book box  14 . Thus, once a sleeve insert  16  is inserted in a sleeve  36 , as described above, with its insert upper end  66  that is substantially at level with the upper end  52  of sleeve  36 , a relatively short lower portion of the sleeve insert  16  is protruding from the lower end  54  of the sleeve  36 , as best illustrated in  FIGS. 1A and 1B . 
     Once a sleeve insert  16  is thus inserted in a sleeve  36 , as described above, through hole  70  is suitably disposed along the insert lower end  67  of sleeve insert  16  such that it may be centered relative to sleeve aperture  56  at the lower end  54  of sleeve  36 . In turn, adjacent through hole  71  is thus longitudinally disposed along the portion of sleeve insert  16  that is protruding from the lower end  54  of sleeve  36 . 
     IN some embodiments of the invention, sleeve apertures  56  near the lower open end  54  of sleeves  36 , may have a slightly larger diameter than through holes  70  and  71  near the insert lower end  67  of sleeve insert  16 . 
       FIG. 10  shows a leg member  18  that is represented by a substantially elongated and cylindrical hollow member having an upper end portion  74  and a lower end portion  76 . The upper end portion  74  has a cross-sectional diameter that is suitably sized to be inserted telescopically, and preferably in a snug-fit relation, through sleeve insert  16 , as seen in  FIG. 1B  for example. 
     The upper end portion  74  is provided with a plurality of lateral extending threaded leg apertures  80  that are equidistantly spaced apart and longitudinally aligned along the general axis of the leg member  18 . The leg apertures  80  have a diameter that is relatively smaller than the diameter of the sleeve apertures  56  and through holes  70  and  71  of the sleeve  36  and sleeve insert  16  respectively. Furthermore, the distance between two adjacent holes  80  of the leg corresponds to the distance between the pair of through holes  70  and  71  of the sleeve insert  16  described above. Thus, when the upper end portion  74  of a leg member  18  is inserted through the insert lower end  67  of a sleeve insert  16 , the pair of through holes  70  and  71  of the sleeve insert  16  can be simultaneously aligned with a pair of leg apertures  80  in the leg member  18 . 
     The peripheral edge of the leg apertures  80  is preferably slightly recessed to ease the alignment of fastening elements, such as threaded screws  81 , when fastening the leg members  18  to the desk  10 , as it will be described more below. The plurality of leg apertures  80 , in cooperative relation with a suitable threaded fastening element, such as a threaded screw  81  (as illustrated in  FIG. 2 ), serve as a means to adjust the height of the desk  10 , as it will be described in more details hereinbelow. Leg member  18  is typically made of a suitably rigid material such as, for example, metal, a suitably rigid plastic, a fiber reinforced plastic (FRP), or the like. 
     As mentioned above, the distal lower end  78  of the leg member  18  is preferably terminated with a conventional furniture leg glide or end cap  20  (as shown in  FIGS. 1A ,  1 B and  2 ). 
     Leg member  18  is of a suitable length, and the number and disposition of its leg apertures  80  along upper end portion  74  are such that, when the height adjustable desk  10  is assembled, such as illustrated in  FIGS. 1A and 1B , the height of the desk may be suitably adjusted to accommodate students of different heights. In other words, the height adjustable desk  10  of the present invention can be easily adjusted to accommodate students in primary school, high school and adult classes. 
     The leg member  18  and the sleeve insert  16  together form a leg  17  that is removably insertable into and securable to the sleeve  36 . The through hole  70  is therefore a leg aperture positionable substantially in register with the sleeve aperture  56 . 
     In a preferred method of pre-assembly and storage configuration of the height adjustable desk  10  for efficient space saving storage or shipping purposes, at least two book boxes  14  are each pre-assembled with their corresponding writing board  12  using any suitable fastening means such as screws  41 . 
     Hence, as illustrated in  FIG. 11 , a pair thus pre-assembled book boxes  14  and writing boards  12 , denoted by reference numerals  90  and  92 , may be efficiently and stably stacked one on top of the other in an oppositely deposed configuration as described hereinafter. The first pre-assembled book box  90  is turned upside down on a stable surface, with the lower ends  54  of its sleeves  36  pointing upwardly. Next, the second pre-assembled book box  92  is stacked upright on top of the first book box, with its front end wall  30  facing in an opposite direction relative to the front wall  30  of the first book box, and the lower ends  54  of its four sleeves  36  oppositely corresponding with the four lower ends  54  of the first book box  14 . 
     Thus, the pair of lower ends  54  of the sleeves  36  on each sides of the front end wall  30  of the first pre-assembled book box  90  stably engage with the compatibly shaped lower ends  54  of the sleeves  36  on each sides of the rear open end  44  of the second pre-assembled book box  92 . Inversely, the pair of lower ends  54  of the sleeves  36  on each sides of the front end wall  30  of the second pre-assembled book box  92  stably engage with the compatibly shaped lower ends  54  of the sleeves  36  on each sides of the rear open end  44  of the first pre-assembled book box  90 . In other words, the pre-assembled book boxes  90  and  92  are stackable on top of each other by inserting the ridges  63  of the book box  90  into the inner circumferential grooves  64  of the book box  92 . 
     A plurality of pairs of pre-assembled book boxes  90 ,  92  thus stacked as described above may, in turn, be stably stacked one on top of the other for efficient mass storage and shipping purposes. 
     To complete the assembly of a desk  10 , a set of four leg members  18  have their upper end portion  74  inserted in the insert lower end  67  of a corresponding number of sleeve inserts  16  until the through hole  71  of the sleeve insert  16  is aligned with a suitable leg aperture  80  of the leg member  18  such that the total length of the thus assembled sleeve insert  16  and leg member  18  roughly corresponds to the desired height of the desk  10 . The leg  17  thus assembled is therefore telescopic. A suitable fastening element, such as a threaded screw  81 , is then fastened through the corresponding through hole  71  and leg aperture  80  of the thus assembled sleeve inserts  16  and leg members  18  respectively. 
     Next, the insert upper end  66  of a sleeve inserts  16  thus fastened to its respective leg member  18 , is inserted in the lower open end  54  of each of the four sleeves  36  of a pre-assembled book box  14  and writing board  12 , as described above, such that the through hole  71  of the sleeve insert  16  is aligned with the sleeve aperture  56  of the sleeve  36 . A threaded fastening element, such as a threaded screw  81 , having a head  83  defining a head diameter slightly smaller than the diameter of sleeve aperture  56  but greater than through hole  70 , may then be fastened through the thus corresponding sleeve apertures  56 , through hole  70  and leg aperture  80  of the sleeve  36 , the sleeve insert  16  and leg member  18  respectively. The threaded screw  81  may be fastened until the head  83  of the latter abuts against the surrounding surface of the relatively smaller through hole  70  of the sleeve insert  16  in order to firmly secure the leg member  18  to the desk  10 . Thus, the head  83  of the threaded screw  81  serves as a locking means within sleeve aperture  56 , in order to retain the sleeve insert  16  and leg member  18  assembly within sleeve  36 . 
     Furthermore, the head  83  of the threaded screw  81  used to fasten the leg member  18  to the desk  10  is received and substantially concealed within the depth of the relatively larger sleeve aperture  56  provided through the sleeve  36  for preventing hand or finger injuries of, for example, students who may manipulate the desk  10 . 
     In an alternate embodiment, lateral through hole  71  is not present through the lower portion of sleeve insert  16  such that only through hole  70  is used to adjust the height as well as fasten the leg member  18  to the book box  14 , in cooperative relation with a sleeve insert  16  and a threaded screw  81 . In the present embodiment, the method of assembly slightly differs compared to the first embodiment described above in that a sleeve insert  16  is first inserted, insert upper end  66  first, through the lower end  54  of each sleeve  36  of a pre-assembled book box  14  and writing board  12 , with through hole  70  of the sleeve insert  16  carefully aligned with the corresponding sleeve aperture  56  of the sleeve  36 . A leg member  18  is then inserted, upper end portion  74  first, through each insert lower end  67  of the sleeve inserts  16  thus positioned within the sleeves  36  of the desk, until a suitable leg aperture  80  of the leg member  18  is in turn aligned with the already corresponding sleeve aperture  56 , through hole  70  and leg aperture  80 . Finally, a threaded screw  81  is fastened through sleeve apertures  56 , through hole  70  and leg aperture  80 . 
     Although the above description contains many specificities, these should not be construed as limitations on the scope of the invention but is merely representative of the presently preferred embodiments of this invention. For example, the desk  10  may have any other suitable configuration than the conventional square or rectangular desk configuration. For examples, the desk  10  may have an oval, an hexagonal, an L-shaped configuration, or the like, and provided with a suitable number of legs  17  to offer a stable desk. Furthermore, the correspondingly shaped cross-sections of the cylindrical sleeves  36 , sleeve inserts  16  and leg members  18  may as well have any other compatibly-shaped cross-section configuration such as, for examples, square, rectangular, hexagonal, oval or the like. 
     Also, while a specific configuration of the ridge  63  and recess formed by the inner circumferential groove  64  has been described hereinabove, some objects of the present invention can be achieved by having a free end of a first sleeve  36  that is shaped substantially complementarily to a free end of a second sleeve  36  such that when two pre-assembled book boxes  90  and  92  are stacked on top of each other with the free end of the first sleeve  36  engaging the free end of the second sleeve  36 , movements of the two desks relatively to each other in a direction substantially parallel to their writing board  12  is substantially prevented. 
     Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.