Patent Publication Number: US-2022211204-A1

Title: Modular Christmas tree

Description:
FIELD OF THE INVENTION 
     The present invention relates to a modular Christmas tree. In particular, the present invention relates to a modular Christmas tree comprising parts that may be assembled to form an artificial Christmas tree, and subsequently disassembled and stored compactly. 
     BACKGROUND TO THE INVENTION 
     Artificial Christmas trees traditionally comprise a stand, an artificial trunk and artificial branches provided with artificial needles so as to mimic the appearance of a real Christmas tree. Usually the artificial Christmas tree can be at least partly disassembled or folded into a more compact configuration for storage. However, such traditional artificial Christmas trees are still bulky in their stored states and require a substantial volume. This problem is exacerbated by the seasonal nature of Christmas trees, as they are stored for around eleven months of the year. In addition, such artificial Christmas trees make extensive use of PVC which is not environmentally friendly. 
     Some artificial Christmas trees have non-traditional designs. For example, US Design Patent No. 832133 shows an artificial Christmas tree with a base, a central vertical support akin to a trunk, and a series of tiers that figuratively mimic branches. Each tier comprises a set of three battens arranged in the shape of a six-armed asterisk when viewed from above, with their centres crossing at the vertical support. The tiers are spaced apart vertically, and the tiers get progressively wider from top to bottom to give the artificial Christmas tree a tapering shape. 
     US Design Patent No. 624452 shows another non-traditional Christmas tree. The tree has a base, a central vertical support akin to a trunk and a series of battens placed one above another with only a small separation. The centres of the battens coincide with the vertical support and each batten is rotated slightly relative to the preceding batten to form a helical shape. The length of the battens progressively lengthens from top to bottom to give the tree a tapering shape. 
     SUMMARY OF THE INVENTION 
     Against this background, and from a first aspect, the present invention resides in a modular Christmas tree comprising three or more side structures that is configured to rise from a supporting surface such as a floor, wherein the three or more side structures are arranged obliquely to give the modular Christmas tree a tapering shape that widens from top to bottom. The tree further comprises a plurality of central support structures that extend outwardly to support the three or more side structures. The plurality of central support structures increase in width from the top to the bottom of the modular Christmas tree to follow the tapering shape of the modular Christmas tree. 
     Each side structure comprises a series of elongate pieces joined together with connectors that allow the series of elongate pieces to be separated for storage of the disassembled Christmas tree. The series of elongate pieces include an uppermost elongate piece, intermediate elongate pieces and a lowermost elongate piece. The elongate pieces are joined to each other by the connectors such that their ends overlap at overlapping portions to form a zigzag shape (with long legs of the zigzag running along each elongate piece and short legs of the zigzag running across the elongate pieces through the overlapping portions). The connectors are provided at the overlapping portions. 
     The plurality of central support structures includes an upper central support structure and one or more lower central support structures. The upper central support structure comprises an upper hub having joint surfaces disposed around its sides with a joint surface for each of the three or more side structures. 
     Each of the one or more lower central support structures comprises a lower hub having joint surfaces disposed around its sides with a joint surface for each of the three or more side structures. Each of the one or more lower central support structures also comprises a number of radially-extending spokes corresponding to the number of side structures. Each joint surface is joined to an end of a spoke with a connector being provided to allow the spoke to be joined to the associated joint surface of the lower hub when the tree is being assembled and separated from the associated joint surface of the lower hub when the tree is being disassembled. Each spoke supports, at its other end, an intermediate elongate piece of a side structure with a connector being provided to allow the intermediate elongate piece to be joined to the associated spoke when the tree is being assembled and separated from the associated spoke when the tree is being disassembled. 
     The upper central support structure may or may not comprise a number of radially-extending spokes corresponding to the number of side structures like the at least one lower central support structure. Each joint surface of the upper hub may be joined to the uppermost elongate piece of its associated side structure directly or may be joined to the uppermost elongate piece of its associated side structure indirectly via radially-extending spokes. 
     In this way, the modular Christmas tree employs a limited number of components held together by connectors to create a life-sized three-dimensional structure corresponding to a simplified, yet clearly identifiable Christmas tree. Moreover, the side structures of the modular Christmas tree may be equally separated in angle such that the modular Christmas tree retains its characteristic shape when viewed from any angle (for example, the tree may have five side structures arranged at 72° intervals). The components may be simple in design and assemble in a modular fashion. When assembled, the components form a sturdy structure which is of similar height to real Christmas trees (such as domestic use Christmas trees found in homes) and occupies a similar floor space. Advantageously, the disassembled components can be stored in a compact manner and occupy a volume that is considerably smaller than the storage requirement of similar-sized artificial Christmas trees. 
     Further optional features of the modular Christmas tree will now be described. 
     As mentioned above, each joint surface of the upper hub may support the uppermost elongate piece of its associated side structure with a connector being provided to allow the uppermost elongate piece to be joined directly to and separated from the associated joint surface of the upper hub. Hence, the upper central support structure may not include any spokes, in contrast with the lower central support structures. This ensures a narrow top to the modular Christmas tree, and contributes to the tapering shape of the Christmas tree. 
     Alternatively, the upper central support structures may further comprise a number of radially-extending spokes corresponding to the number of side of structures, like the lower central support structures. Each joint surface of the upper hub may be joined to an end of a spoke with a connector being provided to allow the spoke to be joined to the associated joint surface when the tree is being assembled and separated from the associated joint surface when the tree is being disassembled. Each spoke supports, at its other end, an uppermost elongate piece of a side structure with a connector being provided to allow the uppermost elongate piece to be joined to the associated spoke when the tree is being assembled and separated from the associated spoke when the tree is being disassembled. The spokes may be short in length and positioned away from the upper ends of the uppermost elongate pieces of the side structures such that the uppermost elongate pieces may still meet at a point at the top of the tree, or end in close proximity to one another. 
     Advantageously, the hubs of the central support structures are aligned vertically along a central vertical axis of the modular Christmas tree, and the radially-extending spokes of each central support structure have the same length which spans from the central hub to join to the side structures. While the spokes within a central support structure may be the same, the spokes may differ between central support structures. For example, in order to form the tapering shape of the modular Christmas tree, the length of the spokes the central support structures may increase from the top to the bottom of the modular Christmas tree (where the tree comprises at least two central support structures comprising radially-extending spokes). The spokes of each central support structure may be the same, i.e. of a common design. Such commonality helps reduce manufacturing time and costs. The spokes of different central support structures may be of a similar design, with just their lengths varied. For example, the ends of each spoke may be the same and may comprise the same configuration to allow connection to a hub and side structure, with just the length of a plain central section being varied. For instance, each spoke may have one vertical end face to mate with a joint surface of a hub, and may have an oblique end surface to mate with an angled side of an elongate piece of a side structure. 
     Many different types of connectors for the various joints may be used. Advantageously, the same type of connector may be used for all, or the majority of the joints. For example, simple dowelled butt joints may be used for all or some of the joints. The dowelled butt joint may comprise one or more simple dowels. Each dowel is received in holes provided in the two components to be joined. The size of the holes may correspond to that of the dowel, such that a snug fit is achieved. The snug fit should allow relatively easy joining and separating of the two components, yet provide the required structural integrity of the assembled Christmas tree. The holes may have a tapering shape so as to be wider at their opening than at the bottom of the hole. The size at the bottom of the hole may correspond to width size of the dowel. This tapering may be gradual or may be stepped. For example the hole may comprise two steps and hence three sections of narrowing size as the hole deepens. The tapering may be 5% or less of the width on the opening of the hole. This provides greater tolerance when inserting the dowel into the hole and also eases separation of the joint when disassembling the Christmas tree. The dowels may be wooden or metal, and may be circular in cross section (when viewed from the end), although other shapes may be used such as square, rectangular, oval and race-track shaped. The same size dowel may be used for multiple joints or even for all joints, as this reduces manufacturing time and costs. 
     Hence, where the upper hub is joined directly to the uppermost elongate pieces, each connector provided between the upper hub and an uppermost elongate piece may comprise a dowel seated within a hole provided in the joint surface of the upper hub and an aligned hole provided in the uppermost elongate piece. Also, or in the alternative, each connector provided between a lower hub and a spoke may comprise a dowel seated within a hole provided in the joint surface of the lower hub and an aligned hole provided in the end of the spoke. Each connector provided between a spoke and an elongate piece may comprise a dowel seated within a hole provided in the other end of the spoke and an aligned hole provided in the elongate piece. Each of the joints described in this paragraph may comprise a single dowel received in a single pair of aligned holes or alternatively two dowels received in two pairs of aligned holes, which provides greater rigidity to the joint. 
     To provide greater structural integrity for the assembled Christmas tree, each connector provided at the overlapping portions of two elongate pieces may comprise a pair of dowels seated within respective pairs of aligned holes provided in the elongate pieces. Each pair of dowels may be separated along the length of the associated overlapping portion. 
     As an alternative to simple dowelled butt joints comprising a plain dowel received in corresponding holes, more complex dowelled butt joints may be formed. For example, any of the connectors may comprise of a cam nut and cam dowel. In such arrangements, the cam dowel is screwed into one of the components and its head is received in a hole provided in the other component. The hole terminates in a chamber housing the cam nut such that the head of the cam dowel is received within the cam nut. The chamber extends to a side of the components to provide access to the cam nut. Rotating the cam nut causes a cam surface of the cam nut to tighten against the head of the cam dowel, thereby pulling the components together and securing the joint. For example, each connector provided at the overlapping portions of the elongate pieces may comprise (1) a dowel seated within respective pairs of aligned holes provided in the elongate pieces and (2) a cam nut and cam dowel. Then, the cam dowel may be screwed into one of the elongate pieces and its head is received in a hole provided in the other of the elongate pieces. Rotating the cam nut causes the cam surface of the cam nut to tighten against the head of the cam dowel, thereby securing the elongate pieces together. 
     The angle between adjacent spokes may be the same for all pairs of adjacent spokes, to meet the side structures that are also separated by equal angles. This provides a pleasing symmetry to the modular Christmas tree. 
     As mentioned above, using a common design for multiple components of the modular Christmas tree is advantageous as it reduces manufacturing time and costs. It also aids in assembly of the modular Christmas tree as less skill is required on the part of the assembler in discriminating between similar yet distinct parts. 
     To this end, the hubs may share a common design. This may be true even for the upper hub of the upper central support structure that my join directly to the uppermost elongate pieces and also for the lower hub(s) of the lower central support structure(s) that join to spokes. The hubs may have a horizontal cross section in the shape of a regular polygon, with the number of sides of the polygon equaling the number of side structures. Other arrangements are possible. For example, the hubs may have twice as many sides as the number of side structures. This may be advantageous as it allows a common design to be used where a manufacturer offers different designs of modular Christmas tree. Six-sided and three-sided modular Christmas trees may be provided, where each side of hexagonal hubs are used in the six-sided trees and alternate sides of the hexagonal hubs are used for the three-sided trees. 
     The intermediate elongate pieces may share a common design, and the lowermost elongate pieces may share a common design which may or may not be the same as that of the intermediate elongate pieces. The uppermost elongate pieces may share a common design which may or may not be the same as that of the intermediate elongate pieces. 
     The modular nature of the Christmas tree lends itself well to the provision of trees of different heights. For instance, the number of intermediate elongate pieces in each side structure may be varied to alter the height of the tree. The elongate pieces occupying the same height in a tree may be considered as a “level” of the tree, and hence the height of a tree may be varied by adjusting the number of levels. Hence, a manufacturer may simply manufacture a common design of elongate pieces, and provide different number of elongate pieces according to the height of tree required. Similarly, an owner may build a modular Christmas tree to different heights, for example making a shorter tree if desired or needed (for example, following a move to a smaller home). 
     Different number of levels may require different numbers of central support structures. For example, the modular Christmas tree may comprise a number of tiers, each tier comprising two levels of elongate pieces and a central support structure. Hence, for each side structure, the series of joined elongate pieces may alternate between elongate pieces supported by a support structure and elongate pieces not supported by a support structure. This would provide the following designs: (i) a tree with three intermediate elongate pieces, and an upper central support structure and one lower central support structure; (ii) a tree with five intermediate elongate pieces, and an upper central support structure and two lower central support structures; and (iii) a tree with seven intermediate elongate pieces, and an upper central support structure and three lower central support structures. 
     In addition, a manufacturer may provide different number of elongate pieces, spokes and different hub designs according to the number of sides required. This allows modular Christmas trees having a range of numbered sides and, independently, a range of different levels or tiers (and hence heights) to be supplied. For example, a manufacturer could hold a stock of a common design of uppermost elongate pieces, a common design of intermediate and lowermost elongate pieces, pentagonal, hexagonal and octagonal hubs, and spokes of three different lengths, and dowels, making nine components in total. This allows trees having three, four, five, six and eight sides, and trees having two, three of four tiers. Hence, a stock of nine components allows fifteen different designs of tree. Even more designs are possible if tiers having more than two levels of elongate pieces are used. 
     This also provides benefits to the owner of a modular Christmas tree. The owner may omit one or more sides, for example to allow the tree to be placed closer to a wall or up against a wall. Also an owner may use fewer side structures if desired, for example such that a six-sided tree may be built as a three-sided tree. Other changes may be made to a tree requiring just some components to be purchased rather than another complete tree. For example, a user wishing to change a five-sided tree into a four-sided tree with evenly space sides may simply purchase new hubs. Conversely, a user wanting a tree with more sides may purchase just the side pieces required for each additional side structure and possibly new hubs. 
     Optionally, the hubs, spokes and elongate pieces are made from wood, either hard wood or soft wood. This is more environmentally friendly than the plastics used in many artificial Christmas trees. The connectors may also be made from wood, such as wooden dowels. Metal parts may be used, for example for the cam nut and dowels mentioned above, as this avoids the negative environmental issues associated with the use of plastics. 
     Further optional features will become evident to the person skilled in the art upon reading the following detailed description of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention can be more readily understood, reference will now be made by way of example only, to the accompanying drawings in which: 
         FIGS. 1 and 2  are perspective views of an assembled artificial Christmas tree; 
         FIG. 3  is a top view of the artificial Christmas tree of  FIGS. 1 and 2 ; 
         FIG. 4  is a perspective view of part of the artificial Christmas tree of  FIGS. 1 to 3 , showing two levels of the tree; 
         FIG. 5  are top, side and bottom views of an intermediate elongate piece of the artificial Christmas tree of  FIGS. 1 to 3 ; 
         FIG. 6  are top, side and bottom views of an uppermost elongate piece of the artificial Christmas tree of  FIGS. 1 to 3 ; 
         FIG. 7  are top and side views of a hub of the artificial Christmas tree of  FIGS. 1 to 3 ; 
         FIG. 8  are top, side and bottom views of a spoke of the artificial Christmas tree of  FIGS. 1 to 3 ; 
         FIG. 9  is a side view of an assembled side of the artificial Christmas tree of  FIGS. 1 to 3 ; 
         FIG. 10  is a top view of an assembled central support structure of the artificial Christmas tree of  FIGS. 1 to 3 ; 
         FIG. 11  is a perspective view of the artificial Christmas tree of  FIGS. 1 to 3  when disassembled and packed into a storage box; 
         FIGS. 12 to 16  are perspective views of an assembled artificial Christmas trees of different designs having varying numbers of sides, levels and central support structures; 
         FIGS. 17 and 18  are a side view and detail of an alternative connector for joining the side pieces; and 
         FIGS. 19 and 20  are side views of an alternative connector for joining the side pieces. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A modular, artificial Christmas tree  10  is shown in  FIGS. 1 to 3 . The Christmas tree  10  has five sides  12  (also referred to herein as side structures), and each side  12  has a zig-zag shape. The sides  12  are angled such that the Christmas tree  10  has a tapering shape with a wide base and a narrow top. The example Christmas tree  10  of  FIGS. 1 to 3  is approximately 1.5 m tall and has a base diameter of approximately 1.2 m. 
     The modular Christmas tree  10  does not have a central trunk, and is instead supported on the floor by its five sides  12 . Three central support structures  14  support the sides  12  at different heights, and provide rigidity to the Christmas tree  10 . The tree  10  has a central vertical axis  11  that is indicated in the figures. The central support structures  14  are arranged centrally with respect to this axis  11 , and extend outwardly from the axis  11 . 
     The five sides  12  of the Christmas tree  10  meet at the top of the tree  10  and extend downwardly as a series of overlapping side pieces  16 . Each side piece  16  is elongate. The side pieces  16  are oblique rather than being vertical, hence contributing to the tapering shape of the Christmas tree  10 . The ends of the side pieces  16  overlap at overlapping portions to give each side  12  its zig zag shape. Where two side pieces  16  meet, the higher side piece  16  is positioned inside (i.e. closer to the central axis  11  of the tree  10 ) than the lower side piece  16 . Each side  12  comprises four intermediate side pieces  16   b  that are joined to other side pieces  16  at both ends. Each side  12  also comprises a bottom side piece  16   c  which is joined to an intermediate side piece  16   b  at one end and rests upon the floor at its other end. This other end is angled relative to the length of the bottom side piece  16   c  such that the entire other end rests against the floor. Finally, each side  12  also has a top side piece  16   a  which is joined to an intermediate side piece  16   b  at one end and is supported by an upper central support structure  14   a  its other end. 
     The upper central support structure  14   a  comprises a hub  18  which is positioned with its centre positioned on the central axis  11  of the tree  10 . The hub  18  has a pentagonal cross section whose periphery does not vary with height, such that the hub  18  comprises five identical joint surfaces  20  which are vertical. The upper end of each top side piece  16   a  joins the hub  18  at a joint surface  20 . 
     Two lower central support structures  14   b  are also provided. Each of the lower central support structure  14  comprise a hub  18  that is of the same design as the hub  20  of the upper central support structure  14 . Each hub  18  is positioned with its centre positioned on the central axis  11  of the tree  10 . In the lower central support structure  14   b , the hub  18  is joined to the sides  12  by five spokes  22 . For each spoke  22 , one of its ends is joined to a joint surface  20  of the hub  18  and its other end is joined to an intermediate side piece  16   b . The spokes  22  extend horizontally from the hub  18  which is positioned centrally within the tree  10 . Each spoke  22  in a lower central support structure  14   b  has the same length as the other spokes  22  in the lower central support structure  14   b . However, the tapering shape of the Christmas tree  10  requires the length of the spokes  22  to vary between the lower central support structures  14   b , with the length increasing from top to bottom of the tree  10 . 
     The central support structures  14  are provided for every other level of side pieces  14  such that alternate side pieces  14  of each side  12  are supported by a central support structure  14 . The top side piece  16   a  of each side  12  is supported by the upper central support structure  14   a , and the second and fourth intermediate side pieces  16   b  of each side  12  are supported by the lower central support structures  14   b . Hence, the modular Christmas tree  10  comprises three tiers  24 , each tier  24  comprising a central support structure  14  and ten side pieces  16 . A first level of five of the side pieces  16  being supported directly by the central support structure  14  and a further level of five side pieces  16  arranged above and joined directly to the side pieces  16  of the first level, and so the five side pieces  16  of the further level are indirectly supported by the central support structure  14 .  FIG. 4  shows one of the tiers  24  including a lower central support structure  14   b . As will be appreciated, a modular Christmas tree  10  of greater or lesser height may be made by simply adding or removing tiers  24 . Some examples are shown in  FIGS. 12 to 16 , and these will be described in further detail below. 
     The hubs,  18 , spokes  22  and side pieces  16  are held in place using connectors which, in this example, are provided by dowels  26  that are received within co-operating holes of a constant (or substantially constant) width to form dowelled butt joints. All dowels  26  are of a common design such that they have the same size and shape. In this example, the dowels  26  are round in cross-section, although other shapes such as oval, race-track, square or rectangular cross sections may be used. How the hubs,  18 , spokes  22  and side pieces  16  connect together such that they may be separated as required for disassembly and storage of the tree  10  will now be explained with reference to  FIGS. 5 to 10 . 
     The intermediate side pieces  16   b  and the bottom side pieces  16   c  all share a common design that corresponds to that shown in  FIG. 5 . Each intermediate and bottom side piece  16   b  and  16   c  is elongate, and is also taller than it is deep. In this example, the intermediate and bottom side pieces  16   b  and  16   c  have dimensions of 325 mm×44 mm×19 mm. Hence, each of the intermediate and bottom side pieces  16   b  and  16   c  comprise two ends  30 , two wide edges  32  and two narrow edges  34 . 
     The ends  30  are cut obliquely at the same angle (to provide internal angles of 45° and 135° in this example) so that the intermediate and bottom side pieces  16   b  and  16   c  form parallelograms when viewed from the side (parallelogram according to UK English). Each of the intermediate and bottom side pieces  16   b  and  16   c  is provided with five blind holes  28  that are the same width as each dowel  26  and half the length of each dowel  26 . A pair of blind holes  28  is provided in each narrow edge  34  where the narrow edges  34  meet the ends  30  at an obtuse angle, as can be seen in  FIG. 5 . The holes  28  in each pair are aligned along the length of the side piece  16 . The fifth blind hole  28  of each of the intermediate and bottom side pieces  16   b  and  16   c  is provided centrally midway along one of the narrow edges  34 . 
       FIG. 6  shows that the top side pieces  16   a  all share a common design that differs slightly from the intermediate and bottom side pieces  16   b  and  16   c . One end  36   a  of each top side piece  16   a  is the same as the ends  30  of the intermediate and bottom side pieces  16   b  and  16   c . This end  36   a  joins to an intermediate side piece  16   b . The other end  36   b  joins to the top hub  18  and comprises two sides, namely a short side  136   b  and a long side  236   b  which meet at a right angle. The long side  236   b  abuts against a vertical joint surface  20  of the top hub  18  such that the right angle aligns with the top of the top hub  18  when the modular Christmas tree  10  is assembled. Hence, the long side  236   b  is vertical when the Christmas tree  10  is assembled and the short side  136   b  extends a short distance horizontally from the top of the top hub  18 . The orientation of the long side  236   b  relative to the edges  32  and  34  determine the angle to the vertical made by the sides  12  of the modular Christmas tree  10 , as will be described in more detail below. 
     As best seen in  FIG. 6 , each top side piece  16   a  has an approximate trapezium shape when viewed from the side (if the short side  136   b  is ignored, and taking the UK English meaning of trapezium). Thus, unlike the intermediate and bottom side pieces  16   b  and  16   c , the top side pieces  16   a  have one narrow edge  40   a  that is shorter than the other narrow edge  40   b . The shorter narrow edge  40   a  is provided with the central hole  28  and the pair of holes  28  adjacent end  36   a , as for the intermediate and bottom side pieces  16   b  and  16   c . The long side  236   b  of end  36   b  is provided with a fourth blind hole  28 , which also the same width as each dowel  26  and half the length of each dowel  26 . In this example, the top side pieces  16   a  have dimensions of 370 mm×44 mm×19 mm. 
     To assemble each side  12 , a top side piece  16   a  is joined to an intermediate side piece  16   b  by placing a dowel  26  into each blind hole  28  of a pair of blind holes  28  of either the top side piece  16   a  or the intermediate side piece  16   b . Then, the remaining exposed portions of the dowels  26  are inserted into each blind hole  28  of a pair of bind holes  28  of the other of the top side piece  16   a  or the intermediate side piece  16   b , thereby joining the top side piece  16   a  and the intermediate side piece  16   b . The intermediate side piece  16   b  is aligned such that the blind hole  28  provided in its narrow edge  34  is on the same side as the blind hole  28  provided in the long side  236   b  of the top side piece  16   a . In this embodiment, blind holes  28  have a constant (or substantially constant) width and are sized to match the dowels  26  to provide a snug fit, such that the top side piece  16   a  and the intermediate side piece  16   b  require reasonable force to be applied to pull them apart. Providing a pair of dowels  28  to each joint between the top side piece  16   a  and the intermediate side piece  16   b  provides the desired alignment between the side pieces  16   a  and  16   b , and provides the required strength for the sides  12  to be self-supporting. Both ends  30  of the intermediate side piece  16   b  will be aligned with the end  36   a  of the top piece  16   a.    
     Next, a further intermediate side piece  16   b  is joined to the existing intermediate side piece  16   b . A further pair of dowels  26  are used to join the unused pair of blind holes  28  from the existing intermediate side piece  16   b  with a pair of blind holes  28  of the further intermediate side piece  16   b . The intermediate side pieces  16   b  are aligned such that the blind holes  28  provided in their narrow edges  34  are all on the same side. This step is repeated to make up the required number of side pieces  16  for each side  12 . For the Christmas tree  10  of  FIGS. 1 to 3 , this step is repeated four times to produce sides  12  having a top side piece  16   a , four intermediate side pieces  16   b  and a bottom side piece  16   c  (remembering that the design of the intermediate side pieces  16   b  and bottom side piece  16   c  is the same). When complete, a side  10  like that shown in  FIG. 9  is produced. All ends  30  of the intermediate side pieces  16   b  will be aligned at the same angle. The ends  30  may be horizontal or may be aligned at a different angle, for example to create an overhang. As noted above, the angle adopted by the ends  30  is determined by the orientation of the long side  236   b  of the end  36   b  relative to the edges  32  and  34  of the top sidepiece  16   a.    
     It does not matter in which order the side pieces  16  are assembled. Although the preceding description starts with the top side piece  16   a  and an intermediate side piece  16   b , assembly of a side  12  may start with two intermediate side pieces  16   b  or an intermediate side piece  16   b  and a bottom side piece  16   c.    
     The central support structures  14  will now be described in more detail. All hubs  18  in the Christmas tree  10  of  FIGS. 1 to 3  share the common design of hub  18  shown in  FIG. 7 . Each hub  18  has a pentagonal top surface  42  and a pentagonal bottom surface  44 , and five joint surfaces  20  arranged around its sides. In this example, the hubs  18  have dimensions of 60 mm×63 mm×44 mm. A blind hole  28  is provided centrally in each joint surface  20 . A further blind hole  28  is provided centrally in the top surface  42 . Each blind hole  28  has the same width as each dowel  26  and half the length of each dowel  26 . 
     For the upper central support structure  14   a , each top side piece  16   a  is joined directly to the top hub  18  using dowels  26 . Namely, to continue assembly of the Christmas tree  10 , a dowel  26  is placed into each hole  28  provided in the five joint surfaces  20 . Then, the top side piece  16   a  of each side  12  is joined to the hub  18  by inserting an exposed end of a dowel  26  into the blind hole  28  provided in the long side  236   b  of the end  36   b  of the top side piece  16   a . With all five sides  12  joined to the top hub  18  in this way, the Christmas tree  10  is loosely held together although the lower central support structures  14   b  are required to strengthen the tree  10  and hold the sides  12  in true alignment and at the desired angle to the vertical. 
     The spokes  22  from each lower central support structure  14   b  share a common design that corresponds to that shown in  FIG. 8 . Each spoke  22  is elongate along its length, and is also taller than it is wide. Hence, each spoke  22  comprises two ends  46 , two wide edges  48  and two narrow edges  50 . One end  46   a  is cut square and the other end  46   b  is cut obliquely to match the angle that the sides  12  make to the vertical. Each of the spokes  22  is provided with two blind holes  28  that are the same width as each dowel  26  and half the length of each dowel  26 . One blind hole  28  is provided in each end  46  of a spoke  22 . As noted above, the spokes  22  of different lower central support structures  14   b  have different lengths. In this example, the upper spokes  22  have dimensions of 195 mm×44 mm×19 mm and the lower spokes  22  have dimensions of 310 mm×44 mm×19 mm. The ends of the spokes  22  remain the same, and the length of the plain, middle portion of each spoke  22  is increased or decreased. This ensures that the square end  46   a  remains square and the oblique end  46   b  terminates with the same angle for all spokes  22 . 
     The spokes  22  may be joined to the hubs  18  of the lower central support structures  14   b  as follows. A dowel  26  is placed into each hole  28  provided in the five joint surfaces  20  of the hub  18 . Then, each spoke  22  is joined to the hub  18  by inserting an exposed end of a dowel  26  into the blind hole  28  provided in the square end  46   a  of the spoke  22 .  FIG. 10  shows a lower central support structure  14   b  formed in this way with all five spokes  22  joined to the hub  18 . 
     Assembly of the modular Christmas tree  10  is continued by joining the lower central support structures  14   b  to the sides  12  of the tree  10 . Dowels  26  are placed in the blind holes  28  provided in the oblique end  46   b  of each spoke  22 . Each lower central support structure  14   b  is then offered up to the sides  12  of the tree  10  at the correct height (i.e. the correct level of side pieces  16  such that the spokes  22  extend to meet those side pieces  16 ). The blind hole  28  provided in the narrow edge  34  of each intermediate side piece  16   b  is pushed onto the exposed portion of one of the dowels  26 . When all five spokes  22  of each of the pair of lower central support structures  14   b  are joined in this way, the modular Christmas tree  10  of  FIGS. 1 to 3  is formed. All components are joined by dowelled butt joints and the components are shaped such that the surfaces of the joined components abut against each other when the components are pushed fully together. With the Christmas tree  10  fully assembled in this way, the sides  12  and central support structures  14  provide rigidity to the tree  10 , and also ensure the correct alignment of the sides  12 . 
     When assembled, the ends  36   b  of the top side pieces  16   a  will be aligned vertically where they meet the top hub  18 , as described above. In this example, the long sides  236   b  of the top side pieces  16  are angled relative to the edges  32  and  34  such that the ends  36   a  and  30  of the intermediate and bottom side pieces  16   b  and  16   c  are angled slightly away from the horizontal (by 15°) thereby creating an overhang to each end  36   a  and  30 . This also means that bottom end  30  of the bottom side pieces  16   c  does not rest flat against a level floor. Instead, just the edge of the bottom end  30  contacts the floor. The reduced contact area has been found to provide more grip with the floor. Alternatively, the long sides  236   b  of the top side pieces  16  may be angled relative to the edges  32  and  34  such that the ends  36   a  and  30  of the intermediate and bottom side pieces  16   b  and  16   c  adopt angles other than 15° from the horizontal, or may be aligned with the horizontal. In the latter case, the bottom end  30  of the bottom side pieces  16   c  will rest flat against a level floor. Also, the angle the ends  36   a  and  30  of the intermediate and bottom side pieces  16   b  and  16   c  adopt may also be varied by altering the angle at which the ends  36  and  30  are cut from the 45° described above. 
     The hole  28  provided in the top surface  42  of the top hub  18  allows further decorative items like a star or fairy to be mounted on top of the tree  10 . The decorative item may be mounted to the tree  10  directly by being placed into the hole  28 , or indirectly by having a further mounting structure such as a mast placed into the hole  28 . An attachment may also be fixed to the hole  28  provided in the top surface  42  of the top hub  18  to allow the modular Christmas tree  10  to be suspended from a structure such as a ceiling. The attachment may be a hook. 
     Further decoration may be added to the modular Christmas tree  10 . Tinsel, ribbons or lights may be strung around the tree  10 , for example using the ends  30  of the side pieces  16  that provide a horizontal surface for supporting such items when the tree  10  is assembled. Alternatively, the side pieces  16  may be provided with features to allow decorations to be hung, for example holes, hooks or notches. As the modular Christmas tree  10  does not include a supporting trunk, a large, uninterrupted storage area results at the base of the tree  10 . This may be used to store Christmas presents. Hence, the modular Christmas tree  10  addresses some of the disadvantages of real and traditional artificial Christmas trees, whilst providing the same focal point of a Christmas tree during the festive season. 
     The modular Christmas tree  10  may be made from many different materials. Wood is preferred, although not essential. For example, the tree  10  of  FIGS. 1 to 3  is made entirely of wood. Any hardwood may be used and will create an attractive appearance. However, less expensive modular Christmas trees  10  may be made from softwood or processed wood such as chipboard or fibre boards like mdf. The dowels  26 , which are hidden from view when assembled, are well suited to the use of softwood. While wood is a preferred material as it provides a more environmentally friendly Christmas tree  10 , this does not preclude the use of metals or even plastics for all or some of components of the tree  10 . In order to offset some environmental disadvantages of using plastic and metal parts, the parts could be made using additive manufacturing processes which would reduce waste when compared with reductive manufacturing processes like that required when making wooden components. 
     Each side piece  16  is aligned at 30° to the vertical. However, the overlap of adjacent side pieces  16  means that the overall angle of each side  12  to the vertical is less. The example Christmas tree  10  of  FIG. 1  is approximately 1.5 m tall and has a base diameter of approximately 1.2 m, giving an overall angle of approximately 21° for each side  12 . For the side pieces  16  of the Christmas tree  10  of  FIGS. 1 to 3 , a range of or 25° to 35° (which may be approximate) to the vertical and an overlap of between 30 mm and 100 mm has been found to provide a pleasing overall appearance to the modular Christmas tree  10  with the length of intermediate side piece  16   b  described, however, the overlap could vary more greatly with the use of longer intermediate side pieces  16   b . These values may be varied to create different appearances to a tree  10  to suit individual tastes. 
     The modular Christmas tree  10  may be easily dissembled at the end of the festive season so as to allow compact storage. The side pieces  16 , spokes  22  and hubs  18  may be pulled apart. The dowels  26  may be removed from the blind holes  28 , or may be left in place as they occupy little additional space. The disassembled side pieces  16 , spokes  22 , hubs  18  and dowels  26  may then be packed into a box  52  for storage.  FIG. 11  shows the 1.5 m by 1.2 m Christmas tree  10  of  FIGS. 1 to 3  packed into a box  52  which has external dimensions of 0.5 m×0.35 m×0.1 m, giving a volume of only 0.0175 m 3 . As will be appreciated, this is much more compact than traditional artificial Christmas trees. The storage requirements of an equivalently-sized artificial tree are typically 1.25 m×0.5 m×0.35 m, giving a much larger volume of 0.22 m 3 . This difference is best illustrated by considering that twelve of the modular Christmas trees  10  of  FIGS. 1 to 3  could be stored in a single box intended for a traditional tree. 
     For any particular modular Christmas tree  10 , the size of the box  52  can be very small as it merely has to include one dimension that is at least the same length as the longest component of the tree  10 . 
     A person skilled in the art will appreciate that the above embodiments may be varied in many different respects without departing from the scope of the present invention that is defined by the appended claims. 
     The number of sides  12  of the modular Christmas tree  10  may be varied from the five shown in  FIGS. 1 to 3 . Also, the number of side pieces  16  in each side  12  may be varied from the six shown in  FIGS. 1 to 3 . Increasing and decreasing the number of side pieces  16  in each side  12  may alter the height and width of the tree  10 , so a different number of central support structures  14  may be used when compared with the three central support structures  14  shown in  FIGS. 1 to 3 . Also, the length of the side pieces  16  may be varied (and the length of side pieces  16  in a single tree  10  may be varied, for example to have shorter side pieces  16  towards the top of the tree  10 ), as too may the angle the side pieces  16  make to the vertical when the tree  10  is assembled. Various examples are shown in  FIGS. 12 to 16 . 
       FIG. 12  shows a modular Christmas tree  10  having an additional side piece  16  added to each side  12  of the lowest tier  24  relative to the tree  10  of  FIGS. 1 to 3 . Hence, each side  12  comprises seven side pieces  16 , and the tree  10  still comprises three central support structures  14 . 
       FIG. 13  shows a shorter modular Christmas tree  10  having only four sides  12 , with four side pieces  15  per side  12 . The tree  10  also requires only two central support structures  14 . The hubs  18  are now square in cross section when viewed from above, thereby providing four joint surfaces  20  around the sides of each hub  18 . 
       FIG. 14  shows a taller modular Christmas tree  10  having only three sides  12 , but eight side pieces  16  per side  12 . The increased height of the tree  10  is supported by four central support structures  14 . With three sides  12 , the hubs  18  could be triangular in cross section when viewed from above. However, in this tree  10  of  FIG. 14 , hubs  18  with a hexagonal cross section are used, with alternate sides being used as joint surfaces  20  joined to either the top side pieces  16   a  or spokes  22 . Blind holes  28  may be provided in just the alternate sides. Alternatively, blind holes  28  may be provided in each of the six sides. This is advantageous as it allows a stock of a common hexagonal hubs  18  to be used for both three-sided and six-sided modular Christmas trees  10 . 
       FIG. 15  shows another taller modular Christmas tree  10  having six sides  12  and eight side pieces  16  per side  12 . The tree  10  is supported by four central support structures  14 , each having a hexagonal hub  18 . 
     A further variation is shown in  FIG. 16 . Not all levels of this modular Christmas tree  10  have the same number of side pieces  16 . The bottom four levels comprise six sides  12  and are supported by two central support structures  14  with hexagonal hubs  18 . Alternate sides  12  continue beyond the fourth level, such that there are four upper levels comprising three sides  12 . The upper levels are supported by two central support structures  14  having hexagonal hubs  18  with only alternate sides  12  providing joint surfaces  20 . 
     The modular Christmas trees  10  are primarily designed for domestic use such as in the home or office. Accordingly, typical heights of the tree  10  could be from 0.5 m to 3 m. However, taller trees are of course possible, for example trees  10  could be 5 m or more tall and may be used for outdoors display. 
     The modular nature of the artificial Christmas tree  10  allows further flexibility in how the tree  10  is used. For example, a modular Christmas tree  10  may be used in corners or against a flat wall. When used against a flat wall, one or more sides  12  and their supporting spokes  22  may be omitted. Where the tree  10  has an even number of sides  12 , the tree  10  may then be stood flush against the flat wall. For instance, the six-sided tree  10  of  FIG. 15  may have two adjacent sides  12  omitted as well as the spokes  22  supporting these omitted sides  12 . The tree  10  may then be placed such that the remaining sides  12  separated by 180° rest against the flat wall. For a 270° corner, one or more sides  12  may be omitted from the tree  10  if necessary. For example, the four-side tree  10  of  FIG. 13  may simply be placed against the corner. Five to eight-sided trees  10  may have a single side  12  omitted. 
     Although straight side pieces  16  are described above, other shapes may be used. The shape may be varied without departing from the desired Christmas tree shape. For example, the side pieces  16  may curve to be steeper at their tops and shallower at their bottoms when assembled. Other shapes and detailing may be provided to the side pieces  16 . Also, the spokes  22  need not be straight. The number of central support structures  14  may also be varied, and can be separated by more or less than the alternate levels shown in  FIGS. 1 to 3 , including a central support structure  14  for each level. Each central support structure  14  need not support every side  12 . For instance, one central support structure  14  may support half the sides  12 , and the adjacent central support structures  14  may support the other half of the sides  12 . 
     The trees  10  shown in the figures all include an upper central support structure  14   a  that does not have spokes  22 . This need not be the case. For instance, all central support structures  14  may have spokes  22 . The uppermost central support structure  14  may be provided at the second level of the side pieces  16 . In such an arrangement, a common design for all the side pieces  16  may be used as there is no longer a need for a different design to the top side pieces  16   a.    
     The spokes  22  shown in the figures are all unitary structures that provide a single part to span from the hub  18  to a side  12 . However, multipart spokes  22  may be used instead. For example, the unitary spokes  22  of the figures may be split into two or more parts that may be joined at their ends, for example using dowelled butt joints like those described above. 
     Cylindrical dowels  26  need not be used. Dowels  26  having cross-sectional shapes other than circles may be used, such as oval, race-track, square, rectangular, etc. Obviously, the blind holes  28  should have a corresponding cross-sectional shape. For non-circular cross-sectional shapes, only a single dowel  26  may be required to join the side pieces  16  to each other. For example, elongate race-track shapes may provide the strength and lack of rotational movement between two side pieces  16 . 
     A modification may be made to the shape of the blind holes  28 . In the embodiments described above, the blind holes  28  have a width that is constant and that corresponds to the width of the dowels  26 .  FIGS. 17 and 18  show a variation of this design where the blind holes  28  have a tapering shape so as to be wider at their opening than at their bottom. The size at the bottom of each blind hole  28  may correspond to the width of the dowel  26 . As seen more clearly in  FIG. 18 , each blind hole  28  comprises two steps and hence three sections  28   a,b,c  of narrowing size as each blind hole  28  deepens. The bottom section  28   c  has the same width as the dowel  26 . For example, if a 3 mm diameter dowel  26  is used, the diameter of section  28   c  may be 3.00 mm, the diameter of section  28   b  may be 3.05 mm and the diameter of section  28   a  may be 3.10 mm. Alternatively, the tapering may be gradual such that the blind hole  28  is frustoconical in shape. A tapering blind hole  28  provides greater tolerance when inserting the dowel  26  into the blind hole  28  and also eases separation of the joint when disassembling the Christmas tree  10 . 
     Also, joints other than dowelled butt joints may be used. Joints such as biscuit, mortise and tenon, dovetail and half lap joints may be used. These may all be made using all wooden parts. An alternative form of dowelled butt joint is shown in  FIGS. 17 and 18 . This joint makes use of conventional cam dowel and cam lock combinations frequently used with flat-pack furniture. 
       FIGS. 19 and 20  show two side pieces  16  joined in this alternative way. A pair of blind holes  28  of constant width is joined using a plain dowel  26 . However, the other of the pairs of blind holes  28  is modified. One blind hole  28  is merely made smaller and is used to accommodate the cam dowel  56 . The cam dowel  54  is provided with a thread  56  at one end and a screw head  58  at the other end. The cam dowel  56  is screwed into one side piece  16  using a screwdriver engaged with the screw head  58 . The other blind hole  28  of the pair is supplemented by a larger width blind hole  62  formed from the wide edge  32 . The hole  62  is sized to correspond to the cam lock  60  such that the cam lock  60  is accommodated in the hole  62 . As can be seen from  FIG. 19 , one side of the cam lock  60  is provided with a crosshead  64  to receive a screwdriver (a slot could be used instead of a crosshead  64  to receive a flat-bladed screwdriver). As is well known, the cam lock  60  also has an aperture provided in its side that is partly defined by a sloping cam surface. The cam lock  60  is placed in the hole  62  with the aperture facing the other blind hole  28 . The aperture is sized to receive the screw head  58  of the cam dowel  56  when the sidepieces  16  are placed together as shown in  FIG. 20  (the cam lock  60  is omitted from  FIG. 18  such that the position of the screw head  58  can be seen more clearly). A screwdriver is then used to rotate the cam lock  60 , such that the cam surface is urged against the screw head  58 , drawing the two sidepieces  16  into firm engagement with each other. Such a joint provides greater rigidity to the modular Christmas tree  10 , albeit with a modest increase in the amount of time required for assembly and disassembly. 
     Cam dowel and cam lock combinations may be used in the other joints if desired. For example, two such combinations may be used to join side pieces  16 , or combinations may be used to join an intermediate side piece  16   b  to spoke  22 , or to join a top side piece  16   a  to a hub  18  (in which case, the cam dowel  26  may be conveniently screwed into the hub  18  with the top side piece  16   a  being provided with the cam lock  60  and it accommodating hole  62 . 
     While examples of the order of assembly were provided above, many other orders are possible. For example, the central support structures  14  may be assembled prior to the sides  12 . Alternatively, the tree  10  may be assembled level by level. For example, an intermediate side piece  16   b  may be joined to a bottom side piece  16   c  for each of the sides, then a spoke  22  may be joined to each side  12 , and the spokes  22  then joined to a hub  18 . Next, two levels of side pieces  16  may be joined to each side  12 , and another central support structure  14  added, and so on. The order of disassembling the parts of the tree  10  may also be varied. It does not matter into which part a dowel  26  is first placed. For instance, a dowel may be placed into a hub  18  or into a spoke  22  when a hub  18  and spoke  22  are to be joined.